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