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}
163int validate_headref(const char *path)
165{
166 struct stat st;
167 char *buf, buffer[256];
168 unsigned char sha1[20];
169 int fd;
170 ssize_t len;
171 if (lstat(path, &st) < 0)
173 return -1;
174 /* Make sure it is a "refs/.." symlink */
176 if (S_ISLNK(st.st_mode)) {
177 len = readlink(path, buffer, sizeof(buffer)-1);
178 if (len >= 5 && !memcmp("refs/", buffer, 5))
179 return 0;
180 return -1;
181 }
182 /*
184 * Anything else, just open it and try to see if it is a symbolic ref.
185 */
186 fd = open(path, O_RDONLY);
187 if (fd < 0)
188 return -1;
189 len = read_in_full(fd, buffer, sizeof(buffer)-1);
190 close(fd);
191 /*
193 * Is it a symbolic ref?
194 */
195 if (len < 4)
196 return -1;
197 if (!memcmp("ref:", buffer, 4)) {
198 buf = buffer + 4;
199 len -= 4;
200 while (len && isspace(*buf))
201 buf++, len--;
202 if (len >= 5 && !memcmp("refs/", buf, 5))
203 return 0;
204 }
205 /*
207 * Is this a detached HEAD?
208 */
209 if (!get_sha1_hex(buffer, sha1))
210 return 0;
211 return -1;
213}
214static struct passwd *getpw_str(const char *username, size_t len)
216{
217 struct passwd *pw;
218 char *username_z = xmalloc(len + 1);
219 memcpy(username_z, username, len);
220 username_z[len] = '\0';
221 pw = getpwnam(username_z);
222 free(username_z);
223 return pw;
224}
225/*
227 * Return a string with ~ and ~user expanded via getpw*. If buf != NULL,
228 * then it is a newly allocated string. Returns NULL on getpw failure or
229 * if path is NULL.
230 */
231char *expand_user_path(const char *path)
232{
233 struct strbuf user_path = STRBUF_INIT;
234 const char *first_slash = strchrnul(path, '/');
235 const char *to_copy = path;
236 if (path == NULL)
238 goto return_null;
239 if (path[0] == '~') {
240 const char *username = path + 1;
241 size_t username_len = first_slash - username;
242 if (username_len == 0) {
243 const char *home = getenv("HOME");
244 if (!home)
245 goto return_null;
246 strbuf_add(&user_path, home, strlen(home));
247 } else {
248 struct passwd *pw = getpw_str(username, username_len);
249 if (!pw)
250 goto return_null;
251 strbuf_add(&user_path, pw->pw_dir, strlen(pw->pw_dir));
252 }
253 to_copy = first_slash;
254 }
255 strbuf_add(&user_path, to_copy, strlen(to_copy));
256 return strbuf_detach(&user_path, NULL);
257return_null:
258 strbuf_release(&user_path);
259 return NULL;
260}
261/*
263 * First, one directory to try is determined by the following algorithm.
264 *
265 * (0) If "strict" is given, the path is used as given and no DWIM is
266 * done. Otherwise:
267 * (1) "~/path" to mean path under the running user's home directory;
268 * (2) "~user/path" to mean path under named user's home directory;
269 * (3) "relative/path" to mean cwd relative directory; or
270 * (4) "/absolute/path" to mean absolute directory.
271 *
272 * Unless "strict" is given, we try access() for existence of "%s.git/.git",
273 * "%s/.git", "%s.git", "%s" in this order. The first one that exists is
274 * what we try.
275 *
276 * Second, we try chdir() to that. Upon failure, we return NULL.
277 *
278 * Then, we try if the current directory is a valid git repository.
279 * Upon failure, we return NULL.
280 *
281 * If all goes well, we return the directory we used to chdir() (but
282 * before ~user is expanded), avoiding getcwd() resolving symbolic
283 * links. User relative paths are also returned as they are given,
284 * except DWIM suffixing.
285 */
286char *enter_repo(char *path, int strict)
287{
288 static char used_path[PATH_MAX];
289 static char validated_path[PATH_MAX];
290 if (!path)
292 return NULL;
293 if (!strict) {
295 static const char *suffix[] = {
296 ".git/.git", "/.git", ".git", "", NULL,
297 };
298 int len = strlen(path);
299 int i;
300 while ((1 < len) && (path[len-1] == '/')) {
301 path[len-1] = 0;
302 len--;
303 }
304 if (PATH_MAX <= len)
305 return NULL;
306 if (path[0] == '~') {
307 char *newpath = expand_user_path(path);
308 if (!newpath || (PATH_MAX - 10 < strlen(newpath))) {
309 free(newpath);
310 return NULL;
311 }
312 /*
313 * Copy back into the static buffer. A pity
314 * since newpath was not bounded, but other
315 * branches of the if are limited by PATH_MAX
316 * anyway.
317 */
318 strcpy(used_path, newpath); free(newpath);
319 strcpy(validated_path, path);
320 path = used_path;
321 }
322 else if (PATH_MAX - 10 < len)
323 return NULL;
324 else {
325 path = strcpy(used_path, path);
326 strcpy(validated_path, path);
327 }
328 len = strlen(path);
329 for (i = 0; suffix[i]; i++) {
330 strcpy(path + len, suffix[i]);
331 if (!access(path, F_OK)) {
332 strcat(validated_path, suffix[i]);
333 break;
334 }
335 }
336 if (!suffix[i] || chdir(path))
337 return NULL;
338 path = validated_path;
339 }
340 else if (chdir(path))
341 return NULL;
342 if (access("objects", X_OK) == 0 && access("refs", X_OK) == 0 &&
344 validate_headref("HEAD") == 0) {
345 set_git_dir(".");
346 check_repository_format();
347 return path;
348 }
349 return NULL;
351}
352int set_shared_perm(const char *path, int mode)
354{
355 struct stat st;
356 int tweak, shared, orig_mode;
357 if (!shared_repository) {
359 if (mode)
360 return chmod(path, mode & ~S_IFMT);
361 return 0;
362 }
363 if (!mode) {
364 if (lstat(path, &st) < 0)
365 return -1;
366 mode = st.st_mode;
367 orig_mode = mode;
368 } else
369 orig_mode = 0;
370 if (shared_repository < 0)
371 shared = -shared_repository;
372 else
373 shared = shared_repository;
374 tweak = shared;
375 if (!(mode & S_IWUSR))
377 tweak &= ~0222;
378 if (mode & S_IXUSR)
379 /* Copy read bits to execute bits */
380 tweak |= (tweak & 0444) >> 2;
381 if (shared_repository < 0)
382 mode = (mode & ~0777) | tweak;
383 else
384 mode |= tweak;
385 if (S_ISDIR(mode)) {
387 /* Copy read bits to execute bits */
388 mode |= (shared & 0444) >> 2;
389 mode |= FORCE_DIR_SET_GID;
390 }
391 if (((shared_repository < 0
393 ? (orig_mode & (FORCE_DIR_SET_GID | 0777))
394 : (orig_mode & mode)) != mode) &&
395 chmod(path, (mode & ~S_IFMT)) < 0)
396 return -2;
397 return 0;
398}
399const char *relative_path(const char *abs, const char *base)
401{
402 static char buf[PATH_MAX + 1];
403 int i = 0, j = 0;
404 if (!base || !base[0])
406 return abs;
407 while (base[i]) {
408 if (is_dir_sep(base[i])) {
409 if (!is_dir_sep(abs[j]))
410 return abs;
411 while (is_dir_sep(base[i]))
412 i++;
413 while (is_dir_sep(abs[j]))
414 j++;
415 continue;
416 } else if (abs[j] != base[i]) {
417 return abs;
418 }
419 i++;
420 j++;
421 }
422 if (
423 /* "/foo" is a prefix of "/foo" */
424 abs[j] &&
425 /* "/foo" is not a prefix of "/foobar" */
426 !is_dir_sep(base[i-1]) && !is_dir_sep(abs[j])
427 )
428 return abs;
429 while (is_dir_sep(abs[j]))
430 j++;
431 if (!abs[j])
432 strcpy(buf, ".");
433 else
434 strcpy(buf, abs + j);
435 return buf;
436}
437/*
439 * It is okay if dst == src, but they should not overlap otherwise.
440 *
441 * Performs the following normalizations on src, storing the result in dst:
442 * - Ensures that components are separated by '/' (Windows only)
443 * - Squashes sequences of '/'.
444 * - Removes "." components.
445 * - Removes ".." components, and the components the precede them.
446 * Returns failure (non-zero) if a ".." component appears as first path
447 * component anytime during the normalization. Otherwise, returns success (0).
448 *
449 * Note that this function is purely textual. It does not follow symlinks,
450 * verify the existence of the path, or make any system calls.
451 */
452int normalize_path_copy(char *dst, const char *src)
453{
454 char *dst0;
455 if (has_dos_drive_prefix(src)) {
457 *dst++ = *src++;
458 *dst++ = *src++;
459 }
460 dst0 = dst;
461 if (is_dir_sep(*src)) {
463 *dst++ = '/';
464 while (is_dir_sep(*src))
465 src++;
466 }
467 for (;;) {
469 char c = *src;
470 /*
472 * A path component that begins with . could be
473 * special:
474 * (1) "." and ends -- ignore and terminate.
475 * (2) "./" -- ignore them, eat slash and continue.
476 * (3) ".." and ends -- strip one and terminate.
477 * (4) "../" -- strip one, eat slash and continue.
478 */
479 if (c == '.') {
480 if (!src[1]) {
481 /* (1) */
482 src++;
483 } else if (is_dir_sep(src[1])) {
484 /* (2) */
485 src += 2;
486 while (is_dir_sep(*src))
487 src++;
488 continue;
489 } else if (src[1] == '.') {
490 if (!src[2]) {
491 /* (3) */
492 src += 2;
493 goto up_one;
494 } else if (is_dir_sep(src[2])) {
495 /* (4) */
496 src += 3;
497 while (is_dir_sep(*src))
498 src++;
499 goto up_one;
500 }
501 }
502 }
503 /* copy up to the next '/', and eat all '/' */
505 while ((c = *src++) != '\0' && !is_dir_sep(c))
506 *dst++ = c;
507 if (is_dir_sep(c)) {
508 *dst++ = '/';
509 while (is_dir_sep(c))
510 c = *src++;
511 src--;
512 } else if (!c)
513 break;
514 continue;
515 up_one:
517 /*
518 * dst0..dst is prefix portion, and dst[-1] is '/';
519 * go up one level.
520 */
521 dst--; /* go to trailing '/' */
522 if (dst <= dst0)
523 return -1;
524 /* Windows: dst[-1] cannot be backslash anymore */
525 while (dst0 < dst && dst[-1] != '/')
526 dst--;
527 }
528 *dst = '\0';
529 return 0;
530}
531/*
533 * path = Canonical absolute path
534 * prefix_list = Colon-separated list of absolute paths
535 *
536 * Determines, for each path in prefix_list, whether the "prefix" really
537 * is an ancestor directory of path. Returns the length of the longest
538 * ancestor directory, excluding any trailing slashes, or -1 if no prefix
539 * is an ancestor. (Note that this means 0 is returned if prefix_list is
540 * "/".) "/foo" is not considered an ancestor of "/foobar". Directories
541 * are not considered to be their own ancestors. path must be in a
542 * canonical form: empty components, or "." or ".." components are not
543 * allowed. prefix_list may be null, which is like "".
544 */
545int longest_ancestor_length(const char *path, const char *prefix_list)
546{
547 char buf[PATH_MAX+1];
548 const char *ceil, *colon;
549 int len, max_len = -1;
550 if (prefix_list == NULL || !strcmp(path, "/"))
552 return -1;
553 for (colon = ceil = prefix_list; *colon; ceil = colon+1) {
555 for (colon = ceil; *colon && *colon != PATH_SEP; colon++);
556 len = colon - ceil;
557 if (len == 0 || len > PATH_MAX || !is_absolute_path(ceil))
558 continue;
559 strlcpy(buf, ceil, len+1);
560 if (normalize_path_copy(buf, buf) < 0)
561 continue;
562 len = strlen(buf);
563 if (len > 0 && buf[len-1] == '/')
564 buf[--len] = '\0';
565 if (!strncmp(path, buf, len) &&
567 path[len] == '/' &&
568 len > max_len) {
569 max_len = len;
570 }
571 }
572 return max_len;
574}
575/* strip arbitrary amount of directory separators at end of path */
577static inline int chomp_trailing_dir_sep(const char *path, int len)
578{
579 while (len && is_dir_sep(path[len - 1]))
580 len--;
581 return len;
582}
583/*
585 * If path ends with suffix (complete path components), returns the
586 * part before suffix (sans trailing directory separators).
587 * Otherwise returns NULL.
588 */
589char *strip_path_suffix(const char *path, const char *suffix)
590{
591 int path_len = strlen(path), suffix_len = strlen(suffix);
592 while (suffix_len) {
594 if (!path_len)
595 return NULL;
596 if (is_dir_sep(path[path_len - 1])) {
598 if (!is_dir_sep(suffix[suffix_len - 1]))
599 return NULL;
600 path_len = chomp_trailing_dir_sep(path, path_len);
601 suffix_len = chomp_trailing_dir_sep(suffix, suffix_len);
602 }
603 else if (path[--path_len] != suffix[--suffix_len])
604 return NULL;
605 }
606 if (path_len && !is_dir_sep(path[path_len - 1]))
608 return NULL;
609 return xstrndup(path, chomp_trailing_dir_sep(path, path_len));
610}
611int daemon_avoid_alias(const char *p)
613{
614 int sl, ndot;
615 /*
617 * This resurrects the belts and suspenders paranoia check by HPA
618 * done in <435560F7.4080006@zytor.com> thread, now enter_repo()
619 * does not do getcwd() based path canonicalization.
620 *
621 * sl becomes true immediately after seeing '/' and continues to
622 * be true as long as dots continue after that without intervening
623 * non-dot character.
624 */
625 if (!p || (*p != '/' && *p != '~'))
626 return -1;
627 sl = 1; ndot = 0;
628 p++;
629 while (1) {
631 char ch = *p++;
632 if (sl) {
633 if (ch == '.')
634 ndot++;
635 else if (ch == '/') {
636 if (ndot < 3)
637 /* reject //, /./ and /../ */
638 return -1;
639 ndot = 0;
640 }
641 else if (ch == 0) {
642 if (0 < ndot && ndot < 3)
643 /* reject /.$ and /..$ */
644 return -1;
645 return 0;
646 }
647 else
648 sl = ndot = 0;
649 }
650 else if (ch == 0)
651 return 0;
652 else if (ch == '/') {
653 sl = 1;
654 ndot = 0;
655 }
656 }
657}
658int offset_1st_component(const char *path)
660{
661 if (has_dos_drive_prefix(path))
662 return 2 + is_dir_sep(path[2]);
663 return is_dir_sep(path[0]);
664}