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 strbuf_add(&user_path, home, strlen(home));
358 } else {
359 struct passwd *pw = getpw_str(username, username_len);
360 if (!pw)
361 goto return_null;
362 strbuf_add(&user_path, pw->pw_dir, strlen(pw->pw_dir));
363 }
364 to_copy = first_slash;
365 }
366 strbuf_add(&user_path, to_copy, strlen(to_copy));
367 return strbuf_detach(&user_path, NULL);
368return_null:
369 strbuf_release(&user_path);
370 return NULL;
371}
372/*
374 * First, one directory to try is determined by the following algorithm.
375 *
376 * (0) If "strict" is given, the path is used as given and no DWIM is
377 * done. Otherwise:
378 * (1) "~/path" to mean path under the running user's home directory;
379 * (2) "~user/path" to mean path under named user's home directory;
380 * (3) "relative/path" to mean cwd relative directory; or
381 * (4) "/absolute/path" to mean absolute directory.
382 *
383 * Unless "strict" is given, we try access() for existence of "%s.git/.git",
384 * "%s/.git", "%s.git", "%s" in this order. The first one that exists is
385 * what we try.
386 *
387 * Second, we try chdir() to that. Upon failure, we return NULL.
388 *
389 * Then, we try if the current directory is a valid git repository.
390 * Upon failure, we return NULL.
391 *
392 * If all goes well, we return the directory we used to chdir() (but
393 * before ~user is expanded), avoiding getcwd() resolving symbolic
394 * links. User relative paths are also returned as they are given,
395 * except DWIM suffixing.
396 */
397char *enter_repo(char *path, int strict)
398{
399 static char used_path[PATH_MAX];
400 static char validated_path[PATH_MAX];
401 if (!path)
403 return NULL;
404 if (!strict) {
406 static const char *suffix[] = {
407 ".git/.git", "/.git", ".git", "", NULL,
408 };
409 int len = strlen(path);
410 int i;
411 while ((1 < len) && (path[len-1] == '/')) {
412 path[len-1] = 0;
413 len--;
414 }
415 if (PATH_MAX <= len)
416 return NULL;
417 if (path[0] == '~') {
418 char *newpath = expand_user_path(path);
419 if (!newpath || (PATH_MAX - 10 < strlen(newpath))) {
420 free(newpath);
421 return NULL;
422 }
423 /*
424 * Copy back into the static buffer. A pity
425 * since newpath was not bounded, but other
426 * branches of the if are limited by PATH_MAX
427 * anyway.
428 */
429 strcpy(used_path, newpath); free(newpath);
430 strcpy(validated_path, path);
431 path = used_path;
432 }
433 else if (PATH_MAX - 10 < len)
434 return NULL;
435 else {
436 path = strcpy(used_path, path);
437 strcpy(validated_path, path);
438 }
439 len = strlen(path);
440 for (i = 0; suffix[i]; i++) {
441 strcpy(path + len, suffix[i]);
442 if (!access(path, F_OK)) {
443 strcat(validated_path, suffix[i]);
444 break;
445 }
446 }
447 if (!suffix[i] || chdir(path))
448 return NULL;
449 path = validated_path;
450 }
451 else if (chdir(path))
452 return NULL;
453 if (access("objects", X_OK) == 0 && access("refs", X_OK) == 0 &&
455 validate_headref("HEAD") == 0) {
456 set_git_dir(".");
457 check_repository_format();
458 return path;
459 }
460 return NULL;
462}
463int set_shared_perm(const char *path, int mode)
465{
466 struct stat st;
467 int tweak, shared, orig_mode;
468 if (!shared_repository) {
470 if (mode)
471 return chmod(path, mode & ~S_IFMT);
472 return 0;
473 }
474 if (!mode) {
475 if (lstat(path, &st) < 0)
476 return -1;
477 mode = st.st_mode;
478 orig_mode = mode;
479 } else
480 orig_mode = 0;
481 if (shared_repository < 0)
482 shared = -shared_repository;
483 else
484 shared = shared_repository;
485 tweak = shared;
486 if (!(mode & S_IWUSR))
488 tweak &= ~0222;
489 if (mode & S_IXUSR)
490 /* Copy read bits to execute bits */
491 tweak |= (tweak & 0444) >> 2;
492 if (shared_repository < 0)
493 mode = (mode & ~0777) | tweak;
494 else
495 mode |= tweak;
496 if (S_ISDIR(mode)) {
498 /* Copy read bits to execute bits */
499 mode |= (shared & 0444) >> 2;
500 mode |= FORCE_DIR_SET_GID;
501 }
502 if (((shared_repository < 0
504 ? (orig_mode & (FORCE_DIR_SET_GID | 0777))
505 : (orig_mode & mode)) != mode) &&
506 chmod(path, (mode & ~S_IFMT)) < 0)
507 return -2;
508 return 0;
509}
510const char *make_relative_path(const char *abs, const char *base)
512{
513 static char buf[PATH_MAX + 1];
514 int i = 0, j = 0;
515 if (!base || !base[0])
517 return abs;
518 while (base[i]) {
519 if (is_dir_sep(base[i])) {
520 if (!is_dir_sep(abs[j]))
521 return abs;
522 while (is_dir_sep(base[i]))
523 i++;
524 while (is_dir_sep(abs[j]))
525 j++;
526 continue;
527 } else if (abs[j] != base[i]) {
528 return abs;
529 }
530 i++;
531 j++;
532 }
533 if (
534 /* "/foo" is a prefix of "/foo" */
535 abs[j] &&
536 /* "/foo" is not a prefix of "/foobar" */
537 !is_dir_sep(base[i-1]) && !is_dir_sep(abs[j])
538 )
539 return abs;
540 while (is_dir_sep(abs[j]))
541 j++;
542 if (!abs[j])
543 strcpy(buf, ".");
544 else
545 strcpy(buf, abs + j);
546 return buf;
547}
548/*
550 * It is okay if dst == src, but they should not overlap otherwise.
551 *
552 * Performs the following normalizations on src, storing the result in dst:
553 * - Ensures that components are separated by '/' (Windows only)
554 * - Squashes sequences of '/'.
555 * - Removes "." components.
556 * - Removes ".." components, and the components the precede them.
557 * Returns failure (non-zero) if a ".." component appears as first path
558 * component anytime during the normalization. Otherwise, returns success (0).
559 *
560 * Note that this function is purely textual. It does not follow symlinks,
561 * verify the existence of the path, or make any system calls.
562 */
563int normalize_path_copy(char *dst, const char *src)
564{
565 char *dst0;
566 if (has_dos_drive_prefix(src)) {
568 *dst++ = *src++;
569 *dst++ = *src++;
570 }
571 dst0 = dst;
572 if (is_dir_sep(*src)) {
574 *dst++ = '/';
575 while (is_dir_sep(*src))
576 src++;
577 }
578 for (;;) {
580 char c = *src;
581 /*
583 * A path component that begins with . could be
584 * special:
585 * (1) "." and ends -- ignore and terminate.
586 * (2) "./" -- ignore them, eat slash and continue.
587 * (3) ".." and ends -- strip one and terminate.
588 * (4) "../" -- strip one, eat slash and continue.
589 */
590 if (c == '.') {
591 if (!src[1]) {
592 /* (1) */
593 src++;
594 } else if (is_dir_sep(src[1])) {
595 /* (2) */
596 src += 2;
597 while (is_dir_sep(*src))
598 src++;
599 continue;
600 } else if (src[1] == '.') {
601 if (!src[2]) {
602 /* (3) */
603 src += 2;
604 goto up_one;
605 } else if (is_dir_sep(src[2])) {
606 /* (4) */
607 src += 3;
608 while (is_dir_sep(*src))
609 src++;
610 goto up_one;
611 }
612 }
613 }
614 /* copy up to the next '/', and eat all '/' */
616 while ((c = *src++) != '\0' && !is_dir_sep(c))
617 *dst++ = c;
618 if (is_dir_sep(c)) {
619 *dst++ = '/';
620 while (is_dir_sep(c))
621 c = *src++;
622 src--;
623 } else if (!c)
624 break;
625 continue;
626 up_one:
628 /*
629 * dst0..dst is prefix portion, and dst[-1] is '/';
630 * go up one level.
631 */
632 dst--; /* go to trailing '/' */
633 if (dst <= dst0)
634 return -1;
635 /* Windows: dst[-1] cannot be backslash anymore */
636 while (dst0 < dst && dst[-1] != '/')
637 dst--;
638 }
639 *dst = '\0';
640 return 0;
641}
642/*
644 * path = Canonical absolute path
645 * prefix_list = Colon-separated list of absolute paths
646 *
647 * Determines, for each path in prefix_list, whether the "prefix" really
648 * is an ancestor directory of path. Returns the length of the longest
649 * ancestor directory, excluding any trailing slashes, or -1 if no prefix
650 * is an ancestor. (Note that this means 0 is returned if prefix_list is
651 * "/".) "/foo" is not considered an ancestor of "/foobar". Directories
652 * are not considered to be their own ancestors. path must be in a
653 * canonical form: empty components, or "." or ".." components are not
654 * allowed. prefix_list may be null, which is like "".
655 */
656int longest_ancestor_length(const char *path, const char *prefix_list)
657{
658 char buf[PATH_MAX+1];
659 const char *ceil, *colon;
660 int len, max_len = -1;
661 if (prefix_list == NULL || !strcmp(path, "/"))
663 return -1;
664 for (colon = ceil = prefix_list; *colon; ceil = colon+1) {
666 for (colon = ceil; *colon && *colon != PATH_SEP; colon++);
667 len = colon - ceil;
668 if (len == 0 || len > PATH_MAX || !is_absolute_path(ceil))
669 continue;
670 strlcpy(buf, ceil, len+1);
671 if (normalize_path_copy(buf, buf) < 0)
672 continue;
673 len = strlen(buf);
674 if (len > 0 && buf[len-1] == '/')
675 buf[--len] = '\0';
676 if (!strncmp(path, buf, len) &&
678 path[len] == '/' &&
679 len > max_len) {
680 max_len = len;
681 }
682 }
683 return max_len;
685}
686/* strip arbitrary amount of directory separators at end of path */
688static inline int chomp_trailing_dir_sep(const char *path, int len)
689{
690 while (len && is_dir_sep(path[len - 1]))
691 len--;
692 return len;
693}
694/*
696 * If path ends with suffix (complete path components), returns the
697 * part before suffix (sans trailing directory separators).
698 * Otherwise returns NULL.
699 */
700char *strip_path_suffix(const char *path, const char *suffix)
701{
702 int path_len = strlen(path), suffix_len = strlen(suffix);
703 while (suffix_len) {
705 if (!path_len)
706 return NULL;
707 if (is_dir_sep(path[path_len - 1])) {
709 if (!is_dir_sep(suffix[suffix_len - 1]))
710 return NULL;
711 path_len = chomp_trailing_dir_sep(path, path_len);
712 suffix_len = chomp_trailing_dir_sep(suffix, suffix_len);
713 }
714 else if (path[--path_len] != suffix[--suffix_len])
715 return NULL;
716 }
717 if (path_len && !is_dir_sep(path[path_len - 1]))
719 return NULL;
720 return xstrndup(path, chomp_trailing_dir_sep(path, path_len));
721}
722int daemon_avoid_alias(const char *p)
724{
725 int sl, ndot;
726 /*
728 * This resurrects the belts and suspenders paranoia check by HPA
729 * done in <435560F7.4080006@zytor.com> thread, now enter_repo()
730 * does not do getcwd() based path canonicalization.
731 *
732 * sl becomes true immediately after seeing '/' and continues to
733 * be true as long as dots continue after that without intervening
734 * non-dot character.
735 */
736 if (!p || (*p != '/' && *p != '~'))
737 return -1;
738 sl = 1; ndot = 0;
739 p++;
740 while (1) {
742 char ch = *p++;
743 if (sl) {
744 if (ch == '.')
745 ndot++;
746 else if (ch == '/') {
747 if (ndot < 3)
748 /* reject //, /./ and /../ */
749 return -1;
750 ndot = 0;
751 }
752 else if (ch == 0) {
753 if (0 < ndot && ndot < 3)
754 /* reject /.$ and /..$ */
755 return -1;
756 return 0;
757 }
758 else
759 sl = ndot = 0;
760 }
761 else if (ch == 0)
762 return 0;
763 else if (ch == '/') {
764 sl = 1;
765 ndot = 0;
766 }
767 }
768}
769int offset_1st_component(const char *path)
771{
772 if (has_dos_drive_prefix(path))
773 return 2 + is_dir_sep(path[2]);
774 return is_dir_sep(path[0]);
775}