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.
20 #include <sys/mount.h>
24 #define OPTION_STRING "flDnrvad"
27 #define OPT_DONTFREELOOP 4
29 #define OPT_REMOUNT 16
30 #define OPT_IGNORED 32 // -v is ignored
31 #define OPT_ALL (ENABLE_FEATURE_UMOUNT_ALL ? 64 : 0)
33 int umount_main(int argc, char **argv)
36 char path[2*PATH_MAX];
39 int status = EXIT_SUCCESS;
44 struct mtab_list *next;
47 /* Parse any options */
49 opt = bb_getopt_ulflags(argc, argv, OPTION_STRING);
54 doForce = MAX((opt & OPT_FORCE), (opt & OPT_LAZY));
56 /* Get a list of mount points from mtab. We read them all in now mostly
57 * for umount -a (so we don't have to worry about the list changing while
58 * we iterate over it, or about getting stuck in a loop on the same failing
59 * entry. Notice that this also naturally reverses the list so that -a
60 * umounts the most recent entries first. */
64 /* If we're umounting all, then m points to the start of the list and
65 * the argument list should be empty (which will match all). */
67 if (!(fp = setmntent(bb_path_mtab_file, "r"))) {
69 bb_error_msg_and_die("Cannot open %s", bb_path_mtab_file);
70 } else while (getmntent_r(fp,&me,path,sizeof(path))) {
71 m = xmalloc(sizeof(struct mtab_list));
73 m->device = bb_xstrdup(me.mnt_fsname);
74 m->dir = bb_xstrdup(me.mnt_dir);
79 /* If we're not mounting all, we need at least one argument. */
80 if (!(opt & OPT_ALL)) {
82 if (!argc) bb_show_usage();
87 // Loop through everything we're supposed to umount, and do so.
91 // Do we already know what to umount this time through the loop?
92 if (m) safe_strncpy(path, m->dir, PATH_MAX);
93 // For umount -a, end of mtab means time to exit.
94 else if (opt & OPT_ALL) break;
95 // Get next command line argument (and look it up in mtab list)
96 else if (!argc--) break;
98 realpath(*argv++, path);
99 for (m = mtl; m; m = m->next)
100 if (!strcmp(path, m->dir) || !strcmp(path, m->device))
104 // Let's ask the thing nicely to unmount.
105 curstat = umount(path);
107 // Force the unmount, if necessary.
108 if (curstat && doForce) {
109 curstat = umount2(path, doForce);
111 bb_error_msg_and_die("forced umount of %s failed!", path);
114 // If still can't umount, maybe remount read-only?
115 if (curstat && (opt & OPT_REMOUNT) && errno == EBUSY && m) {
116 curstat = mount(m->device, path, NULL, MS_REMOUNT|MS_RDONLY, NULL);
117 bb_error_msg(curstat ? "Cannot remount %s read-only" :
118 "%s busy - remounted read-only", m->device);
121 /* De-allocate the loop device. This ioctl should be ignored on any
122 * non-loop block devices. */
123 if (ENABLE_FEATURE_MOUNT_LOOP && !(opt & OPT_DONTFREELOOP) && m)
127 /* Yes, the ENABLE is redundant here, but the optimizer for ARM
128 * can't do simple constant propagation in local variables... */
129 if(ENABLE_FEATURE_MTAB_SUPPORT && !(opt & OPT_NO_MTAB) && m)
131 status = EXIT_FAILURE;
132 bb_perror_msg("Couldn't umount %s", path);
134 // Find next matching mtab entry for -a or umount /dev
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) {