]>
Commit | Line | Data |
---|---|---|
1 | /* SPDX-License-Identifier: LGPL-2.1+ */ | |
2 | /*** | |
3 | This file is part of systemd. | |
4 | ||
5 | Copyright 2010 ProFUSION embedded systems | |
6 | ||
7 | systemd is free software; you can redistribute it and/or modify it | |
8 | under the terms of the GNU Lesser General Public License as published by | |
9 | the Free Software Foundation; either version 2.1 of the License, or | |
10 | (at your option) any later version. | |
11 | ||
12 | systemd is distributed in the hope that it will be useful, but | |
13 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
15 | Lesser General Public License for more details. | |
16 | ||
17 | You should have received a copy of the GNU Lesser General Public License | |
18 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
19 | ***/ | |
20 | ||
21 | #include <errno.h> | |
22 | #include <fcntl.h> | |
23 | #include <linux/loop.h> | |
24 | #include <string.h> | |
25 | #include <sys/mount.h> | |
26 | #include <sys/swap.h> | |
27 | ||
28 | #include "libudev.h" | |
29 | ||
30 | #include "alloc-util.h" | |
31 | #include "escape.h" | |
32 | #include "fd-util.h" | |
33 | #include "fstab-util.h" | |
34 | #include "linux-3.13/dm-ioctl.h" | |
35 | #include "list.h" | |
36 | #include "mount-setup.h" | |
37 | #include "path-util.h" | |
38 | #include "string-util.h" | |
39 | #include "udev-util.h" | |
40 | #include "umount.h" | |
41 | #include "mount-util.h" | |
42 | #include "util.h" | |
43 | #include "virt.h" | |
44 | ||
45 | typedef struct MountPoint { | |
46 | char *path; | |
47 | char *options; | |
48 | char *type; | |
49 | dev_t devnum; | |
50 | LIST_FIELDS(struct MountPoint, mount_point); | |
51 | } MountPoint; | |
52 | ||
53 | static void mount_point_free(MountPoint **head, MountPoint *m) { | |
54 | assert(head); | |
55 | assert(m); | |
56 | ||
57 | LIST_REMOVE(mount_point, *head, m); | |
58 | ||
59 | free(m->path); | |
60 | free(m); | |
61 | } | |
62 | ||
63 | static void mount_points_list_free(MountPoint **head) { | |
64 | assert(head); | |
65 | ||
66 | while (*head) | |
67 | mount_point_free(head, *head); | |
68 | } | |
69 | ||
70 | static int mount_points_list_get(MountPoint **head) { | |
71 | _cleanup_fclose_ FILE *proc_self_mountinfo = NULL; | |
72 | unsigned int i; | |
73 | int r; | |
74 | ||
75 | assert(head); | |
76 | ||
77 | proc_self_mountinfo = fopen("/proc/self/mountinfo", "re"); | |
78 | if (!proc_self_mountinfo) | |
79 | return -errno; | |
80 | ||
81 | for (i = 1;; i++) { | |
82 | _cleanup_free_ char *path = NULL, *options = NULL, *type = NULL; | |
83 | char *p = NULL; | |
84 | MountPoint *m; | |
85 | int k; | |
86 | ||
87 | k = fscanf(proc_self_mountinfo, | |
88 | "%*s " /* (1) mount id */ | |
89 | "%*s " /* (2) parent id */ | |
90 | "%*s " /* (3) major:minor */ | |
91 | "%*s " /* (4) root */ | |
92 | "%ms " /* (5) mount point */ | |
93 | "%*s" /* (6) mount flags */ | |
94 | "%*[^-]" /* (7) optional fields */ | |
95 | "- " /* (8) separator */ | |
96 | "%ms " /* (9) file system type */ | |
97 | "%*s" /* (10) mount source */ | |
98 | "%ms" /* (11) mount options */ | |
99 | "%*[^\n]", /* some rubbish at the end */ | |
100 | &path, &type, &options); | |
101 | if (k != 3) { | |
102 | if (k == EOF) | |
103 | break; | |
104 | ||
105 | log_warning("Failed to parse /proc/self/mountinfo:%u.", i); | |
106 | continue; | |
107 | } | |
108 | ||
109 | r = cunescape(path, UNESCAPE_RELAX, &p); | |
110 | if (r < 0) | |
111 | return r; | |
112 | ||
113 | /* Ignore mount points we can't unmount because they | |
114 | * are API or because we are keeping them open (like | |
115 | * /dev/console). Also, ignore all mounts below API | |
116 | * file systems, since they are likely virtual too, | |
117 | * and hence not worth spending time on. Also, in | |
118 | * unprivileged containers we might lack the rights to | |
119 | * unmount these things, hence don't bother. */ | |
120 | if (mount_point_is_api(p) || | |
121 | mount_point_ignore(p) || | |
122 | path_startswith(p, "/dev") || | |
123 | path_startswith(p, "/sys") || | |
124 | path_startswith(p, "/proc")) { | |
125 | free(p); | |
126 | continue; | |
127 | } | |
128 | ||
129 | m = new0(MountPoint, 1); | |
130 | if (!m) { | |
131 | free(p); | |
132 | return -ENOMEM; | |
133 | } | |
134 | ||
135 | m->path = p; | |
136 | m->options = options; | |
137 | options = NULL; | |
138 | m->type = type; | |
139 | type = NULL; | |
140 | ||
141 | LIST_PREPEND(mount_point, *head, m); | |
142 | } | |
143 | ||
144 | return 0; | |
145 | } | |
146 | ||
147 | static int swap_list_get(MountPoint **head) { | |
148 | _cleanup_fclose_ FILE *proc_swaps = NULL; | |
149 | unsigned int i; | |
150 | int r; | |
151 | ||
152 | assert(head); | |
153 | ||
154 | proc_swaps = fopen("/proc/swaps", "re"); | |
155 | if (!proc_swaps) | |
156 | return (errno == ENOENT) ? 0 : -errno; | |
157 | ||
158 | (void) fscanf(proc_swaps, "%*s %*s %*s %*s %*s\n"); | |
159 | ||
160 | for (i = 2;; i++) { | |
161 | MountPoint *swap; | |
162 | char *dev = NULL, *d; | |
163 | int k; | |
164 | ||
165 | k = fscanf(proc_swaps, | |
166 | "%ms " /* device/file */ | |
167 | "%*s " /* type of swap */ | |
168 | "%*s " /* swap size */ | |
169 | "%*s " /* used */ | |
170 | "%*s\n", /* priority */ | |
171 | &dev); | |
172 | ||
173 | if (k != 1) { | |
174 | if (k == EOF) | |
175 | break; | |
176 | ||
177 | log_warning("Failed to parse /proc/swaps:%u.", i); | |
178 | free(dev); | |
179 | continue; | |
180 | } | |
181 | ||
182 | if (endswith(dev, " (deleted)")) { | |
183 | free(dev); | |
184 | continue; | |
185 | } | |
186 | ||
187 | r = cunescape(dev, UNESCAPE_RELAX, &d); | |
188 | free(dev); | |
189 | if (r < 0) | |
190 | return r; | |
191 | ||
192 | swap = new0(MountPoint, 1); | |
193 | if (!swap) { | |
194 | free(d); | |
195 | return -ENOMEM; | |
196 | } | |
197 | ||
198 | swap->path = d; | |
199 | LIST_PREPEND(mount_point, *head, swap); | |
200 | } | |
201 | ||
202 | return 0; | |
203 | } | |
204 | ||
205 | static int loopback_list_get(MountPoint **head) { | |
206 | _cleanup_udev_enumerate_unref_ struct udev_enumerate *e = NULL; | |
207 | struct udev_list_entry *item = NULL, *first = NULL; | |
208 | _cleanup_udev_unref_ struct udev *udev = NULL; | |
209 | int r; | |
210 | ||
211 | assert(head); | |
212 | ||
213 | udev = udev_new(); | |
214 | if (!udev) | |
215 | return -ENOMEM; | |
216 | ||
217 | e = udev_enumerate_new(udev); | |
218 | if (!e) | |
219 | return -ENOMEM; | |
220 | ||
221 | r = udev_enumerate_add_match_subsystem(e, "block"); | |
222 | if (r < 0) | |
223 | return r; | |
224 | ||
225 | r = udev_enumerate_add_match_sysname(e, "loop*"); | |
226 | if (r < 0) | |
227 | return r; | |
228 | ||
229 | r = udev_enumerate_add_match_sysattr(e, "loop/backing_file", NULL); | |
230 | if (r < 0) | |
231 | return r; | |
232 | ||
233 | r = udev_enumerate_scan_devices(e); | |
234 | if (r < 0) | |
235 | return r; | |
236 | ||
237 | first = udev_enumerate_get_list_entry(e); | |
238 | udev_list_entry_foreach(item, first) { | |
239 | MountPoint *lb; | |
240 | _cleanup_udev_device_unref_ struct udev_device *d; | |
241 | char *loop; | |
242 | const char *dn; | |
243 | ||
244 | d = udev_device_new_from_syspath(udev, udev_list_entry_get_name(item)); | |
245 | if (!d) | |
246 | return -ENOMEM; | |
247 | ||
248 | dn = udev_device_get_devnode(d); | |
249 | if (!dn) | |
250 | continue; | |
251 | ||
252 | loop = strdup(dn); | |
253 | if (!loop) | |
254 | return -ENOMEM; | |
255 | ||
256 | lb = new0(MountPoint, 1); | |
257 | if (!lb) { | |
258 | free(loop); | |
259 | return -ENOMEM; | |
260 | } | |
261 | ||
262 | lb->path = loop; | |
263 | LIST_PREPEND(mount_point, *head, lb); | |
264 | } | |
265 | ||
266 | return 0; | |
267 | } | |
268 | ||
269 | static int dm_list_get(MountPoint **head) { | |
270 | _cleanup_udev_enumerate_unref_ struct udev_enumerate *e = NULL; | |
271 | struct udev_list_entry *item = NULL, *first = NULL; | |
272 | _cleanup_udev_unref_ struct udev *udev = NULL; | |
273 | int r; | |
274 | ||
275 | assert(head); | |
276 | ||
277 | udev = udev_new(); | |
278 | if (!udev) | |
279 | return -ENOMEM; | |
280 | ||
281 | e = udev_enumerate_new(udev); | |
282 | if (!e) | |
283 | return -ENOMEM; | |
284 | ||
285 | r = udev_enumerate_add_match_subsystem(e, "block"); | |
286 | if (r < 0) | |
287 | return r; | |
288 | ||
289 | r = udev_enumerate_add_match_sysname(e, "dm-*"); | |
290 | if (r < 0) | |
291 | return r; | |
292 | ||
293 | r = udev_enumerate_scan_devices(e); | |
294 | if (r < 0) | |
295 | return r; | |
296 | ||
297 | first = udev_enumerate_get_list_entry(e); | |
298 | udev_list_entry_foreach(item, first) { | |
299 | MountPoint *m; | |
300 | _cleanup_udev_device_unref_ struct udev_device *d; | |
301 | dev_t devnum; | |
302 | char *node; | |
303 | const char *dn; | |
304 | ||
305 | d = udev_device_new_from_syspath(udev, udev_list_entry_get_name(item)); | |
306 | if (!d) | |
307 | return -ENOMEM; | |
308 | ||
309 | devnum = udev_device_get_devnum(d); | |
310 | dn = udev_device_get_devnode(d); | |
311 | if (major(devnum) == 0 || !dn) | |
312 | continue; | |
313 | ||
314 | node = strdup(dn); | |
315 | if (!node) | |
316 | return -ENOMEM; | |
317 | ||
318 | m = new(MountPoint, 1); | |
319 | if (!m) { | |
320 | free(node); | |
321 | return -ENOMEM; | |
322 | } | |
323 | ||
324 | m->path = node; | |
325 | m->devnum = devnum; | |
326 | LIST_PREPEND(mount_point, *head, m); | |
327 | } | |
328 | ||
329 | return 0; | |
330 | } | |
331 | ||
332 | static int delete_loopback(const char *device) { | |
333 | _cleanup_close_ int fd = -1; | |
334 | int r; | |
335 | ||
336 | fd = open(device, O_RDONLY|O_CLOEXEC); | |
337 | if (fd < 0) | |
338 | return errno == ENOENT ? 0 : -errno; | |
339 | ||
340 | r = ioctl(fd, LOOP_CLR_FD, 0); | |
341 | if (r >= 0) | |
342 | return 1; | |
343 | ||
344 | /* ENXIO: not bound, so no error */ | |
345 | if (errno == ENXIO) | |
346 | return 0; | |
347 | ||
348 | return -errno; | |
349 | } | |
350 | ||
351 | static int delete_dm(dev_t devnum) { | |
352 | ||
353 | struct dm_ioctl dm = { | |
354 | .version = { | |
355 | DM_VERSION_MAJOR, | |
356 | DM_VERSION_MINOR, | |
357 | DM_VERSION_PATCHLEVEL | |
358 | }, | |
359 | .data_size = sizeof(dm), | |
360 | .dev = devnum, | |
361 | }; | |
362 | ||
363 | _cleanup_close_ int fd = -1; | |
364 | ||
365 | assert(major(devnum) != 0); | |
366 | ||
367 | fd = open("/dev/mapper/control", O_RDWR|O_CLOEXEC); | |
368 | if (fd < 0) | |
369 | return -errno; | |
370 | ||
371 | if (ioctl(fd, DM_DEV_REMOVE, &dm) < 0) | |
372 | return -errno; | |
373 | ||
374 | return 0; | |
375 | } | |
376 | ||
377 | static bool nonunmountable_path(const char *path) { | |
378 | return path_equal(path, "/") | |
379 | #if ! HAVE_SPLIT_USR | |
380 | || path_equal(path, "/usr") | |
381 | #endif | |
382 | || path_startswith(path, "/run/initramfs"); | |
383 | } | |
384 | ||
385 | /* This includes remounting readonly, which changes the kernel mount options. | |
386 | * Therefore the list passed to this function is invalidated, and should not be reused. */ | |
387 | ||
388 | static int mount_points_list_umount(MountPoint **head, bool *changed, bool log_error) { | |
389 | MountPoint *m; | |
390 | int n_failed = 0; | |
391 | ||
392 | assert(head); | |
393 | ||
394 | LIST_FOREACH(mount_point, m, *head) { | |
395 | bool mount_is_readonly; | |
396 | ||
397 | mount_is_readonly = fstab_test_yes_no_option(m->options, "ro\0rw\0"); | |
398 | ||
399 | /* If we are in a container, don't attempt to | |
400 | read-only mount anything as that brings no real | |
401 | benefits, but might confuse the host, as we remount | |
402 | the superblock here, not the bind mount. | |
403 | If the filesystem is a network fs, also skip the | |
404 | remount. It brings no value (we cannot leave | |
405 | a "dirty fs") and could hang if the network is down. | |
406 | Note that umount2() is more careful and will not | |
407 | hang because of the network being down. */ | |
408 | if (detect_container() <= 0 && | |
409 | !fstype_is_network(m->type) && | |
410 | !mount_is_readonly) { | |
411 | _cleanup_free_ char *options = NULL; | |
412 | /* MS_REMOUNT requires that the data parameter | |
413 | * should be the same from the original mount | |
414 | * except for the desired changes. Since we want | |
415 | * to remount read-only, we should filter out | |
416 | * rw (and ro too, because it confuses the kernel) */ | |
417 | (void) fstab_filter_options(m->options, "rw\0ro\0", NULL, NULL, &options); | |
418 | ||
419 | /* We always try to remount directories | |
420 | * read-only first, before we go on and umount | |
421 | * them. | |
422 | * | |
423 | * Mount points can be stacked. If a mount | |
424 | * point is stacked below / or /usr, we | |
425 | * cannot umount or remount it directly, | |
426 | * since there is no way to refer to the | |
427 | * underlying mount. There's nothing we can do | |
428 | * about it for the general case, but we can | |
429 | * do something about it if it is aliased | |
430 | * somehwere else via a bind mount. If we | |
431 | * explicitly remount the super block of that | |
432 | * alias read-only we hence should be | |
433 | * relatively safe regarding keeping dirty an fs | |
434 | * we cannot otherwise see. */ | |
435 | log_info("Remounting '%s' read-only with options '%s'.", m->path, options); | |
436 | if (mount(NULL, m->path, NULL, MS_REMOUNT|MS_RDONLY, options) < 0) { | |
437 | if (log_error) | |
438 | log_notice_errno(errno, "Failed to remount '%s' read-only: %m", m->path); | |
439 | if (nonunmountable_path(m->path)) | |
440 | n_failed++; | |
441 | } | |
442 | } | |
443 | ||
444 | /* Skip / and /usr since we cannot unmount that | |
445 | * anyway, since we are running from it. They have | |
446 | * already been remounted ro. */ | |
447 | if (nonunmountable_path(m->path)) | |
448 | continue; | |
449 | ||
450 | /* Trying to umount. Using MNT_FORCE causes some | |
451 | * filesystems (e.g. FUSE and NFS and other network | |
452 | * filesystems) to abort any pending requests and | |
453 | * return -EIO rather than blocking indefinitely. | |
454 | * If the filesysten is "busy", this may allow processes | |
455 | * to die, thus making the filesystem less busy so | |
456 | * the unmount might succeed (rather then return EBUSY).*/ | |
457 | log_info("Unmounting %s.", m->path); | |
458 | if (umount2(m->path, MNT_FORCE) == 0) { | |
459 | if (changed) | |
460 | *changed = true; | |
461 | } else { | |
462 | if (log_error) | |
463 | log_warning_errno(errno, "Could not unmount %s: %m", m->path); | |
464 | n_failed++; | |
465 | } | |
466 | } | |
467 | ||
468 | return n_failed; | |
469 | } | |
470 | ||
471 | static int swap_points_list_off(MountPoint **head, bool *changed) { | |
472 | MountPoint *m, *n; | |
473 | int n_failed = 0; | |
474 | ||
475 | assert(head); | |
476 | ||
477 | LIST_FOREACH_SAFE(mount_point, m, n, *head) { | |
478 | log_info("Deactivating swap %s.", m->path); | |
479 | if (swapoff(m->path) == 0) { | |
480 | if (changed) | |
481 | *changed = true; | |
482 | ||
483 | mount_point_free(head, m); | |
484 | } else { | |
485 | log_warning_errno(errno, "Could not deactivate swap %s: %m", m->path); | |
486 | n_failed++; | |
487 | } | |
488 | } | |
489 | ||
490 | return n_failed; | |
491 | } | |
492 | ||
493 | static int loopback_points_list_detach(MountPoint **head, bool *changed) { | |
494 | MountPoint *m, *n; | |
495 | int n_failed = 0, k; | |
496 | struct stat root_st; | |
497 | ||
498 | assert(head); | |
499 | ||
500 | k = lstat("/", &root_st); | |
501 | ||
502 | LIST_FOREACH_SAFE(mount_point, m, n, *head) { | |
503 | int r; | |
504 | struct stat loopback_st; | |
505 | ||
506 | if (k >= 0 && | |
507 | major(root_st.st_dev) != 0 && | |
508 | lstat(m->path, &loopback_st) >= 0 && | |
509 | root_st.st_dev == loopback_st.st_rdev) { | |
510 | n_failed++; | |
511 | continue; | |
512 | } | |
513 | ||
514 | log_info("Detaching loopback %s.", m->path); | |
515 | r = delete_loopback(m->path); | |
516 | if (r >= 0) { | |
517 | if (r > 0 && changed) | |
518 | *changed = true; | |
519 | ||
520 | mount_point_free(head, m); | |
521 | } else { | |
522 | log_warning_errno(errno, "Could not detach loopback %s: %m", m->path); | |
523 | n_failed++; | |
524 | } | |
525 | } | |
526 | ||
527 | return n_failed; | |
528 | } | |
529 | ||
530 | static int dm_points_list_detach(MountPoint **head, bool *changed) { | |
531 | MountPoint *m, *n; | |
532 | int n_failed = 0, r; | |
533 | dev_t rootdev; | |
534 | ||
535 | assert(head); | |
536 | ||
537 | r = get_block_device("/", &rootdev); | |
538 | if (r <= 0) | |
539 | rootdev = 0; | |
540 | ||
541 | LIST_FOREACH_SAFE(mount_point, m, n, *head) { | |
542 | ||
543 | if (major(rootdev) != 0) | |
544 | if (rootdev == m->devnum) { | |
545 | n_failed ++; | |
546 | continue; | |
547 | } | |
548 | ||
549 | log_info("Detaching DM %u:%u.", major(m->devnum), minor(m->devnum)); | |
550 | r = delete_dm(m->devnum); | |
551 | if (r >= 0) { | |
552 | if (changed) | |
553 | *changed = true; | |
554 | ||
555 | mount_point_free(head, m); | |
556 | } else { | |
557 | log_warning_errno(errno, "Could not detach DM %s: %m", m->path); | |
558 | n_failed++; | |
559 | } | |
560 | } | |
561 | ||
562 | return n_failed; | |
563 | } | |
564 | ||
565 | static int umount_all_once(bool *changed, bool log_error) { | |
566 | int r; | |
567 | LIST_HEAD(MountPoint, mp_list_head); | |
568 | ||
569 | LIST_HEAD_INIT(mp_list_head); | |
570 | r = mount_points_list_get(&mp_list_head); | |
571 | if (r < 0) | |
572 | goto end; | |
573 | ||
574 | r = mount_points_list_umount(&mp_list_head, changed, log_error); | |
575 | ||
576 | end: | |
577 | mount_points_list_free(&mp_list_head); | |
578 | ||
579 | return r; | |
580 | } | |
581 | ||
582 | int umount_all(bool *changed) { | |
583 | bool umount_changed; | |
584 | int r; | |
585 | ||
586 | /* retry umount, until nothing can be umounted anymore */ | |
587 | do { | |
588 | umount_changed = false; | |
589 | ||
590 | umount_all_once(&umount_changed, false); | |
591 | if (umount_changed) | |
592 | *changed = true; | |
593 | } while (umount_changed); | |
594 | ||
595 | /* umount one more time with logging enabled */ | |
596 | r = umount_all_once(&umount_changed, true); | |
597 | if (umount_changed) | |
598 | *changed = true; | |
599 | ||
600 | return r; | |
601 | } | |
602 | ||
603 | int swapoff_all(bool *changed) { | |
604 | int r; | |
605 | LIST_HEAD(MountPoint, swap_list_head); | |
606 | ||
607 | LIST_HEAD_INIT(swap_list_head); | |
608 | ||
609 | r = swap_list_get(&swap_list_head); | |
610 | if (r < 0) | |
611 | goto end; | |
612 | ||
613 | r = swap_points_list_off(&swap_list_head, changed); | |
614 | ||
615 | end: | |
616 | mount_points_list_free(&swap_list_head); | |
617 | ||
618 | return r; | |
619 | } | |
620 | ||
621 | int loopback_detach_all(bool *changed) { | |
622 | int r; | |
623 | LIST_HEAD(MountPoint, loopback_list_head); | |
624 | ||
625 | LIST_HEAD_INIT(loopback_list_head); | |
626 | ||
627 | r = loopback_list_get(&loopback_list_head); | |
628 | if (r < 0) | |
629 | goto end; | |
630 | ||
631 | r = loopback_points_list_detach(&loopback_list_head, changed); | |
632 | ||
633 | end: | |
634 | mount_points_list_free(&loopback_list_head); | |
635 | ||
636 | return r; | |
637 | } | |
638 | ||
639 | int dm_detach_all(bool *changed) { | |
640 | int r; | |
641 | LIST_HEAD(MountPoint, dm_list_head); | |
642 | ||
643 | LIST_HEAD_INIT(dm_list_head); | |
644 | ||
645 | r = dm_list_get(&dm_list_head); | |
646 | if (r < 0) | |
647 | goto end; | |
648 | ||
649 | r = dm_points_list_detach(&dm_list_head, changed); | |
650 | ||
651 | end: | |
652 | mount_points_list_free(&dm_list_head); | |
653 | ||
654 | return r; | |
655 | } |