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 *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 char *ret;
74 va_list args;
75 va_start(args, fmt);
76 ret = vsnpath(buf, n, fmt, args);
77 va_end(args);
78 return ret;
79}
80char *git_pathdup(const char *fmt, ...)
82{
83 char path[PATH_MAX], *ret;
84 va_list args;
85 va_start(args, fmt);
86 ret = vsnpath(path, sizeof(path), fmt, args);
87 va_end(args);
88 return xstrdup(ret);
89}
90char *mkpathdup(const char *fmt, ...)
92{
93 char *path;
94 struct strbuf sb = STRBUF_INIT;
95 va_list args;
96 va_start(args, fmt);
98 strbuf_vaddf(&sb, fmt, args);
99 va_end(args);
100 path = xstrdup(cleanup_path(sb.buf));
101 strbuf_release(&sb);
103 return path;
104}
105char *mkpath(const char *fmt, ...)
107{
108 va_list args;
109 unsigned len;
110 char *pathname = get_pathname();
111 va_start(args, fmt);
113 len = vsnprintf(pathname, PATH_MAX, fmt, args);
114 va_end(args);
115 if (len >= PATH_MAX)
116 return bad_path;
117 return cleanup_path(pathname);
118}
119char *git_path(const char *fmt, ...)
121{
122 const char *git_dir = get_git_dir();
123 char *pathname = get_pathname();
124 va_list args;
125 unsigned len;
126 len = strlen(git_dir);
128 if (len > PATH_MAX-100)
129 return bad_path;
130 memcpy(pathname, git_dir, len);
131 if (len && git_dir[len-1] != '/')
132 pathname[len++] = '/';
133 va_start(args, fmt);
134 len += vsnprintf(pathname + len, PATH_MAX - len, fmt, args);
135 va_end(args);
136 if (len >= PATH_MAX)
137 return bad_path;
138 return cleanup_path(pathname);
139}
140void home_config_paths(char **global, char **xdg, char *file)
142{
143 char *xdg_home = getenv("XDG_CONFIG_HOME");
144 char *home = getenv("HOME");
145 char *to_free = NULL;
146 if (!home) {
148 if (global)
149 *global = NULL;
150 } else {
151 if (!xdg_home) {
152 to_free = mkpathdup("%s/.config", home);
153 xdg_home = to_free;
154 }
155 if (global)
156 *global = mkpathdup("%s/.gitconfig", home);
157 }
158 if (!xdg_home)
160 *xdg = NULL;
161 else
162 *xdg = mkpathdup("%s/git/%s", xdg_home, file);
163 free(to_free);
165}
166char *git_path_submodule(const char *path, const char *fmt, ...)
168{
169 char *pathname = get_pathname();
170 struct strbuf buf = STRBUF_INIT;
171 const char *git_dir;
172 va_list args;
173 unsigned len;
174 len = strlen(path);
176 if (len > PATH_MAX-100)
177 return bad_path;
178 strbuf_addstr(&buf, path);
180 if (len && path[len-1] != '/')
181 strbuf_addch(&buf, '/');
182 strbuf_addstr(&buf, ".git");
183 git_dir = read_gitfile(buf.buf);
185 if (git_dir) {
186 strbuf_reset(&buf);
187 strbuf_addstr(&buf, git_dir);
188 }
189 strbuf_addch(&buf, '/');
190 if (buf.len >= PATH_MAX)
192 return bad_path;
193 memcpy(pathname, buf.buf, buf.len + 1);
194 strbuf_release(&buf);
196 len = strlen(pathname);
197 va_start(args, fmt);
199 len += vsnprintf(pathname + len, PATH_MAX - len, fmt, args);
200 va_end(args);
201 if (len >= PATH_MAX)
202 return bad_path;
203 return cleanup_path(pathname);
204}
205int validate_headref(const char *path)
207{
208 struct stat st;
209 char *buf, buffer[256];
210 unsigned char sha1[20];
211 int fd;
212 ssize_t len;
213 if (lstat(path, &st) < 0)
215 return -1;
216 /* Make sure it is a "refs/.." symlink */
218 if (S_ISLNK(st.st_mode)) {
219 len = readlink(path, buffer, sizeof(buffer)-1);
220 if (len >= 5 && !memcmp("refs/", buffer, 5))
221 return 0;
222 return -1;
223 }
224 /*
226 * Anything else, just open it and try to see if it is a symbolic ref.
227 */
228 fd = open(path, O_RDONLY);
229 if (fd < 0)
230 return -1;
231 len = read_in_full(fd, buffer, sizeof(buffer)-1);
232 close(fd);
233 /*
235 * Is it a symbolic ref?
236 */
237 if (len < 4)
238 return -1;
239 if (!memcmp("ref:", buffer, 4)) {
240 buf = buffer + 4;
241 len -= 4;
242 while (len && isspace(*buf))
243 buf++, len--;
244 if (len >= 5 && !memcmp("refs/", buf, 5))
245 return 0;
246 }
247 /*
249 * Is this a detached HEAD?
250 */
251 if (!get_sha1_hex(buffer, sha1))
252 return 0;
253 return -1;
255}
256static struct passwd *getpw_str(const char *username, size_t len)
258{
259 struct passwd *pw;
260 char *username_z = xmalloc(len + 1);
261 memcpy(username_z, username, len);
262 username_z[len] = '\0';
263 pw = getpwnam(username_z);
264 free(username_z);
265 return pw;
266}
267/*
269 * Return a string with ~ and ~user expanded via getpw*. If buf != NULL,
270 * then it is a newly allocated string. Returns NULL on getpw failure or
271 * if path is NULL.
272 */
273char *expand_user_path(const char *path)
274{
275 struct strbuf user_path = STRBUF_INIT;
276 const char *first_slash = strchrnul(path, '/');
277 const char *to_copy = path;
278 if (path == NULL)
280 goto return_null;
281 if (path[0] == '~') {
282 const char *username = path + 1;
283 size_t username_len = first_slash - username;
284 if (username_len == 0) {
285 const char *home = getenv("HOME");
286 if (!home)
287 goto return_null;
288 strbuf_add(&user_path, home, strlen(home));
289 } else {
290 struct passwd *pw = getpw_str(username, username_len);
291 if (!pw)
292 goto return_null;
293 strbuf_add(&user_path, pw->pw_dir, strlen(pw->pw_dir));
294 }
295 to_copy = first_slash;
296 }
297 strbuf_add(&user_path, to_copy, strlen(to_copy));
298 return strbuf_detach(&user_path, NULL);
299return_null:
300 strbuf_release(&user_path);
301 return NULL;
302}
303/*
305 * First, one directory to try is determined by the following algorithm.
306 *
307 * (0) If "strict" is given, the path is used as given and no DWIM is
308 * done. Otherwise:
309 * (1) "~/path" to mean path under the running user's home directory;
310 * (2) "~user/path" to mean path under named user's home directory;
311 * (3) "relative/path" to mean cwd relative directory; or
312 * (4) "/absolute/path" to mean absolute directory.
313 *
314 * Unless "strict" is given, we try access() for existence of "%s.git/.git",
315 * "%s/.git", "%s.git", "%s" in this order. The first one that exists is
316 * what we try.
317 *
318 * Second, we try chdir() to that. Upon failure, we return NULL.
319 *
320 * Then, we try if the current directory is a valid git repository.
321 * Upon failure, we return NULL.
322 *
323 * If all goes well, we return the directory we used to chdir() (but
324 * before ~user is expanded), avoiding getcwd() resolving symbolic
325 * links. User relative paths are also returned as they are given,
326 * except DWIM suffixing.
327 */
328const char *enter_repo(const char *path, int strict)
329{
330 static char used_path[PATH_MAX];
331 static char validated_path[PATH_MAX];
332 if (!path)
334 return NULL;
335 if (!strict) {
337 static const char *suffix[] = {
338 "/.git", "", ".git/.git", ".git", NULL,
339 };
340 const char *gitfile;
341 int len = strlen(path);
342 int i;
343 while ((1 < len) && (path[len-1] == '/'))
344 len--;
345 if (PATH_MAX <= len)
347 return NULL;
348 strncpy(used_path, path, len); used_path[len] = 0 ;
349 strcpy(validated_path, used_path);
350 if (used_path[0] == '~') {
352 char *newpath = expand_user_path(used_path);
353 if (!newpath || (PATH_MAX - 10 < strlen(newpath))) {
354 free(newpath);
355 return NULL;
356 }
357 /*
358 * Copy back into the static buffer. A pity
359 * since newpath was not bounded, but other
360 * branches of the if are limited by PATH_MAX
361 * anyway.
362 */
363 strcpy(used_path, newpath); free(newpath);
364 }
365 else if (PATH_MAX - 10 < len)
366 return NULL;
367 len = strlen(used_path);
368 for (i = 0; suffix[i]; i++) {
369 struct stat st;
370 strcpy(used_path + len, suffix[i]);
371 if (!stat(used_path, &st) &&
372 (S_ISREG(st.st_mode) ||
373 (S_ISDIR(st.st_mode) && is_git_directory(used_path)))) {
374 strcat(validated_path, suffix[i]);
375 break;
376 }
377 }
378 if (!suffix[i])
379 return NULL;
380 gitfile = read_gitfile(used_path) ;
381 if (gitfile)
382 strcpy(used_path, gitfile);
383 if (chdir(used_path))
384 return NULL;
385 path = validated_path;
386 }
387 else if (chdir(path))
388 return NULL;
389 if (access("objects", X_OK) == 0 && access("refs", X_OK) == 0 &&
391 validate_headref("HEAD") == 0) {
392 set_git_dir(".");
393 check_repository_format();
394 return path;
395 }
396 return NULL;
398}
399int set_shared_perm(const char *path, int mode)
401{
402 struct stat st;
403 int tweak, shared, orig_mode;
404 if (!shared_repository) {
406 if (mode)
407 return chmod(path, mode & ~S_IFMT);
408 return 0;
409 }
410 if (!mode) {
411 if (lstat(path, &st) < 0)
412 return -1;
413 mode = st.st_mode;
414 orig_mode = mode;
415 } else
416 orig_mode = 0;
417 if (shared_repository < 0)
418 shared = -shared_repository;
419 else
420 shared = shared_repository;
421 tweak = shared;
422 if (!(mode & S_IWUSR))
424 tweak &= ~0222;
425 if (mode & S_IXUSR)
426 /* Copy read bits to execute bits */
427 tweak |= (tweak & 0444) >> 2;
428 if (shared_repository < 0)
429 mode = (mode & ~0777) | tweak;
430 else
431 mode |= tweak;
432 if (S_ISDIR(mode)) {
434 /* Copy read bits to execute bits */
435 mode |= (shared & 0444) >> 2;
436 mode |= FORCE_DIR_SET_GID;
437 }
438 if (((shared_repository < 0
440 ? (orig_mode & (FORCE_DIR_SET_GID | 0777))
441 : (orig_mode & mode)) != mode) &&
442 chmod(path, (mode & ~S_IFMT)) < 0)
443 return -2;
444 return 0;
445}
446const char *relative_path(const char *abs, const char *base)
448{
449 static char buf[PATH_MAX + 1];
450 int i = 0, j = 0;
451 if (!base || !base[0])
453 return abs;
454 while (base[i]) {
455 if (is_dir_sep(base[i])) {
456 if (!is_dir_sep(abs[j]))
457 return abs;
458 while (is_dir_sep(base[i]))
459 i++;
460 while (is_dir_sep(abs[j]))
461 j++;
462 continue;
463 } else if (abs[j] != base[i]) {
464 return abs;
465 }
466 i++;
467 j++;
468 }
469 if (
470 /* "/foo" is a prefix of "/foo" */
471 abs[j] &&
472 /* "/foo" is not a prefix of "/foobar" */
473 !is_dir_sep(base[i-1]) && !is_dir_sep(abs[j])
474 )
475 return abs;
476 while (is_dir_sep(abs[j]))
477 j++;
478 if (!abs[j])
479 strcpy(buf, ".");
480 else
481 strcpy(buf, abs + j);
482 return buf;
483}
484/*
486 * It is okay if dst == src, but they should not overlap otherwise.
487 *
488 * Performs the following normalizations on src, storing the result in dst:
489 * - Ensures that components are separated by '/' (Windows only)
490 * - Squashes sequences of '/'.
491 * - Removes "." components.
492 * - Removes ".." components, and the components the precede them.
493 * Returns failure (non-zero) if a ".." component appears as first path
494 * component anytime during the normalization. Otherwise, returns success (0).
495 *
496 * Note that this function is purely textual. It does not follow symlinks,
497 * verify the existence of the path, or make any system calls.
498 */
499int normalize_path_copy(char *dst, const char *src)
500{
501 char *dst0;
502 if (has_dos_drive_prefix(src)) {
504 *dst++ = *src++;
505 *dst++ = *src++;
506 }
507 dst0 = dst;
508 if (is_dir_sep(*src)) {
510 *dst++ = '/';
511 while (is_dir_sep(*src))
512 src++;
513 }
514 for (;;) {
516 char c = *src;
517 /*
519 * A path component that begins with . could be
520 * special:
521 * (1) "." and ends -- ignore and terminate.
522 * (2) "./" -- ignore them, eat slash and continue.
523 * (3) ".." and ends -- strip one and terminate.
524 * (4) "../" -- strip one, eat slash and continue.
525 */
526 if (c == '.') {
527 if (!src[1]) {
528 /* (1) */
529 src++;
530 } else if (is_dir_sep(src[1])) {
531 /* (2) */
532 src += 2;
533 while (is_dir_sep(*src))
534 src++;
535 continue;
536 } else if (src[1] == '.') {
537 if (!src[2]) {
538 /* (3) */
539 src += 2;
540 goto up_one;
541 } else if (is_dir_sep(src[2])) {
542 /* (4) */
543 src += 3;
544 while (is_dir_sep(*src))
545 src++;
546 goto up_one;
547 }
548 }
549 }
550 /* copy up to the next '/', and eat all '/' */
552 while ((c = *src++) != '\0' && !is_dir_sep(c))
553 *dst++ = c;
554 if (is_dir_sep(c)) {
555 *dst++ = '/';
556 while (is_dir_sep(c))
557 c = *src++;
558 src--;
559 } else if (!c)
560 break;
561 continue;
562 up_one:
564 /*
565 * dst0..dst is prefix portion, and dst[-1] is '/';
566 * go up one level.
567 */
568 dst--; /* go to trailing '/' */
569 if (dst <= dst0)
570 return -1;
571 /* Windows: dst[-1] cannot be backslash anymore */
572 while (dst0 < dst && dst[-1] != '/')
573 dst--;
574 }
575 *dst = '\0';
576 return 0;
577}
578/*
580 * path = Canonical absolute path
581 * prefix_list = Colon-separated list of absolute paths
582 *
583 * Determines, for each path in prefix_list, whether the "prefix" really
584 * is an ancestor directory of path. Returns the length of the longest
585 * ancestor directory, excluding any trailing slashes, or -1 if no prefix
586 * is an ancestor. (Note that this means 0 is returned if prefix_list is
587 * "/".) "/foo" is not considered an ancestor of "/foobar". Directories
588 * are not considered to be their own ancestors. path must be in a
589 * canonical form: empty components, or "." or ".." components are not
590 * allowed. prefix_list may be null, which is like "".
591 */
592int longest_ancestor_length(const char *path, const char *prefix_list)
593{
594 char buf[PATH_MAX+1];
595 const char *ceil, *colon;
596 int len, max_len = -1;
597 if (prefix_list == NULL || !strcmp(path, "/"))
599 return -1;
600 for (colon = ceil = prefix_list; *colon; ceil = colon+1) {
602 for (colon = ceil; *colon && *colon != PATH_SEP; colon++);
603 len = colon - ceil;
604 if (len == 0 || len > PATH_MAX || !is_absolute_path(ceil))
605 continue;
606 strlcpy(buf, ceil, len+1);
607 if (normalize_path_copy(buf, buf) < 0)
608 continue;
609 len = strlen(buf);
610 if (len > 0 && buf[len-1] == '/')
611 buf[--len] = '\0';
612 if (!strncmp(path, buf, len) &&
614 path[len] == '/' &&
615 len > max_len) {
616 max_len = len;
617 }
618 }
619 return max_len;
621}
622/* strip arbitrary amount of directory separators at end of path */
624static inline int chomp_trailing_dir_sep(const char *path, int len)
625{
626 while (len && is_dir_sep(path[len - 1]))
627 len--;
628 return len;
629}
630/*
632 * If path ends with suffix (complete path components), returns the
633 * part before suffix (sans trailing directory separators).
634 * Otherwise returns NULL.
635 */
636char *strip_path_suffix(const char *path, const char *suffix)
637{
638 int path_len = strlen(path), suffix_len = strlen(suffix);
639 while (suffix_len) {
641 if (!path_len)
642 return NULL;
643 if (is_dir_sep(path[path_len - 1])) {
645 if (!is_dir_sep(suffix[suffix_len - 1]))
646 return NULL;
647 path_len = chomp_trailing_dir_sep(path, path_len);
648 suffix_len = chomp_trailing_dir_sep(suffix, suffix_len);
649 }
650 else if (path[--path_len] != suffix[--suffix_len])
651 return NULL;
652 }
653 if (path_len && !is_dir_sep(path[path_len - 1]))
655 return NULL;
656 return xstrndup(path, chomp_trailing_dir_sep(path, path_len));
657}
658int daemon_avoid_alias(const char *p)
660{
661 int sl, ndot;
662 /*
664 * This resurrects the belts and suspenders paranoia check by HPA
665 * done in <435560F7.4080006@zytor.com> thread, now enter_repo()
666 * does not do getcwd() based path canonicalization.
667 *
668 * sl becomes true immediately after seeing '/' and continues to
669 * be true as long as dots continue after that without intervening
670 * non-dot character.
671 */
672 if (!p || (*p != '/' && *p != '~'))
673 return -1;
674 sl = 1; ndot = 0;
675 p++;
676 while (1) {
678 char ch = *p++;
679 if (sl) {
680 if (ch == '.')
681 ndot++;
682 else if (ch == '/') {
683 if (ndot < 3)
684 /* reject //, /./ and /../ */
685 return -1;
686 ndot = 0;
687 }
688 else if (ch == 0) {
689 if (0 < ndot && ndot < 3)
690 /* reject /.$ and /..$ */
691 return -1;
692 return 0;
693 }
694 else
695 sl = ndot = 0;
696 }
697 else if (ch == 0)
698 return 0;
699 else if (ch == '/') {
700 sl = 1;
701 ndot = 0;
702 }
703 }
704}
705int offset_1st_component(const char *path)
707{
708 if (has_dos_drive_prefix(path))
709 return 2 + is_dir_sep(path[2]);
710 return is_dir_sep(path[0]);
711}