1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
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 defined(LIBC_SCCS) && !defined(lint)
36 static char sccsid[] = "@(#)hash.c 8.9 (Berkeley) 6/16/94";
37 #endif /* LIBC_SCCS and not lint */
38 #include "namespace.h"
39 #include <sys/param.h>
40 #include <sys/stat.h>
41
42 #include <errno.h>
43 #include <fcntl.h>
44 #include <stdio.h>
45 #include <stdlib.h>
46 #include <string.h>
47 #include <unistd.h>
48 #ifdef DEBUG
49 #include <assert.h>
50 #endif
51 #include "un-namespace.h"
52
53 #include <db.h>
54 #include "hash.h"
55 #include "page.h"
56 #include "extern.h"
57
58 static int alloc_segs(HTAB *, int);
59 static int flush_meta(HTAB *);
60 static int hash_access(HTAB *, ACTION, DBT *, DBT *);
61 static int hash_close(DB *);
62 static int hash_delete(const DB *, const DBT *, u_int32_t);
63 static int hash_fd(const DB *);
64 static int hash_get(const DB *, const DBT *, DBT *, u_int32_t);
65 static int hash_put(const DB *, DBT *, const DBT *, u_int32_t);
66 static void *hash_realloc(SEGMENT **, int, int);
67 static int hash_seq(const DB *, DBT *, DBT *, u_int32_t);
68 static int hash_sync(const DB *, u_int32_t);
69 static int hdestroy(HTAB *);
70 static HTAB *init_hash(HTAB *, const char *, const HASHINFO *);
71 static int init_htab(HTAB *, int);
72 #if BYTE_ORDER == LITTLE_ENDIAN
73 static void swap_header(HTAB *);
74 static void swap_header_copy(HASHHDR *, HASHHDR *);
75 #endif
76
77 /* Fast arithmetic, relying on powers of 2, */
78 #define MOD(x, y) ((x) & ((y) - 1))
79
80 #define RETURN_ERROR(ERR, LOC) { save_errno = ERR; goto LOC; }
81
82 /* Return values */
83 #define SUCCESS (0)
84 #define ERROR (-1)
85 #define ABNORMAL (1)
86
87 #ifdef HASH_STATISTICS
88 int hash_accesses, hash_collisions, hash_expansions, hash_overflows;
89 #endif
90
91 /************************** INTERFACE ROUTINES ***************************/
92 /* OPEN/CLOSE */
93
94 /* ARGSUSED */
95 DB *
__hash_open(const char * file,int flags,int mode,const HASHINFO * info,int dflags)96 __hash_open(const char *file, int flags, int mode,
97 const HASHINFO *info, /* Special directives for create */
98 int dflags)
99 {
100 HTAB *hashp;
101 struct stat statbuf;
102 DB *dbp;
103 int bpages, hdrsize, new_table, nsegs, save_errno;
104
105 if ((flags & O_ACCMODE) == O_WRONLY) {
106 errno = EINVAL;
107 return (NULL);
108 }
109
110 if (!(hashp = (HTAB *)calloc(1, sizeof(HTAB))))
111 return (NULL);
112 hashp->fp = -1;
113
114 /*
115 * Even if user wants write only, we need to be able to read
116 * the actual file, so we need to open it read/write. But, the
117 * field in the hashp structure needs to be accurate so that
118 * we can check accesses.
119 */
120 hashp->flags = flags;
121
122 if (file) {
123 if ((hashp->fp = _open(file, flags | O_CLOEXEC, mode)) == -1)
124 RETURN_ERROR(errno, error0);
125 new_table = _fstat(hashp->fp, &statbuf) == 0 &&
126 statbuf.st_size == 0 && (flags & O_ACCMODE) != O_RDONLY;
127 } else
128 new_table = 1;
129
130 if (new_table) {
131 if (!(hashp = init_hash(hashp, file, info)))
132 RETURN_ERROR(errno, error1);
133 } else {
134 /* Table already exists */
135 if (info && info->hash)
136 hashp->hash = info->hash;
137 else
138 hashp->hash = __default_hash;
139
140 hdrsize = _read(hashp->fp, &hashp->hdr, sizeof(HASHHDR));
141 #if BYTE_ORDER == LITTLE_ENDIAN
142 swap_header(hashp);
143 #endif
144 if (hdrsize == -1)
145 RETURN_ERROR(errno, error1);
146 if (hdrsize != sizeof(HASHHDR))
147 RETURN_ERROR(EFTYPE, error1);
148 /* Verify file type, versions and hash function */
149 if (hashp->MAGIC != HASHMAGIC)
150 RETURN_ERROR(EFTYPE, error1);
151 #define OLDHASHVERSION 1
152 if (hashp->VERSION != HASHVERSION &&
153 hashp->VERSION != OLDHASHVERSION)
154 RETURN_ERROR(EFTYPE, error1);
155 if ((int32_t)hashp->hash(CHARKEY, sizeof(CHARKEY)) != hashp->H_CHARKEY)
156 RETURN_ERROR(EFTYPE, error1);
157 /*
158 * Figure out how many segments we need. Max_Bucket is the
159 * maximum bucket number, so the number of buckets is
160 * max_bucket + 1.
161 */
162 nsegs = howmany(hashp->MAX_BUCKET + 1, hashp->SGSIZE);
163 if (alloc_segs(hashp, nsegs))
164 /*
165 * If alloc_segs fails, table will have been destroyed
166 * and errno will have been set.
167 */
168 return (NULL);
169 /* Read in bitmaps */
170 bpages = (hashp->SPARES[hashp->OVFL_POINT] +
171 (hashp->BSIZE << BYTE_SHIFT) - 1) >>
172 (hashp->BSHIFT + BYTE_SHIFT);
173
174 hashp->nmaps = bpages;
175 (void)memset(&hashp->mapp[0], 0, bpages * sizeof(u_int32_t *));
176 }
177
178 /* Initialize Buffer Manager */
179 if (info && info->cachesize)
180 __buf_init(hashp, info->cachesize);
181 else
182 __buf_init(hashp, DEF_BUFSIZE);
183
184 hashp->new_file = new_table;
185 hashp->save_file = file && (hashp->flags & O_RDWR);
186 hashp->cbucket = -1;
187 if (!(dbp = (DB *)malloc(sizeof(DB)))) {
188 save_errno = errno;
189 hdestroy(hashp);
190 errno = save_errno;
191 return (NULL);
192 }
193 dbp->internal = hashp;
194 dbp->close = hash_close;
195 dbp->del = hash_delete;
196 dbp->fd = hash_fd;
197 dbp->get = hash_get;
198 dbp->put = hash_put;
199 dbp->seq = hash_seq;
200 dbp->sync = hash_sync;
201 dbp->type = DB_HASH;
202
203 #ifdef DEBUG
204 (void)fprintf(stderr,
205 "%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",
206 "init_htab:",
207 "TABLE POINTER ", hashp,
208 "BUCKET SIZE ", hashp->BSIZE,
209 "BUCKET SHIFT ", hashp->BSHIFT,
210 "DIRECTORY SIZE ", hashp->DSIZE,
211 "SEGMENT SIZE ", hashp->SGSIZE,
212 "SEGMENT SHIFT ", hashp->SSHIFT,
213 "FILL FACTOR ", hashp->FFACTOR,
214 "MAX BUCKET ", hashp->MAX_BUCKET,
215 "OVFL POINT ", hashp->OVFL_POINT,
216 "LAST FREED ", hashp->LAST_FREED,
217 "HIGH MASK ", hashp->HIGH_MASK,
218 "LOW MASK ", hashp->LOW_MASK,
219 "NSEGS ", hashp->nsegs,
220 "NKEYS ", hashp->NKEYS);
221 #endif
222 #ifdef HASH_STATISTICS
223 hash_overflows = hash_accesses = hash_collisions = hash_expansions = 0;
224 #endif
225 return (dbp);
226
227 error1:
228 if (hashp != NULL)
229 (void)_close(hashp->fp);
230
231 error0:
232 free(hashp);
233 errno = save_errno;
234 return (NULL);
235 }
236
237 static int
hash_close(DB * dbp)238 hash_close(DB *dbp)
239 {
240 HTAB *hashp;
241 int retval;
242
243 if (!dbp)
244 return (ERROR);
245
246 hashp = (HTAB *)dbp->internal;
247 retval = hdestroy(hashp);
248 free(dbp);
249 return (retval);
250 }
251
252 static int
hash_fd(const DB * dbp)253 hash_fd(const DB *dbp)
254 {
255 HTAB *hashp;
256
257 if (!dbp)
258 return (ERROR);
259
260 hashp = (HTAB *)dbp->internal;
261 if (hashp->fp == -1) {
262 errno = ENOENT;
263 return (-1);
264 }
265 return (hashp->fp);
266 }
267
268 /************************** LOCAL CREATION ROUTINES **********************/
269 static HTAB *
init_hash(HTAB * hashp,const char * file,const HASHINFO * info)270 init_hash(HTAB *hashp, const char *file, const HASHINFO *info)
271 {
272 struct stat statbuf;
273 int nelem;
274
275 nelem = 1;
276 hashp->NKEYS = 0;
277 hashp->LORDER = BYTE_ORDER;
278 hashp->BSIZE = DEF_BUCKET_SIZE;
279 hashp->BSHIFT = DEF_BUCKET_SHIFT;
280 hashp->SGSIZE = DEF_SEGSIZE;
281 hashp->SSHIFT = DEF_SEGSIZE_SHIFT;
282 hashp->DSIZE = DEF_DIRSIZE;
283 hashp->FFACTOR = DEF_FFACTOR;
284 hashp->hash = __default_hash;
285 memset(hashp->SPARES, 0, sizeof(hashp->SPARES));
286 memset(hashp->BITMAPS, 0, sizeof (hashp->BITMAPS));
287
288 /* Fix bucket size to be optimal for file system */
289 if (file != NULL) {
290 if (stat(file, &statbuf))
291 return (NULL);
292 hashp->BSIZE = statbuf.st_blksize;
293 if (hashp->BSIZE > MAX_BSIZE)
294 hashp->BSIZE = MAX_BSIZE;
295 hashp->BSHIFT = __log2(hashp->BSIZE);
296 }
297
298 if (info) {
299 if (info->bsize) {
300 /* Round pagesize up to power of 2 */
301 hashp->BSHIFT = __log2(info->bsize);
302 hashp->BSIZE = 1 << hashp->BSHIFT;
303 if (hashp->BSIZE > MAX_BSIZE) {
304 errno = EINVAL;
305 return (NULL);
306 }
307 }
308 if (info->ffactor)
309 hashp->FFACTOR = info->ffactor;
310 if (info->hash)
311 hashp->hash = info->hash;
312 if (info->nelem)
313 nelem = info->nelem;
314 if (info->lorder) {
315 if (info->lorder != BIG_ENDIAN &&
316 info->lorder != LITTLE_ENDIAN) {
317 errno = EINVAL;
318 return (NULL);
319 }
320 hashp->LORDER = info->lorder;
321 }
322 }
323 /* init_htab should destroy the table and set errno if it fails */
324 if (init_htab(hashp, nelem))
325 return (NULL);
326 else
327 return (hashp);
328 }
329 /*
330 * This calls alloc_segs which may run out of memory. Alloc_segs will destroy
331 * the table and set errno, so we just pass the error information along.
332 *
333 * Returns 0 on No Error
334 */
335 static int
init_htab(HTAB * hashp,int nelem)336 init_htab(HTAB *hashp, int nelem)
337 {
338 int nbuckets, nsegs, l2;
339
340 /*
341 * Divide number of elements by the fill factor and determine a
342 * desired number of buckets. Allocate space for the next greater
343 * power of two number of buckets.
344 */
345 nelem = (nelem - 1) / hashp->FFACTOR + 1;
346
347 l2 = __log2(MAX(nelem, 2));
348 nbuckets = 1 << l2;
349
350 hashp->SPARES[l2] = l2 + 1;
351 hashp->SPARES[l2 + 1] = l2 + 1;
352 hashp->OVFL_POINT = l2;
353 hashp->LAST_FREED = 2;
354
355 /* First bitmap page is at: splitpoint l2 page offset 1 */
356 if (__ibitmap(hashp, OADDR_OF(l2, 1), l2 + 1, 0))
357 return (-1);
358
359 hashp->MAX_BUCKET = hashp->LOW_MASK = nbuckets - 1;
360 hashp->HIGH_MASK = (nbuckets << 1) - 1;
361 hashp->HDRPAGES = ((MAX(sizeof(HASHHDR), MINHDRSIZE) - 1) >>
362 hashp->BSHIFT) + 1;
363
364 nsegs = (nbuckets - 1) / hashp->SGSIZE + 1;
365 nsegs = 1 << __log2(nsegs);
366
367 if (nsegs > hashp->DSIZE)
368 hashp->DSIZE = nsegs;
369 return (alloc_segs(hashp, nsegs));
370 }
371
372 /********************** DESTROY/CLOSE ROUTINES ************************/
373
374 /*
375 * Flushes any changes to the file if necessary and destroys the hashp
376 * structure, freeing all allocated space.
377 */
378 static int
hdestroy(HTAB * hashp)379 hdestroy(HTAB *hashp)
380 {
381 int i, save_errno;
382
383 save_errno = 0;
384
385 #ifdef HASH_STATISTICS
386 (void)fprintf(stderr, "hdestroy: accesses %ld collisions %ld\n",
387 hash_accesses, hash_collisions);
388 (void)fprintf(stderr, "hdestroy: expansions %ld\n",
389 hash_expansions);
390 (void)fprintf(stderr, "hdestroy: overflows %ld\n",
391 hash_overflows);
392 (void)fprintf(stderr, "keys %ld maxp %d segmentcount %d\n",
393 hashp->NKEYS, hashp->MAX_BUCKET, hashp->nsegs);
394
395 for (i = 0; i < NCACHED; i++)
396 (void)fprintf(stderr,
397 "spares[%d] = %d\n", i, hashp->SPARES[i]);
398 #endif
399 /*
400 * Call on buffer manager to free buffers, and if required,
401 * write them to disk.
402 */
403 if (__buf_free(hashp, 1, hashp->save_file))
404 save_errno = errno;
405 if (hashp->dir) {
406 free(*hashp->dir); /* Free initial segments */
407 /* Free extra segments */
408 while (hashp->exsegs--)
409 free(hashp->dir[--hashp->nsegs]);
410 free(hashp->dir);
411 }
412 if (flush_meta(hashp) && !save_errno)
413 save_errno = errno;
414 /* Free Bigmaps */
415 for (i = 0; i < hashp->nmaps; i++)
416 if (hashp->mapp[i])
417 free(hashp->mapp[i]);
418 if (hashp->tmp_key)
419 free(hashp->tmp_key);
420 if (hashp->tmp_buf)
421 free(hashp->tmp_buf);
422
423 if (hashp->fp != -1) {
424 if (hashp->save_file)
425 (void)_fsync(hashp->fp);
426 (void)_close(hashp->fp);
427 }
428
429 free(hashp);
430
431 if (save_errno) {
432 errno = save_errno;
433 return (ERROR);
434 }
435 return (SUCCESS);
436 }
437 /*
438 * Write modified pages to disk
439 *
440 * Returns:
441 * 0 == OK
442 * -1 ERROR
443 */
444 static int
hash_sync(const DB * dbp,u_int32_t flags)445 hash_sync(const DB *dbp, u_int32_t flags)
446 {
447 HTAB *hashp;
448
449 if (flags != 0) {
450 errno = EINVAL;
451 return (ERROR);
452 }
453
454 if (!dbp)
455 return (ERROR);
456
457 hashp = (HTAB *)dbp->internal;
458 if (!hashp->save_file)
459 return (0);
460 if (__buf_free(hashp, 0, 1) || flush_meta(hashp))
461 return (ERROR);
462 if (hashp->fp != -1 && _fsync(hashp->fp) != 0)
463 return (ERROR);
464 hashp->new_file = 0;
465 return (0);
466 }
467
468 /*
469 * Returns:
470 * 0 == OK
471 * -1 indicates that errno should be set
472 */
473 static int
flush_meta(HTAB * hashp)474 flush_meta(HTAB *hashp)
475 {
476 HASHHDR *whdrp;
477 #if BYTE_ORDER == LITTLE_ENDIAN
478 HASHHDR whdr;
479 #endif
480 int fp, i, wsize;
481
482 if (!hashp->save_file)
483 return (0);
484 hashp->MAGIC = HASHMAGIC;
485 hashp->VERSION = HASHVERSION;
486 hashp->H_CHARKEY = hashp->hash(CHARKEY, sizeof(CHARKEY));
487
488 fp = hashp->fp;
489 whdrp = &hashp->hdr;
490 #if BYTE_ORDER == LITTLE_ENDIAN
491 whdrp = &whdr;
492 swap_header_copy(&hashp->hdr, whdrp);
493 #endif
494 if ((wsize = pwrite(fp, whdrp, sizeof(HASHHDR), (off_t)0)) == -1)
495 return (-1);
496 else
497 if (wsize != sizeof(HASHHDR)) {
498 errno = EFTYPE;
499 hashp->error = errno;
500 return (-1);
501 }
502 for (i = 0; i < NCACHED; i++)
503 if (hashp->mapp[i])
504 if (__put_page(hashp, (char *)hashp->mapp[i],
505 hashp->BITMAPS[i], 0, 1))
506 return (-1);
507 return (0);
508 }
509
510 /*******************************SEARCH ROUTINES *****************************/
511 /*
512 * All the access routines return
513 *
514 * Returns:
515 * 0 on SUCCESS
516 * 1 to indicate an external ERROR (i.e. key not found, etc)
517 * -1 to indicate an internal ERROR (i.e. out of memory, etc)
518 */
519 static int
hash_get(const DB * dbp,const DBT * key,DBT * data,u_int32_t flag)520 hash_get(const DB *dbp, const DBT *key, DBT *data, u_int32_t flag)
521 {
522 HTAB *hashp;
523
524 hashp = (HTAB *)dbp->internal;
525 if (flag) {
526 hashp->error = errno = EINVAL;
527 return (ERROR);
528 }
529 return (hash_access(hashp, HASH_GET, (DBT *)key, data));
530 }
531
532 static int
hash_put(const DB * dbp,DBT * key,const DBT * data,u_int32_t flag)533 hash_put(const DB *dbp, DBT *key, const DBT *data, u_int32_t flag)
534 {
535 HTAB *hashp;
536
537 hashp = (HTAB *)dbp->internal;
538 if (flag && flag != R_NOOVERWRITE) {
539 hashp->error = errno = EINVAL;
540 return (ERROR);
541 }
542 if ((hashp->flags & O_ACCMODE) == O_RDONLY) {
543 hashp->error = errno = EPERM;
544 return (ERROR);
545 }
546 return (hash_access(hashp, flag == R_NOOVERWRITE ?
547 HASH_PUTNEW : HASH_PUT, (DBT *)key, (DBT *)data));
548 }
549
550 static int
hash_delete(const DB * dbp,const DBT * key,u_int32_t flag)551 hash_delete(const DB *dbp, const DBT *key,
552 u_int32_t flag) /* Ignored */
553 {
554 HTAB *hashp;
555
556 hashp = (HTAB *)dbp->internal;
557 if (flag && flag != R_CURSOR) {
558 hashp->error = errno = EINVAL;
559 return (ERROR);
560 }
561 if ((hashp->flags & O_ACCMODE) == O_RDONLY) {
562 hashp->error = errno = EPERM;
563 return (ERROR);
564 }
565 return (hash_access(hashp, HASH_DELETE, (DBT *)key, NULL));
566 }
567
568 /*
569 * Assume that hashp has been set in wrapper routine.
570 */
571 static int
hash_access(HTAB * hashp,ACTION action,DBT * key,DBT * val)572 hash_access(HTAB *hashp, ACTION action, DBT *key, DBT *val)
573 {
574 BUFHEAD *rbufp;
575 BUFHEAD *bufp, *save_bufp;
576 u_int16_t *bp;
577 int n, ndx, off, size;
578 char *kp;
579 u_int16_t pageno;
580
581 #ifdef HASH_STATISTICS
582 hash_accesses++;
583 #endif
584
585 off = hashp->BSIZE;
586 size = key->size;
587 kp = (char *)key->data;
588 rbufp = __get_buf(hashp, __call_hash(hashp, kp, size), NULL, 0);
589 if (!rbufp)
590 return (ERROR);
591 save_bufp = rbufp;
592
593 /* Pin the bucket chain */
594 rbufp->flags |= BUF_PIN;
595 for (bp = (u_int16_t *)rbufp->page, n = *bp++, ndx = 1; ndx < n;)
596 if (bp[1] >= REAL_KEY) {
597 /* Real key/data pair */
598 if (size == off - *bp &&
599 memcmp(kp, rbufp->page + *bp, size) == 0)
600 goto found;
601 off = bp[1];
602 #ifdef HASH_STATISTICS
603 hash_collisions++;
604 #endif
605 bp += 2;
606 ndx += 2;
607 } else if (bp[1] == OVFLPAGE) {
608 rbufp = __get_buf(hashp, *bp, rbufp, 0);
609 if (!rbufp) {
610 save_bufp->flags &= ~BUF_PIN;
611 return (ERROR);
612 }
613 /* FOR LOOP INIT */
614 bp = (u_int16_t *)rbufp->page;
615 n = *bp++;
616 ndx = 1;
617 off = hashp->BSIZE;
618 } else if (bp[1] < REAL_KEY) {
619 if ((ndx =
620 __find_bigpair(hashp, rbufp, ndx, kp, size)) > 0)
621 goto found;
622 if (ndx == -2) {
623 bufp = rbufp;
624 if (!(pageno =
625 __find_last_page(hashp, &bufp))) {
626 ndx = 0;
627 rbufp = bufp;
628 break; /* FOR */
629 }
630 rbufp = __get_buf(hashp, pageno, bufp, 0);
631 if (!rbufp) {
632 save_bufp->flags &= ~BUF_PIN;
633 return (ERROR);
634 }
635 /* FOR LOOP INIT */
636 bp = (u_int16_t *)rbufp->page;
637 n = *bp++;
638 ndx = 1;
639 off = hashp->BSIZE;
640 } else {
641 save_bufp->flags &= ~BUF_PIN;
642 return (ERROR);
643 }
644 }
645
646 /* Not found */
647 switch (action) {
648 case HASH_PUT:
649 case HASH_PUTNEW:
650 if (__addel(hashp, rbufp, key, val)) {
651 save_bufp->flags &= ~BUF_PIN;
652 return (ERROR);
653 } else {
654 save_bufp->flags &= ~BUF_PIN;
655 return (SUCCESS);
656 }
657 case HASH_GET:
658 case HASH_DELETE:
659 default:
660 save_bufp->flags &= ~BUF_PIN;
661 return (ABNORMAL);
662 }
663
664 found:
665 switch (action) {
666 case HASH_PUTNEW:
667 save_bufp->flags &= ~BUF_PIN;
668 return (ABNORMAL);
669 case HASH_GET:
670 bp = (u_int16_t *)rbufp->page;
671 if (bp[ndx + 1] < REAL_KEY) {
672 if (__big_return(hashp, rbufp, ndx, val, 0))
673 return (ERROR);
674 } else {
675 val->data = (u_char *)rbufp->page + (int)bp[ndx + 1];
676 val->size = bp[ndx] - bp[ndx + 1];
677 }
678 break;
679 case HASH_PUT:
680 if ((__delpair(hashp, rbufp, ndx)) ||
681 (__addel(hashp, rbufp, key, val))) {
682 save_bufp->flags &= ~BUF_PIN;
683 return (ERROR);
684 }
685 break;
686 case HASH_DELETE:
687 if (__delpair(hashp, rbufp, ndx))
688 return (ERROR);
689 break;
690 default:
691 abort();
692 }
693 save_bufp->flags &= ~BUF_PIN;
694 return (SUCCESS);
695 }
696
697 static int
hash_seq(const DB * dbp,DBT * key,DBT * data,u_int32_t flag)698 hash_seq(const DB *dbp, DBT *key, DBT *data, u_int32_t flag)
699 {
700 u_int32_t bucket;
701 BUFHEAD *bufp;
702 HTAB *hashp;
703 u_int16_t *bp, ndx;
704
705 hashp = (HTAB *)dbp->internal;
706 if (flag && flag != R_FIRST && flag != R_NEXT) {
707 hashp->error = errno = EINVAL;
708 return (ERROR);
709 }
710 #ifdef HASH_STATISTICS
711 hash_accesses++;
712 #endif
713 if ((hashp->cbucket < 0) || (flag == R_FIRST)) {
714 hashp->cbucket = 0;
715 hashp->cndx = 1;
716 hashp->cpage = NULL;
717 }
718 next_bucket:
719 for (bp = NULL; !bp || !bp[0]; ) {
720 if (!(bufp = hashp->cpage)) {
721 for (bucket = hashp->cbucket;
722 bucket <= hashp->MAX_BUCKET;
723 bucket++, hashp->cndx = 1) {
724 bufp = __get_buf(hashp, bucket, NULL, 0);
725 if (!bufp)
726 return (ERROR);
727 hashp->cpage = bufp;
728 bp = (u_int16_t *)bufp->page;
729 if (bp[0])
730 break;
731 }
732 hashp->cbucket = bucket;
733 if ((u_int32_t)hashp->cbucket > hashp->MAX_BUCKET) {
734 hashp->cbucket = -1;
735 return (ABNORMAL);
736 }
737 } else {
738 bp = (u_int16_t *)hashp->cpage->page;
739 if (flag == R_NEXT || flag == 0) {
740 hashp->cndx += 2;
741 if (hashp->cndx > bp[0]) {
742 hashp->cpage = NULL;
743 hashp->cbucket++;
744 hashp->cndx = 1;
745 goto next_bucket;
746 }
747 }
748 }
749
750 #ifdef DEBUG
751 assert(bp);
752 assert(bufp);
753 #endif
754 while (bp[hashp->cndx + 1] == OVFLPAGE) {
755 bufp = hashp->cpage =
756 __get_buf(hashp, bp[hashp->cndx], bufp, 0);
757 if (!bufp)
758 return (ERROR);
759 bp = (u_int16_t *)(bufp->page);
760 hashp->cndx = 1;
761 }
762 if (!bp[0]) {
763 hashp->cpage = NULL;
764 ++hashp->cbucket;
765 }
766 }
767 ndx = hashp->cndx;
768 if (bp[ndx + 1] < REAL_KEY) {
769 if (__big_keydata(hashp, bufp, key, data, 1))
770 return (ERROR);
771 } else {
772 if (hashp->cpage == NULL)
773 return (ERROR);
774 key->data = (u_char *)hashp->cpage->page + bp[ndx];
775 key->size = (ndx > 1 ? bp[ndx - 1] : hashp->BSIZE) - bp[ndx];
776 data->data = (u_char *)hashp->cpage->page + bp[ndx + 1];
777 data->size = bp[ndx] - bp[ndx + 1];
778 }
779 return (SUCCESS);
780 }
781
782 /********************************* UTILITIES ************************/
783
784 /*
785 * Returns:
786 * 0 ==> OK
787 * -1 ==> Error
788 */
789 int
__expand_table(HTAB * hashp)790 __expand_table(HTAB *hashp)
791 {
792 u_int32_t old_bucket, new_bucket;
793 int dirsize, new_segnum, spare_ndx;
794
795 #ifdef HASH_STATISTICS
796 hash_expansions++;
797 #endif
798 new_bucket = ++hashp->MAX_BUCKET;
799 old_bucket = (hashp->MAX_BUCKET & hashp->LOW_MASK);
800
801 new_segnum = new_bucket >> hashp->SSHIFT;
802
803 /* Check if we need a new segment */
804 if (new_segnum >= hashp->nsegs) {
805 /* Check if we need to expand directory */
806 if (new_segnum >= hashp->DSIZE) {
807 /* Reallocate directory */
808 dirsize = hashp->DSIZE * sizeof(SEGMENT *);
809 if (!hash_realloc(&hashp->dir, dirsize, dirsize << 1))
810 return (-1);
811 hashp->DSIZE = dirsize << 1;
812 }
813 if ((hashp->dir[new_segnum] =
814 calloc(hashp->SGSIZE, sizeof(SEGMENT))) == NULL)
815 return (-1);
816 hashp->exsegs++;
817 hashp->nsegs++;
818 }
819 /*
820 * If the split point is increasing (MAX_BUCKET's log base 2
821 * * increases), we need to copy the current contents of the spare
822 * split bucket to the next bucket.
823 */
824 spare_ndx = __log2(hashp->MAX_BUCKET + 1);
825 if (spare_ndx > hashp->OVFL_POINT) {
826 hashp->SPARES[spare_ndx] = hashp->SPARES[hashp->OVFL_POINT];
827 hashp->OVFL_POINT = spare_ndx;
828 }
829
830 if (new_bucket > hashp->HIGH_MASK) {
831 /* Starting a new doubling */
832 hashp->LOW_MASK = hashp->HIGH_MASK;
833 hashp->HIGH_MASK = new_bucket | hashp->LOW_MASK;
834 }
835 /* Relocate records to the new bucket */
836 return (__split_page(hashp, old_bucket, new_bucket));
837 }
838
839 /*
840 * If realloc guarantees that the pointer is not destroyed if the realloc
841 * fails, then this routine can go away.
842 */
843 static void *
hash_realloc(SEGMENT ** p_ptr,int oldsize,int newsize)844 hash_realloc(SEGMENT **p_ptr, int oldsize, int newsize)
845 {
846 void *p;
847
848 if ( (p = malloc(newsize)) ) {
849 memmove(p, *p_ptr, oldsize);
850 memset((char *)p + oldsize, 0, newsize - oldsize);
851 free(*p_ptr);
852 *p_ptr = p;
853 }
854 return (p);
855 }
856
857 u_int32_t
__call_hash(HTAB * hashp,char * k,int len)858 __call_hash(HTAB *hashp, char *k, int len)
859 {
860 unsigned int n, bucket;
861
862 n = hashp->hash(k, len);
863 bucket = n & hashp->HIGH_MASK;
864 if (bucket > hashp->MAX_BUCKET)
865 bucket = bucket & hashp->LOW_MASK;
866 return (bucket);
867 }
868
869 /*
870 * Allocate segment table. On error, destroy the table and set errno.
871 *
872 * Returns 0 on success
873 */
874 static int
alloc_segs(HTAB * hashp,int nsegs)875 alloc_segs(HTAB *hashp, int nsegs)
876 {
877 int i;
878 SEGMENT store;
879
880 int save_errno;
881
882 if ((hashp->dir =
883 calloc(hashp->DSIZE, sizeof(SEGMENT *))) == NULL) {
884 save_errno = errno;
885 (void)hdestroy(hashp);
886 errno = save_errno;
887 return (-1);
888 }
889 hashp->nsegs = nsegs;
890 if (nsegs == 0)
891 return (0);
892 /* Allocate segments */
893 if ((store = calloc(nsegs << hashp->SSHIFT, sizeof(SEGMENT))) == NULL) {
894 save_errno = errno;
895 (void)hdestroy(hashp);
896 errno = save_errno;
897 return (-1);
898 }
899 for (i = 0; i < nsegs; i++)
900 hashp->dir[i] = &store[i << hashp->SSHIFT];
901 return (0);
902 }
903
904 #if BYTE_ORDER == LITTLE_ENDIAN
905 /*
906 * Hashp->hdr needs to be byteswapped.
907 */
908 static void
swap_header_copy(HASHHDR * srcp,HASHHDR * destp)909 swap_header_copy(HASHHDR *srcp, HASHHDR *destp)
910 {
911 int i;
912
913 P_32_COPY(srcp->magic, destp->magic);
914 P_32_COPY(srcp->version, destp->version);
915 P_32_COPY(srcp->lorder, destp->lorder);
916 P_32_COPY(srcp->bsize, destp->bsize);
917 P_32_COPY(srcp->bshift, destp->bshift);
918 P_32_COPY(srcp->dsize, destp->dsize);
919 P_32_COPY(srcp->ssize, destp->ssize);
920 P_32_COPY(srcp->sshift, destp->sshift);
921 P_32_COPY(srcp->ovfl_point, destp->ovfl_point);
922 P_32_COPY(srcp->last_freed, destp->last_freed);
923 P_32_COPY(srcp->max_bucket, destp->max_bucket);
924 P_32_COPY(srcp->high_mask, destp->high_mask);
925 P_32_COPY(srcp->low_mask, destp->low_mask);
926 P_32_COPY(srcp->ffactor, destp->ffactor);
927 P_32_COPY(srcp->nkeys, destp->nkeys);
928 P_32_COPY(srcp->hdrpages, destp->hdrpages);
929 P_32_COPY(srcp->h_charkey, destp->h_charkey);
930 for (i = 0; i < NCACHED; i++) {
931 P_32_COPY(srcp->spares[i], destp->spares[i]);
932 P_16_COPY(srcp->bitmaps[i], destp->bitmaps[i]);
933 }
934 }
935
936 static void
swap_header(HTAB * hashp)937 swap_header(HTAB *hashp)
938 {
939 HASHHDR *hdrp;
940 int i;
941
942 hdrp = &hashp->hdr;
943
944 M_32_SWAP(hdrp->magic);
945 M_32_SWAP(hdrp->version);
946 M_32_SWAP(hdrp->lorder);
947 M_32_SWAP(hdrp->bsize);
948 M_32_SWAP(hdrp->bshift);
949 M_32_SWAP(hdrp->dsize);
950 M_32_SWAP(hdrp->ssize);
951 M_32_SWAP(hdrp->sshift);
952 M_32_SWAP(hdrp->ovfl_point);
953 M_32_SWAP(hdrp->last_freed);
954 M_32_SWAP(hdrp->max_bucket);
955 M_32_SWAP(hdrp->high_mask);
956 M_32_SWAP(hdrp->low_mask);
957 M_32_SWAP(hdrp->ffactor);
958 M_32_SWAP(hdrp->nkeys);
959 M_32_SWAP(hdrp->hdrpages);
960 M_32_SWAP(hdrp->h_charkey);
961 for (i = 0; i < NCACHED; i++) {
962 M_32_SWAP(hdrp->spares[i]);
963 M_16_SWAP(hdrp->bitmaps[i]);
964 }
965 }
966 #endif
967