1 /* $NetBSD: walk.c,v 1.24 2008/12/28 21:51:46 christos Exp $ */ 2 3 /* 4 * SPDX-License-Identifier: BSD-4-Clause 5 * 6 * Copyright (c) 2001 Wasabi Systems, Inc. 7 * All rights reserved. 8 * 9 * Written by Luke Mewburn for Wasabi Systems, Inc. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. All advertising materials mentioning features or use of this software 20 * must display the following acknowledgement: 21 * This product includes software developed for the NetBSD Project by 22 * Wasabi Systems, Inc. 23 * 4. The name of Wasabi Systems, Inc. may not be used to endorse 24 * or promote products derived from this software without specific prior 25 * written permission. 26 * 27 * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND 28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 29 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 30 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL WASABI SYSTEMS, INC 31 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 32 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 33 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 34 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 35 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 36 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 37 * POSSIBILITY OF SUCH DAMAGE. 38 */ 39 40 41 #include <sys/cdefs.h> 42 #include <sys/param.h> 43 #include <sys/stat.h> 44 #include <sys/time.h> 45 46 #include <assert.h> 47 #include <errno.h> 48 #include <fcntl.h> 49 #include <stdio.h> 50 #include <dirent.h> 51 #include <stdlib.h> 52 #include <string.h> 53 #include <unistd.h> 54 55 #include "makefs.h" 56 #include "mtree.h" 57 #include "extern.h" 58 59 static void apply_specdir(const char *, NODE *, fsnode *, int); 60 static void apply_specentry(const char *, NODE *, fsnode *); 61 static fsnode *create_fsnode(const char *, const char *, const char *, 62 struct stat *); 63 64 65 /* 66 * walk_dir -- 67 * build a tree of fsnodes from `root' and `dir', with a parent 68 * fsnode of `parent' (which may be NULL for the root of the tree). 69 * append the tree to a fsnode of `join' if it is not NULL. 70 * each "level" is a directory, with the "." entry guaranteed to be 71 * at the start of the list, and without ".." entries. 72 */ 73 fsnode * 74 walk_dir(const char *root, const char *dir, fsnode *parent, fsnode *join) 75 { 76 fsnode *first, *cur, *prev, *last; 77 DIR *dirp; 78 struct dirent *dent; 79 char path[MAXPATHLEN + 1]; 80 struct stat stbuf; 81 char *name, *rp; 82 size_t len; 83 int dot; 84 85 assert(root != NULL); 86 assert(dir != NULL); 87 88 len = snprintf(path, sizeof(path), "%s/%s", root, dir); 89 if (len >= sizeof(path)) 90 errx(1, "Pathname too long."); 91 if (debug & DEBUG_WALK_DIR) 92 printf("walk_dir: %s %p\n", path, parent); 93 if ((dirp = opendir(path)) == NULL) 94 err(1, "Can't opendir `%s'", path); 95 rp = path + strlen(root) + 1; 96 if (join != NULL) { 97 first = cur = join; 98 while (cur->next != NULL) 99 cur = cur->next; 100 prev = cur; 101 } else 102 first = prev = NULL; 103 last = prev; 104 while ((dent = readdir(dirp)) != NULL) { 105 name = dent->d_name; 106 dot = 0; 107 if (name[0] == '.') 108 switch (name[1]) { 109 case '\0': /* "." */ 110 if (join != NULL) 111 continue; 112 dot = 1; 113 break; 114 case '.': /* ".." */ 115 if (name[2] == '\0') 116 continue; 117 /* FALLTHROUGH */ 118 default: 119 dot = 0; 120 } 121 if (debug & DEBUG_WALK_DIR_NODE) 122 printf("scanning %s/%s/%s\n", root, dir, name); 123 if ((size_t)snprintf(path + len, sizeof(path) - len, "/%s", 124 name) >= sizeof(path) - len) 125 errx(1, "Pathname too long."); 126 if (lstat(path, &stbuf) == -1) 127 err(1, "Can't lstat `%s'", path); 128 #ifdef S_ISSOCK 129 if (S_ISSOCK(stbuf.st_mode & S_IFMT)) { 130 if (debug & DEBUG_WALK_DIR_NODE) 131 printf(" skipping socket %s\n", path); 132 continue; 133 } 134 #endif 135 136 if (join != NULL) { 137 cur = join->next; 138 for (;;) { 139 if (cur == NULL || strcmp(cur->name, name) == 0) 140 break; 141 if (cur == last) { 142 cur = NULL; 143 break; 144 } 145 cur = cur->next; 146 } 147 if (cur != NULL) { 148 if (S_ISDIR(cur->type) && 149 S_ISDIR(stbuf.st_mode)) { 150 if (debug & DEBUG_WALK_DIR_NODE) 151 printf("merging %s with %p\n", 152 path, cur->child); 153 cur->child = walk_dir(root, rp, cur, 154 cur->child); 155 continue; 156 } 157 errx(1, "Can't merge %s `%s' with existing %s", 158 inode_type(stbuf.st_mode), path, 159 inode_type(cur->type)); 160 } 161 } 162 163 cur = create_fsnode(root, dir, name, &stbuf); 164 cur->parent = parent; 165 if (dot) { 166 /* ensure "." is at the start of the list */ 167 cur->next = first; 168 first = cur; 169 if (! prev) 170 prev = cur; 171 cur->first = first; 172 } else { /* not "." */ 173 if (prev) 174 prev->next = cur; 175 prev = cur; 176 if (!first) 177 first = cur; 178 cur->first = first; 179 if (S_ISDIR(cur->type)) { 180 cur->child = walk_dir(root, rp, cur, NULL); 181 continue; 182 } 183 } 184 if (stbuf.st_nlink > 1) { 185 fsinode *curino; 186 187 curino = link_check(cur->inode); 188 if (curino != NULL) { 189 free(cur->inode); 190 cur->inode = curino; 191 cur->inode->nlink++; 192 if (debug & DEBUG_WALK_DIR_LINKCHECK) 193 printf("link_check: found [%llu, %llu]\n", 194 (unsigned long long)curino->st.st_dev, 195 (unsigned long long)curino->st.st_ino); 196 } 197 } 198 if (S_ISLNK(cur->type)) { 199 char slink[PATH_MAX+1]; 200 int llen; 201 202 llen = readlink(path, slink, sizeof(slink) - 1); 203 if (llen == -1) 204 err(1, "Readlink `%s'", path); 205 slink[llen] = '\0'; 206 cur->symlink = estrdup(slink); 207 } 208 } 209 assert(first != NULL); 210 if (join == NULL) 211 for (cur = first->next; cur != NULL; cur = cur->next) 212 cur->first = first; 213 if (closedir(dirp) == -1) 214 err(1, "Can't closedir `%s/%s'", root, dir); 215 return (first); 216 } 217 218 static fsnode * 219 create_fsnode(const char *root, const char *path, const char *name, 220 struct stat *stbuf) 221 { 222 fsnode *cur; 223 224 cur = ecalloc(1, sizeof(*cur)); 225 cur->path = estrdup(path); 226 cur->name = estrdup(name); 227 cur->inode = ecalloc(1, sizeof(*cur->inode)); 228 cur->root = root; 229 cur->type = stbuf->st_mode & S_IFMT; 230 cur->inode->nlink = 1; 231 cur->inode->st = *stbuf; 232 if (stampst.st_ino) { 233 cur->inode->st.st_atime = stampst.st_atime; 234 cur->inode->st.st_mtime = stampst.st_mtime; 235 cur->inode->st.st_ctime = stampst.st_ctime; 236 #if HAVE_STRUCT_STAT_ST_MTIMENSEC 237 cur->inode->st.st_atimensec = stampst.st_atimensec; 238 cur->inode->st.st_mtimensec = stampst.st_mtimensec; 239 cur->inode->st.st_ctimensec = stampst.st_ctimensec; 240 #endif 241 #if HAVE_STRUCT_STAT_BIRTHTIME 242 cur->inode->st.st_birthtime = stampst.st_birthtime; 243 cur->inode->st.st_birthtimensec = stampst.st_birthtimensec; 244 #endif 245 } 246 return (cur); 247 } 248 249 /* 250 * free_fsnodes -- 251 * Removes node from tree and frees it and all of 252 * its descendants. 253 */ 254 void 255 free_fsnodes(fsnode *node) 256 { 257 fsnode *cur, *next; 258 259 assert(node != NULL); 260 261 /* for ".", start with actual parent node */ 262 if (node->first == node) { 263 assert(node->name[0] == '.' && node->name[1] == '\0'); 264 if (node->parent) { 265 assert(node->parent->child == node); 266 node = node->parent; 267 } 268 } 269 270 /* Find ourselves in our sibling list and unlink */ 271 if (node->first != node) { 272 for (cur = node->first; cur->next; cur = cur->next) { 273 if (cur->next == node) { 274 cur->next = node->next; 275 node->next = NULL; 276 break; 277 } 278 } 279 } 280 281 for (cur = node; cur != NULL; cur = next) { 282 next = cur->next; 283 if (cur->child) { 284 cur->child->parent = NULL; 285 free_fsnodes(cur->child); 286 } 287 if (cur->inode->nlink-- == 1) 288 free(cur->inode); 289 if (cur->symlink) 290 free(cur->symlink); 291 free(cur->path); 292 free(cur->name); 293 free(cur); 294 } 295 } 296 297 /* 298 * apply_specfile -- 299 * read in the mtree(8) specfile, and apply it to the tree 300 * at dir,parent. parameters in parent on equivalent types 301 * will be changed to those found in specfile, and missing 302 * entries will be added. 303 */ 304 void 305 apply_specfile(const char *specfile, const char *dir, fsnode *parent, int speconly) 306 { 307 struct timeval start; 308 FILE *fp; 309 NODE *root; 310 311 assert(specfile != NULL); 312 assert(parent != NULL); 313 314 if (debug & DEBUG_APPLY_SPECFILE) 315 printf("apply_specfile: %s, %s %p\n", specfile, dir, parent); 316 317 /* read in the specfile */ 318 if ((fp = fopen(specfile, "r")) == NULL) 319 err(1, "Can't open `%s'", specfile); 320 TIMER_START(start); 321 root = spec(fp); 322 TIMER_RESULTS(start, "spec"); 323 if (fclose(fp) == EOF) 324 err(1, "Can't close `%s'", specfile); 325 326 /* perform some sanity checks */ 327 if (root == NULL) 328 errx(1, "Specfile `%s' did not contain a tree", specfile); 329 assert(strcmp(root->name, ".") == 0); 330 assert(root->type == F_DIR); 331 332 /* merge in the changes */ 333 apply_specdir(dir, root, parent, speconly); 334 335 free_nodes(root); 336 } 337 338 static void 339 apply_specdir(const char *dir, NODE *specnode, fsnode *dirnode, int speconly) 340 { 341 char path[MAXPATHLEN + 1]; 342 NODE *curnode; 343 fsnode *curfsnode; 344 345 assert(specnode != NULL); 346 assert(dirnode != NULL); 347 348 if (debug & DEBUG_APPLY_SPECFILE) 349 printf("apply_specdir: %s %p %p\n", dir, specnode, dirnode); 350 351 if (specnode->type != F_DIR) 352 errx(1, "Specfile node `%s/%s' is not a directory", 353 dir, specnode->name); 354 if (dirnode->type != S_IFDIR) 355 errx(1, "Directory node `%s/%s' is not a directory", 356 dir, dirnode->name); 357 358 apply_specentry(dir, specnode, dirnode); 359 360 /* Remove any filesystem nodes not found in specfile */ 361 /* XXX inefficient. This is O^2 in each dir and it would 362 * have been better never to have walked this part of the tree 363 * to begin with 364 */ 365 if (speconly) { 366 fsnode *next; 367 assert(dirnode->name[0] == '.' && dirnode->name[1] == '\0'); 368 for (curfsnode = dirnode->next; curfsnode != NULL; curfsnode = next) { 369 next = curfsnode->next; 370 for (curnode = specnode->child; curnode != NULL; 371 curnode = curnode->next) { 372 if (strcmp(curnode->name, curfsnode->name) == 0) 373 break; 374 } 375 if (curnode == NULL) { 376 if (debug & DEBUG_APPLY_SPECONLY) { 377 printf("apply_specdir: trimming %s/%s %p\n", dir, curfsnode->name, curfsnode); 378 } 379 free_fsnodes(curfsnode); 380 } 381 } 382 } 383 384 /* now walk specnode->child matching up with dirnode */ 385 for (curnode = specnode->child; curnode != NULL; 386 curnode = curnode->next) { 387 if (debug & DEBUG_APPLY_SPECENTRY) 388 printf("apply_specdir: spec %s\n", 389 curnode->name); 390 for (curfsnode = dirnode->next; curfsnode != NULL; 391 curfsnode = curfsnode->next) { 392 #if 0 /* too verbose for now */ 393 if (debug & DEBUG_APPLY_SPECENTRY) 394 printf("apply_specdir: dirent %s\n", 395 curfsnode->name); 396 #endif 397 if (strcmp(curnode->name, curfsnode->name) == 0) 398 break; 399 } 400 if ((size_t)snprintf(path, sizeof(path), "%s/%s", dir, 401 curnode->name) >= sizeof(path)) 402 errx(1, "Pathname too long."); 403 if (curfsnode == NULL) { /* need new entry */ 404 struct stat stbuf; 405 406 /* 407 * don't add optional spec entries 408 * that lack an existing fs entry 409 */ 410 if ((curnode->flags & F_OPT) && 411 lstat(path, &stbuf) == -1) 412 continue; 413 414 /* check that enough info is provided */ 415 #define NODETEST(t, m) \ 416 if (!(t)) \ 417 errx(1, "`%s': %s not provided", path, m) 418 NODETEST(curnode->flags & F_TYPE, "type"); 419 NODETEST(curnode->flags & F_MODE, "mode"); 420 /* XXX: require F_TIME ? */ 421 NODETEST(curnode->flags & F_GID || 422 curnode->flags & F_GNAME, "group"); 423 NODETEST(curnode->flags & F_UID || 424 curnode->flags & F_UNAME, "user"); 425 /* if (curnode->type == F_BLOCK || curnode->type == F_CHAR) 426 NODETEST(curnode->flags & F_DEV, 427 "device number");*/ 428 #undef NODETEST 429 430 if (debug & DEBUG_APPLY_SPECFILE) 431 printf("apply_specdir: adding %s\n", 432 curnode->name); 433 /* build minimal fsnode */ 434 memset(&stbuf, 0, sizeof(stbuf)); 435 stbuf.st_mode = nodetoino(curnode->type); 436 stbuf.st_nlink = 1; 437 stbuf.st_mtime = stbuf.st_atime = 438 stbuf.st_ctime = start_time.tv_sec; 439 #if HAVE_STRUCT_STAT_ST_MTIMENSEC 440 stbuf.st_mtimensec = stbuf.st_atimensec = 441 stbuf.st_ctimensec = start_time.tv_nsec; 442 #endif 443 curfsnode = create_fsnode(".", ".", curnode->name, 444 &stbuf); 445 curfsnode->parent = dirnode->parent; 446 curfsnode->first = dirnode; 447 curfsnode->next = dirnode->next; 448 dirnode->next = curfsnode; 449 if (curfsnode->type == S_IFDIR) { 450 /* for dirs, make "." entry as well */ 451 curfsnode->child = create_fsnode(".", ".", ".", 452 &stbuf); 453 curfsnode->child->parent = curfsnode; 454 curfsnode->child->first = curfsnode->child; 455 } 456 if (curfsnode->type == S_IFLNK) { 457 assert(curnode->slink != NULL); 458 /* for symlinks, copy the target */ 459 curfsnode->symlink = estrdup(curnode->slink); 460 } 461 } 462 apply_specentry(dir, curnode, curfsnode); 463 if (curnode->type == F_DIR) { 464 if (curfsnode->type != S_IFDIR) 465 errx(1, "`%s' is not a directory", path); 466 assert (curfsnode->child != NULL); 467 apply_specdir(path, curnode, curfsnode->child, speconly); 468 } 469 } 470 } 471 472 static void 473 apply_specentry(const char *dir, NODE *specnode, fsnode *dirnode) 474 { 475 476 assert(specnode != NULL); 477 assert(dirnode != NULL); 478 479 if (nodetoino(specnode->type) != dirnode->type) 480 errx(1, "`%s/%s' type mismatch: specfile %s, tree %s", 481 dir, specnode->name, inode_type(nodetoino(specnode->type)), 482 inode_type(dirnode->type)); 483 484 if (debug & DEBUG_APPLY_SPECENTRY) 485 printf("apply_specentry: %s/%s\n", dir, dirnode->name); 486 487 #define ASEPRINT(t, b, o, n) \ 488 if (debug & DEBUG_APPLY_SPECENTRY) \ 489 printf("\t\t\tchanging %s from " b " to " b "\n", \ 490 t, o, n) 491 492 if (specnode->flags & (F_GID | F_GNAME)) { 493 ASEPRINT("gid", "%d", 494 dirnode->inode->st.st_gid, specnode->st_gid); 495 dirnode->inode->st.st_gid = specnode->st_gid; 496 } 497 if (specnode->flags & F_MODE) { 498 ASEPRINT("mode", "%#o", 499 dirnode->inode->st.st_mode & ALLPERMS, specnode->st_mode); 500 dirnode->inode->st.st_mode &= ~ALLPERMS; 501 dirnode->inode->st.st_mode |= (specnode->st_mode & ALLPERMS); 502 } 503 /* XXX: ignoring F_NLINK for now */ 504 if (specnode->flags & F_SIZE) { 505 ASEPRINT("size", "%lld", 506 (long long)dirnode->inode->st.st_size, 507 (long long)specnode->st_size); 508 dirnode->inode->st.st_size = specnode->st_size; 509 } 510 if (specnode->flags & F_SLINK) { 511 assert(dirnode->symlink != NULL); 512 assert(specnode->slink != NULL); 513 ASEPRINT("symlink", "%s", dirnode->symlink, specnode->slink); 514 free(dirnode->symlink); 515 dirnode->symlink = estrdup(specnode->slink); 516 } 517 if (specnode->flags & F_TIME) { 518 ASEPRINT("time", "%ld", 519 (long)dirnode->inode->st.st_mtime, 520 (long)specnode->st_mtimespec.tv_sec); 521 dirnode->inode->st.st_mtime = specnode->st_mtimespec.tv_sec; 522 dirnode->inode->st.st_atime = specnode->st_mtimespec.tv_sec; 523 dirnode->inode->st.st_ctime = start_time.tv_sec; 524 #if HAVE_STRUCT_STAT_ST_MTIMENSEC 525 dirnode->inode->st.st_mtimensec = specnode->st_mtimespec.tv_nsec; 526 dirnode->inode->st.st_atimensec = specnode->st_mtimespec.tv_nsec; 527 dirnode->inode->st.st_ctimensec = start_time.tv_nsec; 528 #endif 529 } 530 if (specnode->flags & (F_UID | F_UNAME)) { 531 ASEPRINT("uid", "%d", 532 dirnode->inode->st.st_uid, specnode->st_uid); 533 dirnode->inode->st.st_uid = specnode->st_uid; 534 } 535 #if HAVE_STRUCT_STAT_ST_FLAGS 536 if (specnode->flags & F_FLAGS) { 537 ASEPRINT("flags", "%#lX", 538 (unsigned long)dirnode->inode->st.st_flags, 539 (unsigned long)specnode->st_flags); 540 dirnode->inode->st.st_flags = specnode->st_flags; 541 } 542 #endif 543 /* if (specnode->flags & F_DEV) { 544 ASEPRINT("rdev", "%#llx", 545 (unsigned long long)dirnode->inode->st.st_rdev, 546 (unsigned long long)specnode->st_rdev); 547 dirnode->inode->st.st_rdev = specnode->st_rdev; 548 }*/ 549 #undef ASEPRINT 550 551 dirnode->flags |= FSNODE_F_HASSPEC; 552 } 553 554 555 /* 556 * dump_fsnodes -- 557 * dump the fsnodes from `cur' 558 */ 559 void 560 dump_fsnodes(fsnode *root) 561 { 562 fsnode *cur; 563 char path[MAXPATHLEN + 1]; 564 565 printf("dump_fsnodes: %s %p\n", root->path, root); 566 for (cur = root; cur != NULL; cur = cur->next) { 567 if (snprintf(path, sizeof(path), "%s/%s", cur->path, 568 cur->name) >= (int)sizeof(path)) 569 errx(1, "Pathname too long."); 570 571 if (debug & DEBUG_DUMP_FSNODES_VERBOSE) 572 printf("cur=%8p parent=%8p first=%8p ", 573 cur, cur->parent, cur->first); 574 printf("%7s: %s", inode_type(cur->type), path); 575 if (S_ISLNK(cur->type)) { 576 assert(cur->symlink != NULL); 577 printf(" -> %s", cur->symlink); 578 } else { 579 assert (cur->symlink == NULL); 580 } 581 if (cur->inode->nlink > 1) 582 printf(", nlinks=%d", cur->inode->nlink); 583 putchar('\n'); 584 585 if (cur->child) { 586 assert (cur->type == S_IFDIR); 587 dump_fsnodes(cur->child); 588 } 589 } 590 printf("dump_fsnodes: finished %s/%s\n", root->path, root->name); 591 } 592 593 594 /* 595 * inode_type -- 596 * for a given inode type `mode', return a descriptive string. 597 * for most cases, uses inotype() from mtree/misc.c 598 */ 599 const char * 600 inode_type(mode_t mode) 601 { 602 if (S_ISREG(mode)) 603 return ("file"); 604 if (S_ISLNK(mode)) 605 return ("symlink"); 606 if (S_ISDIR(mode)) 607 return ("dir"); 608 if (S_ISLNK(mode)) 609 return ("link"); 610 if (S_ISFIFO(mode)) 611 return ("fifo"); 612 if (S_ISSOCK(mode)) 613 return ("socket"); 614 /* XXX should not happen but handle them */ 615 if (S_ISCHR(mode)) 616 return ("char"); 617 if (S_ISBLK(mode)) 618 return ("block"); 619 return ("unknown"); 620 } 621 622 623 /* 624 * link_check -- 625 * return pointer to fsinode matching `entry's st_ino & st_dev if it exists, 626 * otherwise add `entry' to table and return NULL 627 */ 628 /* This was borrowed from du.c and tweaked to keep an fsnode 629 * pointer instead. -- dbj@netbsd.org 630 */ 631 fsinode * 632 link_check(fsinode *entry) 633 { 634 static struct entry { 635 fsinode *data; 636 } *htable; 637 static int htshift; /* log(allocated size) */ 638 static int htmask; /* allocated size - 1 */ 639 static int htused; /* 2*number of insertions */ 640 int h, h2; 641 uint64_t tmp; 642 /* this constant is (1<<64)/((1+sqrt(5))/2) 643 * aka (word size)/(golden ratio) 644 */ 645 const uint64_t HTCONST = 11400714819323198485ULL; 646 const int HTBITS = 64; 647 648 /* Never store zero in hashtable */ 649 assert(entry); 650 651 /* Extend hash table if necessary, keep load under 0.5 */ 652 if (htused<<1 >= htmask) { 653 struct entry *ohtable; 654 655 if (!htable) 656 htshift = 10; /* starting hashtable size */ 657 else 658 htshift++; /* exponential hashtable growth */ 659 660 htmask = (1 << htshift) - 1; 661 htused = 0; 662 663 ohtable = htable; 664 htable = ecalloc(htmask+1, sizeof(*htable)); 665 /* populate newly allocated hashtable */ 666 if (ohtable) { 667 int i; 668 for (i = 0; i <= htmask>>1; i++) 669 if (ohtable[i].data) 670 link_check(ohtable[i].data); 671 free(ohtable); 672 } 673 } 674 675 /* multiplicative hashing */ 676 tmp = entry->st.st_dev; 677 tmp <<= HTBITS>>1; 678 tmp |= entry->st.st_ino; 679 tmp *= HTCONST; 680 h = tmp >> (HTBITS - htshift); 681 h2 = 1 | ( tmp >> (HTBITS - (htshift<<1) - 1)); /* must be odd */ 682 683 /* open address hashtable search with double hash probing */ 684 while (htable[h].data) { 685 if ((htable[h].data->st.st_ino == entry->st.st_ino) && 686 (htable[h].data->st.st_dev == entry->st.st_dev)) { 687 return htable[h].data; 688 } 689 h = (h + h2) & htmask; 690 } 691 692 /* Insert the current entry into hashtable */ 693 htable[h].data = entry; 694 htused++; 695 return NULL; 696 } 697