/*
* Mini umount implementation for busybox
*
+ * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
+ * Copyright (C) 2005 by Rob Landley <rob@landley.net>
*
- * Copyright (C) 1999 by Lineo, inc.
- * Written by Erik Andersen <andersen@lineo.com>, <andersee@debian.org>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
- *
+ * Licensed under GPL version 2, see file LICENSE in this tarball for details.
*/
-#include "internal.h"
-#include <stdio.h>
-#include <sys/mount.h>
#include <mntent.h>
-#include <errno.h>
-
-
-static const char umount_usage[] =
- "umount [flags] filesystem|directory\n\n"
- "Flags:\n" "\t-a:\tUnmount all file systems"
-#ifdef BB_MTAB
- " in /etc/mtab\n\t-n:\tDon't erase /etc/mtab entries\n"
-#else
- "\n"
-#endif
-#ifdef BB_FEATURE_REMOUNT
- "\t-r:\tTry to remount devices as read-only if mount is busy\n"
-#endif
-#if defined BB_FEATURE_MOUNT_LOOP
- "\t-f:\tDo not free loop device (if a loop device has been used)\n"
-#endif
-;
-
-struct _mtab_entry_t {
- char *device;
- char *mountpt;
- struct _mtab_entry_t *next;
-};
-
-static struct _mtab_entry_t *mtab_cache = NULL;
-
-
-
-#if defined BB_FEATURE_MOUNT_LOOP
-static int freeLoop = TRUE;
-#endif
-static int useMtab = TRUE;
-static int umountAll = FALSE;
-#if defined BB_FEATURE_REMOUNT
-static int doRemount = FALSE;
-#endif
-extern const char mtab_file[]; /* Defined in utility.c */
-
-
-
-/* These functions are here because the getmntent functions do not appear
- * to be re-entrant, which leads to all sorts of problems when we try to
- * use them recursively - randolph
- *
- * TODO: Perhaps switch to using Glibc's getmntent_r
- * -Erik
- */
-void mtab_read(void)
+#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)
{
- struct _mtab_entry_t *entry = NULL;
- struct mntent *e;
+ 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;
- if (mtab_cache != NULL)
- return;
+ /* Parse any options */
- if ((fp = setmntent(mtab_file, "r")) == NULL) {
- fprintf(stderr, "Cannot open %s\n", mtab_file);
- return;
- }
- while ((e = getmntent(fp))) {
- entry = xmalloc(sizeof(struct _mtab_entry_t));
- entry->device = strdup(e->mnt_fsname);
- entry->mountpt = strdup(e->mnt_dir);
- entry->next = mtab_cache;
- mtab_cache = entry;
- }
- endmntent(fp);
-}
+ opt = getopt32(argc, argv, OPTION_STRING, &fstype);
-char *mtab_getinfo(const char *match, const char which)
-{
- struct _mtab_entry_t *cur = mtab_cache;
+ argc -= optind;
+ argv += optind;
- while (cur) {
- if (strcmp(cur->mountpt, match) == 0 ||
- strcmp(cur->device, match) == 0) {
- if (which == MTAB_GETMOUNTPT) {
- return cur->mountpt;
- } else {
-#if !defined BB_MTAB
- if (strcmp(cur->device, "/dev/root") == 0) {
- /* Adjusts device to be the real root device,
- * or leaves device alone if it can't find it */
- find_real_root_device_name( cur->device);
- return ( cur->device);
- }
-#endif
- return cur->device;
- }
- }
- cur = cur->next;
- }
- return NULL;
-}
+ doForce = MAX((opt & OPT_FORCE), (opt & OPT_LAZY));
-char *mtab_first(void **iter)
-{
- struct _mtab_entry_t *mtab_iter;
+ /* 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. */
- if (!iter)
- return NULL;
- mtab_iter = mtab_cache;
- *iter = (void *) mtab_iter;
- return mtab_next(iter);
-}
+ m = mtl = 0;
-char *mtab_next(void **iter)
-{
- char *mp;
+ /* 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). */
- if (iter == NULL || *iter == NULL)
- return NULL;
- mp = ((struct _mtab_entry_t *) (*iter))->mountpt;
- *iter = (void *) ((struct _mtab_entry_t *) (*iter))->next;
- return mp;
-}
-
-void mtab_free(void)
-{
- struct _mtab_entry_t *this, *next;
-
- this = mtab_cache;
- while (this) {
- next = this->next;
- if (this->device)
- free(this->device);
- if (this->mountpt)
- free(this->mountpt);
- free(this);
- this = next;
+ 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);
}
-}
-static int do_umount(const char *name, int useMtab)
-{
- int status;
- char *blockDevice = mtab_getinfo(name, MTAB_GETDEVICE);
+ /* If we're not umounting all, we need at least one argument. */
+ if (!(opt & OPT_ALL) && !fstype) {
+ m = 0;
+ if (!argc) bb_show_usage();
+ }
- if (blockDevice && strcmp(blockDevice, name) == 0)
- name = mtab_getinfo(blockDevice, MTAB_GETMOUNTPT);
+ // 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);
+ }
- status = umount(name);
+ // 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 defined BB_FEATURE_MOUNT_LOOP
- if (freeLoop == TRUE && blockDevice != NULL && !strncmp("/dev/loop", blockDevice, 9))
- /* this was a loop device, delete it */
- del_loop(blockDevice);
-#endif
-#if defined BB_FEATURE_REMOUNT
- if (status != 0 && doRemount == TRUE && errno == EBUSY) {
- status = mount(blockDevice, name, NULL,
- MS_MGC_VAL | MS_REMOUNT | MS_RDONLY, NULL);
- if (status == 0) {
- fprintf(stderr, "umount: %s busy - remounted read-only\n",
- blockDevice);
- /* TODO: update mtab if BB_MTAB is defined */
+ if (curstat) {
+ status = EXIT_FAILURE;
+ bb_perror_msg("cannot umount %s", zapit);
} else {
- fprintf(stderr, "umount: Cannot remount %s read-only\n",
- blockDevice);
+ /* 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);
}
- }
-#endif
- if (status == 0) {
-#if defined BB_MTAB
- if (useMtab == TRUE)
- erase_mtab(name);
-#endif
- return (TRUE);
- }
- return (FALSE);
-}
-static int umount_all(int useMtab)
-{
- int status = TRUE;
- char *mountpt;
- void *iter;
-
- for (mountpt = mtab_first(&iter); mountpt; mountpt = mtab_next(&iter)) {
- /* Never umount /proc on a umount -a */
- if (strstr(mountpt, "proc")!= NULL)
- continue;
- status = do_umount(mountpt, useMtab);
- if (status != 0) {
- /* Don't bother retrying the umount on busy devices */
- if (errno == EBUSY) {
- perror(mountpt);
- continue;
- }
- status = do_umount(mountpt, useMtab);
- if (status != 0) {
- printf("Couldn't umount %s on %s: %s\n",
- mountpt, mtab_getinfo(mountpt, MTAB_GETDEVICE),
- strerror(errno));
- }
- }
+ // 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;
}
- return (status);
-}
-extern int umount_main(int argc, char **argv)
-{
- if (argc < 2) {
- usage(umount_usage);
- }
+ // Free mtab list if necessary
- /* Parse any options */
- while (--argc > 0 && **(++argv) == '-') {
- while (*++(*argv))
- switch (**argv) {
- case 'a':
- umountAll = TRUE;
- break;
-#if defined BB_FEATURE_MOUNT_LOOP
- case 'f':
- freeLoop = FALSE;
- break;
-#endif
-#ifdef BB_MTAB
- case 'n':
- useMtab = FALSE;
- break;
-#endif
-#ifdef BB_FEATURE_REMOUNT
- case 'r':
- doRemount = TRUE;
- break;
-#endif
- default:
- usage(umount_usage);
- }
+ if (ENABLE_FEATURE_CLEAN_UP) {
+ while (mtl) {
+ m = mtl->next;
+ free(mtl->device);
+ free(mtl->dir);
+ free(mtl);
+ mtl = m;
+ }
}
- mtab_read();
- if (umountAll == TRUE) {
- exit(umount_all(useMtab));
- }
- if (do_umount(*argv, useMtab) == 0)
- exit(TRUE);
- else {
- perror("umount");
- exit(FALSE);
- }
+ return status;
}
-
projects / oweals / busybox.git / blobdiff