1/*
2 * Utilities for paths and pathnames
3 */
4#include "cache.h"
5#include "strbuf.h"
6#include "string-list.h"
7#ifndef get_st_mode_bits
9/*
10 * The replacement lstat(2) we use on Cygwin is incomplete and
11 * may return wrong permission bits. Most of the time we do not care,
12 * but the callsites of this wrapper do care.
13 */
14int get_st_mode_bits(const char *path, int *mode)
15{
16 struct stat st;
17 if (lstat(path, &st) < 0)
18 return -1;
19 *mode = st.st_mode;
20 return 0;
21}
22#endif
23static char bad_path[] = "/bad-path/";
25static char *get_pathname(void)
27{
28 static char pathname_array[4][PATH_MAX];
29 static int index;
30 return pathname_array[3 & ++index];
31}
32static char *cleanup_path(char *path)
34{
35 /* Clean it up */
36 if (!memcmp(path, "./", 2)) {
37 path += 2;
38 while (*path == '/')
39 path++;
40 }
41 return path;
42}
43char *mksnpath(char *buf, size_t n, const char *fmt, ...)
45{
46 va_list args;
47 unsigned len;
48 va_start(args, fmt);
50 len = vsnprintf(buf, n, fmt, args);
51 va_end(args);
52 if (len >= n) {
53 strlcpy(buf, bad_path, n);
54 return buf;
55 }
56 return cleanup_path(buf);
57}
58static char *vsnpath(char *buf, size_t n, const char *fmt, va_list args)
60{
61 const char *git_dir = get_git_dir();
62 size_t len;
63 len = strlen(git_dir);
65 if (n < len + 1)
66 goto bad;
67 memcpy(buf, git_dir, len);
68 if (len && !is_dir_sep(git_dir[len-1]))
69 buf[len++] = '/';
70 len += vsnprintf(buf + len, n - len, fmt, args);
71 if (len >= n)
72 goto bad;
73 return cleanup_path(buf);
74bad:
75 strlcpy(buf, bad_path, n);
76 return buf;
77}
78char *git_snpath(char *buf, size_t n, const char *fmt, ...)
80{
81 char *ret;
82 va_list args;
83 va_start(args, fmt);
84 ret = vsnpath(buf, n, fmt, args);
85 va_end(args);
86 return ret;
87}
88char *git_pathdup(const char *fmt, ...)
90{
91 char path[PATH_MAX], *ret;
92 va_list args;
93 va_start(args, fmt);
94 ret = vsnpath(path, sizeof(path), fmt, args);
95 va_end(args);
96 return xstrdup(ret);
97}
98char *mkpathdup(const char *fmt, ...)
100{
101 char *path;
102 struct strbuf sb = STRBUF_INIT;
103 va_list args;
104 va_start(args, fmt);
106 strbuf_vaddf(&sb, fmt, args);
107 va_end(args);
108 path = xstrdup(cleanup_path(sb.buf));
109 strbuf_release(&sb);
111 return path;
112}
113char *mkpath(const char *fmt, ...)
115{
116 va_list args;
117 unsigned len;
118 char *pathname = get_pathname();
119 va_start(args, fmt);
121 len = vsnprintf(pathname, PATH_MAX, fmt, args);
122 va_end(args);
123 if (len >= PATH_MAX)
124 return bad_path;
125 return cleanup_path(pathname);
126}
127char *git_path(const char *fmt, ...)
129{
130 char *pathname = get_pathname();
131 va_list args;
132 char *ret;
133 va_start(args, fmt);
135 ret = vsnpath(pathname, PATH_MAX, fmt, args);
136 va_end(args);
137 return ret;
138}
139void home_config_paths(char **global, char **xdg, char *file)
141{
142 char *xdg_home = getenv("XDG_CONFIG_HOME");
143 char *home = getenv("HOME");
144 char *to_free = NULL;
145 if (!home) {
147 if (global)
148 *global = NULL;
149 } else {
150 if (!xdg_home) {
151 to_free = mkpathdup("%s/.config", home);
152 xdg_home = to_free;
153 }
154 if (global)
155 *global = mkpathdup("%s/.gitconfig", home);
156 }
157 if (!xdg_home)
159 *xdg = NULL;
160 else
161 *xdg = mkpathdup("%s/git/%s", xdg_home, file);
162 free(to_free);
164}
165char *git_path_submodule(const char *path, const char *fmt, ...)
167{
168 char *pathname = get_pathname();
169 struct strbuf buf = STRBUF_INIT;
170 const char *git_dir;
171 va_list args;
172 unsigned len;
173 len = strlen(path);
175 if (len > PATH_MAX-100)
176 return bad_path;
177 strbuf_addstr(&buf, path);
179 if (len && path[len-1] != '/')
180 strbuf_addch(&buf, '/');
181 strbuf_addstr(&buf, ".git");
182 git_dir = read_gitfile(buf.buf);
184 if (git_dir) {
185 strbuf_reset(&buf);
186 strbuf_addstr(&buf, git_dir);
187 }
188 strbuf_addch(&buf, '/');
189 if (buf.len >= PATH_MAX)
191 return bad_path;
192 memcpy(pathname, buf.buf, buf.len + 1);
193 strbuf_release(&buf);
195 len = strlen(pathname);
196 va_start(args, fmt);
198 len += vsnprintf(pathname + len, PATH_MAX - len, fmt, args);
199 va_end(args);
200 if (len >= PATH_MAX)
201 return bad_path;
202 return cleanup_path(pathname);
203}
204int validate_headref(const char *path)
206{
207 struct stat st;
208 char *buf, buffer[256];
209 unsigned char sha1[20];
210 int fd;
211 ssize_t len;
212 if (lstat(path, &st) < 0)
214 return -1;
215 /* Make sure it is a "refs/.." symlink */
217 if (S_ISLNK(st.st_mode)) {
218 len = readlink(path, buffer, sizeof(buffer)-1);
219 if (len >= 5 && !memcmp("refs/", buffer, 5))
220 return 0;
221 return -1;
222 }
223 /*
225 * Anything else, just open it and try to see if it is a symbolic ref.
226 */
227 fd = open(path, O_RDONLY);
228 if (fd < 0)
229 return -1;
230 len = read_in_full(fd, buffer, sizeof(buffer)-1);
231 close(fd);
232 /*
234 * Is it a symbolic ref?
235 */
236 if (len < 4)
237 return -1;
238 if (!memcmp("ref:", buffer, 4)) {
239 buf = buffer + 4;
240 len -= 4;
241 while (len && isspace(*buf))
242 buf++, len--;
243 if (len >= 5 && !memcmp("refs/", buf, 5))
244 return 0;
245 }
246 /*
248 * Is this a detached HEAD?
249 */
250 if (!get_sha1_hex(buffer, sha1))
251 return 0;
252 return -1;
254}
255static struct passwd *getpw_str(const char *username, size_t len)
257{
258 struct passwd *pw;
259 char *username_z = xmalloc(len + 1);
260 memcpy(username_z, username, len);
261 username_z[len] = '\0';
262 pw = getpwnam(username_z);
263 free(username_z);
264 return pw;
265}
266/*
268 * Return a string with ~ and ~user expanded via getpw*. If buf != NULL,
269 * then it is a newly allocated string. Returns NULL on getpw failure or
270 * if path is NULL.
271 */
272char *expand_user_path(const char *path)
273{
274 struct strbuf user_path = STRBUF_INIT;
275 const char *first_slash = strchrnul(path, '/');
276 const char *to_copy = path;
277 if (path == NULL)
279 goto return_null;
280 if (path[0] == '~') {
281 const char *username = path + 1;
282 size_t username_len = first_slash - username;
283 if (username_len == 0) {
284 const char *home = getenv("HOME");
285 if (!home)
286 goto return_null;
287 strbuf_add(&user_path, home, strlen(home));
288 } else {
289 struct passwd *pw = getpw_str(username, username_len);
290 if (!pw)
291 goto return_null;
292 strbuf_add(&user_path, pw->pw_dir, strlen(pw->pw_dir));
293 }
294 to_copy = first_slash;
295 }
296 strbuf_add(&user_path, to_copy, strlen(to_copy));
297 return strbuf_detach(&user_path, NULL);
298return_null:
299 strbuf_release(&user_path);
300 return NULL;
301}
302/*
304 * First, one directory to try is determined by the following algorithm.
305 *
306 * (0) If "strict" is given, the path is used as given and no DWIM is
307 * done. Otherwise:
308 * (1) "~/path" to mean path under the running user's home directory;
309 * (2) "~user/path" to mean path under named user's home directory;
310 * (3) "relative/path" to mean cwd relative directory; or
311 * (4) "/absolute/path" to mean absolute directory.
312 *
313 * Unless "strict" is given, we try access() for existence of "%s.git/.git",
314 * "%s/.git", "%s.git", "%s" in this order. The first one that exists is
315 * what we try.
316 *
317 * Second, we try chdir() to that. Upon failure, we return NULL.
318 *
319 * Then, we try if the current directory is a valid git repository.
320 * Upon failure, we return NULL.
321 *
322 * If all goes well, we return the directory we used to chdir() (but
323 * before ~user is expanded), avoiding getcwd() resolving symbolic
324 * links. User relative paths are also returned as they are given,
325 * except DWIM suffixing.
326 */
327const char *enter_repo(const char *path, int strict)
328{
329 static char used_path[PATH_MAX];
330 static char validated_path[PATH_MAX];
331 if (!path)
333 return NULL;
334 if (!strict) {
336 static const char *suffix[] = {
337 "/.git", "", ".git/.git", ".git", NULL,
338 };
339 const char *gitfile;
340 int len = strlen(path);
341 int i;
342 while ((1 < len) && (path[len-1] == '/'))
343 len--;
344 if (PATH_MAX <= len)
346 return NULL;
347 strncpy(used_path, path, len); used_path[len] = 0 ;
348 strcpy(validated_path, used_path);
349 if (used_path[0] == '~') {
351 char *newpath = expand_user_path(used_path);
352 if (!newpath || (PATH_MAX - 10 < strlen(newpath))) {
353 free(newpath);
354 return NULL;
355 }
356 /*
357 * Copy back into the static buffer. A pity
358 * since newpath was not bounded, but other
359 * branches of the if are limited by PATH_MAX
360 * anyway.
361 */
362 strcpy(used_path, newpath); free(newpath);
363 }
364 else if (PATH_MAX - 10 < len)
365 return NULL;
366 len = strlen(used_path);
367 for (i = 0; suffix[i]; i++) {
368 struct stat st;
369 strcpy(used_path + len, suffix[i]);
370 if (!stat(used_path, &st) &&
371 (S_ISREG(st.st_mode) ||
372 (S_ISDIR(st.st_mode) && is_git_directory(used_path)))) {
373 strcat(validated_path, suffix[i]);
374 break;
375 }
376 }
377 if (!suffix[i])
378 return NULL;
379 gitfile = read_gitfile(used_path) ;
380 if (gitfile)
381 strcpy(used_path, gitfile);
382 if (chdir(used_path))
383 return NULL;
384 path = validated_path;
385 }
386 else if (chdir(path))
387 return NULL;
388 if (access("objects", X_OK) == 0 && access("refs", X_OK) == 0 &&
390 validate_headref("HEAD") == 0) {
391 set_git_dir(".");
392 check_repository_format();
393 return path;
394 }
395 return NULL;
397}
398static int calc_shared_perm(int mode)
400{
401 int tweak;
402 if (shared_repository < 0)
404 tweak = -shared_repository;
405 else
406 tweak = shared_repository;
407 if (!(mode & S_IWUSR))
409 tweak &= ~0222;
410 if (mode & S_IXUSR)
411 /* Copy read bits to execute bits */
412 tweak |= (tweak & 0444) >> 2;
413 if (shared_repository < 0)
414 mode = (mode & ~0777) | tweak;
415 else
416 mode |= tweak;
417 return mode;
419}
420int adjust_shared_perm(const char *path)
423{
424 int old_mode, new_mode;
425 if (!shared_repository)
427 return 0;
428 if (get_st_mode_bits(path, &old_mode) < 0)
429 return -1;
430 new_mode = calc_shared_perm(old_mode);
432 if (S_ISDIR(old_mode)) {
433 /* Copy read bits to execute bits */
434 new_mode |= (new_mode & 0444) >> 2;
435 new_mode |= FORCE_DIR_SET_GID;
436 }
437 if (((old_mode ^ new_mode) & ~S_IFMT) &&
439 chmod(path, (new_mode & ~S_IFMT)) < 0)
440 return -2;
441 return 0;
442}
443const char *relative_path(const char *abs, const char *base)
445{
446 static char buf[PATH_MAX + 1];
447 int i = 0, j = 0;
448 if (!base || !base[0])
450 return abs;
451 while (base[i]) {
452 if (is_dir_sep(base[i])) {
453 if (!is_dir_sep(abs[j]))
454 return abs;
455 while (is_dir_sep(base[i]))
456 i++;
457 while (is_dir_sep(abs[j]))
458 j++;
459 continue;
460 } else if (abs[j] != base[i]) {
461 return abs;
462 }
463 i++;
464 j++;
465 }
466 if (
467 /* "/foo" is a prefix of "/foo" */
468 abs[j] &&
469 /* "/foo" is not a prefix of "/foobar" */
470 !is_dir_sep(base[i-1]) && !is_dir_sep(abs[j])
471 )
472 return abs;
473 while (is_dir_sep(abs[j]))
474 j++;
475 if (!abs[j])
476 strcpy(buf, ".");
477 else
478 strcpy(buf, abs + j);
479 return buf;
480}
481/*
483 * It is okay if dst == src, but they should not overlap otherwise.
484 *
485 * Performs the following normalizations on src, storing the result in dst:
486 * - Ensures that components are separated by '/' (Windows only)
487 * - Squashes sequences of '/'.
488 * - Removes "." components.
489 * - Removes ".." components, and the components the precede them.
490 * Returns failure (non-zero) if a ".." component appears as first path
491 * component anytime during the normalization. Otherwise, returns success (0).
492 *
493 * Note that this function is purely textual. It does not follow symlinks,
494 * verify the existence of the path, or make any system calls.
495 */
496int normalize_path_copy(char *dst, const char *src)
497{
498 char *dst0;
499 if (has_dos_drive_prefix(src)) {
501 *dst++ = *src++;
502 *dst++ = *src++;
503 }
504 dst0 = dst;
505 if (is_dir_sep(*src)) {
507 *dst++ = '/';
508 while (is_dir_sep(*src))
509 src++;
510 }
511 for (;;) {
513 char c = *src;
514 /*
516 * A path component that begins with . could be
517 * special:
518 * (1) "." and ends -- ignore and terminate.
519 * (2) "./" -- ignore them, eat slash and continue.
520 * (3) ".." and ends -- strip one and terminate.
521 * (4) "../" -- strip one, eat slash and continue.
522 */
523 if (c == '.') {
524 if (!src[1]) {
525 /* (1) */
526 src++;
527 } else if (is_dir_sep(src[1])) {
528 /* (2) */
529 src += 2;
530 while (is_dir_sep(*src))
531 src++;
532 continue;
533 } else if (src[1] == '.') {
534 if (!src[2]) {
535 /* (3) */
536 src += 2;
537 goto up_one;
538 } else if (is_dir_sep(src[2])) {
539 /* (4) */
540 src += 3;
541 while (is_dir_sep(*src))
542 src++;
543 goto up_one;
544 }
545 }
546 }
547 /* copy up to the next '/', and eat all '/' */
549 while ((c = *src++) != '\0' && !is_dir_sep(c))
550 *dst++ = c;
551 if (is_dir_sep(c)) {
552 *dst++ = '/';
553 while (is_dir_sep(c))
554 c = *src++;
555 src--;
556 } else if (!c)
557 break;
558 continue;
559 up_one:
561 /*
562 * dst0..dst is prefix portion, and dst[-1] is '/';
563 * go up one level.
564 */
565 dst--; /* go to trailing '/' */
566 if (dst <= dst0)
567 return -1;
568 /* Windows: dst[-1] cannot be backslash anymore */
569 while (dst0 < dst && dst[-1] != '/')
570 dst--;
571 }
572 *dst = '\0';
573 return 0;
574}
575/*
577 * path = Canonical absolute path
578 * prefixes = string_list containing normalized, absolute paths without
579 * trailing slashes (except for the root directory, which is denoted by "/").
580 *
581 * Determines, for each path in prefixes, whether the "prefix"
582 * is an ancestor directory of path. Returns the length of the longest
583 * ancestor directory, excluding any trailing slashes, or -1 if no prefix
584 * is an ancestor. (Note that this means 0 is returned if prefixes is
585 * ["/"].) "/foo" is not considered an ancestor of "/foobar". Directories
586 * are not considered to be their own ancestors. path must be in a
587 * canonical form: empty components, or "." or ".." components are not
588 * allowed.
589 */
590int longest_ancestor_length(const char *path, struct string_list *prefixes)
591{
592 int i, max_len = -1;
593 if (!strcmp(path, "/"))
595 return -1;
596 for (i = 0; i < prefixes->nr; i++) {
598 const char *ceil = prefixes->items[i].string;
599 int len = strlen(ceil);
600 if (len == 1 && ceil[0] == '/')
602 len = 0; /* root matches anything, with length 0 */
603 else if (!strncmp(path, ceil, len) && path[len] == '/')
604 ; /* match of length len */
605 else
606 continue; /* no match */
607 if (len > max_len)
609 max_len = len;
610 }
611 return max_len;
613}
614/* strip arbitrary amount of directory separators at end of path */
616static inline int chomp_trailing_dir_sep(const char *path, int len)
617{
618 while (len && is_dir_sep(path[len - 1]))
619 len--;
620 return len;
621}
622/*
624 * If path ends with suffix (complete path components), returns the
625 * part before suffix (sans trailing directory separators).
626 * Otherwise returns NULL.
627 */
628char *strip_path_suffix(const char *path, const char *suffix)
629{
630 int path_len = strlen(path), suffix_len = strlen(suffix);
631 while (suffix_len) {
633 if (!path_len)
634 return NULL;
635 if (is_dir_sep(path[path_len - 1])) {
637 if (!is_dir_sep(suffix[suffix_len - 1]))
638 return NULL;
639 path_len = chomp_trailing_dir_sep(path, path_len);
640 suffix_len = chomp_trailing_dir_sep(suffix, suffix_len);
641 }
642 else if (path[--path_len] != suffix[--suffix_len])
643 return NULL;
644 }
645 if (path_len && !is_dir_sep(path[path_len - 1]))
647 return NULL;
648 return xstrndup(path, chomp_trailing_dir_sep(path, path_len));
649}
650int daemon_avoid_alias(const char *p)
652{
653 int sl, ndot;
654 /*
656 * This resurrects the belts and suspenders paranoia check by HPA
657 * done in <435560F7.4080006@zytor.com> thread, now enter_repo()
658 * does not do getcwd() based path canonicalization.
659 *
660 * sl becomes true immediately after seeing '/' and continues to
661 * be true as long as dots continue after that without intervening
662 * non-dot character.
663 */
664 if (!p || (*p != '/' && *p != '~'))
665 return -1;
666 sl = 1; ndot = 0;
667 p++;
668 while (1) {
670 char ch = *p++;
671 if (sl) {
672 if (ch == '.')
673 ndot++;
674 else if (ch == '/') {
675 if (ndot < 3)
676 /* reject //, /./ and /../ */
677 return -1;
678 ndot = 0;
679 }
680 else if (ch == 0) {
681 if (0 < ndot && ndot < 3)
682 /* reject /.$ and /..$ */
683 return -1;
684 return 0;
685 }
686 else
687 sl = ndot = 0;
688 }
689 else if (ch == 0)
690 return 0;
691 else if (ch == '/') {
692 sl = 1;
693 ndot = 0;
694 }
695 }
696}
697int offset_1st_component(const char *path)
699{
700 if (has_dos_drive_prefix(path))
701 return 2 + is_dir_sep(path[2]);
702 return is_dir_sep(path[0]);
703}