busybox/util-linux/umount.c

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/* vi: set sw=4 ts=4: */
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/*
* Mini umount implementation for busybox
*
* Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
Major rewrite of mount, umount, losetup. Untangled lots of code, shrunk things down a bit, fixed a number of funky corner cases, added support for several new features (things like mount --move, mount --bind, lazy unounts, automatic detection of loop mounts, and so on). Probably broke several other things, but it's fixable. (Bang on it, tell me what doesn't work for you...) Note: you no longer need to say "-o loop". It does that for you when necessary. Still need to add "user mount" support, which involves making mount suid. Not too hard to do under the new infrastructure, just haven't done it yet... The previous code had the following notes, that belong in the version control comments: - * 3/21/1999 Charles P. Wright <cpwright@cpwright.com> - * searches through fstab when -a is passed - * will try mounting stuff with all fses when passed -t auto - * - * 1999-04-17 Dave Cinege...Rewrote -t auto. Fixed ro mtab. - * - * 1999-10-07 Erik Andersen <andersen@codepoet.org>. - * Rewrite of a lot of code. Removed mtab usage (I plan on - * putting it back as a compile-time option some time), - * major adjustments to option parsing, and some serious - * dieting all around. - * - * 1999-11-06 mtab support is back - andersee - * - * 2000-01-12 Ben Collins <bcollins@debian.org>, Borrowed utils-linux's - * mount to add loop support. - * - * 2000-04-30 Dave Cinege <dcinege@psychosis.com> - * Rewrote fstab while loop and lower mount section. Can now do - * single mounts from fstab. Can override fstab options for single - * mount. Common mount_one call for single mounts and 'all'. Fixed - * mtab updating and stale entries. Removed 'remount' default. - *
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* Copyright (C) 2005 by Rob Landley <rob@landley.net>
*
* Licensed under GPLv2, see file LICENSE in this source tree.
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*/
//config:config UMOUNT
//config: bool "umount (4.5 kb)"
//config: default y
//config: select PLATFORM_LINUX
//config: help
//config: When you want to remove a mounted filesystem from its current mount
//config: point, for example when you are shutting down the system, the
//config: 'umount' utility is the tool to use. If you enabled the 'mount'
//config: utility, you almost certainly also want to enable 'umount'.
//config:
//config:config FEATURE_UMOUNT_ALL
//config: bool "Support -a (unmount all)"
//config: default y
//config: depends on UMOUNT
//config: help
//config: Support -a option to unmount all currently mounted filesystems.
//applet:IF_UMOUNT(APPLET_NOEXEC(umount, umount, BB_DIR_BIN, BB_SUID_DROP, umount))
/*
* On one hand, in some weird situations you'd want umount
* to not do anything surprising, to behave as a usual fork+execed executable.
*
* OTOH, there can be situations where execing would not succeed, or even hang
* (say, if executable is on a filesystem which is in trouble and accesses to it
* block in kernel).
* In this case, you might be actually happy if your standalone bbox shell
* does not fork+exec, but only forks and calls umount_main() which it already has!
* Let's go with NOEXEC.
*
* bb_common_bufsiz1 usage here is safe wrt NOEXEC: not expecting it to be zeroed.
*/
//kbuild:lib-$(CONFIG_UMOUNT) += umount.o
//usage:#define umount_trivial_usage
//usage: "[OPTIONS] FILESYSTEM|DIRECTORY"
//usage:#define umount_full_usage "\n\n"
//usage: "Unmount file systems\n"
//usage: IF_FEATURE_UMOUNT_ALL(
//usage: "\n -a Unmount all file systems" IF_FEATURE_MTAB_SUPPORT(" in /etc/mtab")
//usage: )
//usage: IF_FEATURE_MTAB_SUPPORT(
//usage: "\n -n Don't erase /etc/mtab entries"
//usage: )
//usage: "\n -r Try to remount devices as read-only if mount is busy"
//usage: "\n -l Lazy umount (detach filesystem)"
//usage: "\n -f Force umount (i.e., unreachable NFS server)"
//usage: IF_FEATURE_MOUNT_LOOP(
Revert "umount: make -d always active, add -D to suppress it" This reverts commit 86a03bee1d3d6990c03bf500836b19ec8a1c1f12. Since now our "mount -oloop" creates AUTOCLEARed loopdevs, we no longer need our umount to destroy loopdevs to match the usual util-linux behaviour. Now this revert fixes another, opposite bug: "explicit" mount /dev/loopN and then umount must not drop loopdevs! User complaint is as follows: It seems LOOP_CLR_FD called on a loop-*partition* removes the mapping of the whole *device* - which results in the following: root@LEDE:/# loop=$(losetup -f) root@LEDE:/# echo ${loop} /dev/loop2 root@LEDE:/# losetup ${loop} /IMAGE root@LEDE:/# ls -l ${loop}* brw------- 1 root root 7, 2 Mar 6 20:09 /dev/loop2 root@LEDE:/# partprobe ${loop} root@LEDE:/# ls -l ${loop}* brw------- 1 root root 7, 2 Mar 6 20:09 /dev/loop2 brw------- 1 root root 259, 8 Mar 6 21:59 /dev/loop2p1 brw------- 1 root root 259, 9 Mar 6 21:59 /dev/loop2p2 brw------- 1 root root 259, 10 Mar 6 21:59 /dev/loop2p3 brw------- 1 root root 259, 11 Mar 6 21:59 /dev/loop2p4 brw------- 1 root root 259, 12 Mar 6 21:59 /dev/loop2p5 brw------- 1 root root 259, 13 Mar 6 21:59 /dev/loop2p6 brw------- 1 root root 259, 14 Mar 6 21:59 /dev/loop2p7 brw------- 1 root root 259, 15 Mar 6 21:59 /dev/loop2p8 root@LEDE:/# mount ${loop}p8 /MOUNT # mount loop partition root@LEDE:/# losetup -a | grep $loop # loop dev mapping still there /dev/loop2: 0 /mnt/IMAGE root@LEDE:/# strace umount /MOUNT 2> /log # unmount loop partition root@LEDE:/# losetup -a | grep ${loop} # loop device mapping is gone root@LEDE:/# grep -i loop /log open("/dev/loop2p7", O_RDONLY|O_LARGEFILE) = 3 ioctl(3, LOOP_CLR_FD) = 0 root@LEDE:/# The strace was done to figure out, if maybe umount wrongly ioctl()'s the parent device instead of the partition - it doesn't. I already wasn't a fan of umount implicitly removing the mapping in the first place (as I usually setup and release loop devices with `losetup` and scripts needed to call umount differently in order to work and outside busybox). However taking above (kernel-)behaviour into account - umount calling ioctl(LOOP_CLR_FD) unconditionally potentially causes some nasty side effects Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2017-03-16 22:15:07 +05:30
//usage: "\n -d Free loop device if it has been used"
//usage: )
//usage:
//usage:#define umount_example_usage
//usage: "$ umount /dev/hdc1\n"
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#include <mntent.h>
#include <sys/mount.h>
#ifndef MNT_DETACH
# define MNT_DETACH 0x00000002
#endif
#include "libbb.h"
#include "common_bufsiz.h"
#if defined(__dietlibc__)
// TODO: This does not belong here.
/* 16.12.2006, Sampo Kellomaki (sampo@iki.fi)
* dietlibc-0.30 does not have implementation of getmntent_r() */
static struct mntent *getmntent_r(FILE* stream, struct mntent* result,
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char* buffer UNUSED_PARAM, int bufsize UNUSED_PARAM)
{
struct mntent* ment = getmntent(stream);
return memcpy(result, ment, sizeof(*ment));
}
#endif
/* ignored: -c -v -t -i */
#define OPTION_STRING "fldnra" "cvt:i"
#define OPT_FORCE (1 << 0) // Same as MNT_FORCE
#define OPT_LAZY (1 << 1) // Same as MNT_DETACH
Revert "umount: make -d always active, add -D to suppress it" This reverts commit 86a03bee1d3d6990c03bf500836b19ec8a1c1f12. Since now our "mount -oloop" creates AUTOCLEARed loopdevs, we no longer need our umount to destroy loopdevs to match the usual util-linux behaviour. Now this revert fixes another, opposite bug: "explicit" mount /dev/loopN and then umount must not drop loopdevs! User complaint is as follows: It seems LOOP_CLR_FD called on a loop-*partition* removes the mapping of the whole *device* - which results in the following: root@LEDE:/# loop=$(losetup -f) root@LEDE:/# echo ${loop} /dev/loop2 root@LEDE:/# losetup ${loop} /IMAGE root@LEDE:/# ls -l ${loop}* brw------- 1 root root 7, 2 Mar 6 20:09 /dev/loop2 root@LEDE:/# partprobe ${loop} root@LEDE:/# ls -l ${loop}* brw------- 1 root root 7, 2 Mar 6 20:09 /dev/loop2 brw------- 1 root root 259, 8 Mar 6 21:59 /dev/loop2p1 brw------- 1 root root 259, 9 Mar 6 21:59 /dev/loop2p2 brw------- 1 root root 259, 10 Mar 6 21:59 /dev/loop2p3 brw------- 1 root root 259, 11 Mar 6 21:59 /dev/loop2p4 brw------- 1 root root 259, 12 Mar 6 21:59 /dev/loop2p5 brw------- 1 root root 259, 13 Mar 6 21:59 /dev/loop2p6 brw------- 1 root root 259, 14 Mar 6 21:59 /dev/loop2p7 brw------- 1 root root 259, 15 Mar 6 21:59 /dev/loop2p8 root@LEDE:/# mount ${loop}p8 /MOUNT # mount loop partition root@LEDE:/# losetup -a | grep $loop # loop dev mapping still there /dev/loop2: 0 /mnt/IMAGE root@LEDE:/# strace umount /MOUNT 2> /log # unmount loop partition root@LEDE:/# losetup -a | grep ${loop} # loop device mapping is gone root@LEDE:/# grep -i loop /log open("/dev/loop2p7", O_RDONLY|O_LARGEFILE) = 3 ioctl(3, LOOP_CLR_FD) = 0 root@LEDE:/# The strace was done to figure out, if maybe umount wrongly ioctl()'s the parent device instead of the partition - it doesn't. I already wasn't a fan of umount implicitly removing the mapping in the first place (as I usually setup and release loop devices with `losetup` and scripts needed to call umount differently in order to work and outside busybox). However taking above (kernel-)behaviour into account - umount calling ioctl(LOOP_CLR_FD) unconditionally potentially causes some nasty side effects Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2017-03-16 22:15:07 +05:30
#define OPT_FREELOOP (1 << 2)
#define OPT_NO_MTAB (1 << 3)
#define OPT_REMOUNT (1 << 4)
#define OPT_ALL (ENABLE_FEATURE_UMOUNT_ALL ? (1 << 5) : 0)
int umount_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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int umount_main(int argc UNUSED_PARAM, char **argv)
{
int doForce;
Major rewrite of mount, umount, losetup. Untangled lots of code, shrunk things down a bit, fixed a number of funky corner cases, added support for several new features (things like mount --move, mount --bind, lazy unounts, automatic detection of loop mounts, and so on). Probably broke several other things, but it's fixable. (Bang on it, tell me what doesn't work for you...) Note: you no longer need to say "-o loop". It does that for you when necessary. Still need to add "user mount" support, which involves making mount suid. Not too hard to do under the new infrastructure, just haven't done it yet... The previous code had the following notes, that belong in the version control comments: - * 3/21/1999 Charles P. Wright <cpwright@cpwright.com> - * searches through fstab when -a is passed - * will try mounting stuff with all fses when passed -t auto - * - * 1999-04-17 Dave Cinege...Rewrote -t auto. Fixed ro mtab. - * - * 1999-10-07 Erik Andersen <andersen@codepoet.org>. - * Rewrite of a lot of code. Removed mtab usage (I plan on - * putting it back as a compile-time option some time), - * major adjustments to option parsing, and some serious - * dieting all around. - * - * 1999-11-06 mtab support is back - andersee - * - * 2000-01-12 Ben Collins <bcollins@debian.org>, Borrowed utils-linux's - * mount to add loop support. - * - * 2000-04-30 Dave Cinege <dcinege@psychosis.com> - * Rewrote fstab while loop and lower mount section. Can now do - * single mounts from fstab. Can override fstab options for single - * mount. Common mount_one call for single mounts and 'all'. Fixed - * mtab updating and stale entries. Removed 'remount' default. - *
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struct mntent me;
FILE *fp;
char *fstype = NULL;
int status = EXIT_SUCCESS;
unsigned opt;
Major rewrite of mount, umount, losetup. Untangled lots of code, shrunk things down a bit, fixed a number of funky corner cases, added support for several new features (things like mount --move, mount --bind, lazy unounts, automatic detection of loop mounts, and so on). Probably broke several other things, but it's fixable. (Bang on it, tell me what doesn't work for you...) Note: you no longer need to say "-o loop". It does that for you when necessary. Still need to add "user mount" support, which involves making mount suid. Not too hard to do under the new infrastructure, just haven't done it yet... The previous code had the following notes, that belong in the version control comments: - * 3/21/1999 Charles P. Wright <cpwright@cpwright.com> - * searches through fstab when -a is passed - * will try mounting stuff with all fses when passed -t auto - * - * 1999-04-17 Dave Cinege...Rewrote -t auto. Fixed ro mtab. - * - * 1999-10-07 Erik Andersen <andersen@codepoet.org>. - * Rewrite of a lot of code. Removed mtab usage (I plan on - * putting it back as a compile-time option some time), - * major adjustments to option parsing, and some serious - * dieting all around. - * - * 1999-11-06 mtab support is back - andersee - * - * 2000-01-12 Ben Collins <bcollins@debian.org>, Borrowed utils-linux's - * mount to add loop support. - * - * 2000-04-30 Dave Cinege <dcinege@psychosis.com> - * Rewrote fstab while loop and lower mount section. Can now do - * single mounts from fstab. Can override fstab options for single - * mount. Common mount_one call for single mounts and 'all'. Fixed - * mtab updating and stale entries. Removed 'remount' default. - *
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struct mtab_list {
char *dir;
char *device;
struct mtab_list *next;
Major rewrite of mount, umount, losetup. Untangled lots of code, shrunk things down a bit, fixed a number of funky corner cases, added support for several new features (things like mount --move, mount --bind, lazy unounts, automatic detection of loop mounts, and so on). Probably broke several other things, but it's fixable. (Bang on it, tell me what doesn't work for you...) Note: you no longer need to say "-o loop". It does that for you when necessary. Still need to add "user mount" support, which involves making mount suid. Not too hard to do under the new infrastructure, just haven't done it yet... The previous code had the following notes, that belong in the version control comments: - * 3/21/1999 Charles P. Wright <cpwright@cpwright.com> - * searches through fstab when -a is passed - * will try mounting stuff with all fses when passed -t auto - * - * 1999-04-17 Dave Cinege...Rewrote -t auto. Fixed ro mtab. - * - * 1999-10-07 Erik Andersen <andersen@codepoet.org>. - * Rewrite of a lot of code. Removed mtab usage (I plan on - * putting it back as a compile-time option some time), - * major adjustments to option parsing, and some serious - * dieting all around. - * - * 1999-11-06 mtab support is back - andersee - * - * 2000-01-12 Ben Collins <bcollins@debian.org>, Borrowed utils-linux's - * mount to add loop support. - * - * 2000-04-30 Dave Cinege <dcinege@psychosis.com> - * Rewrote fstab while loop and lower mount section. Can now do - * single mounts from fstab. Can override fstab options for single - * mount. Common mount_one call for single mounts and 'all'. Fixed - * mtab updating and stale entries. Removed 'remount' default. - *
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} *mtl, *m;
opt = getopt32(argv, OPTION_STRING, &fstype);
//argc -= optind;
argv += optind;
// MNT_FORCE and MNT_DETACH (from linux/fs.h) must match
// OPT_FORCE and OPT_LAZY.
BUILD_BUG_ON(OPT_FORCE != MNT_FORCE || OPT_LAZY != MNT_DETACH);
doForce = opt & (OPT_FORCE|OPT_LAZY);
Major rewrite of mount, umount, losetup. Untangled lots of code, shrunk things down a bit, fixed a number of funky corner cases, added support for several new features (things like mount --move, mount --bind, lazy unounts, automatic detection of loop mounts, and so on). Probably broke several other things, but it's fixable. (Bang on it, tell me what doesn't work for you...) Note: you no longer need to say "-o loop". It does that for you when necessary. Still need to add "user mount" support, which involves making mount suid. Not too hard to do under the new infrastructure, just haven't done it yet... The previous code had the following notes, that belong in the version control comments: - * 3/21/1999 Charles P. Wright <cpwright@cpwright.com> - * searches through fstab when -a is passed - * will try mounting stuff with all fses when passed -t auto - * - * 1999-04-17 Dave Cinege...Rewrote -t auto. Fixed ro mtab. - * - * 1999-10-07 Erik Andersen <andersen@codepoet.org>. - * Rewrite of a lot of code. Removed mtab usage (I plan on - * putting it back as a compile-time option some time), - * major adjustments to option parsing, and some serious - * dieting all around. - * - * 1999-11-06 mtab support is back - andersee - * - * 2000-01-12 Ben Collins <bcollins@debian.org>, Borrowed utils-linux's - * mount to add loop support. - * - * 2000-04-30 Dave Cinege <dcinege@psychosis.com> - * Rewrote fstab while loop and lower mount section. Can now do - * single mounts from fstab. Can override fstab options for single - * mount. Common mount_one call for single mounts and 'all'. Fixed - * mtab updating and stale entries. Removed 'remount' default. - *
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/* Get a list of mount points from mtab. We read them all in now mostly
* for umount -a (so we don't have to worry about the list changing while
* we iterate over it, or about getting stuck in a loop on the same failing
* entry. Notice that this also naturally reverses the list so that -a
* umounts the most recent entries first. */
m = mtl = NULL;
// If we're umounting all, then m points to the start of the list and
// the argument list should be empty (which will match all).
fp = setmntent(bb_path_mtab_file, "r");
if (!fp) {
if (opt & OPT_ALL)
bb_error_msg_and_die("can't open '%s'", bb_path_mtab_file);
} else {
setup_common_bufsiz();
while (getmntent_r(fp, &me, bb_common_bufsiz1, COMMON_BUFSIZE)) {
/* Match fstype (fstype==NULL matches always) */
if (!fstype_matches(me.mnt_type, fstype))
continue;
m = xzalloc(sizeof(*m));
m->next = mtl;
m->device = xstrdup(me.mnt_fsname);
m->dir = xstrdup(me.mnt_dir);
mtl = m;
}
endmntent(fp);
}
Major rewrite of mount, umount, losetup. Untangled lots of code, shrunk things down a bit, fixed a number of funky corner cases, added support for several new features (things like mount --move, mount --bind, lazy unounts, automatic detection of loop mounts, and so on). Probably broke several other things, but it's fixable. (Bang on it, tell me what doesn't work for you...) Note: you no longer need to say "-o loop". It does that for you when necessary. Still need to add "user mount" support, which involves making mount suid. Not too hard to do under the new infrastructure, just haven't done it yet... The previous code had the following notes, that belong in the version control comments: - * 3/21/1999 Charles P. Wright <cpwright@cpwright.com> - * searches through fstab when -a is passed - * will try mounting stuff with all fses when passed -t auto - * - * 1999-04-17 Dave Cinege...Rewrote -t auto. Fixed ro mtab. - * - * 1999-10-07 Erik Andersen <andersen@codepoet.org>. - * Rewrite of a lot of code. Removed mtab usage (I plan on - * putting it back as a compile-time option some time), - * major adjustments to option parsing, and some serious - * dieting all around. - * - * 1999-11-06 mtab support is back - andersee - * - * 2000-01-12 Ben Collins <bcollins@debian.org>, Borrowed utils-linux's - * mount to add loop support. - * - * 2000-04-30 Dave Cinege <dcinege@psychosis.com> - * Rewrote fstab while loop and lower mount section. Can now do - * single mounts from fstab. Can override fstab options for single - * mount. Common mount_one call for single mounts and 'all'. Fixed - * mtab updating and stale entries. Removed 'remount' default. - *
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// If we're not umounting all, we need at least one argument.
if (!(opt & OPT_ALL) && !fstype) {
if (!argv[0])
bb_show_usage();
m = NULL;
}
2006-09-17 21:58:10 +05:30
Major rewrite of mount, umount, losetup. Untangled lots of code, shrunk things down a bit, fixed a number of funky corner cases, added support for several new features (things like mount --move, mount --bind, lazy unounts, automatic detection of loop mounts, and so on). Probably broke several other things, but it's fixable. (Bang on it, tell me what doesn't work for you...) Note: you no longer need to say "-o loop". It does that for you when necessary. Still need to add "user mount" support, which involves making mount suid. Not too hard to do under the new infrastructure, just haven't done it yet... The previous code had the following notes, that belong in the version control comments: - * 3/21/1999 Charles P. Wright <cpwright@cpwright.com> - * searches through fstab when -a is passed - * will try mounting stuff with all fses when passed -t auto - * - * 1999-04-17 Dave Cinege...Rewrote -t auto. Fixed ro mtab. - * - * 1999-10-07 Erik Andersen <andersen@codepoet.org>. - * Rewrite of a lot of code. Removed mtab usage (I plan on - * putting it back as a compile-time option some time), - * major adjustments to option parsing, and some serious - * dieting all around. - * - * 1999-11-06 mtab support is back - andersee - * - * 2000-01-12 Ben Collins <bcollins@debian.org>, Borrowed utils-linux's - * mount to add loop support. - * - * 2000-04-30 Dave Cinege <dcinege@psychosis.com> - * Rewrote fstab while loop and lower mount section. Can now do - * single mounts from fstab. Can override fstab options for single - * mount. Common mount_one call for single mounts and 'all'. Fixed - * mtab updating and stale entries. Removed 'remount' default. - *
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// Loop through everything we're supposed to umount, and do so.
for (;;) {
Major rewrite of mount, umount, losetup. Untangled lots of code, shrunk things down a bit, fixed a number of funky corner cases, added support for several new features (things like mount --move, mount --bind, lazy unounts, automatic detection of loop mounts, and so on). Probably broke several other things, but it's fixable. (Bang on it, tell me what doesn't work for you...) Note: you no longer need to say "-o loop". It does that for you when necessary. Still need to add "user mount" support, which involves making mount suid. Not too hard to do under the new infrastructure, just haven't done it yet... The previous code had the following notes, that belong in the version control comments: - * 3/21/1999 Charles P. Wright <cpwright@cpwright.com> - * searches through fstab when -a is passed - * will try mounting stuff with all fses when passed -t auto - * - * 1999-04-17 Dave Cinege...Rewrote -t auto. Fixed ro mtab. - * - * 1999-10-07 Erik Andersen <andersen@codepoet.org>. - * Rewrite of a lot of code. Removed mtab usage (I plan on - * putting it back as a compile-time option some time), - * major adjustments to option parsing, and some serious - * dieting all around. - * - * 1999-11-06 mtab support is back - andersee - * - * 2000-01-12 Ben Collins <bcollins@debian.org>, Borrowed utils-linux's - * mount to add loop support. - * - * 2000-04-30 Dave Cinege <dcinege@psychosis.com> - * Rewrote fstab while loop and lower mount section. Can now do - * single mounts from fstab. Can override fstab options for single - * mount. Common mount_one call for single mounts and 'all'. Fixed - * mtab updating and stale entries. Removed 'remount' default. - *
2005-08-11 02:05:54 +05:30
int curstat;
char *zapit = *argv;
char *path;
// Do we already know what to umount this time through the loop?
if (m)
path = xstrdup(m->dir);
// For umount -a, end of mtab means time to exit.
else if (opt & OPT_ALL)
break;
// Use command line argument (and look it up in mtab list)
Major rewrite of mount, umount, losetup. Untangled lots of code, shrunk things down a bit, fixed a number of funky corner cases, added support for several new features (things like mount --move, mount --bind, lazy unounts, automatic detection of loop mounts, and so on). Probably broke several other things, but it's fixable. (Bang on it, tell me what doesn't work for you...) Note: you no longer need to say "-o loop". It does that for you when necessary. Still need to add "user mount" support, which involves making mount suid. Not too hard to do under the new infrastructure, just haven't done it yet... The previous code had the following notes, that belong in the version control comments: - * 3/21/1999 Charles P. Wright <cpwright@cpwright.com> - * searches through fstab when -a is passed - * will try mounting stuff with all fses when passed -t auto - * - * 1999-04-17 Dave Cinege...Rewrote -t auto. Fixed ro mtab. - * - * 1999-10-07 Erik Andersen <andersen@codepoet.org>. - * Rewrite of a lot of code. Removed mtab usage (I plan on - * putting it back as a compile-time option some time), - * major adjustments to option parsing, and some serious - * dieting all around. - * - * 1999-11-06 mtab support is back - andersee - * - * 2000-01-12 Ben Collins <bcollins@debian.org>, Borrowed utils-linux's - * mount to add loop support. - * - * 2000-04-30 Dave Cinege <dcinege@psychosis.com> - * Rewrote fstab while loop and lower mount section. Can now do - * single mounts from fstab. Can override fstab options for single - * mount. Common mount_one call for single mounts and 'all'. Fixed - * mtab updating and stale entries. Removed 'remount' default. - *
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else {
if (!zapit)
break;
argv++;
path = xmalloc_realpath(zapit);
if (path) {
for (m = mtl; m; m = m->next)
if (strcmp(path, m->dir) == 0 || strcmp(path, m->device) == 0)
break;
}
}
// If we couldn't find this sucker in /etc/mtab, punt by passing our
// command line argument straight to the umount syscall. Otherwise,
// umount the directory even if we were given the block device.
if (m) zapit = m->dir;
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// umount from util-linux 2.22.2 does not do this:
// umount -f uses umount2(MNT_FORCE) immediately,
// not trying umount() first.
// (Strangely, umount -fl ignores -f: it is equivalent to umount -l.
// We do pass both flags in this case)
#if 0
Major rewrite of mount, umount, losetup. Untangled lots of code, shrunk things down a bit, fixed a number of funky corner cases, added support for several new features (things like mount --move, mount --bind, lazy unounts, automatic detection of loop mounts, and so on). Probably broke several other things, but it's fixable. (Bang on it, tell me what doesn't work for you...) Note: you no longer need to say "-o loop". It does that for you when necessary. Still need to add "user mount" support, which involves making mount suid. Not too hard to do under the new infrastructure, just haven't done it yet... The previous code had the following notes, that belong in the version control comments: - * 3/21/1999 Charles P. Wright <cpwright@cpwright.com> - * searches through fstab when -a is passed - * will try mounting stuff with all fses when passed -t auto - * - * 1999-04-17 Dave Cinege...Rewrote -t auto. Fixed ro mtab. - * - * 1999-10-07 Erik Andersen <andersen@codepoet.org>. - * Rewrite of a lot of code. Removed mtab usage (I plan on - * putting it back as a compile-time option some time), - * major adjustments to option parsing, and some serious - * dieting all around. - * - * 1999-11-06 mtab support is back - andersee - * - * 2000-01-12 Ben Collins <bcollins@debian.org>, Borrowed utils-linux's - * mount to add loop support. - * - * 2000-04-30 Dave Cinege <dcinege@psychosis.com> - * Rewrote fstab while loop and lower mount section. Can now do - * single mounts from fstab. Can override fstab options for single - * mount. Common mount_one call for single mounts and 'all'. Fixed - * mtab updating and stale entries. Removed 'remount' default. - *
2005-08-11 02:05:54 +05:30
// Let's ask the thing nicely to unmount.
curstat = umount(zapit);
// Unmount with force and/or lazy flags, if necessary.
if (curstat && doForce)
#endif
curstat = umount2(zapit, doForce);
1999-10-05 21:54:54 +05:30
// If still can't umount, maybe remount read-only?
if (curstat) {
if ((opt & OPT_REMOUNT) && errno == EBUSY && m) {
// Note! Even if we succeed here, later we should not
// free loop device or erase mtab entry!
const char *msg = "%s busy - remounted read-only";
curstat = mount(m->device, zapit, NULL, MS_REMOUNT|MS_RDONLY, NULL);
if (curstat) {
2008-07-21 19:16:54 +05:30
msg = "can't remount %s read-only";
status = EXIT_FAILURE;
}
bb_error_msg(msg, m->device);
} else {
status = EXIT_FAILURE;
bb_perror_msg("can't unmount %s", zapit);
}
} else {
// De-allocate the loop device. This ioctl should be ignored on
// any non-loop block devices.
Revert "umount: make -d always active, add -D to suppress it" This reverts commit 86a03bee1d3d6990c03bf500836b19ec8a1c1f12. Since now our "mount -oloop" creates AUTOCLEARed loopdevs, we no longer need our umount to destroy loopdevs to match the usual util-linux behaviour. Now this revert fixes another, opposite bug: "explicit" mount /dev/loopN and then umount must not drop loopdevs! User complaint is as follows: It seems LOOP_CLR_FD called on a loop-*partition* removes the mapping of the whole *device* - which results in the following: root@LEDE:/# loop=$(losetup -f) root@LEDE:/# echo ${loop} /dev/loop2 root@LEDE:/# losetup ${loop} /IMAGE root@LEDE:/# ls -l ${loop}* brw------- 1 root root 7, 2 Mar 6 20:09 /dev/loop2 root@LEDE:/# partprobe ${loop} root@LEDE:/# ls -l ${loop}* brw------- 1 root root 7, 2 Mar 6 20:09 /dev/loop2 brw------- 1 root root 259, 8 Mar 6 21:59 /dev/loop2p1 brw------- 1 root root 259, 9 Mar 6 21:59 /dev/loop2p2 brw------- 1 root root 259, 10 Mar 6 21:59 /dev/loop2p3 brw------- 1 root root 259, 11 Mar 6 21:59 /dev/loop2p4 brw------- 1 root root 259, 12 Mar 6 21:59 /dev/loop2p5 brw------- 1 root root 259, 13 Mar 6 21:59 /dev/loop2p6 brw------- 1 root root 259, 14 Mar 6 21:59 /dev/loop2p7 brw------- 1 root root 259, 15 Mar 6 21:59 /dev/loop2p8 root@LEDE:/# mount ${loop}p8 /MOUNT # mount loop partition root@LEDE:/# losetup -a | grep $loop # loop dev mapping still there /dev/loop2: 0 /mnt/IMAGE root@LEDE:/# strace umount /MOUNT 2> /log # unmount loop partition root@LEDE:/# losetup -a | grep ${loop} # loop device mapping is gone root@LEDE:/# grep -i loop /log open("/dev/loop2p7", O_RDONLY|O_LARGEFILE) = 3 ioctl(3, LOOP_CLR_FD) = 0 root@LEDE:/# The strace was done to figure out, if maybe umount wrongly ioctl()'s the parent device instead of the partition - it doesn't. I already wasn't a fan of umount implicitly removing the mapping in the first place (as I usually setup and release loop devices with `losetup` and scripts needed to call umount differently in order to work and outside busybox). However taking above (kernel-)behaviour into account - umount calling ioctl(LOOP_CLR_FD) unconditionally potentially causes some nasty side effects Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2017-03-16 22:15:07 +05:30
if (ENABLE_FEATURE_MOUNT_LOOP && (opt & OPT_FREELOOP) && m)
del_loop(m->device);
if (ENABLE_FEATURE_MTAB_SUPPORT && !(opt & OPT_NO_MTAB) && m)
erase_mtab(m->dir);
Major rewrite of mount, umount, losetup. Untangled lots of code, shrunk things down a bit, fixed a number of funky corner cases, added support for several new features (things like mount --move, mount --bind, lazy unounts, automatic detection of loop mounts, and so on). Probably broke several other things, but it's fixable. (Bang on it, tell me what doesn't work for you...) Note: you no longer need to say "-o loop". It does that for you when necessary. Still need to add "user mount" support, which involves making mount suid. Not too hard to do under the new infrastructure, just haven't done it yet... The previous code had the following notes, that belong in the version control comments: - * 3/21/1999 Charles P. Wright <cpwright@cpwright.com> - * searches through fstab when -a is passed - * will try mounting stuff with all fses when passed -t auto - * - * 1999-04-17 Dave Cinege...Rewrote -t auto. Fixed ro mtab. - * - * 1999-10-07 Erik Andersen <andersen@codepoet.org>. - * Rewrite of a lot of code. Removed mtab usage (I plan on - * putting it back as a compile-time option some time), - * major adjustments to option parsing, and some serious - * dieting all around. - * - * 1999-11-06 mtab support is back - andersee - * - * 2000-01-12 Ben Collins <bcollins@debian.org>, Borrowed utils-linux's - * mount to add loop support. - * - * 2000-04-30 Dave Cinege <dcinege@psychosis.com> - * Rewrote fstab while loop and lower mount section. Can now do - * single mounts from fstab. Can override fstab options for single - * mount. Common mount_one call for single mounts and 'all'. Fixed - * mtab updating and stale entries. Removed 'remount' default. - *
2005-08-11 02:05:54 +05:30
}
Major rewrite of mount, umount, losetup. Untangled lots of code, shrunk things down a bit, fixed a number of funky corner cases, added support for several new features (things like mount --move, mount --bind, lazy unounts, automatic detection of loop mounts, and so on). Probably broke several other things, but it's fixable. (Bang on it, tell me what doesn't work for you...) Note: you no longer need to say "-o loop". It does that for you when necessary. Still need to add "user mount" support, which involves making mount suid. Not too hard to do under the new infrastructure, just haven't done it yet... The previous code had the following notes, that belong in the version control comments: - * 3/21/1999 Charles P. Wright <cpwright@cpwright.com> - * searches through fstab when -a is passed - * will try mounting stuff with all fses when passed -t auto - * - * 1999-04-17 Dave Cinege...Rewrote -t auto. Fixed ro mtab. - * - * 1999-10-07 Erik Andersen <andersen@codepoet.org>. - * Rewrite of a lot of code. Removed mtab usage (I plan on - * putting it back as a compile-time option some time), - * major adjustments to option parsing, and some serious - * dieting all around. - * - * 1999-11-06 mtab support is back - andersee - * - * 2000-01-12 Ben Collins <bcollins@debian.org>, Borrowed utils-linux's - * mount to add loop support. - * - * 2000-04-30 Dave Cinege <dcinege@psychosis.com> - * Rewrote fstab while loop and lower mount section. Can now do - * single mounts from fstab. Can override fstab options for single - * mount. Common mount_one call for single mounts and 'all'. Fixed - * mtab updating and stale entries. Removed 'remount' default. - *
2005-08-11 02:05:54 +05:30
// Find next matching mtab entry for -a or umount /dev
// Note this means that "umount /dev/blah" will unmount all instances
// of /dev/blah, not just the most recent.
if (m) {
while ((m = m->next) != NULL)
// NB: if m is non-NULL, path is non-NULL as well
if ((opt & OPT_ALL) || strcmp(path, m->device) == 0)
break;
}
free(path);
}
Major rewrite of mount, umount, losetup. Untangled lots of code, shrunk things down a bit, fixed a number of funky corner cases, added support for several new features (things like mount --move, mount --bind, lazy unounts, automatic detection of loop mounts, and so on). Probably broke several other things, but it's fixable. (Bang on it, tell me what doesn't work for you...) Note: you no longer need to say "-o loop". It does that for you when necessary. Still need to add "user mount" support, which involves making mount suid. Not too hard to do under the new infrastructure, just haven't done it yet... The previous code had the following notes, that belong in the version control comments: - * 3/21/1999 Charles P. Wright <cpwright@cpwright.com> - * searches through fstab when -a is passed - * will try mounting stuff with all fses when passed -t auto - * - * 1999-04-17 Dave Cinege...Rewrote -t auto. Fixed ro mtab. - * - * 1999-10-07 Erik Andersen <andersen@codepoet.org>. - * Rewrite of a lot of code. Removed mtab usage (I plan on - * putting it back as a compile-time option some time), - * major adjustments to option parsing, and some serious - * dieting all around. - * - * 1999-11-06 mtab support is back - andersee - * - * 2000-01-12 Ben Collins <bcollins@debian.org>, Borrowed utils-linux's - * mount to add loop support. - * - * 2000-04-30 Dave Cinege <dcinege@psychosis.com> - * Rewrote fstab while loop and lower mount section. Can now do - * single mounts from fstab. Can override fstab options for single - * mount. Common mount_one call for single mounts and 'all'. Fixed - * mtab updating and stale entries. Removed 'remount' default. - *
2005-08-11 02:05:54 +05:30
// Free mtab list if necessary
if (ENABLE_FEATURE_CLEAN_UP) {
while (mtl) {
m = mtl->next;
Major rewrite of mount, umount, losetup. Untangled lots of code, shrunk things down a bit, fixed a number of funky corner cases, added support for several new features (things like mount --move, mount --bind, lazy unounts, automatic detection of loop mounts, and so on). Probably broke several other things, but it's fixable. (Bang on it, tell me what doesn't work for you...) Note: you no longer need to say "-o loop". It does that for you when necessary. Still need to add "user mount" support, which involves making mount suid. Not too hard to do under the new infrastructure, just haven't done it yet... The previous code had the following notes, that belong in the version control comments: - * 3/21/1999 Charles P. Wright <cpwright@cpwright.com> - * searches through fstab when -a is passed - * will try mounting stuff with all fses when passed -t auto - * - * 1999-04-17 Dave Cinege...Rewrote -t auto. Fixed ro mtab. - * - * 1999-10-07 Erik Andersen <andersen@codepoet.org>. - * Rewrite of a lot of code. Removed mtab usage (I plan on - * putting it back as a compile-time option some time), - * major adjustments to option parsing, and some serious - * dieting all around. - * - * 1999-11-06 mtab support is back - andersee - * - * 2000-01-12 Ben Collins <bcollins@debian.org>, Borrowed utils-linux's - * mount to add loop support. - * - * 2000-04-30 Dave Cinege <dcinege@psychosis.com> - * Rewrote fstab while loop and lower mount section. Can now do - * single mounts from fstab. Can override fstab options for single - * mount. Common mount_one call for single mounts and 'all'. Fixed - * mtab updating and stale entries. Removed 'remount' default. - *
2005-08-11 02:05:54 +05:30
free(mtl->device);
free(mtl->dir);
free(mtl);
mtl = m;
Major rewrite of mount, umount, losetup. Untangled lots of code, shrunk things down a bit, fixed a number of funky corner cases, added support for several new features (things like mount --move, mount --bind, lazy unounts, automatic detection of loop mounts, and so on). Probably broke several other things, but it's fixable. (Bang on it, tell me what doesn't work for you...) Note: you no longer need to say "-o loop". It does that for you when necessary. Still need to add "user mount" support, which involves making mount suid. Not too hard to do under the new infrastructure, just haven't done it yet... The previous code had the following notes, that belong in the version control comments: - * 3/21/1999 Charles P. Wright <cpwright@cpwright.com> - * searches through fstab when -a is passed - * will try mounting stuff with all fses when passed -t auto - * - * 1999-04-17 Dave Cinege...Rewrote -t auto. Fixed ro mtab. - * - * 1999-10-07 Erik Andersen <andersen@codepoet.org>. - * Rewrite of a lot of code. Removed mtab usage (I plan on - * putting it back as a compile-time option some time), - * major adjustments to option parsing, and some serious - * dieting all around. - * - * 1999-11-06 mtab support is back - andersee - * - * 2000-01-12 Ben Collins <bcollins@debian.org>, Borrowed utils-linux's - * mount to add loop support. - * - * 2000-04-30 Dave Cinege <dcinege@psychosis.com> - * Rewrote fstab while loop and lower mount section. Can now do - * single mounts from fstab. Can override fstab options for single - * mount. Common mount_one call for single mounts and 'all'. Fixed - * mtab updating and stale entries. Removed 'remount' default. - *
2005-08-11 02:05:54 +05:30
}
}
1999-10-09 05:55:00 +05:30
Major rewrite of mount, umount, losetup. Untangled lots of code, shrunk things down a bit, fixed a number of funky corner cases, added support for several new features (things like mount --move, mount --bind, lazy unounts, automatic detection of loop mounts, and so on). Probably broke several other things, but it's fixable. (Bang on it, tell me what doesn't work for you...) Note: you no longer need to say "-o loop". It does that for you when necessary. Still need to add "user mount" support, which involves making mount suid. Not too hard to do under the new infrastructure, just haven't done it yet... The previous code had the following notes, that belong in the version control comments: - * 3/21/1999 Charles P. Wright <cpwright@cpwright.com> - * searches through fstab when -a is passed - * will try mounting stuff with all fses when passed -t auto - * - * 1999-04-17 Dave Cinege...Rewrote -t auto. Fixed ro mtab. - * - * 1999-10-07 Erik Andersen <andersen@codepoet.org>. - * Rewrite of a lot of code. Removed mtab usage (I plan on - * putting it back as a compile-time option some time), - * major adjustments to option parsing, and some serious - * dieting all around. - * - * 1999-11-06 mtab support is back - andersee - * - * 2000-01-12 Ben Collins <bcollins@debian.org>, Borrowed utils-linux's - * mount to add loop support. - * - * 2000-04-30 Dave Cinege <dcinege@psychosis.com> - * Rewrote fstab while loop and lower mount section. Can now do - * single mounts from fstab. Can override fstab options for single - * mount. Common mount_one call for single mounts and 'all'. Fixed - * mtab updating and stale entries. Removed 'remount' default. - *
2005-08-11 02:05:54 +05:30
return status;
}