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 #define OPTION_STRING "flDnravdt:"
18 #define OPT_DONTFREELOOP 4
20 #define OPT_REMOUNT 16
21 #define OPT_ALL (ENABLE_FEATURE_UMOUNT_ALL ? 32 : 0)
23 int umount_main(int argc, char **argv);
24 int umount_main(int argc, char **argv)
27 char path[2*PATH_MAX];
31 int status = EXIT_SUCCESS;
36 struct mtab_list *next;
39 /* Parse any options */
41 opt = getopt32(argc, argv, OPTION_STRING, &fstype);
46 doForce = MAX((opt & OPT_FORCE), (opt & OPT_LAZY));
48 /* Get a list of mount points from mtab. We read them all in now mostly
49 * for umount -a (so we don't have to worry about the list changing while
50 * we iterate over it, or about getting stuck in a loop on the same failing
51 * entry. Notice that this also naturally reverses the list so that -a
52 * umounts the most recent entries first. */
56 /* If we're umounting all, then m points to the start of the list and
57 * the argument list should be empty (which will match all). */
59 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 /* Match fstype if passed */
66 if (fstype && match_fstype(&me, fstype))
68 m = xmalloc(sizeof(struct mtab_list));
70 m->device = xstrdup(me.mnt_fsname);
71 m->dir = xstrdup(me.mnt_dir);
77 /* If we're not umounting all, we need at least one argument. */
78 if (!(opt & OPT_ALL) && !fstype) {
80 if (!argc) bb_show_usage();
83 // Loop through everything we're supposed to umount, and do so.
88 // Do we already know what to umount this time through the loop?
89 if (m) safe_strncpy(path, m->dir, PATH_MAX);
90 // For umount -a, end of mtab means time to exit.
91 else if (opt & OPT_ALL) break;
92 // Get next command line argument (and look it up in mtab list)
93 else if (!argc--) break;
96 realpath(zapit, path);
97 for (m = mtl; m; m = m->next)
98 if (!strcmp(path, m->dir) || !strcmp(path, m->device))
101 // If we couldn't find this sucker in /etc/mtab, punt by passing our
102 // command line argument straight to the umount syscall. Otherwise,
103 // umount the directory even if we were given the block device.
104 if (m) zapit = m->dir;
106 // Let's ask the thing nicely to unmount.
107 curstat = umount(zapit);
109 // Force the unmount, if necessary.
110 if (curstat && doForce) {
111 curstat = umount2(zapit, doForce);
113 bb_error_msg("forced umount of %s failed!", zapit);
116 // If still can't umount, maybe remount read-only?
117 if (curstat && (opt & OPT_REMOUNT) && errno == EBUSY && m) {
118 curstat = mount(m->device, zapit, NULL, MS_REMOUNT|MS_RDONLY, NULL);
119 bb_error_msg(curstat ? "cannot remount %s read-only" :
120 "%s busy - remounted read-only", m->device);
124 status = EXIT_FAILURE;
125 bb_perror_msg("cannot umount %s", zapit);
127 /* De-allocate the loop device. This ioctl should be ignored on
128 * any non-loop block devices. */
129 if (ENABLE_FEATURE_MOUNT_LOOP && !(opt & OPT_DONTFREELOOP) && m)
131 if (ENABLE_FEATURE_MTAB_SUPPORT && !(opt & OPT_NO_MTAB) && m)
135 // Find next matching mtab entry for -a or umount /dev
136 // Note this means that "umount /dev/blah" will unmount all instances
137 // of /dev/blah, not just the most recent.
138 while (m && (m = m->next))
139 if ((opt & OPT_ALL) || !strcmp(path, m->device))
143 // Free mtab list if necessary
145 if (ENABLE_FEATURE_CLEAN_UP) {