hash.c revision 330897
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 * 4. 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) 36static char sccsid[] = "@(#)hash.c 8.9 (Berkeley) 6/16/94"; 37#endif /* LIBC_SCCS and not lint */ 38#include <sys/cdefs.h> 39__FBSDID("$FreeBSD: stable/11/lib/libc/db/hash/hash.c 330897 2018-03-14 03:19:51Z eadler $"); 40 41#include "namespace.h" 42#include <sys/param.h> 43#include <sys/stat.h> 44 45#include <errno.h> 46#include <fcntl.h> 47#include <stdio.h> 48#include <stdlib.h> 49#include <string.h> 50#include <unistd.h> 51#ifdef DEBUG 52#include <assert.h> 53#endif 54#include "un-namespace.h" 55 56#include <db.h> 57#include "hash.h" 58#include "page.h" 59#include "extern.h" 60 61static int alloc_segs(HTAB *, int); 62static int flush_meta(HTAB *); 63static int hash_access(HTAB *, ACTION, DBT *, DBT *); 64static int hash_close(DB *); 65static int hash_delete(const DB *, const DBT *, u_int32_t); 66static int hash_fd(const DB *); 67static int hash_get(const DB *, const DBT *, DBT *, u_int32_t); 68static int hash_put(const DB *, DBT *, const DBT *, u_int32_t); 69static void *hash_realloc(SEGMENT **, int, int); 70static int hash_seq(const DB *, DBT *, DBT *, u_int32_t); 71static int hash_sync(const DB *, u_int32_t); 72static int hdestroy(HTAB *); 73static HTAB *init_hash(HTAB *, const char *, const HASHINFO *); 74static int init_htab(HTAB *, int); 75#if BYTE_ORDER == LITTLE_ENDIAN 76static void swap_header(HTAB *); 77static void swap_header_copy(HASHHDR *, HASHHDR *); 78#endif 79 80/* Fast arithmetic, relying on powers of 2, */ 81#define MOD(x, y) ((x) & ((y) - 1)) 82 83#define RETURN_ERROR(ERR, LOC) { save_errno = ERR; goto LOC; } 84 85/* Return values */ 86#define SUCCESS (0) 87#define ERROR (-1) 88#define ABNORMAL (1) 89 90#ifdef HASH_STATISTICS 91int hash_accesses, hash_collisions, hash_expansions, hash_overflows; 92#endif 93 94/************************** INTERFACE ROUTINES ***************************/ 95/* OPEN/CLOSE */ 96 97/* ARGSUSED */ 98DB * 99__hash_open(const char *file, int flags, int mode, 100 const HASHINFO *info, /* Special directives for create */ 101 int dflags) 102{ 103 HTAB *hashp; 104 struct stat statbuf; 105 DB *dbp; 106 int bpages, hdrsize, new_table, nsegs, save_errno; 107 108 if ((flags & O_ACCMODE) == O_WRONLY) { 109 errno = EINVAL; 110 return (NULL); 111 } 112 113 if (!(hashp = (HTAB *)calloc(1, sizeof(HTAB)))) 114 return (NULL); 115 hashp->fp = -1; 116 117 /* 118 * Even if user wants write only, we need to be able to read 119 * the actual file, so we need to open it read/write. But, the 120 * field in the hashp structure needs to be accurate so that 121 * we can check accesses. 122 */ 123 hashp->flags = flags; 124 125 if (file) { 126 if ((hashp->fp = _open(file, flags | O_CLOEXEC, mode)) == -1) 127 RETURN_ERROR(errno, error0); 128 new_table = _fstat(hashp->fp, &statbuf) == 0 && 129 statbuf.st_size == 0 && (flags & O_ACCMODE) != O_RDONLY; 130 } else 131 new_table = 1; 132 133 if (new_table) { 134 if (!(hashp = init_hash(hashp, file, info))) 135 RETURN_ERROR(errno, error1); 136 } else { 137 /* Table already exists */ 138 if (info && info->hash) 139 hashp->hash = info->hash; 140 else 141 hashp->hash = __default_hash; 142 143 hdrsize = _read(hashp->fp, &hashp->hdr, sizeof(HASHHDR)); 144#if BYTE_ORDER == LITTLE_ENDIAN 145 swap_header(hashp); 146#endif 147 if (hdrsize == -1) 148 RETURN_ERROR(errno, error1); 149 if (hdrsize != sizeof(HASHHDR)) 150 RETURN_ERROR(EFTYPE, error1); 151 /* Verify file type, versions and hash function */ 152 if (hashp->MAGIC != HASHMAGIC) 153 RETURN_ERROR(EFTYPE, error1); 154#define OLDHASHVERSION 1 155 if (hashp->VERSION != HASHVERSION && 156 hashp->VERSION != OLDHASHVERSION) 157 RETURN_ERROR(EFTYPE, error1); 158 if ((int32_t)hashp->hash(CHARKEY, sizeof(CHARKEY)) != hashp->H_CHARKEY) 159 RETURN_ERROR(EFTYPE, error1); 160 /* 161 * Figure out how many segments we need. Max_Bucket is the 162 * maximum bucket number, so the number of buckets is 163 * max_bucket + 1. 164 */ 165 nsegs = howmany(hashp->MAX_BUCKET + 1, hashp->SGSIZE); 166 if (alloc_segs(hashp, nsegs)) 167 /* 168 * If alloc_segs fails, table will have been destroyed 169 * and errno will have been set. 170 */ 171 return (NULL); 172 /* Read in bitmaps */ 173 bpages = (hashp->SPARES[hashp->OVFL_POINT] + 174 (hashp->BSIZE << BYTE_SHIFT) - 1) >> 175 (hashp->BSHIFT + BYTE_SHIFT); 176 177 hashp->nmaps = bpages; 178 (void)memset(&hashp->mapp[0], 0, bpages * sizeof(u_int32_t *)); 179 } 180 181 /* Initialize Buffer Manager */ 182 if (info && info->cachesize) 183 __buf_init(hashp, info->cachesize); 184 else 185 __buf_init(hashp, DEF_BUFSIZE); 186 187 hashp->new_file = new_table; 188 hashp->save_file = file && (hashp->flags & O_RDWR); 189 hashp->cbucket = -1; 190 if (!(dbp = (DB *)malloc(sizeof(DB)))) { 191 save_errno = errno; 192 hdestroy(hashp); 193 errno = save_errno; 194 return (NULL); 195 } 196 dbp->internal = hashp; 197 dbp->close = hash_close; 198 dbp->del = hash_delete; 199 dbp->fd = hash_fd; 200 dbp->get = hash_get; 201 dbp->put = hash_put; 202 dbp->seq = hash_seq; 203 dbp->sync = hash_sync; 204 dbp->type = DB_HASH; 205 206#ifdef DEBUG 207 (void)fprintf(stderr, 208"%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", 209 "init_htab:", 210 "TABLE POINTER ", hashp, 211 "BUCKET SIZE ", hashp->BSIZE, 212 "BUCKET SHIFT ", hashp->BSHIFT, 213 "DIRECTORY SIZE ", hashp->DSIZE, 214 "SEGMENT SIZE ", hashp->SGSIZE, 215 "SEGMENT SHIFT ", hashp->SSHIFT, 216 "FILL FACTOR ", hashp->FFACTOR, 217 "MAX BUCKET ", hashp->MAX_BUCKET, 218 "OVFL POINT ", hashp->OVFL_POINT, 219 "LAST FREED ", hashp->LAST_FREED, 220 "HIGH MASK ", hashp->HIGH_MASK, 221 "LOW MASK ", hashp->LOW_MASK, 222 "NSEGS ", hashp->nsegs, 223 "NKEYS ", hashp->NKEYS); 224#endif 225#ifdef HASH_STATISTICS 226 hash_overflows = hash_accesses = hash_collisions = hash_expansions = 0; 227#endif 228 return (dbp); 229 230error1: 231 if (hashp != NULL) 232 (void)_close(hashp->fp); 233 234error0: 235 free(hashp); 236 errno = save_errno; 237 return (NULL); 238} 239 240static int 241hash_close(DB *dbp) 242{ 243 HTAB *hashp; 244 int retval; 245 246 if (!dbp) 247 return (ERROR); 248 249 hashp = (HTAB *)dbp->internal; 250 retval = hdestroy(hashp); 251 free(dbp); 252 return (retval); 253} 254 255static int 256hash_fd(const DB *dbp) 257{ 258 HTAB *hashp; 259 260 if (!dbp) 261 return (ERROR); 262 263 hashp = (HTAB *)dbp->internal; 264 if (hashp->fp == -1) { 265 errno = ENOENT; 266 return (-1); 267 } 268 return (hashp->fp); 269} 270 271/************************** LOCAL CREATION ROUTINES **********************/ 272static HTAB * 273init_hash(HTAB *hashp, const char *file, const HASHINFO *info) 274{ 275 struct stat statbuf; 276 int nelem; 277 278 nelem = 1; 279 hashp->NKEYS = 0; 280 hashp->LORDER = BYTE_ORDER; 281 hashp->BSIZE = DEF_BUCKET_SIZE; 282 hashp->BSHIFT = DEF_BUCKET_SHIFT; 283 hashp->SGSIZE = DEF_SEGSIZE; 284 hashp->SSHIFT = DEF_SEGSIZE_SHIFT; 285 hashp->DSIZE = DEF_DIRSIZE; 286 hashp->FFACTOR = DEF_FFACTOR; 287 hashp->hash = __default_hash; 288 memset(hashp->SPARES, 0, sizeof(hashp->SPARES)); 289 memset(hashp->BITMAPS, 0, sizeof (hashp->BITMAPS)); 290 291 /* Fix bucket size to be optimal for file system */ 292 if (file != NULL) { 293 if (stat(file, &statbuf)) 294 return (NULL); 295 hashp->BSIZE = statbuf.st_blksize; 296 if (hashp->BSIZE > MAX_BSIZE) 297 hashp->BSIZE = MAX_BSIZE; 298 hashp->BSHIFT = __log2(hashp->BSIZE); 299 } 300 301 if (info) { 302 if (info->bsize) { 303 /* Round pagesize up to power of 2 */ 304 hashp->BSHIFT = __log2(info->bsize); 305 hashp->BSIZE = 1 << hashp->BSHIFT; 306 if (hashp->BSIZE > MAX_BSIZE) { 307 errno = EINVAL; 308 return (NULL); 309 } 310 } 311 if (info->ffactor) 312 hashp->FFACTOR = info->ffactor; 313 if (info->hash) 314 hashp->hash = info->hash; 315 if (info->nelem) 316 nelem = info->nelem; 317 if (info->lorder) { 318 if (info->lorder != BIG_ENDIAN && 319 info->lorder != LITTLE_ENDIAN) { 320 errno = EINVAL; 321 return (NULL); 322 } 323 hashp->LORDER = info->lorder; 324 } 325 } 326 /* init_htab should destroy the table and set errno if it fails */ 327 if (init_htab(hashp, nelem)) 328 return (NULL); 329 else 330 return (hashp); 331} 332/* 333 * This calls alloc_segs which may run out of memory. Alloc_segs will destroy 334 * the table and set errno, so we just pass the error information along. 335 * 336 * Returns 0 on No Error 337 */ 338static int 339init_htab(HTAB *hashp, int nelem) 340{ 341 int nbuckets, nsegs, l2; 342 343 /* 344 * Divide number of elements by the fill factor and determine a 345 * desired number of buckets. Allocate space for the next greater 346 * power of two number of buckets. 347 */ 348 nelem = (nelem - 1) / hashp->FFACTOR + 1; 349 350 l2 = __log2(MAX(nelem, 2)); 351 nbuckets = 1 << l2; 352 353 hashp->SPARES[l2] = l2 + 1; 354 hashp->SPARES[l2 + 1] = l2 + 1; 355 hashp->OVFL_POINT = l2; 356 hashp->LAST_FREED = 2; 357 358 /* First bitmap page is at: splitpoint l2 page offset 1 */ 359 if (__ibitmap(hashp, OADDR_OF(l2, 1), l2 + 1, 0)) 360 return (-1); 361 362 hashp->MAX_BUCKET = hashp->LOW_MASK = nbuckets - 1; 363 hashp->HIGH_MASK = (nbuckets << 1) - 1; 364 hashp->HDRPAGES = ((MAX(sizeof(HASHHDR), MINHDRSIZE) - 1) >> 365 hashp->BSHIFT) + 1; 366 367 nsegs = (nbuckets - 1) / hashp->SGSIZE + 1; 368 nsegs = 1 << __log2(nsegs); 369 370 if (nsegs > hashp->DSIZE) 371 hashp->DSIZE = nsegs; 372 return (alloc_segs(hashp, nsegs)); 373} 374 375/********************** DESTROY/CLOSE ROUTINES ************************/ 376 377/* 378 * Flushes any changes to the file if necessary and destroys the hashp 379 * structure, freeing all allocated space. 380 */ 381static int 382hdestroy(HTAB *hashp) 383{ 384 int i, save_errno; 385 386 save_errno = 0; 387 388#ifdef HASH_STATISTICS 389 (void)fprintf(stderr, "hdestroy: accesses %ld collisions %ld\n", 390 hash_accesses, hash_collisions); 391 (void)fprintf(stderr, "hdestroy: expansions %ld\n", 392 hash_expansions); 393 (void)fprintf(stderr, "hdestroy: overflows %ld\n", 394 hash_overflows); 395 (void)fprintf(stderr, "keys %ld maxp %d segmentcount %d\n", 396 hashp->NKEYS, hashp->MAX_BUCKET, hashp->nsegs); 397 398 for (i = 0; i < NCACHED; i++) 399 (void)fprintf(stderr, 400 "spares[%d] = %d\n", i, hashp->SPARES[i]); 401#endif 402 /* 403 * Call on buffer manager to free buffers, and if required, 404 * write them to disk. 405 */ 406 if (__buf_free(hashp, 1, hashp->save_file)) 407 save_errno = errno; 408 if (hashp->dir) { 409 free(*hashp->dir); /* Free initial segments */ 410 /* Free extra segments */ 411 while (hashp->exsegs--) 412 free(hashp->dir[--hashp->nsegs]); 413 free(hashp->dir); 414 } 415 if (flush_meta(hashp) && !save_errno) 416 save_errno = errno; 417 /* Free Bigmaps */ 418 for (i = 0; i < hashp->nmaps; i++) 419 if (hashp->mapp[i]) 420 free(hashp->mapp[i]); 421 if (hashp->tmp_key) 422 free(hashp->tmp_key); 423 if (hashp->tmp_buf) 424 free(hashp->tmp_buf); 425 426 if (hashp->fp != -1) { 427 if (hashp->save_file) 428 (void)_fsync(hashp->fp); 429 (void)_close(hashp->fp); 430 } 431 432 free(hashp); 433 434 if (save_errno) { 435 errno = save_errno; 436 return (ERROR); 437 } 438 return (SUCCESS); 439} 440/* 441 * Write modified pages to disk 442 * 443 * Returns: 444 * 0 == OK 445 * -1 ERROR 446 */ 447static int 448hash_sync(const DB *dbp, u_int32_t flags) 449{ 450 HTAB *hashp; 451 452 if (flags != 0) { 453 errno = EINVAL; 454 return (ERROR); 455 } 456 457 if (!dbp) 458 return (ERROR); 459 460 hashp = (HTAB *)dbp->internal; 461 if (!hashp->save_file) 462 return (0); 463 if (__buf_free(hashp, 0, 1) || flush_meta(hashp)) 464 return (ERROR); 465 if (hashp->fp != -1 && _fsync(hashp->fp) != 0) 466 return (ERROR); 467 hashp->new_file = 0; 468 return (0); 469} 470 471/* 472 * Returns: 473 * 0 == OK 474 * -1 indicates that errno should be set 475 */ 476static int 477flush_meta(HTAB *hashp) 478{ 479 HASHHDR *whdrp; 480#if BYTE_ORDER == LITTLE_ENDIAN 481 HASHHDR whdr; 482#endif 483 int fp, i, wsize; 484 485 if (!hashp->save_file) 486 return (0); 487 hashp->MAGIC = HASHMAGIC; 488 hashp->VERSION = HASHVERSION; 489 hashp->H_CHARKEY = hashp->hash(CHARKEY, sizeof(CHARKEY)); 490 491 fp = hashp->fp; 492 whdrp = &hashp->hdr; 493#if BYTE_ORDER == LITTLE_ENDIAN 494 whdrp = &whdr; 495 swap_header_copy(&hashp->hdr, whdrp); 496#endif 497 if ((wsize = pwrite(fp, whdrp, sizeof(HASHHDR), (off_t)0)) == -1) 498 return (-1); 499 else 500 if (wsize != sizeof(HASHHDR)) { 501 errno = EFTYPE; 502 hashp->error = errno; 503 return (-1); 504 } 505 for (i = 0; i < NCACHED; i++) 506 if (hashp->mapp[i]) 507 if (__put_page(hashp, (char *)hashp->mapp[i], 508 hashp->BITMAPS[i], 0, 1)) 509 return (-1); 510 return (0); 511} 512 513/*******************************SEARCH ROUTINES *****************************/ 514/* 515 * All the access routines return 516 * 517 * Returns: 518 * 0 on SUCCESS 519 * 1 to indicate an external ERROR (i.e. key not found, etc) 520 * -1 to indicate an internal ERROR (i.e. out of memory, etc) 521 */ 522static int 523hash_get(const DB *dbp, const DBT *key, DBT *data, u_int32_t flag) 524{ 525 HTAB *hashp; 526 527 hashp = (HTAB *)dbp->internal; 528 if (flag) { 529 hashp->error = errno = EINVAL; 530 return (ERROR); 531 } 532 return (hash_access(hashp, HASH_GET, (DBT *)key, data)); 533} 534 535static int 536hash_put(const DB *dbp, DBT *key, const DBT *data, u_int32_t flag) 537{ 538 HTAB *hashp; 539 540 hashp = (HTAB *)dbp->internal; 541 if (flag && flag != R_NOOVERWRITE) { 542 hashp->error = errno = EINVAL; 543 return (ERROR); 544 } 545 if ((hashp->flags & O_ACCMODE) == O_RDONLY) { 546 hashp->error = errno = EPERM; 547 return (ERROR); 548 } 549 return (hash_access(hashp, flag == R_NOOVERWRITE ? 550 HASH_PUTNEW : HASH_PUT, (DBT *)key, (DBT *)data)); 551} 552 553static int 554hash_delete(const DB *dbp, const DBT *key, 555 u_int32_t flag) /* Ignored */ 556{ 557 HTAB *hashp; 558 559 hashp = (HTAB *)dbp->internal; 560 if (flag && flag != R_CURSOR) { 561 hashp->error = errno = EINVAL; 562 return (ERROR); 563 } 564 if ((hashp->flags & O_ACCMODE) == O_RDONLY) { 565 hashp->error = errno = EPERM; 566 return (ERROR); 567 } 568 return (hash_access(hashp, HASH_DELETE, (DBT *)key, NULL)); 569} 570 571/* 572 * Assume that hashp has been set in wrapper routine. 573 */ 574static int 575hash_access(HTAB *hashp, ACTION action, DBT *key, DBT *val) 576{ 577 BUFHEAD *rbufp; 578 BUFHEAD *bufp, *save_bufp; 579 u_int16_t *bp; 580 int n, ndx, off, size; 581 char *kp; 582 u_int16_t pageno; 583 584#ifdef HASH_STATISTICS 585 hash_accesses++; 586#endif 587 588 off = hashp->BSIZE; 589 size = key->size; 590 kp = (char *)key->data; 591 rbufp = __get_buf(hashp, __call_hash(hashp, kp, size), NULL, 0); 592 if (!rbufp) 593 return (ERROR); 594 save_bufp = rbufp; 595 596 /* Pin the bucket chain */ 597 rbufp->flags |= BUF_PIN; 598 for (bp = (u_int16_t *)rbufp->page, n = *bp++, ndx = 1; ndx < n;) 599 if (bp[1] >= REAL_KEY) { 600 /* Real key/data pair */ 601 if (size == off - *bp && 602 memcmp(kp, rbufp->page + *bp, size) == 0) 603 goto found; 604 off = bp[1]; 605#ifdef HASH_STATISTICS 606 hash_collisions++; 607#endif 608 bp += 2; 609 ndx += 2; 610 } else if (bp[1] == OVFLPAGE) { 611 rbufp = __get_buf(hashp, *bp, rbufp, 0); 612 if (!rbufp) { 613 save_bufp->flags &= ~BUF_PIN; 614 return (ERROR); 615 } 616 /* FOR LOOP INIT */ 617 bp = (u_int16_t *)rbufp->page; 618 n = *bp++; 619 ndx = 1; 620 off = hashp->BSIZE; 621 } else if (bp[1] < REAL_KEY) { 622 if ((ndx = 623 __find_bigpair(hashp, rbufp, ndx, kp, size)) > 0) 624 goto found; 625 if (ndx == -2) { 626 bufp = rbufp; 627 if (!(pageno = 628 __find_last_page(hashp, &bufp))) { 629 ndx = 0; 630 rbufp = bufp; 631 break; /* FOR */ 632 } 633 rbufp = __get_buf(hashp, pageno, bufp, 0); 634 if (!rbufp) { 635 save_bufp->flags &= ~BUF_PIN; 636 return (ERROR); 637 } 638 /* FOR LOOP INIT */ 639 bp = (u_int16_t *)rbufp->page; 640 n = *bp++; 641 ndx = 1; 642 off = hashp->BSIZE; 643 } else { 644 save_bufp->flags &= ~BUF_PIN; 645 return (ERROR); 646 } 647 } 648 649 /* Not found */ 650 switch (action) { 651 case HASH_PUT: 652 case HASH_PUTNEW: 653 if (__addel(hashp, rbufp, key, val)) { 654 save_bufp->flags &= ~BUF_PIN; 655 return (ERROR); 656 } else { 657 save_bufp->flags &= ~BUF_PIN; 658 return (SUCCESS); 659 } 660 case HASH_GET: 661 case HASH_DELETE: 662 default: 663 save_bufp->flags &= ~BUF_PIN; 664 return (ABNORMAL); 665 } 666 667found: 668 switch (action) { 669 case HASH_PUTNEW: 670 save_bufp->flags &= ~BUF_PIN; 671 return (ABNORMAL); 672 case HASH_GET: 673 bp = (u_int16_t *)rbufp->page; 674 if (bp[ndx + 1] < REAL_KEY) { 675 if (__big_return(hashp, rbufp, ndx, val, 0)) 676 return (ERROR); 677 } else { 678 val->data = (u_char *)rbufp->page + (int)bp[ndx + 1]; 679 val->size = bp[ndx] - bp[ndx + 1]; 680 } 681 break; 682 case HASH_PUT: 683 if ((__delpair(hashp, rbufp, ndx)) || 684 (__addel(hashp, rbufp, key, val))) { 685 save_bufp->flags &= ~BUF_PIN; 686 return (ERROR); 687 } 688 break; 689 case HASH_DELETE: 690 if (__delpair(hashp, rbufp, ndx)) 691 return (ERROR); 692 break; 693 default: 694 abort(); 695 } 696 save_bufp->flags &= ~BUF_PIN; 697 return (SUCCESS); 698} 699 700static int 701hash_seq(const DB *dbp, DBT *key, DBT *data, u_int32_t flag) 702{ 703 u_int32_t bucket; 704 BUFHEAD *bufp; 705 HTAB *hashp; 706 u_int16_t *bp, ndx; 707 708 hashp = (HTAB *)dbp->internal; 709 if (flag && flag != R_FIRST && flag != R_NEXT) { 710 hashp->error = errno = EINVAL; 711 return (ERROR); 712 } 713#ifdef HASH_STATISTICS 714 hash_accesses++; 715#endif 716 if ((hashp->cbucket < 0) || (flag == R_FIRST)) { 717 hashp->cbucket = 0; 718 hashp->cndx = 1; 719 hashp->cpage = NULL; 720 } 721next_bucket: 722 for (bp = NULL; !bp || !bp[0]; ) { 723 if (!(bufp = hashp->cpage)) { 724 for (bucket = hashp->cbucket; 725 bucket <= hashp->MAX_BUCKET; 726 bucket++, hashp->cndx = 1) { 727 bufp = __get_buf(hashp, bucket, NULL, 0); 728 if (!bufp) 729 return (ERROR); 730 hashp->cpage = bufp; 731 bp = (u_int16_t *)bufp->page; 732 if (bp[0]) 733 break; 734 } 735 hashp->cbucket = bucket; 736 if ((u_int32_t)hashp->cbucket > hashp->MAX_BUCKET) { 737 hashp->cbucket = -1; 738 return (ABNORMAL); 739 } 740 } else { 741 bp = (u_int16_t *)hashp->cpage->page; 742 if (flag == R_NEXT || flag == 0) { 743 hashp->cndx += 2; 744 if (hashp->cndx > bp[0]) { 745 hashp->cpage = NULL; 746 hashp->cbucket++; 747 hashp->cndx = 1; 748 goto next_bucket; 749 } 750 } 751 } 752 753#ifdef DEBUG 754 assert(bp); 755 assert(bufp); 756#endif 757 while (bp[hashp->cndx + 1] == OVFLPAGE) { 758 bufp = hashp->cpage = 759 __get_buf(hashp, bp[hashp->cndx], bufp, 0); 760 if (!bufp) 761 return (ERROR); 762 bp = (u_int16_t *)(bufp->page); 763 hashp->cndx = 1; 764 } 765 if (!bp[0]) { 766 hashp->cpage = NULL; 767 ++hashp->cbucket; 768 } 769 } 770 ndx = hashp->cndx; 771 if (bp[ndx + 1] < REAL_KEY) { 772 if (__big_keydata(hashp, bufp, key, data, 1)) 773 return (ERROR); 774 } else { 775 if (hashp->cpage == NULL) 776 return (ERROR); 777 key->data = (u_char *)hashp->cpage->page + bp[ndx]; 778 key->size = (ndx > 1 ? bp[ndx - 1] : hashp->BSIZE) - bp[ndx]; 779 data->data = (u_char *)hashp->cpage->page + bp[ndx + 1]; 780 data->size = bp[ndx] - bp[ndx + 1]; 781 } 782 return (SUCCESS); 783} 784 785/********************************* UTILITIES ************************/ 786 787/* 788 * Returns: 789 * 0 ==> OK 790 * -1 ==> Error 791 */ 792int 793__expand_table(HTAB *hashp) 794{ 795 u_int32_t old_bucket, new_bucket; 796 int dirsize, new_segnum, spare_ndx; 797 798#ifdef HASH_STATISTICS 799 hash_expansions++; 800#endif 801 new_bucket = ++hashp->MAX_BUCKET; 802 old_bucket = (hashp->MAX_BUCKET & hashp->LOW_MASK); 803 804 new_segnum = new_bucket >> hashp->SSHIFT; 805 806 /* Check if we need a new segment */ 807 if (new_segnum >= hashp->nsegs) { 808 /* Check if we need to expand directory */ 809 if (new_segnum >= hashp->DSIZE) { 810 /* Reallocate directory */ 811 dirsize = hashp->DSIZE * sizeof(SEGMENT *); 812 if (!hash_realloc(&hashp->dir, dirsize, dirsize << 1)) 813 return (-1); 814 hashp->DSIZE = dirsize << 1; 815 } 816 if ((hashp->dir[new_segnum] = 817 calloc(hashp->SGSIZE, sizeof(SEGMENT))) == NULL) 818 return (-1); 819 hashp->exsegs++; 820 hashp->nsegs++; 821 } 822 /* 823 * If the split point is increasing (MAX_BUCKET's log base 2 824 * * increases), we need to copy the current contents of the spare 825 * split bucket to the next bucket. 826 */ 827 spare_ndx = __log2(hashp->MAX_BUCKET + 1); 828 if (spare_ndx > hashp->OVFL_POINT) { 829 hashp->SPARES[spare_ndx] = hashp->SPARES[hashp->OVFL_POINT]; 830 hashp->OVFL_POINT = spare_ndx; 831 } 832 833 if (new_bucket > hashp->HIGH_MASK) { 834 /* Starting a new doubling */ 835 hashp->LOW_MASK = hashp->HIGH_MASK; 836 hashp->HIGH_MASK = new_bucket | hashp->LOW_MASK; 837 } 838 /* Relocate records to the new bucket */ 839 return (__split_page(hashp, old_bucket, new_bucket)); 840} 841 842/* 843 * If realloc guarantees that the pointer is not destroyed if the realloc 844 * fails, then this routine can go away. 845 */ 846static void * 847hash_realloc(SEGMENT **p_ptr, int oldsize, int newsize) 848{ 849 void *p; 850 851 if ( (p = malloc(newsize)) ) { 852 memmove(p, *p_ptr, oldsize); 853 memset((char *)p + oldsize, 0, newsize - oldsize); 854 free(*p_ptr); 855 *p_ptr = p; 856 } 857 return (p); 858} 859 860u_int32_t 861__call_hash(HTAB *hashp, char *k, int len) 862{ 863 unsigned int n, bucket; 864 865 n = hashp->hash(k, len); 866 bucket = n & hashp->HIGH_MASK; 867 if (bucket > hashp->MAX_BUCKET) 868 bucket = bucket & hashp->LOW_MASK; 869 return (bucket); 870} 871 872/* 873 * Allocate segment table. On error, destroy the table and set errno. 874 * 875 * Returns 0 on success 876 */ 877static int 878alloc_segs(HTAB *hashp, int nsegs) 879{ 880 int i; 881 SEGMENT store; 882 883 int save_errno; 884 885 if ((hashp->dir = 886 calloc(hashp->DSIZE, sizeof(SEGMENT *))) == NULL) { 887 save_errno = errno; 888 (void)hdestroy(hashp); 889 errno = save_errno; 890 return (-1); 891 } 892 hashp->nsegs = nsegs; 893 if (nsegs == 0) 894 return (0); 895 /* Allocate segments */ 896 if ((store = calloc(nsegs << hashp->SSHIFT, sizeof(SEGMENT))) == NULL) { 897 save_errno = errno; 898 (void)hdestroy(hashp); 899 errno = save_errno; 900 return (-1); 901 } 902 for (i = 0; i < nsegs; i++) 903 hashp->dir[i] = &store[i << hashp->SSHIFT]; 904 return (0); 905} 906 907#if BYTE_ORDER == LITTLE_ENDIAN 908/* 909 * Hashp->hdr needs to be byteswapped. 910 */ 911static void 912swap_header_copy(HASHHDR *srcp, HASHHDR *destp) 913{ 914 int i; 915 916 P_32_COPY(srcp->magic, destp->magic); 917 P_32_COPY(srcp->version, destp->version); 918 P_32_COPY(srcp->lorder, destp->lorder); 919 P_32_COPY(srcp->bsize, destp->bsize); 920 P_32_COPY(srcp->bshift, destp->bshift); 921 P_32_COPY(srcp->dsize, destp->dsize); 922 P_32_COPY(srcp->ssize, destp->ssize); 923 P_32_COPY(srcp->sshift, destp->sshift); 924 P_32_COPY(srcp->ovfl_point, destp->ovfl_point); 925 P_32_COPY(srcp->last_freed, destp->last_freed); 926 P_32_COPY(srcp->max_bucket, destp->max_bucket); 927 P_32_COPY(srcp->high_mask, destp->high_mask); 928 P_32_COPY(srcp->low_mask, destp->low_mask); 929 P_32_COPY(srcp->ffactor, destp->ffactor); 930 P_32_COPY(srcp->nkeys, destp->nkeys); 931 P_32_COPY(srcp->hdrpages, destp->hdrpages); 932 P_32_COPY(srcp->h_charkey, destp->h_charkey); 933 for (i = 0; i < NCACHED; i++) { 934 P_32_COPY(srcp->spares[i], destp->spares[i]); 935 P_16_COPY(srcp->bitmaps[i], destp->bitmaps[i]); 936 } 937} 938 939static void 940swap_header(HTAB *hashp) 941{ 942 HASHHDR *hdrp; 943 int i; 944 945 hdrp = &hashp->hdr; 946 947 M_32_SWAP(hdrp->magic); 948 M_32_SWAP(hdrp->version); 949 M_32_SWAP(hdrp->lorder); 950 M_32_SWAP(hdrp->bsize); 951 M_32_SWAP(hdrp->bshift); 952 M_32_SWAP(hdrp->dsize); 953 M_32_SWAP(hdrp->ssize); 954 M_32_SWAP(hdrp->sshift); 955 M_32_SWAP(hdrp->ovfl_point); 956 M_32_SWAP(hdrp->last_freed); 957 M_32_SWAP(hdrp->max_bucket); 958 M_32_SWAP(hdrp->high_mask); 959 M_32_SWAP(hdrp->low_mask); 960 M_32_SWAP(hdrp->ffactor); 961 M_32_SWAP(hdrp->nkeys); 962 M_32_SWAP(hdrp->hdrpages); 963 M_32_SWAP(hdrp->h_charkey); 964 for (i = 0; i < NCACHED; i++) { 965 M_32_SWAP(hdrp->spares[i]); 966 M_16_SWAP(hdrp->bitmaps[i]); 967 } 968} 969#endif 970