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Commit | Line | Data |
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db9ecf05 | 1 | /* SPDX-License-Identifier: LGPL-2.1-or-later */ |
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" |
f4f15635 LP |
11 | #include "dirent-util.h" |
12 | #include "fd-util.h" | |
ed9c0851 | 13 | #include "fileio.h" |
f4f15635 | 14 | #include "fs-util.h" |
68def5a9 | 15 | #include "hostname-util.h" |
11c3a366 TA |
16 | #include "log.h" |
17 | #include "macro.h" | |
0499585f | 18 | #include "missing_fcntl.h" |
f5947a5e YW |
19 | #include "missing_fs.h" |
20 | #include "missing_syscall.h" | |
93cc7779 TA |
21 | #include "mkdir.h" |
22 | #include "parse-util.h" | |
23 | #include "path-util.h" | |
dccca82b | 24 | #include "process-util.h" |
053e0626 | 25 | #include "random-util.h" |
4c54768c | 26 | #include "ratelimit.h" |
34a8f081 | 27 | #include "stat-util.h" |
430fbf8e | 28 | #include "stdio-util.h" |
f4f15635 LP |
29 | #include "string-util.h" |
30 | #include "strv.h" | |
93cc7779 | 31 | #include "time-util.h" |
e4de7287 | 32 | #include "tmpfile-util.h" |
7c248223 | 33 | #include "umask-util.h" |
ee104e11 | 34 | #include "user-util.h" |
f4f15635 LP |
35 | |
36 | int unlink_noerrno(const char *path) { | |
37 | PROTECT_ERRNO; | |
7c248223 | 38 | return RET_NERRNO(unlink(path)); |
f4f15635 LP |
39 | } |
40 | ||
41 | int rmdir_parents(const char *path, const char *stop) { | |
4e046c5c YW |
42 | char *p; |
43 | int r; | |
f4f15635 LP |
44 | |
45 | assert(path); | |
46 | assert(stop); | |
47 | ||
4e046c5c YW |
48 | if (!path_is_safe(path)) |
49 | return -EINVAL; | |
f4f15635 | 50 | |
4e046c5c YW |
51 | if (!path_is_safe(stop)) |
52 | return -EINVAL; | |
f4f15635 | 53 | |
2f82562b | 54 | p = strdupa_safe(path); |
f4f15635 | 55 | |
4e046c5c YW |
56 | for (;;) { |
57 | char *slash = NULL; | |
f4f15635 | 58 | |
4e046c5c YW |
59 | /* skip the last component. */ |
60 | r = path_find_last_component(p, /* accept_dot_dot= */ false, (const char **) &slash, NULL); | |
61 | if (r <= 0) | |
62 | return r; | |
63 | if (slash == p) | |
64 | return 0; | |
f4f15635 | 65 | |
4e046c5c YW |
66 | assert(*slash == '/'); |
67 | *slash = '\0'; | |
f4f15635 | 68 | |
4e046c5c | 69 | if (path_startswith_full(stop, p, /* accept_dot_dot= */ false)) |
f4f15635 | 70 | return 0; |
f4f15635 | 71 | |
4e046c5c YW |
72 | if (rmdir(p) < 0 && errno != ENOENT) |
73 | return -errno; | |
f4f15635 | 74 | } |
f4f15635 LP |
75 | } |
76 | ||
f4f15635 | 77 | int rename_noreplace(int olddirfd, const char *oldpath, int newdirfd, const char *newpath) { |
2f15b625 | 78 | int r; |
f4f15635 | 79 | |
2f15b625 LP |
80 | /* Try the ideal approach first */ |
81 | if (renameat2(olddirfd, oldpath, newdirfd, newpath, RENAME_NOREPLACE) >= 0) | |
f4f15635 LP |
82 | return 0; |
83 | ||
2f15b625 LP |
84 | /* renameat2() exists since Linux 3.15, btrfs and FAT added support for it later. If it is not implemented, |
85 | * fall back to a different method. */ | |
62e10065 | 86 | if (!ERRNO_IS_NOT_SUPPORTED(errno) && errno != EINVAL) |
f4f15635 LP |
87 | return -errno; |
88 | ||
2f15b625 LP |
89 | /* Let's try to use linkat()+unlinkat() as fallback. This doesn't work on directories and on some file systems |
90 | * that do not support hard links (such as FAT, most prominently), but for files it's pretty close to what we | |
91 | * want — though not atomic (i.e. for a short period both the new and the old filename will exist). */ | |
92 | if (linkat(olddirfd, oldpath, newdirfd, newpath, 0) >= 0) { | |
93 | ||
7c248223 LP |
94 | r = RET_NERRNO(unlinkat(olddirfd, oldpath, 0)); |
95 | if (r < 0) { | |
2f15b625 LP |
96 | (void) unlinkat(newdirfd, newpath, 0); |
97 | return r; | |
98 | } | |
99 | ||
100 | return 0; | |
f4f15635 LP |
101 | } |
102 | ||
62e10065 | 103 | if (!ERRNO_IS_NOT_SUPPORTED(errno) && !IN_SET(errno, EINVAL, EPERM)) /* FAT returns EPERM on link()… */ |
f4f15635 LP |
104 | return -errno; |
105 | ||
2aed63f4 | 106 | /* OK, neither RENAME_NOREPLACE nor linkat()+unlinkat() worked. Let's then fall back to the racy TOCTOU |
2f15b625 LP |
107 | * vulnerable accessat(F_OK) check followed by classic, replacing renameat(), we have nothing better. */ |
108 | ||
109 | if (faccessat(newdirfd, newpath, F_OK, AT_SYMLINK_NOFOLLOW) >= 0) | |
110 | return -EEXIST; | |
111 | if (errno != ENOENT) | |
112 | return -errno; | |
113 | ||
7c248223 | 114 | return RET_NERRNO(renameat(olddirfd, oldpath, newdirfd, newpath)); |
f4f15635 LP |
115 | } |
116 | ||
117 | int readlinkat_malloc(int fd, const char *p, char **ret) { | |
db220032 | 118 | size_t l = PATH_MAX; |
f4f15635 LP |
119 | |
120 | assert(p); | |
f4f15635 LP |
121 | |
122 | for (;;) { | |
db220032 | 123 | _cleanup_free_ char *c = NULL; |
f4f15635 LP |
124 | ssize_t n; |
125 | ||
db220032 | 126 | c = new(char, l+1); |
f4f15635 LP |
127 | if (!c) |
128 | return -ENOMEM; | |
129 | ||
db220032 LP |
130 | n = readlinkat(fd, p, c, l); |
131 | if (n < 0) | |
132 | return -errno; | |
f4f15635 | 133 | |
db220032 | 134 | if ((size_t) n < l) { |
f4f15635 | 135 | c[n] = 0; |
aed3c5ec LP |
136 | |
137 | if (ret) | |
138 | *ret = TAKE_PTR(c); | |
139 | ||
f4f15635 LP |
140 | return 0; |
141 | } | |
142 | ||
db220032 LP |
143 | if (l > (SSIZE_MAX-1)/2) /* readlinkat() returns an ssize_t, and we want an extra byte for a |
144 | * trailing NUL, hence do an overflow check relative to SSIZE_MAX-1 | |
145 | * here */ | |
146 | return -EFBIG; | |
147 | ||
f4f15635 LP |
148 | l *= 2; |
149 | } | |
150 | } | |
151 | ||
152 | int readlink_malloc(const char *p, char **ret) { | |
153 | return readlinkat_malloc(AT_FDCWD, p, ret); | |
154 | } | |
155 | ||
156 | int readlink_value(const char *p, char **ret) { | |
bb60956b | 157 | _cleanup_free_ char *link = NULL, *name = NULL; |
f4f15635 LP |
158 | int r; |
159 | ||
ce8394f9 YW |
160 | assert(p); |
161 | assert(ret); | |
162 | ||
f4f15635 LP |
163 | r = readlink_malloc(p, &link); |
164 | if (r < 0) | |
165 | return r; | |
166 | ||
bb60956b YW |
167 | r = path_extract_filename(link, &name); |
168 | if (r < 0) | |
169 | return r; | |
170 | if (r == O_DIRECTORY) | |
171 | return -EINVAL; | |
172 | ||
173 | *ret = TAKE_PTR(name); | |
174 | return 0; | |
f4f15635 LP |
175 | } |
176 | ||
177 | int readlink_and_make_absolute(const char *p, char **r) { | |
178 | _cleanup_free_ char *target = NULL; | |
179 | char *k; | |
180 | int j; | |
181 | ||
182 | assert(p); | |
183 | assert(r); | |
184 | ||
185 | j = readlink_malloc(p, &target); | |
186 | if (j < 0) | |
187 | return j; | |
188 | ||
189 | k = file_in_same_dir(p, target); | |
190 | if (!k) | |
191 | return -ENOMEM; | |
192 | ||
193 | *r = k; | |
194 | return 0; | |
195 | } | |
196 | ||
55451417 | 197 | int chmod_and_chown_at(int dir_fd, const char *path, mode_t mode, uid_t uid, gid_t gid) { |
254d1313 | 198 | _cleanup_close_ int fd = -EBADF; |
30ff18d8 | 199 | |
7d000133 DDM |
200 | assert(dir_fd >= 0 || dir_fd == AT_FDCWD); |
201 | ||
55451417 DDM |
202 | if (path) { |
203 | /* Let's acquire an O_PATH fd, as precaution to change mode/owner on the same file */ | |
204 | fd = openat(dir_fd, path, O_PATH|O_CLOEXEC|O_NOFOLLOW); | |
205 | if (fd < 0) | |
206 | return -errno; | |
340bc268 YW |
207 | dir_fd = fd; |
208 | ||
209 | } else if (dir_fd == AT_FDCWD) { | |
210 | /* Let's acquire an O_PATH fd of the current directory */ | |
211 | fd = openat(dir_fd, ".", O_PATH|O_CLOEXEC|O_NOFOLLOW|O_DIRECTORY); | |
212 | if (fd < 0) | |
213 | return -errno; | |
214 | dir_fd = fd; | |
55451417 | 215 | } |
de321f52 | 216 | |
340bc268 | 217 | return fchmod_and_chown(dir_fd, mode, uid, gid); |
b8da477e YW |
218 | } |
219 | ||
0520564d | 220 | int fchmod_and_chown_with_fallback(int fd, const char *path, mode_t mode, uid_t uid, gid_t gid) { |
2dbb7e94 | 221 | bool do_chown, do_chmod; |
30ff18d8 | 222 | struct stat st; |
dee00c19 | 223 | int r; |
30ff18d8 | 224 | |
2dbb7e94 LP |
225 | /* Change ownership and access mode of the specified fd. Tries to do so safely, ensuring that at no |
226 | * point in time the access mode is above the old access mode under the old ownership or the new | |
227 | * access mode under the new ownership. Note: this call tries hard to leave the access mode | |
228 | * unaffected if the uid/gid is changed, i.e. it undoes implicit suid/sgid dropping the kernel does | |
229 | * on chown(). | |
230 | * | |
0520564d ZJS |
231 | * This call is happy with O_PATH fds. |
232 | * | |
233 | * If path is given, allow a fallback path which does not use /proc/self/fd/. On any normal system | |
234 | * /proc will be mounted, but in certain improperly assembled environments it might not be. This is | |
235 | * less secure (potential TOCTOU), so should only be used after consideration. */ | |
b8da477e | 236 | |
71ec74d1 | 237 | if (fstat(fd, &st) < 0) |
2dbb7e94 | 238 | return -errno; |
de321f52 | 239 | |
2dbb7e94 LP |
240 | do_chown = |
241 | (uid != UID_INVALID && st.st_uid != uid) || | |
242 | (gid != GID_INVALID && st.st_gid != gid); | |
de321f52 | 243 | |
2dbb7e94 LP |
244 | do_chmod = |
245 | !S_ISLNK(st.st_mode) && /* chmod is not defined on symlinks */ | |
246 | ((mode != MODE_INVALID && ((st.st_mode ^ mode) & 07777) != 0) || | |
247 | do_chown); /* If we change ownership, make sure we reset the mode afterwards, since chown() | |
248 | * modifies the access mode too */ | |
30ff18d8 | 249 | |
2dbb7e94 LP |
250 | if (mode == MODE_INVALID) |
251 | mode = st.st_mode; /* If we only shall do a chown(), save original mode, since chown() might break it. */ | |
252 | else if ((mode & S_IFMT) != 0 && ((mode ^ st.st_mode) & S_IFMT) != 0) | |
253 | return -EINVAL; /* insist on the right file type if it was specified */ | |
de321f52 | 254 | |
2dbb7e94 LP |
255 | if (do_chown && do_chmod) { |
256 | mode_t minimal = st.st_mode & mode; /* the subset of the old and the new mask */ | |
30ff18d8 | 257 | |
dee00c19 LP |
258 | if (((minimal ^ st.st_mode) & 07777) != 0) { |
259 | r = fchmod_opath(fd, minimal & 07777); | |
0520564d ZJS |
260 | if (r < 0) { |
261 | if (!path || r != -ENOSYS) | |
262 | return r; | |
263 | ||
264 | /* Fallback path which doesn't use /proc/self/fd/. */ | |
265 | if (chmod(path, minimal & 07777) < 0) | |
266 | return -errno; | |
267 | } | |
dee00c19 | 268 | } |
de321f52 | 269 | } |
b8da477e | 270 | |
2dbb7e94 | 271 | if (do_chown) |
71ec74d1 | 272 | if (fchownat(fd, "", uid, gid, AT_EMPTY_PATH) < 0) |
2dbb7e94 | 273 | return -errno; |
30ff18d8 | 274 | |
dee00c19 LP |
275 | if (do_chmod) { |
276 | r = fchmod_opath(fd, mode & 07777); | |
0520564d ZJS |
277 | if (r < 0) { |
278 | if (!path || r != -ENOSYS) | |
279 | return r; | |
280 | ||
281 | /* Fallback path which doesn't use /proc/self/fd/. */ | |
282 | if (chmod(path, mode & 07777) < 0) | |
283 | return -errno; | |
284 | } | |
dee00c19 | 285 | } |
30ff18d8 | 286 | |
2dbb7e94 | 287 | return do_chown || do_chmod; |
f4f15635 LP |
288 | } |
289 | ||
f4f15635 | 290 | int fchmod_umask(int fd, mode_t m) { |
7c248223 | 291 | _cleanup_umask_ mode_t u = umask(0777); |
f4f15635 | 292 | |
7c248223 | 293 | return RET_NERRNO(fchmod(fd, m & (~u))); |
f4f15635 LP |
294 | } |
295 | ||
4dfaa528 | 296 | int fchmod_opath(int fd, mode_t m) { |
4dfaa528 FB |
297 | /* This function operates also on fd that might have been opened with |
298 | * O_PATH. Indeed fchmodat() doesn't have the AT_EMPTY_PATH flag like | |
299 | * fchownat() does. */ | |
300 | ||
ddb6eeaf | 301 | if (chmod(FORMAT_PROC_FD_PATH(fd), m) < 0) { |
f8606626 LP |
302 | if (errno != ENOENT) |
303 | return -errno; | |
304 | ||
305 | if (proc_mounted() == 0) | |
306 | return -ENOSYS; /* if we have no /proc/, the concept is not implementable */ | |
307 | ||
308 | return -ENOENT; | |
309 | } | |
4dfaa528 FB |
310 | |
311 | return 0; | |
312 | } | |
313 | ||
f25bff5e | 314 | int futimens_opath(int fd, const struct timespec ts[2]) { |
f25bff5e LP |
315 | /* Similar to fchmod_path() but for futimens() */ |
316 | ||
ddb6eeaf | 317 | if (utimensat(AT_FDCWD, FORMAT_PROC_FD_PATH(fd), ts, 0) < 0) { |
f25bff5e LP |
318 | if (errno != ENOENT) |
319 | return -errno; | |
320 | ||
321 | if (proc_mounted() == 0) | |
322 | return -ENOSYS; /* if we have no /proc/, the concept is not implementable */ | |
323 | ||
324 | return -ENOENT; | |
325 | } | |
326 | ||
327 | return 0; | |
328 | } | |
329 | ||
22ed4a6d LP |
330 | int stat_warn_permissions(const char *path, const struct stat *st) { |
331 | assert(path); | |
332 | assert(st); | |
f4f15635 | 333 | |
b6cceaae | 334 | /* Don't complain if we are reading something that is not a file, for example /dev/null */ |
22ed4a6d | 335 | if (!S_ISREG(st->st_mode)) |
b6cceaae LP |
336 | return 0; |
337 | ||
22ed4a6d | 338 | if (st->st_mode & 0111) |
f4f15635 LP |
339 | log_warning("Configuration file %s is marked executable. Please remove executable permission bits. Proceeding anyway.", path); |
340 | ||
22ed4a6d | 341 | if (st->st_mode & 0002) |
f4f15635 LP |
342 | log_warning("Configuration file %s is marked world-writable. Please remove world writability permission bits. Proceeding anyway.", path); |
343 | ||
22ed4a6d | 344 | if (getpid_cached() == 1 && (st->st_mode & 0044) != 0044) |
f4f15635 LP |
345 | 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); |
346 | ||
347 | return 0; | |
348 | } | |
349 | ||
22ed4a6d LP |
350 | int fd_warn_permissions(const char *path, int fd) { |
351 | struct stat st; | |
352 | ||
353 | assert(path); | |
354 | assert(fd >= 0); | |
355 | ||
356 | if (fstat(fd, &st) < 0) | |
357 | return -errno; | |
358 | ||
359 | return stat_warn_permissions(path, &st); | |
360 | } | |
361 | ||
f4f15635 | 362 | int touch_file(const char *path, bool parents, usec_t stamp, uid_t uid, gid_t gid, mode_t mode) { |
254d1313 | 363 | _cleanup_close_ int fd = -EBADF; |
b71dbc6b | 364 | int r, ret; |
f4f15635 LP |
365 | |
366 | assert(path); | |
367 | ||
9e3fa6e8 LP |
368 | /* Note that touch_file() does not follow symlinks: if invoked on an existing symlink, then it is the symlink |
369 | * itself which is updated, not its target | |
370 | * | |
371 | * Returns the first error we encounter, but tries to apply as much as possible. */ | |
f4f15635 | 372 | |
9e3fa6e8 LP |
373 | if (parents) |
374 | (void) mkdir_parents(path, 0755); | |
375 | ||
376 | /* Initially, we try to open the node with O_PATH, so that we get a reference to the node. This is useful in | |
377 | * case the path refers to an existing device or socket node, as we can open it successfully in all cases, and | |
378 | * won't trigger any driver magic or so. */ | |
379 | fd = open(path, O_PATH|O_CLOEXEC|O_NOFOLLOW); | |
380 | if (fd < 0) { | |
381 | if (errno != ENOENT) | |
f4f15635 | 382 | return -errno; |
f4f15635 | 383 | |
9e3fa6e8 LP |
384 | /* if the node doesn't exist yet, we create it, but with O_EXCL, so that we only create a regular file |
385 | * here, and nothing else */ | |
386 | fd = open(path, O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC, IN_SET(mode, 0, MODE_INVALID) ? 0644 : mode); | |
387 | if (fd < 0) | |
f4f15635 LP |
388 | return -errno; |
389 | } | |
390 | ||
9e3fa6e8 LP |
391 | /* Let's make a path from the fd, and operate on that. With this logic, we can adjust the access mode, |
392 | * ownership and time of the file node in all cases, even if the fd refers to an O_PATH object — which is | |
393 | * something fchown(), fchmod(), futimensat() don't allow. */ | |
4b3b5bc7 | 394 | ret = fchmod_and_chown(fd, mode, uid, gid); |
9e3fa6e8 | 395 | |
f4f15635 LP |
396 | if (stamp != USEC_INFINITY) { |
397 | struct timespec ts[2]; | |
398 | ||
399 | timespec_store(&ts[0], stamp); | |
400 | ts[1] = ts[0]; | |
b5794711 | 401 | r = futimens_opath(fd, ts); |
f4f15635 | 402 | } else |
b5794711 | 403 | r = futimens_opath(fd, NULL); |
9e3fa6e8 | 404 | if (r < 0 && ret >= 0) |
b5794711 | 405 | return r; |
f4f15635 | 406 | |
9e3fa6e8 | 407 | return ret; |
f4f15635 LP |
408 | } |
409 | ||
6c9c51e5 YW |
410 | int symlink_idempotent(const char *from, const char *to, bool make_relative) { |
411 | _cleanup_free_ char *relpath = NULL; | |
f4f15635 LP |
412 | int r; |
413 | ||
414 | assert(from); | |
415 | assert(to); | |
416 | ||
6c9c51e5 | 417 | if (make_relative) { |
449375d2 | 418 | r = path_make_relative_parent(to, from, &relpath); |
6c9c51e5 YW |
419 | if (r < 0) |
420 | return r; | |
421 | ||
422 | from = relpath; | |
423 | } | |
424 | ||
f4f15635 | 425 | if (symlink(from, to) < 0) { |
77b79723 LP |
426 | _cleanup_free_ char *p = NULL; |
427 | ||
f4f15635 LP |
428 | if (errno != EEXIST) |
429 | return -errno; | |
430 | ||
431 | r = readlink_malloc(to, &p); | |
77b79723 LP |
432 | if (r == -EINVAL) /* Not a symlink? In that case return the original error we encountered: -EEXIST */ |
433 | return -EEXIST; | |
434 | if (r < 0) /* Any other error? In that case propagate it as is */ | |
f4f15635 LP |
435 | return r; |
436 | ||
77b79723 LP |
437 | if (!streq(p, from)) /* Not the symlink we want it to be? In that case, propagate the original -EEXIST */ |
438 | return -EEXIST; | |
f4f15635 LP |
439 | } |
440 | ||
441 | return 0; | |
442 | } | |
443 | ||
da9dd029 | 444 | int symlinkat_atomic_full(const char *from, int atfd, const char *to, bool make_relative) { |
590d8100 | 445 | _cleanup_free_ char *relpath = NULL, *t = NULL; |
f4f15635 LP |
446 | int r; |
447 | ||
448 | assert(from); | |
449 | assert(to); | |
450 | ||
590d8100 YW |
451 | if (make_relative) { |
452 | r = path_make_relative_parent(to, from, &relpath); | |
453 | if (r < 0) | |
454 | return r; | |
455 | ||
456 | from = relpath; | |
457 | } | |
458 | ||
f4f15635 LP |
459 | r = tempfn_random(to, NULL, &t); |
460 | if (r < 0) | |
461 | return r; | |
462 | ||
da9dd029 | 463 | if (symlinkat(from, atfd, t) < 0) |
f4f15635 LP |
464 | return -errno; |
465 | ||
da9dd029 LP |
466 | r = RET_NERRNO(renameat(atfd, t, atfd, to)); |
467 | if (r < 0) { | |
468 | (void) unlinkat(atfd, t, 0); | |
469 | return r; | |
f4f15635 LP |
470 | } |
471 | ||
472 | return 0; | |
473 | } | |
474 | ||
497ca785 | 475 | int mknodat_atomic(int atfd, const char *path, mode_t mode, dev_t dev) { |
f4f15635 LP |
476 | _cleanup_free_ char *t = NULL; |
477 | int r; | |
478 | ||
479 | assert(path); | |
480 | ||
481 | r = tempfn_random(path, NULL, &t); | |
482 | if (r < 0) | |
483 | return r; | |
484 | ||
497ca785 | 485 | if (mknodat(atfd, t, mode, dev) < 0) |
f4f15635 LP |
486 | return -errno; |
487 | ||
497ca785 LP |
488 | r = RET_NERRNO(renameat(atfd, t, atfd, path)); |
489 | if (r < 0) { | |
490 | (void) unlinkat(atfd, t, 0); | |
491 | return r; | |
f4f15635 LP |
492 | } |
493 | ||
494 | return 0; | |
495 | } | |
496 | ||
4f477796 | 497 | int mkfifoat_atomic(int atfd, const char *path, mode_t mode) { |
f4f15635 LP |
498 | _cleanup_free_ char *t = NULL; |
499 | int r; | |
500 | ||
501 | assert(path); | |
502 | ||
4f477796 | 503 | /* We're only interested in the (random) filename. */ |
f4f15635 LP |
504 | r = tempfn_random(path, NULL, &t); |
505 | if (r < 0) | |
506 | return r; | |
507 | ||
4f477796 | 508 | if (mkfifoat(atfd, t, mode) < 0) |
4fe3828c | 509 | return -errno; |
4fe3828c | 510 | |
4f477796 LP |
511 | r = RET_NERRNO(renameat(atfd, t, atfd, path)); |
512 | if (r < 0) { | |
513 | (void) unlinkat(atfd, t, 0); | |
4fe3828c | 514 | return r; |
f4f15635 LP |
515 | } |
516 | ||
517 | return 0; | |
518 | } | |
519 | ||
520 | int get_files_in_directory(const char *path, char ***list) { | |
319a4f4b | 521 | _cleanup_strv_free_ char **l = NULL; |
f4f15635 | 522 | _cleanup_closedir_ DIR *d = NULL; |
319a4f4b | 523 | size_t n = 0; |
f4f15635 LP |
524 | |
525 | assert(path); | |
526 | ||
527 | /* Returns all files in a directory in *list, and the number | |
528 | * of files as return value. If list is NULL returns only the | |
529 | * number. */ | |
530 | ||
531 | d = opendir(path); | |
532 | if (!d) | |
533 | return -errno; | |
534 | ||
8fb3f009 | 535 | FOREACH_DIRENT_ALL(de, d, return -errno) { |
f4f15635 LP |
536 | if (!dirent_is_file(de)) |
537 | continue; | |
538 | ||
539 | if (list) { | |
540 | /* one extra slot is needed for the terminating NULL */ | |
319a4f4b | 541 | if (!GREEDY_REALLOC(l, n + 2)) |
f4f15635 LP |
542 | return -ENOMEM; |
543 | ||
544 | l[n] = strdup(de->d_name); | |
545 | if (!l[n]) | |
546 | return -ENOMEM; | |
547 | ||
548 | l[++n] = NULL; | |
549 | } else | |
550 | n++; | |
551 | } | |
552 | ||
ae2a15bc LP |
553 | if (list) |
554 | *list = TAKE_PTR(l); | |
f4f15635 LP |
555 | |
556 | return n; | |
557 | } | |
430fbf8e | 558 | |
992e8f22 | 559 | static int getenv_tmp_dir(const char **ret_path) { |
992e8f22 | 560 | int r, ret = 0; |
34a8f081 | 561 | |
992e8f22 | 562 | assert(ret_path); |
34a8f081 | 563 | |
992e8f22 LP |
564 | /* We use the same order of environment variables python uses in tempfile.gettempdir(): |
565 | * https://docs.python.org/3/library/tempfile.html#tempfile.gettempdir */ | |
566 | FOREACH_STRING(n, "TMPDIR", "TEMP", "TMP") { | |
567 | const char *e; | |
568 | ||
569 | e = secure_getenv(n); | |
570 | if (!e) | |
571 | continue; | |
572 | if (!path_is_absolute(e)) { | |
573 | r = -ENOTDIR; | |
574 | goto next; | |
575 | } | |
99be45a4 | 576 | if (!path_is_normalized(e)) { |
992e8f22 LP |
577 | r = -EPERM; |
578 | goto next; | |
579 | } | |
580 | ||
581 | r = is_dir(e, true); | |
582 | if (r < 0) | |
583 | goto next; | |
584 | if (r == 0) { | |
585 | r = -ENOTDIR; | |
586 | goto next; | |
587 | } | |
588 | ||
589 | *ret_path = e; | |
590 | return 1; | |
591 | ||
592 | next: | |
593 | /* Remember first error, to make this more debuggable */ | |
594 | if (ret >= 0) | |
595 | ret = r; | |
34a8f081 OW |
596 | } |
597 | ||
992e8f22 LP |
598 | if (ret < 0) |
599 | return ret; | |
34a8f081 | 600 | |
992e8f22 LP |
601 | *ret_path = NULL; |
602 | return ret; | |
603 | } | |
34a8f081 | 604 | |
992e8f22 LP |
605 | static int tmp_dir_internal(const char *def, const char **ret) { |
606 | const char *e; | |
607 | int r, k; | |
608 | ||
609 | assert(def); | |
610 | assert(ret); | |
611 | ||
612 | r = getenv_tmp_dir(&e); | |
613 | if (r > 0) { | |
614 | *ret = e; | |
615 | return 0; | |
616 | } | |
617 | ||
618 | k = is_dir(def, true); | |
619 | if (k == 0) | |
620 | k = -ENOTDIR; | |
621 | if (k < 0) | |
622 | return r < 0 ? r : k; | |
623 | ||
624 | *ret = def; | |
34a8f081 OW |
625 | return 0; |
626 | } | |
627 | ||
992e8f22 LP |
628 | int var_tmp_dir(const char **ret) { |
629 | ||
630 | /* Returns the location for "larger" temporary files, that is backed by physical storage if available, and thus | |
631 | * even might survive a boot: /var/tmp. If $TMPDIR (or related environment variables) are set, its value is | |
632 | * returned preferably however. Note that both this function and tmp_dir() below are affected by $TMPDIR, | |
633 | * making it a variable that overrides all temporary file storage locations. */ | |
634 | ||
635 | return tmp_dir_internal("/var/tmp", ret); | |
636 | } | |
637 | ||
638 | int tmp_dir(const char **ret) { | |
639 | ||
640 | /* Similar to var_tmp_dir() above, but returns the location for "smaller" temporary files, which is usually | |
641 | * backed by an in-memory file system: /tmp. */ | |
642 | ||
643 | return tmp_dir_internal("/tmp", ret); | |
644 | } | |
645 | ||
af229d7a ZJS |
646 | int unlink_or_warn(const char *filename) { |
647 | if (unlink(filename) < 0 && errno != ENOENT) | |
648 | /* If the file doesn't exist and the fs simply was read-only (in which | |
649 | * case unlink() returns EROFS even if the file doesn't exist), don't | |
650 | * complain */ | |
651 | if (errno != EROFS || access(filename, F_OK) >= 0) | |
652 | return log_error_errno(errno, "Failed to remove \"%s\": %m", filename); | |
653 | ||
654 | return 0; | |
655 | } | |
656 | ||
57a4359e | 657 | int access_fd(int fd, int mode) { |
57a4359e LP |
658 | /* Like access() but operates on an already open fd */ |
659 | ||
ddb6eeaf | 660 | if (access(FORMAT_PROC_FD_PATH(fd), mode) < 0) { |
4265a66a LP |
661 | if (errno != ENOENT) |
662 | return -errno; | |
57a4359e | 663 | |
4265a66a LP |
664 | /* ENOENT can mean two things: that the fd does not exist or that /proc is not mounted. Let's |
665 | * make things debuggable and distinguish the two. */ | |
666 | ||
667 | if (proc_mounted() == 0) | |
668 | return -ENOSYS; /* /proc is not available or not set up properly, we're most likely in some chroot | |
669 | * environment. */ | |
670 | ||
671 | return -EBADF; /* The directory exists, hence it's the fd that doesn't. */ | |
672 | } | |
673 | ||
674 | return 0; | |
57a4359e | 675 | } |
43767d9d | 676 | |
627d2bac ZJS |
677 | void unlink_tempfilep(char (*p)[]) { |
678 | /* If the file is created with mkstemp(), it will (almost always) | |
679 | * change the suffix. Treat this as a sign that the file was | |
680 | * successfully created. We ignore both the rare case where the | |
681 | * original suffix is used and unlink failures. */ | |
682 | if (!endswith(*p, ".XXXXXX")) | |
69821560 | 683 | (void) unlink_noerrno(*p); |
627d2bac ZJS |
684 | } |
685 | ||
053e0626 | 686 | int unlinkat_deallocate(int fd, const char *name, UnlinkDeallocateFlags flags) { |
254d1313 | 687 | _cleanup_close_ int truncate_fd = -EBADF; |
43767d9d LP |
688 | struct stat st; |
689 | off_t l, bs; | |
690 | ||
053e0626 LP |
691 | assert((flags & ~(UNLINK_REMOVEDIR|UNLINK_ERASE)) == 0); |
692 | ||
43767d9d LP |
693 | /* Operates like unlinkat() but also deallocates the file contents if it is a regular file and there's no other |
694 | * link to it. This is useful to ensure that other processes that might have the file open for reading won't be | |
695 | * able to keep the data pinned on disk forever. This call is particular useful whenever we execute clean-up | |
696 | * jobs ("vacuuming"), where we want to make sure the data is really gone and the disk space released and | |
697 | * returned to the free pool. | |
698 | * | |
699 | * Deallocation is preferably done by FALLOC_FL_PUNCH_HOLE|FALLOC_FL_KEEP_SIZE (👊) if supported, which means | |
700 | * the file won't change size. That's a good thing since we shouldn't needlessly trigger SIGBUS in other | |
701 | * programs that have mmap()ed the file. (The assumption here is that changing file contents to all zeroes | |
702 | * underneath those programs is the better choice than simply triggering SIGBUS in them which truncation does.) | |
703 | * However if hole punching is not implemented in the kernel or file system we'll fall back to normal file | |
704 | * truncation (🔪), as our goal of deallocating the data space trumps our goal of being nice to readers (💐). | |
705 | * | |
706 | * Note that we attempt deallocation, but failure to succeed with that is not considered fatal, as long as the | |
707 | * primary job – to delete the file – is accomplished. */ | |
708 | ||
053e0626 | 709 | if (!FLAGS_SET(flags, UNLINK_REMOVEDIR)) { |
43767d9d LP |
710 | truncate_fd = openat(fd, name, O_WRONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW|O_NONBLOCK); |
711 | if (truncate_fd < 0) { | |
712 | ||
713 | /* If this failed because the file doesn't exist propagate the error right-away. Also, | |
714 | * AT_REMOVEDIR wasn't set, and we tried to open the file for writing, which means EISDIR is | |
715 | * returned when this is a directory but we are not supposed to delete those, hence propagate | |
716 | * the error right-away too. */ | |
717 | if (IN_SET(errno, ENOENT, EISDIR)) | |
718 | return -errno; | |
719 | ||
720 | if (errno != ELOOP) /* don't complain if this is a symlink */ | |
721 | log_debug_errno(errno, "Failed to open file '%s' for deallocation, ignoring: %m", name); | |
722 | } | |
723 | } | |
724 | ||
053e0626 | 725 | if (unlinkat(fd, name, FLAGS_SET(flags, UNLINK_REMOVEDIR) ? AT_REMOVEDIR : 0) < 0) |
43767d9d LP |
726 | return -errno; |
727 | ||
728 | if (truncate_fd < 0) /* Don't have a file handle, can't do more ☹️ */ | |
729 | return 0; | |
730 | ||
731 | if (fstat(truncate_fd, &st) < 0) { | |
011723a4 | 732 | log_debug_errno(errno, "Failed to stat file '%s' for deallocation, ignoring: %m", name); |
43767d9d LP |
733 | return 0; |
734 | } | |
735 | ||
053e0626 LP |
736 | if (!S_ISREG(st.st_mode)) |
737 | return 0; | |
738 | ||
739 | if (FLAGS_SET(flags, UNLINK_ERASE) && st.st_size > 0 && st.st_nlink == 0) { | |
740 | uint64_t left = st.st_size; | |
741 | char buffer[64 * 1024]; | |
742 | ||
743 | /* If erasing is requested, let's overwrite the file with random data once before deleting | |
744 | * it. This isn't going to give you shred(1) semantics, but hopefully should be good enough | |
745 | * for stuff backed by tmpfs at least. | |
746 | * | |
15dd4515 | 747 | * Note that we only erase like this if the link count of the file is zero. If it is higher it |
053e0626 LP |
748 | * is still linked by someone else and we'll leave it to them to remove it securely |
749 | * eventually! */ | |
750 | ||
751 | random_bytes(buffer, sizeof(buffer)); | |
752 | ||
753 | while (left > 0) { | |
754 | ssize_t n; | |
755 | ||
756 | n = write(truncate_fd, buffer, MIN(sizeof(buffer), left)); | |
757 | if (n < 0) { | |
758 | log_debug_errno(errno, "Failed to erase data in file '%s', ignoring.", name); | |
759 | break; | |
760 | } | |
761 | ||
762 | assert(left >= (size_t) n); | |
763 | left -= n; | |
764 | } | |
765 | ||
766 | /* Let's refresh metadata */ | |
767 | if (fstat(truncate_fd, &st) < 0) { | |
768 | log_debug_errno(errno, "Failed to stat file '%s' for deallocation, ignoring: %m", name); | |
769 | return 0; | |
770 | } | |
771 | } | |
772 | ||
773 | /* Don't dallocate if there's nothing to deallocate or if the file is linked elsewhere */ | |
774 | if (st.st_blocks == 0 || st.st_nlink > 0) | |
43767d9d LP |
775 | return 0; |
776 | ||
777 | /* If this is a regular file, it actually took up space on disk and there are no other links it's time to | |
778 | * punch-hole/truncate this to release the disk space. */ | |
779 | ||
780 | bs = MAX(st.st_blksize, 512); | |
781 | l = DIV_ROUND_UP(st.st_size, bs) * bs; /* Round up to next block size */ | |
782 | ||
783 | if (fallocate(truncate_fd, FALLOC_FL_PUNCH_HOLE|FALLOC_FL_KEEP_SIZE, 0, l) >= 0) | |
784 | return 0; /* Successfully punched a hole! 😊 */ | |
785 | ||
786 | /* Fall back to truncation */ | |
787 | if (ftruncate(truncate_fd, 0) < 0) { | |
788 | log_debug_errno(errno, "Failed to truncate file to 0, ignoring: %m"); | |
789 | return 0; | |
790 | } | |
791 | ||
792 | return 0; | |
793 | } | |
11b29a96 | 794 | |
ef8becfa LP |
795 | int open_parent(const char *path, int flags, mode_t mode) { |
796 | _cleanup_free_ char *parent = NULL; | |
7c248223 | 797 | int r; |
ef8becfa | 798 | |
30cdcd62 LP |
799 | r = path_extract_directory(path, &parent); |
800 | if (r < 0) | |
801 | return r; | |
ef8becfa LP |
802 | |
803 | /* Let's insist on O_DIRECTORY since the parent of a file or directory is a directory. Except if we open an | |
804 | * O_TMPFILE file, because in that case we are actually create a regular file below the parent directory. */ | |
805 | ||
0c21dafb | 806 | if (FLAGS_SET(flags, O_PATH)) |
ef8becfa | 807 | flags |= O_DIRECTORY; |
0c21dafb | 808 | else if (!FLAGS_SET(flags, O_TMPFILE)) |
ef8becfa LP |
809 | flags |= O_DIRECTORY|O_RDONLY; |
810 | ||
7c248223 | 811 | return RET_NERRNO(open(parent, flags, mode)); |
ef8becfa | 812 | } |
ed9c0851 | 813 | |
10195179 | 814 | int conservative_renameat( |
10981424 LP |
815 | int olddirfd, const char *oldpath, |
816 | int newdirfd, const char *newpath) { | |
817 | ||
254d1313 | 818 | _cleanup_close_ int old_fd = -EBADF, new_fd = -EBADF; |
10981424 LP |
819 | struct stat old_stat, new_stat; |
820 | ||
821 | /* Renames the old path to thew new path, much like renameat() — except if both are regular files and | |
822 | * have the exact same contents and basic file attributes already. In that case remove the new file | |
823 | * instead. This call is useful for reducing inotify wakeups on files that are updated but don't | |
824 | * actually change. This function is written in a style that we rather rename too often than suppress | |
825 | * too much. i.e. whenever we are in doubt we rather rename than fail. After all reducing inotify | |
826 | * events is an optimization only, not more. */ | |
827 | ||
828 | old_fd = openat(olddirfd, oldpath, O_CLOEXEC|O_RDONLY|O_NOCTTY|O_NOFOLLOW); | |
829 | if (old_fd < 0) | |
830 | goto do_rename; | |
831 | ||
832 | new_fd = openat(newdirfd, newpath, O_CLOEXEC|O_RDONLY|O_NOCTTY|O_NOFOLLOW); | |
833 | if (new_fd < 0) | |
834 | goto do_rename; | |
835 | ||
836 | if (fstat(old_fd, &old_stat) < 0) | |
837 | goto do_rename; | |
838 | ||
839 | if (!S_ISREG(old_stat.st_mode)) | |
840 | goto do_rename; | |
841 | ||
842 | if (fstat(new_fd, &new_stat) < 0) | |
843 | goto do_rename; | |
844 | ||
a9dac7a6 | 845 | if (stat_inode_same(&new_stat, &old_stat)) |
10981424 LP |
846 | goto is_same; |
847 | ||
848 | if (old_stat.st_mode != new_stat.st_mode || | |
849 | old_stat.st_size != new_stat.st_size || | |
850 | old_stat.st_uid != new_stat.st_uid || | |
851 | old_stat.st_gid != new_stat.st_gid) | |
852 | goto do_rename; | |
853 | ||
854 | for (;;) { | |
eff57d1c LP |
855 | uint8_t buf1[16*1024]; |
856 | uint8_t buf2[sizeof(buf1)]; | |
10981424 LP |
857 | ssize_t l1, l2; |
858 | ||
859 | l1 = read(old_fd, buf1, sizeof(buf1)); | |
860 | if (l1 < 0) | |
861 | goto do_rename; | |
862 | ||
eff57d1c LP |
863 | if (l1 == sizeof(buf1)) |
864 | /* Read the full block, hence read a full block in the other file too */ | |
10981424 | 865 | |
eff57d1c LP |
866 | l2 = read(new_fd, buf2, l1); |
867 | else { | |
868 | assert((size_t) l1 < sizeof(buf1)); | |
869 | ||
870 | /* Short read. This hence was the last block in the first file, and then came | |
871 | * EOF. Read one byte more in the second file, so that we can verify we hit EOF there | |
872 | * too. */ | |
873 | ||
874 | assert((size_t) (l1 + 1) <= sizeof(buf2)); | |
875 | l2 = read(new_fd, buf2, l1 + 1); | |
876 | } | |
877 | if (l2 != l1) | |
878 | goto do_rename; | |
10981424 LP |
879 | |
880 | if (memcmp(buf1, buf2, l1) != 0) | |
881 | goto do_rename; | |
eff57d1c LP |
882 | |
883 | if ((size_t) l1 < sizeof(buf1)) /* We hit EOF on the first file, and the second file too, hence exit | |
884 | * now. */ | |
885 | break; | |
10981424 LP |
886 | } |
887 | ||
888 | is_same: | |
889 | /* Everything matches? Then don't rename, instead remove the source file, and leave the existing | |
890 | * destination in place */ | |
891 | ||
892 | if (unlinkat(olddirfd, oldpath, 0) < 0) | |
893 | goto do_rename; | |
894 | ||
895 | return 0; | |
896 | ||
897 | do_rename: | |
898 | if (renameat(olddirfd, oldpath, newdirfd, newpath) < 0) | |
899 | return -errno; | |
900 | ||
901 | return 1; | |
902 | } | |
4c54768c IZ |
903 | |
904 | int posix_fallocate_loop(int fd, uint64_t offset, uint64_t size) { | |
905 | RateLimit rl; | |
906 | int r; | |
907 | ||
908 | r = posix_fallocate(fd, offset, size); /* returns positive errnos on error */ | |
909 | if (r != EINTR) | |
910 | return -r; /* Let's return negative errnos, like common in our codebase */ | |
911 | ||
912 | /* On EINTR try a couple of times more, but protect against busy looping | |
913 | * (not more than 16 times per 10s) */ | |
7d1e61ca | 914 | rl = (const RateLimit) { 10 * USEC_PER_SEC, 16 }; |
4c54768c IZ |
915 | while (ratelimit_below(&rl)) { |
916 | r = posix_fallocate(fd, offset, size); | |
917 | if (r != EINTR) | |
918 | return -r; | |
919 | } | |
920 | ||
921 | return -EINTR; | |
922 | } | |
68def5a9 LP |
923 | |
924 | int parse_cifs_service( | |
925 | const char *s, | |
926 | char **ret_host, | |
927 | char **ret_service, | |
928 | char **ret_path) { | |
929 | ||
930 | _cleanup_free_ char *h = NULL, *ss = NULL, *x = NULL; | |
931 | const char *p, *e, *d; | |
932 | char delimiter; | |
933 | ||
934 | /* Parses a CIFS service in form of //host/service/path… and splitting it in three parts. The last | |
935 | * part is optional, in which case NULL is returned there. To maximize compatibility syntax with | |
936 | * backslashes instead of slashes is accepted too. */ | |
937 | ||
938 | if (!s) | |
939 | return -EINVAL; | |
940 | ||
941 | p = startswith(s, "//"); | |
942 | if (!p) { | |
943 | p = startswith(s, "\\\\"); | |
944 | if (!p) | |
945 | return -EINVAL; | |
946 | } | |
947 | ||
948 | delimiter = s[0]; | |
949 | e = strchr(p, delimiter); | |
950 | if (!e) | |
951 | return -EINVAL; | |
952 | ||
953 | h = strndup(p, e - p); | |
954 | if (!h) | |
955 | return -ENOMEM; | |
956 | ||
957 | if (!hostname_is_valid(h, 0)) | |
958 | return -EINVAL; | |
959 | ||
960 | e++; | |
961 | ||
962 | d = strchrnul(e, delimiter); | |
963 | ||
964 | ss = strndup(e, d - e); | |
965 | if (!ss) | |
966 | return -ENOMEM; | |
967 | ||
968 | if (!filename_is_valid(ss)) | |
969 | return -EINVAL; | |
970 | ||
971 | if (!isempty(d)) { | |
972 | x = strdup(skip_leading_chars(d, CHAR_TO_STR(delimiter))); | |
973 | if (!x) | |
974 | return -EINVAL; | |
975 | ||
976 | /* Make sure to convert Windows-style "\" → Unix-style / */ | |
977 | for (char *i = x; *i; i++) | |
978 | if (*i == delimiter) | |
979 | *i = '/'; | |
980 | ||
981 | if (!path_is_valid(x)) | |
982 | return -EINVAL; | |
983 | ||
984 | path_simplify(x); | |
985 | if (!path_is_normalized(x)) | |
986 | return -EINVAL; | |
987 | } | |
988 | ||
989 | if (ret_host) | |
990 | *ret_host = TAKE_PTR(h); | |
991 | if (ret_service) | |
992 | *ret_service = TAKE_PTR(ss); | |
993 | if (ret_path) | |
994 | *ret_path = TAKE_PTR(x); | |
995 | ||
996 | return 0; | |
997 | } | |
c73094f3 LP |
998 | |
999 | int open_mkdir_at(int dirfd, const char *path, int flags, mode_t mode) { | |
254d1313 | 1000 | _cleanup_close_ int fd = -EBADF, parent_fd = -EBADF; |
c73094f3 LP |
1001 | _cleanup_free_ char *fname = NULL; |
1002 | bool made; | |
1003 | int r; | |
1004 | ||
1005 | /* Creates a directory with mkdirat() and then opens it, in the "most atomic" fashion we can | |
1006 | * do. Guarantees that the returned fd refers to a directory. If O_EXCL is specified will fail if the | |
1007 | * dir already exists. Otherwise will open an existing dir, but only if it is one. */ | |
1008 | ||
1009 | if (flags & ~(O_RDONLY|O_CLOEXEC|O_DIRECTORY|O_EXCL|O_NOATIME|O_NOFOLLOW|O_PATH)) | |
1010 | return -EINVAL; | |
1011 | if ((flags & O_ACCMODE) != O_RDONLY) | |
1012 | return -EINVAL; | |
1013 | ||
1014 | /* Note that O_DIRECTORY|O_NOFOLLOW is implied, but we allow specifying it anyway. The following | |
1015 | * flags actually make sense to specify: O_CLOEXEC, O_EXCL, O_NOATIME, O_PATH */ | |
1016 | ||
1017 | if (isempty(path)) | |
1018 | return -EINVAL; | |
1019 | ||
1020 | if (!filename_is_valid(path)) { | |
1021 | _cleanup_free_ char *parent = NULL; | |
1022 | ||
1023 | /* If this is not a valid filename, it's a path. Let's open the parent directory then, so | |
1024 | * that we can pin it, and operate below it. */ | |
1025 | ||
1026 | r = path_extract_directory(path, &parent); | |
1027 | if (r < 0) | |
1028 | return r; | |
1029 | ||
1030 | r = path_extract_filename(path, &fname); | |
1031 | if (r < 0) | |
1032 | return r; | |
1033 | ||
1034 | parent_fd = openat(dirfd, parent, O_PATH|O_DIRECTORY|O_CLOEXEC); | |
1035 | if (parent_fd < 0) | |
1036 | return -errno; | |
1037 | ||
1038 | dirfd = parent_fd; | |
1039 | path = fname; | |
1040 | } | |
1041 | ||
1042 | r = RET_NERRNO(mkdirat(dirfd, path, mode)); | |
1043 | if (r == -EEXIST) { | |
1044 | if (FLAGS_SET(flags, O_EXCL)) | |
1045 | return -EEXIST; | |
1046 | ||
1047 | made = false; | |
1048 | } else if (r < 0) | |
1049 | return r; | |
1050 | else | |
1051 | made = true; | |
1052 | ||
1053 | fd = RET_NERRNO(openat(dirfd, path, (flags & ~O_EXCL)|O_DIRECTORY|O_NOFOLLOW)); | |
1054 | if (fd < 0) { | |
1055 | if (fd == -ENOENT) /* We got ENOENT? then someone else immediately removed it after we | |
1056 | * created it. In that case let's return immediately without unlinking | |
1057 | * anything, because there simply isn't anything to unlink anymore. */ | |
1058 | return -ENOENT; | |
1059 | if (fd == -ELOOP) /* is a symlink? exists already → created by someone else, don't unlink */ | |
1060 | return -EEXIST; | |
1061 | if (fd == -ENOTDIR) /* not a directory? exists already → created by someone else, don't unlink */ | |
1062 | return -EEXIST; | |
1063 | ||
1064 | if (made) | |
1065 | (void) unlinkat(dirfd, path, AT_REMOVEDIR); | |
1066 | ||
1067 | return fd; | |
1068 | } | |
1069 | ||
1070 | return TAKE_FD(fd); | |
1071 | } | |
ca8503f1 LP |
1072 | |
1073 | int openat_report_new(int dirfd, const char *pathname, int flags, mode_t mode, bool *ret_newly_created) { | |
1074 | unsigned attempts = 7; | |
4d5dacbe | 1075 | int fd; |
ca8503f1 LP |
1076 | |
1077 | /* Just like openat(), but adds one thing: optionally returns whether we created the file anew or if | |
b3122369 | 1078 | * it already existed before. This is only relevant if O_CREAT is set without O_EXCL, and thus will |
ca8503f1 LP |
1079 | * shortcut to openat() otherwise */ |
1080 | ||
4d5dacbe | 1081 | if (!ret_newly_created) |
ca8503f1 LP |
1082 | return RET_NERRNO(openat(dirfd, pathname, flags, mode)); |
1083 | ||
4d5dacbe LP |
1084 | if (!FLAGS_SET(flags, O_CREAT) || FLAGS_SET(flags, O_EXCL)) { |
1085 | fd = openat(dirfd, pathname, flags, mode); | |
1086 | if (fd < 0) | |
1087 | return -errno; | |
ca8503f1 | 1088 | |
4d5dacbe LP |
1089 | *ret_newly_created = FLAGS_SET(flags, O_CREAT); |
1090 | return fd; | |
1091 | } | |
1092 | ||
1093 | for (;;) { | |
ca8503f1 LP |
1094 | /* First, attempt to open without O_CREAT/O_EXCL, i.e. open existing file */ |
1095 | fd = openat(dirfd, pathname, flags & ~(O_CREAT | O_EXCL), mode); | |
1096 | if (fd >= 0) { | |
1097 | *ret_newly_created = false; | |
1098 | return fd; | |
1099 | } | |
1100 | if (errno != ENOENT) | |
1101 | return -errno; | |
1102 | ||
1103 | /* So the file didn't exist yet, hence create it with O_CREAT/O_EXCL. */ | |
1104 | fd = openat(dirfd, pathname, flags | O_CREAT | O_EXCL, mode); | |
1105 | if (fd >= 0) { | |
1106 | *ret_newly_created = true; | |
1107 | return fd; | |
1108 | } | |
1109 | if (errno != EEXIST) | |
1110 | return -errno; | |
1111 | ||
1112 | /* Hmm, so now we got EEXIST? So it apparently exists now? If so, let's try to open again | |
b3122369 | 1113 | * without the two flags. But let's not spin forever, hence put a limit on things */ |
ca8503f1 LP |
1114 | |
1115 | if (--attempts == 0) /* Give up eventually, somebody is playing with us */ | |
1116 | return -EEXIST; | |
1117 | } | |
1118 | } |