sys-utils/losetup.c

   1 /*
   2  * Copyright (C) 2011 Karel Zak <kzak@redhat.com>
   3  * Originally from Ted's losetup.c
   4  *
   5  * losetup.c - setup and control loop devices
   6  */
   7 #include <assert.h>
   8 #include <stdio.h>
   9 #include <string.h>
  10 #include <errno.h>
  11 #include <stdlib.h>
  12 #include <unistd.h>
  13 #include <sys/ioctl.h>
  14 #include <sys/stat.h>
  15 #include <inttypes.h>
  16 #include <getopt.h>
  17
  18 #include <libsmartcols.h>
  19
  20 #include "c.h"
  21 #include "nls.h"
  22 #include "strutils.h"
  23 #include "loopdev.h"
  24 #include "closestream.h"
  25 #include "optutils.h"
  26 #include "xalloc.h"
  27 #include "canonicalize.h"
  28
  29 enum {
  30         A_CREATE = 1,           /* setup a new device */
  31         A_DELETE,               /* delete given device(s) */
  32         A_DELETE_ALL,           /* delete all devices */
  33         A_SHOW,                 /* list devices */
  34         A_SHOW_ONE,             /* print info about one device */
  35         A_FIND_FREE,            /* find first unused */
  36         A_SET_CAPACITY,         /* set device capacity */
  37 };
  38
  39 enum {
  40         COL_NAME = 0,
  41         COL_AUTOCLR,
  42         COL_BACK_FILE,
  43         COL_BACK_INO,
  44         COL_BACK_MAJMIN,
  45         COL_MAJMIN,
  46         COL_OFFSET,
  47         COL_PARTSCAN,
  48         COL_RO,
  49         COL_SIZELIMIT,
  50 };
  51
  52 /* basic output flags */
  53 static int no_headings;
  54 static int raw;
  55
  56 struct colinfo {
  57         const char *name;
  58         double whint;
  59         int flags;
  60         const char *help;
  61 };
  62
  63 static struct colinfo infos[] = {
  64         [COL_AUTOCLR]     = { "AUTOCLEAR",    1, SCOLS_FL_RIGHT, N_("autoclear flag set")},
  65         [COL_BACK_FILE]   = { "BACK-FILE",  0.3, 0, N_("device backing file")},
  66         [COL_BACK_INO]    = { "BACK-INO",     4, SCOLS_FL_RIGHT, N_("backing file inode number")},
  67         [COL_BACK_MAJMIN] = { "BACK-MAJ:MIN", 6, 0, N_("backing file major:minor device number")},
  68         [COL_NAME]        = { "NAME",      0.25, 0, N_("loop device name")},
  69         [COL_OFFSET]      = { "OFFSET",       5, SCOLS_FL_RIGHT, N_("offset from the beginning")},
  70         [COL_PARTSCAN]    = { "PARTSCAN",     1, SCOLS_FL_RIGHT, N_("partscan flag set")},
  71         [COL_RO]          = { "RO",           1, SCOLS_FL_RIGHT, N_("read-only device")},
  72         [COL_SIZELIMIT]   = { "SIZELIMIT",    5, SCOLS_FL_RIGHT, N_("size limit of the file in bytes")},
  73         [COL_MAJMIN]      = { "MAJ:MIN",      3, 0, N_("loop device major:minor number")},
  74 };
  75
  76 #define NCOLS ARRAY_SIZE(infos)
  77
  78 static int columns[NCOLS] = {-1};
  79 static int ncolumns;
  80 static int verbose;
  81
  82 static int get_column_id(int num)
  83 {
  84         assert(ARRAY_SIZE(columns) == NCOLS);
  85         assert(num < ncolumns);
  86         assert(columns[num] < (int) NCOLS);
  87         return columns[num];
  88 }
  89
  90 static struct colinfo *get_column_info(int num)
  91 {
  92         return &infos[ get_column_id(num) ];
  93 }
  94
  95 static int column_name_to_id(const char *name, size_t namesz)
  96 {
  97         size_t i;
  98
  99         for (i = 0; i < NCOLS; i++) {
 100                 const char *cn = infos[i].name;
 101
 102                 if (!strncasecmp(name, cn, namesz) && !*(cn + namesz))
 103                         return i;
 104         }
 105         warnx(_("unknown column: %s"), name);
 106         return -1;
 107 }
 108
 109 static int printf_loopdev(struct loopdev_cxt *lc)
 110 {
 111         uint64_t x;
 112         dev_t dev = 0;
 113         ino_t ino = 0;
 114         char *fname = NULL;
 115         uint32_t type;
 116
 117         fname = loopcxt_get_backing_file(lc);
 118         if (!fname)
 119                 return -EINVAL;
 120
 121         if (loopcxt_get_backing_devno(lc, &dev) == 0)
 122                 loopcxt_get_backing_inode(lc, &ino);
 123
 124         if (!dev && !ino) {
 125                 /*
 126                  * Probably non-root user (no permissions to
 127                  * call LOOP_GET_STATUS ioctls).
 128                  */
 129                 printf("%s: []: (%s)",
 130                         loopcxt_get_device(lc), fname);
 131
 132                 if (loopcxt_get_offset(lc, &x) == 0 && x)
 133                                 printf(_(", offset %ju"), x);
 134
 135                 if (loopcxt_get_sizelimit(lc, &x) == 0 && x)
 136                                 printf(_(", sizelimit %ju"), x);
 137                 printf("\n");
 138                 return 0;
 139         }
 140
 141         printf("%s: [%04d]:%" PRIu64 " (%s)",
 142                 loopcxt_get_device(lc), (int) dev, ino, fname);
 143
 144         if (loopcxt_get_offset(lc, &x) == 0 && x)
 145                         printf(_(", offset %ju"), x);
 146
 147         if (loopcxt_get_sizelimit(lc, &x) == 0 && x)
 148                         printf(_(", sizelimit %ju"), x);
 149
 150         if (loopcxt_get_encrypt_type(lc, &type) == 0) {
 151                 const char *e = loopcxt_get_crypt_name(lc);
 152
 153                 if ((!e || !*e) && type == 1)
 154                         e = "XOR";
 155                 if (e && *e)
 156                         printf(_(", encryption %s (type %u)"), e, type);
 157         }
 158         printf("\n");
 159         return 0;
 160 }
 161
 162 static int show_all_loops(struct loopdev_cxt *lc, const char *file,
 163                           uint64_t offset, int flags)
 164 {
 165         struct stat sbuf, *st = &sbuf;
 166         char *cn_file = NULL;
 167
 168         if (loopcxt_init_iterator(lc, LOOPITER_FL_USED))
 169                 return -1;
 170
 171         if (!file || stat(file, st))
 172                 st = NULL;
 173
 174         while (loopcxt_next(lc) == 0) {
 175                 if (file) {
 176                         int used;
 177                         const char *bf = cn_file ? cn_file : file;
 178
 179                         used = loopcxt_is_used(lc, st, bf, offset, flags);
 180                         if (!used && !cn_file) {
 181                                 bf = cn_file = canonicalize_path(file);
 182                                 used = loopcxt_is_used(lc, st, bf, offset, flags);
 183                         }
 184                         if (!used)
 185                                 continue;
 186                 }
 187                 printf_loopdev(lc);
 188         }
 189         loopcxt_deinit_iterator(lc);
 190         free(cn_file);
 191         return 0;
 192 }
 193
 194 static int delete_loop(struct loopdev_cxt *lc)
 195 {
 196         if (loopcxt_delete_device(lc))
 197                 warn(_("%s: detach failed"), loopcxt_get_device(lc));
 198         else
 199                 return 0;
 200
 201         return -1;
 202 }
 203
 204 static int delete_all_loops(struct loopdev_cxt *lc)
 205 {
 206         int res = 0;
 207
 208         if (loopcxt_init_iterator(lc, LOOPITER_FL_USED))
 209                 return -1;
 210
 211         while (loopcxt_next(lc) == 0)
 212                 res += delete_loop(lc);
 213
 214         loopcxt_deinit_iterator(lc);
 215         return res;
 216 }
 217
 218 static int set_scols_data(struct loopdev_cxt *lc, struct libscols_line *ln)
 219 {
 220         int i;
 221
 222         for (i = 0; i < ncolumns; i++) {
 223                 const char *p = NULL;                   /* external data */
 224                 char *np = NULL;                        /* allocated here */
 225                 uint64_t x = 0;
 226
 227                 switch(get_column_id(i)) {
 228                 case COL_NAME:
 229                         p = loopcxt_get_device(lc);
 230                         break;
 231                 case COL_BACK_FILE:
 232                         p = loopcxt_get_backing_file(lc);
 233                         break;
 234                 case COL_OFFSET:
 235                         if (loopcxt_get_offset(lc, &x) == 0)
 236                                 xasprintf(&np, "%jd", x);
 237                         break;
 238                 case COL_SIZELIMIT:
 239                         if (loopcxt_get_sizelimit(lc, &x) == 0)
 240                                 xasprintf(&np, "%jd", x);
 241                         break;
 242                 case COL_BACK_MAJMIN:
 243                 {
 244                         dev_t dev = 0;
 245                         if (loopcxt_get_backing_devno(lc, &dev) == 0 && dev)
 246                                 xasprintf(&np, "%8u:%-3u", major(dev), minor(dev));
 247                         break;
 248                 }
 249                 case COL_MAJMIN:
 250                 {
 251                         struct stat st;
 252
 253                         if (loopcxt_get_device(lc)
 254                             && stat(loopcxt_get_device(lc), &st) == 0
 255                             && S_ISBLK(st.st_mode)
 256                             && major(st.st_rdev) == LOOPDEV_MAJOR)
 257                                 xasprintf(&np, "%3u:%-3u", major(st.st_rdev),
 258                                                            minor(st.st_rdev));
 259                         break;
 260                 }
 261                 case COL_BACK_INO:
 262                 {
 263                         ino_t ino = 0;
 264                         if (loopcxt_get_backing_inode(lc, &ino) == 0 && ino)
 265                                 xasprintf(&np, "%ju", ino);
 266                         break;
 267                 }
 268                 case COL_AUTOCLR:
 269                         p = loopcxt_is_autoclear(lc) ? "1" : "0";
 270                         break;
 271                 case COL_RO:
 272                         p = loopcxt_is_readonly(lc) ? "1" : "0";
 273                         break;
 274                 case COL_PARTSCAN:
 275                         p = loopcxt_is_partscan(lc) ? "1" : "0";
 276                         break;
 277                 default:
 278                         return -EINVAL;
 279                 }
 280
 281
 282                 if (p)
 283                         scols_line_set_data(ln, i, p);          /* calls strdup() */
 284                 else if (np)
 285                         scols_line_refer_data(ln, i, np);       /* only refers */
 286         }
 287
 288         return 0;
 289 }
 290
 291 static int show_table(struct loopdev_cxt *lc,
 292                       const char *file,
 293                       uint64_t offset,
 294                       int flags)
 295 {
 296         struct stat sbuf, *st = &sbuf;
 297         struct libscols_table *tb;
 298         struct libscols_line *ln;
 299         int i, rc = 0;
 300
 301         if (!(tb = scols_new_table()))
 302                 err(EXIT_FAILURE, _("failed to initialize output table"));
 303         scols_table_enable_raw(tb, raw);
 304         scols_table_enable_noheadings(tb, no_headings);
 305
 306         for (i = 0; i < ncolumns; i++) {
 307                 struct colinfo *ci = get_column_info(i);
 308
 309                 if (!scols_table_new_column(tb, ci->name, ci->whint, ci->flags))
 310                         err(EXIT_FAILURE, _("failed to initialize output column"));
 311         }
 312
 313         /* only one loopdev requested (already assigned to loopdev_cxt) */
 314         if (loopcxt_get_device(lc)) {
 315                 ln = scols_table_new_line(tb, NULL);
 316                 if (!ln)
 317                         err(EXIT_FAILURE, _("failed to initialize output line"));
 318                 rc = set_scols_data(lc, ln);
 319
 320         /* list all loopdevs */
 321         } else {
 322                 char *cn_file = NULL;
 323
 324                 rc = loopcxt_init_iterator(lc, LOOPITER_FL_USED);
 325                 if (rc)
 326                         goto done;
 327                 if (!file || stat(file, st))
 328                         st = NULL;
 329
 330                 while (loopcxt_next(lc) == 0) {
 331                         if (file) {
 332                                 int used;
 333                                 const char *bf = cn_file ? cn_file : file;
 334
 335                                 used = loopcxt_is_used(lc, st, bf, offset, flags);
 336                                 if (!used && !cn_file) {
 337                                         bf = cn_file = canonicalize_path(file);
 338                                         used = loopcxt_is_used(lc, st, bf, offset, flags);
 339                                 }
 340                                 if (!used)
 341                                         continue;
 342                         }
 343
 344                         ln = scols_table_new_line(tb, NULL);
 345                         if (!ln)
 346                                 err(EXIT_FAILURE, _("failed to initialize output column"));
 347                         rc = set_scols_data(lc, ln);
 348                         if (rc)
 349                                 break;
 350                 }
 351
 352                 loopcxt_deinit_iterator(lc);
 353                 free(cn_file);
 354         }
 355 done:
 356         if (rc == 0)
 357                 rc = scols_print_table(tb);
 358         scols_unref_table(tb);
 359         return rc;
 360 }
 361
 362 static void usage(FILE *out)
 363 {
 364         size_t i;
 365
 366         fputs(USAGE_HEADER, out);
 367
 368         fprintf(out,
 369               _(" %1$s [options] [<loopdev>]\n"
 370                 " %1$s [options] -f | <loopdev> <file>\n"),
 371                 program_invocation_short_name);
 372
 373         fputs(USAGE_OPTIONS, out);
 374         fputs(_(" -a, --all                     list all used devices\n"), out);
 375         fputs(_(" -d, --detach <loopdev> [...]  detach one or more devices\n"), out);
 376         fputs(_(" -D, --detach-all              detach all used devices\n"), out);
 377         fputs(_(" -f, --find                    find first unused device\n"), out);
 378         fputs(_(" -c, --set-capacity <loopdev>  resize device\n"), out);
 379         fputs(_(" -j, --associated <file>       list all devices associated with <file>\n"), out);
 380
 381         fputs(USAGE_SEPARATOR, out);
 382
 383         fputs(_(" -o, --offset <num>            start at offset <num> into file\n"), out);
 384         fputs(_("     --sizelimit <num>         device limited to <num> bytes of the file\n"), out);
 385         fputs(_(" -P, --partscan                create partitioned loop device\n"), out);
 386         fputs(_(" -r, --read-only               setup read-only loop device\n"), out);
 387         fputs(_("     --show                    print device name after setup (with -f)\n"), out);
 388         fputs(_(" -v, --verbose                 verbose mode\n"), out);
 389
 390         fputs(USAGE_SEPARATOR, out);
 391
 392         fputs(_(" -l, --list                    list info about all or specified (default)\n"), out);
 393         fputs(_(" -O, --output <cols>           specify columns to output for --list\n"), out);
 394         fputs(_(" -n, --noheadings              don't print headings for --list output\n"), out);
 395         fputs(_("     --raw                     use raw --list output format\n"), out);
 396
 397         fputs(USAGE_SEPARATOR, out);
 398         fputs(USAGE_HELP, out);
 399         fputs(USAGE_VERSION, out);
 400
 401         fputs(_("\nAvailable --list columns:\n"), out);
 402         for (i = 0; i < NCOLS; i++)
 403                 fprintf(out, " %12s  %s\n", infos[i].name, _(infos[i].help));
 404
 405         fprintf(out, USAGE_MAN_TAIL("losetup(8)"));
 406
 407         exit(out == stderr ? EXIT_FAILURE : EXIT_SUCCESS);
 408 }
 409
 410 static void warn_size(const char *filename, uint64_t size)
 411 {
 412         struct stat st;
 413
 414         if (!size) {
 415                 if (stat(filename, &st) || S_ISBLK(st.st_mode))
 416                         return;
 417                 size = st.st_size;
 418         }
 419
 420         if (size < 512)
 421                 warnx(_("%s: Warning: file is smaller than 512 bytes; the loop device "
 422                         "may be useless or invisible for system tools."),
 423                         filename);
 424         else if (size % 512)
 425                 warnx(_("%s: Warning: file does not fit into a 512-byte sector; "
 426                         "the end of the file will be ignored."),
 427                         filename);
 428 }
 429
 430 int main(int argc, char **argv)
 431 {
 432         struct loopdev_cxt lc;
 433         int act = 0, flags = 0, c;
 434         char *file = NULL;
 435         uint64_t offset = 0, sizelimit = 0;
 436         int res = 0, showdev = 0, lo_flags = 0;
 437         char *outarg = NULL;
 438         int list = 0;
 439
 440         enum {
 441                 OPT_SIZELIMIT = CHAR_MAX + 1,
 442                 OPT_SHOW,
 443                 OPT_RAW
 444         };
 445         static const struct option longopts[] = {
 446                 { "all", 0, 0, 'a' },
 447                 { "set-capacity", 1, 0, 'c' },
 448                 { "detach", 1, 0, 'd' },
 449                 { "detach-all", 0, 0, 'D' },
 450                 { "find", 0, 0, 'f' },
 451                 { "help", 0, 0, 'h' },
 452                 { "associated", 1, 0, 'j' },
 453                 { "list", 0, 0, 'l' },
 454                 { "noheadings", 0, 0, 'n' },
 455                 { "offset", 1, 0, 'o' },
 456                 { "output", 1, 0, 'O' },
 457                 { "sizelimit", 1, 0, OPT_SIZELIMIT },
 458                 { "partscan", 0, 0, 'P' },
 459                 { "read-only", 0, 0, 'r' },
 460                 { "raw", 0, 0, OPT_RAW },
 461                 { "show", 0, 0, OPT_SHOW },
 462                 { "verbose", 0, 0, 'v' },
 463                 { "version", 0, 0, 'V' },
 464                 { NULL, 0, 0, 0 }
 465         };
 466
 467         static const ul_excl_t excl[] = {       /* rows and cols in ASCII order */
 468                 { 'D','a','c','d','f','j' },
 469                 { 'D','c','d','f','l' },
 470                 { 'D','c','d','f','O' },
 471                 { 0 }
 472         };
 473         int excl_st[ARRAY_SIZE(excl)] = UL_EXCL_STATUS_INIT;
 474
 475         setlocale(LC_ALL, "");
 476         bindtextdomain(PACKAGE, LOCALEDIR);
 477         textdomain(PACKAGE);
 478         atexit(close_stdout);
 479
 480         if (loopcxt_init(&lc, 0))
 481                 err(EXIT_FAILURE, _("failed to initialize loopcxt"));
 482
 483         while ((c = getopt_long(argc, argv, "ac:d:Dfhj:lno:O:PrvV",
 484                                 longopts, NULL)) != -1) {
 485
 486                 err_exclusive_options(c, longopts, excl, excl_st);
 487
 488                 switch (c) {
 489                 case 'a':
 490                         act = A_SHOW;
 491                         break;
 492                 case 'c':
 493                         act = A_SET_CAPACITY;
 494                         if (!is_loopdev(optarg) ||
 495                             loopcxt_set_device(&lc, optarg))
 496                                 err(EXIT_FAILURE, _("%s: failed to use device"),
 497                                                 optarg);
 498                         break;
 499                 case 'r':
 500                         lo_flags |= LO_FLAGS_READ_ONLY;
 501                         break;
 502                 case 'd':
 503                         act = A_DELETE;
 504                         if (!is_loopdev(optarg) ||
 505                             loopcxt_set_device(&lc, optarg))
 506                                 err(EXIT_FAILURE, _("%s: failed to use device"),
 507                                                 optarg);
 508                         break;
 509                 case 'D':
 510                         act = A_DELETE_ALL;
 511                         break;
 512                 case 'f':
 513                         act = A_FIND_FREE;
 514                         break;
 515                 case 'h':
 516                         usage(stdout);
 517                         break;
 518                 case 'j':
 519                         act = A_SHOW;
 520                         file = optarg;
 521                         break;
 522                 case 'l':
 523                         list = 1;
 524                         break;
 525                 case 'n':
 526                         no_headings = 1;
 527                         break;
 528                 case OPT_RAW:
 529                         raw = 1;
 530                         break;
 531                 case 'o':
 532                         offset = strtosize_or_err(optarg, _("failed to parse offset"));
 533                         flags |= LOOPDEV_FL_OFFSET;
 534                         break;
 535                 case 'O':
 536                         outarg = optarg;
 537                         list = 1;
 538                         break;
 539                 case 'P':
 540                         lo_flags |= LO_FLAGS_PARTSCAN;
 541                         break;
 542                 case OPT_SHOW:
 543                         showdev = 1;
 544                         break;
 545                 case 'v':
 546                         verbose = 1;
 547                         break;
 548                 case 'V':
 549                         printf(UTIL_LINUX_VERSION);
 550                         return EXIT_SUCCESS;
 551                 case OPT_SIZELIMIT:                     /* --sizelimit */
 552                         sizelimit = strtosize_or_err(optarg, _("failed to parse size"));
 553                         flags |= LOOPDEV_FL_SIZELIMIT;
 554                         break;
 555                 default:
 556                         usage(stderr);
 557                 }
 558         }
 559
 560         /* default is --list --all */
 561         if (argc == 1) {
 562                 act = A_SHOW;
 563                 list = 1;
 564         }
 565
 566         /* default --list output columns */
 567         if (list && !ncolumns) {
 568                 columns[ncolumns++] = COL_NAME;
 569                 columns[ncolumns++] = COL_SIZELIMIT;
 570                 columns[ncolumns++] = COL_OFFSET;
 571                 columns[ncolumns++] = COL_AUTOCLR;
 572                 columns[ncolumns++] = COL_RO;
 573                 columns[ncolumns++] = COL_BACK_FILE;
 574         }
 575
 576         if (act == A_FIND_FREE && optind < argc) {
 577                 /*
 578                  * losetup -f <backing_file>
 579                  */
 580                 act = A_CREATE;
 581                 file = argv[optind++];
 582         }
 583
 584         if (list && !act && optind == argc)
 585                 /*
 586                  * losetup --list       defaults to --all
 587                  */
 588                 act = A_SHOW;
 589
 590         if (!act && optind + 1 == argc) {
 591                 /*
 592                  * losetup [--list] <device>
 593                  */
 594                 act = A_SHOW_ONE;
 595                 if (!is_loopdev(argv[optind]) ||
 596                     loopcxt_set_device(&lc, argv[optind]))
 597                         err(EXIT_FAILURE, _("%s: failed to use device"),
 598                                         argv[optind]);
 599                 optind++;
 600         }
 601         if (!act) {
 602                 /*
 603                  * losetup <loopdev> <backing_file>
 604                  */
 605                 act = A_CREATE;
 606
 607                 if (optind >= argc)
 608                         errx(EXIT_FAILURE, _("no loop device specified"));
 609                 /* don't use is_loopdev() here, the device does not have exist yet */
 610                 if (loopcxt_set_device(&lc, argv[optind]))
 611                         err(EXIT_FAILURE, _("%s: failed to use device"),
 612                                         argv[optind]);
 613                 optind++;
 614
 615                 if (optind >= argc)
 616                         errx(EXIT_FAILURE, _("no file specified"));
 617                 file = argv[optind++];
 618         }
 619
 620         if (act != A_CREATE &&
 621             (sizelimit || lo_flags || showdev))
 622                 errx(EXIT_FAILURE,
 623                         _("the options %s are allowed during loop device setup only"),
 624                         "--{sizelimit,read-only,show}");
 625
 626         if ((flags & LOOPDEV_FL_OFFSET) &&
 627             act != A_CREATE && (act != A_SHOW || !file))
 628                 errx(EXIT_FAILURE, _("the option --offset is not allowed in this context"));
 629
 630         if (outarg && string_add_to_idarray(outarg, columns, ARRAY_SIZE(columns),
 631                                          &ncolumns, column_name_to_id) < 0)
 632                 return EXIT_FAILURE;
 633
 634         switch (act) {
 635         case A_CREATE:
 636         {
 637                 int hasdev = loopcxt_has_device(&lc);
 638
 639                 if (hasdev && !is_loopdev(loopcxt_get_device(&lc)))
 640                         loopcxt_add_device(&lc);
 641                 do {
 642                         const char *errpre;
 643
 644                         /* Note that loopcxt_{find_unused,set_device}() resets
 645                          * loopcxt struct.
 646                          */
 647                         if (!hasdev && (res = loopcxt_find_unused(&lc))) {
 648                                 warnx(_("cannot find an unused loop device"));
 649                                 break;
 650                         }
 651                         if (flags & LOOPDEV_FL_OFFSET)
 652                                 loopcxt_set_offset(&lc, offset);
 653                         if (flags & LOOPDEV_FL_SIZELIMIT)
 654                                 loopcxt_set_sizelimit(&lc, sizelimit);
 655                         if (lo_flags)
 656                                 loopcxt_set_flags(&lc, lo_flags);
 657                         if ((res = loopcxt_set_backing_file(&lc, file))) {
 658                                 warn(_("%s: failed to use backing file"), file);
 659                                 break;
 660                         }
 661                         errno = 0;
 662                         res = loopcxt_setup_device(&lc);
 663                         if (res == 0)
 664                                 break;                  /* success */
 665                         if (errno == EBUSY)
 666                                 continue;
 667
 668                         /* errors */
 669                         errpre = hasdev && loopcxt_get_fd(&lc) < 0 ?
 670                                          loopcxt_get_device(&lc) : file;
 671                         warn(_("%s: failed to set up loop device"), errpre);
 672                         break;
 673                 } while (hasdev == 0);
 674
 675                 if (res == 0) {
 676                         if (showdev)
 677                                 printf("%s\n", loopcxt_get_device(&lc));
 678                         warn_size(file, sizelimit);
 679                 }
 680                 break;
 681         }
 682         case A_DELETE:
 683                 res = delete_loop(&lc);
 684                 while (optind < argc) {
 685                         if (!is_loopdev(argv[optind]) ||
 686                             loopcxt_set_device(&lc, argv[optind]))
 687                                 warn(_("%s: failed to use device"),
 688                                                 argv[optind]);
 689                         optind++;
 690                         res += delete_loop(&lc);
 691                 }
 692                 break;
 693         case A_DELETE_ALL:
 694                 res = delete_all_loops(&lc);
 695                 break;
 696         case A_FIND_FREE:
 697                 if (loopcxt_find_unused(&lc))
 698                         warn(_("cannot find an unused loop device"));
 699                 else
 700                         printf("%s\n", loopcxt_get_device(&lc));
 701                 break;
 702         case A_SHOW:
 703                 if (list)
 704                         res = show_table(&lc, file, offset, flags);
 705                 else
 706                         res = show_all_loops(&lc, file, offset, flags);
 707                 break;
 708         case A_SHOW_ONE:
 709                 if (list)
 710                         res = show_table(&lc, NULL, 0, 0);
 711                 else
 712                         res = printf_loopdev(&lc);
 713                 if (res)
 714                         warn("%s", loopcxt_get_device(&lc));
 715                 break;
 716         case A_SET_CAPACITY:
 717                 res = loopcxt_set_capacity(&lc);
 718                 if (res)
 719                         warn(_("%s: set capacity failed"),
 720                                 loopcxt_get_device(&lc));
 721                 break;
 722         default:
 723                 usage(stderr);
 724                 break;
 725         }
 726
 727         loopcxt_deinit(&lc);
 728         return res ? EXIT_FAILURE : EXIT_SUCCESS;
 729 }
 730