1 /* $NetBSD: hash_page.c,v 1.23 2008/09/11 12:58:00 joerg Exp $ */ 2 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 HAVE_NBTOOL_CONFIG_H 36 #include "nbtool_config.h" 37 #endif 38 39 #include <sys/cdefs.h> 40 __RCSID("$NetBSD: hash_page.c,v 1.23 2008/09/11 12:58:00 joerg Exp $"); 41 42 /* 43 * PACKAGE: hashing 44 * 45 * DESCRIPTION: 46 * Page manipulation for hashing package. 47 * 48 * ROUTINES: 49 * 50 * External 51 * __get_page 52 * __add_ovflpage 53 * Internal 54 * overflow_page 55 * open_temp 56 */ 57 58 #include "namespace.h" 59 60 #include <sys/types.h> 61 62 #include <errno.h> 63 #include <fcntl.h> 64 #include <signal.h> 65 #include <stdio.h> 66 #include <stdlib.h> 67 #include <string.h> 68 #include <unistd.h> 69 #include <paths.h> 70 #include <assert.h> 71 72 #include <db.h> 73 #include "hash.h" 74 #include "page.h" 75 #include "extern.h" 76 77 static uint32_t *fetch_bitmap(HTAB *, int); 78 static uint32_t first_free(uint32_t); 79 static int open_temp(HTAB *); 80 static uint16_t overflow_page(HTAB *); 81 static void putpair(char *, const DBT *, const DBT *); 82 static void squeeze_key(uint16_t *, const DBT *, const DBT *); 83 static int ugly_split(HTAB *, uint32_t, BUFHEAD *, BUFHEAD *, int, int); 84 85 #define PAGE_INIT(P) { \ 86 ((uint16_t *)(void *)(P))[0] = 0; \ 87 temp = 3 * sizeof(uint16_t); \ 88 _DIAGASSERT(hashp->BSIZE >= temp); \ 89 ((uint16_t *)(void *)(P))[1] = (uint16_t)(hashp->BSIZE - temp); \ 90 ((uint16_t *)(void *)(P))[2] = hashp->BSIZE; \ 91 } 92 93 /* 94 * This is called AFTER we have verified that there is room on the page for 95 * the pair (PAIRFITS has returned true) so we go right ahead and start moving 96 * stuff on. 97 */ 98 static void 99 putpair(char *p, const DBT *key, const DBT *val) 100 { 101 uint16_t *bp, n, off; 102 size_t temp; 103 104 bp = (uint16_t *)(void *)p; 105 106 /* Enter the key first. */ 107 n = bp[0]; 108 109 temp = OFFSET(bp); 110 _DIAGASSERT(temp >= key->size); 111 off = (uint16_t)(temp - key->size); 112 memmove(p + off, key->data, key->size); 113 bp[++n] = off; 114 115 /* Now the data. */ 116 _DIAGASSERT(off >= val->size); 117 off -= (uint16_t)val->size; 118 memmove(p + off, val->data, val->size); 119 bp[++n] = off; 120 121 /* Adjust page info. */ 122 bp[0] = n; 123 temp = (n + 3) * sizeof(uint16_t); 124 _DIAGASSERT(off >= temp); 125 bp[n + 1] = (uint16_t)(off - temp); 126 bp[n + 2] = off; 127 } 128 129 /* 130 * Returns: 131 * 0 OK 132 * -1 error 133 */ 134 int 135 __delpair(HTAB *hashp, BUFHEAD *bufp, int ndx) 136 { 137 uint16_t *bp, newoff; 138 int n; 139 uint16_t pairlen; 140 size_t temp; 141 142 bp = (uint16_t *)(void *)bufp->page; 143 n = bp[0]; 144 145 if (bp[ndx + 1] < REAL_KEY) 146 return (__big_delete(hashp, bufp)); 147 if (ndx != 1) 148 newoff = bp[ndx - 1]; 149 else 150 newoff = hashp->BSIZE; 151 pairlen = newoff - bp[ndx + 1]; 152 153 if (ndx != (n - 1)) { 154 /* Hard Case -- need to shuffle keys */ 155 int i; 156 char *src = bufp->page + (int)OFFSET(bp); 157 char *dst = src + (int)pairlen; 158 memmove(dst, src, (size_t)(bp[ndx + 1] - OFFSET(bp))); 159 160 /* Now adjust the pointers */ 161 for (i = ndx + 2; i <= n; i += 2) { 162 if (bp[i + 1] == OVFLPAGE) { 163 bp[i - 2] = bp[i]; 164 bp[i - 1] = bp[i + 1]; 165 } else { 166 bp[i - 2] = bp[i] + pairlen; 167 bp[i - 1] = bp[i + 1] + pairlen; 168 } 169 } 170 } 171 /* Finally adjust the page data */ 172 bp[n] = OFFSET(bp) + pairlen; 173 temp = bp[n + 1] + pairlen + 2 * sizeof(uint16_t); 174 _DIAGASSERT(temp <= 0xffff); 175 bp[n - 1] = (uint16_t)temp; 176 bp[0] = n - 2; 177 hashp->NKEYS--; 178 179 bufp->flags |= BUF_MOD; 180 return (0); 181 } 182 /* 183 * Returns: 184 * 0 ==> OK 185 * -1 ==> Error 186 */ 187 int 188 __split_page(HTAB *hashp, uint32_t obucket, uint32_t nbucket) 189 { 190 BUFHEAD *new_bufp, *old_bufp; 191 uint16_t *ino; 192 char *np; 193 DBT key, val; 194 int n, ndx, retval; 195 uint16_t copyto, diff, off, moved; 196 char *op; 197 size_t temp; 198 199 copyto = (uint16_t)hashp->BSIZE; 200 off = (uint16_t)hashp->BSIZE; 201 old_bufp = __get_buf(hashp, obucket, NULL, 0); 202 if (old_bufp == NULL) 203 return (-1); 204 new_bufp = __get_buf(hashp, nbucket, NULL, 0); 205 if (new_bufp == NULL) 206 return (-1); 207 208 old_bufp->flags |= (BUF_MOD | BUF_PIN); 209 new_bufp->flags |= (BUF_MOD | BUF_PIN); 210 211 ino = (uint16_t *)(void *)(op = old_bufp->page); 212 np = new_bufp->page; 213 214 moved = 0; 215 216 for (n = 1, ndx = 1; n < ino[0]; n += 2) { 217 if (ino[n + 1] < REAL_KEY) { 218 retval = ugly_split(hashp, obucket, old_bufp, new_bufp, 219 (int)copyto, (int)moved); 220 old_bufp->flags &= ~BUF_PIN; 221 new_bufp->flags &= ~BUF_PIN; 222 return (retval); 223 224 } 225 key.data = (uint8_t *)op + ino[n]; 226 key.size = off - ino[n]; 227 228 if (__call_hash(hashp, key.data, (int)key.size) == obucket) { 229 /* Don't switch page */ 230 diff = copyto - off; 231 if (diff) { 232 copyto = ino[n + 1] + diff; 233 memmove(op + copyto, op + ino[n + 1], 234 (size_t)(off - ino[n + 1])); 235 ino[ndx] = copyto + ino[n] - ino[n + 1]; 236 ino[ndx + 1] = copyto; 237 } else 238 copyto = ino[n + 1]; 239 ndx += 2; 240 } else { 241 /* Switch page */ 242 val.data = (uint8_t *)op + ino[n + 1]; 243 val.size = ino[n] - ino[n + 1]; 244 putpair(np, &key, &val); 245 moved += 2; 246 } 247 248 off = ino[n + 1]; 249 } 250 251 /* Now clean up the page */ 252 ino[0] -= moved; 253 temp = sizeof(uint16_t) * (ino[0] + 3); 254 _DIAGASSERT(copyto >= temp); 255 FREESPACE(ino) = (uint16_t)(copyto - temp); 256 OFFSET(ino) = copyto; 257 258 #ifdef DEBUG3 259 (void)fprintf(stderr, "split %d/%d\n", 260 ((uint16_t *)np)[0] / 2, 261 ((uint16_t *)op)[0] / 2); 262 #endif 263 /* unpin both pages */ 264 old_bufp->flags &= ~BUF_PIN; 265 new_bufp->flags &= ~BUF_PIN; 266 return (0); 267 } 268 269 /* 270 * Called when we encounter an overflow or big key/data page during split 271 * handling. This is special cased since we have to begin checking whether 272 * the key/data pairs fit on their respective pages and because we may need 273 * overflow pages for both the old and new pages. 274 * 275 * The first page might be a page with regular key/data pairs in which case 276 * we have a regular overflow condition and just need to go on to the next 277 * page or it might be a big key/data pair in which case we need to fix the 278 * big key/data pair. 279 * 280 * Returns: 281 * 0 ==> success 282 * -1 ==> failure 283 */ 284 static int 285 ugly_split( 286 HTAB *hashp, 287 uint32_t obucket, /* Same as __split_page. */ 288 BUFHEAD *old_bufp, 289 BUFHEAD *new_bufp, 290 int copyto, /* First byte on page which contains key/data values. */ 291 int moved /* Number of pairs moved to new page. */ 292 ) 293 { 294 BUFHEAD *bufp; /* Buffer header for ino */ 295 uint16_t *ino; /* Page keys come off of */ 296 uint16_t *np; /* New page */ 297 uint16_t *op; /* Page keys go on to if they aren't moving */ 298 size_t temp; 299 300 BUFHEAD *last_bfp; /* Last buf header OVFL needing to be freed */ 301 DBT key, val; 302 SPLIT_RETURN ret; 303 uint16_t n, off, ov_addr, scopyto; 304 char *cino; /* Character value of ino */ 305 306 bufp = old_bufp; 307 ino = (uint16_t *)(void *)old_bufp->page; 308 np = (uint16_t *)(void *)new_bufp->page; 309 op = (uint16_t *)(void *)old_bufp->page; 310 last_bfp = NULL; 311 scopyto = (uint16_t)copyto; /* ANSI */ 312 313 n = ino[0] - 1; 314 while (n < ino[0]) { 315 if (ino[2] < REAL_KEY && ino[2] != OVFLPAGE) { 316 if (__big_split(hashp, old_bufp, 317 new_bufp, bufp, (int)bufp->addr, obucket, &ret)) 318 return (-1); 319 old_bufp = ret.oldp; 320 if (!old_bufp) 321 return (-1); 322 op = (uint16_t *)(void *)old_bufp->page; 323 new_bufp = ret.newp; 324 if (!new_bufp) 325 return (-1); 326 np = (uint16_t *)(void *)new_bufp->page; 327 bufp = ret.nextp; 328 if (!bufp) 329 return (0); 330 cino = (char *)bufp->page; 331 ino = (uint16_t *)(void *)cino; 332 last_bfp = ret.nextp; 333 } else if (ino[n + 1] == OVFLPAGE) { 334 ov_addr = ino[n]; 335 /* 336 * Fix up the old page -- the extra 2 are the fields 337 * which contained the overflow information. 338 */ 339 ino[0] -= (moved + 2); 340 temp = sizeof(uint16_t) * (ino[0] + 3); 341 _DIAGASSERT(scopyto >= temp); 342 FREESPACE(ino) = (uint16_t)(scopyto - temp); 343 OFFSET(ino) = scopyto; 344 345 bufp = __get_buf(hashp, (uint32_t)ov_addr, bufp, 0); 346 if (!bufp) 347 return (-1); 348 349 ino = (uint16_t *)(void *)bufp->page; 350 n = 1; 351 scopyto = hashp->BSIZE; 352 moved = 0; 353 354 if (last_bfp) 355 __free_ovflpage(hashp, last_bfp); 356 last_bfp = bufp; 357 } 358 /* Move regular sized pairs of there are any */ 359 off = hashp->BSIZE; 360 for (n = 1; (n < ino[0]) && (ino[n + 1] >= REAL_KEY); n += 2) { 361 cino = (char *)(void *)ino; 362 key.data = (uint8_t *)cino + ino[n]; 363 key.size = off - ino[n]; 364 val.data = (uint8_t *)cino + ino[n + 1]; 365 val.size = ino[n] - ino[n + 1]; 366 off = ino[n + 1]; 367 368 if (__call_hash(hashp, key.data, (int)key.size) == obucket) { 369 /* Keep on old page */ 370 if (PAIRFITS(op, (&key), (&val))) 371 putpair((char *)(void *)op, &key, &val); 372 else { 373 old_bufp = 374 __add_ovflpage(hashp, old_bufp); 375 if (!old_bufp) 376 return (-1); 377 op = (uint16_t *)(void *)old_bufp->page; 378 putpair((char *)(void *)op, &key, &val); 379 } 380 old_bufp->flags |= BUF_MOD; 381 } else { 382 /* Move to new page */ 383 if (PAIRFITS(np, (&key), (&val))) 384 putpair((char *)(void *)np, &key, &val); 385 else { 386 new_bufp = 387 __add_ovflpage(hashp, new_bufp); 388 if (!new_bufp) 389 return (-1); 390 np = (uint16_t *)(void *)new_bufp->page; 391 putpair((char *)(void *)np, &key, &val); 392 } 393 new_bufp->flags |= BUF_MOD; 394 } 395 } 396 } 397 if (last_bfp) 398 __free_ovflpage(hashp, last_bfp); 399 return (0); 400 } 401 402 /* 403 * Add the given pair to the page 404 * 405 * Returns: 406 * 0 ==> OK 407 * 1 ==> failure 408 */ 409 int 410 __addel(HTAB *hashp, BUFHEAD *bufp, const DBT *key, const DBT *val) 411 { 412 uint16_t *bp, *sop; 413 int do_expand; 414 415 bp = (uint16_t *)(void *)bufp->page; 416 do_expand = 0; 417 while (bp[0] && (bp[2] < REAL_KEY || bp[bp[0]] < REAL_KEY)) 418 /* Exception case */ 419 if (bp[2] == FULL_KEY_DATA && bp[0] == 2) 420 /* This is the last page of a big key/data pair 421 and we need to add another page */ 422 break; 423 else if (bp[2] < REAL_KEY && bp[bp[0]] != OVFLPAGE) { 424 bufp = __get_buf(hashp, (uint32_t)bp[bp[0] - 1], bufp, 425 0); 426 if (!bufp) 427 return (-1); 428 bp = (uint16_t *)(void *)bufp->page; 429 } else if (bp[bp[0]] != OVFLPAGE) { 430 /* Short key/data pairs, no more pages */ 431 break; 432 } else { 433 /* Try to squeeze key on this page */ 434 if (bp[2] >= REAL_KEY && 435 FREESPACE(bp) >= PAIRSIZE(key, val)) { 436 squeeze_key(bp, key, val); 437 goto stats; 438 } else { 439 bufp = __get_buf(hashp, 440 (uint32_t)bp[bp[0] - 1], bufp, 0); 441 if (!bufp) 442 return (-1); 443 bp = (uint16_t *)(void *)bufp->page; 444 } 445 } 446 447 if (PAIRFITS(bp, key, val)) 448 putpair(bufp->page, key, val); 449 else { 450 do_expand = 1; 451 bufp = __add_ovflpage(hashp, bufp); 452 if (!bufp) 453 return (-1); 454 sop = (uint16_t *)(void *)bufp->page; 455 456 if (PAIRFITS(sop, key, val)) 457 putpair((char *)(void *)sop, key, val); 458 else 459 if (__big_insert(hashp, bufp, key, val)) 460 return (-1); 461 } 462 stats: 463 bufp->flags |= BUF_MOD; 464 /* 465 * If the average number of keys per bucket exceeds the fill factor, 466 * expand the table. 467 */ 468 hashp->NKEYS++; 469 if (do_expand || 470 (hashp->NKEYS / (hashp->MAX_BUCKET + 1) > hashp->FFACTOR)) 471 return (__expand_table(hashp)); 472 return (0); 473 } 474 475 /* 476 * 477 * Returns: 478 * pointer on success 479 * NULL on error 480 */ 481 BUFHEAD * 482 __add_ovflpage(HTAB *hashp, BUFHEAD *bufp) 483 { 484 uint16_t *sp; 485 uint16_t ndx, ovfl_num; 486 size_t temp; 487 #ifdef DEBUG1 488 int tmp1, tmp2; 489 #endif 490 sp = (uint16_t *)(void *)bufp->page; 491 492 /* Check if we are dynamically determining the fill factor */ 493 if (hashp->FFACTOR == DEF_FFACTOR) { 494 hashp->FFACTOR = (uint32_t)sp[0] >> 1; 495 if (hashp->FFACTOR < MIN_FFACTOR) 496 hashp->FFACTOR = MIN_FFACTOR; 497 } 498 bufp->flags |= BUF_MOD; 499 ovfl_num = overflow_page(hashp); 500 #ifdef DEBUG1 501 tmp1 = bufp->addr; 502 tmp2 = bufp->ovfl ? bufp->ovfl->addr : 0; 503 #endif 504 if (!ovfl_num || !(bufp->ovfl = __get_buf(hashp, (uint32_t)ovfl_num, 505 bufp, 1))) 506 return (NULL); 507 bufp->ovfl->flags |= BUF_MOD; 508 #ifdef DEBUG1 509 (void)fprintf(stderr, "ADDOVFLPAGE: %d->ovfl was %d is now %d\n", 510 tmp1, tmp2, bufp->ovfl->addr); 511 #endif 512 ndx = sp[0]; 513 /* 514 * Since a pair is allocated on a page only if there's room to add 515 * an overflow page, we know that the OVFL information will fit on 516 * the page. 517 */ 518 sp[ndx + 4] = OFFSET(sp); 519 temp = FREESPACE(sp); 520 _DIAGASSERT(temp >= OVFLSIZE); 521 sp[ndx + 3] = (uint16_t)(temp - OVFLSIZE); 522 sp[ndx + 1] = ovfl_num; 523 sp[ndx + 2] = OVFLPAGE; 524 sp[0] = ndx + 2; 525 #ifdef HASH_STATISTICS 526 hash_overflows++; 527 #endif 528 return (bufp->ovfl); 529 } 530 531 /* 532 * Returns: 533 * 0 indicates SUCCESS 534 * -1 indicates FAILURE 535 */ 536 int 537 __get_page(HTAB *hashp, char *p, uint32_t bucket, int is_bucket, int is_disk, 538 int is_bitmap) 539 { 540 int fd, page, size; 541 ssize_t rsize; 542 uint16_t *bp; 543 size_t temp; 544 545 fd = hashp->fp; 546 size = hashp->BSIZE; 547 548 if ((fd == -1) || !is_disk) { 549 PAGE_INIT(p); 550 return (0); 551 } 552 if (is_bucket) 553 page = BUCKET_TO_PAGE(bucket); 554 else 555 page = OADDR_TO_PAGE(bucket); 556 if ((rsize = pread(fd, p, (size_t)size, (off_t)page << hashp->BSHIFT)) == -1) 557 return (-1); 558 bp = (uint16_t *)(void *)p; 559 if (!rsize) 560 bp[0] = 0; /* We hit the EOF, so initialize a new page */ 561 else 562 if (rsize != size) { 563 errno = EFTYPE; 564 return (-1); 565 } 566 if (!is_bitmap && !bp[0]) { 567 PAGE_INIT(p); 568 } else 569 if (hashp->LORDER != BYTE_ORDER) { 570 int i, max; 571 572 if (is_bitmap) { 573 max = (uint32_t)hashp->BSIZE >> 2; /* divide by 4 */ 574 for (i = 0; i < max; i++) 575 M_32_SWAP(((int *)(void *)p)[i]); 576 } else { 577 M_16_SWAP(bp[0]); 578 max = bp[0] + 2; 579 for (i = 1; i <= max; i++) 580 M_16_SWAP(bp[i]); 581 } 582 } 583 return (0); 584 } 585 586 /* 587 * Write page p to disk 588 * 589 * Returns: 590 * 0 ==> OK 591 * -1 ==>failure 592 */ 593 int 594 __put_page(HTAB *hashp, char *p, uint32_t bucket, int is_bucket, int is_bitmap) 595 { 596 int fd, page, size; 597 ssize_t wsize; 598 599 size = hashp->BSIZE; 600 if ((hashp->fp == -1) && open_temp(hashp)) 601 return (-1); 602 fd = hashp->fp; 603 604 if (hashp->LORDER != BYTE_ORDER) { 605 int i; 606 int max; 607 608 if (is_bitmap) { 609 max = (uint32_t)hashp->BSIZE >> 2; /* divide by 4 */ 610 for (i = 0; i < max; i++) 611 M_32_SWAP(((int *)(void *)p)[i]); 612 } else { 613 max = ((uint16_t *)(void *)p)[0] + 2; 614 for (i = 0; i <= max; i++) 615 M_16_SWAP(((uint16_t *)(void *)p)[i]); 616 } 617 } 618 if (is_bucket) 619 page = BUCKET_TO_PAGE(bucket); 620 else 621 page = OADDR_TO_PAGE(bucket); 622 if ((wsize = pwrite(fd, p, (size_t)size, (off_t)page << hashp->BSHIFT)) == -1) 623 /* Errno is set */ 624 return (-1); 625 if (wsize != size) { 626 errno = EFTYPE; 627 return (-1); 628 } 629 return (0); 630 } 631 632 #define BYTE_MASK ((1 << INT_BYTE_SHIFT) -1) 633 /* 634 * Initialize a new bitmap page. Bitmap pages are left in memory 635 * once they are read in. 636 */ 637 int 638 __ibitmap(HTAB *hashp, int pnum, int nbits, int ndx) 639 { 640 uint32_t *ip; 641 int clearbytes, clearints; 642 643 if ((ip = malloc((size_t)hashp->BSIZE)) == NULL) 644 return (1); 645 hashp->nmaps++; 646 clearints = ((uint32_t)(nbits - 1) >> INT_BYTE_SHIFT) + 1; 647 clearbytes = clearints << INT_TO_BYTE; 648 (void)memset(ip, 0, (size_t)clearbytes); 649 (void)memset(((char *)(void *)ip) + clearbytes, 0xFF, 650 (size_t)(hashp->BSIZE - clearbytes)); 651 ip[clearints - 1] = ALL_SET << (nbits & BYTE_MASK); 652 SETBIT(ip, 0); 653 hashp->BITMAPS[ndx] = (uint16_t)pnum; 654 hashp->mapp[ndx] = ip; 655 return (0); 656 } 657 658 static uint32_t 659 first_free(uint32_t map) 660 { 661 uint32_t i, mask; 662 663 mask = 0x1; 664 for (i = 0; i < BITS_PER_MAP; i++) { 665 if (!(mask & map)) 666 return (i); 667 mask = mask << 1; 668 } 669 return (i); 670 } 671 672 static uint16_t 673 overflow_page(HTAB *hashp) 674 { 675 uint32_t *freep = NULL; 676 int max_free, offset, splitnum; 677 uint16_t addr; 678 int bit, first_page, free_bit, free_page, i, in_use_bits, j; 679 #ifdef DEBUG2 680 int tmp1, tmp2; 681 #endif 682 splitnum = hashp->OVFL_POINT; 683 max_free = hashp->SPARES[splitnum]; 684 685 free_page = (uint32_t)(max_free - 1) >> (hashp->BSHIFT + BYTE_SHIFT); 686 free_bit = (max_free - 1) & ((hashp->BSIZE << BYTE_SHIFT) - 1); 687 688 /* Look through all the free maps to find the first free block */ 689 first_page = (uint32_t)hashp->LAST_FREED >>(hashp->BSHIFT + BYTE_SHIFT); 690 for ( i = first_page; i <= free_page; i++ ) { 691 if (!(freep = (uint32_t *)hashp->mapp[i]) && 692 !(freep = fetch_bitmap(hashp, i))) 693 return (0); 694 if (i == free_page) 695 in_use_bits = free_bit; 696 else 697 in_use_bits = (hashp->BSIZE << BYTE_SHIFT) - 1; 698 699 if (i == first_page) { 700 bit = hashp->LAST_FREED & 701 ((hashp->BSIZE << BYTE_SHIFT) - 1); 702 j = bit / BITS_PER_MAP; 703 bit = bit & ~(BITS_PER_MAP - 1); 704 } else { 705 bit = 0; 706 j = 0; 707 } 708 for (; bit <= in_use_bits; j++, bit += BITS_PER_MAP) 709 if (freep[j] != ALL_SET) 710 goto found; 711 } 712 713 /* No Free Page Found */ 714 hashp->LAST_FREED = hashp->SPARES[splitnum]; 715 hashp->SPARES[splitnum]++; 716 offset = hashp->SPARES[splitnum] - 717 (splitnum ? hashp->SPARES[splitnum - 1] : 0); 718 719 #define OVMSG "HASH: Out of overflow pages. Increase page size\n" 720 if (offset > SPLITMASK) { 721 if (++splitnum >= NCACHED) { 722 (void)write(STDERR_FILENO, OVMSG, sizeof(OVMSG) - 1); 723 errno = EFBIG; 724 return (0); 725 } 726 hashp->OVFL_POINT = splitnum; 727 hashp->SPARES[splitnum] = hashp->SPARES[splitnum-1]; 728 hashp->SPARES[splitnum-1]--; 729 offset = 1; 730 } 731 732 /* Check if we need to allocate a new bitmap page */ 733 if (free_bit == (hashp->BSIZE << BYTE_SHIFT) - 1) { 734 free_page++; 735 if (free_page >= NCACHED) { 736 (void)write(STDERR_FILENO, OVMSG, sizeof(OVMSG) - 1); 737 errno = EFBIG; 738 return (0); 739 } 740 /* 741 * This is tricky. The 1 indicates that you want the new page 742 * allocated with 1 clear bit. Actually, you are going to 743 * allocate 2 pages from this map. The first is going to be 744 * the map page, the second is the overflow page we were 745 * looking for. The init_bitmap routine automatically, sets 746 * the first bit of itself to indicate that the bitmap itself 747 * is in use. We would explicitly set the second bit, but 748 * don't have to if we tell init_bitmap not to leave it clear 749 * in the first place. 750 */ 751 if (__ibitmap(hashp, 752 (int)OADDR_OF(splitnum, offset), 1, free_page)) 753 return (0); 754 hashp->SPARES[splitnum]++; 755 #ifdef DEBUG2 756 free_bit = 2; 757 #endif 758 offset++; 759 if (offset > SPLITMASK) { 760 if (++splitnum >= NCACHED) { 761 (void)write(STDERR_FILENO, OVMSG, 762 sizeof(OVMSG) - 1); 763 errno = EFBIG; 764 return (0); 765 } 766 hashp->OVFL_POINT = splitnum; 767 hashp->SPARES[splitnum] = hashp->SPARES[splitnum-1]; 768 hashp->SPARES[splitnum-1]--; 769 offset = 0; 770 } 771 } else { 772 /* 773 * Free_bit addresses the last used bit. Bump it to address 774 * the first available bit. 775 */ 776 free_bit++; 777 SETBIT(freep, free_bit); 778 } 779 780 /* Calculate address of the new overflow page */ 781 addr = OADDR_OF(splitnum, offset); 782 #ifdef DEBUG2 783 (void)fprintf(stderr, "OVERFLOW_PAGE: ADDR: %d BIT: %d PAGE %d\n", 784 addr, free_bit, free_page); 785 #endif 786 return (addr); 787 788 found: 789 bit = bit + first_free(freep[j]); 790 SETBIT(freep, bit); 791 #ifdef DEBUG2 792 tmp1 = bit; 793 tmp2 = i; 794 #endif 795 /* 796 * Bits are addressed starting with 0, but overflow pages are addressed 797 * beginning at 1. Bit is a bit addressnumber, so we need to increment 798 * it to convert it to a page number. 799 */ 800 bit = 1 + bit + (i * (hashp->BSIZE << BYTE_SHIFT)); 801 if (bit >= hashp->LAST_FREED) 802 hashp->LAST_FREED = bit - 1; 803 804 /* Calculate the split number for this page */ 805 for (i = 0; (i < splitnum) && (bit > hashp->SPARES[i]); i++); 806 offset = (i ? bit - hashp->SPARES[i - 1] : bit); 807 if (offset >= SPLITMASK) { 808 (void)write(STDERR_FILENO, OVMSG, sizeof(OVMSG) - 1); 809 errno = EFBIG; 810 return (0); /* Out of overflow pages */ 811 } 812 addr = OADDR_OF(i, offset); 813 #ifdef DEBUG2 814 (void)fprintf(stderr, "OVERFLOW_PAGE: ADDR: %d BIT: %d PAGE %d\n", 815 addr, tmp1, tmp2); 816 #endif 817 818 /* Allocate and return the overflow page */ 819 return (addr); 820 } 821 822 /* 823 * Mark this overflow page as free. 824 */ 825 void 826 __free_ovflpage(HTAB *hashp, BUFHEAD *obufp) 827 { 828 uint16_t addr; 829 uint32_t *freep; 830 int bit_address, free_page, free_bit; 831 uint16_t ndx; 832 833 addr = obufp->addr; 834 #ifdef DEBUG1 835 (void)fprintf(stderr, "Freeing %d\n", addr); 836 #endif 837 ndx = (((uint32_t)addr) >> SPLITSHIFT); 838 bit_address = 839 (ndx ? hashp->SPARES[ndx - 1] : 0) + (addr & SPLITMASK) - 1; 840 if (bit_address < hashp->LAST_FREED) 841 hashp->LAST_FREED = bit_address; 842 free_page = ((uint32_t)bit_address >> (hashp->BSHIFT + BYTE_SHIFT)); 843 free_bit = bit_address & ((hashp->BSIZE << BYTE_SHIFT) - 1); 844 845 if (!(freep = hashp->mapp[free_page])) 846 freep = fetch_bitmap(hashp, free_page); 847 /* 848 * This had better never happen. It means we tried to read a bitmap 849 * that has already had overflow pages allocated off it, and we 850 * failed to read it from the file. 851 */ 852 _DIAGASSERT(freep != NULL); 853 CLRBIT(freep, free_bit); 854 #ifdef DEBUG2 855 (void)fprintf(stderr, "FREE_OVFLPAGE: ADDR: %d BIT: %d PAGE %d\n", 856 obufp->addr, free_bit, free_page); 857 #endif 858 __reclaim_buf(hashp, obufp); 859 } 860 861 /* 862 * Returns: 863 * 0 success 864 * -1 failure 865 */ 866 static int 867 open_temp(HTAB *hashp) 868 { 869 sigset_t set, oset; 870 char *envtmp; 871 char namestr[PATH_MAX]; 872 873 if (issetugid()) 874 envtmp = NULL; 875 else 876 envtmp = getenv("TMPDIR"); 877 878 if (-1 == snprintf(namestr, sizeof(namestr), "%s/_hashXXXXXX", 879 envtmp ? envtmp : _PATH_TMP)) 880 return -1; 881 882 /* Block signals; make sure file goes away at process exit. */ 883 (void)sigfillset(&set); 884 (void)sigprocmask(SIG_BLOCK, &set, &oset); 885 if ((hashp->fp = mkstemp(namestr)) != -1) { 886 (void)unlink(namestr); 887 (void)fcntl(hashp->fp, F_SETFD, FD_CLOEXEC); 888 } 889 (void)sigprocmask(SIG_SETMASK, &oset, (sigset_t *)NULL); 890 return (hashp->fp != -1 ? 0 : -1); 891 } 892 893 /* 894 * We have to know that the key will fit, but the last entry on the page is 895 * an overflow pair, so we need to shift things. 896 */ 897 static void 898 squeeze_key(uint16_t *sp, const DBT *key, const DBT *val) 899 { 900 char *p; 901 uint16_t free_space, n, off, pageno; 902 size_t temp; 903 904 p = (char *)(void *)sp; 905 n = sp[0]; 906 free_space = FREESPACE(sp); 907 off = OFFSET(sp); 908 909 pageno = sp[n - 1]; 910 _DIAGASSERT(off >= key->size); 911 off -= (uint16_t)key->size; 912 sp[n - 1] = off; 913 memmove(p + off, key->data, key->size); 914 _DIAGASSERT(off >= val->size); 915 off -= (uint16_t)val->size; 916 sp[n] = off; 917 memmove(p + off, val->data, val->size); 918 sp[0] = n + 2; 919 sp[n + 1] = pageno; 920 sp[n + 2] = OVFLPAGE; 921 temp = PAIRSIZE(key, val); 922 _DIAGASSERT(free_space >= temp); 923 FREESPACE(sp) = (uint16_t)(free_space - temp); 924 OFFSET(sp) = off; 925 } 926 927 static uint32_t * 928 fetch_bitmap(HTAB *hashp, int ndx) 929 { 930 if (ndx >= hashp->nmaps) 931 return (NULL); 932 if ((hashp->mapp[ndx] = malloc((size_t)hashp->BSIZE)) == NULL) 933 return (NULL); 934 if (__get_page(hashp, 935 (char *)(void *)hashp->mapp[ndx], (uint32_t)hashp->BITMAPS[ndx], 0, 1, 1)) { 936 free(hashp->mapp[ndx]); 937 return (NULL); 938 } 939 return (hashp->mapp[ndx]); 940 } 941 942 #ifdef DEBUG4 943 void print_chain(HTAB *, uint32_t); 944 void 945 print_chain(HTAB *hashp, uint32_t addr) 946 { 947 BUFHEAD *bufp; 948 uint16_t *bp, oaddr; 949 950 (void)fprintf(stderr, "%d ", addr); 951 bufp = __get_buf(hashp, addr, NULL, 0); 952 bp = (uint16_t *)bufp->page; 953 while (bp[0] && ((bp[bp[0]] == OVFLPAGE) || 954 ((bp[0] > 2) && bp[2] < REAL_KEY))) { 955 oaddr = bp[bp[0] - 1]; 956 (void)fprintf(stderr, "%d ", (int)oaddr); 957 bufp = __get_buf(hashp, (uint32_t)oaddr, bufp, 0); 958 bp = (uint16_t *)bufp->page; 959 } 960 (void)fprintf(stderr, "\n"); 961 } 962 #endif 963