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