lib/libdevmapper.c

   1 #include <sys/ioctl.h>
   2 #include <sys/stat.h>
   3 #include <stdio.h>
   4 #include <dirent.h>
   5 #include <errno.h>
   6 #include <libdevmapper.h>
   7 #include <fcntl.h>
   8 #include <linux/fs.h>
   9 #include <uuid/uuid.h>
  10
  11 #include "internal.h"
  12 #include "luks.h"
  13
  14 #define DEVICE_DIR              "/dev"
  15 #define DM_UUID_LEN             129
  16 #define DM_UUID_PREFIX          "CRYPT-"
  17 #define DM_UUID_PREFIX_LEN      6
  18 #define DM_CRYPT_TARGET         "crypt"
  19 #define RETRY_COUNT             5
  20
  21 /* Set if dm-crypt version was probed */
  22 static int _dm_crypt_checked = 0;
  23 static uint32_t _dm_crypt_flags = 0;
  24
  25 static int _dm_use_count = 0;
  26 static struct crypt_device *_context = NULL;
  27
  28 /* Check if we have DM flag to instruct kernel to force wipe buffers */
  29 #if !HAVE_DECL_DM_TASK_SECURE_DATA
  30 static int dm_task_secure_data(struct dm_task *dmt) { return 1; }
  31 #endif
  32
  33 /* Compatibility for old device-mapper without udev support */
  34 #if HAVE_DECL_DM_UDEV_DISABLE_DISK_RULES_FLAG
  35 #define CRYPT_TEMP_UDEV_FLAGS   DM_UDEV_DISABLE_SUBSYSTEM_RULES_FLAG | \
  36                                 DM_UDEV_DISABLE_DISK_RULES_FLAG | \
  37                                 DM_UDEV_DISABLE_OTHER_RULES_FLAG
  38 #define _dm_task_set_cookie     dm_task_set_cookie
  39 #define _dm_udev_wait           dm_udev_wait
  40 #else
  41 #define CRYPT_TEMP_UDEV_FLAGS   0
  42 static int _dm_task_set_cookie(struct dm_task *dmt, uint32_t *cookie, uint16_t flags) { return 0; }
  43 static int _dm_udev_wait(uint32_t cookie) { return 0; };
  44 #endif
  45
  46 static int _dm_use_udev()
  47 {
  48 #ifdef USE_UDEV /* cannot be enabled if devmapper is too old */
  49         return dm_udev_get_sync_support();
  50 #else
  51         return 0;
  52 #endif
  53 }
  54
  55 static void set_dm_error(int level, const char *file, int line,
  56                          const char *f, ...)
  57 {
  58         char *msg = NULL;
  59         va_list va;
  60
  61         va_start(va, f);
  62         if (vasprintf(&msg, f, va) > 0) {
  63                 if (level < 4) {
  64                         log_err(_context, msg);
  65                         log_err(_context, "\n");
  66                 } else
  67                         log_dbg(msg);
  68         }
  69         free(msg);
  70         va_end(va);
  71 }
  72
  73 static int _dm_simple(int task, const char *name, int udev_wait);
  74
  75 static void _dm_set_crypt_compat(const char *dm_version, unsigned crypt_maj,
  76                                  unsigned crypt_min, unsigned crypt_patch)
  77 {
  78         unsigned dm_maj, dm_min, dm_patch;
  79
  80         if (sscanf(dm_version, "%u.%u.%u", &dm_maj, &dm_min, &dm_patch) != 3)
  81                 dm_maj = dm_min = dm_patch = 0;
  82
  83         log_dbg("Detected dm-crypt version %i.%i.%i, dm-ioctl version %u.%u.%u.",
  84                 crypt_maj, crypt_min, crypt_patch, dm_maj, dm_min, dm_patch);
  85
  86         if (crypt_maj >= 1 && crypt_min >= 2)
  87                 _dm_crypt_flags |= DM_KEY_WIPE_SUPPORTED;
  88         else
  89                 log_dbg("Suspend and resume disabled, no wipe key support.");
  90
  91         if (crypt_maj >= 1 && crypt_min >= 10)
  92                 _dm_crypt_flags |= DM_LMK_SUPPORTED;
  93
  94         if (dm_maj >= 4 && dm_min >= 20)
  95                 _dm_crypt_flags |= DM_SECURE_SUPPORTED;
  96
  97         /* Repeat test if dm-crypt is not present */
  98         if (crypt_maj > 0)
  99                 _dm_crypt_checked = 1;
 100 }
 101
 102 static int _dm_check_versions(void)
 103 {
 104         struct dm_task *dmt;
 105         struct dm_versions *target, *last_target;
 106         char dm_version[16];
 107
 108         if (_dm_crypt_checked)
 109                 return 1;
 110
 111         /* FIXME: add support to DM so it forces crypt target module load here */
 112         if (!(dmt = dm_task_create(DM_DEVICE_LIST_VERSIONS)))
 113                 return 0;
 114
 115         if (!dm_task_run(dmt)) {
 116                 dm_task_destroy(dmt);
 117                 return 0;
 118         }
 119
 120         if (!dm_task_get_driver_version(dmt, dm_version, sizeof(dm_version))) {
 121                 dm_task_destroy(dmt);
 122                 return 0;
 123         }
 124
 125         target = dm_task_get_versions(dmt);
 126         do {
 127                 last_target = target;
 128                 if (!strcmp(DM_CRYPT_TARGET, target->name)) {
 129                         _dm_set_crypt_compat(dm_version,
 130                                              (unsigned)target->version[0],
 131                                              (unsigned)target->version[1],
 132                                              (unsigned)target->version[2]);
 133                 }
 134                 target = (void *) target + target->next;
 135         } while (last_target != target);
 136
 137         dm_task_destroy(dmt);
 138         return 1;
 139 }
 140
 141 uint32_t dm_flags(void)
 142 {
 143         if (!_dm_crypt_checked)
 144                 _dm_check_versions();
 145
 146         return _dm_crypt_flags;
 147 }
 148
 149 int dm_init(struct crypt_device *context, int check_kernel)
 150 {
 151         if (!_dm_use_count++) {
 152                 log_dbg("Initialising device-mapper backend%s, UDEV is %sabled.",
 153                         check_kernel ? "" : " (NO kernel check requested)",
 154                         _dm_use_udev() ? "en" : "dis");
 155                 if (check_kernel && !_dm_check_versions()) {
 156                         log_err(context, _("Cannot initialize device-mapper. Is dm_mod kernel module loaded?\n"));
 157                         return -1;
 158                 }
 159                 if (getuid() || geteuid())
 160                         log_dbg(("WARNING: Running as a non-root user. Functionality may be unavailable."));
 161                 dm_log_init(set_dm_error);
 162                 dm_log_init_verbose(10);
 163         }
 164
 165         // FIXME: global context is not safe
 166         if (context)
 167                 _context = context;
 168
 169         return 1;       /* unsafe memory */
 170 }
 171
 172 void dm_exit(void)
 173 {
 174         if (_dm_use_count && (!--_dm_use_count)) {
 175                 log_dbg("Releasing device-mapper backend.");
 176                 dm_log_init_verbose(0);
 177                 dm_log_init(NULL);
 178                 dm_lib_release();
 179                 _context = NULL;
 180         }
 181 }
 182
 183 static char *__lookup_dev(char *path, dev_t dev, int dir_level, const int max_level)
 184 {
 185         struct dirent *entry;
 186         struct stat st;
 187         char *ptr;
 188         char *result = NULL;
 189         DIR *dir;
 190         int space;
 191
 192         /* Ignore strange nested directories */
 193         if (dir_level > max_level)
 194                 return NULL;
 195
 196         path[PATH_MAX - 1] = '\0';
 197         ptr = path + strlen(path);
 198         *ptr++ = '/';
 199         *ptr = '\0';
 200         space = PATH_MAX - (ptr - path);
 201
 202         dir = opendir(path);
 203         if (!dir)
 204                 return NULL;
 205
 206         while((entry = readdir(dir))) {
 207                 if (entry->d_name[0] == '.' ||
 208                     !strncmp(entry->d_name, "..", 2))
 209                         continue;
 210
 211                 strncpy(ptr, entry->d_name, space);
 212                 if (stat(path, &st) < 0)
 213                         continue;
 214
 215                 if (S_ISDIR(st.st_mode)) {
 216                         result = __lookup_dev(path, dev, dir_level + 1, max_level);
 217                         if (result)
 218                                 break;
 219                 } else if (S_ISBLK(st.st_mode)) {
 220                         /* workaround: ignore dm-X devices, these are internal kernel names */
 221                         if (dir_level == 0 && !strncmp(entry->d_name, "dm-", 3))
 222                                 continue;
 223                         if (st.st_rdev == dev) {
 224                                 result = strdup(path);
 225                                 break;
 226                         }
 227                 }
 228         }
 229
 230         closedir(dir);
 231         return result;
 232 }
 233
 234 static char *lookup_dev(const char *dev_id)
 235 {
 236         uint32_t major, minor;
 237         dev_t dev;
 238         char *result = NULL, buf[PATH_MAX + 1];
 239
 240         if (sscanf(dev_id, "%" PRIu32 ":%" PRIu32, &major, &minor) != 2)
 241                 return NULL;
 242
 243         dev = makedev(major, minor);
 244         strncpy(buf, DEVICE_DIR, PATH_MAX);
 245         buf[PATH_MAX] = '\0';
 246
 247         /* First try low level device */
 248         if ((result = __lookup_dev(buf, dev, 0, 0)))
 249                 return result;
 250
 251         /* If it is dm, try DM dir  */
 252         if (dm_is_dm_major(major)) {
 253                 strncpy(buf, dm_dir(), PATH_MAX);
 254                 if ((result = __lookup_dev(buf, dev, 0, 0)))
 255                         return result;
 256         }
 257
 258         strncpy(buf, DEVICE_DIR, PATH_MAX);
 259         result = __lookup_dev(buf, dev, 0, 4);
 260
 261         /* If not found, return NULL */
 262         return result;
 263 }
 264
 265 static int _dev_read_ahead(const char *dev, uint32_t *read_ahead)
 266 {
 267         int fd, r = 0;
 268         long read_ahead_long;
 269
 270         if ((fd = open(dev, O_RDONLY)) < 0)
 271                 return 0;
 272
 273         r = ioctl(fd, BLKRAGET, &read_ahead_long) ? 0 : 1;
 274         close(fd);
 275
 276         if (r)
 277                 *read_ahead = (uint32_t) read_ahead_long;
 278
 279         return r;
 280 }
 281
 282 static void hex_key(char *hexkey, size_t key_size, const char *key)
 283 {
 284         int i;
 285
 286         for(i = 0; i < key_size; i++)
 287                 sprintf(&hexkey[i * 2], "%02x", (unsigned char)key[i]);
 288 }
 289
 290 static char *get_params(const char *device, uint64_t skip, uint64_t offset,
 291                         const char *cipher, size_t key_size, const char *key)
 292 {
 293         char *params;
 294         char *hexkey;
 295
 296         hexkey = crypt_safe_alloc(key_size * 2 + 1);
 297         if (!hexkey)
 298                 return NULL;
 299
 300         hex_key(hexkey, key_size, key);
 301
 302         params = crypt_safe_alloc(strlen(hexkey) + strlen(cipher) + strlen(device) + 64);
 303         if (!params)
 304                 goto out;
 305
 306         sprintf(params, "%s %s %" PRIu64 " %s %" PRIu64,
 307                 cipher, hexkey, skip, device, offset);
 308
 309 out:
 310         crypt_safe_free(hexkey);
 311         return params;
 312 }
 313
 314 /* DM helpers */
 315 static int _dm_simple(int task, const char *name, int udev_wait)
 316 {
 317         int r = 0;
 318         struct dm_task *dmt;
 319         uint32_t cookie = 0;
 320
 321         if (!_dm_use_udev())
 322                 udev_wait = 0;
 323
 324         if (!(dmt = dm_task_create(task)))
 325                 return 0;
 326
 327         if (name && !dm_task_set_name(dmt, name))
 328                 goto out;
 329
 330         if (udev_wait && !_dm_task_set_cookie(dmt, &cookie, 0))
 331                 goto out;
 332
 333         r = dm_task_run(dmt);
 334
 335         if (udev_wait)
 336                 (void)_dm_udev_wait(cookie);
 337
 338       out:
 339         dm_task_destroy(dmt);
 340         return r;
 341 }
 342
 343 static int _error_device(const char *name, size_t size)
 344 {
 345         struct dm_task *dmt;
 346         int r = 0;
 347
 348         if (!(dmt = dm_task_create(DM_DEVICE_RELOAD)))
 349                 return 0;
 350
 351         if (!dm_task_set_name(dmt, name))
 352                 goto error;
 353
 354         if (!dm_task_add_target(dmt, UINT64_C(0), size, "error", ""))
 355                 goto error;
 356
 357         if (!dm_task_set_ro(dmt))
 358                 goto error;
 359
 360         if (!dm_task_no_open_count(dmt))
 361                 goto error;
 362
 363         if (!dm_task_run(dmt))
 364                 goto error;
 365
 366         if (!_dm_simple(DM_DEVICE_RESUME, name, 1)) {
 367                 _dm_simple(DM_DEVICE_CLEAR, name, 0);
 368                 goto error;
 369         }
 370
 371         r = 1;
 372
 373 error:
 374         dm_task_destroy(dmt);
 375         return r;
 376 }
 377
 378 int dm_remove_device(const char *name, int force, uint64_t size)
 379 {
 380         int r = -EINVAL;
 381         int retries = force ? RETRY_COUNT : 1;
 382         int error_target = 0;
 383
 384         if (!name || (force && !size))
 385                 return -EINVAL;
 386
 387         do {
 388                 r = _dm_simple(DM_DEVICE_REMOVE, name, 1) ? 0 : -EINVAL;
 389                 if (--retries && r) {
 390                         log_dbg("WARNING: other process locked internal device %s, %s.",
 391                                 name, retries ? "retrying remove" : "giving up");
 392                         if (force && (crypt_get_debug_level() == CRYPT_LOG_DEBUG))
 393                                 debug_processes_using_device(name);
 394                         sleep(1);
 395                         if (force && !error_target) {
 396                                 /* If force flag is set, replace device with error, read-only target.
 397                                  * it should stop processes from reading it and also removed underlying
 398                                  * device from mapping, so it is usable again.
 399                                  * Force flag should be used only for temporary devices, which are
 400                                  * intended to work inside cryptsetup only!
 401                                  * Anyway, if some process try to read temporary cryptsetup device,
 402                                  * it is bug - no other process should try touch it (e.g. udev).
 403                                  */
 404                                 _error_device(name, size);
 405                                 error_target = 1;
 406                         }
 407                 }
 408         } while (r == -EINVAL && retries);
 409
 410         dm_task_update_nodes();
 411
 412         return r;
 413 }
 414
 415 #define UUID_LEN 37 /* 36 + \0, libuuid ... */
 416 /*
 417  * UUID has format: CRYPT-<devicetype>-[<uuid>-]<device name>
 418  * CRYPT-PLAIN-name
 419  * CRYPT-LUKS1-00000000000000000000000000000000-name
 420  * CRYPT-TEMP-name
 421  */
 422 static void dm_prepare_uuid(const char *name, const char *type, const char *uuid, char *buf, size_t buflen)
 423 {
 424         char *ptr, uuid2[UUID_LEN] = {0};
 425         uuid_t uu;
 426         int i = 0;
 427
 428         /* Remove '-' chars */
 429         if (uuid && !uuid_parse(uuid, uu)) {
 430                 for (ptr = uuid2, i = 0; i < UUID_LEN; i++)
 431                         if (uuid[i] != '-') {
 432                                 *ptr = uuid[i];
 433                                 ptr++;
 434                         }
 435         }
 436
 437         i = snprintf(buf, buflen, DM_UUID_PREFIX "%s%s%s%s%s",
 438                 type ?: "", type ? "-" : "",
 439                 uuid2[0] ? uuid2 : "", uuid2[0] ? "-" : "",
 440                 name);
 441
 442         log_dbg("DM-UUID is %s", buf);
 443         if (i >= buflen)
 444                 log_err(NULL, _("DM-UUID for device %s was truncated.\n"), name);
 445 }
 446
 447 int dm_create_device(const char *name,
 448                      const char *device,
 449                      const char *cipher,
 450                      const char *type,
 451                      const char *uuid,
 452                      uint64_t size,
 453                      uint64_t skip,
 454                      uint64_t offset,
 455                      size_t key_size,
 456                      const char *key,
 457                      int read_only,
 458                      int reload)
 459 {
 460         struct dm_task *dmt = NULL;
 461         struct dm_info dmi;
 462         char *params = NULL;
 463         char *error = NULL;
 464         char dev_uuid[DM_UUID_LEN] = {0};
 465         int r = -EINVAL;
 466         uint32_t read_ahead = 0;
 467         uint32_t cookie = 0;
 468         uint16_t udev_flags = 0;
 469
 470         params = get_params(device, skip, offset, cipher, key_size, key);
 471         if (!params)
 472                 goto out_no_removal;
 473
 474         if (type && !strncmp(type, "TEMP", 4))
 475                 udev_flags = CRYPT_TEMP_UDEV_FLAGS;
 476
 477         /* All devices must have DM_UUID, only resize on old device is exception */
 478         if (reload) {
 479                 if (!(dmt = dm_task_create(DM_DEVICE_RELOAD)))
 480                         goto out_no_removal;
 481
 482                 if (!dm_task_set_name(dmt, name))
 483                         goto out_no_removal;
 484         } else {
 485                 dm_prepare_uuid(name, type, uuid, dev_uuid, sizeof(dev_uuid));
 486
 487                 if (!(dmt = dm_task_create(DM_DEVICE_CREATE)))
 488                         goto out_no_removal;
 489
 490                 if (!dm_task_set_name(dmt, name))
 491                         goto out_no_removal;
 492
 493                 if (!dm_task_set_uuid(dmt, dev_uuid))
 494                         goto out_no_removal;
 495
 496                 if (_dm_use_udev() && !_dm_task_set_cookie(dmt, &cookie, udev_flags))
 497                         goto out_no_removal;
 498         }
 499
 500         if ((dm_flags() & DM_SECURE_SUPPORTED) && !dm_task_secure_data(dmt))
 501                 goto out_no_removal;
 502         if (read_only && !dm_task_set_ro(dmt))
 503                 goto out_no_removal;
 504         if (!dm_task_add_target(dmt, 0, size, DM_CRYPT_TARGET, params))
 505                 goto out_no_removal;
 506
 507 #ifdef DM_READ_AHEAD_MINIMUM_FLAG
 508         if (_dev_read_ahead(device, &read_ahead) &&
 509             !dm_task_set_read_ahead(dmt, read_ahead, DM_READ_AHEAD_MINIMUM_FLAG))
 510                 goto out_no_removal;
 511 #endif
 512
 513         if (!dm_task_run(dmt))
 514                 goto out_no_removal;
 515
 516         if (reload) {
 517                 dm_task_destroy(dmt);
 518                 if (!(dmt = dm_task_create(DM_DEVICE_RESUME)))
 519                         goto out;
 520                 if (!dm_task_set_name(dmt, name))
 521                         goto out;
 522                 if (uuid && !dm_task_set_uuid(dmt, dev_uuid))
 523                         goto out;
 524                 if (_dm_use_udev() && !_dm_task_set_cookie(dmt, &cookie, udev_flags))
 525                         goto out;
 526                 if (!dm_task_run(dmt))
 527                         goto out;
 528         }
 529
 530         if (!dm_task_get_info(dmt, &dmi))
 531                 goto out;
 532
 533         r = 0;
 534 out:
 535         if (_dm_use_udev()) {
 536                 (void)_dm_udev_wait(cookie);
 537                 cookie = 0;
 538         }
 539
 540         if (r < 0 && !reload) {
 541                 if (get_error())
 542                         error = strdup(get_error());
 543
 544                 dm_remove_device(name, 0, 0);
 545
 546                 if (error) {
 547                         set_error(error);
 548                         free(error);
 549                 }
 550         }
 551
 552 out_no_removal:
 553         if (cookie && _dm_use_udev())
 554                 (void)_dm_udev_wait(cookie);
 555
 556         if (params)
 557                 crypt_safe_free(params);
 558         if (dmt)
 559                 dm_task_destroy(dmt);
 560
 561         dm_task_update_nodes();
 562         return r;
 563 }
 564
 565 int dm_status_device(const char *name)
 566 {
 567         struct dm_task *dmt;
 568         struct dm_info dmi;
 569         uint64_t start, length;
 570         char *target_type, *params;
 571         void *next = NULL;
 572         int r = -EINVAL;
 573
 574         if (!(dmt = dm_task_create(DM_DEVICE_STATUS)))
 575                 goto out;
 576
 577         if (!dm_task_set_name(dmt, name))
 578                 goto out;
 579
 580         if (!dm_task_run(dmt))
 581                 goto out;
 582
 583         if (!dm_task_get_info(dmt, &dmi))
 584                 goto out;
 585
 586         if (!dmi.exists) {
 587                 r = -ENODEV;
 588                 goto out;
 589         }
 590
 591         next = dm_get_next_target(dmt, next, &start, &length,
 592                                   &target_type, &params);
 593         if (!target_type || strcmp(target_type, DM_CRYPT_TARGET) != 0 ||
 594             start != 0 || next)
 595                 r = -EINVAL;
 596         else
 597                 r = (dmi.open_count > 0);
 598 out:
 599         if (dmt)
 600                 dm_task_destroy(dmt);
 601
 602         return r;
 603 }
 604
 605 int dm_query_device(const char *name,
 606                     char **device,
 607                     uint64_t *size,
 608                     uint64_t *skip,
 609                     uint64_t *offset,
 610                     char **cipher,
 611                     int *key_size,
 612                     char **key,
 613                     int *read_only,
 614                     int *suspended,
 615                     char **uuid)
 616 {
 617         struct dm_task *dmt;
 618         struct dm_info dmi;
 619         uint64_t start, length, val64;
 620         char *target_type, *params, *rcipher, *key_, *rdevice, *endp, buffer[3], *tmp_uuid;
 621         void *next = NULL;
 622         int i, r = -EINVAL;
 623
 624         if (!(dmt = dm_task_create(DM_DEVICE_TABLE)))
 625                 goto out;
 626         if ((dm_flags() & DM_SECURE_SUPPORTED) && !dm_task_secure_data(dmt))
 627                 goto out;
 628         if (!dm_task_set_name(dmt, name))
 629                 goto out;
 630         r = -ENODEV;
 631         if (!dm_task_run(dmt))
 632                 goto out;
 633
 634         r = -EINVAL;
 635         if (!dm_task_get_info(dmt, &dmi))
 636                 goto out;
 637
 638         if (!dmi.exists) {
 639                 r = -ENODEV;
 640                 goto out;
 641         }
 642
 643         next = dm_get_next_target(dmt, next, &start, &length,
 644                                   &target_type, &params);
 645         if (!target_type || strcmp(target_type, DM_CRYPT_TARGET) != 0 ||
 646             start != 0 || next)
 647                 goto out;
 648
 649         if (size)
 650                 *size = length;
 651
 652         rcipher = strsep(&params, " ");
 653         /* cipher */
 654         if (cipher)
 655                 *cipher = strdup(rcipher);
 656
 657         /* skip */
 658         key_ = strsep(&params, " ");
 659         if (!params)
 660                 goto out;
 661         val64 = strtoull(params, &params, 10);
 662         if (*params != ' ')
 663                 goto out;
 664         params++;
 665         if (skip)
 666                 *skip = val64;
 667
 668         /* device */
 669         rdevice = strsep(&params, " ");
 670         if (device)
 671                 *device = lookup_dev(rdevice);
 672
 673         /*offset */
 674         if (!params)
 675                 goto out;
 676         val64 = strtoull(params, &params, 10);
 677         if (*params)
 678                 goto out;
 679         if (offset)
 680                 *offset = val64;
 681
 682         /* key_size */
 683         if (key_size)
 684                 *key_size = strlen(key_) / 2;
 685
 686         /* key */
 687         if (key_size && key) {
 688                 *key = crypt_safe_alloc(*key_size);
 689                 if (!*key) {
 690                         r = -ENOMEM;
 691                         goto out;
 692                 }
 693
 694                 buffer[2] = '\0';
 695                 for(i = 0; i < *key_size; i++) {
 696                         memcpy(buffer, &key_[i * 2], 2);
 697                         (*key)[i] = strtoul(buffer, &endp, 16);
 698                         if (endp != &buffer[2]) {
 699                                 crypt_safe_free(key);
 700                                 *key = NULL;
 701                                 goto out;
 702                         }
 703                 }
 704         }
 705         memset(key_, 0, strlen(key_));
 706
 707         if (read_only)
 708                 *read_only = dmi.read_only;
 709
 710         if (suspended)
 711                 *suspended = dmi.suspended;
 712
 713         if (uuid && (tmp_uuid = (char*)dm_task_get_uuid(dmt)) &&
 714             !strncmp(tmp_uuid, DM_UUID_PREFIX, DM_UUID_PREFIX_LEN))
 715                 *uuid = strdup(tmp_uuid + DM_UUID_PREFIX_LEN);
 716
 717         r = (dmi.open_count > 0);
 718 out:
 719         if (dmt)
 720                 dm_task_destroy(dmt);
 721
 722         return r;
 723 }
 724
 725 static int _dm_message(const char *name, const char *msg)
 726 {
 727         int r = 0;
 728         struct dm_task *dmt;
 729
 730         if (!(dmt = dm_task_create(DM_DEVICE_TARGET_MSG)))
 731                 return 0;
 732
 733         if ((dm_flags() & DM_SECURE_SUPPORTED) && !dm_task_secure_data(dmt))
 734                 goto out;
 735
 736         if (name && !dm_task_set_name(dmt, name))
 737                 goto out;
 738
 739         if (!dm_task_set_sector(dmt, (uint64_t) 0))
 740                 goto out;
 741
 742         if (!dm_task_set_message(dmt, msg))
 743                 goto out;
 744
 745         r = dm_task_run(dmt);
 746
 747       out:
 748         dm_task_destroy(dmt);
 749         return r;
 750 }
 751
 752 int dm_suspend_and_wipe_key(const char *name)
 753 {
 754         if (!_dm_check_versions())
 755                 return -ENOTSUP;
 756
 757         if (!(_dm_crypt_flags & DM_KEY_WIPE_SUPPORTED))
 758                 return -ENOTSUP;
 759
 760         if (!_dm_simple(DM_DEVICE_SUSPEND, name, 0))
 761                 return -EINVAL;
 762
 763         if (!_dm_message(name, "key wipe")) {
 764                 _dm_simple(DM_DEVICE_RESUME, name, 1);
 765                 return -EINVAL;
 766         }
 767
 768         return 0;
 769 }
 770
 771 int dm_resume_and_reinstate_key(const char *name,
 772                                 size_t key_size,
 773                                 const char *key)
 774 {
 775         int msg_size = key_size * 2 + 10; // key set <key>
 776         char *msg;
 777         int r = 0;
 778
 779         if (!_dm_check_versions())
 780                 return -ENOTSUP;
 781
 782         if (!(_dm_crypt_flags & DM_KEY_WIPE_SUPPORTED))
 783                 return -ENOTSUP;
 784
 785         msg = crypt_safe_alloc(msg_size);
 786         if (!msg)
 787                 return -ENOMEM;
 788
 789         memset(msg, 0, msg_size);
 790         strcpy(msg, "key set ");
 791         hex_key(&msg[8], key_size, key);
 792
 793         if (!_dm_message(name, msg) ||
 794             !_dm_simple(DM_DEVICE_RESUME, name, 1))
 795                 r = -EINVAL;
 796
 797         crypt_safe_free(msg);
 798         return r;
 799 }
 800
 801 const char *dm_get_dir(void)
 802 {
 803         return dm_dir();
 804 }