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"
14static char bad_path[] = "/bad-path/";
16static char *get_pathname(void)
18{
19 static char pathname_array[4][PATH_MAX];
20 static int index;
21 return pathname_array[3 & ++index];
22}
23static char *cleanup_path(char *path)
25{
26 /* Clean it up */
27 if (!memcmp(path, "./", 2)) {
28 path += 2;
29 while (*path == '/')
30 path++;
31 }
32 return path;
33}
34char *mksnpath(char *buf, size_t n, const char *fmt, ...)
36{
37 va_list args;
38 unsigned len;
39 va_start(args, fmt);
41 len = vsnprintf(buf, n, fmt, args);
42 va_end(args);
43 if (len >= n) {
44 strlcpy(buf, bad_path, n);
45 return buf;
46 }
47 return cleanup_path(buf);
48}
49static char *git_vsnpath(char *buf, size_t n, const char *fmt, va_list args)
51{
52 const char *git_dir = get_git_dir();
53 size_t len;
54 len = strlen(git_dir);
56 if (n < len + 1)
57 goto bad;
58 memcpy(buf, git_dir, len);
59 if (len && !is_dir_sep(git_dir[len-1]))
60 buf[len++] = '/';
61 len += vsnprintf(buf + len, n - len, fmt, args);
62 if (len >= n)
63 goto bad;
64 return cleanup_path(buf);
65bad:
66 strlcpy(buf, bad_path, n);
67 return buf;
68}
69char *git_snpath(char *buf, size_t n, const char *fmt, ...)
71{
72 va_list args;
73 va_start(args, fmt);
74 (void)git_vsnpath(buf, n, fmt, args);
75 va_end(args);
76 return buf;
77}
78char *git_pathdup(const char *fmt, ...)
80{
81 char path[PATH_MAX];
82 va_list args;
83 va_start(args, fmt);
84 (void)git_vsnpath(path, sizeof(path), fmt, args);
85 va_end(args);
86 return xstrdup(path);
87}
88char *mkpath(const char *fmt, ...)
90{
91 va_list args;
92 unsigned len;
93 char *pathname = get_pathname();
94 va_start(args, fmt);
96 len = vsnprintf(pathname, PATH_MAX, fmt, args);
97 va_end(args);
98 if (len >= PATH_MAX)
99 return bad_path;
100 return cleanup_path(pathname);
101}
102char *git_path(const char *fmt, ...)
104{
105 const char *git_dir = get_git_dir();
106 char *pathname = get_pathname();
107 va_list args;
108 unsigned len;
109 len = strlen(git_dir);
111 if (len > PATH_MAX-100)
112 return bad_path;
113 memcpy(pathname, git_dir, len);
114 if (len && git_dir[len-1] != '/')
115 pathname[len++] = '/';
116 va_start(args, fmt);
117 len += vsnprintf(pathname + len, PATH_MAX - len, fmt, args);
118 va_end(args);
119 if (len >= PATH_MAX)
120 return bad_path;
121 return cleanup_path(pathname);
122}
123/* git_mkstemp() - create tmp file honoring TMPDIR variable */
126int git_mkstemp(char *path, size_t len, const char *template)
127{
128 const char *tmp;
129 size_t n;
130 tmp = getenv("TMPDIR");
132 if (!tmp)
133 tmp = "/tmp";
134 n = snprintf(path, len, "%s/%s", tmp, template);
135 if (len <= n) {
136 errno = ENAMETOOLONG;
137 return -1;
138 }
139 return mkstemp(path);
140}
141int validate_headref(const char *path)
144{
145 struct stat st;
146 char *buf, buffer[256];
147 unsigned char sha1[20];
148 int fd;
149 ssize_t len;
150 if (lstat(path, &st) < 0)
152 return -1;
153 /* Make sure it is a "refs/.." symlink */
155 if (S_ISLNK(st.st_mode)) {
156 len = readlink(path, buffer, sizeof(buffer)-1);
157 if (len >= 5 && !memcmp("refs/", buffer, 5))
158 return 0;
159 return -1;
160 }
161 /*
163 * Anything else, just open it and try to see if it is a symbolic ref.
164 */
165 fd = open(path, O_RDONLY);
166 if (fd < 0)
167 return -1;
168 len = read_in_full(fd, buffer, sizeof(buffer)-1);
169 close(fd);
170 /*
172 * Is it a symbolic ref?
173 */
174 if (len < 4)
175 return -1;
176 if (!memcmp("ref:", buffer, 4)) {
177 buf = buffer + 4;
178 len -= 4;
179 while (len && isspace(*buf))
180 buf++, len--;
181 if (len >= 5 && !memcmp("refs/", buf, 5))
182 return 0;
183 }
184 /*
186 * Is this a detached HEAD?
187 */
188 if (!get_sha1_hex(buffer, sha1))
189 return 0;
190 return -1;
192}
193static char *user_path(char *buf, char *path, int sz)
195{
196 struct passwd *pw;
197 char *slash;
198 int len, baselen;
199 if (!path || path[0] != '~')
201 return NULL;
202 path++;
203 slash = strchr(path, '/');
204 if (path[0] == '/' || !path[0]) {
205 pw = getpwuid(getuid());
206 }
207 else {
208 if (slash) {
209 *slash = 0;
210 pw = getpwnam(path);
211 *slash = '/';
212 }
213 else
214 pw = getpwnam(path);
215 }
216 if (!pw || !pw->pw_dir || sz <= strlen(pw->pw_dir))
217 return NULL;
218 baselen = strlen(pw->pw_dir);
219 memcpy(buf, pw->pw_dir, baselen);
220 while ((1 < baselen) && (buf[baselen-1] == '/')) {
221 buf[baselen-1] = 0;
222 baselen--;
223 }
224 if (slash && slash[1]) {
225 len = strlen(slash);
226 if (sz <= baselen + len)
227 return NULL;
228 memcpy(buf + baselen, slash, len + 1);
229 }
230 return buf;
231}
232/*
234 * First, one directory to try is determined by the following algorithm.
235 *
236 * (0) If "strict" is given, the path is used as given and no DWIM is
237 * done. Otherwise:
238 * (1) "~/path" to mean path under the running user's home directory;
239 * (2) "~user/path" to mean path under named user's home directory;
240 * (3) "relative/path" to mean cwd relative directory; or
241 * (4) "/absolute/path" to mean absolute directory.
242 *
243 * Unless "strict" is given, we try access() for existence of "%s.git/.git",
244 * "%s/.git", "%s.git", "%s" in this order. The first one that exists is
245 * what we try.
246 *
247 * Second, we try chdir() to that. Upon failure, we return NULL.
248 *
249 * Then, we try if the current directory is a valid git repository.
250 * Upon failure, we return NULL.
251 *
252 * If all goes well, we return the directory we used to chdir() (but
253 * before ~user is expanded), avoiding getcwd() resolving symbolic
254 * links. User relative paths are also returned as they are given,
255 * except DWIM suffixing.
256 */
257char *enter_repo(char *path, int strict)
258{
259 static char used_path[PATH_MAX];
260 static char validated_path[PATH_MAX];
261 if (!path)
263 return NULL;
264 if (!strict) {
266 static const char *suffix[] = {
267 ".git/.git", "/.git", ".git", "", NULL,
268 };
269 int len = strlen(path);
270 int i;
271 while ((1 < len) && (path[len-1] == '/')) {
272 path[len-1] = 0;
273 len--;
274 }
275 if (PATH_MAX <= len)
276 return NULL;
277 if (path[0] == '~') {
278 if (!user_path(used_path, path, PATH_MAX))
279 return NULL;
280 strcpy(validated_path, path);
281 path = used_path;
282 }
283 else if (PATH_MAX - 10 < len)
284 return NULL;
285 else {
286 path = strcpy(used_path, path);
287 strcpy(validated_path, path);
288 }
289 len = strlen(path);
290 for (i = 0; suffix[i]; i++) {
291 strcpy(path + len, suffix[i]);
292 if (!access(path, F_OK)) {
293 strcat(validated_path, suffix[i]);
294 break;
295 }
296 }
297 if (!suffix[i] || chdir(path))
298 return NULL;
299 path = validated_path;
300 }
301 else if (chdir(path))
302 return NULL;
303 if (access("objects", X_OK) == 0 && access("refs", X_OK) == 0 &&
305 validate_headref("HEAD") == 0) {
306 setenv(GIT_DIR_ENVIRONMENT, ".", 1);
307 check_repository_format();
308 return path;
309 }
310 return NULL;
312}
313int set_shared_perm(const char *path, int mode)
315{
316 struct stat st;
317 int tweak, shared, orig_mode;
318 if (!shared_repository) {
320 if (mode)
321 return chmod(path, mode & ~S_IFMT);
322 return 0;
323 }
324 if (!mode) {
325 if (lstat(path, &st) < 0)
326 return -1;
327 mode = st.st_mode;
328 orig_mode = mode;
329 } else
330 orig_mode = 0;
331 if (shared_repository < 0)
332 shared = -shared_repository;
333 else
334 shared = shared_repository;
335 tweak = shared;
336 if (!(mode & S_IWUSR))
338 tweak &= ~0222;
339 if (mode & S_IXUSR)
340 /* Copy read bits to execute bits */
341 tweak |= (tweak & 0444) >> 2;
342 if (shared_repository < 0)
343 mode = (mode & ~0777) | tweak;
344 else
345 mode |= tweak;
346 if (S_ISDIR(mode)) {
348 /* Copy read bits to execute bits */
349 mode |= (shared & 0444) >> 2;
350 mode |= FORCE_DIR_SET_GID;
351 }
352 if (((shared_repository < 0
354 ? (orig_mode & (FORCE_DIR_SET_GID | 0777))
355 : (orig_mode & mode)) != mode) &&
356 chmod(path, (mode & ~S_IFMT)) < 0)
357 return -2;
358 return 0;
359}
360const char *make_relative_path(const char *abs, const char *base)
362{
363 static char buf[PATH_MAX + 1];
364 int baselen;
365 if (!base)
366 return abs;
367 baselen = strlen(base);
368 if (prefixcmp(abs, base))
369 return abs;
370 if (abs[baselen] == '/')
371 baselen++;
372 else if (base[baselen - 1] != '/')
373 return abs;
374 strcpy(buf, abs + baselen);
375 return buf;
376}
377/*
379 * It is okay if dst == src, but they should not overlap otherwise.
380 *
381 * Performs the following normalizations on src, storing the result in dst:
382 * - Ensures that components are separated by '/' (Windows only)
383 * - Squashes sequences of '/'.
384 * - Removes "." components.
385 * - Removes ".." components, and the components the precede them.
386 * Returns failure (non-zero) if a ".." component appears as first path
387 * component anytime during the normalization. Otherwise, returns success (0).
388 *
389 * Note that this function is purely textual. It does not follow symlinks,
390 * verify the existence of the path, or make any system calls.
391 */
392int normalize_path_copy(char *dst, const char *src)
393{
394 char *dst0;
395 if (has_dos_drive_prefix(src)) {
397 *dst++ = *src++;
398 *dst++ = *src++;
399 }
400 dst0 = dst;
401 if (is_dir_sep(*src)) {
403 *dst++ = '/';
404 while (is_dir_sep(*src))
405 src++;
406 }
407 for (;;) {
409 char c = *src;
410 /*
412 * A path component that begins with . could be
413 * special:
414 * (1) "." and ends -- ignore and terminate.
415 * (2) "./" -- ignore them, eat slash and continue.
416 * (3) ".." and ends -- strip one and terminate.
417 * (4) "../" -- strip one, eat slash and continue.
418 */
419 if (c == '.') {
420 if (!src[1]) {
421 /* (1) */
422 src++;
423 } else if (is_dir_sep(src[1])) {
424 /* (2) */
425 src += 2;
426 while (is_dir_sep(*src))
427 src++;
428 continue;
429 } else if (src[1] == '.') {
430 if (!src[2]) {
431 /* (3) */
432 src += 2;
433 goto up_one;
434 } else if (is_dir_sep(src[2])) {
435 /* (4) */
436 src += 3;
437 while (is_dir_sep(*src))
438 src++;
439 goto up_one;
440 }
441 }
442 }
443 /* copy up to the next '/', and eat all '/' */
445 while ((c = *src++) != '\0' && !is_dir_sep(c))
446 *dst++ = c;
447 if (is_dir_sep(c)) {
448 *dst++ = '/';
449 while (is_dir_sep(c))
450 c = *src++;
451 src--;
452 } else if (!c)
453 break;
454 continue;
455 up_one:
457 /*
458 * dst0..dst is prefix portion, and dst[-1] is '/';
459 * go up one level.
460 */
461 dst--; /* go to trailing '/' */
462 if (dst <= dst0)
463 return -1;
464 /* Windows: dst[-1] cannot be backslash anymore */
465 while (dst0 < dst && dst[-1] != '/')
466 dst--;
467 }
468 *dst = '\0';
469 return 0;
470}
471/*
473 * path = Canonical absolute path
474 * prefix_list = Colon-separated list of absolute paths
475 *
476 * Determines, for each path in prefix_list, whether the "prefix" really
477 * is an ancestor directory of path. Returns the length of the longest
478 * ancestor directory, excluding any trailing slashes, or -1 if no prefix
479 * is an ancestor. (Note that this means 0 is returned if prefix_list is
480 * "/".) "/foo" is not considered an ancestor of "/foobar". Directories
481 * are not considered to be their own ancestors. path must be in a
482 * canonical form: empty components, or "." or ".." components are not
483 * allowed. prefix_list may be null, which is like "".
484 */
485int longest_ancestor_length(const char *path, const char *prefix_list)
486{
487 char buf[PATH_MAX+1];
488 const char *ceil, *colon;
489 int len, max_len = -1;
490 if (prefix_list == NULL || !strcmp(path, "/"))
492 return -1;
493 for (colon = ceil = prefix_list; *colon; ceil = colon+1) {
495 for (colon = ceil; *colon && *colon != PATH_SEP; colon++);
496 len = colon - ceil;
497 if (len == 0 || len > PATH_MAX || !is_absolute_path(ceil))
498 continue;
499 strlcpy(buf, ceil, len+1);
500 if (normalize_path_copy(buf, buf) < 0)
501 continue;
502 len = strlen(buf);
503 if (len > 0 && buf[len-1] == '/')
504 buf[--len] = '\0';
505 if (!strncmp(path, buf, len) &&
507 path[len] == '/' &&
508 len > max_len) {
509 max_len = len;
510 }
511 }
512 return max_len;
514}
515/* strip arbitrary amount of directory separators at end of path */
517static inline int chomp_trailing_dir_sep(const char *path, int len)
518{
519 while (len && is_dir_sep(path[len - 1]))
520 len--;
521 return len;
522}
523/*
525 * If path ends with suffix (complete path components), returns the
526 * part before suffix (sans trailing directory separators).
527 * Otherwise returns NULL.
528 */
529char *strip_path_suffix(const char *path, const char *suffix)
530{
531 int path_len = strlen(path), suffix_len = strlen(suffix);
532 while (suffix_len) {
534 if (!path_len)
535 return NULL;
536 if (is_dir_sep(path[path_len - 1])) {
538 if (!is_dir_sep(suffix[suffix_len - 1]))
539 return NULL;
540 path_len = chomp_trailing_dir_sep(path, path_len);
541 suffix_len = chomp_trailing_dir_sep(suffix, suffix_len);
542 }
543 else if (path[--path_len] != suffix[--suffix_len])
544 return NULL;
545 }
546 if (path_len && !is_dir_sep(path[path_len - 1]))
548 return NULL;
549 return xstrndup(path, chomp_trailing_dir_sep(path, path_len));
550}