src/core/umount.c

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