mirror of
https://github.com/topjohnwu/ndk-busybox.git
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139 lines
3.6 KiB
C
139 lines
3.6 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* Mini losetup implementation for busybox
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*
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* Copyright (C) 2002 Matt Kraai.
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*
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* Licensed under GPLv2 or later, see file LICENSE in this source tree.
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*/
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//config:config LOSETUP
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//config: bool "losetup"
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//config: default y
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//config: select PLATFORM_LINUX
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//config: help
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//config: losetup is used to associate or detach a loop device with a regular
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//config: file or block device, and to query the status of a loop device. This
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//config: version does not currently support enabling data encryption.
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//kbuild:lib-$(CONFIG_LOSETUP) += losetup.o
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//applet:IF_LOSETUP(APPLET(losetup, BB_DIR_SBIN, BB_SUID_DROP))
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//usage:#define losetup_trivial_usage
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//usage: "[-r] [-o OFS] {-f|LOOPDEV} FILE - associate loop devices\n"
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//usage: " losetup -d LOOPDEV - disassociate\n"
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//usage: " losetup -a - show status\n"
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//usage: " losetup -f - show next free loop device"
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//usage:#define losetup_full_usage "\n\n"
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//usage: " -o OFS Start OFS bytes into FILE"
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//usage: "\n -r Read-only"
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//usage: "\n -f Show/use next free loop device"
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//usage:
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//usage:#define losetup_notes_usage
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//usage: "One argument (losetup /dev/loop1) will display the current association\n"
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//usage: "(if any), or disassociate it (with -d). The display shows the offset\n"
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//usage: "and filename of the file the loop device is currently bound to.\n\n"
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//usage: "Two arguments (losetup /dev/loop1 file.img) create a new association,\n"
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//usage: "with an optional offset (-o 12345). Encryption is not yet supported.\n"
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//usage: "losetup -f will show the first loop free loop device\n\n"
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#include "libbb.h"
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/* 1048575 is a max possible minor number in Linux circa 2010 */
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/* for now use something less extreme */
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#define MAX_LOOP_NUM 1023
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int losetup_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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int losetup_main(int argc UNUSED_PARAM, char **argv)
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{
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unsigned opt;
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char *opt_o;
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char dev[LOOP_NAMESIZE];
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enum {
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OPT_d = (1 << 0),
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OPT_o = (1 << 1),
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OPT_f = (1 << 2),
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OPT_a = (1 << 3),
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OPT_r = (1 << 4), /* must be last */
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};
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opt_complementary = "?2:d--ofar:a--ofr";
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opt = getopt32(argv, "do:far", &opt_o);
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argv += optind;
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/* LOOPDEV */
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if (!opt && argv[0] && !argv[1]) {
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char *s;
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s = query_loop(argv[0]);
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if (!s)
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bb_simple_perror_msg_and_die(argv[0]);
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printf("%s: %s\n", argv[0], s);
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if (ENABLE_FEATURE_CLEAN_UP)
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free(s);
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return EXIT_SUCCESS;
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}
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/* -d LOOPDEV */
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if (opt == OPT_d && argv[0]) {
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if (del_loop(argv[0]))
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bb_simple_perror_msg_and_die(argv[0]);
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return EXIT_SUCCESS;
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}
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/* -a */
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if (opt == OPT_a) {
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int n;
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for (n = 0; n < MAX_LOOP_NUM; n++) {
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char *s;
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sprintf(dev, LOOP_FORMAT, n);
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s = query_loop(dev);
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if (s) {
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printf("%s: %s\n", dev, s);
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free(s);
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}
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}
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return EXIT_SUCCESS;
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}
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/* contains -f */
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if (opt & OPT_f) {
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char *s;
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int n = 0;
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do {
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if (n > MAX_LOOP_NUM)
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bb_error_msg_and_die("no free loop devices");
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sprintf(dev, LOOP_FORMAT, n++);
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s = query_loop(dev);
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free(s);
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} while (s);
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/* now: dev is next free "/dev/loopN" */
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if ((opt == OPT_f) && !argv[0]) {
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puts(dev);
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return EXIT_SUCCESS;
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}
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}
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/* [-r] [-o OFS] {-f|LOOPDEV} FILE */
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if (argv[0] && ((opt & OPT_f) || argv[1])) {
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unsigned long long offset = 0;
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char *d = dev;
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if (opt & OPT_o)
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offset = xatoull(opt_o);
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if (!(opt & OPT_f))
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d = *argv++;
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if (argv[0]) {
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if (set_loop(&d, argv[0], offset, (opt & OPT_r)) < 0)
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bb_simple_perror_msg_and_die(argv[0]);
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return EXIT_SUCCESS;
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}
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}
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bb_show_usage(); /* does not return */
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/*return EXIT_FAILURE;*/
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}
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