1 | /* vi: set sw=4 ts=4: */
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2 | /*
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3 | * Mini losetup implementation for busybox
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4 | *
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5 | * Copyright (C) 2002 Matt Kraai.
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6 | *
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7 | * Licensed under GPLv2 or later, see file LICENSE in this source tree.
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8 | */
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9 |
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10 | //usage:#define losetup_trivial_usage
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11 | //usage: "[-r] [-o OFS] {-f|LOOPDEV} FILE - associate loop devices\n"
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12 | //usage: " losetup -d LOOPDEV - disassociate\n"
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13 | //usage: " losetup -a - show status\n"
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14 | //usage: " losetup -f - show next free loop device"
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15 | //usage:#define losetup_full_usage "\n\n"
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16 | //usage: " -o OFS Start OFS bytes into FILE"
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17 | //usage: "\n -r Read-only"
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18 | //usage: "\n -f Show/use next free loop device"
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19 | //usage:
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20 | //usage:#define losetup_notes_usage
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21 | //usage: "One argument (losetup /dev/loop1) will display the current association\n"
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22 | //usage: "(if any), or disassociate it (with -d). The display shows the offset\n"
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23 | //usage: "and filename of the file the loop device is currently bound to.\n\n"
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24 | //usage: "Two arguments (losetup /dev/loop1 file.img) create a new association,\n"
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25 | //usage: "with an optional offset (-o 12345). Encryption is not yet supported.\n"
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26 | //usage: "losetup -f will show the first loop free loop device\n\n"
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27 |
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28 | #include "libbb.h"
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29 |
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30 | /* 1048575 is a max possible minor number in Linux circa 2010 */
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31 | /* for now use something less extreme */
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32 | #define MAX_LOOP_NUM 1023
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33 |
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34 | int losetup_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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35 | int losetup_main(int argc UNUSED_PARAM, char **argv)
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36 | {
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37 | unsigned opt;
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38 | char *opt_o;
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39 | char dev[LOOP_NAMESIZE];
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40 | enum {
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41 | OPT_d = (1 << 0),
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42 | OPT_o = (1 << 1),
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43 | OPT_f = (1 << 2),
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44 | OPT_a = (1 << 3),
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45 | OPT_r = (1 << 4), /* must be last */
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46 | };
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47 |
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48 | opt_complementary = "?2:d--ofar:a--ofr";
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49 | opt = getopt32(argv, "do:far", &opt_o);
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50 | argv += optind;
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51 |
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52 | /* LOOPDEV */
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53 | if (!opt && argv[0] && !argv[1]) {
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54 | char *s;
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55 |
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56 | s = query_loop(argv[0]);
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57 | if (!s)
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58 | bb_simple_perror_msg_and_die(argv[0]);
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59 | printf("%s: %s\n", argv[0], s);
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60 | if (ENABLE_FEATURE_CLEAN_UP)
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61 | free(s);
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62 | return EXIT_SUCCESS;
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63 | }
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64 |
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65 | /* -d LOOPDEV */
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66 | if (opt == OPT_d && argv[0]) {
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67 | if (del_loop(argv[0]))
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68 | bb_simple_perror_msg_and_die(argv[0]);
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69 | return EXIT_SUCCESS;
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70 | }
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71 |
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72 | /* -a */
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73 | if (opt == OPT_a) {
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74 | int n;
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75 | for (n = 0; n < MAX_LOOP_NUM; n++) {
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76 | char *s;
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77 |
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78 | sprintf(dev, LOOP_FORMAT, n);
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79 | s = query_loop(dev);
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80 | if (s) {
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81 | printf("%s: %s\n", dev, s);
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82 | free(s);
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83 | }
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84 | }
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85 | return EXIT_SUCCESS;
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86 | }
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87 |
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88 | /* contains -f */
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89 | if (opt & OPT_f) {
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90 | char *s;
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91 | int n = 0;
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92 |
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93 | do {
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94 | if (n > MAX_LOOP_NUM)
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95 | bb_error_msg_and_die("no free loop devices");
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96 | sprintf(dev, LOOP_FORMAT, n++);
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97 | s = query_loop(dev);
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98 | free(s);
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99 | } while (s);
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100 | /* now: dev is next free "/dev/loopN" */
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101 | if ((opt == OPT_f) && !argv[0]) {
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102 | puts(dev);
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103 | return EXIT_SUCCESS;
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104 | }
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105 | }
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106 |
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107 | /* [-r] [-o OFS] {-f|LOOPDEV} FILE */
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108 | if (argv[0] && ((opt & OPT_f) || argv[1])) {
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109 | unsigned long long offset = 0;
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110 | char *d = dev;
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111 |
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112 | if (opt & OPT_o)
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113 | offset = xatoull(opt_o);
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114 | if (!(opt & OPT_f))
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115 | d = *argv++;
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116 |
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117 | if (argv[0]) {
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118 | if (set_loop(&d, argv[0], offset, (opt & OPT_r)) < 0)
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119 | bb_simple_perror_msg_and_die(argv[0]);
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120 | return EXIT_SUCCESS;
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121 | }
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122 | }
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123 |
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124 | bb_show_usage(); /* does not return */
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125 | /*return EXIT_FAILURE;*/
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126 | }
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