src/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 "util.h"
  36
  37 typedef struct MountPoint {
  38         char *path;
  39         dev_t devnum;
  40         bool skip_ro;
  41         LIST_FIELDS (struct MountPoint, mount_point);
  42 } MountPoint;
  43
  44 static void mount_point_free(MountPoint **head, MountPoint *m) {
  45         assert(head);
  46         assert(m);
  47
  48         LIST_REMOVE(MountPoint, mount_point, *head, m);
  49
  50         free(m->path);
  51         free(m);
  52 }
  53
  54 static void mount_points_list_free(MountPoint **head) {
  55         assert(head);
  56
  57         while (*head)
  58                 mount_point_free(head, *head);
  59 }
  60
  61 static int mount_points_list_get(MountPoint **head) {
  62         FILE *proc_self_mountinfo;
  63         char *path, *p;
  64         unsigned int i;
  65         int r;
  66
  67         assert(head);
  68
  69         if (!(proc_self_mountinfo = fopen("/proc/self/mountinfo", "re")))
  70                 return -errno;
  71
  72         for (i = 1;; i++) {
  73                 int k;
  74                 MountPoint *m;
  75                 char *root;
  76                 bool skip_ro;
  77
  78                 path = p = NULL;
  79
  80                 if ((k = fscanf(proc_self_mountinfo,
  81                                 "%*s "       /* (1) mount id */
  82                                 "%*s "       /* (2) parent id */
  83                                 "%*s "       /* (3) major:minor */
  84                                 "%ms "       /* (4) root */
  85                                 "%ms "       /* (5) mount point */
  86                                 "%*s"        /* (6) mount options */
  87                                 "%*[^-]"     /* (7) optional fields */
  88                                 "- "         /* (8) separator */
  89                                 "%*s "       /* (9) file system type */
  90                                 "%*s"        /* (10) mount source */
  91                                 "%*s"        /* (11) mount options 2 */
  92                                 "%*[^\n]",   /* some rubbish at the end */
  93                                 &root,
  94                                 &path)) != 2) {
  95                         if (k == EOF)
  96                                 break;
  97
  98                         log_warning("Failed to parse /proc/self/mountinfo:%u.", i);
  99
 100                         free(path);
 101                         continue;
 102                 }
 103
 104                 /* If we encounter a bind mount, don't try to remount
 105                  * the source dir too early */
 106                 skip_ro = !streq(root, "/");
 107                 free(root);
 108
 109                 p = cunescape(path);
 110                 free(path);
 111
 112                 if (!p) {
 113                         r = -ENOMEM;
 114                         goto finish;
 115                 }
 116
 117                 if (mount_point_is_api(p) || mount_point_ignore(p)) {
 118                         free(p);
 119                         continue;
 120                 }
 121
 122                 if (!(m = new0(MountPoint, 1))) {
 123                         free(p);
 124                         r = -ENOMEM;
 125                         goto finish;
 126                 }
 127
 128                 m->path = p;
 129                 m->skip_ro = skip_ro;
 130                 LIST_PREPEND(MountPoint, mount_point, *head, m);
 131         }
 132
 133         r = 0;
 134
 135 finish:
 136         fclose(proc_self_mountinfo);
 137
 138         return r;
 139 }
 140
 141 static int swap_list_get(MountPoint **head) {
 142         FILE *proc_swaps;
 143         unsigned int i;
 144         int r;
 145
 146         assert(head);
 147
 148         if (!(proc_swaps = fopen("/proc/swaps", "re")))
 149                 return (errno == ENOENT) ? 0 : -errno;
 150
 151         (void) fscanf(proc_swaps, "%*s %*s %*s %*s %*s\n");
 152
 153         for (i = 2;; i++) {
 154                 MountPoint *swap;
 155                 char *dev = NULL, *d;
 156                 int k;
 157
 158                 if ((k = fscanf(proc_swaps,
 159                                 "%ms " /* device/file */
 160                                 "%*s " /* type of swap */
 161                                 "%*s " /* swap size */
 162                                 "%*s " /* used */
 163                                 "%*s\n", /* priority */
 164                                 &dev)) != 1) {
 165
 166                         if (k == EOF)
 167                                 break;
 168
 169                         log_warning("Failed to parse /proc/swaps:%u.", i);
 170
 171                         free(dev);
 172                         continue;
 173                 }
 174
 175                 if (endswith(dev, "(deleted)")) {
 176                         free(dev);
 177                         continue;
 178                 }
 179
 180                 d = cunescape(dev);
 181                 free(dev);
 182
 183                 if (!d) {
 184                         r = -ENOMEM;
 185                         goto finish;
 186                 }
 187
 188                 if (!(swap = new0(MountPoint, 1))) {
 189                         free(d);
 190                         r = -ENOMEM;
 191                         goto finish;
 192                 }
 193
 194                 swap->path = d;
 195                 LIST_PREPEND(MountPoint, mount_point, *head, swap);
 196         }
 197
 198         r = 0;
 199
 200 finish:
 201         fclose(proc_swaps);
 202
 203         return r;
 204 }
 205
 206 static int loopback_list_get(MountPoint **head) {
 207         int r;
 208         struct udev *udev;
 209         struct udev_enumerate *e = NULL;
 210         struct udev_list_entry *item = NULL, *first = NULL;
 211
 212         assert(head);
 213
 214         if (!(udev = udev_new())) {
 215                 r = -ENOMEM;
 216                 goto finish;
 217         }
 218
 219         if (!(e = udev_enumerate_new(udev))) {
 220                 r = -ENOMEM;
 221                 goto finish;
 222         }
 223
 224         if (udev_enumerate_add_match_subsystem(e, "block") < 0 ||
 225             udev_enumerate_add_match_sysname(e, "loop*") < 0) {
 226                 r = -EIO;
 227                 goto finish;
 228         }
 229
 230         if (udev_enumerate_scan_devices(e) < 0) {
 231                 r = -EIO;
 232                 goto finish;
 233         }
 234
 235         first = udev_enumerate_get_list_entry(e);
 236         udev_list_entry_foreach(item, first) {
 237                 MountPoint *lb;
 238                 struct udev_device *d;
 239                 char *loop;
 240                 const char *dn;
 241
 242                 if (!(d = udev_device_new_from_syspath(udev, udev_list_entry_get_name(item)))) {
 243                         r = -ENOMEM;
 244                         goto finish;
 245                 }
 246
 247                 if (!(dn = udev_device_get_devnode(d))) {
 248                         udev_device_unref(d);
 249                         continue;
 250                 }
 251
 252                 loop = strdup(dn);
 253                 udev_device_unref(d);
 254
 255                 if (!loop) {
 256                         r = -ENOMEM;
 257                         goto finish;
 258                 }
 259
 260                 if (!(lb = new0(MountPoint, 1))) {
 261                         free(loop);
 262                         r = -ENOMEM;
 263                         goto finish;
 264                 }
 265
 266                 lb->path = loop;
 267                 LIST_PREPEND(MountPoint, mount_point, *head, lb);
 268         }
 269
 270         r = 0;
 271
 272 finish:
 273         if (e)
 274                 udev_enumerate_unref(e);
 275
 276         if (udev)
 277                 udev_unref(udev);
 278
 279         return r;
 280 }
 281
 282 static int dm_list_get(MountPoint **head) {
 283         int r;
 284         struct udev *udev;
 285         struct udev_enumerate *e = NULL;
 286         struct udev_list_entry *item = NULL, *first = NULL;
 287
 288         assert(head);
 289
 290         if (!(udev = udev_new())) {
 291                 r = -ENOMEM;
 292                 goto finish;
 293         }
 294
 295         if (!(e = udev_enumerate_new(udev))) {
 296                 r = -ENOMEM;
 297                 goto finish;
 298         }
 299
 300         if (udev_enumerate_add_match_subsystem(e, "block") < 0 ||
 301             udev_enumerate_add_match_sysname(e, "dm-*") < 0) {
 302                 r = -EIO;
 303                 goto finish;
 304         }
 305
 306         if (udev_enumerate_scan_devices(e) < 0) {
 307                 r = -EIO;
 308                 goto finish;
 309         }
 310
 311         first = udev_enumerate_get_list_entry(e);
 312
 313         udev_list_entry_foreach(item, first) {
 314                 MountPoint *m;
 315                 struct udev_device *d;
 316                 dev_t devnum;
 317                 char *node;
 318                 const char *dn;
 319
 320                 if (!(d = udev_device_new_from_syspath(udev, udev_list_entry_get_name(item)))) {
 321                         r = -ENOMEM;
 322                         goto finish;
 323                 }
 324
 325                 devnum = udev_device_get_devnum(d);
 326                 dn = udev_device_get_devnode(d);
 327
 328                 if (major(devnum) == 0 || !dn) {
 329                         udev_device_unref(d);
 330                         continue;
 331                 }
 332
 333                 node = strdup(dn);
 334                 udev_device_unref(d);
 335
 336                 if (!node) {
 337                         r = -ENOMEM;
 338                         goto finish;
 339                 }
 340
 341                 if (!(m = new(MountPoint, 1))) {
 342                         free(node);
 343                         r = -ENOMEM;
 344                         goto finish;
 345                 }
 346
 347                 m->path = node;
 348                 m->devnum = devnum;
 349                 LIST_PREPEND(MountPoint, mount_point, *head, m);
 350         }
 351
 352         r = 0;
 353
 354 finish:
 355         if (e)
 356                 udev_enumerate_unref(e);
 357
 358         if (udev)
 359                 udev_unref(udev);
 360
 361         return r;
 362 }
 363
 364 static int delete_loopback(const char *device) {
 365         int fd, r;
 366
 367         if ((fd = open(device, O_RDONLY|O_CLOEXEC)) < 0)
 368                 return errno == ENOENT ? 0 : -errno;
 369
 370         r = ioctl(fd, LOOP_CLR_FD, 0);
 371         close_nointr_nofail(fd);
 372
 373         if (r >= 0)
 374                 return 1;
 375
 376         /* ENXIO: not bound, so no error */
 377         if (errno == ENXIO)
 378                 return 0;
 379
 380         return -errno;
 381 }
 382
 383 static int delete_dm(dev_t devnum) {
 384         int fd, r;
 385         struct dm_ioctl dm;
 386
 387         assert(major(devnum) != 0);
 388
 389         if ((fd = open("/dev/mapper/control", O_RDWR|O_CLOEXEC)) < 0)
 390                 return -errno;
 391
 392         zero(dm);
 393         dm.version[0] = DM_VERSION_MAJOR;
 394         dm.version[1] = DM_VERSION_MINOR;
 395         dm.version[2] = DM_VERSION_PATCHLEVEL;
 396
 397         dm.data_size = sizeof(dm);
 398         dm.dev = devnum;
 399
 400         r = ioctl(fd, DM_DEV_REMOVE, &dm);
 401         close_nointr_nofail(fd);
 402
 403         return r >= 0 ? 0 : -errno;
 404 }
 405
 406 static int mount_points_list_umount(MountPoint **head, bool *changed, bool log_error) {
 407         MountPoint *m, *n;
 408         int n_failed = 0;
 409
 410         assert(head);
 411
 412         LIST_FOREACH_SAFE(mount_point, m, n, *head) {
 413                 if (path_equal(m->path, "/")
 414 #ifndef HAVE_SPLIT_USR
 415                     || path_equal(m->path, "/usr")
 416 #endif
 417                 ) {
 418                         n_failed++;
 419                         continue;
 420                 }
 421
 422                 /* Trying to umount. Forcing to umount if busy (only for NFS mounts) */
 423                 if (umount2(m->path, MNT_FORCE) == 0) {
 424                         log_info("Unmounted %s.", m->path);
 425                         if (changed)
 426                                 *changed = true;
 427
 428                         mount_point_free(head, m);
 429                 } else if (log_error) {
 430                         log_warning("Could not unmount %s: %m", m->path);
 431                         n_failed++;
 432                 }
 433         }
 434
 435         return n_failed;
 436 }
 437
 438 static int mount_points_list_remount_read_only(MountPoint **head, bool *changed) {
 439         MountPoint *m, *n;
 440         int n_failed = 0;
 441
 442         assert(head);
 443
 444         LIST_FOREACH_SAFE(mount_point, m, n, *head) {
 445
 446                 if (m->skip_ro) {
 447                         n_failed++;
 448                         continue;
 449                 }
 450
 451                 /* Trying to remount read-only */
 452                 if (mount(NULL, m->path, NULL, MS_MGC_VAL|MS_REMOUNT|MS_RDONLY, NULL) == 0) {
 453                         if (changed)
 454                                 *changed = true;
 455
 456                         mount_point_free(head, m);
 457                 } else {
 458                         log_warning("Could not remount as read-only %s: %m", m->path);
 459                         n_failed++;
 460                 }
 461         }
 462
 463         return n_failed;
 464 }
 465
 466 static int swap_points_list_off(MountPoint **head, bool *changed) {
 467         MountPoint *m, *n;
 468         int n_failed = 0;
 469
 470         assert(head);
 471
 472         LIST_FOREACH_SAFE(mount_point, m, n, *head) {
 473                 if (swapoff(m->path) == 0) {
 474                         if (changed)
 475                                 *changed = true;
 476
 477                         mount_point_free(head, m);
 478                 } else {
 479                         log_warning("Could not deactivate swap %s: %m", m->path);
 480                         n_failed++;
 481                 }
 482         }
 483
 484         return n_failed;
 485 }
 486
 487 static int loopback_points_list_detach(MountPoint **head, bool *changed) {
 488         MountPoint *m, *n;
 489         int n_failed = 0, k;
 490         struct stat root_st;
 491
 492         assert(head);
 493
 494         k = lstat("/", &root_st);
 495
 496         LIST_FOREACH_SAFE(mount_point, m, n, *head) {
 497                 int r;
 498                 struct stat loopback_st;
 499
 500                 if (k >= 0 &&
 501                     major(root_st.st_dev) != 0 &&
 502                     lstat(m->path, &loopback_st) >= 0 &&
 503                     root_st.st_dev == loopback_st.st_rdev) {
 504                         n_failed ++;
 505                         continue;
 506                 }
 507
 508                 if ((r = delete_loopback(m->path)) >= 0) {
 509
 510                         if (r > 0 && changed)
 511                                 *changed = true;
 512
 513                         mount_point_free(head, m);
 514                 } else {
 515                         log_warning("Could not delete loopback %s: %m", m->path);
 516                         n_failed++;
 517                 }
 518         }
 519
 520         return n_failed;
 521 }
 522
 523 static int dm_points_list_detach(MountPoint **head, bool *changed) {
 524         MountPoint *m, *n;
 525         int n_failed = 0, k;
 526         struct stat root_st;
 527
 528         assert(head);
 529
 530         k = lstat("/", &root_st);
 531
 532         LIST_FOREACH_SAFE(mount_point, m, n, *head) {
 533                 int r;
 534
 535                 if (k >= 0 &&
 536                     major(root_st.st_dev) != 0 &&
 537                     root_st.st_dev == m->devnum) {
 538                         n_failed ++;
 539                         continue;
 540                 }
 541
 542                 if ((r = delete_dm(m->devnum)) >= 0) {
 543
 544                         if (r > 0 && changed)
 545                                 *changed = true;
 546
 547                         mount_point_free(head, m);
 548                 } else {
 549                         log_warning("Could not delete dm %s: %m", m->path);
 550                         n_failed++;
 551                 }
 552         }
 553
 554         return n_failed;
 555 }
 556
 557 int umount_all(bool *changed) {
 558         int r;
 559         bool umount_changed;
 560
 561         LIST_HEAD(MountPoint, mp_list_head);
 562
 563         LIST_HEAD_INIT(MountPoint, mp_list_head);
 564
 565         r = mount_points_list_get(&mp_list_head);
 566         if (r < 0)
 567                 goto end;
 568
 569         /* retry umount, until nothing can be umounted anymore */
 570         do {
 571                 umount_changed = false;
 572
 573                 mount_points_list_umount(&mp_list_head, &umount_changed, false);
 574                 if (umount_changed)
 575                         *changed = true;
 576
 577         } while (umount_changed);
 578
 579         /* umount one more time with logging enabled */
 580         r = mount_points_list_umount(&mp_list_head, &umount_changed, true);
 581         if (r <= 0)
 582                 goto end;
 583
 584         r = mount_points_list_remount_read_only(&mp_list_head, changed);
 585
 586   end:
 587         mount_points_list_free(&mp_list_head);
 588
 589         return r;
 590 }
 591
 592 int swapoff_all(bool *changed) {
 593         int r;
 594         LIST_HEAD(MountPoint, swap_list_head);
 595
 596         LIST_HEAD_INIT(MountPoint, swap_list_head);
 597
 598         r = swap_list_get(&swap_list_head);
 599         if (r < 0)
 600                 goto end;
 601
 602         r = swap_points_list_off(&swap_list_head, changed);
 603
 604   end:
 605         mount_points_list_free(&swap_list_head);
 606
 607         return r;
 608 }
 609
 610 int loopback_detach_all(bool *changed) {
 611         int r;
 612         LIST_HEAD(MountPoint, loopback_list_head);
 613
 614         LIST_HEAD_INIT(MountPoint, loopback_list_head);
 615
 616         r = loopback_list_get(&loopback_list_head);
 617         if (r < 0)
 618                 goto end;
 619
 620         r = loopback_points_list_detach(&loopback_list_head, changed);
 621
 622   end:
 623         mount_points_list_free(&loopback_list_head);
 624
 625         return r;
 626 }
 627
 628 int dm_detach_all(bool *changed) {
 629         int r;
 630         LIST_HEAD(MountPoint, dm_list_head);
 631
 632         LIST_HEAD_INIT(MountPoint, dm_list_head);
 633
 634         r = dm_list_get(&dm_list_head);
 635         if (r < 0)
 636                 goto end;
 637
 638         r = dm_points_list_detach(&dm_list_head, changed);
 639
 640   end:
 641         mount_points_list_free(&dm_list_head);
 642
 643         return r;
 644 }