gitk: Second try to work around the command line limit on Windows
[git/dscho.git] / path.c
blobb4c8d917229a4187f36a76f43603fc036e65632e
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.
6 * It's obviously not thread-safe. Sue me. But it's quite
7 * useful for doing things like
9 * f = open(mkpath("%s/%s.git", base, name), O_RDONLY);
11 * which is what it's designed for.
13 #include "cache.h"
14 #include "strbuf.h"
16 static char bad_path[] = "/bad-path/";
18 static char *get_pathname(void)
20 static char pathname_array[4][PATH_MAX];
21 static int index;
22 return pathname_array[3 & ++index];
25 static char *cleanup_path(char *path)
27 /* Clean it up */
28 if (!memcmp(path, "./", 2)) {
29 path += 2;
30 while (*path == '/')
31 path++;
33 return path;
36 char *mksnpath(char *buf, size_t n, const char *fmt, ...)
38 va_list args;
39 unsigned len;
41 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;
48 return cleanup_path(buf);
51 static char *git_vsnpath(char *buf, size_t n, const char *fmt, va_list args)
53 const char *git_dir = get_git_dir();
54 size_t len;
56 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);
66 bad:
67 strlcpy(buf, bad_path, n);
68 return buf;
71 char *git_snpath(char *buf, size_t n, const char *fmt, ...)
73 va_list args;
74 va_start(args, fmt);
75 (void)git_vsnpath(buf, n, fmt, args);
76 va_end(args);
77 return buf;
80 char *git_pathdup(const char *fmt, ...)
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);
90 char *mkpath(const char *fmt, ...)
92 va_list args;
93 unsigned len;
94 char *pathname = get_pathname();
96 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);
104 char *git_path(const char *fmt, ...)
106 const char *git_dir = get_git_dir();
107 char *pathname = get_pathname();
108 va_list args;
109 unsigned len;
111 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);
126 /* git_mkstemp() - create tmp file honoring TMPDIR variable */
127 int git_mkstemp(char *path, size_t len, const char *template)
129 const char *tmp;
130 size_t n;
132 tmp = getenv("TMPDIR");
133 if (!tmp)
134 tmp = "/tmp";
135 n = snprintf(path, len, "%s/%s", tmp, template);
136 if (len <= n) {
137 errno = ENAMETOOLONG;
138 return -1;
140 return mkstemp(path);
143 /* git_mkstemps() - create tmp file with suffix honoring TMPDIR variable. */
144 int git_mkstemps(char *path, size_t len, const char *template, int suffix_len)
146 const char *tmp;
147 size_t n;
149 tmp = getenv("TMPDIR");
150 if (!tmp)
151 tmp = "/tmp";
152 n = snprintf(path, len, "%s/%s", tmp, template);
153 if (len <= n) {
154 errno = ENAMETOOLONG;
155 return -1;
157 return mkstemps(path, suffix_len);
160 /* Adapted from libiberty's mkstemp.c. */
162 #undef TMP_MAX
163 #define TMP_MAX 16384
165 int git_mkstemps_mode(char *pattern, int suffix_len, int mode)
167 static const char letters[] =
168 "abcdefghijklmnopqrstuvwxyz"
169 "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
170 "0123456789";
171 static const int num_letters = 62;
172 uint64_t value;
173 struct timeval tv;
174 char *template;
175 size_t len;
176 int fd, count;
178 len = strlen(pattern);
180 if (len < 6 + suffix_len) {
181 errno = EINVAL;
182 return -1;
185 if (strncmp(&pattern[len - 6 - suffix_len], "XXXXXX", 6)) {
186 errno = EINVAL;
187 return -1;
191 * Replace pattern's XXXXXX characters with randomness.
192 * Try TMP_MAX different filenames.
194 gettimeofday(&tv, NULL);
195 value = ((size_t)(tv.tv_usec << 16)) ^ tv.tv_sec ^ getpid();
196 template = &pattern[len - 6 - suffix_len];
197 for (count = 0; count < TMP_MAX; ++count) {
198 uint64_t v = value;
199 /* Fill in the random bits. */
200 template[0] = letters[v % num_letters]; v /= num_letters;
201 template[1] = letters[v % num_letters]; v /= num_letters;
202 template[2] = letters[v % num_letters]; v /= num_letters;
203 template[3] = letters[v % num_letters]; v /= num_letters;
204 template[4] = letters[v % num_letters]; v /= num_letters;
205 template[5] = letters[v % num_letters]; v /= num_letters;
207 fd = open(pattern, O_CREAT | O_EXCL | O_RDWR, mode);
208 if (fd > 0)
209 return fd;
211 * Fatal error (EPERM, ENOSPC etc).
212 * It doesn't make sense to loop.
214 if (errno != EEXIST)
215 break;
217 * This is a random value. It is only necessary that
218 * the next TMP_MAX values generated by adding 7777 to
219 * VALUE are different with (module 2^32).
221 value += 7777;
223 /* We return the null string if we can't find a unique file name. */
224 pattern[0] = '\0';
225 return -1;
228 int git_mkstemp_mode(char *pattern, int mode)
230 /* mkstemp is just mkstemps with no suffix */
231 return git_mkstemps_mode(pattern, 0, mode);
234 int gitmkstemps(char *pattern, int suffix_len)
236 return git_mkstemps_mode(pattern, suffix_len, 0600);
239 int validate_headref(const char *path)
241 struct stat st;
242 char *buf, buffer[256];
243 unsigned char sha1[20];
244 int fd;
245 ssize_t len;
247 if (lstat(path, &st) < 0)
248 return -1;
250 /* Make sure it is a "refs/.." symlink */
251 if (S_ISLNK(st.st_mode)) {
252 len = readlink(path, buffer, sizeof(buffer)-1);
253 if (len >= 5 && !memcmp("refs/", buffer, 5))
254 return 0;
255 return -1;
259 * Anything else, just open it and try to see if it is a symbolic ref.
261 fd = open(path, O_RDONLY);
262 if (fd < 0)
263 return -1;
264 len = read_in_full(fd, buffer, sizeof(buffer)-1);
265 close(fd);
268 * Is it a symbolic ref?
270 if (len < 4)
271 return -1;
272 if (!memcmp("ref:", buffer, 4)) {
273 buf = buffer + 4;
274 len -= 4;
275 while (len && isspace(*buf))
276 buf++, len--;
277 if (len >= 5 && !memcmp("refs/", buf, 5))
278 return 0;
282 * Is this a detached HEAD?
284 if (!get_sha1_hex(buffer, sha1))
285 return 0;
287 return -1;
290 static struct passwd *getpw_str(const char *username, size_t len)
292 struct passwd *pw;
293 char *username_z = xmalloc(len + 1);
294 memcpy(username_z, username, len);
295 username_z[len] = '\0';
296 pw = getpwnam(username_z);
297 free(username_z);
298 return pw;
302 * Return a string with ~ and ~user expanded via getpw*. If buf != NULL,
303 * then it is a newly allocated string. Returns NULL on getpw failure or
304 * if path is NULL.
306 char *expand_user_path(const char *path)
308 struct strbuf user_path = STRBUF_INIT;
309 const char *first_slash = strchrnul(path, '/');
310 const char *to_copy = path;
312 if (path == NULL)
313 goto return_null;
314 if (path[0] == '~') {
315 const char *username = path + 1;
316 size_t username_len = first_slash - username;
317 if (username_len == 0) {
318 const char *home = getenv("HOME");
319 strbuf_add(&user_path, home, strlen(home));
320 } else {
321 struct passwd *pw = getpw_str(username, username_len);
322 if (!pw)
323 goto return_null;
324 strbuf_add(&user_path, pw->pw_dir, strlen(pw->pw_dir));
326 to_copy = first_slash;
328 strbuf_add(&user_path, to_copy, strlen(to_copy));
329 return strbuf_detach(&user_path, NULL);
330 return_null:
331 strbuf_release(&user_path);
332 return NULL;
336 * First, one directory to try is determined by the following algorithm.
338 * (0) If "strict" is given, the path is used as given and no DWIM is
339 * done. Otherwise:
340 * (1) "~/path" to mean path under the running user's home directory;
341 * (2) "~user/path" to mean path under named user's home directory;
342 * (3) "relative/path" to mean cwd relative directory; or
343 * (4) "/absolute/path" to mean absolute directory.
345 * Unless "strict" is given, we try access() for existence of "%s.git/.git",
346 * "%s/.git", "%s.git", "%s" in this order. The first one that exists is
347 * what we try.
349 * Second, we try chdir() to that. Upon failure, we return NULL.
351 * Then, we try if the current directory is a valid git repository.
352 * Upon failure, we return NULL.
354 * If all goes well, we return the directory we used to chdir() (but
355 * before ~user is expanded), avoiding getcwd() resolving symbolic
356 * links. User relative paths are also returned as they are given,
357 * except DWIM suffixing.
359 char *enter_repo(char *path, int strict)
361 static char used_path[PATH_MAX];
362 static char validated_path[PATH_MAX];
364 if (!path)
365 return NULL;
367 if (!strict) {
368 static const char *suffix[] = {
369 ".git/.git", "/.git", ".git", "", NULL,
371 int len = strlen(path);
372 int i;
373 while ((1 < len) && (path[len-1] == '/')) {
374 path[len-1] = 0;
375 len--;
377 if (PATH_MAX <= len)
378 return NULL;
379 if (path[0] == '~') {
380 char *newpath = expand_user_path(path);
381 if (!newpath || (PATH_MAX - 10 < strlen(newpath))) {
382 free(newpath);
383 return NULL;
386 * Copy back into the static buffer. A pity
387 * since newpath was not bounded, but other
388 * branches of the if are limited by PATH_MAX
389 * anyway.
391 strcpy(used_path, newpath); free(newpath);
392 strcpy(validated_path, path);
393 path = used_path;
395 else if (PATH_MAX - 10 < len)
396 return NULL;
397 else {
398 path = strcpy(used_path, path);
399 strcpy(validated_path, path);
401 len = strlen(path);
402 for (i = 0; suffix[i]; i++) {
403 strcpy(path + len, suffix[i]);
404 if (!access(path, F_OK)) {
405 strcat(validated_path, suffix[i]);
406 break;
409 if (!suffix[i] || chdir(path))
410 return NULL;
411 path = validated_path;
413 else if (chdir(path))
414 return NULL;
416 if (access("objects", X_OK) == 0 && access("refs", X_OK) == 0 &&
417 validate_headref("HEAD") == 0) {
418 set_git_dir(".");
419 check_repository_format();
420 return path;
423 return NULL;
426 int set_shared_perm(const char *path, int mode)
428 struct stat st;
429 int tweak, shared, orig_mode;
431 if (!shared_repository) {
432 if (mode)
433 return chmod(path, mode & ~S_IFMT);
434 return 0;
436 if (!mode) {
437 if (lstat(path, &st) < 0)
438 return -1;
439 mode = st.st_mode;
440 orig_mode = mode;
441 } else
442 orig_mode = 0;
443 if (shared_repository < 0)
444 shared = -shared_repository;
445 else
446 shared = shared_repository;
447 tweak = shared;
449 if (!(mode & S_IWUSR))
450 tweak &= ~0222;
451 if (mode & S_IXUSR)
452 /* Copy read bits to execute bits */
453 tweak |= (tweak & 0444) >> 2;
454 if (shared_repository < 0)
455 mode = (mode & ~0777) | tweak;
456 else
457 mode |= tweak;
459 if (S_ISDIR(mode)) {
460 /* Copy read bits to execute bits */
461 mode |= (shared & 0444) >> 2;
462 mode |= FORCE_DIR_SET_GID;
465 if (((shared_repository < 0
466 ? (orig_mode & (FORCE_DIR_SET_GID | 0777))
467 : (orig_mode & mode)) != mode) &&
468 chmod(path, (mode & ~S_IFMT)) < 0)
469 return -2;
470 return 0;
473 const char *make_relative_path(const char *abs, const char *base)
475 static char buf[PATH_MAX + 1];
476 int i = 0, j = 0;
478 if (!base || !base[0])
479 return abs;
480 while (base[i]) {
481 if (is_dir_sep(base[i])) {
482 if (!is_dir_sep(abs[j]))
483 return abs;
484 while (is_dir_sep(base[i]))
485 i++;
486 while (is_dir_sep(abs[j]))
487 j++;
488 continue;
489 } else if (abs[j] != base[i]) {
490 return abs;
492 i++;
493 j++;
495 if (
496 /* "/foo" is a prefix of "/foo" */
497 abs[j] &&
498 /* "/foo" is not a prefix of "/foobar" */
499 !is_dir_sep(base[i-1]) && !is_dir_sep(abs[j])
501 return abs;
502 while (is_dir_sep(abs[j]))
503 j++;
504 if (!abs[j])
505 strcpy(buf, ".");
506 else
507 strcpy(buf, abs + j);
508 return buf;
512 * It is okay if dst == src, but they should not overlap otherwise.
514 * Performs the following normalizations on src, storing the result in dst:
515 * - Ensures that components are separated by '/' (Windows only)
516 * - Squashes sequences of '/'.
517 * - Removes "." components.
518 * - Removes ".." components, and the components the precede them.
519 * Returns failure (non-zero) if a ".." component appears as first path
520 * component anytime during the normalization. Otherwise, returns success (0).
522 * Note that this function is purely textual. It does not follow symlinks,
523 * verify the existence of the path, or make any system calls.
525 int normalize_path_copy(char *dst, const char *src)
527 char *dst0;
529 if (has_dos_drive_prefix(src)) {
530 *dst++ = *src++;
531 *dst++ = *src++;
533 dst0 = dst;
535 if (is_dir_sep(*src)) {
536 *dst++ = '/';
537 while (is_dir_sep(*src))
538 src++;
541 for (;;) {
542 char c = *src;
545 * A path component that begins with . could be
546 * special:
547 * (1) "." and ends -- ignore and terminate.
548 * (2) "./" -- ignore them, eat slash and continue.
549 * (3) ".." and ends -- strip one and terminate.
550 * (4) "../" -- strip one, eat slash and continue.
552 if (c == '.') {
553 if (!src[1]) {
554 /* (1) */
555 src++;
556 } else if (is_dir_sep(src[1])) {
557 /* (2) */
558 src += 2;
559 while (is_dir_sep(*src))
560 src++;
561 continue;
562 } else if (src[1] == '.') {
563 if (!src[2]) {
564 /* (3) */
565 src += 2;
566 goto up_one;
567 } else if (is_dir_sep(src[2])) {
568 /* (4) */
569 src += 3;
570 while (is_dir_sep(*src))
571 src++;
572 goto up_one;
577 /* copy up to the next '/', and eat all '/' */
578 while ((c = *src++) != '\0' && !is_dir_sep(c))
579 *dst++ = c;
580 if (is_dir_sep(c)) {
581 *dst++ = '/';
582 while (is_dir_sep(c))
583 c = *src++;
584 src--;
585 } else if (!c)
586 break;
587 continue;
589 up_one:
591 * dst0..dst is prefix portion, and dst[-1] is '/';
592 * go up one level.
594 dst--; /* go to trailing '/' */
595 if (dst <= dst0)
596 return -1;
597 /* Windows: dst[-1] cannot be backslash anymore */
598 while (dst0 < dst && dst[-1] != '/')
599 dst--;
601 *dst = '\0';
602 return 0;
606 * path = Canonical absolute path
607 * prefix_list = Colon-separated list of absolute paths
609 * Determines, for each path in prefix_list, whether the "prefix" really
610 * is an ancestor directory of path. Returns the length of the longest
611 * ancestor directory, excluding any trailing slashes, or -1 if no prefix
612 * is an ancestor. (Note that this means 0 is returned if prefix_list is
613 * "/".) "/foo" is not considered an ancestor of "/foobar". Directories
614 * are not considered to be their own ancestors. path must be in a
615 * canonical form: empty components, or "." or ".." components are not
616 * allowed. prefix_list may be null, which is like "".
618 int longest_ancestor_length(const char *path, const char *prefix_list)
620 char buf[PATH_MAX+1];
621 const char *ceil, *colon;
622 int len, max_len = -1;
624 if (prefix_list == NULL || !strcmp(path, "/"))
625 return -1;
627 for (colon = ceil = prefix_list; *colon; ceil = colon+1) {
628 for (colon = ceil; *colon && *colon != PATH_SEP; colon++);
629 len = colon - ceil;
630 if (len == 0 || len > PATH_MAX || !is_absolute_path(ceil))
631 continue;
632 strlcpy(buf, ceil, len+1);
633 if (normalize_path_copy(buf, buf) < 0)
634 continue;
635 len = strlen(buf);
636 if (len > 0 && buf[len-1] == '/')
637 buf[--len] = '\0';
639 if (!strncmp(path, buf, len) &&
640 path[len] == '/' &&
641 len > max_len) {
642 max_len = len;
646 return max_len;
649 /* strip arbitrary amount of directory separators at end of path */
650 static inline int chomp_trailing_dir_sep(const char *path, int len)
652 while (len && is_dir_sep(path[len - 1]))
653 len--;
654 return len;
658 * If path ends with suffix (complete path components), returns the
659 * part before suffix (sans trailing directory separators).
660 * Otherwise returns NULL.
662 char *strip_path_suffix(const char *path, const char *suffix)
664 int path_len = strlen(path), suffix_len = strlen(suffix);
666 while (suffix_len) {
667 if (!path_len)
668 return NULL;
670 if (is_dir_sep(path[path_len - 1])) {
671 if (!is_dir_sep(suffix[suffix_len - 1]))
672 return NULL;
673 path_len = chomp_trailing_dir_sep(path, path_len);
674 suffix_len = chomp_trailing_dir_sep(suffix, suffix_len);
676 else if (path[--path_len] != suffix[--suffix_len])
677 return NULL;
680 if (path_len && !is_dir_sep(path[path_len - 1]))
681 return NULL;
682 return xstrndup(path, chomp_trailing_dir_sep(path, path_len));
685 int daemon_avoid_alias(const char *p)
687 int sl, ndot;
690 * This resurrects the belts and suspenders paranoia check by HPA
691 * done in <435560F7.4080006@zytor.com> thread, now enter_repo()
692 * does not do getcwd() based path canonicalization.
694 * sl becomes true immediately after seeing '/' and continues to
695 * be true as long as dots continue after that without intervening
696 * non-dot character.
698 if (!p || (*p != '/' && *p != '~'))
699 return -1;
700 sl = 1; ndot = 0;
701 p++;
703 while (1) {
704 char ch = *p++;
705 if (sl) {
706 if (ch == '.')
707 ndot++;
708 else if (ch == '/') {
709 if (ndot < 3)
710 /* reject //, /./ and /../ */
711 return -1;
712 ndot = 0;
714 else if (ch == 0) {
715 if (0 < ndot && ndot < 3)
716 /* reject /.$ and /..$ */
717 return -1;
718 return 0;
720 else
721 sl = ndot = 0;
723 else if (ch == 0)
724 return 0;
725 else if (ch == '/') {
726 sl = 1;
727 ndot = 0;
732 int offset_1st_component(const char *path)
734 if (has_dos_drive_prefix(path))
735 return 2 + is_dir_sep(path[2]);
736 return is_dir_sep(path[0]);