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 #include <sys/param.h>
41 #include <sys/stat.h>
42 #include <sys/time.h>
43
44 #include <assert.h>
45 #include <errno.h>
46 #include <fcntl.h>
47 #include <stdio.h>
48 #include <dirent.h>
49 #include <stdlib.h>
50 #include <string.h>
51 #include <unistd.h>
52
53 #include "makefs.h"
54 #include "mtree.h"
55 #include "extern.h"
56
57 static void apply_specdir(const char *, NODE *, fsnode *, int);
58 static void apply_specentry(const char *, NODE *, fsnode *);
59 static fsnode *create_fsnode(const char *, const char *, const char *,
60 struct stat *);
61
62 static int
cmp(const void * _a,const void * _b)63 cmp(const void *_a, const void *_b)
64 {
65 const fsnode * const *a = _a;
66 const fsnode * const *b = _b;
67
68 assert(strcmp((*a)->name, (*b)->name) != 0);
69 if (strcmp((*a)->name, ".") == 0)
70 return (-1);
71 if (strcmp((*b)->name, ".") == 0)
72 return (1);
73 return (strcoll((*a)->name, (*b)->name));
74 }
75
76 /*
77 * Sort the entries rather than relying on the order given by readdir(3),
78 * which might not be reproducible.
79 */
80 static fsnode *
sort_dir(fsnode * list)81 sort_dir(fsnode *list)
82 {
83 fsnode **array;
84 fsnode *cur;
85 size_t nitems, i;
86
87 nitems = 0;
88 for (cur = list; cur != NULL; cur = cur->next)
89 nitems++;
90 assert(nitems > 0);
91
92 array = malloc(nitems * sizeof(fsnode *));
93 if (array == NULL)
94 err(1, "malloc");
95 for (i = 0, cur = list; cur != NULL; i++, cur = cur->next)
96 array[i] = cur;
97 qsort(array, nitems, sizeof(fsnode *), cmp);
98 for (i = 0; i < nitems; i++) {
99 array[i]->first = array[0];
100 array[i]->next = i == nitems - 1 ? NULL : array[i + 1];
101 }
102 cur = array[0];
103 free(array);
104 return (cur);
105 }
106
107 /*
108 * walk_dir --
109 * build a tree of fsnodes from `root' and `dir', with a parent
110 * fsnode of `parent' (which may be NULL for the root of the tree).
111 * append the tree to a fsnode of `join' if it is not NULL.
112 * each "level" is a directory, with the "." entry guaranteed to be
113 * at the start of the list, and without ".." entries.
114 */
115 fsnode *
walk_dir(const char * root,const char * dir,fsnode * parent,fsnode * join)116 walk_dir(const char *root, const char *dir, fsnode *parent, fsnode *join)
117 {
118 fsnode *first, *cur;
119 DIR *dirp;
120 struct dirent *dent;
121 char path[MAXPATHLEN + 1];
122 struct stat stbuf;
123 char *name, *rp;
124 size_t len;
125 int dot;
126
127 assert(root != NULL);
128 assert(dir != NULL);
129
130 len = snprintf(path, sizeof(path), "%s/%s", root, dir);
131 if (len >= sizeof(path))
132 errx(1, "Pathname too long.");
133 if (debug & DEBUG_WALK_DIR)
134 printf("walk_dir: %s %p\n", path, parent);
135 if ((dirp = opendir(path)) == NULL)
136 err(1, "Can't opendir `%s'", path);
137 rp = path + strlen(root) + 1;
138 if (join != NULL) {
139 first = cur = join;
140 while (cur->next != NULL)
141 cur = cur->next;
142 } else
143 first = NULL;
144 while ((dent = readdir(dirp)) != NULL) {
145 name = dent->d_name;
146 dot = 0;
147 if (name[0] == '.')
148 switch (name[1]) {
149 case '\0': /* "." */
150 if (join != NULL)
151 continue;
152 dot = 1;
153 break;
154 case '.': /* ".." */
155 if (name[2] == '\0')
156 continue;
157 /* FALLTHROUGH */
158 default:
159 dot = 0;
160 }
161 if (debug & DEBUG_WALK_DIR_NODE)
162 printf("scanning %s/%s/%s\n", root, dir, name);
163 if ((size_t)snprintf(path + len, sizeof(path) - len, "/%s",
164 name) >= sizeof(path) - len)
165 errx(1, "Pathname too long.");
166 if (lstat(path, &stbuf) == -1)
167 err(1, "Can't lstat `%s'", path);
168 #ifdef S_ISSOCK
169 if (S_ISSOCK(stbuf.st_mode & S_IFMT)) {
170 if (debug & DEBUG_WALK_DIR_NODE)
171 printf(" skipping socket %s\n", path);
172 continue;
173 }
174 #endif
175
176 if (join != NULL) {
177 cur = join->next;
178 for (;;) {
179 if (cur == NULL || strcmp(cur->name, name) == 0)
180 break;
181 cur = cur->next;
182 }
183 if (cur != NULL) {
184 if (S_ISDIR(cur->type) &&
185 S_ISDIR(stbuf.st_mode)) {
186 if (debug & DEBUG_WALK_DIR_NODE)
187 printf("merging %s with %p\n",
188 path, cur->child);
189 cur->child = walk_dir(root, rp, cur,
190 cur->child);
191 continue;
192 }
193 errx(1, "Can't merge %s `%s' with existing %s",
194 inode_type(stbuf.st_mode), path,
195 inode_type(cur->type));
196 }
197 }
198
199 cur = create_fsnode(root, dir, name, &stbuf);
200 cur->parent = parent;
201 cur->next = first;
202 first = cur;
203 if (!dot && S_ISDIR(cur->type)) {
204 cur->child = walk_dir(root, rp, cur, NULL);
205 continue;
206 }
207 if (stbuf.st_nlink > 1) {
208 fsinode *curino;
209
210 curino = link_check(cur->inode);
211 if (curino != NULL) {
212 free(cur->inode);
213 cur->inode = curino;
214 cur->inode->nlink++;
215 if (debug & DEBUG_WALK_DIR_LINKCHECK)
216 printf("link_check: found [%llu, %llu]\n",
217 (unsigned long long)curino->st.st_dev,
218 (unsigned long long)curino->st.st_ino);
219 }
220 }
221 if (S_ISLNK(cur->type)) {
222 char slink[PATH_MAX+1];
223 int llen;
224
225 llen = readlink(path, slink, sizeof(slink) - 1);
226 if (llen == -1)
227 err(1, "Readlink `%s'", path);
228 slink[llen] = '\0';
229 cur->symlink = estrdup(slink);
230 }
231 }
232 if (closedir(dirp) == -1)
233 err(1, "Can't closedir `%s/%s'", root, dir);
234 return (sort_dir(first));
235 }
236
237 static fsnode *
create_fsnode(const char * root,const char * path,const char * name,struct stat * stbuf)238 create_fsnode(const char *root, const char *path, const char *name,
239 struct stat *stbuf)
240 {
241 fsnode *cur;
242
243 cur = ecalloc(1, sizeof(*cur));
244 cur->path = estrdup(path);
245 cur->name = estrdup(name);
246 cur->inode = ecalloc(1, sizeof(*cur->inode));
247 cur->root = root;
248 cur->type = stbuf->st_mode & S_IFMT;
249 cur->inode->nlink = 1;
250 cur->inode->st = *stbuf;
251 if (stampst.st_ino != 0)
252 set_tstamp(cur);
253 return (cur);
254 }
255
256 /*
257 * free_fsnodes --
258 * Removes node from tree and frees it and all of
259 * its descendants.
260 */
261 void
free_fsnodes(fsnode * node)262 free_fsnodes(fsnode *node)
263 {
264 fsnode *cur, *next;
265
266 assert(node != NULL);
267
268 /* for ".", start with actual parent node */
269 if (node->first == node) {
270 assert(node->name[0] == '.' && node->name[1] == '\0');
271 if (node->parent) {
272 assert(node->parent->child == node);
273 node = node->parent;
274 }
275 }
276
277 /* Find ourselves in our sibling list and unlink */
278 if (node->first != node) {
279 for (cur = node->first; cur->next; cur = cur->next) {
280 if (cur->next == node) {
281 cur->next = node->next;
282 node->next = NULL;
283 break;
284 }
285 }
286 }
287
288 for (cur = node; cur != NULL; cur = next) {
289 next = cur->next;
290 if (cur->child) {
291 cur->child->parent = NULL;
292 free_fsnodes(cur->child);
293 }
294 if (cur->inode->nlink-- == 1)
295 free(cur->inode);
296 if (cur->symlink)
297 free(cur->symlink);
298 free(cur->path);
299 free(cur->name);
300 free(cur);
301 }
302 }
303
304 /*
305 * apply_specfile --
306 * read in the mtree(8) specfile, and apply it to the tree
307 * at dir,parent. parameters in parent on equivalent types
308 * will be changed to those found in specfile, and missing
309 * entries will be added.
310 */
311 void
apply_specfile(const char * specfile,const char * dir,fsnode * parent,int speconly)312 apply_specfile(const char *specfile, const char *dir, fsnode *parent, int speconly)
313 {
314 struct timeval start;
315 FILE *fp;
316 NODE *root;
317
318 assert(specfile != NULL);
319 assert(parent != NULL);
320
321 if (debug & DEBUG_APPLY_SPECFILE)
322 printf("apply_specfile: %s, %s %p\n", specfile, dir, parent);
323
324 /* read in the specfile */
325 if ((fp = fopen(specfile, "r")) == NULL)
326 err(1, "Can't open `%s'", specfile);
327 TIMER_START(start);
328 root = spec(fp);
329 TIMER_RESULTS(start, "spec");
330 if (fclose(fp) == EOF)
331 err(1, "Can't close `%s'", specfile);
332
333 /* perform some sanity checks */
334 if (root == NULL)
335 errx(1, "Specfile `%s' did not contain a tree", specfile);
336 assert(strcmp(root->name, ".") == 0);
337 assert(root->type == F_DIR);
338
339 /* merge in the changes */
340 apply_specdir(dir, root, parent, speconly);
341
342 free_nodes(root);
343 }
344
345 static void
apply_specdir(const char * dir,NODE * specnode,fsnode * dirnode,int speconly)346 apply_specdir(const char *dir, NODE *specnode, fsnode *dirnode, int speconly)
347 {
348 char path[MAXPATHLEN + 1];
349 NODE *curnode;
350 fsnode *curfsnode;
351
352 assert(specnode != NULL);
353 assert(dirnode != NULL);
354
355 if (debug & DEBUG_APPLY_SPECFILE)
356 printf("apply_specdir: %s %p %p\n", dir, specnode, dirnode);
357
358 if (specnode->type != F_DIR)
359 errx(1, "Specfile node `%s/%s' is not a directory",
360 dir, specnode->name);
361 if (dirnode->type != S_IFDIR)
362 errx(1, "Directory node `%s/%s' is not a directory",
363 dir, dirnode->name);
364
365 apply_specentry(dir, specnode, dirnode);
366
367 /* Remove any filesystem nodes not found in specfile */
368 /* XXX inefficient. This is O^2 in each dir and it would
369 * have been better never to have walked this part of the tree
370 * to begin with
371 */
372 if (speconly) {
373 fsnode *next;
374 assert(dirnode->name[0] == '.' && dirnode->name[1] == '\0');
375 for (curfsnode = dirnode->next; curfsnode != NULL; curfsnode = next) {
376 next = curfsnode->next;
377 for (curnode = specnode->child; curnode != NULL;
378 curnode = curnode->next) {
379 if (strcmp(curnode->name, curfsnode->name) == 0)
380 break;
381 }
382 if (curnode == NULL) {
383 if (debug & DEBUG_APPLY_SPECONLY) {
384 printf("apply_specdir: trimming %s/%s %p\n", dir, curfsnode->name, curfsnode);
385 }
386 free_fsnodes(curfsnode);
387 }
388 }
389 }
390
391 /* now walk specnode->child matching up with dirnode */
392 for (curnode = specnode->child; curnode != NULL;
393 curnode = curnode->next) {
394 if (debug & DEBUG_APPLY_SPECENTRY)
395 printf("apply_specdir: spec %s\n",
396 curnode->name);
397 for (curfsnode = dirnode->next; curfsnode != NULL;
398 curfsnode = curfsnode->next) {
399 #if 0 /* too verbose for now */
400 if (debug & DEBUG_APPLY_SPECENTRY)
401 printf("apply_specdir: dirent %s\n",
402 curfsnode->name);
403 #endif
404 if (strcmp(curnode->name, curfsnode->name) == 0)
405 break;
406 }
407 if ((size_t)snprintf(path, sizeof(path), "%s/%s", dir,
408 curnode->name) >= sizeof(path))
409 errx(1, "Pathname too long.");
410 if (curfsnode == NULL) { /* need new entry */
411 struct stat stbuf;
412
413 /*
414 * don't add optional spec entries
415 * that lack an existing fs entry
416 */
417 if ((curnode->flags & F_OPT) &&
418 lstat(path, &stbuf) == -1)
419 continue;
420
421 /* check that enough info is provided */
422 #define NODETEST(t, m) \
423 if (!(t)) \
424 errx(1, "`%s': %s not provided", path, m)
425 NODETEST(curnode->flags & F_TYPE, "type");
426 NODETEST(curnode->flags & F_MODE, "mode");
427 /* XXX: require F_TIME ? */
428 NODETEST(curnode->flags & F_GID ||
429 curnode->flags & F_GNAME, "group");
430 NODETEST(curnode->flags & F_UID ||
431 curnode->flags & F_UNAME, "user");
432 /* if (curnode->type == F_BLOCK || curnode->type == F_CHAR)
433 NODETEST(curnode->flags & F_DEV,
434 "device number");*/
435 #undef NODETEST
436
437 if (debug & DEBUG_APPLY_SPECFILE)
438 printf("apply_specdir: adding %s\n",
439 curnode->name);
440 /* build minimal fsnode */
441 memset(&stbuf, 0, sizeof(stbuf));
442 stbuf.st_mode = nodetoino(curnode->type);
443 stbuf.st_nlink = 1;
444 stbuf.st_mtime = stbuf.st_atime =
445 stbuf.st_ctime = start_time.tv_sec;
446 #if HAVE_STRUCT_STAT_ST_MTIMENSEC
447 stbuf.st_mtimensec = stbuf.st_atimensec =
448 stbuf.st_ctimensec = start_time.tv_nsec;
449 #endif
450 curfsnode = create_fsnode(".", ".", curnode->name,
451 &stbuf);
452 curfsnode->parent = dirnode->parent;
453 curfsnode->first = dirnode;
454 curfsnode->next = dirnode->next;
455 dirnode->next = curfsnode;
456 if (curfsnode->type == S_IFDIR) {
457 /* for dirs, make "." entry as well */
458 curfsnode->child = create_fsnode(".", ".", ".",
459 &stbuf);
460 curfsnode->child->parent = curfsnode;
461 curfsnode->child->first = curfsnode->child;
462 }
463 if (curfsnode->type == S_IFLNK) {
464 assert(curnode->slink != NULL);
465 /* for symlinks, copy the target */
466 curfsnode->symlink = estrdup(curnode->slink);
467 }
468 }
469 apply_specentry(dir, curnode, curfsnode);
470 if (curnode->type == F_DIR) {
471 if (curfsnode->type != S_IFDIR)
472 errx(1, "`%s' is not a directory", path);
473 assert (curfsnode->child != NULL);
474 apply_specdir(path, curnode, curfsnode->child, speconly);
475 }
476 }
477 }
478
479 static void
apply_specentry(const char * dir,NODE * specnode,fsnode * dirnode)480 apply_specentry(const char *dir, NODE *specnode, fsnode *dirnode)
481 {
482
483 assert(specnode != NULL);
484 assert(dirnode != NULL);
485
486 if (nodetoino(specnode->type) != dirnode->type)
487 errx(1, "`%s/%s' type mismatch: specfile %s, tree %s",
488 dir, specnode->name, inode_type(nodetoino(specnode->type)),
489 inode_type(dirnode->type));
490
491 if (debug & DEBUG_APPLY_SPECENTRY)
492 printf("apply_specentry: %s/%s\n", dir, dirnode->name);
493
494 #define ASEPRINT(t, b, o, n) \
495 if (debug & DEBUG_APPLY_SPECENTRY) \
496 printf("\t\t\tchanging %s from " b " to " b "\n", \
497 t, o, n)
498
499 if (specnode->flags & (F_GID | F_GNAME)) {
500 ASEPRINT("gid", "%d",
501 dirnode->inode->st.st_gid, specnode->st_gid);
502 dirnode->inode->st.st_gid = specnode->st_gid;
503 }
504 if (specnode->flags & F_MODE) {
505 ASEPRINT("mode", "%#o",
506 dirnode->inode->st.st_mode & ALLPERMS, specnode->st_mode);
507 dirnode->inode->st.st_mode &= ~ALLPERMS;
508 dirnode->inode->st.st_mode |= (specnode->st_mode & ALLPERMS);
509 }
510 /* XXX: ignoring F_NLINK for now */
511 if (specnode->flags & F_SIZE) {
512 ASEPRINT("size", "%lld",
513 (long long)dirnode->inode->st.st_size,
514 (long long)specnode->st_size);
515 dirnode->inode->st.st_size = specnode->st_size;
516 }
517 if (specnode->flags & F_SLINK) {
518 assert(dirnode->symlink != NULL);
519 assert(specnode->slink != NULL);
520 ASEPRINT("symlink", "%s", dirnode->symlink, specnode->slink);
521 free(dirnode->symlink);
522 dirnode->symlink = estrdup(specnode->slink);
523 }
524 if (specnode->flags & F_TIME) {
525 ASEPRINT("time", "%ld",
526 (long)dirnode->inode->st.st_mtime,
527 (long)specnode->st_mtimespec.tv_sec);
528 dirnode->inode->st.st_mtime = specnode->st_mtimespec.tv_sec;
529 dirnode->inode->st.st_atime = specnode->st_mtimespec.tv_sec;
530 dirnode->inode->st.st_ctime = start_time.tv_sec;
531 #if HAVE_STRUCT_STAT_ST_MTIMENSEC
532 dirnode->inode->st.st_mtimensec = specnode->st_mtimespec.tv_nsec;
533 dirnode->inode->st.st_atimensec = specnode->st_mtimespec.tv_nsec;
534 dirnode->inode->st.st_ctimensec = start_time.tv_nsec;
535 #endif
536 }
537 if (specnode->flags & (F_UID | F_UNAME)) {
538 ASEPRINT("uid", "%d",
539 dirnode->inode->st.st_uid, specnode->st_uid);
540 dirnode->inode->st.st_uid = specnode->st_uid;
541 }
542 if (specnode->flags & F_FLAGS) {
543 ASEPRINT("flags", "%#lX",
544 (unsigned long)FSINODE_ST_FLAGS(*dirnode->inode),
545 (unsigned long)specnode->st_flags);
546 FSINODE_ST_FLAGS(*dirnode->inode) = specnode->st_flags;
547 }
548 /* if (specnode->flags & F_DEV) {
549 ASEPRINT("rdev", "%#llx",
550 (unsigned long long)dirnode->inode->st.st_rdev,
551 (unsigned long long)specnode->st_rdev);
552 dirnode->inode->st.st_rdev = specnode->st_rdev;
553 }*/
554 #undef ASEPRINT
555
556 dirnode->flags |= FSNODE_F_HASSPEC;
557 }
558
559
560 /*
561 * dump_fsnodes --
562 * dump the fsnodes from `cur'
563 */
564 void
dump_fsnodes(fsnode * root)565 dump_fsnodes(fsnode *root)
566 {
567 fsnode *cur;
568 char path[MAXPATHLEN + 1];
569
570 printf("dump_fsnodes: %s %p\n", root->path, root);
571 for (cur = root; cur != NULL; cur = cur->next) {
572 if (snprintf(path, sizeof(path), "%s/%s", cur->path,
573 cur->name) >= (int)sizeof(path))
574 errx(1, "Pathname too long.");
575
576 if (debug & DEBUG_DUMP_FSNODES_VERBOSE)
577 printf("cur=%8p parent=%8p first=%8p ",
578 cur, cur->parent, cur->first);
579 printf("%7s: %s", inode_type(cur->type), path);
580 if (S_ISLNK(cur->type)) {
581 assert(cur->symlink != NULL);
582 printf(" -> %s", cur->symlink);
583 } else {
584 assert (cur->symlink == NULL);
585 }
586 if (cur->inode->nlink > 1)
587 printf(", nlinks=%d", cur->inode->nlink);
588 putchar('\n');
589
590 if (cur->child) {
591 assert (cur->type == S_IFDIR);
592 dump_fsnodes(cur->child);
593 }
594 }
595 printf("dump_fsnodes: finished %s/%s\n", root->path, root->name);
596 }
597
598
599 /*
600 * inode_type --
601 * for a given inode type `mode', return a descriptive string.
602 * for most cases, uses inotype() from mtree/misc.c
603 */
604 const char *
inode_type(mode_t mode)605 inode_type(mode_t mode)
606 {
607 if (S_ISREG(mode))
608 return ("file");
609 if (S_ISLNK(mode))
610 return ("symlink");
611 if (S_ISDIR(mode))
612 return ("dir");
613 if (S_ISFIFO(mode))
614 return ("fifo");
615 if (S_ISSOCK(mode))
616 return ("socket");
617 /* XXX should not happen but handle them */
618 if (S_ISCHR(mode))
619 return ("char");
620 if (S_ISBLK(mode))
621 return ("block");
622 return ("unknown");
623 }
624
625
626 /*
627 * link_check --
628 * return pointer to fsinode matching `entry's st_ino & st_dev if it exists,
629 * otherwise add `entry' to table and return NULL
630 */
631 /* This was borrowed from du.c and tweaked to keep an fsnode
632 * pointer instead. -- dbj@netbsd.org
633 */
634 fsinode *
link_check(fsinode * entry)635 link_check(fsinode *entry)
636 {
637 static struct entry {
638 fsinode *data;
639 } *htable;
640 static int htshift; /* log(allocated size) */
641 static int htmask; /* allocated size - 1 */
642 static int htused; /* 2*number of insertions */
643 int h, h2;
644 uint64_t tmp;
645 /* this constant is (1<<64)/((1+sqrt(5))/2)
646 * aka (word size)/(golden ratio)
647 */
648 const uint64_t HTCONST = 11400714819323198485ULL;
649 const int HTBITS = 64;
650
651 /* Never store zero in hashtable */
652 assert(entry);
653
654 /* Extend hash table if necessary, keep load under 0.5 */
655 if (htused<<1 >= htmask) {
656 struct entry *ohtable;
657
658 if (!htable)
659 htshift = 10; /* starting hashtable size */
660 else
661 htshift++; /* exponential hashtable growth */
662
663 htmask = (1 << htshift) - 1;
664 htused = 0;
665
666 ohtable = htable;
667 htable = ecalloc(htmask+1, sizeof(*htable));
668 /* populate newly allocated hashtable */
669 if (ohtable) {
670 int i;
671 for (i = 0; i <= htmask>>1; i++)
672 if (ohtable[i].data)
673 link_check(ohtable[i].data);
674 free(ohtable);
675 }
676 }
677
678 /* multiplicative hashing */
679 tmp = entry->st.st_dev;
680 tmp <<= HTBITS>>1;
681 tmp |= entry->st.st_ino;
682 tmp *= HTCONST;
683 h = tmp >> (HTBITS - htshift);
684 h2 = 1 | ( tmp >> (HTBITS - (htshift<<1) - 1)); /* must be odd */
685
686 /* open address hashtable search with double hash probing */
687 while (htable[h].data) {
688 if ((htable[h].data->st.st_ino == entry->st.st_ino) &&
689 (htable[h].data->st.st_dev == entry->st.st_dev)) {
690 return htable[h].data;
691 }
692 h = (h + h2) & htmask;
693 }
694
695 /* Insert the current entry into hashtable */
696 htable[h].data = entry;
697 htused++;
698 return NULL;
699 }
700