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 * Licensed under GPL version 2, see file LICENSE in this tarball for details.
15 /* ignored: -v -d -t -i */
16 #define OPTION_STRING "flDnra" "vdt:i"
17 #define OPT_FORCE (1 << 0)
18 #define OPT_LAZY (1 << 1)
19 #define OPT_DONTFREELOOP (1 << 2)
20 #define OPT_NO_MTAB (1 << 3)
21 #define OPT_REMOUNT (1 << 4)
22 #define OPT_ALL (ENABLE_FEATURE_UMOUNT_ALL ? (1 << 5) : 0)
24 int umount_main(int argc, char **argv);
25 int umount_main(int argc, char **argv)
28 char path[2*PATH_MAX];
32 int status = EXIT_SUCCESS;
37 struct mtab_list *next;
40 /* Parse any options */
42 opt = getopt32(argv, OPTION_STRING, &fstype);
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 fp = setmntent(bb_path_mtab_file, "r");
63 bb_error_msg_and_die("cannot open %s", bb_path_mtab_file);
65 while (getmntent_r(fp, &me, path, sizeof(path))) {
66 /* Match fstype if passed */
67 if (fstype && match_fstype(&me, fstype))
69 m = xmalloc(sizeof(struct mtab_list));
71 m->device = xstrdup(me.mnt_fsname);
72 m->dir = xstrdup(me.mnt_dir);
78 /* If we're not umounting all, we need at least one argument. */
79 if (!(opt & OPT_ALL) && !fstype) {
85 // Loop through everything we're supposed to umount, and do so.
90 // Do we already know what to umount this time through the loop?
92 safe_strncpy(path, m->dir, PATH_MAX);
93 // For umount -a, end of mtab means time to exit.
94 else if (opt & OPT_ALL)
96 // Get next command line argument (and look it up in mtab list)
101 realpath(zapit, path);
102 for (m = mtl; m; m = m->next)
103 if (!strcmp(path, m->dir) || !strcmp(path, m->device))
106 // If we couldn't find this sucker in /etc/mtab, punt by passing our
107 // command line argument straight to the umount syscall. Otherwise,
108 // umount the directory even if we were given the block device.
109 if (m) zapit = m->dir;
111 // Let's ask the thing nicely to unmount.
112 curstat = umount(zapit);
114 // Force the unmount, if necessary.
115 if (curstat && doForce) {
116 curstat = umount2(zapit, doForce);
118 bb_error_msg("forced umount of %s failed!", zapit);
121 // If still can't umount, maybe remount read-only?
122 if (curstat && (opt & OPT_REMOUNT) && errno == EBUSY && m) {
123 curstat = mount(m->device, zapit, NULL, MS_REMOUNT|MS_RDONLY, NULL);
124 bb_error_msg(curstat ? "cannot remount %s read-only" :
125 "%s busy - remounted read-only", m->device);
129 status = EXIT_FAILURE;
130 bb_perror_msg("cannot umount %s", zapit);
132 /* De-allocate the loop device. This ioctl should be ignored on
133 * any non-loop block devices. */
134 if (ENABLE_FEATURE_MOUNT_LOOP && !(opt & OPT_DONTFREELOOP) && m)
136 if (ENABLE_FEATURE_MTAB_SUPPORT && !(opt & OPT_NO_MTAB) && m)
140 // Find next matching mtab entry for -a or umount /dev
141 // Note this means that "umount /dev/blah" will unmount all instances
142 // of /dev/blah, not just the most recent.
143 while (m && (m = m->next))
144 if ((opt & OPT_ALL) || !strcmp(path, m->device))
148 // Free mtab list if necessary
150 if (ENABLE_FEATURE_CLEAN_UP) {