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 "flDnravd"
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];
30 int status = EXIT_SUCCESS;
35 struct mtab_list *next;
38 /* Parse any options */
40 opt = getopt32(argc, argv, OPTION_STRING);
45 doForce = MAX((opt & OPT_FORCE), (opt & OPT_LAZY));
47 /* Get a list of mount points from mtab. We read them all in now mostly
48 * for umount -a (so we don't have to worry about the list changing while
49 * we iterate over it, or about getting stuck in a loop on the same failing
50 * entry. Notice that this also naturally reverses the list so that -a
51 * umounts the most recent entries first. */
55 /* If we're umounting all, then m points to the start of the list and
56 * the argument list should be empty (which will match all). */
58 fp = setmntent(bb_path_mtab_file, "r");
61 bb_error_msg_and_die("cannot open %s", bb_path_mtab_file);
63 while (getmntent_r(fp, &me, path, sizeof(path))) {
64 m = xmalloc(sizeof(struct mtab_list));
66 m->device = xstrdup(me.mnt_fsname);
67 m->dir = xstrdup(me.mnt_dir);
73 /* If we're not umounting all, we need at least one argument. */
74 if (!(opt & OPT_ALL)) {
76 if (!argc) bb_show_usage();
79 // Loop through everything we're supposed to umount, and do so.
84 // Do we already know what to umount this time through the loop?
85 if (m) safe_strncpy(path, m->dir, PATH_MAX);
86 // For umount -a, end of mtab means time to exit.
87 else if (opt & OPT_ALL) break;
88 // Get next command line argument (and look it up in mtab list)
89 else if (!argc--) break;
92 realpath(zapit, path);
93 for (m = mtl; m; m = m->next)
94 if (!strcmp(path, m->dir) || !strcmp(path, m->device))
97 // If we couldn't find this sucker in /etc/mtab, punt by passing our
98 // command line argument straight to the umount syscall. Otherwise,
99 // umount the directory even if we were given the block device.
100 if (m) zapit = m->dir;
102 // Let's ask the thing nicely to unmount.
103 curstat = umount(zapit);
105 // Force the unmount, if necessary.
106 if (curstat && doForce) {
107 curstat = umount2(zapit, doForce);
109 bb_error_msg("forced umount of %s failed!", zapit);
112 // If still can't umount, maybe remount read-only?
113 if (curstat && (opt & OPT_REMOUNT) && errno == EBUSY && m) {
114 curstat = mount(m->device, zapit, NULL, MS_REMOUNT|MS_RDONLY, NULL);
115 bb_error_msg(curstat ? "cannot remount %s read-only" :
116 "%s busy - remounted read-only", m->device);
120 status = EXIT_FAILURE;
121 bb_perror_msg("cannot umount %s", zapit);
123 /* De-allocate the loop device. This ioctl should be ignored on
124 * any non-loop block devices. */
125 if (ENABLE_FEATURE_MOUNT_LOOP && !(opt & OPT_DONTFREELOOP) && m)
127 if (ENABLE_FEATURE_MTAB_SUPPORT && !(opt & OPT_NO_MTAB) && m)
131 // Find next matching mtab entry for -a or umount /dev
132 // Note this means that "umount /dev/blah" will unmount all instances
133 // of /dev/blah, not just the most recent.
134 while (m && (m = m->next))
135 if ((opt & OPT_ALL) || !strcmp(path, m->device))
139 // Free mtab list if necessary
141 if (ENABLE_FEATURE_CLEAN_UP) {