1 /* vi: set sw=4 ts=4: */
3 * Mini umount implementation for busybox
5 * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
6 * Copyright (C) 2005 by Rob Landley <rob@landley.net>
8 * This program is licensed under the GNU General Public license (GPL)
9 * version 2 or later, see http://www.fsf.org/licensing/licenses/gpl.html
10 * or the file "LICENSE" in the busybox source tarball for the full text.
18 #define OPTION_STRING "flDnravd"
21 #define OPT_DONTFREELOOP 4
23 #define OPT_REMOUNT 16
24 #define OPT_ALL (ENABLE_FEATURE_UMOUNT_ALL ? 32 : 0)
26 int umount_main(int argc, char **argv)
29 char path[2*PATH_MAX];
32 int status = EXIT_SUCCESS;
37 struct mtab_list *next;
40 /* Parse any options */
42 opt = bb_getopt_ulflags(argc, argv, OPTION_STRING);
47 doForce = MAX((opt & OPT_FORCE), (opt & OPT_LAZY));
49 /* Get a list of mount points from mtab. We read them all in now mostly
50 * for umount -a (so we don't have to worry about the list changing while
51 * we iterate over it, or about getting stuck in a loop on the same failing
52 * entry. Notice that this also naturally reverses the list so that -a
53 * umounts the most recent entries first. */
57 /* If we're umounting all, then m points to the start of the list and
58 * the argument list should be empty (which will match all). */
60 if (!(fp = setmntent(bb_path_mtab_file, "r"))) {
62 bb_error_msg_and_die("cannot open %s", bb_path_mtab_file);
64 while (getmntent_r(fp,&me,path,sizeof(path))) {
65 m = xmalloc(sizeof(struct mtab_list));
67 m->device = xstrdup(me.mnt_fsname);
68 m->dir = xstrdup(me.mnt_dir);
74 /* If we're not mounting all, we need at least one argument. */
75 if (!(opt & OPT_ALL)) {
77 if (!argc) bb_show_usage();
80 // Loop through everything we're supposed to umount, and do so.
85 // Do we already know what to umount this time through the loop?
86 if (m) safe_strncpy(path, m->dir, PATH_MAX);
87 // For umount -a, end of mtab means time to exit.
88 else if (opt & OPT_ALL) break;
89 // Get next command line argument (and look it up in mtab list)
90 else if (!argc--) break;
93 realpath(zapit, path);
94 for (m = mtl; m; m = m->next)
95 if (!strcmp(path, m->dir) || !strcmp(path, m->device))
98 // If we couldn't find this sucker in /etc/mtab, punt by passing our
99 // command line argument straight to the umount syscall. Otherwise,
100 // umount the directory even if we were given the block device.
101 if (m) zapit = m->dir;
103 // Let's ask the thing nicely to unmount.
104 curstat = umount(zapit);
106 // Force the unmount, if necessary.
107 if (curstat && doForce) {
108 curstat = umount2(zapit, doForce);
110 bb_error_msg_and_die("forced umount of %s failed!", zapit);
113 // If still can't umount, maybe remount read-only?
114 if (curstat && (opt & OPT_REMOUNT) && errno == EBUSY && m) {
115 curstat = mount(m->device, zapit, NULL, MS_REMOUNT|MS_RDONLY, NULL);
116 bb_error_msg(curstat ? "cannot remount %s read-only" :
117 "%s busy - remounted read-only", m->device);
121 status = EXIT_FAILURE;
122 bb_perror_msg("cannot umount %s", zapit);
124 /* De-allocate the loop device. This ioctl should be ignored on
125 * any non-loop block devices. */
126 if (ENABLE_FEATURE_MOUNT_LOOP && !(opt & OPT_DONTFREELOOP) && m)
128 if (ENABLE_FEATURE_MTAB_SUPPORT && !(opt & OPT_NO_MTAB) && m)
132 // Find next matching mtab entry for -a or umount /dev
133 // Note this means that "umount /dev/blah" will unmount all instances
134 // of /dev/blah, not just the most recent.
135 while (m && (m = m->next))
136 if ((opt & OPT_ALL) || !strcmp(path,m->device))
140 // Free mtab list if necessary
142 if (ENABLE_FEATURE_CLEAN_UP) {