1 /* vi: set sw=4 ts=4: */
3 * Mini losetup implementation for busybox
5 * Copyright (C) 2002 Matt Kraai.
7 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
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\n"
14 //usage: " losetup -f - show next free loop device"
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/use next free loop device"
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"
30 /* 1048575 is a max possible minor number in Linux circa 2010 */
31 /* for now use something less extreme */
32 #define MAX_LOOP_NUM 1023
34 int losetup_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
35 int losetup_main(int argc UNUSED_PARAM, char **argv)
39 char dev[LOOP_NAMESIZE];
45 OPT_r = (1 << 4), /* must be last */
48 opt_complementary = "?2:d--ofar:a--ofr";
49 opt = getopt32(argv, "do:far", &opt_o);
53 if (!opt && argv[0] && !argv[1]) {
56 s = query_loop(argv[0]);
58 bb_simple_perror_msg_and_die(argv[0]);
59 printf("%s: %s\n", argv[0], s);
60 if (ENABLE_FEATURE_CLEAN_UP)
66 if (opt == OPT_d && argv[0]) {
67 if (del_loop(argv[0]))
68 bb_simple_perror_msg_and_die(argv[0]);
75 for (n = 0; n < MAX_LOOP_NUM; n++) {
78 sprintf(dev, LOOP_FORMAT, n);
81 printf("%s: %s\n", dev, s);
95 bb_error_msg_and_die("no free loop devices");
96 sprintf(dev, LOOP_FORMAT, n++);
100 /* now: dev is next free "/dev/loopN" */
101 if ((opt == OPT_f) && !argv[0]) {
107 /* [-r] [-o OFS] {-f|LOOPDEV} FILE */
108 if (argv[0] && ((opt & OPT_f) || argv[1])) {
109 unsigned long long offset = 0;
113 offset = xatoull(opt_o);
118 if (set_loop(&d, argv[0], offset, (opt & OPT_r)) < 0)
119 bb_simple_perror_msg_and_die(argv[0]);
124 bb_show_usage(); /* does not return */
125 /*return EXIT_FAILURE;*/