1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1990, 1993, 1994 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Margo Seltzer. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 #if defined(LIBC_SCCS) && !defined(lint) 36 static char sccsid[] = "@(#)hash.c 8.9 (Berkeley) 6/16/94"; 37 #endif /* LIBC_SCCS and not lint */ 38 #include "namespace.h" 39 #include <sys/param.h> 40 #include <sys/stat.h> 41 42 #include <errno.h> 43 #include <fcntl.h> 44 #include <stdio.h> 45 #include <stdlib.h> 46 #include <string.h> 47 #include <unistd.h> 48 #ifdef DEBUG 49 #include <assert.h> 50 #endif 51 #include "un-namespace.h" 52 53 #include <db.h> 54 #include "hash.h" 55 #include "page.h" 56 #include "extern.h" 57 58 static int alloc_segs(HTAB *, int); 59 static int flush_meta(HTAB *); 60 static int hash_access(HTAB *, ACTION, DBT *, DBT *); 61 static int hash_close(DB *); 62 static int hash_delete(const DB *, const DBT *, u_int32_t); 63 static int hash_fd(const DB *); 64 static int hash_get(const DB *, const DBT *, DBT *, u_int32_t); 65 static int hash_put(const DB *, DBT *, const DBT *, u_int32_t); 66 static void *hash_realloc(SEGMENT **, int, int); 67 static int hash_seq(const DB *, DBT *, DBT *, u_int32_t); 68 static int hash_sync(const DB *, u_int32_t); 69 static int hdestroy(HTAB *); 70 static HTAB *init_hash(HTAB *, const char *, const HASHINFO *); 71 static int init_htab(HTAB *, int); 72 #if BYTE_ORDER == LITTLE_ENDIAN 73 static void swap_header(HTAB *); 74 static void swap_header_copy(HASHHDR *, HASHHDR *); 75 #endif 76 77 /* Fast arithmetic, relying on powers of 2, */ 78 #define MOD(x, y) ((x) & ((y) - 1)) 79 80 #define RETURN_ERROR(ERR, LOC) { save_errno = ERR; goto LOC; } 81 82 /* Return values */ 83 #define SUCCESS (0) 84 #define ERROR (-1) 85 #define ABNORMAL (1) 86 87 #ifdef HASH_STATISTICS 88 int hash_accesses, hash_collisions, hash_expansions, hash_overflows; 89 #endif 90 91 /************************** INTERFACE ROUTINES ***************************/ 92 /* OPEN/CLOSE */ 93 94 /* ARGSUSED */ 95 DB * 96 __hash_open(const char *file, int flags, int mode, 97 const HASHINFO *info, /* Special directives for create */ 98 int dflags) 99 { 100 HTAB *hashp; 101 struct stat statbuf; 102 DB *dbp; 103 int bpages, hdrsize, new_table, nsegs, save_errno; 104 105 if ((flags & O_ACCMODE) == O_WRONLY) { 106 errno = EINVAL; 107 return (NULL); 108 } 109 110 if (!(hashp = (HTAB *)calloc(1, sizeof(HTAB)))) 111 return (NULL); 112 hashp->fp = -1; 113 114 /* 115 * Even if user wants write only, we need to be able to read 116 * the actual file, so we need to open it read/write. But, the 117 * field in the hashp structure needs to be accurate so that 118 * we can check accesses. 119 */ 120 hashp->flags = flags; 121 122 if (file) { 123 if ((hashp->fp = _open(file, flags | O_CLOEXEC, mode)) == -1) 124 RETURN_ERROR(errno, error0); 125 new_table = _fstat(hashp->fp, &statbuf) == 0 && 126 statbuf.st_size == 0 && (flags & O_ACCMODE) != O_RDONLY; 127 } else 128 new_table = 1; 129 130 if (new_table) { 131 if (!(hashp = init_hash(hashp, file, info))) 132 RETURN_ERROR(errno, error1); 133 } else { 134 /* Table already exists */ 135 if (info && info->hash) 136 hashp->hash = info->hash; 137 else 138 hashp->hash = __default_hash; 139 140 hdrsize = _read(hashp->fp, &hashp->hdr, sizeof(HASHHDR)); 141 #if BYTE_ORDER == LITTLE_ENDIAN 142 swap_header(hashp); 143 #endif 144 if (hdrsize == -1) 145 RETURN_ERROR(errno, error1); 146 if (hdrsize != sizeof(HASHHDR)) 147 RETURN_ERROR(EFTYPE, error1); 148 /* Verify file type, versions and hash function */ 149 if (hashp->MAGIC != HASHMAGIC) 150 RETURN_ERROR(EFTYPE, error1); 151 #define OLDHASHVERSION 1 152 if (hashp->VERSION != HASHVERSION && 153 hashp->VERSION != OLDHASHVERSION) 154 RETURN_ERROR(EFTYPE, error1); 155 if ((int32_t)hashp->hash(CHARKEY, sizeof(CHARKEY)) != hashp->H_CHARKEY) 156 RETURN_ERROR(EFTYPE, error1); 157 /* 158 * Figure out how many segments we need. Max_Bucket is the 159 * maximum bucket number, so the number of buckets is 160 * max_bucket + 1. 161 */ 162 nsegs = howmany(hashp->MAX_BUCKET + 1, hashp->SGSIZE); 163 if (alloc_segs(hashp, nsegs)) 164 /* 165 * If alloc_segs fails, table will have been destroyed 166 * and errno will have been set. 167 */ 168 return (NULL); 169 /* Read in bitmaps */ 170 bpages = (hashp->SPARES[hashp->OVFL_POINT] + 171 (hashp->BSIZE << BYTE_SHIFT) - 1) >> 172 (hashp->BSHIFT + BYTE_SHIFT); 173 174 hashp->nmaps = bpages; 175 (void)memset(&hashp->mapp[0], 0, bpages * sizeof(u_int32_t *)); 176 } 177 178 /* Initialize Buffer Manager */ 179 if (info && info->cachesize) 180 __buf_init(hashp, info->cachesize); 181 else 182 __buf_init(hashp, DEF_BUFSIZE); 183 184 hashp->new_file = new_table; 185 hashp->save_file = file && (hashp->flags & O_RDWR); 186 hashp->cbucket = -1; 187 if (!(dbp = (DB *)malloc(sizeof(DB)))) { 188 save_errno = errno; 189 hdestroy(hashp); 190 errno = save_errno; 191 return (NULL); 192 } 193 dbp->internal = hashp; 194 dbp->close = hash_close; 195 dbp->del = hash_delete; 196 dbp->fd = hash_fd; 197 dbp->get = hash_get; 198 dbp->put = hash_put; 199 dbp->seq = hash_seq; 200 dbp->sync = hash_sync; 201 dbp->type = DB_HASH; 202 203 #ifdef DEBUG 204 (void)fprintf(stderr, 205 "%s\n%s%p\n%s%d\n%s%d\n%s%d\n%s%d\n%s%d\n%s%d\n%s%d\n%s%d\n%s%d\n%s%x\n%s%x\n%s%d\n%s%d\n", 206 "init_htab:", 207 "TABLE POINTER ", hashp, 208 "BUCKET SIZE ", hashp->BSIZE, 209 "BUCKET SHIFT ", hashp->BSHIFT, 210 "DIRECTORY SIZE ", hashp->DSIZE, 211 "SEGMENT SIZE ", hashp->SGSIZE, 212 "SEGMENT SHIFT ", hashp->SSHIFT, 213 "FILL FACTOR ", hashp->FFACTOR, 214 "MAX BUCKET ", hashp->MAX_BUCKET, 215 "OVFL POINT ", hashp->OVFL_POINT, 216 "LAST FREED ", hashp->LAST_FREED, 217 "HIGH MASK ", hashp->HIGH_MASK, 218 "LOW MASK ", hashp->LOW_MASK, 219 "NSEGS ", hashp->nsegs, 220 "NKEYS ", hashp->NKEYS); 221 #endif 222 #ifdef HASH_STATISTICS 223 hash_overflows = hash_accesses = hash_collisions = hash_expansions = 0; 224 #endif 225 return (dbp); 226 227 error1: 228 if (hashp != NULL) 229 (void)_close(hashp->fp); 230 231 error0: 232 free(hashp); 233 errno = save_errno; 234 return (NULL); 235 } 236 237 static int 238 hash_close(DB *dbp) 239 { 240 HTAB *hashp; 241 int retval; 242 243 if (!dbp) 244 return (ERROR); 245 246 hashp = (HTAB *)dbp->internal; 247 retval = hdestroy(hashp); 248 free(dbp); 249 return (retval); 250 } 251 252 static int 253 hash_fd(const DB *dbp) 254 { 255 HTAB *hashp; 256 257 if (!dbp) 258 return (ERROR); 259 260 hashp = (HTAB *)dbp->internal; 261 if (hashp->fp == -1) { 262 errno = ENOENT; 263 return (-1); 264 } 265 return (hashp->fp); 266 } 267 268 /************************** LOCAL CREATION ROUTINES **********************/ 269 static HTAB * 270 init_hash(HTAB *hashp, const char *file, const HASHINFO *info) 271 { 272 struct stat statbuf; 273 int nelem; 274 275 nelem = 1; 276 hashp->NKEYS = 0; 277 hashp->LORDER = BYTE_ORDER; 278 hashp->BSIZE = DEF_BUCKET_SIZE; 279 hashp->BSHIFT = DEF_BUCKET_SHIFT; 280 hashp->SGSIZE = DEF_SEGSIZE; 281 hashp->SSHIFT = DEF_SEGSIZE_SHIFT; 282 hashp->DSIZE = DEF_DIRSIZE; 283 hashp->FFACTOR = DEF_FFACTOR; 284 hashp->hash = __default_hash; 285 memset(hashp->SPARES, 0, sizeof(hashp->SPARES)); 286 memset(hashp->BITMAPS, 0, sizeof (hashp->BITMAPS)); 287 288 /* Fix bucket size to be optimal for file system */ 289 if (file != NULL) { 290 if (stat(file, &statbuf)) 291 return (NULL); 292 hashp->BSIZE = statbuf.st_blksize; 293 if (hashp->BSIZE > MAX_BSIZE) 294 hashp->BSIZE = MAX_BSIZE; 295 hashp->BSHIFT = __log2(hashp->BSIZE); 296 } 297 298 if (info) { 299 if (info->bsize) { 300 /* Round pagesize up to power of 2 */ 301 hashp->BSHIFT = __log2(info->bsize); 302 hashp->BSIZE = 1 << hashp->BSHIFT; 303 if (hashp->BSIZE > MAX_BSIZE) { 304 errno = EINVAL; 305 return (NULL); 306 } 307 } 308 if (info->ffactor) 309 hashp->FFACTOR = info->ffactor; 310 if (info->hash) 311 hashp->hash = info->hash; 312 if (info->nelem) 313 nelem = info->nelem; 314 if (info->lorder) { 315 if (info->lorder != BIG_ENDIAN && 316 info->lorder != LITTLE_ENDIAN) { 317 errno = EINVAL; 318 return (NULL); 319 } 320 hashp->LORDER = info->lorder; 321 } 322 } 323 /* init_htab should destroy the table and set errno if it fails */ 324 if (init_htab(hashp, nelem)) 325 return (NULL); 326 else 327 return (hashp); 328 } 329 /* 330 * This calls alloc_segs which may run out of memory. Alloc_segs will destroy 331 * the table and set errno, so we just pass the error information along. 332 * 333 * Returns 0 on No Error 334 */ 335 static int 336 init_htab(HTAB *hashp, int nelem) 337 { 338 int nbuckets, nsegs, l2; 339 340 /* 341 * Divide number of elements by the fill factor and determine a 342 * desired number of buckets. Allocate space for the next greater 343 * power of two number of buckets. 344 */ 345 nelem = (nelem - 1) / hashp->FFACTOR + 1; 346 347 l2 = __log2(MAX(nelem, 2)); 348 nbuckets = 1 << l2; 349 350 hashp->SPARES[l2] = l2 + 1; 351 hashp->SPARES[l2 + 1] = l2 + 1; 352 hashp->OVFL_POINT = l2; 353 hashp->LAST_FREED = 2; 354 355 /* First bitmap page is at: splitpoint l2 page offset 1 */ 356 if (__ibitmap(hashp, OADDR_OF(l2, 1), l2 + 1, 0)) 357 return (-1); 358 359 hashp->MAX_BUCKET = hashp->LOW_MASK = nbuckets - 1; 360 hashp->HIGH_MASK = (nbuckets << 1) - 1; 361 hashp->HDRPAGES = ((MAX(sizeof(HASHHDR), MINHDRSIZE) - 1) >> 362 hashp->BSHIFT) + 1; 363 364 nsegs = (nbuckets - 1) / hashp->SGSIZE + 1; 365 nsegs = 1 << __log2(nsegs); 366 367 if (nsegs > hashp->DSIZE) 368 hashp->DSIZE = nsegs; 369 return (alloc_segs(hashp, nsegs)); 370 } 371 372 /********************** DESTROY/CLOSE ROUTINES ************************/ 373 374 /* 375 * Flushes any changes to the file if necessary and destroys the hashp 376 * structure, freeing all allocated space. 377 */ 378 static int 379 hdestroy(HTAB *hashp) 380 { 381 int i, save_errno; 382 383 save_errno = 0; 384 385 #ifdef HASH_STATISTICS 386 (void)fprintf(stderr, "hdestroy: accesses %ld collisions %ld\n", 387 hash_accesses, hash_collisions); 388 (void)fprintf(stderr, "hdestroy: expansions %ld\n", 389 hash_expansions); 390 (void)fprintf(stderr, "hdestroy: overflows %ld\n", 391 hash_overflows); 392 (void)fprintf(stderr, "keys %ld maxp %d segmentcount %d\n", 393 hashp->NKEYS, hashp->MAX_BUCKET, hashp->nsegs); 394 395 for (i = 0; i < NCACHED; i++) 396 (void)fprintf(stderr, 397 "spares[%d] = %d\n", i, hashp->SPARES[i]); 398 #endif 399 /* 400 * Call on buffer manager to free buffers, and if required, 401 * write them to disk. 402 */ 403 if (__buf_free(hashp, 1, hashp->save_file)) 404 save_errno = errno; 405 if (hashp->dir) { 406 free(*hashp->dir); /* Free initial segments */ 407 /* Free extra segments */ 408 while (hashp->exsegs--) 409 free(hashp->dir[--hashp->nsegs]); 410 free(hashp->dir); 411 } 412 if (flush_meta(hashp) && !save_errno) 413 save_errno = errno; 414 /* Free Bigmaps */ 415 for (i = 0; i < hashp->nmaps; i++) 416 if (hashp->mapp[i]) 417 free(hashp->mapp[i]); 418 if (hashp->tmp_key) 419 free(hashp->tmp_key); 420 if (hashp->tmp_buf) 421 free(hashp->tmp_buf); 422 423 if (hashp->fp != -1) { 424 if (hashp->save_file) 425 (void)_fsync(hashp->fp); 426 (void)_close(hashp->fp); 427 } 428 429 free(hashp); 430 431 if (save_errno) { 432 errno = save_errno; 433 return (ERROR); 434 } 435 return (SUCCESS); 436 } 437 /* 438 * Write modified pages to disk 439 * 440 * Returns: 441 * 0 == OK 442 * -1 ERROR 443 */ 444 static int 445 hash_sync(const DB *dbp, u_int32_t flags) 446 { 447 HTAB *hashp; 448 449 if (flags != 0) { 450 errno = EINVAL; 451 return (ERROR); 452 } 453 454 if (!dbp) 455 return (ERROR); 456 457 hashp = (HTAB *)dbp->internal; 458 if (!hashp->save_file) 459 return (0); 460 if (__buf_free(hashp, 0, 1) || flush_meta(hashp)) 461 return (ERROR); 462 if (hashp->fp != -1 && _fsync(hashp->fp) != 0) 463 return (ERROR); 464 hashp->new_file = 0; 465 return (0); 466 } 467 468 /* 469 * Returns: 470 * 0 == OK 471 * -1 indicates that errno should be set 472 */ 473 static int 474 flush_meta(HTAB *hashp) 475 { 476 HASHHDR *whdrp; 477 #if BYTE_ORDER == LITTLE_ENDIAN 478 HASHHDR whdr; 479 #endif 480 int fp, i, wsize; 481 482 if (!hashp->save_file) 483 return (0); 484 hashp->MAGIC = HASHMAGIC; 485 hashp->VERSION = HASHVERSION; 486 hashp->H_CHARKEY = hashp->hash(CHARKEY, sizeof(CHARKEY)); 487 488 fp = hashp->fp; 489 whdrp = &hashp->hdr; 490 #if BYTE_ORDER == LITTLE_ENDIAN 491 whdrp = &whdr; 492 swap_header_copy(&hashp->hdr, whdrp); 493 #endif 494 if ((wsize = pwrite(fp, whdrp, sizeof(HASHHDR), (off_t)0)) == -1) 495 return (-1); 496 else 497 if (wsize != sizeof(HASHHDR)) { 498 errno = EFTYPE; 499 hashp->error = errno; 500 return (-1); 501 } 502 for (i = 0; i < NCACHED; i++) 503 if (hashp->mapp[i]) 504 if (__put_page(hashp, (char *)hashp->mapp[i], 505 hashp->BITMAPS[i], 0, 1)) 506 return (-1); 507 return (0); 508 } 509 510 /*******************************SEARCH ROUTINES *****************************/ 511 /* 512 * All the access routines return 513 * 514 * Returns: 515 * 0 on SUCCESS 516 * 1 to indicate an external ERROR (i.e. key not found, etc) 517 * -1 to indicate an internal ERROR (i.e. out of memory, etc) 518 */ 519 static int 520 hash_get(const DB *dbp, const DBT *key, DBT *data, u_int32_t flag) 521 { 522 HTAB *hashp; 523 524 hashp = (HTAB *)dbp->internal; 525 if (flag) { 526 hashp->error = errno = EINVAL; 527 return (ERROR); 528 } 529 return (hash_access(hashp, HASH_GET, (DBT *)key, data)); 530 } 531 532 static int 533 hash_put(const DB *dbp, DBT *key, const DBT *data, u_int32_t flag) 534 { 535 HTAB *hashp; 536 537 hashp = (HTAB *)dbp->internal; 538 if (flag && flag != R_NOOVERWRITE) { 539 hashp->error = errno = EINVAL; 540 return (ERROR); 541 } 542 if ((hashp->flags & O_ACCMODE) == O_RDONLY) { 543 hashp->error = errno = EPERM; 544 return (ERROR); 545 } 546 return (hash_access(hashp, flag == R_NOOVERWRITE ? 547 HASH_PUTNEW : HASH_PUT, (DBT *)key, (DBT *)data)); 548 } 549 550 static int 551 hash_delete(const DB *dbp, const DBT *key, 552 u_int32_t flag) /* Ignored */ 553 { 554 HTAB *hashp; 555 556 hashp = (HTAB *)dbp->internal; 557 if (flag && flag != R_CURSOR) { 558 hashp->error = errno = EINVAL; 559 return (ERROR); 560 } 561 if ((hashp->flags & O_ACCMODE) == O_RDONLY) { 562 hashp->error = errno = EPERM; 563 return (ERROR); 564 } 565 return (hash_access(hashp, HASH_DELETE, (DBT *)key, NULL)); 566 } 567 568 /* 569 * Assume that hashp has been set in wrapper routine. 570 */ 571 static int 572 hash_access(HTAB *hashp, ACTION action, DBT *key, DBT *val) 573 { 574 BUFHEAD *rbufp; 575 BUFHEAD *bufp, *save_bufp; 576 u_int16_t *bp; 577 int n, ndx, off, size; 578 char *kp; 579 u_int16_t pageno; 580 581 #ifdef HASH_STATISTICS 582 hash_accesses++; 583 #endif 584 585 off = hashp->BSIZE; 586 size = key->size; 587 kp = (char *)key->data; 588 rbufp = __get_buf(hashp, __call_hash(hashp, kp, size), NULL, 0); 589 if (!rbufp) 590 return (ERROR); 591 save_bufp = rbufp; 592 593 /* Pin the bucket chain */ 594 rbufp->flags |= BUF_PIN; 595 for (bp = (u_int16_t *)rbufp->page, n = *bp++, ndx = 1; ndx < n;) 596 if (bp[1] >= REAL_KEY) { 597 /* Real key/data pair */ 598 if (size == off - *bp && 599 memcmp(kp, rbufp->page + *bp, size) == 0) 600 goto found; 601 off = bp[1]; 602 #ifdef HASH_STATISTICS 603 hash_collisions++; 604 #endif 605 bp += 2; 606 ndx += 2; 607 } else if (bp[1] == OVFLPAGE) { 608 rbufp = __get_buf(hashp, *bp, rbufp, 0); 609 if (!rbufp) { 610 save_bufp->flags &= ~BUF_PIN; 611 return (ERROR); 612 } 613 /* FOR LOOP INIT */ 614 bp = (u_int16_t *)rbufp->page; 615 n = *bp++; 616 ndx = 1; 617 off = hashp->BSIZE; 618 } else if (bp[1] < REAL_KEY) { 619 if ((ndx = 620 __find_bigpair(hashp, rbufp, ndx, kp, size)) > 0) 621 goto found; 622 if (ndx == -2) { 623 bufp = rbufp; 624 if (!(pageno = 625 __find_last_page(hashp, &bufp))) { 626 ndx = 0; 627 rbufp = bufp; 628 break; /* FOR */ 629 } 630 rbufp = __get_buf(hashp, pageno, bufp, 0); 631 if (!rbufp) { 632 save_bufp->flags &= ~BUF_PIN; 633 return (ERROR); 634 } 635 /* FOR LOOP INIT */ 636 bp = (u_int16_t *)rbufp->page; 637 n = *bp++; 638 ndx = 1; 639 off = hashp->BSIZE; 640 } else { 641 save_bufp->flags &= ~BUF_PIN; 642 return (ERROR); 643 } 644 } 645 646 /* Not found */ 647 switch (action) { 648 case HASH_PUT: 649 case HASH_PUTNEW: 650 if (__addel(hashp, rbufp, key, val)) { 651 save_bufp->flags &= ~BUF_PIN; 652 return (ERROR); 653 } else { 654 save_bufp->flags &= ~BUF_PIN; 655 return (SUCCESS); 656 } 657 case HASH_GET: 658 case HASH_DELETE: 659 default: 660 save_bufp->flags &= ~BUF_PIN; 661 return (ABNORMAL); 662 } 663 664 found: 665 switch (action) { 666 case HASH_PUTNEW: 667 save_bufp->flags &= ~BUF_PIN; 668 return (ABNORMAL); 669 case HASH_GET: 670 bp = (u_int16_t *)rbufp->page; 671 if (bp[ndx + 1] < REAL_KEY) { 672 if (__big_return(hashp, rbufp, ndx, val, 0)) 673 return (ERROR); 674 } else { 675 val->data = (u_char *)rbufp->page + (int)bp[ndx + 1]; 676 val->size = bp[ndx] - bp[ndx + 1]; 677 } 678 break; 679 case HASH_PUT: 680 if ((__delpair(hashp, rbufp, ndx)) || 681 (__addel(hashp, rbufp, key, val))) { 682 save_bufp->flags &= ~BUF_PIN; 683 return (ERROR); 684 } 685 break; 686 case HASH_DELETE: 687 if (__delpair(hashp, rbufp, ndx)) 688 return (ERROR); 689 break; 690 default: 691 abort(); 692 } 693 save_bufp->flags &= ~BUF_PIN; 694 return (SUCCESS); 695 } 696 697 static int 698 hash_seq(const DB *dbp, DBT *key, DBT *data, u_int32_t flag) 699 { 700 u_int32_t bucket; 701 BUFHEAD *bufp; 702 HTAB *hashp; 703 u_int16_t *bp, ndx; 704 705 hashp = (HTAB *)dbp->internal; 706 if (flag && flag != R_FIRST && flag != R_NEXT) { 707 hashp->error = errno = EINVAL; 708 return (ERROR); 709 } 710 #ifdef HASH_STATISTICS 711 hash_accesses++; 712 #endif 713 if ((hashp->cbucket < 0) || (flag == R_FIRST)) { 714 hashp->cbucket = 0; 715 hashp->cndx = 1; 716 hashp->cpage = NULL; 717 } 718 next_bucket: 719 for (bp = NULL; !bp || !bp[0]; ) { 720 if (!(bufp = hashp->cpage)) { 721 for (bucket = hashp->cbucket; 722 bucket <= hashp->MAX_BUCKET; 723 bucket++, hashp->cndx = 1) { 724 bufp = __get_buf(hashp, bucket, NULL, 0); 725 if (!bufp) 726 return (ERROR); 727 hashp->cpage = bufp; 728 bp = (u_int16_t *)bufp->page; 729 if (bp[0]) 730 break; 731 } 732 hashp->cbucket = bucket; 733 if ((u_int32_t)hashp->cbucket > hashp->MAX_BUCKET) { 734 hashp->cbucket = -1; 735 return (ABNORMAL); 736 } 737 } else { 738 bp = (u_int16_t *)hashp->cpage->page; 739 if (flag == R_NEXT || flag == 0) { 740 hashp->cndx += 2; 741 if (hashp->cndx > bp[0]) { 742 hashp->cpage = NULL; 743 hashp->cbucket++; 744 hashp->cndx = 1; 745 goto next_bucket; 746 } 747 } 748 } 749 750 #ifdef DEBUG 751 assert(bp); 752 assert(bufp); 753 #endif 754 while (bp[hashp->cndx + 1] == OVFLPAGE) { 755 bufp = hashp->cpage = 756 __get_buf(hashp, bp[hashp->cndx], bufp, 0); 757 if (!bufp) 758 return (ERROR); 759 bp = (u_int16_t *)(bufp->page); 760 hashp->cndx = 1; 761 } 762 if (!bp[0]) { 763 hashp->cpage = NULL; 764 ++hashp->cbucket; 765 } 766 } 767 ndx = hashp->cndx; 768 if (bp[ndx + 1] < REAL_KEY) { 769 if (__big_keydata(hashp, bufp, key, data, 1)) 770 return (ERROR); 771 } else { 772 if (hashp->cpage == NULL) 773 return (ERROR); 774 key->data = (u_char *)hashp->cpage->page + bp[ndx]; 775 key->size = (ndx > 1 ? bp[ndx - 1] : hashp->BSIZE) - bp[ndx]; 776 data->data = (u_char *)hashp->cpage->page + bp[ndx + 1]; 777 data->size = bp[ndx] - bp[ndx + 1]; 778 } 779 return (SUCCESS); 780 } 781 782 /********************************* UTILITIES ************************/ 783 784 /* 785 * Returns: 786 * 0 ==> OK 787 * -1 ==> Error 788 */ 789 int 790 __expand_table(HTAB *hashp) 791 { 792 u_int32_t old_bucket, new_bucket; 793 int dirsize, new_segnum, spare_ndx; 794 795 #ifdef HASH_STATISTICS 796 hash_expansions++; 797 #endif 798 new_bucket = ++hashp->MAX_BUCKET; 799 old_bucket = (hashp->MAX_BUCKET & hashp->LOW_MASK); 800 801 new_segnum = new_bucket >> hashp->SSHIFT; 802 803 /* Check if we need a new segment */ 804 if (new_segnum >= hashp->nsegs) { 805 /* Check if we need to expand directory */ 806 if (new_segnum >= hashp->DSIZE) { 807 /* Reallocate directory */ 808 dirsize = hashp->DSIZE * sizeof(SEGMENT *); 809 if (!hash_realloc(&hashp->dir, dirsize, dirsize << 1)) 810 return (-1); 811 hashp->DSIZE = dirsize << 1; 812 } 813 if ((hashp->dir[new_segnum] = 814 calloc(hashp->SGSIZE, sizeof(SEGMENT))) == NULL) 815 return (-1); 816 hashp->exsegs++; 817 hashp->nsegs++; 818 } 819 /* 820 * If the split point is increasing (MAX_BUCKET's log base 2 821 * * increases), we need to copy the current contents of the spare 822 * split bucket to the next bucket. 823 */ 824 spare_ndx = __log2(hashp->MAX_BUCKET + 1); 825 if (spare_ndx > hashp->OVFL_POINT) { 826 hashp->SPARES[spare_ndx] = hashp->SPARES[hashp->OVFL_POINT]; 827 hashp->OVFL_POINT = spare_ndx; 828 } 829 830 if (new_bucket > hashp->HIGH_MASK) { 831 /* Starting a new doubling */ 832 hashp->LOW_MASK = hashp->HIGH_MASK; 833 hashp->HIGH_MASK = new_bucket | hashp->LOW_MASK; 834 } 835 /* Relocate records to the new bucket */ 836 return (__split_page(hashp, old_bucket, new_bucket)); 837 } 838 839 /* 840 * If realloc guarantees that the pointer is not destroyed if the realloc 841 * fails, then this routine can go away. 842 */ 843 static void * 844 hash_realloc(SEGMENT **p_ptr, int oldsize, int newsize) 845 { 846 void *p; 847 848 if ( (p = malloc(newsize)) ) { 849 memmove(p, *p_ptr, oldsize); 850 memset((char *)p + oldsize, 0, newsize - oldsize); 851 free(*p_ptr); 852 *p_ptr = p; 853 } 854 return (p); 855 } 856 857 u_int32_t 858 __call_hash(HTAB *hashp, char *k, int len) 859 { 860 unsigned int n, bucket; 861 862 n = hashp->hash(k, len); 863 bucket = n & hashp->HIGH_MASK; 864 if (bucket > hashp->MAX_BUCKET) 865 bucket = bucket & hashp->LOW_MASK; 866 return (bucket); 867 } 868 869 /* 870 * Allocate segment table. On error, destroy the table and set errno. 871 * 872 * Returns 0 on success 873 */ 874 static int 875 alloc_segs(HTAB *hashp, int nsegs) 876 { 877 int i; 878 SEGMENT store; 879 880 int save_errno; 881 882 if ((hashp->dir = 883 calloc(hashp->DSIZE, sizeof(SEGMENT *))) == NULL) { 884 save_errno = errno; 885 (void)hdestroy(hashp); 886 errno = save_errno; 887 return (-1); 888 } 889 hashp->nsegs = nsegs; 890 if (nsegs == 0) 891 return (0); 892 /* Allocate segments */ 893 if ((store = calloc(nsegs << hashp->SSHIFT, sizeof(SEGMENT))) == NULL) { 894 save_errno = errno; 895 (void)hdestroy(hashp); 896 errno = save_errno; 897 return (-1); 898 } 899 for (i = 0; i < nsegs; i++) 900 hashp->dir[i] = &store[i << hashp->SSHIFT]; 901 return (0); 902 } 903 904 #if BYTE_ORDER == LITTLE_ENDIAN 905 /* 906 * Hashp->hdr needs to be byteswapped. 907 */ 908 static void 909 swap_header_copy(HASHHDR *srcp, HASHHDR *destp) 910 { 911 int i; 912 913 P_32_COPY(srcp->magic, destp->magic); 914 P_32_COPY(srcp->version, destp->version); 915 P_32_COPY(srcp->lorder, destp->lorder); 916 P_32_COPY(srcp->bsize, destp->bsize); 917 P_32_COPY(srcp->bshift, destp->bshift); 918 P_32_COPY(srcp->dsize, destp->dsize); 919 P_32_COPY(srcp->ssize, destp->ssize); 920 P_32_COPY(srcp->sshift, destp->sshift); 921 P_32_COPY(srcp->ovfl_point, destp->ovfl_point); 922 P_32_COPY(srcp->last_freed, destp->last_freed); 923 P_32_COPY(srcp->max_bucket, destp->max_bucket); 924 P_32_COPY(srcp->high_mask, destp->high_mask); 925 P_32_COPY(srcp->low_mask, destp->low_mask); 926 P_32_COPY(srcp->ffactor, destp->ffactor); 927 P_32_COPY(srcp->nkeys, destp->nkeys); 928 P_32_COPY(srcp->hdrpages, destp->hdrpages); 929 P_32_COPY(srcp->h_charkey, destp->h_charkey); 930 for (i = 0; i < NCACHED; i++) { 931 P_32_COPY(srcp->spares[i], destp->spares[i]); 932 P_16_COPY(srcp->bitmaps[i], destp->bitmaps[i]); 933 } 934 } 935 936 static void 937 swap_header(HTAB *hashp) 938 { 939 HASHHDR *hdrp; 940 int i; 941 942 hdrp = &hashp->hdr; 943 944 M_32_SWAP(hdrp->magic); 945 M_32_SWAP(hdrp->version); 946 M_32_SWAP(hdrp->lorder); 947 M_32_SWAP(hdrp->bsize); 948 M_32_SWAP(hdrp->bshift); 949 M_32_SWAP(hdrp->dsize); 950 M_32_SWAP(hdrp->ssize); 951 M_32_SWAP(hdrp->sshift); 952 M_32_SWAP(hdrp->ovfl_point); 953 M_32_SWAP(hdrp->last_freed); 954 M_32_SWAP(hdrp->max_bucket); 955 M_32_SWAP(hdrp->high_mask); 956 M_32_SWAP(hdrp->low_mask); 957 M_32_SWAP(hdrp->ffactor); 958 M_32_SWAP(hdrp->nkeys); 959 M_32_SWAP(hdrp->hdrpages); 960 M_32_SWAP(hdrp->h_charkey); 961 for (i = 0; i < NCACHED; i++) { 962 M_32_SWAP(hdrp->spares[i]); 963 M_16_SWAP(hdrp->bitmaps[i]); 964 } 965 } 966 #endif 967