1 /* $NetBSD: hash.c,v 1.35 2015/06/22 21:16:02 christos Exp $ */
2
3 /*-
4 * Copyright (c) 1990, 1993, 1994
5 * The Regents of the University of California. All rights reserved.
6 *
7 * This code is derived from software contributed to Berkeley by
8 * Margo Seltzer.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35 #if HAVE_NBTOOL_CONFIG_H
36 #include "nbtool_config.h"
37 #endif
38
39 #include <sys/cdefs.h>
40 __RCSID("$NetBSD: hash.c,v 1.35 2015/06/22 21:16:02 christos Exp $");
41
42 #include "namespace.h"
43 #include <sys/param.h>
44 #include <sys/stat.h>
45
46 #include <errno.h>
47 #include <fcntl.h>
48 #include <stdio.h>
49 #include <stdlib.h>
50 #include <string.h>
51 #include <unistd.h>
52 #include <assert.h>
53
54 #include <db.h>
55 #include "hash.h"
56 #include "page.h"
57 #include "extern.h"
58
59 static int alloc_segs(HTAB *, int);
60 static int flush_meta(HTAB *);
61 static int hash_access(HTAB *, ACTION, DBT *, DBT *);
62 static int hash_close(DB *);
63 static int hash_delete(const DB *, const DBT *, uint32_t);
64 static int hash_fd(const DB *);
65 static int hash_get(const DB *, const DBT *, DBT *, uint32_t);
66 static int hash_put(const DB *, DBT *, const DBT *, uint32_t);
67 static void *hash_realloc(SEGMENT **, size_t, size_t);
68 static int hash_seq(const DB *, DBT *, DBT *, uint32_t);
69 static int hash_sync(const DB *, uint32_t);
70 static int hdestroy(HTAB *);
71 static HTAB *init_hash(HTAB *, const char *, const HASHINFO *);
72 static int init_htab(HTAB *, size_t);
73 #if BYTE_ORDER == LITTLE_ENDIAN
74 static void swap_header(HTAB *);
75 static void swap_header_copy(HASHHDR *, HASHHDR *);
76 #endif
77
78 /* Fast arithmetic, relying on powers of 2, */
79 #define MOD(x, y) ((x) & ((y) - 1))
80
81 #define RETURN_ERROR(ERR, LOC) { save_errno = ERR; goto LOC; }
82
83 /* Return values */
84 #define SUCCESS (0)
85 #define ERROR (-1)
86 #define ABNORMAL (1)
87
88 #ifdef HASH_STATISTICS
89 int hash_accesses, hash_collisions, hash_expansions, hash_overflows;
90 #endif
91
92 /************************** INTERFACE ROUTINES ***************************/
93 /* OPEN/CLOSE */
94
95 /* ARGSUSED */
96 DB *
__hash_open(const char * file,int flags,mode_t mode,const HASHINFO * info,int dflags)97 __hash_open(const char *file, int flags, mode_t mode, const HASHINFO *info,
98 int dflags)
99 {
100 HTAB *hashp;
101 struct stat statbuf;
102 DB *dbp;
103 int bpages, new_table, nsegs, save_errno;
104 ssize_t hdrsize;
105
106 if ((flags & O_ACCMODE) == O_WRONLY) {
107 errno = EINVAL;
108 return (NULL);
109 }
110
111 if (!(hashp = calloc(1, sizeof(HTAB))))
112 return (NULL);
113 hashp->fp = -1;
114
115 /*
116 * Even if user wants write only, we need to be able to read
117 * the actual file, so we need to open it read/write. But, the
118 * field in the hashp structure needs to be accurate so that
119 * we can check accesses.
120 */
121 hashp->flags = flags;
122
123 new_table = 0;
124 if (!file || (flags & O_TRUNC) ||
125 (stat(file, &statbuf) && (errno == ENOENT))) {
126 if (errno == ENOENT)
127 errno = 0; /* Just in case someone looks at errno */
128 new_table = 1;
129 }
130 if (file) {
131 if ((hashp->fp = __dbopen(file, flags, mode, &statbuf)) == -1)
132 RETURN_ERROR(errno, error0);
133 new_table |= statbuf.st_size == 0;
134 }
135 if (new_table) {
136 if (!(hashp = init_hash(hashp, file, info)))
137 RETURN_ERROR(errno, error1);
138 } else {
139 /* Table already exists */
140 if (info && info->hash)
141 hashp->hash = info->hash;
142 else
143 hashp->hash = __default_hash;
144
145 hdrsize = read(hashp->fp, &hashp->hdr, sizeof(HASHHDR));
146 #if BYTE_ORDER == LITTLE_ENDIAN
147 swap_header(hashp);
148 #endif
149 if (hdrsize == -1)
150 RETURN_ERROR(errno, error1);
151 if (hdrsize != sizeof(HASHHDR))
152 RETURN_ERROR(EFTYPE, error1);
153 /* Verify file type, versions and hash function */
154 if (hashp->MAGIC != HASHMAGIC)
155 RETURN_ERROR(EFTYPE, error1);
156 #define OLDHASHVERSION 1
157 if (hashp->VERSION != HASHVERSION &&
158 hashp->VERSION != OLDHASHVERSION)
159 RETURN_ERROR(EFTYPE, error1);
160 if (hashp->hash(CHARKEY, sizeof(CHARKEY)) !=
161 (uint32_t)hashp->H_CHARKEY)
162 RETURN_ERROR(EFTYPE, error1);
163 /*
164 * Figure out how many segments we need. Max_Bucket is the
165 * maximum bucket number, so the number of buckets is
166 * max_bucket + 1.
167 */
168 nsegs = (hashp->MAX_BUCKET + 1 + hashp->SGSIZE - 1) /
169 hashp->SGSIZE;
170 hashp->nsegs = 0;
171 if (alloc_segs(hashp, nsegs))
172 /*
173 * If alloc_segs fails, table will have been destroyed
174 * and errno will have been set.
175 */
176 return (NULL);
177 /* Read in bitmaps */
178 bpages = (hashp->SPARES[hashp->OVFL_POINT] +
179 (unsigned int)(hashp->BSIZE << BYTE_SHIFT) - 1) >>
180 (hashp->BSHIFT + BYTE_SHIFT);
181
182 hashp->nmaps = bpages;
183 (void)memset(&hashp->mapp[0], 0, bpages * sizeof(uint32_t *));
184 }
185
186 /* Initialize Buffer Manager */
187 if (info && info->cachesize)
188 __buf_init(hashp, info->cachesize);
189 else
190 __buf_init(hashp, DEF_BUFSIZE);
191
192 hashp->new_file = new_table;
193 hashp->save_file = file && (hashp->flags & O_RDWR);
194 hashp->cbucket = -1;
195 if (!(dbp = malloc(sizeof(*dbp)))) {
196 save_errno = errno;
197 hdestroy(hashp);
198 errno = save_errno;
199 return (NULL);
200 }
201 dbp->internal = hashp;
202 dbp->close = hash_close;
203 dbp->del = hash_delete;
204 dbp->fd = hash_fd;
205 dbp->get = hash_get;
206 dbp->put = hash_put;
207 dbp->seq = hash_seq;
208 dbp->sync = hash_sync;
209 dbp->type = DB_HASH;
210
211 #ifdef DEBUG1
212 (void)fprintf(stderr,
213 "%s\n%s%p\n%s%d\n%s%d\n%s%d\n%s%d\n%s%d\n%s%d\n%s%d\n%s%d\n%s%d\n%s%x\n%s%x\n%s%d\n%s%d\n",
214 "init_htab:",
215 "TABLE POINTER ", hashp,
216 "BUCKET SIZE ", hashp->BSIZE,
217 "BUCKET SHIFT ", hashp->BSHIFT,
218 "DIRECTORY SIZE ", hashp->DSIZE,
219 "SEGMENT SIZE ", hashp->SGSIZE,
220 "SEGMENT SHIFT ", hashp->SSHIFT,
221 "FILL FACTOR ", hashp->FFACTOR,
222 "MAX BUCKET ", hashp->MAX_BUCKET,
223 "OVFL POINT ", hashp->OVFL_POINT,
224 "LAST FREED ", hashp->LAST_FREED,
225 "HIGH MASK ", hashp->HIGH_MASK,
226 "LOW MASK ", hashp->LOW_MASK,
227 "NSEGS ", hashp->nsegs,
228 "NKEYS ", hashp->NKEYS);
229 #endif
230 #ifdef HASH_STATISTICS
231 hash_overflows = hash_accesses = hash_collisions = hash_expansions = 0;
232 #endif
233 return (dbp);
234
235 error1:
236 if (hashp != NULL)
237 (void)close(hashp->fp);
238
239 error0:
240 free(hashp);
241 errno = save_errno;
242 return (NULL);
243 }
244
245 static int
hash_close(DB * dbp)246 hash_close(DB *dbp)
247 {
248 HTAB *hashp;
249 int retval;
250
251 if (!dbp)
252 return (ERROR);
253
254 hashp = dbp->internal;
255 retval = hdestroy(hashp);
256 free(dbp);
257 return (retval);
258 }
259
260 static int
hash_fd(const DB * dbp)261 hash_fd(const DB *dbp)
262 {
263 HTAB *hashp;
264
265 if (!dbp)
266 return (ERROR);
267
268 hashp = dbp->internal;
269 if (hashp->fp == -1) {
270 errno = ENOENT;
271 return (-1);
272 }
273 return (hashp->fp);
274 }
275
276 /************************** LOCAL CREATION ROUTINES **********************/
277 static HTAB *
init_hash(HTAB * hashp,const char * file,const HASHINFO * info)278 init_hash(HTAB *hashp, const char *file, const HASHINFO *info)
279 {
280 struct stat statbuf;
281 int nelem;
282
283 nelem = 1;
284 hashp->NKEYS = 0;
285 hashp->LORDER = BYTE_ORDER;
286 hashp->BSIZE = DEF_BUCKET_SIZE;
287 hashp->BSHIFT = DEF_BUCKET_SHIFT;
288 hashp->SGSIZE = DEF_SEGSIZE;
289 hashp->SSHIFT = DEF_SEGSIZE_SHIFT;
290 hashp->DSIZE = DEF_DIRSIZE;
291 hashp->FFACTOR = DEF_FFACTOR;
292 hashp->hash = __default_hash;
293 memset(hashp->SPARES, 0, sizeof(hashp->SPARES));
294 memset(hashp->BITMAPS, 0, sizeof (hashp->BITMAPS));
295
296 /* Fix bucket size to be optimal for file system */
297 if (file != NULL) {
298 if (stat(file, &statbuf))
299 return (NULL);
300 hashp->BSIZE = MIN(statbuf.st_blksize, MAX_BSIZE);
301 hashp->BSHIFT = __log2((uint32_t)hashp->BSIZE);
302 }
303
304 if (info) {
305 if (info->bsize) {
306 /* Round pagesize up to power of 2 */
307 hashp->BSHIFT = __log2(info->bsize);
308 hashp->BSIZE = 1 << hashp->BSHIFT;
309 if (hashp->BSIZE > MAX_BSIZE) {
310 errno = EINVAL;
311 return (NULL);
312 }
313 }
314 if (info->ffactor)
315 hashp->FFACTOR = info->ffactor;
316 if (info->hash)
317 hashp->hash = info->hash;
318 if (info->nelem)
319 nelem = info->nelem;
320 if (info->lorder) {
321 if (info->lorder != BIG_ENDIAN &&
322 info->lorder != LITTLE_ENDIAN) {
323 errno = EINVAL;
324 return (NULL);
325 }
326 hashp->LORDER = info->lorder;
327 }
328 }
329 /* init_htab should destroy the table and set errno if it fails */
330 if (init_htab(hashp, (size_t)nelem))
331 return (NULL);
332 else
333 return (hashp);
334 }
335 /*
336 * This calls alloc_segs which may run out of memory. Alloc_segs will destroy
337 * the table and set errno, so we just pass the error information along.
338 *
339 * Returns 0 on No Error
340 */
341 static int
init_htab(HTAB * hashp,size_t nelem)342 init_htab(HTAB *hashp, size_t nelem)
343 {
344 int nbuckets;
345 uint32_t nsegs;
346 int l2;
347
348 /*
349 * Divide number of elements by the fill factor and determine a
350 * desired number of buckets. Allocate space for the next greater
351 * power of two number of buckets.
352 */
353 nelem = (nelem - 1) / hashp->FFACTOR + 1;
354
355 _DBFIT(nelem, uint32_t);
356 l2 = __log2(MAX((uint32_t)nelem, 2));
357 nbuckets = 1 << l2;
358
359 hashp->SPARES[l2] = l2 + 1;
360 hashp->SPARES[l2 + 1] = l2 + 1;
361 hashp->OVFL_POINT = l2;
362 hashp->LAST_FREED = 2;
363
364 /* First bitmap page is at: splitpoint l2 page offset 1 */
365 if (__ibitmap(hashp, (int)OADDR_OF(l2, 1), l2 + 1, 0))
366 return (-1);
367
368 hashp->MAX_BUCKET = hashp->LOW_MASK = nbuckets - 1;
369 hashp->HIGH_MASK = (nbuckets << 1) - 1;
370 /* LINTED constant in conditional context */
371 hashp->HDRPAGES = ((MAX(sizeof(HASHHDR), MINHDRSIZE) - 1) >>
372 hashp->BSHIFT) + 1;
373
374 nsegs = (nbuckets - 1) / hashp->SGSIZE + 1;
375 nsegs = 1 << __log2(nsegs);
376
377 if (nsegs > (uint32_t)hashp->DSIZE)
378 hashp->DSIZE = nsegs;
379 return (alloc_segs(hashp, (int)nsegs));
380 }
381
382 /********************** DESTROY/CLOSE ROUTINES ************************/
383
384 /*
385 * Flushes any changes to the file if necessary and destroys the hashp
386 * structure, freeing all allocated space.
387 */
388 static int
hdestroy(HTAB * hashp)389 hdestroy(HTAB *hashp)
390 {
391 int i, save_errno;
392
393 save_errno = 0;
394
395 #ifdef HASH_STATISTICS
396 (void)fprintf(stderr, "hdestroy: accesses %d collisions %d\n",
397 hash_accesses, hash_collisions);
398 (void)fprintf(stderr, "hdestroy: expansions %d\n",
399 hash_expansions);
400 (void)fprintf(stderr, "hdestroy: overflows %d\n",
401 hash_overflows);
402 (void)fprintf(stderr, "keys %d maxp %d segmentcount %d\n",
403 hashp->NKEYS, hashp->MAX_BUCKET, hashp->nsegs);
404
405 for (i = 0; i < NCACHED; i++)
406 (void)fprintf(stderr,
407 "spares[%d] = %d\n", i, hashp->SPARES[i]);
408 #endif
409 /*
410 * Call on buffer manager to free buffers, and if required,
411 * write them to disk.
412 */
413 if (__buf_free(hashp, 1, hashp->save_file))
414 save_errno = errno;
415 if (hashp->dir) {
416 free(*hashp->dir); /* Free initial segments */
417 /* Free extra segments */
418 while (hashp->exsegs--)
419 free(hashp->dir[--hashp->nsegs]);
420 free(hashp->dir);
421 }
422 if (flush_meta(hashp) && !save_errno)
423 save_errno = errno;
424 /* Free Bigmaps */
425 for (i = 0; i < hashp->nmaps; i++)
426 if (hashp->mapp[i])
427 free(hashp->mapp[i]);
428
429 if (hashp->fp != -1)
430 (void)close(hashp->fp);
431
432 free(hashp);
433
434 if (save_errno) {
435 errno = save_errno;
436 return (ERROR);
437 }
438 return (SUCCESS);
439 }
440 /*
441 * Write modified pages to disk
442 *
443 * Returns:
444 * 0 == OK
445 * -1 ERROR
446 */
447 static int
hash_sync(const DB * dbp,uint32_t flags)448 hash_sync(const DB *dbp, uint32_t flags)
449 {
450 HTAB *hashp;
451
452 if (flags != 0) {
453 errno = EINVAL;
454 return (ERROR);
455 }
456
457 if (!dbp)
458 return (ERROR);
459
460 hashp = dbp->internal;
461 if (!hashp->save_file)
462 return (0);
463 if (__buf_free(hashp, 0, 1) || flush_meta(hashp))
464 return (ERROR);
465 hashp->new_file = 0;
466 return (0);
467 }
468
469 /*
470 * Returns:
471 * 0 == OK
472 * -1 indicates that errno should be set
473 */
474 static int
flush_meta(HTAB * hashp)475 flush_meta(HTAB *hashp)
476 {
477 HASHHDR *whdrp;
478 #if BYTE_ORDER == LITTLE_ENDIAN
479 HASHHDR whdr;
480 #endif
481 int fp, i;
482 ssize_t wsize;
483
484 if (!hashp->save_file)
485 return (0);
486 hashp->MAGIC = HASHMAGIC;
487 hashp->VERSION = HASHVERSION;
488 hashp->H_CHARKEY = hashp->hash(CHARKEY, sizeof(CHARKEY));
489
490 fp = hashp->fp;
491 whdrp = &hashp->hdr;
492 #if BYTE_ORDER == LITTLE_ENDIAN
493 whdrp = &whdr;
494 swap_header_copy(&hashp->hdr, whdrp);
495 #endif
496 if ((wsize = pwrite(fp, whdrp, sizeof(HASHHDR), (off_t)0)) == -1)
497 return (-1);
498 else
499 if (wsize != sizeof(HASHHDR)) {
500 errno = EFTYPE;
501 hashp->err = errno;
502 return (-1);
503 }
504 for (i = 0; i < NCACHED; i++)
505 if (hashp->mapp[i])
506 if (__put_page(hashp, (char *)(void *)hashp->mapp[i],
507 (u_int)hashp->BITMAPS[i], 0, 1))
508 return (-1);
509 return (0);
510 }
511
512 /*******************************SEARCH ROUTINES *****************************/
513 /*
514 * All the access routines return
515 *
516 * Returns:
517 * 0 on SUCCESS
518 * 1 to indicate an external ERROR (i.e. key not found, etc)
519 * -1 to indicate an internal ERROR (i.e. out of memory, etc)
520 */
521 static int
hash_get(const DB * dbp,const DBT * key,DBT * data,uint32_t flag)522 hash_get(const DB *dbp, const DBT *key, DBT *data, uint32_t flag)
523 {
524 HTAB *hashp;
525
526 hashp = dbp->internal;
527 if (flag) {
528 hashp->err = errno = EINVAL;
529 return (ERROR);
530 }
531 return (hash_access(hashp, HASH_GET, __UNCONST(key), data));
532 }
533
534 static int
hash_put(const DB * dbp,DBT * key,const DBT * data,uint32_t flag)535 hash_put(const DB *dbp, DBT *key, const DBT *data, uint32_t flag)
536 {
537 HTAB *hashp;
538
539 hashp = dbp->internal;
540 if (flag && flag != R_NOOVERWRITE) {
541 hashp->err = errno = EINVAL;
542 return (ERROR);
543 }
544 if ((hashp->flags & O_ACCMODE) == O_RDONLY) {
545 hashp->err = errno = EPERM;
546 return (ERROR);
547 }
548 /* LINTED const castaway */
549 return (hash_access(hashp, flag == R_NOOVERWRITE ?
550 HASH_PUTNEW : HASH_PUT, __UNCONST(key), __UNCONST(data)));
551 }
552
553 static int
hash_delete(const DB * dbp,const DBT * key,uint32_t flag)554 hash_delete(const DB *dbp, const DBT *key, uint32_t flag)
555 {
556 HTAB *hashp;
557
558 hashp = dbp->internal;
559 if (flag && flag != R_CURSOR) {
560 hashp->err = errno = EINVAL;
561 return (ERROR);
562 }
563 if ((hashp->flags & O_ACCMODE) == O_RDONLY) {
564 hashp->err = errno = EPERM;
565 return (ERROR);
566 }
567 return hash_access(hashp, HASH_DELETE, __UNCONST(key), NULL);
568 }
569
570 /*
571 * Assume that hashp has been set in wrapper routine.
572 */
573 static int
hash_access(HTAB * hashp,ACTION action,DBT * key,DBT * val)574 hash_access(HTAB *hashp, ACTION action, DBT *key, DBT *val)
575 {
576 BUFHEAD *rbufp;
577 BUFHEAD *bufp, *save_bufp;
578 uint16_t *bp;
579 int n, ndx, off;
580 size_t size;
581 char *kp;
582 uint16_t pageno;
583
584 #ifdef HASH_STATISTICS
585 hash_accesses++;
586 #endif
587
588 off = hashp->BSIZE;
589 size = key->size;
590 kp = (char *)key->data;
591 rbufp = __get_buf(hashp, __call_hash(hashp, kp, (int)size), NULL, 0);
592 if (!rbufp)
593 return (ERROR);
594 save_bufp = rbufp;
595
596 /* Pin the bucket chain */
597 rbufp->flags |= BUF_PIN;
598 for (bp = (uint16_t *)(void *)rbufp->page, n = *bp++, ndx = 1; ndx < n;)
599 if (bp[1] >= REAL_KEY) {
600 /* Real key/data pair */
601 if (size == (size_t)(off - *bp) &&
602 memcmp(kp, rbufp->page + *bp, size) == 0)
603 goto found;
604 off = bp[1];
605 #ifdef HASH_STATISTICS
606 hash_collisions++;
607 #endif
608 bp += 2;
609 ndx += 2;
610 } else if (bp[1] == OVFLPAGE) {
611 rbufp = __get_buf(hashp, (uint32_t)*bp, rbufp, 0);
612 if (!rbufp) {
613 save_bufp->flags &= ~BUF_PIN;
614 return (ERROR);
615 }
616 /* FOR LOOP INIT */
617 bp = (uint16_t *)(void *)rbufp->page;
618 n = *bp++;
619 ndx = 1;
620 off = hashp->BSIZE;
621 } else if (bp[1] < REAL_KEY) {
622 if ((ndx =
623 __find_bigpair(hashp, rbufp, ndx, kp, (int)size)) > 0)
624 goto found;
625 if (ndx == -2) {
626 bufp = rbufp;
627 if (!(pageno =
628 __find_last_page(hashp, &bufp))) {
629 ndx = 0;
630 rbufp = bufp;
631 break; /* FOR */
632 }
633 rbufp = __get_buf(hashp, (uint32_t)pageno,
634 bufp, 0);
635 if (!rbufp) {
636 save_bufp->flags &= ~BUF_PIN;
637 return (ERROR);
638 }
639 /* FOR LOOP INIT */
640 bp = (uint16_t *)(void *)rbufp->page;
641 n = *bp++;
642 ndx = 1;
643 off = hashp->BSIZE;
644 } else {
645 save_bufp->flags &= ~BUF_PIN;
646 return (ERROR);
647 }
648 }
649
650 /* Not found */
651 switch (action) {
652 case HASH_PUT:
653 case HASH_PUTNEW:
654 if (__addel(hashp, rbufp, key, val)) {
655 save_bufp->flags &= ~BUF_PIN;
656 return (ERROR);
657 } else {
658 save_bufp->flags &= ~BUF_PIN;
659 return (SUCCESS);
660 }
661 case HASH_GET:
662 case HASH_DELETE:
663 default:
664 save_bufp->flags &= ~BUF_PIN;
665 return (ABNORMAL);
666 }
667
668 found:
669 switch (action) {
670 case HASH_PUTNEW:
671 save_bufp->flags &= ~BUF_PIN;
672 return (ABNORMAL);
673 case HASH_GET:
674 bp = (uint16_t *)(void *)rbufp->page;
675 if (bp[ndx + 1] < REAL_KEY) {
676 if (__big_return(hashp, rbufp, ndx, val, 0))
677 return (ERROR);
678 } else {
679 val->data = (uint8_t *)rbufp->page + (int)bp[ndx + 1];
680 val->size = bp[ndx] - bp[ndx + 1];
681 }
682 break;
683 case HASH_PUT:
684 if ((__delpair(hashp, rbufp, ndx)) ||
685 (__addel(hashp, rbufp, key, val))) {
686 save_bufp->flags &= ~BUF_PIN;
687 return (ERROR);
688 }
689 break;
690 case HASH_DELETE:
691 if (__delpair(hashp, rbufp, ndx))
692 return (ERROR);
693 /*
694 * Our index lags 2 behind on the same page when we are
695 * deleting the element pointed to by the index; otherwise
696 * deleting randomly from an iterated hash produces undefined
697 * results.
698 */
699 if (ndx != hashp->cndx - 2 || rbufp != hashp->cpage)
700 break;
701
702 if (hashp->cndx > 1) {
703 /* Move back one element */
704 hashp->cndx -= 2;
705 } else {
706 /*
707 * Move back one page, and indicate to go to the last
708 * element of the previous page by setting cndx to -1
709 */
710 hashp->cbucket--;
711 hashp->cpage = NULL;
712 hashp->cndx = -1;
713 }
714 break;
715 default:
716 abort();
717 }
718 save_bufp->flags &= ~BUF_PIN;
719 return (SUCCESS);
720 }
721
722 static int
hash_seq(const DB * dbp,DBT * key,DBT * data,uint32_t flag)723 hash_seq(const DB *dbp, DBT *key, DBT *data, uint32_t flag)
724 {
725 uint32_t bucket;
726 BUFHEAD *bufp = NULL; /* XXX: gcc */
727 HTAB *hashp;
728 uint16_t *bp, ndx;
729
730 hashp = dbp->internal;
731 if (flag && flag != R_FIRST && flag != R_NEXT) {
732 hashp->err = errno = EINVAL;
733 return (ERROR);
734 }
735 #ifdef HASH_STATISTICS
736 hash_accesses++;
737 #endif
738 if ((hashp->cbucket < 0) || (flag == R_FIRST)) {
739 hashp->cbucket = 0;
740 hashp->cndx = 1;
741 hashp->cpage = NULL;
742 }
743
744 next_bucket:
745 for (bp = NULL; !bp || !bp[0]; ) {
746 if (!(bufp = hashp->cpage)) {
747 for (bucket = hashp->cbucket;
748 bucket <= (uint32_t)hashp->MAX_BUCKET;
749 bucket++) {
750 bufp = __get_buf(hashp, bucket, NULL, 0);
751 if (!bufp)
752 return (ERROR);
753 hashp->cpage = bufp;
754 bp = (uint16_t *)(void *)bufp->page;
755 if (bp[0])
756 break;
757 }
758 hashp->cbucket = bucket;
759 if (hashp->cbucket > hashp->MAX_BUCKET) {
760 hashp->cbucket = -1;
761 return (ABNORMAL);
762 }
763 if (hashp->cndx == -1) {
764 /* move to the last element of the page */
765 hashp->cndx = 1;
766 while (bp[hashp->cndx - 1] != 0)
767 hashp->cndx += 2;
768 } else {
769 /* start on the first element */
770 hashp->cndx = 1;
771 }
772 } else {
773 bp = (uint16_t *)(void *)hashp->cpage->page;
774 if (flag == R_NEXT || flag == 0) {
775 if (hashp->cndx > bp[0]) {
776 hashp->cpage = NULL;
777 hashp->cbucket++;
778 hashp->cndx = 1;
779 goto next_bucket;
780 }
781 }
782 }
783
784
785 _DIAGASSERT(bp != NULL);
786 _DIAGASSERT(bufp != NULL);
787 while (bp[hashp->cndx + 1] == OVFLPAGE) {
788 bufp = hashp->cpage =
789 __get_buf(hashp, (uint32_t)bp[hashp->cndx], bufp,
790 0);
791 if (!bufp)
792 return (ERROR);
793 bp = (uint16_t *)(void *)(bufp->page);
794 hashp->cndx = 1;
795 }
796 if (!bp[0]) {
797 hashp->cpage = NULL;
798 ++hashp->cbucket;
799 }
800 }
801 ndx = hashp->cndx;
802 if (bp[ndx + 1] < REAL_KEY) {
803 if (__big_keydata(hashp, bufp, key, data, 1))
804 return (ERROR);
805 } else {
806 if (hashp->cpage == NULL)
807 return (ERROR);
808 key->data = (uint8_t *)hashp->cpage->page + bp[ndx];
809 key->size = (ndx > 1 ? bp[ndx - 1] : hashp->BSIZE) - bp[ndx];
810 data->data = (uint8_t *)hashp->cpage->page + bp[ndx + 1];
811 data->size = bp[ndx] - bp[ndx + 1];
812 }
813 hashp->cndx += 2;
814 return (SUCCESS);
815 }
816
817 /********************************* UTILITIES ************************/
818
819 /*
820 * Returns:
821 * 0 ==> OK
822 * -1 ==> Error
823 */
824 int
__expand_table(HTAB * hashp)825 __expand_table(HTAB *hashp)
826 {
827 uint32_t old_bucket, new_bucket;
828 int new_segnum, spare_ndx;
829 size_t dirsize;
830
831 #ifdef HASH_STATISTICS
832 hash_expansions++;
833 #endif
834 new_bucket = ++hashp->MAX_BUCKET;
835 old_bucket = (hashp->MAX_BUCKET & hashp->LOW_MASK);
836
837 new_segnum = new_bucket >> hashp->SSHIFT;
838
839 /* Check if we need a new segment */
840 if (new_segnum >= hashp->nsegs) {
841 /* Check if we need to expand directory */
842 if (new_segnum >= hashp->DSIZE) {
843 /* Reallocate directory */
844 dirsize = hashp->DSIZE * sizeof(SEGMENT *);
845 if (!hash_realloc(&hashp->dir, dirsize, dirsize << 1))
846 return (-1);
847 dirsize <<= 1;
848 _DBFIT(dirsize, uint32_t);
849 hashp->DSIZE = (uint32_t)dirsize;
850 }
851 if ((hashp->dir[new_segnum] =
852 calloc((size_t)hashp->SGSIZE, sizeof(SEGMENT))) == NULL)
853 return (-1);
854 hashp->exsegs++;
855 hashp->nsegs++;
856 }
857 /*
858 * If the split point is increasing (MAX_BUCKET's log base 2
859 * * increases), we need to copy the current contents of the spare
860 * split bucket to the next bucket.
861 */
862 spare_ndx = __log2((uint32_t)(hashp->MAX_BUCKET + 1));
863 if (spare_ndx > hashp->OVFL_POINT) {
864 hashp->SPARES[spare_ndx] = hashp->SPARES[hashp->OVFL_POINT];
865 hashp->OVFL_POINT = spare_ndx;
866 }
867
868 if (new_bucket > (uint32_t)hashp->HIGH_MASK) {
869 /* Starting a new doubling */
870 hashp->LOW_MASK = hashp->HIGH_MASK;
871 hashp->HIGH_MASK = new_bucket | hashp->LOW_MASK;
872 }
873 /* Relocate records to the new bucket */
874 return (__split_page(hashp, old_bucket, new_bucket));
875 }
876
877 /*
878 * If realloc guarantees that the pointer is not destroyed if the realloc
879 * fails, then this routine can go away.
880 */
881 static void *
hash_realloc(SEGMENT ** p_ptr,size_t oldsize,size_t newsize)882 hash_realloc(SEGMENT **p_ptr, size_t oldsize, size_t newsize)
883 {
884 void *p;
885
886 if ((p = malloc(newsize)) != NULL) {
887 memmove(p, *p_ptr, oldsize);
888 memset((char *)p + oldsize, 0, newsize - oldsize);
889 free(*p_ptr);
890 *p_ptr = p;
891 }
892 return (p);
893 }
894
895 uint32_t
__call_hash(HTAB * hashp,char * k,int len)896 __call_hash(HTAB *hashp, char *k, int len)
897 {
898 int n, bucket;
899
900 n = hashp->hash(k, (size_t)len);
901 bucket = n & hashp->HIGH_MASK;
902 if (bucket > hashp->MAX_BUCKET)
903 bucket = bucket & hashp->LOW_MASK;
904 return (bucket);
905 }
906
907 /*
908 * Allocate segment table. On error, destroy the table and set errno.
909 *
910 * Returns 0 on success
911 */
912 static int
alloc_segs(HTAB * hashp,int nsegs)913 alloc_segs(HTAB *hashp, int nsegs)
914 {
915 int i;
916 SEGMENT store;
917
918 int save_errno;
919
920 hashp->dir = calloc((size_t)hashp->DSIZE, sizeof(SEGMENT *));
921 if (hashp->dir == NULL) {
922 save_errno = errno;
923 (void)hdestroy(hashp);
924 errno = save_errno;
925 return (-1);
926 }
927 hashp->nsegs = nsegs;
928 if (nsegs == 0)
929 return 0;
930 /* Allocate segments */
931 store = calloc((size_t)(nsegs << hashp->SSHIFT), sizeof(SEGMENT));
932 if (store == NULL) {
933 save_errno = errno;
934 (void)hdestroy(hashp);
935 errno = save_errno;
936 return (-1);
937 }
938 for (i = 0; i < nsegs; i++)
939 hashp->dir[i] = &store[i << hashp->SSHIFT];
940 return (0);
941 }
942
943 #if BYTE_ORDER == LITTLE_ENDIAN
944 /*
945 * Hashp->hdr needs to be byteswapped.
946 */
947 static void
swap_header_copy(HASHHDR * srcp,HASHHDR * destp)948 swap_header_copy(HASHHDR *srcp, HASHHDR *destp)
949 {
950 size_t i;
951
952 P_32_COPY(srcp->magic, destp->magic);
953 P_32_COPY(srcp->version, destp->version);
954 P_32_COPY(srcp->lorder, destp->lorder);
955 P_32_COPY(srcp->bsize, destp->bsize);
956 P_32_COPY(srcp->bshift, destp->bshift);
957 P_32_COPY(srcp->dsize, destp->dsize);
958 P_32_COPY(srcp->ssize, destp->ssize);
959 P_32_COPY(srcp->sshift, destp->sshift);
960 P_32_COPY(srcp->ovfl_point, destp->ovfl_point);
961 P_32_COPY(srcp->last_freed, destp->last_freed);
962 P_32_COPY(srcp->max_bucket, destp->max_bucket);
963 P_32_COPY(srcp->high_mask, destp->high_mask);
964 P_32_COPY(srcp->low_mask, destp->low_mask);
965 P_32_COPY(srcp->ffactor, destp->ffactor);
966 P_32_COPY(srcp->nkeys, destp->nkeys);
967 P_32_COPY(srcp->hdrpages, destp->hdrpages);
968 P_32_COPY(srcp->h_charkey, destp->h_charkey);
969 for (i = 0; i < NCACHED; i++) {
970 P_32_COPY(srcp->spares[i], destp->spares[i]);
971 P_16_COPY(srcp->bitmaps[i], destp->bitmaps[i]);
972 }
973 }
974
975 static void
swap_header(HTAB * hashp)976 swap_header(HTAB *hashp)
977 {
978 HASHHDR *hdrp;
979 size_t i;
980
981 hdrp = &hashp->hdr;
982
983 M_32_SWAP(hdrp->magic);
984 M_32_SWAP(hdrp->version);
985 M_32_SWAP(hdrp->lorder);
986 M_32_SWAP(hdrp->bsize);
987 M_32_SWAP(hdrp->bshift);
988 M_32_SWAP(hdrp->dsize);
989 M_32_SWAP(hdrp->ssize);
990 M_32_SWAP(hdrp->sshift);
991 M_32_SWAP(hdrp->ovfl_point);
992 M_32_SWAP(hdrp->last_freed);
993 M_32_SWAP(hdrp->max_bucket);
994 M_32_SWAP(hdrp->high_mask);
995 M_32_SWAP(hdrp->low_mask);
996 M_32_SWAP(hdrp->ffactor);
997 M_32_SWAP(hdrp->nkeys);
998 M_32_SWAP(hdrp->hdrpages);
999 M_32_SWAP(hdrp->h_charkey);
1000 for (i = 0; i < NCACHED; i++) {
1001 M_32_SWAP(hdrp->spares[i]);
1002 M_16_SWAP(hdrp->bitmaps[i]);
1003 }
1004 }
1005 #endif
1006