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 General Public License as published by
  10   the Free Software Foundation; either version 2 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   General Public License for more details.
  17
  18   You should have received a copy of the GNU 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 (streq(m->path, "/")) {
 414                         n_failed++;
 415                         continue;
 416                 }
 417
 418                 /* Trying to umount. Forcing to umount if busy (only for NFS mounts) */
 419                 if (umount2(m->path, MNT_FORCE) == 0) {
 420                         log_info("Unmounted %s.", m->path);
 421                         if (changed)
 422                                 *changed = true;
 423
 424                         mount_point_free(head, m);
 425                 } else if (log_error) {
 426                         log_warning("Could not unmount %s: %m", m->path);
 427                         n_failed++;
 428                 }
 429         }
 430
 431         return n_failed;
 432 }
 433
 434 static int mount_points_list_remount_read_only(MountPoint **head, bool *changed) {
 435         MountPoint *m, *n;
 436         int n_failed = 0;
 437
 438         assert(head);
 439
 440         LIST_FOREACH_SAFE(mount_point, m, n, *head) {
 441
 442                 if (m->skip_ro) {
 443                         n_failed++;
 444                         continue;
 445                 }
 446
 447                 /* Trying to remount read-only */
 448                 if (mount(NULL, m->path, NULL, MS_MGC_VAL|MS_REMOUNT|MS_RDONLY, NULL) == 0) {
 449                         if (changed)
 450                                 *changed = true;
 451
 452                         mount_point_free(head, m);
 453                 } else {
 454                         log_warning("Could not remount as read-only %s: %m", m->path);
 455                         n_failed++;
 456                 }
 457         }
 458
 459         return n_failed;
 460 }
 461
 462 static int swap_points_list_off(MountPoint **head, bool *changed) {
 463         MountPoint *m, *n;
 464         int n_failed = 0;
 465
 466         assert(head);
 467
 468         LIST_FOREACH_SAFE(mount_point, m, n, *head) {
 469                 if (swapoff(m->path) == 0) {
 470                         if (changed)
 471                                 *changed = true;
 472
 473                         mount_point_free(head, m);
 474                 } else {
 475                         log_warning("Could not deactivate swap %s: %m", m->path);
 476                         n_failed++;
 477                 }
 478         }
 479
 480         return n_failed;
 481 }
 482
 483 static int loopback_points_list_detach(MountPoint **head, bool *changed) {
 484         MountPoint *m, *n;
 485         int n_failed = 0, k;
 486         struct stat root_st;
 487
 488         assert(head);
 489
 490         k = lstat("/", &root_st);
 491
 492         LIST_FOREACH_SAFE(mount_point, m, n, *head) {
 493                 int r;
 494                 struct stat loopback_st;
 495
 496                 if (k >= 0 &&
 497                     major(root_st.st_dev) != 0 &&
 498                     lstat(m->path, &loopback_st) >= 0 &&
 499                     root_st.st_dev == loopback_st.st_rdev) {
 500                         n_failed ++;
 501                         continue;
 502                 }
 503
 504                 if ((r = delete_loopback(m->path)) >= 0) {
 505
 506                         if (r > 0 && changed)
 507                                 *changed = true;
 508
 509                         mount_point_free(head, m);
 510                 } else {
 511                         log_warning("Could not delete loopback %s: %m", m->path);
 512                         n_failed++;
 513                 }
 514         }
 515
 516         return n_failed;
 517 }
 518
 519 static int dm_points_list_detach(MountPoint **head, bool *changed) {
 520         MountPoint *m, *n;
 521         int n_failed = 0, k;
 522         struct stat root_st;
 523
 524         assert(head);
 525
 526         k = lstat("/", &root_st);
 527
 528         LIST_FOREACH_SAFE(mount_point, m, n, *head) {
 529                 int r;
 530
 531                 if (k >= 0 &&
 532                     major(root_st.st_dev) != 0 &&
 533                     root_st.st_dev == m->devnum) {
 534                         n_failed ++;
 535                         continue;
 536                 }
 537
 538                 if ((r = delete_dm(m->devnum)) >= 0) {
 539
 540                         if (r > 0 && changed)
 541                                 *changed = true;
 542
 543                         mount_point_free(head, m);
 544                 } else {
 545                         log_warning("Could not delete dm %s: %m", m->path);
 546                         n_failed++;
 547                 }
 548         }
 549
 550         return n_failed;
 551 }
 552
 553 int umount_all(bool *changed) {
 554         int r;
 555         bool umount_changed;
 556
 557         LIST_HEAD(MountPoint, mp_list_head);
 558
 559         LIST_HEAD_INIT(MountPoint, mp_list_head);
 560
 561         r = mount_points_list_get(&mp_list_head);
 562         if (r < 0)
 563                 goto end;
 564
 565         /* retry umount, until nothing can be umounted anymore */
 566         do {
 567                 umount_changed = false;
 568                 r = mount_points_list_umount(&mp_list_head, &umount_changed, false);
 569                 if (umount_changed)
 570                         *changed = true;
 571         } while(umount_changed);
 572         /* umount one more time with logging enabled */
 573         r = mount_points_list_umount(&mp_list_head, &umount_changed, true);
 574         if (r <= 0)
 575                 goto end;
 576
 577         r = mount_points_list_remount_read_only(&mp_list_head, changed);
 578
 579   end:
 580         mount_points_list_free(&mp_list_head);
 581
 582         return r;
 583 }
 584
 585 int swapoff_all(bool *changed) {
 586         int r;
 587         LIST_HEAD(MountPoint, swap_list_head);
 588
 589         LIST_HEAD_INIT(MountPoint, swap_list_head);
 590
 591         r = swap_list_get(&swap_list_head);
 592         if (r < 0)
 593                 goto end;
 594
 595         r = swap_points_list_off(&swap_list_head, changed);
 596
 597   end:
 598         mount_points_list_free(&swap_list_head);
 599
 600         return r;
 601 }
 602
 603 int loopback_detach_all(bool *changed) {
 604         int r;
 605         LIST_HEAD(MountPoint, loopback_list_head);
 606
 607         LIST_HEAD_INIT(MountPoint, loopback_list_head);
 608
 609         r = loopback_list_get(&loopback_list_head);
 610         if (r < 0)
 611                 goto end;
 612
 613         r = loopback_points_list_detach(&loopback_list_head, changed);
 614
 615   end:
 616         mount_points_list_free(&loopback_list_head);
 617
 618         return r;
 619 }
 620
 621 int dm_detach_all(bool *changed) {
 622         int r;
 623         LIST_HEAD(MountPoint, dm_list_head);
 624
 625         LIST_HEAD_INIT(MountPoint, dm_list_head);
 626
 627         r = dm_list_get(&dm_list_head);
 628         if (r < 0)
 629                 goto end;
 630
 631         r = dm_points_list_detach(&dm_list_head, changed);
 632
 633   end:
 634         mount_points_list_free(&dm_list_head);
 635
 636         return r;
 637 }