1 /* $NetBSD: mdb.c,v 1.3 2021/08/14 16:14:57 christos Exp $ */
2
3 /** @file mdb.c
4 * @brief Lightning memory-mapped database library
5 *
6 * A Btree-based database management library modeled loosely on the
7 * BerkeleyDB API, but much simplified.
8 */
9 /*
10 * Copyright 2011-2021 Howard Chu, Symas Corp.
11 * All rights reserved.
12 *
13 * Redistribution and use in source and binary forms, with or without
14 * modification, are permitted only as authorized by the OpenLDAP
15 * Public License.
16 *
17 * A copy of this license is available in the file LICENSE in the
18 * top-level directory of the distribution or, alternatively, at
19 * <http://www.OpenLDAP.org/license.html>.
20 *
21 * This code is derived from btree.c written by Martin Hedenfalk.
22 *
23 * Copyright (c) 2009, 2010 Martin Hedenfalk <martin@bzero.se>
24 *
25 * Permission to use, copy, modify, and distribute this software for any
26 * purpose with or without fee is hereby granted, provided that the above
27 * copyright notice and this permission notice appear in all copies.
28 *
29 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
30 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
31 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
32 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
33 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
34 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
35 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
36 */
37 #ifndef _GNU_SOURCE
38 #define _GNU_SOURCE 1
39 #endif
40 #if defined(__WIN64__)
41 #define _FILE_OFFSET_BITS 64
42 #endif
43 #ifdef _WIN32
44 #include <malloc.h>
45 #include <windows.h>
46 #include <wchar.h> /* get wcscpy() */
47
48 /** getpid() returns int; MinGW defines pid_t but MinGW64 typedefs it
49 * as int64 which is wrong. MSVC doesn't define it at all, so just
50 * don't use it.
51 */
52 #define MDB_PID_T int
53 #define MDB_THR_T DWORD
54 #include <sys/types.h>
55 #include <sys/stat.h>
56 #ifdef __GNUC__
57 # include <sys/param.h>
58 #else
59 # define LITTLE_ENDIAN 1234
60 # define BIG_ENDIAN 4321
61 # define BYTE_ORDER LITTLE_ENDIAN
62 # ifndef SSIZE_MAX
63 # define SSIZE_MAX INT_MAX
64 # endif
65 #endif
66 #else
67 #include <sys/types.h>
68 #include <sys/stat.h>
69 #define MDB_PID_T pid_t
70 #define MDB_THR_T pthread_t
71 #include <sys/param.h>
72 #include <sys/uio.h>
73 #include <sys/mman.h>
74 #ifdef HAVE_SYS_FILE_H
75 #include <sys/file.h>
76 #endif
77 #include <fcntl.h>
78 #endif
79
80 #if defined(__mips) && defined(__linux)
81 /* MIPS has cache coherency issues, requires explicit cache control */
82 #include <asm/cachectl.h>
83 extern int cacheflush(char *addr, int nbytes, int cache);
84 #define CACHEFLUSH(addr, bytes, cache) cacheflush(addr, bytes, cache)
85 #else
86 #define CACHEFLUSH(addr, bytes, cache)
87 #endif
88
89 #if defined(__linux) && !defined(MDB_FDATASYNC_WORKS)
90 /** fdatasync is broken on ext3/ext4fs on older kernels, see
91 * description in #mdb_env_open2 comments. You can safely
92 * define MDB_FDATASYNC_WORKS if this code will only be run
93 * on kernels 3.6 and newer.
94 */
95 #define BROKEN_FDATASYNC
96 #endif
97
98 #include <errno.h>
99 #include <limits.h>
100 #include <stddef.h>
101 #include <inttypes.h>
102 #include <stdio.h>
103 #include <stdlib.h>
104 #include <string.h>
105 #include <time.h>
106
107 #ifdef _MSC_VER
108 #include <io.h>
109 typedef SSIZE_T ssize_t;
110 #else
111 #include <unistd.h>
112 #endif
113
114 #if defined(__sun) || defined(ANDROID)
115 /* Most platforms have posix_memalign, older may only have memalign */
116 #define HAVE_MEMALIGN 1
117 #include <malloc.h>
118 /* On Solaris, we need the POSIX sigwait function */
119 #if defined (__sun)
120 # define _POSIX_PTHREAD_SEMANTICS 1
121 #endif
122 #endif
123
124 #if !(defined(BYTE_ORDER) || defined(__BYTE_ORDER))
125 #include <netinet/in.h>
126 #include <resolv.h> /* defines BYTE_ORDER on HPUX and Solaris */
127 #endif
128
129 #if defined(__FreeBSD__) && defined(__FreeBSD_version) && __FreeBSD_version >= 1100110
130 # define MDB_USE_POSIX_MUTEX 1
131 # define MDB_USE_ROBUST 1
132 #elif defined(__APPLE__) || defined (BSD) || defined(__FreeBSD_kernel__)
133 # define MDB_USE_POSIX_SEM 1
134 # define MDB_FDATASYNC fsync
135 #elif defined(ANDROID)
136 # define MDB_FDATASYNC fsync
137 #endif
138
139 #ifndef _WIN32
140 #include <pthread.h>
141 #include <signal.h>
142 #ifdef MDB_USE_POSIX_SEM
143 # define MDB_USE_HASH 1
144 #include <semaphore.h>
145 #else
146 #define MDB_USE_POSIX_MUTEX 1
147 #endif
148 #endif
149
150 #if defined(_WIN32) + defined(MDB_USE_POSIX_SEM) \
151 + defined(MDB_USE_POSIX_MUTEX) != 1
152 # error "Ambiguous shared-lock implementation"
153 #endif
154
155 #ifdef USE_VALGRIND
156 #include <valgrind/memcheck.h>
157 #define VGMEMP_CREATE(h,r,z) VALGRIND_CREATE_MEMPOOL(h,r,z)
158 #define VGMEMP_ALLOC(h,a,s) VALGRIND_MEMPOOL_ALLOC(h,a,s)
159 #define VGMEMP_FREE(h,a) VALGRIND_MEMPOOL_FREE(h,a)
160 #define VGMEMP_DESTROY(h) VALGRIND_DESTROY_MEMPOOL(h)
161 #define VGMEMP_DEFINED(a,s) VALGRIND_MAKE_MEM_DEFINED(a,s)
162 #else
163 #define VGMEMP_CREATE(h,r,z)
164 #define VGMEMP_ALLOC(h,a,s)
165 #define VGMEMP_FREE(h,a)
166 #define VGMEMP_DESTROY(h)
167 #define VGMEMP_DEFINED(a,s)
168 #endif
169
170 #ifndef BYTE_ORDER
171 # if (defined(_LITTLE_ENDIAN) || defined(_BIG_ENDIAN)) && !(defined(_LITTLE_ENDIAN) && defined(_BIG_ENDIAN))
172 /* Solaris just defines one or the other */
173 # define LITTLE_ENDIAN 1234
174 # define BIG_ENDIAN 4321
175 # ifdef _LITTLE_ENDIAN
176 # define BYTE_ORDER LITTLE_ENDIAN
177 # else
178 # define BYTE_ORDER BIG_ENDIAN
179 # endif
180 # else
181 # define BYTE_ORDER __BYTE_ORDER
182 # endif
183 #endif
184
185 #ifndef LITTLE_ENDIAN
186 #define LITTLE_ENDIAN __LITTLE_ENDIAN
187 #endif
188 #ifndef BIG_ENDIAN
189 #define BIG_ENDIAN __BIG_ENDIAN
190 #endif
191
192 #if defined(__i386) || defined(__x86_64) || defined(_M_IX86)
193 #define MISALIGNED_OK 1
194 #endif
195
196 #include "lmdb.h"
197 #include "midl.h"
198
199 #if (BYTE_ORDER == LITTLE_ENDIAN) == (BYTE_ORDER == BIG_ENDIAN)
200 # error "Unknown or unsupported endianness (BYTE_ORDER)"
201 #elif (-6 & 5) || CHAR_BIT != 8 || UINT_MAX < 0xffffffff || ULONG_MAX % 0xFFFF
202 # error "Two's complement, reasonably sized integer types, please"
203 #endif
204
205 #ifdef __GNUC__
206 /** Put infrequently used env functions in separate section */
207 # ifdef __APPLE__
208 # define ESECT __attribute__ ((section("__TEXT,text_env")))
209 # else
210 # define ESECT __attribute__ ((section("text_env")))
211 # endif
212 #else
213 #define ESECT
214 #endif
215
216 #ifdef _WIN32
217 #define CALL_CONV WINAPI
218 #else
219 #define CALL_CONV
220 #endif
221
222 /** @defgroup internal LMDB Internals
223 * @{
224 */
225 /** @defgroup compat Compatibility Macros
226 * A bunch of macros to minimize the amount of platform-specific ifdefs
227 * needed throughout the rest of the code. When the features this library
228 * needs are similar enough to POSIX to be hidden in a one-or-two line
229 * replacement, this macro approach is used.
230 * @{
231 */
232
233 /** Features under development */
234 #ifndef MDB_DEVEL
235 #define MDB_DEVEL 0
236 #endif
237
238 /** Wrapper around __func__, which is a C99 feature */
239 #if __STDC_VERSION__ >= 199901L
240 # define mdb_func_ __func__
241 #elif __GNUC__ >= 2 || _MSC_VER >= 1300
242 # define mdb_func_ __FUNCTION__
243 #else
244 /* If a debug message says <mdb_unknown>(), update the #if statements above */
245 # define mdb_func_ "<mdb_unknown>"
246 #endif
247
248 /* Internal error codes, not exposed outside liblmdb */
249 #define MDB_NO_ROOT (MDB_LAST_ERRCODE + 10)
250 #ifdef _WIN32
251 #define MDB_OWNERDEAD ((int) WAIT_ABANDONED)
252 #elif defined(MDB_USE_POSIX_MUTEX) && defined(EOWNERDEAD)
253 #define MDB_OWNERDEAD EOWNERDEAD /**< #LOCK_MUTEX0() result if dead owner */
254 #endif
255
256 #ifdef __GLIBC__
257 #define GLIBC_VER ((__GLIBC__ << 16 )| __GLIBC_MINOR__)
258 #endif
259 /** Some platforms define the EOWNERDEAD error code
260 * even though they don't support Robust Mutexes.
261 * Compile with -DMDB_USE_ROBUST=0, or use some other
262 * mechanism like -DMDB_USE_POSIX_SEM instead of
263 * -DMDB_USE_POSIX_MUTEX.
264 * (Posix semaphores are not robust.)
265 */
266 #ifndef MDB_USE_ROBUST
267 /* Android currently lacks Robust Mutex support. So does glibc < 2.4. */
268 # if defined(MDB_USE_POSIX_MUTEX) && (defined(ANDROID) || \
269 (defined(__GLIBC__) && GLIBC_VER < 0x020004))
270 # define MDB_USE_ROBUST 0
271 # else
272 # define MDB_USE_ROBUST 1
273 # endif
274 #endif /* !MDB_USE_ROBUST */
275
276 #if defined(MDB_USE_POSIX_MUTEX) && (MDB_USE_ROBUST)
277 /* glibc < 2.12 only provided _np API */
278 # if (defined(__GLIBC__) && GLIBC_VER < 0x02000c) || \
279 (defined(PTHREAD_MUTEX_ROBUST_NP) && !defined(PTHREAD_MUTEX_ROBUST))
280 # define PTHREAD_MUTEX_ROBUST PTHREAD_MUTEX_ROBUST_NP
281 # define pthread_mutexattr_setrobust(attr, flag) pthread_mutexattr_setrobust_np(attr, flag)
282 # define pthread_mutex_consistent(mutex) pthread_mutex_consistent_np(mutex)
283 # endif
284 #endif /* MDB_USE_POSIX_MUTEX && MDB_USE_ROBUST */
285
286 #if defined(MDB_OWNERDEAD) && (MDB_USE_ROBUST)
287 #define MDB_ROBUST_SUPPORTED 1
288 #endif
289
290 #ifdef _WIN32
291 #define MDB_USE_HASH 1
292 #define MDB_PIDLOCK 0
293 #define THREAD_RET DWORD
294 #define pthread_t HANDLE
295 #define pthread_mutex_t HANDLE
296 #define pthread_cond_t HANDLE
297 typedef HANDLE mdb_mutex_t, mdb_mutexref_t;
298 #define pthread_key_t DWORD
299 #define pthread_self() GetCurrentThreadId()
300 #define pthread_key_create(x,y) \
301 ((*(x) = TlsAlloc()) == TLS_OUT_OF_INDEXES ? ErrCode() : 0)
302 #define pthread_key_delete(x) TlsFree(x)
303 #define pthread_getspecific(x) TlsGetValue(x)
304 #define pthread_setspecific(x,y) (TlsSetValue(x,y) ? 0 : ErrCode())
305 #define pthread_mutex_unlock(x) ReleaseMutex(*x)
306 #define pthread_mutex_lock(x) WaitForSingleObject(*x, INFINITE)
307 #define pthread_cond_signal(x) SetEvent(*x)
308 #define pthread_cond_wait(cond,mutex) do{SignalObjectAndWait(*mutex, *cond, INFINITE, FALSE); WaitForSingleObject(*mutex, INFINITE);}while(0)
309 #define THREAD_CREATE(thr,start,arg) \
310 (((thr) = CreateThread(NULL, 0, start, arg, 0, NULL)) ? 0 : ErrCode())
311 #define THREAD_FINISH(thr) \
312 (WaitForSingleObject(thr, INFINITE) ? ErrCode() : 0)
313 #define LOCK_MUTEX0(mutex) WaitForSingleObject(mutex, INFINITE)
314 #define UNLOCK_MUTEX(mutex) ReleaseMutex(mutex)
315 #define mdb_mutex_consistent(mutex) 0
316 #define getpid() GetCurrentProcessId()
317 #define MDB_FDATASYNC(fd) (!FlushFileBuffers(fd))
318 #define MDB_MSYNC(addr,len,flags) (!FlushViewOfFile(addr,len))
319 #define ErrCode() GetLastError()
320 #define GET_PAGESIZE(x) {SYSTEM_INFO si; GetSystemInfo(&si); (x) = si.dwPageSize;}
321 #define close(fd) (CloseHandle(fd) ? 0 : -1)
322 #define munmap(ptr,len) UnmapViewOfFile(ptr)
323 #ifdef PROCESS_QUERY_LIMITED_INFORMATION
324 #define MDB_PROCESS_QUERY_LIMITED_INFORMATION PROCESS_QUERY_LIMITED_INFORMATION
325 #else
326 #define MDB_PROCESS_QUERY_LIMITED_INFORMATION 0x1000
327 #endif
328 #define Z "I"
329 #else
330 #define THREAD_RET void *
331 #define THREAD_CREATE(thr,start,arg) pthread_create(&thr,NULL,start,arg)
332 #define THREAD_FINISH(thr) pthread_join(thr,NULL)
333 #define Z "z" /**< printf format modifier for size_t */
334
335 /** For MDB_LOCK_FORMAT: True if readers take a pid lock in the lockfile */
336 #define MDB_PIDLOCK 1
337
338 #ifdef MDB_USE_POSIX_SEM
339
340 typedef sem_t *mdb_mutex_t, *mdb_mutexref_t;
341 #define LOCK_MUTEX0(mutex) mdb_sem_wait(mutex)
342 #define UNLOCK_MUTEX(mutex) sem_post(mutex)
343
344 static int
mdb_sem_wait(sem_t * sem)345 mdb_sem_wait(sem_t *sem)
346 {
347 int rc;
348 while ((rc = sem_wait(sem)) && (rc = errno) == EINTR) ;
349 return rc;
350 }
351
352 #else /* MDB_USE_POSIX_MUTEX: */
353 /** Shared mutex/semaphore as the original is stored.
354 *
355 * Not for copies. Instead it can be assigned to an #mdb_mutexref_t.
356 * When mdb_mutexref_t is a pointer and mdb_mutex_t is not, then it
357 * is array[size 1] so it can be assigned to the pointer.
358 */
359 typedef pthread_mutex_t mdb_mutex_t[1];
360 /** Reference to an #mdb_mutex_t */
361 typedef pthread_mutex_t *mdb_mutexref_t;
362 /** Lock the reader or writer mutex.
363 * Returns 0 or a code to give #mdb_mutex_failed(), as in #LOCK_MUTEX().
364 */
365 #define LOCK_MUTEX0(mutex) pthread_mutex_lock(mutex)
366 /** Unlock the reader or writer mutex.
367 */
368 #define UNLOCK_MUTEX(mutex) pthread_mutex_unlock(mutex)
369 /** Mark mutex-protected data as repaired, after death of previous owner.
370 */
371 #define mdb_mutex_consistent(mutex) pthread_mutex_consistent(mutex)
372 #endif /* MDB_USE_POSIX_SEM */
373
374 /** Get the error code for the last failed system function.
375 */
376 #define ErrCode() errno
377
378 /** An abstraction for a file handle.
379 * On POSIX systems file handles are small integers. On Windows
380 * they're opaque pointers.
381 */
382 #define HANDLE int
383
384 /** A value for an invalid file handle.
385 * Mainly used to initialize file variables and signify that they are
386 * unused.
387 */
388 #define INVALID_HANDLE_VALUE (-1)
389
390 /** Get the size of a memory page for the system.
391 * This is the basic size that the platform's memory manager uses, and is
392 * fundamental to the use of memory-mapped files.
393 */
394 #define GET_PAGESIZE(x) ((x) = sysconf(_SC_PAGE_SIZE))
395 #endif
396
397 #if defined(_WIN32) || defined(MDB_USE_POSIX_SEM)
398 #define MNAME_LEN 32
399 #else
400 #define MNAME_LEN (sizeof(pthread_mutex_t))
401 #endif
402
403 /** @} */
404
405 #ifdef MDB_ROBUST_SUPPORTED
406 /** Lock mutex, handle any error, set rc = result.
407 * Return 0 on success, nonzero (not rc) on error.
408 */
409 #define LOCK_MUTEX(rc, env, mutex) \
410 (((rc) = LOCK_MUTEX0(mutex)) && \
411 ((rc) = mdb_mutex_failed(env, mutex, rc)))
412 static int mdb_mutex_failed(MDB_env *env, mdb_mutexref_t mutex, int rc);
413 #else
414 #define LOCK_MUTEX(rc, env, mutex) ((rc) = LOCK_MUTEX0(mutex))
415 #define mdb_mutex_failed(env, mutex, rc) (rc)
416 #endif
417
418 #ifndef _WIN32
419 /** A flag for opening a file and requesting synchronous data writes.
420 * This is only used when writing a meta page. It's not strictly needed;
421 * we could just do a normal write and then immediately perform a flush.
422 * But if this flag is available it saves us an extra system call.
423 *
424 * @note If O_DSYNC is undefined but exists in /usr/include,
425 * preferably set some compiler flag to get the definition.
426 */
427 #ifndef MDB_DSYNC
428 # ifdef O_DSYNC
429 # define MDB_DSYNC O_DSYNC
430 # else
431 # define MDB_DSYNC O_SYNC
432 # endif
433 #endif
434 #endif
435
436 /** Function for flushing the data of a file. Define this to fsync
437 * if fdatasync() is not supported.
438 */
439 #ifndef MDB_FDATASYNC
440 # define MDB_FDATASYNC fdatasync
441 #endif
442
443 #ifndef MDB_MSYNC
444 # define MDB_MSYNC(addr,len,flags) msync(addr,len,flags)
445 #endif
446
447 #ifndef MS_SYNC
448 #define MS_SYNC 1
449 #endif
450
451 #ifndef MS_ASYNC
452 #define MS_ASYNC 0
453 #endif
454
455 /** A page number in the database.
456 * Note that 64 bit page numbers are overkill, since pages themselves
457 * already represent 12-13 bits of addressable memory, and the OS will
458 * always limit applications to a maximum of 63 bits of address space.
459 *
460 * @note In the #MDB_node structure, we only store 48 bits of this value,
461 * which thus limits us to only 60 bits of addressable data.
462 */
463 typedef MDB_ID pgno_t;
464
465 /** A transaction ID.
466 * See struct MDB_txn.mt_txnid for details.
467 */
468 typedef MDB_ID txnid_t;
469
470 /** @defgroup debug Debug Macros
471 * @{
472 */
473 #ifndef MDB_DEBUG
474 /** Enable debug output. Needs variable argument macros (a C99 feature).
475 * Set this to 1 for copious tracing. Set to 2 to add dumps of all IDLs
476 * read from and written to the database (used for free space management).
477 */
478 #define MDB_DEBUG 0
479 #endif
480
481 #if MDB_DEBUG
482 static int mdb_debug;
483 static txnid_t mdb_debug_start;
484
485 /** Print a debug message with printf formatting.
486 * Requires double parenthesis around 2 or more args.
487 */
488 # define DPRINTF(args) ((void) ((mdb_debug) && DPRINTF0 args))
489 # define DPRINTF0(fmt, ...) \
490 fprintf(stderr, "%s:%d " fmt "\n", mdb_func_, __LINE__, __VA_ARGS__)
491 #else
492 # define DPRINTF(args) ((void) 0)
493 #endif
494 /** Print a debug string.
495 * The string is printed literally, with no format processing.
496 */
497 #define DPUTS(arg) DPRINTF(("%s", arg))
498 /** Debugging output value of a cursor DBI: Negative in a sub-cursor. */
499 #define DDBI(mc) \
500 (((mc)->mc_flags & C_SUB) ? -(int)(mc)->mc_dbi : (int)(mc)->mc_dbi)
501 /** @} */
502
503 /** @brief The maximum size of a database page.
504 *
505 * It is 32k or 64k, since value-PAGEBASE must fit in
506 * #MDB_page.%mp_upper.
507 *
508 * LMDB will use database pages < OS pages if needed.
509 * That causes more I/O in write transactions: The OS must
510 * know (read) the whole page before writing a partial page.
511 *
512 * Note that we don't currently support Huge pages. On Linux,
513 * regular data files cannot use Huge pages, and in general
514 * Huge pages aren't actually pageable. We rely on the OS
515 * demand-pager to read our data and page it out when memory
516 * pressure from other processes is high. So until OSs have
517 * actual paging support for Huge pages, they're not viable.
518 */
519 #define MAX_PAGESIZE (PAGEBASE ? 0x10000 : 0x8000)
520
521 /** The minimum number of keys required in a database page.
522 * Setting this to a larger value will place a smaller bound on the
523 * maximum size of a data item. Data items larger than this size will
524 * be pushed into overflow pages instead of being stored directly in
525 * the B-tree node. This value used to default to 4. With a page size
526 * of 4096 bytes that meant that any item larger than 1024 bytes would
527 * go into an overflow page. That also meant that on average 2-3KB of
528 * each overflow page was wasted space. The value cannot be lower than
529 * 2 because then there would no longer be a tree structure. With this
530 * value, items larger than 2KB will go into overflow pages, and on
531 * average only 1KB will be wasted.
532 */
533 #define MDB_MINKEYS 2
534
535 /** A stamp that identifies a file as an LMDB file.
536 * There's nothing special about this value other than that it is easily
537 * recognizable, and it will reflect any byte order mismatches.
538 */
539 #define MDB_MAGIC 0xBEEFC0DE
540
541 /** The version number for a database's datafile format. */
542 #define MDB_DATA_VERSION ((MDB_DEVEL) ? 999 : 1)
543 /** The version number for a database's lockfile format. */
544 #define MDB_LOCK_VERSION 1
545
546 /** @brief The max size of a key we can write, or 0 for computed max.
547 *
548 * This macro should normally be left alone or set to 0.
549 * Note that a database with big keys or dupsort data cannot be
550 * reliably modified by a liblmdb which uses a smaller max.
551 * The default is 511 for backwards compat, or 0 when #MDB_DEVEL.
552 *
553 * Other values are allowed, for backwards compat. However:
554 * A value bigger than the computed max can break if you do not
555 * know what you are doing, and liblmdb <= 0.9.10 can break when
556 * modifying a DB with keys/dupsort data bigger than its max.
557 *
558 * Data items in an #MDB_DUPSORT database are also limited to
559 * this size, since they're actually keys of a sub-DB. Keys and
560 * #MDB_DUPSORT data items must fit on a node in a regular page.
561 */
562 #ifndef MDB_MAXKEYSIZE
563 #define MDB_MAXKEYSIZE ((MDB_DEVEL) ? 0 : 511)
564 #endif
565
566 /** The maximum size of a key we can write to the environment. */
567 #if MDB_MAXKEYSIZE
568 #define ENV_MAXKEY(env) (MDB_MAXKEYSIZE)
569 #else
570 #define ENV_MAXKEY(env) ((env)->me_maxkey)
571 #endif
572
573 /** @brief The maximum size of a data item.
574 *
575 * We only store a 32 bit value for node sizes.
576 */
577 #define MAXDATASIZE 0xffffffffUL
578
579 #if MDB_DEBUG
580 /** Key size which fits in a #DKBUF.
581 * @ingroup debug
582 */
583 #define DKBUF_MAXKEYSIZE ((MDB_MAXKEYSIZE) > 0 ? (MDB_MAXKEYSIZE) : 511)
584 /** A key buffer.
585 * @ingroup debug
586 * This is used for printing a hex dump of a key's contents.
587 */
588 #define DKBUF char kbuf[DKBUF_MAXKEYSIZE*2+1]
589 /** Display a key in hex.
590 * @ingroup debug
591 * Invoke a function to display a key in hex.
592 */
593 #define DKEY(x) mdb_dkey(x, kbuf)
594 #else
595 #define DKBUF
596 #define DKEY(x) 0
597 #endif
598
599 /** An invalid page number.
600 * Mainly used to denote an empty tree.
601 */
602 #define P_INVALID (~(pgno_t)0)
603
604 /** Test if the flags \b f are set in a flag word \b w. */
605 #define F_ISSET(w, f) (((w) & (f)) == (f))
606
607 /** Round \b n up to an even number. */
608 #define EVEN(n) (((n) + 1U) & -2) /* sign-extending -2 to match n+1U */
609
610 /** Used for offsets within a single page.
611 * Since memory pages are typically 4 or 8KB in size, 12-13 bits,
612 * this is plenty.
613 */
614 typedef uint16_t indx_t;
615
616 /** Default size of memory map.
617 * This is certainly too small for any actual applications. Apps should always set
618 * the size explicitly using #mdb_env_set_mapsize().
619 */
620 #define DEFAULT_MAPSIZE 1048576
621
622 /** @defgroup readers Reader Lock Table
623 * Readers don't acquire any locks for their data access. Instead, they
624 * simply record their transaction ID in the reader table. The reader
625 * mutex is needed just to find an empty slot in the reader table. The
626 * slot's address is saved in thread-specific data so that subsequent read
627 * transactions started by the same thread need no further locking to proceed.
628 *
629 * If #MDB_NOTLS is set, the slot address is not saved in thread-specific data.
630 *
631 * No reader table is used if the database is on a read-only filesystem, or
632 * if #MDB_NOLOCK is set.
633 *
634 * Since the database uses multi-version concurrency control, readers don't
635 * actually need any locking. This table is used to keep track of which
636 * readers are using data from which old transactions, so that we'll know
637 * when a particular old transaction is no longer in use. Old transactions
638 * that have discarded any data pages can then have those pages reclaimed
639 * for use by a later write transaction.
640 *
641 * The lock table is constructed such that reader slots are aligned with the
642 * processor's cache line size. Any slot is only ever used by one thread.
643 * This alignment guarantees that there will be no contention or cache
644 * thrashing as threads update their own slot info, and also eliminates
645 * any need for locking when accessing a slot.
646 *
647 * A writer thread will scan every slot in the table to determine the oldest
648 * outstanding reader transaction. Any freed pages older than this will be
649 * reclaimed by the writer. The writer doesn't use any locks when scanning
650 * this table. This means that there's no guarantee that the writer will
651 * see the most up-to-date reader info, but that's not required for correct
652 * operation - all we need is to know the upper bound on the oldest reader,
653 * we don't care at all about the newest reader. So the only consequence of
654 * reading stale information here is that old pages might hang around a
655 * while longer before being reclaimed. That's actually good anyway, because
656 * the longer we delay reclaiming old pages, the more likely it is that a
657 * string of contiguous pages can be found after coalescing old pages from
658 * many old transactions together.
659 * @{
660 */
661 /** Number of slots in the reader table.
662 * This value was chosen somewhat arbitrarily. 126 readers plus a
663 * couple mutexes fit exactly into 8KB on my development machine.
664 * Applications should set the table size using #mdb_env_set_maxreaders().
665 */
666 #define DEFAULT_READERS 126
667
668 /** The size of a CPU cache line in bytes. We want our lock structures
669 * aligned to this size to avoid false cache line sharing in the
670 * lock table.
671 * This value works for most CPUs. For Itanium this should be 128.
672 */
673 #ifndef CACHELINE
674 #define CACHELINE 64
675 #endif
676
677 /** The information we store in a single slot of the reader table.
678 * In addition to a transaction ID, we also record the process and
679 * thread ID that owns a slot, so that we can detect stale information,
680 * e.g. threads or processes that went away without cleaning up.
681 * @note We currently don't check for stale records. We simply re-init
682 * the table when we know that we're the only process opening the
683 * lock file.
684 */
685 typedef struct MDB_rxbody {
686 /** Current Transaction ID when this transaction began, or (txnid_t)-1.
687 * Multiple readers that start at the same time will probably have the
688 * same ID here. Again, it's not important to exclude them from
689 * anything; all we need to know is which version of the DB they
690 * started from so we can avoid overwriting any data used in that
691 * particular version.
692 */
693 volatile txnid_t mrb_txnid;
694 /** The process ID of the process owning this reader txn. */
695 volatile MDB_PID_T mrb_pid;
696 /** The thread ID of the thread owning this txn. */
697 volatile MDB_THR_T mrb_tid;
698 } MDB_rxbody;
699
700 /** The actual reader record, with cacheline padding. */
701 typedef struct MDB_reader {
702 union {
703 MDB_rxbody mrx;
704 /** shorthand for mrb_txnid */
705 #define mr_txnid mru.mrx.mrb_txnid
706 #define mr_pid mru.mrx.mrb_pid
707 #define mr_tid mru.mrx.mrb_tid
708 /** cache line alignment */
709 char pad[(sizeof(MDB_rxbody)+CACHELINE-1) & ~(CACHELINE-1)];
710 } mru;
711 } MDB_reader;
712
713 /** The header for the reader table.
714 * The table resides in a memory-mapped file. (This is a different file
715 * than is used for the main database.)
716 *
717 * For POSIX the actual mutexes reside in the shared memory of this
718 * mapped file. On Windows, mutexes are named objects allocated by the
719 * kernel; we store the mutex names in this mapped file so that other
720 * processes can grab them. This same approach is also used on
721 * MacOSX/Darwin (using named semaphores) since MacOSX doesn't support
722 * process-shared POSIX mutexes. For these cases where a named object
723 * is used, the object name is derived from a 64 bit FNV hash of the
724 * environment pathname. As such, naming collisions are extremely
725 * unlikely. If a collision occurs, the results are unpredictable.
726 */
727 typedef struct MDB_txbody {
728 /** Stamp identifying this as an LMDB file. It must be set
729 * to #MDB_MAGIC. */
730 uint32_t mtb_magic;
731 /** Format of this lock file. Must be set to #MDB_LOCK_FORMAT. */
732 uint32_t mtb_format;
733 #if defined(_WIN32) || defined(MDB_USE_POSIX_SEM)
734 char mtb_rmname[MNAME_LEN];
735 #else
736 /** Mutex protecting access to this table.
737 * This is the reader table lock used with LOCK_MUTEX().
738 */
739 mdb_mutex_t mtb_rmutex;
740 #endif
741 /** The ID of the last transaction committed to the database.
742 * This is recorded here only for convenience; the value can always
743 * be determined by reading the main database meta pages.
744 */
745 volatile txnid_t mtb_txnid;
746 /** The number of slots that have been used in the reader table.
747 * This always records the maximum count, it is not decremented
748 * when readers release their slots.
749 */
750 volatile unsigned mtb_numreaders;
751 } MDB_txbody;
752
753 /** The actual reader table definition. */
754 typedef struct MDB_txninfo {
755 union {
756 MDB_txbody mtb;
757 #define mti_magic mt1.mtb.mtb_magic
758 #define mti_format mt1.mtb.mtb_format
759 #define mti_rmutex mt1.mtb.mtb_rmutex
760 #define mti_rmname mt1.mtb.mtb_rmname
761 #define mti_txnid mt1.mtb.mtb_txnid
762 #define mti_numreaders mt1.mtb.mtb_numreaders
763 char pad[(sizeof(MDB_txbody)+CACHELINE-1) & ~(CACHELINE-1)];
764 } mt1;
765 union {
766 #if defined(_WIN32) || defined(MDB_USE_POSIX_SEM)
767 char mt2_wmname[MNAME_LEN];
768 #define mti_wmname mt2.mt2_wmname
769 #else
770 mdb_mutex_t mt2_wmutex;
771 #define mti_wmutex mt2.mt2_wmutex
772 #endif
773 char pad[(MNAME_LEN+CACHELINE-1) & ~(CACHELINE-1)];
774 } mt2;
775 MDB_reader mti_readers[1];
776 } MDB_txninfo;
777
778 /** Lockfile format signature: version, features and field layout */
779 #define MDB_LOCK_FORMAT \
780 ((uint32_t) \
781 ((MDB_LOCK_VERSION) \
782 /* Flags which describe functionality */ \
783 + (((MDB_PIDLOCK) != 0) << 16)))
784 /** @} */
785
786 /** Common header for all page types. The page type depends on #mp_flags.
787 *
788 * #P_BRANCH and #P_LEAF pages have unsorted '#MDB_node's at the end, with
789 * sorted #mp_ptrs[] entries referring to them. Exception: #P_LEAF2 pages
790 * omit mp_ptrs and pack sorted #MDB_DUPFIXED values after the page header.
791 *
792 * #P_OVERFLOW records occupy one or more contiguous pages where only the
793 * first has a page header. They hold the real data of #F_BIGDATA nodes.
794 *
795 * #P_SUBP sub-pages are small leaf "pages" with duplicate data.
796 * A node with flag #F_DUPDATA but not #F_SUBDATA contains a sub-page.
797 * (Duplicate data can also go in sub-databases, which use normal pages.)
798 *
799 * #P_META pages contain #MDB_meta, the start point of an LMDB snapshot.
800 *
801 * Each non-metapage up to #MDB_meta.%mm_last_pg is reachable exactly once
802 * in the snapshot: Either used by a database or listed in a freeDB record.
803 */
804 typedef struct MDB_page {
805 #define mp_pgno mp_p.p_pgno
806 #define mp_next mp_p.p_next
807 union {
808 pgno_t p_pgno; /**< page number */
809 struct MDB_page *p_next; /**< for in-memory list of freed pages */
810 } mp_p;
811 uint16_t mp_pad; /**< key size if this is a LEAF2 page */
812 /** @defgroup mdb_page Page Flags
813 * @ingroup internal
814 * Flags for the page headers.
815 * @{
816 */
817 #define P_BRANCH 0x01 /**< branch page */
818 #define P_LEAF 0x02 /**< leaf page */
819 #define P_OVERFLOW 0x04 /**< overflow page */
820 #define P_META 0x08 /**< meta page */
821 #define P_DIRTY 0x10 /**< dirty page, also set for #P_SUBP pages */
822 #define P_LEAF2 0x20 /**< for #MDB_DUPFIXED records */
823 #define P_SUBP 0x40 /**< for #MDB_DUPSORT sub-pages */
824 #define P_LOOSE 0x4000 /**< page was dirtied then freed, can be reused */
825 #define P_KEEP 0x8000 /**< leave this page alone during spill */
826 /** @} */
827 uint16_t mp_flags; /**< @ref mdb_page */
828 #define mp_lower mp_pb.pb.pb_lower
829 #define mp_upper mp_pb.pb.pb_upper
830 #define mp_pages mp_pb.pb_pages
831 union {
832 struct {
833 indx_t pb_lower; /**< lower bound of free space */
834 indx_t pb_upper; /**< upper bound of free space */
835 } pb;
836 uint32_t pb_pages; /**< number of overflow pages */
837 } mp_pb;
838 indx_t mp_ptrs[1]; /**< dynamic size */
839 } MDB_page;
840
841 /** Size of the page header, excluding dynamic data at the end */
842 #define PAGEHDRSZ ((unsigned) offsetof(MDB_page, mp_ptrs))
843
844 /** Address of first usable data byte in a page, after the header */
845 #define METADATA(p) ((void *)((char *)(p) + PAGEHDRSZ))
846
847 /** ITS#7713, change PAGEBASE to handle 65536 byte pages */
848 #define PAGEBASE ((MDB_DEVEL) ? PAGEHDRSZ : 0)
849
850 /** Number of nodes on a page */
851 #define NUMKEYS(p) (((p)->mp_lower - (PAGEHDRSZ-PAGEBASE)) >> 1)
852
853 /** The amount of space remaining in the page */
854 #define SIZELEFT(p) (indx_t)((p)->mp_upper - (p)->mp_lower)
855
856 /** The percentage of space used in the page, in tenths of a percent. */
857 #define PAGEFILL(env, p) (1000L * ((env)->me_psize - PAGEHDRSZ - SIZELEFT(p)) / \
858 ((env)->me_psize - PAGEHDRSZ))
859 /** The minimum page fill factor, in tenths of a percent.
860 * Pages emptier than this are candidates for merging.
861 */
862 #define FILL_THRESHOLD 250
863
864 /** Test if a page is a leaf page */
865 #define IS_LEAF(p) F_ISSET((p)->mp_flags, P_LEAF)
866 /** Test if a page is a LEAF2 page */
867 #define IS_LEAF2(p) F_ISSET((p)->mp_flags, P_LEAF2)
868 /** Test if a page is a branch page */
869 #define IS_BRANCH(p) F_ISSET((p)->mp_flags, P_BRANCH)
870 /** Test if a page is an overflow page */
871 #define IS_OVERFLOW(p) F_ISSET((p)->mp_flags, P_OVERFLOW)
872 /** Test if a page is a sub page */
873 #define IS_SUBP(p) F_ISSET((p)->mp_flags, P_SUBP)
874
875 /** The number of overflow pages needed to store the given size. */
876 #define OVPAGES(size, psize) ((PAGEHDRSZ-1 + (size)) / (psize) + 1)
877
878 /** Link in #MDB_txn.%mt_loose_pgs list.
879 * Kept outside the page header, which is needed when reusing the page.
880 */
881 #define NEXT_LOOSE_PAGE(p) (*(MDB_page **)((p) + 2))
882
883 /** Header for a single key/data pair within a page.
884 * Used in pages of type #P_BRANCH and #P_LEAF without #P_LEAF2.
885 * We guarantee 2-byte alignment for 'MDB_node's.
886 *
887 * #mn_lo and #mn_hi are used for data size on leaf nodes, and for child
888 * pgno on branch nodes. On 64 bit platforms, #mn_flags is also used
889 * for pgno. (Branch nodes have no flags). Lo and hi are in host byte
890 * order in case some accesses can be optimized to 32-bit word access.
891 *
892 * Leaf node flags describe node contents. #F_BIGDATA says the node's
893 * data part is the page number of an overflow page with actual data.
894 * #F_DUPDATA and #F_SUBDATA can be combined giving duplicate data in
895 * a sub-page/sub-database, and named databases (just #F_SUBDATA).
896 */
897 typedef struct MDB_node {
898 /** part of data size or pgno
899 * @{ */
900 #if BYTE_ORDER == LITTLE_ENDIAN
901 unsigned short mn_lo, mn_hi;
902 #else
903 unsigned short mn_hi, mn_lo;
904 #endif
905 /** @} */
906 /** @defgroup mdb_node Node Flags
907 * @ingroup internal
908 * Flags for node headers.
909 * @{
910 */
911 #define F_BIGDATA 0x01 /**< data put on overflow page */
912 #define F_SUBDATA 0x02 /**< data is a sub-database */
913 #define F_DUPDATA 0x04 /**< data has duplicates */
914
915 /** valid flags for #mdb_node_add() */
916 #define NODE_ADD_FLAGS (F_DUPDATA|F_SUBDATA|MDB_RESERVE|MDB_APPEND)
917
918 /** @} */
919 unsigned short mn_flags; /**< @ref mdb_node */
920 unsigned short mn_ksize; /**< key size */
921 char mn_data[1]; /**< key and data are appended here */
922 } MDB_node;
923
924 /** Size of the node header, excluding dynamic data at the end */
925 #define NODESIZE offsetof(MDB_node, mn_data)
926
927 /** Bit position of top word in page number, for shifting mn_flags */
928 #define PGNO_TOPWORD ((pgno_t)-1 > 0xffffffffu ? 32 : 0)
929
930 /** Size of a node in a branch page with a given key.
931 * This is just the node header plus the key, there is no data.
932 */
933 #define INDXSIZE(k) (NODESIZE + ((k) == NULL ? 0 : (k)->mv_size))
934
935 /** Size of a node in a leaf page with a given key and data.
936 * This is node header plus key plus data size.
937 */
938 #define LEAFSIZE(k, d) (NODESIZE + (k)->mv_size + (d)->mv_size)
939
940 /** Address of node \b i in page \b p */
941 #define NODEPTR(p, i) ((MDB_node *)((char *)(p) + (p)->mp_ptrs[i] + PAGEBASE))
942
943 /** Address of the key for the node */
944 #define NODEKEY(node) (void *)((node)->mn_data)
945
946 /** Address of the data for a node */
947 #define NODEDATA(node) (void *)((char *)(node)->mn_data + (node)->mn_ksize)
948
949 /** Get the page number pointed to by a branch node */
950 #define NODEPGNO(node) \
951 ((node)->mn_lo | ((pgno_t) (node)->mn_hi << 16) | \
952 (PGNO_TOPWORD ? ((pgno_t) (node)->mn_flags << PGNO_TOPWORD) : 0))
953 /** Set the page number in a branch node */
954 #define SETPGNO(node,pgno) do { \
955 (node)->mn_lo = (pgno) & 0xffff; (node)->mn_hi = (pgno) >> 16; \
956 if (PGNO_TOPWORD) (node)->mn_flags = (pgno) >> PGNO_TOPWORD; } while(0)
957
958 /** Get the size of the data in a leaf node */
959 #define NODEDSZ(node) ((node)->mn_lo | ((unsigned)(node)->mn_hi << 16))
960 /** Set the size of the data for a leaf node */
961 #define SETDSZ(node,size) do { \
962 (node)->mn_lo = (size) & 0xffff; (node)->mn_hi = (size) >> 16;} while(0)
963 /** The size of a key in a node */
964 #define NODEKSZ(node) ((node)->mn_ksize)
965
966 /** Copy a page number from src to dst */
967 #ifdef MISALIGNED_OK
968 #define COPY_PGNO(dst,src) dst = src
969 #else
970 #if SIZE_MAX > 4294967295UL
971 #define COPY_PGNO(dst,src) do { \
972 unsigned short *s, *d; \
973 s = (unsigned short *)&(src); \
974 d = (unsigned short *)&(dst); \
975 *d++ = *s++; \
976 *d++ = *s++; \
977 *d++ = *s++; \
978 *d = *s; \
979 } while (0)
980 #else
981 #define COPY_PGNO(dst,src) do { \
982 unsigned short *s, *d; \
983 s = (unsigned short *)&(src); \
984 d = (unsigned short *)&(dst); \
985 *d++ = *s++; \
986 *d = *s; \
987 } while (0)
988 #endif
989 #endif
990 /** The address of a key in a LEAF2 page.
991 * LEAF2 pages are used for #MDB_DUPFIXED sorted-duplicate sub-DBs.
992 * There are no node headers, keys are stored contiguously.
993 */
994 #define LEAF2KEY(p, i, ks) ((char *)(p) + PAGEHDRSZ + ((i)*(ks)))
995
996 /** Set the \b node's key into \b keyptr, if requested. */
997 #define MDB_GET_KEY(node, keyptr) { if ((keyptr) != NULL) { \
998 (keyptr)->mv_size = NODEKSZ(node); (keyptr)->mv_data = NODEKEY(node); } }
999
1000 /** Set the \b node's key into \b key. */
1001 #define MDB_GET_KEY2(node, key) { key.mv_size = NODEKSZ(node); key.mv_data = NODEKEY(node); }
1002
1003 /** Information about a single database in the environment. */
1004 typedef struct MDB_db {
1005 uint32_t md_pad; /**< also ksize for LEAF2 pages */
1006 uint16_t md_flags; /**< @ref mdb_dbi_open */
1007 uint16_t md_depth; /**< depth of this tree */
1008 pgno_t md_branch_pages; /**< number of internal pages */
1009 pgno_t md_leaf_pages; /**< number of leaf pages */
1010 pgno_t md_overflow_pages; /**< number of overflow pages */
1011 size_t md_entries; /**< number of data items */
1012 pgno_t md_root; /**< the root page of this tree */
1013 } MDB_db;
1014
1015 #define MDB_VALID 0x8000 /**< DB handle is valid, for me_dbflags */
1016 #define PERSISTENT_FLAGS (0xffff & ~(MDB_VALID))
1017 /** #mdb_dbi_open() flags */
1018 #define VALID_FLAGS (MDB_REVERSEKEY|MDB_DUPSORT|MDB_INTEGERKEY|MDB_DUPFIXED|\
1019 MDB_INTEGERDUP|MDB_REVERSEDUP|MDB_CREATE)
1020
1021 /** Handle for the DB used to track free pages. */
1022 #define FREE_DBI 0
1023 /** Handle for the default DB. */
1024 #define MAIN_DBI 1
1025 /** Number of DBs in metapage (free and main) - also hardcoded elsewhere */
1026 #define CORE_DBS 2
1027
1028 /** Number of meta pages - also hardcoded elsewhere */
1029 #define NUM_METAS 2
1030
1031 /** Meta page content.
1032 * A meta page is the start point for accessing a database snapshot.
1033 * Pages 0-1 are meta pages. Transaction N writes meta page #(N % 2).
1034 */
1035 typedef struct MDB_meta {
1036 /** Stamp identifying this as an LMDB file. It must be set
1037 * to #MDB_MAGIC. */
1038 uint32_t mm_magic;
1039 /** Version number of this file. Must be set to #MDB_DATA_VERSION. */
1040 uint32_t mm_version;
1041 void *mm_address; /**< address for fixed mapping */
1042 size_t mm_mapsize; /**< size of mmap region */
1043 MDB_db mm_dbs[CORE_DBS]; /**< first is free space, 2nd is main db */
1044 /** The size of pages used in this DB */
1045 #define mm_psize mm_dbs[FREE_DBI].md_pad
1046 /** Any persistent environment flags. @ref mdb_env */
1047 #define mm_flags mm_dbs[FREE_DBI].md_flags
1048 /** Last used page in the datafile.
1049 * Actually the file may be shorter if the freeDB lists the final pages.
1050 */
1051 pgno_t mm_last_pg;
1052 volatile txnid_t mm_txnid; /**< txnid that committed this page */
1053 } MDB_meta;
1054
1055 /** Buffer for a stack-allocated meta page.
1056 * The members define size and alignment, and silence type
1057 * aliasing warnings. They are not used directly; that could
1058 * mean incorrectly using several union members in parallel.
1059 */
1060 typedef union MDB_metabuf {
1061 MDB_page mb_page;
1062 struct {
1063 char mm_pad[PAGEHDRSZ];
1064 MDB_meta mm_meta;
1065 } mb_metabuf;
1066 } MDB_metabuf;
1067
1068 /** Auxiliary DB info.
1069 * The information here is mostly static/read-only. There is
1070 * only a single copy of this record in the environment.
1071 */
1072 typedef struct MDB_dbx {
1073 MDB_val md_name; /**< name of the database */
1074 MDB_cmp_func *md_cmp; /**< function for comparing keys */
1075 MDB_cmp_func *md_dcmp; /**< function for comparing data items */
1076 MDB_rel_func *md_rel; /**< user relocate function */
1077 void *md_relctx; /**< user-provided context for md_rel */
1078 } MDB_dbx;
1079
1080 /** A database transaction.
1081 * Every operation requires a transaction handle.
1082 */
1083 struct MDB_txn {
1084 MDB_txn *mt_parent; /**< parent of a nested txn */
1085 /** Nested txn under this txn, set together with flag #MDB_TXN_HAS_CHILD */
1086 MDB_txn *mt_child;
1087 pgno_t mt_next_pgno; /**< next unallocated page */
1088 /** The ID of this transaction. IDs are integers incrementing from 1.
1089 * Only committed write transactions increment the ID. If a transaction
1090 * aborts, the ID may be re-used by the next writer.
1091 */
1092 txnid_t mt_txnid;
1093 MDB_env *mt_env; /**< the DB environment */
1094 /** The list of pages that became unused during this transaction.
1095 */
1096 MDB_IDL mt_free_pgs;
1097 /** The list of loose pages that became unused and may be reused
1098 * in this transaction, linked through #NEXT_LOOSE_PAGE(page).
1099 */
1100 MDB_page *mt_loose_pgs;
1101 /** Number of loose pages (#mt_loose_pgs) */
1102 int mt_loose_count;
1103 /** The sorted list of dirty pages we temporarily wrote to disk
1104 * because the dirty list was full. page numbers in here are
1105 * shifted left by 1, deleted slots have the LSB set.
1106 */
1107 MDB_IDL mt_spill_pgs;
1108 union {
1109 /** For write txns: Modified pages. Sorted when not MDB_WRITEMAP. */
1110 MDB_ID2L dirty_list;
1111 /** For read txns: This thread/txn's reader table slot, or NULL. */
1112 MDB_reader *reader;
1113 } mt_u;
1114 /** Array of records for each DB known in the environment. */
1115 MDB_dbx *mt_dbxs;
1116 /** Array of MDB_db records for each known DB */
1117 MDB_db *mt_dbs;
1118 /** Array of sequence numbers for each DB handle */
1119 unsigned int *mt_dbiseqs;
1120 /** @defgroup mt_dbflag Transaction DB Flags
1121 * @ingroup internal
1122 * @{
1123 */
1124 #define DB_DIRTY 0x01 /**< DB was written in this txn */
1125 #define DB_STALE 0x02 /**< Named-DB record is older than txnID */
1126 #define DB_NEW 0x04 /**< Named-DB handle opened in this txn */
1127 #define DB_VALID 0x08 /**< DB handle is valid, see also #MDB_VALID */
1128 #define DB_USRVALID 0x10 /**< As #DB_VALID, but not set for #FREE_DBI */
1129 #define DB_DUPDATA 0x20 /**< DB is #MDB_DUPSORT data */
1130 /** @} */
1131 /** In write txns, array of cursors for each DB */
1132 MDB_cursor **mt_cursors;
1133 /** Array of flags for each DB */
1134 unsigned char *mt_dbflags;
1135 /** Number of DB records in use, or 0 when the txn is finished.
1136 * This number only ever increments until the txn finishes; we
1137 * don't decrement it when individual DB handles are closed.
1138 */
1139 MDB_dbi mt_numdbs;
1140
1141 /** @defgroup mdb_txn Transaction Flags
1142 * @ingroup internal
1143 * @{
1144 */
1145 /** #mdb_txn_begin() flags */
1146 #define MDB_TXN_BEGIN_FLAGS MDB_RDONLY
1147 #define MDB_TXN_RDONLY MDB_RDONLY /**< read-only transaction */
1148 /* internal txn flags */
1149 #define MDB_TXN_WRITEMAP MDB_WRITEMAP /**< copy of #MDB_env flag in writers */
1150 #define MDB_TXN_FINISHED 0x01 /**< txn is finished or never began */
1151 #define MDB_TXN_ERROR 0x02 /**< txn is unusable after an error */
1152 #define MDB_TXN_DIRTY 0x04 /**< must write, even if dirty list is empty */
1153 #define MDB_TXN_SPILLS 0x08 /**< txn or a parent has spilled pages */
1154 #define MDB_TXN_HAS_CHILD 0x10 /**< txn has an #MDB_txn.%mt_child */
1155 /** most operations on the txn are currently illegal */
1156 #define MDB_TXN_BLOCKED (MDB_TXN_FINISHED|MDB_TXN_ERROR|MDB_TXN_HAS_CHILD)
1157 /** @} */
1158 unsigned int mt_flags; /**< @ref mdb_txn */
1159 /** #dirty_list room: Array size - \#dirty pages visible to this txn.
1160 * Includes ancestor txns' dirty pages not hidden by other txns'
1161 * dirty/spilled pages. Thus commit(nested txn) has room to merge
1162 * dirty_list into mt_parent after freeing hidden mt_parent pages.
1163 */
1164 unsigned int mt_dirty_room;
1165 };
1166
1167 /** Enough space for 2^32 nodes with minimum of 2 keys per node. I.e., plenty.
1168 * At 4 keys per node, enough for 2^64 nodes, so there's probably no need to
1169 * raise this on a 64 bit machine.
1170 */
1171 #define CURSOR_STACK 32
1172
1173 struct MDB_xcursor;
1174
1175 /** Cursors are used for all DB operations.
1176 * A cursor holds a path of (page pointer, key index) from the DB
1177 * root to a position in the DB, plus other state. #MDB_DUPSORT
1178 * cursors include an xcursor to the current data item. Write txns
1179 * track their cursors and keep them up to date when data moves.
1180 * Exception: An xcursor's pointer to a #P_SUBP page can be stale.
1181 * (A node with #F_DUPDATA but no #F_SUBDATA contains a subpage).
1182 */
1183 struct MDB_cursor {
1184 /** Next cursor on this DB in this txn */
1185 MDB_cursor *mc_next;
1186 /** Backup of the original cursor if this cursor is a shadow */
1187 MDB_cursor *mc_backup;
1188 /** Context used for databases with #MDB_DUPSORT, otherwise NULL */
1189 struct MDB_xcursor *mc_xcursor;
1190 /** The transaction that owns this cursor */
1191 MDB_txn *mc_txn;
1192 /** The database handle this cursor operates on */
1193 MDB_dbi mc_dbi;
1194 /** The database record for this cursor */
1195 MDB_db *mc_db;
1196 /** The database auxiliary record for this cursor */
1197 MDB_dbx *mc_dbx;
1198 /** The @ref mt_dbflag for this database */
1199 unsigned char *mc_dbflag;
1200 unsigned short mc_snum; /**< number of pushed pages */
1201 unsigned short mc_top; /**< index of top page, normally mc_snum-1 */
1202 /** @defgroup mdb_cursor Cursor Flags
1203 * @ingroup internal
1204 * Cursor state flags.
1205 * @{
1206 */
1207 #define C_INITIALIZED 0x01 /**< cursor has been initialized and is valid */
1208 #define C_EOF 0x02 /**< No more data */
1209 #define C_SUB 0x04 /**< Cursor is a sub-cursor */
1210 #define C_DEL 0x08 /**< last op was a cursor_del */
1211 #define C_UNTRACK 0x40 /**< Un-track cursor when closing */
1212 /** @} */
1213 unsigned int mc_flags; /**< @ref mdb_cursor */
1214 MDB_page *mc_pg[CURSOR_STACK]; /**< stack of pushed pages */
1215 indx_t mc_ki[CURSOR_STACK]; /**< stack of page indices */
1216 };
1217
1218 /** Context for sorted-dup records.
1219 * We could have gone to a fully recursive design, with arbitrarily
1220 * deep nesting of sub-databases. But for now we only handle these
1221 * levels - main DB, optional sub-DB, sorted-duplicate DB.
1222 */
1223 typedef struct MDB_xcursor {
1224 /** A sub-cursor for traversing the Dup DB */
1225 MDB_cursor mx_cursor;
1226 /** The database record for this Dup DB */
1227 MDB_db mx_db;
1228 /** The auxiliary DB record for this Dup DB */
1229 MDB_dbx mx_dbx;
1230 /** The @ref mt_dbflag for this Dup DB */
1231 unsigned char mx_dbflag;
1232 } MDB_xcursor;
1233
1234 /** Check if there is an inited xcursor */
1235 #define XCURSOR_INITED(mc) \
1236 ((mc)->mc_xcursor && ((mc)->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED))
1237
1238 /** Update the xcursor's sub-page pointer, if any, in \b mc. Needed
1239 * when the node which contains the sub-page may have moved. Called
1240 * with leaf page \b mp = mc->mc_pg[\b top].
1241 */
1242 #define XCURSOR_REFRESH(mc, top, mp) do { \
1243 MDB_page *xr_pg = (mp); \
1244 MDB_node *xr_node; \
1245 if (!XCURSOR_INITED(mc) || (mc)->mc_ki[top] >= NUMKEYS(xr_pg)) break; \
1246 xr_node = NODEPTR(xr_pg, (mc)->mc_ki[top]); \
1247 if ((xr_node->mn_flags & (F_DUPDATA|F_SUBDATA)) == F_DUPDATA) \
1248 (mc)->mc_xcursor->mx_cursor.mc_pg[0] = NODEDATA(xr_node); \
1249 } while (0)
1250
1251 /** State of FreeDB old pages, stored in the MDB_env */
1252 typedef struct MDB_pgstate {
1253 pgno_t *mf_pghead; /**< Reclaimed freeDB pages, or NULL before use */
1254 txnid_t mf_pglast; /**< ID of last used record, or 0 if !mf_pghead */
1255 } MDB_pgstate;
1256
1257 /** The database environment. */
1258 struct MDB_env {
1259 HANDLE me_fd; /**< The main data file */
1260 HANDLE me_lfd; /**< The lock file */
1261 HANDLE me_mfd; /**< For writing and syncing the meta pages */
1262 /** Failed to update the meta page. Probably an I/O error. */
1263 #define MDB_FATAL_ERROR 0x80000000U
1264 /** Some fields are initialized. */
1265 #define MDB_ENV_ACTIVE 0x20000000U
1266 /** me_txkey is set */
1267 #define MDB_ENV_TXKEY 0x10000000U
1268 /** fdatasync is unreliable */
1269 #define MDB_FSYNCONLY 0x08000000U
1270 uint32_t me_flags; /**< @ref mdb_env */
1271 unsigned int me_psize; /**< DB page size, inited from me_os_psize */
1272 unsigned int me_os_psize; /**< OS page size, from #GET_PAGESIZE */
1273 unsigned int me_maxreaders; /**< size of the reader table */
1274 /** Max #MDB_txninfo.%mti_numreaders of interest to #mdb_env_close() */
1275 volatile int me_close_readers;
1276 MDB_dbi me_numdbs; /**< number of DBs opened */
1277 MDB_dbi me_maxdbs; /**< size of the DB table */
1278 MDB_PID_T me_pid; /**< process ID of this env */
1279 char *me_path; /**< path to the DB files */
1280 char *me_map; /**< the memory map of the data file */
1281 MDB_txninfo *me_txns; /**< the memory map of the lock file or NULL */
1282 MDB_meta *me_metas[NUM_METAS]; /**< pointers to the two meta pages */
1283 void *me_pbuf; /**< scratch area for DUPSORT put() */
1284 MDB_txn *me_txn; /**< current write transaction */
1285 MDB_txn *me_txn0; /**< prealloc'd write transaction */
1286 size_t me_mapsize; /**< size of the data memory map */
1287 off_t me_size; /**< current file size */
1288 pgno_t me_maxpg; /**< me_mapsize / me_psize */
1289 MDB_dbx *me_dbxs; /**< array of static DB info */
1290 uint16_t *me_dbflags; /**< array of flags from MDB_db.md_flags */
1291 unsigned int *me_dbiseqs; /**< array of dbi sequence numbers */
1292 pthread_key_t me_txkey; /**< thread-key for readers */
1293 txnid_t me_pgoldest; /**< ID of oldest reader last time we looked */
1294 MDB_pgstate me_pgstate; /**< state of old pages from freeDB */
1295 # define me_pglast me_pgstate.mf_pglast
1296 # define me_pghead me_pgstate.mf_pghead
1297 MDB_page *me_dpages; /**< list of malloc'd blocks for re-use */
1298 /** IDL of pages that became unused in a write txn */
1299 MDB_IDL me_free_pgs;
1300 /** ID2L of pages written during a write txn. Length MDB_IDL_UM_SIZE. */
1301 MDB_ID2L me_dirty_list;
1302 /** Max number of freelist items that can fit in a single overflow page */
1303 int me_maxfree_1pg;
1304 /** Max size of a node on a page */
1305 unsigned int me_nodemax;
1306 #if !(MDB_MAXKEYSIZE)
1307 unsigned int me_maxkey; /**< max size of a key */
1308 #endif
1309 int me_live_reader; /**< have liveness lock in reader table */
1310 #ifdef _WIN32
1311 int me_pidquery; /**< Used in OpenProcess */
1312 #endif
1313 #ifdef MDB_USE_POSIX_MUTEX /* Posix mutexes reside in shared mem */
1314 # define me_rmutex me_txns->mti_rmutex /**< Shared reader lock */
1315 # define me_wmutex me_txns->mti_wmutex /**< Shared writer lock */
1316 #else
1317 mdb_mutex_t me_rmutex;
1318 mdb_mutex_t me_wmutex;
1319 #endif
1320 void *me_userctx; /**< User-settable context */
1321 MDB_assert_func *me_assert_func; /**< Callback for assertion failures */
1322 };
1323
1324 /** Nested transaction */
1325 typedef struct MDB_ntxn {
1326 MDB_txn mnt_txn; /**< the transaction */
1327 MDB_pgstate mnt_pgstate; /**< parent transaction's saved freestate */
1328 } MDB_ntxn;
1329
1330 /** max number of pages to commit in one writev() call */
1331 #define MDB_COMMIT_PAGES 64
1332 #if defined(IOV_MAX) && IOV_MAX < MDB_COMMIT_PAGES
1333 #undef MDB_COMMIT_PAGES
1334 #define MDB_COMMIT_PAGES IOV_MAX
1335 #endif
1336
1337 /** max bytes to write in one call */
1338 #define MAX_WRITE (0x40000000U >> (sizeof(ssize_t) == 4))
1339
1340 /** Check \b txn and \b dbi arguments to a function */
1341 #define TXN_DBI_EXIST(txn, dbi, validity) \
1342 ((txn) && (dbi)<(txn)->mt_numdbs && ((txn)->mt_dbflags[dbi] & (validity)))
1343
1344 /** Check for misused \b dbi handles */
1345 #define TXN_DBI_CHANGED(txn, dbi) \
1346 ((txn)->mt_dbiseqs[dbi] != (txn)->mt_env->me_dbiseqs[dbi])
1347
1348 static int mdb_page_alloc(MDB_cursor *mc, int num, MDB_page **mp);
1349 static int mdb_page_new(MDB_cursor *mc, uint32_t flags, int num, MDB_page **mp);
1350 static int mdb_page_touch(MDB_cursor *mc);
1351
1352 #define MDB_END_NAMES {"committed", "empty-commit", "abort", "reset", \
1353 "reset-tmp", "fail-begin", "fail-beginchild"}
1354 enum {
1355 /* mdb_txn_end operation number, for logging */
1356 MDB_END_COMMITTED, MDB_END_EMPTY_COMMIT, MDB_END_ABORT, MDB_END_RESET,
1357 MDB_END_RESET_TMP, MDB_END_FAIL_BEGIN, MDB_END_FAIL_BEGINCHILD
1358 };
1359 #define MDB_END_OPMASK 0x0F /**< mask for #mdb_txn_end() operation number */
1360 #define MDB_END_UPDATE 0x10 /**< update env state (DBIs) */
1361 #define MDB_END_FREE 0x20 /**< free txn unless it is #MDB_env.%me_txn0 */
1362 #define MDB_END_SLOT MDB_NOTLS /**< release any reader slot if #MDB_NOTLS */
1363 static void mdb_txn_end(MDB_txn *txn, unsigned mode);
1364
1365 static int mdb_page_get(MDB_cursor *mc, pgno_t pgno, MDB_page **mp, int *lvl);
1366 static int mdb_page_search_root(MDB_cursor *mc,
1367 MDB_val *key, int modify);
1368 #define MDB_PS_MODIFY 1
1369 #define MDB_PS_ROOTONLY 2
1370 #define MDB_PS_FIRST 4
1371 #define MDB_PS_LAST 8
1372 static int mdb_page_search(MDB_cursor *mc,
1373 MDB_val *key, int flags);
1374 static int mdb_page_merge(MDB_cursor *csrc, MDB_cursor *cdst);
1375
1376 #define MDB_SPLIT_REPLACE MDB_APPENDDUP /**< newkey is not new */
1377 static int mdb_page_split(MDB_cursor *mc, MDB_val *newkey, MDB_val *newdata,
1378 pgno_t newpgno, unsigned int nflags);
1379
1380 static int mdb_env_read_header(MDB_env *env, MDB_meta *meta);
1381 static MDB_meta *mdb_env_pick_meta(const MDB_env *env);
1382 static int mdb_env_write_meta(MDB_txn *txn);
1383 #if defined(MDB_USE_POSIX_MUTEX) && !defined(MDB_ROBUST_SUPPORTED) /* Drop unused excl arg */
1384 # define mdb_env_close0(env, excl) mdb_env_close1(env)
1385 #endif
1386 static void mdb_env_close0(MDB_env *env, int excl);
1387
1388 static MDB_node *mdb_node_search(MDB_cursor *mc, MDB_val *key, int *exactp);
1389 static int mdb_node_add(MDB_cursor *mc, indx_t indx,
1390 MDB_val *key, MDB_val *data, pgno_t pgno, unsigned int flags);
1391 static void mdb_node_del(MDB_cursor *mc, int ksize);
1392 static void mdb_node_shrink(MDB_page *mp, indx_t indx);
1393 static int mdb_node_move(MDB_cursor *csrc, MDB_cursor *cdst, int fromleft);
1394 static int mdb_node_read(MDB_cursor *mc, MDB_node *leaf, MDB_val *data);
1395 static size_t mdb_leaf_size(MDB_env *env, MDB_val *key, MDB_val *data);
1396 static size_t mdb_branch_size(MDB_env *env, MDB_val *key);
1397
1398 static int mdb_rebalance(MDB_cursor *mc);
1399 static int mdb_update_key(MDB_cursor *mc, MDB_val *key);
1400
1401 static void mdb_cursor_pop(MDB_cursor *mc);
1402 static int mdb_cursor_push(MDB_cursor *mc, MDB_page *mp);
1403
1404 static int mdb_cursor_del0(MDB_cursor *mc);
1405 static int mdb_del0(MDB_txn *txn, MDB_dbi dbi, MDB_val *key, MDB_val *data, unsigned flags);
1406 static int mdb_cursor_sibling(MDB_cursor *mc, int move_right);
1407 static int mdb_cursor_next(MDB_cursor *mc, MDB_val *key, MDB_val *data, MDB_cursor_op op);
1408 static int mdb_cursor_prev(MDB_cursor *mc, MDB_val *key, MDB_val *data, MDB_cursor_op op);
1409 static int mdb_cursor_set(MDB_cursor *mc, MDB_val *key, MDB_val *data, MDB_cursor_op op,
1410 int *exactp);
1411 static int mdb_cursor_first(MDB_cursor *mc, MDB_val *key, MDB_val *data);
1412 static int mdb_cursor_last(MDB_cursor *mc, MDB_val *key, MDB_val *data);
1413
1414 static void mdb_cursor_init(MDB_cursor *mc, MDB_txn *txn, MDB_dbi dbi, MDB_xcursor *mx);
1415 static void mdb_xcursor_init0(MDB_cursor *mc);
1416 static void mdb_xcursor_init1(MDB_cursor *mc, MDB_node *node);
1417 static void mdb_xcursor_init2(MDB_cursor *mc, MDB_xcursor *src_mx, int force);
1418
1419 static int mdb_drop0(MDB_cursor *mc, int subs);
1420 static void mdb_default_cmp(MDB_txn *txn, MDB_dbi dbi);
1421 static int mdb_reader_check0(MDB_env *env, int rlocked, int *dead);
1422
1423 /** @cond */
1424 static MDB_cmp_func mdb_cmp_memn, mdb_cmp_memnr, mdb_cmp_int, mdb_cmp_cint, mdb_cmp_long;
1425 /** @endcond */
1426
1427 /** Compare two items pointing at size_t's of unknown alignment. */
1428 #ifdef MISALIGNED_OK
1429 # define mdb_cmp_clong mdb_cmp_long
1430 #else
1431 # define mdb_cmp_clong mdb_cmp_cint
1432 #endif
1433
1434 #ifdef _WIN32
1435 static SECURITY_DESCRIPTOR mdb_null_sd;
1436 static SECURITY_ATTRIBUTES mdb_all_sa;
1437 static int mdb_sec_inited;
1438
1439 struct MDB_name;
1440 static int utf8_to_utf16(const char *src, struct MDB_name *dst, int xtra);
1441 #endif
1442
1443 /** Return the library version info. */
1444 char * ESECT
mdb_version(int * major,int * minor,int * patch)1445 mdb_version(int *major, int *minor, int *patch)
1446 {
1447 if (major) *major = MDB_VERSION_MAJOR;
1448 if (minor) *minor = MDB_VERSION_MINOR;
1449 if (patch) *patch = MDB_VERSION_PATCH;
1450 return MDB_VERSION_STRING;
1451 }
1452
1453 /** Table of descriptions for LMDB @ref errors */
1454 static char *const mdb_errstr[] = {
1455 "MDB_KEYEXIST: Key/data pair already exists",
1456 "MDB_NOTFOUND: No matching key/data pair found",
1457 "MDB_PAGE_NOTFOUND: Requested page not found",
1458 "MDB_CORRUPTED: Located page was wrong type",
1459 "MDB_PANIC: Update of meta page failed or environment had fatal error",
1460 "MDB_VERSION_MISMATCH: Database environment version mismatch",
1461 "MDB_INVALID: File is not an LMDB file",
1462 "MDB_MAP_FULL: Environment mapsize limit reached",
1463 "MDB_DBS_FULL: Environment maxdbs limit reached",
1464 "MDB_READERS_FULL: Environment maxreaders limit reached",
1465 "MDB_TLS_FULL: Thread-local storage keys full - too many environments open",
1466 "MDB_TXN_FULL: Transaction has too many dirty pages - transaction too big",
1467 "MDB_CURSOR_FULL: Internal error - cursor stack limit reached",
1468 "MDB_PAGE_FULL: Internal error - page has no more space",
1469 "MDB_MAP_RESIZED: Database contents grew beyond environment mapsize",
1470 "MDB_INCOMPATIBLE: Operation and DB incompatible, or DB flags changed",
1471 "MDB_BAD_RSLOT: Invalid reuse of reader locktable slot",
1472 "MDB_BAD_TXN: Transaction must abort, has a child, or is invalid",
1473 "MDB_BAD_VALSIZE: Unsupported size of key/DB name/data, or wrong DUPFIXED size",
1474 "MDB_BAD_DBI: The specified DBI handle was closed/changed unexpectedly",
1475 };
1476
1477 char *
mdb_strerror(int err)1478 mdb_strerror(int err)
1479 {
1480 #ifdef _WIN32
1481 /** HACK: pad 4KB on stack over the buf. Return system msgs in buf.
1482 * This works as long as no function between the call to mdb_strerror
1483 * and the actual use of the message uses more than 4K of stack.
1484 */
1485 #define MSGSIZE 1024
1486 #define PADSIZE 4096
1487 char buf[MSGSIZE+PADSIZE], *ptr = buf;
1488 #endif
1489 int i;
1490 if (!err)
1491 return ("Successful return: 0");
1492
1493 if (err >= MDB_KEYEXIST && err <= MDB_LAST_ERRCODE) {
1494 i = err - MDB_KEYEXIST;
1495 return mdb_errstr[i];
1496 }
1497
1498 #ifdef _WIN32
1499 /* These are the C-runtime error codes we use. The comment indicates
1500 * their numeric value, and the Win32 error they would correspond to
1501 * if the error actually came from a Win32 API. A major mess, we should
1502 * have used LMDB-specific error codes for everything.
1503 */
1504 switch(err) {
1505 case ENOENT: /* 2, FILE_NOT_FOUND */
1506 case EIO: /* 5, ACCESS_DENIED */
1507 case ENOMEM: /* 12, INVALID_ACCESS */
1508 case EACCES: /* 13, INVALID_DATA */
1509 case EBUSY: /* 16, CURRENT_DIRECTORY */
1510 case EINVAL: /* 22, BAD_COMMAND */
1511 case ENOSPC: /* 28, OUT_OF_PAPER */
1512 return strerror(err);
1513 default:
1514 ;
1515 }
1516 buf[0] = 0;
1517 FormatMessageA(FORMAT_MESSAGE_FROM_SYSTEM |
1518 FORMAT_MESSAGE_IGNORE_INSERTS,
1519 NULL, err, 0, ptr, MSGSIZE, (va_list *)buf+MSGSIZE);
1520 return ptr;
1521 #else
1522 return strerror(err);
1523 #endif
1524 }
1525
1526 /** assert(3) variant in cursor context */
1527 #define mdb_cassert(mc, expr) mdb_assert0((mc)->mc_txn->mt_env, expr, #expr)
1528 /** assert(3) variant in transaction context */
1529 #define mdb_tassert(txn, expr) mdb_assert0((txn)->mt_env, expr, #expr)
1530 /** assert(3) variant in environment context */
1531 #define mdb_eassert(env, expr) mdb_assert0(env, expr, #expr)
1532
1533 #ifndef NDEBUG
1534 # define mdb_assert0(env, expr, expr_txt) ((expr) ? (void)0 : \
1535 mdb_assert_fail(env, expr_txt, mdb_func_, __FILE__, __LINE__))
1536
1537 static void ESECT
mdb_assert_fail(MDB_env * env,const char * expr_txt,const char * func,const char * file,int line)1538 mdb_assert_fail(MDB_env *env, const char *expr_txt,
1539 const char *func, const char *file, int line)
1540 {
1541 char buf[400];
1542 sprintf(buf, "%.100s:%d: Assertion '%.200s' failed in %.40s()",
1543 file, line, expr_txt, func);
1544 if (env->me_assert_func)
1545 env->me_assert_func(env, buf);
1546 fprintf(stderr, "%s\n", buf);
1547 abort();
1548 }
1549 #else
1550 # define mdb_assert0(env, expr, expr_txt) ((void) 0)
1551 #endif /* NDEBUG */
1552
1553 #if MDB_DEBUG
1554 /** Return the page number of \b mp which may be sub-page, for debug output */
1555 static pgno_t
mdb_dbg_pgno(MDB_page * mp)1556 mdb_dbg_pgno(MDB_page *mp)
1557 {
1558 pgno_t ret;
1559 COPY_PGNO(ret, mp->mp_pgno);
1560 return ret;
1561 }
1562
1563 /** Display a key in hexadecimal and return the address of the result.
1564 * @param[in] key the key to display
1565 * @param[in] buf the buffer to write into. Should always be #DKBUF.
1566 * @return The key in hexadecimal form.
1567 */
1568 char *
mdb_dkey(MDB_val * key,char * buf)1569 mdb_dkey(MDB_val *key, char *buf)
1570 {
1571 char *ptr = buf;
1572 unsigned char *c = key->mv_data;
1573 unsigned int i;
1574
1575 if (!key)
1576 return "";
1577
1578 if (key->mv_size > DKBUF_MAXKEYSIZE)
1579 return "MDB_MAXKEYSIZE";
1580 /* may want to make this a dynamic check: if the key is mostly
1581 * printable characters, print it as-is instead of converting to hex.
1582 */
1583 #if 1
1584 buf[0] = '\0';
1585 for (i=0; i<key->mv_size; i++)
1586 ptr += sprintf(ptr, "%02x", *c++);
1587 #else
1588 sprintf(buf, "%.*s", key->mv_size, key->mv_data);
1589 #endif
1590 return buf;
1591 }
1592
1593 static const char *
mdb_leafnode_type(MDB_node * n)1594 mdb_leafnode_type(MDB_node *n)
1595 {
1596 static char *const tp[2][2] = {{"", ": DB"}, {": sub-page", ": sub-DB"}};
1597 return F_ISSET(n->mn_flags, F_BIGDATA) ? ": overflow page" :
1598 tp[F_ISSET(n->mn_flags, F_DUPDATA)][F_ISSET(n->mn_flags, F_SUBDATA)];
1599 }
1600
1601 /** Display all the keys in the page. */
1602 void
mdb_page_list(MDB_page * mp)1603 mdb_page_list(MDB_page *mp)
1604 {
1605 pgno_t pgno = mdb_dbg_pgno(mp);
1606 const char *type, *state = (mp->mp_flags & P_DIRTY) ? ", dirty" : "";
1607 MDB_node *node;
1608 unsigned int i, nkeys, nsize, total = 0;
1609 MDB_val key;
1610 DKBUF;
1611
1612 switch (mp->mp_flags & (P_BRANCH|P_LEAF|P_LEAF2|P_META|P_OVERFLOW|P_SUBP)) {
1613 case P_BRANCH: type = "Branch page"; break;
1614 case P_LEAF: type = "Leaf page"; break;
1615 case P_LEAF|P_SUBP: type = "Sub-page"; break;
1616 case P_LEAF|P_LEAF2: type = "LEAF2 page"; break;
1617 case P_LEAF|P_LEAF2|P_SUBP: type = "LEAF2 sub-page"; break;
1618 case P_OVERFLOW:
1619 fprintf(stderr, "Overflow page %"Z"u pages %u%s\n",
1620 pgno, mp->mp_pages, state);
1621 return;
1622 case P_META:
1623 fprintf(stderr, "Meta-page %"Z"u txnid %"Z"u\n",
1624 pgno, ((MDB_meta *)METADATA(mp))->mm_txnid);
1625 return;
1626 default:
1627 fprintf(stderr, "Bad page %"Z"u flags 0x%X\n", pgno, mp->mp_flags);
1628 return;
1629 }
1630
1631 nkeys = NUMKEYS(mp);
1632 fprintf(stderr, "%s %"Z"u numkeys %d%s\n", type, pgno, nkeys, state);
1633
1634 for (i=0; i<nkeys; i++) {
1635 if (IS_LEAF2(mp)) { /* LEAF2 pages have no mp_ptrs[] or node headers */
1636 key.mv_size = nsize = mp->mp_pad;
1637 key.mv_data = LEAF2KEY(mp, i, nsize);
1638 total += nsize;
1639 fprintf(stderr, "key %d: nsize %d, %s\n", i, nsize, DKEY(&key));
1640 continue;
1641 }
1642 node = NODEPTR(mp, i);
1643 key.mv_size = node->mn_ksize;
1644 key.mv_data = node->mn_data;
1645 nsize = NODESIZE + key.mv_size;
1646 if (IS_BRANCH(mp)) {
1647 fprintf(stderr, "key %d: page %"Z"u, %s\n", i, NODEPGNO(node),
1648 DKEY(&key));
1649 total += nsize;
1650 } else {
1651 if (F_ISSET(node->mn_flags, F_BIGDATA))
1652 nsize += sizeof(pgno_t);
1653 else
1654 nsize += NODEDSZ(node);
1655 total += nsize;
1656 nsize += sizeof(indx_t);
1657 fprintf(stderr, "key %d: nsize %d, %s%s\n",
1658 i, nsize, DKEY(&key), mdb_leafnode_type(node));
1659 }
1660 total = EVEN(total);
1661 }
1662 fprintf(stderr, "Total: header %d + contents %d + unused %d\n",
1663 IS_LEAF2(mp) ? PAGEHDRSZ : PAGEBASE + mp->mp_lower, total, SIZELEFT(mp));
1664 }
1665
1666 void
mdb_cursor_chk(MDB_cursor * mc)1667 mdb_cursor_chk(MDB_cursor *mc)
1668 {
1669 unsigned int i;
1670 MDB_node *node;
1671 MDB_page *mp;
1672
1673 if (!mc->mc_snum || !(mc->mc_flags & C_INITIALIZED)) return;
1674 for (i=0; i<mc->mc_top; i++) {
1675 mp = mc->mc_pg[i];
1676 node = NODEPTR(mp, mc->mc_ki[i]);
1677 if (NODEPGNO(node) != mc->mc_pg[i+1]->mp_pgno)
1678 printf("oops!\n");
1679 }
1680 if (mc->mc_ki[i] >= NUMKEYS(mc->mc_pg[i]))
1681 printf("ack!\n");
1682 if (XCURSOR_INITED(mc)) {
1683 node = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
1684 if (((node->mn_flags & (F_DUPDATA|F_SUBDATA)) == F_DUPDATA) &&
1685 mc->mc_xcursor->mx_cursor.mc_pg[0] != NODEDATA(node)) {
1686 printf("blah!\n");
1687 }
1688 }
1689 }
1690 #endif
1691
1692 #if (MDB_DEBUG) > 2
1693 /** Count all the pages in each DB and in the freelist
1694 * and make sure it matches the actual number of pages
1695 * being used.
1696 * All named DBs must be open for a correct count.
1697 */
mdb_audit(MDB_txn * txn)1698 static void mdb_audit(MDB_txn *txn)
1699 {
1700 MDB_cursor mc;
1701 MDB_val key, data;
1702 MDB_ID freecount, count;
1703 MDB_dbi i;
1704 int rc;
1705
1706 freecount = 0;
1707 mdb_cursor_init(&mc, txn, FREE_DBI, NULL);
1708 while ((rc = mdb_cursor_get(&mc, &key, &data, MDB_NEXT)) == 0)
1709 freecount += *(MDB_ID *)data.mv_data;
1710 mdb_tassert(txn, rc == MDB_NOTFOUND);
1711
1712 count = 0;
1713 for (i = 0; i<txn->mt_numdbs; i++) {
1714 MDB_xcursor mx;
1715 if (!(txn->mt_dbflags[i] & DB_VALID))
1716 continue;
1717 mdb_cursor_init(&mc, txn, i, &mx);
1718 if (txn->mt_dbs[i].md_root == P_INVALID)
1719 continue;
1720 count += txn->mt_dbs[i].md_branch_pages +
1721 txn->mt_dbs[i].md_leaf_pages +
1722 txn->mt_dbs[i].md_overflow_pages;
1723 if (txn->mt_dbs[i].md_flags & MDB_DUPSORT) {
1724 rc = mdb_page_search(&mc, NULL, MDB_PS_FIRST);
1725 for (; rc == MDB_SUCCESS; rc = mdb_cursor_sibling(&mc, 1)) {
1726 unsigned j;
1727 MDB_page *mp;
1728 mp = mc.mc_pg[mc.mc_top];
1729 for (j=0; j<NUMKEYS(mp); j++) {
1730 MDB_node *leaf = NODEPTR(mp, j);
1731 if (leaf->mn_flags & F_SUBDATA) {
1732 MDB_db db;
1733 memcpy(&db, NODEDATA(leaf), sizeof(db));
1734 count += db.md_branch_pages + db.md_leaf_pages +
1735 db.md_overflow_pages;
1736 }
1737 }
1738 }
1739 mdb_tassert(txn, rc == MDB_NOTFOUND);
1740 }
1741 }
1742 if (freecount + count + NUM_METAS != txn->mt_next_pgno) {
1743 fprintf(stderr, "audit: %"Z"u freecount: %"Z"u count: %"Z"u total: %"Z"u next_pgno: %"Z"u\n",
1744 txn->mt_txnid, freecount, count+NUM_METAS,
1745 freecount+count+NUM_METAS, txn->mt_next_pgno);
1746 }
1747 }
1748 #endif
1749
1750 int
mdb_cmp(MDB_txn * txn,MDB_dbi dbi,const MDB_val * a,const MDB_val * b)1751 mdb_cmp(MDB_txn *txn, MDB_dbi dbi, const MDB_val *a, const MDB_val *b)
1752 {
1753 return txn->mt_dbxs[dbi].md_cmp(a, b);
1754 }
1755
1756 int
mdb_dcmp(MDB_txn * txn,MDB_dbi dbi,const MDB_val * a,const MDB_val * b)1757 mdb_dcmp(MDB_txn *txn, MDB_dbi dbi, const MDB_val *a, const MDB_val *b)
1758 {
1759 MDB_cmp_func *dcmp = txn->mt_dbxs[dbi].md_dcmp;
1760 #if UINT_MAX < SIZE_MAX
1761 if (dcmp == mdb_cmp_int && a->mv_size == sizeof(size_t))
1762 dcmp = mdb_cmp_clong;
1763 #endif
1764 return dcmp(a, b);
1765 }
1766
1767 /** Allocate memory for a page.
1768 * Re-use old malloc'd pages first for singletons, otherwise just malloc.
1769 * Set #MDB_TXN_ERROR on failure.
1770 */
1771 static MDB_page *
mdb_page_malloc(MDB_txn * txn,unsigned num)1772 mdb_page_malloc(MDB_txn *txn, unsigned num)
1773 {
1774 MDB_env *env = txn->mt_env;
1775 MDB_page *ret = env->me_dpages;
1776 size_t psize = env->me_psize, sz = psize, off;
1777 /* For ! #MDB_NOMEMINIT, psize counts how much to init.
1778 * For a single page alloc, we init everything after the page header.
1779 * For multi-page, we init the final page; if the caller needed that
1780 * many pages they will be filling in at least up to the last page.
1781 */
1782 if (num == 1) {
1783 if (ret) {
1784 VGMEMP_ALLOC(env, ret, sz);
1785 VGMEMP_DEFINED(ret, sizeof(ret->mp_next));
1786 env->me_dpages = ret->mp_next;
1787 return ret;
1788 }
1789 psize -= off = PAGEHDRSZ;
1790 } else {
1791 sz *= num;
1792 off = sz - psize;
1793 }
1794 if ((ret = malloc(sz)) != NULL) {
1795 VGMEMP_ALLOC(env, ret, sz);
1796 if (!(env->me_flags & MDB_NOMEMINIT)) {
1797 memset((char *)ret + off, 0, psize);
1798 ret->mp_pad = 0;
1799 }
1800 } else {
1801 txn->mt_flags |= MDB_TXN_ERROR;
1802 }
1803 return ret;
1804 }
1805 /** Free a single page.
1806 * Saves single pages to a list, for future reuse.
1807 * (This is not used for multi-page overflow pages.)
1808 */
1809 static void
mdb_page_free(MDB_env * env,MDB_page * mp)1810 mdb_page_free(MDB_env *env, MDB_page *mp)
1811 {
1812 mp->mp_next = env->me_dpages;
1813 VGMEMP_FREE(env, mp);
1814 env->me_dpages = mp;
1815 }
1816
1817 /** Free a dirty page */
1818 static void
mdb_dpage_free(MDB_env * env,MDB_page * dp)1819 mdb_dpage_free(MDB_env *env, MDB_page *dp)
1820 {
1821 if (!IS_OVERFLOW(dp) || dp->mp_pages == 1) {
1822 mdb_page_free(env, dp);
1823 } else {
1824 /* large pages just get freed directly */
1825 VGMEMP_FREE(env, dp);
1826 free(dp);
1827 }
1828 }
1829
1830 /** Return all dirty pages to dpage list */
1831 static void
mdb_dlist_free(MDB_txn * txn)1832 mdb_dlist_free(MDB_txn *txn)
1833 {
1834 MDB_env *env = txn->mt_env;
1835 MDB_ID2L dl = txn->mt_u.dirty_list;
1836 unsigned i, n = dl[0].mid;
1837
1838 for (i = 1; i <= n; i++) {
1839 mdb_dpage_free(env, dl[i].mptr);
1840 }
1841 dl[0].mid = 0;
1842 }
1843
1844 /** Loosen or free a single page.
1845 * Saves single pages to a list for future reuse
1846 * in this same txn. It has been pulled from the freeDB
1847 * and already resides on the dirty list, but has been
1848 * deleted. Use these pages first before pulling again
1849 * from the freeDB.
1850 *
1851 * If the page wasn't dirtied in this txn, just add it
1852 * to this txn's free list.
1853 */
1854 static int
mdb_page_loose(MDB_cursor * mc,MDB_page * mp)1855 mdb_page_loose(MDB_cursor *mc, MDB_page *mp)
1856 {
1857 int loose = 0;
1858 pgno_t pgno = mp->mp_pgno;
1859 MDB_txn *txn = mc->mc_txn;
1860
1861 if ((mp->mp_flags & P_DIRTY) && mc->mc_dbi != FREE_DBI) {
1862 if (txn->mt_parent) {
1863 MDB_ID2 *dl = txn->mt_u.dirty_list;
1864 /* If txn has a parent, make sure the page is in our
1865 * dirty list.
1866 */
1867 if (dl[0].mid) {
1868 unsigned x = mdb_mid2l_search(dl, pgno);
1869 if (x <= dl[0].mid && dl[x].mid == pgno) {
1870 if (mp != dl[x].mptr) { /* bad cursor? */
1871 mc->mc_flags &= ~(C_INITIALIZED|C_EOF);
1872 txn->mt_flags |= MDB_TXN_ERROR;
1873 return MDB_CORRUPTED;
1874 }
1875 /* ok, it's ours */
1876 loose = 1;
1877 }
1878 }
1879 } else {
1880 /* no parent txn, so it's just ours */
1881 loose = 1;
1882 }
1883 }
1884 if (loose) {
1885 DPRINTF(("loosen db %d page %"Z"u", DDBI(mc),
1886 mp->mp_pgno));
1887 NEXT_LOOSE_PAGE(mp) = txn->mt_loose_pgs;
1888 txn->mt_loose_pgs = mp;
1889 txn->mt_loose_count++;
1890 mp->mp_flags |= P_LOOSE;
1891 } else {
1892 int rc = mdb_midl_append(&txn->mt_free_pgs, pgno);
1893 if (rc)
1894 return rc;
1895 }
1896
1897 return MDB_SUCCESS;
1898 }
1899
1900 /** Set or clear P_KEEP in dirty, non-overflow, non-sub pages watched by txn.
1901 * @param[in] mc A cursor handle for the current operation.
1902 * @param[in] pflags Flags of the pages to update:
1903 * P_DIRTY to set P_KEEP, P_DIRTY|P_KEEP to clear it.
1904 * @param[in] all No shortcuts. Needed except after a full #mdb_page_flush().
1905 * @return 0 on success, non-zero on failure.
1906 */
1907 static int
mdb_pages_xkeep(MDB_cursor * mc,unsigned pflags,int all)1908 mdb_pages_xkeep(MDB_cursor *mc, unsigned pflags, int all)
1909 {
1910 enum { Mask = P_SUBP|P_DIRTY|P_LOOSE|P_KEEP };
1911 MDB_txn *txn = mc->mc_txn;
1912 MDB_cursor *m3, *m0 = mc;
1913 MDB_xcursor *mx;
1914 MDB_page *dp, *mp;
1915 MDB_node *leaf;
1916 unsigned i, j;
1917 int rc = MDB_SUCCESS, level;
1918
1919 /* Mark pages seen by cursors */
1920 if (mc->mc_flags & C_UNTRACK)
1921 mc = NULL; /* will find mc in mt_cursors */
1922 for (i = txn->mt_numdbs;; mc = txn->mt_cursors[--i]) {
1923 for (; mc; mc=mc->mc_next) {
1924 if (!(mc->mc_flags & C_INITIALIZED))
1925 continue;
1926 for (m3 = mc;; m3 = &mx->mx_cursor) {
1927 mp = NULL;
1928 for (j=0; j<m3->mc_snum; j++) {
1929 mp = m3->mc_pg[j];
1930 if ((mp->mp_flags & Mask) == pflags)
1931 mp->mp_flags ^= P_KEEP;
1932 }
1933 mx = m3->mc_xcursor;
1934 /* Proceed to mx if it is at a sub-database */
1935 if (! (mx && (mx->mx_cursor.mc_flags & C_INITIALIZED)))
1936 break;
1937 if (! (mp && (mp->mp_flags & P_LEAF)))
1938 break;
1939 leaf = NODEPTR(mp, m3->mc_ki[j-1]);
1940 if (!(leaf->mn_flags & F_SUBDATA))
1941 break;
1942 }
1943 }
1944 if (i == 0)
1945 break;
1946 }
1947
1948 if (all) {
1949 /* Mark dirty root pages */
1950 for (i=0; i<txn->mt_numdbs; i++) {
1951 if (txn->mt_dbflags[i] & DB_DIRTY) {
1952 pgno_t pgno = txn->mt_dbs[i].md_root;
1953 if (pgno == P_INVALID)
1954 continue;
1955 if ((rc = mdb_page_get(m0, pgno, &dp, &level)) != MDB_SUCCESS)
1956 break;
1957 if ((dp->mp_flags & Mask) == pflags && level <= 1)
1958 dp->mp_flags ^= P_KEEP;
1959 }
1960 }
1961 }
1962
1963 return rc;
1964 }
1965
1966 static int mdb_page_flush(MDB_txn *txn, int keep);
1967
1968 /** Spill pages from the dirty list back to disk.
1969 * This is intended to prevent running into #MDB_TXN_FULL situations,
1970 * but note that they may still occur in a few cases:
1971 * 1) our estimate of the txn size could be too small. Currently this
1972 * seems unlikely, except with a large number of #MDB_MULTIPLE items.
1973 * 2) child txns may run out of space if their parents dirtied a
1974 * lot of pages and never spilled them. TODO: we probably should do
1975 * a preemptive spill during #mdb_txn_begin() of a child txn, if
1976 * the parent's dirty_room is below a given threshold.
1977 *
1978 * Otherwise, if not using nested txns, it is expected that apps will
1979 * not run into #MDB_TXN_FULL any more. The pages are flushed to disk
1980 * the same way as for a txn commit, e.g. their P_DIRTY flag is cleared.
1981 * If the txn never references them again, they can be left alone.
1982 * If the txn only reads them, they can be used without any fuss.
1983 * If the txn writes them again, they can be dirtied immediately without
1984 * going thru all of the work of #mdb_page_touch(). Such references are
1985 * handled by #mdb_page_unspill().
1986 *
1987 * Also note, we never spill DB root pages, nor pages of active cursors,
1988 * because we'll need these back again soon anyway. And in nested txns,
1989 * we can't spill a page in a child txn if it was already spilled in a
1990 * parent txn. That would alter the parent txns' data even though
1991 * the child hasn't committed yet, and we'd have no way to undo it if
1992 * the child aborted.
1993 *
1994 * @param[in] m0 cursor A cursor handle identifying the transaction and
1995 * database for which we are checking space.
1996 * @param[in] key For a put operation, the key being stored.
1997 * @param[in] data For a put operation, the data being stored.
1998 * @return 0 on success, non-zero on failure.
1999 */
2000 static int
mdb_page_spill(MDB_cursor * m0,MDB_val * key,MDB_val * data)2001 mdb_page_spill(MDB_cursor *m0, MDB_val *key, MDB_val *data)
2002 {
2003 MDB_txn *txn = m0->mc_txn;
2004 MDB_page *dp;
2005 MDB_ID2L dl = txn->mt_u.dirty_list;
2006 unsigned int i, j, need;
2007 int rc;
2008
2009 if (m0->mc_flags & C_SUB)
2010 return MDB_SUCCESS;
2011
2012 /* Estimate how much space this op will take */
2013 i = m0->mc_db->md_depth;
2014 /* Named DBs also dirty the main DB */
2015 if (m0->mc_dbi >= CORE_DBS)
2016 i += txn->mt_dbs[MAIN_DBI].md_depth;
2017 /* For puts, roughly factor in the key+data size */
2018 if (key)
2019 i += (LEAFSIZE(key, data) + txn->mt_env->me_psize) / txn->mt_env->me_psize;
2020 i += i; /* double it for good measure */
2021 need = i;
2022
2023 if (txn->mt_dirty_room > i)
2024 return MDB_SUCCESS;
2025
2026 if (!txn->mt_spill_pgs) {
2027 txn->mt_spill_pgs = mdb_midl_alloc(MDB_IDL_UM_MAX);
2028 if (!txn->mt_spill_pgs)
2029 return ENOMEM;
2030 } else {
2031 /* purge deleted slots */
2032 MDB_IDL sl = txn->mt_spill_pgs;
2033 unsigned int num = sl[0];
2034 j=0;
2035 for (i=1; i<=num; i++) {
2036 if (!(sl[i] & 1))
2037 sl[++j] = sl[i];
2038 }
2039 sl[0] = j;
2040 }
2041
2042 /* Preserve pages which may soon be dirtied again */
2043 if ((rc = mdb_pages_xkeep(m0, P_DIRTY, 1)) != MDB_SUCCESS)
2044 goto done;
2045
2046 /* Less aggressive spill - we originally spilled the entire dirty list,
2047 * with a few exceptions for cursor pages and DB root pages. But this
2048 * turns out to be a lot of wasted effort because in a large txn many
2049 * of those pages will need to be used again. So now we spill only 1/8th
2050 * of the dirty pages. Testing revealed this to be a good tradeoff,
2051 * better than 1/2, 1/4, or 1/10.
2052 */
2053 if (need < MDB_IDL_UM_MAX / 8)
2054 need = MDB_IDL_UM_MAX / 8;
2055
2056 /* Save the page IDs of all the pages we're flushing */
2057 /* flush from the tail forward, this saves a lot of shifting later on. */
2058 for (i=dl[0].mid; i && need; i--) {
2059 MDB_ID pn = dl[i].mid << 1;
2060 dp = dl[i].mptr;
2061 if (dp->mp_flags & (P_LOOSE|P_KEEP))
2062 continue;
2063 /* Can't spill twice, make sure it's not already in a parent's
2064 * spill list.
2065 */
2066 if (txn->mt_parent) {
2067 MDB_txn *tx2;
2068 for (tx2 = txn->mt_parent; tx2; tx2 = tx2->mt_parent) {
2069 if (tx2->mt_spill_pgs) {
2070 j = mdb_midl_search(tx2->mt_spill_pgs, pn);
2071 if (j <= tx2->mt_spill_pgs[0] && tx2->mt_spill_pgs[j] == pn) {
2072 dp->mp_flags |= P_KEEP;
2073 break;
2074 }
2075 }
2076 }
2077 if (tx2)
2078 continue;
2079 }
2080 if ((rc = mdb_midl_append(&txn->mt_spill_pgs, pn)))
2081 goto done;
2082 need--;
2083 }
2084 mdb_midl_sort(txn->mt_spill_pgs);
2085
2086 /* Flush the spilled part of dirty list */
2087 if ((rc = mdb_page_flush(txn, i)) != MDB_SUCCESS)
2088 goto done;
2089
2090 /* Reset any dirty pages we kept that page_flush didn't see */
2091 rc = mdb_pages_xkeep(m0, P_DIRTY|P_KEEP, i);
2092
2093 done:
2094 txn->mt_flags |= rc ? MDB_TXN_ERROR : MDB_TXN_SPILLS;
2095 return rc;
2096 }
2097
2098 /** Find oldest txnid still referenced. Expects txn->mt_txnid > 0. */
2099 static txnid_t
mdb_find_oldest(MDB_txn * txn)2100 mdb_find_oldest(MDB_txn *txn)
2101 {
2102 int i;
2103 txnid_t mr, oldest = txn->mt_txnid - 1;
2104 if (txn->mt_env->me_txns) {
2105 MDB_reader *r = txn->mt_env->me_txns->mti_readers;
2106 for (i = txn->mt_env->me_txns->mti_numreaders; --i >= 0; ) {
2107 if (r[i].mr_pid) {
2108 mr = r[i].mr_txnid;
2109 if (oldest > mr)
2110 oldest = mr;
2111 }
2112 }
2113 }
2114 return oldest;
2115 }
2116
2117 /** Add a page to the txn's dirty list */
2118 static void
mdb_page_dirty(MDB_txn * txn,MDB_page * mp)2119 mdb_page_dirty(MDB_txn *txn, MDB_page *mp)
2120 {
2121 MDB_ID2 mid;
2122 int rc, (*insert)(MDB_ID2L, MDB_ID2 *);
2123
2124 if (txn->mt_flags & MDB_TXN_WRITEMAP) {
2125 insert = mdb_mid2l_append;
2126 } else {
2127 insert = mdb_mid2l_insert;
2128 }
2129 mid.mid = mp->mp_pgno;
2130 mid.mptr = mp;
2131 rc = insert(txn->mt_u.dirty_list, &mid);
2132 mdb_tassert(txn, rc == 0);
2133 txn->mt_dirty_room--;
2134 }
2135
2136 /** Allocate page numbers and memory for writing. Maintain me_pglast,
2137 * me_pghead and mt_next_pgno. Set #MDB_TXN_ERROR on failure.
2138 *
2139 * If there are free pages available from older transactions, they
2140 * are re-used first. Otherwise allocate a new page at mt_next_pgno.
2141 * Do not modify the freedB, just merge freeDB records into me_pghead[]
2142 * and move me_pglast to say which records were consumed. Only this
2143 * function can create me_pghead and move me_pglast/mt_next_pgno.
2144 * @param[in] mc cursor A cursor handle identifying the transaction and
2145 * database for which we are allocating.
2146 * @param[in] num the number of pages to allocate.
2147 * @param[out] mp Address of the allocated page(s). Requests for multiple pages
2148 * will always be satisfied by a single contiguous chunk of memory.
2149 * @return 0 on success, non-zero on failure.
2150 */
2151 static int
mdb_page_alloc(MDB_cursor * mc,int num,MDB_page ** mp)2152 mdb_page_alloc(MDB_cursor *mc, int num, MDB_page **mp)
2153 {
2154 #ifdef MDB_PARANOID /* Seems like we can ignore this now */
2155 /* Get at most <Max_retries> more freeDB records once me_pghead
2156 * has enough pages. If not enough, use new pages from the map.
2157 * If <Paranoid> and mc is updating the freeDB, only get new
2158 * records if me_pghead is empty. Then the freelist cannot play
2159 * catch-up with itself by growing while trying to save it.
2160 */
2161 enum { Paranoid = 1, Max_retries = 500 };
2162 #else
2163 enum { Paranoid = 0, Max_retries = INT_MAX /*infinite*/ };
2164 #endif
2165 int rc, retry = num * 60;
2166 MDB_txn *txn = mc->mc_txn;
2167 MDB_env *env = txn->mt_env;
2168 pgno_t pgno, *mop = env->me_pghead;
2169 unsigned i, j, mop_len = mop ? mop[0] : 0, n2 = num-1;
2170 MDB_page *np;
2171 txnid_t oldest = 0, last;
2172 MDB_cursor_op op;
2173 MDB_cursor m2;
2174 int found_old = 0;
2175
2176 /* If there are any loose pages, just use them */
2177 if (num == 1 && txn->mt_loose_pgs) {
2178 np = txn->mt_loose_pgs;
2179 txn->mt_loose_pgs = NEXT_LOOSE_PAGE(np);
2180 txn->mt_loose_count--;
2181 DPRINTF(("db %d use loose page %"Z"u", DDBI(mc),
2182 np->mp_pgno));
2183 *mp = np;
2184 return MDB_SUCCESS;
2185 }
2186
2187 *mp = NULL;
2188
2189 /* If our dirty list is already full, we can't do anything */
2190 if (txn->mt_dirty_room == 0) {
2191 rc = MDB_TXN_FULL;
2192 goto fail;
2193 }
2194
2195 for (op = MDB_FIRST;; op = MDB_NEXT) {
2196 MDB_val key, data;
2197 MDB_node *leaf;
2198 pgno_t *idl;
2199
2200 /* Seek a big enough contiguous page range. Prefer
2201 * pages at the tail, just truncating the list.
2202 */
2203 if (mop_len > n2) {
2204 i = mop_len;
2205 do {
2206 pgno = mop[i];
2207 if (mop[i-n2] == pgno+n2)
2208 goto search_done;
2209 } while (--i > n2);
2210 if (--retry < 0)
2211 break;
2212 }
2213
2214 if (op == MDB_FIRST) { /* 1st iteration */
2215 /* Prepare to fetch more and coalesce */
2216 last = env->me_pglast;
2217 oldest = env->me_pgoldest;
2218 mdb_cursor_init(&m2, txn, FREE_DBI, NULL);
2219 if (last) {
2220 op = MDB_SET_RANGE;
2221 key.mv_data = &last; /* will look up last+1 */
2222 key.mv_size = sizeof(last);
2223 }
2224 if (Paranoid && mc->mc_dbi == FREE_DBI)
2225 retry = -1;
2226 }
2227 if (Paranoid && retry < 0 && mop_len)
2228 break;
2229
2230 last++;
2231 /* Do not fetch more if the record will be too recent */
2232 if (oldest <= last) {
2233 if (!found_old) {
2234 oldest = mdb_find_oldest(txn);
2235 env->me_pgoldest = oldest;
2236 found_old = 1;
2237 }
2238 if (oldest <= last)
2239 break;
2240 }
2241 rc = mdb_cursor_get(&m2, &key, NULL, op);
2242 if (rc) {
2243 if (rc == MDB_NOTFOUND)
2244 break;
2245 goto fail;
2246 }
2247 last = *(txnid_t*)key.mv_data;
2248 if (oldest <= last) {
2249 if (!found_old) {
2250 oldest = mdb_find_oldest(txn);
2251 env->me_pgoldest = oldest;
2252 found_old = 1;
2253 }
2254 if (oldest <= last)
2255 break;
2256 }
2257 np = m2.mc_pg[m2.mc_top];
2258 leaf = NODEPTR(np, m2.mc_ki[m2.mc_top]);
2259 if ((rc = mdb_node_read(&m2, leaf, &data)) != MDB_SUCCESS)
2260 goto fail;
2261
2262 idl = (MDB_ID *) data.mv_data;
2263 i = idl[0];
2264 if (!mop) {
2265 if (!(env->me_pghead = mop = mdb_midl_alloc(i))) {
2266 rc = ENOMEM;
2267 goto fail;
2268 }
2269 } else {
2270 if ((rc = mdb_midl_need(&env->me_pghead, i)) != 0)
2271 goto fail;
2272 mop = env->me_pghead;
2273 }
2274 env->me_pglast = last;
2275 #if (MDB_DEBUG) > 1
2276 DPRINTF(("IDL read txn %"Z"u root %"Z"u num %u",
2277 last, txn->mt_dbs[FREE_DBI].md_root, i));
2278 for (j = i; j; j--)
2279 DPRINTF(("IDL %"Z"u", idl[j]));
2280 #endif
2281 /* Merge in descending sorted order */
2282 mdb_midl_xmerge(mop, idl);
2283 mop_len = mop[0];
2284 }
2285
2286 /* Use new pages from the map when nothing suitable in the freeDB */
2287 i = 0;
2288 pgno = txn->mt_next_pgno;
2289 if (pgno + num >= env->me_maxpg) {
2290 DPUTS("DB size maxed out");
2291 rc = MDB_MAP_FULL;
2292 goto fail;
2293 }
2294
2295 search_done:
2296 if (env->me_flags & MDB_WRITEMAP) {
2297 np = (MDB_page *)(env->me_map + env->me_psize * pgno);
2298 } else {
2299 if (!(np = mdb_page_malloc(txn, num))) {
2300 rc = ENOMEM;
2301 goto fail;
2302 }
2303 }
2304 if (i) {
2305 mop[0] = mop_len -= num;
2306 /* Move any stragglers down */
2307 for (j = i-num; j < mop_len; )
2308 mop[++j] = mop[++i];
2309 } else {
2310 txn->mt_next_pgno = pgno + num;
2311 }
2312 np->mp_pgno = pgno;
2313 mdb_page_dirty(txn, np);
2314 *mp = np;
2315
2316 return MDB_SUCCESS;
2317
2318 fail:
2319 txn->mt_flags |= MDB_TXN_ERROR;
2320 return rc;
2321 }
2322
2323 /** Copy the used portions of a non-overflow page.
2324 * @param[in] dst page to copy into
2325 * @param[in] src page to copy from
2326 * @param[in] psize size of a page
2327 */
2328 static void
mdb_page_copy(MDB_page * dst,MDB_page * src,unsigned int psize)2329 mdb_page_copy(MDB_page *dst, MDB_page *src, unsigned int psize)
2330 {
2331 enum { Align = sizeof(pgno_t) };
2332 indx_t upper = src->mp_upper, lower = src->mp_lower, unused = upper-lower;
2333
2334 /* If page isn't full, just copy the used portion. Adjust
2335 * alignment so memcpy may copy words instead of bytes.
2336 */
2337 if ((unused &= -Align) && !IS_LEAF2(src)) {
2338 upper = (upper + PAGEBASE) & -Align;
2339 memcpy(dst, src, (lower + PAGEBASE + (Align-1)) & -Align);
2340 memcpy((pgno_t *)((char *)dst+upper), (pgno_t *)((char *)src+upper),
2341 psize - upper);
2342 } else {
2343 memcpy(dst, src, psize - unused);
2344 }
2345 }
2346
2347 /** Pull a page off the txn's spill list, if present.
2348 * If a page being referenced was spilled to disk in this txn, bring
2349 * it back and make it dirty/writable again.
2350 * @param[in] txn the transaction handle.
2351 * @param[in] mp the page being referenced. It must not be dirty.
2352 * @param[out] ret the writable page, if any. ret is unchanged if
2353 * mp wasn't spilled.
2354 */
2355 static int
mdb_page_unspill(MDB_txn * txn,MDB_page * mp,MDB_page ** ret)2356 mdb_page_unspill(MDB_txn *txn, MDB_page *mp, MDB_page **ret)
2357 {
2358 MDB_env *env = txn->mt_env;
2359 const MDB_txn *tx2;
2360 unsigned x;
2361 pgno_t pgno = mp->mp_pgno, pn = pgno << 1;
2362
2363 for (tx2 = txn; tx2; tx2=tx2->mt_parent) {
2364 if (!tx2->mt_spill_pgs)
2365 continue;
2366 x = mdb_midl_search(tx2->mt_spill_pgs, pn);
2367 if (x <= tx2->mt_spill_pgs[0] && tx2->mt_spill_pgs[x] == pn) {
2368 MDB_page *np;
2369 int num;
2370 if (txn->mt_dirty_room == 0)
2371 return MDB_TXN_FULL;
2372 if (IS_OVERFLOW(mp))
2373 num = mp->mp_pages;
2374 else
2375 num = 1;
2376 if (env->me_flags & MDB_WRITEMAP) {
2377 np = mp;
2378 } else {
2379 np = mdb_page_malloc(txn, num);
2380 if (!np)
2381 return ENOMEM;
2382 if (num > 1)
2383 memcpy(np, mp, num * env->me_psize);
2384 else
2385 mdb_page_copy(np, mp, env->me_psize);
2386 }
2387 if (tx2 == txn) {
2388 /* If in current txn, this page is no longer spilled.
2389 * If it happens to be the last page, truncate the spill list.
2390 * Otherwise mark it as deleted by setting the LSB.
2391 */
2392 if (x == txn->mt_spill_pgs[0])
2393 txn->mt_spill_pgs[0]--;
2394 else
2395 txn->mt_spill_pgs[x] |= 1;
2396 } /* otherwise, if belonging to a parent txn, the
2397 * page remains spilled until child commits
2398 */
2399
2400 mdb_page_dirty(txn, np);
2401 np->mp_flags |= P_DIRTY;
2402 *ret = np;
2403 break;
2404 }
2405 }
2406 return MDB_SUCCESS;
2407 }
2408
2409 /** Touch a page: make it dirty and re-insert into tree with updated pgno.
2410 * Set #MDB_TXN_ERROR on failure.
2411 * @param[in] mc cursor pointing to the page to be touched
2412 * @return 0 on success, non-zero on failure.
2413 */
2414 static int
mdb_page_touch(MDB_cursor * mc)2415 mdb_page_touch(MDB_cursor *mc)
2416 {
2417 MDB_page *mp = mc->mc_pg[mc->mc_top], *np;
2418 MDB_txn *txn = mc->mc_txn;
2419 MDB_cursor *m2, *m3;
2420 pgno_t pgno;
2421 int rc;
2422
2423 if (!F_ISSET(mp->mp_flags, P_DIRTY)) {
2424 if (txn->mt_flags & MDB_TXN_SPILLS) {
2425 np = NULL;
2426 rc = mdb_page_unspill(txn, mp, &np);
2427 if (rc)
2428 goto fail;
2429 if (np)
2430 goto done;
2431 }
2432 if ((rc = mdb_midl_need(&txn->mt_free_pgs, 1)) ||
2433 (rc = mdb_page_alloc(mc, 1, &np)))
2434 goto fail;
2435 pgno = np->mp_pgno;
2436 DPRINTF(("touched db %d page %"Z"u -> %"Z"u", DDBI(mc),
2437 mp->mp_pgno, pgno));
2438 mdb_cassert(mc, mp->mp_pgno != pgno);
2439 mdb_midl_xappend(txn->mt_free_pgs, mp->mp_pgno);
2440 /* Update the parent page, if any, to point to the new page */
2441 if (mc->mc_top) {
2442 MDB_page *parent = mc->mc_pg[mc->mc_top-1];
2443 MDB_node *node = NODEPTR(parent, mc->mc_ki[mc->mc_top-1]);
2444 SETPGNO(node, pgno);
2445 } else {
2446 mc->mc_db->md_root = pgno;
2447 }
2448 } else if (txn->mt_parent && !IS_SUBP(mp)) {
2449 MDB_ID2 mid, *dl = txn->mt_u.dirty_list;
2450 pgno = mp->mp_pgno;
2451 /* If txn has a parent, make sure the page is in our
2452 * dirty list.
2453 */
2454 if (dl[0].mid) {
2455 unsigned x = mdb_mid2l_search(dl, pgno);
2456 if (x <= dl[0].mid && dl[x].mid == pgno) {
2457 if (mp != dl[x].mptr) { /* bad cursor? */
2458 mc->mc_flags &= ~(C_INITIALIZED|C_EOF);
2459 txn->mt_flags |= MDB_TXN_ERROR;
2460 return MDB_CORRUPTED;
2461 }
2462 return 0;
2463 }
2464 }
2465 mdb_cassert(mc, dl[0].mid < MDB_IDL_UM_MAX);
2466 /* No - copy it */
2467 np = mdb_page_malloc(txn, 1);
2468 if (!np)
2469 return ENOMEM;
2470 mid.mid = pgno;
2471 mid.mptr = np;
2472 rc = mdb_mid2l_insert(dl, &mid);
2473 mdb_cassert(mc, rc == 0);
2474 } else {
2475 return 0;
2476 }
2477
2478 mdb_page_copy(np, mp, txn->mt_env->me_psize);
2479 np->mp_pgno = pgno;
2480 np->mp_flags |= P_DIRTY;
2481
2482 done:
2483 /* Adjust cursors pointing to mp */
2484 mc->mc_pg[mc->mc_top] = np;
2485 m2 = txn->mt_cursors[mc->mc_dbi];
2486 if (mc->mc_flags & C_SUB) {
2487 for (; m2; m2=m2->mc_next) {
2488 m3 = &m2->mc_xcursor->mx_cursor;
2489 if (m3->mc_snum < mc->mc_snum) continue;
2490 if (m3->mc_pg[mc->mc_top] == mp)
2491 m3->mc_pg[mc->mc_top] = np;
2492 }
2493 } else {
2494 for (; m2; m2=m2->mc_next) {
2495 if (m2->mc_snum < mc->mc_snum) continue;
2496 if (m2 == mc) continue;
2497 if (m2->mc_pg[mc->mc_top] == mp) {
2498 m2->mc_pg[mc->mc_top] = np;
2499 if (IS_LEAF(np))
2500 XCURSOR_REFRESH(m2, mc->mc_top, np);
2501 }
2502 }
2503 }
2504 return 0;
2505
2506 fail:
2507 txn->mt_flags |= MDB_TXN_ERROR;
2508 return rc;
2509 }
2510
2511 int
mdb_env_sync(MDB_env * env,int force)2512 mdb_env_sync(MDB_env *env, int force)
2513 {
2514 int rc = 0;
2515 if (env->me_flags & MDB_RDONLY)
2516 return EACCES;
2517 if (force || !F_ISSET(env->me_flags, MDB_NOSYNC)) {
2518 if (env->me_flags & MDB_WRITEMAP) {
2519 int flags = ((env->me_flags & MDB_MAPASYNC) && !force)
2520 ? MS_ASYNC : MS_SYNC;
2521 if (MDB_MSYNC(env->me_map, env->me_mapsize, flags))
2522 rc = ErrCode();
2523 #ifdef _WIN32
2524 else if (flags == MS_SYNC && MDB_FDATASYNC(env->me_fd))
2525 rc = ErrCode();
2526 #endif
2527 } else {
2528 #ifdef BROKEN_FDATASYNC
2529 if (env->me_flags & MDB_FSYNCONLY) {
2530 if (fsync(env->me_fd))
2531 rc = ErrCode();
2532 } else
2533 #endif
2534 if (MDB_FDATASYNC(env->me_fd))
2535 rc = ErrCode();
2536 }
2537 }
2538 return rc;
2539 }
2540
2541 /** Back up parent txn's cursors, then grab the originals for tracking */
2542 static int
mdb_cursor_shadow(MDB_txn * src,MDB_txn * dst)2543 mdb_cursor_shadow(MDB_txn *src, MDB_txn *dst)
2544 {
2545 MDB_cursor *mc, *bk;
2546 MDB_xcursor *mx;
2547 size_t size;
2548 int i;
2549
2550 for (i = src->mt_numdbs; --i >= 0; ) {
2551 if ((mc = src->mt_cursors[i]) != NULL) {
2552 size = sizeof(MDB_cursor);
2553 if (mc->mc_xcursor)
2554 size += sizeof(MDB_xcursor);
2555 for (; mc; mc = bk->mc_next) {
2556 bk = malloc(size);
2557 if (!bk)
2558 return ENOMEM;
2559 *bk = *mc;
2560 mc->mc_backup = bk;
2561 mc->mc_db = &dst->mt_dbs[i];
2562 /* Kill pointers into src to reduce abuse: The
2563 * user may not use mc until dst ends. But we need a valid
2564 * txn pointer here for cursor fixups to keep working.
2565 */
2566 mc->mc_txn = dst;
2567 mc->mc_dbflag = &dst->mt_dbflags[i];
2568 if ((mx = mc->mc_xcursor) != NULL) {
2569 *(MDB_xcursor *)(bk+1) = *mx;
2570 mx->mx_cursor.mc_txn = dst;
2571 }
2572 mc->mc_next = dst->mt_cursors[i];
2573 dst->mt_cursors[i] = mc;
2574 }
2575 }
2576 }
2577 return MDB_SUCCESS;
2578 }
2579
2580 /** Close this write txn's cursors, give parent txn's cursors back to parent.
2581 * @param[in] txn the transaction handle.
2582 * @param[in] merge true to keep changes to parent cursors, false to revert.
2583 * @return 0 on success, non-zero on failure.
2584 */
2585 static void
mdb_cursors_close(MDB_txn * txn,unsigned merge)2586 mdb_cursors_close(MDB_txn *txn, unsigned merge)
2587 {
2588 MDB_cursor **cursors = txn->mt_cursors, *mc, *next, *bk;
2589 MDB_xcursor *mx;
2590 int i;
2591
2592 for (i = txn->mt_numdbs; --i >= 0; ) {
2593 for (mc = cursors[i]; mc; mc = next) {
2594 next = mc->mc_next;
2595 if ((bk = mc->mc_backup) != NULL) {
2596 if (merge) {
2597 /* Commit changes to parent txn */
2598 mc->mc_next = bk->mc_next;
2599 mc->mc_backup = bk->mc_backup;
2600 mc->mc_txn = bk->mc_txn;
2601 mc->mc_db = bk->mc_db;
2602 mc->mc_dbflag = bk->mc_dbflag;
2603 if ((mx = mc->mc_xcursor) != NULL)
2604 mx->mx_cursor.mc_txn = bk->mc_txn;
2605 } else {
2606 /* Abort nested txn */
2607 *mc = *bk;
2608 if ((mx = mc->mc_xcursor) != NULL)
2609 *mx = *(MDB_xcursor *)(bk+1);
2610 }
2611 mc = bk;
2612 }
2613 /* Only malloced cursors are permanently tracked. */
2614 free(mc);
2615 }
2616 cursors[i] = NULL;
2617 }
2618 }
2619
2620 #if !(MDB_PIDLOCK) /* Currently the same as defined(_WIN32) */
2621 enum Pidlock_op {
2622 Pidset, Pidcheck
2623 };
2624 #else
2625 enum Pidlock_op {
2626 Pidset = F_SETLK, Pidcheck = F_GETLK
2627 };
2628 #endif
2629
2630 /** Set or check a pid lock. Set returns 0 on success.
2631 * Check returns 0 if the process is certainly dead, nonzero if it may
2632 * be alive (the lock exists or an error happened so we do not know).
2633 *
2634 * On Windows Pidset is a no-op, we merely check for the existence
2635 * of the process with the given pid. On POSIX we use a single byte
2636 * lock on the lockfile, set at an offset equal to the pid.
2637 */
2638 static int
mdb_reader_pid(MDB_env * env,enum Pidlock_op op,MDB_PID_T pid)2639 mdb_reader_pid(MDB_env *env, enum Pidlock_op op, MDB_PID_T pid)
2640 {
2641 #if !(MDB_PIDLOCK) /* Currently the same as defined(_WIN32) */
2642 int ret = 0;
2643 HANDLE h;
2644 if (op == Pidcheck) {
2645 h = OpenProcess(env->me_pidquery, FALSE, pid);
2646 /* No documented "no such process" code, but other program use this: */
2647 if (!h)
2648 return ErrCode() != ERROR_INVALID_PARAMETER;
2649 /* A process exists until all handles to it close. Has it exited? */
2650 ret = WaitForSingleObject(h, 0) != 0;
2651 CloseHandle(h);
2652 }
2653 return ret;
2654 #else
2655 for (;;) {
2656 int rc;
2657 struct flock lock_info;
2658 memset(&lock_info, 0, sizeof(lock_info));
2659 lock_info.l_type = F_WRLCK;
2660 lock_info.l_whence = SEEK_SET;
2661 lock_info.l_start = pid;
2662 lock_info.l_len = 1;
2663 if ((rc = fcntl(env->me_lfd, op, &lock_info)) == 0) {
2664 if (op == F_GETLK && lock_info.l_type != F_UNLCK)
2665 rc = -1;
2666 } else if ((rc = ErrCode()) == EINTR) {
2667 continue;
2668 }
2669 return rc;
2670 }
2671 #endif
2672 }
2673
2674 /** Common code for #mdb_txn_begin() and #mdb_txn_renew().
2675 * @param[in] txn the transaction handle to initialize
2676 * @return 0 on success, non-zero on failure.
2677 */
2678 static int
mdb_txn_renew0(MDB_txn * txn)2679 mdb_txn_renew0(MDB_txn *txn)
2680 {
2681 MDB_env *env = txn->mt_env;
2682 MDB_txninfo *ti = env->me_txns;
2683 MDB_meta *meta;
2684 unsigned int i, nr, flags = txn->mt_flags;
2685 uint16_t x;
2686 int rc, new_notls = 0;
2687
2688 if ((flags &= MDB_TXN_RDONLY) != 0) {
2689 if (!ti) {
2690 meta = mdb_env_pick_meta(env);
2691 txn->mt_txnid = meta->mm_txnid;
2692 txn->mt_u.reader = NULL;
2693 } else {
2694 MDB_reader *r = (env->me_flags & MDB_NOTLS) ? txn->mt_u.reader :
2695 pthread_getspecific(env->me_txkey);
2696 if (r) {
2697 if (r->mr_pid != env->me_pid || r->mr_txnid != (txnid_t)-1)
2698 return MDB_BAD_RSLOT;
2699 } else {
2700 MDB_PID_T pid = env->me_pid;
2701 MDB_THR_T tid = pthread_self();
2702 mdb_mutexref_t rmutex = env->me_rmutex;
2703
2704 if (!env->me_live_reader) {
2705 rc = mdb_reader_pid(env, Pidset, pid);
2706 if (rc)
2707 return rc;
2708 env->me_live_reader = 1;
2709 }
2710
2711 if (LOCK_MUTEX(rc, env, rmutex))
2712 return rc;
2713 nr = ti->mti_numreaders;
2714 for (i=0; i<nr; i++)
2715 if (ti->mti_readers[i].mr_pid == 0)
2716 break;
2717 if (i == env->me_maxreaders) {
2718 UNLOCK_MUTEX(rmutex);
2719 return MDB_READERS_FULL;
2720 }
2721 r = &ti->mti_readers[i];
2722 /* Claim the reader slot, carefully since other code
2723 * uses the reader table un-mutexed: First reset the
2724 * slot, next publish it in mti_numreaders. After
2725 * that, it is safe for mdb_env_close() to touch it.
2726 * When it will be closed, we can finally claim it.
2727 */
2728 r->mr_pid = 0;
2729 r->mr_txnid = (txnid_t)-1;
2730 r->mr_tid = tid;
2731 if (i == nr)
2732 ti->mti_numreaders = ++nr;
2733 env->me_close_readers = nr;
2734 r->mr_pid = pid;
2735 UNLOCK_MUTEX(rmutex);
2736
2737 new_notls = (env->me_flags & MDB_NOTLS);
2738 if (!new_notls && (rc=pthread_setspecific(env->me_txkey, r))) {
2739 r->mr_pid = 0;
2740 return rc;
2741 }
2742 }
2743 do /* LY: Retry on a race, ITS#7970. */
2744 r->mr_txnid = ti->mti_txnid;
2745 while(r->mr_txnid != ti->mti_txnid);
2746 txn->mt_txnid = r->mr_txnid;
2747 txn->mt_u.reader = r;
2748 meta = env->me_metas[txn->mt_txnid & 1];
2749 }
2750
2751 } else {
2752 /* Not yet touching txn == env->me_txn0, it may be active */
2753 if (ti) {
2754 if (LOCK_MUTEX(rc, env, env->me_wmutex))
2755 return rc;
2756 txn->mt_txnid = ti->mti_txnid;
2757 meta = env->me_metas[txn->mt_txnid & 1];
2758 } else {
2759 meta = mdb_env_pick_meta(env);
2760 txn->mt_txnid = meta->mm_txnid;
2761 }
2762 txn->mt_txnid++;
2763 #if MDB_DEBUG
2764 if (txn->mt_txnid == mdb_debug_start)
2765 mdb_debug = 1;
2766 #endif
2767 txn->mt_child = NULL;
2768 txn->mt_loose_pgs = NULL;
2769 txn->mt_loose_count = 0;
2770 txn->mt_dirty_room = MDB_IDL_UM_MAX;
2771 txn->mt_u.dirty_list = env->me_dirty_list;
2772 txn->mt_u.dirty_list[0].mid = 0;
2773 txn->mt_free_pgs = env->me_free_pgs;
2774 txn->mt_free_pgs[0] = 0;
2775 txn->mt_spill_pgs = NULL;
2776 env->me_txn = txn;
2777 memcpy(txn->mt_dbiseqs, env->me_dbiseqs, env->me_maxdbs * sizeof(unsigned int));
2778 }
2779
2780 /* Copy the DB info and flags */
2781 memcpy(txn->mt_dbs, meta->mm_dbs, CORE_DBS * sizeof(MDB_db));
2782
2783 /* Moved to here to avoid a data race in read TXNs */
2784 txn->mt_next_pgno = meta->mm_last_pg+1;
2785
2786 txn->mt_flags = flags;
2787
2788 /* Setup db info */
2789 txn->mt_numdbs = env->me_numdbs;
2790 for (i=CORE_DBS; i<txn->mt_numdbs; i++) {
2791 x = env->me_dbflags[i];
2792 txn->mt_dbs[i].md_flags = x & PERSISTENT_FLAGS;
2793 txn->mt_dbflags[i] = (x & MDB_VALID) ? DB_VALID|DB_USRVALID|DB_STALE : 0;
2794 }
2795 txn->mt_dbflags[MAIN_DBI] = DB_VALID|DB_USRVALID;
2796 txn->mt_dbflags[FREE_DBI] = DB_VALID;
2797
2798 if (env->me_flags & MDB_FATAL_ERROR) {
2799 DPUTS("environment had fatal error, must shutdown!");
2800 rc = MDB_PANIC;
2801 } else if (env->me_maxpg < txn->mt_next_pgno) {
2802 rc = MDB_MAP_RESIZED;
2803 } else {
2804 return MDB_SUCCESS;
2805 }
2806 mdb_txn_end(txn, new_notls /*0 or MDB_END_SLOT*/ | MDB_END_FAIL_BEGIN);
2807 return rc;
2808 }
2809
2810 int
mdb_txn_renew(MDB_txn * txn)2811 mdb_txn_renew(MDB_txn *txn)
2812 {
2813 int rc;
2814
2815 if (!txn || !F_ISSET(txn->mt_flags, MDB_TXN_RDONLY|MDB_TXN_FINISHED))
2816 return EINVAL;
2817
2818 rc = mdb_txn_renew0(txn);
2819 if (rc == MDB_SUCCESS) {
2820 DPRINTF(("renew txn %"Z"u%c %p on mdbenv %p, root page %"Z"u",
2821 txn->mt_txnid, (txn->mt_flags & MDB_TXN_RDONLY) ? 'r' : 'w',
2822 (void *)txn, (void *)txn->mt_env, txn->mt_dbs[MAIN_DBI].md_root));
2823 }
2824 return rc;
2825 }
2826
2827 int
mdb_txn_begin(MDB_env * env,MDB_txn * parent,unsigned int flags,MDB_txn ** ret)2828 mdb_txn_begin(MDB_env *env, MDB_txn *parent, unsigned int flags, MDB_txn **ret)
2829 {
2830 MDB_txn *txn;
2831 MDB_ntxn *ntxn;
2832 int rc, size, tsize;
2833
2834 flags &= MDB_TXN_BEGIN_FLAGS;
2835 flags |= env->me_flags & MDB_WRITEMAP;
2836
2837 if (env->me_flags & MDB_RDONLY & ~flags) /* write txn in RDONLY env */
2838 return EACCES;
2839
2840 if (parent) {
2841 /* Nested transactions: Max 1 child, write txns only, no writemap */
2842 flags |= parent->mt_flags;
2843 if (flags & (MDB_RDONLY|MDB_WRITEMAP|MDB_TXN_BLOCKED)) {
2844 return (parent->mt_flags & MDB_TXN_RDONLY) ? EINVAL : MDB_BAD_TXN;
2845 }
2846 /* Child txns save MDB_pgstate and use own copy of cursors */
2847 size = env->me_maxdbs * (sizeof(MDB_db)+sizeof(MDB_cursor *)+1);
2848 size += tsize = sizeof(MDB_ntxn);
2849 } else if (flags & MDB_RDONLY) {
2850 size = env->me_maxdbs * (sizeof(MDB_db)+1);
2851 size += tsize = sizeof(MDB_txn);
2852 } else {
2853 /* Reuse preallocated write txn. However, do not touch it until
2854 * mdb_txn_renew0() succeeds, since it currently may be active.
2855 */
2856 txn = env->me_txn0;
2857 goto renew;
2858 }
2859 if ((txn = calloc(1, size)) == NULL) {
2860 DPRINTF(("calloc: %s", strerror(errno)));
2861 return ENOMEM;
2862 }
2863 txn->mt_dbxs = env->me_dbxs; /* static */
2864 txn->mt_dbs = (MDB_db *) ((char *)txn + tsize);
2865 txn->mt_dbflags = (unsigned char *)txn + size - env->me_maxdbs;
2866 txn->mt_flags = flags;
2867 txn->mt_env = env;
2868
2869 if (parent) {
2870 unsigned int i;
2871 txn->mt_cursors = (MDB_cursor **)(txn->mt_dbs + env->me_maxdbs);
2872 txn->mt_dbiseqs = parent->mt_dbiseqs;
2873 txn->mt_u.dirty_list = malloc(sizeof(MDB_ID2)*MDB_IDL_UM_SIZE);
2874 if (!txn->mt_u.dirty_list ||
2875 !(txn->mt_free_pgs = mdb_midl_alloc(MDB_IDL_UM_MAX)))
2876 {
2877 free(txn->mt_u.dirty_list);
2878 free(txn);
2879 return ENOMEM;
2880 }
2881 txn->mt_txnid = parent->mt_txnid;
2882 txn->mt_dirty_room = parent->mt_dirty_room;
2883 txn->mt_u.dirty_list[0].mid = 0;
2884 txn->mt_spill_pgs = NULL;
2885 txn->mt_next_pgno = parent->mt_next_pgno;
2886 parent->mt_flags |= MDB_TXN_HAS_CHILD;
2887 parent->mt_child = txn;
2888 txn->mt_parent = parent;
2889 txn->mt_numdbs = parent->mt_numdbs;
2890 memcpy(txn->mt_dbs, parent->mt_dbs, txn->mt_numdbs * sizeof(MDB_db));
2891 /* Copy parent's mt_dbflags, but clear DB_NEW */
2892 for (i=0; i<txn->mt_numdbs; i++)
2893 txn->mt_dbflags[i] = parent->mt_dbflags[i] & ~DB_NEW;
2894 rc = 0;
2895 ntxn = (MDB_ntxn *)txn;
2896 ntxn->mnt_pgstate = env->me_pgstate; /* save parent me_pghead & co */
2897 if (env->me_pghead) {
2898 size = MDB_IDL_SIZEOF(env->me_pghead);
2899 env->me_pghead = mdb_midl_alloc(env->me_pghead[0]);
2900 if (env->me_pghead)
2901 memcpy(env->me_pghead, ntxn->mnt_pgstate.mf_pghead, size);
2902 else
2903 rc = ENOMEM;
2904 }
2905 if (!rc)
2906 rc = mdb_cursor_shadow(parent, txn);
2907 if (rc)
2908 mdb_txn_end(txn, MDB_END_FAIL_BEGINCHILD);
2909 } else { /* MDB_RDONLY */
2910 txn->mt_dbiseqs = env->me_dbiseqs;
2911 renew:
2912 rc = mdb_txn_renew0(txn);
2913 }
2914 if (rc) {
2915 if (txn != env->me_txn0)
2916 free(txn);
2917 } else {
2918 txn->mt_flags |= flags; /* could not change txn=me_txn0 earlier */
2919 *ret = txn;
2920 DPRINTF(("begin txn %"Z"u%c %p on mdbenv %p, root page %"Z"u",
2921 txn->mt_txnid, (flags & MDB_RDONLY) ? 'r' : 'w',
2922 (void *) txn, (void *) env, txn->mt_dbs[MAIN_DBI].md_root));
2923 }
2924
2925 return rc;
2926 }
2927
2928 MDB_env *
mdb_txn_env(MDB_txn * txn)2929 mdb_txn_env(MDB_txn *txn)
2930 {
2931 if(!txn) return NULL;
2932 return txn->mt_env;
2933 }
2934
2935 size_t
mdb_txn_id(MDB_txn * txn)2936 mdb_txn_id(MDB_txn *txn)
2937 {
2938 if(!txn) return 0;
2939 return txn->mt_txnid;
2940 }
2941
2942 /** Export or close DBI handles opened in this txn. */
2943 static void
mdb_dbis_update(MDB_txn * txn,int keep)2944 mdb_dbis_update(MDB_txn *txn, int keep)
2945 {
2946 int i;
2947 MDB_dbi n = txn->mt_numdbs;
2948 MDB_env *env = txn->mt_env;
2949 unsigned char *tdbflags = txn->mt_dbflags;
2950
2951 for (i = n; --i >= CORE_DBS;) {
2952 if (tdbflags[i] & DB_NEW) {
2953 if (keep) {
2954 env->me_dbflags[i] = txn->mt_dbs[i].md_flags | MDB_VALID;
2955 } else {
2956 char *ptr = env->me_dbxs[i].md_name.mv_data;
2957 if (ptr) {
2958 env->me_dbxs[i].md_name.mv_data = NULL;
2959 env->me_dbxs[i].md_name.mv_size = 0;
2960 env->me_dbflags[i] = 0;
2961 env->me_dbiseqs[i]++;
2962 free(ptr);
2963 }
2964 }
2965 }
2966 }
2967 if (keep && env->me_numdbs < n)
2968 env->me_numdbs = n;
2969 }
2970
2971 /** End a transaction, except successful commit of a nested transaction.
2972 * May be called twice for readonly txns: First reset it, then abort.
2973 * @param[in] txn the transaction handle to end
2974 * @param[in] mode why and how to end the transaction
2975 */
2976 static void
mdb_txn_end(MDB_txn * txn,unsigned mode)2977 mdb_txn_end(MDB_txn *txn, unsigned mode)
2978 {
2979 MDB_env *env = txn->mt_env;
2980 #if MDB_DEBUG
2981 static const char *const names[] = MDB_END_NAMES;
2982 #endif
2983
2984 /* Export or close DBI handles opened in this txn */
2985 mdb_dbis_update(txn, mode & MDB_END_UPDATE);
2986
2987 DPRINTF(("%s txn %"Z"u%c %p on mdbenv %p, root page %"Z"u",
2988 names[mode & MDB_END_OPMASK],
2989 txn->mt_txnid, (txn->mt_flags & MDB_TXN_RDONLY) ? 'r' : 'w',
2990 (void *) txn, (void *)env, txn->mt_dbs[MAIN_DBI].md_root));
2991
2992 if (F_ISSET(txn->mt_flags, MDB_TXN_RDONLY)) {
2993 if (txn->mt_u.reader) {
2994 txn->mt_u.reader->mr_txnid = (txnid_t)-1;
2995 if (!(env->me_flags & MDB_NOTLS)) {
2996 txn->mt_u.reader = NULL; /* txn does not own reader */
2997 } else if (mode & MDB_END_SLOT) {
2998 txn->mt_u.reader->mr_pid = 0;
2999 txn->mt_u.reader = NULL;
3000 } /* else txn owns the slot until it does MDB_END_SLOT */
3001 }
3002 txn->mt_numdbs = 0; /* prevent further DBI activity */
3003 txn->mt_flags |= MDB_TXN_FINISHED;
3004
3005 } else if (!F_ISSET(txn->mt_flags, MDB_TXN_FINISHED)) {
3006 pgno_t *pghead = env->me_pghead;
3007
3008 if (!(mode & MDB_END_UPDATE)) /* !(already closed cursors) */
3009 mdb_cursors_close(txn, 0);
3010 if (!(env->me_flags & MDB_WRITEMAP)) {
3011 mdb_dlist_free(txn);
3012 }
3013
3014 txn->mt_numdbs = 0;
3015 txn->mt_flags = MDB_TXN_FINISHED;
3016
3017 if (!txn->mt_parent) {
3018 mdb_midl_shrink(&txn->mt_free_pgs);
3019 env->me_free_pgs = txn->mt_free_pgs;
3020 /* me_pgstate: */
3021 env->me_pghead = NULL;
3022 env->me_pglast = 0;
3023
3024 env->me_txn = NULL;
3025 mode = 0; /* txn == env->me_txn0, do not free() it */
3026
3027 /* The writer mutex was locked in mdb_txn_begin. */
3028 if (env->me_txns)
3029 UNLOCK_MUTEX(env->me_wmutex);
3030 } else {
3031 txn->mt_parent->mt_child = NULL;
3032 txn->mt_parent->mt_flags &= ~MDB_TXN_HAS_CHILD;
3033 env->me_pgstate = ((MDB_ntxn *)txn)->mnt_pgstate;
3034 mdb_midl_free(txn->mt_free_pgs);
3035 free(txn->mt_u.dirty_list);
3036 }
3037 mdb_midl_free(txn->mt_spill_pgs);
3038
3039 mdb_midl_free(pghead);
3040 }
3041
3042 if (mode & MDB_END_FREE)
3043 free(txn);
3044 }
3045
3046 void
mdb_txn_reset(MDB_txn * txn)3047 mdb_txn_reset(MDB_txn *txn)
3048 {
3049 if (txn == NULL)
3050 return;
3051
3052 /* This call is only valid for read-only txns */
3053 if (!(txn->mt_flags & MDB_TXN_RDONLY))
3054 return;
3055
3056 mdb_txn_end(txn, MDB_END_RESET);
3057 }
3058
3059 void
mdb_txn_abort(MDB_txn * txn)3060 mdb_txn_abort(MDB_txn *txn)
3061 {
3062 if (txn == NULL)
3063 return;
3064
3065 if (txn->mt_child)
3066 mdb_txn_abort(txn->mt_child);
3067
3068 mdb_txn_end(txn, MDB_END_ABORT|MDB_END_SLOT|MDB_END_FREE);
3069 }
3070
3071 /** Save the freelist as of this transaction to the freeDB.
3072 * This changes the freelist. Keep trying until it stabilizes.
3073 */
3074 static int
mdb_freelist_save(MDB_txn * txn)3075 mdb_freelist_save(MDB_txn *txn)
3076 {
3077 /* env->me_pghead[] can grow and shrink during this call.
3078 * env->me_pglast and txn->mt_free_pgs[] can only grow.
3079 * Page numbers cannot disappear from txn->mt_free_pgs[].
3080 */
3081 MDB_cursor mc;
3082 MDB_env *env = txn->mt_env;
3083 int rc, maxfree_1pg = env->me_maxfree_1pg, more = 1;
3084 txnid_t pglast = 0, head_id = 0;
3085 pgno_t freecnt = 0, *free_pgs, *mop;
3086 ssize_t head_room = 0, total_room = 0, mop_len, clean_limit;
3087
3088 mdb_cursor_init(&mc, txn, FREE_DBI, NULL);
3089
3090 if (env->me_pghead) {
3091 /* Make sure first page of freeDB is touched and on freelist */
3092 rc = mdb_page_search(&mc, NULL, MDB_PS_FIRST|MDB_PS_MODIFY);
3093 if (rc && rc != MDB_NOTFOUND)
3094 return rc;
3095 }
3096
3097 if (!env->me_pghead && txn->mt_loose_pgs) {
3098 /* Put loose page numbers in mt_free_pgs, since
3099 * we may be unable to return them to me_pghead.
3100 */
3101 MDB_page *mp = txn->mt_loose_pgs;
3102 MDB_ID2 *dl = txn->mt_u.dirty_list;
3103 unsigned x;
3104 if ((rc = mdb_midl_need(&txn->mt_free_pgs, txn->mt_loose_count)) != 0)
3105 return rc;
3106 for (; mp; mp = NEXT_LOOSE_PAGE(mp)) {
3107 mdb_midl_xappend(txn->mt_free_pgs, mp->mp_pgno);
3108 /* must also remove from dirty list */
3109 if (txn->mt_flags & MDB_TXN_WRITEMAP) {
3110 for (x=1; x<=dl[0].mid; x++)
3111 if (dl[x].mid == mp->mp_pgno)
3112 break;
3113 mdb_tassert(txn, x <= dl[0].mid);
3114 } else {
3115 x = mdb_mid2l_search(dl, mp->mp_pgno);
3116 mdb_tassert(txn, dl[x].mid == mp->mp_pgno);
3117 mdb_dpage_free(env, mp);
3118 }
3119 dl[x].mptr = NULL;
3120 }
3121 {
3122 /* squash freed slots out of the dirty list */
3123 unsigned y;
3124 for (y=1; dl[y].mptr && y <= dl[0].mid; y++);
3125 if (y <= dl[0].mid) {
3126 for(x=y, y++;;) {
3127 while (!dl[y].mptr && y <= dl[0].mid) y++;
3128 if (y > dl[0].mid) break;
3129 dl[x++] = dl[y++];
3130 }
3131 dl[0].mid = x-1;
3132 } else {
3133 /* all slots freed */
3134 dl[0].mid = 0;
3135 }
3136 }
3137 txn->mt_loose_pgs = NULL;
3138 txn->mt_loose_count = 0;
3139 }
3140
3141 /* MDB_RESERVE cancels meminit in ovpage malloc (when no WRITEMAP) */
3142 clean_limit = (env->me_flags & (MDB_NOMEMINIT|MDB_WRITEMAP))
3143 ? SSIZE_MAX : maxfree_1pg;
3144
3145 for (;;) {
3146 /* Come back here after each Put() in case freelist changed */
3147 MDB_val key, data;
3148 pgno_t *pgs;
3149 ssize_t j;
3150
3151 /* If using records from freeDB which we have not yet
3152 * deleted, delete them and any we reserved for me_pghead.
3153 */
3154 while (pglast < env->me_pglast) {
3155 rc = mdb_cursor_first(&mc, &key, NULL);
3156 if (rc)
3157 return rc;
3158 pglast = head_id = *(txnid_t *)key.mv_data;
3159 total_room = head_room = 0;
3160 mdb_tassert(txn, pglast <= env->me_pglast);
3161 rc = mdb_cursor_del(&mc, 0);
3162 if (rc)
3163 return rc;
3164 }
3165
3166 /* Save the IDL of pages freed by this txn, to a single record */
3167 if (freecnt < txn->mt_free_pgs[0]) {
3168 if (!freecnt) {
3169 /* Make sure last page of freeDB is touched and on freelist */
3170 rc = mdb_page_search(&mc, NULL, MDB_PS_LAST|MDB_PS_MODIFY);
3171 if (rc && rc != MDB_NOTFOUND)
3172 return rc;
3173 }
3174 free_pgs = txn->mt_free_pgs;
3175 /* Write to last page of freeDB */
3176 key.mv_size = sizeof(txn->mt_txnid);
3177 key.mv_data = &txn->mt_txnid;
3178 do {
3179 freecnt = free_pgs[0];
3180 data.mv_size = MDB_IDL_SIZEOF(free_pgs);
3181 rc = mdb_cursor_put(&mc, &key, &data, MDB_RESERVE);
3182 if (rc)
3183 return rc;
3184 /* Retry if mt_free_pgs[] grew during the Put() */
3185 free_pgs = txn->mt_free_pgs;
3186 } while (freecnt < free_pgs[0]);
3187 mdb_midl_sort(free_pgs);
3188 memcpy(data.mv_data, free_pgs, data.mv_size);
3189 #if (MDB_DEBUG) > 1
3190 {
3191 unsigned int i = free_pgs[0];
3192 DPRINTF(("IDL write txn %"Z"u root %"Z"u num %u",
3193 txn->mt_txnid, txn->mt_dbs[FREE_DBI].md_root, i));
3194 for (; i; i--)
3195 DPRINTF(("IDL %"Z"u", free_pgs[i]));
3196 }
3197 #endif
3198 continue;
3199 }
3200
3201 mop = env->me_pghead;
3202 mop_len = (mop ? mop[0] : 0) + txn->mt_loose_count;
3203
3204 /* Reserve records for me_pghead[]. Split it if multi-page,
3205 * to avoid searching freeDB for a page range. Use keys in
3206 * range [1,me_pglast]: Smaller than txnid of oldest reader.
3207 */
3208 if (total_room >= mop_len) {
3209 if (total_room == mop_len || --more < 0)
3210 break;
3211 } else if (head_room >= maxfree_1pg && head_id > 1) {
3212 /* Keep current record (overflow page), add a new one */
3213 head_id--;
3214 head_room = 0;
3215 }
3216 /* (Re)write {key = head_id, IDL length = head_room} */
3217 total_room -= head_room;
3218 head_room = mop_len - total_room;
3219 if (head_room > maxfree_1pg && head_id > 1) {
3220 /* Overflow multi-page for part of me_pghead */
3221 head_room /= head_id; /* amortize page sizes */
3222 head_room += maxfree_1pg - head_room % (maxfree_1pg + 1);
3223 } else if (head_room < 0) {
3224 /* Rare case, not bothering to delete this record */
3225 head_room = 0;
3226 }
3227 key.mv_size = sizeof(head_id);
3228 key.mv_data = &head_id;
3229 data.mv_size = (head_room + 1) * sizeof(pgno_t);
3230 rc = mdb_cursor_put(&mc, &key, &data, MDB_RESERVE);
3231 if (rc)
3232 return rc;
3233 /* IDL is initially empty, zero out at least the length */
3234 pgs = (pgno_t *)data.mv_data;
3235 j = head_room > clean_limit ? head_room : 0;
3236 do {
3237 pgs[j] = 0;
3238 } while (--j >= 0);
3239 total_room += head_room;
3240 }
3241
3242 /* Return loose page numbers to me_pghead, though usually none are
3243 * left at this point. The pages themselves remain in dirty_list.
3244 */
3245 if (txn->mt_loose_pgs) {
3246 MDB_page *mp = txn->mt_loose_pgs;
3247 unsigned count = txn->mt_loose_count;
3248 MDB_IDL loose;
3249 /* Room for loose pages + temp IDL with same */
3250 if ((rc = mdb_midl_need(&env->me_pghead, 2*count+1)) != 0)
3251 return rc;
3252 mop = env->me_pghead;
3253 loose = mop + MDB_IDL_ALLOCLEN(mop) - count;
3254 for (count = 0; mp; mp = NEXT_LOOSE_PAGE(mp))
3255 loose[ ++count ] = mp->mp_pgno;
3256 loose[0] = count;
3257 mdb_midl_sort(loose);
3258 mdb_midl_xmerge(mop, loose);
3259 txn->mt_loose_pgs = NULL;
3260 txn->mt_loose_count = 0;
3261 mop_len = mop[0];
3262 }
3263
3264 /* Fill in the reserved me_pghead records */
3265 rc = MDB_SUCCESS;
3266 if (mop_len) {
3267 MDB_val key, data;
3268
3269 mop += mop_len;
3270 rc = mdb_cursor_first(&mc, &key, &data);
3271 for (; !rc; rc = mdb_cursor_next(&mc, &key, &data, MDB_NEXT)) {
3272 txnid_t id = *(txnid_t *)key.mv_data;
3273 ssize_t len = (ssize_t)(data.mv_size / sizeof(MDB_ID)) - 1;
3274 MDB_ID save;
3275
3276 mdb_tassert(txn, len >= 0 && id <= env->me_pglast);
3277 key.mv_data = &id;
3278 if (len > mop_len) {
3279 len = mop_len;
3280 data.mv_size = (len + 1) * sizeof(MDB_ID);
3281 }
3282 data.mv_data = mop -= len;
3283 save = mop[0];
3284 mop[0] = len;
3285 rc = mdb_cursor_put(&mc, &key, &data, MDB_CURRENT);
3286 mop[0] = save;
3287 if (rc || !(mop_len -= len))
3288 break;
3289 }
3290 }
3291 return rc;
3292 }
3293
3294 /** Flush (some) dirty pages to the map, after clearing their dirty flag.
3295 * @param[in] txn the transaction that's being committed
3296 * @param[in] keep number of initial pages in dirty_list to keep dirty.
3297 * @return 0 on success, non-zero on failure.
3298 */
3299 static int
mdb_page_flush(MDB_txn * txn,int keep)3300 mdb_page_flush(MDB_txn *txn, int keep)
3301 {
3302 MDB_env *env = txn->mt_env;
3303 MDB_ID2L dl = txn->mt_u.dirty_list;
3304 unsigned psize = env->me_psize, j;
3305 int i, pagecount = dl[0].mid, rc;
3306 size_t size = 0, pos = 0;
3307 pgno_t pgno = 0;
3308 MDB_page *dp = NULL;
3309 #ifdef _WIN32
3310 OVERLAPPED ov;
3311 #else
3312 struct iovec iov[MDB_COMMIT_PAGES];
3313 ssize_t wpos = 0, wsize = 0, wres;
3314 size_t next_pos = 1; /* impossible pos, so pos != next_pos */
3315 int n = 0;
3316 #endif
3317
3318 j = i = keep;
3319
3320 if (env->me_flags & MDB_WRITEMAP) {
3321 /* Clear dirty flags */
3322 while (++i <= pagecount) {
3323 dp = dl[i].mptr;
3324 /* Don't flush this page yet */
3325 if (dp->mp_flags & (P_LOOSE|P_KEEP)) {
3326 dp->mp_flags &= ~P_KEEP;
3327 dl[++j] = dl[i];
3328 continue;
3329 }
3330 dp->mp_flags &= ~P_DIRTY;
3331 }
3332 goto done;
3333 }
3334
3335 /* Write the pages */
3336 for (;;) {
3337 if (++i <= pagecount) {
3338 dp = dl[i].mptr;
3339 /* Don't flush this page yet */
3340 if (dp->mp_flags & (P_LOOSE|P_KEEP)) {
3341 dp->mp_flags &= ~P_KEEP;
3342 dl[i].mid = 0;
3343 continue;
3344 }
3345 pgno = dl[i].mid;
3346 /* clear dirty flag */
3347 dp->mp_flags &= ~P_DIRTY;
3348 pos = pgno * psize;
3349 size = psize;
3350 if (IS_OVERFLOW(dp)) size *= dp->mp_pages;
3351 }
3352 #ifdef _WIN32
3353 else break;
3354
3355 /* Windows actually supports scatter/gather I/O, but only on
3356 * unbuffered file handles. Since we're relying on the OS page
3357 * cache for all our data, that's self-defeating. So we just
3358 * write pages one at a time. We use the ov structure to set
3359 * the write offset, to at least save the overhead of a Seek
3360 * system call.
3361 */
3362 DPRINTF(("committing page %"Z"u", pgno));
3363 memset(&ov, 0, sizeof(ov));
3364 ov.Offset = pos & 0xffffffff;
3365 ov.OffsetHigh = pos >> 16 >> 16;
3366 if (!WriteFile(env->me_fd, dp, size, NULL, &ov)) {
3367 rc = ErrCode();
3368 DPRINTF(("WriteFile: %d", rc));
3369 return rc;
3370 }
3371 #else
3372 /* Write up to MDB_COMMIT_PAGES dirty pages at a time. */
3373 if (pos!=next_pos || n==MDB_COMMIT_PAGES || wsize+size>MAX_WRITE) {
3374 if (n) {
3375 retry_write:
3376 /* Write previous page(s) */
3377 #ifdef MDB_USE_PWRITEV
3378 wres = pwritev(env->me_fd, iov, n, wpos);
3379 #else
3380 if (n == 1) {
3381 wres = pwrite(env->me_fd, iov[0].iov_base, wsize, wpos);
3382 } else {
3383 retry_seek:
3384 if (lseek(env->me_fd, wpos, SEEK_SET) == -1) {
3385 rc = ErrCode();
3386 if (rc == EINTR)
3387 goto retry_seek;
3388 DPRINTF(("lseek: %s", strerror(rc)));
3389 return rc;
3390 }
3391 wres = writev(env->me_fd, iov, n);
3392 }
3393 #endif
3394 if (wres != wsize) {
3395 if (wres < 0) {
3396 rc = ErrCode();
3397 if (rc == EINTR)
3398 goto retry_write;
3399 DPRINTF(("Write error: %s", strerror(rc)));
3400 } else {
3401 rc = EIO; /* TODO: Use which error code? */
3402 DPUTS("short write, filesystem full?");
3403 }
3404 return rc;
3405 }
3406 n = 0;
3407 }
3408 if (i > pagecount)
3409 break;
3410 wpos = pos;
3411 wsize = 0;
3412 }
3413 DPRINTF(("committing page %"Z"u", pgno));
3414 next_pos = pos + size;
3415 iov[n].iov_len = size;
3416 iov[n].iov_base = (char *)dp;
3417 wsize += size;
3418 n++;
3419 #endif /* _WIN32 */
3420 }
3421
3422 /* MIPS has cache coherency issues, this is a no-op everywhere else
3423 * Note: for any size >= on-chip cache size, entire on-chip cache is
3424 * flushed.
3425 */
3426 CACHEFLUSH(env->me_map, txn->mt_next_pgno * env->me_psize, DCACHE);
3427
3428 for (i = keep; ++i <= pagecount; ) {
3429 dp = dl[i].mptr;
3430 /* This is a page we skipped above */
3431 if (!dl[i].mid) {
3432 dl[++j] = dl[i];
3433 dl[j].mid = dp->mp_pgno;
3434 continue;
3435 }
3436 mdb_dpage_free(env, dp);
3437 }
3438
3439 done:
3440 i--;
3441 txn->mt_dirty_room += i - j;
3442 dl[0].mid = j;
3443 return MDB_SUCCESS;
3444 }
3445
3446 int
mdb_txn_commit(MDB_txn * txn)3447 mdb_txn_commit(MDB_txn *txn)
3448 {
3449 int rc;
3450 unsigned int i, end_mode;
3451 MDB_env *env;
3452
3453 if (txn == NULL)
3454 return EINVAL;
3455
3456 /* mdb_txn_end() mode for a commit which writes nothing */
3457 end_mode = MDB_END_EMPTY_COMMIT|MDB_END_UPDATE|MDB_END_SLOT|MDB_END_FREE;
3458
3459 if (txn->mt_child) {
3460 rc = mdb_txn_commit(txn->mt_child);
3461 if (rc)
3462 goto fail;
3463 }
3464
3465 env = txn->mt_env;
3466
3467 if (F_ISSET(txn->mt_flags, MDB_TXN_RDONLY)) {
3468 goto done;
3469 }
3470
3471 if (txn->mt_flags & (MDB_TXN_FINISHED|MDB_TXN_ERROR)) {
3472 DPUTS("txn has failed/finished, can't commit");
3473 if (txn->mt_parent)
3474 txn->mt_parent->mt_flags |= MDB_TXN_ERROR;
3475 rc = MDB_BAD_TXN;
3476 goto fail;
3477 }
3478
3479 if (txn->mt_parent) {
3480 MDB_txn *parent = txn->mt_parent;
3481 MDB_page **lp;
3482 MDB_ID2L dst, src;
3483 MDB_IDL pspill;
3484 unsigned x, y, len, ps_len;
3485
3486 /* Append our free list to parent's */
3487 rc = mdb_midl_append_list(&parent->mt_free_pgs, txn->mt_free_pgs);
3488 if (rc)
3489 goto fail;
3490 mdb_midl_free(txn->mt_free_pgs);
3491 /* Failures after this must either undo the changes
3492 * to the parent or set MDB_TXN_ERROR in the parent.
3493 */
3494
3495 parent->mt_next_pgno = txn->mt_next_pgno;
3496 parent->mt_flags = txn->mt_flags;
3497
3498 /* Merge our cursors into parent's and close them */
3499 mdb_cursors_close(txn, 1);
3500
3501 /* Update parent's DB table. */
3502 memcpy(parent->mt_dbs, txn->mt_dbs, txn->mt_numdbs * sizeof(MDB_db));
3503 parent->mt_numdbs = txn->mt_numdbs;
3504 parent->mt_dbflags[FREE_DBI] = txn->mt_dbflags[FREE_DBI];
3505 parent->mt_dbflags[MAIN_DBI] = txn->mt_dbflags[MAIN_DBI];
3506 for (i=CORE_DBS; i<txn->mt_numdbs; i++) {
3507 /* preserve parent's DB_NEW status */
3508 x = parent->mt_dbflags[i] & DB_NEW;
3509 parent->mt_dbflags[i] = txn->mt_dbflags[i] | x;
3510 }
3511
3512 dst = parent->mt_u.dirty_list;
3513 src = txn->mt_u.dirty_list;
3514 /* Remove anything in our dirty list from parent's spill list */
3515 if ((pspill = parent->mt_spill_pgs) && (ps_len = pspill[0])) {
3516 x = y = ps_len;
3517 pspill[0] = (pgno_t)-1;
3518 /* Mark our dirty pages as deleted in parent spill list */
3519 for (i=0, len=src[0].mid; ++i <= len; ) {
3520 MDB_ID pn = src[i].mid << 1;
3521 while (pn > pspill[x])
3522 x--;
3523 if (pn == pspill[x]) {
3524 pspill[x] = 1;
3525 y = --x;
3526 }
3527 }
3528 /* Squash deleted pagenums if we deleted any */
3529 for (x=y; ++x <= ps_len; )
3530 if (!(pspill[x] & 1))
3531 pspill[++y] = pspill[x];
3532 pspill[0] = y;
3533 }
3534
3535 /* Remove anything in our spill list from parent's dirty list */
3536 if (txn->mt_spill_pgs && txn->mt_spill_pgs[0]) {
3537 for (i=1; i<=txn->mt_spill_pgs[0]; i++) {
3538 MDB_ID pn = txn->mt_spill_pgs[i];
3539 if (pn & 1)
3540 continue; /* deleted spillpg */
3541 pn >>= 1;
3542 y = mdb_mid2l_search(dst, pn);
3543 if (y <= dst[0].mid && dst[y].mid == pn) {
3544 free(dst[y].mptr);
3545 while (y < dst[0].mid) {
3546 dst[y] = dst[y+1];
3547 y++;
3548 }
3549 dst[0].mid--;
3550 }
3551 }
3552 }
3553
3554 /* Find len = length of merging our dirty list with parent's */
3555 x = dst[0].mid;
3556 dst[0].mid = 0; /* simplify loops */
3557 if (parent->mt_parent) {
3558 len = x + src[0].mid;
3559 y = mdb_mid2l_search(src, dst[x].mid + 1) - 1;
3560 for (i = x; y && i; y--) {
3561 pgno_t yp = src[y].mid;
3562 while (yp < dst[i].mid)
3563 i--;
3564 if (yp == dst[i].mid) {
3565 i--;
3566 len--;
3567 }
3568 }
3569 } else { /* Simplify the above for single-ancestor case */
3570 len = MDB_IDL_UM_MAX - txn->mt_dirty_room;
3571 }
3572 /* Merge our dirty list with parent's */
3573 y = src[0].mid;
3574 for (i = len; y; dst[i--] = src[y--]) {
3575 pgno_t yp = src[y].mid;
3576 while (yp < dst[x].mid)
3577 dst[i--] = dst[x--];
3578 if (yp == dst[x].mid)
3579 free(dst[x--].mptr);
3580 }
3581 mdb_tassert(txn, i == x);
3582 dst[0].mid = len;
3583 free(txn->mt_u.dirty_list);
3584 parent->mt_dirty_room = txn->mt_dirty_room;
3585 if (txn->mt_spill_pgs) {
3586 if (parent->mt_spill_pgs) {
3587 /* TODO: Prevent failure here, so parent does not fail */
3588 rc = mdb_midl_append_list(&parent->mt_spill_pgs, txn->mt_spill_pgs);
3589 if (rc)
3590 parent->mt_flags |= MDB_TXN_ERROR;
3591 mdb_midl_free(txn->mt_spill_pgs);
3592 mdb_midl_sort(parent->mt_spill_pgs);
3593 } else {
3594 parent->mt_spill_pgs = txn->mt_spill_pgs;
3595 }
3596 }
3597
3598 /* Append our loose page list to parent's */
3599 for (lp = &parent->mt_loose_pgs; *lp; lp = &NEXT_LOOSE_PAGE(*lp))
3600 ;
3601 *lp = txn->mt_loose_pgs;
3602 parent->mt_loose_count += txn->mt_loose_count;
3603
3604 parent->mt_child = NULL;
3605 mdb_midl_free(((MDB_ntxn *)txn)->mnt_pgstate.mf_pghead);
3606 free(txn);
3607 return rc;
3608 }
3609
3610 if (txn != env->me_txn) {
3611 DPUTS("attempt to commit unknown transaction");
3612 rc = EINVAL;
3613 goto fail;
3614 }
3615
3616 mdb_cursors_close(txn, 0);
3617
3618 if (!txn->mt_u.dirty_list[0].mid &&
3619 !(txn->mt_flags & (MDB_TXN_DIRTY|MDB_TXN_SPILLS)))
3620 goto done;
3621
3622 DPRINTF(("committing txn %"Z"u %p on mdbenv %p, root page %"Z"u",
3623 txn->mt_txnid, (void*)txn, (void*)env, txn->mt_dbs[MAIN_DBI].md_root));
3624
3625 /* Update DB root pointers */
3626 if (txn->mt_numdbs > CORE_DBS) {
3627 MDB_cursor mc;
3628 MDB_dbi i;
3629 MDB_val data;
3630 data.mv_size = sizeof(MDB_db);
3631
3632 mdb_cursor_init(&mc, txn, MAIN_DBI, NULL);
3633 for (i = CORE_DBS; i < txn->mt_numdbs; i++) {
3634 if (txn->mt_dbflags[i] & DB_DIRTY) {
3635 if (TXN_DBI_CHANGED(txn, i)) {
3636 rc = MDB_BAD_DBI;
3637 goto fail;
3638 }
3639 data.mv_data = &txn->mt_dbs[i];
3640 rc = mdb_cursor_put(&mc, &txn->mt_dbxs[i].md_name, &data,
3641 F_SUBDATA);
3642 if (rc)
3643 goto fail;
3644 }
3645 }
3646 }
3647
3648 rc = mdb_freelist_save(txn);
3649 if (rc)
3650 goto fail;
3651
3652 mdb_midl_free(env->me_pghead);
3653 env->me_pghead = NULL;
3654 mdb_midl_shrink(&txn->mt_free_pgs);
3655
3656 #if (MDB_DEBUG) > 2
3657 mdb_audit(txn);
3658 #endif
3659
3660 if ((rc = mdb_page_flush(txn, 0)) ||
3661 (rc = mdb_env_sync(env, 0)) ||
3662 (rc = mdb_env_write_meta(txn)))
3663 goto fail;
3664 end_mode = MDB_END_COMMITTED|MDB_END_UPDATE;
3665
3666 done:
3667 mdb_txn_end(txn, end_mode);
3668 return MDB_SUCCESS;
3669
3670 fail:
3671 mdb_txn_abort(txn);
3672 return rc;
3673 }
3674
3675 /** Read the environment parameters of a DB environment before
3676 * mapping it into memory.
3677 * @param[in] env the environment handle
3678 * @param[out] meta address of where to store the meta information
3679 * @return 0 on success, non-zero on failure.
3680 */
3681 static int ESECT
mdb_env_read_header(MDB_env * env,MDB_meta * meta)3682 mdb_env_read_header(MDB_env *env, MDB_meta *meta)
3683 {
3684 MDB_metabuf pbuf;
3685 MDB_page *p;
3686 MDB_meta *m;
3687 int i, rc, off;
3688 enum { Size = sizeof(pbuf) };
3689
3690 /* We don't know the page size yet, so use a minimum value.
3691 * Read both meta pages so we can use the latest one.
3692 */
3693
3694 for (i=off=0; i<NUM_METAS; i++, off += meta->mm_psize) {
3695 #ifdef _WIN32
3696 DWORD len;
3697 OVERLAPPED ov;
3698 memset(&ov, 0, sizeof(ov));
3699 ov.Offset = off;
3700 rc = ReadFile(env->me_fd, &pbuf, Size, &len, &ov) ? (int)len : -1;
3701 if (rc == -1 && ErrCode() == ERROR_HANDLE_EOF)
3702 rc = 0;
3703 #else
3704 rc = pread(env->me_fd, &pbuf, Size, off);
3705 #endif
3706 if (rc != Size) {
3707 if (rc == 0 && off == 0)
3708 return ENOENT;
3709 rc = rc < 0 ? (int) ErrCode() : MDB_INVALID;
3710 DPRINTF(("read: %s", mdb_strerror(rc)));
3711 return rc;
3712 }
3713
3714 p = (MDB_page *)&pbuf;
3715
3716 if (!F_ISSET(p->mp_flags, P_META)) {
3717 DPRINTF(("page %"Z"u not a meta page", p->mp_pgno));
3718 return MDB_INVALID;
3719 }
3720
3721 m = METADATA(p);
3722 if (m->mm_magic != MDB_MAGIC) {
3723 DPUTS("meta has invalid magic");
3724 return MDB_INVALID;
3725 }
3726
3727 if (m->mm_version != MDB_DATA_VERSION) {
3728 DPRINTF(("database is version %u, expected version %u",
3729 m->mm_version, MDB_DATA_VERSION));
3730 return MDB_VERSION_MISMATCH;
3731 }
3732
3733 if (off == 0 || m->mm_txnid > meta->mm_txnid)
3734 *meta = *m;
3735 }
3736 return 0;
3737 }
3738
3739 /** Fill in most of the zeroed #MDB_meta for an empty database environment */
3740 static void ESECT
mdb_env_init_meta0(MDB_env * env,MDB_meta * meta)3741 mdb_env_init_meta0(MDB_env *env, MDB_meta *meta)
3742 {
3743 meta->mm_magic = MDB_MAGIC;
3744 meta->mm_version = MDB_DATA_VERSION;
3745 meta->mm_mapsize = env->me_mapsize;
3746 meta->mm_psize = env->me_psize;
3747 meta->mm_last_pg = NUM_METAS-1;
3748 meta->mm_flags = env->me_flags & 0xffff;
3749 meta->mm_flags |= MDB_INTEGERKEY; /* this is mm_dbs[FREE_DBI].md_flags */
3750 meta->mm_dbs[FREE_DBI].md_root = P_INVALID;
3751 meta->mm_dbs[MAIN_DBI].md_root = P_INVALID;
3752 }
3753
3754 /** Write the environment parameters of a freshly created DB environment.
3755 * @param[in] env the environment handle
3756 * @param[in] meta the #MDB_meta to write
3757 * @return 0 on success, non-zero on failure.
3758 */
3759 static int ESECT
mdb_env_init_meta(MDB_env * env,MDB_meta * meta)3760 mdb_env_init_meta(MDB_env *env, MDB_meta *meta)
3761 {
3762 MDB_page *p, *q;
3763 int rc;
3764 unsigned int psize;
3765 #ifdef _WIN32
3766 DWORD len;
3767 OVERLAPPED ov;
3768 memset(&ov, 0, sizeof(ov));
3769 #define DO_PWRITE(rc, fd, ptr, size, len, pos) do { \
3770 ov.Offset = pos; \
3771 rc = WriteFile(fd, ptr, size, &len, &ov); } while(0)
3772 #else
3773 int len;
3774 #define DO_PWRITE(rc, fd, ptr, size, len, pos) do { \
3775 len = pwrite(fd, ptr, size, pos); \
3776 if (len == -1 && ErrCode() == EINTR) continue; \
3777 rc = (len >= 0); break; } while(1)
3778 #endif
3779
3780 DPUTS("writing new meta page");
3781
3782 psize = env->me_psize;
3783
3784 p = calloc(NUM_METAS, psize);
3785 if (!p)
3786 return ENOMEM;
3787
3788 p->mp_pgno = 0;
3789 p->mp_flags = P_META;
3790 *(MDB_meta *)METADATA(p) = *meta;
3791
3792 q = (MDB_page *)((char *)p + psize);
3793 q->mp_pgno = 1;
3794 q->mp_flags = P_META;
3795 *(MDB_meta *)METADATA(q) = *meta;
3796
3797 DO_PWRITE(rc, env->me_fd, p, psize * NUM_METAS, len, 0);
3798 if (!rc)
3799 rc = ErrCode();
3800 else if ((unsigned) len == psize * NUM_METAS)
3801 rc = MDB_SUCCESS;
3802 else
3803 rc = ENOSPC;
3804 free(p);
3805 return rc;
3806 }
3807
3808 /** Update the environment info to commit a transaction.
3809 * @param[in] txn the transaction that's being committed
3810 * @return 0 on success, non-zero on failure.
3811 */
3812 static int
mdb_env_write_meta(MDB_txn * txn)3813 mdb_env_write_meta(MDB_txn *txn)
3814 {
3815 MDB_env *env;
3816 MDB_meta meta, metab, *mp;
3817 unsigned flags;
3818 size_t mapsize;
3819 off_t off;
3820 int rc, len, toggle;
3821 char *ptr;
3822 HANDLE mfd;
3823 #ifdef _WIN32
3824 OVERLAPPED ov;
3825 #else
3826 int r2;
3827 #endif
3828
3829 toggle = txn->mt_txnid & 1;
3830 DPRINTF(("writing meta page %d for root page %"Z"u",
3831 toggle, txn->mt_dbs[MAIN_DBI].md_root));
3832
3833 env = txn->mt_env;
3834 flags = env->me_flags;
3835 mp = env->me_metas[toggle];
3836 mapsize = env->me_metas[toggle ^ 1]->mm_mapsize;
3837 /* Persist any increases of mapsize config */
3838 if (mapsize < env->me_mapsize)
3839 mapsize = env->me_mapsize;
3840
3841 if (flags & MDB_WRITEMAP) {
3842 mp->mm_mapsize = mapsize;
3843 mp->mm_dbs[FREE_DBI] = txn->mt_dbs[FREE_DBI];
3844 mp->mm_dbs[MAIN_DBI] = txn->mt_dbs[MAIN_DBI];
3845 mp->mm_last_pg = txn->mt_next_pgno - 1;
3846 #if (__GNUC__ * 100 + __GNUC_MINOR__ >= 404) && /* TODO: portability */ \
3847 !(defined(__i386__) || defined(__x86_64__))
3848 /* LY: issue a memory barrier, if not x86. ITS#7969 */
3849 __sync_synchronize();
3850 #endif
3851 mp->mm_txnid = txn->mt_txnid;
3852 if (!(flags & (MDB_NOMETASYNC|MDB_NOSYNC))) {
3853 unsigned meta_size = env->me_psize;
3854 rc = (env->me_flags & MDB_MAPASYNC) ? MS_ASYNC : MS_SYNC;
3855 ptr = (char *)mp - PAGEHDRSZ;
3856 #ifndef _WIN32 /* POSIX msync() requires ptr = start of OS page */
3857 r2 = (ptr - env->me_map) & (env->me_os_psize - 1);
3858 ptr -= r2;
3859 meta_size += r2;
3860 #endif
3861 if (MDB_MSYNC(ptr, meta_size, rc)) {
3862 rc = ErrCode();
3863 goto fail;
3864 }
3865 }
3866 goto done;
3867 }
3868 metab.mm_txnid = mp->mm_txnid;
3869 metab.mm_last_pg = mp->mm_last_pg;
3870
3871 meta.mm_mapsize = mapsize;
3872 meta.mm_dbs[FREE_DBI] = txn->mt_dbs[FREE_DBI];
3873 meta.mm_dbs[MAIN_DBI] = txn->mt_dbs[MAIN_DBI];
3874 meta.mm_last_pg = txn->mt_next_pgno - 1;
3875 meta.mm_txnid = txn->mt_txnid;
3876
3877 off = offsetof(MDB_meta, mm_mapsize);
3878 ptr = (char *)&meta + off;
3879 len = sizeof(MDB_meta) - off;
3880 off += (char *)mp - env->me_map;
3881
3882 /* Write to the SYNC fd unless MDB_NOSYNC/MDB_NOMETASYNC.
3883 * (me_mfd goes to the same file as me_fd, but writing to it
3884 * also syncs to disk. Avoids a separate fdatasync() call.)
3885 */
3886 mfd = (flags & (MDB_NOSYNC|MDB_NOMETASYNC)) ? env->me_fd : env->me_mfd;
3887 #ifdef _WIN32
3888 {
3889 memset(&ov, 0, sizeof(ov));
3890 ov.Offset = off;
3891 if (!WriteFile(mfd, ptr, len, (DWORD *)&rc, &ov))
3892 rc = -1;
3893 }
3894 #else
3895 retry_write:
3896 rc = pwrite(mfd, ptr, len, off);
3897 #endif
3898 if (rc != len) {
3899 rc = rc < 0 ? ErrCode() : EIO;
3900 #ifndef _WIN32
3901 if (rc == EINTR)
3902 goto retry_write;
3903 #endif
3904 DPUTS("write failed, disk error?");
3905 /* On a failure, the pagecache still contains the new data.
3906 * Write some old data back, to prevent it from being used.
3907 * Use the non-SYNC fd; we know it will fail anyway.
3908 */
3909 meta.mm_last_pg = metab.mm_last_pg;
3910 meta.mm_txnid = metab.mm_txnid;
3911 #ifdef _WIN32
3912 memset(&ov, 0, sizeof(ov));
3913 ov.Offset = off;
3914 WriteFile(env->me_fd, ptr, len, NULL, &ov);
3915 #else
3916 r2 = pwrite(env->me_fd, ptr, len, off);
3917 (void)r2; /* Silence warnings. We don't care about pwrite's return value */
3918 #endif
3919 fail:
3920 env->me_flags |= MDB_FATAL_ERROR;
3921 return rc;
3922 }
3923 /* MIPS has cache coherency issues, this is a no-op everywhere else */
3924 CACHEFLUSH(env->me_map + off, len, DCACHE);
3925 done:
3926 /* Memory ordering issues are irrelevant; since the entire writer
3927 * is wrapped by wmutex, all of these changes will become visible
3928 * after the wmutex is unlocked. Since the DB is multi-version,
3929 * readers will get consistent data regardless of how fresh or
3930 * how stale their view of these values is.
3931 */
3932 if (env->me_txns)
3933 env->me_txns->mti_txnid = txn->mt_txnid;
3934
3935 return MDB_SUCCESS;
3936 }
3937
3938 /** Check both meta pages to see which one is newer.
3939 * @param[in] env the environment handle
3940 * @return newest #MDB_meta.
3941 */
3942 static MDB_meta *
mdb_env_pick_meta(const MDB_env * env)3943 mdb_env_pick_meta(const MDB_env *env)
3944 {
3945 MDB_meta *const *metas = env->me_metas;
3946 return metas[ metas[0]->mm_txnid < metas[1]->mm_txnid ];
3947 }
3948
3949 int ESECT
mdb_env_create(MDB_env ** env)3950 mdb_env_create(MDB_env **env)
3951 {
3952 MDB_env *e;
3953
3954 e = calloc(1, sizeof(MDB_env));
3955 if (!e)
3956 return ENOMEM;
3957
3958 e->me_maxreaders = DEFAULT_READERS;
3959 e->me_maxdbs = e->me_numdbs = CORE_DBS;
3960 e->me_fd = INVALID_HANDLE_VALUE;
3961 e->me_lfd = INVALID_HANDLE_VALUE;
3962 e->me_mfd = INVALID_HANDLE_VALUE;
3963 #ifdef MDB_USE_POSIX_SEM
3964 e->me_rmutex = SEM_FAILED;
3965 e->me_wmutex = SEM_FAILED;
3966 #endif
3967 e->me_pid = getpid();
3968 GET_PAGESIZE(e->me_os_psize);
3969 VGMEMP_CREATE(e,0,0);
3970 *env = e;
3971 return MDB_SUCCESS;
3972 }
3973
3974 static int ESECT
mdb_env_map(MDB_env * env,void * addr)3975 mdb_env_map(MDB_env *env, void *addr)
3976 {
3977 MDB_page *p;
3978 unsigned int flags = env->me_flags;
3979 #ifdef _WIN32
3980 int rc;
3981 HANDLE mh;
3982 LONG sizelo, sizehi;
3983 size_t msize;
3984
3985 if (flags & MDB_RDONLY) {
3986 /* Don't set explicit map size, use whatever exists */
3987 msize = 0;
3988 sizelo = 0;
3989 sizehi = 0;
3990 } else {
3991 msize = env->me_mapsize;
3992 sizelo = msize & 0xffffffff;
3993 sizehi = msize >> 16 >> 16; /* only needed on Win64 */
3994
3995 /* Windows won't create mappings for zero length files.
3996 * and won't map more than the file size.
3997 * Just set the maxsize right now.
3998 */
3999 if (!(flags & MDB_WRITEMAP) && (SetFilePointer(env->me_fd, sizelo, &sizehi, 0) != (DWORD)sizelo
4000 || !SetEndOfFile(env->me_fd)
4001 || SetFilePointer(env->me_fd, 0, NULL, 0) != 0))
4002 return ErrCode();
4003 }
4004
4005 mh = CreateFileMapping(env->me_fd, NULL, flags & MDB_WRITEMAP ?
4006 PAGE_READWRITE : PAGE_READONLY,
4007 sizehi, sizelo, NULL);
4008 if (!mh)
4009 return ErrCode();
4010 env->me_map = MapViewOfFileEx(mh, flags & MDB_WRITEMAP ?
4011 FILE_MAP_WRITE : FILE_MAP_READ,
4012 0, 0, msize, addr);
4013 rc = env->me_map ? 0 : ErrCode();
4014 CloseHandle(mh);
4015 if (rc)
4016 return rc;
4017 #else
4018 int mmap_flags = MAP_SHARED;
4019 int prot = PROT_READ;
4020 #ifdef MAP_NOSYNC /* Used on FreeBSD */
4021 if (flags & MDB_NOSYNC)
4022 mmap_flags |= MAP_NOSYNC;
4023 #endif
4024 if (flags & MDB_WRITEMAP) {
4025 prot |= PROT_WRITE;
4026 if (ftruncate(env->me_fd, env->me_mapsize) < 0)
4027 return ErrCode();
4028 }
4029 env->me_map = mmap(addr, env->me_mapsize, prot, mmap_flags,
4030 env->me_fd, 0);
4031 if (env->me_map == MAP_FAILED) {
4032 env->me_map = NULL;
4033 return ErrCode();
4034 }
4035
4036 if (flags & MDB_NORDAHEAD) {
4037 /* Turn off readahead. It's harmful when the DB is larger than RAM. */
4038 #ifdef MADV_RANDOM
4039 madvise(env->me_map, env->me_mapsize, MADV_RANDOM);
4040 #else
4041 #ifdef POSIX_MADV_RANDOM
4042 posix_madvise(env->me_map, env->me_mapsize, POSIX_MADV_RANDOM);
4043 #endif /* POSIX_MADV_RANDOM */
4044 #endif /* MADV_RANDOM */
4045 }
4046 #endif /* _WIN32 */
4047
4048 /* Can happen because the address argument to mmap() is just a
4049 * hint. mmap() can pick another, e.g. if the range is in use.
4050 * The MAP_FIXED flag would prevent that, but then mmap could
4051 * instead unmap existing pages to make room for the new map.
4052 */
4053 if (addr && env->me_map != addr)
4054 return EBUSY; /* TODO: Make a new MDB_* error code? */
4055
4056 p = (MDB_page *)env->me_map;
4057 env->me_metas[0] = METADATA(p);
4058 env->me_metas[1] = (MDB_meta *)((char *)env->me_metas[0] + env->me_psize);
4059
4060 return MDB_SUCCESS;
4061 }
4062
4063 int ESECT
mdb_env_set_mapsize(MDB_env * env,size_t size)4064 mdb_env_set_mapsize(MDB_env *env, size_t size)
4065 {
4066 /* If env is already open, caller is responsible for making
4067 * sure there are no active txns.
4068 */
4069 if (env->me_map) {
4070 int rc;
4071 MDB_meta *meta;
4072 void *old;
4073 if (env->me_txn)
4074 return EINVAL;
4075 meta = mdb_env_pick_meta(env);
4076 if (!size)
4077 size = meta->mm_mapsize;
4078 {
4079 /* Silently round up to minimum if the size is too small */
4080 size_t minsize = (meta->mm_last_pg + 1) * env->me_psize;
4081 if (size < minsize)
4082 size = minsize;
4083 }
4084 munmap(env->me_map, env->me_mapsize);
4085 env->me_mapsize = size;
4086 old = (env->me_flags & MDB_FIXEDMAP) ? env->me_map : NULL;
4087 rc = mdb_env_map(env, old);
4088 if (rc)
4089 return rc;
4090 }
4091 env->me_mapsize = size;
4092 if (env->me_psize)
4093 env->me_maxpg = env->me_mapsize / env->me_psize;
4094 return MDB_SUCCESS;
4095 }
4096
4097 int ESECT
mdb_env_set_maxdbs(MDB_env * env,MDB_dbi dbs)4098 mdb_env_set_maxdbs(MDB_env *env, MDB_dbi dbs)
4099 {
4100 if (env->me_map)
4101 return EINVAL;
4102 env->me_maxdbs = dbs + CORE_DBS;
4103 return MDB_SUCCESS;
4104 }
4105
4106 int ESECT
mdb_env_set_maxreaders(MDB_env * env,unsigned int readers)4107 mdb_env_set_maxreaders(MDB_env *env, unsigned int readers)
4108 {
4109 if (env->me_map || readers < 1)
4110 return EINVAL;
4111 env->me_maxreaders = readers;
4112 return MDB_SUCCESS;
4113 }
4114
4115 int ESECT
mdb_env_get_maxreaders(MDB_env * env,unsigned int * readers)4116 mdb_env_get_maxreaders(MDB_env *env, unsigned int *readers)
4117 {
4118 if (!env || !readers)
4119 return EINVAL;
4120 *readers = env->me_maxreaders;
4121 return MDB_SUCCESS;
4122 }
4123
4124 static int ESECT
mdb_fsize(HANDLE fd,size_t * size)4125 mdb_fsize(HANDLE fd, size_t *size)
4126 {
4127 #ifdef _WIN32
4128 LARGE_INTEGER fsize;
4129
4130 if (!GetFileSizeEx(fd, &fsize))
4131 return ErrCode();
4132
4133 *size = fsize.QuadPart;
4134 #else
4135 struct stat st;
4136
4137 if (fstat(fd, &st))
4138 return ErrCode();
4139
4140 *size = st.st_size;
4141 #endif
4142 return MDB_SUCCESS;
4143 }
4144
4145
4146 #ifdef _WIN32
4147 typedef wchar_t mdb_nchar_t;
4148 # define MDB_NAME(str) L##str
4149 # define mdb_name_cpy wcscpy
4150 #else
4151 /** Character type for file names: char on Unix, wchar_t on Windows */
4152 typedef char mdb_nchar_t;
4153 # define MDB_NAME(str) str /**< #mdb_nchar_t[] string literal */
4154 # define mdb_name_cpy strcpy /**< Copy name (#mdb_nchar_t string) */
4155 #endif
4156
4157 /** Filename - string of #mdb_nchar_t[] */
4158 typedef struct MDB_name {
4159 int mn_len; /**< Length */
4160 int mn_alloced; /**< True if #mn_val was malloced */
4161 mdb_nchar_t *mn_val; /**< Contents */
4162 } MDB_name;
4163
4164 /** Filename suffixes [datafile,lockfile][without,with MDB_NOSUBDIR] */
4165 static const mdb_nchar_t *const mdb_suffixes[2][2] = {
4166 { MDB_NAME("/data.mdb"), MDB_NAME("") },
4167 { MDB_NAME("/lock.mdb"), MDB_NAME("-lock") }
4168 };
4169
4170 #define MDB_SUFFLEN 9 /**< Max string length in #mdb_suffixes[] */
4171
4172 /** Set up filename + scratch area for filename suffix, for opening files.
4173 * It should be freed with #mdb_fname_destroy().
4174 * On Windows, paths are converted from char *UTF-8 to wchar_t *UTF-16.
4175 *
4176 * @param[in] path Pathname for #mdb_env_open().
4177 * @param[in] envflags Whether a subdir and/or lockfile will be used.
4178 * @param[out] fname Resulting filename, with room for a suffix if necessary.
4179 */
4180 static int ESECT
mdb_fname_init(const char * path,unsigned envflags,MDB_name * fname)4181 mdb_fname_init(const char *path, unsigned envflags, MDB_name *fname)
4182 {
4183 int no_suffix = F_ISSET(envflags, MDB_NOSUBDIR|MDB_NOLOCK);
4184 fname->mn_alloced = 0;
4185 #ifdef _WIN32
4186 return utf8_to_utf16(path, fname, no_suffix ? 0 : MDB_SUFFLEN);
4187 #else
4188 fname->mn_len = strlen(path);
4189 if (no_suffix)
4190 fname->mn_val = (char *) path;
4191 else if ((fname->mn_val = malloc(fname->mn_len + MDB_SUFFLEN+1)) != NULL) {
4192 fname->mn_alloced = 1;
4193 strcpy(fname->mn_val, path);
4194 }
4195 else
4196 return ENOMEM;
4197 return MDB_SUCCESS;
4198 #endif
4199 }
4200
4201 /** Destroy \b fname from #mdb_fname_init() */
4202 #define mdb_fname_destroy(fname) \
4203 do { if ((fname).mn_alloced) free((fname).mn_val); } while (0)
4204
4205 #ifdef O_CLOEXEC /* POSIX.1-2008: Set FD_CLOEXEC atomically at open() */
4206 # define MDB_CLOEXEC O_CLOEXEC
4207 #else
4208 # define MDB_CLOEXEC 0
4209 #endif
4210
4211 /** File type, access mode etc. for #mdb_fopen() */
4212 enum mdb_fopen_type {
4213 #ifdef _WIN32
4214 MDB_O_RDONLY, MDB_O_RDWR, MDB_O_META, MDB_O_COPY, MDB_O_LOCKS
4215 #else
4216 /* A comment in mdb_fopen() explains some O_* flag choices. */
4217 MDB_O_RDONLY= O_RDONLY, /**< for RDONLY me_fd */
4218 MDB_O_RDWR = O_RDWR |O_CREAT, /**< for me_fd */
4219 MDB_O_META = O_WRONLY|MDB_DSYNC |MDB_CLOEXEC, /**< for me_mfd */
4220 MDB_O_COPY = O_WRONLY|O_CREAT|O_EXCL|MDB_CLOEXEC, /**< for #mdb_env_copy() */
4221 /** Bitmask for open() flags in enum #mdb_fopen_type. The other bits
4222 * distinguish otherwise-equal MDB_O_* constants from each other.
4223 */
4224 MDB_O_MASK = MDB_O_RDWR|MDB_CLOEXEC | MDB_O_RDONLY|MDB_O_META|MDB_O_COPY,
4225 MDB_O_LOCKS = MDB_O_RDWR|MDB_CLOEXEC | ((MDB_O_MASK+1) & ~MDB_O_MASK) /**< for me_lfd */
4226 #endif
4227 };
4228
4229 /** Open an LMDB file.
4230 * @param[in] env The LMDB environment.
4231 * @param[in,out] fname Path from from #mdb_fname_init(). A suffix is
4232 * appended if necessary to create the filename, without changing mn_len.
4233 * @param[in] which Determines file type, access mode, etc.
4234 * @param[in] mode The Unix permissions for the file, if we create it.
4235 * @param[out] res Resulting file handle.
4236 * @return 0 on success, non-zero on failure.
4237 */
4238 static int ESECT
mdb_fopen(const MDB_env * env,MDB_name * fname,enum mdb_fopen_type which,mdb_mode_t mode,HANDLE * res)4239 mdb_fopen(const MDB_env *env, MDB_name *fname,
4240 enum mdb_fopen_type which, mdb_mode_t mode,
4241 HANDLE *res)
4242 {
4243 int rc = MDB_SUCCESS;
4244 HANDLE fd;
4245 #ifdef _WIN32
4246 DWORD acc, share, disp, attrs;
4247 #else
4248 int flags;
4249 #endif
4250
4251 if (fname->mn_alloced) /* modifiable copy */
4252 mdb_name_cpy(fname->mn_val + fname->mn_len,
4253 mdb_suffixes[which==MDB_O_LOCKS][F_ISSET(env->me_flags, MDB_NOSUBDIR)]);
4254
4255 /* The directory must already exist. Usually the file need not.
4256 * MDB_O_META requires the file because we already created it using
4257 * MDB_O_RDWR. MDB_O_COPY must not overwrite an existing file.
4258 *
4259 * With MDB_O_COPY we do not want the OS to cache the writes, since
4260 * the source data is already in the OS cache.
4261 *
4262 * The lockfile needs FD_CLOEXEC (close file descriptor on exec*())
4263 * to avoid the flock() issues noted under Caveats in lmdb.h.
4264 * Also set it for other filehandles which the user cannot get at
4265 * and close himself, which he may need after fork(). I.e. all but
4266 * me_fd, which programs do use via mdb_env_get_fd().
4267 */
4268
4269 #ifdef _WIN32
4270 acc = GENERIC_READ|GENERIC_WRITE;
4271 share = FILE_SHARE_READ|FILE_SHARE_WRITE;
4272 disp = OPEN_ALWAYS;
4273 attrs = FILE_ATTRIBUTE_NORMAL;
4274 switch (which) {
4275 case MDB_O_RDONLY: /* read-only datafile */
4276 acc = GENERIC_READ;
4277 disp = OPEN_EXISTING;
4278 break;
4279 case MDB_O_META: /* for writing metapages */
4280 acc = GENERIC_WRITE;
4281 disp = OPEN_EXISTING;
4282 attrs = FILE_ATTRIBUTE_NORMAL|FILE_FLAG_WRITE_THROUGH;
4283 break;
4284 case MDB_O_COPY: /* mdb_env_copy() & co */
4285 acc = GENERIC_WRITE;
4286 share = 0;
4287 disp = CREATE_NEW;
4288 attrs = FILE_FLAG_NO_BUFFERING|FILE_FLAG_WRITE_THROUGH;
4289 break;
4290 default: break; /* silence gcc -Wswitch (not all enum values handled) */
4291 }
4292 fd = CreateFileW(fname->mn_val, acc, share, NULL, disp, attrs, NULL);
4293 #else
4294 fd = open(fname->mn_val, which & MDB_O_MASK, mode);
4295 #endif
4296
4297 if (fd == INVALID_HANDLE_VALUE)
4298 rc = ErrCode();
4299 #ifndef _WIN32
4300 else {
4301 if (which != MDB_O_RDONLY && which != MDB_O_RDWR) {
4302 /* Set CLOEXEC if we could not pass it to open() */
4303 if (!MDB_CLOEXEC && (flags = fcntl(fd, F_GETFD)) != -1)
4304 (void) fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
4305 }
4306 if (which == MDB_O_COPY && env->me_psize >= env->me_os_psize) {
4307 /* This may require buffer alignment. There is no portable
4308 * way to ask how much, so we require OS pagesize alignment.
4309 */
4310 # ifdef F_NOCACHE /* __APPLE__ */
4311 (void) fcntl(fd, F_NOCACHE, 1);
4312 # elif defined O_DIRECT
4313 /* open(...O_DIRECT...) would break on filesystems without
4314 * O_DIRECT support (ITS#7682). Try to set it here instead.
4315 */
4316 if ((flags = fcntl(fd, F_GETFL)) != -1)
4317 (void) fcntl(fd, F_SETFL, flags | O_DIRECT);
4318 # endif
4319 }
4320 }
4321 #endif /* !_WIN32 */
4322
4323 *res = fd;
4324 return rc;
4325 }
4326
4327
4328 #ifdef BROKEN_FDATASYNC
4329 #include <sys/utsname.h>
4330 #include <sys/vfs.h>
4331 #endif
4332
4333 /** Further setup required for opening an LMDB environment
4334 */
4335 static int ESECT
mdb_env_open2(MDB_env * env)4336 mdb_env_open2(MDB_env *env)
4337 {
4338 unsigned int flags = env->me_flags;
4339 int i, newenv = 0, rc;
4340 MDB_meta meta;
4341
4342 #ifdef _WIN32
4343 /* See if we should use QueryLimited */
4344 rc = GetVersion();
4345 if ((rc & 0xff) > 5)
4346 env->me_pidquery = MDB_PROCESS_QUERY_LIMITED_INFORMATION;
4347 else
4348 env->me_pidquery = PROCESS_QUERY_INFORMATION;
4349 #endif /* _WIN32 */
4350
4351 #ifdef BROKEN_FDATASYNC
4352 /* ext3/ext4 fdatasync is broken on some older Linux kernels.
4353 * https://lkml.org/lkml/2012/9/3/83
4354 * Kernels after 3.6-rc6 are known good.
4355 * https://lkml.org/lkml/2012/9/10/556
4356 * See if the DB is on ext3/ext4, then check for new enough kernel
4357 * Kernels 2.6.32.60, 2.6.34.15, 3.2.30, and 3.5.4 are also known
4358 * to be patched.
4359 */
4360 {
4361 struct statfs st;
4362 fstatfs(env->me_fd, &st);
4363 while (st.f_type == 0xEF53) {
4364 struct utsname uts;
4365 int i;
4366 uname(&uts);
4367 if (uts.release[0] < '3') {
4368 if (!strncmp(uts.release, "2.6.32.", 7)) {
4369 i = atoi(uts.release+7);
4370 if (i >= 60)
4371 break; /* 2.6.32.60 and newer is OK */
4372 } else if (!strncmp(uts.release, "2.6.34.", 7)) {
4373 i = atoi(uts.release+7);
4374 if (i >= 15)
4375 break; /* 2.6.34.15 and newer is OK */
4376 }
4377 } else if (uts.release[0] == '3') {
4378 i = atoi(uts.release+2);
4379 if (i > 5)
4380 break; /* 3.6 and newer is OK */
4381 if (i == 5) {
4382 i = atoi(uts.release+4);
4383 if (i >= 4)
4384 break; /* 3.5.4 and newer is OK */
4385 } else if (i == 2) {
4386 i = atoi(uts.release+4);
4387 if (i >= 30)
4388 break; /* 3.2.30 and newer is OK */
4389 }
4390 } else { /* 4.x and newer is OK */
4391 break;
4392 }
4393 env->me_flags |= MDB_FSYNCONLY;
4394 break;
4395 }
4396 }
4397 #endif
4398
4399 if ((i = mdb_env_read_header(env, &meta)) != 0) {
4400 if (i != ENOENT)
4401 return i;
4402 DPUTS("new mdbenv");
4403 newenv = 1;
4404 env->me_psize = env->me_os_psize;
4405 if (env->me_psize > MAX_PAGESIZE)
4406 env->me_psize = MAX_PAGESIZE;
4407 memset(&meta, 0, sizeof(meta));
4408 mdb_env_init_meta0(env, &meta);
4409 meta.mm_mapsize = DEFAULT_MAPSIZE;
4410 } else {
4411 env->me_psize = meta.mm_psize;
4412 }
4413
4414 /* Was a mapsize configured? */
4415 if (!env->me_mapsize) {
4416 env->me_mapsize = meta.mm_mapsize;
4417 }
4418 {
4419 /* Make sure mapsize >= committed data size. Even when using
4420 * mm_mapsize, which could be broken in old files (ITS#7789).
4421 */
4422 size_t minsize = (meta.mm_last_pg + 1) * meta.mm_psize;
4423 if (env->me_mapsize < minsize)
4424 env->me_mapsize = minsize;
4425 }
4426 meta.mm_mapsize = env->me_mapsize;
4427
4428 if (newenv && !(flags & MDB_FIXEDMAP)) {
4429 /* mdb_env_map() may grow the datafile. Write the metapages
4430 * first, so the file will be valid if initialization fails.
4431 * Except with FIXEDMAP, since we do not yet know mm_address.
4432 * We could fill in mm_address later, but then a different
4433 * program might end up doing that - one with a memory layout
4434 * and map address which does not suit the main program.
4435 */
4436 rc = mdb_env_init_meta(env, &meta);
4437 if (rc)
4438 return rc;
4439 newenv = 0;
4440 }
4441
4442 rc = mdb_env_map(env, (flags & MDB_FIXEDMAP) ? meta.mm_address : NULL);
4443 if (rc)
4444 return rc;
4445
4446 if (newenv) {
4447 if (flags & MDB_FIXEDMAP)
4448 meta.mm_address = env->me_map;
4449 i = mdb_env_init_meta(env, &meta);
4450 if (i != MDB_SUCCESS) {
4451 return i;
4452 }
4453 }
4454
4455 env->me_maxfree_1pg = (env->me_psize - PAGEHDRSZ) / sizeof(pgno_t) - 1;
4456 env->me_nodemax = (((env->me_psize - PAGEHDRSZ) / MDB_MINKEYS) & -2)
4457 - sizeof(indx_t);
4458 #if !(MDB_MAXKEYSIZE)
4459 env->me_maxkey = env->me_nodemax - (NODESIZE + sizeof(MDB_db));
4460 #endif
4461 env->me_maxpg = env->me_mapsize / env->me_psize;
4462
4463 #if MDB_DEBUG
4464 {
4465 MDB_meta *meta = mdb_env_pick_meta(env);
4466 MDB_db *db = &meta->mm_dbs[MAIN_DBI];
4467
4468 DPRINTF(("opened database version %u, pagesize %u",
4469 meta->mm_version, env->me_psize));
4470 DPRINTF(("using meta page %d", (int) (meta->mm_txnid & 1)));
4471 DPRINTF(("depth: %u", db->md_depth));
4472 DPRINTF(("entries: %"Z"u", db->md_entries));
4473 DPRINTF(("branch pages: %"Z"u", db->md_branch_pages));
4474 DPRINTF(("leaf pages: %"Z"u", db->md_leaf_pages));
4475 DPRINTF(("overflow pages: %"Z"u", db->md_overflow_pages));
4476 DPRINTF(("root: %"Z"u", db->md_root));
4477 }
4478 #endif
4479
4480 return MDB_SUCCESS;
4481 }
4482
4483
4484 /** Release a reader thread's slot in the reader lock table.
4485 * This function is called automatically when a thread exits.
4486 * @param[in] ptr This points to the slot in the reader lock table.
4487 */
4488 static void
mdb_env_reader_dest(void * ptr)4489 mdb_env_reader_dest(void *ptr)
4490 {
4491 MDB_reader *reader = ptr;
4492
4493 #ifndef _WIN32
4494 if (reader->mr_pid == getpid()) /* catch pthread_exit() in child process */
4495 #endif
4496 /* We omit the mutex, so do this atomically (i.e. skip mr_txnid) */
4497 reader->mr_pid = 0;
4498 }
4499
4500 #ifdef _WIN32
4501 /** Junk for arranging thread-specific callbacks on Windows. This is
4502 * necessarily platform and compiler-specific. Windows supports up
4503 * to 1088 keys. Let's assume nobody opens more than 64 environments
4504 * in a single process, for now. They can override this if needed.
4505 */
4506 #ifndef MAX_TLS_KEYS
4507 #define MAX_TLS_KEYS 64
4508 #endif
4509 static pthread_key_t mdb_tls_keys[MAX_TLS_KEYS];
4510 static int mdb_tls_nkeys;
4511
mdb_tls_callback(PVOID module,DWORD reason,PVOID ptr)4512 static void NTAPI mdb_tls_callback(PVOID module, DWORD reason, PVOID ptr)
4513 {
4514 int i;
4515 switch(reason) {
4516 case DLL_PROCESS_ATTACH: break;
4517 case DLL_THREAD_ATTACH: break;
4518 case DLL_THREAD_DETACH:
4519 for (i=0; i<mdb_tls_nkeys; i++) {
4520 MDB_reader *r = pthread_getspecific(mdb_tls_keys[i]);
4521 if (r) {
4522 mdb_env_reader_dest(r);
4523 }
4524 }
4525 break;
4526 case DLL_PROCESS_DETACH: break;
4527 }
4528 }
4529 #ifdef __GNUC__
4530 #ifdef _WIN64
4531 const PIMAGE_TLS_CALLBACK mdb_tls_cbp __attribute__((section (".CRT$XLB"))) = mdb_tls_callback;
4532 #else
4533 PIMAGE_TLS_CALLBACK mdb_tls_cbp __attribute__((section (".CRT$XLB"))) = mdb_tls_callback;
4534 #endif
4535 #else
4536 #ifdef _WIN64
4537 /* Force some symbol references.
4538 * _tls_used forces the linker to create the TLS directory if not already done
4539 * mdb_tls_cbp prevents whole-program-optimizer from dropping the symbol.
4540 */
4541 #pragma comment(linker, "/INCLUDE:_tls_used")
4542 #pragma comment(linker, "/INCLUDE:mdb_tls_cbp")
4543 #pragma const_seg(".CRT$XLB")
4544 extern const PIMAGE_TLS_CALLBACK mdb_tls_cbp;
4545 const PIMAGE_TLS_CALLBACK mdb_tls_cbp = mdb_tls_callback;
4546 #pragma const_seg()
4547 #else /* _WIN32 */
4548 #pragma comment(linker, "/INCLUDE:__tls_used")
4549 #pragma comment(linker, "/INCLUDE:_mdb_tls_cbp")
4550 #pragma data_seg(".CRT$XLB")
4551 PIMAGE_TLS_CALLBACK mdb_tls_cbp = mdb_tls_callback;
4552 #pragma data_seg()
4553 #endif /* WIN 32/64 */
4554 #endif /* !__GNUC__ */
4555 #endif
4556
4557 /** Downgrade the exclusive lock on the region back to shared */
4558 static int ESECT
mdb_env_share_locks(MDB_env * env,int * excl)4559 mdb_env_share_locks(MDB_env *env, int *excl)
4560 {
4561 int rc = 0;
4562 MDB_meta *meta = mdb_env_pick_meta(env);
4563
4564 env->me_txns->mti_txnid = meta->mm_txnid;
4565
4566 #ifdef _WIN32
4567 {
4568 OVERLAPPED ov;
4569 /* First acquire a shared lock. The Unlock will
4570 * then release the existing exclusive lock.
4571 */
4572 memset(&ov, 0, sizeof(ov));
4573 if (!LockFileEx(env->me_lfd, 0, 0, 1, 0, &ov)) {
4574 rc = ErrCode();
4575 } else {
4576 UnlockFile(env->me_lfd, 0, 0, 1, 0);
4577 *excl = 0;
4578 }
4579 }
4580 #else
4581 {
4582 struct flock lock_info;
4583 /* The shared lock replaces the existing lock */
4584 memset((void *)&lock_info, 0, sizeof(lock_info));
4585 lock_info.l_type = F_RDLCK;
4586 lock_info.l_whence = SEEK_SET;
4587 lock_info.l_start = 0;
4588 lock_info.l_len = 1;
4589 while ((rc = fcntl(env->me_lfd, F_SETLK, &lock_info)) &&
4590 (rc = ErrCode()) == EINTR) ;
4591 *excl = rc ? -1 : 0; /* error may mean we lost the lock */
4592 }
4593 #endif
4594
4595 return rc;
4596 }
4597
4598 /** Try to get exclusive lock, otherwise shared.
4599 * Maintain *excl = -1: no/unknown lock, 0: shared, 1: exclusive.
4600 */
4601 static int ESECT
mdb_env_excl_lock(MDB_env * env,int * excl)4602 mdb_env_excl_lock(MDB_env *env, int *excl)
4603 {
4604 int rc = 0;
4605 #ifdef _WIN32
4606 if (LockFile(env->me_lfd, 0, 0, 1, 0)) {
4607 *excl = 1;
4608 } else {
4609 OVERLAPPED ov;
4610 memset(&ov, 0, sizeof(ov));
4611 if (LockFileEx(env->me_lfd, 0, 0, 1, 0, &ov)) {
4612 *excl = 0;
4613 } else {
4614 rc = ErrCode();
4615 }
4616 }
4617 #else
4618 struct flock lock_info;
4619 memset((void *)&lock_info, 0, sizeof(lock_info));
4620 lock_info.l_type = F_WRLCK;
4621 lock_info.l_whence = SEEK_SET;
4622 lock_info.l_start = 0;
4623 lock_info.l_len = 1;
4624 while ((rc = fcntl(env->me_lfd, F_SETLK, &lock_info)) &&
4625 (rc = ErrCode()) == EINTR) ;
4626 if (!rc) {
4627 *excl = 1;
4628 } else
4629 # ifndef MDB_USE_POSIX_MUTEX
4630 if (*excl < 0) /* always true when MDB_USE_POSIX_MUTEX */
4631 # endif
4632 {
4633 lock_info.l_type = F_RDLCK;
4634 while ((rc = fcntl(env->me_lfd, F_SETLKW, &lock_info)) &&
4635 (rc = ErrCode()) == EINTR) ;
4636 if (rc == 0)
4637 *excl = 0;
4638 }
4639 #endif
4640 return rc;
4641 }
4642
4643 #ifdef MDB_USE_HASH
4644 /*
4645 * hash_64 - 64 bit Fowler/Noll/Vo-0 FNV-1a hash code
4646 *
4647 * @(#) Revision: 5.1
4648 * @(#) Id: hash_64a.c,v 5.1 2009/06/30 09:01:38 chongo Exp
4649 * @(#) Source: /usr/local/src/cmd/fnv/RCS/hash_64a.c,v
4650 *
4651 * http://www.isthe.com/chongo/tech/comp/fnv/index.html
4652 *
4653 ***
4654 *
4655 * Please do not copyright this code. This code is in the public domain.
4656 *
4657 * LANDON CURT NOLL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
4658 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO
4659 * EVENT SHALL LANDON CURT NOLL BE LIABLE FOR ANY SPECIAL, INDIRECT OR
4660 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
4661 * USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
4662 * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
4663 * PERFORMANCE OF THIS SOFTWARE.
4664 *
4665 * By:
4666 * chongo <Landon Curt Noll> /\oo/\
4667 * http://www.isthe.com/chongo/
4668 *
4669 * Share and Enjoy! :-)
4670 */
4671
4672 typedef unsigned long long mdb_hash_t;
4673 #define MDB_HASH_INIT ((mdb_hash_t)0xcbf29ce484222325ULL)
4674
4675 /** perform a 64 bit Fowler/Noll/Vo FNV-1a hash on a buffer
4676 * @param[in] val value to hash
4677 * @param[in] hval initial value for hash
4678 * @return 64 bit hash
4679 *
4680 * NOTE: To use the recommended 64 bit FNV-1a hash, use MDB_HASH_INIT as the
4681 * hval arg on the first call.
4682 */
4683 static mdb_hash_t
mdb_hash_val(MDB_val * val,mdb_hash_t hval)4684 mdb_hash_val(MDB_val *val, mdb_hash_t hval)
4685 {
4686 unsigned char *s = (unsigned char *)val->mv_data; /* unsigned string */
4687 unsigned char *end = s + val->mv_size;
4688 /*
4689 * FNV-1a hash each octet of the string
4690 */
4691 while (s < end) {
4692 /* xor the bottom with the current octet */
4693 hval ^= (mdb_hash_t)*s++;
4694
4695 /* multiply by the 64 bit FNV magic prime mod 2^64 */
4696 hval += (hval << 1) + (hval << 4) + (hval << 5) +
4697 (hval << 7) + (hval << 8) + (hval << 40);
4698 }
4699 /* return our new hash value */
4700 return hval;
4701 }
4702
4703 /** Hash the string and output the encoded hash.
4704 * This uses modified RFC1924 Ascii85 encoding to accommodate systems with
4705 * very short name limits. We don't care about the encoding being reversible,
4706 * we just want to preserve as many bits of the input as possible in a
4707 * small printable string.
4708 * @param[in] str string to hash
4709 * @param[out] encbuf an array of 11 chars to hold the hash
4710 */
4711 static const char mdb_a85[]= "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz!#$%&()*+-;<=>?@^_`{|}~";
4712
4713 static void ESECT
mdb_pack85(unsigned long l,char * out)4714 mdb_pack85(unsigned long l, char *out)
4715 {
4716 int i;
4717
4718 for (i=0; i<5; i++) {
4719 *out++ = mdb_a85[l % 85];
4720 l /= 85;
4721 }
4722 }
4723
4724 static void ESECT
mdb_hash_enc(MDB_val * val,char * encbuf)4725 mdb_hash_enc(MDB_val *val, char *encbuf)
4726 {
4727 mdb_hash_t h = mdb_hash_val(val, MDB_HASH_INIT);
4728
4729 mdb_pack85(h, encbuf);
4730 mdb_pack85(h>>32, encbuf+5);
4731 encbuf[10] = '\0';
4732 }
4733 #endif
4734
4735 /** Open and/or initialize the lock region for the environment.
4736 * @param[in] env The LMDB environment.
4737 * @param[in] fname Filename + scratch area, from #mdb_fname_init().
4738 * @param[in] mode The Unix permissions for the file, if we create it.
4739 * @param[in,out] excl In -1, out lock type: -1 none, 0 shared, 1 exclusive
4740 * @return 0 on success, non-zero on failure.
4741 */
4742 static int ESECT
mdb_env_setup_locks(MDB_env * env,MDB_name * fname,int mode,int * excl)4743 mdb_env_setup_locks(MDB_env *env, MDB_name *fname, int mode, int *excl)
4744 {
4745 #ifdef _WIN32
4746 # define MDB_ERRCODE_ROFS ERROR_WRITE_PROTECT
4747 #else
4748 # define MDB_ERRCODE_ROFS EROFS
4749 #endif
4750 int rc;
4751 off_t size, rsize;
4752
4753 rc = mdb_fopen(env, fname, MDB_O_LOCKS, mode, &env->me_lfd);
4754 if (rc) {
4755 /* Omit lockfile if read-only env on read-only filesystem */
4756 if (rc == MDB_ERRCODE_ROFS && (env->me_flags & MDB_RDONLY)) {
4757 return MDB_SUCCESS;
4758 }
4759 goto fail;
4760 }
4761
4762 if (!(env->me_flags & MDB_NOTLS)) {
4763 rc = pthread_key_create(&env->me_txkey, mdb_env_reader_dest);
4764 if (rc)
4765 goto fail;
4766 env->me_flags |= MDB_ENV_TXKEY;
4767 #ifdef _WIN32
4768 /* Windows TLS callbacks need help finding their TLS info. */
4769 if (mdb_tls_nkeys >= MAX_TLS_KEYS) {
4770 rc = MDB_TLS_FULL;
4771 goto fail;
4772 }
4773 mdb_tls_keys[mdb_tls_nkeys++] = env->me_txkey;
4774 #endif
4775 }
4776
4777 /* Try to get exclusive lock. If we succeed, then
4778 * nobody is using the lock region and we should initialize it.
4779 */
4780 if ((rc = mdb_env_excl_lock(env, excl))) goto fail;
4781
4782 #ifdef _WIN32
4783 size = GetFileSize(env->me_lfd, NULL);
4784 #else
4785 size = lseek(env->me_lfd, 0, SEEK_END);
4786 if (size == -1) goto fail_errno;
4787 #endif
4788 rsize = (env->me_maxreaders-1) * sizeof(MDB_reader) + sizeof(MDB_txninfo);
4789 if (size < rsize && *excl > 0) {
4790 #ifdef _WIN32
4791 if (SetFilePointer(env->me_lfd, rsize, NULL, FILE_BEGIN) != (DWORD)rsize
4792 || !SetEndOfFile(env->me_lfd))
4793 goto fail_errno;
4794 #else
4795 if (ftruncate(env->me_lfd, rsize) != 0) goto fail_errno;
4796 #endif
4797 } else {
4798 rsize = size;
4799 size = rsize - sizeof(MDB_txninfo);
4800 env->me_maxreaders = size/sizeof(MDB_reader) + 1;
4801 }
4802 {
4803 #ifdef _WIN32
4804 HANDLE mh;
4805 mh = CreateFileMapping(env->me_lfd, NULL, PAGE_READWRITE,
4806 0, 0, NULL);
4807 if (!mh) goto fail_errno;
4808 env->me_txns = MapViewOfFileEx(mh, FILE_MAP_WRITE, 0, 0, rsize, NULL);
4809 CloseHandle(mh);
4810 if (!env->me_txns) goto fail_errno;
4811 #else
4812 void *m = mmap(NULL, rsize, PROT_READ|PROT_WRITE, MAP_SHARED,
4813 env->me_lfd, 0);
4814 if (m == MAP_FAILED) goto fail_errno;
4815 env->me_txns = m;
4816 #endif
4817 }
4818 if (*excl > 0) {
4819 #ifdef _WIN32
4820 BY_HANDLE_FILE_INFORMATION stbuf;
4821 struct {
4822 DWORD volume;
4823 DWORD nhigh;
4824 DWORD nlow;
4825 } idbuf;
4826 MDB_val val;
4827 char encbuf[11];
4828
4829 if (!mdb_sec_inited) {
4830 InitializeSecurityDescriptor(&mdb_null_sd,
4831 SECURITY_DESCRIPTOR_REVISION);
4832 SetSecurityDescriptorDacl(&mdb_null_sd, TRUE, 0, FALSE);
4833 mdb_all_sa.nLength = sizeof(SECURITY_ATTRIBUTES);
4834 mdb_all_sa.bInheritHandle = FALSE;
4835 mdb_all_sa.lpSecurityDescriptor = &mdb_null_sd;
4836 mdb_sec_inited = 1;
4837 }
4838 if (!GetFileInformationByHandle(env->me_lfd, &stbuf)) goto fail_errno;
4839 idbuf.volume = stbuf.dwVolumeSerialNumber;
4840 idbuf.nhigh = stbuf.nFileIndexHigh;
4841 idbuf.nlow = stbuf.nFileIndexLow;
4842 val.mv_data = &idbuf;
4843 val.mv_size = sizeof(idbuf);
4844 mdb_hash_enc(&val, encbuf);
4845 sprintf(env->me_txns->mti_rmname, "Global\\MDBr%s", encbuf);
4846 sprintf(env->me_txns->mti_wmname, "Global\\MDBw%s", encbuf);
4847 env->me_rmutex = CreateMutexA(&mdb_all_sa, FALSE, env->me_txns->mti_rmname);
4848 if (!env->me_rmutex) goto fail_errno;
4849 env->me_wmutex = CreateMutexA(&mdb_all_sa, FALSE, env->me_txns->mti_wmname);
4850 if (!env->me_wmutex) goto fail_errno;
4851 #elif defined(MDB_USE_POSIX_SEM)
4852 struct stat stbuf;
4853 struct {
4854 dev_t dev;
4855 ino_t ino;
4856 } idbuf;
4857 MDB_val val;
4858 char encbuf[11];
4859
4860 #if defined(__NetBSD__)
4861 #define MDB_SHORT_SEMNAMES 1 /* limited to 14 chars */
4862 #endif
4863 if (fstat(env->me_lfd, &stbuf)) goto fail_errno;
4864 idbuf.dev = stbuf.st_dev;
4865 idbuf.ino = stbuf.st_ino;
4866 val.mv_data = &idbuf;
4867 val.mv_size = sizeof(idbuf);
4868 mdb_hash_enc(&val, encbuf);
4869 #ifdef MDB_SHORT_SEMNAMES
4870 encbuf[9] = '\0'; /* drop name from 15 chars to 14 chars */
4871 #endif
4872 sprintf(env->me_txns->mti_rmname, "/MDBr%s", encbuf);
4873 sprintf(env->me_txns->mti_wmname, "/MDBw%s", encbuf);
4874 /* Clean up after a previous run, if needed: Try to
4875 * remove both semaphores before doing anything else.
4876 */
4877 sem_unlink(env->me_txns->mti_rmname);
4878 sem_unlink(env->me_txns->mti_wmname);
4879 env->me_rmutex = sem_open(env->me_txns->mti_rmname,
4880 O_CREAT|O_EXCL, mode, 1);
4881 if (env->me_rmutex == SEM_FAILED) goto fail_errno;
4882 env->me_wmutex = sem_open(env->me_txns->mti_wmname,
4883 O_CREAT|O_EXCL, mode, 1);
4884 if (env->me_wmutex == SEM_FAILED) goto fail_errno;
4885 #else /* MDB_USE_POSIX_MUTEX: */
4886 pthread_mutexattr_t mattr;
4887
4888 /* Solaris needs this before initing a robust mutex. Otherwise
4889 * it may skip the init and return EBUSY "seems someone already
4890 * inited" or EINVAL "it was inited differently".
4891 */
4892 memset(env->me_txns->mti_rmutex, 0, sizeof(*env->me_txns->mti_rmutex));
4893 memset(env->me_txns->mti_wmutex, 0, sizeof(*env->me_txns->mti_wmutex));
4894
4895 if ((rc = pthread_mutexattr_init(&mattr)))
4896 goto fail;
4897
4898 rc = pthread_mutexattr_setpshared(&mattr, PTHREAD_PROCESS_SHARED);
4899 #ifdef MDB_ROBUST_SUPPORTED
4900 if (!rc) rc = pthread_mutexattr_setrobust(&mattr, PTHREAD_MUTEX_ROBUST);
4901 #endif
4902 if (!rc) rc = pthread_mutex_init(env->me_txns->mti_rmutex, &mattr);
4903 if (!rc) rc = pthread_mutex_init(env->me_txns->mti_wmutex, &mattr);
4904 pthread_mutexattr_destroy(&mattr);
4905 if (rc)
4906 goto fail;
4907 #endif /* _WIN32 || MDB_USE_POSIX_SEM */
4908
4909 env->me_txns->mti_magic = MDB_MAGIC;
4910 env->me_txns->mti_format = MDB_LOCK_FORMAT;
4911 env->me_txns->mti_txnid = 0;
4912 env->me_txns->mti_numreaders = 0;
4913
4914 } else {
4915 if (env->me_txns->mti_magic != MDB_MAGIC) {
4916 DPUTS("lock region has invalid magic");
4917 rc = MDB_INVALID;
4918 goto fail;
4919 }
4920 if (env->me_txns->mti_format != MDB_LOCK_FORMAT) {
4921 DPRINTF(("lock region has format+version 0x%x, expected 0x%x",
4922 env->me_txns->mti_format, MDB_LOCK_FORMAT));
4923 rc = MDB_VERSION_MISMATCH;
4924 goto fail;
4925 }
4926 rc = ErrCode();
4927 if (rc && rc != EACCES && rc != EAGAIN) {
4928 goto fail;
4929 }
4930 #ifdef _WIN32
4931 env->me_rmutex = OpenMutexA(SYNCHRONIZE, FALSE, env->me_txns->mti_rmname);
4932 if (!env->me_rmutex) goto fail_errno;
4933 env->me_wmutex = OpenMutexA(SYNCHRONIZE, FALSE, env->me_txns->mti_wmname);
4934 if (!env->me_wmutex) goto fail_errno;
4935 #elif defined(MDB_USE_POSIX_SEM)
4936 env->me_rmutex = sem_open(env->me_txns->mti_rmname, 0);
4937 if (env->me_rmutex == SEM_FAILED) goto fail_errno;
4938 env->me_wmutex = sem_open(env->me_txns->mti_wmname, 0);
4939 if (env->me_wmutex == SEM_FAILED) goto fail_errno;
4940 #endif
4941 }
4942 return MDB_SUCCESS;
4943
4944 fail_errno:
4945 rc = ErrCode();
4946 fail:
4947 return rc;
4948 }
4949
4950 /** Only a subset of the @ref mdb_env flags can be changed
4951 * at runtime. Changing other flags requires closing the
4952 * environment and re-opening it with the new flags.
4953 */
4954 #define CHANGEABLE (MDB_NOSYNC|MDB_NOMETASYNC|MDB_MAPASYNC|MDB_NOMEMINIT)
4955 #define CHANGELESS (MDB_FIXEDMAP|MDB_NOSUBDIR|MDB_RDONLY| \
4956 MDB_WRITEMAP|MDB_NOTLS|MDB_NOLOCK|MDB_NORDAHEAD)
4957
4958 #if VALID_FLAGS & PERSISTENT_FLAGS & (CHANGEABLE|CHANGELESS)
4959 # error "Persistent DB flags & env flags overlap, but both go in mm_flags"
4960 #endif
4961
4962 int ESECT
mdb_env_open(MDB_env * env,const char * path,unsigned int flags,mdb_mode_t mode)4963 mdb_env_open(MDB_env *env, const char *path, unsigned int flags, mdb_mode_t mode)
4964 {
4965 int rc, excl = -1;
4966 MDB_name fname;
4967
4968 if (env->me_fd!=INVALID_HANDLE_VALUE || (flags & ~(CHANGEABLE|CHANGELESS)))
4969 return EINVAL;
4970
4971 flags |= env->me_flags;
4972
4973 rc = mdb_fname_init(path, flags, &fname);
4974 if (rc)
4975 return rc;
4976
4977 if (flags & MDB_RDONLY) {
4978 /* silently ignore WRITEMAP when we're only getting read access */
4979 flags &= ~MDB_WRITEMAP;
4980 } else {
4981 if (!((env->me_free_pgs = mdb_midl_alloc(MDB_IDL_UM_MAX)) &&
4982 (env->me_dirty_list = calloc(MDB_IDL_UM_SIZE, sizeof(MDB_ID2)))))
4983 rc = ENOMEM;
4984 }
4985 env->me_flags = flags |= MDB_ENV_ACTIVE;
4986 if (rc)
4987 goto leave;
4988
4989 env->me_path = strdup(path);
4990 env->me_dbxs = calloc(env->me_maxdbs, sizeof(MDB_dbx));
4991 env->me_dbflags = calloc(env->me_maxdbs, sizeof(uint16_t));
4992 env->me_dbiseqs = calloc(env->me_maxdbs, sizeof(unsigned int));
4993 if (!(env->me_dbxs && env->me_path && env->me_dbflags && env->me_dbiseqs)) {
4994 rc = ENOMEM;
4995 goto leave;
4996 }
4997 env->me_dbxs[FREE_DBI].md_cmp = mdb_cmp_long; /* aligned MDB_INTEGERKEY */
4998
4999 /* For RDONLY, get lockfile after we know datafile exists */
5000 if (!(flags & (MDB_RDONLY|MDB_NOLOCK))) {
5001 rc = mdb_env_setup_locks(env, &fname, mode, &excl);
5002 if (rc)
5003 goto leave;
5004 }
5005
5006 rc = mdb_fopen(env, &fname,
5007 (flags & MDB_RDONLY) ? MDB_O_RDONLY : MDB_O_RDWR,
5008 mode, &env->me_fd);
5009 if (rc)
5010 goto leave;
5011
5012 if ((flags & (MDB_RDONLY|MDB_NOLOCK)) == MDB_RDONLY) {
5013 rc = mdb_env_setup_locks(env, &fname, mode, &excl);
5014 if (rc)
5015 goto leave;
5016 }
5017
5018 if ((rc = mdb_env_open2(env)) == MDB_SUCCESS) {
5019 if (!(flags & (MDB_RDONLY|MDB_WRITEMAP))) {
5020 /* Synchronous fd for meta writes. Needed even with
5021 * MDB_NOSYNC/MDB_NOMETASYNC, in case these get reset.
5022 */
5023 rc = mdb_fopen(env, &fname, MDB_O_META, mode, &env->me_mfd);
5024 if (rc)
5025 goto leave;
5026 }
5027 DPRINTF(("opened dbenv %p", (void *) env));
5028 if (excl > 0) {
5029 rc = mdb_env_share_locks(env, &excl);
5030 if (rc)
5031 goto leave;
5032 }
5033 if (!(flags & MDB_RDONLY)) {
5034 MDB_txn *txn;
5035 int tsize = sizeof(MDB_txn), size = tsize + env->me_maxdbs *
5036 (sizeof(MDB_db)+sizeof(MDB_cursor *)+sizeof(unsigned int)+1);
5037 if ((env->me_pbuf = calloc(1, env->me_psize)) &&
5038 (txn = calloc(1, size)))
5039 {
5040 txn->mt_dbs = (MDB_db *)((char *)txn + tsize);
5041 txn->mt_cursors = (MDB_cursor **)(txn->mt_dbs + env->me_maxdbs);
5042 txn->mt_dbiseqs = (unsigned int *)(txn->mt_cursors + env->me_maxdbs);
5043 txn->mt_dbflags = (unsigned char *)(txn->mt_dbiseqs + env->me_maxdbs);
5044 txn->mt_env = env;
5045 txn->mt_dbxs = env->me_dbxs;
5046 txn->mt_flags = MDB_TXN_FINISHED;
5047 env->me_txn0 = txn;
5048 } else {
5049 rc = ENOMEM;
5050 }
5051 }
5052 }
5053
5054 leave:
5055 if (rc) {
5056 mdb_env_close0(env, excl);
5057 }
5058 mdb_fname_destroy(fname);
5059 return rc;
5060 }
5061
5062 /** Destroy resources from mdb_env_open(), clear our readers & DBIs */
5063 static void ESECT
mdb_env_close0(MDB_env * env,int excl)5064 mdb_env_close0(MDB_env *env, int excl)
5065 {
5066 int i;
5067
5068 if (!(env->me_flags & MDB_ENV_ACTIVE))
5069 return;
5070
5071 /* Doing this here since me_dbxs may not exist during mdb_env_close */
5072 if (env->me_dbxs) {
5073 for (i = env->me_maxdbs; --i >= CORE_DBS; )
5074 free(env->me_dbxs[i].md_name.mv_data);
5075 free(env->me_dbxs);
5076 }
5077
5078 free(env->me_pbuf);
5079 free(env->me_dbiseqs);
5080 free(env->me_dbflags);
5081 free(env->me_path);
5082 free(env->me_dirty_list);
5083 free(env->me_txn0);
5084 mdb_midl_free(env->me_free_pgs);
5085
5086 if (env->me_flags & MDB_ENV_TXKEY) {
5087 pthread_key_delete(env->me_txkey);
5088 #ifdef _WIN32
5089 /* Delete our key from the global list */
5090 for (i=0; i<mdb_tls_nkeys; i++)
5091 if (mdb_tls_keys[i] == env->me_txkey) {
5092 mdb_tls_keys[i] = mdb_tls_keys[mdb_tls_nkeys-1];
5093 mdb_tls_nkeys--;
5094 break;
5095 }
5096 #endif
5097 }
5098
5099 if (env->me_map) {
5100 munmap(env->me_map, env->me_mapsize);
5101 }
5102 if (env->me_mfd != INVALID_HANDLE_VALUE)
5103 (void) close(env->me_mfd);
5104 if (env->me_fd != INVALID_HANDLE_VALUE)
5105 (void) close(env->me_fd);
5106 if (env->me_txns) {
5107 MDB_PID_T pid = getpid();
5108 /* Clearing readers is done in this function because
5109 * me_txkey with its destructor must be disabled first.
5110 *
5111 * We skip the the reader mutex, so we touch only
5112 * data owned by this process (me_close_readers and
5113 * our readers), and clear each reader atomically.
5114 */
5115 for (i = env->me_close_readers; --i >= 0; )
5116 if (env->me_txns->mti_readers[i].mr_pid == pid)
5117 env->me_txns->mti_readers[i].mr_pid = 0;
5118 #ifdef _WIN32
5119 if (env->me_rmutex) {
5120 CloseHandle(env->me_rmutex);
5121 if (env->me_wmutex) CloseHandle(env->me_wmutex);
5122 }
5123 /* Windows automatically destroys the mutexes when
5124 * the last handle closes.
5125 */
5126 #elif defined(MDB_USE_POSIX_SEM)
5127 if (env->me_rmutex != SEM_FAILED) {
5128 sem_close(env->me_rmutex);
5129 if (env->me_wmutex != SEM_FAILED)
5130 sem_close(env->me_wmutex);
5131 /* If we have the filelock: If we are the
5132 * only remaining user, clean up semaphores.
5133 */
5134 if (excl == 0)
5135 mdb_env_excl_lock(env, &excl);
5136 if (excl > 0) {
5137 sem_unlink(env->me_txns->mti_rmname);
5138 sem_unlink(env->me_txns->mti_wmname);
5139 }
5140 }
5141 #elif defined(MDB_ROBUST_SUPPORTED)
5142 /* If we have the filelock: If we are the
5143 * only remaining user, clean up robust
5144 * mutexes.
5145 */
5146 if (excl == 0)
5147 mdb_env_excl_lock(env, &excl);
5148 if (excl > 0) {
5149 pthread_mutex_destroy(env->me_txns->mti_rmutex);
5150 pthread_mutex_destroy(env->me_txns->mti_wmutex);
5151 }
5152 #endif
5153 munmap((void *)env->me_txns, (env->me_maxreaders-1)*sizeof(MDB_reader)+sizeof(MDB_txninfo));
5154 }
5155 if (env->me_lfd != INVALID_HANDLE_VALUE) {
5156 #ifdef _WIN32
5157 if (excl >= 0) {
5158 /* Unlock the lockfile. Windows would have unlocked it
5159 * after closing anyway, but not necessarily at once.
5160 */
5161 UnlockFile(env->me_lfd, 0, 0, 1, 0);
5162 }
5163 #endif
5164 (void) close(env->me_lfd);
5165 }
5166
5167 env->me_flags &= ~(MDB_ENV_ACTIVE|MDB_ENV_TXKEY);
5168 }
5169
5170 void ESECT
mdb_env_close(MDB_env * env)5171 mdb_env_close(MDB_env *env)
5172 {
5173 MDB_page *dp;
5174
5175 if (env == NULL)
5176 return;
5177
5178 VGMEMP_DESTROY(env);
5179 while ((dp = env->me_dpages) != NULL) {
5180 VGMEMP_DEFINED(&dp->mp_next, sizeof(dp->mp_next));
5181 env->me_dpages = dp->mp_next;
5182 free(dp);
5183 }
5184
5185 mdb_env_close0(env, 0);
5186 free(env);
5187 }
5188
5189 /** Compare two items pointing at aligned size_t's */
5190 static int
mdb_cmp_long(const MDB_val * a,const MDB_val * b)5191 mdb_cmp_long(const MDB_val *a, const MDB_val *b)
5192 {
5193 return (*(size_t *)a->mv_data < *(size_t *)b->mv_data) ? -1 :
5194 *(size_t *)a->mv_data > *(size_t *)b->mv_data;
5195 }
5196
5197 /** Compare two items pointing at aligned unsigned int's.
5198 *
5199 * This is also set as #MDB_INTEGERDUP|#MDB_DUPFIXED's #MDB_dbx.%md_dcmp,
5200 * but #mdb_cmp_clong() is called instead if the data type is size_t.
5201 */
5202 static int
mdb_cmp_int(const MDB_val * a,const MDB_val * b)5203 mdb_cmp_int(const MDB_val *a, const MDB_val *b)
5204 {
5205 return (*(unsigned int *)a->mv_data < *(unsigned int *)b->mv_data) ? -1 :
5206 *(unsigned int *)a->mv_data > *(unsigned int *)b->mv_data;
5207 }
5208
5209 /** Compare two items pointing at unsigned ints of unknown alignment.
5210 * Nodes and keys are guaranteed to be 2-byte aligned.
5211 */
5212 static int
mdb_cmp_cint(const MDB_val * a,const MDB_val * b)5213 mdb_cmp_cint(const MDB_val *a, const MDB_val *b)
5214 {
5215 #if BYTE_ORDER == LITTLE_ENDIAN
5216 unsigned short *u, *c;
5217 int x;
5218
5219 u = (unsigned short *) ((char *) a->mv_data + a->mv_size);
5220 c = (unsigned short *) ((char *) b->mv_data + a->mv_size);
5221 do {
5222 x = *--u - *--c;
5223 } while(!x && u > (unsigned short *)a->mv_data);
5224 return x;
5225 #else
5226 unsigned short *u, *c, *end;
5227 int x;
5228
5229 end = (unsigned short *) ((char *) a->mv_data + a->mv_size);
5230 u = (unsigned short *)a->mv_data;
5231 c = (unsigned short *)b->mv_data;
5232 do {
5233 x = *u++ - *c++;
5234 } while(!x && u < end);
5235 return x;
5236 #endif
5237 }
5238
5239 /** Compare two items lexically */
5240 static int
mdb_cmp_memn(const MDB_val * a,const MDB_val * b)5241 mdb_cmp_memn(const MDB_val *a, const MDB_val *b)
5242 {
5243 int diff;
5244 ssize_t len_diff;
5245 unsigned int len;
5246
5247 len = a->mv_size;
5248 len_diff = (ssize_t) a->mv_size - (ssize_t) b->mv_size;
5249 if (len_diff > 0) {
5250 len = b->mv_size;
5251 len_diff = 1;
5252 }
5253
5254 diff = memcmp(a->mv_data, b->mv_data, len);
5255 return diff ? diff : len_diff<0 ? -1 : len_diff;
5256 }
5257
5258 /** Compare two items in reverse byte order */
5259 static int
mdb_cmp_memnr(const MDB_val * a,const MDB_val * b)5260 mdb_cmp_memnr(const MDB_val *a, const MDB_val *b)
5261 {
5262 const unsigned char *p1, *p2, *p1_lim;
5263 ssize_t len_diff;
5264 int diff;
5265
5266 p1_lim = (const unsigned char *)a->mv_data;
5267 p1 = (const unsigned char *)a->mv_data + a->mv_size;
5268 p2 = (const unsigned char *)b->mv_data + b->mv_size;
5269
5270 len_diff = (ssize_t) a->mv_size - (ssize_t) b->mv_size;
5271 if (len_diff > 0) {
5272 p1_lim += len_diff;
5273 len_diff = 1;
5274 }
5275
5276 while (p1 > p1_lim) {
5277 diff = *--p1 - *--p2;
5278 if (diff)
5279 return diff;
5280 }
5281 return len_diff<0 ? -1 : len_diff;
5282 }
5283
5284 /** Search for key within a page, using binary search.
5285 * Returns the smallest entry larger or equal to the key.
5286 * If exactp is non-null, stores whether the found entry was an exact match
5287 * in *exactp (1 or 0).
5288 * Updates the cursor index with the index of the found entry.
5289 * If no entry larger or equal to the key is found, returns NULL.
5290 */
5291 static MDB_node *
mdb_node_search(MDB_cursor * mc,MDB_val * key,int * exactp)5292 mdb_node_search(MDB_cursor *mc, MDB_val *key, int *exactp)
5293 {
5294 unsigned int i = 0, nkeys;
5295 int low, high;
5296 int rc = 0;
5297 MDB_page *mp = mc->mc_pg[mc->mc_top];
5298 MDB_node *node = NULL;
5299 MDB_val nodekey;
5300 MDB_cmp_func *cmp;
5301 DKBUF;
5302
5303 nkeys = NUMKEYS(mp);
5304
5305 DPRINTF(("searching %u keys in %s %spage %"Z"u",
5306 nkeys, IS_LEAF(mp) ? "leaf" : "branch", IS_SUBP(mp) ? "sub-" : "",
5307 mdb_dbg_pgno(mp)));
5308
5309 low = IS_LEAF(mp) ? 0 : 1;
5310 high = nkeys - 1;
5311 cmp = mc->mc_dbx->md_cmp;
5312
5313 /* Branch pages have no data, so if using integer keys,
5314 * alignment is guaranteed. Use faster mdb_cmp_int.
5315 */
5316 if (cmp == mdb_cmp_cint && IS_BRANCH(mp)) {
5317 if (NODEPTR(mp, 1)->mn_ksize == sizeof(size_t))
5318 cmp = mdb_cmp_long;
5319 else
5320 cmp = mdb_cmp_int;
5321 }
5322
5323 if (IS_LEAF2(mp)) {
5324 nodekey.mv_size = mc->mc_db->md_pad;
5325 node = NODEPTR(mp, 0); /* fake */
5326 while (low <= high) {
5327 i = (low + high) >> 1;
5328 nodekey.mv_data = LEAF2KEY(mp, i, nodekey.mv_size);
5329 rc = cmp(key, &nodekey);
5330 DPRINTF(("found leaf index %u [%s], rc = %i",
5331 i, DKEY(&nodekey), rc));
5332 if (rc == 0)
5333 break;
5334 if (rc > 0)
5335 low = i + 1;
5336 else
5337 high = i - 1;
5338 }
5339 } else {
5340 while (low <= high) {
5341 i = (low + high) >> 1;
5342
5343 node = NODEPTR(mp, i);
5344 nodekey.mv_size = NODEKSZ(node);
5345 nodekey.mv_data = NODEKEY(node);
5346
5347 rc = cmp(key, &nodekey);
5348 #if MDB_DEBUG
5349 if (IS_LEAF(mp))
5350 DPRINTF(("found leaf index %u [%s], rc = %i",
5351 i, DKEY(&nodekey), rc));
5352 else
5353 DPRINTF(("found branch index %u [%s -> %"Z"u], rc = %i",
5354 i, DKEY(&nodekey), NODEPGNO(node), rc));
5355 #endif
5356 if (rc == 0)
5357 break;
5358 if (rc > 0)
5359 low = i + 1;
5360 else
5361 high = i - 1;
5362 }
5363 }
5364
5365 if (rc > 0) { /* Found entry is less than the key. */
5366 i++; /* Skip to get the smallest entry larger than key. */
5367 if (!IS_LEAF2(mp))
5368 node = NODEPTR(mp, i);
5369 }
5370 if (exactp)
5371 *exactp = (rc == 0 && nkeys > 0);
5372 /* store the key index */
5373 mc->mc_ki[mc->mc_top] = i;
5374 if (i >= nkeys)
5375 /* There is no entry larger or equal to the key. */
5376 return NULL;
5377
5378 /* nodeptr is fake for LEAF2 */
5379 return node;
5380 }
5381
5382 #if 0
5383 static void
5384 mdb_cursor_adjust(MDB_cursor *mc, func)
5385 {
5386 MDB_cursor *m2;
5387
5388 for (m2 = mc->mc_txn->mt_cursors[mc->mc_dbi]; m2; m2=m2->mc_next) {
5389 if (m2->mc_pg[m2->mc_top] == mc->mc_pg[mc->mc_top]) {
5390 func(mc, m2);
5391 }
5392 }
5393 }
5394 #endif
5395
5396 /** Pop a page off the top of the cursor's stack. */
5397 static void
mdb_cursor_pop(MDB_cursor * mc)5398 mdb_cursor_pop(MDB_cursor *mc)
5399 {
5400 if (mc->mc_snum) {
5401 DPRINTF(("popping page %"Z"u off db %d cursor %p",
5402 mc->mc_pg[mc->mc_top]->mp_pgno, DDBI(mc), (void *) mc));
5403
5404 mc->mc_snum--;
5405 if (mc->mc_snum) {
5406 mc->mc_top--;
5407 } else {
5408 mc->mc_flags &= ~C_INITIALIZED;
5409 }
5410 }
5411 }
5412
5413 /** Push a page onto the top of the cursor's stack.
5414 * Set #MDB_TXN_ERROR on failure.
5415 */
5416 static int
mdb_cursor_push(MDB_cursor * mc,MDB_page * mp)5417 mdb_cursor_push(MDB_cursor *mc, MDB_page *mp)
5418 {
5419 DPRINTF(("pushing page %"Z"u on db %d cursor %p", mp->mp_pgno,
5420 DDBI(mc), (void *) mc));
5421
5422 if (mc->mc_snum >= CURSOR_STACK) {
5423 mc->mc_txn->mt_flags |= MDB_TXN_ERROR;
5424 return MDB_CURSOR_FULL;
5425 }
5426
5427 mc->mc_top = mc->mc_snum++;
5428 mc->mc_pg[mc->mc_top] = mp;
5429 mc->mc_ki[mc->mc_top] = 0;
5430
5431 return MDB_SUCCESS;
5432 }
5433
5434 /** Find the address of the page corresponding to a given page number.
5435 * Set #MDB_TXN_ERROR on failure.
5436 * @param[in] mc the cursor accessing the page.
5437 * @param[in] pgno the page number for the page to retrieve.
5438 * @param[out] ret address of a pointer where the page's address will be stored.
5439 * @param[out] lvl dirty_list inheritance level of found page. 1=current txn, 0=mapped page.
5440 * @return 0 on success, non-zero on failure.
5441 */
5442 static int
mdb_page_get(MDB_cursor * mc,pgno_t pgno,MDB_page ** ret,int * lvl)5443 mdb_page_get(MDB_cursor *mc, pgno_t pgno, MDB_page **ret, int *lvl)
5444 {
5445 MDB_txn *txn = mc->mc_txn;
5446 MDB_env *env = txn->mt_env;
5447 MDB_page *p = NULL;
5448 int level;
5449
5450 if (! (txn->mt_flags & (MDB_TXN_RDONLY|MDB_TXN_WRITEMAP))) {
5451 MDB_txn *tx2 = txn;
5452 level = 1;
5453 do {
5454 MDB_ID2L dl = tx2->mt_u.dirty_list;
5455 unsigned x;
5456 /* Spilled pages were dirtied in this txn and flushed
5457 * because the dirty list got full. Bring this page
5458 * back in from the map (but don't unspill it here,
5459 * leave that unless page_touch happens again).
5460 */
5461 if (tx2->mt_spill_pgs) {
5462 MDB_ID pn = pgno << 1;
5463 x = mdb_midl_search(tx2->mt_spill_pgs, pn);
5464 if (x <= tx2->mt_spill_pgs[0] && tx2->mt_spill_pgs[x] == pn) {
5465 p = (MDB_page *)(env->me_map + env->me_psize * pgno);
5466 goto done;
5467 }
5468 }
5469 if (dl[0].mid) {
5470 unsigned x = mdb_mid2l_search(dl, pgno);
5471 if (x <= dl[0].mid && dl[x].mid == pgno) {
5472 p = dl[x].mptr;
5473 goto done;
5474 }
5475 }
5476 level++;
5477 } while ((tx2 = tx2->mt_parent) != NULL);
5478 }
5479
5480 if (pgno < txn->mt_next_pgno) {
5481 level = 0;
5482 p = (MDB_page *)(env->me_map + env->me_psize * pgno);
5483 } else {
5484 DPRINTF(("page %"Z"u not found", pgno));
5485 txn->mt_flags |= MDB_TXN_ERROR;
5486 return MDB_PAGE_NOTFOUND;
5487 }
5488
5489 done:
5490 *ret = p;
5491 if (lvl)
5492 *lvl = level;
5493 return MDB_SUCCESS;
5494 }
5495
5496 /** Finish #mdb_page_search() / #mdb_page_search_lowest().
5497 * The cursor is at the root page, set up the rest of it.
5498 */
5499 static int
mdb_page_search_root(MDB_cursor * mc,MDB_val * key,int flags)5500 mdb_page_search_root(MDB_cursor *mc, MDB_val *key, int flags)
5501 {
5502 MDB_page *mp = mc->mc_pg[mc->mc_top];
5503 int rc;
5504 DKBUF;
5505
5506 while (IS_BRANCH(mp)) {
5507 MDB_node *node;
5508 indx_t i;
5509
5510 DPRINTF(("branch page %"Z"u has %u keys", mp->mp_pgno, NUMKEYS(mp)));
5511 /* Don't assert on branch pages in the FreeDB. We can get here
5512 * while in the process of rebalancing a FreeDB branch page; we must
5513 * let that proceed. ITS#8336
5514 */
5515 mdb_cassert(mc, !mc->mc_dbi || NUMKEYS(mp) > 1);
5516 DPRINTF(("found index 0 to page %"Z"u", NODEPGNO(NODEPTR(mp, 0))));
5517
5518 if (flags & (MDB_PS_FIRST|MDB_PS_LAST)) {
5519 i = 0;
5520 if (flags & MDB_PS_LAST) {
5521 i = NUMKEYS(mp) - 1;
5522 /* if already init'd, see if we're already in right place */
5523 if (mc->mc_flags & C_INITIALIZED) {
5524 if (mc->mc_ki[mc->mc_top] == i) {
5525 mc->mc_top = mc->mc_snum++;
5526 mp = mc->mc_pg[mc->mc_top];
5527 goto ready;
5528 }
5529 }
5530 }
5531 } else {
5532 int exact;
5533 node = mdb_node_search(mc, key, &exact);
5534 if (node == NULL)
5535 i = NUMKEYS(mp) - 1;
5536 else {
5537 i = mc->mc_ki[mc->mc_top];
5538 if (!exact) {
5539 mdb_cassert(mc, i > 0);
5540 i--;
5541 }
5542 }
5543 DPRINTF(("following index %u for key [%s]", i, DKEY(key)));
5544 }
5545
5546 mdb_cassert(mc, i < NUMKEYS(mp));
5547 node = NODEPTR(mp, i);
5548
5549 if ((rc = mdb_page_get(mc, NODEPGNO(node), &mp, NULL)) != 0)
5550 return rc;
5551
5552 mc->mc_ki[mc->mc_top] = i;
5553 if ((rc = mdb_cursor_push(mc, mp)))
5554 return rc;
5555
5556 ready:
5557 if (flags & MDB_PS_MODIFY) {
5558 if ((rc = mdb_page_touch(mc)) != 0)
5559 return rc;
5560 mp = mc->mc_pg[mc->mc_top];
5561 }
5562 }
5563
5564 if (!IS_LEAF(mp)) {
5565 DPRINTF(("internal error, index points to a %02X page!?",
5566 mp->mp_flags));
5567 mc->mc_txn->mt_flags |= MDB_TXN_ERROR;
5568 return MDB_CORRUPTED;
5569 }
5570
5571 DPRINTF(("found leaf page %"Z"u for key [%s]", mp->mp_pgno,
5572 key ? DKEY(key) : "null"));
5573 mc->mc_flags |= C_INITIALIZED;
5574 mc->mc_flags &= ~C_EOF;
5575
5576 return MDB_SUCCESS;
5577 }
5578
5579 /** Search for the lowest key under the current branch page.
5580 * This just bypasses a NUMKEYS check in the current page
5581 * before calling mdb_page_search_root(), because the callers
5582 * are all in situations where the current page is known to
5583 * be underfilled.
5584 */
5585 static int
mdb_page_search_lowest(MDB_cursor * mc)5586 mdb_page_search_lowest(MDB_cursor *mc)
5587 {
5588 MDB_page *mp = mc->mc_pg[mc->mc_top];
5589 MDB_node *node = NODEPTR(mp, 0);
5590 int rc;
5591
5592 if ((rc = mdb_page_get(mc, NODEPGNO(node), &mp, NULL)) != 0)
5593 return rc;
5594
5595 mc->mc_ki[mc->mc_top] = 0;
5596 if ((rc = mdb_cursor_push(mc, mp)))
5597 return rc;
5598 return mdb_page_search_root(mc, NULL, MDB_PS_FIRST);
5599 }
5600
5601 /** Search for the page a given key should be in.
5602 * Push it and its parent pages on the cursor stack.
5603 * @param[in,out] mc the cursor for this operation.
5604 * @param[in] key the key to search for, or NULL for first/last page.
5605 * @param[in] flags If MDB_PS_MODIFY is set, visited pages in the DB
5606 * are touched (updated with new page numbers).
5607 * If MDB_PS_FIRST or MDB_PS_LAST is set, find first or last leaf.
5608 * This is used by #mdb_cursor_first() and #mdb_cursor_last().
5609 * If MDB_PS_ROOTONLY set, just fetch root node, no further lookups.
5610 * @return 0 on success, non-zero on failure.
5611 */
5612 static int
mdb_page_search(MDB_cursor * mc,MDB_val * key,int flags)5613 mdb_page_search(MDB_cursor *mc, MDB_val *key, int flags)
5614 {
5615 int rc;
5616 pgno_t root;
5617
5618 /* Make sure the txn is still viable, then find the root from
5619 * the txn's db table and set it as the root of the cursor's stack.
5620 */
5621 if (mc->mc_txn->mt_flags & MDB_TXN_BLOCKED) {
5622 DPUTS("transaction may not be used now");
5623 return MDB_BAD_TXN;
5624 } else {
5625 /* Make sure we're using an up-to-date root */
5626 if (*mc->mc_dbflag & DB_STALE) {
5627 MDB_cursor mc2;
5628 if (TXN_DBI_CHANGED(mc->mc_txn, mc->mc_dbi))
5629 return MDB_BAD_DBI;
5630 mdb_cursor_init(&mc2, mc->mc_txn, MAIN_DBI, NULL);
5631 rc = mdb_page_search(&mc2, &mc->mc_dbx->md_name, 0);
5632 if (rc)
5633 return rc;
5634 {
5635 MDB_val data;
5636 int exact = 0;
5637 uint16_t flags;
5638 MDB_node *leaf = mdb_node_search(&mc2,
5639 &mc->mc_dbx->md_name, &exact);
5640 if (!exact)
5641 return MDB_NOTFOUND;
5642 if ((leaf->mn_flags & (F_DUPDATA|F_SUBDATA)) != F_SUBDATA)
5643 return MDB_INCOMPATIBLE; /* not a named DB */
5644 rc = mdb_node_read(&mc2, leaf, &data);
5645 if (rc)
5646 return rc;
5647 memcpy(&flags, ((char *) data.mv_data + offsetof(MDB_db, md_flags)),
5648 sizeof(uint16_t));
5649 /* The txn may not know this DBI, or another process may
5650 * have dropped and recreated the DB with other flags.
5651 */
5652 if ((mc->mc_db->md_flags & PERSISTENT_FLAGS) != flags)
5653 return MDB_INCOMPATIBLE;
5654 memcpy(mc->mc_db, data.mv_data, sizeof(MDB_db));
5655 }
5656 *mc->mc_dbflag &= ~DB_STALE;
5657 }
5658 root = mc->mc_db->md_root;
5659
5660 if (root == P_INVALID) { /* Tree is empty. */
5661 DPUTS("tree is empty");
5662 return MDB_NOTFOUND;
5663 }
5664 }
5665
5666 mdb_cassert(mc, root > 1);
5667 if (!mc->mc_pg[0] || mc->mc_pg[0]->mp_pgno != root)
5668 if ((rc = mdb_page_get(mc, root, &mc->mc_pg[0], NULL)) != 0)
5669 return rc;
5670
5671 mc->mc_snum = 1;
5672 mc->mc_top = 0;
5673
5674 DPRINTF(("db %d root page %"Z"u has flags 0x%X",
5675 DDBI(mc), root, mc->mc_pg[0]->mp_flags));
5676
5677 if (flags & MDB_PS_MODIFY) {
5678 if ((rc = mdb_page_touch(mc)))
5679 return rc;
5680 }
5681
5682 if (flags & MDB_PS_ROOTONLY)
5683 return MDB_SUCCESS;
5684
5685 return mdb_page_search_root(mc, key, flags);
5686 }
5687
5688 static int
mdb_ovpage_free(MDB_cursor * mc,MDB_page * mp)5689 mdb_ovpage_free(MDB_cursor *mc, MDB_page *mp)
5690 {
5691 MDB_txn *txn = mc->mc_txn;
5692 pgno_t pg = mp->mp_pgno;
5693 unsigned x = 0, ovpages = mp->mp_pages;
5694 MDB_env *env = txn->mt_env;
5695 MDB_IDL sl = txn->mt_spill_pgs;
5696 MDB_ID pn = pg << 1;
5697 int rc;
5698
5699 DPRINTF(("free ov page %"Z"u (%d)", pg, ovpages));
5700 /* If the page is dirty or on the spill list we just acquired it,
5701 * so we should give it back to our current free list, if any.
5702 * Otherwise put it onto the list of pages we freed in this txn.
5703 *
5704 * Won't create me_pghead: me_pglast must be inited along with it.
5705 * Unsupported in nested txns: They would need to hide the page
5706 * range in ancestor txns' dirty and spilled lists.
5707 */
5708 if (env->me_pghead &&
5709 !txn->mt_parent &&
5710 ((mp->mp_flags & P_DIRTY) ||
5711 (sl && (x = mdb_midl_search(sl, pn)) <= sl[0] && sl[x] == pn)))
5712 {
5713 unsigned i, j;
5714 pgno_t *mop;
5715 MDB_ID2 *dl, ix, iy;
5716 rc = mdb_midl_need(&env->me_pghead, ovpages);
5717 if (rc)
5718 return rc;
5719 if (!(mp->mp_flags & P_DIRTY)) {
5720 /* This page is no longer spilled */
5721 if (x == sl[0])
5722 sl[0]--;
5723 else
5724 sl[x] |= 1;
5725 goto release;
5726 }
5727 /* Remove from dirty list */
5728 dl = txn->mt_u.dirty_list;
5729 x = dl[0].mid--;
5730 for (ix = dl[x]; ix.mptr != mp; ix = iy) {
5731 if (x > 1) {
5732 x--;
5733 iy = dl[x];
5734 dl[x] = ix;
5735 } else {
5736 mdb_cassert(mc, x > 1);
5737 j = ++(dl[0].mid);
5738 dl[j] = ix; /* Unsorted. OK when MDB_TXN_ERROR. */
5739 txn->mt_flags |= MDB_TXN_ERROR;
5740 return MDB_CORRUPTED;
5741 }
5742 }
5743 txn->mt_dirty_room++;
5744 if (!(env->me_flags & MDB_WRITEMAP))
5745 mdb_dpage_free(env, mp);
5746 release:
5747 /* Insert in me_pghead */
5748 mop = env->me_pghead;
5749 j = mop[0] + ovpages;
5750 for (i = mop[0]; i && mop[i] < pg; i--)
5751 mop[j--] = mop[i];
5752 while (j>i)
5753 mop[j--] = pg++;
5754 mop[0] += ovpages;
5755 } else {
5756 rc = mdb_midl_append_range(&txn->mt_free_pgs, pg, ovpages);
5757 if (rc)
5758 return rc;
5759 }
5760 mc->mc_db->md_overflow_pages -= ovpages;
5761 return 0;
5762 }
5763
5764 /** Return the data associated with a given node.
5765 * @param[in] mc The cursor for this operation.
5766 * @param[in] leaf The node being read.
5767 * @param[out] data Updated to point to the node's data.
5768 * @return 0 on success, non-zero on failure.
5769 */
5770 static int
mdb_node_read(MDB_cursor * mc,MDB_node * leaf,MDB_val * data)5771 mdb_node_read(MDB_cursor *mc, MDB_node *leaf, MDB_val *data)
5772 {
5773 MDB_page *omp; /* overflow page */
5774 pgno_t pgno;
5775 int rc;
5776
5777 if (!F_ISSET(leaf->mn_flags, F_BIGDATA)) {
5778 data->mv_size = NODEDSZ(leaf);
5779 data->mv_data = NODEDATA(leaf);
5780 return MDB_SUCCESS;
5781 }
5782
5783 /* Read overflow data.
5784 */
5785 data->mv_size = NODEDSZ(leaf);
5786 memcpy(&pgno, NODEDATA(leaf), sizeof(pgno));
5787 if ((rc = mdb_page_get(mc, pgno, &omp, NULL)) != 0) {
5788 DPRINTF(("read overflow page %"Z"u failed", pgno));
5789 return rc;
5790 }
5791 data->mv_data = METADATA(omp);
5792
5793 return MDB_SUCCESS;
5794 }
5795
5796 int
mdb_get(MDB_txn * txn,MDB_dbi dbi,MDB_val * key,MDB_val * data)5797 mdb_get(MDB_txn *txn, MDB_dbi dbi,
5798 MDB_val *key, MDB_val *data)
5799 {
5800 MDB_cursor mc;
5801 MDB_xcursor mx;
5802 int exact = 0;
5803 DKBUF;
5804
5805 DPRINTF(("===> get db %u key [%s]", dbi, DKEY(key)));
5806
5807 if (!key || !data || !TXN_DBI_EXIST(txn, dbi, DB_USRVALID))
5808 return EINVAL;
5809
5810 if (txn->mt_flags & MDB_TXN_BLOCKED)
5811 return MDB_BAD_TXN;
5812
5813 mdb_cursor_init(&mc, txn, dbi, &mx);
5814 return mdb_cursor_set(&mc, key, data, MDB_SET, &exact);
5815 }
5816
5817 /** Find a sibling for a page.
5818 * Replaces the page at the top of the cursor's stack with the
5819 * specified sibling, if one exists.
5820 * @param[in] mc The cursor for this operation.
5821 * @param[in] move_right Non-zero if the right sibling is requested,
5822 * otherwise the left sibling.
5823 * @return 0 on success, non-zero on failure.
5824 */
5825 static int
mdb_cursor_sibling(MDB_cursor * mc,int move_right)5826 mdb_cursor_sibling(MDB_cursor *mc, int move_right)
5827 {
5828 int rc;
5829 MDB_node *indx;
5830 MDB_page *mp;
5831
5832 if (mc->mc_snum < 2) {
5833 return MDB_NOTFOUND; /* root has no siblings */
5834 }
5835
5836 mdb_cursor_pop(mc);
5837 DPRINTF(("parent page is page %"Z"u, index %u",
5838 mc->mc_pg[mc->mc_top]->mp_pgno, mc->mc_ki[mc->mc_top]));
5839
5840 if (move_right ? (mc->mc_ki[mc->mc_top] + 1u >= NUMKEYS(mc->mc_pg[mc->mc_top]))
5841 : (mc->mc_ki[mc->mc_top] == 0)) {
5842 DPRINTF(("no more keys left, moving to %s sibling",
5843 move_right ? "right" : "left"));
5844 if ((rc = mdb_cursor_sibling(mc, move_right)) != MDB_SUCCESS) {
5845 /* undo cursor_pop before returning */
5846 mc->mc_top++;
5847 mc->mc_snum++;
5848 return rc;
5849 }
5850 } else {
5851 if (move_right)
5852 mc->mc_ki[mc->mc_top]++;
5853 else
5854 mc->mc_ki[mc->mc_top]--;
5855 DPRINTF(("just moving to %s index key %u",
5856 move_right ? "right" : "left", mc->mc_ki[mc->mc_top]));
5857 }
5858 mdb_cassert(mc, IS_BRANCH(mc->mc_pg[mc->mc_top]));
5859
5860 indx = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
5861 if ((rc = mdb_page_get(mc, NODEPGNO(indx), &mp, NULL)) != 0) {
5862 /* mc will be inconsistent if caller does mc_snum++ as above */
5863 mc->mc_flags &= ~(C_INITIALIZED|C_EOF);
5864 return rc;
5865 }
5866
5867 mdb_cursor_push(mc, mp);
5868 if (!move_right)
5869 mc->mc_ki[mc->mc_top] = NUMKEYS(mp)-1;
5870
5871 return MDB_SUCCESS;
5872 }
5873
5874 /** Move the cursor to the next data item. */
5875 static int
mdb_cursor_next(MDB_cursor * mc,MDB_val * key,MDB_val * data,MDB_cursor_op op)5876 mdb_cursor_next(MDB_cursor *mc, MDB_val *key, MDB_val *data, MDB_cursor_op op)
5877 {
5878 MDB_page *mp;
5879 MDB_node *leaf;
5880 int rc;
5881
5882 if ((mc->mc_flags & C_DEL && op == MDB_NEXT_DUP))
5883 return MDB_NOTFOUND;
5884
5885 if (!(mc->mc_flags & C_INITIALIZED))
5886 return mdb_cursor_first(mc, key, data);
5887
5888 mp = mc->mc_pg[mc->mc_top];
5889
5890 if (mc->mc_flags & C_EOF) {
5891 if (mc->mc_ki[mc->mc_top] >= NUMKEYS(mp)-1)
5892 return MDB_NOTFOUND;
5893 mc->mc_flags ^= C_EOF;
5894 }
5895
5896 if (mc->mc_db->md_flags & MDB_DUPSORT) {
5897 leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
5898 if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
5899 if (op == MDB_NEXT || op == MDB_NEXT_DUP) {
5900 rc = mdb_cursor_next(&mc->mc_xcursor->mx_cursor, data, NULL, MDB_NEXT);
5901 if (op != MDB_NEXT || rc != MDB_NOTFOUND) {
5902 if (rc == MDB_SUCCESS)
5903 MDB_GET_KEY(leaf, key);
5904 return rc;
5905 }
5906 }
5907 } else {
5908 mc->mc_xcursor->mx_cursor.mc_flags &= ~(C_INITIALIZED|C_EOF);
5909 if (op == MDB_NEXT_DUP)
5910 return MDB_NOTFOUND;
5911 }
5912 }
5913
5914 DPRINTF(("cursor_next: top page is %"Z"u in cursor %p",
5915 mdb_dbg_pgno(mp), (void *) mc));
5916 if (mc->mc_flags & C_DEL) {
5917 mc->mc_flags ^= C_DEL;
5918 goto skip;
5919 }
5920
5921 if (mc->mc_ki[mc->mc_top] + 1u >= NUMKEYS(mp)) {
5922 DPUTS("=====> move to next sibling page");
5923 if ((rc = mdb_cursor_sibling(mc, 1)) != MDB_SUCCESS) {
5924 mc->mc_flags |= C_EOF;
5925 return rc;
5926 }
5927 mp = mc->mc_pg[mc->mc_top];
5928 DPRINTF(("next page is %"Z"u, key index %u", mp->mp_pgno, mc->mc_ki[mc->mc_top]));
5929 } else
5930 mc->mc_ki[mc->mc_top]++;
5931
5932 skip:
5933 DPRINTF(("==> cursor points to page %"Z"u with %u keys, key index %u",
5934 mdb_dbg_pgno(mp), NUMKEYS(mp), mc->mc_ki[mc->mc_top]));
5935
5936 if (IS_LEAF2(mp)) {
5937 key->mv_size = mc->mc_db->md_pad;
5938 key->mv_data = LEAF2KEY(mp, mc->mc_ki[mc->mc_top], key->mv_size);
5939 return MDB_SUCCESS;
5940 }
5941
5942 mdb_cassert(mc, IS_LEAF(mp));
5943 leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
5944
5945 if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
5946 mdb_xcursor_init1(mc, leaf);
5947 rc = mdb_cursor_first(&mc->mc_xcursor->mx_cursor, data, NULL);
5948 if (rc != MDB_SUCCESS)
5949 return rc;
5950 } else if (data) {
5951 if ((rc = mdb_node_read(mc, leaf, data)) != MDB_SUCCESS)
5952 return rc;
5953 }
5954
5955 MDB_GET_KEY(leaf, key);
5956 return MDB_SUCCESS;
5957 }
5958
5959 /** Move the cursor to the previous data item. */
5960 static int
mdb_cursor_prev(MDB_cursor * mc,MDB_val * key,MDB_val * data,MDB_cursor_op op)5961 mdb_cursor_prev(MDB_cursor *mc, MDB_val *key, MDB_val *data, MDB_cursor_op op)
5962 {
5963 MDB_page *mp;
5964 MDB_node *leaf;
5965 int rc;
5966
5967 if (!(mc->mc_flags & C_INITIALIZED)) {
5968 rc = mdb_cursor_last(mc, key, data);
5969 if (rc)
5970 return rc;
5971 mc->mc_ki[mc->mc_top]++;
5972 }
5973
5974 mp = mc->mc_pg[mc->mc_top];
5975
5976 if ((mc->mc_db->md_flags & MDB_DUPSORT) &&
5977 mc->mc_ki[mc->mc_top] < NUMKEYS(mp)) {
5978 leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
5979 if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
5980 if (op == MDB_PREV || op == MDB_PREV_DUP) {
5981 rc = mdb_cursor_prev(&mc->mc_xcursor->mx_cursor, data, NULL, MDB_PREV);
5982 if (op != MDB_PREV || rc != MDB_NOTFOUND) {
5983 if (rc == MDB_SUCCESS) {
5984 MDB_GET_KEY(leaf, key);
5985 mc->mc_flags &= ~C_EOF;
5986 }
5987 return rc;
5988 }
5989 }
5990 } else {
5991 mc->mc_xcursor->mx_cursor.mc_flags &= ~(C_INITIALIZED|C_EOF);
5992 if (op == MDB_PREV_DUP)
5993 return MDB_NOTFOUND;
5994 }
5995 }
5996
5997 DPRINTF(("cursor_prev: top page is %"Z"u in cursor %p",
5998 mdb_dbg_pgno(mp), (void *) mc));
5999
6000 mc->mc_flags &= ~(C_EOF|C_DEL);
6001
6002 if (mc->mc_ki[mc->mc_top] == 0) {
6003 DPUTS("=====> move to prev sibling page");
6004 if ((rc = mdb_cursor_sibling(mc, 0)) != MDB_SUCCESS) {
6005 return rc;
6006 }
6007 mp = mc->mc_pg[mc->mc_top];
6008 mc->mc_ki[mc->mc_top] = NUMKEYS(mp) - 1;
6009 DPRINTF(("prev page is %"Z"u, key index %u", mp->mp_pgno, mc->mc_ki[mc->mc_top]));
6010 } else
6011 mc->mc_ki[mc->mc_top]--;
6012
6013 DPRINTF(("==> cursor points to page %"Z"u with %u keys, key index %u",
6014 mdb_dbg_pgno(mp), NUMKEYS(mp), mc->mc_ki[mc->mc_top]));
6015
6016 if (!IS_LEAF(mp))
6017 return MDB_CORRUPTED;
6018
6019 if (IS_LEAF2(mp)) {
6020 key->mv_size = mc->mc_db->md_pad;
6021 key->mv_data = LEAF2KEY(mp, mc->mc_ki[mc->mc_top], key->mv_size);
6022 return MDB_SUCCESS;
6023 }
6024
6025 leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
6026
6027 if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
6028 mdb_xcursor_init1(mc, leaf);
6029 rc = mdb_cursor_last(&mc->mc_xcursor->mx_cursor, data, NULL);
6030 if (rc != MDB_SUCCESS)
6031 return rc;
6032 } else if (data) {
6033 if ((rc = mdb_node_read(mc, leaf, data)) != MDB_SUCCESS)
6034 return rc;
6035 }
6036
6037 MDB_GET_KEY(leaf, key);
6038 return MDB_SUCCESS;
6039 }
6040
6041 /** Set the cursor on a specific data item. */
6042 static int
mdb_cursor_set(MDB_cursor * mc,MDB_val * key,MDB_val * data,MDB_cursor_op op,int * exactp)6043 mdb_cursor_set(MDB_cursor *mc, MDB_val *key, MDB_val *data,
6044 MDB_cursor_op op, int *exactp)
6045 {
6046 int rc;
6047 MDB_page *mp;
6048 MDB_node *leaf = NULL;
6049 DKBUF;
6050
6051 if (key->mv_size == 0)
6052 return MDB_BAD_VALSIZE;
6053
6054 if (mc->mc_xcursor)
6055 mc->mc_xcursor->mx_cursor.mc_flags &= ~(C_INITIALIZED|C_EOF);
6056
6057 /* See if we're already on the right page */
6058 if (mc->mc_flags & C_INITIALIZED) {
6059 MDB_val nodekey;
6060
6061 mp = mc->mc_pg[mc->mc_top];
6062 if (!NUMKEYS(mp)) {
6063 mc->mc_ki[mc->mc_top] = 0;
6064 return MDB_NOTFOUND;
6065 }
6066 if (mp->mp_flags & P_LEAF2) {
6067 nodekey.mv_size = mc->mc_db->md_pad;
6068 nodekey.mv_data = LEAF2KEY(mp, 0, nodekey.mv_size);
6069 } else {
6070 leaf = NODEPTR(mp, 0);
6071 MDB_GET_KEY2(leaf, nodekey);
6072 }
6073 rc = mc->mc_dbx->md_cmp(key, &nodekey);
6074 if (rc == 0) {
6075 /* Probably happens rarely, but first node on the page
6076 * was the one we wanted.
6077 */
6078 mc->mc_ki[mc->mc_top] = 0;
6079 if (exactp)
6080 *exactp = 1;
6081 goto set1;
6082 }
6083 if (rc > 0) {
6084 unsigned int i;
6085 unsigned int nkeys = NUMKEYS(mp);
6086 if (nkeys > 1) {
6087 if (mp->mp_flags & P_LEAF2) {
6088 nodekey.mv_data = LEAF2KEY(mp,
6089 nkeys-1, nodekey.mv_size);
6090 } else {
6091 leaf = NODEPTR(mp, nkeys-1);
6092 MDB_GET_KEY2(leaf, nodekey);
6093 }
6094 rc = mc->mc_dbx->md_cmp(key, &nodekey);
6095 if (rc == 0) {
6096 /* last node was the one we wanted */
6097 mc->mc_ki[mc->mc_top] = nkeys-1;
6098 if (exactp)
6099 *exactp = 1;
6100 goto set1;
6101 }
6102 if (rc < 0) {
6103 if (mc->mc_ki[mc->mc_top] < NUMKEYS(mp)) {
6104 /* This is definitely the right page, skip search_page */
6105 if (mp->mp_flags & P_LEAF2) {
6106 nodekey.mv_data = LEAF2KEY(mp,
6107 mc->mc_ki[mc->mc_top], nodekey.mv_size);
6108 } else {
6109 leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
6110 MDB_GET_KEY2(leaf, nodekey);
6111 }
6112 rc = mc->mc_dbx->md_cmp(key, &nodekey);
6113 if (rc == 0) {
6114 /* current node was the one we wanted */
6115 if (exactp)
6116 *exactp = 1;
6117 goto set1;
6118 }
6119 }
6120 rc = 0;
6121 mc->mc_flags &= ~C_EOF;
6122 goto set2;
6123 }
6124 }
6125 /* If any parents have right-sibs, search.
6126 * Otherwise, there's nothing further.
6127 */
6128 for (i=0; i<mc->mc_top; i++)
6129 if (mc->mc_ki[i] <
6130 NUMKEYS(mc->mc_pg[i])-1)
6131 break;
6132 if (i == mc->mc_top) {
6133 /* There are no other pages */
6134 mc->mc_ki[mc->mc_top] = nkeys;
6135 return MDB_NOTFOUND;
6136 }
6137 }
6138 if (!mc->mc_top) {
6139 /* There are no other pages */
6140 mc->mc_ki[mc->mc_top] = 0;
6141 if (op == MDB_SET_RANGE && !exactp) {
6142 rc = 0;
6143 goto set1;
6144 } else
6145 return MDB_NOTFOUND;
6146 }
6147 } else {
6148 mc->mc_pg[0] = 0;
6149 }
6150
6151 rc = mdb_page_search(mc, key, 0);
6152 if (rc != MDB_SUCCESS)
6153 return rc;
6154
6155 mp = mc->mc_pg[mc->mc_top];
6156 mdb_cassert(mc, IS_LEAF(mp));
6157
6158 set2:
6159 leaf = mdb_node_search(mc, key, exactp);
6160 if (exactp != NULL && !*exactp) {
6161 /* MDB_SET specified and not an exact match. */
6162 return MDB_NOTFOUND;
6163 }
6164
6165 if (leaf == NULL) {
6166 DPUTS("===> inexact leaf not found, goto sibling");
6167 if ((rc = mdb_cursor_sibling(mc, 1)) != MDB_SUCCESS) {
6168 mc->mc_flags |= C_EOF;
6169 return rc; /* no entries matched */
6170 }
6171 mp = mc->mc_pg[mc->mc_top];
6172 mdb_cassert(mc, IS_LEAF(mp));
6173 leaf = NODEPTR(mp, 0);
6174 }
6175
6176 set1:
6177 mc->mc_flags |= C_INITIALIZED;
6178 mc->mc_flags &= ~C_EOF;
6179
6180 if (IS_LEAF2(mp)) {
6181 if (op == MDB_SET_RANGE || op == MDB_SET_KEY) {
6182 key->mv_size = mc->mc_db->md_pad;
6183 key->mv_data = LEAF2KEY(mp, mc->mc_ki[mc->mc_top], key->mv_size);
6184 }
6185 return MDB_SUCCESS;
6186 }
6187
6188 if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
6189 mdb_xcursor_init1(mc, leaf);
6190 if (op == MDB_SET || op == MDB_SET_KEY || op == MDB_SET_RANGE) {
6191 rc = mdb_cursor_first(&mc->mc_xcursor->mx_cursor, data, NULL);
6192 } else {
6193 int ex2, *ex2p;
6194 if (op == MDB_GET_BOTH) {
6195 ex2p = &ex2;
6196 ex2 = 0;
6197 } else {
6198 ex2p = NULL;
6199 }
6200 rc = mdb_cursor_set(&mc->mc_xcursor->mx_cursor, data, NULL, MDB_SET_RANGE, ex2p);
6201 if (rc != MDB_SUCCESS)
6202 return rc;
6203 }
6204 } else if (data) {
6205 if (op == MDB_GET_BOTH || op == MDB_GET_BOTH_RANGE) {
6206 MDB_val olddata;
6207 MDB_cmp_func *dcmp;
6208 if ((rc = mdb_node_read(mc, leaf, &olddata)) != MDB_SUCCESS)
6209 return rc;
6210 dcmp = mc->mc_dbx->md_dcmp;
6211 #if UINT_MAX < SIZE_MAX
6212 if (dcmp == mdb_cmp_int && olddata.mv_size == sizeof(size_t))
6213 dcmp = mdb_cmp_clong;
6214 #endif
6215 rc = dcmp(data, &olddata);
6216 if (rc) {
6217 if (op == MDB_GET_BOTH || rc > 0)
6218 return MDB_NOTFOUND;
6219 rc = 0;
6220 }
6221 *data = olddata;
6222
6223 } else {
6224 if (mc->mc_xcursor)
6225 mc->mc_xcursor->mx_cursor.mc_flags &= ~(C_INITIALIZED|C_EOF);
6226 if ((rc = mdb_node_read(mc, leaf, data)) != MDB_SUCCESS)
6227 return rc;
6228 }
6229 }
6230
6231 /* The key already matches in all other cases */
6232 if (op == MDB_SET_RANGE || op == MDB_SET_KEY)
6233 MDB_GET_KEY(leaf, key);
6234 DPRINTF(("==> cursor placed on key [%s]", DKEY(key)));
6235
6236 return rc;
6237 }
6238
6239 /** Move the cursor to the first item in the database. */
6240 static int
mdb_cursor_first(MDB_cursor * mc,MDB_val * key,MDB_val * data)6241 mdb_cursor_first(MDB_cursor *mc, MDB_val *key, MDB_val *data)
6242 {
6243 int rc;
6244 MDB_node *leaf;
6245
6246 if (mc->mc_xcursor)
6247 mc->mc_xcursor->mx_cursor.mc_flags &= ~(C_INITIALIZED|C_EOF);
6248
6249 if (!(mc->mc_flags & C_INITIALIZED) || mc->mc_top) {
6250 rc = mdb_page_search(mc, NULL, MDB_PS_FIRST);
6251 if (rc != MDB_SUCCESS)
6252 return rc;
6253 }
6254 mdb_cassert(mc, IS_LEAF(mc->mc_pg[mc->mc_top]));
6255
6256 leaf = NODEPTR(mc->mc_pg[mc->mc_top], 0);
6257 mc->mc_flags |= C_INITIALIZED;
6258 mc->mc_flags &= ~C_EOF;
6259
6260 mc->mc_ki[mc->mc_top] = 0;
6261
6262 if (IS_LEAF2(mc->mc_pg[mc->mc_top])) {
6263 if ( key ) {
6264 key->mv_size = mc->mc_db->md_pad;
6265 key->mv_data = LEAF2KEY(mc->mc_pg[mc->mc_top], 0, key->mv_size);
6266 }
6267 return MDB_SUCCESS;
6268 }
6269
6270 if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
6271 mdb_xcursor_init1(mc, leaf);
6272 rc = mdb_cursor_first(&mc->mc_xcursor->mx_cursor, data, NULL);
6273 if (rc)
6274 return rc;
6275 } else if (data) {
6276 if ((rc = mdb_node_read(mc, leaf, data)) != MDB_SUCCESS)
6277 return rc;
6278 }
6279
6280 MDB_GET_KEY(leaf, key);
6281 return MDB_SUCCESS;
6282 }
6283
6284 /** Move the cursor to the last item in the database. */
6285 static int
mdb_cursor_last(MDB_cursor * mc,MDB_val * key,MDB_val * data)6286 mdb_cursor_last(MDB_cursor *mc, MDB_val *key, MDB_val *data)
6287 {
6288 int rc;
6289 MDB_node *leaf;
6290
6291 if (mc->mc_xcursor)
6292 mc->mc_xcursor->mx_cursor.mc_flags &= ~(C_INITIALIZED|C_EOF);
6293
6294 if (!(mc->mc_flags & C_INITIALIZED) || mc->mc_top) {
6295 rc = mdb_page_search(mc, NULL, MDB_PS_LAST);
6296 if (rc != MDB_SUCCESS)
6297 return rc;
6298 }
6299 mdb_cassert(mc, IS_LEAF(mc->mc_pg[mc->mc_top]));
6300
6301 mc->mc_ki[mc->mc_top] = NUMKEYS(mc->mc_pg[mc->mc_top]) - 1;
6302 mc->mc_flags |= C_INITIALIZED|C_EOF;
6303 leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
6304
6305 if (IS_LEAF2(mc->mc_pg[mc->mc_top])) {
6306 if (key) {
6307 key->mv_size = mc->mc_db->md_pad;
6308 key->mv_data = LEAF2KEY(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top], key->mv_size);
6309 }
6310 return MDB_SUCCESS;
6311 }
6312
6313 if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
6314 mdb_xcursor_init1(mc, leaf);
6315 rc = mdb_cursor_last(&mc->mc_xcursor->mx_cursor, data, NULL);
6316 if (rc)
6317 return rc;
6318 } else if (data) {
6319 if ((rc = mdb_node_read(mc, leaf, data)) != MDB_SUCCESS)
6320 return rc;
6321 }
6322
6323 MDB_GET_KEY(leaf, key);
6324 return MDB_SUCCESS;
6325 }
6326
6327 int
mdb_cursor_get(MDB_cursor * mc,MDB_val * key,MDB_val * data,MDB_cursor_op op)6328 mdb_cursor_get(MDB_cursor *mc, MDB_val *key, MDB_val *data,
6329 MDB_cursor_op op)
6330 {
6331 int rc;
6332 int exact = 0;
6333 int (*mfunc)(MDB_cursor *mc, MDB_val *key, MDB_val *data);
6334
6335 if (mc == NULL)
6336 return EINVAL;
6337
6338 if (mc->mc_txn->mt_flags & MDB_TXN_BLOCKED)
6339 return MDB_BAD_TXN;
6340
6341 switch (op) {
6342 case MDB_GET_CURRENT:
6343 if (!(mc->mc_flags & C_INITIALIZED)) {
6344 rc = EINVAL;
6345 } else {
6346 MDB_page *mp = mc->mc_pg[mc->mc_top];
6347 int nkeys = NUMKEYS(mp);
6348 if (!nkeys || mc->mc_ki[mc->mc_top] >= nkeys) {
6349 mc->mc_ki[mc->mc_top] = nkeys;
6350 rc = MDB_NOTFOUND;
6351 break;
6352 }
6353 rc = MDB_SUCCESS;
6354 if (IS_LEAF2(mp)) {
6355 key->mv_size = mc->mc_db->md_pad;
6356 key->mv_data = LEAF2KEY(mp, mc->mc_ki[mc->mc_top], key->mv_size);
6357 } else {
6358 MDB_node *leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
6359 MDB_GET_KEY(leaf, key);
6360 if (data) {
6361 if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
6362 rc = mdb_cursor_get(&mc->mc_xcursor->mx_cursor, data, NULL, MDB_GET_CURRENT);
6363 } else {
6364 rc = mdb_node_read(mc, leaf, data);
6365 }
6366 }
6367 }
6368 }
6369 break;
6370 case MDB_GET_BOTH:
6371 case MDB_GET_BOTH_RANGE:
6372 if (data == NULL) {
6373 rc = EINVAL;
6374 break;
6375 }
6376 if (mc->mc_xcursor == NULL) {
6377 rc = MDB_INCOMPATIBLE;
6378 break;
6379 }
6380 /* FALLTHRU */
6381 case MDB_SET:
6382 case MDB_SET_KEY:
6383 case MDB_SET_RANGE:
6384 if (key == NULL) {
6385 rc = EINVAL;
6386 } else {
6387 rc = mdb_cursor_set(mc, key, data, op,
6388 op == MDB_SET_RANGE ? NULL : &exact);
6389 }
6390 break;
6391 case MDB_GET_MULTIPLE:
6392 if (data == NULL || !(mc->mc_flags & C_INITIALIZED)) {
6393 rc = EINVAL;
6394 break;
6395 }
6396 if (!(mc->mc_db->md_flags & MDB_DUPFIXED)) {
6397 rc = MDB_INCOMPATIBLE;
6398 break;
6399 }
6400 rc = MDB_SUCCESS;
6401 if (!(mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED) ||
6402 (mc->mc_xcursor->mx_cursor.mc_flags & C_EOF))
6403 break;
6404 goto fetchm;
6405 case MDB_NEXT_MULTIPLE:
6406 if (data == NULL) {
6407 rc = EINVAL;
6408 break;
6409 }
6410 if (!(mc->mc_db->md_flags & MDB_DUPFIXED)) {
6411 rc = MDB_INCOMPATIBLE;
6412 break;
6413 }
6414 rc = mdb_cursor_next(mc, key, data, MDB_NEXT_DUP);
6415 if (rc == MDB_SUCCESS) {
6416 if (mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED) {
6417 MDB_cursor *mx;
6418 fetchm:
6419 mx = &mc->mc_xcursor->mx_cursor;
6420 data->mv_size = NUMKEYS(mx->mc_pg[mx->mc_top]) *
6421 mx->mc_db->md_pad;
6422 data->mv_data = METADATA(mx->mc_pg[mx->mc_top]);
6423 mx->mc_ki[mx->mc_top] = NUMKEYS(mx->mc_pg[mx->mc_top])-1;
6424 } else {
6425 rc = MDB_NOTFOUND;
6426 }
6427 }
6428 break;
6429 case MDB_PREV_MULTIPLE:
6430 if (data == NULL) {
6431 rc = EINVAL;
6432 break;
6433 }
6434 if (!(mc->mc_db->md_flags & MDB_DUPFIXED)) {
6435 rc = MDB_INCOMPATIBLE;
6436 break;
6437 }
6438 if (!(mc->mc_flags & C_INITIALIZED))
6439 rc = mdb_cursor_last(mc, key, data);
6440 else
6441 rc = MDB_SUCCESS;
6442 if (rc == MDB_SUCCESS) {
6443 MDB_cursor *mx = &mc->mc_xcursor->mx_cursor;
6444 if (mx->mc_flags & C_INITIALIZED) {
6445 rc = mdb_cursor_sibling(mx, 0);
6446 if (rc == MDB_SUCCESS)
6447 goto fetchm;
6448 } else {
6449 rc = MDB_NOTFOUND;
6450 }
6451 }
6452 break;
6453 case MDB_NEXT:
6454 case MDB_NEXT_DUP:
6455 case MDB_NEXT_NODUP:
6456 rc = mdb_cursor_next(mc, key, data, op);
6457 break;
6458 case MDB_PREV:
6459 case MDB_PREV_DUP:
6460 case MDB_PREV_NODUP:
6461 rc = mdb_cursor_prev(mc, key, data, op);
6462 break;
6463 case MDB_FIRST:
6464 rc = mdb_cursor_first(mc, key, data);
6465 break;
6466 case MDB_FIRST_DUP:
6467 mfunc = mdb_cursor_first;
6468 mmove:
6469 if (data == NULL || !(mc->mc_flags & C_INITIALIZED)) {
6470 rc = EINVAL;
6471 break;
6472 }
6473 if (mc->mc_xcursor == NULL) {
6474 rc = MDB_INCOMPATIBLE;
6475 break;
6476 }
6477 if (mc->mc_ki[mc->mc_top] >= NUMKEYS(mc->mc_pg[mc->mc_top])) {
6478 mc->mc_ki[mc->mc_top] = NUMKEYS(mc->mc_pg[mc->mc_top]);
6479 rc = MDB_NOTFOUND;
6480 break;
6481 }
6482 {
6483 MDB_node *leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
6484 if (!F_ISSET(leaf->mn_flags, F_DUPDATA)) {
6485 MDB_GET_KEY(leaf, key);
6486 rc = mdb_node_read(mc, leaf, data);
6487 break;
6488 }
6489 }
6490 if (!(mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED)) {
6491 rc = EINVAL;
6492 break;
6493 }
6494 rc = mfunc(&mc->mc_xcursor->mx_cursor, data, NULL);
6495 break;
6496 case MDB_LAST:
6497 rc = mdb_cursor_last(mc, key, data);
6498 break;
6499 case MDB_LAST_DUP:
6500 mfunc = mdb_cursor_last;
6501 goto mmove;
6502 default:
6503 DPRINTF(("unhandled/unimplemented cursor operation %u", op));
6504 rc = EINVAL;
6505 break;
6506 }
6507
6508 if (mc->mc_flags & C_DEL)
6509 mc->mc_flags ^= C_DEL;
6510
6511 return rc;
6512 }
6513
6514 /** Touch all the pages in the cursor stack. Set mc_top.
6515 * Makes sure all the pages are writable, before attempting a write operation.
6516 * @param[in] mc The cursor to operate on.
6517 */
6518 static int
mdb_cursor_touch(MDB_cursor * mc)6519 mdb_cursor_touch(MDB_cursor *mc)
6520 {
6521 int rc = MDB_SUCCESS;
6522
6523 if (mc->mc_dbi >= CORE_DBS && !(*mc->mc_dbflag & (DB_DIRTY|DB_DUPDATA))) {
6524 /* Touch DB record of named DB */
6525 MDB_cursor mc2;
6526 MDB_xcursor mcx;
6527 if (TXN_DBI_CHANGED(mc->mc_txn, mc->mc_dbi))
6528 return MDB_BAD_DBI;
6529 mdb_cursor_init(&mc2, mc->mc_txn, MAIN_DBI, &mcx);
6530 rc = mdb_page_search(&mc2, &mc->mc_dbx->md_name, MDB_PS_MODIFY);
6531 if (rc)
6532 return rc;
6533 *mc->mc_dbflag |= DB_DIRTY;
6534 }
6535 mc->mc_top = 0;
6536 if (mc->mc_snum) {
6537 do {
6538 rc = mdb_page_touch(mc);
6539 } while (!rc && ++(mc->mc_top) < mc->mc_snum);
6540 mc->mc_top = mc->mc_snum-1;
6541 }
6542 return rc;
6543 }
6544
6545 /** Do not spill pages to disk if txn is getting full, may fail instead */
6546 #define MDB_NOSPILL 0x8000
6547
6548 int
mdb_cursor_put(MDB_cursor * mc,MDB_val * key,MDB_val * data,unsigned int flags)6549 mdb_cursor_put(MDB_cursor *mc, MDB_val *key, MDB_val *data,
6550 unsigned int flags)
6551 {
6552 MDB_env *env;
6553 MDB_node *leaf = NULL;
6554 MDB_page *fp, *mp, *sub_root = NULL;
6555 uint16_t fp_flags;
6556 MDB_val xdata, *rdata, dkey, olddata;
6557 MDB_db dummy;
6558 int do_sub = 0, insert_key, insert_data;
6559 unsigned int mcount = 0, dcount = 0, nospill;
6560 size_t nsize;
6561 int rc, rc2;
6562 unsigned int nflags;
6563 DKBUF;
6564
6565 if (mc == NULL || key == NULL)
6566 return EINVAL;
6567
6568 env = mc->mc_txn->mt_env;
6569
6570 /* Check this first so counter will always be zero on any
6571 * early failures.
6572 */
6573 if (flags & MDB_MULTIPLE) {
6574 dcount = data[1].mv_size;
6575 data[1].mv_size = 0;
6576 if (!F_ISSET(mc->mc_db->md_flags, MDB_DUPFIXED))
6577 return MDB_INCOMPATIBLE;
6578 }
6579
6580 nospill = flags & MDB_NOSPILL;
6581 flags &= ~MDB_NOSPILL;
6582
6583 if (mc->mc_txn->mt_flags & (MDB_TXN_RDONLY|MDB_TXN_BLOCKED))
6584 return (mc->mc_txn->mt_flags & MDB_TXN_RDONLY) ? EACCES : MDB_BAD_TXN;
6585
6586 if (key->mv_size-1 >= ENV_MAXKEY(env))
6587 return MDB_BAD_VALSIZE;
6588
6589 #if SIZE_MAX > MAXDATASIZE
6590 if (data->mv_size > ((mc->mc_db->md_flags & MDB_DUPSORT) ? ENV_MAXKEY(env) : MAXDATASIZE))
6591 return MDB_BAD_VALSIZE;
6592 #else
6593 if ((mc->mc_db->md_flags & MDB_DUPSORT) && data->mv_size > ENV_MAXKEY(env))
6594 return MDB_BAD_VALSIZE;
6595 #endif
6596
6597 DPRINTF(("==> put db %d key [%s], size %"Z"u, data size %"Z"u",
6598 DDBI(mc), DKEY(key), key ? key->mv_size : 0, data->mv_size));
6599
6600 dkey.mv_size = 0;
6601
6602 if (flags & MDB_CURRENT) {
6603 if (!(mc->mc_flags & C_INITIALIZED))
6604 return EINVAL;
6605 rc = MDB_SUCCESS;
6606 } else if (mc->mc_db->md_root == P_INVALID) {
6607 /* new database, cursor has nothing to point to */
6608 mc->mc_snum = 0;
6609 mc->mc_top = 0;
6610 mc->mc_flags &= ~C_INITIALIZED;
6611 rc = MDB_NO_ROOT;
6612 } else {
6613 int exact = 0;
6614 MDB_val d2;
6615 if (flags & MDB_APPEND) {
6616 MDB_val k2;
6617 rc = mdb_cursor_last(mc, &k2, &d2);
6618 if (rc == 0) {
6619 rc = mc->mc_dbx->md_cmp(key, &k2);
6620 if (rc > 0) {
6621 rc = MDB_NOTFOUND;
6622 mc->mc_ki[mc->mc_top]++;
6623 } else {
6624 /* new key is <= last key */
6625 rc = MDB_KEYEXIST;
6626 }
6627 }
6628 } else {
6629 rc = mdb_cursor_set(mc, key, &d2, MDB_SET, &exact);
6630 }
6631 if ((flags & MDB_NOOVERWRITE) && rc == 0) {
6632 DPRINTF(("duplicate key [%s]", DKEY(key)));
6633 *data = d2;
6634 return MDB_KEYEXIST;
6635 }
6636 if (rc && rc != MDB_NOTFOUND)
6637 return rc;
6638 }
6639
6640 if (mc->mc_flags & C_DEL)
6641 mc->mc_flags ^= C_DEL;
6642
6643 /* Cursor is positioned, check for room in the dirty list */
6644 if (!nospill) {
6645 if (flags & MDB_MULTIPLE) {
6646 rdata = &xdata;
6647 xdata.mv_size = data->mv_size * dcount;
6648 } else {
6649 rdata = data;
6650 }
6651 if ((rc2 = mdb_page_spill(mc, key, rdata)))
6652 return rc2;
6653 }
6654
6655 if (rc == MDB_NO_ROOT) {
6656 MDB_page *np;
6657 /* new database, write a root leaf page */
6658 DPUTS("allocating new root leaf page");
6659 if ((rc2 = mdb_page_new(mc, P_LEAF, 1, &np))) {
6660 return rc2;
6661 }
6662 mdb_cursor_push(mc, np);
6663 mc->mc_db->md_root = np->mp_pgno;
6664 mc->mc_db->md_depth++;
6665 *mc->mc_dbflag |= DB_DIRTY;
6666 if ((mc->mc_db->md_flags & (MDB_DUPSORT|MDB_DUPFIXED))
6667 == MDB_DUPFIXED)
6668 np->mp_flags |= P_LEAF2;
6669 mc->mc_flags |= C_INITIALIZED;
6670 } else {
6671 /* make sure all cursor pages are writable */
6672 rc2 = mdb_cursor_touch(mc);
6673 if (rc2)
6674 return rc2;
6675 }
6676
6677 insert_key = insert_data = rc;
6678 if (insert_key) {
6679 /* The key does not exist */
6680 DPRINTF(("inserting key at index %i", mc->mc_ki[mc->mc_top]));
6681 if ((mc->mc_db->md_flags & MDB_DUPSORT) &&
6682 LEAFSIZE(key, data) > env->me_nodemax)
6683 {
6684 /* Too big for a node, insert in sub-DB. Set up an empty
6685 * "old sub-page" for prep_subDB to expand to a full page.
6686 */
6687 fp_flags = P_LEAF|P_DIRTY;
6688 fp = env->me_pbuf;
6689 fp->mp_pad = data->mv_size; /* used if MDB_DUPFIXED */
6690 fp->mp_lower = fp->mp_upper = (PAGEHDRSZ-PAGEBASE);
6691 olddata.mv_size = PAGEHDRSZ;
6692 goto prep_subDB;
6693 }
6694 } else {
6695 /* there's only a key anyway, so this is a no-op */
6696 if (IS_LEAF2(mc->mc_pg[mc->mc_top])) {
6697 char *ptr;
6698 unsigned int ksize = mc->mc_db->md_pad;
6699 if (key->mv_size != ksize)
6700 return MDB_BAD_VALSIZE;
6701 ptr = LEAF2KEY(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top], ksize);
6702 memcpy(ptr, key->mv_data, ksize);
6703 fix_parent:
6704 /* if overwriting slot 0 of leaf, need to
6705 * update branch key if there is a parent page
6706 */
6707 if (mc->mc_top && !mc->mc_ki[mc->mc_top]) {
6708 unsigned short dtop = 1;
6709 mc->mc_top--;
6710 /* slot 0 is always an empty key, find real slot */
6711 while (mc->mc_top && !mc->mc_ki[mc->mc_top]) {
6712 mc->mc_top--;
6713 dtop++;
6714 }
6715 if (mc->mc_ki[mc->mc_top])
6716 rc2 = mdb_update_key(mc, key);
6717 else
6718 rc2 = MDB_SUCCESS;
6719 mc->mc_top += dtop;
6720 if (rc2)
6721 return rc2;
6722 }
6723 return MDB_SUCCESS;
6724 }
6725
6726 more:
6727 leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
6728 olddata.mv_size = NODEDSZ(leaf);
6729 olddata.mv_data = NODEDATA(leaf);
6730
6731 /* DB has dups? */
6732 if (F_ISSET(mc->mc_db->md_flags, MDB_DUPSORT)) {
6733 /* Prepare (sub-)page/sub-DB to accept the new item,
6734 * if needed. fp: old sub-page or a header faking
6735 * it. mp: new (sub-)page. offset: growth in page
6736 * size. xdata: node data with new page or DB.
6737 */
6738 unsigned i, offset = 0;
6739 mp = fp = xdata.mv_data = env->me_pbuf;
6740 mp->mp_pgno = mc->mc_pg[mc->mc_top]->mp_pgno;
6741
6742 /* Was a single item before, must convert now */
6743 if (!F_ISSET(leaf->mn_flags, F_DUPDATA)) {
6744 MDB_cmp_func *dcmp;
6745 /* Just overwrite the current item */
6746 if (flags == MDB_CURRENT)
6747 goto current;
6748 dcmp = mc->mc_dbx->md_dcmp;
6749 #if UINT_MAX < SIZE_MAX
6750 if (dcmp == mdb_cmp_int && olddata.mv_size == sizeof(size_t))
6751 dcmp = mdb_cmp_clong;
6752 #endif
6753 /* does data match? */
6754 if (!dcmp(data, &olddata)) {
6755 if (flags & (MDB_NODUPDATA|MDB_APPENDDUP))
6756 return MDB_KEYEXIST;
6757 /* overwrite it */
6758 goto current;
6759 }
6760
6761 /* Back up original data item */
6762 dkey.mv_size = olddata.mv_size;
6763 dkey.mv_data = memcpy(fp+1, olddata.mv_data, olddata.mv_size);
6764
6765 /* Make sub-page header for the dup items, with dummy body */
6766 fp->mp_flags = P_LEAF|P_DIRTY|P_SUBP;
6767 fp->mp_lower = (PAGEHDRSZ-PAGEBASE);
6768 xdata.mv_size = PAGEHDRSZ + dkey.mv_size + data->mv_size;
6769 if (mc->mc_db->md_flags & MDB_DUPFIXED) {
6770 fp->mp_flags |= P_LEAF2;
6771 fp->mp_pad = data->mv_size;
6772 xdata.mv_size += 2 * data->mv_size; /* leave space for 2 more */
6773 } else {
6774 xdata.mv_size += 2 * (sizeof(indx_t) + NODESIZE) +
6775 (dkey.mv_size & 1) + (data->mv_size & 1);
6776 }
6777 fp->mp_upper = xdata.mv_size - PAGEBASE;
6778 olddata.mv_size = xdata.mv_size; /* pretend olddata is fp */
6779 } else if (leaf->mn_flags & F_SUBDATA) {
6780 /* Data is on sub-DB, just store it */
6781 flags |= F_DUPDATA|F_SUBDATA;
6782 goto put_sub;
6783 } else {
6784 /* Data is on sub-page */
6785 fp = olddata.mv_data;
6786 switch (flags) {
6787 default:
6788 if (!(mc->mc_db->md_flags & MDB_DUPFIXED)) {
6789 offset = EVEN(NODESIZE + sizeof(indx_t) +
6790 data->mv_size);
6791 break;
6792 }
6793 offset = fp->mp_pad;
6794 if (SIZELEFT(fp) < offset) {
6795 offset *= 4; /* space for 4 more */
6796 break;
6797 }
6798 /* FALLTHRU */ /* Big enough MDB_DUPFIXED sub-page */
6799 case MDB_CURRENT:
6800 fp->mp_flags |= P_DIRTY;
6801 COPY_PGNO(fp->mp_pgno, mp->mp_pgno);
6802 mc->mc_xcursor->mx_cursor.mc_pg[0] = fp;
6803 flags |= F_DUPDATA;
6804 goto put_sub;
6805 }
6806 xdata.mv_size = olddata.mv_size + offset;
6807 }
6808
6809 fp_flags = fp->mp_flags;
6810 if (NODESIZE + NODEKSZ(leaf) + xdata.mv_size > env->me_nodemax) {
6811 /* Too big for a sub-page, convert to sub-DB */
6812 fp_flags &= ~P_SUBP;
6813 prep_subDB:
6814 if (mc->mc_db->md_flags & MDB_DUPFIXED) {
6815 fp_flags |= P_LEAF2;
6816 dummy.md_pad = fp->mp_pad;
6817 dummy.md_flags = MDB_DUPFIXED;
6818 if (mc->mc_db->md_flags & MDB_INTEGERDUP)
6819 dummy.md_flags |= MDB_INTEGERKEY;
6820 } else {
6821 dummy.md_pad = 0;
6822 dummy.md_flags = 0;
6823 }
6824 dummy.md_depth = 1;
6825 dummy.md_branch_pages = 0;
6826 dummy.md_leaf_pages = 1;
6827 dummy.md_overflow_pages = 0;
6828 dummy.md_entries = NUMKEYS(fp);
6829 xdata.mv_size = sizeof(MDB_db);
6830 xdata.mv_data = &dummy;
6831 if ((rc = mdb_page_alloc(mc, 1, &mp)))
6832 return rc;
6833 offset = env->me_psize - olddata.mv_size;
6834 flags |= F_DUPDATA|F_SUBDATA;
6835 dummy.md_root = mp->mp_pgno;
6836 sub_root = mp;
6837 }
6838 if (mp != fp) {
6839 mp->mp_flags = fp_flags | P_DIRTY;
6840 mp->mp_pad = fp->mp_pad;
6841 mp->mp_lower = fp->mp_lower;
6842 mp->mp_upper = fp->mp_upper + offset;
6843 if (fp_flags & P_LEAF2) {
6844 memcpy(METADATA(mp), METADATA(fp), NUMKEYS(fp) * fp->mp_pad);
6845 } else {
6846 memcpy((char *)mp + mp->mp_upper + PAGEBASE, (char *)fp + fp->mp_upper + PAGEBASE,
6847 olddata.mv_size - fp->mp_upper - PAGEBASE);
6848 memcpy((char *)(&mp->mp_ptrs), (char *)(&fp->mp_ptrs), NUMKEYS(fp) * sizeof(mp->mp_ptrs[0]));
6849 for (i=0; i<NUMKEYS(fp); i++)
6850 mp->mp_ptrs[i] += offset;
6851 }
6852 }
6853
6854 rdata = &xdata;
6855 flags |= F_DUPDATA;
6856 do_sub = 1;
6857 if (!insert_key)
6858 mdb_node_del(mc, 0);
6859 goto new_sub;
6860 }
6861 current:
6862 /* LMDB passes F_SUBDATA in 'flags' to write a DB record */
6863 if ((leaf->mn_flags ^ flags) & F_SUBDATA)
6864 return MDB_INCOMPATIBLE;
6865 /* overflow page overwrites need special handling */
6866 if (F_ISSET(leaf->mn_flags, F_BIGDATA)) {
6867 MDB_page *omp;
6868 pgno_t pg;
6869 int level, ovpages, dpages = OVPAGES(data->mv_size, env->me_psize);
6870
6871 memcpy(&pg, olddata.mv_data, sizeof(pg));
6872 if ((rc2 = mdb_page_get(mc, pg, &omp, &level)) != 0)
6873 return rc2;
6874 ovpages = omp->mp_pages;
6875
6876 /* Is the ov page large enough? */
6877 if (ovpages >= dpages) {
6878 if (!(omp->mp_flags & P_DIRTY) &&
6879 (level || (env->me_flags & MDB_WRITEMAP)))
6880 {
6881 rc = mdb_page_unspill(mc->mc_txn, omp, &omp);
6882 if (rc)
6883 return rc;
6884 level = 0; /* dirty in this txn or clean */
6885 }
6886 /* Is it dirty? */
6887 if (omp->mp_flags & P_DIRTY) {
6888 /* yes, overwrite it. Note in this case we don't
6889 * bother to try shrinking the page if the new data
6890 * is smaller than the overflow threshold.
6891 */
6892 if (level > 1) {
6893 /* It is writable only in a parent txn */
6894 size_t sz = (size_t) env->me_psize * ovpages, off;
6895 MDB_page *np = mdb_page_malloc(mc->mc_txn, ovpages);
6896 MDB_ID2 id2;
6897 if (!np)
6898 return ENOMEM;
6899 id2.mid = pg;
6900 id2.mptr = np;
6901 /* Note - this page is already counted in parent's dirty_room */
6902 rc2 = mdb_mid2l_insert(mc->mc_txn->mt_u.dirty_list, &id2);
6903 mdb_cassert(mc, rc2 == 0);
6904 /* Currently we make the page look as with put() in the
6905 * parent txn, in case the user peeks at MDB_RESERVEd
6906 * or unused parts. Some users treat ovpages specially.
6907 */
6908 if (!(flags & MDB_RESERVE)) {
6909 /* Skip the part where LMDB will put *data.
6910 * Copy end of page, adjusting alignment so
6911 * compiler may copy words instead of bytes.
6912 */
6913 off = (PAGEHDRSZ + data->mv_size) & -sizeof(size_t);
6914 memcpy((size_t *)((char *)np + off),
6915 (size_t *)((char *)omp + off), sz - off);
6916 sz = PAGEHDRSZ;
6917 }
6918 memcpy(np, omp, sz); /* Copy beginning of page */
6919 omp = np;
6920 }
6921 SETDSZ(leaf, data->mv_size);
6922 if (F_ISSET(flags, MDB_RESERVE))
6923 data->mv_data = METADATA(omp);
6924 else
6925 memcpy(METADATA(omp), data->mv_data, data->mv_size);
6926 return MDB_SUCCESS;
6927 }
6928 }
6929 if ((rc2 = mdb_ovpage_free(mc, omp)) != MDB_SUCCESS)
6930 return rc2;
6931 } else if (data->mv_size == olddata.mv_size) {
6932 /* same size, just replace it. Note that we could
6933 * also reuse this node if the new data is smaller,
6934 * but instead we opt to shrink the node in that case.
6935 */
6936 if (F_ISSET(flags, MDB_RESERVE))
6937 data->mv_data = olddata.mv_data;
6938 else if (!(mc->mc_flags & C_SUB))
6939 memcpy(olddata.mv_data, data->mv_data, data->mv_size);
6940 else {
6941 memcpy(NODEKEY(leaf), key->mv_data, key->mv_size);
6942 goto fix_parent;
6943 }
6944 return MDB_SUCCESS;
6945 }
6946 mdb_node_del(mc, 0);
6947 }
6948
6949 rdata = data;
6950
6951 new_sub:
6952 nflags = flags & NODE_ADD_FLAGS;
6953 nsize = IS_LEAF2(mc->mc_pg[mc->mc_top]) ? key->mv_size : mdb_leaf_size(env, key, rdata);
6954 if (SIZELEFT(mc->mc_pg[mc->mc_top]) < nsize) {
6955 if (( flags & (F_DUPDATA|F_SUBDATA)) == F_DUPDATA )
6956 nflags &= ~MDB_APPEND; /* sub-page may need room to grow */
6957 if (!insert_key)
6958 nflags |= MDB_SPLIT_REPLACE;
6959 rc = mdb_page_split(mc, key, rdata, P_INVALID, nflags);
6960 } else {
6961 /* There is room already in this leaf page. */
6962 rc = mdb_node_add(mc, mc->mc_ki[mc->mc_top], key, rdata, 0, nflags);
6963 if (rc == 0) {
6964 /* Adjust other cursors pointing to mp */
6965 MDB_cursor *m2, *m3;
6966 MDB_dbi dbi = mc->mc_dbi;
6967 unsigned i = mc->mc_top;
6968 MDB_page *mp = mc->mc_pg[i];
6969
6970 for (m2 = mc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
6971 if (mc->mc_flags & C_SUB)
6972 m3 = &m2->mc_xcursor->mx_cursor;
6973 else
6974 m3 = m2;
6975 if (m3 == mc || m3->mc_snum < mc->mc_snum || m3->mc_pg[i] != mp) continue;
6976 if (m3->mc_ki[i] >= mc->mc_ki[i] && insert_key) {
6977 m3->mc_ki[i]++;
6978 }
6979 XCURSOR_REFRESH(m3, i, mp);
6980 }
6981 }
6982 }
6983
6984 if (rc == MDB_SUCCESS) {
6985 /* Now store the actual data in the child DB. Note that we're
6986 * storing the user data in the keys field, so there are strict
6987 * size limits on dupdata. The actual data fields of the child
6988 * DB are all zero size.
6989 */
6990 if (do_sub) {
6991 int xflags, new_dupdata;
6992 size_t ecount;
6993 put_sub:
6994 xdata.mv_size = 0;
6995 xdata.mv_data = "";
6996 leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
6997 if ((flags & (MDB_CURRENT|MDB_APPENDDUP)) == MDB_CURRENT) {
6998 xflags = MDB_CURRENT|MDB_NOSPILL;
6999 } else {
7000 mdb_xcursor_init1(mc, leaf);
7001 xflags = (flags & MDB_NODUPDATA) ?
7002 MDB_NOOVERWRITE|MDB_NOSPILL : MDB_NOSPILL;
7003 }
7004 if (sub_root)
7005 mc->mc_xcursor->mx_cursor.mc_pg[0] = sub_root;
7006 new_dupdata = (int)dkey.mv_size;
7007 /* converted, write the original data first */
7008 if (dkey.mv_size) {
7009 rc = mdb_cursor_put(&mc->mc_xcursor->mx_cursor, &dkey, &xdata, xflags);
7010 if (rc)
7011 goto bad_sub;
7012 /* we've done our job */
7013 dkey.mv_size = 0;
7014 }
7015 if (!(leaf->mn_flags & F_SUBDATA) || sub_root) {
7016 /* Adjust other cursors pointing to mp */
7017 MDB_cursor *m2;
7018 MDB_xcursor *mx = mc->mc_xcursor;
7019 unsigned i = mc->mc_top;
7020 MDB_page *mp = mc->mc_pg[i];
7021
7022 for (m2 = mc->mc_txn->mt_cursors[mc->mc_dbi]; m2; m2=m2->mc_next) {
7023 if (m2 == mc || m2->mc_snum < mc->mc_snum) continue;
7024 if (!(m2->mc_flags & C_INITIALIZED)) continue;
7025 if (m2->mc_pg[i] == mp) {
7026 if (m2->mc_ki[i] == mc->mc_ki[i]) {
7027 mdb_xcursor_init2(m2, mx, new_dupdata);
7028 } else if (!insert_key) {
7029 XCURSOR_REFRESH(m2, i, mp);
7030 }
7031 }
7032 }
7033 }
7034 ecount = mc->mc_xcursor->mx_db.md_entries;
7035 if (flags & MDB_APPENDDUP)
7036 xflags |= MDB_APPEND;
7037 rc = mdb_cursor_put(&mc->mc_xcursor->mx_cursor, data, &xdata, xflags);
7038 if (flags & F_SUBDATA) {
7039 void *db = NODEDATA(leaf);
7040 memcpy(db, &mc->mc_xcursor->mx_db, sizeof(MDB_db));
7041 }
7042 insert_data = mc->mc_xcursor->mx_db.md_entries - ecount;
7043 }
7044 /* Increment count unless we just replaced an existing item. */
7045 if (insert_data)
7046 mc->mc_db->md_entries++;
7047 if (insert_key) {
7048 /* Invalidate txn if we created an empty sub-DB */
7049 if (rc)
7050 goto bad_sub;
7051 /* If we succeeded and the key didn't exist before,
7052 * make sure the cursor is marked valid.
7053 */
7054 mc->mc_flags |= C_INITIALIZED;
7055 }
7056 if (flags & MDB_MULTIPLE) {
7057 if (!rc) {
7058 mcount++;
7059 /* let caller know how many succeeded, if any */
7060 data[1].mv_size = mcount;
7061 if (mcount < dcount) {
7062 data[0].mv_data = (char *)data[0].mv_data + data[0].mv_size;
7063 insert_key = insert_data = 0;
7064 goto more;
7065 }
7066 }
7067 }
7068 return rc;
7069 bad_sub:
7070 if (rc == MDB_KEYEXIST) /* should not happen, we deleted that item */
7071 rc = MDB_CORRUPTED;
7072 }
7073 mc->mc_txn->mt_flags |= MDB_TXN_ERROR;
7074 return rc;
7075 }
7076
7077 int
mdb_cursor_del(MDB_cursor * mc,unsigned int flags)7078 mdb_cursor_del(MDB_cursor *mc, unsigned int flags)
7079 {
7080 MDB_node *leaf;
7081 MDB_page *mp;
7082 int rc;
7083
7084 if (mc->mc_txn->mt_flags & (MDB_TXN_RDONLY|MDB_TXN_BLOCKED))
7085 return (mc->mc_txn->mt_flags & MDB_TXN_RDONLY) ? EACCES : MDB_BAD_TXN;
7086
7087 if (!(mc->mc_flags & C_INITIALIZED))
7088 return EINVAL;
7089
7090 if (mc->mc_ki[mc->mc_top] >= NUMKEYS(mc->mc_pg[mc->mc_top]))
7091 return MDB_NOTFOUND;
7092
7093 if (!(flags & MDB_NOSPILL) && (rc = mdb_page_spill(mc, NULL, NULL)))
7094 return rc;
7095
7096 rc = mdb_cursor_touch(mc);
7097 if (rc)
7098 return rc;
7099
7100 mp = mc->mc_pg[mc->mc_top];
7101 if (!IS_LEAF(mp))
7102 return MDB_CORRUPTED;
7103 if (IS_LEAF2(mp))
7104 goto del_key;
7105 leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
7106
7107 if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
7108 if (flags & MDB_NODUPDATA) {
7109 /* mdb_cursor_del0() will subtract the final entry */
7110 mc->mc_db->md_entries -= mc->mc_xcursor->mx_db.md_entries - 1;
7111 mc->mc_xcursor->mx_cursor.mc_flags &= ~C_INITIALIZED;
7112 } else {
7113 if (!F_ISSET(leaf->mn_flags, F_SUBDATA)) {
7114 mc->mc_xcursor->mx_cursor.mc_pg[0] = NODEDATA(leaf);
7115 }
7116 rc = mdb_cursor_del(&mc->mc_xcursor->mx_cursor, MDB_NOSPILL);
7117 if (rc)
7118 return rc;
7119 /* If sub-DB still has entries, we're done */
7120 if (mc->mc_xcursor->mx_db.md_entries) {
7121 if (leaf->mn_flags & F_SUBDATA) {
7122 /* update subDB info */
7123 void *db = NODEDATA(leaf);
7124 memcpy(db, &mc->mc_xcursor->mx_db, sizeof(MDB_db));
7125 } else {
7126 MDB_cursor *m2;
7127 /* shrink fake page */
7128 mdb_node_shrink(mp, mc->mc_ki[mc->mc_top]);
7129 leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
7130 mc->mc_xcursor->mx_cursor.mc_pg[0] = NODEDATA(leaf);
7131 /* fix other sub-DB cursors pointed at fake pages on this page */
7132 for (m2 = mc->mc_txn->mt_cursors[mc->mc_dbi]; m2; m2=m2->mc_next) {
7133 if (m2 == mc || m2->mc_snum < mc->mc_snum) continue;
7134 if (!(m2->mc_flags & C_INITIALIZED)) continue;
7135 if (m2->mc_pg[mc->mc_top] == mp) {
7136 XCURSOR_REFRESH(m2, mc->mc_top, mp);
7137 }
7138 }
7139 }
7140 mc->mc_db->md_entries--;
7141 return rc;
7142 } else {
7143 mc->mc_xcursor->mx_cursor.mc_flags &= ~C_INITIALIZED;
7144 }
7145 /* otherwise fall thru and delete the sub-DB */
7146 }
7147
7148 if (leaf->mn_flags & F_SUBDATA) {
7149 /* add all the child DB's pages to the free list */
7150 rc = mdb_drop0(&mc->mc_xcursor->mx_cursor, 0);
7151 if (rc)
7152 goto fail;
7153 }
7154 }
7155 /* LMDB passes F_SUBDATA in 'flags' to delete a DB record */
7156 else if ((leaf->mn_flags ^ flags) & F_SUBDATA) {
7157 rc = MDB_INCOMPATIBLE;
7158 goto fail;
7159 }
7160
7161 /* add overflow pages to free list */
7162 if (F_ISSET(leaf->mn_flags, F_BIGDATA)) {
7163 MDB_page *omp;
7164 pgno_t pg;
7165
7166 memcpy(&pg, NODEDATA(leaf), sizeof(pg));
7167 if ((rc = mdb_page_get(mc, pg, &omp, NULL)) ||
7168 (rc = mdb_ovpage_free(mc, omp)))
7169 goto fail;
7170 }
7171
7172 del_key:
7173 return mdb_cursor_del0(mc);
7174
7175 fail:
7176 mc->mc_txn->mt_flags |= MDB_TXN_ERROR;
7177 return rc;
7178 }
7179
7180 /** Allocate and initialize new pages for a database.
7181 * Set #MDB_TXN_ERROR on failure.
7182 * @param[in] mc a cursor on the database being added to.
7183 * @param[in] flags flags defining what type of page is being allocated.
7184 * @param[in] num the number of pages to allocate. This is usually 1,
7185 * unless allocating overflow pages for a large record.
7186 * @param[out] mp Address of a page, or NULL on failure.
7187 * @return 0 on success, non-zero on failure.
7188 */
7189 static int
mdb_page_new(MDB_cursor * mc,uint32_t flags,int num,MDB_page ** mp)7190 mdb_page_new(MDB_cursor *mc, uint32_t flags, int num, MDB_page **mp)
7191 {
7192 MDB_page *np;
7193 int rc;
7194
7195 if ((rc = mdb_page_alloc(mc, num, &np)))
7196 return rc;
7197 DPRINTF(("allocated new mpage %"Z"u, page size %u",
7198 np->mp_pgno, mc->mc_txn->mt_env->me_psize));
7199 np->mp_flags = flags | P_DIRTY;
7200 np->mp_lower = (PAGEHDRSZ-PAGEBASE);
7201 np->mp_upper = mc->mc_txn->mt_env->me_psize - PAGEBASE;
7202
7203 if (IS_BRANCH(np))
7204 mc->mc_db->md_branch_pages++;
7205 else if (IS_LEAF(np))
7206 mc->mc_db->md_leaf_pages++;
7207 else if (IS_OVERFLOW(np)) {
7208 mc->mc_db->md_overflow_pages += num;
7209 np->mp_pages = num;
7210 }
7211 *mp = np;
7212
7213 return 0;
7214 }
7215
7216 /** Calculate the size of a leaf node.
7217 * The size depends on the environment's page size; if a data item
7218 * is too large it will be put onto an overflow page and the node
7219 * size will only include the key and not the data. Sizes are always
7220 * rounded up to an even number of bytes, to guarantee 2-byte alignment
7221 * of the #MDB_node headers.
7222 * @param[in] env The environment handle.
7223 * @param[in] key The key for the node.
7224 * @param[in] data The data for the node.
7225 * @return The number of bytes needed to store the node.
7226 */
7227 static size_t
mdb_leaf_size(MDB_env * env,MDB_val * key,MDB_val * data)7228 mdb_leaf_size(MDB_env *env, MDB_val *key, MDB_val *data)
7229 {
7230 size_t sz;
7231
7232 sz = LEAFSIZE(key, data);
7233 if (sz > env->me_nodemax) {
7234 /* put on overflow page */
7235 sz -= data->mv_size - sizeof(pgno_t);
7236 }
7237
7238 return EVEN(sz + sizeof(indx_t));
7239 }
7240
7241 /** Calculate the size of a branch node.
7242 * The size should depend on the environment's page size but since
7243 * we currently don't support spilling large keys onto overflow
7244 * pages, it's simply the size of the #MDB_node header plus the
7245 * size of the key. Sizes are always rounded up to an even number
7246 * of bytes, to guarantee 2-byte alignment of the #MDB_node headers.
7247 * @param[in] env The environment handle.
7248 * @param[in] key The key for the node.
7249 * @return The number of bytes needed to store the node.
7250 */
7251 static size_t
mdb_branch_size(MDB_env * env,MDB_val * key)7252 mdb_branch_size(MDB_env *env, MDB_val *key)
7253 {
7254 size_t sz;
7255
7256 sz = INDXSIZE(key);
7257 if (sz > env->me_nodemax) {
7258 /* put on overflow page */
7259 /* not implemented */
7260 /* sz -= key->size - sizeof(pgno_t); */
7261 }
7262
7263 return sz + sizeof(indx_t);
7264 }
7265
7266 /** Add a node to the page pointed to by the cursor.
7267 * Set #MDB_TXN_ERROR on failure.
7268 * @param[in] mc The cursor for this operation.
7269 * @param[in] indx The index on the page where the new node should be added.
7270 * @param[in] key The key for the new node.
7271 * @param[in] data The data for the new node, if any.
7272 * @param[in] pgno The page number, if adding a branch node.
7273 * @param[in] flags Flags for the node.
7274 * @return 0 on success, non-zero on failure. Possible errors are:
7275 * <ul>
7276 * <li>ENOMEM - failed to allocate overflow pages for the node.
7277 * <li>MDB_PAGE_FULL - there is insufficient room in the page. This error
7278 * should never happen since all callers already calculate the
7279 * page's free space before calling this function.
7280 * </ul>
7281 */
7282 static int
mdb_node_add(MDB_cursor * mc,indx_t indx,MDB_val * key,MDB_val * data,pgno_t pgno,unsigned int flags)7283 mdb_node_add(MDB_cursor *mc, indx_t indx,
7284 MDB_val *key, MDB_val *data, pgno_t pgno, unsigned int flags)
7285 {
7286 unsigned int i;
7287 size_t node_size = NODESIZE;
7288 ssize_t room;
7289 indx_t ofs;
7290 MDB_node *node;
7291 MDB_page *mp = mc->mc_pg[mc->mc_top];
7292 MDB_page *ofp = NULL; /* overflow page */
7293 void *ndata;
7294 DKBUF;
7295
7296 mdb_cassert(mc, mp->mp_upper >= mp->mp_lower);
7297
7298 DPRINTF(("add to %s %spage %"Z"u index %i, data size %"Z"u key size %"Z"u [%s]",
7299 IS_LEAF(mp) ? "leaf" : "branch",
7300 IS_SUBP(mp) ? "sub-" : "",
7301 mdb_dbg_pgno(mp), indx, data ? data->mv_size : 0,
7302 key ? key->mv_size : 0, key ? DKEY(key) : "null"));
7303
7304 if (IS_LEAF2(mp)) {
7305 /* Move higher keys up one slot. */
7306 int ksize = mc->mc_db->md_pad, dif;
7307 char *ptr = LEAF2KEY(mp, indx, ksize);
7308 dif = NUMKEYS(mp) - indx;
7309 if (dif > 0)
7310 memmove(ptr+ksize, ptr, dif*ksize);
7311 /* insert new key */
7312 memcpy(ptr, key->mv_data, ksize);
7313
7314 /* Just using these for counting */
7315 mp->mp_lower += sizeof(indx_t);
7316 mp->mp_upper -= ksize - sizeof(indx_t);
7317 return MDB_SUCCESS;
7318 }
7319
7320 room = (ssize_t)SIZELEFT(mp) - (ssize_t)sizeof(indx_t);
7321 if (key != NULL)
7322 node_size += key->mv_size;
7323 if (IS_LEAF(mp)) {
7324 mdb_cassert(mc, key && data);
7325 if (F_ISSET(flags, F_BIGDATA)) {
7326 /* Data already on overflow page. */
7327 node_size += sizeof(pgno_t);
7328 } else if (node_size + data->mv_size > mc->mc_txn->mt_env->me_nodemax) {
7329 int ovpages = OVPAGES(data->mv_size, mc->mc_txn->mt_env->me_psize);
7330 int rc;
7331 /* Put data on overflow page. */
7332 DPRINTF(("data size is %"Z"u, node would be %"Z"u, put data on overflow page",
7333 data->mv_size, node_size+data->mv_size));
7334 node_size = EVEN(node_size + sizeof(pgno_t));
7335 if ((ssize_t)node_size > room)
7336 goto full;
7337 if ((rc = mdb_page_new(mc, P_OVERFLOW, ovpages, &ofp)))
7338 return rc;
7339 DPRINTF(("allocated overflow page %"Z"u", ofp->mp_pgno));
7340 flags |= F_BIGDATA;
7341 goto update;
7342 } else {
7343 node_size += data->mv_size;
7344 }
7345 }
7346 node_size = EVEN(node_size);
7347 if ((ssize_t)node_size > room)
7348 goto full;
7349
7350 update:
7351 /* Move higher pointers up one slot. */
7352 for (i = NUMKEYS(mp); i > indx; i--)
7353 mp->mp_ptrs[i] = mp->mp_ptrs[i - 1];
7354
7355 /* Adjust free space offsets. */
7356 ofs = mp->mp_upper - node_size;
7357 mdb_cassert(mc, ofs >= mp->mp_lower + sizeof(indx_t));
7358 mp->mp_ptrs[indx] = ofs;
7359 mp->mp_upper = ofs;
7360 mp->mp_lower += sizeof(indx_t);
7361
7362 /* Write the node data. */
7363 node = NODEPTR(mp, indx);
7364 node->mn_ksize = (key == NULL) ? 0 : key->mv_size;
7365 node->mn_flags = flags;
7366 if (IS_LEAF(mp))
7367 SETDSZ(node,data->mv_size);
7368 else
7369 SETPGNO(node,pgno);
7370
7371 if (key)
7372 memcpy(NODEKEY(node), key->mv_data, key->mv_size);
7373
7374 if (IS_LEAF(mp)) {
7375 ndata = NODEDATA(node);
7376 if (ofp == NULL) {
7377 if (F_ISSET(flags, F_BIGDATA))
7378 memcpy(ndata, data->mv_data, sizeof(pgno_t));
7379 else if (F_ISSET(flags, MDB_RESERVE))
7380 data->mv_data = ndata;
7381 else
7382 memcpy(ndata, data->mv_data, data->mv_size);
7383 } else {
7384 memcpy(ndata, &ofp->mp_pgno, sizeof(pgno_t));
7385 ndata = METADATA(ofp);
7386 if (F_ISSET(flags, MDB_RESERVE))
7387 data->mv_data = ndata;
7388 else
7389 memcpy(ndata, data->mv_data, data->mv_size);
7390 }
7391 }
7392
7393 return MDB_SUCCESS;
7394
7395 full:
7396 DPRINTF(("not enough room in page %"Z"u, got %u ptrs",
7397 mdb_dbg_pgno(mp), NUMKEYS(mp)));
7398 DPRINTF(("upper-lower = %u - %u = %"Z"d", mp->mp_upper,mp->mp_lower,room));
7399 DPRINTF(("node size = %"Z"u", node_size));
7400 mc->mc_txn->mt_flags |= MDB_TXN_ERROR;
7401 return MDB_PAGE_FULL;
7402 }
7403
7404 /** Delete the specified node from a page.
7405 * @param[in] mc Cursor pointing to the node to delete.
7406 * @param[in] ksize The size of a node. Only used if the page is
7407 * part of a #MDB_DUPFIXED database.
7408 */
7409 static void
mdb_node_del(MDB_cursor * mc,int ksize)7410 mdb_node_del(MDB_cursor *mc, int ksize)
7411 {
7412 MDB_page *mp = mc->mc_pg[mc->mc_top];
7413 indx_t indx = mc->mc_ki[mc->mc_top];
7414 unsigned int sz;
7415 indx_t i, j, numkeys, ptr;
7416 MDB_node *node;
7417 char *base;
7418
7419 DPRINTF(("delete node %u on %s page %"Z"u", indx,
7420 IS_LEAF(mp) ? "leaf" : "branch", mdb_dbg_pgno(mp)));
7421 numkeys = NUMKEYS(mp);
7422 mdb_cassert(mc, indx < numkeys);
7423
7424 if (IS_LEAF2(mp)) {
7425 int x = numkeys - 1 - indx;
7426 base = LEAF2KEY(mp, indx, ksize);
7427 if (x)
7428 memmove(base, base + ksize, x * ksize);
7429 mp->mp_lower -= sizeof(indx_t);
7430 mp->mp_upper += ksize - sizeof(indx_t);
7431 return;
7432 }
7433
7434 node = NODEPTR(mp, indx);
7435 sz = NODESIZE + node->mn_ksize;
7436 if (IS_LEAF(mp)) {
7437 if (F_ISSET(node->mn_flags, F_BIGDATA))
7438 sz += sizeof(pgno_t);
7439 else
7440 sz += NODEDSZ(node);
7441 }
7442 sz = EVEN(sz);
7443
7444 ptr = mp->mp_ptrs[indx];
7445 for (i = j = 0; i < numkeys; i++) {
7446 if (i != indx) {
7447 mp->mp_ptrs[j] = mp->mp_ptrs[i];
7448 if (mp->mp_ptrs[i] < ptr)
7449 mp->mp_ptrs[j] += sz;
7450 j++;
7451 }
7452 }
7453
7454 base = (char *)mp + mp->mp_upper + PAGEBASE;
7455 memmove(base + sz, base, ptr - mp->mp_upper);
7456
7457 mp->mp_lower -= sizeof(indx_t);
7458 mp->mp_upper += sz;
7459 }
7460
7461 /** Compact the main page after deleting a node on a subpage.
7462 * @param[in] mp The main page to operate on.
7463 * @param[in] indx The index of the subpage on the main page.
7464 */
7465 static void
mdb_node_shrink(MDB_page * mp,indx_t indx)7466 mdb_node_shrink(MDB_page *mp, indx_t indx)
7467 {
7468 MDB_node *node;
7469 MDB_page *sp, *xp;
7470 char *base;
7471 indx_t delta, nsize, len, ptr;
7472 int i;
7473
7474 node = NODEPTR(mp, indx);
7475 sp = (MDB_page *)NODEDATA(node);
7476 delta = SIZELEFT(sp);
7477 nsize = NODEDSZ(node) - delta;
7478
7479 /* Prepare to shift upward, set len = length(subpage part to shift) */
7480 if (IS_LEAF2(sp)) {
7481 len = nsize;
7482 if (nsize & 1)
7483 return; /* do not make the node uneven-sized */
7484 } else {
7485 xp = (MDB_page *)((char *)sp + delta); /* destination subpage */
7486 for (i = NUMKEYS(sp); --i >= 0; )
7487 xp->mp_ptrs[i] = sp->mp_ptrs[i] - delta;
7488 len = PAGEHDRSZ;
7489 }
7490 sp->mp_upper = sp->mp_lower;
7491 COPY_PGNO(sp->mp_pgno, mp->mp_pgno);
7492 SETDSZ(node, nsize);
7493
7494 /* Shift <lower nodes...initial part of subpage> upward */
7495 base = (char *)mp + mp->mp_upper + PAGEBASE;
7496 memmove(base + delta, base, (char *)sp + len - base);
7497
7498 ptr = mp->mp_ptrs[indx];
7499 for (i = NUMKEYS(mp); --i >= 0; ) {
7500 if (mp->mp_ptrs[i] <= ptr)
7501 mp->mp_ptrs[i] += delta;
7502 }
7503 mp->mp_upper += delta;
7504 }
7505
7506 /** Initial setup of a sorted-dups cursor.
7507 * Sorted duplicates are implemented as a sub-database for the given key.
7508 * The duplicate data items are actually keys of the sub-database.
7509 * Operations on the duplicate data items are performed using a sub-cursor
7510 * initialized when the sub-database is first accessed. This function does
7511 * the preliminary setup of the sub-cursor, filling in the fields that
7512 * depend only on the parent DB.
7513 * @param[in] mc The main cursor whose sorted-dups cursor is to be initialized.
7514 */
7515 static void
mdb_xcursor_init0(MDB_cursor * mc)7516 mdb_xcursor_init0(MDB_cursor *mc)
7517 {
7518 MDB_xcursor *mx = mc->mc_xcursor;
7519
7520 mx->mx_cursor.mc_xcursor = NULL;
7521 mx->mx_cursor.mc_txn = mc->mc_txn;
7522 mx->mx_cursor.mc_db = &mx->mx_db;
7523 mx->mx_cursor.mc_dbx = &mx->mx_dbx;
7524 mx->mx_cursor.mc_dbi = mc->mc_dbi;
7525 mx->mx_cursor.mc_dbflag = &mx->mx_dbflag;
7526 mx->mx_cursor.mc_snum = 0;
7527 mx->mx_cursor.mc_top = 0;
7528 mx->mx_cursor.mc_flags = C_SUB;
7529 mx->mx_dbx.md_name.mv_size = 0;
7530 mx->mx_dbx.md_name.mv_data = NULL;
7531 mx->mx_dbx.md_cmp = mc->mc_dbx->md_dcmp;
7532 mx->mx_dbx.md_dcmp = NULL;
7533 mx->mx_dbx.md_rel = mc->mc_dbx->md_rel;
7534 }
7535
7536 /** Final setup of a sorted-dups cursor.
7537 * Sets up the fields that depend on the data from the main cursor.
7538 * @param[in] mc The main cursor whose sorted-dups cursor is to be initialized.
7539 * @param[in] node The data containing the #MDB_db record for the
7540 * sorted-dup database.
7541 */
7542 static void
mdb_xcursor_init1(MDB_cursor * mc,MDB_node * node)7543 mdb_xcursor_init1(MDB_cursor *mc, MDB_node *node)
7544 {
7545 MDB_xcursor *mx = mc->mc_xcursor;
7546
7547 if (node->mn_flags & F_SUBDATA) {
7548 memcpy(&mx->mx_db, NODEDATA(node), sizeof(MDB_db));
7549 mx->mx_cursor.mc_pg[0] = 0;
7550 mx->mx_cursor.mc_snum = 0;
7551 mx->mx_cursor.mc_top = 0;
7552 mx->mx_cursor.mc_flags = C_SUB;
7553 } else {
7554 MDB_page *fp = NODEDATA(node);
7555 mx->mx_db.md_pad = 0;
7556 mx->mx_db.md_flags = 0;
7557 mx->mx_db.md_depth = 1;
7558 mx->mx_db.md_branch_pages = 0;
7559 mx->mx_db.md_leaf_pages = 1;
7560 mx->mx_db.md_overflow_pages = 0;
7561 mx->mx_db.md_entries = NUMKEYS(fp);
7562 COPY_PGNO(mx->mx_db.md_root, fp->mp_pgno);
7563 mx->mx_cursor.mc_snum = 1;
7564 mx->mx_cursor.mc_top = 0;
7565 mx->mx_cursor.mc_flags = C_INITIALIZED|C_SUB;
7566 mx->mx_cursor.mc_pg[0] = fp;
7567 mx->mx_cursor.mc_ki[0] = 0;
7568 if (mc->mc_db->md_flags & MDB_DUPFIXED) {
7569 mx->mx_db.md_flags = MDB_DUPFIXED;
7570 mx->mx_db.md_pad = fp->mp_pad;
7571 if (mc->mc_db->md_flags & MDB_INTEGERDUP)
7572 mx->mx_db.md_flags |= MDB_INTEGERKEY;
7573 }
7574 }
7575 DPRINTF(("Sub-db -%u root page %"Z"u", mx->mx_cursor.mc_dbi,
7576 mx->mx_db.md_root));
7577 mx->mx_dbflag = DB_VALID|DB_USRVALID|DB_DUPDATA;
7578 #if UINT_MAX < SIZE_MAX
7579 if (mx->mx_dbx.md_cmp == mdb_cmp_int && mx->mx_db.md_pad == sizeof(size_t))
7580 mx->mx_dbx.md_cmp = mdb_cmp_clong;
7581 #endif
7582 }
7583
7584
7585 /** Fixup a sorted-dups cursor due to underlying update.
7586 * Sets up some fields that depend on the data from the main cursor.
7587 * Almost the same as init1, but skips initialization steps if the
7588 * xcursor had already been used.
7589 * @param[in] mc The main cursor whose sorted-dups cursor is to be fixed up.
7590 * @param[in] src_mx The xcursor of an up-to-date cursor.
7591 * @param[in] new_dupdata True if converting from a non-#F_DUPDATA item.
7592 */
7593 static void
mdb_xcursor_init2(MDB_cursor * mc,MDB_xcursor * src_mx,int new_dupdata)7594 mdb_xcursor_init2(MDB_cursor *mc, MDB_xcursor *src_mx, int new_dupdata)
7595 {
7596 MDB_xcursor *mx = mc->mc_xcursor;
7597
7598 if (new_dupdata) {
7599 mx->mx_cursor.mc_snum = 1;
7600 mx->mx_cursor.mc_top = 0;
7601 mx->mx_cursor.mc_flags |= C_INITIALIZED;
7602 mx->mx_cursor.mc_ki[0] = 0;
7603 mx->mx_dbflag = DB_VALID|DB_USRVALID|DB_DUPDATA;
7604 #if UINT_MAX < SIZE_MAX
7605 mx->mx_dbx.md_cmp = src_mx->mx_dbx.md_cmp;
7606 #endif
7607 } else if (!(mx->mx_cursor.mc_flags & C_INITIALIZED)) {
7608 return;
7609 }
7610 mx->mx_db = src_mx->mx_db;
7611 mx->mx_cursor.mc_pg[0] = src_mx->mx_cursor.mc_pg[0];
7612 DPRINTF(("Sub-db -%u root page %"Z"u", mx->mx_cursor.mc_dbi,
7613 mx->mx_db.md_root));
7614 }
7615
7616 /** Initialize a cursor for a given transaction and database. */
7617 static void
mdb_cursor_init(MDB_cursor * mc,MDB_txn * txn,MDB_dbi dbi,MDB_xcursor * mx)7618 mdb_cursor_init(MDB_cursor *mc, MDB_txn *txn, MDB_dbi dbi, MDB_xcursor *mx)
7619 {
7620 mc->mc_next = NULL;
7621 mc->mc_backup = NULL;
7622 mc->mc_dbi = dbi;
7623 mc->mc_txn = txn;
7624 mc->mc_db = &txn->mt_dbs[dbi];
7625 mc->mc_dbx = &txn->mt_dbxs[dbi];
7626 mc->mc_dbflag = &txn->mt_dbflags[dbi];
7627 mc->mc_snum = 0;
7628 mc->mc_top = 0;
7629 mc->mc_pg[0] = 0;
7630 mc->mc_ki[0] = 0;
7631 mc->mc_flags = 0;
7632 if (txn->mt_dbs[dbi].md_flags & MDB_DUPSORT) {
7633 mdb_tassert(txn, mx != NULL);
7634 mc->mc_xcursor = mx;
7635 mdb_xcursor_init0(mc);
7636 } else {
7637 mc->mc_xcursor = NULL;
7638 }
7639 if (*mc->mc_dbflag & DB_STALE) {
7640 mdb_page_search(mc, NULL, MDB_PS_ROOTONLY);
7641 }
7642 }
7643
7644 int
mdb_cursor_open(MDB_txn * txn,MDB_dbi dbi,MDB_cursor ** ret)7645 mdb_cursor_open(MDB_txn *txn, MDB_dbi dbi, MDB_cursor **ret)
7646 {
7647 MDB_cursor *mc;
7648 size_t size = sizeof(MDB_cursor);
7649
7650 if (!ret || !TXN_DBI_EXIST(txn, dbi, DB_VALID))
7651 return EINVAL;
7652
7653 if (txn->mt_flags & MDB_TXN_BLOCKED)
7654 return MDB_BAD_TXN;
7655
7656 if (dbi == FREE_DBI && !F_ISSET(txn->mt_flags, MDB_TXN_RDONLY))
7657 return EINVAL;
7658
7659 if (txn->mt_dbs[dbi].md_flags & MDB_DUPSORT)
7660 size += sizeof(MDB_xcursor);
7661
7662 if ((mc = malloc(size)) != NULL) {
7663 mdb_cursor_init(mc, txn, dbi, (MDB_xcursor *)(mc + 1));
7664 if (txn->mt_cursors) {
7665 mc->mc_next = txn->mt_cursors[dbi];
7666 txn->mt_cursors[dbi] = mc;
7667 mc->mc_flags |= C_UNTRACK;
7668 }
7669 } else {
7670 return ENOMEM;
7671 }
7672
7673 *ret = mc;
7674
7675 return MDB_SUCCESS;
7676 }
7677
7678 int
mdb_cursor_renew(MDB_txn * txn,MDB_cursor * mc)7679 mdb_cursor_renew(MDB_txn *txn, MDB_cursor *mc)
7680 {
7681 if (!mc || !TXN_DBI_EXIST(txn, mc->mc_dbi, DB_VALID))
7682 return EINVAL;
7683
7684 if ((mc->mc_flags & C_UNTRACK) || txn->mt_cursors)
7685 return EINVAL;
7686
7687 if (txn->mt_flags & MDB_TXN_BLOCKED)
7688 return MDB_BAD_TXN;
7689
7690 mdb_cursor_init(mc, txn, mc->mc_dbi, mc->mc_xcursor);
7691 return MDB_SUCCESS;
7692 }
7693
7694 /* Return the count of duplicate data items for the current key */
7695 int
mdb_cursor_count(MDB_cursor * mc,size_t * countp)7696 mdb_cursor_count(MDB_cursor *mc, size_t *countp)
7697 {
7698 MDB_node *leaf;
7699
7700 if (mc == NULL || countp == NULL)
7701 return EINVAL;
7702
7703 if (mc->mc_xcursor == NULL)
7704 return MDB_INCOMPATIBLE;
7705
7706 if (mc->mc_txn->mt_flags & MDB_TXN_BLOCKED)
7707 return MDB_BAD_TXN;
7708
7709 if (!(mc->mc_flags & C_INITIALIZED))
7710 return EINVAL;
7711
7712 if (!mc->mc_snum)
7713 return MDB_NOTFOUND;
7714
7715 if (mc->mc_flags & C_EOF) {
7716 if (mc->mc_ki[mc->mc_top] >= NUMKEYS(mc->mc_pg[mc->mc_top]))
7717 return MDB_NOTFOUND;
7718 mc->mc_flags ^= C_EOF;
7719 }
7720
7721 leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
7722 if (!F_ISSET(leaf->mn_flags, F_DUPDATA)) {
7723 *countp = 1;
7724 } else {
7725 if (!(mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED))
7726 return EINVAL;
7727
7728 *countp = mc->mc_xcursor->mx_db.md_entries;
7729 }
7730 return MDB_SUCCESS;
7731 }
7732
7733 void
mdb_cursor_close(MDB_cursor * mc)7734 mdb_cursor_close(MDB_cursor *mc)
7735 {
7736 if (mc && !mc->mc_backup) {
7737 /* remove from txn, if tracked */
7738 if ((mc->mc_flags & C_UNTRACK) && mc->mc_txn->mt_cursors) {
7739 MDB_cursor **prev = &mc->mc_txn->mt_cursors[mc->mc_dbi];
7740 while (*prev && *prev != mc) prev = &(*prev)->mc_next;
7741 if (*prev == mc)
7742 *prev = mc->mc_next;
7743 }
7744 free(mc);
7745 }
7746 }
7747
7748 MDB_txn *
mdb_cursor_txn(MDB_cursor * mc)7749 mdb_cursor_txn(MDB_cursor *mc)
7750 {
7751 if (!mc) return NULL;
7752 return mc->mc_txn;
7753 }
7754
7755 MDB_dbi
mdb_cursor_dbi(MDB_cursor * mc)7756 mdb_cursor_dbi(MDB_cursor *mc)
7757 {
7758 return mc->mc_dbi;
7759 }
7760
7761 /** Replace the key for a branch node with a new key.
7762 * Set #MDB_TXN_ERROR on failure.
7763 * @param[in] mc Cursor pointing to the node to operate on.
7764 * @param[in] key The new key to use.
7765 * @return 0 on success, non-zero on failure.
7766 */
7767 static int
mdb_update_key(MDB_cursor * mc,MDB_val * key)7768 mdb_update_key(MDB_cursor *mc, MDB_val *key)
7769 {
7770 MDB_page *mp;
7771 MDB_node *node;
7772 char *base;
7773 size_t len;
7774 int delta, ksize, oksize;
7775 indx_t ptr, i, numkeys, indx;
7776 DKBUF;
7777
7778 indx = mc->mc_ki[mc->mc_top];
7779 mp = mc->mc_pg[mc->mc_top];
7780 node = NODEPTR(mp, indx);
7781 ptr = mp->mp_ptrs[indx];
7782 #if MDB_DEBUG
7783 {
7784 MDB_val k2;
7785 char kbuf2[DKBUF_MAXKEYSIZE*2+1];
7786 k2.mv_data = NODEKEY(node);
7787 k2.mv_size = node->mn_ksize;
7788 DPRINTF(("update key %u (ofs %u) [%s] to [%s] on page %"Z"u",
7789 indx, ptr,
7790 mdb_dkey(&k2, kbuf2),
7791 DKEY(key),
7792 mp->mp_pgno));
7793 }
7794 #endif
7795
7796 /* Sizes must be 2-byte aligned. */
7797 ksize = EVEN(key->mv_size);
7798 oksize = EVEN(node->mn_ksize);
7799 delta = ksize - oksize;
7800
7801 /* Shift node contents if EVEN(key length) changed. */
7802 if (delta) {
7803 if (delta > 0 && SIZELEFT(mp) < delta) {
7804 pgno_t pgno;
7805 /* not enough space left, do a delete and split */
7806 DPRINTF(("Not enough room, delta = %d, splitting...", delta));
7807 pgno = NODEPGNO(node);
7808 mdb_node_del(mc, 0);
7809 return mdb_page_split(mc, key, NULL, pgno, MDB_SPLIT_REPLACE);
7810 }
7811
7812 numkeys = NUMKEYS(mp);
7813 for (i = 0; i < numkeys; i++) {
7814 if (mp->mp_ptrs[i] <= ptr)
7815 mp->mp_ptrs[i] -= delta;
7816 }
7817
7818 base = (char *)mp + mp->mp_upper + PAGEBASE;
7819 len = ptr - mp->mp_upper + NODESIZE;
7820 memmove(base - delta, base, len);
7821 mp->mp_upper -= delta;
7822
7823 node = NODEPTR(mp, indx);
7824 }
7825
7826 /* But even if no shift was needed, update ksize */
7827 if (node->mn_ksize != key->mv_size)
7828 node->mn_ksize = key->mv_size;
7829
7830 if (key->mv_size)
7831 memcpy(NODEKEY(node), key->mv_data, key->mv_size);
7832
7833 return MDB_SUCCESS;
7834 }
7835
7836 static void
7837 mdb_cursor_copy(const MDB_cursor *csrc, MDB_cursor *cdst);
7838
7839 /** Perform \b act while tracking temporary cursor \b mn */
7840 #define WITH_CURSOR_TRACKING(mn, act) do { \
7841 MDB_cursor dummy, *tracked, **tp = &(mn).mc_txn->mt_cursors[mn.mc_dbi]; \
7842 if ((mn).mc_flags & C_SUB) { \
7843 dummy.mc_flags = C_INITIALIZED; \
7844 dummy.mc_xcursor = (MDB_xcursor *)&(mn); \
7845 tracked = &dummy; \
7846 } else { \
7847 tracked = &(mn); \
7848 } \
7849 tracked->mc_next = *tp; \
7850 *tp = tracked; \
7851 { act; } \
7852 *tp = tracked->mc_next; \
7853 } while (0)
7854
7855 /** Move a node from csrc to cdst.
7856 */
7857 static int
mdb_node_move(MDB_cursor * csrc,MDB_cursor * cdst,int fromleft)7858 mdb_node_move(MDB_cursor *csrc, MDB_cursor *cdst, int fromleft)
7859 {
7860 MDB_node *srcnode;
7861 MDB_val key, data;
7862 pgno_t srcpg;
7863 MDB_cursor mn;
7864 int rc;
7865 unsigned short flags;
7866
7867 DKBUF;
7868
7869 /* Mark src and dst as dirty. */
7870 if ((rc = mdb_page_touch(csrc)) ||
7871 (rc = mdb_page_touch(cdst)))
7872 return rc;
7873
7874 if (IS_LEAF2(csrc->mc_pg[csrc->mc_top])) {
7875 key.mv_size = csrc->mc_db->md_pad;
7876 key.mv_data = LEAF2KEY(csrc->mc_pg[csrc->mc_top], csrc->mc_ki[csrc->mc_top], key.mv_size);
7877 data.mv_size = 0;
7878 data.mv_data = NULL;
7879 srcpg = 0;
7880 flags = 0;
7881 } else {
7882 srcnode = NODEPTR(csrc->mc_pg[csrc->mc_top], csrc->mc_ki[csrc->mc_top]);
7883 mdb_cassert(csrc, !((size_t)srcnode & 1));
7884 srcpg = NODEPGNO(srcnode);
7885 flags = srcnode->mn_flags;
7886 if (csrc->mc_ki[csrc->mc_top] == 0 && IS_BRANCH(csrc->mc_pg[csrc->mc_top])) {
7887 unsigned int snum = csrc->mc_snum;
7888 MDB_node *s2;
7889 /* must find the lowest key below src */
7890 rc = mdb_page_search_lowest(csrc);
7891 if (rc)
7892 return rc;
7893 if (IS_LEAF2(csrc->mc_pg[csrc->mc_top])) {
7894 key.mv_size = csrc->mc_db->md_pad;
7895 key.mv_data = LEAF2KEY(csrc->mc_pg[csrc->mc_top], 0, key.mv_size);
7896 } else {
7897 s2 = NODEPTR(csrc->mc_pg[csrc->mc_top], 0);
7898 key.mv_size = NODEKSZ(s2);
7899 key.mv_data = NODEKEY(s2);
7900 }
7901 csrc->mc_snum = snum--;
7902 csrc->mc_top = snum;
7903 } else {
7904 key.mv_size = NODEKSZ(srcnode);
7905 key.mv_data = NODEKEY(srcnode);
7906 }
7907 data.mv_size = NODEDSZ(srcnode);
7908 data.mv_data = NODEDATA(srcnode);
7909 }
7910 mn.mc_xcursor = NULL;
7911 if (IS_BRANCH(cdst->mc_pg[cdst->mc_top]) && cdst->mc_ki[cdst->mc_top] == 0) {
7912 unsigned int snum = cdst->mc_snum;
7913 MDB_node *s2;
7914 MDB_val bkey;
7915 /* must find the lowest key below dst */
7916 mdb_cursor_copy(cdst, &mn);
7917 rc = mdb_page_search_lowest(&mn);
7918 if (rc)
7919 return rc;
7920 if (IS_LEAF2(mn.mc_pg[mn.mc_top])) {
7921 bkey.mv_size = mn.mc_db->md_pad;
7922 bkey.mv_data = LEAF2KEY(mn.mc_pg[mn.mc_top], 0, bkey.mv_size);
7923 } else {
7924 s2 = NODEPTR(mn.mc_pg[mn.mc_top], 0);
7925 bkey.mv_size = NODEKSZ(s2);
7926 bkey.mv_data = NODEKEY(s2);
7927 }
7928 mn.mc_snum = snum--;
7929 mn.mc_top = snum;
7930 mn.mc_ki[snum] = 0;
7931 rc = mdb_update_key(&mn, &bkey);
7932 if (rc)
7933 return rc;
7934 }
7935
7936 DPRINTF(("moving %s node %u [%s] on page %"Z"u to node %u on page %"Z"u",
7937 IS_LEAF(csrc->mc_pg[csrc->mc_top]) ? "leaf" : "branch",
7938 csrc->mc_ki[csrc->mc_top],
7939 DKEY(&key),
7940 csrc->mc_pg[csrc->mc_top]->mp_pgno,
7941 cdst->mc_ki[cdst->mc_top], cdst->mc_pg[cdst->mc_top]->mp_pgno));
7942
7943 /* Add the node to the destination page.
7944 */
7945 rc = mdb_node_add(cdst, cdst->mc_ki[cdst->mc_top], &key, &data, srcpg, flags);
7946 if (rc != MDB_SUCCESS)
7947 return rc;
7948
7949 /* Delete the node from the source page.
7950 */
7951 mdb_node_del(csrc, key.mv_size);
7952
7953 {
7954 /* Adjust other cursors pointing to mp */
7955 MDB_cursor *m2, *m3;
7956 MDB_dbi dbi = csrc->mc_dbi;
7957 MDB_page *mpd, *mps;
7958
7959 mps = csrc->mc_pg[csrc->mc_top];
7960 /* If we're adding on the left, bump others up */
7961 if (fromleft) {
7962 mpd = cdst->mc_pg[csrc->mc_top];
7963 for (m2 = csrc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
7964 if (csrc->mc_flags & C_SUB)
7965 m3 = &m2->mc_xcursor->mx_cursor;
7966 else
7967 m3 = m2;
7968 if (!(m3->mc_flags & C_INITIALIZED) || m3->mc_top < csrc->mc_top)
7969 continue;
7970 if (m3 != cdst &&
7971 m3->mc_pg[csrc->mc_top] == mpd &&
7972 m3->mc_ki[csrc->mc_top] >= cdst->mc_ki[csrc->mc_top]) {
7973 m3->mc_ki[csrc->mc_top]++;
7974 }
7975 if (m3 !=csrc &&
7976 m3->mc_pg[csrc->mc_top] == mps &&
7977 m3->mc_ki[csrc->mc_top] == csrc->mc_ki[csrc->mc_top]) {
7978 m3->mc_pg[csrc->mc_top] = cdst->mc_pg[cdst->mc_top];
7979 m3->mc_ki[csrc->mc_top] = cdst->mc_ki[cdst->mc_top];
7980 m3->mc_ki[csrc->mc_top-1]++;
7981 }
7982 if (IS_LEAF(mps))
7983 XCURSOR_REFRESH(m3, csrc->mc_top, m3->mc_pg[csrc->mc_top]);
7984 }
7985 } else
7986 /* Adding on the right, bump others down */
7987 {
7988 for (m2 = csrc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
7989 if (csrc->mc_flags & C_SUB)
7990 m3 = &m2->mc_xcursor->mx_cursor;
7991 else
7992 m3 = m2;
7993 if (m3 == csrc) continue;
7994 if (!(m3->mc_flags & C_INITIALIZED) || m3->mc_top < csrc->mc_top)
7995 continue;
7996 if (m3->mc_pg[csrc->mc_top] == mps) {
7997 if (!m3->mc_ki[csrc->mc_top]) {
7998 m3->mc_pg[csrc->mc_top] = cdst->mc_pg[cdst->mc_top];
7999 m3->mc_ki[csrc->mc_top] = cdst->mc_ki[cdst->mc_top];
8000 m3->mc_ki[csrc->mc_top-1]--;
8001 } else {
8002 m3->mc_ki[csrc->mc_top]--;
8003 }
8004 if (IS_LEAF(mps))
8005 XCURSOR_REFRESH(m3, csrc->mc_top, m3->mc_pg[csrc->mc_top]);
8006 }
8007 }
8008 }
8009 }
8010
8011 /* Update the parent separators.
8012 */
8013 if (csrc->mc_ki[csrc->mc_top] == 0) {
8014 if (csrc->mc_ki[csrc->mc_top-1] != 0) {
8015 if (IS_LEAF2(csrc->mc_pg[csrc->mc_top])) {
8016 key.mv_data = LEAF2KEY(csrc->mc_pg[csrc->mc_top], 0, key.mv_size);
8017 } else {
8018 srcnode = NODEPTR(csrc->mc_pg[csrc->mc_top], 0);
8019 key.mv_size = NODEKSZ(srcnode);
8020 key.mv_data = NODEKEY(srcnode);
8021 }
8022 DPRINTF(("update separator for source page %"Z"u to [%s]",
8023 csrc->mc_pg[csrc->mc_top]->mp_pgno, DKEY(&key)));
8024 mdb_cursor_copy(csrc, &mn);
8025 mn.mc_snum--;
8026 mn.mc_top--;
8027 /* We want mdb_rebalance to find mn when doing fixups */
8028 WITH_CURSOR_TRACKING(mn,
8029 rc = mdb_update_key(&mn, &key));
8030 if (rc)
8031 return rc;
8032 }
8033 if (IS_BRANCH(csrc->mc_pg[csrc->mc_top])) {
8034 MDB_val nullkey;
8035 indx_t ix = csrc->mc_ki[csrc->mc_top];
8036 nullkey.mv_size = 0;
8037 csrc->mc_ki[csrc->mc_top] = 0;
8038 rc = mdb_update_key(csrc, &nullkey);
8039 csrc->mc_ki[csrc->mc_top] = ix;
8040 mdb_cassert(csrc, rc == MDB_SUCCESS);
8041 }
8042 }
8043
8044 if (cdst->mc_ki[cdst->mc_top] == 0) {
8045 if (cdst->mc_ki[cdst->mc_top-1] != 0) {
8046 if (IS_LEAF2(csrc->mc_pg[csrc->mc_top])) {
8047 key.mv_data = LEAF2KEY(cdst->mc_pg[cdst->mc_top], 0, key.mv_size);
8048 } else {
8049 srcnode = NODEPTR(cdst->mc_pg[cdst->mc_top], 0);
8050 key.mv_size = NODEKSZ(srcnode);
8051 key.mv_data = NODEKEY(srcnode);
8052 }
8053 DPRINTF(("update separator for destination page %"Z"u to [%s]",
8054 cdst->mc_pg[cdst->mc_top]->mp_pgno, DKEY(&key)));
8055 mdb_cursor_copy(cdst, &mn);
8056 mn.mc_snum--;
8057 mn.mc_top--;
8058 /* We want mdb_rebalance to find mn when doing fixups */
8059 WITH_CURSOR_TRACKING(mn,
8060 rc = mdb_update_key(&mn, &key));
8061 if (rc)
8062 return rc;
8063 }
8064 if (IS_BRANCH(cdst->mc_pg[cdst->mc_top])) {
8065 MDB_val nullkey;
8066 indx_t ix = cdst->mc_ki[cdst->mc_top];
8067 nullkey.mv_size = 0;
8068 cdst->mc_ki[cdst->mc_top] = 0;
8069 rc = mdb_update_key(cdst, &nullkey);
8070 cdst->mc_ki[cdst->mc_top] = ix;
8071 mdb_cassert(cdst, rc == MDB_SUCCESS);
8072 }
8073 }
8074
8075 return MDB_SUCCESS;
8076 }
8077
8078 /** Merge one page into another.
8079 * The nodes from the page pointed to by \b csrc will
8080 * be copied to the page pointed to by \b cdst and then
8081 * the \b csrc page will be freed.
8082 * @param[in] csrc Cursor pointing to the source page.
8083 * @param[in] cdst Cursor pointing to the destination page.
8084 * @return 0 on success, non-zero on failure.
8085 */
8086 static int
mdb_page_merge(MDB_cursor * csrc,MDB_cursor * cdst)8087 mdb_page_merge(MDB_cursor *csrc, MDB_cursor *cdst)
8088 {
8089 MDB_page *psrc, *pdst;
8090 MDB_node *srcnode;
8091 MDB_val key, data;
8092 unsigned nkeys;
8093 int rc;
8094 indx_t i, j;
8095
8096 psrc = csrc->mc_pg[csrc->mc_top];
8097 pdst = cdst->mc_pg[cdst->mc_top];
8098
8099 DPRINTF(("merging page %"Z"u into %"Z"u", psrc->mp_pgno, pdst->mp_pgno));
8100
8101 mdb_cassert(csrc, csrc->mc_snum > 1); /* can't merge root page */
8102 mdb_cassert(csrc, cdst->mc_snum > 1);
8103
8104 /* Mark dst as dirty. */
8105 if ((rc = mdb_page_touch(cdst)))
8106 return rc;
8107
8108 /* get dst page again now that we've touched it. */
8109 pdst = cdst->mc_pg[cdst->mc_top];
8110
8111 /* Move all nodes from src to dst.
8112 */
8113 j = nkeys = NUMKEYS(pdst);
8114 if (IS_LEAF2(psrc)) {
8115 key.mv_size = csrc->mc_db->md_pad;
8116 key.mv_data = METADATA(psrc);
8117 for (i = 0; i < NUMKEYS(psrc); i++, j++) {
8118 rc = mdb_node_add(cdst, j, &key, NULL, 0, 0);
8119 if (rc != MDB_SUCCESS)
8120 return rc;
8121 key.mv_data = (char *)key.mv_data + key.mv_size;
8122 }
8123 } else {
8124 for (i = 0; i < NUMKEYS(psrc); i++, j++) {
8125 srcnode = NODEPTR(psrc, i);
8126 if (i == 0 && IS_BRANCH(psrc)) {
8127 MDB_cursor mn;
8128 MDB_node *s2;
8129 mdb_cursor_copy(csrc, &mn);
8130 mn.mc_xcursor = NULL;
8131 /* must find the lowest key below src */
8132 rc = mdb_page_search_lowest(&mn);
8133 if (rc)
8134 return rc;
8135 if (IS_LEAF2(mn.mc_pg[mn.mc_top])) {
8136 key.mv_size = mn.mc_db->md_pad;
8137 key.mv_data = LEAF2KEY(mn.mc_pg[mn.mc_top], 0, key.mv_size);
8138 } else {
8139 s2 = NODEPTR(mn.mc_pg[mn.mc_top], 0);
8140 key.mv_size = NODEKSZ(s2);
8141 key.mv_data = NODEKEY(s2);
8142 }
8143 } else {
8144 key.mv_size = srcnode->mn_ksize;
8145 key.mv_data = NODEKEY(srcnode);
8146 }
8147
8148 data.mv_size = NODEDSZ(srcnode);
8149 data.mv_data = NODEDATA(srcnode);
8150 rc = mdb_node_add(cdst, j, &key, &data, NODEPGNO(srcnode), srcnode->mn_flags);
8151 if (rc != MDB_SUCCESS)
8152 return rc;
8153 }
8154 }
8155
8156 DPRINTF(("dst page %"Z"u now has %u keys (%.1f%% filled)",
8157 pdst->mp_pgno, NUMKEYS(pdst),
8158 (float)PAGEFILL(cdst->mc_txn->mt_env, pdst) / 10));
8159
8160 /* Unlink the src page from parent and add to free list.
8161 */
8162 csrc->mc_top--;
8163 mdb_node_del(csrc, 0);
8164 if (csrc->mc_ki[csrc->mc_top] == 0) {
8165 key.mv_size = 0;
8166 rc = mdb_update_key(csrc, &key);
8167 if (rc) {
8168 csrc->mc_top++;
8169 return rc;
8170 }
8171 }
8172 csrc->mc_top++;
8173
8174 psrc = csrc->mc_pg[csrc->mc_top];
8175 /* If not operating on FreeDB, allow this page to be reused
8176 * in this txn. Otherwise just add to free list.
8177 */
8178 rc = mdb_page_loose(csrc, psrc);
8179 if (rc)
8180 return rc;
8181 if (IS_LEAF(psrc))
8182 csrc->mc_db->md_leaf_pages--;
8183 else
8184 csrc->mc_db->md_branch_pages--;
8185 {
8186 /* Adjust other cursors pointing to mp */
8187 MDB_cursor *m2, *m3;
8188 MDB_dbi dbi = csrc->mc_dbi;
8189 unsigned int top = csrc->mc_top;
8190
8191 for (m2 = csrc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
8192 if (csrc->mc_flags & C_SUB)
8193 m3 = &m2->mc_xcursor->mx_cursor;
8194 else
8195 m3 = m2;
8196 if (m3 == csrc) continue;
8197 if (m3->mc_snum < csrc->mc_snum) continue;
8198 if (m3->mc_pg[top] == psrc) {
8199 m3->mc_pg[top] = pdst;
8200 m3->mc_ki[top] += nkeys;
8201 m3->mc_ki[top-1] = cdst->mc_ki[top-1];
8202 } else if (m3->mc_pg[top-1] == csrc->mc_pg[top-1] &&
8203 m3->mc_ki[top-1] > csrc->mc_ki[top-1]) {
8204 m3->mc_ki[top-1]--;
8205 }
8206 if (IS_LEAF(psrc))
8207 XCURSOR_REFRESH(m3, top, m3->mc_pg[top]);
8208 }
8209 }
8210 {
8211 unsigned int snum = cdst->mc_snum;
8212 uint16_t depth = cdst->mc_db->md_depth;
8213 mdb_cursor_pop(cdst);
8214 rc = mdb_rebalance(cdst);
8215 /* Did the tree height change? */
8216 if (depth != cdst->mc_db->md_depth)
8217 snum += cdst->mc_db->md_depth - depth;
8218 cdst->mc_snum = snum;
8219 cdst->mc_top = snum-1;
8220 }
8221 return rc;
8222 }
8223
8224 /** Copy the contents of a cursor.
8225 * @param[in] csrc The cursor to copy from.
8226 * @param[out] cdst The cursor to copy to.
8227 */
8228 static void
mdb_cursor_copy(const MDB_cursor * csrc,MDB_cursor * cdst)8229 mdb_cursor_copy(const MDB_cursor *csrc, MDB_cursor *cdst)
8230 {
8231 unsigned int i;
8232
8233 cdst->mc_txn = csrc->mc_txn;
8234 cdst->mc_dbi = csrc->mc_dbi;
8235 cdst->mc_db = csrc->mc_db;
8236 cdst->mc_dbx = csrc->mc_dbx;
8237 cdst->mc_snum = csrc->mc_snum;
8238 cdst->mc_top = csrc->mc_top;
8239 cdst->mc_flags = csrc->mc_flags;
8240
8241 for (i=0; i<csrc->mc_snum; i++) {
8242 cdst->mc_pg[i] = csrc->mc_pg[i];
8243 cdst->mc_ki[i] = csrc->mc_ki[i];
8244 }
8245 }
8246
8247 /** Rebalance the tree after a delete operation.
8248 * @param[in] mc Cursor pointing to the page where rebalancing
8249 * should begin.
8250 * @return 0 on success, non-zero on failure.
8251 */
8252 static int
mdb_rebalance(MDB_cursor * mc)8253 mdb_rebalance(MDB_cursor *mc)
8254 {
8255 MDB_node *node;
8256 int rc, fromleft;
8257 unsigned int ptop, minkeys, thresh;
8258 MDB_cursor mn;
8259 indx_t oldki;
8260
8261 if (IS_BRANCH(mc->mc_pg[mc->mc_top])) {
8262 minkeys = 2;
8263 thresh = 1;
8264 } else {
8265 minkeys = 1;
8266 thresh = FILL_THRESHOLD;
8267 }
8268 DPRINTF(("rebalancing %s page %"Z"u (has %u keys, %.1f%% full)",
8269 IS_LEAF(mc->mc_pg[mc->mc_top]) ? "leaf" : "branch",
8270 mdb_dbg_pgno(mc->mc_pg[mc->mc_top]), NUMKEYS(mc->mc_pg[mc->mc_top]),
8271 (float)PAGEFILL(mc->mc_txn->mt_env, mc->mc_pg[mc->mc_top]) / 10));
8272
8273 if (PAGEFILL(mc->mc_txn->mt_env, mc->mc_pg[mc->mc_top]) >= thresh &&
8274 NUMKEYS(mc->mc_pg[mc->mc_top]) >= minkeys) {
8275 DPRINTF(("no need to rebalance page %"Z"u, above fill threshold",
8276 mdb_dbg_pgno(mc->mc_pg[mc->mc_top])));
8277 return MDB_SUCCESS;
8278 }
8279
8280 if (mc->mc_snum < 2) {
8281 MDB_page *mp = mc->mc_pg[0];
8282 if (IS_SUBP(mp)) {
8283 DPUTS("Can't rebalance a subpage, ignoring");
8284 return MDB_SUCCESS;
8285 }
8286 if (NUMKEYS(mp) == 0) {
8287 DPUTS("tree is completely empty");
8288 mc->mc_db->md_root = P_INVALID;
8289 mc->mc_db->md_depth = 0;
8290 mc->mc_db->md_leaf_pages = 0;
8291 rc = mdb_midl_append(&mc->mc_txn->mt_free_pgs, mp->mp_pgno);
8292 if (rc)
8293 return rc;
8294 /* Adjust cursors pointing to mp */
8295 mc->mc_snum = 0;
8296 mc->mc_top = 0;
8297 mc->mc_flags &= ~C_INITIALIZED;
8298 {
8299 MDB_cursor *m2, *m3;
8300 MDB_dbi dbi = mc->mc_dbi;
8301
8302 for (m2 = mc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
8303 if (mc->mc_flags & C_SUB)
8304 m3 = &m2->mc_xcursor->mx_cursor;
8305 else
8306 m3 = m2;
8307 if (!(m3->mc_flags & C_INITIALIZED) || (m3->mc_snum < mc->mc_snum))
8308 continue;
8309 if (m3->mc_pg[0] == mp) {
8310 m3->mc_snum = 0;
8311 m3->mc_top = 0;
8312 m3->mc_flags &= ~C_INITIALIZED;
8313 }
8314 }
8315 }
8316 } else if (IS_BRANCH(mp) && NUMKEYS(mp) == 1) {
8317 int i;
8318 DPUTS("collapsing root page!");
8319 rc = mdb_midl_append(&mc->mc_txn->mt_free_pgs, mp->mp_pgno);
8320 if (rc)
8321 return rc;
8322 mc->mc_db->md_root = NODEPGNO(NODEPTR(mp, 0));
8323 rc = mdb_page_get(mc, mc->mc_db->md_root, &mc->mc_pg[0], NULL);
8324 if (rc)
8325 return rc;
8326 mc->mc_db->md_depth--;
8327 mc->mc_db->md_branch_pages--;
8328 mc->mc_ki[0] = mc->mc_ki[1];
8329 for (i = 1; i<mc->mc_db->md_depth; i++) {
8330 mc->mc_pg[i] = mc->mc_pg[i+1];
8331 mc->mc_ki[i] = mc->mc_ki[i+1];
8332 }
8333 {
8334 /* Adjust other cursors pointing to mp */
8335 MDB_cursor *m2, *m3;
8336 MDB_dbi dbi = mc->mc_dbi;
8337
8338 for (m2 = mc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
8339 if (mc->mc_flags & C_SUB)
8340 m3 = &m2->mc_xcursor->mx_cursor;
8341 else
8342 m3 = m2;
8343 if (m3 == mc) continue;
8344 if (!(m3->mc_flags & C_INITIALIZED))
8345 continue;
8346 if (m3->mc_pg[0] == mp) {
8347 for (i=0; i<mc->mc_db->md_depth; i++) {
8348 m3->mc_pg[i] = m3->mc_pg[i+1];
8349 m3->mc_ki[i] = m3->mc_ki[i+1];
8350 }
8351 m3->mc_snum--;
8352 m3->mc_top--;
8353 }
8354 }
8355 }
8356 } else
8357 DPUTS("root page doesn't need rebalancing");
8358 return MDB_SUCCESS;
8359 }
8360
8361 /* The parent (branch page) must have at least 2 pointers,
8362 * otherwise the tree is invalid.
8363 */
8364 ptop = mc->mc_top-1;
8365 mdb_cassert(mc, NUMKEYS(mc->mc_pg[ptop]) > 1);
8366
8367 /* Leaf page fill factor is below the threshold.
8368 * Try to move keys from left or right neighbor, or
8369 * merge with a neighbor page.
8370 */
8371
8372 /* Find neighbors.
8373 */
8374 mdb_cursor_copy(mc, &mn);
8375 mn.mc_xcursor = NULL;
8376
8377 oldki = mc->mc_ki[mc->mc_top];
8378 if (mc->mc_ki[ptop] == 0) {
8379 /* We're the leftmost leaf in our parent.
8380 */
8381 DPUTS("reading right neighbor");
8382 mn.mc_ki[ptop]++;
8383 node = NODEPTR(mc->mc_pg[ptop], mn.mc_ki[ptop]);
8384 rc = mdb_page_get(mc, NODEPGNO(node), &mn.mc_pg[mn.mc_top], NULL);
8385 if (rc)
8386 return rc;
8387 mn.mc_ki[mn.mc_top] = 0;
8388 mc->mc_ki[mc->mc_top] = NUMKEYS(mc->mc_pg[mc->mc_top]);
8389 fromleft = 0;
8390 } else {
8391 /* There is at least one neighbor to the left.
8392 */
8393 DPUTS("reading left neighbor");
8394 mn.mc_ki[ptop]--;
8395 node = NODEPTR(mc->mc_pg[ptop], mn.mc_ki[ptop]);
8396 rc = mdb_page_get(mc, NODEPGNO(node), &mn.mc_pg[mn.mc_top], NULL);
8397 if (rc)
8398 return rc;
8399 mn.mc_ki[mn.mc_top] = NUMKEYS(mn.mc_pg[mn.mc_top]) - 1;
8400 mc->mc_ki[mc->mc_top] = 0;
8401 fromleft = 1;
8402 }
8403
8404 DPRINTF(("found neighbor page %"Z"u (%u keys, %.1f%% full)",
8405 mn.mc_pg[mn.mc_top]->mp_pgno, NUMKEYS(mn.mc_pg[mn.mc_top]),
8406 (float)PAGEFILL(mc->mc_txn->mt_env, mn.mc_pg[mn.mc_top]) / 10));
8407
8408 /* If the neighbor page is above threshold and has enough keys,
8409 * move one key from it. Otherwise we should try to merge them.
8410 * (A branch page must never have less than 2 keys.)
8411 */
8412 if (PAGEFILL(mc->mc_txn->mt_env, mn.mc_pg[mn.mc_top]) >= thresh && NUMKEYS(mn.mc_pg[mn.mc_top]) > minkeys) {
8413 rc = mdb_node_move(&mn, mc, fromleft);
8414 if (fromleft) {
8415 /* if we inserted on left, bump position up */
8416 oldki++;
8417 }
8418 } else {
8419 if (!fromleft) {
8420 rc = mdb_page_merge(&mn, mc);
8421 } else {
8422 oldki += NUMKEYS(mn.mc_pg[mn.mc_top]);
8423 mn.mc_ki[mn.mc_top] += mc->mc_ki[mn.mc_top] + 1;
8424 /* We want mdb_rebalance to find mn when doing fixups */
8425 WITH_CURSOR_TRACKING(mn,
8426 rc = mdb_page_merge(mc, &mn));
8427 mdb_cursor_copy(&mn, mc);
8428 }
8429 mc->mc_flags &= ~C_EOF;
8430 }
8431 mc->mc_ki[mc->mc_top] = oldki;
8432 return rc;
8433 }
8434
8435 /** Complete a delete operation started by #mdb_cursor_del(). */
8436 static int
mdb_cursor_del0(MDB_cursor * mc)8437 mdb_cursor_del0(MDB_cursor *mc)
8438 {
8439 int rc;
8440 MDB_page *mp;
8441 indx_t ki;
8442 unsigned int nkeys;
8443 MDB_cursor *m2, *m3;
8444 MDB_dbi dbi = mc->mc_dbi;
8445
8446 ki = mc->mc_ki[mc->mc_top];
8447 mp = mc->mc_pg[mc->mc_top];
8448 mdb_node_del(mc, mc->mc_db->md_pad);
8449 mc->mc_db->md_entries--;
8450 {
8451 /* Adjust other cursors pointing to mp */
8452 for (m2 = mc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
8453 m3 = (mc->mc_flags & C_SUB) ? &m2->mc_xcursor->mx_cursor : m2;
8454 if (! (m2->mc_flags & m3->mc_flags & C_INITIALIZED))
8455 continue;
8456 if (m3 == mc || m3->mc_snum < mc->mc_snum)
8457 continue;
8458 if (m3->mc_pg[mc->mc_top] == mp) {
8459 if (m3->mc_ki[mc->mc_top] == ki) {
8460 m3->mc_flags |= C_DEL;
8461 if (mc->mc_db->md_flags & MDB_DUPSORT) {
8462 /* Sub-cursor referred into dataset which is gone */
8463 m3->mc_xcursor->mx_cursor.mc_flags &= ~(C_INITIALIZED|C_EOF);
8464 }
8465 continue;
8466 } else if (m3->mc_ki[mc->mc_top] > ki) {
8467 m3->mc_ki[mc->mc_top]--;
8468 }
8469 XCURSOR_REFRESH(m3, mc->mc_top, mp);
8470 }
8471 }
8472 }
8473 rc = mdb_rebalance(mc);
8474 if (rc)
8475 goto fail;
8476
8477 /* DB is totally empty now, just bail out.
8478 * Other cursors adjustments were already done
8479 * by mdb_rebalance and aren't needed here.
8480 */
8481 if (!mc->mc_snum) {
8482 mc->mc_flags |= C_EOF;
8483 return rc;
8484 }
8485
8486 mp = mc->mc_pg[mc->mc_top];
8487 nkeys = NUMKEYS(mp);
8488
8489 /* Adjust other cursors pointing to mp */
8490 for (m2 = mc->mc_txn->mt_cursors[dbi]; !rc && m2; m2=m2->mc_next) {
8491 m3 = (mc->mc_flags & C_SUB) ? &m2->mc_xcursor->mx_cursor : m2;
8492 if (!(m2->mc_flags & m3->mc_flags & C_INITIALIZED))
8493 continue;
8494 if (m3->mc_snum < mc->mc_snum)
8495 continue;
8496 if (m3->mc_pg[mc->mc_top] == mp) {
8497 if (m3->mc_ki[mc->mc_top] >= mc->mc_ki[mc->mc_top]) {
8498 /* if m3 points past last node in page, find next sibling */
8499 if (m3->mc_ki[mc->mc_top] >= nkeys) {
8500 rc = mdb_cursor_sibling(m3, 1);
8501 if (rc == MDB_NOTFOUND) {
8502 m3->mc_flags |= C_EOF;
8503 rc = MDB_SUCCESS;
8504 continue;
8505 }
8506 if (rc)
8507 goto fail;
8508 }
8509 if (m3->mc_xcursor && !(m3->mc_flags & C_EOF)) {
8510 MDB_node *node = NODEPTR(m3->mc_pg[m3->mc_top], m3->mc_ki[m3->mc_top]);
8511 /* If this node has dupdata, it may need to be reinited
8512 * because its data has moved.
8513 * If the xcursor was not initd it must be reinited.
8514 * Else if node points to a subDB, nothing is needed.
8515 * Else (xcursor was initd, not a subDB) needs mc_pg[0] reset.
8516 */
8517 if (node->mn_flags & F_DUPDATA) {
8518 if (m3->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED) {
8519 if (!(node->mn_flags & F_SUBDATA))
8520 m3->mc_xcursor->mx_cursor.mc_pg[0] = NODEDATA(node);
8521 } else {
8522 mdb_xcursor_init1(m3, node);
8523 rc = mdb_cursor_first(&m3->mc_xcursor->mx_cursor, NULL, NULL);
8524 if (rc)
8525 goto fail;
8526 }
8527 }
8528 m3->mc_xcursor->mx_cursor.mc_flags |= C_DEL;
8529 }
8530 }
8531 }
8532 }
8533 mc->mc_flags |= C_DEL;
8534
8535 fail:
8536 if (rc)
8537 mc->mc_txn->mt_flags |= MDB_TXN_ERROR;
8538 return rc;
8539 }
8540
8541 int
mdb_del(MDB_txn * txn,MDB_dbi dbi,MDB_val * key,MDB_val * data)8542 mdb_del(MDB_txn *txn, MDB_dbi dbi,
8543 MDB_val *key, MDB_val *data)
8544 {
8545 if (!key || !TXN_DBI_EXIST(txn, dbi, DB_USRVALID))
8546 return EINVAL;
8547
8548 if (txn->mt_flags & (MDB_TXN_RDONLY|MDB_TXN_BLOCKED))
8549 return (txn->mt_flags & MDB_TXN_RDONLY) ? EACCES : MDB_BAD_TXN;
8550
8551 if (!F_ISSET(txn->mt_dbs[dbi].md_flags, MDB_DUPSORT)) {
8552 /* must ignore any data */
8553 data = NULL;
8554 }
8555
8556 return mdb_del0(txn, dbi, key, data, 0);
8557 }
8558
8559 static int
mdb_del0(MDB_txn * txn,MDB_dbi dbi,MDB_val * key,MDB_val * data,unsigned flags)8560 mdb_del0(MDB_txn *txn, MDB_dbi dbi,
8561 MDB_val *key, MDB_val *data, unsigned flags)
8562 {
8563 MDB_cursor mc;
8564 MDB_xcursor mx;
8565 MDB_cursor_op op;
8566 MDB_val rdata, *xdata;
8567 int rc, exact = 0;
8568 DKBUF;
8569
8570 DPRINTF(("====> delete db %u key [%s]", dbi, DKEY(key)));
8571
8572 mdb_cursor_init(&mc, txn, dbi, &mx);
8573
8574 if (data) {
8575 op = MDB_GET_BOTH;
8576 rdata = *data;
8577 xdata = &rdata;
8578 } else {
8579 op = MDB_SET;
8580 xdata = NULL;
8581 flags |= MDB_NODUPDATA;
8582 }
8583 rc = mdb_cursor_set(&mc, key, xdata, op, &exact);
8584 if (rc == 0) {
8585 /* let mdb_page_split know about this cursor if needed:
8586 * delete will trigger a rebalance; if it needs to move
8587 * a node from one page to another, it will have to
8588 * update the parent's separator key(s). If the new sepkey
8589 * is larger than the current one, the parent page may
8590 * run out of space, triggering a split. We need this
8591 * cursor to be consistent until the end of the rebalance.
8592 */
8593 mc.mc_flags |= C_UNTRACK;
8594 mc.mc_next = txn->mt_cursors[dbi];
8595 txn->mt_cursors[dbi] = &mc;
8596 rc = mdb_cursor_del(&mc, flags);
8597 txn->mt_cursors[dbi] = mc.mc_next;
8598 }
8599 return rc;
8600 }
8601
8602 /** Split a page and insert a new node.
8603 * Set #MDB_TXN_ERROR on failure.
8604 * @param[in,out] mc Cursor pointing to the page and desired insertion index.
8605 * The cursor will be updated to point to the actual page and index where
8606 * the node got inserted after the split.
8607 * @param[in] newkey The key for the newly inserted node.
8608 * @param[in] newdata The data for the newly inserted node.
8609 * @param[in] newpgno The page number, if the new node is a branch node.
8610 * @param[in] nflags The #NODE_ADD_FLAGS for the new node.
8611 * @return 0 on success, non-zero on failure.
8612 */
8613 static int
mdb_page_split(MDB_cursor * mc,MDB_val * newkey,MDB_val * newdata,pgno_t newpgno,unsigned int nflags)8614 mdb_page_split(MDB_cursor *mc, MDB_val *newkey, MDB_val *newdata, pgno_t newpgno,
8615 unsigned int nflags)
8616 {
8617 unsigned int flags;
8618 int rc = MDB_SUCCESS, new_root = 0, did_split = 0;
8619 indx_t newindx;
8620 pgno_t pgno = 0;
8621 int i, j, split_indx, nkeys, pmax;
8622 MDB_env *env = mc->mc_txn->mt_env;
8623 MDB_node *node;
8624 MDB_val sepkey, rkey, xdata, *rdata = &xdata;
8625 MDB_page *copy = NULL;
8626 MDB_page *mp, *rp, *pp;
8627 int ptop;
8628 MDB_cursor mn;
8629 DKBUF;
8630
8631 mp = mc->mc_pg[mc->mc_top];
8632 newindx = mc->mc_ki[mc->mc_top];
8633 nkeys = NUMKEYS(mp);
8634
8635 DPRINTF(("-----> splitting %s page %"Z"u and adding [%s] at index %i/%i",
8636 IS_LEAF(mp) ? "leaf" : "branch", mp->mp_pgno,
8637 DKEY(newkey), mc->mc_ki[mc->mc_top], nkeys));
8638
8639 /* Create a right sibling. */
8640 if ((rc = mdb_page_new(mc, mp->mp_flags, 1, &rp)))
8641 return rc;
8642 rp->mp_pad = mp->mp_pad;
8643 DPRINTF(("new right sibling: page %"Z"u", rp->mp_pgno));
8644
8645 /* Usually when splitting the root page, the cursor
8646 * height is 1. But when called from mdb_update_key,
8647 * the cursor height may be greater because it walks
8648 * up the stack while finding the branch slot to update.
8649 */
8650 if (mc->mc_top < 1) {
8651 if ((rc = mdb_page_new(mc, P_BRANCH, 1, &pp)))
8652 goto done;
8653 /* shift current top to make room for new parent */
8654 for (i=mc->mc_snum; i>0; i--) {
8655 mc->mc_pg[i] = mc->mc_pg[i-1];
8656 mc->mc_ki[i] = mc->mc_ki[i-1];
8657 }
8658 mc->mc_pg[0] = pp;
8659 mc->mc_ki[0] = 0;
8660 mc->mc_db->md_root = pp->mp_pgno;
8661 DPRINTF(("root split! new root = %"Z"u", pp->mp_pgno));
8662 new_root = mc->mc_db->md_depth++;
8663
8664 /* Add left (implicit) pointer. */
8665 if ((rc = mdb_node_add(mc, 0, NULL, NULL, mp->mp_pgno, 0)) != MDB_SUCCESS) {
8666 /* undo the pre-push */
8667 mc->mc_pg[0] = mc->mc_pg[1];
8668 mc->mc_ki[0] = mc->mc_ki[1];
8669 mc->mc_db->md_root = mp->mp_pgno;
8670 mc->mc_db->md_depth--;
8671 goto done;
8672 }
8673 mc->mc_snum++;
8674 mc->mc_top++;
8675 ptop = 0;
8676 } else {
8677 ptop = mc->mc_top-1;
8678 DPRINTF(("parent branch page is %"Z"u", mc->mc_pg[ptop]->mp_pgno));
8679 }
8680
8681 mdb_cursor_copy(mc, &mn);
8682 mn.mc_xcursor = NULL;
8683 mn.mc_pg[mn.mc_top] = rp;
8684 mn.mc_ki[ptop] = mc->mc_ki[ptop]+1;
8685
8686 if (nflags & MDB_APPEND) {
8687 mn.mc_ki[mn.mc_top] = 0;
8688 sepkey = *newkey;
8689 split_indx = newindx;
8690 nkeys = 0;
8691 } else {
8692
8693 split_indx = (nkeys+1) / 2;
8694
8695 if (IS_LEAF2(rp)) {
8696 char *split, *ins;
8697 int x;
8698 unsigned int lsize, rsize, ksize;
8699 /* Move half of the keys to the right sibling */
8700 x = mc->mc_ki[mc->mc_top] - split_indx;
8701 ksize = mc->mc_db->md_pad;
8702 split = LEAF2KEY(mp, split_indx, ksize);
8703 rsize = (nkeys - split_indx) * ksize;
8704 lsize = (nkeys - split_indx) * sizeof(indx_t);
8705 mp->mp_lower -= lsize;
8706 rp->mp_lower += lsize;
8707 mp->mp_upper += rsize - lsize;
8708 rp->mp_upper -= rsize - lsize;
8709 sepkey.mv_size = ksize;
8710 if (newindx == split_indx) {
8711 sepkey.mv_data = newkey->mv_data;
8712 } else {
8713 sepkey.mv_data = split;
8714 }
8715 if (x<0) {
8716 ins = LEAF2KEY(mp, mc->mc_ki[mc->mc_top], ksize);
8717 memcpy(rp->mp_ptrs, split, rsize);
8718 sepkey.mv_data = rp->mp_ptrs;
8719 memmove(ins+ksize, ins, (split_indx - mc->mc_ki[mc->mc_top]) * ksize);
8720 memcpy(ins, newkey->mv_data, ksize);
8721 mp->mp_lower += sizeof(indx_t);
8722 mp->mp_upper -= ksize - sizeof(indx_t);
8723 } else {
8724 if (x)
8725 memcpy(rp->mp_ptrs, split, x * ksize);
8726 ins = LEAF2KEY(rp, x, ksize);
8727 memcpy(ins, newkey->mv_data, ksize);
8728 memcpy(ins+ksize, split + x * ksize, rsize - x * ksize);
8729 rp->mp_lower += sizeof(indx_t);
8730 rp->mp_upper -= ksize - sizeof(indx_t);
8731 mc->mc_ki[mc->mc_top] = x;
8732 }
8733 } else {
8734 int psize, nsize, k;
8735 /* Maximum free space in an empty page */
8736 pmax = env->me_psize - PAGEHDRSZ;
8737 if (IS_LEAF(mp))
8738 nsize = mdb_leaf_size(env, newkey, newdata);
8739 else
8740 nsize = mdb_branch_size(env, newkey);
8741 nsize = EVEN(nsize);
8742
8743 /* grab a page to hold a temporary copy */
8744 copy = mdb_page_malloc(mc->mc_txn, 1);
8745 if (copy == NULL) {
8746 rc = ENOMEM;
8747 goto done;
8748 }
8749 copy->mp_pgno = mp->mp_pgno;
8750 copy->mp_flags = mp->mp_flags;
8751 copy->mp_lower = (PAGEHDRSZ-PAGEBASE);
8752 copy->mp_upper = env->me_psize - PAGEBASE;
8753
8754 /* prepare to insert */
8755 for (i=0, j=0; i<nkeys; i++) {
8756 if (i == newindx) {
8757 copy->mp_ptrs[j++] = 0;
8758 }
8759 copy->mp_ptrs[j++] = mp->mp_ptrs[i];
8760 }
8761
8762 /* When items are relatively large the split point needs
8763 * to be checked, because being off-by-one will make the
8764 * difference between success or failure in mdb_node_add.
8765 *
8766 * It's also relevant if a page happens to be laid out
8767 * such that one half of its nodes are all "small" and
8768 * the other half of its nodes are "large." If the new
8769 * item is also "large" and falls on the half with
8770 * "large" nodes, it also may not fit.
8771 *
8772 * As a final tweak, if the new item goes on the last
8773 * spot on the page (and thus, onto the new page), bias
8774 * the split so the new page is emptier than the old page.
8775 * This yields better packing during sequential inserts.
8776 */
8777 if (nkeys < 32 || nsize > pmax/16 || newindx >= nkeys) {
8778 /* Find split point */
8779 psize = 0;
8780 if (newindx <= split_indx || newindx >= nkeys) {
8781 i = 0; j = 1;
8782 k = newindx >= nkeys ? nkeys : split_indx+1+IS_LEAF(mp);
8783 } else {
8784 i = nkeys; j = -1;
8785 k = split_indx-1;
8786 }
8787 for (; i!=k; i+=j) {
8788 if (i == newindx) {
8789 psize += nsize;
8790 node = NULL;
8791 } else {
8792 node = (MDB_node *)((char *)mp + copy->mp_ptrs[i] + PAGEBASE);
8793 psize += NODESIZE + NODEKSZ(node) + sizeof(indx_t);
8794 if (IS_LEAF(mp)) {
8795 if (F_ISSET(node->mn_flags, F_BIGDATA))
8796 psize += sizeof(pgno_t);
8797 else
8798 psize += NODEDSZ(node);
8799 }
8800 psize = EVEN(psize);
8801 }
8802 if (psize > pmax || i == k-j) {
8803 split_indx = i + (j<0);
8804 break;
8805 }
8806 }
8807 }
8808 if (split_indx == newindx) {
8809 sepkey.mv_size = newkey->mv_size;
8810 sepkey.mv_data = newkey->mv_data;
8811 } else {
8812 node = (MDB_node *)((char *)mp + copy->mp_ptrs[split_indx] + PAGEBASE);
8813 sepkey.mv_size = node->mn_ksize;
8814 sepkey.mv_data = NODEKEY(node);
8815 }
8816 }
8817 }
8818
8819 DPRINTF(("separator is %d [%s]", split_indx, DKEY(&sepkey)));
8820
8821 /* Copy separator key to the parent.
8822 */
8823 if (SIZELEFT(mn.mc_pg[ptop]) < mdb_branch_size(env, &sepkey)) {
8824 int snum = mc->mc_snum;
8825 mn.mc_snum--;
8826 mn.mc_top--;
8827 did_split = 1;
8828 /* We want other splits to find mn when doing fixups */
8829 WITH_CURSOR_TRACKING(mn,
8830 rc = mdb_page_split(&mn, &sepkey, NULL, rp->mp_pgno, 0));
8831 if (rc)
8832 goto done;
8833
8834 /* root split? */
8835 if (mc->mc_snum > snum) {
8836 ptop++;
8837 }
8838 /* Right page might now have changed parent.
8839 * Check if left page also changed parent.
8840 */
8841 if (mn.mc_pg[ptop] != mc->mc_pg[ptop] &&
8842 mc->mc_ki[ptop] >= NUMKEYS(mc->mc_pg[ptop])) {
8843 for (i=0; i<ptop; i++) {
8844 mc->mc_pg[i] = mn.mc_pg[i];
8845 mc->mc_ki[i] = mn.mc_ki[i];
8846 }
8847 mc->mc_pg[ptop] = mn.mc_pg[ptop];
8848 if (mn.mc_ki[ptop]) {
8849 mc->mc_ki[ptop] = mn.mc_ki[ptop] - 1;
8850 } else {
8851 /* find right page's left sibling */
8852 mc->mc_ki[ptop] = mn.mc_ki[ptop];
8853 mdb_cursor_sibling(mc, 0);
8854 }
8855 }
8856 } else {
8857 mn.mc_top--;
8858 rc = mdb_node_add(&mn, mn.mc_ki[ptop], &sepkey, NULL, rp->mp_pgno, 0);
8859 mn.mc_top++;
8860 }
8861 if (rc != MDB_SUCCESS) {
8862 goto done;
8863 }
8864 if (nflags & MDB_APPEND) {
8865 mc->mc_pg[mc->mc_top] = rp;
8866 mc->mc_ki[mc->mc_top] = 0;
8867 rc = mdb_node_add(mc, 0, newkey, newdata, newpgno, nflags);
8868 if (rc)
8869 goto done;
8870 for (i=0; i<mc->mc_top; i++)
8871 mc->mc_ki[i] = mn.mc_ki[i];
8872 } else if (!IS_LEAF2(mp)) {
8873 /* Move nodes */
8874 mc->mc_pg[mc->mc_top] = rp;
8875 i = split_indx;
8876 j = 0;
8877 do {
8878 if (i == newindx) {
8879 rkey.mv_data = newkey->mv_data;
8880 rkey.mv_size = newkey->mv_size;
8881 if (IS_LEAF(mp)) {
8882 rdata = newdata;
8883 } else
8884 pgno = newpgno;
8885 flags = nflags;
8886 /* Update index for the new key. */
8887 mc->mc_ki[mc->mc_top] = j;
8888 } else {
8889 node = (MDB_node *)((char *)mp + copy->mp_ptrs[i] + PAGEBASE);
8890 rkey.mv_data = NODEKEY(node);
8891 rkey.mv_size = node->mn_ksize;
8892 if (IS_LEAF(mp)) {
8893 xdata.mv_data = NODEDATA(node);
8894 xdata.mv_size = NODEDSZ(node);
8895 rdata = &xdata;
8896 } else
8897 pgno = NODEPGNO(node);
8898 flags = node->mn_flags;
8899 }
8900
8901 if (!IS_LEAF(mp) && j == 0) {
8902 /* First branch index doesn't need key data. */
8903 rkey.mv_size = 0;
8904 }
8905
8906 rc = mdb_node_add(mc, j, &rkey, rdata, pgno, flags);
8907 if (rc)
8908 goto done;
8909 if (i == nkeys) {
8910 i = 0;
8911 j = 0;
8912 mc->mc_pg[mc->mc_top] = copy;
8913 } else {
8914 i++;
8915 j++;
8916 }
8917 } while (i != split_indx);
8918
8919 nkeys = NUMKEYS(copy);
8920 for (i=0; i<nkeys; i++)
8921 mp->mp_ptrs[i] = copy->mp_ptrs[i];
8922 mp->mp_lower = copy->mp_lower;
8923 mp->mp_upper = copy->mp_upper;
8924 memcpy(NODEPTR(mp, nkeys-1), NODEPTR(copy, nkeys-1),
8925 env->me_psize - copy->mp_upper - PAGEBASE);
8926
8927 /* reset back to original page */
8928 if (newindx < split_indx) {
8929 mc->mc_pg[mc->mc_top] = mp;
8930 } else {
8931 mc->mc_pg[mc->mc_top] = rp;
8932 mc->mc_ki[ptop]++;
8933 /* Make sure mc_ki is still valid.
8934 */
8935 if (mn.mc_pg[ptop] != mc->mc_pg[ptop] &&
8936 mc->mc_ki[ptop] >= NUMKEYS(mc->mc_pg[ptop])) {
8937 for (i=0; i<=ptop; i++) {
8938 mc->mc_pg[i] = mn.mc_pg[i];
8939 mc->mc_ki[i] = mn.mc_ki[i];
8940 }
8941 }
8942 }
8943 if (nflags & MDB_RESERVE) {
8944 node = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
8945 if (!(node->mn_flags & F_BIGDATA))
8946 newdata->mv_data = NODEDATA(node);
8947 }
8948 } else {
8949 if (newindx >= split_indx) {
8950 mc->mc_pg[mc->mc_top] = rp;
8951 mc->mc_ki[ptop]++;
8952 /* Make sure mc_ki is still valid.
8953 */
8954 if (mn.mc_pg[ptop] != mc->mc_pg[ptop] &&
8955 mc->mc_ki[ptop] >= NUMKEYS(mc->mc_pg[ptop])) {
8956 for (i=0; i<=ptop; i++) {
8957 mc->mc_pg[i] = mn.mc_pg[i];
8958 mc->mc_ki[i] = mn.mc_ki[i];
8959 }
8960 }
8961 }
8962 }
8963
8964 {
8965 /* Adjust other cursors pointing to mp */
8966 MDB_cursor *m2, *m3;
8967 MDB_dbi dbi = mc->mc_dbi;
8968 nkeys = NUMKEYS(mp);
8969
8970 for (m2 = mc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
8971 if (mc->mc_flags & C_SUB)
8972 m3 = &m2->mc_xcursor->mx_cursor;
8973 else
8974 m3 = m2;
8975 if (m3 == mc)
8976 continue;
8977 if (!(m2->mc_flags & m3->mc_flags & C_INITIALIZED))
8978 continue;
8979 if (new_root) {
8980 int k;
8981 /* sub cursors may be on different DB */
8982 if (m3->mc_pg[0] != mp)
8983 continue;
8984 /* root split */
8985 for (k=new_root; k>=0; k--) {
8986 m3->mc_ki[k+1] = m3->mc_ki[k];
8987 m3->mc_pg[k+1] = m3->mc_pg[k];
8988 }
8989 if (m3->mc_ki[0] >= nkeys) {
8990 m3->mc_ki[0] = 1;
8991 } else {
8992 m3->mc_ki[0] = 0;
8993 }
8994 m3->mc_pg[0] = mc->mc_pg[0];
8995 m3->mc_snum++;
8996 m3->mc_top++;
8997 }
8998 if (m3->mc_top >= mc->mc_top && m3->mc_pg[mc->mc_top] == mp) {
8999 if (m3->mc_ki[mc->mc_top] >= newindx && !(nflags & MDB_SPLIT_REPLACE))
9000 m3->mc_ki[mc->mc_top]++;
9001 if (m3->mc_ki[mc->mc_top] >= nkeys) {
9002 m3->mc_pg[mc->mc_top] = rp;
9003 m3->mc_ki[mc->mc_top] -= nkeys;
9004 for (i=0; i<mc->mc_top; i++) {
9005 m3->mc_ki[i] = mn.mc_ki[i];
9006 m3->mc_pg[i] = mn.mc_pg[i];
9007 }
9008 }
9009 } else if (!did_split && m3->mc_top >= ptop && m3->mc_pg[ptop] == mc->mc_pg[ptop] &&
9010 m3->mc_ki[ptop] >= mc->mc_ki[ptop]) {
9011 m3->mc_ki[ptop]++;
9012 }
9013 if (IS_LEAF(mp))
9014 XCURSOR_REFRESH(m3, mc->mc_top, m3->mc_pg[mc->mc_top]);
9015 }
9016 }
9017 DPRINTF(("mp left: %d, rp left: %d", SIZELEFT(mp), SIZELEFT(rp)));
9018
9019 done:
9020 if (copy) /* tmp page */
9021 mdb_page_free(env, copy);
9022 if (rc)
9023 mc->mc_txn->mt_flags |= MDB_TXN_ERROR;
9024 return rc;
9025 }
9026
9027 int
mdb_put(MDB_txn * txn,MDB_dbi dbi,MDB_val * key,MDB_val * data,unsigned int flags)9028 mdb_put(MDB_txn *txn, MDB_dbi dbi,
9029 MDB_val *key, MDB_val *data, unsigned int flags)
9030 {
9031 MDB_cursor mc;
9032 MDB_xcursor mx;
9033 int rc;
9034
9035 if (!key || !data || !TXN_DBI_EXIST(txn, dbi, DB_USRVALID))
9036 return EINVAL;
9037
9038 if (flags & ~(MDB_NOOVERWRITE|MDB_NODUPDATA|MDB_RESERVE|MDB_APPEND|MDB_APPENDDUP))
9039 return EINVAL;
9040
9041 if (txn->mt_flags & (MDB_TXN_RDONLY|MDB_TXN_BLOCKED))
9042 return (txn->mt_flags & MDB_TXN_RDONLY) ? EACCES : MDB_BAD_TXN;
9043
9044 mdb_cursor_init(&mc, txn, dbi, &mx);
9045 mc.mc_next = txn->mt_cursors[dbi];
9046 txn->mt_cursors[dbi] = &mc;
9047 rc = mdb_cursor_put(&mc, key, data, flags);
9048 txn->mt_cursors[dbi] = mc.mc_next;
9049 return rc;
9050 }
9051
9052 #ifndef MDB_WBUF
9053 #define MDB_WBUF (1024*1024)
9054 #endif
9055 #define MDB_EOF 0x10 /**< #mdb_env_copyfd1() is done reading */
9056
9057 /** State needed for a double-buffering compacting copy. */
9058 typedef struct mdb_copy {
9059 MDB_env *mc_env;
9060 MDB_txn *mc_txn;
9061 pthread_mutex_t mc_mutex;
9062 pthread_cond_t mc_cond; /**< Condition variable for #mc_new */
9063 char *mc_wbuf[2];
9064 char *mc_over[2];
9065 int mc_wlen[2];
9066 int mc_olen[2];
9067 pgno_t mc_next_pgno;
9068 HANDLE mc_fd;
9069 int mc_toggle; /**< Buffer number in provider */
9070 int mc_new; /**< (0-2 buffers to write) | (#MDB_EOF at end) */
9071 /** Error code. Never cleared if set. Both threads can set nonzero
9072 * to fail the copy. Not mutex-protected, LMDB expects atomic int.
9073 */
9074 volatile int mc_error;
9075 } mdb_copy;
9076
9077 /** Dedicated writer thread for compacting copy. */
9078 static THREAD_RET ESECT CALL_CONV
mdb_env_copythr(void * arg)9079 mdb_env_copythr(void *arg)
9080 {
9081 mdb_copy *my = arg;
9082 char *ptr;
9083 int toggle = 0, wsize, rc;
9084 #ifdef _WIN32
9085 DWORD len;
9086 #define DO_WRITE(rc, fd, ptr, w2, len) rc = WriteFile(fd, ptr, w2, &len, NULL)
9087 #else
9088 int len;
9089 #define DO_WRITE(rc, fd, ptr, w2, len) len = write(fd, ptr, w2); rc = (len >= 0)
9090 #ifdef SIGPIPE
9091 sigset_t set;
9092 sigemptyset(&set);
9093 sigaddset(&set, SIGPIPE);
9094 if ((rc = pthread_sigmask(SIG_BLOCK, &set, NULL)) != 0)
9095 my->mc_error = rc;
9096 #endif
9097 #endif
9098
9099 pthread_mutex_lock(&my->mc_mutex);
9100 for(;;) {
9101 while (!my->mc_new)
9102 pthread_cond_wait(&my->mc_cond, &my->mc_mutex);
9103 if (my->mc_new == 0 + MDB_EOF) /* 0 buffers, just EOF */
9104 break;
9105 wsize = my->mc_wlen[toggle];
9106 ptr = my->mc_wbuf[toggle];
9107 again:
9108 rc = MDB_SUCCESS;
9109 while (wsize > 0 && !my->mc_error) {
9110 DO_WRITE(rc, my->mc_fd, ptr, wsize, len);
9111 if (!rc) {
9112 rc = ErrCode();
9113 #if defined(SIGPIPE) && !defined(_WIN32)
9114 if (rc == EPIPE) {
9115 /* Collect the pending SIGPIPE, otherwise at least OS X
9116 * gives it to the process on thread-exit (ITS#8504).
9117 */
9118 int tmp;
9119 sigwait(&set, &tmp);
9120 }
9121 #endif
9122 break;
9123 } else if (len > 0) {
9124 rc = MDB_SUCCESS;
9125 ptr += len;
9126 wsize -= len;
9127 continue;
9128 } else {
9129 rc = EIO;
9130 break;
9131 }
9132 }
9133 if (rc) {
9134 my->mc_error = rc;
9135 }
9136 /* If there's an overflow page tail, write it too */
9137 if (my->mc_olen[toggle]) {
9138 wsize = my->mc_olen[toggle];
9139 ptr = my->mc_over[toggle];
9140 my->mc_olen[toggle] = 0;
9141 goto again;
9142 }
9143 my->mc_wlen[toggle] = 0;
9144 toggle ^= 1;
9145 /* Return the empty buffer to provider */
9146 my->mc_new--;
9147 pthread_cond_signal(&my->mc_cond);
9148 }
9149 pthread_mutex_unlock(&my->mc_mutex);
9150 return (THREAD_RET)0;
9151 #undef DO_WRITE
9152 }
9153
9154 /** Give buffer and/or #MDB_EOF to writer thread, await unused buffer.
9155 *
9156 * @param[in] my control structure.
9157 * @param[in] adjust (1 to hand off 1 buffer) | (MDB_EOF when ending).
9158 */
9159 static int ESECT
mdb_env_cthr_toggle(mdb_copy * my,int adjust)9160 mdb_env_cthr_toggle(mdb_copy *my, int adjust)
9161 {
9162 pthread_mutex_lock(&my->mc_mutex);
9163 my->mc_new += adjust;
9164 pthread_cond_signal(&my->mc_cond);
9165 while (my->mc_new & 2) /* both buffers in use */
9166 pthread_cond_wait(&my->mc_cond, &my->mc_mutex);
9167 pthread_mutex_unlock(&my->mc_mutex);
9168
9169 my->mc_toggle ^= (adjust & 1);
9170 /* Both threads reset mc_wlen, to be safe from threading errors */
9171 my->mc_wlen[my->mc_toggle] = 0;
9172 return my->mc_error;
9173 }
9174
9175 /** Depth-first tree traversal for compacting copy.
9176 * @param[in] my control structure.
9177 * @param[in,out] pg database root.
9178 * @param[in] flags includes #F_DUPDATA if it is a sorted-duplicate sub-DB.
9179 */
9180 static int ESECT
mdb_env_cwalk(mdb_copy * my,pgno_t * pg,int flags)9181 mdb_env_cwalk(mdb_copy *my, pgno_t *pg, int flags)
9182 {
9183 MDB_cursor mc = {0};
9184 MDB_node *ni;
9185 MDB_page *mo, *mp, *leaf;
9186 char *buf, *ptr;
9187 int rc, toggle;
9188 unsigned int i;
9189
9190 /* Empty DB, nothing to do */
9191 if (*pg == P_INVALID)
9192 return MDB_SUCCESS;
9193
9194 mc.mc_snum = 1;
9195 mc.mc_txn = my->mc_txn;
9196
9197 rc = mdb_page_get(&mc, *pg, &mc.mc_pg[0], NULL);
9198 if (rc)
9199 return rc;
9200 rc = mdb_page_search_root(&mc, NULL, MDB_PS_FIRST);
9201 if (rc)
9202 return rc;
9203
9204 /* Make cursor pages writable */
9205 buf = ptr = malloc(my->mc_env->me_psize * mc.mc_snum);
9206 if (buf == NULL)
9207 return ENOMEM;
9208
9209 for (i=0; i<mc.mc_top; i++) {
9210 mdb_page_copy((MDB_page *)ptr, mc.mc_pg[i], my->mc_env->me_psize);
9211 mc.mc_pg[i] = (MDB_page *)ptr;
9212 ptr += my->mc_env->me_psize;
9213 }
9214
9215 /* This is writable space for a leaf page. Usually not needed. */
9216 leaf = (MDB_page *)ptr;
9217
9218 toggle = my->mc_toggle;
9219 while (mc.mc_snum > 0) {
9220 unsigned n;
9221 mp = mc.mc_pg[mc.mc_top];
9222 n = NUMKEYS(mp);
9223
9224 if (IS_LEAF(mp)) {
9225 if (!IS_LEAF2(mp) && !(flags & F_DUPDATA)) {
9226 for (i=0; i<n; i++) {
9227 ni = NODEPTR(mp, i);
9228 if (ni->mn_flags & F_BIGDATA) {
9229 MDB_page *omp;
9230 pgno_t pg;
9231
9232 /* Need writable leaf */
9233 if (mp != leaf) {
9234 mc.mc_pg[mc.mc_top] = leaf;
9235 mdb_page_copy(leaf, mp, my->mc_env->me_psize);
9236 mp = leaf;
9237 ni = NODEPTR(mp, i);
9238 }
9239
9240 memcpy(&pg, NODEDATA(ni), sizeof(pg));
9241 memcpy(NODEDATA(ni), &my->mc_next_pgno, sizeof(pgno_t));
9242 rc = mdb_page_get(&mc, pg, &omp, NULL);
9243 if (rc)
9244 goto done;
9245 if (my->mc_wlen[toggle] >= MDB_WBUF) {
9246 rc = mdb_env_cthr_toggle(my, 1);
9247 if (rc)
9248 goto done;
9249 toggle = my->mc_toggle;
9250 }
9251 mo = (MDB_page *)(my->mc_wbuf[toggle] + my->mc_wlen[toggle]);
9252 memcpy(mo, omp, my->mc_env->me_psize);
9253 mo->mp_pgno = my->mc_next_pgno;
9254 my->mc_next_pgno += omp->mp_pages;
9255 my->mc_wlen[toggle] += my->mc_env->me_psize;
9256 if (omp->mp_pages > 1) {
9257 my->mc_olen[toggle] = my->mc_env->me_psize * (omp->mp_pages - 1);
9258 my->mc_over[toggle] = (char *)omp + my->mc_env->me_psize;
9259 rc = mdb_env_cthr_toggle(my, 1);
9260 if (rc)
9261 goto done;
9262 toggle = my->mc_toggle;
9263 }
9264 } else if (ni->mn_flags & F_SUBDATA) {
9265 MDB_db db;
9266
9267 /* Need writable leaf */
9268 if (mp != leaf) {
9269 mc.mc_pg[mc.mc_top] = leaf;
9270 mdb_page_copy(leaf, mp, my->mc_env->me_psize);
9271 mp = leaf;
9272 ni = NODEPTR(mp, i);
9273 }
9274
9275 memcpy(&db, NODEDATA(ni), sizeof(db));
9276 my->mc_toggle = toggle;
9277 rc = mdb_env_cwalk(my, &db.md_root, ni->mn_flags & F_DUPDATA);
9278 if (rc)
9279 goto done;
9280 toggle = my->mc_toggle;
9281 memcpy(NODEDATA(ni), &db, sizeof(db));
9282 }
9283 }
9284 }
9285 } else {
9286 mc.mc_ki[mc.mc_top]++;
9287 if (mc.mc_ki[mc.mc_top] < n) {
9288 pgno_t pg;
9289 again:
9290 ni = NODEPTR(mp, mc.mc_ki[mc.mc_top]);
9291 pg = NODEPGNO(ni);
9292 rc = mdb_page_get(&mc, pg, &mp, NULL);
9293 if (rc)
9294 goto done;
9295 mc.mc_top++;
9296 mc.mc_snum++;
9297 mc.mc_ki[mc.mc_top] = 0;
9298 if (IS_BRANCH(mp)) {
9299 /* Whenever we advance to a sibling branch page,
9300 * we must proceed all the way down to its first leaf.
9301 */
9302 mdb_page_copy(mc.mc_pg[mc.mc_top], mp, my->mc_env->me_psize);
9303 goto again;
9304 } else
9305 mc.mc_pg[mc.mc_top] = mp;
9306 continue;
9307 }
9308 }
9309 if (my->mc_wlen[toggle] >= MDB_WBUF) {
9310 rc = mdb_env_cthr_toggle(my, 1);
9311 if (rc)
9312 goto done;
9313 toggle = my->mc_toggle;
9314 }
9315 mo = (MDB_page *)(my->mc_wbuf[toggle] + my->mc_wlen[toggle]);
9316 mdb_page_copy(mo, mp, my->mc_env->me_psize);
9317 mo->mp_pgno = my->mc_next_pgno++;
9318 my->mc_wlen[toggle] += my->mc_env->me_psize;
9319 if (mc.mc_top) {
9320 /* Update parent if there is one */
9321 ni = NODEPTR(mc.mc_pg[mc.mc_top-1], mc.mc_ki[mc.mc_top-1]);
9322 SETPGNO(ni, mo->mp_pgno);
9323 mdb_cursor_pop(&mc);
9324 } else {
9325 /* Otherwise we're done */
9326 *pg = mo->mp_pgno;
9327 break;
9328 }
9329 }
9330 done:
9331 free(buf);
9332 return rc;
9333 }
9334
9335 /** Copy environment with compaction. */
9336 static int ESECT
mdb_env_copyfd1(MDB_env * env,HANDLE fd)9337 mdb_env_copyfd1(MDB_env *env, HANDLE fd)
9338 {
9339 MDB_meta *mm;
9340 MDB_page *mp;
9341 mdb_copy my = {0};
9342 MDB_txn *txn = NULL;
9343 pthread_t thr;
9344 pgno_t root, new_root;
9345 int rc = MDB_SUCCESS;
9346
9347 #ifdef _WIN32
9348 if (!(my.mc_mutex = CreateMutex(NULL, FALSE, NULL)) ||
9349 !(my.mc_cond = CreateEvent(NULL, FALSE, FALSE, NULL))) {
9350 rc = ErrCode();
9351 goto done;
9352 }
9353 my.mc_wbuf[0] = _aligned_malloc(MDB_WBUF*2, env->me_os_psize);
9354 if (my.mc_wbuf[0] == NULL) {
9355 /* _aligned_malloc() sets errno, but we use Windows error codes */
9356 rc = ERROR_NOT_ENOUGH_MEMORY;
9357 goto done;
9358 }
9359 #else
9360 if ((rc = pthread_mutex_init(&my.mc_mutex, NULL)) != 0)
9361 return rc;
9362 if ((rc = pthread_cond_init(&my.mc_cond, NULL)) != 0)
9363 goto done2;
9364 #ifdef HAVE_MEMALIGN
9365 my.mc_wbuf[0] = memalign(env->me_os_psize, MDB_WBUF*2);
9366 if (my.mc_wbuf[0] == NULL) {
9367 rc = errno;
9368 goto done;
9369 }
9370 #else
9371 {
9372 void *p;
9373 if ((rc = posix_memalign(&p, env->me_os_psize, MDB_WBUF*2)) != 0)
9374 goto done;
9375 my.mc_wbuf[0] = p;
9376 }
9377 #endif
9378 #endif
9379 memset(my.mc_wbuf[0], 0, MDB_WBUF*2);
9380 my.mc_wbuf[1] = my.mc_wbuf[0] + MDB_WBUF;
9381 my.mc_next_pgno = NUM_METAS;
9382 my.mc_env = env;
9383 my.mc_fd = fd;
9384 rc = THREAD_CREATE(thr, mdb_env_copythr, &my);
9385 if (rc)
9386 goto done;
9387
9388 rc = mdb_txn_begin(env, NULL, MDB_RDONLY, &txn);
9389 if (rc)
9390 goto finish;
9391
9392 mp = (MDB_page *)my.mc_wbuf[0];
9393 memset(mp, 0, NUM_METAS * env->me_psize);
9394 mp->mp_pgno = 0;
9395 mp->mp_flags = P_META;
9396 mm = (MDB_meta *)METADATA(mp);
9397 mdb_env_init_meta0(env, mm);
9398 mm->mm_address = env->me_metas[0]->mm_address;
9399
9400 mp = (MDB_page *)(my.mc_wbuf[0] + env->me_psize);
9401 mp->mp_pgno = 1;
9402 mp->mp_flags = P_META;
9403 *(MDB_meta *)METADATA(mp) = *mm;
9404 mm = (MDB_meta *)METADATA(mp);
9405
9406 /* Set metapage 1 with current main DB */
9407 root = new_root = txn->mt_dbs[MAIN_DBI].md_root;
9408 if (root != P_INVALID) {
9409 /* Count free pages + freeDB pages. Subtract from last_pg
9410 * to find the new last_pg, which also becomes the new root.
9411 */
9412 MDB_ID freecount = 0;
9413 MDB_cursor mc;
9414 MDB_val key, data;
9415 mdb_cursor_init(&mc, txn, FREE_DBI, NULL);
9416 while ((rc = mdb_cursor_get(&mc, &key, &data, MDB_NEXT)) == 0)
9417 freecount += *(MDB_ID *)data.mv_data;
9418 if (rc != MDB_NOTFOUND)
9419 goto finish;
9420 freecount += txn->mt_dbs[FREE_DBI].md_branch_pages +
9421 txn->mt_dbs[FREE_DBI].md_leaf_pages +
9422 txn->mt_dbs[FREE_DBI].md_overflow_pages;
9423
9424 new_root = txn->mt_next_pgno - 1 - freecount;
9425 mm->mm_last_pg = new_root;
9426 mm->mm_dbs[MAIN_DBI] = txn->mt_dbs[MAIN_DBI];
9427 mm->mm_dbs[MAIN_DBI].md_root = new_root;
9428 } else {
9429 /* When the DB is empty, handle it specially to
9430 * fix any breakage like page leaks from ITS#8174.
9431 */
9432 mm->mm_dbs[MAIN_DBI].md_flags = txn->mt_dbs[MAIN_DBI].md_flags;
9433 }
9434 if (root != P_INVALID || mm->mm_dbs[MAIN_DBI].md_flags) {
9435 mm->mm_txnid = 1; /* use metapage 1 */
9436 }
9437
9438 my.mc_wlen[0] = env->me_psize * NUM_METAS;
9439 my.mc_txn = txn;
9440 rc = mdb_env_cwalk(&my, &root, 0);
9441 if (rc == MDB_SUCCESS && root != new_root) {
9442 rc = MDB_INCOMPATIBLE; /* page leak or corrupt DB */
9443 }
9444
9445 finish:
9446 if (rc)
9447 my.mc_error = rc;
9448 mdb_env_cthr_toggle(&my, 1 | MDB_EOF);
9449 rc = THREAD_FINISH(thr);
9450 mdb_txn_abort(txn);
9451
9452 done:
9453 #ifdef _WIN32
9454 if (my.mc_wbuf[0]) _aligned_free(my.mc_wbuf[0]);
9455 if (my.mc_cond) CloseHandle(my.mc_cond);
9456 if (my.mc_mutex) CloseHandle(my.mc_mutex);
9457 #else
9458 free(my.mc_wbuf[0]);
9459 pthread_cond_destroy(&my.mc_cond);
9460 done2:
9461 pthread_mutex_destroy(&my.mc_mutex);
9462 #endif
9463 return rc ? rc : my.mc_error;
9464 }
9465
9466 /** Copy environment as-is. */
9467 static int ESECT
mdb_env_copyfd0(MDB_env * env,HANDLE fd)9468 mdb_env_copyfd0(MDB_env *env, HANDLE fd)
9469 {
9470 MDB_txn *txn = NULL;
9471 mdb_mutexref_t wmutex = NULL;
9472 int rc;
9473 size_t wsize, w3;
9474 char *ptr;
9475 #ifdef _WIN32
9476 DWORD len, w2;
9477 #define DO_WRITE(rc, fd, ptr, w2, len) rc = WriteFile(fd, ptr, w2, &len, NULL)
9478 #else
9479 ssize_t len;
9480 size_t w2;
9481 #define DO_WRITE(rc, fd, ptr, w2, len) len = write(fd, ptr, w2); rc = (len >= 0)
9482 #endif
9483
9484 /* Do the lock/unlock of the reader mutex before starting the
9485 * write txn. Otherwise other read txns could block writers.
9486 */
9487 rc = mdb_txn_begin(env, NULL, MDB_RDONLY, &txn);
9488 if (rc)
9489 return rc;
9490
9491 if (env->me_txns) {
9492 /* We must start the actual read txn after blocking writers */
9493 mdb_txn_end(txn, MDB_END_RESET_TMP);
9494
9495 /* Temporarily block writers until we snapshot the meta pages */
9496 wmutex = env->me_wmutex;
9497 if (LOCK_MUTEX(rc, env, wmutex))
9498 goto leave;
9499
9500 rc = mdb_txn_renew0(txn);
9501 if (rc) {
9502 UNLOCK_MUTEX(wmutex);
9503 goto leave;
9504 }
9505 }
9506
9507 wsize = env->me_psize * NUM_METAS;
9508 ptr = env->me_map;
9509 w2 = wsize;
9510 while (w2 > 0) {
9511 DO_WRITE(rc, fd, ptr, w2, len);
9512 if (!rc) {
9513 rc = ErrCode();
9514 break;
9515 } else if (len > 0) {
9516 rc = MDB_SUCCESS;
9517 ptr += len;
9518 w2 -= len;
9519 continue;
9520 } else {
9521 /* Non-blocking or async handles are not supported */
9522 rc = EIO;
9523 break;
9524 }
9525 }
9526 if (wmutex)
9527 UNLOCK_MUTEX(wmutex);
9528
9529 if (rc)
9530 goto leave;
9531
9532 w3 = txn->mt_next_pgno * env->me_psize;
9533 {
9534 size_t fsize = 0;
9535 if ((rc = mdb_fsize(env->me_fd, &fsize)))
9536 goto leave;
9537 if (w3 > fsize)
9538 w3 = fsize;
9539 }
9540 wsize = w3 - wsize;
9541 while (wsize > 0) {
9542 if (wsize > MAX_WRITE)
9543 w2 = MAX_WRITE;
9544 else
9545 w2 = wsize;
9546 DO_WRITE(rc, fd, ptr, w2, len);
9547 if (!rc) {
9548 rc = ErrCode();
9549 break;
9550 } else if (len > 0) {
9551 rc = MDB_SUCCESS;
9552 ptr += len;
9553 wsize -= len;
9554 continue;
9555 } else {
9556 rc = EIO;
9557 break;
9558 }
9559 }
9560
9561 leave:
9562 mdb_txn_abort(txn);
9563 return rc;
9564 }
9565
9566 int ESECT
mdb_env_copyfd2(MDB_env * env,HANDLE fd,unsigned int flags)9567 mdb_env_copyfd2(MDB_env *env, HANDLE fd, unsigned int flags)
9568 {
9569 if (flags & MDB_CP_COMPACT)
9570 return mdb_env_copyfd1(env, fd);
9571 else
9572 return mdb_env_copyfd0(env, fd);
9573 }
9574
9575 int ESECT
mdb_env_copyfd(MDB_env * env,HANDLE fd)9576 mdb_env_copyfd(MDB_env *env, HANDLE fd)
9577 {
9578 return mdb_env_copyfd2(env, fd, 0);
9579 }
9580
9581 int ESECT
mdb_env_copy2(MDB_env * env,const char * path,unsigned int flags)9582 mdb_env_copy2(MDB_env *env, const char *path, unsigned int flags)
9583 {
9584 int rc;
9585 MDB_name fname;
9586 HANDLE newfd = INVALID_HANDLE_VALUE;
9587
9588 rc = mdb_fname_init(path, env->me_flags | MDB_NOLOCK, &fname);
9589 if (rc == MDB_SUCCESS) {
9590 rc = mdb_fopen(env, &fname, MDB_O_COPY, 0666, &newfd);
9591 mdb_fname_destroy(fname);
9592 }
9593 if (rc == MDB_SUCCESS) {
9594 rc = mdb_env_copyfd2(env, newfd, flags);
9595 if (close(newfd) < 0 && rc == MDB_SUCCESS)
9596 rc = ErrCode();
9597 }
9598 return rc;
9599 }
9600
9601 int ESECT
mdb_env_copy(MDB_env * env,const char * path)9602 mdb_env_copy(MDB_env *env, const char *path)
9603 {
9604 return mdb_env_copy2(env, path, 0);
9605 }
9606
9607 int ESECT
mdb_env_set_flags(MDB_env * env,unsigned int flag,int onoff)9608 mdb_env_set_flags(MDB_env *env, unsigned int flag, int onoff)
9609 {
9610 if (flag & ~CHANGEABLE)
9611 return EINVAL;
9612 if (onoff)
9613 env->me_flags |= flag;
9614 else
9615 env->me_flags &= ~flag;
9616 return MDB_SUCCESS;
9617 }
9618
9619 int ESECT
mdb_env_get_flags(MDB_env * env,unsigned int * arg)9620 mdb_env_get_flags(MDB_env *env, unsigned int *arg)
9621 {
9622 if (!env || !arg)
9623 return EINVAL;
9624
9625 *arg = env->me_flags & (CHANGEABLE|CHANGELESS);
9626 return MDB_SUCCESS;
9627 }
9628
9629 int ESECT
mdb_env_set_userctx(MDB_env * env,void * ctx)9630 mdb_env_set_userctx(MDB_env *env, void *ctx)
9631 {
9632 if (!env)
9633 return EINVAL;
9634 env->me_userctx = ctx;
9635 return MDB_SUCCESS;
9636 }
9637
9638 void * ESECT
mdb_env_get_userctx(MDB_env * env)9639 mdb_env_get_userctx(MDB_env *env)
9640 {
9641 return env ? env->me_userctx : NULL;
9642 }
9643
9644 int ESECT
mdb_env_set_assert(MDB_env * env,MDB_assert_func * func)9645 mdb_env_set_assert(MDB_env *env, MDB_assert_func *func)
9646 {
9647 if (!env)
9648 return EINVAL;
9649 #ifndef NDEBUG
9650 env->me_assert_func = func;
9651 #endif
9652 return MDB_SUCCESS;
9653 }
9654
9655 int ESECT
mdb_env_get_path(MDB_env * env,const char ** arg)9656 mdb_env_get_path(MDB_env *env, const char **arg)
9657 {
9658 if (!env || !arg)
9659 return EINVAL;
9660
9661 *arg = env->me_path;
9662 return MDB_SUCCESS;
9663 }
9664
9665 int ESECT
mdb_env_get_fd(MDB_env * env,mdb_filehandle_t * arg)9666 mdb_env_get_fd(MDB_env *env, mdb_filehandle_t *arg)
9667 {
9668 if (!env || !arg)
9669 return EINVAL;
9670
9671 *arg = env->me_fd;
9672 return MDB_SUCCESS;
9673 }
9674
9675 /** Common code for #mdb_stat() and #mdb_env_stat().
9676 * @param[in] env the environment to operate in.
9677 * @param[in] db the #MDB_db record containing the stats to return.
9678 * @param[out] arg the address of an #MDB_stat structure to receive the stats.
9679 * @return 0, this function always succeeds.
9680 */
9681 static int ESECT
mdb_stat0(MDB_env * env,MDB_db * db,MDB_stat * arg)9682 mdb_stat0(MDB_env *env, MDB_db *db, MDB_stat *arg)
9683 {
9684 arg->ms_psize = env->me_psize;
9685 arg->ms_depth = db->md_depth;
9686 arg->ms_branch_pages = db->md_branch_pages;
9687 arg->ms_leaf_pages = db->md_leaf_pages;
9688 arg->ms_overflow_pages = db->md_overflow_pages;
9689 arg->ms_entries = db->md_entries;
9690
9691 return MDB_SUCCESS;
9692 }
9693
9694 int ESECT
mdb_env_stat(MDB_env * env,MDB_stat * arg)9695 mdb_env_stat(MDB_env *env, MDB_stat *arg)
9696 {
9697 MDB_meta *meta;
9698
9699 if (env == NULL || arg == NULL)
9700 return EINVAL;
9701
9702 meta = mdb_env_pick_meta(env);
9703
9704 return mdb_stat0(env, &meta->mm_dbs[MAIN_DBI], arg);
9705 }
9706
9707 int ESECT
mdb_env_info(MDB_env * env,MDB_envinfo * arg)9708 mdb_env_info(MDB_env *env, MDB_envinfo *arg)
9709 {
9710 MDB_meta *meta;
9711
9712 if (env == NULL || arg == NULL)
9713 return EINVAL;
9714
9715 meta = mdb_env_pick_meta(env);
9716 arg->me_mapaddr = meta->mm_address;
9717 arg->me_last_pgno = meta->mm_last_pg;
9718 arg->me_last_txnid = meta->mm_txnid;
9719
9720 arg->me_mapsize = env->me_mapsize;
9721 arg->me_maxreaders = env->me_maxreaders;
9722 arg->me_numreaders = env->me_txns ? env->me_txns->mti_numreaders : 0;
9723 return MDB_SUCCESS;
9724 }
9725
9726 /** Set the default comparison functions for a database.
9727 * Called immediately after a database is opened to set the defaults.
9728 * The user can then override them with #mdb_set_compare() or
9729 * #mdb_set_dupsort().
9730 * @param[in] txn A transaction handle returned by #mdb_txn_begin()
9731 * @param[in] dbi A database handle returned by #mdb_dbi_open()
9732 */
9733 static void
mdb_default_cmp(MDB_txn * txn,MDB_dbi dbi)9734 mdb_default_cmp(MDB_txn *txn, MDB_dbi dbi)
9735 {
9736 uint16_t f = txn->mt_dbs[dbi].md_flags;
9737
9738 txn->mt_dbxs[dbi].md_cmp =
9739 (f & MDB_REVERSEKEY) ? mdb_cmp_memnr :
9740 (f & MDB_INTEGERKEY) ? mdb_cmp_cint : mdb_cmp_memn;
9741
9742 txn->mt_dbxs[dbi].md_dcmp =
9743 !(f & MDB_DUPSORT) ? 0 :
9744 ((f & MDB_INTEGERDUP)
9745 ? ((f & MDB_DUPFIXED) ? mdb_cmp_int : mdb_cmp_cint)
9746 : ((f & MDB_REVERSEDUP) ? mdb_cmp_memnr : mdb_cmp_memn));
9747 }
9748
mdb_dbi_open(MDB_txn * txn,const char * name,unsigned int flags,MDB_dbi * dbi)9749 int mdb_dbi_open(MDB_txn *txn, const char *name, unsigned int flags, MDB_dbi *dbi)
9750 {
9751 MDB_val key, data;
9752 MDB_dbi i;
9753 MDB_cursor mc;
9754 MDB_db dummy;
9755 int rc, dbflag, exact;
9756 unsigned int unused = 0, seq;
9757 char *namedup;
9758 size_t len;
9759
9760 if (flags & ~VALID_FLAGS)
9761 return EINVAL;
9762 if (txn->mt_flags & MDB_TXN_BLOCKED)
9763 return MDB_BAD_TXN;
9764
9765 /* main DB? */
9766 if (!name) {
9767 *dbi = MAIN_DBI;
9768 if (flags & PERSISTENT_FLAGS) {
9769 uint16_t f2 = flags & PERSISTENT_FLAGS;
9770 /* make sure flag changes get committed */
9771 if ((txn->mt_dbs[MAIN_DBI].md_flags | f2) != txn->mt_dbs[MAIN_DBI].md_flags) {
9772 txn->mt_dbs[MAIN_DBI].md_flags |= f2;
9773 txn->mt_flags |= MDB_TXN_DIRTY;
9774 }
9775 }
9776 mdb_default_cmp(txn, MAIN_DBI);
9777 return MDB_SUCCESS;
9778 }
9779
9780 if (txn->mt_dbxs[MAIN_DBI].md_cmp == NULL) {
9781 mdb_default_cmp(txn, MAIN_DBI);
9782 }
9783
9784 /* Is the DB already open? */
9785 len = strlen(name);
9786 for (i=CORE_DBS; i<txn->mt_numdbs; i++) {
9787 if (!txn->mt_dbxs[i].md_name.mv_size) {
9788 /* Remember this free slot */
9789 if (!unused) unused = i;
9790 continue;
9791 }
9792 if (len == txn->mt_dbxs[i].md_name.mv_size &&
9793 !strncmp(name, txn->mt_dbxs[i].md_name.mv_data, len)) {
9794 *dbi = i;
9795 return MDB_SUCCESS;
9796 }
9797 }
9798
9799 /* If no free slot and max hit, fail */
9800 if (!unused && txn->mt_numdbs >= txn->mt_env->me_maxdbs)
9801 return MDB_DBS_FULL;
9802
9803 /* Cannot mix named databases with some mainDB flags */
9804 if (txn->mt_dbs[MAIN_DBI].md_flags & (MDB_DUPSORT|MDB_INTEGERKEY))
9805 return (flags & MDB_CREATE) ? MDB_INCOMPATIBLE : MDB_NOTFOUND;
9806
9807 /* Find the DB info */
9808 dbflag = DB_NEW|DB_VALID|DB_USRVALID;
9809 exact = 0;
9810 key.mv_size = len;
9811 key.mv_data = (void *)name;
9812 mdb_cursor_init(&mc, txn, MAIN_DBI, NULL);
9813 rc = mdb_cursor_set(&mc, &key, &data, MDB_SET, &exact);
9814 if (rc == MDB_SUCCESS) {
9815 /* make sure this is actually a DB */
9816 MDB_node *node = NODEPTR(mc.mc_pg[mc.mc_top], mc.mc_ki[mc.mc_top]);
9817 if ((node->mn_flags & (F_DUPDATA|F_SUBDATA)) != F_SUBDATA)
9818 return MDB_INCOMPATIBLE;
9819 } else {
9820 if (rc != MDB_NOTFOUND || !(flags & MDB_CREATE))
9821 return rc;
9822 if (F_ISSET(txn->mt_flags, MDB_TXN_RDONLY))
9823 return EACCES;
9824 }
9825
9826 /* Done here so we cannot fail after creating a new DB */
9827 if ((namedup = strdup(name)) == NULL)
9828 return ENOMEM;
9829
9830 if (rc) {
9831 /* MDB_NOTFOUND and MDB_CREATE: Create new DB */
9832 data.mv_size = sizeof(MDB_db);
9833 data.mv_data = &dummy;
9834 memset(&dummy, 0, sizeof(dummy));
9835 dummy.md_root = P_INVALID;
9836 dummy.md_flags = flags & PERSISTENT_FLAGS;
9837 WITH_CURSOR_TRACKING(mc,
9838 rc = mdb_cursor_put(&mc, &key, &data, F_SUBDATA));
9839 dbflag |= DB_DIRTY;
9840 }
9841
9842 if (rc) {
9843 free(namedup);
9844 } else {
9845 /* Got info, register DBI in this txn */
9846 unsigned int slot = unused ? unused : txn->mt_numdbs;
9847 txn->mt_dbxs[slot].md_name.mv_data = namedup;
9848 txn->mt_dbxs[slot].md_name.mv_size = len;
9849 txn->mt_dbxs[slot].md_rel = NULL;
9850 txn->mt_dbflags[slot] = dbflag;
9851 /* txn-> and env-> are the same in read txns, use
9852 * tmp variable to avoid undefined assignment
9853 */
9854 seq = ++txn->mt_env->me_dbiseqs[slot];
9855 txn->mt_dbiseqs[slot] = seq;
9856
9857 memcpy(&txn->mt_dbs[slot], data.mv_data, sizeof(MDB_db));
9858 *dbi = slot;
9859 mdb_default_cmp(txn, slot);
9860 if (!unused) {
9861 txn->mt_numdbs++;
9862 }
9863 }
9864
9865 return rc;
9866 }
9867
9868 int ESECT
mdb_stat(MDB_txn * txn,MDB_dbi dbi,MDB_stat * arg)9869 mdb_stat(MDB_txn *txn, MDB_dbi dbi, MDB_stat *arg)
9870 {
9871 if (!arg || !TXN_DBI_EXIST(txn, dbi, DB_VALID))
9872 return EINVAL;
9873
9874 if (txn->mt_flags & MDB_TXN_BLOCKED)
9875 return MDB_BAD_TXN;
9876
9877 if (txn->mt_dbflags[dbi] & DB_STALE) {
9878 MDB_cursor mc;
9879 MDB_xcursor mx;
9880 /* Stale, must read the DB's root. cursor_init does it for us. */
9881 mdb_cursor_init(&mc, txn, dbi, &mx);
9882 }
9883 return mdb_stat0(txn->mt_env, &txn->mt_dbs[dbi], arg);
9884 }
9885
mdb_dbi_close(MDB_env * env,MDB_dbi dbi)9886 void mdb_dbi_close(MDB_env *env, MDB_dbi dbi)
9887 {
9888 char *ptr;
9889 if (dbi < CORE_DBS || dbi >= env->me_maxdbs)
9890 return;
9891 ptr = env->me_dbxs[dbi].md_name.mv_data;
9892 /* If there was no name, this was already closed */
9893 if (ptr) {
9894 env->me_dbxs[dbi].md_name.mv_data = NULL;
9895 env->me_dbxs[dbi].md_name.mv_size = 0;
9896 env->me_dbflags[dbi] = 0;
9897 env->me_dbiseqs[dbi]++;
9898 free(ptr);
9899 }
9900 }
9901
mdb_dbi_flags(MDB_txn * txn,MDB_dbi dbi,unsigned int * flags)9902 int mdb_dbi_flags(MDB_txn *txn, MDB_dbi dbi, unsigned int *flags)
9903 {
9904 /* We could return the flags for the FREE_DBI too but what's the point? */
9905 if (!TXN_DBI_EXIST(txn, dbi, DB_USRVALID))
9906 return EINVAL;
9907 *flags = txn->mt_dbs[dbi].md_flags & PERSISTENT_FLAGS;
9908 return MDB_SUCCESS;
9909 }
9910
9911 /** Add all the DB's pages to the free list.
9912 * @param[in] mc Cursor on the DB to free.
9913 * @param[in] subs non-Zero to check for sub-DBs in this DB.
9914 * @return 0 on success, non-zero on failure.
9915 */
9916 static int
mdb_drop0(MDB_cursor * mc,int subs)9917 mdb_drop0(MDB_cursor *mc, int subs)
9918 {
9919 int rc;
9920
9921 rc = mdb_page_search(mc, NULL, MDB_PS_FIRST);
9922 if (rc == MDB_SUCCESS) {
9923 MDB_txn *txn = mc->mc_txn;
9924 MDB_node *ni;
9925 MDB_cursor mx;
9926 unsigned int i;
9927
9928 /* DUPSORT sub-DBs have no ovpages/DBs. Omit scanning leaves.
9929 * This also avoids any P_LEAF2 pages, which have no nodes.
9930 * Also if the DB doesn't have sub-DBs and has no overflow
9931 * pages, omit scanning leaves.
9932 */
9933 if ((mc->mc_flags & C_SUB) ||
9934 (!subs && !mc->mc_db->md_overflow_pages))
9935 mdb_cursor_pop(mc);
9936
9937 mdb_cursor_copy(mc, &mx);
9938 while (mc->mc_snum > 0) {
9939 MDB_page *mp = mc->mc_pg[mc->mc_top];
9940 unsigned n = NUMKEYS(mp);
9941 if (IS_LEAF(mp)) {
9942 for (i=0; i<n; i++) {
9943 ni = NODEPTR(mp, i);
9944 if (ni->mn_flags & F_BIGDATA) {
9945 MDB_page *omp;
9946 pgno_t pg;
9947 memcpy(&pg, NODEDATA(ni), sizeof(pg));
9948 rc = mdb_page_get(mc, pg, &omp, NULL);
9949 if (rc != 0)
9950 goto done;
9951 mdb_cassert(mc, IS_OVERFLOW(omp));
9952 rc = mdb_midl_append_range(&txn->mt_free_pgs,
9953 pg, omp->mp_pages);
9954 if (rc)
9955 goto done;
9956 mc->mc_db->md_overflow_pages -= omp->mp_pages;
9957 if (!mc->mc_db->md_overflow_pages && !subs)
9958 break;
9959 } else if (subs && (ni->mn_flags & F_SUBDATA)) {
9960 mdb_xcursor_init1(mc, ni);
9961 rc = mdb_drop0(&mc->mc_xcursor->mx_cursor, 0);
9962 if (rc)
9963 goto done;
9964 }
9965 }
9966 if (!subs && !mc->mc_db->md_overflow_pages)
9967 goto pop;
9968 } else {
9969 if ((rc = mdb_midl_need(&txn->mt_free_pgs, n)) != 0)
9970 goto done;
9971 for (i=0; i<n; i++) {
9972 pgno_t pg;
9973 ni = NODEPTR(mp, i);
9974 pg = NODEPGNO(ni);
9975 /* free it */
9976 mdb_midl_xappend(txn->mt_free_pgs, pg);
9977 }
9978 }
9979 if (!mc->mc_top)
9980 break;
9981 mc->mc_ki[mc->mc_top] = i;
9982 rc = mdb_cursor_sibling(mc, 1);
9983 if (rc) {
9984 if (rc != MDB_NOTFOUND)
9985 goto done;
9986 /* no more siblings, go back to beginning
9987 * of previous level.
9988 */
9989 pop:
9990 mdb_cursor_pop(mc);
9991 mc->mc_ki[0] = 0;
9992 for (i=1; i<mc->mc_snum; i++) {
9993 mc->mc_ki[i] = 0;
9994 mc->mc_pg[i] = mx.mc_pg[i];
9995 }
9996 }
9997 }
9998 /* free it */
9999 rc = mdb_midl_append(&txn->mt_free_pgs, mc->mc_db->md_root);
10000 done:
10001 if (rc)
10002 txn->mt_flags |= MDB_TXN_ERROR;
10003 } else if (rc == MDB_NOTFOUND) {
10004 rc = MDB_SUCCESS;
10005 }
10006 mc->mc_flags &= ~C_INITIALIZED;
10007 return rc;
10008 }
10009
mdb_drop(MDB_txn * txn,MDB_dbi dbi,int del)10010 int mdb_drop(MDB_txn *txn, MDB_dbi dbi, int del)
10011 {
10012 MDB_cursor *mc, *m2;
10013 int rc;
10014
10015 if ((unsigned)del > 1 || !TXN_DBI_EXIST(txn, dbi, DB_USRVALID))
10016 return EINVAL;
10017
10018 if (F_ISSET(txn->mt_flags, MDB_TXN_RDONLY))
10019 return EACCES;
10020
10021 if (TXN_DBI_CHANGED(txn, dbi))
10022 return MDB_BAD_DBI;
10023
10024 rc = mdb_cursor_open(txn, dbi, &mc);
10025 if (rc)
10026 return rc;
10027
10028 rc = mdb_drop0(mc, mc->mc_db->md_flags & MDB_DUPSORT);
10029 /* Invalidate the dropped DB's cursors */
10030 for (m2 = txn->mt_cursors[dbi]; m2; m2 = m2->mc_next)
10031 m2->mc_flags &= ~(C_INITIALIZED|C_EOF);
10032 if (rc)
10033 goto leave;
10034
10035 /* Can't delete the main DB */
10036 if (del && dbi >= CORE_DBS) {
10037 rc = mdb_del0(txn, MAIN_DBI, &mc->mc_dbx->md_name, NULL, F_SUBDATA);
10038 if (!rc) {
10039 txn->mt_dbflags[dbi] = DB_STALE;
10040 mdb_dbi_close(txn->mt_env, dbi);
10041 } else {
10042 txn->mt_flags |= MDB_TXN_ERROR;
10043 }
10044 } else {
10045 /* reset the DB record, mark it dirty */
10046 txn->mt_dbflags[dbi] |= DB_DIRTY;
10047 txn->mt_dbs[dbi].md_depth = 0;
10048 txn->mt_dbs[dbi].md_branch_pages = 0;
10049 txn->mt_dbs[dbi].md_leaf_pages = 0;
10050 txn->mt_dbs[dbi].md_overflow_pages = 0;
10051 txn->mt_dbs[dbi].md_entries = 0;
10052 txn->mt_dbs[dbi].md_root = P_INVALID;
10053
10054 txn->mt_flags |= MDB_TXN_DIRTY;
10055 }
10056 leave:
10057 mdb_cursor_close(mc);
10058 return rc;
10059 }
10060
mdb_set_compare(MDB_txn * txn,MDB_dbi dbi,MDB_cmp_func * cmp)10061 int mdb_set_compare(MDB_txn *txn, MDB_dbi dbi, MDB_cmp_func *cmp)
10062 {
10063 if (!TXN_DBI_EXIST(txn, dbi, DB_USRVALID))
10064 return EINVAL;
10065
10066 txn->mt_dbxs[dbi].md_cmp = cmp;
10067 return MDB_SUCCESS;
10068 }
10069
mdb_set_dupsort(MDB_txn * txn,MDB_dbi dbi,MDB_cmp_func * cmp)10070 int mdb_set_dupsort(MDB_txn *txn, MDB_dbi dbi, MDB_cmp_func *cmp)
10071 {
10072 if (!TXN_DBI_EXIST(txn, dbi, DB_USRVALID))
10073 return EINVAL;
10074
10075 txn->mt_dbxs[dbi].md_dcmp = cmp;
10076 return MDB_SUCCESS;
10077 }
10078
mdb_set_relfunc(MDB_txn * txn,MDB_dbi dbi,MDB_rel_func * rel)10079 int mdb_set_relfunc(MDB_txn *txn, MDB_dbi dbi, MDB_rel_func *rel)
10080 {
10081 if (!TXN_DBI_EXIST(txn, dbi, DB_USRVALID))
10082 return EINVAL;
10083
10084 txn->mt_dbxs[dbi].md_rel = rel;
10085 return MDB_SUCCESS;
10086 }
10087
mdb_set_relctx(MDB_txn * txn,MDB_dbi dbi,void * ctx)10088 int mdb_set_relctx(MDB_txn *txn, MDB_dbi dbi, void *ctx)
10089 {
10090 if (!TXN_DBI_EXIST(txn, dbi, DB_USRVALID))
10091 return EINVAL;
10092
10093 txn->mt_dbxs[dbi].md_relctx = ctx;
10094 return MDB_SUCCESS;
10095 }
10096
10097 int ESECT
mdb_env_get_maxkeysize(MDB_env * env)10098 mdb_env_get_maxkeysize(MDB_env *env)
10099 {
10100 return ENV_MAXKEY(env);
10101 }
10102
10103 int ESECT
mdb_reader_list(MDB_env * env,MDB_msg_func * func,void * ctx)10104 mdb_reader_list(MDB_env *env, MDB_msg_func *func, void *ctx)
10105 {
10106 unsigned int i, rdrs;
10107 MDB_reader *mr;
10108 char buf[64];
10109 int rc = 0, first = 1;
10110
10111 if (!env || !func)
10112 return -1;
10113 if (!env->me_txns) {
10114 return func("(no reader locks)\n", ctx);
10115 }
10116 rdrs = env->me_txns->mti_numreaders;
10117 mr = env->me_txns->mti_readers;
10118 for (i=0; i<rdrs; i++) {
10119 if (mr[i].mr_pid) {
10120 txnid_t txnid = mr[i].mr_txnid;
10121 sprintf(buf, txnid == (txnid_t)-1 ?
10122 "%10d %"Z"x -\n" : "%10d %"Z"x %"Z"u\n",
10123 (int)mr[i].mr_pid, (size_t)mr[i].mr_tid, txnid);
10124 if (first) {
10125 first = 0;
10126 rc = func(" pid thread txnid\n", ctx);
10127 if (rc < 0)
10128 break;
10129 }
10130 rc = func(buf, ctx);
10131 if (rc < 0)
10132 break;
10133 }
10134 }
10135 if (first) {
10136 rc = func("(no active readers)\n", ctx);
10137 }
10138 return rc;
10139 }
10140
10141 /** Insert pid into list if not already present.
10142 * return -1 if already present.
10143 */
10144 static int ESECT
mdb_pid_insert(MDB_PID_T * ids,MDB_PID_T pid)10145 mdb_pid_insert(MDB_PID_T *ids, MDB_PID_T pid)
10146 {
10147 /* binary search of pid in list */
10148 unsigned base = 0;
10149 unsigned cursor = 1;
10150 int val = 0;
10151 unsigned n = ids[0];
10152
10153 while( 0 < n ) {
10154 unsigned pivot = n >> 1;
10155 cursor = base + pivot + 1;
10156 val = pid - ids[cursor];
10157
10158 if( val < 0 ) {
10159 n = pivot;
10160
10161 } else if ( val > 0 ) {
10162 base = cursor;
10163 n -= pivot + 1;
10164
10165 } else {
10166 /* found, so it's a duplicate */
10167 return -1;
10168 }
10169 }
10170
10171 if( val > 0 ) {
10172 ++cursor;
10173 }
10174 ids[0]++;
10175 for (n = ids[0]; n > cursor; n--)
10176 ids[n] = ids[n-1];
10177 ids[n] = pid;
10178 return 0;
10179 }
10180
10181 int ESECT
mdb_reader_check(MDB_env * env,int * dead)10182 mdb_reader_check(MDB_env *env, int *dead)
10183 {
10184 if (!env)
10185 return EINVAL;
10186 if (dead)
10187 *dead = 0;
10188 return env->me_txns ? mdb_reader_check0(env, 0, dead) : MDB_SUCCESS;
10189 }
10190
10191 /** As #mdb_reader_check(). \b rlocked is set if caller locked #me_rmutex. */
10192 static int ESECT
mdb_reader_check0(MDB_env * env,int rlocked,int * dead)10193 mdb_reader_check0(MDB_env *env, int rlocked, int *dead)
10194 {
10195 mdb_mutexref_t rmutex = rlocked ? NULL : env->me_rmutex;
10196 unsigned int i, j, rdrs;
10197 MDB_reader *mr;
10198 MDB_PID_T *pids, pid;
10199 int rc = MDB_SUCCESS, count = 0;
10200
10201 rdrs = env->me_txns->mti_numreaders;
10202 pids = malloc((rdrs+1) * sizeof(MDB_PID_T));
10203 if (!pids)
10204 return ENOMEM;
10205 pids[0] = 0;
10206 mr = env->me_txns->mti_readers;
10207 for (i=0; i<rdrs; i++) {
10208 pid = mr[i].mr_pid;
10209 if (pid && pid != env->me_pid) {
10210 if (mdb_pid_insert(pids, pid) == 0) {
10211 if (!mdb_reader_pid(env, Pidcheck, pid)) {
10212 /* Stale reader found */
10213 j = i;
10214 if (rmutex) {
10215 if ((rc = LOCK_MUTEX0(rmutex)) != 0) {
10216 if ((rc = mdb_mutex_failed(env, rmutex, rc)))
10217 break;
10218 rdrs = 0; /* the above checked all readers */
10219 } else {
10220 /* Recheck, a new process may have reused pid */
10221 if (mdb_reader_pid(env, Pidcheck, pid))
10222 j = rdrs;
10223 }
10224 }
10225 for (; j<rdrs; j++)
10226 if (mr[j].mr_pid == pid) {
10227 DPRINTF(("clear stale reader pid %u txn %"Z"d",
10228 (unsigned) pid, mr[j].mr_txnid));
10229 mr[j].mr_pid = 0;
10230 count++;
10231 }
10232 if (rmutex)
10233 UNLOCK_MUTEX(rmutex);
10234 }
10235 }
10236 }
10237 }
10238 free(pids);
10239 if (dead)
10240 *dead = count;
10241 return rc;
10242 }
10243
10244 #ifdef MDB_ROBUST_SUPPORTED
10245 /** Handle #LOCK_MUTEX0() failure.
10246 * Try to repair the lock file if the mutex owner died.
10247 * @param[in] env the environment handle
10248 * @param[in] mutex LOCK_MUTEX0() mutex
10249 * @param[in] rc LOCK_MUTEX0() error (nonzero)
10250 * @return 0 on success with the mutex locked, or an error code on failure.
10251 */
10252 static int ESECT
mdb_mutex_failed(MDB_env * env,mdb_mutexref_t mutex,int rc)10253 mdb_mutex_failed(MDB_env *env, mdb_mutexref_t mutex, int rc)
10254 {
10255 int rlocked, rc2;
10256 MDB_meta *meta;
10257
10258 if (rc == MDB_OWNERDEAD) {
10259 /* We own the mutex. Clean up after dead previous owner. */
10260 rc = MDB_SUCCESS;
10261 rlocked = (mutex == env->me_rmutex);
10262 if (!rlocked) {
10263 /* Keep mti_txnid updated, otherwise next writer can
10264 * overwrite data which latest meta page refers to.
10265 */
10266 meta = mdb_env_pick_meta(env);
10267 env->me_txns->mti_txnid = meta->mm_txnid;
10268 /* env is hosed if the dead thread was ours */
10269 if (env->me_txn) {
10270 env->me_flags |= MDB_FATAL_ERROR;
10271 env->me_txn = NULL;
10272 rc = MDB_PANIC;
10273 }
10274 }
10275 DPRINTF(("%cmutex owner died, %s", (rlocked ? 'r' : 'w'),
10276 (rc ? "this process' env is hosed" : "recovering")));
10277 rc2 = mdb_reader_check0(env, rlocked, NULL);
10278 if (rc2 == 0)
10279 rc2 = mdb_mutex_consistent(mutex);
10280 if (rc || (rc = rc2)) {
10281 DPRINTF(("LOCK_MUTEX recovery failed, %s", mdb_strerror(rc)));
10282 UNLOCK_MUTEX(mutex);
10283 }
10284 } else {
10285 #ifdef _WIN32
10286 rc = ErrCode();
10287 #endif
10288 DPRINTF(("LOCK_MUTEX failed, %s", mdb_strerror(rc)));
10289 }
10290
10291 return rc;
10292 }
10293 #endif /* MDB_ROBUST_SUPPORTED */
10294
10295 #if defined(_WIN32)
10296 /** Convert \b src to new wchar_t[] string with room for \b xtra extra chars */
10297 static int ESECT
utf8_to_utf16(const char * src,MDB_name * dst,int xtra)10298 utf8_to_utf16(const char *src, MDB_name *dst, int xtra)
10299 {
10300 int rc, need = 0;
10301 wchar_t *result = NULL;
10302 for (;;) { /* malloc result, then fill it in */
10303 need = MultiByteToWideChar(CP_UTF8, 0, src, -1, result, need);
10304 if (!need) {
10305 rc = ErrCode();
10306 free(result);
10307 return rc;
10308 }
10309 if (!result) {
10310 result = malloc(sizeof(wchar_t) * (need + xtra));
10311 if (!result)
10312 return ENOMEM;
10313 continue;
10314 }
10315 dst->mn_alloced = 1;
10316 dst->mn_len = need - 1;
10317 dst->mn_val = result;
10318 return MDB_SUCCESS;
10319 }
10320 }
10321 #endif /* defined(_WIN32) */
10322 /** @} */
10323