Move sanitary_path_copy() to path.c and rename it to normalize_path_copy()
[git/git.git] / path.c
CommitLineData
26c8a533
LT
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
26c8a533
LT
15static char bad_path[] = "/bad-path/";
16
e7676d2f
LT
17static char *get_pathname(void)
18{
19 static char pathname_array[4][PATH_MAX];
20 static int index;
21 return pathname_array[3 & ++index];
22}
23
26c8a533
LT
24static 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}
34
108bebea
AR
35char *mksnpath(char *buf, size_t n, const char *fmt, ...)
36{
37 va_list args;
38 unsigned len;
39
40 va_start(args, fmt);
41 len = vsnprintf(buf, n, fmt, args);
42 va_end(args);
43 if (len >= n) {
9db56f71 44 strlcpy(buf, bad_path, n);
108bebea
AR
45 return buf;
46 }
47 return cleanup_path(buf);
48}
49
aba13e7c 50static char *git_vsnpath(char *buf, size_t n, const char *fmt, va_list args)
fe2d7776
AR
51{
52 const char *git_dir = get_git_dir();
fe2d7776
AR
53 size_t len;
54
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++] = '/';
fe2d7776 61 len += vsnprintf(buf + len, n - len, fmt, args);
fe2d7776
AR
62 if (len >= n)
63 goto bad;
64 return cleanup_path(buf);
65bad:
9db56f71 66 strlcpy(buf, bad_path, n);
fe2d7776
AR
67 return buf;
68}
69
aba13e7c
AR
70char *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}
78
79char *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}
88
26c8a533
LT
89char *mkpath(const char *fmt, ...)
90{
91 va_list args;
92 unsigned len;
e7676d2f 93 char *pathname = get_pathname();
26c8a533
LT
94
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}
102
103char *git_path(const char *fmt, ...)
104{
5da1606d 105 const char *git_dir = get_git_dir();
e7676d2f 106 char *pathname = get_pathname();
26c8a533
LT
107 va_list args;
108 unsigned len;
109
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}
f2db68ed
HE
123
124
125/* git_mkstemp() - create tmp file honoring TMPDIR variable */
126int git_mkstemp(char *path, size_t len, const char *template)
127{
e7a7be88
JH
128 const char *tmp;
129 size_t n;
130
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;
35c3c629 138 }
f2db68ed
HE
139 return mkstemp(path);
140}
141
142
c847f537 143int validate_headref(const char *path)
0870ca7f
JH
144{
145 struct stat st;
146 char *buf, buffer[256];
c847f537 147 unsigned char sha1[20];
0104ca09
HO
148 int fd;
149 ssize_t len;
0870ca7f
JH
150
151 if (lstat(path, &st) < 0)
152 return -1;
153
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 }
161
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;
93d26e4c 168 len = read_in_full(fd, buffer, sizeof(buffer)-1);
0870ca7f
JH
169 close(fd);
170
171 /*
172 * Is it a symbolic ref?
173 */
c847f537 174 if (len < 4)
0870ca7f 175 return -1;
c847f537
JH
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
185 /*
186 * Is this a detached HEAD?
187 */
188 if (!get_sha1_hex(buffer, sha1))
0870ca7f 189 return 0;
c847f537 190
0870ca7f
JH
191 return -1;
192}
193
d79374c7 194static char *user_path(char *buf, char *path, int sz)
54f4b874 195{
d79374c7
JH
196 struct passwd *pw;
197 char *slash;
198 int len, baselen;
54f4b874 199
d79374c7
JH
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 = '/';
54f4b874 212 }
d79374c7
JH
213 else
214 pw = getpwnam(path);
54f4b874 215 }
d79374c7
JH
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;
54f4b874
AE
231}
232
d79374c7
JH
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 */
54f4b874
AE
257char *enter_repo(char *path, int strict)
258{
d79374c7
JH
259 static char used_path[PATH_MAX];
260 static char validated_path[PATH_MAX];
261
262 if (!path)
54f4b874
AE
263 return NULL;
264
d79374c7
JH
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)
54f4b874 276 return NULL;
d79374c7
JH
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))
0870ca7f 298 return NULL;
d79374c7 299 path = validated_path;
0870ca7f 300 }
d79374c7
JH
301 else if (chdir(path))
302 return NULL;
54f4b874 303
d79374c7 304 if (access("objects", X_OK) == 0 && access("refs", X_OK) == 0 &&
c847f537 305 validate_headref("HEAD") == 0) {
7627943a 306 setenv(GIT_DIR_ENVIRONMENT, ".", 1);
1644162a 307 check_repository_format();
d79374c7 308 return path;
54f4b874
AE
309 }
310
311 return NULL;
312}
138086a7
JH
313
314int adjust_shared_perm(const char *path)
315{
316 struct stat st;
317 int mode;
318
319 if (!shared_repository)
320 return 0;
321 if (lstat(path, &st) < 0)
322 return -1;
323 mode = st.st_mode;
06cbe855
HO
324
325 if (shared_repository) {
326 int tweak = shared_repository;
327 if (!(mode & S_IWUSR))
328 tweak &= ~0222;
8c6202d8 329 mode |= tweak;
06cbe855
HO
330 } else {
331 /* Preserve old PERM_UMASK behaviour */
332 if (mode & S_IWUSR)
333 mode |= S_IWGRP;
334 }
335
336 if (S_ISDIR(mode)) {
81a24b52 337 mode |= FORCE_DIR_SET_GID;
06cbe855
HO
338
339 /* Copy read bits to execute bits */
340 mode |= (shared_repository & 0444) >> 2;
341 }
342
fe732ede 343 if ((mode & st.st_mode) != mode && chmod(path, mode) < 0)
138086a7
JH
344 return -2;
345 return 0;
346}
e5392c51 347
044bbbcb
LT
348const 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}
ae299be0
DR
364
365/*
366 * path = absolute path
367 * buf = buffer of at least max(2, strlen(path)+1) bytes
368 * It is okay if buf == path, but they should not overlap otherwise.
369 *
370 * Performs the following normalizations on path, storing the result in buf:
371 * - Removes trailing slashes.
372 * - Removes empty components.
373 * - Removes "." components.
374 * - Removes ".." components, and the components the precede them.
375 * "" and paths that contain only slashes are normalized to "/".
376 * Returns the length of the output.
377 *
378 * Note that this function is purely textual. It does not follow symlinks,
379 * verify the existence of the path, or make any system calls.
380 */
381int normalize_absolute_path(char *buf, const char *path)
382{
383 const char *comp_start = path, *comp_end = path;
384 char *dst = buf;
385 int comp_len;
386 assert(buf);
387 assert(path);
388
389 while (*comp_start) {
390 assert(*comp_start == '/');
391 while (*++comp_end && *comp_end != '/')
392 ; /* nothing */
393 comp_len = comp_end - comp_start;
394
395 if (!strncmp("/", comp_start, comp_len) ||
396 !strncmp("/.", comp_start, comp_len))
397 goto next;
398
399 if (!strncmp("/..", comp_start, comp_len)) {
400 while (dst > buf && *--dst != '/')
401 ; /* nothing */
402 goto next;
403 }
404
1442171b 405 memmove(dst, comp_start, comp_len);
ae299be0
DR
406 dst += comp_len;
407 next:
408 comp_start = comp_end;
409 }
410
411 if (dst == buf)
412 *dst++ = '/';
413
414 *dst = '\0';
415 return dst - buf;
416}
0454dd93 417
f3cad0ad
JS
418int normalize_path_copy(char *dst, const char *src)
419{
420 char *dst0;
421
422 if (has_dos_drive_prefix(src)) {
423 *dst++ = *src++;
424 *dst++ = *src++;
425 }
426 dst0 = dst;
427
428 if (is_dir_sep(*src)) {
429 *dst++ = '/';
430 while (is_dir_sep(*src))
431 src++;
432 }
433
434 for (;;) {
435 char c = *src;
436
437 /*
438 * A path component that begins with . could be
439 * special:
440 * (1) "." and ends -- ignore and terminate.
441 * (2) "./" -- ignore them, eat slash and continue.
442 * (3) ".." and ends -- strip one and terminate.
443 * (4) "../" -- strip one, eat slash and continue.
444 */
445 if (c == '.') {
446 if (!src[1]) {
447 /* (1) */
448 src++;
449 } else if (is_dir_sep(src[1])) {
450 /* (2) */
451 src += 2;
452 while (is_dir_sep(*src))
453 src++;
454 continue;
455 } else if (src[1] == '.') {
456 if (!src[2]) {
457 /* (3) */
458 src += 2;
459 goto up_one;
460 } else if (is_dir_sep(src[2])) {
461 /* (4) */
462 src += 3;
463 while (is_dir_sep(*src))
464 src++;
465 goto up_one;
466 }
467 }
468 }
469
470 /* copy up to the next '/', and eat all '/' */
471 while ((c = *src++) != '\0' && !is_dir_sep(c))
472 *dst++ = c;
473 if (is_dir_sep(c)) {
474 *dst++ = '/';
475 while (is_dir_sep(c))
476 c = *src++;
477 src--;
478 } else if (!c)
479 break;
480 continue;
481
482 up_one:
483 /*
484 * dst0..dst is prefix portion, and dst[-1] is '/';
485 * go up one level.
486 */
487 dst -= 2; /* go past trailing '/' if any */
488 if (dst < dst0)
489 return -1;
490 while (1) {
491 if (dst <= dst0)
492 break;
493 c = *dst--;
494 if (c == '/') { /* MinGW: cannot be '\\' anymore */
495 dst += 2;
496 break;
497 }
498 }
499 }
500 *dst = '\0';
501 return 0;
502}
503
0454dd93
DR
504/*
505 * path = Canonical absolute path
506 * prefix_list = Colon-separated list of absolute paths
507 *
2860b57a 508 * Determines, for each path in prefix_list, whether the "prefix" really
0454dd93
DR
509 * is an ancestor directory of path. Returns the length of the longest
510 * ancestor directory, excluding any trailing slashes, or -1 if no prefix
511 * is an ancestor. (Note that this means 0 is returned if prefix_list is
512 * "/".) "/foo" is not considered an ancestor of "/foobar". Directories
513 * are not considered to be their own ancestors. path must be in a
514 * canonical form: empty components, or "." or ".." components are not
515 * allowed. prefix_list may be null, which is like "".
516 */
517int longest_ancestor_length(const char *path, const char *prefix_list)
518{
519 char buf[PATH_MAX+1];
520 const char *ceil, *colon;
521 int len, max_len = -1;
522
523 if (prefix_list == NULL || !strcmp(path, "/"))
524 return -1;
525
526 for (colon = ceil = prefix_list; *colon; ceil = colon+1) {
527 for (colon = ceil; *colon && *colon != ':'; colon++);
528 len = colon - ceil;
529 if (len == 0 || len > PATH_MAX || !is_absolute_path(ceil))
530 continue;
531 strlcpy(buf, ceil, len+1);
532 len = normalize_absolute_path(buf, buf);
533 /* Strip "trailing slashes" from "/". */
534 if (len == 1)
535 len = 0;
536
537 if (!strncmp(path, buf, len) &&
538 path[len] == '/' &&
539 len > max_len) {
540 max_len = len;
541 }
542 }
543
544 return max_len;
545}