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"
15#include "string-list.h"
16#ifndef get_st_mode_bits
18/*
19 * The replacement lstat(2) we use on Cygwin is incomplete and
20 * may return wrong permission bits. Most of the time we do not care,
21 * but the callsites of this wrapper do care.
22 */
23int get_st_mode_bits(const char *path, int *mode)
24{
25 struct stat st;
26 if (lstat(path, &st) < 0)
27 return -1;
28 *mode = st.st_mode;
29 return 0;
30}
31#endif
32static char bad_path[] = "/bad-path/";
34static char *get_pathname(void)
36{
37 static char pathname_array[4][PATH_MAX];
38 static int index;
39 return pathname_array[3 & ++index];
40}
41static char *cleanup_path(char *path)
43{
44 /* Clean it up */
45 if (!memcmp(path, "./", 2)) {
46 path += 2;
47 while (*path == '/')
48 path++;
49 }
50 return path;
51}
52char *mksnpath(char *buf, size_t n, const char *fmt, ...)
54{
55 va_list args;
56 unsigned len;
57 va_start(args, fmt);
59 len = vsnprintf(buf, n, fmt, args);
60 va_end(args);
61 if (len >= n) {
62 strlcpy(buf, bad_path, n);
63 return buf;
64 }
65 return cleanup_path(buf);
66}
67static char *vsnpath(char *buf, size_t n, const char *fmt, va_list args)
69{
70 const char *git_dir = get_git_dir();
71 size_t len;
72 len = strlen(git_dir);
74 if (n < len + 1)
75 goto bad;
76 memcpy(buf, git_dir, len);
77 if (len && !is_dir_sep(git_dir[len-1]))
78 buf[len++] = '/';
79 len += vsnprintf(buf + len, n - len, fmt, args);
80 if (len >= n)
81 goto bad;
82 return cleanup_path(buf);
83bad:
84 strlcpy(buf, bad_path, n);
85 return buf;
86}
87char *git_snpath(char *buf, size_t n, const char *fmt, ...)
89{
90 char *ret;
91 va_list args;
92 va_start(args, fmt);
93 ret = vsnpath(buf, n, fmt, args);
94 va_end(args);
95 return ret;
96}
97char *git_pathdup(const char *fmt, ...)
99{
100 char path[PATH_MAX], *ret;
101 va_list args;
102 va_start(args, fmt);
103 ret = vsnpath(path, sizeof(path), fmt, args);
104 va_end(args);
105 return xstrdup(ret);
106}
107char *mkpathdup(const char *fmt, ...)
109{
110 char *path;
111 struct strbuf sb = STRBUF_INIT;
112 va_list args;
113 va_start(args, fmt);
115 strbuf_vaddf(&sb, fmt, args);
116 va_end(args);
117 path = xstrdup(cleanup_path(sb.buf));
118 strbuf_release(&sb);
120 return path;
121}
122char *mkpath(const char *fmt, ...)
124{
125 va_list args;
126 unsigned len;
127 char *pathname = get_pathname();
128 va_start(args, fmt);
130 len = vsnprintf(pathname, PATH_MAX, fmt, args);
131 va_end(args);
132 if (len >= PATH_MAX)
133 return bad_path;
134 return cleanup_path(pathname);
135}
136char *git_path(const char *fmt, ...)
138{
139 char *pathname = get_pathname();
140 va_list args;
141 char *ret;
142 va_start(args, fmt);
144 ret = vsnpath(pathname, PATH_MAX, fmt, args);
145 va_end(args);
146 return ret;
147}
148void home_config_paths(char **global, char **xdg, char *file)
150{
151 char *xdg_home = getenv("XDG_CONFIG_HOME");
152 char *home = getenv("HOME");
153 char *to_free = NULL;
154 if (!home) {
156 if (global)
157 *global = NULL;
158 } else {
159 if (!xdg_home) {
160 to_free = mkpathdup("%s/.config", home);
161 xdg_home = to_free;
162 }
163 if (global)
164 *global = mkpathdup("%s/.gitconfig", home);
165 }
166 if (!xdg_home)
168 *xdg = NULL;
169 else
170 *xdg = mkpathdup("%s/git/%s", xdg_home, file);
171 free(to_free);
173}
174char *git_path_submodule(const char *path, const char *fmt, ...)
176{
177 char *pathname = get_pathname();
178 struct strbuf buf = STRBUF_INIT;
179 const char *git_dir;
180 va_list args;
181 unsigned len;
182 len = strlen(path);
184 if (len > PATH_MAX-100)
185 return bad_path;
186 strbuf_addstr(&buf, path);
188 if (len && path[len-1] != '/')
189 strbuf_addch(&buf, '/');
190 strbuf_addstr(&buf, ".git");
191 git_dir = read_gitfile(buf.buf);
193 if (git_dir) {
194 strbuf_reset(&buf);
195 strbuf_addstr(&buf, git_dir);
196 }
197 strbuf_addch(&buf, '/');
198 if (buf.len >= PATH_MAX)
200 return bad_path;
201 memcpy(pathname, buf.buf, buf.len + 1);
202 strbuf_release(&buf);
204 len = strlen(pathname);
205 va_start(args, fmt);
207 len += vsnprintf(pathname + len, PATH_MAX - len, fmt, args);
208 va_end(args);
209 if (len >= PATH_MAX)
210 return bad_path;
211 return cleanup_path(pathname);
212}
213int validate_headref(const char *path)
215{
216 struct stat st;
217 char *buf, buffer[256];
218 unsigned char sha1[20];
219 int fd;
220 ssize_t len;
221 if (lstat(path, &st) < 0)
223 return -1;
224 /* Make sure it is a "refs/.." symlink */
226 if (S_ISLNK(st.st_mode)) {
227 len = readlink(path, buffer, sizeof(buffer)-1);
228 if (len >= 5 && !memcmp("refs/", buffer, 5))
229 return 0;
230 return -1;
231 }
232 /*
234 * Anything else, just open it and try to see if it is a symbolic ref.
235 */
236 fd = open(path, O_RDONLY);
237 if (fd < 0)
238 return -1;
239 len = read_in_full(fd, buffer, sizeof(buffer)-1);
240 close(fd);
241 /*
243 * Is it a symbolic ref?
244 */
245 if (len < 4)
246 return -1;
247 if (!memcmp("ref:", buffer, 4)) {
248 buf = buffer + 4;
249 len -= 4;
250 while (len && isspace(*buf))
251 buf++, len--;
252 if (len >= 5 && !memcmp("refs/", buf, 5))
253 return 0;
254 }
255 /*
257 * Is this a detached HEAD?
258 */
259 if (!get_sha1_hex(buffer, sha1))
260 return 0;
261 return -1;
263}
264static struct passwd *getpw_str(const char *username, size_t len)
266{
267 struct passwd *pw;
268 char *username_z = xmalloc(len + 1);
269 memcpy(username_z, username, len);
270 username_z[len] = '\0';
271 pw = getpwnam(username_z);
272 free(username_z);
273 return pw;
274}
275/*
277 * Return a string with ~ and ~user expanded via getpw*. If buf != NULL,
278 * then it is a newly allocated string. Returns NULL on getpw failure or
279 * if path is NULL.
280 */
281char *expand_user_path(const char *path)
282{
283 struct strbuf user_path = STRBUF_INIT;
284 const char *first_slash = strchrnul(path, '/');
285 const char *to_copy = path;
286 if (path == NULL)
288 goto return_null;
289 if (path[0] == '~') {
290 const char *username = path + 1;
291 size_t username_len = first_slash - username;
292 if (username_len == 0) {
293 const char *home = getenv("HOME");
294 if (!home)
295 goto return_null;
296 strbuf_add(&user_path, home, strlen(home));
297 } else {
298 struct passwd *pw = getpw_str(username, username_len);
299 if (!pw)
300 goto return_null;
301 strbuf_add(&user_path, pw->pw_dir, strlen(pw->pw_dir));
302 }
303 to_copy = first_slash;
304 }
305 strbuf_add(&user_path, to_copy, strlen(to_copy));
306 return strbuf_detach(&user_path, NULL);
307return_null:
308 strbuf_release(&user_path);
309 return NULL;
310}
311/*
313 * First, one directory to try is determined by the following algorithm.
314 *
315 * (0) If "strict" is given, the path is used as given and no DWIM is
316 * done. Otherwise:
317 * (1) "~/path" to mean path under the running user's home directory;
318 * (2) "~user/path" to mean path under named user's home directory;
319 * (3) "relative/path" to mean cwd relative directory; or
320 * (4) "/absolute/path" to mean absolute directory.
321 *
322 * Unless "strict" is given, we try access() for existence of "%s.git/.git",
323 * "%s/.git", "%s.git", "%s" in this order. The first one that exists is
324 * what we try.
325 *
326 * Second, we try chdir() to that. Upon failure, we return NULL.
327 *
328 * Then, we try if the current directory is a valid git repository.
329 * Upon failure, we return NULL.
330 *
331 * If all goes well, we return the directory we used to chdir() (but
332 * before ~user is expanded), avoiding getcwd() resolving symbolic
333 * links. User relative paths are also returned as they are given,
334 * except DWIM suffixing.
335 */
336const char *enter_repo(const char *path, int strict)
337{
338 static char used_path[PATH_MAX];
339 static char validated_path[PATH_MAX];
340 if (!path)
342 return NULL;
343 if (!strict) {
345 static const char *suffix[] = {
346 "/.git", "", ".git/.git", ".git", NULL,
347 };
348 const char *gitfile;
349 int len = strlen(path);
350 int i;
351 while ((1 < len) && (path[len-1] == '/'))
352 len--;
353 if (PATH_MAX <= len)
355 return NULL;
356 strncpy(used_path, path, len); used_path[len] = 0 ;
357 strcpy(validated_path, used_path);
358 if (used_path[0] == '~') {
360 char *newpath = expand_user_path(used_path);
361 if (!newpath || (PATH_MAX - 10 < strlen(newpath))) {
362 free(newpath);
363 return NULL;
364 }
365 /*
366 * Copy back into the static buffer. A pity
367 * since newpath was not bounded, but other
368 * branches of the if are limited by PATH_MAX
369 * anyway.
370 */
371 strcpy(used_path, newpath); free(newpath);
372 }
373 else if (PATH_MAX - 10 < len)
374 return NULL;
375 len = strlen(used_path);
376 for (i = 0; suffix[i]; i++) {
377 struct stat st;
378 strcpy(used_path + len, suffix[i]);
379 if (!stat(used_path, &st) &&
380 (S_ISREG(st.st_mode) ||
381 (S_ISDIR(st.st_mode) && is_git_directory(used_path)))) {
382 strcat(validated_path, suffix[i]);
383 break;
384 }
385 }
386 if (!suffix[i])
387 return NULL;
388 gitfile = read_gitfile(used_path) ;
389 if (gitfile)
390 strcpy(used_path, gitfile);
391 if (chdir(used_path))
392 return NULL;
393 path = validated_path;
394 }
395 else if (chdir(path))
396 return NULL;
397 if (access("objects", X_OK) == 0 && access("refs", X_OK) == 0 &&
399 validate_headref("HEAD") == 0) {
400 set_git_dir(".");
401 check_repository_format();
402 return path;
403 }
404 return NULL;
406}
407int set_shared_perm(const char *path, int mode)
409{
410 int tweak, shared, orig_mode;
411 if (!shared_repository) {
413 if (mode)
414 return chmod(path, mode & ~S_IFMT);
415 return 0;
416 }
417 if (!mode) {
418 if (get_st_mode_bits(path, &mode) < 0)
419 return -1;
420 orig_mode = mode;
421 } else
422 orig_mode = 0;
423 if (shared_repository < 0)
424 shared = -shared_repository;
425 else
426 shared = shared_repository;
427 tweak = shared;
428 if (!(mode & S_IWUSR))
430 tweak &= ~0222;
431 if (mode & S_IXUSR)
432 /* Copy read bits to execute bits */
433 tweak |= (tweak & 0444) >> 2;
434 if (shared_repository < 0)
435 mode = (mode & ~0777) | tweak;
436 else
437 mode |= tweak;
438 if (S_ISDIR(mode)) {
440 /* Copy read bits to execute bits */
441 mode |= (shared & 0444) >> 2;
442 mode |= FORCE_DIR_SET_GID;
443 }
444 if (((shared_repository < 0
446 ? (orig_mode & (FORCE_DIR_SET_GID | 0777))
447 : (orig_mode & mode)) != mode) &&
448 chmod(path, (mode & ~S_IFMT)) < 0)
449 return -2;
450 return 0;
451}
452const char *relative_path(const char *abs, const char *base)
454{
455 static char buf[PATH_MAX + 1];
456 int i = 0, j = 0;
457 if (!base || !base[0])
459 return abs;
460 while (base[i]) {
461 if (is_dir_sep(base[i])) {
462 if (!is_dir_sep(abs[j]))
463 return abs;
464 while (is_dir_sep(base[i]))
465 i++;
466 while (is_dir_sep(abs[j]))
467 j++;
468 continue;
469 } else if (abs[j] != base[i]) {
470 return abs;
471 }
472 i++;
473 j++;
474 }
475 if (
476 /* "/foo" is a prefix of "/foo" */
477 abs[j] &&
478 /* "/foo" is not a prefix of "/foobar" */
479 !is_dir_sep(base[i-1]) && !is_dir_sep(abs[j])
480 )
481 return abs;
482 while (is_dir_sep(abs[j]))
483 j++;
484 if (!abs[j])
485 strcpy(buf, ".");
486 else
487 strcpy(buf, abs + j);
488 return buf;
489}
490/*
492 * It is okay if dst == src, but they should not overlap otherwise.
493 *
494 * Performs the following normalizations on src, storing the result in dst:
495 * - Ensures that components are separated by '/' (Windows only)
496 * - Squashes sequences of '/'.
497 * - Removes "." components.
498 * - Removes ".." components, and the components the precede them.
499 * Returns failure (non-zero) if a ".." component appears as first path
500 * component anytime during the normalization. Otherwise, returns success (0).
501 *
502 * Note that this function is purely textual. It does not follow symlinks,
503 * verify the existence of the path, or make any system calls.
504 */
505int normalize_path_copy(char *dst, const char *src)
506{
507 char *dst0;
508 if (has_dos_drive_prefix(src)) {
510 *dst++ = *src++;
511 *dst++ = *src++;
512 }
513 dst0 = dst;
514 if (is_dir_sep(*src)) {
516 *dst++ = '/';
517 while (is_dir_sep(*src))
518 src++;
519 }
520 for (;;) {
522 char c = *src;
523 /*
525 * A path component that begins with . could be
526 * special:
527 * (1) "." and ends -- ignore and terminate.
528 * (2) "./" -- ignore them, eat slash and continue.
529 * (3) ".." and ends -- strip one and terminate.
530 * (4) "../" -- strip one, eat slash and continue.
531 */
532 if (c == '.') {
533 if (!src[1]) {
534 /* (1) */
535 src++;
536 } else if (is_dir_sep(src[1])) {
537 /* (2) */
538 src += 2;
539 while (is_dir_sep(*src))
540 src++;
541 continue;
542 } else if (src[1] == '.') {
543 if (!src[2]) {
544 /* (3) */
545 src += 2;
546 goto up_one;
547 } else if (is_dir_sep(src[2])) {
548 /* (4) */
549 src += 3;
550 while (is_dir_sep(*src))
551 src++;
552 goto up_one;
553 }
554 }
555 }
556 /* copy up to the next '/', and eat all '/' */
558 while ((c = *src++) != '\0' && !is_dir_sep(c))
559 *dst++ = c;
560 if (is_dir_sep(c)) {
561 *dst++ = '/';
562 while (is_dir_sep(c))
563 c = *src++;
564 src--;
565 } else if (!c)
566 break;
567 continue;
568 up_one:
570 /*
571 * dst0..dst is prefix portion, and dst[-1] is '/';
572 * go up one level.
573 */
574 dst--; /* go to trailing '/' */
575 if (dst <= dst0)
576 return -1;
577 /* Windows: dst[-1] cannot be backslash anymore */
578 while (dst0 < dst && dst[-1] != '/')
579 dst--;
580 }
581 *dst = '\0';
582 return 0;
583}
584/*
586 * path = Canonical absolute path
587 * prefixes = string_list containing normalized, absolute paths without
588 * trailing slashes (except for the root directory, which is denoted by "/").
589 *
590 * Determines, for each path in prefixes, whether the "prefix"
591 * is an ancestor directory of path. Returns the length of the longest
592 * ancestor directory, excluding any trailing slashes, or -1 if no prefix
593 * is an ancestor. (Note that this means 0 is returned if prefixes is
594 * ["/"].) "/foo" is not considered an ancestor of "/foobar". Directories
595 * are not considered to be their own ancestors. path must be in a
596 * canonical form: empty components, or "." or ".." components are not
597 * allowed.
598 */
599int longest_ancestor_length(const char *path, struct string_list *prefixes)
600{
601 int i, max_len = -1;
602 if (!strcmp(path, "/"))
604 return -1;
605 for (i = 0; i < prefixes->nr; i++) {
607 const char *ceil = prefixes->items[i].string;
608 int len = strlen(ceil);
609 if (len == 1 && ceil[0] == '/')
611 len = 0; /* root matches anything, with length 0 */
612 else if (!strncmp(path, ceil, len) && path[len] == '/')
613 ; /* match of length len */
614 else
615 continue; /* no match */
616 if (len > max_len)
618 max_len = len;
619 }
620 return max_len;
622}
623/* strip arbitrary amount of directory separators at end of path */
625static inline int chomp_trailing_dir_sep(const char *path, int len)
626{
627 while (len && is_dir_sep(path[len - 1]))
628 len--;
629 return len;
630}
631/*
633 * If path ends with suffix (complete path components), returns the
634 * part before suffix (sans trailing directory separators).
635 * Otherwise returns NULL.
636 */
637char *strip_path_suffix(const char *path, const char *suffix)
638{
639 int path_len = strlen(path), suffix_len = strlen(suffix);
640 while (suffix_len) {
642 if (!path_len)
643 return NULL;
644 if (is_dir_sep(path[path_len - 1])) {
646 if (!is_dir_sep(suffix[suffix_len - 1]))
647 return NULL;
648 path_len = chomp_trailing_dir_sep(path, path_len);
649 suffix_len = chomp_trailing_dir_sep(suffix, suffix_len);
650 }
651 else if (path[--path_len] != suffix[--suffix_len])
652 return NULL;
653 }
654 if (path_len && !is_dir_sep(path[path_len - 1]))
656 return NULL;
657 return xstrndup(path, chomp_trailing_dir_sep(path, path_len));
658}
659int daemon_avoid_alias(const char *p)
661{
662 int sl, ndot;
663 /*
665 * This resurrects the belts and suspenders paranoia check by HPA
666 * done in <435560F7.4080006@zytor.com> thread, now enter_repo()
667 * does not do getcwd() based path canonicalization.
668 *
669 * sl becomes true immediately after seeing '/' and continues to
670 * be true as long as dots continue after that without intervening
671 * non-dot character.
672 */
673 if (!p || (*p != '/' && *p != '~'))
674 return -1;
675 sl = 1; ndot = 0;
676 p++;
677 while (1) {
679 char ch = *p++;
680 if (sl) {
681 if (ch == '.')
682 ndot++;
683 else if (ch == '/') {
684 if (ndot < 3)
685 /* reject //, /./ and /../ */
686 return -1;
687 ndot = 0;
688 }
689 else if (ch == 0) {
690 if (0 < ndot && ndot < 3)
691 /* reject /.$ and /..$ */
692 return -1;
693 return 0;
694 }
695 else
696 sl = ndot = 0;
697 }
698 else if (ch == 0)
699 return 0;
700 else if (ch == '/') {
701 sl = 1;
702 ndot = 0;
703 }
704 }
705}
706int offset_1st_component(const char *path)
708{
709 if (has_dos_drive_prefix(path))
710 return 2 + is_dir_sep(path[2]);
711 return is_dir_sep(path[0]);
712}