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"
15 static char bad_path[] = "/bad-path/";
17 static char *get_pathname(void)
18 {
19 static char pathname_array[4][PATH_MAX];
20 static int index;
21 return pathname_array[3 & ++index];
22 }
24 static 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 }
35 char *mksnpath(char *buf, size_t n, const char *fmt, ...)
36 {
37 va_list args;
38 unsigned len;
40 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 }
50 static 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;
55 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);
65 bad:
66 strlcpy(buf, bad_path, n);
67 return buf;
68 }
70 char *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 }
79 char *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 }
89 char *mkpath(const char *fmt, ...)
90 {
91 va_list args;
92 unsigned len;
93 char *pathname = get_pathname();
95 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 }
103 char *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;
110 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 }
125 /* git_mkstemp() - create tmp file honoring TMPDIR variable */
126 int git_mkstemp(char *path, size_t len, const char *template)
127 {
128 const char *tmp;
129 size_t n;
131 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 }
143 int 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;
151 if (lstat(path, &st) < 0)
152 return -1;
154 /* 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 }
162 /*
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);
171 /*
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 }
185 /*
186 * Is this a detached HEAD?
187 */
188 if (!get_sha1_hex(buffer, sha1))
189 return 0;
191 return -1;
192 }
194 static char *user_path(char *buf, char *path, int sz)
195 {
196 struct passwd *pw;
197 char *slash;
198 int len, baselen;
200 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 }
233 /*
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 */
257 char *enter_repo(char *path, int strict)
258 {
259 static char used_path[PATH_MAX];
260 static char validated_path[PATH_MAX];
262 if (!path)
263 return NULL;
265 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;
304 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 }
311 return NULL;
312 }
314 int adjust_shared_perm(const char *path)
315 {
316 struct stat st;
317 int mode;
319 if (!shared_repository)
320 return 0;
321 if (lstat(path, &st) < 0)
322 return -1;
323 mode = st.st_mode;
325 if (shared_repository) {
326 int tweak = shared_repository;
327 if (!(mode & S_IWUSR))
328 tweak &= ~0222;
329 mode |= tweak;
330 } else {
331 /* Preserve old PERM_UMASK behaviour */
332 if (mode & S_IWUSR)
333 mode |= S_IWGRP;
334 }
336 if (S_ISDIR(mode)) {
337 mode |= FORCE_DIR_SET_GID;
339 /* Copy read bits to execute bits */
340 mode |= (shared_repository & 0444) >> 2;
341 }
343 if ((mode & st.st_mode) != mode && chmod(path, mode) < 0)
344 return -2;
345 return 0;
346 }
348 const char *make_relative_path(const char *abs, const char *base)
349 {
350 static char buf[PATH_MAX + 1];
351 int baselen;
352 if (!base)
353 return abs;
354 baselen = strlen(base);
355 if (prefixcmp(abs, base))
356 return abs;
357 if (abs[baselen] == '/')
358 baselen++;
359 else if (base[baselen - 1] != '/')
360 return abs;
361 strcpy(buf, abs + baselen);
362 return buf;
363 }
365 /*
366 * It is okay if dst == src, but they should not overlap otherwise.
367 *
368 * Performs the following normalizations on src, storing the result in dst:
369 * - Ensures that components are separated by '/' (Windows only)
370 * - Squashes sequences of '/'.
371 * - Removes "." components.
372 * - Removes ".." components, and the components the precede them.
373 * Returns failure (non-zero) if a ".." component appears as first path
374 * component anytime during the normalization. Otherwise, returns success (0).
375 *
376 * Note that this function is purely textual. It does not follow symlinks,
377 * verify the existence of the path, or make any system calls.
378 */
379 int normalize_path_copy(char *dst, const char *src)
380 {
381 char *dst0;
383 if (has_dos_drive_prefix(src)) {
384 *dst++ = *src++;
385 *dst++ = *src++;
386 }
387 dst0 = dst;
389 if (is_dir_sep(*src)) {
390 *dst++ = '/';
391 while (is_dir_sep(*src))
392 src++;
393 }
395 for (;;) {
396 char c = *src;
398 /*
399 * A path component that begins with . could be
400 * special:
401 * (1) "." and ends -- ignore and terminate.
402 * (2) "./" -- ignore them, eat slash and continue.
403 * (3) ".." and ends -- strip one and terminate.
404 * (4) "../" -- strip one, eat slash and continue.
405 */
406 if (c == '.') {
407 if (!src[1]) {
408 /* (1) */
409 src++;
410 } else if (is_dir_sep(src[1])) {
411 /* (2) */
412 src += 2;
413 while (is_dir_sep(*src))
414 src++;
415 continue;
416 } else if (src[1] == '.') {
417 if (!src[2]) {
418 /* (3) */
419 src += 2;
420 goto up_one;
421 } else if (is_dir_sep(src[2])) {
422 /* (4) */
423 src += 3;
424 while (is_dir_sep(*src))
425 src++;
426 goto up_one;
427 }
428 }
429 }
431 /* copy up to the next '/', and eat all '/' */
432 while ((c = *src++) != '\0' && !is_dir_sep(c))
433 *dst++ = c;
434 if (is_dir_sep(c)) {
435 *dst++ = '/';
436 while (is_dir_sep(c))
437 c = *src++;
438 src--;
439 } else if (!c)
440 break;
441 continue;
443 up_one:
444 /*
445 * dst0..dst is prefix portion, and dst[-1] is '/';
446 * go up one level.
447 */
448 dst--; /* go to trailing '/' */
449 if (dst <= dst0)
450 return -1;
451 /* Windows: dst[-1] cannot be backslash anymore */
452 while (dst0 < dst && dst[-1] != '/')
453 dst--;
454 }
455 *dst = '\0';
456 return 0;
457 }
459 /*
460 * path = Canonical absolute path
461 * prefix_list = Colon-separated list of absolute paths
462 *
463 * Determines, for each path in prefix_list, whether the "prefix" really
464 * is an ancestor directory of path. Returns the length of the longest
465 * ancestor directory, excluding any trailing slashes, or -1 if no prefix
466 * is an ancestor. (Note that this means 0 is returned if prefix_list is
467 * "/".) "/foo" is not considered an ancestor of "/foobar". Directories
468 * are not considered to be their own ancestors. path must be in a
469 * canonical form: empty components, or "." or ".." components are not
470 * allowed. prefix_list may be null, which is like "".
471 */
472 int longest_ancestor_length(const char *path, const char *prefix_list)
473 {
474 char buf[PATH_MAX+1];
475 const char *ceil, *colon;
476 int len, max_len = -1;
478 if (prefix_list == NULL || !strcmp(path, "/"))
479 return -1;
481 for (colon = ceil = prefix_list; *colon; ceil = colon+1) {
482 for (colon = ceil; *colon && *colon != PATH_SEP; colon++);
483 len = colon - ceil;
484 if (len == 0 || len > PATH_MAX || !is_absolute_path(ceil))
485 continue;
486 strlcpy(buf, ceil, len+1);
487 if (normalize_path_copy(buf, buf) < 0)
488 continue;
489 len = strlen(buf);
490 if (len > 0 && buf[len-1] == '/')
491 buf[--len] = '\0';
493 if (!strncmp(path, buf, len) &&
494 path[len] == '/' &&
495 len > max_len) {
496 max_len = len;
497 }
498 }
500 return max_len;
501 }