1/*
2 * I'm tired of doing "vsnprintf()" etc just to open a
3 * file, so here's a "return static buffer with printf"
4 * interface for paths.
5 *
6 * It's obviously not thread-safe. Sue me. But it's quite
7 * useful for doing things like
8 *
9 * f = open(mkpath("%s/%s.git", base, name), O_RDONLY);
10 *
11 * which is what it's designed for.
12 */
13#include "cache.h"
14#include "strbuf.h"
15static char bad_path[] = "/bad-path/";
17static char *get_pathname(void)
19{
20 static char pathname_array[4][PATH_MAX];
21 static int index;
22 return pathname_array[3 & ++index];
23}
24static char *cleanup_path(char *path)
26{
27 /* Clean it up */
28 if (!memcmp(path, "./", 2)) {
29 path += 2;
30 while (*path == '/')
31 path++;
32 }
33 return path;
34}
35char *mksnpath(char *buf, size_t n, const char *fmt, ...)
37{
38 va_list args;
39 unsigned len;
40 va_start(args, fmt);
42 len = vsnprintf(buf, n, fmt, args);
43 va_end(args);
44 if (len >= n) {
45 strlcpy(buf, bad_path, n);
46 return buf;
47 }
48 return cleanup_path(buf);
49}
50static char *git_vsnpath(char *buf, size_t n, const char *fmt, va_list args)
52{
53 const char *git_dir = get_git_dir();
54 size_t len;
55 len = strlen(git_dir);
57 if (n < len + 1)
58 goto bad;
59 memcpy(buf, git_dir, len);
60 if (len && !is_dir_sep(git_dir[len-1]))
61 buf[len++] = '/';
62 len += vsnprintf(buf + len, n - len, fmt, args);
63 if (len >= n)
64 goto bad;
65 return cleanup_path(buf);
66bad:
67 strlcpy(buf, bad_path, n);
68 return buf;
69}
70char *git_snpath(char *buf, size_t n, const char *fmt, ...)
72{
73 va_list args;
74 va_start(args, fmt);
75 (void)git_vsnpath(buf, n, fmt, args);
76 va_end(args);
77 return buf;
78}
79char *git_pathdup(const char *fmt, ...)
81{
82 char path[PATH_MAX];
83 va_list args;
84 va_start(args, fmt);
85 (void)git_vsnpath(path, sizeof(path), fmt, args);
86 va_end(args);
87 return xstrdup(path);
88}
89char *mkpath(const char *fmt, ...)
91{
92 va_list args;
93 unsigned len;
94 char *pathname = get_pathname();
95 va_start(args, fmt);
97 len = vsnprintf(pathname, PATH_MAX, fmt, args);
98 va_end(args);
99 if (len >= PATH_MAX)
100 return bad_path;
101 return cleanup_path(pathname);
102}
103char *git_path(const char *fmt, ...)
105{
106 const char *git_dir = get_git_dir();
107 char *pathname = get_pathname();
108 va_list args;
109 unsigned len;
110 len = strlen(git_dir);
112 if (len > PATH_MAX-100)
113 return bad_path;
114 memcpy(pathname, git_dir, len);
115 if (len && git_dir[len-1] != '/')
116 pathname[len++] = '/';
117 va_start(args, fmt);
118 len += vsnprintf(pathname + len, PATH_MAX - len, fmt, args);
119 va_end(args);
120 if (len >= PATH_MAX)
121 return bad_path;
122 return cleanup_path(pathname);
123}
124char *git_path_submodule(const char *path, const char *fmt, ...)
126{
127 char *pathname = get_pathname();
128 struct strbuf buf = STRBUF_INIT;
129 const char *git_dir;
130 va_list args;
131 unsigned len;
132 len = strlen(path);
134 if (len > PATH_MAX-100)
135 return bad_path;
136 strbuf_addstr(&buf, path);
138 if (len && path[len-1] != '/')
139 strbuf_addch(&buf, '/');
140 strbuf_addstr(&buf, ".git");
141 git_dir = read_gitfile_gently(buf.buf);
143 if (git_dir) {
144 strbuf_reset(&buf);
145 strbuf_addstr(&buf, git_dir);
146 }
147 strbuf_addch(&buf, '/');
148 if (buf.len >= PATH_MAX)
150 return bad_path;
151 memcpy(pathname, buf.buf, buf.len + 1);
152 strbuf_release(&buf);
154 len = strlen(pathname);
155 va_start(args, fmt);
157 len += vsnprintf(pathname + len, PATH_MAX - len, fmt, args);
158 va_end(args);
159 if (len >= PATH_MAX)
160 return bad_path;
161 return cleanup_path(pathname);
162}
163/* git_mkstemp() - create tmp file honoring TMPDIR variable */
165int git_mkstemp(char *path, size_t len, const char *template)
166{
167 const char *tmp;
168 size_t n;
169 tmp = getenv("TMPDIR");
171 if (!tmp)
172 tmp = "/tmp";
173 n = snprintf(path, len, "%s/%s", tmp, template);
174 if (len <= n) {
175 errno = ENAMETOOLONG;
176 return -1;
177 }
178 return mkstemp(path);
179}
180/* git_mkstemps() - create tmp file with suffix honoring TMPDIR variable. */
182int git_mkstemps(char *path, size_t len, const char *template, int suffix_len)
183{
184 const char *tmp;
185 size_t n;
186 tmp = getenv("TMPDIR");
188 if (!tmp)
189 tmp = "/tmp";
190 n = snprintf(path, len, "%s/%s", tmp, template);
191 if (len <= n) {
192 errno = ENAMETOOLONG;
193 return -1;
194 }
195 return mkstemps(path, suffix_len);
196}
197/* Adapted from libiberty's mkstemp.c. */
199#undef TMP_MAX
201#define TMP_MAX 16384
202int git_mkstemps_mode(char *pattern, int suffix_len, int mode)
204{
205 static const char letters[] =
206 "abcdefghijklmnopqrstuvwxyz"
207 "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
208 "0123456789";
209 static const int num_letters = 62;
210 uint64_t value;
211 struct timeval tv;
212 char *template;
213 size_t len;
214 int fd, count;
215 len = strlen(pattern);
217 if (len < 6 + suffix_len) {
219 errno = EINVAL;
220 return -1;
221 }
222 if (strncmp(&pattern[len - 6 - suffix_len], "XXXXXX", 6)) {
224 errno = EINVAL;
225 return -1;
226 }
227 /*
229 * Replace pattern's XXXXXX characters with randomness.
230 * Try TMP_MAX different filenames.
231 */
232 gettimeofday(&tv, NULL);
233 value = ((size_t)(tv.tv_usec << 16)) ^ tv.tv_sec ^ getpid();
234 template = &pattern[len - 6 - suffix_len];
235 for (count = 0; count < TMP_MAX; ++count) {
236 uint64_t v = value;
237 /* Fill in the random bits. */
238 template[0] = letters[v % num_letters]; v /= num_letters;
239 template[1] = letters[v % num_letters]; v /= num_letters;
240 template[2] = letters[v % num_letters]; v /= num_letters;
241 template[3] = letters[v % num_letters]; v /= num_letters;
242 template[4] = letters[v % num_letters]; v /= num_letters;
243 template[5] = letters[v % num_letters]; v /= num_letters;
244 fd = open(pattern, O_CREAT | O_EXCL | O_RDWR, mode);
246 if (fd > 0)
247 return fd;
248 /*
249 * Fatal error (EPERM, ENOSPC etc).
250 * It doesn't make sense to loop.
251 */
252 if (errno != EEXIST)
253 break;
254 /*
255 * This is a random value. It is only necessary that
256 * the next TMP_MAX values generated by adding 7777 to
257 * VALUE are different with (module 2^32).
258 */
259 value += 7777;
260 }
261 /* We return the null string if we can't find a unique file name. */
262 pattern[0] = '\0';
263 return -1;
264}
265int git_mkstemp_mode(char *pattern, int mode)
267{
268 /* mkstemp is just mkstemps with no suffix */
269 return git_mkstemps_mode(pattern, 0, mode);
270}
271int gitmkstemps(char *pattern, int suffix_len)
273{
274 return git_mkstemps_mode(pattern, suffix_len, 0600);
275}
276int validate_headref(const char *path)
278{
279 struct stat st;
280 char *buf, buffer[256];
281 unsigned char sha1[20];
282 int fd;
283 ssize_t len;
284 if (lstat(path, &st) < 0)
286 return -1;
287 /* Make sure it is a "refs/.." symlink */
289 if (S_ISLNK(st.st_mode)) {
290 len = readlink(path, buffer, sizeof(buffer)-1);
291 if (len >= 5 && !memcmp("refs/", buffer, 5))
292 return 0;
293 return -1;
294 }
295 /*
297 * Anything else, just open it and try to see if it is a symbolic ref.
298 */
299 fd = open(path, O_RDONLY);
300 if (fd < 0)
301 return -1;
302 len = read_in_full(fd, buffer, sizeof(buffer)-1);
303 close(fd);
304 /*
306 * Is it a symbolic ref?
307 */
308 if (len < 4)
309 return -1;
310 if (!memcmp("ref:", buffer, 4)) {
311 buf = buffer + 4;
312 len -= 4;
313 while (len && isspace(*buf))
314 buf++, len--;
315 if (len >= 5 && !memcmp("refs/", buf, 5))
316 return 0;
317 }
318 /*
320 * Is this a detached HEAD?
321 */
322 if (!get_sha1_hex(buffer, sha1))
323 return 0;
324 return -1;
326}
327static struct passwd *getpw_str(const char *username, size_t len)
329{
330 struct passwd *pw;
331 char *username_z = xmalloc(len + 1);
332 memcpy(username_z, username, len);
333 username_z[len] = '\0';
334 pw = getpwnam(username_z);
335 free(username_z);
336 return pw;
337}
338/*
340 * Return a string with ~ and ~user expanded via getpw*. If buf != NULL,
341 * then it is a newly allocated string. Returns NULL on getpw failure or
342 * if path is NULL.
343 */
344char *expand_user_path(const char *path)
345{
346 struct strbuf user_path = STRBUF_INIT;
347 const char *first_slash = strchrnul(path, '/');
348 const char *to_copy = path;
349 if (path == NULL)
351 goto return_null;
352 if (path[0] == '~') {
353 const char *username = path + 1;
354 size_t username_len = first_slash - username;
355 if (username_len == 0) {
356 const char *home = getenv("HOME");
357 if (!home)
358 goto return_null;
359 strbuf_add(&user_path, home, strlen(home));
360 } else {
361 struct passwd *pw = getpw_str(username, username_len);
362 if (!pw)
363 goto return_null;
364 strbuf_add(&user_path, pw->pw_dir, strlen(pw->pw_dir));
365 }
366 to_copy = first_slash;
367 }
368 strbuf_add(&user_path, to_copy, strlen(to_copy));
369 return strbuf_detach(&user_path, NULL);
370return_null:
371 strbuf_release(&user_path);
372 return NULL;
373}
374/*
376 * First, one directory to try is determined by the following algorithm.
377 *
378 * (0) If "strict" is given, the path is used as given and no DWIM is
379 * done. Otherwise:
380 * (1) "~/path" to mean path under the running user's home directory;
381 * (2) "~user/path" to mean path under named user's home directory;
382 * (3) "relative/path" to mean cwd relative directory; or
383 * (4) "/absolute/path" to mean absolute directory.
384 *
385 * Unless "strict" is given, we try access() for existence of "%s.git/.git",
386 * "%s/.git", "%s.git", "%s" in this order. The first one that exists is
387 * what we try.
388 *
389 * Second, we try chdir() to that. Upon failure, we return NULL.
390 *
391 * Then, we try if the current directory is a valid git repository.
392 * Upon failure, we return NULL.
393 *
394 * If all goes well, we return the directory we used to chdir() (but
395 * before ~user is expanded), avoiding getcwd() resolving symbolic
396 * links. User relative paths are also returned as they are given,
397 * except DWIM suffixing.
398 */
399char *enter_repo(char *path, int strict)
400{
401 static char used_path[PATH_MAX];
402 static char validated_path[PATH_MAX];
403 if (!path)
405 return NULL;
406 if (!strict) {
408 static const char *suffix[] = {
409 ".git/.git", "/.git", ".git", "", NULL,
410 };
411 int len = strlen(path);
412 int i;
413 while ((1 < len) && (path[len-1] == '/')) {
414 path[len-1] = 0;
415 len--;
416 }
417 if (PATH_MAX <= len)
418 return NULL;
419 if (path[0] == '~') {
420 char *newpath = expand_user_path(path);
421 if (!newpath || (PATH_MAX - 10 < strlen(newpath))) {
422 free(newpath);
423 return NULL;
424 }
425 /*
426 * Copy back into the static buffer. A pity
427 * since newpath was not bounded, but other
428 * branches of the if are limited by PATH_MAX
429 * anyway.
430 */
431 strcpy(used_path, newpath); free(newpath);
432 strcpy(validated_path, path);
433 path = used_path;
434 }
435 else if (PATH_MAX - 10 < len)
436 return NULL;
437 else {
438 path = strcpy(used_path, path);
439 strcpy(validated_path, path);
440 }
441 len = strlen(path);
442 for (i = 0; suffix[i]; i++) {
443 strcpy(path + len, suffix[i]);
444 if (!access(path, F_OK)) {
445 strcat(validated_path, suffix[i]);
446 break;
447 }
448 }
449 if (!suffix[i] || chdir(path))
450 return NULL;
451 path = validated_path;
452 }
453 else if (chdir(path))
454 return NULL;
455 if (access("objects", X_OK) == 0 && access("refs", X_OK) == 0 &&
457 validate_headref("HEAD") == 0) {
458 set_git_dir(".");
459 check_repository_format();
460 return path;
461 }
462 return NULL;
464}
465int set_shared_perm(const char *path, int mode)
467{
468 struct stat st;
469 int tweak, shared, orig_mode;
470 if (!shared_repository) {
472 if (mode)
473 return chmod(path, mode & ~S_IFMT);
474 return 0;
475 }
476 if (!mode) {
477 if (lstat(path, &st) < 0)
478 return -1;
479 mode = st.st_mode;
480 orig_mode = mode;
481 } else
482 orig_mode = 0;
483 if (shared_repository < 0)
484 shared = -shared_repository;
485 else
486 shared = shared_repository;
487 tweak = shared;
488 if (!(mode & S_IWUSR))
490 tweak &= ~0222;
491 if (mode & S_IXUSR)
492 /* Copy read bits to execute bits */
493 tweak |= (tweak & 0444) >> 2;
494 if (shared_repository < 0)
495 mode = (mode & ~0777) | tweak;
496 else
497 mode |= tweak;
498 if (S_ISDIR(mode)) {
500 /* Copy read bits to execute bits */
501 mode |= (shared & 0444) >> 2;
502 mode |= FORCE_DIR_SET_GID;
503 }
504 if (((shared_repository < 0
506 ? (orig_mode & (FORCE_DIR_SET_GID | 0777))
507 : (orig_mode & mode)) != mode) &&
508 chmod(path, (mode & ~S_IFMT)) < 0)
509 return -2;
510 return 0;
511}
512const char *make_relative_path(const char *abs, const char *base)
514{
515 static char buf[PATH_MAX + 1];
516 int i = 0, j = 0;
517 if (!base || !base[0])
519 return abs;
520 while (base[i]) {
521 if (is_dir_sep(base[i])) {
522 if (!is_dir_sep(abs[j]))
523 return abs;
524 while (is_dir_sep(base[i]))
525 i++;
526 while (is_dir_sep(abs[j]))
527 j++;
528 continue;
529 } else if (abs[j] != base[i]) {
530 return abs;
531 }
532 i++;
533 j++;
534 }
535 if (
536 /* "/foo" is a prefix of "/foo" */
537 abs[j] &&
538 /* "/foo" is not a prefix of "/foobar" */
539 !is_dir_sep(base[i-1]) && !is_dir_sep(abs[j])
540 )
541 return abs;
542 while (is_dir_sep(abs[j]))
543 j++;
544 if (!abs[j])
545 strcpy(buf, ".");
546 else
547 strcpy(buf, abs + j);
548 return buf;
549}
550/*
552 * It is okay if dst == src, but they should not overlap otherwise.
553 *
554 * Performs the following normalizations on src, storing the result in dst:
555 * - Ensures that components are separated by '/' (Windows only)
556 * - Squashes sequences of '/'.
557 * - Removes "." components.
558 * - Removes ".." components, and the components the precede them.
559 * Returns failure (non-zero) if a ".." component appears as first path
560 * component anytime during the normalization. Otherwise, returns success (0).
561 *
562 * Note that this function is purely textual. It does not follow symlinks,
563 * verify the existence of the path, or make any system calls.
564 */
565int normalize_path_copy(char *dst, const char *src)
566{
567 char *dst0;
568 if (has_dos_drive_prefix(src)) {
570 *dst++ = *src++;
571 *dst++ = *src++;
572 }
573 dst0 = dst;
574 if (is_dir_sep(*src)) {
576 *dst++ = '/';
577 while (is_dir_sep(*src))
578 src++;
579 }
580 for (;;) {
582 char c = *src;
583 /*
585 * A path component that begins with . could be
586 * special:
587 * (1) "." and ends -- ignore and terminate.
588 * (2) "./" -- ignore them, eat slash and continue.
589 * (3) ".." and ends -- strip one and terminate.
590 * (4) "../" -- strip one, eat slash and continue.
591 */
592 if (c == '.') {
593 if (!src[1]) {
594 /* (1) */
595 src++;
596 } else if (is_dir_sep(src[1])) {
597 /* (2) */
598 src += 2;
599 while (is_dir_sep(*src))
600 src++;
601 continue;
602 } else if (src[1] == '.') {
603 if (!src[2]) {
604 /* (3) */
605 src += 2;
606 goto up_one;
607 } else if (is_dir_sep(src[2])) {
608 /* (4) */
609 src += 3;
610 while (is_dir_sep(*src))
611 src++;
612 goto up_one;
613 }
614 }
615 }
616 /* copy up to the next '/', and eat all '/' */
618 while ((c = *src++) != '\0' && !is_dir_sep(c))
619 *dst++ = c;
620 if (is_dir_sep(c)) {
621 *dst++ = '/';
622 while (is_dir_sep(c))
623 c = *src++;
624 src--;
625 } else if (!c)
626 break;
627 continue;
628 up_one:
630 /*
631 * dst0..dst is prefix portion, and dst[-1] is '/';
632 * go up one level.
633 */
634 dst--; /* go to trailing '/' */
635 if (dst <= dst0)
636 return -1;
637 /* Windows: dst[-1] cannot be backslash anymore */
638 while (dst0 < dst && dst[-1] != '/')
639 dst--;
640 }
641 *dst = '\0';
642 return 0;
643}
644/*
646 * path = Canonical absolute path
647 * prefix_list = Colon-separated list of absolute paths
648 *
649 * Determines, for each path in prefix_list, whether the "prefix" really
650 * is an ancestor directory of path. Returns the length of the longest
651 * ancestor directory, excluding any trailing slashes, or -1 if no prefix
652 * is an ancestor. (Note that this means 0 is returned if prefix_list is
653 * "/".) "/foo" is not considered an ancestor of "/foobar". Directories
654 * are not considered to be their own ancestors. path must be in a
655 * canonical form: empty components, or "." or ".." components are not
656 * allowed. prefix_list may be null, which is like "".
657 */
658int longest_ancestor_length(const char *path, const char *prefix_list)
659{
660 char buf[PATH_MAX+1];
661 const char *ceil, *colon;
662 int len, max_len = -1;
663 if (prefix_list == NULL || !strcmp(path, "/"))
665 return -1;
666 for (colon = ceil = prefix_list; *colon; ceil = colon+1) {
668 for (colon = ceil; *colon && *colon != PATH_SEP; colon++);
669 len = colon - ceil;
670 if (len == 0 || len > PATH_MAX || !is_absolute_path(ceil))
671 continue;
672 strlcpy(buf, ceil, len+1);
673 if (normalize_path_copy(buf, buf) < 0)
674 continue;
675 len = strlen(buf);
676 if (len > 0 && buf[len-1] == '/')
677 buf[--len] = '\0';
678 if (!strncmp(path, buf, len) &&
680 path[len] == '/' &&
681 len > max_len) {
682 max_len = len;
683 }
684 }
685 return max_len;
687}
688/* strip arbitrary amount of directory separators at end of path */
690static inline int chomp_trailing_dir_sep(const char *path, int len)
691{
692 while (len && is_dir_sep(path[len - 1]))
693 len--;
694 return len;
695}
696/*
698 * If path ends with suffix (complete path components), returns the
699 * part before suffix (sans trailing directory separators).
700 * Otherwise returns NULL.
701 */
702char *strip_path_suffix(const char *path, const char *suffix)
703{
704 int path_len = strlen(path), suffix_len = strlen(suffix);
705 while (suffix_len) {
707 if (!path_len)
708 return NULL;
709 if (is_dir_sep(path[path_len - 1])) {
711 if (!is_dir_sep(suffix[suffix_len - 1]))
712 return NULL;
713 path_len = chomp_trailing_dir_sep(path, path_len);
714 suffix_len = chomp_trailing_dir_sep(suffix, suffix_len);
715 }
716 else if (path[--path_len] != suffix[--suffix_len])
717 return NULL;
718 }
719 if (path_len && !is_dir_sep(path[path_len - 1]))
721 return NULL;
722 return xstrndup(path, chomp_trailing_dir_sep(path, path_len));
723}
724int daemon_avoid_alias(const char *p)
726{
727 int sl, ndot;
728 /*
730 * This resurrects the belts and suspenders paranoia check by HPA
731 * done in <435560F7.4080006@zytor.com> thread, now enter_repo()
732 * does not do getcwd() based path canonicalization.
733 *
734 * sl becomes true immediately after seeing '/' and continues to
735 * be true as long as dots continue after that without intervening
736 * non-dot character.
737 */
738 if (!p || (*p != '/' && *p != '~'))
739 return -1;
740 sl = 1; ndot = 0;
741 p++;
742 while (1) {
744 char ch = *p++;
745 if (sl) {
746 if (ch == '.')
747 ndot++;
748 else if (ch == '/') {
749 if (ndot < 3)
750 /* reject //, /./ and /../ */
751 return -1;
752 ndot = 0;
753 }
754 else if (ch == 0) {
755 if (0 < ndot && ndot < 3)
756 /* reject /.$ and /..$ */
757 return -1;
758 return 0;
759 }
760 else
761 sl = ndot = 0;
762 }
763 else if (ch == 0)
764 return 0;
765 else if (ch == '/') {
766 sl = 1;
767 ndot = 0;
768 }
769 }
770}
771int offset_1st_component(const char *path)
773{
774 if (has_dos_drive_prefix(path))
775 return 2 + is_dir_sep(path[2]);
776 return is_dir_sep(path[0]);
777}