losetup: implement -r option. Closes 4033.
function old new delta packed_usage 28595 28633 +38 losetup_main 285 290 +5 singlemount 906 908 +2 set_loop 674 672 -2 Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
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@ -1164,7 +1164,7 @@ extern int del_loop(const char *device) FAST_FUNC;
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/* If *devname is not NULL, use that name, otherwise try to find free one,
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* malloc and return it in *devname.
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* return value: 1: read-only loopdev was setup, 0: rw, < 0: error */
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extern int set_loop(char **devname, const char *file, unsigned long long offset) FAST_FUNC;
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extern int set_loop(char **devname, const char *file, unsigned long long offset, int ro) FAST_FUNC;
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/* Like bb_ask below, but asks on stdin with no timeout. */
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char *bb_ask_stdin(const char * prompt) FAST_FUNC;
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10
libbb/loop.c
10
libbb/loop.c
@ -84,7 +84,7 @@ int FAST_FUNC del_loop(const char *device)
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search will re-use an existing loop device already bound to that
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file/offset if it finds one.
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*/
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int FAST_FUNC set_loop(char **device, const char *file, unsigned long long offset)
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int FAST_FUNC set_loop(char **device, const char *file, unsigned long long offset, int ro)
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{
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char dev[LOOP_NAMESIZE];
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char *try;
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@ -93,11 +93,13 @@ int FAST_FUNC set_loop(char **device, const char *file, unsigned long long offse
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int i, dfd, ffd, mode, rc = -1;
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/* Open the file. Barf if this doesn't work. */
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mode = O_RDWR;
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mode = ro ? O_RDONLY : O_RDWR;
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ffd = open(file, mode);
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if (ffd < 0) {
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mode = O_RDONLY;
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ffd = open(file, mode);
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if (mode != O_RDONLY) {
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mode = O_RDONLY;
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ffd = open(file, mode);
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}
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if (ffd < 0)
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return -errno;
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}
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@ -8,11 +8,12 @@
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*/
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//usage:#define losetup_trivial_usage
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//usage: "[-o OFS] LOOPDEV FILE - associate loop devices\n"
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//usage: "[-r] [-o OFS] LOOPDEV FILE - associate loop devices\n"
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//usage: " losetup -d LOOPDEV - disassociate\n"
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//usage: " losetup [-f] - show"
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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 first free loop device"
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//usage:
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//usage:#define losetup_notes_usage
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@ -37,11 +38,12 @@ int losetup_main(int argc UNUSED_PARAM, char **argv)
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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_r = (1 << 3), /* must be last */
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};
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/* max 2 args, all opts are mutually exclusive */
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/* max 2 args, -d,-o,-f opts are mutually exclusive */
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opt_complementary = "?2:d--of:o--df:f--do";
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opt = getopt32(argv, "do:f", &opt_o);
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opt = getopt32(argv, "do:fr", &opt_o);
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argv += optind;
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if (opt == OPT_o)
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@ -63,12 +65,12 @@ int losetup_main(int argc UNUSED_PARAM, char **argv)
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bb_show_usage();
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if (argv[1]) {
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/* [-o OFS] BLOCKDEV FILE */
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if (set_loop(&argv[0], argv[1], offset) < 0)
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/* [-r] [-o OFS] BLOCKDEV FILE */
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if (set_loop(&argv[0], argv[1], 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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/* [-o OFS] BLOCKDEV */
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/* [-r] [-o OFS] BLOCKDEV */
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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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@ -78,7 +80,7 @@ int losetup_main(int argc UNUSED_PARAM, char **argv)
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return EXIT_SUCCESS;
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}
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/* [-o OFS|-f] with no params */
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/* [-r] [-o OFS|-f] with no params */
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n = 0;
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while (1) {
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char *s;
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@ -1809,7 +1809,7 @@ static int singlemount(struct mntent *mp, int ignore_busy)
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if (ENABLE_FEATURE_MOUNT_LOOP && S_ISREG(st.st_mode)) {
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loopFile = bb_simplify_path(mp->mnt_fsname);
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mp->mnt_fsname = NULL; // will receive malloced loop dev name
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if (set_loop(&mp->mnt_fsname, loopFile, 0) < 0) {
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if (set_loop(&mp->mnt_fsname, loopFile, 0, /*ro:*/ 0) < 0) {
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if (errno == EPERM || errno == EACCES)
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bb_error_msg(bb_msg_perm_denied_are_you_root);
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else
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