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9eb977db KS |
1 | /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ |
2 | ||
3 | /*** | |
4 | This file is part of systemd. | |
5 | ||
6 | Copyright 2010-2012 Lennart Poettering | |
7 | ||
8 | systemd is free software; you can redistribute it and/or modify it | |
9 | under the terms of the GNU Lesser General Public License as published by | |
10 | the Free Software Foundation; either version 2.1 of the License, or | |
11 | (at your option) any later version. | |
12 | ||
13 | systemd is distributed in the hope that it will be useful, but | |
14 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
16 | Lesser General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU Lesser General Public License | |
19 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
20 | ***/ | |
21 | ||
9eb977db | 22 | #include <errno.h> |
9eb977db | 23 | #include <fcntl.h> |
07630cea LP |
24 | #include <stdio.h> |
25 | #include <stdlib.h> | |
26 | #include <string.h> | |
9eb977db | 27 | #include <sys/statvfs.h> |
07630cea | 28 | #include <unistd.h> |
9eb977db | 29 | |
07630cea | 30 | #include "fileio.h" |
9eb977db | 31 | #include "log.h" |
07630cea LP |
32 | #include "macro.h" |
33 | #include "missing.h" | |
34 | #include "string-util.h" | |
9eb977db | 35 | #include "strv.h" |
07630cea | 36 | #include "util.h" |
9eb977db KS |
37 | #include "path-util.h" |
38 | ||
39 | bool path_is_absolute(const char *p) { | |
40 | return p[0] == '/'; | |
41 | } | |
42 | ||
43 | bool is_path(const char *p) { | |
44 | return !!strchr(p, '/'); | |
45 | } | |
46 | ||
9eb977db KS |
47 | int path_get_parent(const char *path, char **_r) { |
48 | const char *e, *a = NULL, *b = NULL, *p; | |
49 | char *r; | |
50 | bool slash = false; | |
51 | ||
52 | assert(path); | |
53 | assert(_r); | |
54 | ||
55 | if (!*path) | |
56 | return -EINVAL; | |
57 | ||
58 | for (e = path; *e; e++) { | |
59 | ||
60 | if (!slash && *e == '/') { | |
61 | a = b; | |
62 | b = e; | |
63 | slash = true; | |
64 | } else if (slash && *e != '/') | |
65 | slash = false; | |
66 | } | |
67 | ||
68 | if (*(e-1) == '/') | |
69 | p = a; | |
70 | else | |
71 | p = b; | |
72 | ||
73 | if (!p) | |
74 | return -EINVAL; | |
75 | ||
76 | if (p == path) | |
77 | r = strdup("/"); | |
78 | else | |
79 | r = strndup(path, p-path); | |
80 | ||
81 | if (!r) | |
82 | return -ENOMEM; | |
83 | ||
84 | *_r = r; | |
85 | return 0; | |
86 | } | |
87 | ||
0f474365 | 88 | int path_split_and_make_absolute(const char *p, char ***ret) { |
9eb977db | 89 | char **l; |
0f474365 LP |
90 | int r; |
91 | ||
9eb977db | 92 | assert(p); |
0f474365 | 93 | assert(ret); |
9eb977db | 94 | |
116cc028 ZJS |
95 | l = strv_split(p, ":"); |
96 | if (!l) | |
9eb977db KS |
97 | return NULL; |
98 | ||
0f474365 LP |
99 | r = path_strv_make_absolute_cwd(l); |
100 | if (r < 0) { | |
9eb977db | 101 | strv_free(l); |
0f474365 | 102 | return r; |
9eb977db KS |
103 | } |
104 | ||
0f474365 LP |
105 | *ret = l; |
106 | return r; | |
9eb977db KS |
107 | } |
108 | ||
109 | char *path_make_absolute(const char *p, const char *prefix) { | |
110 | assert(p); | |
111 | ||
112 | /* Makes every item in the list an absolute path by prepending | |
113 | * the prefix, if specified and necessary */ | |
114 | ||
115 | if (path_is_absolute(p) || !prefix) | |
116 | return strdup(p); | |
117 | ||
b7def684 | 118 | return strjoin(prefix, "/", p, NULL); |
9eb977db KS |
119 | } |
120 | ||
0f474365 LP |
121 | int path_make_absolute_cwd(const char *p, char **ret) { |
122 | char *c; | |
9eb977db KS |
123 | |
124 | assert(p); | |
0f474365 | 125 | assert(ret); |
9eb977db KS |
126 | |
127 | /* Similar to path_make_absolute(), but prefixes with the | |
128 | * current working directory. */ | |
129 | ||
130 | if (path_is_absolute(p)) | |
0f474365 LP |
131 | c = strdup(p); |
132 | else { | |
133 | _cleanup_free_ char *cwd = NULL; | |
9eb977db | 134 | |
0f474365 LP |
135 | cwd = get_current_dir_name(); |
136 | if (!cwd) | |
137 | return -errno; | |
138 | ||
139 | c = strjoin(cwd, "/", p, NULL); | |
140 | } | |
141 | if (!c) | |
142 | return -ENOMEM; | |
9eb977db | 143 | |
0f474365 LP |
144 | *ret = c; |
145 | return 0; | |
9eb977db KS |
146 | } |
147 | ||
7cb9c51c TK |
148 | int path_make_relative(const char *from_dir, const char *to_path, char **_r) { |
149 | char *r, *p; | |
150 | unsigned n_parents; | |
7cb9c51c TK |
151 | |
152 | assert(from_dir); | |
153 | assert(to_path); | |
154 | assert(_r); | |
155 | ||
156 | /* Strips the common part, and adds ".." elements as necessary. */ | |
157 | ||
158 | if (!path_is_absolute(from_dir)) | |
159 | return -EINVAL; | |
160 | ||
161 | if (!path_is_absolute(to_path)) | |
162 | return -EINVAL; | |
163 | ||
164 | /* Skip the common part. */ | |
165 | for (;;) { | |
166 | size_t a; | |
167 | size_t b; | |
168 | ||
169 | from_dir += strspn(from_dir, "/"); | |
170 | to_path += strspn(to_path, "/"); | |
171 | ||
172 | if (!*from_dir) { | |
173 | if (!*to_path) | |
174 | /* from_dir equals to_path. */ | |
175 | r = strdup("."); | |
176 | else | |
177 | /* from_dir is a parent directory of to_path. */ | |
178 | r = strdup(to_path); | |
179 | ||
180 | if (!r) | |
181 | return -ENOMEM; | |
182 | ||
5216f599 TK |
183 | path_kill_slashes(r); |
184 | ||
7cb9c51c TK |
185 | *_r = r; |
186 | return 0; | |
187 | } | |
188 | ||
189 | if (!*to_path) | |
190 | break; | |
191 | ||
192 | a = strcspn(from_dir, "/"); | |
193 | b = strcspn(to_path, "/"); | |
194 | ||
195 | if (a != b) | |
196 | break; | |
197 | ||
198 | if (memcmp(from_dir, to_path, a) != 0) | |
199 | break; | |
200 | ||
201 | from_dir += a; | |
202 | to_path += b; | |
203 | } | |
204 | ||
205 | /* If we're here, then "from_dir" has one or more elements that need to | |
206 | * be replaced with "..". */ | |
207 | ||
208 | /* Count the number of necessary ".." elements. */ | |
209 | for (n_parents = 0;;) { | |
210 | from_dir += strspn(from_dir, "/"); | |
211 | ||
212 | if (!*from_dir) | |
213 | break; | |
214 | ||
215 | from_dir += strcspn(from_dir, "/"); | |
216 | n_parents++; | |
217 | } | |
218 | ||
5216f599 | 219 | r = malloc(n_parents * 3 + strlen(to_path) + 1); |
7cb9c51c TK |
220 | if (!r) |
221 | return -ENOMEM; | |
222 | ||
223 | for (p = r; n_parents > 0; n_parents--, p += 3) | |
224 | memcpy(p, "../", 3); | |
225 | ||
5216f599 TK |
226 | strcpy(p, to_path); |
227 | path_kill_slashes(r); | |
7cb9c51c TK |
228 | |
229 | *_r = r; | |
230 | return 0; | |
231 | } | |
232 | ||
0f474365 | 233 | int path_strv_make_absolute_cwd(char **l) { |
9eb977db | 234 | char **s; |
0f474365 | 235 | int r; |
9eb977db KS |
236 | |
237 | /* Goes through every item in the string list and makes it | |
238 | * absolute. This works in place and won't rollback any | |
239 | * changes on failure. */ | |
240 | ||
241 | STRV_FOREACH(s, l) { | |
242 | char *t; | |
243 | ||
0f474365 LP |
244 | r = path_make_absolute_cwd(*s, &t); |
245 | if (r < 0) | |
246 | return r; | |
9eb977db KS |
247 | |
248 | free(*s); | |
249 | *s = t; | |
250 | } | |
251 | ||
0f474365 | 252 | return 0; |
9eb977db KS |
253 | } |
254 | ||
7d8da2c9 | 255 | char **path_strv_resolve(char **l, const char *prefix) { |
9eb977db KS |
256 | char **s; |
257 | unsigned k = 0; | |
258 | bool enomem = false; | |
259 | ||
260 | if (strv_isempty(l)) | |
261 | return l; | |
262 | ||
263 | /* Goes through every item in the string list and canonicalize | |
264 | * the path. This works in place and won't rollback any | |
265 | * changes on failure. */ | |
266 | ||
267 | STRV_FOREACH(s, l) { | |
268 | char *t, *u; | |
12ed81d9 | 269 | _cleanup_free_ char *orig = NULL; |
9eb977db | 270 | |
12ed81d9 ZJS |
271 | if (!path_is_absolute(*s)) { |
272 | free(*s); | |
9eb977db | 273 | continue; |
12ed81d9 | 274 | } |
112cfb18 MM |
275 | |
276 | if (prefix) { | |
12ed81d9 ZJS |
277 | orig = *s; |
278 | t = strappend(prefix, orig); | |
112cfb18 MM |
279 | if (!t) { |
280 | enomem = true; | |
281 | continue; | |
282 | } | |
12ed81d9 | 283 | } else |
112cfb18 | 284 | t = *s; |
9eb977db KS |
285 | |
286 | errno = 0; | |
287 | u = canonicalize_file_name(t); | |
9eb977db | 288 | if (!u) { |
12ed81d9 ZJS |
289 | if (errno == ENOENT) { |
290 | if (prefix) { | |
291 | u = orig; | |
292 | orig = NULL; | |
293 | free(t); | |
294 | } else | |
295 | u = t; | |
296 | } else { | |
874310b7 | 297 | free(t); |
112cfb18 | 298 | if (errno == ENOMEM || errno == 0) |
874310b7 ZJS |
299 | enomem = true; |
300 | ||
301 | continue; | |
302 | } | |
12ed81d9 ZJS |
303 | } else if (prefix) { |
304 | char *x; | |
305 | ||
306 | free(t); | |
307 | x = path_startswith(u, prefix); | |
308 | if (x) { | |
309 | /* restore the slash if it was lost */ | |
310 | if (!startswith(x, "/")) | |
311 | *(--x) = '/'; | |
312 | ||
313 | t = strdup(x); | |
314 | free(u); | |
315 | if (!t) { | |
316 | enomem = true; | |
317 | continue; | |
318 | } | |
319 | u = t; | |
320 | } else { | |
321 | /* canonicalized path goes outside of | |
322 | * prefix, keep the original path instead */ | |
3542eac7 | 323 | free(u); |
12ed81d9 ZJS |
324 | u = orig; |
325 | orig = NULL; | |
326 | } | |
91a6489d LP |
327 | } else |
328 | free(t); | |
9eb977db KS |
329 | |
330 | l[k++] = u; | |
331 | } | |
332 | ||
333 | l[k] = NULL; | |
334 | ||
335 | if (enomem) | |
336 | return NULL; | |
337 | ||
338 | return l; | |
339 | } | |
340 | ||
7d8da2c9 | 341 | char **path_strv_resolve_uniq(char **l, const char *prefix) { |
112cfb18 | 342 | |
fabe5c0e LP |
343 | if (strv_isempty(l)) |
344 | return l; | |
345 | ||
7d8da2c9 | 346 | if (!path_strv_resolve(l, prefix)) |
fabe5c0e LP |
347 | return NULL; |
348 | ||
349 | return strv_uniq(l); | |
350 | } | |
351 | ||
9eb977db KS |
352 | char *path_kill_slashes(char *path) { |
353 | char *f, *t; | |
354 | bool slash = false; | |
355 | ||
356 | /* Removes redundant inner and trailing slashes. Modifies the | |
357 | * passed string in-place. | |
358 | * | |
359 | * ///foo///bar/ becomes /foo/bar | |
360 | */ | |
361 | ||
362 | for (f = path, t = path; *f; f++) { | |
363 | ||
364 | if (*f == '/') { | |
365 | slash = true; | |
366 | continue; | |
367 | } | |
368 | ||
369 | if (slash) { | |
370 | slash = false; | |
371 | *(t++) = '/'; | |
372 | } | |
373 | ||
374 | *(t++) = *f; | |
375 | } | |
376 | ||
377 | /* Special rule, if we are talking of the root directory, a | |
378 | trailing slash is good */ | |
379 | ||
380 | if (t == path && slash) | |
381 | *(t++) = '/'; | |
382 | ||
383 | *t = 0; | |
384 | return path; | |
385 | } | |
386 | ||
424a19f8 | 387 | char* path_startswith(const char *path, const char *prefix) { |
9eb977db KS |
388 | assert(path); |
389 | assert(prefix); | |
390 | ||
391 | if ((path[0] == '/') != (prefix[0] == '/')) | |
424a19f8 | 392 | return NULL; |
9eb977db KS |
393 | |
394 | for (;;) { | |
395 | size_t a, b; | |
396 | ||
397 | path += strspn(path, "/"); | |
398 | prefix += strspn(prefix, "/"); | |
399 | ||
400 | if (*prefix == 0) | |
424a19f8 | 401 | return (char*) path; |
9eb977db KS |
402 | |
403 | if (*path == 0) | |
424a19f8 | 404 | return NULL; |
9eb977db KS |
405 | |
406 | a = strcspn(path, "/"); | |
407 | b = strcspn(prefix, "/"); | |
408 | ||
409 | if (a != b) | |
424a19f8 | 410 | return NULL; |
9eb977db KS |
411 | |
412 | if (memcmp(path, prefix, a) != 0) | |
424a19f8 | 413 | return NULL; |
9eb977db KS |
414 | |
415 | path += a; | |
416 | prefix += b; | |
417 | } | |
418 | } | |
419 | ||
2230852b MS |
420 | int path_compare(const char *a, const char *b) { |
421 | int d; | |
422 | ||
9eb977db KS |
423 | assert(a); |
424 | assert(b); | |
425 | ||
2230852b MS |
426 | /* A relative path and an abolute path must not compare as equal. |
427 | * Which one is sorted before the other does not really matter. | |
428 | * Here a relative path is ordered before an absolute path. */ | |
429 | d = (a[0] == '/') - (b[0] == '/'); | |
430 | if (d) | |
431 | return d; | |
9eb977db KS |
432 | |
433 | for (;;) { | |
434 | size_t j, k; | |
435 | ||
436 | a += strspn(a, "/"); | |
437 | b += strspn(b, "/"); | |
438 | ||
439 | if (*a == 0 && *b == 0) | |
2230852b | 440 | return 0; |
9eb977db | 441 | |
2230852b MS |
442 | /* Order prefixes first: "/foo" before "/foo/bar" */ |
443 | if (*a == 0) | |
444 | return -1; | |
445 | if (*b == 0) | |
446 | return 1; | |
9eb977db KS |
447 | |
448 | j = strcspn(a, "/"); | |
449 | k = strcspn(b, "/"); | |
450 | ||
2230852b MS |
451 | /* Alphabetical sort: "/foo/aaa" before "/foo/b" */ |
452 | d = memcmp(a, b, MIN(j, k)); | |
453 | if (d) | |
454 | return (d > 0) - (d < 0); /* sign of d */ | |
9eb977db | 455 | |
2230852b MS |
456 | /* Sort "/foo/a" before "/foo/aaa" */ |
457 | d = (j > k) - (j < k); /* sign of (j - k) */ | |
458 | if (d) | |
459 | return d; | |
9eb977db KS |
460 | |
461 | a += j; | |
462 | b += k; | |
463 | } | |
464 | } | |
465 | ||
2230852b MS |
466 | bool path_equal(const char *a, const char *b) { |
467 | return path_compare(a, b) == 0; | |
468 | } | |
469 | ||
c78e47a6 MS |
470 | bool path_equal_or_files_same(const char *a, const char *b) { |
471 | return path_equal(a, b) || files_same(a, b) > 0; | |
472 | } | |
473 | ||
0c6ea3a4 ZJS |
474 | char* path_join(const char *root, const char *path, const char *rest) { |
475 | assert(path); | |
476 | ||
477 | if (!isempty(root)) | |
bc854dc7 | 478 | return strjoin(root, endswith(root, "/") ? "" : "/", |
0c6ea3a4 | 479 | path[0] == '/' ? path+1 : path, |
bc854dc7 | 480 | rest ? (endswith(path, "/") ? "" : "/") : NULL, |
0c6ea3a4 ZJS |
481 | rest && rest[0] == '/' ? rest+1 : rest, |
482 | NULL); | |
483 | else | |
484 | return strjoin(path, | |
bc854dc7 | 485 | rest ? (endswith(path, "/") ? "" : "/") : NULL, |
0c6ea3a4 ZJS |
486 | rest && rest[0] == '/' ? rest+1 : rest, |
487 | NULL); | |
488 | } | |
489 | ||
3f72b427 LP |
490 | static int fd_fdinfo_mnt_id(int fd, const char *filename, int flags, int *mnt_id) { |
491 | char path[strlen("/proc/self/fdinfo/") + DECIMAL_STR_MAX(int)]; | |
492 | _cleanup_free_ char *fdinfo = NULL; | |
493 | _cleanup_close_ int subfd = -1; | |
494 | char *p; | |
495 | int r; | |
496 | ||
497 | if ((flags & AT_EMPTY_PATH) && isempty(filename)) | |
498 | xsprintf(path, "/proc/self/fdinfo/%i", fd); | |
499 | else { | |
500 | subfd = openat(fd, filename, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_PATH); | |
501 | if (subfd < 0) | |
502 | return -errno; | |
503 | ||
504 | xsprintf(path, "/proc/self/fdinfo/%i", subfd); | |
505 | } | |
506 | ||
507 | r = read_full_file(path, &fdinfo, NULL); | |
508 | if (r == -ENOENT) /* The fdinfo directory is a relatively new addition */ | |
509 | return -EOPNOTSUPP; | |
510 | if (r < 0) | |
511 | return -errno; | |
512 | ||
513 | p = startswith(fdinfo, "mnt_id:"); | |
514 | if (!p) { | |
515 | p = strstr(fdinfo, "\nmnt_id:"); | |
516 | if (!p) /* The mnt_id field is a relatively new addition */ | |
517 | return -EOPNOTSUPP; | |
518 | ||
519 | p += 8; | |
520 | } | |
521 | ||
522 | p += strspn(p, WHITESPACE); | |
523 | p[strcspn(p, WHITESPACE)] = 0; | |
524 | ||
525 | return safe_atoi(p, mnt_id); | |
526 | } | |
527 | ||
5d409034 | 528 | int fd_is_mount_point(int fd, const char *filename, int flags) { |
05d990ef | 529 | union file_handle_union h = FILE_HANDLE_INIT, h_parent = FILE_HANDLE_INIT; |
e40872fc | 530 | int mount_id = -1, mount_id_parent = -1; |
84317788 | 531 | bool nosupp = false, check_st_dev = true; |
1640a0b6 | 532 | struct stat a, b; |
21749924 | 533 | int r; |
9eb977db | 534 | |
05d990ef | 535 | assert(fd >= 0); |
5d409034 | 536 | assert(filename); |
05d990ef | 537 | |
3f72b427 LP |
538 | /* First we will try the name_to_handle_at() syscall, which |
539 | * tells us the mount id and an opaque file "handle". It is | |
540 | * not supported everywhere though (kernel compile-time | |
541 | * option, not all file systems are hooked up). If it works | |
542 | * the mount id is usually good enough to tell us whether | |
543 | * something is a mount point. | |
544 | * | |
545 | * If that didn't work we will try to read the mount id from | |
546 | * /proc/self/fdinfo/<fd>. This is almost as good as | |
af86c440 | 547 | * name_to_handle_at(), however, does not return the |
3f72b427 LP |
548 | * opaque file handle. The opaque file handle is pretty useful |
549 | * to detect the root directory, which we should always | |
550 | * consider a mount point. Hence we use this only as | |
551 | * fallback. Exporting the mnt_id in fdinfo is a pretty recent | |
552 | * kernel addition. | |
553 | * | |
554 | * As last fallback we do traditional fstat() based st_dev | |
555 | * comparisons. This is how things were traditionally done, | |
556 | * but unionfs breaks breaks this since it exposes file | |
557 | * systems with a variety of st_dev reported. Also, btrfs | |
558 | * subvolumes have different st_dev, even though they aren't | |
559 | * real mounts of their own. */ | |
cde9cb34 | 560 | |
5d409034 | 561 | r = name_to_handle_at(fd, filename, &h.handle, &mount_id, flags); |
9eb977db | 562 | if (r < 0) { |
e40872fc DR |
563 | if (errno == ENOSYS) |
564 | /* This kernel does not support name_to_handle_at() | |
3f72b427 LP |
565 | * fall back to simpler logic. */ |
566 | goto fallback_fdinfo; | |
e40872fc | 567 | else if (errno == EOPNOTSUPP) |
fa125f4e | 568 | /* This kernel or file system does not support |
f25afeb6 LP |
569 | * name_to_handle_at(), hence let's see if the |
570 | * upper fs supports it (in which case it is a | |
571 | * mount point), otherwise fallback to the | |
1640a0b6 | 572 | * traditional stat() logic */ |
6feeeab0 | 573 | nosupp = true; |
6feeeab0 ZJS |
574 | else |
575 | return -errno; | |
9eb977db KS |
576 | } |
577 | ||
5d409034 | 578 | r = name_to_handle_at(fd, "", &h_parent.handle, &mount_id_parent, AT_EMPTY_PATH); |
f25afeb6 LP |
579 | if (r < 0) { |
580 | if (errno == EOPNOTSUPP) { | |
6feeeab0 ZJS |
581 | if (nosupp) |
582 | /* Neither parent nor child do name_to_handle_at()? | |
583 | We have no choice but to fall back. */ | |
3f72b427 | 584 | goto fallback_fdinfo; |
6feeeab0 | 585 | else |
f25afeb6 LP |
586 | /* The parent can't do name_to_handle_at() but the |
587 | * directory we are interested in can? | |
6feeeab0 ZJS |
588 | * If so, it must be a mount point. */ |
589 | return 1; | |
f25afeb6 | 590 | } else |
6feeeab0 | 591 | return -errno; |
3f72b427 LP |
592 | } |
593 | ||
594 | /* The parent can do name_to_handle_at() but the | |
595 | * directory we are interested in can't? If so, it | |
596 | * must be a mount point. */ | |
597 | if (nosupp) | |
8f06b239 | 598 | return 1; |
05d990ef | 599 | |
3f72b427 LP |
600 | /* If the file handle for the directory we are |
601 | * interested in and its parent are identical, we | |
602 | * assume this is the root directory, which is a mount | |
603 | * point. */ | |
604 | ||
605 | if (h.handle.handle_bytes == h_parent.handle.handle_bytes && | |
606 | h.handle.handle_type == h_parent.handle.handle_type && | |
607 | memcmp(h.handle.f_handle, h_parent.handle.f_handle, h.handle.handle_bytes) == 0) | |
608 | return 1; | |
1640a0b6 | 609 | |
3f72b427 LP |
610 | return mount_id != mount_id_parent; |
611 | ||
612 | fallback_fdinfo: | |
5d409034 | 613 | r = fd_fdinfo_mnt_id(fd, filename, flags, &mount_id); |
3f72b427 LP |
614 | if (r == -EOPNOTSUPP) |
615 | goto fallback_fstat; | |
e792e890 | 616 | if (r < 0) |
3f72b427 | 617 | return r; |
9eb977db | 618 | |
5d409034 | 619 | r = fd_fdinfo_mnt_id(fd, "", AT_EMPTY_PATH, &mount_id_parent); |
1640a0b6 | 620 | if (r < 0) |
3f72b427 LP |
621 | return r; |
622 | ||
623 | if (mount_id != mount_id_parent) | |
624 | return 1; | |
625 | ||
626 | /* Hmm, so, the mount ids are the same. This leaves one | |
627 | * special case though for the root file system. For that, | |
628 | * let's see if the parent directory has the same inode as we | |
629 | * are interested in. Hence, let's also do fstat() checks now, | |
630 | * too, but avoid the st_dev comparisons, since they aren't | |
631 | * that useful on unionfs mounts. */ | |
632 | check_st_dev = false; | |
633 | ||
634 | fallback_fstat: | |
5d409034 MP |
635 | /* yay for fstatat() taking a different set of flags than the other |
636 | * _at() above */ | |
637 | if (flags & AT_SYMLINK_FOLLOW) | |
638 | flags &= ~AT_SYMLINK_FOLLOW; | |
639 | else | |
640 | flags |= AT_SYMLINK_NOFOLLOW; | |
641 | if (fstatat(fd, filename, &a, flags) < 0) | |
3f72b427 LP |
642 | return -errno; |
643 | ||
5d409034 | 644 | if (fstatat(fd, "", &b, AT_EMPTY_PATH) < 0) |
1640a0b6 LP |
645 | return -errno; |
646 | ||
05d990ef LP |
647 | /* A directory with same device and inode as its parent? Must |
648 | * be the root directory */ | |
649 | if (a.st_dev == b.st_dev && | |
650 | a.st_ino == b.st_ino) | |
651 | return 1; | |
652 | ||
3f72b427 | 653 | return check_st_dev && (a.st_dev != b.st_dev); |
9eb977db KS |
654 | } |
655 | ||
e26d6ce5 MP |
656 | /* flags can be AT_SYMLINK_FOLLOW or 0 */ |
657 | int path_is_mount_point(const char *t, int flags) { | |
f25afeb6 | 658 | _cleanup_close_ int fd = -1; |
36908eb8 | 659 | _cleanup_free_ char *canonical = NULL, *parent = NULL; |
5d409034 | 660 | int r; |
e792e890 | 661 | |
f25afeb6 LP |
662 | assert(t); |
663 | ||
664 | if (path_equal(t, "/")) | |
665 | return 1; | |
666 | ||
36908eb8 MP |
667 | /* we need to resolve symlinks manually, we can't just rely on |
668 | * fd_is_mount_point() to do that for us; if we have a structure like | |
669 | * /bin -> /usr/bin/ and /usr is a mount point, then the parent that we | |
670 | * look at needs to be /usr, not /. */ | |
671 | if (flags & AT_SYMLINK_FOLLOW) { | |
672 | canonical = canonicalize_file_name(t); | |
673 | if (!canonical) | |
674 | return -errno; | |
10c03e9e LP |
675 | |
676 | t = canonical; | |
36908eb8 MP |
677 | } |
678 | ||
10c03e9e | 679 | r = path_get_parent(t, &parent); |
5d409034 MP |
680 | if (r < 0) |
681 | return r; | |
682 | ||
683 | fd = openat(AT_FDCWD, parent, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|O_PATH); | |
e792e890 | 684 | if (fd < 0) |
f25afeb6 | 685 | return -errno; |
f25afeb6 | 686 | |
10c03e9e | 687 | return fd_is_mount_point(fd, basename(t), flags); |
f25afeb6 LP |
688 | } |
689 | ||
9eb977db KS |
690 | int path_is_read_only_fs(const char *path) { |
691 | struct statvfs st; | |
692 | ||
693 | assert(path); | |
694 | ||
695 | if (statvfs(path, &st) < 0) | |
696 | return -errno; | |
697 | ||
70421bdc LP |
698 | if (st.f_flag & ST_RDONLY) |
699 | return true; | |
700 | ||
701 | /* On NFS, statvfs() might not reflect whether we can actually | |
702 | * write to the remote share. Let's try again with | |
703 | * access(W_OK) which is more reliable, at least sometimes. */ | |
704 | if (access(path, W_OK) < 0 && errno == EROFS) | |
705 | return true; | |
706 | ||
707 | return false; | |
9eb977db | 708 | } |
66060897 LP |
709 | |
710 | int path_is_os_tree(const char *path) { | |
711 | char *p; | |
712 | int r; | |
713 | ||
5ae4d543 | 714 | /* We use /usr/lib/os-release as flag file if something is an OS */ |
63c372cb | 715 | p = strjoina(path, "/usr/lib/os-release"); |
5ae4d543 | 716 | r = access(p, F_OK); |
5ae4d543 LP |
717 | if (r >= 0) |
718 | return 1; | |
66060897 | 719 | |
5ae4d543 | 720 | /* Also check for the old location in /etc, just in case. */ |
63c372cb | 721 | p = strjoina(path, "/etc/os-release"); |
66060897 LP |
722 | r = access(p, F_OK); |
723 | ||
5ae4d543 | 724 | return r >= 0; |
66060897 | 725 | } |
c9d954b2 | 726 | |
85eca92e LP |
727 | int find_binary(const char *name, char **ret) { |
728 | int last_error, r; | |
729 | const char *p; | |
730 | ||
c9d954b2 | 731 | assert(name); |
4087cb9e | 732 | |
571d0134 | 733 | if (is_path(name)) { |
85eca92e | 734 | if (access(name, X_OK) < 0) |
b972115c ZJS |
735 | return -errno; |
736 | ||
85eca92e | 737 | if (ret) { |
0f474365 LP |
738 | r = path_make_absolute_cwd(name, ret); |
739 | if (r < 0) | |
740 | return r; | |
eb66db55 | 741 | } |
c9d954b2 | 742 | |
c9d954b2 | 743 | return 0; |
85eca92e | 744 | } |
c9d954b2 | 745 | |
85eca92e LP |
746 | /** |
747 | * Plain getenv, not secure_getenv, because we want | |
748 | * to actually allow the user to pick the binary. | |
749 | */ | |
750 | p = getenv("PATH"); | |
751 | if (!p) | |
752 | p = DEFAULT_PATH; | |
753 | ||
754 | last_error = -ENOENT; | |
755 | ||
756 | for (;;) { | |
757 | _cleanup_free_ char *j = NULL, *element = NULL; | |
758 | ||
759 | r = extract_first_word(&p, &element, ":", EXTRACT_RELAX|EXTRACT_DONT_COALESCE_SEPARATORS); | |
760 | if (r < 0) | |
761 | return r; | |
762 | if (r == 0) | |
763 | break; | |
764 | ||
0f474365 LP |
765 | if (!path_is_absolute(element)) |
766 | continue; | |
767 | ||
85eca92e LP |
768 | j = strjoin(element, "/", name, NULL); |
769 | if (!j) | |
770 | return -ENOMEM; | |
771 | ||
772 | if (access(j, X_OK) >= 0) { | |
773 | /* Found it! */ | |
c9d954b2 | 774 | |
85eca92e LP |
775 | if (ret) { |
776 | *ret = path_kill_slashes(j); | |
777 | j = NULL; | |
eb66db55 | 778 | } |
c9d954b2 ZJS |
779 | |
780 | return 0; | |
781 | } | |
782 | ||
85eca92e | 783 | last_error = -errno; |
c9d954b2 | 784 | } |
85eca92e LP |
785 | |
786 | return last_error; | |
c9d954b2 | 787 | } |
8e184852 | 788 | |
2ad8416d | 789 | bool paths_check_timestamp(const char* const* paths, usec_t *timestamp, bool update) { |
8e184852 | 790 | bool changed = false; |
2ad8416d | 791 | const char* const* i; |
8e184852 | 792 | |
97f2d76d TG |
793 | assert(timestamp); |
794 | ||
8e184852 | 795 | if (paths == NULL) |
4087cb9e | 796 | return false; |
8e184852 | 797 | |
4087cb9e | 798 | STRV_FOREACH(i, paths) { |
8e184852 | 799 | struct stat stats; |
4087cb9e | 800 | usec_t u; |
8e184852 | 801 | |
4087cb9e | 802 | if (stat(*i, &stats) < 0) |
8e184852 TG |
803 | continue; |
804 | ||
4087cb9e LP |
805 | u = timespec_load(&stats.st_mtim); |
806 | ||
97f2d76d | 807 | /* first check */ |
4087cb9e | 808 | if (*timestamp >= u) |
8e184852 TG |
809 | continue; |
810 | ||
9f6445e3 | 811 | log_debug("timestamp of '%s' changed", *i); |
8e184852 TG |
812 | |
813 | /* update timestamp */ | |
4087cb9e LP |
814 | if (update) { |
815 | *timestamp = u; | |
816 | changed = true; | |
817 | } else | |
818 | return true; | |
8e184852 | 819 | } |
4087cb9e | 820 | |
8e184852 TG |
821 | return changed; |
822 | } | |
eb66db55 | 823 | |
5bcd08db | 824 | static int binary_is_good(const char *binary) { |
571d0134 | 825 | _cleanup_free_ char *p = NULL, *d = NULL; |
571d0134 | 826 | int r; |
eb66db55 | 827 | |
85eca92e LP |
828 | r = find_binary(binary, &p); |
829 | if (r == -ENOENT) | |
830 | return 0; | |
571d0134 LP |
831 | if (r < 0) |
832 | return r; | |
833 | ||
061df014 | 834 | /* An fsck that is linked to /bin/true is a non-existent |
571d0134 LP |
835 | * fsck */ |
836 | ||
837 | r = readlink_malloc(p, &d); | |
85eca92e LP |
838 | if (r == -EINVAL) /* not a symlink */ |
839 | return 1; | |
840 | if (r < 0) | |
841 | return r; | |
571d0134 | 842 | |
85eca92e LP |
843 | return !path_equal(d, "true") && |
844 | !path_equal(d, "/bin/true") && | |
845 | !path_equal(d, "/usr/bin/true") && | |
846 | !path_equal(d, "/dev/null"); | |
eb66db55 | 847 | } |
1d13f648 | 848 | |
5bcd08db LP |
849 | int fsck_exists(const char *fstype) { |
850 | const char *checker; | |
851 | ||
85eca92e | 852 | assert(fstype); |
5bcd08db | 853 | |
85eca92e LP |
854 | if (streq(fstype, "auto")) |
855 | return -EINVAL; | |
856 | ||
857 | checker = strjoina("fsck.", fstype); | |
5bcd08db LP |
858 | return binary_is_good(checker); |
859 | } | |
860 | ||
861 | int mkfs_exists(const char *fstype) { | |
862 | const char *mkfs; | |
863 | ||
85eca92e | 864 | assert(fstype); |
5bcd08db | 865 | |
85eca92e LP |
866 | if (streq(fstype, "auto")) |
867 | return -EINVAL; | |
868 | ||
869 | mkfs = strjoina("mkfs.", fstype); | |
5bcd08db LP |
870 | return binary_is_good(mkfs); |
871 | } | |
872 | ||
1d13f648 LP |
873 | char *prefix_root(const char *root, const char *path) { |
874 | char *n, *p; | |
875 | size_t l; | |
876 | ||
877 | /* If root is passed, prefixes path with it. Otherwise returns | |
878 | * it as is. */ | |
879 | ||
880 | assert(path); | |
881 | ||
882 | /* First, drop duplicate prefixing slashes from the path */ | |
883 | while (path[0] == '/' && path[1] == '/') | |
884 | path++; | |
885 | ||
886 | if (isempty(root) || path_equal(root, "/")) | |
887 | return strdup(path); | |
888 | ||
889 | l = strlen(root) + 1 + strlen(path) + 1; | |
890 | ||
891 | n = new(char, l); | |
892 | if (!n) | |
893 | return NULL; | |
894 | ||
895 | p = stpcpy(n, root); | |
896 | ||
897 | while (p > n && p[-1] == '/') | |
898 | p--; | |
899 | ||
900 | if (path[0] != '/') | |
901 | *(p++) = '/'; | |
902 | ||
903 | strcpy(p, path); | |
904 | return n; | |
905 | } | |
0f03c2a4 LP |
906 | |
907 | int parse_path_argument_and_warn(const char *path, bool suppress_root, char **arg) { | |
908 | char *p; | |
909 | int r; | |
910 | ||
911 | /* | |
912 | * This function is intended to be used in command line | |
913 | * parsers, to handle paths that are passed in. It makes the | |
914 | * path absolute, and reduces it to NULL if omitted or | |
915 | * root (the latter optionally). | |
916 | * | |
917 | * NOTE THAT THIS WILL FREE THE PREVIOUS ARGUMENT POINTER ON | |
918 | * SUCCESS! Hence, do not pass in uninitialized pointers. | |
919 | */ | |
920 | ||
921 | if (isempty(path)) { | |
922 | *arg = mfree(*arg); | |
923 | return 0; | |
924 | } | |
925 | ||
926 | r = path_make_absolute_cwd(path, &p); | |
927 | if (r < 0) | |
928 | return log_error_errno(r, "Failed to parse path \"%s\" and make it absolute: %m", path); | |
929 | ||
930 | path_kill_slashes(p); | |
931 | if (suppress_root && path_equal(p, "/")) | |
932 | p = mfree(p); | |
933 | ||
934 | free(*arg); | |
935 | *arg = p; | |
936 | return 0; | |
937 | } |