Eliminate an unnecessary chdir("..")
[git/git.git] / setup.c
1 #include "cache.h"
2 #include "dir.h"
3
4 static int inside_git_dir = -1;
5 static int inside_work_tree = -1;
6
7 static int sanitary_path_copy(char *dst, const char *src)
8 {
9 char *dst0 = dst;
10
11 if (*src == '/') {
12 *dst++ = '/';
13 while (*src == '/')
14 src++;
15 }
16
17 for (;;) {
18 char c = *src;
19
20 /*
21 * A path component that begins with . could be
22 * special:
23 * (1) "." and ends -- ignore and terminate.
24 * (2) "./" -- ignore them, eat slash and continue.
25 * (3) ".." and ends -- strip one and terminate.
26 * (4) "../" -- strip one, eat slash and continue.
27 */
28 if (c == '.') {
29 switch (src[1]) {
30 case '\0':
31 /* (1) */
32 src++;
33 break;
34 case '/':
35 /* (2) */
36 src += 2;
37 while (*src == '/')
38 src++;
39 continue;
40 case '.':
41 switch (src[2]) {
42 case '\0':
43 /* (3) */
44 src += 2;
45 goto up_one;
46 case '/':
47 /* (4) */
48 src += 3;
49 while (*src == '/')
50 src++;
51 goto up_one;
52 }
53 }
54 }
55
56 /* copy up to the next '/', and eat all '/' */
57 while ((c = *src++) != '\0' && c != '/')
58 *dst++ = c;
59 if (c == '/') {
60 *dst++ = c;
61 while (c == '/')
62 c = *src++;
63 src--;
64 } else if (!c)
65 break;
66 continue;
67
68 up_one:
69 /*
70 * dst0..dst is prefix portion, and dst[-1] is '/';
71 * go up one level.
72 */
73 dst -= 2; /* go past trailing '/' if any */
74 if (dst < dst0)
75 return -1;
76 while (1) {
77 if (dst <= dst0)
78 break;
79 c = *dst--;
80 if (c == '/') {
81 dst += 2;
82 break;
83 }
84 }
85 }
86 *dst = '\0';
87 return 0;
88 }
89
90 const char *prefix_path(const char *prefix, int len, const char *path)
91 {
92 const char *orig = path;
93 char *sanitized = xmalloc(len + strlen(path) + 1);
94 if (is_absolute_path(orig))
95 strcpy(sanitized, path);
96 else {
97 if (len)
98 memcpy(sanitized, prefix, len);
99 strcpy(sanitized + len, path);
100 }
101 if (sanitary_path_copy(sanitized, sanitized))
102 goto error_out;
103 if (is_absolute_path(orig)) {
104 const char *work_tree = get_git_work_tree();
105 size_t len = strlen(work_tree);
106 size_t total = strlen(sanitized) + 1;
107 if (strncmp(sanitized, work_tree, len) ||
108 (sanitized[len] != '\0' && sanitized[len] != '/')) {
109 error_out:
110 error("'%s' is outside repository", orig);
111 free(sanitized);
112 return NULL;
113 }
114 if (sanitized[len] == '/')
115 len++;
116 memmove(sanitized, sanitized + len, total - len);
117 }
118 return sanitized;
119 }
120
121 /*
122 * Unlike prefix_path, this should be used if the named file does
123 * not have to interact with index entry; i.e. name of a random file
124 * on the filesystem.
125 */
126 const char *prefix_filename(const char *pfx, int pfx_len, const char *arg)
127 {
128 static char path[PATH_MAX];
129 if (!pfx || !*pfx || is_absolute_path(arg))
130 return arg;
131 memcpy(path, pfx, pfx_len);
132 strcpy(path + pfx_len, arg);
133 return path;
134 }
135
136 /*
137 * Verify a filename that we got as an argument for a pathspec
138 * entry. Note that a filename that begins with "-" never verifies
139 * as true, because even if such a filename were to exist, we want
140 * it to be preceded by the "--" marker (or we want the user to
141 * use a format like "./-filename")
142 */
143 void verify_filename(const char *prefix, const char *arg)
144 {
145 const char *name;
146 struct stat st;
147
148 if (*arg == '-')
149 die("bad flag '%s' used after filename", arg);
150 name = prefix ? prefix_filename(prefix, strlen(prefix), arg) : arg;
151 if (!lstat(name, &st))
152 return;
153 if (errno == ENOENT)
154 die("ambiguous argument '%s': unknown revision or path not in the working tree.\n"
155 "Use '--' to separate paths from revisions", arg);
156 die("'%s': %s", arg, strerror(errno));
157 }
158
159 /*
160 * Opposite of the above: the command line did not have -- marker
161 * and we parsed the arg as a refname. It should not be interpretable
162 * as a filename.
163 */
164 void verify_non_filename(const char *prefix, const char *arg)
165 {
166 const char *name;
167 struct stat st;
168
169 if (!is_inside_work_tree() || is_inside_git_dir())
170 return;
171 if (*arg == '-')
172 return; /* flag */
173 name = prefix ? prefix_filename(prefix, strlen(prefix), arg) : arg;
174 if (!lstat(name, &st))
175 die("ambiguous argument '%s': both revision and filename\n"
176 "Use '--' to separate filenames from revisions", arg);
177 if (errno != ENOENT && errno != ENOTDIR)
178 die("'%s': %s", arg, strerror(errno));
179 }
180
181 const char **get_pathspec(const char *prefix, const char **pathspec)
182 {
183 const char *entry = *pathspec;
184 const char **src, **dst;
185 int prefixlen;
186
187 if (!prefix && !entry)
188 return NULL;
189
190 if (!entry) {
191 static const char *spec[2];
192 spec[0] = prefix;
193 spec[1] = NULL;
194 return spec;
195 }
196
197 /* Otherwise we have to re-write the entries.. */
198 src = pathspec;
199 dst = pathspec;
200 prefixlen = prefix ? strlen(prefix) : 0;
201 while (*src) {
202 const char *p = prefix_path(prefix, prefixlen, *src);
203 if (p)
204 *(dst++) = p;
205 else
206 exit(128); /* error message already given */
207 src++;
208 }
209 *dst = NULL;
210 if (!*pathspec)
211 return NULL;
212 return pathspec;
213 }
214
215 /*
216 * Test if it looks like we're at a git directory.
217 * We want to see:
218 *
219 * - either an objects/ directory _or_ the proper
220 * GIT_OBJECT_DIRECTORY environment variable
221 * - a refs/ directory
222 * - either a HEAD symlink or a HEAD file that is formatted as
223 * a proper "ref:", or a regular file HEAD that has a properly
224 * formatted sha1 object name.
225 */
226 static int is_git_directory(const char *suspect)
227 {
228 char path[PATH_MAX];
229 size_t len = strlen(suspect);
230
231 strcpy(path, suspect);
232 if (getenv(DB_ENVIRONMENT)) {
233 if (access(getenv(DB_ENVIRONMENT), X_OK))
234 return 0;
235 }
236 else {
237 strcpy(path + len, "/objects");
238 if (access(path, X_OK))
239 return 0;
240 }
241
242 strcpy(path + len, "/refs");
243 if (access(path, X_OK))
244 return 0;
245
246 strcpy(path + len, "/HEAD");
247 if (validate_headref(path))
248 return 0;
249
250 return 1;
251 }
252
253 int is_inside_git_dir(void)
254 {
255 if (inside_git_dir < 0)
256 inside_git_dir = is_inside_dir(get_git_dir());
257 return inside_git_dir;
258 }
259
260 int is_inside_work_tree(void)
261 {
262 if (inside_work_tree < 0)
263 inside_work_tree = is_inside_dir(get_git_work_tree());
264 return inside_work_tree;
265 }
266
267 /*
268 * set_work_tree() is only ever called if you set GIT_DIR explicitely.
269 * The old behaviour (which we retain here) is to set the work tree root
270 * to the cwd, unless overridden by the config, the command line, or
271 * GIT_WORK_TREE.
272 */
273 static const char *set_work_tree(const char *dir)
274 {
275 char buffer[PATH_MAX + 1];
276
277 if (!getcwd(buffer, sizeof(buffer)))
278 die ("Could not get the current working directory");
279 git_work_tree_cfg = xstrdup(buffer);
280 inside_work_tree = 1;
281
282 return NULL;
283 }
284
285 void setup_work_tree(void)
286 {
287 const char *work_tree, *git_dir;
288 static int initialized = 0;
289
290 if (initialized)
291 return;
292 work_tree = get_git_work_tree();
293 git_dir = get_git_dir();
294 if (!is_absolute_path(git_dir))
295 set_git_dir(make_absolute_path(git_dir));
296 if (!work_tree || chdir(work_tree))
297 die("This operation must be run in a work tree");
298 initialized = 1;
299 }
300
301 static int check_repository_format_gently(int *nongit_ok)
302 {
303 git_config(check_repository_format_version);
304 if (GIT_REPO_VERSION < repository_format_version) {
305 if (!nongit_ok)
306 die ("Expected git repo version <= %d, found %d",
307 GIT_REPO_VERSION, repository_format_version);
308 warning("Expected git repo version <= %d, found %d",
309 GIT_REPO_VERSION, repository_format_version);
310 warning("Please upgrade Git");
311 *nongit_ok = -1;
312 return -1;
313 }
314 return 0;
315 }
316
317 /*
318 * Try to read the location of the git directory from the .git file,
319 * return path to git directory if found.
320 */
321 const char *read_gitfile_gently(const char *path)
322 {
323 char *buf;
324 struct stat st;
325 int fd;
326 size_t len;
327
328 if (stat(path, &st))
329 return NULL;
330 if (!S_ISREG(st.st_mode))
331 return NULL;
332 fd = open(path, O_RDONLY);
333 if (fd < 0)
334 die("Error opening %s: %s", path, strerror(errno));
335 buf = xmalloc(st.st_size + 1);
336 len = read_in_full(fd, buf, st.st_size);
337 close(fd);
338 if (len != st.st_size)
339 die("Error reading %s", path);
340 buf[len] = '\0';
341 if (prefixcmp(buf, "gitdir: "))
342 die("Invalid gitfile format: %s", path);
343 while (buf[len - 1] == '\n' || buf[len - 1] == '\r')
344 len--;
345 if (len < 9)
346 die("No path in gitfile: %s", path);
347 buf[len] = '\0';
348 if (!is_git_directory(buf + 8))
349 die("Not a git repository: %s", buf + 8);
350 path = make_absolute_path(buf + 8);
351 free(buf);
352 return path;
353 }
354
355 /*
356 * We cannot decide in this function whether we are in the work tree or
357 * not, since the config can only be read _after_ this function was called.
358 */
359 const char *setup_git_directory_gently(int *nongit_ok)
360 {
361 const char *work_tree_env = getenv(GIT_WORK_TREE_ENVIRONMENT);
362 const char *env_ceiling_dirs = getenv(CEILING_DIRECTORIES_ENVIRONMENT);
363 static char cwd[PATH_MAX+1];
364 const char *gitdirenv;
365 const char *gitfile_dir;
366 int len, offset, ceil_offset;
367
368 /*
369 * Let's assume that we are in a git repository.
370 * If it turns out later that we are somewhere else, the value will be
371 * updated accordingly.
372 */
373 if (nongit_ok)
374 *nongit_ok = 0;
375
376 /*
377 * If GIT_DIR is set explicitly, we're not going
378 * to do any discovery, but we still do repository
379 * validation.
380 */
381 gitdirenv = getenv(GIT_DIR_ENVIRONMENT);
382 if (gitdirenv) {
383 if (PATH_MAX - 40 < strlen(gitdirenv))
384 die("'$%s' too big", GIT_DIR_ENVIRONMENT);
385 if (is_git_directory(gitdirenv)) {
386 static char buffer[1024 + 1];
387 const char *retval;
388
389 if (!work_tree_env) {
390 retval = set_work_tree(gitdirenv);
391 /* config may override worktree */
392 if (check_repository_format_gently(nongit_ok))
393 return NULL;
394 return retval;
395 }
396 if (check_repository_format_gently(nongit_ok))
397 return NULL;
398 retval = get_relative_cwd(buffer, sizeof(buffer) - 1,
399 get_git_work_tree());
400 if (!retval || !*retval)
401 return NULL;
402 set_git_dir(make_absolute_path(gitdirenv));
403 if (chdir(work_tree_env) < 0)
404 die ("Could not chdir to %s", work_tree_env);
405 strcat(buffer, "/");
406 return retval;
407 }
408 if (nongit_ok) {
409 *nongit_ok = 1;
410 return NULL;
411 }
412 die("Not a git repository: '%s'", gitdirenv);
413 }
414
415 if (!getcwd(cwd, sizeof(cwd)-1))
416 die("Unable to read current working directory");
417
418 ceil_offset = longest_ancestor_length(cwd, env_ceiling_dirs);
419
420 /*
421 * Test in the following order (relative to the cwd):
422 * - .git (file containing "gitdir: <path>")
423 * - .git/
424 * - ./ (bare)
425 * - ../.git
426 * - ../.git/
427 * - ../ (bare)
428 * - ../../.git/
429 * etc.
430 */
431 offset = len = strlen(cwd);
432 for (;;) {
433 gitfile_dir = read_gitfile_gently(DEFAULT_GIT_DIR_ENVIRONMENT);
434 if (gitfile_dir) {
435 if (set_git_dir(gitfile_dir))
436 die("Repository setup failed");
437 break;
438 }
439 if (is_git_directory(DEFAULT_GIT_DIR_ENVIRONMENT))
440 break;
441 if (is_git_directory(".")) {
442 inside_git_dir = 1;
443 if (!work_tree_env)
444 inside_work_tree = 0;
445 setenv(GIT_DIR_ENVIRONMENT, ".", 1);
446 check_repository_format_gently(nongit_ok);
447 return NULL;
448 }
449 while (--offset > ceil_offset && cwd[offset] != '/');
450 if (offset <= ceil_offset) {
451 if (nongit_ok) {
452 if (chdir(cwd))
453 die("Cannot come back to cwd");
454 *nongit_ok = 1;
455 return NULL;
456 }
457 die("Not a git repository");
458 }
459 chdir("..");
460 }
461
462 inside_git_dir = 0;
463 if (!work_tree_env)
464 inside_work_tree = 1;
465 git_work_tree_cfg = xstrndup(cwd, offset);
466 if (check_repository_format_gently(nongit_ok))
467 return NULL;
468 if (offset == len)
469 return NULL;
470
471 /* Make "offset" point to past the '/', and add a '/' at the end */
472 offset++;
473 cwd[len++] = '/';
474 cwd[len] = 0;
475 return cwd + offset;
476 }
477
478 int git_config_perm(const char *var, const char *value)
479 {
480 int i;
481 char *endptr;
482
483 if (value == NULL)
484 return PERM_GROUP;
485
486 if (!strcmp(value, "umask"))
487 return PERM_UMASK;
488 if (!strcmp(value, "group"))
489 return PERM_GROUP;
490 if (!strcmp(value, "all") ||
491 !strcmp(value, "world") ||
492 !strcmp(value, "everybody"))
493 return PERM_EVERYBODY;
494
495 /* Parse octal numbers */
496 i = strtol(value, &endptr, 8);
497
498 /* If not an octal number, maybe true/false? */
499 if (*endptr != 0)
500 return git_config_bool(var, value) ? PERM_GROUP : PERM_UMASK;
501
502 /*
503 * Treat values 0, 1 and 2 as compatibility cases, otherwise it is
504 * a chmod value.
505 */
506 switch (i) {
507 case PERM_UMASK: /* 0 */
508 return PERM_UMASK;
509 case OLD_PERM_GROUP: /* 1 */
510 return PERM_GROUP;
511 case OLD_PERM_EVERYBODY: /* 2 */
512 return PERM_EVERYBODY;
513 }
514
515 /* A filemode value was given: 0xxx */
516
517 if ((i & 0600) != 0600)
518 die("Problem with core.sharedRepository filemode value "
519 "(0%.3o).\nThe owner of files must always have "
520 "read and write permissions.", i);
521
522 /*
523 * Mask filemode value. Others can not get write permission.
524 * x flags for directories are handled separately.
525 */
526 return i & 0666;
527 }
528
529 int check_repository_format_version(const char *var, const char *value)
530 {
531 if (strcmp(var, "core.repositoryformatversion") == 0)
532 repository_format_version = git_config_int(var, value);
533 else if (strcmp(var, "core.sharedrepository") == 0)
534 shared_repository = git_config_perm(var, value);
535 else if (strcmp(var, "core.bare") == 0) {
536 is_bare_repository_cfg = git_config_bool(var, value);
537 if (is_bare_repository_cfg == 1)
538 inside_work_tree = -1;
539 } else if (strcmp(var, "core.worktree") == 0) {
540 if (!value)
541 return config_error_nonbool(var);
542 free(git_work_tree_cfg);
543 git_work_tree_cfg = xstrdup(value);
544 inside_work_tree = -1;
545 }
546 return 0;
547 }
548
549 int check_repository_format(void)
550 {
551 return check_repository_format_gently(NULL);
552 }
553
554 const char *setup_git_directory(void)
555 {
556 const char *retval = setup_git_directory_gently(NULL);
557
558 /* If the work tree is not the default one, recompute prefix */
559 if (inside_work_tree < 0) {
560 static char buffer[PATH_MAX + 1];
561 char *rel;
562 if (retval && chdir(retval))
563 die ("Could not jump back into original cwd");
564 rel = get_relative_cwd(buffer, PATH_MAX, get_git_work_tree());
565 return rel && *rel ? strcat(rel, "/") : NULL;
566 }
567
568 return retval;
569 }