1/*
2 * Utilities for paths and pathnames
3 */
4#include "cache.h"
5#include "strbuf.h"
6#include "string-list.h"
7#include "dir.h"
8static int get_st_mode_bits(const char *path, int *mode)
10{
11 struct stat st;
12 if (lstat(path, &st) < 0)
13 return -1;
14 *mode = st.st_mode;
15 return 0;
16}
17static char bad_path[] = "/bad-path/";
19static struct strbuf *get_pathname(void)
21{
22 static struct strbuf pathname_array[4] = {
23 STRBUF_INIT, STRBUF_INIT, STRBUF_INIT, STRBUF_INIT
24 };
25 static int index;
26 struct strbuf *sb = &pathname_array[3 & ++index];
27 strbuf_reset(sb);
28 return sb;
29}
30static char *cleanup_path(char *path)
32{
33 /* Clean it up */
34 if (!memcmp(path, "./", 2)) {
35 path += 2;
36 while (*path == '/')
37 path++;
38 }
39 return path;
40}
41static void strbuf_cleanup_path(struct strbuf *sb)
43{
44 char *path = cleanup_path(sb->buf);
45 if (path > sb->buf)
46 strbuf_remove(sb, 0, path - sb->buf);
47}
48char *mksnpath(char *buf, size_t n, const char *fmt, ...)
50{
51 va_list args;
52 unsigned len;
53 va_start(args, fmt);
55 len = vsnprintf(buf, n, fmt, args);
56 va_end(args);
57 if (len >= n) {
58 strlcpy(buf, bad_path, n);
59 return buf;
60 }
61 return cleanup_path(buf);
62}
63static int dir_prefix(const char *buf, const char *dir)
65{
66 int len = strlen(dir);
67 return !strncmp(buf, dir, len) &&
68 (is_dir_sep(buf[len]) || buf[len] == '\0');
69}
70/* $buf =~ m|$dir/+$file| but without regex */
72static int is_dir_file(const char *buf, const char *dir, const char *file)
73{
74 int len = strlen(dir);
75 if (strncmp(buf, dir, len) || !is_dir_sep(buf[len]))
76 return 0;
77 while (is_dir_sep(buf[len]))
78 len++;
79 return !strcmp(buf + len, file);
80}
81static void replace_dir(struct strbuf *buf, int len, const char *newdir)
83{
84 int newlen = strlen(newdir);
85 int need_sep = (buf->buf[len] && !is_dir_sep(buf->buf[len])) &&
86 !is_dir_sep(newdir[newlen - 1]);
87 if (need_sep)
88 len--; /* keep one char, to be replaced with '/' */
89 strbuf_splice(buf, 0, len, newdir, newlen);
90 if (need_sep)
91 buf->buf[newlen] = '/';
92}
93static const char *common_list[] = {
95 "/branches", "/hooks", "/info", "!/logs", "/lost-found",
96 "/objects", "/refs", "/remotes", "/worktrees", "/rr-cache", "/svn",
97 "config", "!gc.pid", "packed-refs", "shallow",
98 NULL
99};
100static void update_common_dir(struct strbuf *buf, int git_dir_len)
102{
103 char *base = buf->buf + git_dir_len;
104 const char **p;
105 if (is_dir_file(base, "logs", "HEAD") ||
107 is_dir_file(base, "info", "sparse-checkout"))
108 return; /* keep this in $GIT_DIR */
109 for (p = common_list; *p; p++) {
110 const char *path = *p;
111 int is_dir = 0;
112 if (*path == '!')
113 path++;
114 if (*path == '/') {
115 path++;
116 is_dir = 1;
117 }
118 if (is_dir && dir_prefix(base, path)) {
119 replace_dir(buf, git_dir_len, get_git_common_dir());
120 return;
121 }
122 if (!is_dir && !strcmp(base, path)) {
123 replace_dir(buf, git_dir_len, get_git_common_dir());
124 return;
125 }
126 }
127}
128void report_linked_checkout_garbage(void)
130{
131 struct strbuf sb = STRBUF_INIT;
132 const char **p;
133 int len;
134 if (!git_common_dir_env)
136 return;
137 strbuf_addf(&sb, "%s/", get_git_dir());
138 len = sb.len;
139 for (p = common_list; *p; p++) {
140 const char *path = *p;
141 if (*path == '!')
142 continue;
143 strbuf_setlen(&sb, len);
144 strbuf_addstr(&sb, path);
145 if (file_exists(sb.buf))
146 report_garbage("unused in linked checkout", sb.buf);
147 }
148 strbuf_release(&sb);
149}
150static void adjust_git_path(struct strbuf *buf, int git_dir_len)
152{
153 const char *base = buf->buf + git_dir_len;
154 if (git_graft_env && is_dir_file(base, "info", "grafts"))
155 strbuf_splice(buf, 0, buf->len,
156 get_graft_file(), strlen(get_graft_file()));
157 else if (git_index_env && !strcmp(base, "index"))
158 strbuf_splice(buf, 0, buf->len,
159 get_index_file(), strlen(get_index_file()));
160 else if (git_db_env && dir_prefix(base, "objects"))
161 replace_dir(buf, git_dir_len + 7, get_object_directory());
162 else if (git_common_dir_env)
163 update_common_dir(buf, git_dir_len);
164}
165static void do_git_path(struct strbuf *buf, const char *fmt, va_list args)
167{
168 int gitdir_len;
169 strbuf_addstr(buf, get_git_dir());
170 if (buf->len && !is_dir_sep(buf->buf[buf->len - 1]))
171 strbuf_addch(buf, '/');
172 gitdir_len = buf->len;
173 strbuf_vaddf(buf, fmt, args);
174 adjust_git_path(buf, gitdir_len);
175 strbuf_cleanup_path(buf);
176}
177void strbuf_git_path(struct strbuf *sb, const char *fmt, ...)
179{
180 va_list args;
181 va_start(args, fmt);
182 do_git_path(sb, fmt, args);
183 va_end(args);
184}
185const char *git_path(const char *fmt, ...)
187{
188 struct strbuf *pathname = get_pathname();
189 va_list args;
190 va_start(args, fmt);
191 do_git_path(pathname, fmt, args);
192 va_end(args);
193 return pathname->buf;
194}
195char *git_pathdup(const char *fmt, ...)
197{
198 struct strbuf path = STRBUF_INIT;
199 va_list args;
200 va_start(args, fmt);
201 do_git_path(&path, fmt, args);
202 va_end(args);
203 return strbuf_detach(&path, NULL);
204}
205char *mkpathdup(const char *fmt, ...)
207{
208 struct strbuf sb = STRBUF_INIT;
209 va_list args;
210 va_start(args, fmt);
211 strbuf_vaddf(&sb, fmt, args);
212 va_end(args);
213 strbuf_cleanup_path(&sb);
214 return strbuf_detach(&sb, NULL);
215}
216const char *mkpath(const char *fmt, ...)
218{
219 va_list args;
220 struct strbuf *pathname = get_pathname();
221 va_start(args, fmt);
222 strbuf_vaddf(pathname, fmt, args);
223 va_end(args);
224 return cleanup_path(pathname->buf);
225}
226void home_config_paths(char **global, char **xdg, char *file)
228{
229 char *xdg_home = getenv("XDG_CONFIG_HOME");
230 char *home = getenv("HOME");
231 char *to_free = NULL;
232 if (!home) {
234 if (global)
235 *global = NULL;
236 } else {
237 if (!xdg_home) {
238 to_free = mkpathdup("%s/.config", home);
239 xdg_home = to_free;
240 }
241 if (global)
242 *global = mkpathdup("%s/.gitconfig", home);
243 }
244 if (xdg) {
246 if (!xdg_home)
247 *xdg = NULL;
248 else
249 *xdg = mkpathdup("%s/git/%s", xdg_home, file);
250 }
251 free(to_free);
253}
254const char *git_path_submodule(const char *path, const char *fmt, ...)
256{
257 struct strbuf *buf = get_pathname();
258 const char *git_dir;
259 va_list args;
260 strbuf_addstr(buf, path);
262 if (buf->len && buf->buf[buf->len - 1] != '/')
263 strbuf_addch(buf, '/');
264 strbuf_addstr(buf, ".git");
265 git_dir = read_gitfile(buf->buf);
267 if (git_dir) {
268 strbuf_reset(buf);
269 strbuf_addstr(buf, git_dir);
270 }
271 strbuf_addch(buf, '/');
272 va_start(args, fmt);
274 strbuf_vaddf(buf, fmt, args);
275 va_end(args);
276 strbuf_cleanup_path(buf);
277 return buf->buf;
278}
279int validate_headref(const char *path)
281{
282 struct stat st;
283 char *buf, buffer[256];
284 unsigned char sha1[20];
285 int fd;
286 ssize_t len;
287 if (lstat(path, &st) < 0)
289 return -1;
290 /* Make sure it is a "refs/.." symlink */
292 if (S_ISLNK(st.st_mode)) {
293 len = readlink(path, buffer, sizeof(buffer)-1);
294 if (len >= 5 && !memcmp("refs/", buffer, 5))
295 return 0;
296 return -1;
297 }
298 /*
300 * Anything else, just open it and try to see if it is a symbolic ref.
301 */
302 fd = open(path, O_RDONLY);
303 if (fd < 0)
304 return -1;
305 len = read_in_full(fd, buffer, sizeof(buffer)-1);
306 close(fd);
307 /*
309 * Is it a symbolic ref?
310 */
311 if (len < 4)
312 return -1;
313 if (!memcmp("ref:", buffer, 4)) {
314 buf = buffer + 4;
315 len -= 4;
316 while (len && isspace(*buf))
317 buf++, len--;
318 if (len >= 5 && !memcmp("refs/", buf, 5))
319 return 0;
320 }
321 /*
323 * Is this a detached HEAD?
324 */
325 if (!get_sha1_hex(buffer, sha1))
326 return 0;
327 return -1;
329}
330static struct passwd *getpw_str(const char *username, size_t len)
332{
333 struct passwd *pw;
334 char *username_z = xmemdupz(username, len);
335 pw = getpwnam(username_z);
336 free(username_z);
337 return pw;
338}
339/*
341 * Return a string with ~ and ~user expanded via getpw*. If buf != NULL,
342 * then it is a newly allocated string. Returns NULL on getpw failure or
343 * if path is NULL.
344 */
345char *expand_user_path(const char *path)
346{
347 struct strbuf user_path = STRBUF_INIT;
348 const char *to_copy = path;
349 if (path == NULL)
351 goto return_null;
352 if (path[0] == '~') {
353 const char *first_slash = strchrnul(path, '/');
354 const char *username = path + 1;
355 size_t username_len = first_slash - username;
356 if (username_len == 0) {
357 const char *home = getenv("HOME");
358 if (!home)
359 goto return_null;
360 strbuf_addstr(&user_path, home);
361 } else {
362 struct passwd *pw = getpw_str(username, username_len);
363 if (!pw)
364 goto return_null;
365 strbuf_addstr(&user_path, pw->pw_dir);
366 }
367 to_copy = first_slash;
368 }
369 strbuf_addstr(&user_path, to_copy);
370 return strbuf_detach(&user_path, NULL);
371return_null:
372 strbuf_release(&user_path);
373 return NULL;
374}
375/*
377 * First, one directory to try is determined by the following algorithm.
378 *
379 * (0) If "strict" is given, the path is used as given and no DWIM is
380 * done. Otherwise:
381 * (1) "~/path" to mean path under the running user's home directory;
382 * (2) "~user/path" to mean path under named user's home directory;
383 * (3) "relative/path" to mean cwd relative directory; or
384 * (4) "/absolute/path" to mean absolute directory.
385 *
386 * Unless "strict" is given, we try access() for existence of "%s.git/.git",
387 * "%s/.git", "%s.git", "%s" in this order. The first one that exists is
388 * what we try.
389 *
390 * Second, we try chdir() to that. Upon failure, we return NULL.
391 *
392 * Then, we try if the current directory is a valid git repository.
393 * Upon failure, we return NULL.
394 *
395 * If all goes well, we return the directory we used to chdir() (but
396 * before ~user is expanded), avoiding getcwd() resolving symbolic
397 * links. User relative paths are also returned as they are given,
398 * except DWIM suffixing.
399 */
400const char *enter_repo(const char *path, int strict)
401{
402 static char used_path[PATH_MAX];
403 static char validated_path[PATH_MAX];
404 if (!path)
406 return NULL;
407 if (!strict) {
409 static const char *suffix[] = {
410 "/.git", "", ".git/.git", ".git", NULL,
411 };
412 const char *gitfile;
413 int len = strlen(path);
414 int i;
415 while ((1 < len) && (path[len-1] == '/'))
416 len--;
417 if (PATH_MAX <= len)
419 return NULL;
420 strncpy(used_path, path, len); used_path[len] = 0 ;
421 strcpy(validated_path, used_path);
422 if (used_path[0] == '~') {
424 char *newpath = expand_user_path(used_path);
425 if (!newpath || (PATH_MAX - 10 < strlen(newpath))) {
426 free(newpath);
427 return NULL;
428 }
429 /*
430 * Copy back into the static buffer. A pity
431 * since newpath was not bounded, but other
432 * branches of the if are limited by PATH_MAX
433 * anyway.
434 */
435 strcpy(used_path, newpath); free(newpath);
436 }
437 else if (PATH_MAX - 10 < len)
438 return NULL;
439 len = strlen(used_path);
440 for (i = 0; suffix[i]; i++) {
441 struct stat st;
442 strcpy(used_path + len, suffix[i]);
443 if (!stat(used_path, &st) &&
444 (S_ISREG(st.st_mode) ||
445 (S_ISDIR(st.st_mode) && is_git_directory(used_path)))) {
446 strcat(validated_path, suffix[i]);
447 break;
448 }
449 }
450 if (!suffix[i])
451 return NULL;
452 gitfile = read_gitfile(used_path) ;
453 if (gitfile)
454 strcpy(used_path, gitfile);
455 if (chdir(used_path))
456 return NULL;
457 path = validated_path;
458 }
459 else if (chdir(path))
460 return NULL;
461 if (access("objects", X_OK) == 0 && access("refs", X_OK) == 0 &&
463 validate_headref("HEAD") == 0) {
464 set_git_dir(".");
465 check_repository_format();
466 return path;
467 }
468 return NULL;
470}
471static int calc_shared_perm(int mode)
473{
474 int tweak;
475 if (shared_repository < 0)
477 tweak = -shared_repository;
478 else
479 tweak = shared_repository;
480 if (!(mode & S_IWUSR))
482 tweak &= ~0222;
483 if (mode & S_IXUSR)
484 /* Copy read bits to execute bits */
485 tweak |= (tweak & 0444) >> 2;
486 if (shared_repository < 0)
487 mode = (mode & ~0777) | tweak;
488 else
489 mode |= tweak;
490 return mode;
492}
493int adjust_shared_perm(const char *path)
496{
497 int old_mode, new_mode;
498 if (!shared_repository)
500 return 0;
501 if (get_st_mode_bits(path, &old_mode) < 0)
502 return -1;
503 new_mode = calc_shared_perm(old_mode);
505 if (S_ISDIR(old_mode)) {
506 /* Copy read bits to execute bits */
507 new_mode |= (new_mode & 0444) >> 2;
508 new_mode |= FORCE_DIR_SET_GID;
509 }
510 if (((old_mode ^ new_mode) & ~S_IFMT) &&
512 chmod(path, (new_mode & ~S_IFMT)) < 0)
513 return -2;
514 return 0;
515}
516static int have_same_root(const char *path1, const char *path2)
518{
519 int is_abs1, is_abs2;
520 is_abs1 = is_absolute_path(path1);
522 is_abs2 = is_absolute_path(path2);
523 return (is_abs1 && is_abs2 && tolower(path1[0]) == tolower(path2[0])) ||
524 (!is_abs1 && !is_abs2);
525}
526/*
528 * Give path as relative to prefix.
529 *
530 * The strbuf may or may not be used, so do not assume it contains the
531 * returned path.
532 */
533const char *relative_path(const char *in, const char *prefix,
534 struct strbuf *sb)
535{
536 int in_len = in ? strlen(in) : 0;
537 int prefix_len = prefix ? strlen(prefix) : 0;
538 int in_off = 0;
539 int prefix_off = 0;
540 int i = 0, j = 0;
541 if (!in_len)
543 return "./";
544 else if (!prefix_len)
545 return in;
546 if (have_same_root(in, prefix)) {
548 /* bypass dos_drive, for "c:" is identical to "C:" */
549 if (has_dos_drive_prefix(in)) {
550 i = 2;
551 j = 2;
552 }
553 } else {
554 return in;
555 }
556 while (i < prefix_len && j < in_len && prefix[i] == in[j]) {
558 if (is_dir_sep(prefix[i])) {
559 while (is_dir_sep(prefix[i]))
560 i++;
561 while (is_dir_sep(in[j]))
562 j++;
563 prefix_off = i;
564 in_off = j;
565 } else {
566 i++;
567 j++;
568 }
569 }
570 if (
572 /* "prefix" seems like prefix of "in" */
573 i >= prefix_len &&
574 /*
575 * but "/foo" is not a prefix of "/foobar"
576 * (i.e. prefix not end with '/')
577 */
578 prefix_off < prefix_len) {
579 if (j >= in_len) {
580 /* in="/a/b", prefix="/a/b" */
581 in_off = in_len;
582 } else if (is_dir_sep(in[j])) {
583 /* in="/a/b/c", prefix="/a/b" */
584 while (is_dir_sep(in[j]))
585 j++;
586 in_off = j;
587 } else {
588 /* in="/a/bbb/c", prefix="/a/b" */
589 i = prefix_off;
590 }
591 } else if (
592 /* "in" is short than "prefix" */
593 j >= in_len &&
594 /* "in" not end with '/' */
595 in_off < in_len) {
596 if (is_dir_sep(prefix[i])) {
597 /* in="/a/b", prefix="/a/b/c/" */
598 while (is_dir_sep(prefix[i]))
599 i++;
600 in_off = in_len;
601 }
602 }
603 in += in_off;
604 in_len -= in_off;
605 if (i >= prefix_len) {
607 if (!in_len)
608 return "./";
609 else
610 return in;
611 }
612 strbuf_reset(sb);
614 strbuf_grow(sb, in_len);
615 while (i < prefix_len) {
617 if (is_dir_sep(prefix[i])) {
618 strbuf_addstr(sb, "../");
619 while (is_dir_sep(prefix[i]))
620 i++;
621 continue;
622 }
623 i++;
624 }
625 if (!is_dir_sep(prefix[prefix_len - 1]))
626 strbuf_addstr(sb, "../");
627 strbuf_addstr(sb, in);
629 return sb->buf;
631}
632/*
634 * A simpler implementation of relative_path
635 *
636 * Get relative path by removing "prefix" from "in". This function
637 * first appears in v1.5.6-1-g044bbbc, and makes git_dir shorter
638 * to increase performance when traversing the path to work_tree.
639 */
640const char *remove_leading_path(const char *in, const char *prefix)
641{
642 static char buf[PATH_MAX + 1];
643 int i = 0, j = 0;
644 if (!prefix || !prefix[0])
646 return in;
647 while (prefix[i]) {
648 if (is_dir_sep(prefix[i])) {
649 if (!is_dir_sep(in[j]))
650 return in;
651 while (is_dir_sep(prefix[i]))
652 i++;
653 while (is_dir_sep(in[j]))
654 j++;
655 continue;
656 } else if (in[j] != prefix[i]) {
657 return in;
658 }
659 i++;
660 j++;
661 }
662 if (
663 /* "/foo" is a prefix of "/foo" */
664 in[j] &&
665 /* "/foo" is not a prefix of "/foobar" */
666 !is_dir_sep(prefix[i-1]) && !is_dir_sep(in[j])
667 )
668 return in;
669 while (is_dir_sep(in[j]))
670 j++;
671 if (!in[j])
672 strcpy(buf, ".");
673 else
674 strcpy(buf, in + j);
675 return buf;
676}
677/*
679 * It is okay if dst == src, but they should not overlap otherwise.
680 *
681 * Performs the following normalizations on src, storing the result in dst:
682 * - Ensures that components are separated by '/' (Windows only)
683 * - Squashes sequences of '/'.
684 * - Removes "." components.
685 * - Removes ".." components, and the components the precede them.
686 * Returns failure (non-zero) if a ".." component appears as first path
687 * component anytime during the normalization. Otherwise, returns success (0).
688 *
689 * Note that this function is purely textual. It does not follow symlinks,
690 * verify the existence of the path, or make any system calls.
691 *
692 * prefix_len != NULL is for a specific case of prefix_pathspec():
693 * assume that src == dst and src[0..prefix_len-1] is already
694 * normalized, any time "../" eats up to the prefix_len part,
695 * prefix_len is reduced. In the end prefix_len is the remaining
696 * prefix that has not been overridden by user pathspec.
697 */
698int normalize_path_copy_len(char *dst, const char *src, int *prefix_len)
699{
700 char *dst0;
701 if (has_dos_drive_prefix(src)) {
703 *dst++ = *src++;
704 *dst++ = *src++;
705 }
706 dst0 = dst;
707 if (is_dir_sep(*src)) {
709 *dst++ = '/';
710 while (is_dir_sep(*src))
711 src++;
712 }
713 for (;;) {
715 char c = *src;
716 /*
718 * A path component that begins with . could be
719 * special:
720 * (1) "." and ends -- ignore and terminate.
721 * (2) "./" -- ignore them, eat slash and continue.
722 * (3) ".." and ends -- strip one and terminate.
723 * (4) "../" -- strip one, eat slash and continue.
724 */
725 if (c == '.') {
726 if (!src[1]) {
727 /* (1) */
728 src++;
729 } else if (is_dir_sep(src[1])) {
730 /* (2) */
731 src += 2;
732 while (is_dir_sep(*src))
733 src++;
734 continue;
735 } else if (src[1] == '.') {
736 if (!src[2]) {
737 /* (3) */
738 src += 2;
739 goto up_one;
740 } else if (is_dir_sep(src[2])) {
741 /* (4) */
742 src += 3;
743 while (is_dir_sep(*src))
744 src++;
745 goto up_one;
746 }
747 }
748 }
749 /* copy up to the next '/', and eat all '/' */
751 while ((c = *src++) != '\0' && !is_dir_sep(c))
752 *dst++ = c;
753 if (is_dir_sep(c)) {
754 *dst++ = '/';
755 while (is_dir_sep(c))
756 c = *src++;
757 src--;
758 } else if (!c)
759 break;
760 continue;
761 up_one:
763 /*
764 * dst0..dst is prefix portion, and dst[-1] is '/';
765 * go up one level.
766 */
767 dst--; /* go to trailing '/' */
768 if (dst <= dst0)
769 return -1;
770 /* Windows: dst[-1] cannot be backslash anymore */
771 while (dst0 < dst && dst[-1] != '/')
772 dst--;
773 if (prefix_len && *prefix_len > dst - dst0)
774 *prefix_len = dst - dst0;
775 }
776 *dst = '\0';
777 return 0;
778}
779int normalize_path_copy(char *dst, const char *src)
781{
782 return normalize_path_copy_len(dst, src, NULL);
783}
784/*
786 * path = Canonical absolute path
787 * prefixes = string_list containing normalized, absolute paths without
788 * trailing slashes (except for the root directory, which is denoted by "/").
789 *
790 * Determines, for each path in prefixes, whether the "prefix"
791 * is an ancestor directory of path. Returns the length of the longest
792 * ancestor directory, excluding any trailing slashes, or -1 if no prefix
793 * is an ancestor. (Note that this means 0 is returned if prefixes is
794 * ["/"].) "/foo" is not considered an ancestor of "/foobar". Directories
795 * are not considered to be their own ancestors. path must be in a
796 * canonical form: empty components, or "." or ".." components are not
797 * allowed.
798 */
799int longest_ancestor_length(const char *path, struct string_list *prefixes)
800{
801 int i, max_len = -1;
802 if (!strcmp(path, "/"))
804 return -1;
805 for (i = 0; i < prefixes->nr; i++) {
807 const char *ceil = prefixes->items[i].string;
808 int len = strlen(ceil);
809 if (len == 1 && ceil[0] == '/')
811 len = 0; /* root matches anything, with length 0 */
812 else if (!strncmp(path, ceil, len) && path[len] == '/')
813 ; /* match of length len */
814 else
815 continue; /* no match */
816 if (len > max_len)
818 max_len = len;
819 }
820 return max_len;
822}
823/* strip arbitrary amount of directory separators at end of path */
825static inline int chomp_trailing_dir_sep(const char *path, int len)
826{
827 while (len && is_dir_sep(path[len - 1]))
828 len--;
829 return len;
830}
831/*
833 * If path ends with suffix (complete path components), returns the
834 * part before suffix (sans trailing directory separators).
835 * Otherwise returns NULL.
836 */
837char *strip_path_suffix(const char *path, const char *suffix)
838{
839 int path_len = strlen(path), suffix_len = strlen(suffix);
840 while (suffix_len) {
842 if (!path_len)
843 return NULL;
844 if (is_dir_sep(path[path_len - 1])) {
846 if (!is_dir_sep(suffix[suffix_len - 1]))
847 return NULL;
848 path_len = chomp_trailing_dir_sep(path, path_len);
849 suffix_len = chomp_trailing_dir_sep(suffix, suffix_len);
850 }
851 else if (path[--path_len] != suffix[--suffix_len])
852 return NULL;
853 }
854 if (path_len && !is_dir_sep(path[path_len - 1]))
856 return NULL;
857 return xstrndup(path, chomp_trailing_dir_sep(path, path_len));
858}
859int daemon_avoid_alias(const char *p)
861{
862 int sl, ndot;
863 /*
865 * This resurrects the belts and suspenders paranoia check by HPA
866 * done in <435560F7.4080006@zytor.com> thread, now enter_repo()
867 * does not do getcwd() based path canonicalization.
868 *
869 * sl becomes true immediately after seeing '/' and continues to
870 * be true as long as dots continue after that without intervening
871 * non-dot character.
872 */
873 if (!p || (*p != '/' && *p != '~'))
874 return -1;
875 sl = 1; ndot = 0;
876 p++;
877 while (1) {
879 char ch = *p++;
880 if (sl) {
881 if (ch == '.')
882 ndot++;
883 else if (ch == '/') {
884 if (ndot < 3)
885 /* reject //, /./ and /../ */
886 return -1;
887 ndot = 0;
888 }
889 else if (ch == 0) {
890 if (0 < ndot && ndot < 3)
891 /* reject /.$ and /..$ */
892 return -1;
893 return 0;
894 }
895 else
896 sl = ndot = 0;
897 }
898 else if (ch == 0)
899 return 0;
900 else if (ch == '/') {
901 sl = 1;
902 ndot = 0;
903 }
904 }
905}