diff options
Diffstat (limited to 'util-linux')
| -rw-r--r-- | util-linux/losetup.c | 27 | ||||
| -rw-r--r-- | util-linux/mount.c | 21 |
2 files changed, 46 insertions, 2 deletions
diff --git a/util-linux/losetup.c b/util-linux/losetup.c index 4424d9c..d356f49 100644 --- a/util-linux/losetup.c +++ b/util-linux/losetup.c @@ -127,12 +127,37 @@ int losetup_main(int argc UNUSED_PARAM, char **argv) d = *argv++; if (argv[0]) { - if (set_loop(&d, argv[0], offset, (opt & OPT_r)) < 0) + if (set_loop(&d, argv[0], offset, (opt & OPT_r) ? BB_LO_FLAGS_READ_ONLY : 0) < 0) bb_simple_perror_msg_and_die(argv[0]); return EXIT_SUCCESS; } } + /* TODO: util-linux 2.28 shows this when run w/o params: + * NAME SIZELIMIT OFFSET AUTOCLEAR RO BACK-FILE DIO + * /dev/loop0 0 0 1 0 /PATH/TO/FILE 0 + * + * implemented by reading /sys: + * + * open("/sys/block", O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC) = 3 + * newfstatat(3, "loop0/loop/backing_file", {st_mode=S_IFREG|0444, st_size=4096, ...}, 0) = 0 + * stat("/dev/loop0", {st_mode=S_IFBLK|0660, st_rdev=makedev(7, 0), ...}) = 0 + * open("/sys/dev/block/7:0/loop/offset", O_RDONLY|O_CLOEXEC) = 5 + * read(5, "0\n", 4096) = 2 + * open("/sys/dev/block/7:0/loop/sizelimit", O_RDONLY|O_CLOEXEC) = 5 + * read(5, "0\n", 4096) = 2 + * open("/sys/dev/block/7:0/loop/offset", O_RDONLY|O_CLOEXEC) = 5 + * read(5, "0\n", 4096) = 2 + * open("/sys/dev/block/7:0/loop/autoclear", O_RDONLY|O_CLOEXEC) = 5 + * read(5, "1\n", 4096) = 2 + * open("/sys/dev/block/7:0/ro", O_RDONLY|O_CLOEXEC) = 5 + * read(5, "0\n", 4096) = 2 + * open("/sys/dev/block/7:0/loop/backing_file", O_RDONLY|O_CLOEXEC) = 5 + * read(5, "/PATH/TO/FILE", 4096) = 37 + * open("/sys/dev/block/7:0/loop/dio", O_RDONLY|O_CLOEXEC) = 5 + * read(5, "0\n", 4096) = 2 + */ + bb_show_usage(); /* does not return */ /*return EXIT_FAILURE;*/ } diff --git a/util-linux/mount.c b/util-linux/mount.c index f0245f7..6bb1852 100644 --- a/util-linux/mount.c +++ b/util-linux/mount.c @@ -1887,6 +1887,7 @@ static int nfsmount(struct mntent *mp, unsigned long vfsflags, char *filteropts) // NB: mp->xxx fields may be trashed on exit static int singlemount(struct mntent *mp, int ignore_busy) { + int loopfd = -1; int rc = -1; unsigned long vfsflags; char *loopFile = NULL, *filteropts = NULL; @@ -2026,7 +2027,20 @@ static int singlemount(struct mntent *mp, int ignore_busy) if (ENABLE_FEATURE_MOUNT_LOOP && S_ISREG(st.st_mode)) { loopFile = bb_simplify_path(mp->mnt_fsname); mp->mnt_fsname = NULL; // will receive malloced loop dev name - if (set_loop(&mp->mnt_fsname, loopFile, 0, /*ro:*/ (vfsflags & MS_RDONLY)) < 0) { + + // mount always creates AUTOCLEARed loopdevs, so that umounting + // drops them without any code in the userspace. + // This happens since circa linux-2.6.25: + // commit 96c5865559cee0f9cbc5173f3c949f6ce3525581 + // Date: Wed Feb 6 01:36:27 2008 -0800 + // Subject: Allow auto-destruction of loop devices + loopfd = set_loop(&mp->mnt_fsname, + loopFile, + 0, + ((vfsflags & MS_RDONLY) ? BB_LO_FLAGS_READ_ONLY : 0) + | BB_LO_FLAGS_AUTOCLEAR + ); + if (loopfd < 0) { if (errno == EPERM || errno == EACCES) bb_error_msg(bb_msg_perm_denied_are_you_root); else @@ -2074,6 +2088,8 @@ static int singlemount(struct mntent *mp, int ignore_busy) } // If mount failed, clean up loop file (if any). + // (Newer kernels which support LO_FLAGS_AUTOCLEAR should not need this, + // merely "close(loopfd)" should do it?) if (ENABLE_FEATURE_MOUNT_LOOP && rc && loopFile) { del_loop(mp->mnt_fsname); if (ENABLE_FEATURE_CLEAN_UP) { @@ -2086,6 +2102,9 @@ static int singlemount(struct mntent *mp, int ignore_busy) if (ENABLE_FEATURE_CLEAN_UP) free(filteropts); + if (loopfd >= 0) + close(loopfd); + if (errno == EBUSY && ignore_busy) return 0; if (errno == ENOENT && (vfsflags & MOUNT_NOFAIL)) |