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