util-linux/losetup.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Mini losetup implementation for busybox
   4  *
   5  * Copyright (C) 2002  Matt Kraai.
   6  *
   7  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
   8  */
   9
  10 //usage:#define losetup_trivial_usage
  11 //usage:       "[-r] [-o OFS] {-f|LOOPDEV} FILE - associate loop devices\n"
  12 //usage:       "        losetup -d LOOPDEV - disassociate\n"
  13 //usage:       "        losetup -a - show status of  all\n"
  14 //usage:       "        losetup -f - show next available"
  15 //usage:#define losetup_full_usage "\n\n"
  16 //usage:       "        -o OFS  Start OFS bytes into FILE"
  17 //usage:     "\n        -r      Read-only"
  18 //usage:     "\n        -f      Show/find first free loop device"
  19 //usage:
  20 //usage:#define losetup_notes_usage
  21 //usage:       "One argument (losetup /dev/loop1) will display the current association\n"
  22 //usage:       "(if any), or disassociate it (with -d). The display shows the offset\n"
  23 //usage:       "and filename of the file the loop device is currently bound to.\n\n"
  24 //usage:       "Two arguments (losetup /dev/loop1 file.img) create a new association,\n"
  25 //usage:       "with an optional offset (-o 12345). Encryption is not yet supported.\n"
  26 //usage:       "losetup -f will show the first loop free loop device\n\n"
  27
  28 #include "libbb.h"
  29
  30 int losetup_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  31 int losetup_main(int argc UNUSED_PARAM, char **argv)
  32 {
  33         unsigned opt;
  34         char *opt_o;
  35         char dev[LOOP_NAMESIZE];
  36         enum {
  37                 OPT_d = (1 << 0),
  38                 OPT_o = (1 << 1),
  39                 OPT_f = (1 << 2),
  40                 OPT_a = (1 << 3),
  41                 OPT_r = (1 << 4), /* must be last */
  42         };
  43
  44         opt_complementary = "?2:d--ofar:a--ofr";
  45         opt = getopt32(argv, "do:far", &opt_o);
  46         argv += optind;
  47
  48         /* LOOPDEV */
  49         if (!opt && argv[0] && !argv[1]) {
  50                 char *s;
  51
  52                 s = query_loop(argv[0]);
  53                 if (!s)
  54                         bb_simple_perror_msg_and_die(argv[0]);
  55                 printf("%s: %s\n", argv[0], s);
  56                 if (ENABLE_FEATURE_CLEAN_UP)
  57                         free(s);
  58                 return EXIT_SUCCESS;
  59         }
  60
  61         /* -d LOOPDEV */
  62         if (opt == OPT_d) {
  63                 if (del_loop(argv[0]))
  64                         bb_simple_perror_msg_and_die(argv[0]);
  65                 return EXIT_SUCCESS;
  66         }
  67
  68         /* -a */
  69         if (opt == OPT_a) {
  70                 int n;
  71                 for (n = 0; n < 10; n++) {
  72                         char *s;
  73
  74                         sprintf(dev, LOOP_FORMAT, n);
  75                         s = query_loop(dev);
  76                         if (s) {
  77                                 printf("%s: %s\n", dev, s);
  78                                 if (ENABLE_FEATURE_CLEAN_UP)
  79                                         free(s);
  80                         }
  81                 }
  82                 return EXIT_SUCCESS;
  83         }
  84
  85         /* contains -f */
  86         if (opt & OPT_f) {
  87                 char *s;
  88                 int n = 0;
  89
  90                 do {
  91                         sprintf(dev, LOOP_FORMAT, n);
  92                         s = query_loop(dev);
  93                         if (s && ENABLE_FEATURE_CLEAN_UP)
  94                                 free(s);
  95                 } while (s);
  96                 if ((opt == OPT_f) && !argv[0]) {
  97                         puts(dev);
  98                         return EXIT_SUCCESS;
  99                 }
 100         }
 101
 102         /* [-r] [-o OFS] {-f|LOOPDEV} FILE */
 103         if (argv[0] && ((opt & OPT_f) || argv[1])) {
 104                 unsigned long long offset = 0;
 105                 char *d = dev;
 106
 107                 if (opt == OPT_o)
 108                         offset = xatoull(opt_o);
 109                 if (opt != OPT_f)
 110                         d = *(argv++);
 111
 112                 if (argv[0]) {
 113                         if (set_loop(&d, argv[0], offset, (opt / OPT_r)) < 0)
 114                                 bb_simple_perror_msg_and_die(argv[0]);
 115                         return EXIT_SUCCESS;
 116                 }
 117         }
 118
 119         bb_show_usage();
 120         return EXIT_FAILURE;
 121 }