1 /* $OpenBSD: hash.c,v 1.29 2016/09/21 04:38:56 guenther 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 #include <sys/stat.h>
36
37 #include <errno.h>
38 #include <fcntl.h>
39 #include <stdio.h>
40 #include <stdlib.h>
41 #include <string.h>
42 #include <unistd.h>
43 #ifdef DEBUG
44 #include <assert.h>
45 #endif
46
47 #include <db.h>
48 #include "hash.h"
49 #include "page.h"
50 #include "extern.h"
51
52 #define MAXIMUM(a, b) (((a) > (b)) ? (a) : (b))
53
54 static int alloc_segs(HTAB *, int);
55 static int flush_meta(HTAB *);
56 static int hash_access(HTAB *, ACTION, DBT *, DBT *);
57 static int hash_close(DB *);
58 static int hash_delete(const DB *, const DBT *, u_int32_t);
59 static int hash_fd(const DB *);
60 static int hash_get(const DB *, const DBT *, DBT *, u_int32_t);
61 static int hash_put(const DB *, DBT *, const DBT *, u_int32_t);
62 static void *hash_realloc(SEGMENT **, int, int);
63 static int hash_seq(const DB *, DBT *, DBT *, u_int32_t);
64 static int hash_sync(const DB *, u_int32_t);
65 static int hdestroy(HTAB *);
66 static HTAB *init_hash(HTAB *, const char *, const HASHINFO *);
67 static int init_htab(HTAB *, int);
68 #if BYTE_ORDER == LITTLE_ENDIAN
69 static void swap_header(HTAB *);
70 static void swap_header_copy(HASHHDR *, HASHHDR *);
71 #endif
72
73 /* Fast arithmetic, relying on powers of 2, */
74 #define MOD(x, y) ((x) & ((y) - 1))
75
76 #define RETURN_ERROR(ERR, LOC) { save_errno = ERR; goto LOC; }
77
78 /* Return values */
79 #define SUCCESS (0)
80 #define ERROR (-1)
81 #define ABNORMAL (1)
82
83 #ifdef HASH_STATISTICS
84 int hash_accesses, hash_collisions, hash_expansions, hash_overflows;
85 #endif
86
87 /************************** INTERFACE ROUTINES ***************************/
88 /* OPEN/CLOSE */
89
90 DB *
__hash_open(const char * file,int flags,int mode,const HASHINFO * info,int dflags)91 __hash_open(const char *file, int flags, int mode,
92 const HASHINFO *info, /* Special directives for create */
93 int dflags)
94 {
95 HTAB *hashp;
96 struct stat statbuf;
97 DB *dbp;
98 int bpages, hdrsize, new_table, nsegs, save_errno;
99
100 if ((flags & O_ACCMODE) == O_WRONLY) {
101 errno = EINVAL;
102 return (NULL);
103 }
104
105 if (!(hashp = (HTAB *)calloc(1, sizeof(HTAB))))
106 return (NULL);
107 hashp->fp = -1;
108
109 /*
110 * Even if user wants write only, we need to be able to read
111 * the actual file, so we need to open it read/write. But, the
112 * field in the hashp structure needs to be accurate so that
113 * we can check accesses.
114 */
115 hashp->flags = flags;
116
117 if (file) {
118 if ((hashp->fp = open(file, flags | O_CLOEXEC, mode)) == -1)
119 RETURN_ERROR(errno, error0);
120 new_table = fstat(hashp->fp, &statbuf) == 0 &&
121 statbuf.st_size == 0 && (flags & O_ACCMODE) != O_RDONLY;
122 } else
123 new_table = 1;
124
125 if (new_table) {
126 if (!(hashp = init_hash(hashp, file, info)))
127 RETURN_ERROR(errno, error1);
128 } else {
129 /* Table already exists */
130 if (info && info->hash)
131 hashp->hash = info->hash;
132 else
133 hashp->hash = __default_hash;
134
135 hdrsize = read(hashp->fp, &hashp->hdr, sizeof(HASHHDR));
136 #if BYTE_ORDER == LITTLE_ENDIAN
137 swap_header(hashp);
138 #endif
139 if (hdrsize == -1)
140 RETURN_ERROR(errno, error1);
141 if (hdrsize != sizeof(HASHHDR))
142 RETURN_ERROR(EFTYPE, error1);
143 /* Verify file type, versions and hash function */
144 if (hashp->MAGIC != HASHMAGIC)
145 RETURN_ERROR(EFTYPE, error1);
146 #define OLDHASHVERSION 1
147 if (hashp->VERSION != HASHVERSION &&
148 hashp->VERSION != OLDHASHVERSION)
149 RETURN_ERROR(EFTYPE, error1);
150 if (hashp->hash(CHARKEY, sizeof(CHARKEY)) != hashp->H_CHARKEY)
151 RETURN_ERROR(EFTYPE, error1);
152 /*
153 * Figure out how many segments we need. Max_Bucket is the
154 * maximum bucket number, so the number of buckets is
155 * max_bucket + 1.
156 */
157 nsegs = (hashp->MAX_BUCKET + 1 + hashp->SGSIZE - 1) /
158 hashp->SGSIZE;
159 if (alloc_segs(hashp, nsegs))
160 /*
161 * If alloc_segs fails, table will have been destroyed
162 * and errno will have been set.
163 */
164 return (NULL);
165 /* Read in bitmaps */
166 bpages = (hashp->SPARES[hashp->OVFL_POINT] +
167 (hashp->BSIZE << BYTE_SHIFT) - 1) >>
168 (hashp->BSHIFT + BYTE_SHIFT);
169
170 hashp->nmaps = bpages;
171 (void)memset(&hashp->mapp[0], 0, bpages * sizeof(u_int32_t *));
172 }
173
174 /* Initialize Buffer Manager */
175 if (info && info->cachesize)
176 __buf_init(hashp, info->cachesize);
177 else
178 __buf_init(hashp, DEF_BUFSIZE);
179
180 hashp->new_file = new_table;
181 hashp->save_file = file && (hashp->flags & O_RDWR);
182 hashp->cbucket = -1;
183 if (!(dbp = (DB *)malloc(sizeof(DB)))) {
184 save_errno = errno;
185 hdestroy(hashp);
186 errno = save_errno;
187 return (NULL);
188 }
189 dbp->internal = hashp;
190 dbp->close = hash_close;
191 dbp->del = hash_delete;
192 dbp->fd = hash_fd;
193 dbp->get = hash_get;
194 dbp->put = hash_put;
195 dbp->seq = hash_seq;
196 dbp->sync = hash_sync;
197 dbp->type = DB_HASH;
198
199 #ifdef DEBUG
200 (void)fprintf(stderr,
201 "%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",
202 "init_htab:",
203 "TABLE POINTER ", hashp,
204 "BUCKET SIZE ", hashp->BSIZE,
205 "BUCKET SHIFT ", hashp->BSHIFT,
206 "DIRECTORY SIZE ", hashp->DSIZE,
207 "SEGMENT SIZE ", hashp->SGSIZE,
208 "SEGMENT SHIFT ", hashp->SSHIFT,
209 "FILL FACTOR ", hashp->FFACTOR,
210 "MAX BUCKET ", hashp->MAX_BUCKET,
211 "OVFL POINT ", hashp->OVFL_POINT,
212 "LAST FREED ", hashp->LAST_FREED,
213 "HIGH MASK ", hashp->HIGH_MASK,
214 "LOW MASK ", hashp->LOW_MASK,
215 "NSEGS ", hashp->nsegs,
216 "NKEYS ", hashp->NKEYS);
217 #endif
218 #ifdef HASH_STATISTICS
219 hash_overflows = hash_accesses = hash_collisions = hash_expansions = 0;
220 #endif
221 return (dbp);
222
223 error1:
224 if (hashp != NULL)
225 (void)close(hashp->fp);
226
227 error0:
228 free(hashp);
229 errno = save_errno;
230 return (NULL);
231 }
232
233 static int
hash_close(DB * dbp)234 hash_close(DB *dbp)
235 {
236 HTAB *hashp;
237 int retval;
238
239 if (!dbp)
240 return (ERROR);
241
242 hashp = (HTAB *)dbp->internal;
243 retval = hdestroy(hashp);
244 free(dbp);
245 return (retval);
246 }
247
248 static int
hash_fd(const DB * dbp)249 hash_fd(const DB *dbp)
250 {
251 HTAB *hashp;
252
253 if (!dbp)
254 return (ERROR);
255
256 hashp = (HTAB *)dbp->internal;
257 if (hashp->fp == -1) {
258 errno = ENOENT;
259 return (-1);
260 }
261 return (hashp->fp);
262 }
263
264 /************************** LOCAL CREATION ROUTINES **********************/
265 static HTAB *
init_hash(HTAB * hashp,const char * file,const HASHINFO * info)266 init_hash(HTAB *hashp, const char *file, const HASHINFO *info)
267 {
268 struct stat statbuf;
269 int nelem;
270
271 nelem = 1;
272 hashp->NKEYS = 0;
273 hashp->LORDER = BYTE_ORDER;
274 hashp->BSIZE = DEF_BUCKET_SIZE;
275 hashp->BSHIFT = DEF_BUCKET_SHIFT;
276 hashp->SGSIZE = DEF_SEGSIZE;
277 hashp->SSHIFT = DEF_SEGSIZE_SHIFT;
278 hashp->DSIZE = DEF_DIRSIZE;
279 hashp->FFACTOR = DEF_FFACTOR;
280 hashp->hash = __default_hash;
281 memset(hashp->SPARES, 0, sizeof(hashp->SPARES));
282 memset(hashp->BITMAPS, 0, sizeof (hashp->BITMAPS));
283
284 /* Fix bucket size to be optimal for file system */
285 if (file != NULL) {
286 if (stat(file, &statbuf))
287 return (NULL);
288 hashp->BSIZE = statbuf.st_blksize;
289 hashp->BSHIFT = __log2(hashp->BSIZE);
290 }
291
292 if (info) {
293 if (info->bsize) {
294 /* Round pagesize up to power of 2 */
295 hashp->BSHIFT = __log2(info->bsize);
296 hashp->BSIZE = 1 << hashp->BSHIFT;
297 if (hashp->BSIZE > MAX_BSIZE) {
298 errno = EINVAL;
299 return (NULL);
300 }
301 }
302 if (info->ffactor)
303 hashp->FFACTOR = info->ffactor;
304 if (info->hash)
305 hashp->hash = info->hash;
306 if (info->nelem)
307 nelem = info->nelem;
308 if (info->lorder) {
309 if (info->lorder != BIG_ENDIAN &&
310 info->lorder != LITTLE_ENDIAN) {
311 errno = EINVAL;
312 return (NULL);
313 }
314 hashp->LORDER = info->lorder;
315 }
316 }
317 /* init_htab should destroy the table and set errno if it fails */
318 if (init_htab(hashp, nelem))
319 return (NULL);
320 else
321 return (hashp);
322 }
323 /*
324 * This calls alloc_segs which may run out of memory. Alloc_segs will destroy
325 * the table and set errno, so we just pass the error information along.
326 *
327 * Returns 0 on No Error
328 */
329 static int
init_htab(HTAB * hashp,int nelem)330 init_htab(HTAB *hashp, int nelem)
331 {
332 int nbuckets, nsegs, l2;
333
334 /*
335 * Divide number of elements by the fill factor and determine a
336 * desired number of buckets. Allocate space for the next greater
337 * power of two number of buckets.
338 */
339 nelem = (nelem - 1) / hashp->FFACTOR + 1;
340
341 l2 = __log2(MAXIMUM(nelem, 2));
342 nbuckets = 1 << l2;
343
344 hashp->SPARES[l2] = l2 + 1;
345 hashp->SPARES[l2 + 1] = l2 + 1;
346 hashp->OVFL_POINT = l2;
347 hashp->LAST_FREED = 2;
348
349 /* First bitmap page is at: splitpoint l2 page offset 1 */
350 if (__ibitmap(hashp, OADDR_OF(l2, 1), l2 + 1, 0))
351 return (-1);
352
353 hashp->MAX_BUCKET = hashp->LOW_MASK = nbuckets - 1;
354 hashp->HIGH_MASK = (nbuckets << 1) - 1;
355 hashp->HDRPAGES = ((MAXIMUM(sizeof(HASHHDR), MINHDRSIZE) - 1) >>
356 hashp->BSHIFT) + 1;
357
358 nsegs = (nbuckets - 1) / hashp->SGSIZE + 1;
359 nsegs = 1 << __log2(nsegs);
360
361 if (nsegs > hashp->DSIZE)
362 hashp->DSIZE = nsegs;
363 return (alloc_segs(hashp, nsegs));
364 }
365
366 /********************** DESTROY/CLOSE ROUTINES ************************/
367
368 /*
369 * Flushes any changes to the file if necessary and destroys the hashp
370 * structure, freeing all allocated space.
371 */
372 static int
hdestroy(HTAB * hashp)373 hdestroy(HTAB *hashp)
374 {
375 int i, save_errno;
376
377 save_errno = 0;
378
379 #ifdef HASH_STATISTICS
380 (void)fprintf(stderr, "hdestroy: accesses %ld collisions %ld\n",
381 hash_accesses, hash_collisions);
382 (void)fprintf(stderr, "hdestroy: expansions %ld\n",
383 hash_expansions);
384 (void)fprintf(stderr, "hdestroy: overflows %ld\n",
385 hash_overflows);
386 (void)fprintf(stderr, "keys %ld maxp %d segmentcount %d\n",
387 hashp->NKEYS, hashp->MAX_BUCKET, hashp->nsegs);
388
389 for (i = 0; i < NCACHED; i++)
390 (void)fprintf(stderr,
391 "spares[%d] = %d\n", i, hashp->SPARES[i]);
392 #endif
393 /*
394 * Call on buffer manager to free buffers, and if required,
395 * write them to disk.
396 */
397 if (__buf_free(hashp, 1, hashp->save_file))
398 save_errno = errno;
399 if (hashp->dir) {
400 free(*hashp->dir); /* Free initial segments */
401 /* Free extra segments */
402 while (hashp->exsegs--)
403 free(hashp->dir[--hashp->nsegs]);
404 free(hashp->dir);
405 }
406 if (flush_meta(hashp) && !save_errno)
407 save_errno = errno;
408 /* Free Bigmaps */
409 for (i = 0; i < hashp->nmaps; i++)
410 free(hashp->mapp[i]);
411 free(hashp->tmp_key);
412 free(hashp->tmp_buf);
413
414 if (hashp->fp != -1)
415 (void)close(hashp->fp);
416
417 free(hashp);
418
419 if (save_errno) {
420 errno = save_errno;
421 return (ERROR);
422 }
423 return (SUCCESS);
424 }
425 /*
426 * Write modified pages to disk
427 *
428 * Returns:
429 * 0 == OK
430 * -1 ERROR
431 */
432 static int
hash_sync(const DB * dbp,u_int32_t flags)433 hash_sync(const DB *dbp, u_int32_t flags)
434 {
435 HTAB *hashp;
436
437 if (flags != 0) {
438 errno = EINVAL;
439 return (ERROR);
440 }
441
442 if (!dbp)
443 return (ERROR);
444
445 hashp = (HTAB *)dbp->internal;
446 if (!hashp->save_file)
447 return (0);
448 if (__buf_free(hashp, 0, 1) || flush_meta(hashp))
449 return (ERROR);
450 hashp->new_file = 0;
451 return (0);
452 }
453
454 /*
455 * Returns:
456 * 0 == OK
457 * -1 indicates that errno should be set
458 */
459 static int
flush_meta(HTAB * hashp)460 flush_meta(HTAB *hashp)
461 {
462 HASHHDR *whdrp;
463 #if BYTE_ORDER == LITTLE_ENDIAN
464 HASHHDR whdr;
465 #endif
466 int fp, i, wsize;
467
468 if (!hashp->save_file)
469 return (0);
470 hashp->MAGIC = HASHMAGIC;
471 hashp->VERSION = HASHVERSION;
472 hashp->H_CHARKEY = hashp->hash(CHARKEY, sizeof(CHARKEY));
473
474 fp = hashp->fp;
475 whdrp = &hashp->hdr;
476 #if BYTE_ORDER == LITTLE_ENDIAN
477 whdrp = &whdr;
478 swap_header_copy(&hashp->hdr, whdrp);
479 #endif
480 if ((wsize = pwrite(fp, whdrp, sizeof(HASHHDR), 0)) == -1)
481 return (-1);
482 else
483 if (wsize != sizeof(HASHHDR)) {
484 errno = EFTYPE;
485 hashp->err = errno;
486 return (-1);
487 }
488 for (i = 0; i < NCACHED; i++)
489 if (hashp->mapp[i])
490 if (__put_page(hashp, (char *)hashp->mapp[i],
491 hashp->BITMAPS[i], 0, 1))
492 return (-1);
493 return (0);
494 }
495
496 /*******************************SEARCH ROUTINES *****************************/
497 /*
498 * All the access routines return
499 *
500 * Returns:
501 * 0 on SUCCESS
502 * 1 to indicate an external ERROR (i.e. key not found, etc)
503 * -1 to indicate an internal ERROR (i.e. out of memory, etc)
504 */
505 static int
hash_get(const DB * dbp,const DBT * key,DBT * data,u_int32_t flag)506 hash_get(const DB *dbp, const DBT *key, DBT *data, u_int32_t flag)
507 {
508 HTAB *hashp;
509
510 hashp = (HTAB *)dbp->internal;
511 if (flag) {
512 hashp->err = errno = EINVAL;
513 return (ERROR);
514 }
515 return (hash_access(hashp, HASH_GET, (DBT *)key, data));
516 }
517
518 static int
hash_put(const DB * dbp,DBT * key,const DBT * data,u_int32_t flag)519 hash_put(const DB *dbp, DBT *key, const DBT *data, u_int32_t flag)
520 {
521 HTAB *hashp;
522
523 hashp = (HTAB *)dbp->internal;
524 if (flag && flag != R_NOOVERWRITE) {
525 hashp->err = errno = EINVAL;
526 return (ERROR);
527 }
528 if ((hashp->flags & O_ACCMODE) == O_RDONLY) {
529 hashp->err = errno = EPERM;
530 return (ERROR);
531 }
532 return (hash_access(hashp, flag == R_NOOVERWRITE ?
533 HASH_PUTNEW : HASH_PUT, (DBT *)key, (DBT *)data));
534 }
535
536 static int
hash_delete(const DB * dbp,const DBT * key,u_int32_t flag)537 hash_delete(const DB *dbp, const DBT *key,
538 u_int32_t flag) /* Ignored */
539 {
540 HTAB *hashp;
541
542 hashp = (HTAB *)dbp->internal;
543 if (flag && flag != R_CURSOR) {
544 hashp->err = errno = EINVAL;
545 return (ERROR);
546 }
547 if ((hashp->flags & O_ACCMODE) == O_RDONLY) {
548 hashp->err = errno = EPERM;
549 return (ERROR);
550 }
551 return (hash_access(hashp, HASH_DELETE, (DBT *)key, NULL));
552 }
553
554 /*
555 * Assume that hashp has been set in wrapper routine.
556 */
557 static int
hash_access(HTAB * hashp,ACTION action,DBT * key,DBT * val)558 hash_access(HTAB *hashp, ACTION action, DBT *key, DBT *val)
559 {
560 BUFHEAD *rbufp;
561 BUFHEAD *bufp, *save_bufp;
562 u_int16_t *bp;
563 int n, ndx, off, size;
564 char *kp;
565 u_int16_t pageno;
566
567 #ifdef HASH_STATISTICS
568 hash_accesses++;
569 #endif
570
571 off = hashp->BSIZE;
572 size = key->size;
573 kp = (char *)key->data;
574 rbufp = __get_buf(hashp, __call_hash(hashp, kp, size), NULL, 0);
575 if (!rbufp)
576 return (ERROR);
577 save_bufp = rbufp;
578
579 /* Pin the bucket chain */
580 rbufp->flags |= BUF_PIN;
581 for (bp = (u_int16_t *)rbufp->page, n = *bp++, ndx = 1; ndx < n;)
582 if (bp[1] >= REAL_KEY) {
583 /* Real key/data pair */
584 if (size == off - *bp &&
585 memcmp(kp, rbufp->page + *bp, size) == 0)
586 goto found;
587 off = bp[1];
588 #ifdef HASH_STATISTICS
589 hash_collisions++;
590 #endif
591 bp += 2;
592 ndx += 2;
593 } else if (bp[1] == OVFLPAGE) {
594 rbufp = __get_buf(hashp, *bp, rbufp, 0);
595 if (!rbufp) {
596 save_bufp->flags &= ~BUF_PIN;
597 return (ERROR);
598 }
599 /* FOR LOOP INIT */
600 bp = (u_int16_t *)rbufp->page;
601 n = *bp++;
602 ndx = 1;
603 off = hashp->BSIZE;
604 } else if (bp[1] < REAL_KEY) {
605 if ((ndx =
606 __find_bigpair(hashp, rbufp, ndx, kp, size)) > 0)
607 goto found;
608 if (ndx == -2) {
609 bufp = rbufp;
610 if (!(pageno =
611 __find_last_page(hashp, &bufp))) {
612 ndx = 0;
613 rbufp = bufp;
614 break; /* FOR */
615 }
616 rbufp = __get_buf(hashp, pageno, bufp, 0);
617 if (!rbufp) {
618 save_bufp->flags &= ~BUF_PIN;
619 return (ERROR);
620 }
621 /* FOR LOOP INIT */
622 bp = (u_int16_t *)rbufp->page;
623 n = *bp++;
624 ndx = 1;
625 off = hashp->BSIZE;
626 } else {
627 save_bufp->flags &= ~BUF_PIN;
628 return (ERROR);
629 }
630 }
631
632 /* Not found */
633 switch (action) {
634 case HASH_PUT:
635 case HASH_PUTNEW:
636 if (__addel(hashp, rbufp, key, val)) {
637 save_bufp->flags &= ~BUF_PIN;
638 return (ERROR);
639 } else {
640 save_bufp->flags &= ~BUF_PIN;
641 return (SUCCESS);
642 }
643 case HASH_GET:
644 case HASH_DELETE:
645 default:
646 save_bufp->flags &= ~BUF_PIN;
647 return (ABNORMAL);
648 }
649
650 found:
651 switch (action) {
652 case HASH_PUTNEW:
653 save_bufp->flags &= ~BUF_PIN;
654 return (ABNORMAL);
655 case HASH_GET:
656 bp = (u_int16_t *)rbufp->page;
657 if (bp[ndx + 1] < REAL_KEY) {
658 if (__big_return(hashp, rbufp, ndx, val, 0))
659 return (ERROR);
660 } else {
661 val->data = (u_char *)rbufp->page + (int)bp[ndx + 1];
662 val->size = bp[ndx] - bp[ndx + 1];
663 }
664 break;
665 case HASH_PUT:
666 if ((__delpair(hashp, rbufp, ndx)) ||
667 (__addel(hashp, rbufp, key, val))) {
668 save_bufp->flags &= ~BUF_PIN;
669 return (ERROR);
670 }
671 break;
672 case HASH_DELETE:
673 if (__delpair(hashp, rbufp, ndx))
674 return (ERROR);
675 break;
676 default:
677 abort();
678 }
679 save_bufp->flags &= ~BUF_PIN;
680 return (SUCCESS);
681 }
682
683 static int
hash_seq(const DB * dbp,DBT * key,DBT * data,u_int32_t flag)684 hash_seq(const DB *dbp, DBT *key, DBT *data, u_int32_t flag)
685 {
686 u_int32_t bucket;
687 BUFHEAD *bufp;
688 HTAB *hashp;
689 u_int16_t *bp, ndx;
690
691 hashp = (HTAB *)dbp->internal;
692 if (flag && flag != R_FIRST && flag != R_NEXT) {
693 hashp->err = errno = EINVAL;
694 return (ERROR);
695 }
696 #ifdef HASH_STATISTICS
697 hash_accesses++;
698 #endif
699 if ((hashp->cbucket < 0) || (flag == R_FIRST)) {
700 hashp->cbucket = 0;
701 hashp->cndx = 1;
702 hashp->cpage = NULL;
703 }
704 next_bucket:
705 for (bp = NULL; !bp || !bp[0]; ) {
706 if (!(bufp = hashp->cpage)) {
707 for (bucket = hashp->cbucket;
708 bucket <= hashp->MAX_BUCKET;
709 bucket++, hashp->cndx = 1) {
710 bufp = __get_buf(hashp, bucket, NULL, 0);
711 if (!bufp)
712 return (ERROR);
713 hashp->cpage = bufp;
714 bp = (u_int16_t *)bufp->page;
715 if (bp[0])
716 break;
717 }
718 hashp->cbucket = bucket;
719 if (hashp->cbucket > hashp->MAX_BUCKET) {
720 hashp->cbucket = -1;
721 return (ABNORMAL);
722 }
723 } else {
724 bp = (u_int16_t *)hashp->cpage->page;
725 if (flag == R_NEXT) {
726 hashp->cndx += 2;
727 if (hashp->cndx > bp[0]) {
728 hashp->cpage = NULL;
729 hashp->cbucket++;
730 hashp->cndx = 1;
731 goto next_bucket;
732 }
733 }
734 }
735
736 #ifdef DEBUG
737 assert(bp);
738 assert(bufp);
739 #endif
740 while (bp[hashp->cndx + 1] == OVFLPAGE) {
741 bufp = hashp->cpage =
742 __get_buf(hashp, bp[hashp->cndx], bufp, 0);
743 if (!bufp)
744 return (ERROR);
745 bp = (u_int16_t *)(bufp->page);
746 hashp->cndx = 1;
747 }
748 if (!bp[0]) {
749 hashp->cpage = NULL;
750 ++hashp->cbucket;
751 }
752 }
753 ndx = hashp->cndx;
754 if (bp[ndx + 1] < REAL_KEY) {
755 if (__big_keydata(hashp, bufp, key, data, 1))
756 return (ERROR);
757 } else {
758 if (hashp->cpage == 0)
759 return (ERROR);
760 key->data = (u_char *)hashp->cpage->page + bp[ndx];
761 key->size = (ndx > 1 ? bp[ndx - 1] : hashp->BSIZE) - bp[ndx];
762 data->data = (u_char *)hashp->cpage->page + bp[ndx + 1];
763 data->size = bp[ndx] - bp[ndx + 1];
764 }
765 return (SUCCESS);
766 }
767
768 /********************************* UTILITIES ************************/
769
770 /*
771 * Returns:
772 * 0 ==> OK
773 * -1 ==> Error
774 */
775 int
__expand_table(HTAB * hashp)776 __expand_table(HTAB *hashp)
777 {
778 u_int32_t old_bucket, new_bucket;
779 int dirsize, new_segnum, spare_ndx;
780
781 #ifdef HASH_STATISTICS
782 hash_expansions++;
783 #endif
784 new_bucket = ++hashp->MAX_BUCKET;
785 old_bucket = (hashp->MAX_BUCKET & hashp->LOW_MASK);
786
787 new_segnum = new_bucket >> hashp->SSHIFT;
788
789 /* Check if we need a new segment */
790 if (new_segnum >= hashp->nsegs) {
791 /* Check if we need to expand directory */
792 if (new_segnum >= hashp->DSIZE) {
793 /* Reallocate directory */
794 dirsize = hashp->DSIZE * sizeof(SEGMENT *);
795 if (!hash_realloc(&hashp->dir, dirsize, dirsize << 1))
796 return (-1);
797 hashp->DSIZE = dirsize << 1;
798 }
799 if ((hashp->dir[new_segnum] =
800 (SEGMENT)calloc(hashp->SGSIZE, sizeof(SEGMENT))) == NULL)
801 return (-1);
802 hashp->exsegs++;
803 hashp->nsegs++;
804 }
805 /*
806 * If the split point is increasing (MAX_BUCKET's log base 2
807 * * increases), we need to copy the current contents of the spare
808 * split bucket to the next bucket.
809 */
810 spare_ndx = __log2(hashp->MAX_BUCKET + 1);
811 if (spare_ndx > hashp->OVFL_POINT) {
812 hashp->SPARES[spare_ndx] = hashp->SPARES[hashp->OVFL_POINT];
813 hashp->OVFL_POINT = spare_ndx;
814 }
815
816 if (new_bucket > hashp->HIGH_MASK) {
817 /* Starting a new doubling */
818 hashp->LOW_MASK = hashp->HIGH_MASK;
819 hashp->HIGH_MASK = new_bucket | hashp->LOW_MASK;
820 }
821 /* Relocate records to the new bucket */
822 return (__split_page(hashp, old_bucket, new_bucket));
823 }
824
825 /*
826 * If realloc guarantees that the pointer is not destroyed if the realloc
827 * fails, then this routine can go away.
828 */
829 static void *
hash_realloc(SEGMENT ** p_ptr,int oldsize,int newsize)830 hash_realloc(SEGMENT **p_ptr, int oldsize, int newsize)
831 {
832 void *p;
833
834 if ((p = malloc(newsize))) {
835 memmove(p, *p_ptr, oldsize);
836 memset((char *)p + oldsize, 0, newsize - oldsize);
837 free(*p_ptr);
838 *p_ptr = p;
839 }
840 return (p);
841 }
842
843 u_int32_t
__call_hash(HTAB * hashp,char * k,int len)844 __call_hash(HTAB *hashp, char *k, int len)
845 {
846 int n, bucket;
847
848 n = hashp->hash(k, len);
849 bucket = n & hashp->HIGH_MASK;
850 if (bucket > hashp->MAX_BUCKET)
851 bucket = bucket & hashp->LOW_MASK;
852 return (bucket);
853 }
854
855 /*
856 * Allocate segment table. On error, destroy the table and set errno.
857 *
858 * Returns 0 on success
859 */
860 static int
alloc_segs(HTAB * hashp,int nsegs)861 alloc_segs(HTAB *hashp, int nsegs)
862 {
863 int i;
864 SEGMENT store;
865
866 int save_errno;
867
868 if ((hashp->dir =
869 (SEGMENT *)calloc(hashp->DSIZE, sizeof(SEGMENT *))) == NULL) {
870 save_errno = errno;
871 (void)hdestroy(hashp);
872 errno = save_errno;
873 return (-1);
874 }
875 hashp->nsegs = nsegs;
876 if (nsegs == 0)
877 return (0);
878 /* Allocate segments */
879 if ((store = (SEGMENT)calloc(nsegs << hashp->SSHIFT,
880 sizeof(SEGMENT))) == NULL) {
881 save_errno = errno;
882 (void)hdestroy(hashp);
883 errno = save_errno;
884 return (-1);
885 }
886 for (i = 0; i < nsegs; i++)
887 hashp->dir[i] = &store[i << hashp->SSHIFT];
888 return (0);
889 }
890
891 #if BYTE_ORDER == LITTLE_ENDIAN
892 /*
893 * Hashp->hdr needs to be byteswapped.
894 */
895 static void
swap_header_copy(HASHHDR * srcp,HASHHDR * destp)896 swap_header_copy(HASHHDR *srcp, HASHHDR *destp)
897 {
898 int i;
899
900 P_32_COPY(srcp->magic, destp->magic);
901 P_32_COPY(srcp->version, destp->version);
902 P_32_COPY(srcp->lorder, destp->lorder);
903 P_32_COPY(srcp->bsize, destp->bsize);
904 P_32_COPY(srcp->bshift, destp->bshift);
905 P_32_COPY(srcp->dsize, destp->dsize);
906 P_32_COPY(srcp->ssize, destp->ssize);
907 P_32_COPY(srcp->sshift, destp->sshift);
908 P_32_COPY(srcp->ovfl_point, destp->ovfl_point);
909 P_32_COPY(srcp->last_freed, destp->last_freed);
910 P_32_COPY(srcp->max_bucket, destp->max_bucket);
911 P_32_COPY(srcp->high_mask, destp->high_mask);
912 P_32_COPY(srcp->low_mask, destp->low_mask);
913 P_32_COPY(srcp->ffactor, destp->ffactor);
914 P_32_COPY(srcp->nkeys, destp->nkeys);
915 P_32_COPY(srcp->hdrpages, destp->hdrpages);
916 P_32_COPY(srcp->h_charkey, destp->h_charkey);
917 for (i = 0; i < NCACHED; i++) {
918 P_32_COPY(srcp->spares[i], destp->spares[i]);
919 P_16_COPY(srcp->bitmaps[i], destp->bitmaps[i]);
920 }
921 }
922
923 static void
swap_header(HTAB * hashp)924 swap_header(HTAB *hashp)
925 {
926 HASHHDR *hdrp;
927 int i;
928
929 hdrp = &hashp->hdr;
930
931 M_32_SWAP(hdrp->magic);
932 M_32_SWAP(hdrp->version);
933 M_32_SWAP(hdrp->lorder);
934 M_32_SWAP(hdrp->bsize);
935 M_32_SWAP(hdrp->bshift);
936 M_32_SWAP(hdrp->dsize);
937 M_32_SWAP(hdrp->ssize);
938 M_32_SWAP(hdrp->sshift);
939 M_32_SWAP(hdrp->ovfl_point);
940 M_32_SWAP(hdrp->last_freed);
941 M_32_SWAP(hdrp->max_bucket);
942 M_32_SWAP(hdrp->high_mask);
943 M_32_SWAP(hdrp->low_mask);
944 M_32_SWAP(hdrp->ffactor);
945 M_32_SWAP(hdrp->nkeys);
946 M_32_SWAP(hdrp->hdrpages);
947 M_32_SWAP(hdrp->h_charkey);
948 for (i = 0; i < NCACHED; i++) {
949 M_32_SWAP(hdrp->spares[i]);
950 M_16_SWAP(hdrp->bitmaps[i]);
951 }
952 }
953 #endif
954