blob: d450b5a7825c3e8568093c3becd129c6be41b29b
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\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" |
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 | /* 1048575 is a max possible minor number in Linux circa 2010 */ |
31 | /* for now use something less extreme */ |
32 | #define MAX_LOOP_NUM 1023 |
33 | |
34 | int losetup_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
35 | int losetup_main(int argc UNUSED_PARAM, char **argv) |
36 | { |
37 | unsigned opt; |
38 | char *opt_o; |
39 | char dev[LOOP_NAMESIZE]; |
40 | enum { |
41 | OPT_d = (1 << 0), |
42 | OPT_o = (1 << 1), |
43 | OPT_f = (1 << 2), |
44 | OPT_a = (1 << 3), |
45 | OPT_r = (1 << 4), /* must be last */ |
46 | }; |
47 | |
48 | opt_complementary = "?2:d--ofar:a--ofr"; |
49 | opt = getopt32(argv, "do:far", &opt_o); |
50 | argv += optind; |
51 | |
52 | /* LOOPDEV */ |
53 | if (!opt && argv[0] && !argv[1]) { |
54 | char *s; |
55 | |
56 | s = query_loop(argv[0]); |
57 | if (!s) |
58 | bb_simple_perror_msg_and_die(argv[0]); |
59 | printf("%s: %s\n", argv[0], s); |
60 | if (ENABLE_FEATURE_CLEAN_UP) |
61 | free(s); |
62 | return EXIT_SUCCESS; |
63 | } |
64 | |
65 | /* -d LOOPDEV */ |
66 | if (opt == OPT_d && argv[0]) { |
67 | if (del_loop(argv[0])) |
68 | bb_simple_perror_msg_and_die(argv[0]); |
69 | return EXIT_SUCCESS; |
70 | } |
71 | |
72 | /* -a */ |
73 | if (opt == OPT_a) { |
74 | int n; |
75 | for (n = 0; n < MAX_LOOP_NUM; n++) { |
76 | char *s; |
77 | |
78 | sprintf(dev, LOOP_FORMAT, n); |
79 | s = query_loop(dev); |
80 | if (s) { |
81 | printf("%s: %s\n", dev, s); |
82 | free(s); |
83 | } |
84 | } |
85 | return EXIT_SUCCESS; |
86 | } |
87 | |
88 | /* contains -f */ |
89 | if (opt & OPT_f) { |
90 | char *s; |
91 | int n = 0; |
92 | |
93 | do { |
94 | if (n > MAX_LOOP_NUM) |
95 | bb_error_msg_and_die("no free loop devices"); |
96 | sprintf(dev, LOOP_FORMAT, n++); |
97 | s = query_loop(dev); |
98 | free(s); |
99 | } while (s); |
100 | /* now: dev is next free "/dev/loopN" */ |
101 | if ((opt == OPT_f) && !argv[0]) { |
102 | puts(dev); |
103 | return EXIT_SUCCESS; |
104 | } |
105 | } |
106 | |
107 | /* [-r] [-o OFS] {-f|LOOPDEV} FILE */ |
108 | if (argv[0] && ((opt & OPT_f) || argv[1])) { |
109 | unsigned long long offset = 0; |
110 | char *d = dev; |
111 | |
112 | if (opt & OPT_o) |
113 | offset = xatoull(opt_o); |
114 | if (!(opt & OPT_f)) |
115 | d = *argv++; |
116 | |
117 | if (argv[0]) { |
118 | if (set_loop(&d, argv[0], offset, (opt & OPT_r)) < 0) |
119 | bb_simple_perror_msg_and_die(argv[0]); |
120 | return EXIT_SUCCESS; |
121 | } |
122 | } |
123 | |
124 | bb_show_usage(); /* does not return */ |
125 | /*return EXIT_FAILURE;*/ |
126 | } |
127 |