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Commit | Line | Data |
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53e1b683 | 1 | /* SPDX-License-Identifier: LGPL-2.1+ */ |
f4f15635 | 2 | |
11c3a366 TA |
3 | #include <errno.h> |
4 | #include <stddef.h> | |
11c3a366 | 5 | #include <stdlib.h> |
1c73b069 | 6 | #include <linux/falloc.h> |
655f2da0 | 7 | #include <linux/magic.h> |
11c3a366 TA |
8 | #include <unistd.h> |
9 | ||
b5efdb8a | 10 | #include "alloc-util.h" |
ed9c0851 | 11 | #include "blockdev-util.h" |
f4f15635 LP |
12 | #include "dirent-util.h" |
13 | #include "fd-util.h" | |
ed9c0851 | 14 | #include "fileio.h" |
f4f15635 | 15 | #include "fs-util.h" |
fd74c6f3 | 16 | #include "locale-util.h" |
11c3a366 TA |
17 | #include "log.h" |
18 | #include "macro.h" | |
0499585f | 19 | #include "missing_fcntl.h" |
f5947a5e YW |
20 | #include "missing_fs.h" |
21 | #include "missing_syscall.h" | |
93cc7779 TA |
22 | #include "mkdir.h" |
23 | #include "parse-util.h" | |
24 | #include "path-util.h" | |
dccca82b | 25 | #include "process-util.h" |
34a8f081 | 26 | #include "stat-util.h" |
430fbf8e | 27 | #include "stdio-util.h" |
f4f15635 LP |
28 | #include "string-util.h" |
29 | #include "strv.h" | |
93cc7779 | 30 | #include "time-util.h" |
e4de7287 | 31 | #include "tmpfile-util.h" |
ee104e11 | 32 | #include "user-util.h" |
f4f15635 LP |
33 | #include "util.h" |
34 | ||
35 | int unlink_noerrno(const char *path) { | |
36 | PROTECT_ERRNO; | |
37 | int r; | |
38 | ||
39 | r = unlink(path); | |
40 | if (r < 0) | |
41 | return -errno; | |
42 | ||
43 | return 0; | |
44 | } | |
45 | ||
46 | int rmdir_parents(const char *path, const char *stop) { | |
47 | size_t l; | |
48 | int r = 0; | |
49 | ||
50 | assert(path); | |
51 | assert(stop); | |
52 | ||
53 | l = strlen(path); | |
54 | ||
55 | /* Skip trailing slashes */ | |
56 | while (l > 0 && path[l-1] == '/') | |
57 | l--; | |
58 | ||
59 | while (l > 0) { | |
60 | char *t; | |
61 | ||
62 | /* Skip last component */ | |
63 | while (l > 0 && path[l-1] != '/') | |
64 | l--; | |
65 | ||
66 | /* Skip trailing slashes */ | |
67 | while (l > 0 && path[l-1] == '/') | |
68 | l--; | |
69 | ||
70 | if (l <= 0) | |
71 | break; | |
72 | ||
73 | t = strndup(path, l); | |
74 | if (!t) | |
75 | return -ENOMEM; | |
76 | ||
77 | if (path_startswith(stop, t)) { | |
78 | free(t); | |
79 | return 0; | |
80 | } | |
81 | ||
82 | r = rmdir(t); | |
83 | free(t); | |
84 | ||
85 | if (r < 0) | |
86 | if (errno != ENOENT) | |
87 | return -errno; | |
88 | } | |
89 | ||
90 | return 0; | |
91 | } | |
92 | ||
f4f15635 | 93 | int rename_noreplace(int olddirfd, const char *oldpath, int newdirfd, const char *newpath) { |
2f15b625 | 94 | int r; |
f4f15635 | 95 | |
2f15b625 LP |
96 | /* Try the ideal approach first */ |
97 | if (renameat2(olddirfd, oldpath, newdirfd, newpath, RENAME_NOREPLACE) >= 0) | |
f4f15635 LP |
98 | return 0; |
99 | ||
2f15b625 LP |
100 | /* renameat2() exists since Linux 3.15, btrfs and FAT added support for it later. If it is not implemented, |
101 | * fall back to a different method. */ | |
102 | if (!IN_SET(errno, EINVAL, ENOSYS, ENOTTY)) | |
f4f15635 LP |
103 | return -errno; |
104 | ||
2f15b625 LP |
105 | /* Let's try to use linkat()+unlinkat() as fallback. This doesn't work on directories and on some file systems |
106 | * that do not support hard links (such as FAT, most prominently), but for files it's pretty close to what we | |
107 | * want — though not atomic (i.e. for a short period both the new and the old filename will exist). */ | |
108 | if (linkat(olddirfd, oldpath, newdirfd, newpath, 0) >= 0) { | |
109 | ||
110 | if (unlinkat(olddirfd, oldpath, 0) < 0) { | |
111 | r = -errno; /* Backup errno before the following unlinkat() alters it */ | |
112 | (void) unlinkat(newdirfd, newpath, 0); | |
113 | return r; | |
114 | } | |
115 | ||
116 | return 0; | |
f4f15635 LP |
117 | } |
118 | ||
2f15b625 | 119 | if (!IN_SET(errno, EINVAL, ENOSYS, ENOTTY, EPERM)) /* FAT returns EPERM on link()… */ |
f4f15635 LP |
120 | return -errno; |
121 | ||
2f15b625 LP |
122 | /* OK, neither RENAME_NOREPLACE nor linkat()+unlinkat() worked. Let's then fallback to the racy TOCTOU |
123 | * vulnerable accessat(F_OK) check followed by classic, replacing renameat(), we have nothing better. */ | |
124 | ||
125 | if (faccessat(newdirfd, newpath, F_OK, AT_SYMLINK_NOFOLLOW) >= 0) | |
126 | return -EEXIST; | |
127 | if (errno != ENOENT) | |
128 | return -errno; | |
129 | ||
130 | if (renameat(olddirfd, oldpath, newdirfd, newpath) < 0) | |
f4f15635 | 131 | return -errno; |
f4f15635 LP |
132 | |
133 | return 0; | |
134 | } | |
135 | ||
136 | int readlinkat_malloc(int fd, const char *p, char **ret) { | |
8e060ec2 | 137 | size_t l = FILENAME_MAX+1; |
f4f15635 LP |
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 | 215 | int chmod_and_chown(const char *path, mode_t mode, uid_t uid, gid_t gid) { |
de321f52 | 216 | _cleanup_close_ int fd = -1; |
30ff18d8 | 217 | |
f4f15635 LP |
218 | assert(path); |
219 | ||
30ff18d8 LP |
220 | fd = open(path, O_PATH|O_CLOEXEC|O_NOFOLLOW); /* Let's acquire an O_PATH fd, as precaution to change |
221 | * mode/owner on the same file */ | |
de321f52 LP |
222 | if (fd < 0) |
223 | return -errno; | |
224 | ||
2dbb7e94 | 225 | return fchmod_and_chown(fd, mode, uid, gid); |
b8da477e YW |
226 | } |
227 | ||
228 | int fchmod_and_chown(int fd, mode_t mode, uid_t uid, gid_t gid) { | |
2dbb7e94 | 229 | bool do_chown, do_chmod; |
30ff18d8 | 230 | struct stat st; |
30ff18d8 | 231 | |
2dbb7e94 LP |
232 | /* Change ownership and access mode of the specified fd. Tries to do so safely, ensuring that at no |
233 | * point in time the access mode is above the old access mode under the old ownership or the new | |
234 | * access mode under the new ownership. Note: this call tries hard to leave the access mode | |
235 | * unaffected if the uid/gid is changed, i.e. it undoes implicit suid/sgid dropping the kernel does | |
236 | * on chown(). | |
237 | * | |
71ec74d1 | 238 | * This call is happy with O_PATH fds. */ |
b8da477e | 239 | |
71ec74d1 | 240 | if (fstat(fd, &st) < 0) |
2dbb7e94 | 241 | return -errno; |
de321f52 | 242 | |
2dbb7e94 LP |
243 | do_chown = |
244 | (uid != UID_INVALID && st.st_uid != uid) || | |
245 | (gid != GID_INVALID && st.st_gid != gid); | |
de321f52 | 246 | |
2dbb7e94 LP |
247 | do_chmod = |
248 | !S_ISLNK(st.st_mode) && /* chmod is not defined on symlinks */ | |
249 | ((mode != MODE_INVALID && ((st.st_mode ^ mode) & 07777) != 0) || | |
250 | do_chown); /* If we change ownership, make sure we reset the mode afterwards, since chown() | |
251 | * modifies the access mode too */ | |
30ff18d8 | 252 | |
2dbb7e94 LP |
253 | if (mode == MODE_INVALID) |
254 | mode = st.st_mode; /* If we only shall do a chown(), save original mode, since chown() might break it. */ | |
255 | else if ((mode & S_IFMT) != 0 && ((mode ^ st.st_mode) & S_IFMT) != 0) | |
256 | return -EINVAL; /* insist on the right file type if it was specified */ | |
de321f52 | 257 | |
2dbb7e94 LP |
258 | if (do_chown && do_chmod) { |
259 | mode_t minimal = st.st_mode & mode; /* the subset of the old and the new mask */ | |
30ff18d8 | 260 | |
2dbb7e94 | 261 | if (((minimal ^ st.st_mode) & 07777) != 0) |
71ec74d1 | 262 | if (fchmod_opath(fd, minimal & 07777) < 0) |
30ff18d8 | 263 | return -errno; |
de321f52 | 264 | } |
b8da477e | 265 | |
2dbb7e94 | 266 | if (do_chown) |
71ec74d1 | 267 | if (fchownat(fd, "", uid, gid, AT_EMPTY_PATH) < 0) |
2dbb7e94 | 268 | return -errno; |
30ff18d8 | 269 | |
2dbb7e94 | 270 | if (do_chmod) |
71ec74d1 | 271 | if (fchmod_opath(fd, mode & 07777) < 0) |
2dbb7e94 | 272 | return -errno; |
30ff18d8 | 273 | |
2dbb7e94 | 274 | return do_chown || do_chmod; |
f4f15635 LP |
275 | } |
276 | ||
6cb356ca ZJS |
277 | int chmod_and_chown_unsafe(const char *path, mode_t mode, uid_t uid, gid_t gid) { |
278 | bool do_chown, do_chmod; | |
279 | struct stat st; | |
280 | ||
281 | assert(path); | |
282 | ||
283 | /* Change ownership and access mode of the specified path, see description of fchmod_and_chown(). | |
284 | * Should only be used on trusted paths. */ | |
285 | ||
286 | if (lstat(path, &st) < 0) | |
287 | return -errno; | |
288 | ||
289 | do_chown = | |
290 | (uid != UID_INVALID && st.st_uid != uid) || | |
291 | (gid != GID_INVALID && st.st_gid != gid); | |
292 | ||
293 | do_chmod = | |
294 | !S_ISLNK(st.st_mode) && /* chmod is not defined on symlinks */ | |
295 | ((mode != MODE_INVALID && ((st.st_mode ^ mode) & 07777) != 0) || | |
296 | do_chown); /* If we change ownership, make sure we reset the mode afterwards, since chown() | |
297 | * modifies the access mode too */ | |
298 | ||
299 | if (mode == MODE_INVALID) | |
300 | mode = st.st_mode; /* If we only shall do a chown(), save original mode, since chown() might break it. */ | |
301 | else if ((mode & S_IFMT) != 0 && ((mode ^ st.st_mode) & S_IFMT) != 0) | |
302 | return -EINVAL; /* insist on the right file type if it was specified */ | |
303 | ||
304 | if (do_chown && do_chmod) { | |
305 | mode_t minimal = st.st_mode & mode; /* the subset of the old and the new mask */ | |
306 | ||
307 | if (((minimal ^ st.st_mode) & 07777) != 0) | |
308 | if (chmod(path, minimal & 07777) < 0) | |
309 | return -errno; | |
310 | } | |
311 | ||
312 | if (do_chown) | |
313 | if (lchown(path, uid, gid) < 0) | |
314 | return -errno; | |
315 | ||
316 | if (do_chmod) | |
317 | if (chmod(path, mode & 07777) < 0) | |
318 | return -errno; | |
319 | ||
320 | return do_chown || do_chmod; | |
321 | } | |
322 | ||
f4f15635 LP |
323 | int fchmod_umask(int fd, mode_t m) { |
324 | mode_t u; | |
325 | int r; | |
326 | ||
327 | u = umask(0777); | |
328 | r = fchmod(fd, m & (~u)) < 0 ? -errno : 0; | |
329 | umask(u); | |
330 | ||
331 | return r; | |
332 | } | |
333 | ||
4dfaa528 | 334 | int fchmod_opath(int fd, mode_t m) { |
22dd8d35 | 335 | char procfs_path[STRLEN("/proc/self/fd/") + DECIMAL_STR_MAX(int)]; |
4dfaa528 FB |
336 | |
337 | /* This function operates also on fd that might have been opened with | |
338 | * O_PATH. Indeed fchmodat() doesn't have the AT_EMPTY_PATH flag like | |
339 | * fchownat() does. */ | |
340 | ||
341 | xsprintf(procfs_path, "/proc/self/fd/%i", fd); | |
f8606626 LP |
342 | if (chmod(procfs_path, m) < 0) { |
343 | if (errno != ENOENT) | |
344 | return -errno; | |
345 | ||
346 | if (proc_mounted() == 0) | |
347 | return -ENOSYS; /* if we have no /proc/, the concept is not implementable */ | |
348 | ||
349 | return -ENOENT; | |
350 | } | |
4dfaa528 FB |
351 | |
352 | return 0; | |
353 | } | |
354 | ||
f4f15635 LP |
355 | int fd_warn_permissions(const char *path, int fd) { |
356 | struct stat st; | |
357 | ||
358 | if (fstat(fd, &st) < 0) | |
359 | return -errno; | |
360 | ||
b6cceaae LP |
361 | /* Don't complain if we are reading something that is not a file, for example /dev/null */ |
362 | if (!S_ISREG(st.st_mode)) | |
363 | return 0; | |
364 | ||
f4f15635 LP |
365 | if (st.st_mode & 0111) |
366 | log_warning("Configuration file %s is marked executable. Please remove executable permission bits. Proceeding anyway.", path); | |
367 | ||
368 | if (st.st_mode & 0002) | |
369 | log_warning("Configuration file %s is marked world-writable. Please remove world writability permission bits. Proceeding anyway.", path); | |
370 | ||
df0ff127 | 371 | if (getpid_cached() == 1 && (st.st_mode & 0044) != 0044) |
f4f15635 LP |
372 | 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); |
373 | ||
374 | return 0; | |
375 | } | |
376 | ||
377 | int touch_file(const char *path, bool parents, usec_t stamp, uid_t uid, gid_t gid, mode_t mode) { | |
9e3fa6e8 LP |
378 | char fdpath[STRLEN("/proc/self/fd/") + DECIMAL_STR_MAX(int)]; |
379 | _cleanup_close_ int fd = -1; | |
380 | int r, ret = 0; | |
f4f15635 LP |
381 | |
382 | assert(path); | |
383 | ||
9e3fa6e8 LP |
384 | /* Note that touch_file() does not follow symlinks: if invoked on an existing symlink, then it is the symlink |
385 | * itself which is updated, not its target | |
386 | * | |
387 | * Returns the first error we encounter, but tries to apply as much as possible. */ | |
f4f15635 | 388 | |
9e3fa6e8 LP |
389 | if (parents) |
390 | (void) mkdir_parents(path, 0755); | |
391 | ||
392 | /* Initially, we try to open the node with O_PATH, so that we get a reference to the node. This is useful in | |
393 | * case the path refers to an existing device or socket node, as we can open it successfully in all cases, and | |
394 | * won't trigger any driver magic or so. */ | |
395 | fd = open(path, O_PATH|O_CLOEXEC|O_NOFOLLOW); | |
396 | if (fd < 0) { | |
397 | if (errno != ENOENT) | |
f4f15635 | 398 | return -errno; |
f4f15635 | 399 | |
9e3fa6e8 LP |
400 | /* if the node doesn't exist yet, we create it, but with O_EXCL, so that we only create a regular file |
401 | * here, and nothing else */ | |
402 | fd = open(path, O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC, IN_SET(mode, 0, MODE_INVALID) ? 0644 : mode); | |
403 | if (fd < 0) | |
f4f15635 LP |
404 | return -errno; |
405 | } | |
406 | ||
9e3fa6e8 LP |
407 | /* Let's make a path from the fd, and operate on that. With this logic, we can adjust the access mode, |
408 | * ownership and time of the file node in all cases, even if the fd refers to an O_PATH object — which is | |
409 | * something fchown(), fchmod(), futimensat() don't allow. */ | |
410 | xsprintf(fdpath, "/proc/self/fd/%i", fd); | |
411 | ||
4b3b5bc7 | 412 | ret = fchmod_and_chown(fd, mode, uid, gid); |
9e3fa6e8 | 413 | |
f4f15635 LP |
414 | if (stamp != USEC_INFINITY) { |
415 | struct timespec ts[2]; | |
416 | ||
417 | timespec_store(&ts[0], stamp); | |
418 | ts[1] = ts[0]; | |
9e3fa6e8 | 419 | r = utimensat(AT_FDCWD, fdpath, ts, 0); |
f4f15635 | 420 | } else |
9e3fa6e8 LP |
421 | r = utimensat(AT_FDCWD, fdpath, NULL, 0); |
422 | if (r < 0 && ret >= 0) | |
f4f15635 LP |
423 | return -errno; |
424 | ||
9e3fa6e8 | 425 | return ret; |
f4f15635 LP |
426 | } |
427 | ||
428 | int touch(const char *path) { | |
ee735086 | 429 | return touch_file(path, false, USEC_INFINITY, UID_INVALID, GID_INVALID, MODE_INVALID); |
f4f15635 LP |
430 | } |
431 | ||
6c9c51e5 YW |
432 | int symlink_idempotent(const char *from, const char *to, bool make_relative) { |
433 | _cleanup_free_ char *relpath = NULL; | |
f4f15635 LP |
434 | int r; |
435 | ||
436 | assert(from); | |
437 | assert(to); | |
438 | ||
6c9c51e5 YW |
439 | if (make_relative) { |
440 | _cleanup_free_ char *parent = NULL; | |
441 | ||
442 | parent = dirname_malloc(to); | |
443 | if (!parent) | |
444 | return -ENOMEM; | |
445 | ||
446 | r = path_make_relative(parent, from, &relpath); | |
447 | if (r < 0) | |
448 | return r; | |
449 | ||
450 | from = relpath; | |
451 | } | |
452 | ||
f4f15635 | 453 | if (symlink(from, to) < 0) { |
77b79723 LP |
454 | _cleanup_free_ char *p = NULL; |
455 | ||
f4f15635 LP |
456 | if (errno != EEXIST) |
457 | return -errno; | |
458 | ||
459 | r = readlink_malloc(to, &p); | |
77b79723 LP |
460 | if (r == -EINVAL) /* Not a symlink? In that case return the original error we encountered: -EEXIST */ |
461 | return -EEXIST; | |
462 | if (r < 0) /* Any other error? In that case propagate it as is */ | |
f4f15635 LP |
463 | return r; |
464 | ||
77b79723 LP |
465 | if (!streq(p, from)) /* Not the symlink we want it to be? In that case, propagate the original -EEXIST */ |
466 | return -EEXIST; | |
f4f15635 LP |
467 | } |
468 | ||
469 | return 0; | |
470 | } | |
471 | ||
472 | int symlink_atomic(const char *from, const char *to) { | |
473 | _cleanup_free_ char *t = NULL; | |
474 | int r; | |
475 | ||
476 | assert(from); | |
477 | assert(to); | |
478 | ||
479 | r = tempfn_random(to, NULL, &t); | |
480 | if (r < 0) | |
481 | return r; | |
482 | ||
483 | if (symlink(from, t) < 0) | |
484 | return -errno; | |
485 | ||
486 | if (rename(t, to) < 0) { | |
487 | unlink_noerrno(t); | |
488 | return -errno; | |
489 | } | |
490 | ||
491 | return 0; | |
492 | } | |
493 | ||
494 | int mknod_atomic(const char *path, mode_t mode, dev_t dev) { | |
495 | _cleanup_free_ char *t = NULL; | |
496 | int r; | |
497 | ||
498 | assert(path); | |
499 | ||
500 | r = tempfn_random(path, NULL, &t); | |
501 | if (r < 0) | |
502 | return r; | |
503 | ||
504 | if (mknod(t, mode, dev) < 0) | |
505 | return -errno; | |
506 | ||
507 | if (rename(t, path) < 0) { | |
508 | unlink_noerrno(t); | |
509 | return -errno; | |
510 | } | |
511 | ||
512 | return 0; | |
513 | } | |
514 | ||
515 | int mkfifo_atomic(const char *path, mode_t mode) { | |
516 | _cleanup_free_ char *t = NULL; | |
517 | int r; | |
518 | ||
519 | assert(path); | |
520 | ||
521 | r = tempfn_random(path, NULL, &t); | |
522 | if (r < 0) | |
523 | return r; | |
524 | ||
525 | if (mkfifo(t, mode) < 0) | |
526 | return -errno; | |
527 | ||
528 | if (rename(t, path) < 0) { | |
4fe3828c FB |
529 | unlink_noerrno(t); |
530 | return -errno; | |
531 | } | |
532 | ||
533 | return 0; | |
534 | } | |
535 | ||
536 | int mkfifoat_atomic(int dirfd, const char *path, mode_t mode) { | |
537 | _cleanup_free_ char *t = NULL; | |
538 | int r; | |
539 | ||
540 | assert(path); | |
541 | ||
542 | if (path_is_absolute(path)) | |
543 | return mkfifo_atomic(path, mode); | |
544 | ||
545 | /* We're only interested in the (random) filename. */ | |
546 | r = tempfn_random_child("", NULL, &t); | |
547 | if (r < 0) | |
548 | return r; | |
549 | ||
550 | if (mkfifoat(dirfd, t, mode) < 0) | |
551 | return -errno; | |
552 | ||
553 | if (renameat(dirfd, t, dirfd, path) < 0) { | |
f4f15635 LP |
554 | unlink_noerrno(t); |
555 | return -errno; | |
556 | } | |
557 | ||
558 | return 0; | |
559 | } | |
560 | ||
561 | int get_files_in_directory(const char *path, char ***list) { | |
562 | _cleanup_closedir_ DIR *d = NULL; | |
8fb3f009 | 563 | struct dirent *de; |
f4f15635 LP |
564 | size_t bufsize = 0, n = 0; |
565 | _cleanup_strv_free_ char **l = NULL; | |
566 | ||
567 | assert(path); | |
568 | ||
569 | /* Returns all files in a directory in *list, and the number | |
570 | * of files as return value. If list is NULL returns only the | |
571 | * number. */ | |
572 | ||
573 | d = opendir(path); | |
574 | if (!d) | |
575 | return -errno; | |
576 | ||
8fb3f009 | 577 | FOREACH_DIRENT_ALL(de, d, return -errno) { |
f4f15635 LP |
578 | dirent_ensure_type(d, de); |
579 | ||
580 | if (!dirent_is_file(de)) | |
581 | continue; | |
582 | ||
583 | if (list) { | |
584 | /* one extra slot is needed for the terminating NULL */ | |
585 | if (!GREEDY_REALLOC(l, bufsize, n + 2)) | |
586 | return -ENOMEM; | |
587 | ||
588 | l[n] = strdup(de->d_name); | |
589 | if (!l[n]) | |
590 | return -ENOMEM; | |
591 | ||
592 | l[++n] = NULL; | |
593 | } else | |
594 | n++; | |
595 | } | |
596 | ||
ae2a15bc LP |
597 | if (list) |
598 | *list = TAKE_PTR(l); | |
f4f15635 LP |
599 | |
600 | return n; | |
601 | } | |
430fbf8e | 602 | |
992e8f22 LP |
603 | static int getenv_tmp_dir(const char **ret_path) { |
604 | const char *n; | |
605 | int r, ret = 0; | |
34a8f081 | 606 | |
992e8f22 | 607 | assert(ret_path); |
34a8f081 | 608 | |
992e8f22 LP |
609 | /* We use the same order of environment variables python uses in tempfile.gettempdir(): |
610 | * https://docs.python.org/3/library/tempfile.html#tempfile.gettempdir */ | |
611 | FOREACH_STRING(n, "TMPDIR", "TEMP", "TMP") { | |
612 | const char *e; | |
613 | ||
614 | e = secure_getenv(n); | |
615 | if (!e) | |
616 | continue; | |
617 | if (!path_is_absolute(e)) { | |
618 | r = -ENOTDIR; | |
619 | goto next; | |
620 | } | |
99be45a4 | 621 | if (!path_is_normalized(e)) { |
992e8f22 LP |
622 | r = -EPERM; |
623 | goto next; | |
624 | } | |
625 | ||
626 | r = is_dir(e, true); | |
627 | if (r < 0) | |
628 | goto next; | |
629 | if (r == 0) { | |
630 | r = -ENOTDIR; | |
631 | goto next; | |
632 | } | |
633 | ||
634 | *ret_path = e; | |
635 | return 1; | |
636 | ||
637 | next: | |
638 | /* Remember first error, to make this more debuggable */ | |
639 | if (ret >= 0) | |
640 | ret = r; | |
34a8f081 OW |
641 | } |
642 | ||
992e8f22 LP |
643 | if (ret < 0) |
644 | return ret; | |
34a8f081 | 645 | |
992e8f22 LP |
646 | *ret_path = NULL; |
647 | return ret; | |
648 | } | |
34a8f081 | 649 | |
992e8f22 LP |
650 | static int tmp_dir_internal(const char *def, const char **ret) { |
651 | const char *e; | |
652 | int r, k; | |
653 | ||
654 | assert(def); | |
655 | assert(ret); | |
656 | ||
657 | r = getenv_tmp_dir(&e); | |
658 | if (r > 0) { | |
659 | *ret = e; | |
660 | return 0; | |
661 | } | |
662 | ||
663 | k = is_dir(def, true); | |
664 | if (k == 0) | |
665 | k = -ENOTDIR; | |
666 | if (k < 0) | |
667 | return r < 0 ? r : k; | |
668 | ||
669 | *ret = def; | |
34a8f081 OW |
670 | return 0; |
671 | } | |
672 | ||
992e8f22 LP |
673 | int var_tmp_dir(const char **ret) { |
674 | ||
675 | /* Returns the location for "larger" temporary files, that is backed by physical storage if available, and thus | |
676 | * even might survive a boot: /var/tmp. If $TMPDIR (or related environment variables) are set, its value is | |
677 | * returned preferably however. Note that both this function and tmp_dir() below are affected by $TMPDIR, | |
678 | * making it a variable that overrides all temporary file storage locations. */ | |
679 | ||
680 | return tmp_dir_internal("/var/tmp", ret); | |
681 | } | |
682 | ||
683 | int tmp_dir(const char **ret) { | |
684 | ||
685 | /* Similar to var_tmp_dir() above, but returns the location for "smaller" temporary files, which is usually | |
686 | * backed by an in-memory file system: /tmp. */ | |
687 | ||
688 | return tmp_dir_internal("/tmp", ret); | |
689 | } | |
690 | ||
af229d7a ZJS |
691 | int unlink_or_warn(const char *filename) { |
692 | if (unlink(filename) < 0 && errno != ENOENT) | |
693 | /* If the file doesn't exist and the fs simply was read-only (in which | |
694 | * case unlink() returns EROFS even if the file doesn't exist), don't | |
695 | * complain */ | |
696 | if (errno != EROFS || access(filename, F_OK) >= 0) | |
697 | return log_error_errno(errno, "Failed to remove \"%s\": %m", filename); | |
698 | ||
699 | return 0; | |
700 | } | |
701 | ||
430fbf8e | 702 | int inotify_add_watch_fd(int fd, int what, uint32_t mask) { |
fbd0b64f | 703 | char path[STRLEN("/proc/self/fd/") + DECIMAL_STR_MAX(int) + 1]; |
f6f4f5fe | 704 | int wd; |
430fbf8e LP |
705 | |
706 | /* This is like inotify_add_watch(), except that the file to watch is not referenced by a path, but by an fd */ | |
707 | xsprintf(path, "/proc/self/fd/%i", what); | |
708 | ||
f6f4f5fe BP |
709 | wd = inotify_add_watch(fd, path, mask); |
710 | if (wd < 0) | |
430fbf8e LP |
711 | return -errno; |
712 | ||
f6f4f5fe | 713 | return wd; |
430fbf8e | 714 | } |
d944dc95 | 715 | |
27c3112d | 716 | int inotify_add_watch_and_warn(int fd, const char *pathname, uint32_t mask) { |
f6f4f5fe | 717 | int wd; |
27c3112d | 718 | |
f6f4f5fe BP |
719 | wd = inotify_add_watch(fd, pathname, mask); |
720 | if (wd < 0) { | |
27c3112d | 721 | if (errno == ENOSPC) |
fe573a79 | 722 | return log_error_errno(errno, "Failed to add a watch for %s: inotify watch limit reached", pathname); |
27c3112d | 723 | |
fe573a79 | 724 | return log_error_errno(errno, "Failed to add a watch for %s: %m", pathname); |
27c3112d FB |
725 | } |
726 | ||
f6f4f5fe | 727 | return wd; |
27c3112d FB |
728 | } |
729 | ||
b85ee2ec | 730 | static bool unsafe_transition(const struct stat *a, const struct stat *b) { |
f14f1806 LP |
731 | /* Returns true if the transition from a to b is safe, i.e. that we never transition from unprivileged to |
732 | * privileged files or directories. Why bother? So that unprivileged code can't symlink to privileged files | |
733 | * making us believe we read something safe even though it isn't safe in the specific context we open it in. */ | |
734 | ||
735 | if (a->st_uid == 0) /* Transitioning from privileged to unprivileged is always fine */ | |
b85ee2ec | 736 | return false; |
f14f1806 | 737 | |
b85ee2ec | 738 | return a->st_uid != b->st_uid; /* Otherwise we need to stay within the same UID */ |
f14f1806 LP |
739 | } |
740 | ||
fd74c6f3 FB |
741 | static int log_unsafe_transition(int a, int b, const char *path, unsigned flags) { |
742 | _cleanup_free_ char *n1 = NULL, *n2 = NULL; | |
743 | ||
744 | if (!FLAGS_SET(flags, CHASE_WARN)) | |
36c97dec | 745 | return -ENOLINK; |
fd74c6f3 FB |
746 | |
747 | (void) fd_get_path(a, &n1); | |
748 | (void) fd_get_path(b, &n2); | |
749 | ||
36c97dec | 750 | return log_warning_errno(SYNTHETIC_ERRNO(ENOLINK), |
fd74c6f3 | 751 | "Detected unsafe path transition %s %s %s during canonicalization of %s.", |
9a6f746f | 752 | n1, special_glyph(SPECIAL_GLYPH_ARROW), n2, path); |
fd74c6f3 FB |
753 | } |
754 | ||
145b8d0f FB |
755 | static int log_autofs_mount_point(int fd, const char *path, unsigned flags) { |
756 | _cleanup_free_ char *n1 = NULL; | |
757 | ||
758 | if (!FLAGS_SET(flags, CHASE_WARN)) | |
759 | return -EREMOTE; | |
760 | ||
761 | (void) fd_get_path(fd, &n1); | |
762 | ||
763 | return log_warning_errno(SYNTHETIC_ERRNO(EREMOTE), | |
764 | "Detected autofs mount point %s during canonicalization of %s.", | |
765 | n1, path); | |
f14f1806 LP |
766 | } |
767 | ||
a5648b80 | 768 | int chase_symlinks(const char *path, const char *original_root, unsigned flags, char **ret_path, int *ret_fd) { |
d944dc95 LP |
769 | _cleanup_free_ char *buffer = NULL, *done = NULL, *root = NULL; |
770 | _cleanup_close_ int fd = -1; | |
f10f4215 | 771 | unsigned max_follow = CHASE_SYMLINKS_MAX; /* how many symlinks to follow before giving up and returning ELOOP */ |
f14f1806 | 772 | struct stat previous_stat; |
a9fb0867 | 773 | bool exists = true; |
d944dc95 LP |
774 | char *todo; |
775 | int r; | |
776 | ||
777 | assert(path); | |
778 | ||
1ed34d75 | 779 | /* Either the file may be missing, or we return an fd to the final object, but both make no sense */ |
a5648b80 | 780 | if ((flags & CHASE_NONEXISTENT) && ret_fd) |
1ed34d75 LP |
781 | return -EINVAL; |
782 | ||
a5648b80 | 783 | if ((flags & CHASE_STEP) && ret_fd) |
49eb3659 LP |
784 | return -EINVAL; |
785 | ||
a49424af LP |
786 | if (isempty(path)) |
787 | return -EINVAL; | |
788 | ||
d944dc95 LP |
789 | /* This is a lot like canonicalize_file_name(), but takes an additional "root" parameter, that allows following |
790 | * symlinks relative to a root directory, instead of the root of the host. | |
791 | * | |
fc4b68e5 | 792 | * Note that "root" primarily matters if we encounter an absolute symlink. It is also used when following |
c4f4fce7 LP |
793 | * relative symlinks to ensure they cannot be used to "escape" the root directory. The path parameter passed is |
794 | * assumed to be already prefixed by it, except if the CHASE_PREFIX_ROOT flag is set, in which case it is first | |
795 | * prefixed accordingly. | |
d944dc95 LP |
796 | * |
797 | * Algorithmically this operates on two path buffers: "done" are the components of the path we already | |
798 | * processed and resolved symlinks, "." and ".." of. "todo" are the components of the path we still need to | |
799 | * process. On each iteration, we move one component from "todo" to "done", processing it's special meaning | |
800 | * each time. The "todo" path always starts with at least one slash, the "done" path always ends in no | |
801 | * slash. We always keep an O_PATH fd to the component we are currently processing, thus keeping lookup races | |
4293c32b | 802 | * to a minimum. |
fc4b68e5 LP |
803 | * |
804 | * Suggested usage: whenever you want to canonicalize a path, use this function. Pass the absolute path you got | |
805 | * as-is: fully qualified and relative to your host's root. Optionally, specify the root parameter to tell this | |
806 | * function what to do when encountering a symlink with an absolute path as directory: prefix it by the | |
49eb3659 LP |
807 | * specified path. |
808 | * | |
a5648b80 | 809 | * There are five ways to invoke this function: |
49eb3659 | 810 | * |
a5648b80 ZJS |
811 | * 1. Without CHASE_STEP or ret_fd: in this case the path is resolved and the normalized path is |
812 | * returned in `ret_path`. The return value is < 0 on error. If CHASE_NONEXISTENT is also set, 0 | |
813 | * is returned if the file doesn't exist, > 0 otherwise. If CHASE_NONEXISTENT is not set, >= 0 is | |
814 | * returned if the destination was found, -ENOENT if it wasn't. | |
49eb3659 | 815 | * |
a5648b80 | 816 | * 2. With ret_fd: in this case the destination is opened after chasing it as O_PATH and this file |
49eb3659 LP |
817 | * descriptor is returned as return value. This is useful to open files relative to some root |
818 | * directory. Note that the returned O_PATH file descriptors must be converted into a regular one (using | |
a5648b80 | 819 | * fd_reopen() or such) before it can be used for reading/writing. ret_fd may not be combined with |
49eb3659 LP |
820 | * CHASE_NONEXISTENT. |
821 | * | |
822 | * 3. With CHASE_STEP: in this case only a single step of the normalization is executed, i.e. only the first | |
823 | * symlink or ".." component of the path is resolved, and the resulting path is returned. This is useful if | |
824 | * a caller wants to trace the a path through the file system verbosely. Returns < 0 on error, > 0 if the | |
825 | * path is fully normalized, and == 0 for each normalization step. This may be combined with | |
826 | * CHASE_NONEXISTENT, in which case 1 is returned when a component is not found. | |
827 | * | |
36c97dec FB |
828 | * 4. With CHASE_SAFE: in this case the path must not contain unsafe transitions, i.e. transitions from |
829 | * unprivileged to privileged files or directories. In such cases the return value is -ENOLINK. If | |
4293c32b | 830 | * CHASE_WARN is also set, a warning describing the unsafe transition is emitted. |
36c97dec | 831 | * |
4293c32b ZJS |
832 | * 5. With CHASE_NO_AUTOFS: in this case if an autofs mount point is encountered, path normalization |
833 | * is aborted and -EREMOTE is returned. If CHASE_WARN is also set, a warning showing the path of | |
834 | * the mount point is emitted. | |
4293c32b | 835 | */ |
d944dc95 | 836 | |
22bc57c5 | 837 | /* A root directory of "/" or "" is identical to none */ |
57ea45e1 | 838 | if (empty_or_root(original_root)) |
22bc57c5 | 839 | original_root = NULL; |
b1bfb848 | 840 | |
a5648b80 ZJS |
841 | if (!original_root && !ret_path && !(flags & (CHASE_NONEXISTENT|CHASE_NO_AUTOFS|CHASE_SAFE|CHASE_STEP)) && ret_fd) { |
842 | /* Shortcut the ret_fd case if the caller isn't interested in the actual path and has no root set | |
244d2f07 | 843 | * and doesn't care about any of the other special features we provide either. */ |
1f56e4ce | 844 | r = open(path, O_PATH|O_CLOEXEC|((flags & CHASE_NOFOLLOW) ? O_NOFOLLOW : 0)); |
244d2f07 LP |
845 | if (r < 0) |
846 | return -errno; | |
847 | ||
a5648b80 ZJS |
848 | *ret_fd = r; |
849 | return 0; | |
244d2f07 LP |
850 | } |
851 | ||
c4f4fce7 LP |
852 | if (original_root) { |
853 | r = path_make_absolute_cwd(original_root, &root); | |
d944dc95 LP |
854 | if (r < 0) |
855 | return r; | |
c4f4fce7 | 856 | |
47d7ab72 LP |
857 | /* Simplify the root directory, so that it has no duplicate slashes and nothing at the |
858 | * end. While we won't resolve the root path we still simplify it. Note that dropping the | |
859 | * trailing slash should not change behaviour, since when opening it we specify O_DIRECTORY | |
860 | * anyway. Moreover at the end of this function after processing everything we'll always turn | |
861 | * the empty string back to "/". */ | |
862 | delete_trailing_chars(root, "/"); | |
863 | path_simplify(root, true); | |
864 | ||
382a5078 | 865 | if (flags & CHASE_PREFIX_ROOT) { |
382a5078 LP |
866 | /* We don't support relative paths in combination with a root directory */ |
867 | if (!path_is_absolute(path)) | |
868 | return -EINVAL; | |
869 | ||
c4f4fce7 | 870 | path = prefix_roota(root, path); |
382a5078 | 871 | } |
d944dc95 LP |
872 | } |
873 | ||
c4f4fce7 LP |
874 | r = path_make_absolute_cwd(path, &buffer); |
875 | if (r < 0) | |
876 | return r; | |
877 | ||
c2595d3b | 878 | fd = open(root ?: "/", O_CLOEXEC|O_DIRECTORY|O_PATH); |
d944dc95 LP |
879 | if (fd < 0) |
880 | return -errno; | |
881 | ||
f14f1806 LP |
882 | if (flags & CHASE_SAFE) { |
883 | if (fstat(fd, &previous_stat) < 0) | |
884 | return -errno; | |
885 | } | |
886 | ||
c2595d3b LP |
887 | if (root) { |
888 | _cleanup_free_ char *absolute = NULL; | |
889 | const char *e; | |
890 | ||
891 | /* If we are operating on a root directory, let's take the root directory as it is. */ | |
892 | ||
893 | e = path_startswith(buffer, root); | |
894 | if (!e) | |
895 | return log_full_errno(flags & CHASE_WARN ? LOG_WARNING : LOG_DEBUG, | |
896 | SYNTHETIC_ERRNO(ECHRNG), | |
897 | "Specified path '%s' is outside of specified root directory '%s', refusing to resolve.", | |
898 | path, root); | |
899 | ||
c2595d3b LP |
900 | done = strdup(root); |
901 | if (!done) | |
902 | return -ENOMEM; | |
c2595d3b LP |
903 | |
904 | /* Make sure "todo" starts with a slash */ | |
905 | absolute = strjoin("/", e); | |
906 | if (!absolute) | |
907 | return -ENOMEM; | |
908 | ||
909 | free_and_replace(buffer, absolute); | |
910 | } | |
911 | ||
d944dc95 LP |
912 | todo = buffer; |
913 | for (;;) { | |
914 | _cleanup_free_ char *first = NULL; | |
915 | _cleanup_close_ int child = -1; | |
916 | struct stat st; | |
917 | size_t n, m; | |
918 | ||
919 | /* Determine length of first component in the path */ | |
920 | n = strspn(todo, "/"); /* The slashes */ | |
47d7ab72 LP |
921 | |
922 | if (n > 1) { | |
923 | /* If we are looking at more than a single slash then skip all but one, so that when | |
924 | * we are done with everything we have a normalized path with only single slashes | |
925 | * separating the path components. */ | |
926 | todo += n - 1; | |
927 | n = 1; | |
928 | } | |
929 | ||
d944dc95 LP |
930 | m = n + strcspn(todo + n, "/"); /* The entire length of the component */ |
931 | ||
932 | /* Extract the first component. */ | |
933 | first = strndup(todo, m); | |
934 | if (!first) | |
935 | return -ENOMEM; | |
936 | ||
937 | todo += m; | |
938 | ||
b12d25a8 ZJS |
939 | /* Empty? Then we reached the end. */ |
940 | if (isempty(first)) | |
941 | break; | |
942 | ||
d944dc95 | 943 | /* Just a single slash? Then we reached the end. */ |
b12d25a8 ZJS |
944 | if (path_equal(first, "/")) { |
945 | /* Preserve the trailing slash */ | |
62570f6f LP |
946 | |
947 | if (flags & CHASE_TRAIL_SLASH) | |
948 | if (!strextend(&done, "/", NULL)) | |
949 | return -ENOMEM; | |
b12d25a8 | 950 | |
d944dc95 | 951 | break; |
b12d25a8 | 952 | } |
d944dc95 LP |
953 | |
954 | /* Just a dot? Then let's eat this up. */ | |
955 | if (path_equal(first, "/.")) | |
956 | continue; | |
957 | ||
958 | /* Two dots? Then chop off the last bit of what we already found out. */ | |
959 | if (path_equal(first, "/..")) { | |
960 | _cleanup_free_ char *parent = NULL; | |
2b6d2dda | 961 | _cleanup_close_ int fd_parent = -1; |
d944dc95 | 962 | |
a4eaf3cf LP |
963 | /* If we already are at the top, then going up will not change anything. This is in-line with |
964 | * how the kernel handles this. */ | |
57ea45e1 | 965 | if (empty_or_root(done)) |
a4eaf3cf | 966 | continue; |
d944dc95 LP |
967 | |
968 | parent = dirname_malloc(done); | |
969 | if (!parent) | |
970 | return -ENOMEM; | |
971 | ||
a4eaf3cf | 972 | /* Don't allow this to leave the root dir. */ |
d944dc95 LP |
973 | if (root && |
974 | path_startswith(done, root) && | |
975 | !path_startswith(parent, root)) | |
a4eaf3cf | 976 | continue; |
d944dc95 | 977 | |
3b319885 | 978 | free_and_replace(done, parent); |
d944dc95 | 979 | |
49eb3659 LP |
980 | if (flags & CHASE_STEP) |
981 | goto chased_one; | |
982 | ||
d944dc95 LP |
983 | fd_parent = openat(fd, "..", O_CLOEXEC|O_NOFOLLOW|O_PATH); |
984 | if (fd_parent < 0) | |
985 | return -errno; | |
986 | ||
f14f1806 LP |
987 | if (flags & CHASE_SAFE) { |
988 | if (fstat(fd_parent, &st) < 0) | |
989 | return -errno; | |
990 | ||
b85ee2ec | 991 | if (unsafe_transition(&previous_stat, &st)) |
fd74c6f3 | 992 | return log_unsafe_transition(fd, fd_parent, path, flags); |
f14f1806 LP |
993 | |
994 | previous_stat = st; | |
995 | } | |
996 | ||
d944dc95 | 997 | safe_close(fd); |
c10d6bdb | 998 | fd = TAKE_FD(fd_parent); |
d944dc95 LP |
999 | |
1000 | continue; | |
1001 | } | |
1002 | ||
1003 | /* Otherwise let's see what this is. */ | |
1004 | child = openat(fd, first + n, O_CLOEXEC|O_NOFOLLOW|O_PATH); | |
a9fb0867 LP |
1005 | if (child < 0) { |
1006 | ||
1007 | if (errno == ENOENT && | |
cb638b5e | 1008 | (flags & CHASE_NONEXISTENT) && |
99be45a4 | 1009 | (isempty(todo) || path_is_normalized(todo))) { |
a9fb0867 | 1010 | |
cb638b5e | 1011 | /* If CHASE_NONEXISTENT is set, and the path does not exist, then that's OK, return |
a9fb0867 LP |
1012 | * what we got so far. But don't allow this if the remaining path contains "../ or "./" |
1013 | * or something else weird. */ | |
1014 | ||
a1904a46 YW |
1015 | /* If done is "/", as first also contains slash at the head, then remove this redundant slash. */ |
1016 | if (streq_ptr(done, "/")) | |
1017 | *done = '\0'; | |
1018 | ||
a9fb0867 LP |
1019 | if (!strextend(&done, first, todo, NULL)) |
1020 | return -ENOMEM; | |
1021 | ||
1022 | exists = false; | |
1023 | break; | |
1024 | } | |
1025 | ||
d944dc95 | 1026 | return -errno; |
a9fb0867 | 1027 | } |
d944dc95 LP |
1028 | |
1029 | if (fstat(child, &st) < 0) | |
1030 | return -errno; | |
f14f1806 | 1031 | if ((flags & CHASE_SAFE) && |
b85ee2ec | 1032 | unsafe_transition(&previous_stat, &st)) |
fd74c6f3 | 1033 | return log_unsafe_transition(fd, child, path, flags); |
f14f1806 LP |
1034 | |
1035 | previous_stat = st; | |
1036 | ||
655f2da0 | 1037 | if ((flags & CHASE_NO_AUTOFS) && |
a66fee2e | 1038 | fd_is_fs_type(child, AUTOFS_SUPER_MAGIC) > 0) |
145b8d0f | 1039 | return log_autofs_mount_point(child, path, flags); |
d944dc95 | 1040 | |
1f56e4ce | 1041 | if (S_ISLNK(st.st_mode) && !((flags & CHASE_NOFOLLOW) && isempty(todo))) { |
877777d7 | 1042 | char *joined; |
d944dc95 LP |
1043 | _cleanup_free_ char *destination = NULL; |
1044 | ||
1045 | /* This is a symlink, in this case read the destination. But let's make sure we don't follow | |
1046 | * symlinks without bounds. */ | |
1047 | if (--max_follow <= 0) | |
1048 | return -ELOOP; | |
1049 | ||
1050 | r = readlinkat_malloc(fd, first + n, &destination); | |
1051 | if (r < 0) | |
1052 | return r; | |
1053 | if (isempty(destination)) | |
1054 | return -EINVAL; | |
1055 | ||
1056 | if (path_is_absolute(destination)) { | |
1057 | ||
1058 | /* An absolute destination. Start the loop from the beginning, but use the root | |
1059 | * directory as base. */ | |
1060 | ||
1061 | safe_close(fd); | |
c2595d3b | 1062 | fd = open(root ?: "/", O_CLOEXEC|O_DIRECTORY|O_PATH); |
d944dc95 LP |
1063 | if (fd < 0) |
1064 | return -errno; | |
1065 | ||
f14f1806 LP |
1066 | if (flags & CHASE_SAFE) { |
1067 | if (fstat(fd, &st) < 0) | |
1068 | return -errno; | |
1069 | ||
b85ee2ec | 1070 | if (unsafe_transition(&previous_stat, &st)) |
fd74c6f3 | 1071 | return log_unsafe_transition(child, fd, path, flags); |
f14f1806 LP |
1072 | |
1073 | previous_stat = st; | |
1074 | } | |
1075 | ||
b539437a YW |
1076 | free(done); |
1077 | ||
d944dc95 LP |
1078 | /* Note that we do not revalidate the root, we take it as is. */ |
1079 | if (isempty(root)) | |
1080 | done = NULL; | |
1081 | else { | |
1082 | done = strdup(root); | |
1083 | if (!done) | |
1084 | return -ENOMEM; | |
1085 | } | |
1086 | ||
8c4a8ea2 LP |
1087 | /* Prefix what's left to do with what we just read, and start the loop again, but |
1088 | * remain in the current directory. */ | |
2d9b74ba | 1089 | joined = path_join(destination, todo); |
8c4a8ea2 | 1090 | } else |
2d9b74ba | 1091 | joined = path_join("/", destination, todo); |
877777d7 CCW |
1092 | if (!joined) |
1093 | return -ENOMEM; | |
d944dc95 | 1094 | |
877777d7 CCW |
1095 | free(buffer); |
1096 | todo = buffer = joined; | |
d944dc95 | 1097 | |
49eb3659 LP |
1098 | if (flags & CHASE_STEP) |
1099 | goto chased_one; | |
1100 | ||
d944dc95 LP |
1101 | continue; |
1102 | } | |
1103 | ||
1104 | /* If this is not a symlink, then let's just add the name we read to what we already verified. */ | |
ae2a15bc LP |
1105 | if (!done) |
1106 | done = TAKE_PTR(first); | |
1107 | else { | |
a1904a46 YW |
1108 | /* If done is "/", as first also contains slash at the head, then remove this redundant slash. */ |
1109 | if (streq(done, "/")) | |
1110 | *done = '\0'; | |
1111 | ||
d944dc95 LP |
1112 | if (!strextend(&done, first, NULL)) |
1113 | return -ENOMEM; | |
1114 | } | |
1115 | ||
1116 | /* And iterate again, but go one directory further down. */ | |
1117 | safe_close(fd); | |
c10d6bdb | 1118 | fd = TAKE_FD(child); |
d944dc95 LP |
1119 | } |
1120 | ||
1121 | if (!done) { | |
1122 | /* Special case, turn the empty string into "/", to indicate the root directory. */ | |
1123 | done = strdup("/"); | |
1124 | if (!done) | |
1125 | return -ENOMEM; | |
1126 | } | |
1127 | ||
a5648b80 ZJS |
1128 | if (ret_path) |
1129 | *ret_path = TAKE_PTR(done); | |
d944dc95 | 1130 | |
a5648b80 ZJS |
1131 | if (ret_fd) { |
1132 | /* Return the O_PATH fd we currently are looking to the caller. It can translate it to a | |
1133 | * proper fd by opening /proc/self/fd/xyz. */ | |
1ed34d75 LP |
1134 | |
1135 | assert(fd >= 0); | |
a5648b80 | 1136 | *ret_fd = TAKE_FD(fd); |
1ed34d75 LP |
1137 | } |
1138 | ||
49eb3659 LP |
1139 | if (flags & CHASE_STEP) |
1140 | return 1; | |
1141 | ||
a9fb0867 | 1142 | return exists; |
49eb3659 LP |
1143 | |
1144 | chased_one: | |
a5648b80 | 1145 | if (ret_path) { |
49eb3659 LP |
1146 | char *c; |
1147 | ||
027cc9c9 ZJS |
1148 | c = strjoin(strempty(done), todo); |
1149 | if (!c) | |
1150 | return -ENOMEM; | |
49eb3659 | 1151 | |
a5648b80 | 1152 | *ret_path = c; |
49eb3659 LP |
1153 | } |
1154 | ||
1155 | return 0; | |
d944dc95 | 1156 | } |
57a4359e | 1157 | |
21c692e9 LP |
1158 | int chase_symlinks_and_open( |
1159 | const char *path, | |
1160 | const char *root, | |
1161 | unsigned chase_flags, | |
1162 | int open_flags, | |
1163 | char **ret_path) { | |
1164 | ||
1165 | _cleanup_close_ int path_fd = -1; | |
1166 | _cleanup_free_ char *p = NULL; | |
1167 | int r; | |
1168 | ||
1169 | if (chase_flags & CHASE_NONEXISTENT) | |
1170 | return -EINVAL; | |
1171 | ||
57ea45e1 | 1172 | if (empty_or_root(root) && !ret_path && (chase_flags & (CHASE_NO_AUTOFS|CHASE_SAFE)) == 0) { |
21c692e9 LP |
1173 | /* Shortcut this call if none of the special features of this call are requested */ |
1174 | r = open(path, open_flags); | |
1175 | if (r < 0) | |
1176 | return -errno; | |
1177 | ||
1178 | return r; | |
1179 | } | |
1180 | ||
a5648b80 ZJS |
1181 | r = chase_symlinks(path, root, chase_flags, ret_path ? &p : NULL, &path_fd); |
1182 | if (r < 0) | |
1183 | return r; | |
1184 | assert(path_fd >= 0); | |
21c692e9 LP |
1185 | |
1186 | r = fd_reopen(path_fd, open_flags); | |
1187 | if (r < 0) | |
1188 | return r; | |
1189 | ||
1190 | if (ret_path) | |
1191 | *ret_path = TAKE_PTR(p); | |
1192 | ||
1193 | return r; | |
1194 | } | |
1195 | ||
1196 | int chase_symlinks_and_opendir( | |
1197 | const char *path, | |
1198 | const char *root, | |
1199 | unsigned chase_flags, | |
1200 | char **ret_path, | |
1201 | DIR **ret_dir) { | |
1202 | ||
1203 | char procfs_path[STRLEN("/proc/self/fd/") + DECIMAL_STR_MAX(int)]; | |
1204 | _cleanup_close_ int path_fd = -1; | |
1205 | _cleanup_free_ char *p = NULL; | |
1206 | DIR *d; | |
a5648b80 | 1207 | int r; |
21c692e9 LP |
1208 | |
1209 | if (!ret_dir) | |
1210 | return -EINVAL; | |
1211 | if (chase_flags & CHASE_NONEXISTENT) | |
1212 | return -EINVAL; | |
1213 | ||
57ea45e1 | 1214 | if (empty_or_root(root) && !ret_path && (chase_flags & (CHASE_NO_AUTOFS|CHASE_SAFE)) == 0) { |
21c692e9 LP |
1215 | /* Shortcut this call if none of the special features of this call are requested */ |
1216 | d = opendir(path); | |
1217 | if (!d) | |
1218 | return -errno; | |
1219 | ||
1220 | *ret_dir = d; | |
1221 | return 0; | |
1222 | } | |
1223 | ||
a5648b80 ZJS |
1224 | r = chase_symlinks(path, root, chase_flags, ret_path ? &p : NULL, &path_fd); |
1225 | if (r < 0) | |
1226 | return r; | |
1227 | assert(path_fd >= 0); | |
21c692e9 LP |
1228 | |
1229 | xsprintf(procfs_path, "/proc/self/fd/%i", path_fd); | |
1230 | d = opendir(procfs_path); | |
1231 | if (!d) | |
1232 | return -errno; | |
1233 | ||
1234 | if (ret_path) | |
1235 | *ret_path = TAKE_PTR(p); | |
1236 | ||
1237 | *ret_dir = d; | |
1238 | return 0; | |
1239 | } | |
1240 | ||
d2bcd0ba LP |
1241 | int chase_symlinks_and_stat( |
1242 | const char *path, | |
1243 | const char *root, | |
1244 | unsigned chase_flags, | |
1245 | char **ret_path, | |
a5648b80 ZJS |
1246 | struct stat *ret_stat, |
1247 | int *ret_fd) { | |
d2bcd0ba LP |
1248 | |
1249 | _cleanup_close_ int path_fd = -1; | |
1250 | _cleanup_free_ char *p = NULL; | |
a5648b80 | 1251 | int r; |
d2bcd0ba LP |
1252 | |
1253 | assert(path); | |
1254 | assert(ret_stat); | |
1255 | ||
1256 | if (chase_flags & CHASE_NONEXISTENT) | |
1257 | return -EINVAL; | |
1258 | ||
1259 | if (empty_or_root(root) && !ret_path && (chase_flags & (CHASE_NO_AUTOFS|CHASE_SAFE)) == 0) { | |
1260 | /* Shortcut this call if none of the special features of this call are requested */ | |
1261 | if (stat(path, ret_stat) < 0) | |
1262 | return -errno; | |
1263 | ||
1264 | return 1; | |
1265 | } | |
1266 | ||
a5648b80 ZJS |
1267 | r = chase_symlinks(path, root, chase_flags, ret_path ? &p : NULL, &path_fd); |
1268 | if (r < 0) | |
1269 | return r; | |
1270 | assert(path_fd >= 0); | |
d2bcd0ba LP |
1271 | |
1272 | if (fstat(path_fd, ret_stat) < 0) | |
1273 | return -errno; | |
1274 | ||
1275 | if (ret_path) | |
1276 | *ret_path = TAKE_PTR(p); | |
a5648b80 ZJS |
1277 | if (ret_fd) |
1278 | *ret_fd = TAKE_FD(path_fd); | |
d2bcd0ba LP |
1279 | |
1280 | return 1; | |
1281 | } | |
1282 | ||
57a4359e | 1283 | int access_fd(int fd, int mode) { |
fbd0b64f | 1284 | char p[STRLEN("/proc/self/fd/") + DECIMAL_STR_MAX(fd) + 1]; |
57a4359e LP |
1285 | int r; |
1286 | ||
1287 | /* Like access() but operates on an already open fd */ | |
1288 | ||
1289 | xsprintf(p, "/proc/self/fd/%i", fd); | |
57a4359e LP |
1290 | r = access(p, mode); |
1291 | if (r < 0) | |
21c692e9 | 1292 | return -errno; |
57a4359e LP |
1293 | |
1294 | return r; | |
1295 | } | |
43767d9d | 1296 | |
627d2bac ZJS |
1297 | void unlink_tempfilep(char (*p)[]) { |
1298 | /* If the file is created with mkstemp(), it will (almost always) | |
1299 | * change the suffix. Treat this as a sign that the file was | |
1300 | * successfully created. We ignore both the rare case where the | |
1301 | * original suffix is used and unlink failures. */ | |
1302 | if (!endswith(*p, ".XXXXXX")) | |
69821560 | 1303 | (void) unlink_noerrno(*p); |
627d2bac ZJS |
1304 | } |
1305 | ||
43767d9d LP |
1306 | int unlinkat_deallocate(int fd, const char *name, int flags) { |
1307 | _cleanup_close_ int truncate_fd = -1; | |
1308 | struct stat st; | |
1309 | off_t l, bs; | |
1310 | ||
1311 | /* Operates like unlinkat() but also deallocates the file contents if it is a regular file and there's no other | |
1312 | * link to it. This is useful to ensure that other processes that might have the file open for reading won't be | |
1313 | * able to keep the data pinned on disk forever. This call is particular useful whenever we execute clean-up | |
1314 | * jobs ("vacuuming"), where we want to make sure the data is really gone and the disk space released and | |
1315 | * returned to the free pool. | |
1316 | * | |
1317 | * Deallocation is preferably done by FALLOC_FL_PUNCH_HOLE|FALLOC_FL_KEEP_SIZE (👊) if supported, which means | |
1318 | * the file won't change size. That's a good thing since we shouldn't needlessly trigger SIGBUS in other | |
1319 | * programs that have mmap()ed the file. (The assumption here is that changing file contents to all zeroes | |
1320 | * underneath those programs is the better choice than simply triggering SIGBUS in them which truncation does.) | |
1321 | * However if hole punching is not implemented in the kernel or file system we'll fall back to normal file | |
1322 | * truncation (🔪), as our goal of deallocating the data space trumps our goal of being nice to readers (💐). | |
1323 | * | |
1324 | * Note that we attempt deallocation, but failure to succeed with that is not considered fatal, as long as the | |
1325 | * primary job – to delete the file – is accomplished. */ | |
1326 | ||
1327 | if ((flags & AT_REMOVEDIR) == 0) { | |
1328 | truncate_fd = openat(fd, name, O_WRONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW|O_NONBLOCK); | |
1329 | if (truncate_fd < 0) { | |
1330 | ||
1331 | /* If this failed because the file doesn't exist propagate the error right-away. Also, | |
1332 | * AT_REMOVEDIR wasn't set, and we tried to open the file for writing, which means EISDIR is | |
1333 | * returned when this is a directory but we are not supposed to delete those, hence propagate | |
1334 | * the error right-away too. */ | |
1335 | if (IN_SET(errno, ENOENT, EISDIR)) | |
1336 | return -errno; | |
1337 | ||
1338 | if (errno != ELOOP) /* don't complain if this is a symlink */ | |
1339 | log_debug_errno(errno, "Failed to open file '%s' for deallocation, ignoring: %m", name); | |
1340 | } | |
1341 | } | |
1342 | ||
1343 | if (unlinkat(fd, name, flags) < 0) | |
1344 | return -errno; | |
1345 | ||
1346 | if (truncate_fd < 0) /* Don't have a file handle, can't do more ☹️ */ | |
1347 | return 0; | |
1348 | ||
1349 | if (fstat(truncate_fd, &st) < 0) { | |
011723a4 | 1350 | log_debug_errno(errno, "Failed to stat file '%s' for deallocation, ignoring: %m", name); |
43767d9d LP |
1351 | return 0; |
1352 | } | |
1353 | ||
1354 | if (!S_ISREG(st.st_mode) || st.st_blocks == 0 || st.st_nlink > 0) | |
1355 | return 0; | |
1356 | ||
1357 | /* If this is a regular file, it actually took up space on disk and there are no other links it's time to | |
1358 | * punch-hole/truncate this to release the disk space. */ | |
1359 | ||
1360 | bs = MAX(st.st_blksize, 512); | |
1361 | l = DIV_ROUND_UP(st.st_size, bs) * bs; /* Round up to next block size */ | |
1362 | ||
1363 | if (fallocate(truncate_fd, FALLOC_FL_PUNCH_HOLE|FALLOC_FL_KEEP_SIZE, 0, l) >= 0) | |
1364 | return 0; /* Successfully punched a hole! 😊 */ | |
1365 | ||
1366 | /* Fall back to truncation */ | |
1367 | if (ftruncate(truncate_fd, 0) < 0) { | |
1368 | log_debug_errno(errno, "Failed to truncate file to 0, ignoring: %m"); | |
1369 | return 0; | |
1370 | } | |
1371 | ||
1372 | return 0; | |
1373 | } | |
11b29a96 LP |
1374 | |
1375 | int fsync_directory_of_file(int fd) { | |
0c462ea4 | 1376 | _cleanup_free_ char *path = NULL; |
11b29a96 LP |
1377 | _cleanup_close_ int dfd = -1; |
1378 | int r; | |
1379 | ||
1380 | r = fd_verify_regular(fd); | |
1381 | if (r < 0) | |
1382 | return r; | |
1383 | ||
1384 | r = fd_get_path(fd, &path); | |
3ceae1bc | 1385 | if (r < 0) { |
b8b846d7 LP |
1386 | log_debug_errno(r, "Failed to query /proc/self/fd/%d%s: %m", |
1387 | fd, | |
1388 | r == -EOPNOTSUPP ? ", ignoring" : ""); | |
3ceae1bc ZJS |
1389 | |
1390 | if (r == -EOPNOTSUPP) | |
1391 | /* If /proc is not available, we're most likely running in some | |
1392 | * chroot environment, and syncing the directory is not very | |
1393 | * important in that case. Let's just silently do nothing. */ | |
1394 | return 0; | |
1395 | ||
11b29a96 | 1396 | return r; |
3ceae1bc | 1397 | } |
11b29a96 LP |
1398 | |
1399 | if (!path_is_absolute(path)) | |
1400 | return -EINVAL; | |
1401 | ||
0c462ea4 | 1402 | dfd = open_parent(path, O_CLOEXEC, 0); |
11b29a96 | 1403 | if (dfd < 0) |
0c462ea4 | 1404 | return dfd; |
11b29a96 LP |
1405 | |
1406 | if (fsync(dfd) < 0) | |
1407 | return -errno; | |
1408 | ||
1409 | return 0; | |
1410 | } | |
ef8becfa | 1411 | |
63d59b8d LP |
1412 | int fsync_full(int fd) { |
1413 | int r, q; | |
1414 | ||
1415 | /* Sync both the file and the directory */ | |
1416 | ||
1417 | r = fsync(fd) < 0 ? -errno : 0; | |
1418 | q = fsync_directory_of_file(fd); | |
1419 | ||
1420 | return r < 0 ? r : q; | |
1421 | } | |
1422 | ||
36695e88 LP |
1423 | int fsync_path_at(int at_fd, const char *path) { |
1424 | _cleanup_close_ int opened_fd = -1; | |
1425 | int fd; | |
1426 | ||
1427 | if (isempty(path)) { | |
1428 | if (at_fd == AT_FDCWD) { | |
1429 | opened_fd = open(".", O_RDONLY|O_DIRECTORY|O_CLOEXEC); | |
1430 | if (opened_fd < 0) | |
1431 | return -errno; | |
1432 | ||
1433 | fd = opened_fd; | |
1434 | } else | |
1435 | fd = at_fd; | |
1436 | } else { | |
1437 | ||
1438 | opened_fd = openat(at_fd, path, O_RDONLY|O_CLOEXEC); | |
1439 | if (opened_fd < 0) | |
1440 | return -errno; | |
1441 | ||
1442 | fd = opened_fd; | |
1443 | } | |
1444 | ||
1445 | if (fsync(fd) < 0) | |
1446 | return -errno; | |
1447 | ||
1448 | return 0; | |
1449 | } | |
1450 | ||
71f51416 LP |
1451 | int syncfs_path(int atfd, const char *path) { |
1452 | _cleanup_close_ int fd = -1; | |
1453 | ||
1454 | assert(path); | |
1455 | ||
1456 | fd = openat(atfd, path, O_CLOEXEC|O_RDONLY|O_NONBLOCK); | |
1457 | if (fd < 0) | |
1458 | return -errno; | |
1459 | ||
1460 | if (syncfs(fd) < 0) | |
1461 | return -errno; | |
1462 | ||
1463 | return 0; | |
1464 | } | |
1465 | ||
ef8becfa LP |
1466 | int open_parent(const char *path, int flags, mode_t mode) { |
1467 | _cleanup_free_ char *parent = NULL; | |
1468 | int fd; | |
1469 | ||
1470 | if (isempty(path)) | |
1471 | return -EINVAL; | |
1472 | if (path_equal(path, "/")) /* requesting the parent of the root dir is fishy, let's prohibit that */ | |
1473 | return -EINVAL; | |
1474 | ||
1475 | parent = dirname_malloc(path); | |
1476 | if (!parent) | |
1477 | return -ENOMEM; | |
1478 | ||
1479 | /* Let's insist on O_DIRECTORY since the parent of a file or directory is a directory. Except if we open an | |
1480 | * O_TMPFILE file, because in that case we are actually create a regular file below the parent directory. */ | |
1481 | ||
0c21dafb | 1482 | if (FLAGS_SET(flags, O_PATH)) |
ef8becfa | 1483 | flags |= O_DIRECTORY; |
0c21dafb | 1484 | else if (!FLAGS_SET(flags, O_TMPFILE)) |
ef8becfa LP |
1485 | flags |= O_DIRECTORY|O_RDONLY; |
1486 | ||
1487 | fd = open(parent, flags, mode); | |
1488 | if (fd < 0) | |
1489 | return -errno; | |
1490 | ||
1491 | return fd; | |
1492 | } | |
ed9c0851 LP |
1493 | |
1494 | int path_is_encrypted(const char *path) { | |
1495 | _cleanup_free_ char *uuids = NULL; | |
1496 | char p[SYS_BLOCK_PATH_MAX("/dm/uuid")]; | |
1497 | dev_t devt; | |
1498 | int r; | |
1499 | ||
1500 | r = get_block_device(path, &devt); | |
1501 | if (r < 0) | |
1502 | return r; | |
1503 | if (r == 0) /* doesn't have a block device */ | |
1504 | return false; | |
1505 | ||
1506 | xsprintf_sys_block_path(p, "/dm/uuid", devt); | |
1507 | r = read_one_line_file(p, &uuids); | |
1508 | if (r == -ENOENT) | |
1509 | return false; | |
1510 | if (r < 0) | |
1511 | return r; | |
1512 | ||
1513 | /* The DM device's uuid attribute is prefixed with "CRYPT-" if this is a dm-crypt device. */ | |
1514 | return !!startswith(uuids, "CRYPT-"); | |
1515 | } |