1 /*-
2 * Copyright (c) 1990, 1993, 1994
3 * The Regents of the University of California. All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Margo Seltzer.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 4. Neither the name of the University nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33 #if defined(LIBC_SCCS) && !defined(lint)
34 static char sccsid[] = "@(#)hash.c 8.9 (Berkeley) 6/16/94";
35 #endif /* LIBC_SCCS and not lint */
36 #include <sys/cdefs.h>
37 __FBSDID("$FreeBSD$");
38
39 #include "namespace.h"
40 #include <sys/param.h>
41 #include <sys/stat.h>
42
43 #include <errno.h>
44 #include <fcntl.h>
45 #include <stdio.h>
46 #include <stdlib.h>
47 #include <string.h>
48 #include <unistd.h>
49 #ifdef DEBUG
50 #include <assert.h>
51 #endif
52 #include "un-namespace.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 *, u_int32_t);
64 static int hash_fd(const DB *);
65 static int hash_get(const DB *, const DBT *, DBT *, u_int32_t);
66 static int hash_put(const DB *, DBT *, const DBT *, u_int32_t);
67 static void *hash_realloc(SEGMENT **, int, int);
68 static int hash_seq(const DB *, DBT *, DBT *, u_int32_t);
69 static int hash_sync(const DB *, u_int32_t);
70 static int hdestroy(HTAB *);
71 static HTAB *init_hash(HTAB *, const char *, const HASHINFO *);
72 static int init_htab(HTAB *, int);
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,int mode,const HASHINFO * info,int dflags)97 __hash_open(const char *file, int flags, int mode,
98 const HASHINFO *info, /* Special directives for create */
99 int dflags)
100 {
101 HTAB *hashp;
102 struct stat statbuf;
103 DB *dbp;
104 int bpages, hdrsize, new_table, nsegs, save_errno;
105
106 if ((flags & O_ACCMODE) == O_WRONLY) {
107 errno = EINVAL;
108 return (NULL);
109 }
110
111 if (!(hashp = (HTAB *)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 if (file) {
124 if ((hashp->fp = _open(file, flags | O_CLOEXEC, mode)) == -1)
125 RETURN_ERROR(errno, error0);
126 new_table = _fstat(hashp->fp, &statbuf) == 0 &&
127 statbuf.st_size == 0 && (flags & O_ACCMODE) != O_RDONLY;
128 } else
129 new_table = 1;
130
131 if (new_table) {
132 if (!(hashp = init_hash(hashp, file, info)))
133 RETURN_ERROR(errno, error1);
134 } else {
135 /* Table already exists */
136 if (info && info->hash)
137 hashp->hash = info->hash;
138 else
139 hashp->hash = __default_hash;
140
141 hdrsize = _read(hashp->fp, &hashp->hdr, sizeof(HASHHDR));
142 #if BYTE_ORDER == LITTLE_ENDIAN
143 swap_header(hashp);
144 #endif
145 if (hdrsize == -1)
146 RETURN_ERROR(errno, error1);
147 if (hdrsize != sizeof(HASHHDR))
148 RETURN_ERROR(EFTYPE, error1);
149 /* Verify file type, versions and hash function */
150 if (hashp->MAGIC != HASHMAGIC)
151 RETURN_ERROR(EFTYPE, error1);
152 #define OLDHASHVERSION 1
153 if (hashp->VERSION != HASHVERSION &&
154 hashp->VERSION != OLDHASHVERSION)
155 RETURN_ERROR(EFTYPE, error1);
156 if ((int32_t)hashp->hash(CHARKEY, sizeof(CHARKEY)) != hashp->H_CHARKEY)
157 RETURN_ERROR(EFTYPE, error1);
158 /*
159 * Figure out how many segments we need. Max_Bucket is the
160 * maximum bucket number, so the number of buckets is
161 * max_bucket + 1.
162 */
163 nsegs = howmany(hashp->MAX_BUCKET + 1, hashp->SGSIZE);
164 if (alloc_segs(hashp, nsegs))
165 /*
166 * If alloc_segs fails, table will have been destroyed
167 * and errno will have been set.
168 */
169 return (NULL);
170 /* Read in bitmaps */
171 bpages = (hashp->SPARES[hashp->OVFL_POINT] +
172 (hashp->BSIZE << BYTE_SHIFT) - 1) >>
173 (hashp->BSHIFT + BYTE_SHIFT);
174
175 hashp->nmaps = bpages;
176 (void)memset(&hashp->mapp[0], 0, bpages * sizeof(u_int32_t *));
177 }
178
179 /* Initialize Buffer Manager */
180 if (info && info->cachesize)
181 __buf_init(hashp, info->cachesize);
182 else
183 __buf_init(hashp, DEF_BUFSIZE);
184
185 hashp->new_file = new_table;
186 hashp->save_file = file && (hashp->flags & O_RDWR);
187 hashp->cbucket = -1;
188 if (!(dbp = (DB *)malloc(sizeof(DB)))) {
189 save_errno = errno;
190 hdestroy(hashp);
191 errno = save_errno;
192 return (NULL);
193 }
194 dbp->internal = hashp;
195 dbp->close = hash_close;
196 dbp->del = hash_delete;
197 dbp->fd = hash_fd;
198 dbp->get = hash_get;
199 dbp->put = hash_put;
200 dbp->seq = hash_seq;
201 dbp->sync = hash_sync;
202 dbp->type = DB_HASH;
203
204 #ifdef DEBUG
205 (void)fprintf(stderr,
206 "%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",
207 "init_htab:",
208 "TABLE POINTER ", hashp,
209 "BUCKET SIZE ", hashp->BSIZE,
210 "BUCKET SHIFT ", hashp->BSHIFT,
211 "DIRECTORY SIZE ", hashp->DSIZE,
212 "SEGMENT SIZE ", hashp->SGSIZE,
213 "SEGMENT SHIFT ", hashp->SSHIFT,
214 "FILL FACTOR ", hashp->FFACTOR,
215 "MAX BUCKET ", hashp->MAX_BUCKET,
216 "OVFL POINT ", hashp->OVFL_POINT,
217 "LAST FREED ", hashp->LAST_FREED,
218 "HIGH MASK ", hashp->HIGH_MASK,
219 "LOW MASK ", hashp->LOW_MASK,
220 "NSEGS ", hashp->nsegs,
221 "NKEYS ", hashp->NKEYS);
222 #endif
223 #ifdef HASH_STATISTICS
224 hash_overflows = hash_accesses = hash_collisions = hash_expansions = 0;
225 #endif
226 return (dbp);
227
228 error1:
229 if (hashp != NULL)
230 (void)_close(hashp->fp);
231
232 error0:
233 free(hashp);
234 errno = save_errno;
235 return (NULL);
236 }
237
238 static int
hash_close(DB * dbp)239 hash_close(DB *dbp)
240 {
241 HTAB *hashp;
242 int retval;
243
244 if (!dbp)
245 return (ERROR);
246
247 hashp = (HTAB *)dbp->internal;
248 retval = hdestroy(hashp);
249 free(dbp);
250 return (retval);
251 }
252
253 static int
hash_fd(const DB * dbp)254 hash_fd(const DB *dbp)
255 {
256 HTAB *hashp;
257
258 if (!dbp)
259 return (ERROR);
260
261 hashp = (HTAB *)dbp->internal;
262 if (hashp->fp == -1) {
263 errno = ENOENT;
264 return (-1);
265 }
266 return (hashp->fp);
267 }
268
269 /************************** LOCAL CREATION ROUTINES **********************/
270 static HTAB *
init_hash(HTAB * hashp,const char * file,const HASHINFO * info)271 init_hash(HTAB *hashp, const char *file, const HASHINFO *info)
272 {
273 struct stat statbuf;
274 int nelem;
275
276 nelem = 1;
277 hashp->NKEYS = 0;
278 hashp->LORDER = BYTE_ORDER;
279 hashp->BSIZE = DEF_BUCKET_SIZE;
280 hashp->BSHIFT = DEF_BUCKET_SHIFT;
281 hashp->SGSIZE = DEF_SEGSIZE;
282 hashp->SSHIFT = DEF_SEGSIZE_SHIFT;
283 hashp->DSIZE = DEF_DIRSIZE;
284 hashp->FFACTOR = DEF_FFACTOR;
285 hashp->hash = __default_hash;
286 memset(hashp->SPARES, 0, sizeof(hashp->SPARES));
287 memset(hashp->BITMAPS, 0, sizeof (hashp->BITMAPS));
288
289 /* Fix bucket size to be optimal for file system */
290 if (file != NULL) {
291 if (stat(file, &statbuf))
292 return (NULL);
293 hashp->BSIZE = statbuf.st_blksize;
294 if (hashp->BSIZE > MAX_BSIZE)
295 hashp->BSIZE = MAX_BSIZE;
296 hashp->BSHIFT = __log2(hashp->BSIZE);
297 }
298
299 if (info) {
300 if (info->bsize) {
301 /* Round pagesize up to power of 2 */
302 hashp->BSHIFT = __log2(info->bsize);
303 hashp->BSIZE = 1 << hashp->BSHIFT;
304 if (hashp->BSIZE > MAX_BSIZE) {
305 errno = EINVAL;
306 return (NULL);
307 }
308 }
309 if (info->ffactor)
310 hashp->FFACTOR = info->ffactor;
311 if (info->hash)
312 hashp->hash = info->hash;
313 if (info->nelem)
314 nelem = info->nelem;
315 if (info->lorder) {
316 if (info->lorder != BIG_ENDIAN &&
317 info->lorder != LITTLE_ENDIAN) {
318 errno = EINVAL;
319 return (NULL);
320 }
321 hashp->LORDER = info->lorder;
322 }
323 }
324 /* init_htab should destroy the table and set errno if it fails */
325 if (init_htab(hashp, nelem))
326 return (NULL);
327 else
328 return (hashp);
329 }
330 /*
331 * This calls alloc_segs which may run out of memory. Alloc_segs will destroy
332 * the table and set errno, so we just pass the error information along.
333 *
334 * Returns 0 on No Error
335 */
336 static int
init_htab(HTAB * hashp,int nelem)337 init_htab(HTAB *hashp, int nelem)
338 {
339 int nbuckets, nsegs, l2;
340
341 /*
342 * Divide number of elements by the fill factor and determine a
343 * desired number of buckets. Allocate space for the next greater
344 * power of two number of buckets.
345 */
346 nelem = (nelem - 1) / hashp->FFACTOR + 1;
347
348 l2 = __log2(MAX(nelem, 2));
349 nbuckets = 1 << l2;
350
351 hashp->SPARES[l2] = l2 + 1;
352 hashp->SPARES[l2 + 1] = l2 + 1;
353 hashp->OVFL_POINT = l2;
354 hashp->LAST_FREED = 2;
355
356 /* First bitmap page is at: splitpoint l2 page offset 1 */
357 if (__ibitmap(hashp, OADDR_OF(l2, 1), l2 + 1, 0))
358 return (-1);
359
360 hashp->MAX_BUCKET = hashp->LOW_MASK = nbuckets - 1;
361 hashp->HIGH_MASK = (nbuckets << 1) - 1;
362 hashp->HDRPAGES = ((MAX(sizeof(HASHHDR), MINHDRSIZE) - 1) >>
363 hashp->BSHIFT) + 1;
364
365 nsegs = (nbuckets - 1) / hashp->SGSIZE + 1;
366 nsegs = 1 << __log2(nsegs);
367
368 if (nsegs > hashp->DSIZE)
369 hashp->DSIZE = nsegs;
370 return (alloc_segs(hashp, nsegs));
371 }
372
373 /********************** DESTROY/CLOSE ROUTINES ************************/
374
375 /*
376 * Flushes any changes to the file if necessary and destroys the hashp
377 * structure, freeing all allocated space.
378 */
379 static int
hdestroy(HTAB * hashp)380 hdestroy(HTAB *hashp)
381 {
382 int i, save_errno;
383
384 save_errno = 0;
385
386 #ifdef HASH_STATISTICS
387 (void)fprintf(stderr, "hdestroy: accesses %ld collisions %ld\n",
388 hash_accesses, hash_collisions);
389 (void)fprintf(stderr, "hdestroy: expansions %ld\n",
390 hash_expansions);
391 (void)fprintf(stderr, "hdestroy: overflows %ld\n",
392 hash_overflows);
393 (void)fprintf(stderr, "keys %ld maxp %d segmentcount %d\n",
394 hashp->NKEYS, hashp->MAX_BUCKET, hashp->nsegs);
395
396 for (i = 0; i < NCACHED; i++)
397 (void)fprintf(stderr,
398 "spares[%d] = %d\n", i, hashp->SPARES[i]);
399 #endif
400 /*
401 * Call on buffer manager to free buffers, and if required,
402 * write them to disk.
403 */
404 if (__buf_free(hashp, 1, hashp->save_file))
405 save_errno = errno;
406 if (hashp->dir) {
407 free(*hashp->dir); /* Free initial segments */
408 /* Free extra segments */
409 while (hashp->exsegs--)
410 free(hashp->dir[--hashp->nsegs]);
411 free(hashp->dir);
412 }
413 if (flush_meta(hashp) && !save_errno)
414 save_errno = errno;
415 /* Free Bigmaps */
416 for (i = 0; i < hashp->nmaps; i++)
417 if (hashp->mapp[i])
418 free(hashp->mapp[i]);
419 if (hashp->tmp_key)
420 free(hashp->tmp_key);
421 if (hashp->tmp_buf)
422 free(hashp->tmp_buf);
423
424 if (hashp->fp != -1) {
425 if (hashp->save_file)
426 (void)_fsync(hashp->fp);
427 (void)_close(hashp->fp);
428 }
429
430 free(hashp);
431
432 if (save_errno) {
433 errno = save_errno;
434 return (ERROR);
435 }
436 return (SUCCESS);
437 }
438 /*
439 * Write modified pages to disk
440 *
441 * Returns:
442 * 0 == OK
443 * -1 ERROR
444 */
445 static int
hash_sync(const DB * dbp,u_int32_t flags)446 hash_sync(const DB *dbp, u_int32_t flags)
447 {
448 HTAB *hashp;
449
450 if (flags != 0) {
451 errno = EINVAL;
452 return (ERROR);
453 }
454
455 if (!dbp)
456 return (ERROR);
457
458 hashp = (HTAB *)dbp->internal;
459 if (!hashp->save_file)
460 return (0);
461 if (__buf_free(hashp, 0, 1) || flush_meta(hashp))
462 return (ERROR);
463 if (hashp->fp != -1 && _fsync(hashp->fp) != 0)
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, wsize;
482
483 if (!hashp->save_file)
484 return (0);
485 hashp->MAGIC = HASHMAGIC;
486 hashp->VERSION = HASHVERSION;
487 hashp->H_CHARKEY = hashp->hash(CHARKEY, sizeof(CHARKEY));
488
489 fp = hashp->fp;
490 whdrp = &hashp->hdr;
491 #if BYTE_ORDER == LITTLE_ENDIAN
492 whdrp = &whdr;
493 swap_header_copy(&hashp->hdr, whdrp);
494 #endif
495 if ((wsize = pwrite(fp, whdrp, sizeof(HASHHDR), (off_t)0)) == -1)
496 return (-1);
497 else
498 if (wsize != sizeof(HASHHDR)) {
499 errno = EFTYPE;
500 hashp->error = errno;
501 return (-1);
502 }
503 for (i = 0; i < NCACHED; i++)
504 if (hashp->mapp[i])
505 if (__put_page(hashp, (char *)hashp->mapp[i],
506 hashp->BITMAPS[i], 0, 1))
507 return (-1);
508 return (0);
509 }
510
511 /*******************************SEARCH ROUTINES *****************************/
512 /*
513 * All the access routines return
514 *
515 * Returns:
516 * 0 on SUCCESS
517 * 1 to indicate an external ERROR (i.e. key not found, etc)
518 * -1 to indicate an internal ERROR (i.e. out of memory, etc)
519 */
520 static int
hash_get(const DB * dbp,const DBT * key,DBT * data,u_int32_t flag)521 hash_get(const DB *dbp, const DBT *key, DBT *data, u_int32_t flag)
522 {
523 HTAB *hashp;
524
525 hashp = (HTAB *)dbp->internal;
526 if (flag) {
527 hashp->error = errno = EINVAL;
528 return (ERROR);
529 }
530 return (hash_access(hashp, HASH_GET, (DBT *)key, data));
531 }
532
533 static int
hash_put(const DB * dbp,DBT * key,const DBT * data,u_int32_t flag)534 hash_put(const DB *dbp, DBT *key, const DBT *data, u_int32_t flag)
535 {
536 HTAB *hashp;
537
538 hashp = (HTAB *)dbp->internal;
539 if (flag && flag != R_NOOVERWRITE) {
540 hashp->error = errno = EINVAL;
541 return (ERROR);
542 }
543 if ((hashp->flags & O_ACCMODE) == O_RDONLY) {
544 hashp->error = errno = EPERM;
545 return (ERROR);
546 }
547 return (hash_access(hashp, flag == R_NOOVERWRITE ?
548 HASH_PUTNEW : HASH_PUT, (DBT *)key, (DBT *)data));
549 }
550
551 static int
hash_delete(const DB * dbp,const DBT * key,u_int32_t flag)552 hash_delete(const DB *dbp, const DBT *key,
553 u_int32_t flag) /* Ignored */
554 {
555 HTAB *hashp;
556
557 hashp = (HTAB *)dbp->internal;
558 if (flag && flag != R_CURSOR) {
559 hashp->error = errno = EINVAL;
560 return (ERROR);
561 }
562 if ((hashp->flags & O_ACCMODE) == O_RDONLY) {
563 hashp->error = errno = EPERM;
564 return (ERROR);
565 }
566 return (hash_access(hashp, HASH_DELETE, (DBT *)key, NULL));
567 }
568
569 /*
570 * Assume that hashp has been set in wrapper routine.
571 */
572 static int
hash_access(HTAB * hashp,ACTION action,DBT * key,DBT * val)573 hash_access(HTAB *hashp, ACTION action, DBT *key, DBT *val)
574 {
575 BUFHEAD *rbufp;
576 BUFHEAD *bufp, *save_bufp;
577 u_int16_t *bp;
578 int n, ndx, off, size;
579 char *kp;
580 u_int16_t pageno;
581
582 #ifdef HASH_STATISTICS
583 hash_accesses++;
584 #endif
585
586 off = hashp->BSIZE;
587 size = key->size;
588 kp = (char *)key->data;
589 rbufp = __get_buf(hashp, __call_hash(hashp, kp, size), NULL, 0);
590 if (!rbufp)
591 return (ERROR);
592 save_bufp = rbufp;
593
594 /* Pin the bucket chain */
595 rbufp->flags |= BUF_PIN;
596 for (bp = (u_int16_t *)rbufp->page, n = *bp++, ndx = 1; ndx < n;)
597 if (bp[1] >= REAL_KEY) {
598 /* Real key/data pair */
599 if (size == off - *bp &&
600 memcmp(kp, rbufp->page + *bp, size) == 0)
601 goto found;
602 off = bp[1];
603 #ifdef HASH_STATISTICS
604 hash_collisions++;
605 #endif
606 bp += 2;
607 ndx += 2;
608 } else if (bp[1] == OVFLPAGE) {
609 rbufp = __get_buf(hashp, *bp, rbufp, 0);
610 if (!rbufp) {
611 save_bufp->flags &= ~BUF_PIN;
612 return (ERROR);
613 }
614 /* FOR LOOP INIT */
615 bp = (u_int16_t *)rbufp->page;
616 n = *bp++;
617 ndx = 1;
618 off = hashp->BSIZE;
619 } else if (bp[1] < REAL_KEY) {
620 if ((ndx =
621 __find_bigpair(hashp, rbufp, ndx, kp, size)) > 0)
622 goto found;
623 if (ndx == -2) {
624 bufp = rbufp;
625 if (!(pageno =
626 __find_last_page(hashp, &bufp))) {
627 ndx = 0;
628 rbufp = bufp;
629 break; /* FOR */
630 }
631 rbufp = __get_buf(hashp, pageno, bufp, 0);
632 if (!rbufp) {
633 save_bufp->flags &= ~BUF_PIN;
634 return (ERROR);
635 }
636 /* FOR LOOP INIT */
637 bp = (u_int16_t *)rbufp->page;
638 n = *bp++;
639 ndx = 1;
640 off = hashp->BSIZE;
641 } else {
642 save_bufp->flags &= ~BUF_PIN;
643 return (ERROR);
644 }
645 }
646
647 /* Not found */
648 switch (action) {
649 case HASH_PUT:
650 case HASH_PUTNEW:
651 if (__addel(hashp, rbufp, key, val)) {
652 save_bufp->flags &= ~BUF_PIN;
653 return (ERROR);
654 } else {
655 save_bufp->flags &= ~BUF_PIN;
656 return (SUCCESS);
657 }
658 case HASH_GET:
659 case HASH_DELETE:
660 default:
661 save_bufp->flags &= ~BUF_PIN;
662 return (ABNORMAL);
663 }
664
665 found:
666 switch (action) {
667 case HASH_PUTNEW:
668 save_bufp->flags &= ~BUF_PIN;
669 return (ABNORMAL);
670 case HASH_GET:
671 bp = (u_int16_t *)rbufp->page;
672 if (bp[ndx + 1] < REAL_KEY) {
673 if (__big_return(hashp, rbufp, ndx, val, 0))
674 return (ERROR);
675 } else {
676 val->data = (u_char *)rbufp->page + (int)bp[ndx + 1];
677 val->size = bp[ndx] - bp[ndx + 1];
678 }
679 break;
680 case HASH_PUT:
681 if ((__delpair(hashp, rbufp, ndx)) ||
682 (__addel(hashp, rbufp, key, val))) {
683 save_bufp->flags &= ~BUF_PIN;
684 return (ERROR);
685 }
686 break;
687 case HASH_DELETE:
688 if (__delpair(hashp, rbufp, ndx))
689 return (ERROR);
690 break;
691 default:
692 abort();
693 }
694 save_bufp->flags &= ~BUF_PIN;
695 return (SUCCESS);
696 }
697
698 static int
hash_seq(const DB * dbp,DBT * key,DBT * data,u_int32_t flag)699 hash_seq(const DB *dbp, DBT *key, DBT *data, u_int32_t flag)
700 {
701 u_int32_t bucket;
702 BUFHEAD *bufp;
703 HTAB *hashp;
704 u_int16_t *bp, ndx;
705
706 hashp = (HTAB *)dbp->internal;
707 if (flag && flag != R_FIRST && flag != R_NEXT) {
708 hashp->error = errno = EINVAL;
709 return (ERROR);
710 }
711 #ifdef HASH_STATISTICS
712 hash_accesses++;
713 #endif
714 if ((hashp->cbucket < 0) || (flag == R_FIRST)) {
715 hashp->cbucket = 0;
716 hashp->cndx = 1;
717 hashp->cpage = NULL;
718 }
719 next_bucket:
720 for (bp = NULL; !bp || !bp[0]; ) {
721 if (!(bufp = hashp->cpage)) {
722 for (bucket = hashp->cbucket;
723 bucket <= hashp->MAX_BUCKET;
724 bucket++, hashp->cndx = 1) {
725 bufp = __get_buf(hashp, bucket, NULL, 0);
726 if (!bufp)
727 return (ERROR);
728 hashp->cpage = bufp;
729 bp = (u_int16_t *)bufp->page;
730 if (bp[0])
731 break;
732 }
733 hashp->cbucket = bucket;
734 if ((u_int32_t)hashp->cbucket > hashp->MAX_BUCKET) {
735 hashp->cbucket = -1;
736 return (ABNORMAL);
737 }
738 } else {
739 bp = (u_int16_t *)hashp->cpage->page;
740 if (flag == R_NEXT || flag == 0) {
741 hashp->cndx += 2;
742 if (hashp->cndx > bp[0]) {
743 hashp->cpage = NULL;
744 hashp->cbucket++;
745 hashp->cndx = 1;
746 goto next_bucket;
747 }
748 }
749 }
750
751 #ifdef DEBUG
752 assert(bp);
753 assert(bufp);
754 #endif
755 while (bp[hashp->cndx + 1] == OVFLPAGE) {
756 bufp = hashp->cpage =
757 __get_buf(hashp, bp[hashp->cndx], bufp, 0);
758 if (!bufp)
759 return (ERROR);
760 bp = (u_int16_t *)(bufp->page);
761 hashp->cndx = 1;
762 }
763 if (!bp[0]) {
764 hashp->cpage = NULL;
765 ++hashp->cbucket;
766 }
767 }
768 ndx = hashp->cndx;
769 if (bp[ndx + 1] < REAL_KEY) {
770 if (__big_keydata(hashp, bufp, key, data, 1))
771 return (ERROR);
772 } else {
773 if (hashp->cpage == NULL)
774 return (ERROR);
775 key->data = (u_char *)hashp->cpage->page + bp[ndx];
776 key->size = (ndx > 1 ? bp[ndx - 1] : hashp->BSIZE) - bp[ndx];
777 data->data = (u_char *)hashp->cpage->page + bp[ndx + 1];
778 data->size = bp[ndx] - bp[ndx + 1];
779 }
780 return (SUCCESS);
781 }
782
783 /********************************* UTILITIES ************************/
784
785 /*
786 * Returns:
787 * 0 ==> OK
788 * -1 ==> Error
789 */
790 int
__expand_table(HTAB * hashp)791 __expand_table(HTAB *hashp)
792 {
793 u_int32_t old_bucket, new_bucket;
794 int dirsize, new_segnum, spare_ndx;
795
796 #ifdef HASH_STATISTICS
797 hash_expansions++;
798 #endif
799 new_bucket = ++hashp->MAX_BUCKET;
800 old_bucket = (hashp->MAX_BUCKET & hashp->LOW_MASK);
801
802 new_segnum = new_bucket >> hashp->SSHIFT;
803
804 /* Check if we need a new segment */
805 if (new_segnum >= hashp->nsegs) {
806 /* Check if we need to expand directory */
807 if (new_segnum >= hashp->DSIZE) {
808 /* Reallocate directory */
809 dirsize = hashp->DSIZE * sizeof(SEGMENT *);
810 if (!hash_realloc(&hashp->dir, dirsize, dirsize << 1))
811 return (-1);
812 hashp->DSIZE = dirsize << 1;
813 }
814 if ((hashp->dir[new_segnum] =
815 calloc(hashp->SGSIZE, sizeof(SEGMENT))) == NULL)
816 return (-1);
817 hashp->exsegs++;
818 hashp->nsegs++;
819 }
820 /*
821 * If the split point is increasing (MAX_BUCKET's log base 2
822 * * increases), we need to copy the current contents of the spare
823 * split bucket to the next bucket.
824 */
825 spare_ndx = __log2(hashp->MAX_BUCKET + 1);
826 if (spare_ndx > hashp->OVFL_POINT) {
827 hashp->SPARES[spare_ndx] = hashp->SPARES[hashp->OVFL_POINT];
828 hashp->OVFL_POINT = spare_ndx;
829 }
830
831 if (new_bucket > hashp->HIGH_MASK) {
832 /* Starting a new doubling */
833 hashp->LOW_MASK = hashp->HIGH_MASK;
834 hashp->HIGH_MASK = new_bucket | hashp->LOW_MASK;
835 }
836 /* Relocate records to the new bucket */
837 return (__split_page(hashp, old_bucket, new_bucket));
838 }
839
840 /*
841 * If realloc guarantees that the pointer is not destroyed if the realloc
842 * fails, then this routine can go away.
843 */
844 static void *
hash_realloc(SEGMENT ** p_ptr,int oldsize,int newsize)845 hash_realloc(SEGMENT **p_ptr, int oldsize, int newsize)
846 {
847 void *p;
848
849 if ( (p = malloc(newsize)) ) {
850 memmove(p, *p_ptr, oldsize);
851 memset((char *)p + oldsize, 0, newsize - oldsize);
852 free(*p_ptr);
853 *p_ptr = p;
854 }
855 return (p);
856 }
857
858 u_int32_t
__call_hash(HTAB * hashp,char * k,int len)859 __call_hash(HTAB *hashp, char *k, int len)
860 {
861 unsigned int n, bucket;
862
863 n = hashp->hash(k, len);
864 bucket = n & hashp->HIGH_MASK;
865 if (bucket > hashp->MAX_BUCKET)
866 bucket = bucket & hashp->LOW_MASK;
867 return (bucket);
868 }
869
870 /*
871 * Allocate segment table. On error, destroy the table and set errno.
872 *
873 * Returns 0 on success
874 */
875 static int
alloc_segs(HTAB * hashp,int nsegs)876 alloc_segs(HTAB *hashp, int nsegs)
877 {
878 int i;
879 SEGMENT store;
880
881 int save_errno;
882
883 if ((hashp->dir =
884 calloc(hashp->DSIZE, sizeof(SEGMENT *))) == NULL) {
885 save_errno = errno;
886 (void)hdestroy(hashp);
887 errno = save_errno;
888 return (-1);
889 }
890 hashp->nsegs = nsegs;
891 if (nsegs == 0)
892 return (0);
893 /* Allocate segments */
894 if ((store = calloc(nsegs << hashp->SSHIFT, sizeof(SEGMENT))) == NULL) {
895 save_errno = errno;
896 (void)hdestroy(hashp);
897 errno = save_errno;
898 return (-1);
899 }
900 for (i = 0; i < nsegs; i++)
901 hashp->dir[i] = &store[i << hashp->SSHIFT];
902 return (0);
903 }
904
905 #if BYTE_ORDER == LITTLE_ENDIAN
906 /*
907 * Hashp->hdr needs to be byteswapped.
908 */
909 static void
swap_header_copy(HASHHDR * srcp,HASHHDR * destp)910 swap_header_copy(HASHHDR *srcp, HASHHDR *destp)
911 {
912 int i;
913
914 P_32_COPY(srcp->magic, destp->magic);
915 P_32_COPY(srcp->version, destp->version);
916 P_32_COPY(srcp->lorder, destp->lorder);
917 P_32_COPY(srcp->bsize, destp->bsize);
918 P_32_COPY(srcp->bshift, destp->bshift);
919 P_32_COPY(srcp->dsize, destp->dsize);
920 P_32_COPY(srcp->ssize, destp->ssize);
921 P_32_COPY(srcp->sshift, destp->sshift);
922 P_32_COPY(srcp->ovfl_point, destp->ovfl_point);
923 P_32_COPY(srcp->last_freed, destp->last_freed);
924 P_32_COPY(srcp->max_bucket, destp->max_bucket);
925 P_32_COPY(srcp->high_mask, destp->high_mask);
926 P_32_COPY(srcp->low_mask, destp->low_mask);
927 P_32_COPY(srcp->ffactor, destp->ffactor);
928 P_32_COPY(srcp->nkeys, destp->nkeys);
929 P_32_COPY(srcp->hdrpages, destp->hdrpages);
930 P_32_COPY(srcp->h_charkey, destp->h_charkey);
931 for (i = 0; i < NCACHED; i++) {
932 P_32_COPY(srcp->spares[i], destp->spares[i]);
933 P_16_COPY(srcp->bitmaps[i], destp->bitmaps[i]);
934 }
935 }
936
937 static void
swap_header(HTAB * hashp)938 swap_header(HTAB *hashp)
939 {
940 HASHHDR *hdrp;
941 int i;
942
943 hdrp = &hashp->hdr;
944
945 M_32_SWAP(hdrp->magic);
946 M_32_SWAP(hdrp->version);
947 M_32_SWAP(hdrp->lorder);
948 M_32_SWAP(hdrp->bsize);
949 M_32_SWAP(hdrp->bshift);
950 M_32_SWAP(hdrp->dsize);
951 M_32_SWAP(hdrp->ssize);
952 M_32_SWAP(hdrp->sshift);
953 M_32_SWAP(hdrp->ovfl_point);
954 M_32_SWAP(hdrp->last_freed);
955 M_32_SWAP(hdrp->max_bucket);
956 M_32_SWAP(hdrp->high_mask);
957 M_32_SWAP(hdrp->low_mask);
958 M_32_SWAP(hdrp->ffactor);
959 M_32_SWAP(hdrp->nkeys);
960 M_32_SWAP(hdrp->hdrpages);
961 M_32_SWAP(hdrp->h_charkey);
962 for (i = 0; i < NCACHED; i++) {
963 M_32_SWAP(hdrp->spares[i]);
964 M_16_SWAP(hdrp->bitmaps[i]);
965 }
966 }
967 #endif
968