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/* vi: set sw=4 ts=4: */
/*
* Mini umount implementation for busybox
*
* Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
* Copyright (C) 2005 by Rob Landley <rob@landley.net>
*
* Licensed under GPL version 2, see file LICENSE in this tarball for details.
*/
#include <mntent.h>
#include <getopt.h>
#include "libbb.h"
#define OPTION_STRING "flDnravdt:"
#define OPT_FORCE 1
#define OPT_LAZY 2
#define OPT_DONTFREELOOP 4
#define OPT_NO_MTAB 8
#define OPT_REMOUNT 16
#define OPT_ALL (ENABLE_FEATURE_UMOUNT_ALL ? 32 : 0)
int umount_main(int argc, char **argv);
int umount_main(int argc, char **argv)
{
int doForce;
char path[2*PATH_MAX];
struct mntent me;
FILE *fp;
char *fstype = 0;
int status = EXIT_SUCCESS;
unsigned opt;
struct mtab_list {
char *dir;
char *device;
struct mtab_list *next;
} *mtl, *m;
/* Parse any options */
opt = getopt32(argc, argv, OPTION_STRING, &fstype);
argc -= optind;
argv += optind;
doForce = MAX((opt & OPT_FORCE), (opt & OPT_LAZY));
/* Get a list of mount points from mtab. We read them all in now mostly
* for umount -a (so we don't have to worry about the list changing while
* we iterate over it, or about getting stuck in a loop on the same failing
* entry. Notice that this also naturally reverses the list so that -a
* umounts the most recent entries first. */
m = mtl = 0;
/* If we're umounting all, then m points to the start of the list and
* the argument list should be empty (which will match all). */
fp = setmntent(bb_path_mtab_file, "r");
if (!fp) {
if (opt & OPT_ALL)
bb_error_msg_and_die("cannot open %s", bb_path_mtab_file);
} else {
while (getmntent_r(fp, &me, path, sizeof(path))) {
/* Match fstype if passed */
if (fstype && match_fstype(&me, fstype))
continue;
m = xmalloc(sizeof(struct mtab_list));
m->next = mtl;
m->device = xstrdup(me.mnt_fsname);
m->dir = xstrdup(me.mnt_dir);
mtl = m;
}
endmntent(fp);
}
/* If we're not umounting all, we need at least one argument. */
if (!(opt & OPT_ALL) && !fstype) {
m = 0;
if (!argc) bb_show_usage();
}
// Loop through everything we're supposed to umount, and do so.
for (;;) {
int curstat;
char *zapit = *argv;
// Do we already know what to umount this time through the loop?
if (m) safe_strncpy(path, m->dir, PATH_MAX);
// For umount -a, end of mtab means time to exit.
else if (opt & OPT_ALL) break;
// Get next command line argument (and look it up in mtab list)
else if (!argc--) break;
else {
argv++;
realpath(zapit, path);
for (m = mtl; m; m = m->next)
if (!strcmp(path, m->dir) || !strcmp(path, m->device))
break;
}
// If we couldn't find this sucker in /etc/mtab, punt by passing our
// command line argument straight to the umount syscall. Otherwise,
// umount the directory even if we were given the block device.
if (m) zapit = m->dir;
// Let's ask the thing nicely to unmount.
curstat = umount(zapit);
// Force the unmount, if necessary.
if (curstat && doForce) {
curstat = umount2(zapit, doForce);
if (curstat)
bb_error_msg("forced umount of %s failed!", zapit);
}
// If still can't umount, maybe remount read-only?
if (curstat && (opt & OPT_REMOUNT) && errno == EBUSY && m) {
curstat = mount(m->device, zapit, NULL, MS_REMOUNT|MS_RDONLY, NULL);
bb_error_msg(curstat ? "cannot remount %s read-only" :
"%s busy - remounted read-only", m->device);
}
if (curstat) {
status = EXIT_FAILURE;
bb_perror_msg("cannot umount %s", zapit);
} else {
/* De-allocate the loop device. This ioctl should be ignored on
* any non-loop block devices. */
if (ENABLE_FEATURE_MOUNT_LOOP && !(opt & OPT_DONTFREELOOP) && m)
del_loop(m->device);
if (ENABLE_FEATURE_MTAB_SUPPORT && !(opt & OPT_NO_MTAB) && m)
erase_mtab(m->dir);
}
// Find next matching mtab entry for -a or umount /dev
// Note this means that "umount /dev/blah" will unmount all instances
// of /dev/blah, not just the most recent.
while (m && (m = m->next))
if ((opt & OPT_ALL) || !strcmp(path, m->device))
break;
}
// Free mtab list if necessary
if (ENABLE_FEATURE_CLEAN_UP) {
while (mtl) {
m = mtl->next;
free(mtl->device);
free(mtl->dir);
free(mtl);
mtl = m;
}
}
return status;
}
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