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_page.c 8.7 (Berkeley) 8/16/94"; 37 #endif /* LIBC_SCCS and not lint */ 38 #include <sys/cdefs.h> 39 __FBSDID("$FreeBSD$"); 40 41 /* 42 * PACKAGE: hashing 43 * 44 * DESCRIPTION: 45 * Page manipulation for hashing package. 46 * 47 * ROUTINES: 48 * 49 * External 50 * __get_page 51 * __add_ovflpage 52 * Internal 53 * overflow_page 54 * open_temp 55 */ 56 57 #include "namespace.h" 58 #include <sys/param.h> 59 60 #include <errno.h> 61 #include <fcntl.h> 62 #include <signal.h> 63 #include <stdio.h> 64 #include <stdlib.h> 65 #include <string.h> 66 #include <unistd.h> 67 #ifdef DEBUG 68 #include <assert.h> 69 #endif 70 #include "un-namespace.h" 71 #include "libc_private.h" 72 73 #include <db.h> 74 #include "hash.h" 75 #include "page.h" 76 #include "extern.h" 77 78 static u_int32_t *fetch_bitmap(HTAB *, int); 79 static u_int32_t first_free(u_int32_t); 80 static int open_temp(HTAB *); 81 static u_int16_t overflow_page(HTAB *); 82 static void putpair(char *, const DBT *, const DBT *); 83 static void squeeze_key(u_int16_t *, const DBT *, const DBT *); 84 static int ugly_split(HTAB *, u_int32_t, BUFHEAD *, BUFHEAD *, int, int); 85 86 #define PAGE_INIT(P) { \ 87 ((u_int16_t *)(P))[0] = 0; \ 88 ((u_int16_t *)(P))[1] = hashp->BSIZE - 3 * sizeof(u_int16_t); \ 89 ((u_int16_t *)(P))[2] = hashp->BSIZE; \ 90 } 91 92 /* 93 * This is called AFTER we have verified that there is room on the page for 94 * the pair (PAIRFITS has returned true) so we go right ahead and start moving 95 * stuff on. 96 */ 97 static void 98 putpair(char *p, const DBT *key, const DBT *val) 99 { 100 u_int16_t *bp, n, off; 101 102 bp = (u_int16_t *)p; 103 104 /* Enter the key first. */ 105 n = bp[0]; 106 107 off = OFFSET(bp) - key->size; 108 memmove(p + off, key->data, key->size); 109 bp[++n] = off; 110 111 /* Now the data. */ 112 off -= val->size; 113 memmove(p + off, val->data, val->size); 114 bp[++n] = off; 115 116 /* Adjust page info. */ 117 bp[0] = n; 118 bp[n + 1] = off - ((n + 3) * sizeof(u_int16_t)); 119 bp[n + 2] = off; 120 } 121 122 /* 123 * Returns: 124 * 0 OK 125 * -1 error 126 */ 127 int 128 __delpair(HTAB *hashp, BUFHEAD *bufp, int ndx) 129 { 130 u_int16_t *bp, newoff, pairlen; 131 int n; 132 133 bp = (u_int16_t *)bufp->page; 134 n = bp[0]; 135 136 if (bp[ndx + 1] < REAL_KEY) 137 return (__big_delete(hashp, bufp)); 138 if (ndx != 1) 139 newoff = bp[ndx - 1]; 140 else 141 newoff = hashp->BSIZE; 142 pairlen = newoff - bp[ndx + 1]; 143 144 if (ndx != (n - 1)) { 145 /* Hard Case -- need to shuffle keys */ 146 int i; 147 char *src = bufp->page + (int)OFFSET(bp); 148 char *dst = src + (int)pairlen; 149 memmove(dst, src, bp[ndx + 1] - OFFSET(bp)); 150 151 /* Now adjust the pointers */ 152 for (i = ndx + 2; i <= n; i += 2) { 153 if (bp[i + 1] == OVFLPAGE) { 154 bp[i - 2] = bp[i]; 155 bp[i - 1] = bp[i + 1]; 156 } else { 157 bp[i - 2] = bp[i] + pairlen; 158 bp[i - 1] = bp[i + 1] + pairlen; 159 } 160 } 161 if (ndx == hashp->cndx) { 162 /* 163 * We just removed pair we were "pointing" to. 164 * By moving back the cndx we ensure subsequent 165 * hash_seq() calls won't skip over any entries. 166 */ 167 hashp->cndx -= 2; 168 } 169 } 170 /* Finally adjust the page data */ 171 bp[n] = OFFSET(bp) + pairlen; 172 bp[n - 1] = bp[n + 1] + pairlen + 2 * sizeof(u_int16_t); 173 bp[0] = n - 2; 174 hashp->NKEYS--; 175 176 bufp->flags |= BUF_MOD; 177 return (0); 178 } 179 /* 180 * Returns: 181 * 0 ==> OK 182 * -1 ==> Error 183 */ 184 int 185 __split_page(HTAB *hashp, u_int32_t obucket, u_int32_t nbucket) 186 { 187 BUFHEAD *new_bufp, *old_bufp; 188 u_int16_t *ino; 189 char *np; 190 DBT key, val; 191 int n, ndx, retval; 192 u_int16_t copyto, diff, off, moved; 193 char *op; 194 195 copyto = (u_int16_t)hashp->BSIZE; 196 off = (u_int16_t)hashp->BSIZE; 197 old_bufp = __get_buf(hashp, obucket, NULL, 0); 198 if (old_bufp == NULL) 199 return (-1); 200 new_bufp = __get_buf(hashp, nbucket, NULL, 0); 201 if (new_bufp == NULL) 202 return (-1); 203 204 old_bufp->flags |= (BUF_MOD | BUF_PIN); 205 new_bufp->flags |= (BUF_MOD | BUF_PIN); 206 207 ino = (u_int16_t *)(op = old_bufp->page); 208 np = new_bufp->page; 209 210 moved = 0; 211 212 for (n = 1, ndx = 1; n < ino[0]; n += 2) { 213 if (ino[n + 1] < REAL_KEY) { 214 retval = ugly_split(hashp, obucket, old_bufp, new_bufp, 215 (int)copyto, (int)moved); 216 old_bufp->flags &= ~BUF_PIN; 217 new_bufp->flags &= ~BUF_PIN; 218 return (retval); 219 220 } 221 key.data = (u_char *)op + ino[n]; 222 key.size = off - ino[n]; 223 224 if (__call_hash(hashp, key.data, key.size) == obucket) { 225 /* Don't switch page */ 226 diff = copyto - off; 227 if (diff) { 228 copyto = ino[n + 1] + diff; 229 memmove(op + copyto, op + ino[n + 1], 230 off - ino[n + 1]); 231 ino[ndx] = copyto + ino[n] - ino[n + 1]; 232 ino[ndx + 1] = copyto; 233 } else 234 copyto = ino[n + 1]; 235 ndx += 2; 236 } else { 237 /* Switch page */ 238 val.data = (u_char *)op + ino[n + 1]; 239 val.size = ino[n] - ino[n + 1]; 240 putpair(np, &key, &val); 241 moved += 2; 242 } 243 244 off = ino[n + 1]; 245 } 246 247 /* Now clean up the page */ 248 ino[0] -= moved; 249 FREESPACE(ino) = copyto - sizeof(u_int16_t) * (ino[0] + 3); 250 OFFSET(ino) = copyto; 251 252 #ifdef DEBUG3 253 (void)fprintf(stderr, "split %d/%d\n", 254 ((u_int16_t *)np)[0] / 2, 255 ((u_int16_t *)op)[0] / 2); 256 #endif 257 /* unpin both pages */ 258 old_bufp->flags &= ~BUF_PIN; 259 new_bufp->flags &= ~BUF_PIN; 260 return (0); 261 } 262 263 /* 264 * Called when we encounter an overflow or big key/data page during split 265 * handling. This is special cased since we have to begin checking whether 266 * the key/data pairs fit on their respective pages and because we may need 267 * overflow pages for both the old and new pages. 268 * 269 * The first page might be a page with regular key/data pairs in which case 270 * we have a regular overflow condition and just need to go on to the next 271 * page or it might be a big key/data pair in which case we need to fix the 272 * big key/data pair. 273 * 274 * Returns: 275 * 0 ==> success 276 * -1 ==> failure 277 */ 278 static int 279 ugly_split(HTAB *hashp, 280 u_int32_t obucket, /* Same as __split_page. */ 281 BUFHEAD *old_bufp, 282 BUFHEAD *new_bufp, 283 int copyto, /* First byte on page which contains key/data values. */ 284 int moved) /* Number of pairs moved to new page. */ 285 { 286 BUFHEAD *bufp; /* Buffer header for ino */ 287 u_int16_t *ino; /* Page keys come off of */ 288 u_int16_t *np; /* New page */ 289 u_int16_t *op; /* Page keys go on to if they aren't moving */ 290 291 BUFHEAD *last_bfp; /* Last buf header OVFL needing to be freed */ 292 DBT key, val; 293 SPLIT_RETURN ret; 294 u_int16_t n, off, ov_addr, scopyto; 295 char *cino; /* Character value of ino */ 296 297 bufp = old_bufp; 298 ino = (u_int16_t *)old_bufp->page; 299 np = (u_int16_t *)new_bufp->page; 300 op = (u_int16_t *)old_bufp->page; 301 last_bfp = NULL; 302 scopyto = (u_int16_t)copyto; /* ANSI */ 303 304 n = ino[0] - 1; 305 while (n < ino[0]) { 306 if (ino[2] < REAL_KEY && ino[2] != OVFLPAGE) { 307 if (__big_split(hashp, old_bufp, 308 new_bufp, bufp, bufp->addr, obucket, &ret)) 309 return (-1); 310 old_bufp = ret.oldp; 311 if (!old_bufp) 312 return (-1); 313 op = (u_int16_t *)old_bufp->page; 314 new_bufp = ret.newp; 315 if (!new_bufp) 316 return (-1); 317 np = (u_int16_t *)new_bufp->page; 318 bufp = ret.nextp; 319 if (!bufp) 320 return (0); 321 cino = (char *)bufp->page; 322 ino = (u_int16_t *)cino; 323 last_bfp = ret.nextp; 324 } else if (ino[n + 1] == OVFLPAGE) { 325 ov_addr = ino[n]; 326 /* 327 * Fix up the old page -- the extra 2 are the fields 328 * which contained the overflow information. 329 */ 330 ino[0] -= (moved + 2); 331 FREESPACE(ino) = 332 scopyto - sizeof(u_int16_t) * (ino[0] + 3); 333 OFFSET(ino) = scopyto; 334 335 bufp = __get_buf(hashp, ov_addr, bufp, 0); 336 if (!bufp) 337 return (-1); 338 339 ino = (u_int16_t *)bufp->page; 340 n = 1; 341 scopyto = hashp->BSIZE; 342 moved = 0; 343 344 if (last_bfp) 345 __free_ovflpage(hashp, last_bfp); 346 last_bfp = bufp; 347 } 348 /* Move regular sized pairs of there are any */ 349 off = hashp->BSIZE; 350 for (n = 1; (n < ino[0]) && (ino[n + 1] >= REAL_KEY); n += 2) { 351 cino = (char *)ino; 352 key.data = (u_char *)cino + ino[n]; 353 key.size = off - ino[n]; 354 val.data = (u_char *)cino + ino[n + 1]; 355 val.size = ino[n] - ino[n + 1]; 356 off = ino[n + 1]; 357 358 if (__call_hash(hashp, key.data, key.size) == obucket) { 359 /* Keep on old page */ 360 if (PAIRFITS(op, (&key), (&val))) 361 putpair((char *)op, &key, &val); 362 else { 363 old_bufp = 364 __add_ovflpage(hashp, old_bufp); 365 if (!old_bufp) 366 return (-1); 367 op = (u_int16_t *)old_bufp->page; 368 putpair((char *)op, &key, &val); 369 } 370 old_bufp->flags |= BUF_MOD; 371 } else { 372 /* Move to new page */ 373 if (PAIRFITS(np, (&key), (&val))) 374 putpair((char *)np, &key, &val); 375 else { 376 new_bufp = 377 __add_ovflpage(hashp, new_bufp); 378 if (!new_bufp) 379 return (-1); 380 np = (u_int16_t *)new_bufp->page; 381 putpair((char *)np, &key, &val); 382 } 383 new_bufp->flags |= BUF_MOD; 384 } 385 } 386 } 387 if (last_bfp) 388 __free_ovflpage(hashp, last_bfp); 389 return (0); 390 } 391 392 /* 393 * Add the given pair to the page 394 * 395 * Returns: 396 * 0 ==> OK 397 * 1 ==> failure 398 */ 399 int 400 __addel(HTAB *hashp, BUFHEAD *bufp, const DBT *key, const DBT *val) 401 { 402 u_int16_t *bp, *sop; 403 int do_expand; 404 405 bp = (u_int16_t *)bufp->page; 406 do_expand = 0; 407 while (bp[0] && (bp[2] < REAL_KEY || bp[bp[0]] < REAL_KEY)) 408 /* Exception case */ 409 if (bp[2] == FULL_KEY_DATA && bp[0] == 2) 410 /* This is the last page of a big key/data pair 411 and we need to add another page */ 412 break; 413 else if (bp[2] < REAL_KEY && bp[bp[0]] != OVFLPAGE) { 414 bufp = __get_buf(hashp, bp[bp[0] - 1], bufp, 0); 415 if (!bufp) 416 return (-1); 417 bp = (u_int16_t *)bufp->page; 418 } else if (bp[bp[0]] != OVFLPAGE) { 419 /* Short key/data pairs, no more pages */ 420 break; 421 } else { 422 /* Try to squeeze key on this page */ 423 if (bp[2] >= REAL_KEY && 424 FREESPACE(bp) >= PAIRSIZE(key, val)) { 425 squeeze_key(bp, key, val); 426 goto stats; 427 } else { 428 bufp = __get_buf(hashp, bp[bp[0] - 1], bufp, 0); 429 if (!bufp) 430 return (-1); 431 bp = (u_int16_t *)bufp->page; 432 } 433 } 434 435 if (PAIRFITS(bp, key, val)) 436 putpair(bufp->page, key, val); 437 else { 438 do_expand = 1; 439 bufp = __add_ovflpage(hashp, bufp); 440 if (!bufp) 441 return (-1); 442 sop = (u_int16_t *)bufp->page; 443 444 if (PAIRFITS(sop, key, val)) 445 putpair((char *)sop, key, val); 446 else 447 if (__big_insert(hashp, bufp, key, val)) 448 return (-1); 449 } 450 stats: 451 bufp->flags |= BUF_MOD; 452 /* 453 * If the average number of keys per bucket exceeds the fill factor, 454 * expand the table. 455 */ 456 hashp->NKEYS++; 457 if (do_expand || 458 (hashp->NKEYS / (hashp->MAX_BUCKET + 1) > hashp->FFACTOR)) 459 return (__expand_table(hashp)); 460 return (0); 461 } 462 463 /* 464 * 465 * Returns: 466 * pointer on success 467 * NULL on error 468 */ 469 BUFHEAD * 470 __add_ovflpage(HTAB *hashp, BUFHEAD *bufp) 471 { 472 u_int16_t *sp, ndx, ovfl_num; 473 #ifdef DEBUG1 474 int tmp1, tmp2; 475 #endif 476 sp = (u_int16_t *)bufp->page; 477 478 /* Check if we are dynamically determining the fill factor */ 479 if (hashp->FFACTOR == DEF_FFACTOR) { 480 hashp->FFACTOR = sp[0] >> 1; 481 if (hashp->FFACTOR < MIN_FFACTOR) 482 hashp->FFACTOR = MIN_FFACTOR; 483 } 484 bufp->flags |= BUF_MOD; 485 ovfl_num = overflow_page(hashp); 486 #ifdef DEBUG1 487 tmp1 = bufp->addr; 488 tmp2 = bufp->ovfl ? bufp->ovfl->addr : 0; 489 #endif 490 if (!ovfl_num || !(bufp->ovfl = __get_buf(hashp, ovfl_num, bufp, 1))) 491 return (NULL); 492 bufp->ovfl->flags |= BUF_MOD; 493 #ifdef DEBUG1 494 (void)fprintf(stderr, "ADDOVFLPAGE: %d->ovfl was %d is now %d\n", 495 tmp1, tmp2, bufp->ovfl->addr); 496 #endif 497 ndx = sp[0]; 498 /* 499 * Since a pair is allocated on a page only if there's room to add 500 * an overflow page, we know that the OVFL information will fit on 501 * the page. 502 */ 503 sp[ndx + 4] = OFFSET(sp); 504 sp[ndx + 3] = FREESPACE(sp) - OVFLSIZE; 505 sp[ndx + 1] = ovfl_num; 506 sp[ndx + 2] = OVFLPAGE; 507 sp[0] = ndx + 2; 508 #ifdef HASH_STATISTICS 509 hash_overflows++; 510 #endif 511 return (bufp->ovfl); 512 } 513 514 /* 515 * Returns: 516 * 0 indicates SUCCESS 517 * -1 indicates FAILURE 518 */ 519 int 520 __get_page(HTAB *hashp, char *p, u_int32_t bucket, int is_bucket, int is_disk, 521 int is_bitmap) 522 { 523 int fd, page, size, rsize; 524 u_int16_t *bp; 525 526 fd = hashp->fp; 527 size = hashp->BSIZE; 528 529 if ((fd == -1) || !is_disk) { 530 PAGE_INIT(p); 531 return (0); 532 } 533 if (is_bucket) 534 page = BUCKET_TO_PAGE(bucket); 535 else 536 page = OADDR_TO_PAGE(bucket); 537 if ((rsize = pread(fd, p, size, (off_t)page << hashp->BSHIFT)) == -1) 538 return (-1); 539 bp = (u_int16_t *)p; 540 if (!rsize) 541 bp[0] = 0; /* We hit the EOF, so initialize a new page */ 542 else 543 if (rsize != size) { 544 errno = EFTYPE; 545 return (-1); 546 } 547 if (!is_bitmap && !bp[0]) { 548 PAGE_INIT(p); 549 } else 550 if (hashp->LORDER != BYTE_ORDER) { 551 int i, max; 552 553 if (is_bitmap) { 554 max = hashp->BSIZE >> 2; /* divide by 4 */ 555 for (i = 0; i < max; i++) 556 M_32_SWAP(((int *)p)[i]); 557 } else { 558 M_16_SWAP(bp[0]); 559 max = bp[0] + 2; 560 for (i = 1; i <= max; i++) 561 M_16_SWAP(bp[i]); 562 } 563 } 564 return (0); 565 } 566 567 /* 568 * Write page p to disk 569 * 570 * Returns: 571 * 0 ==> OK 572 * -1 ==>failure 573 */ 574 int 575 __put_page(HTAB *hashp, char *p, u_int32_t bucket, int is_bucket, int is_bitmap) 576 { 577 int fd, page, size; 578 ssize_t wsize; 579 char pbuf[MAX_BSIZE]; 580 581 size = hashp->BSIZE; 582 if ((hashp->fp == -1) && open_temp(hashp)) 583 return (-1); 584 fd = hashp->fp; 585 586 if (hashp->LORDER != BYTE_ORDER) { 587 int i, max; 588 589 memcpy(pbuf, p, size); 590 if (is_bitmap) { 591 max = hashp->BSIZE >> 2; /* divide by 4 */ 592 for (i = 0; i < max; i++) 593 M_32_SWAP(((int *)pbuf)[i]); 594 } else { 595 uint16_t *bp = (uint16_t *)(void *)pbuf; 596 max = bp[0] + 2; 597 for (i = 0; i <= max; i++) 598 M_16_SWAP(bp[i]); 599 } 600 p = pbuf; 601 } 602 if (is_bucket) 603 page = BUCKET_TO_PAGE(bucket); 604 else 605 page = OADDR_TO_PAGE(bucket); 606 if ((wsize = pwrite(fd, p, size, (off_t)page << hashp->BSHIFT)) == -1) 607 /* Errno is set */ 608 return (-1); 609 if (wsize != size) { 610 errno = EFTYPE; 611 return (-1); 612 } 613 return (0); 614 } 615 616 #define BYTE_MASK ((1 << INT_BYTE_SHIFT) -1) 617 /* 618 * Initialize a new bitmap page. Bitmap pages are left in memory 619 * once they are read in. 620 */ 621 int 622 __ibitmap(HTAB *hashp, int pnum, int nbits, int ndx) 623 { 624 u_int32_t *ip; 625 int clearbytes, clearints; 626 627 if ((ip = (u_int32_t *)malloc(hashp->BSIZE)) == NULL) 628 return (1); 629 hashp->nmaps++; 630 clearints = ((nbits - 1) >> INT_BYTE_SHIFT) + 1; 631 clearbytes = clearints << INT_TO_BYTE; 632 (void)memset((char *)ip, 0, clearbytes); 633 (void)memset(((char *)ip) + clearbytes, 0xFF, 634 hashp->BSIZE - clearbytes); 635 ip[clearints - 1] = ALL_SET << (nbits & BYTE_MASK); 636 SETBIT(ip, 0); 637 hashp->BITMAPS[ndx] = (u_int16_t)pnum; 638 hashp->mapp[ndx] = ip; 639 return (0); 640 } 641 642 static u_int32_t 643 first_free(u_int32_t map) 644 { 645 u_int32_t i, mask; 646 647 mask = 0x1; 648 for (i = 0; i < BITS_PER_MAP; i++) { 649 if (!(mask & map)) 650 return (i); 651 mask = mask << 1; 652 } 653 return (i); 654 } 655 656 static u_int16_t 657 overflow_page(HTAB *hashp) 658 { 659 u_int32_t *freep; 660 int max_free, offset, splitnum; 661 u_int16_t addr; 662 int bit, first_page, free_bit, free_page, i, in_use_bits, j; 663 #ifdef DEBUG2 664 int tmp1, tmp2; 665 #endif 666 splitnum = hashp->OVFL_POINT; 667 max_free = hashp->SPARES[splitnum]; 668 669 free_page = (max_free - 1) >> (hashp->BSHIFT + BYTE_SHIFT); 670 free_bit = (max_free - 1) & ((hashp->BSIZE << BYTE_SHIFT) - 1); 671 672 /* Look through all the free maps to find the first free block */ 673 first_page = hashp->LAST_FREED >>(hashp->BSHIFT + BYTE_SHIFT); 674 for ( i = first_page; i <= free_page; i++ ) { 675 if (!(freep = (u_int32_t *)hashp->mapp[i]) && 676 !(freep = fetch_bitmap(hashp, i))) 677 return (0); 678 if (i == free_page) 679 in_use_bits = free_bit; 680 else 681 in_use_bits = (hashp->BSIZE << BYTE_SHIFT) - 1; 682 683 if (i == first_page) { 684 bit = hashp->LAST_FREED & 685 ((hashp->BSIZE << BYTE_SHIFT) - 1); 686 j = bit / BITS_PER_MAP; 687 bit = rounddown2(bit, BITS_PER_MAP); 688 } else { 689 bit = 0; 690 j = 0; 691 } 692 for (; bit <= in_use_bits; j++, bit += BITS_PER_MAP) 693 if (freep[j] != ALL_SET) 694 goto found; 695 } 696 697 /* No Free Page Found */ 698 hashp->LAST_FREED = hashp->SPARES[splitnum]; 699 hashp->SPARES[splitnum]++; 700 offset = hashp->SPARES[splitnum] - 701 (splitnum ? hashp->SPARES[splitnum - 1] : 0); 702 703 #define OVMSG "HASH: Out of overflow pages. Increase page size\n" 704 if (offset > SPLITMASK) { 705 if (++splitnum >= NCACHED) { 706 (void)_write(STDERR_FILENO, OVMSG, sizeof(OVMSG) - 1); 707 errno = EFBIG; 708 return (0); 709 } 710 hashp->OVFL_POINT = splitnum; 711 hashp->SPARES[splitnum] = hashp->SPARES[splitnum-1]; 712 hashp->SPARES[splitnum-1]--; 713 offset = 1; 714 } 715 716 /* Check if we need to allocate a new bitmap page */ 717 if (free_bit == (hashp->BSIZE << BYTE_SHIFT) - 1) { 718 free_page++; 719 if (free_page >= NCACHED) { 720 (void)_write(STDERR_FILENO, OVMSG, sizeof(OVMSG) - 1); 721 errno = EFBIG; 722 return (0); 723 } 724 /* 725 * This is tricky. The 1 indicates that you want the new page 726 * allocated with 1 clear bit. Actually, you are going to 727 * allocate 2 pages from this map. The first is going to be 728 * the map page, the second is the overflow page we were 729 * looking for. The init_bitmap routine automatically, sets 730 * the first bit of itself to indicate that the bitmap itself 731 * is in use. We would explicitly set the second bit, but 732 * don't have to if we tell init_bitmap not to leave it clear 733 * in the first place. 734 */ 735 if (__ibitmap(hashp, 736 (int)OADDR_OF(splitnum, offset), 1, free_page)) 737 return (0); 738 hashp->SPARES[splitnum]++; 739 #ifdef DEBUG2 740 free_bit = 2; 741 #endif 742 offset++; 743 if (offset > SPLITMASK) { 744 if (++splitnum >= NCACHED) { 745 (void)_write(STDERR_FILENO, OVMSG, 746 sizeof(OVMSG) - 1); 747 errno = EFBIG; 748 return (0); 749 } 750 hashp->OVFL_POINT = splitnum; 751 hashp->SPARES[splitnum] = hashp->SPARES[splitnum-1]; 752 hashp->SPARES[splitnum-1]--; 753 offset = 0; 754 } 755 } else { 756 /* 757 * Free_bit addresses the last used bit. Bump it to address 758 * the first available bit. 759 */ 760 free_bit++; 761 SETBIT(freep, free_bit); 762 } 763 764 /* Calculate address of the new overflow page */ 765 addr = OADDR_OF(splitnum, offset); 766 #ifdef DEBUG2 767 (void)fprintf(stderr, "OVERFLOW_PAGE: ADDR: %d BIT: %d PAGE %d\n", 768 addr, free_bit, free_page); 769 #endif 770 return (addr); 771 772 found: 773 bit = bit + first_free(freep[j]); 774 SETBIT(freep, bit); 775 #ifdef DEBUG2 776 tmp1 = bit; 777 tmp2 = i; 778 #endif 779 /* 780 * Bits are addressed starting with 0, but overflow pages are addressed 781 * beginning at 1. Bit is a bit addressnumber, so we need to increment 782 * it to convert it to a page number. 783 */ 784 bit = 1 + bit + (i * (hashp->BSIZE << BYTE_SHIFT)); 785 if (bit >= hashp->LAST_FREED) 786 hashp->LAST_FREED = bit - 1; 787 788 /* Calculate the split number for this page */ 789 for (i = 0; (i < splitnum) && (bit > hashp->SPARES[i]); i++); 790 offset = (i ? bit - hashp->SPARES[i - 1] : bit); 791 if (offset >= SPLITMASK) { 792 (void)_write(STDERR_FILENO, OVMSG, sizeof(OVMSG) - 1); 793 errno = EFBIG; 794 return (0); /* Out of overflow pages */ 795 } 796 addr = OADDR_OF(i, offset); 797 #ifdef DEBUG2 798 (void)fprintf(stderr, "OVERFLOW_PAGE: ADDR: %d BIT: %d PAGE %d\n", 799 addr, tmp1, tmp2); 800 #endif 801 802 /* Allocate and return the overflow page */ 803 return (addr); 804 } 805 806 /* 807 * Mark this overflow page as free. 808 */ 809 void 810 __free_ovflpage(HTAB *hashp, BUFHEAD *obufp) 811 { 812 u_int16_t addr; 813 u_int32_t *freep; 814 int bit_address, free_page, free_bit; 815 u_int16_t ndx; 816 817 addr = obufp->addr; 818 #ifdef DEBUG1 819 (void)fprintf(stderr, "Freeing %d\n", addr); 820 #endif 821 ndx = (((u_int16_t)addr) >> SPLITSHIFT); 822 bit_address = 823 (ndx ? hashp->SPARES[ndx - 1] : 0) + (addr & SPLITMASK) - 1; 824 if (bit_address < hashp->LAST_FREED) 825 hashp->LAST_FREED = bit_address; 826 free_page = (bit_address >> (hashp->BSHIFT + BYTE_SHIFT)); 827 free_bit = bit_address & ((hashp->BSIZE << BYTE_SHIFT) - 1); 828 829 if (!(freep = hashp->mapp[free_page])) 830 freep = fetch_bitmap(hashp, free_page); 831 #ifdef DEBUG 832 /* 833 * This had better never happen. It means we tried to read a bitmap 834 * that has already had overflow pages allocated off it, and we 835 * failed to read it from the file. 836 */ 837 if (!freep) 838 assert(0); 839 #endif 840 CLRBIT(freep, free_bit); 841 #ifdef DEBUG2 842 (void)fprintf(stderr, "FREE_OVFLPAGE: ADDR: %d BIT: %d PAGE %d\n", 843 obufp->addr, free_bit, free_page); 844 #endif 845 __reclaim_buf(hashp, obufp); 846 } 847 848 /* 849 * Returns: 850 * 0 success 851 * -1 failure 852 */ 853 static int 854 open_temp(HTAB *hashp) 855 { 856 sigset_t set, oset; 857 int len; 858 char *envtmp; 859 char path[MAXPATHLEN]; 860 861 envtmp = secure_getenv("TMPDIR"); 862 len = snprintf(path, 863 sizeof(path), "%s/_hash.XXXXXX", envtmp ? envtmp : "/tmp"); 864 if (len < 0 || len >= (int)sizeof(path)) { 865 errno = ENAMETOOLONG; 866 return (-1); 867 } 868 869 /* Block signals; make sure file goes away at process exit. */ 870 (void)sigfillset(&set); 871 (void)__libc_sigprocmask(SIG_BLOCK, &set, &oset); 872 if ((hashp->fp = mkostemp(path, O_CLOEXEC)) != -1) 873 (void)unlink(path); 874 (void)__libc_sigprocmask(SIG_SETMASK, &oset, (sigset_t *)NULL); 875 return (hashp->fp != -1 ? 0 : -1); 876 } 877 878 /* 879 * We have to know that the key will fit, but the last entry on the page is 880 * an overflow pair, so we need to shift things. 881 */ 882 static void 883 squeeze_key(u_int16_t *sp, const DBT *key, const DBT *val) 884 { 885 char *p; 886 u_int16_t free_space, n, off, pageno; 887 888 p = (char *)sp; 889 n = sp[0]; 890 free_space = FREESPACE(sp); 891 off = OFFSET(sp); 892 893 pageno = sp[n - 1]; 894 off -= key->size; 895 sp[n - 1] = off; 896 memmove(p + off, key->data, key->size); 897 off -= val->size; 898 sp[n] = off; 899 memmove(p + off, val->data, val->size); 900 sp[0] = n + 2; 901 sp[n + 1] = pageno; 902 sp[n + 2] = OVFLPAGE; 903 FREESPACE(sp) = free_space - PAIRSIZE(key, val); 904 OFFSET(sp) = off; 905 } 906 907 static u_int32_t * 908 fetch_bitmap(HTAB *hashp, int ndx) 909 { 910 if (ndx >= hashp->nmaps) 911 return (NULL); 912 if ((hashp->mapp[ndx] = (u_int32_t *)malloc(hashp->BSIZE)) == NULL) 913 return (NULL); 914 if (__get_page(hashp, 915 (char *)hashp->mapp[ndx], hashp->BITMAPS[ndx], 0, 1, 1)) { 916 free(hashp->mapp[ndx]); 917 return (NULL); 918 } 919 return (hashp->mapp[ndx]); 920 } 921 922 #ifdef DEBUG4 923 int 924 print_chain(int addr) 925 { 926 BUFHEAD *bufp; 927 short *bp, oaddr; 928 929 (void)fprintf(stderr, "%d ", addr); 930 bufp = __get_buf(hashp, addr, NULL, 0); 931 bp = (short *)bufp->page; 932 while (bp[0] && ((bp[bp[0]] == OVFLPAGE) || 933 ((bp[0] > 2) && bp[2] < REAL_KEY))) { 934 oaddr = bp[bp[0] - 1]; 935 (void)fprintf(stderr, "%d ", (int)oaddr); 936 bufp = __get_buf(hashp, (int)oaddr, bufp, 0); 937 bp = (short *)bufp->page; 938 } 939 (void)fprintf(stderr, "\n"); 940 } 941 #endif 942