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 55static int alloc_segs(HTAB *, int); 56static int flush_meta(HTAB *); 57static int hash_access(HTAB *, ACTION, DBT *, DBT *); 58static int hash_close(DB *); 59static int hash_delete(const DB *, const DBT *, u_int32_t); 60static int hash_fd(const DB *); 61static int hash_get(const DB *, const DBT *, DBT *, u_int32_t); 62static int hash_put(const DB *, DBT *, const DBT *, u_int32_t); 63static void *hash_realloc(SEGMENT **, int, int); 64static int hash_seq(const DB *, DBT *, DBT *, u_int32_t); 65static int hash_sync(const DB *, u_int32_t); 66static int hdestroy(HTAB *); 67static HTAB *init_hash(HTAB *, const char *, const HASHINFO *); 68static int init_htab(HTAB *, int); 69#if BYTE_ORDER == LITTLE_ENDIAN 70static void swap_header(HTAB *); 71static 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 85int hash_accesses, hash_collisions, hash_expansions, hash_overflows; 86#endif 87 88/************************** INTERFACE ROUTINES ***************************/ 89/* OPEN/CLOSE */ 90 91/* ARGSUSED */ 92DB * 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 224error1: 225 if (hashp != NULL) 226 (void)_close(hashp->fp); 227 228error0: 229 free(hashp); 230 errno = save_errno; 231 return (NULL); 232} 233 234static int 235hash_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 249static int 250hash_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 **********************/ 266static HTAB * 267init_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 */ 332static int 333init_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 */ 375static int 376hdestroy(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 */ 441static int 442hash_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 */ 470static int 471flush_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 */ 516static int 517hash_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 529static int 530hash_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 547static int 548hash_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 */ 568static int 569hash_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 661found: 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 694static int 695hash_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 } 715next_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 */ 786int 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 */ 840static void * 841hash_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 854u_int32_t 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 */ 871static int 872alloc_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 */ 905static void 906swap_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 933static void 934swap_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