summaryrefslogtreecommitdiff
path: root/src/core/umount.c
blob: f6c520eaa855d1a9e4dd167df9780b502a562694 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/

/***
  This file is part of systemd.

  Copyright 2010 ProFUSION embedded systems

  systemd is free software; you can redistribute it and/or modify it
  under the terms of the GNU Lesser General Public License as published by
  the Free Software Foundation; either version 2.1 of the License, or
  (at your option) any later version.

  systemd is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public License
  along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/

#include <errno.h>
#include <fcntl.h>
#include <string.h>
#include <sys/mount.h>
#include <sys/swap.h>
#include <unistd.h>
#include <linux/loop.h>
#include <linux/dm-ioctl.h>
#include <libudev.h>

#include "list.h"
#include "mount-setup.h"
#include "umount.h"
#include "path-util.h"
#include "util.h"
#include "virt.h"

typedef struct MountPoint {
        char *path;
        dev_t devnum;
        LIST_FIELDS (struct MountPoint, mount_point);
} MountPoint;

static void mount_point_free(MountPoint **head, MountPoint *m) {
        assert(head);
        assert(m);

        LIST_REMOVE(MountPoint, mount_point, *head, m);

        free(m->path);
        free(m);
}

static void mount_points_list_free(MountPoint **head) {
        assert(head);

        while (*head)
                mount_point_free(head, *head);
}

static int mount_points_list_get(MountPoint **head) {
        FILE *proc_self_mountinfo;
        char *path, *p;
        unsigned int i;
        int r;

        assert(head);

        if (!(proc_self_mountinfo = fopen("/proc/self/mountinfo", "re")))
                return -errno;

        for (i = 1;; i++) {
                int k;
                MountPoint *m;

                path = p = NULL;

                if ((k = fscanf(proc_self_mountinfo,
                                "%*s "       /* (1) mount id */
                                "%*s "       /* (2) parent id */
                                "%*s "       /* (3) major:minor */
                                "%*s "       /* (4) root */
                                "%ms "       /* (5) mount point */
                                "%*s"        /* (6) mount options */
                                "%*[^-]"     /* (7) optional fields */
                                "- "         /* (8) separator */
                                "%*s "       /* (9) file system type */
                                "%*s"        /* (10) mount source */
                                "%*s"        /* (11) mount options 2 */
                                "%*[^\n]",   /* some rubbish at the end */
                                &path)) != 1) {
                        if (k == EOF)
                                break;

                        log_warning("Failed to parse /proc/self/mountinfo:%u.", i);

                        free(path);
                        continue;
                }

                p = cunescape(path);
                free(path);

                if (!p) {
                        r = -ENOMEM;
                        goto finish;
                }

                /* Ignore mount points we can't unmount because they
                 * are API or because we are keeping them open (like
                 * /dev/console) */
                if (mount_point_is_api(p) ||
                    mount_point_ignore(p) ||
                    path_equal(p, "/dev/console")) {
                        free(p);
                        continue;
                }

                if (!(m = new0(MountPoint, 1))) {
                        free(p);
                        r = -ENOMEM;
                        goto finish;
                }

                m->path = p;
                LIST_PREPEND(MountPoint, mount_point, *head, m);
        }

        r = 0;

finish:
        fclose(proc_self_mountinfo);

        return r;
}

static int swap_list_get(MountPoint **head) {
        FILE *proc_swaps;
        unsigned int i;
        int r;

        assert(head);

        if (!(proc_swaps = fopen("/proc/swaps", "re")))
                return (errno == ENOENT) ? 0 : -errno;

        (void) fscanf(proc_swaps, "%*s %*s %*s %*s %*s\n");

        for (i = 2;; i++) {
                MountPoint *swap;
                char *dev = NULL, *d;
                int k;

                if ((k = fscanf(proc_swaps,
                                "%ms " /* device/file */
                                "%*s " /* type of swap */
                                "%*s " /* swap size */
                                "%*s " /* used */
                                "%*s\n", /* priority */
                                &dev)) != 1) {

                        if (k == EOF)
                                break;

                        log_warning("Failed to parse /proc/swaps:%u.", i);

                        free(dev);
                        continue;
                }

                if (endswith(dev, "(deleted)")) {
                        free(dev);
                        continue;
                }

                d = cunescape(dev);
                free(dev);

                if (!d) {
                        r = -ENOMEM;
                        goto finish;
                }

                if (!(swap = new0(MountPoint, 1))) {
                        free(d);
                        r = -ENOMEM;
                        goto finish;
                }

                swap->path = d;
                LIST_PREPEND(MountPoint, mount_point, *head, swap);
        }

        r = 0;

finish:
        fclose(proc_swaps);

        return r;
}

static int loopback_list_get(MountPoint **head) {
        int r;
        struct udev *udev;
        struct udev_enumerate *e = NULL;
        struct udev_list_entry *item = NULL, *first = NULL;

        assert(head);

        if (!(udev = udev_new())) {
                r = -ENOMEM;
                goto finish;
        }

        if (!(e = udev_enumerate_new(udev))) {
                r = -ENOMEM;
                goto finish;
        }

        if (udev_enumerate_add_match_subsystem(e, "block") < 0 ||
            udev_enumerate_add_match_sysname(e, "loop*") < 0) {
                r = -EIO;
                goto finish;
        }

        if (udev_enumerate_scan_devices(e) < 0) {
                r = -EIO;
                goto finish;
        }

        first = udev_enumerate_get_list_entry(e);
        udev_list_entry_foreach(item, first) {
                MountPoint *lb;
                struct udev_device *d;
                char *loop;
                const char *dn;

                if (!(d = udev_device_new_from_syspath(udev, udev_list_entry_get_name(item)))) {
                        r = -ENOMEM;
                        goto finish;
                }

                if (!(dn = udev_device_get_devnode(d))) {
                        udev_device_unref(d);
                        continue;
                }

                loop = strdup(dn);
                udev_device_unref(d);

                if (!loop) {
                        r = -ENOMEM;
                        goto finish;
                }

                if (!(lb = new0(MountPoint, 1))) {
                        free(loop);
                        r = -ENOMEM;
                        goto finish;
                }

                lb->path = loop;
                LIST_PREPEND(MountPoint, mount_point, *head, lb);
        }

        r = 0;

finish:
        if (e)
                udev_enumerate_unref(e);

        if (udev)
                udev_unref(udev);

        return r;
}

static int dm_list_get(MountPoint **head) {
        int r;
        struct udev *udev;
        struct udev_enumerate *e = NULL;
        struct udev_list_entry *item = NULL, *first = NULL;

        assert(head);

        if (!(udev = udev_new())) {
                r = -ENOMEM;
                goto finish;
        }

        if (!(e = udev_enumerate_new(udev))) {
                r = -ENOMEM;
                goto finish;
        }

        if (udev_enumerate_add_match_subsystem(e, "block") < 0 ||
            udev_enumerate_add_match_sysname(e, "dm-*") < 0) {
                r = -EIO;
                goto finish;
        }

        if (udev_enumerate_scan_devices(e) < 0) {
                r = -EIO;
                goto finish;
        }

        first = udev_enumerate_get_list_entry(e);

        udev_list_entry_foreach(item, first) {
                MountPoint *m;
                struct udev_device *d;
                dev_t devnum;
                char *node;
                const char *dn;

                if (!(d = udev_device_new_from_syspath(udev, udev_list_entry_get_name(item)))) {
                        r = -ENOMEM;
                        goto finish;
                }

                devnum = udev_device_get_devnum(d);
                dn = udev_device_get_devnode(d);

                if (major(devnum) == 0 || !dn) {
                        udev_device_unref(d);
                        continue;
                }

                node = strdup(dn);
                udev_device_unref(d);

                if (!node) {
                        r = -ENOMEM;
                        goto finish;
                }

                if (!(m = new(MountPoint, 1))) {
                        free(node);
                        r = -ENOMEM;
                        goto finish;
                }

                m->path = node;
                m->devnum = devnum;
                LIST_PREPEND(MountPoint, mount_point, *head, m);
        }

        r = 0;

finish:
        if (e)
                udev_enumerate_unref(e);

        if (udev)
                udev_unref(udev);

        return r;
}

static int delete_loopback(const char *device) {
        int fd, r;

        if ((fd = open(device, O_RDONLY|O_CLOEXEC)) < 0)
                return errno == ENOENT ? 0 : -errno;

        r = ioctl(fd, LOOP_CLR_FD, 0);
        close_nointr_nofail(fd);

        if (r >= 0)
                return 1;

        /* ENXIO: not bound, so no error */
        if (errno == ENXIO)
                return 0;

        return -errno;
}

static int delete_dm(dev_t devnum) {
        int fd, r;
        struct dm_ioctl dm;

        assert(major(devnum) != 0);

        if ((fd = open("/dev/mapper/control", O_RDWR|O_CLOEXEC)) < 0)
                return -errno;

        zero(dm);
        dm.version[0] = DM_VERSION_MAJOR;
        dm.version[1] = DM_VERSION_MINOR;
        dm.version[2] = DM_VERSION_PATCHLEVEL;

        dm.data_size = sizeof(dm);
        dm.dev = devnum;

        r = ioctl(fd, DM_DEV_REMOVE, &dm);
        close_nointr_nofail(fd);

        return r >= 0 ? 0 : -errno;
}

static int mount_points_list_umount(MountPoint **head, bool *changed, bool log_error) {
        MountPoint *m, *n;
        int n_failed = 0;

        assert(head);

        LIST_FOREACH_SAFE(mount_point, m, n, *head) {

                /* If we are in a container, don't attempt to
                   read-only mount anything as that brings no real
                   benefits, but might confuse the host, as we remount
                   the superblock here, not the bind mound. */
                if (detect_container(NULL) <= 0)  {
                        /* We always try to remount directories
                         * read-only first, before we go on and umount
                         * them.
                         *
                         * Mount points can be stacked. If a mount
                         * point is stacked below / or /usr, we
                         * cannnot umount or remount it directly,
                         * since there is no way to refer to the
                         * underlying mount. There's nothing we can do
                         * about it for the general case, but we can
                         * do something about it if it is aliased
                         * somehwere else via a bind mount. If we
                         * explicitly remount the super block of that
                         * alias read-only we hence should be
                         * relatively safe regarding keeping the fs we
                         * can otherwise not see dirty. */
                        mount(NULL, m->path, NULL, MS_REMOUNT|MS_RDONLY, NULL);
                }

                /* Skip / and /usr since we cannot unmount that
                 * anyway, since we are running from it. They have
                 * already been remounted ro. */
                if (path_equal(m->path, "/")
#ifndef HAVE_SPLIT_USR
                    || path_equal(m->path, "/usr")
#endif
                )
                        continue;

                /* Trying to umount. Forcing to umount if busy (only for NFS mounts) */
                if (umount2(m->path, MNT_FORCE) == 0) {
                        log_info("Unmounted %s.", m->path);
                        if (changed)
                                *changed = true;

                        mount_point_free(head, m);
                } else if (log_error) {
                        log_warning("Could not unmount %s: %m", m->path);
                        n_failed++;
                }
        }

        return n_failed;
}

static int swap_points_list_off(MountPoint **head, bool *changed) {
        MountPoint *m, *n;
        int n_failed = 0;

        assert(head);

        LIST_FOREACH_SAFE(mount_point, m, n, *head) {
                if (swapoff(m->path) == 0) {
                        if (changed)
                                *changed = true;

                        mount_point_free(head, m);
                } else {
                        log_warning("Could not deactivate swap %s: %m", m->path);
                        n_failed++;
                }
        }

        return n_failed;
}

static int loopback_points_list_detach(MountPoint **head, bool *changed) {
        MountPoint *m, *n;
        int n_failed = 0, k;
        struct stat root_st;

        assert(head);

        k = lstat("/", &root_st);

        LIST_FOREACH_SAFE(mount_point, m, n, *head) {
                int r;
                struct stat loopback_st;

                if (k >= 0 &&
                    major(root_st.st_dev) != 0 &&
                    lstat(m->path, &loopback_st) >= 0 &&
                    root_st.st_dev == loopback_st.st_rdev) {
                        n_failed ++;
                        continue;
                }

                if ((r = delete_loopback(m->path)) >= 0) {

                        if (r > 0 && changed)
                                *changed = true;

                        mount_point_free(head, m);
                } else {
                        log_warning("Could not delete loopback %s: %m", m->path);
                        n_failed++;
                }
        }

        return n_failed;
}

static int dm_points_list_detach(MountPoint **head, bool *changed) {
        MountPoint *m, *n;
        int n_failed = 0, k;
        struct stat root_st;

        assert(head);

        k = lstat("/", &root_st);

        LIST_FOREACH_SAFE(mount_point, m, n, *head) {
                int r;

                if (k >= 0 &&
                    major(root_st.st_dev) != 0 &&
                    root_st.st_dev == m->devnum) {
                        n_failed ++;
                        continue;
                }

                if ((r = delete_dm(m->devnum)) >= 0) {

                        if (r > 0 && changed)
                                *changed = true;

                        mount_point_free(head, m);
                } else {
                        log_warning("Could not delete dm %s: %m", m->path);
                        n_failed++;
                }
        }

        return n_failed;
}

int umount_all(bool *changed) {
        int r;
        bool umount_changed;
        LIST_HEAD(MountPoint, mp_list_head);

        LIST_HEAD_INIT(MountPoint, mp_list_head);
        r = mount_points_list_get(&mp_list_head);
        if (r < 0)
                goto end;

        /* retry umount, until nothing can be umounted anymore */
        do {
                umount_changed = false;

                mount_points_list_umount(&mp_list_head, &umount_changed, false);
                if (umount_changed)
                        *changed = true;

        } while (umount_changed);

        /* umount one more time with logging enabled */
        r = mount_points_list_umount(&mp_list_head, &umount_changed, true);
        if (r <= 0)
                goto end;

  end:
        mount_points_list_free(&mp_list_head);

        return r;
}

int swapoff_all(bool *changed) {
        int r;
        LIST_HEAD(MountPoint, swap_list_head);

        LIST_HEAD_INIT(MountPoint, swap_list_head);

        r = swap_list_get(&swap_list_head);
        if (r < 0)
                goto end;

        r = swap_points_list_off(&swap_list_head, changed);

  end:
        mount_points_list_free(&swap_list_head);

        return r;
}

int loopback_detach_all(bool *changed) {
        int r;
        LIST_HEAD(MountPoint, loopback_list_head);

        LIST_HEAD_INIT(MountPoint, loopback_list_head);

        r = loopback_list_get(&loopback_list_head);
        if (r < 0)
                goto end;

        r = loopback_points_list_detach(&loopback_list_head, changed);

  end:
        mount_points_list_free(&loopback_list_head);

        return r;
}

int dm_detach_all(bool *changed) {
        int r;
        LIST_HEAD(MountPoint, dm_list_head);

        LIST_HEAD_INIT(MountPoint, dm_list_head);

        r = dm_list_get(&dm_list_head);
        if (r < 0)
                goto end;

        r = dm_points_list_detach(&dm_list_head, changed);

  end:
        mount_points_list_free(&dm_list_head);

        return r;
}