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Commit | Line | Data |
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53e1b683 | 1 | /* SPDX-License-Identifier: LGPL-2.1+ */ |
f4f15635 LP |
2 | /*** |
3 | This file is part of systemd. | |
4 | ||
5 | Copyright 2010 Lennart Poettering | |
f4f15635 LP |
6 | ***/ |
7 | ||
11c3a366 TA |
8 | #include <errno.h> |
9 | #include <stddef.h> | |
10 | #include <stdio.h> | |
11 | #include <stdlib.h> | |
12 | #include <string.h> | |
13 | #include <sys/stat.h> | |
655f2da0 | 14 | #include <linux/magic.h> |
11c3a366 TA |
15 | #include <time.h> |
16 | #include <unistd.h> | |
17 | ||
b5efdb8a | 18 | #include "alloc-util.h" |
f4f15635 LP |
19 | #include "dirent-util.h" |
20 | #include "fd-util.h" | |
21 | #include "fileio.h" | |
22 | #include "fs-util.h" | |
11c3a366 TA |
23 | #include "log.h" |
24 | #include "macro.h" | |
25 | #include "missing.h" | |
93cc7779 TA |
26 | #include "mkdir.h" |
27 | #include "parse-util.h" | |
28 | #include "path-util.h" | |
dccca82b | 29 | #include "process-util.h" |
34a8f081 | 30 | #include "stat-util.h" |
430fbf8e | 31 | #include "stdio-util.h" |
f4f15635 LP |
32 | #include "string-util.h" |
33 | #include "strv.h" | |
93cc7779 | 34 | #include "time-util.h" |
ee104e11 | 35 | #include "user-util.h" |
f4f15635 LP |
36 | #include "util.h" |
37 | ||
38 | int unlink_noerrno(const char *path) { | |
39 | PROTECT_ERRNO; | |
40 | int r; | |
41 | ||
42 | r = unlink(path); | |
43 | if (r < 0) | |
44 | return -errno; | |
45 | ||
46 | return 0; | |
47 | } | |
48 | ||
49 | int rmdir_parents(const char *path, const char *stop) { | |
50 | size_t l; | |
51 | int r = 0; | |
52 | ||
53 | assert(path); | |
54 | assert(stop); | |
55 | ||
56 | l = strlen(path); | |
57 | ||
58 | /* Skip trailing slashes */ | |
59 | while (l > 0 && path[l-1] == '/') | |
60 | l--; | |
61 | ||
62 | while (l > 0) { | |
63 | char *t; | |
64 | ||
65 | /* Skip last component */ | |
66 | while (l > 0 && path[l-1] != '/') | |
67 | l--; | |
68 | ||
69 | /* Skip trailing slashes */ | |
70 | while (l > 0 && path[l-1] == '/') | |
71 | l--; | |
72 | ||
73 | if (l <= 0) | |
74 | break; | |
75 | ||
76 | t = strndup(path, l); | |
77 | if (!t) | |
78 | return -ENOMEM; | |
79 | ||
80 | if (path_startswith(stop, t)) { | |
81 | free(t); | |
82 | return 0; | |
83 | } | |
84 | ||
85 | r = rmdir(t); | |
86 | free(t); | |
87 | ||
88 | if (r < 0) | |
89 | if (errno != ENOENT) | |
90 | return -errno; | |
91 | } | |
92 | ||
93 | return 0; | |
94 | } | |
95 | ||
f4f15635 LP |
96 | int rename_noreplace(int olddirfd, const char *oldpath, int newdirfd, const char *newpath) { |
97 | struct stat buf; | |
98 | int ret; | |
99 | ||
100 | ret = renameat2(olddirfd, oldpath, newdirfd, newpath, RENAME_NOREPLACE); | |
101 | if (ret >= 0) | |
102 | return 0; | |
103 | ||
104 | /* renameat2() exists since Linux 3.15, btrfs added support for it later. | |
105 | * If it is not implemented, fallback to another method. */ | |
106 | if (!IN_SET(errno, EINVAL, ENOSYS)) | |
107 | return -errno; | |
108 | ||
109 | /* The link()/unlink() fallback does not work on directories. But | |
110 | * renameat() without RENAME_NOREPLACE gives the same semantics on | |
111 | * directories, except when newpath is an *empty* directory. This is | |
112 | * good enough. */ | |
113 | ret = fstatat(olddirfd, oldpath, &buf, AT_SYMLINK_NOFOLLOW); | |
114 | if (ret >= 0 && S_ISDIR(buf.st_mode)) { | |
115 | ret = renameat(olddirfd, oldpath, newdirfd, newpath); | |
116 | return ret >= 0 ? 0 : -errno; | |
117 | } | |
118 | ||
119 | /* If it is not a directory, use the link()/unlink() fallback. */ | |
120 | ret = linkat(olddirfd, oldpath, newdirfd, newpath, 0); | |
121 | if (ret < 0) | |
122 | return -errno; | |
123 | ||
124 | ret = unlinkat(olddirfd, oldpath, 0); | |
125 | if (ret < 0) { | |
126 | /* backup errno before the following unlinkat() alters it */ | |
127 | ret = errno; | |
128 | (void) unlinkat(newdirfd, newpath, 0); | |
129 | errno = ret; | |
130 | return -errno; | |
131 | } | |
132 | ||
133 | return 0; | |
134 | } | |
135 | ||
136 | int readlinkat_malloc(int fd, const char *p, char **ret) { | |
137 | size_t l = 100; | |
138 | int r; | |
139 | ||
140 | assert(p); | |
141 | assert(ret); | |
142 | ||
143 | for (;;) { | |
144 | char *c; | |
145 | ssize_t n; | |
146 | ||
147 | c = new(char, l); | |
148 | if (!c) | |
149 | return -ENOMEM; | |
150 | ||
151 | n = readlinkat(fd, p, c, l-1); | |
152 | if (n < 0) { | |
153 | r = -errno; | |
154 | free(c); | |
155 | return r; | |
156 | } | |
157 | ||
158 | if ((size_t) n < l-1) { | |
159 | c[n] = 0; | |
160 | *ret = c; | |
161 | return 0; | |
162 | } | |
163 | ||
164 | free(c); | |
165 | l *= 2; | |
166 | } | |
167 | } | |
168 | ||
169 | int readlink_malloc(const char *p, char **ret) { | |
170 | return readlinkat_malloc(AT_FDCWD, p, ret); | |
171 | } | |
172 | ||
173 | int readlink_value(const char *p, char **ret) { | |
174 | _cleanup_free_ char *link = NULL; | |
175 | char *value; | |
176 | int r; | |
177 | ||
178 | r = readlink_malloc(p, &link); | |
179 | if (r < 0) | |
180 | return r; | |
181 | ||
182 | value = basename(link); | |
183 | if (!value) | |
184 | return -ENOENT; | |
185 | ||
186 | value = strdup(value); | |
187 | if (!value) | |
188 | return -ENOMEM; | |
189 | ||
190 | *ret = value; | |
191 | ||
192 | return 0; | |
193 | } | |
194 | ||
195 | int readlink_and_make_absolute(const char *p, char **r) { | |
196 | _cleanup_free_ char *target = NULL; | |
197 | char *k; | |
198 | int j; | |
199 | ||
200 | assert(p); | |
201 | assert(r); | |
202 | ||
203 | j = readlink_malloc(p, &target); | |
204 | if (j < 0) | |
205 | return j; | |
206 | ||
207 | k = file_in_same_dir(p, target); | |
208 | if (!k) | |
209 | return -ENOMEM; | |
210 | ||
211 | *r = k; | |
212 | return 0; | |
213 | } | |
214 | ||
f4f15635 LP |
215 | int chmod_and_chown(const char *path, mode_t mode, uid_t uid, gid_t gid) { |
216 | assert(path); | |
217 | ||
218 | /* Under the assumption that we are running privileged we | |
219 | * first change the access mode and only then hand out | |
220 | * ownership to avoid a window where access is too open. */ | |
221 | ||
222 | if (mode != MODE_INVALID) | |
223 | if (chmod(path, mode) < 0) | |
224 | return -errno; | |
225 | ||
226 | if (uid != UID_INVALID || gid != GID_INVALID) | |
227 | if (chown(path, uid, gid) < 0) | |
228 | return -errno; | |
229 | ||
230 | return 0; | |
231 | } | |
232 | ||
f4f15635 LP |
233 | int fchmod_umask(int fd, mode_t m) { |
234 | mode_t u; | |
235 | int r; | |
236 | ||
237 | u = umask(0777); | |
238 | r = fchmod(fd, m & (~u)) < 0 ? -errno : 0; | |
239 | umask(u); | |
240 | ||
241 | return r; | |
242 | } | |
243 | ||
4dfaa528 FB |
244 | int fchmod_opath(int fd, mode_t m) { |
245 | char procfs_path[strlen("/proc/self/fd/") + DECIMAL_STR_MAX(int)]; | |
246 | ||
247 | /* This function operates also on fd that might have been opened with | |
248 | * O_PATH. Indeed fchmodat() doesn't have the AT_EMPTY_PATH flag like | |
249 | * fchownat() does. */ | |
250 | ||
251 | xsprintf(procfs_path, "/proc/self/fd/%i", fd); | |
252 | ||
253 | if (chmod(procfs_path, m) < 0) | |
254 | return -errno; | |
255 | ||
256 | return 0; | |
257 | } | |
258 | ||
f4f15635 LP |
259 | int fd_warn_permissions(const char *path, int fd) { |
260 | struct stat st; | |
261 | ||
262 | if (fstat(fd, &st) < 0) | |
263 | return -errno; | |
264 | ||
265 | if (st.st_mode & 0111) | |
266 | log_warning("Configuration file %s is marked executable. Please remove executable permission bits. Proceeding anyway.", path); | |
267 | ||
268 | if (st.st_mode & 0002) | |
269 | log_warning("Configuration file %s is marked world-writable. Please remove world writability permission bits. Proceeding anyway.", path); | |
270 | ||
df0ff127 | 271 | if (getpid_cached() == 1 && (st.st_mode & 0044) != 0044) |
f4f15635 LP |
272 | log_warning("Configuration file %s is marked world-inaccessible. This has no effect as configuration data is accessible via APIs without restrictions. Proceeding anyway.", path); |
273 | ||
274 | return 0; | |
275 | } | |
276 | ||
277 | int touch_file(const char *path, bool parents, usec_t stamp, uid_t uid, gid_t gid, mode_t mode) { | |
9e3fa6e8 LP |
278 | char fdpath[STRLEN("/proc/self/fd/") + DECIMAL_STR_MAX(int)]; |
279 | _cleanup_close_ int fd = -1; | |
280 | int r, ret = 0; | |
f4f15635 LP |
281 | |
282 | assert(path); | |
283 | ||
9e3fa6e8 LP |
284 | /* Note that touch_file() does not follow symlinks: if invoked on an existing symlink, then it is the symlink |
285 | * itself which is updated, not its target | |
286 | * | |
287 | * Returns the first error we encounter, but tries to apply as much as possible. */ | |
f4f15635 | 288 | |
9e3fa6e8 LP |
289 | if (parents) |
290 | (void) mkdir_parents(path, 0755); | |
291 | ||
292 | /* Initially, we try to open the node with O_PATH, so that we get a reference to the node. This is useful in | |
293 | * case the path refers to an existing device or socket node, as we can open it successfully in all cases, and | |
294 | * won't trigger any driver magic or so. */ | |
295 | fd = open(path, O_PATH|O_CLOEXEC|O_NOFOLLOW); | |
296 | if (fd < 0) { | |
297 | if (errno != ENOENT) | |
f4f15635 | 298 | return -errno; |
f4f15635 | 299 | |
9e3fa6e8 LP |
300 | /* if the node doesn't exist yet, we create it, but with O_EXCL, so that we only create a regular file |
301 | * here, and nothing else */ | |
302 | fd = open(path, O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC, IN_SET(mode, 0, MODE_INVALID) ? 0644 : mode); | |
303 | if (fd < 0) | |
f4f15635 LP |
304 | return -errno; |
305 | } | |
306 | ||
9e3fa6e8 LP |
307 | /* Let's make a path from the fd, and operate on that. With this logic, we can adjust the access mode, |
308 | * ownership and time of the file node in all cases, even if the fd refers to an O_PATH object — which is | |
309 | * something fchown(), fchmod(), futimensat() don't allow. */ | |
310 | xsprintf(fdpath, "/proc/self/fd/%i", fd); | |
311 | ||
312 | if (mode != MODE_INVALID) | |
313 | if (chmod(fdpath, mode) < 0) | |
314 | ret = -errno; | |
315 | ||
316 | if (uid_is_valid(uid) || gid_is_valid(gid)) | |
317 | if (chown(fdpath, uid, gid) < 0 && ret >= 0) | |
318 | ret = -errno; | |
319 | ||
f4f15635 LP |
320 | if (stamp != USEC_INFINITY) { |
321 | struct timespec ts[2]; | |
322 | ||
323 | timespec_store(&ts[0], stamp); | |
324 | ts[1] = ts[0]; | |
9e3fa6e8 | 325 | r = utimensat(AT_FDCWD, fdpath, ts, 0); |
f4f15635 | 326 | } else |
9e3fa6e8 LP |
327 | r = utimensat(AT_FDCWD, fdpath, NULL, 0); |
328 | if (r < 0 && ret >= 0) | |
f4f15635 LP |
329 | return -errno; |
330 | ||
9e3fa6e8 | 331 | return ret; |
f4f15635 LP |
332 | } |
333 | ||
334 | int touch(const char *path) { | |
ee735086 | 335 | return touch_file(path, false, USEC_INFINITY, UID_INVALID, GID_INVALID, MODE_INVALID); |
f4f15635 LP |
336 | } |
337 | ||
338 | int symlink_idempotent(const char *from, const char *to) { | |
f4f15635 LP |
339 | int r; |
340 | ||
341 | assert(from); | |
342 | assert(to); | |
343 | ||
344 | if (symlink(from, to) < 0) { | |
77b79723 LP |
345 | _cleanup_free_ char *p = NULL; |
346 | ||
f4f15635 LP |
347 | if (errno != EEXIST) |
348 | return -errno; | |
349 | ||
350 | r = readlink_malloc(to, &p); | |
77b79723 LP |
351 | if (r == -EINVAL) /* Not a symlink? In that case return the original error we encountered: -EEXIST */ |
352 | return -EEXIST; | |
353 | if (r < 0) /* Any other error? In that case propagate it as is */ | |
f4f15635 LP |
354 | return r; |
355 | ||
77b79723 LP |
356 | if (!streq(p, from)) /* Not the symlink we want it to be? In that case, propagate the original -EEXIST */ |
357 | return -EEXIST; | |
f4f15635 LP |
358 | } |
359 | ||
360 | return 0; | |
361 | } | |
362 | ||
363 | int symlink_atomic(const char *from, const char *to) { | |
364 | _cleanup_free_ char *t = NULL; | |
365 | int r; | |
366 | ||
367 | assert(from); | |
368 | assert(to); | |
369 | ||
370 | r = tempfn_random(to, NULL, &t); | |
371 | if (r < 0) | |
372 | return r; | |
373 | ||
374 | if (symlink(from, t) < 0) | |
375 | return -errno; | |
376 | ||
377 | if (rename(t, to) < 0) { | |
378 | unlink_noerrno(t); | |
379 | return -errno; | |
380 | } | |
381 | ||
382 | return 0; | |
383 | } | |
384 | ||
385 | int mknod_atomic(const char *path, mode_t mode, dev_t dev) { | |
386 | _cleanup_free_ char *t = NULL; | |
387 | int r; | |
388 | ||
389 | assert(path); | |
390 | ||
391 | r = tempfn_random(path, NULL, &t); | |
392 | if (r < 0) | |
393 | return r; | |
394 | ||
395 | if (mknod(t, mode, dev) < 0) | |
396 | return -errno; | |
397 | ||
398 | if (rename(t, path) < 0) { | |
399 | unlink_noerrno(t); | |
400 | return -errno; | |
401 | } | |
402 | ||
403 | return 0; | |
404 | } | |
405 | ||
406 | int mkfifo_atomic(const char *path, mode_t mode) { | |
407 | _cleanup_free_ char *t = NULL; | |
408 | int r; | |
409 | ||
410 | assert(path); | |
411 | ||
412 | r = tempfn_random(path, NULL, &t); | |
413 | if (r < 0) | |
414 | return r; | |
415 | ||
416 | if (mkfifo(t, mode) < 0) | |
417 | return -errno; | |
418 | ||
419 | if (rename(t, path) < 0) { | |
420 | unlink_noerrno(t); | |
421 | return -errno; | |
422 | } | |
423 | ||
424 | return 0; | |
425 | } | |
426 | ||
427 | int get_files_in_directory(const char *path, char ***list) { | |
428 | _cleanup_closedir_ DIR *d = NULL; | |
8fb3f009 | 429 | struct dirent *de; |
f4f15635 LP |
430 | size_t bufsize = 0, n = 0; |
431 | _cleanup_strv_free_ char **l = NULL; | |
432 | ||
433 | assert(path); | |
434 | ||
435 | /* Returns all files in a directory in *list, and the number | |
436 | * of files as return value. If list is NULL returns only the | |
437 | * number. */ | |
438 | ||
439 | d = opendir(path); | |
440 | if (!d) | |
441 | return -errno; | |
442 | ||
8fb3f009 | 443 | FOREACH_DIRENT_ALL(de, d, return -errno) { |
f4f15635 LP |
444 | dirent_ensure_type(d, de); |
445 | ||
446 | if (!dirent_is_file(de)) | |
447 | continue; | |
448 | ||
449 | if (list) { | |
450 | /* one extra slot is needed for the terminating NULL */ | |
451 | if (!GREEDY_REALLOC(l, bufsize, n + 2)) | |
452 | return -ENOMEM; | |
453 | ||
454 | l[n] = strdup(de->d_name); | |
455 | if (!l[n]) | |
456 | return -ENOMEM; | |
457 | ||
458 | l[++n] = NULL; | |
459 | } else | |
460 | n++; | |
461 | } | |
462 | ||
ae2a15bc LP |
463 | if (list) |
464 | *list = TAKE_PTR(l); | |
f4f15635 LP |
465 | |
466 | return n; | |
467 | } | |
430fbf8e | 468 | |
992e8f22 LP |
469 | static int getenv_tmp_dir(const char **ret_path) { |
470 | const char *n; | |
471 | int r, ret = 0; | |
34a8f081 | 472 | |
992e8f22 | 473 | assert(ret_path); |
34a8f081 | 474 | |
992e8f22 LP |
475 | /* We use the same order of environment variables python uses in tempfile.gettempdir(): |
476 | * https://docs.python.org/3/library/tempfile.html#tempfile.gettempdir */ | |
477 | FOREACH_STRING(n, "TMPDIR", "TEMP", "TMP") { | |
478 | const char *e; | |
479 | ||
480 | e = secure_getenv(n); | |
481 | if (!e) | |
482 | continue; | |
483 | if (!path_is_absolute(e)) { | |
484 | r = -ENOTDIR; | |
485 | goto next; | |
486 | } | |
99be45a4 | 487 | if (!path_is_normalized(e)) { |
992e8f22 LP |
488 | r = -EPERM; |
489 | goto next; | |
490 | } | |
491 | ||
492 | r = is_dir(e, true); | |
493 | if (r < 0) | |
494 | goto next; | |
495 | if (r == 0) { | |
496 | r = -ENOTDIR; | |
497 | goto next; | |
498 | } | |
499 | ||
500 | *ret_path = e; | |
501 | return 1; | |
502 | ||
503 | next: | |
504 | /* Remember first error, to make this more debuggable */ | |
505 | if (ret >= 0) | |
506 | ret = r; | |
34a8f081 OW |
507 | } |
508 | ||
992e8f22 LP |
509 | if (ret < 0) |
510 | return ret; | |
34a8f081 | 511 | |
992e8f22 LP |
512 | *ret_path = NULL; |
513 | return ret; | |
514 | } | |
34a8f081 | 515 | |
992e8f22 LP |
516 | static int tmp_dir_internal(const char *def, const char **ret) { |
517 | const char *e; | |
518 | int r, k; | |
519 | ||
520 | assert(def); | |
521 | assert(ret); | |
522 | ||
523 | r = getenv_tmp_dir(&e); | |
524 | if (r > 0) { | |
525 | *ret = e; | |
526 | return 0; | |
527 | } | |
528 | ||
529 | k = is_dir(def, true); | |
530 | if (k == 0) | |
531 | k = -ENOTDIR; | |
532 | if (k < 0) | |
533 | return r < 0 ? r : k; | |
534 | ||
535 | *ret = def; | |
34a8f081 OW |
536 | return 0; |
537 | } | |
538 | ||
992e8f22 LP |
539 | int var_tmp_dir(const char **ret) { |
540 | ||
541 | /* Returns the location for "larger" temporary files, that is backed by physical storage if available, and thus | |
542 | * even might survive a boot: /var/tmp. If $TMPDIR (or related environment variables) are set, its value is | |
543 | * returned preferably however. Note that both this function and tmp_dir() below are affected by $TMPDIR, | |
544 | * making it a variable that overrides all temporary file storage locations. */ | |
545 | ||
546 | return tmp_dir_internal("/var/tmp", ret); | |
547 | } | |
548 | ||
549 | int tmp_dir(const char **ret) { | |
550 | ||
551 | /* Similar to var_tmp_dir() above, but returns the location for "smaller" temporary files, which is usually | |
552 | * backed by an in-memory file system: /tmp. */ | |
553 | ||
554 | return tmp_dir_internal("/tmp", ret); | |
555 | } | |
556 | ||
af229d7a ZJS |
557 | int unlink_or_warn(const char *filename) { |
558 | if (unlink(filename) < 0 && errno != ENOENT) | |
559 | /* If the file doesn't exist and the fs simply was read-only (in which | |
560 | * case unlink() returns EROFS even if the file doesn't exist), don't | |
561 | * complain */ | |
562 | if (errno != EROFS || access(filename, F_OK) >= 0) | |
563 | return log_error_errno(errno, "Failed to remove \"%s\": %m", filename); | |
564 | ||
565 | return 0; | |
566 | } | |
567 | ||
430fbf8e | 568 | int inotify_add_watch_fd(int fd, int what, uint32_t mask) { |
fbd0b64f | 569 | char path[STRLEN("/proc/self/fd/") + DECIMAL_STR_MAX(int) + 1]; |
430fbf8e LP |
570 | int r; |
571 | ||
572 | /* This is like inotify_add_watch(), except that the file to watch is not referenced by a path, but by an fd */ | |
573 | xsprintf(path, "/proc/self/fd/%i", what); | |
574 | ||
575 | r = inotify_add_watch(fd, path, mask); | |
576 | if (r < 0) | |
577 | return -errno; | |
578 | ||
579 | return r; | |
580 | } | |
d944dc95 | 581 | |
f14f1806 LP |
582 | static bool safe_transition(const struct stat *a, const struct stat *b) { |
583 | /* Returns true if the transition from a to b is safe, i.e. that we never transition from unprivileged to | |
584 | * privileged files or directories. Why bother? So that unprivileged code can't symlink to privileged files | |
585 | * making us believe we read something safe even though it isn't safe in the specific context we open it in. */ | |
586 | ||
587 | if (a->st_uid == 0) /* Transitioning from privileged to unprivileged is always fine */ | |
588 | return true; | |
589 | ||
590 | return a->st_uid == b->st_uid; /* Otherwise we need to stay within the same UID */ | |
591 | } | |
592 | ||
c4f4fce7 | 593 | int chase_symlinks(const char *path, const char *original_root, unsigned flags, char **ret) { |
d944dc95 LP |
594 | _cleanup_free_ char *buffer = NULL, *done = NULL, *root = NULL; |
595 | _cleanup_close_ int fd = -1; | |
f10f4215 | 596 | unsigned max_follow = CHASE_SYMLINKS_MAX; /* how many symlinks to follow before giving up and returning ELOOP */ |
f14f1806 | 597 | struct stat previous_stat; |
a9fb0867 | 598 | bool exists = true; |
d944dc95 LP |
599 | char *todo; |
600 | int r; | |
601 | ||
602 | assert(path); | |
603 | ||
1ed34d75 LP |
604 | /* Either the file may be missing, or we return an fd to the final object, but both make no sense */ |
605 | if ((flags & (CHASE_NONEXISTENT|CHASE_OPEN)) == (CHASE_NONEXISTENT|CHASE_OPEN)) | |
606 | return -EINVAL; | |
607 | ||
49eb3659 LP |
608 | if ((flags & (CHASE_STEP|CHASE_OPEN)) == (CHASE_STEP|CHASE_OPEN)) |
609 | return -EINVAL; | |
610 | ||
a49424af LP |
611 | if (isempty(path)) |
612 | return -EINVAL; | |
613 | ||
d944dc95 LP |
614 | /* This is a lot like canonicalize_file_name(), but takes an additional "root" parameter, that allows following |
615 | * symlinks relative to a root directory, instead of the root of the host. | |
616 | * | |
fc4b68e5 | 617 | * Note that "root" primarily matters if we encounter an absolute symlink. It is also used when following |
c4f4fce7 LP |
618 | * relative symlinks to ensure they cannot be used to "escape" the root directory. The path parameter passed is |
619 | * assumed to be already prefixed by it, except if the CHASE_PREFIX_ROOT flag is set, in which case it is first | |
620 | * prefixed accordingly. | |
d944dc95 LP |
621 | * |
622 | * Algorithmically this operates on two path buffers: "done" are the components of the path we already | |
623 | * processed and resolved symlinks, "." and ".." of. "todo" are the components of the path we still need to | |
624 | * process. On each iteration, we move one component from "todo" to "done", processing it's special meaning | |
625 | * each time. The "todo" path always starts with at least one slash, the "done" path always ends in no | |
626 | * slash. We always keep an O_PATH fd to the component we are currently processing, thus keeping lookup races | |
fc4b68e5 LP |
627 | * at a minimum. |
628 | * | |
629 | * Suggested usage: whenever you want to canonicalize a path, use this function. Pass the absolute path you got | |
630 | * as-is: fully qualified and relative to your host's root. Optionally, specify the root parameter to tell this | |
631 | * function what to do when encountering a symlink with an absolute path as directory: prefix it by the | |
49eb3659 LP |
632 | * specified path. |
633 | * | |
634 | * There are three ways to invoke this function: | |
635 | * | |
636 | * 1. Without CHASE_STEP or CHASE_OPEN: in this case the path is resolved and the normalized path is returned | |
637 | * in `ret`. The return value is < 0 on error. If CHASE_NONEXISTENT is also set 0 is returned if the file | |
638 | * doesn't exist, > 0 otherwise. If CHASE_NONEXISTENT is not set >= 0 is returned if the destination was | |
639 | * found, -ENOENT if it doesn't. | |
640 | * | |
641 | * 2. With CHASE_OPEN: in this case the destination is opened after chasing it as O_PATH and this file | |
642 | * descriptor is returned as return value. This is useful to open files relative to some root | |
643 | * directory. Note that the returned O_PATH file descriptors must be converted into a regular one (using | |
644 | * fd_reopen() or such) before it can be used for reading/writing. CHASE_OPEN may not be combined with | |
645 | * CHASE_NONEXISTENT. | |
646 | * | |
647 | * 3. With CHASE_STEP: in this case only a single step of the normalization is executed, i.e. only the first | |
648 | * symlink or ".." component of the path is resolved, and the resulting path is returned. This is useful if | |
649 | * a caller wants to trace the a path through the file system verbosely. Returns < 0 on error, > 0 if the | |
650 | * path is fully normalized, and == 0 for each normalization step. This may be combined with | |
651 | * CHASE_NONEXISTENT, in which case 1 is returned when a component is not found. | |
652 | * | |
653 | * */ | |
d944dc95 | 654 | |
22bc57c5 | 655 | /* A root directory of "/" or "" is identical to none */ |
57ea45e1 | 656 | if (empty_or_root(original_root)) |
22bc57c5 | 657 | original_root = NULL; |
b1bfb848 | 658 | |
49eb3659 | 659 | if (!original_root && !ret && (flags & (CHASE_NONEXISTENT|CHASE_NO_AUTOFS|CHASE_SAFE|CHASE_OPEN|CHASE_STEP)) == CHASE_OPEN) { |
244d2f07 LP |
660 | /* Shortcut the CHASE_OPEN case if the caller isn't interested in the actual path and has no root set |
661 | * and doesn't care about any of the other special features we provide either. */ | |
662 | r = open(path, O_PATH|O_CLOEXEC); | |
663 | if (r < 0) | |
664 | return -errno; | |
665 | ||
666 | return r; | |
667 | } | |
668 | ||
c4f4fce7 LP |
669 | if (original_root) { |
670 | r = path_make_absolute_cwd(original_root, &root); | |
d944dc95 LP |
671 | if (r < 0) |
672 | return r; | |
c4f4fce7 | 673 | |
382a5078 LP |
674 | if (flags & CHASE_PREFIX_ROOT) { |
675 | ||
676 | /* We don't support relative paths in combination with a root directory */ | |
677 | if (!path_is_absolute(path)) | |
678 | return -EINVAL; | |
679 | ||
c4f4fce7 | 680 | path = prefix_roota(root, path); |
382a5078 | 681 | } |
d944dc95 LP |
682 | } |
683 | ||
c4f4fce7 LP |
684 | r = path_make_absolute_cwd(path, &buffer); |
685 | if (r < 0) | |
686 | return r; | |
687 | ||
d944dc95 LP |
688 | fd = open("/", O_CLOEXEC|O_NOFOLLOW|O_PATH); |
689 | if (fd < 0) | |
690 | return -errno; | |
691 | ||
f14f1806 LP |
692 | if (flags & CHASE_SAFE) { |
693 | if (fstat(fd, &previous_stat) < 0) | |
694 | return -errno; | |
695 | } | |
696 | ||
d944dc95 LP |
697 | todo = buffer; |
698 | for (;;) { | |
699 | _cleanup_free_ char *first = NULL; | |
700 | _cleanup_close_ int child = -1; | |
701 | struct stat st; | |
702 | size_t n, m; | |
703 | ||
704 | /* Determine length of first component in the path */ | |
705 | n = strspn(todo, "/"); /* The slashes */ | |
706 | m = n + strcspn(todo + n, "/"); /* The entire length of the component */ | |
707 | ||
708 | /* Extract the first component. */ | |
709 | first = strndup(todo, m); | |
710 | if (!first) | |
711 | return -ENOMEM; | |
712 | ||
713 | todo += m; | |
714 | ||
b12d25a8 ZJS |
715 | /* Empty? Then we reached the end. */ |
716 | if (isempty(first)) | |
717 | break; | |
718 | ||
d944dc95 | 719 | /* Just a single slash? Then we reached the end. */ |
b12d25a8 ZJS |
720 | if (path_equal(first, "/")) { |
721 | /* Preserve the trailing slash */ | |
62570f6f LP |
722 | |
723 | if (flags & CHASE_TRAIL_SLASH) | |
724 | if (!strextend(&done, "/", NULL)) | |
725 | return -ENOMEM; | |
b12d25a8 | 726 | |
d944dc95 | 727 | break; |
b12d25a8 | 728 | } |
d944dc95 LP |
729 | |
730 | /* Just a dot? Then let's eat this up. */ | |
731 | if (path_equal(first, "/.")) | |
732 | continue; | |
733 | ||
734 | /* Two dots? Then chop off the last bit of what we already found out. */ | |
735 | if (path_equal(first, "/..")) { | |
736 | _cleanup_free_ char *parent = NULL; | |
2b6d2dda | 737 | _cleanup_close_ int fd_parent = -1; |
d944dc95 | 738 | |
a4eaf3cf LP |
739 | /* If we already are at the top, then going up will not change anything. This is in-line with |
740 | * how the kernel handles this. */ | |
57ea45e1 | 741 | if (empty_or_root(done)) |
a4eaf3cf | 742 | continue; |
d944dc95 LP |
743 | |
744 | parent = dirname_malloc(done); | |
745 | if (!parent) | |
746 | return -ENOMEM; | |
747 | ||
a4eaf3cf | 748 | /* Don't allow this to leave the root dir. */ |
d944dc95 LP |
749 | if (root && |
750 | path_startswith(done, root) && | |
751 | !path_startswith(parent, root)) | |
a4eaf3cf | 752 | continue; |
d944dc95 | 753 | |
3b319885 | 754 | free_and_replace(done, parent); |
d944dc95 | 755 | |
49eb3659 LP |
756 | if (flags & CHASE_STEP) |
757 | goto chased_one; | |
758 | ||
d944dc95 LP |
759 | fd_parent = openat(fd, "..", O_CLOEXEC|O_NOFOLLOW|O_PATH); |
760 | if (fd_parent < 0) | |
761 | return -errno; | |
762 | ||
f14f1806 LP |
763 | if (flags & CHASE_SAFE) { |
764 | if (fstat(fd_parent, &st) < 0) | |
765 | return -errno; | |
766 | ||
767 | if (!safe_transition(&previous_stat, &st)) | |
768 | return -EPERM; | |
769 | ||
770 | previous_stat = st; | |
771 | } | |
772 | ||
d944dc95 | 773 | safe_close(fd); |
c10d6bdb | 774 | fd = TAKE_FD(fd_parent); |
d944dc95 LP |
775 | |
776 | continue; | |
777 | } | |
778 | ||
779 | /* Otherwise let's see what this is. */ | |
780 | child = openat(fd, first + n, O_CLOEXEC|O_NOFOLLOW|O_PATH); | |
a9fb0867 LP |
781 | if (child < 0) { |
782 | ||
783 | if (errno == ENOENT && | |
cb638b5e | 784 | (flags & CHASE_NONEXISTENT) && |
99be45a4 | 785 | (isempty(todo) || path_is_normalized(todo))) { |
a9fb0867 | 786 | |
cb638b5e | 787 | /* If CHASE_NONEXISTENT is set, and the path does not exist, then that's OK, return |
a9fb0867 LP |
788 | * what we got so far. But don't allow this if the remaining path contains "../ or "./" |
789 | * or something else weird. */ | |
790 | ||
a1904a46 YW |
791 | /* If done is "/", as first also contains slash at the head, then remove this redundant slash. */ |
792 | if (streq_ptr(done, "/")) | |
793 | *done = '\0'; | |
794 | ||
a9fb0867 LP |
795 | if (!strextend(&done, first, todo, NULL)) |
796 | return -ENOMEM; | |
797 | ||
798 | exists = false; | |
799 | break; | |
800 | } | |
801 | ||
d944dc95 | 802 | return -errno; |
a9fb0867 | 803 | } |
d944dc95 LP |
804 | |
805 | if (fstat(child, &st) < 0) | |
806 | return -errno; | |
f14f1806 LP |
807 | if ((flags & CHASE_SAFE) && |
808 | !safe_transition(&previous_stat, &st)) | |
809 | return -EPERM; | |
810 | ||
811 | previous_stat = st; | |
812 | ||
655f2da0 | 813 | if ((flags & CHASE_NO_AUTOFS) && |
a66fee2e | 814 | fd_is_fs_type(child, AUTOFS_SUPER_MAGIC) > 0) |
655f2da0 | 815 | return -EREMOTE; |
d944dc95 LP |
816 | |
817 | if (S_ISLNK(st.st_mode)) { | |
877777d7 CCW |
818 | char *joined; |
819 | ||
d944dc95 LP |
820 | _cleanup_free_ char *destination = NULL; |
821 | ||
822 | /* This is a symlink, in this case read the destination. But let's make sure we don't follow | |
823 | * symlinks without bounds. */ | |
824 | if (--max_follow <= 0) | |
825 | return -ELOOP; | |
826 | ||
827 | r = readlinkat_malloc(fd, first + n, &destination); | |
828 | if (r < 0) | |
829 | return r; | |
830 | if (isempty(destination)) | |
831 | return -EINVAL; | |
832 | ||
833 | if (path_is_absolute(destination)) { | |
834 | ||
835 | /* An absolute destination. Start the loop from the beginning, but use the root | |
836 | * directory as base. */ | |
837 | ||
838 | safe_close(fd); | |
839 | fd = open(root ?: "/", O_CLOEXEC|O_NOFOLLOW|O_PATH); | |
840 | if (fd < 0) | |
841 | return -errno; | |
842 | ||
f14f1806 LP |
843 | if (flags & CHASE_SAFE) { |
844 | if (fstat(fd, &st) < 0) | |
845 | return -errno; | |
846 | ||
847 | if (!safe_transition(&previous_stat, &st)) | |
848 | return -EPERM; | |
849 | ||
850 | previous_stat = st; | |
851 | } | |
852 | ||
b539437a YW |
853 | free(done); |
854 | ||
d944dc95 LP |
855 | /* Note that we do not revalidate the root, we take it as is. */ |
856 | if (isempty(root)) | |
857 | done = NULL; | |
858 | else { | |
859 | done = strdup(root); | |
860 | if (!done) | |
861 | return -ENOMEM; | |
862 | } | |
863 | ||
8c4a8ea2 LP |
864 | /* Prefix what's left to do with what we just read, and start the loop again, but |
865 | * remain in the current directory. */ | |
866 | joined = strjoin(destination, todo); | |
867 | } else | |
868 | joined = strjoin("/", destination, todo); | |
877777d7 CCW |
869 | if (!joined) |
870 | return -ENOMEM; | |
d944dc95 | 871 | |
877777d7 CCW |
872 | free(buffer); |
873 | todo = buffer = joined; | |
d944dc95 | 874 | |
49eb3659 LP |
875 | if (flags & CHASE_STEP) |
876 | goto chased_one; | |
877 | ||
d944dc95 LP |
878 | continue; |
879 | } | |
880 | ||
881 | /* If this is not a symlink, then let's just add the name we read to what we already verified. */ | |
ae2a15bc LP |
882 | if (!done) |
883 | done = TAKE_PTR(first); | |
884 | else { | |
a1904a46 YW |
885 | /* If done is "/", as first also contains slash at the head, then remove this redundant slash. */ |
886 | if (streq(done, "/")) | |
887 | *done = '\0'; | |
888 | ||
d944dc95 LP |
889 | if (!strextend(&done, first, NULL)) |
890 | return -ENOMEM; | |
891 | } | |
892 | ||
893 | /* And iterate again, but go one directory further down. */ | |
894 | safe_close(fd); | |
c10d6bdb | 895 | fd = TAKE_FD(child); |
d944dc95 LP |
896 | } |
897 | ||
898 | if (!done) { | |
899 | /* Special case, turn the empty string into "/", to indicate the root directory. */ | |
900 | done = strdup("/"); | |
901 | if (!done) | |
902 | return -ENOMEM; | |
903 | } | |
904 | ||
ae2a15bc LP |
905 | if (ret) |
906 | *ret = TAKE_PTR(done); | |
d944dc95 | 907 | |
1ed34d75 | 908 | if (flags & CHASE_OPEN) { |
1ed34d75 LP |
909 | /* Return the O_PATH fd we currently are looking to the caller. It can translate it to a proper fd by |
910 | * opening /proc/self/fd/xyz. */ | |
911 | ||
912 | assert(fd >= 0); | |
c10d6bdb | 913 | return TAKE_FD(fd); |
1ed34d75 LP |
914 | } |
915 | ||
49eb3659 LP |
916 | if (flags & CHASE_STEP) |
917 | return 1; | |
918 | ||
a9fb0867 | 919 | return exists; |
49eb3659 LP |
920 | |
921 | chased_one: | |
49eb3659 LP |
922 | if (ret) { |
923 | char *c; | |
924 | ||
027cc9c9 ZJS |
925 | c = strjoin(strempty(done), todo); |
926 | if (!c) | |
927 | return -ENOMEM; | |
49eb3659 LP |
928 | |
929 | *ret = c; | |
930 | } | |
931 | ||
932 | return 0; | |
d944dc95 | 933 | } |
57a4359e | 934 | |
21c692e9 LP |
935 | int chase_symlinks_and_open( |
936 | const char *path, | |
937 | const char *root, | |
938 | unsigned chase_flags, | |
939 | int open_flags, | |
940 | char **ret_path) { | |
941 | ||
942 | _cleanup_close_ int path_fd = -1; | |
943 | _cleanup_free_ char *p = NULL; | |
944 | int r; | |
945 | ||
946 | if (chase_flags & CHASE_NONEXISTENT) | |
947 | return -EINVAL; | |
948 | ||
57ea45e1 | 949 | if (empty_or_root(root) && !ret_path && (chase_flags & (CHASE_NO_AUTOFS|CHASE_SAFE)) == 0) { |
21c692e9 LP |
950 | /* Shortcut this call if none of the special features of this call are requested */ |
951 | r = open(path, open_flags); | |
952 | if (r < 0) | |
953 | return -errno; | |
954 | ||
955 | return r; | |
956 | } | |
957 | ||
958 | path_fd = chase_symlinks(path, root, chase_flags|CHASE_OPEN, ret_path ? &p : NULL); | |
959 | if (path_fd < 0) | |
960 | return path_fd; | |
961 | ||
962 | r = fd_reopen(path_fd, open_flags); | |
963 | if (r < 0) | |
964 | return r; | |
965 | ||
966 | if (ret_path) | |
967 | *ret_path = TAKE_PTR(p); | |
968 | ||
969 | return r; | |
970 | } | |
971 | ||
972 | int chase_symlinks_and_opendir( | |
973 | const char *path, | |
974 | const char *root, | |
975 | unsigned chase_flags, | |
976 | char **ret_path, | |
977 | DIR **ret_dir) { | |
978 | ||
979 | char procfs_path[STRLEN("/proc/self/fd/") + DECIMAL_STR_MAX(int)]; | |
980 | _cleanup_close_ int path_fd = -1; | |
981 | _cleanup_free_ char *p = NULL; | |
982 | DIR *d; | |
983 | ||
984 | if (!ret_dir) | |
985 | return -EINVAL; | |
986 | if (chase_flags & CHASE_NONEXISTENT) | |
987 | return -EINVAL; | |
988 | ||
57ea45e1 | 989 | if (empty_or_root(root) && !ret_path && (chase_flags & (CHASE_NO_AUTOFS|CHASE_SAFE)) == 0) { |
21c692e9 LP |
990 | /* Shortcut this call if none of the special features of this call are requested */ |
991 | d = opendir(path); | |
992 | if (!d) | |
993 | return -errno; | |
994 | ||
995 | *ret_dir = d; | |
996 | return 0; | |
997 | } | |
998 | ||
999 | path_fd = chase_symlinks(path, root, chase_flags|CHASE_OPEN, ret_path ? &p : NULL); | |
1000 | if (path_fd < 0) | |
1001 | return path_fd; | |
1002 | ||
1003 | xsprintf(procfs_path, "/proc/self/fd/%i", path_fd); | |
1004 | d = opendir(procfs_path); | |
1005 | if (!d) | |
1006 | return -errno; | |
1007 | ||
1008 | if (ret_path) | |
1009 | *ret_path = TAKE_PTR(p); | |
1010 | ||
1011 | *ret_dir = d; | |
1012 | return 0; | |
1013 | } | |
1014 | ||
d2bcd0ba LP |
1015 | int chase_symlinks_and_stat( |
1016 | const char *path, | |
1017 | const char *root, | |
1018 | unsigned chase_flags, | |
1019 | char **ret_path, | |
1020 | struct stat *ret_stat) { | |
1021 | ||
1022 | _cleanup_close_ int path_fd = -1; | |
1023 | _cleanup_free_ char *p = NULL; | |
1024 | ||
1025 | assert(path); | |
1026 | assert(ret_stat); | |
1027 | ||
1028 | if (chase_flags & CHASE_NONEXISTENT) | |
1029 | return -EINVAL; | |
1030 | ||
1031 | if (empty_or_root(root) && !ret_path && (chase_flags & (CHASE_NO_AUTOFS|CHASE_SAFE)) == 0) { | |
1032 | /* Shortcut this call if none of the special features of this call are requested */ | |
1033 | if (stat(path, ret_stat) < 0) | |
1034 | return -errno; | |
1035 | ||
1036 | return 1; | |
1037 | } | |
1038 | ||
1039 | path_fd = chase_symlinks(path, root, chase_flags|CHASE_OPEN, ret_path ? &p : NULL); | |
1040 | if (path_fd < 0) | |
1041 | return path_fd; | |
1042 | ||
1043 | if (fstat(path_fd, ret_stat) < 0) | |
1044 | return -errno; | |
1045 | ||
1046 | if (ret_path) | |
1047 | *ret_path = TAKE_PTR(p); | |
1048 | ||
1049 | if (chase_flags & CHASE_OPEN) | |
1050 | return TAKE_FD(path_fd); | |
1051 | ||
1052 | return 1; | |
1053 | } | |
1054 | ||
57a4359e | 1055 | int access_fd(int fd, int mode) { |
fbd0b64f | 1056 | char p[STRLEN("/proc/self/fd/") + DECIMAL_STR_MAX(fd) + 1]; |
57a4359e LP |
1057 | int r; |
1058 | ||
1059 | /* Like access() but operates on an already open fd */ | |
1060 | ||
1061 | xsprintf(p, "/proc/self/fd/%i", fd); | |
57a4359e LP |
1062 | r = access(p, mode); |
1063 | if (r < 0) | |
21c692e9 | 1064 | return -errno; |
57a4359e LP |
1065 | |
1066 | return r; | |
1067 | } | |
43767d9d LP |
1068 | |
1069 | int unlinkat_deallocate(int fd, const char *name, int flags) { | |
1070 | _cleanup_close_ int truncate_fd = -1; | |
1071 | struct stat st; | |
1072 | off_t l, bs; | |
1073 | ||
1074 | /* Operates like unlinkat() but also deallocates the file contents if it is a regular file and there's no other | |
1075 | * link to it. This is useful to ensure that other processes that might have the file open for reading won't be | |
1076 | * able to keep the data pinned on disk forever. This call is particular useful whenever we execute clean-up | |
1077 | * jobs ("vacuuming"), where we want to make sure the data is really gone and the disk space released and | |
1078 | * returned to the free pool. | |
1079 | * | |
1080 | * Deallocation is preferably done by FALLOC_FL_PUNCH_HOLE|FALLOC_FL_KEEP_SIZE (👊) if supported, which means | |
1081 | * the file won't change size. That's a good thing since we shouldn't needlessly trigger SIGBUS in other | |
1082 | * programs that have mmap()ed the file. (The assumption here is that changing file contents to all zeroes | |
1083 | * underneath those programs is the better choice than simply triggering SIGBUS in them which truncation does.) | |
1084 | * However if hole punching is not implemented in the kernel or file system we'll fall back to normal file | |
1085 | * truncation (🔪), as our goal of deallocating the data space trumps our goal of being nice to readers (💐). | |
1086 | * | |
1087 | * Note that we attempt deallocation, but failure to succeed with that is not considered fatal, as long as the | |
1088 | * primary job – to delete the file – is accomplished. */ | |
1089 | ||
1090 | if ((flags & AT_REMOVEDIR) == 0) { | |
1091 | truncate_fd = openat(fd, name, O_WRONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW|O_NONBLOCK); | |
1092 | if (truncate_fd < 0) { | |
1093 | ||
1094 | /* If this failed because the file doesn't exist propagate the error right-away. Also, | |
1095 | * AT_REMOVEDIR wasn't set, and we tried to open the file for writing, which means EISDIR is | |
1096 | * returned when this is a directory but we are not supposed to delete those, hence propagate | |
1097 | * the error right-away too. */ | |
1098 | if (IN_SET(errno, ENOENT, EISDIR)) | |
1099 | return -errno; | |
1100 | ||
1101 | if (errno != ELOOP) /* don't complain if this is a symlink */ | |
1102 | log_debug_errno(errno, "Failed to open file '%s' for deallocation, ignoring: %m", name); | |
1103 | } | |
1104 | } | |
1105 | ||
1106 | if (unlinkat(fd, name, flags) < 0) | |
1107 | return -errno; | |
1108 | ||
1109 | if (truncate_fd < 0) /* Don't have a file handle, can't do more ☹️ */ | |
1110 | return 0; | |
1111 | ||
1112 | if (fstat(truncate_fd, &st) < 0) { | |
1113 | log_debug_errno(errno, "Failed to stat file '%s' for deallocation, ignoring.", name); | |
1114 | return 0; | |
1115 | } | |
1116 | ||
1117 | if (!S_ISREG(st.st_mode) || st.st_blocks == 0 || st.st_nlink > 0) | |
1118 | return 0; | |
1119 | ||
1120 | /* If this is a regular file, it actually took up space on disk and there are no other links it's time to | |
1121 | * punch-hole/truncate this to release the disk space. */ | |
1122 | ||
1123 | bs = MAX(st.st_blksize, 512); | |
1124 | l = DIV_ROUND_UP(st.st_size, bs) * bs; /* Round up to next block size */ | |
1125 | ||
1126 | if (fallocate(truncate_fd, FALLOC_FL_PUNCH_HOLE|FALLOC_FL_KEEP_SIZE, 0, l) >= 0) | |
1127 | return 0; /* Successfully punched a hole! 😊 */ | |
1128 | ||
1129 | /* Fall back to truncation */ | |
1130 | if (ftruncate(truncate_fd, 0) < 0) { | |
1131 | log_debug_errno(errno, "Failed to truncate file to 0, ignoring: %m"); | |
1132 | return 0; | |
1133 | } | |
1134 | ||
1135 | return 0; | |
1136 | } | |
11b29a96 LP |
1137 | |
1138 | int fsync_directory_of_file(int fd) { | |
1139 | _cleanup_free_ char *path = NULL, *dn = NULL; | |
1140 | _cleanup_close_ int dfd = -1; | |
1141 | int r; | |
1142 | ||
1143 | r = fd_verify_regular(fd); | |
1144 | if (r < 0) | |
1145 | return r; | |
1146 | ||
1147 | r = fd_get_path(fd, &path); | |
3ceae1bc ZJS |
1148 | if (r < 0) { |
1149 | log_debug("Failed to query /proc/self/fd/%d%s: %m", | |
1150 | fd, | |
1151 | r == -EOPNOTSUPP ? ", ignoring" : ""); | |
1152 | ||
1153 | if (r == -EOPNOTSUPP) | |
1154 | /* If /proc is not available, we're most likely running in some | |
1155 | * chroot environment, and syncing the directory is not very | |
1156 | * important in that case. Let's just silently do nothing. */ | |
1157 | return 0; | |
1158 | ||
11b29a96 | 1159 | return r; |
3ceae1bc | 1160 | } |
11b29a96 LP |
1161 | |
1162 | if (!path_is_absolute(path)) | |
1163 | return -EINVAL; | |
1164 | ||
1165 | dn = dirname_malloc(path); | |
1166 | if (!dn) | |
1167 | return -ENOMEM; | |
1168 | ||
1169 | dfd = open(dn, O_RDONLY|O_CLOEXEC|O_DIRECTORY); | |
1170 | if (dfd < 0) | |
1171 | return -errno; | |
1172 | ||
1173 | if (fsync(dfd) < 0) | |
1174 | return -errno; | |
1175 | ||
1176 | return 0; | |
1177 | } |