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-rw-r--r--util-linux/umount.c370
1 files changed, 107 insertions, 263 deletions
diff --git a/util-linux/umount.c b/util-linux/umount.c
index 21c2e6e4d..6de71b4ab 100644
--- a/util-linux/umount.c
+++ b/util-linux/umount.c
@@ -3,20 +3,11 @@
* Mini umount implementation for busybox
*
* Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.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
+ * Copyright (C) 2005 by Rob Landley <rob@landley.net>
+ *
+ * This program is licensed under the GNU General Public license (GPL)
+ * version 2 or later, see http://www.fsf.org/licensing/licenses/gpl.html
+ * or the file "LICENSE" in the busybox source tarball for the full text.
*
*/
@@ -26,273 +17,126 @@
#include <errno.h>
#include <string.h>
#include <stdlib.h>
+#include <sys/mount.h>
#include "busybox.h"
-/* Teach libc5 about realpath -- it includes it but the
- * prototype is missing... */
-#if (__GLIBC__ <= 2) && (__GLIBC_MINOR__ < 1)
-extern char *realpath(const char *path, char *resolved_path);
-#endif
-
-static const int MNT_FORCE = 1;
-static const int MS_MGC_VAL = 0xc0ed0000; /* Magic number indicatng "new" flags */
-static const int MS_REMOUNT = 32; /* Alter flags of a mounted FS. */
-static const int MS_RDONLY = 1; /* Mount read-only. */
-
-extern int mount (__const char *__special_file, __const char *__dir,
- __const char *__fstype, unsigned long int __rwflag,
- __const void *__data);
-extern int umount (__const char *__special_file);
-extern int umount2 (__const char *__special_file, int __flags);
-
-struct _mtab_entry_t {
- char *device;
- char *mountpt;
- struct _mtab_entry_t *next;
-};
-
-static struct _mtab_entry_t *mtab_cache = NULL;
-
-
-
-#if defined CONFIG_FEATURE_MOUNT_FORCE
-static int doForce = FALSE;
-#endif
-#if defined CONFIG_FEATURE_MOUNT_LOOP
-static int freeLoop = TRUE;
-#endif
-#if defined CONFIG_FEATURE_MTAB_SUPPORT
-static int useMtab = TRUE;
-#endif
-static int umountAll = FALSE;
-static int doRemount = FALSE;
-
-
-
-/* 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
- */
-static void mtab_read(void)
+extern int umount_main(int argc, char **argv)
{
- struct _mtab_entry_t *entry = NULL;
- struct mntent *e;
+ int doForce = 0;
+ int freeLoop = ENABLE_FEATURE_MOUNT_LOOP;
+ int useMtab = ENABLE_FEATURE_MTAB_SUPPORT;
+ int umountAll = FALSE;
+ int doRemount = FALSE;
+ char path[2*PATH_MAX];
+ struct mntent me;
FILE *fp;
-
- if (mtab_cache != NULL)
- return;
-
- if ((fp = setmntent(bb_path_mtab_file, "r")) == NULL) {
- bb_error_msg("Cannot open %s", bb_path_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);
-}
-
-static char *mtab_getinfo(const char *match, const char which)
-{
- struct _mtab_entry_t *cur = mtab_cache;
-
- while (cur) {
- if (strcmp(cur->mountpt, match) == 0 ||
- strcmp(cur->device, match) == 0) {
- if (which == MTAB_GETMOUNTPT) {
- return cur->mountpt;
- } else {
-#if !defined CONFIG_FEATURE_MTAB_SUPPORT
- if (strcmp(cur->device, "rootfs") == 0) {
- continue;
- } else 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 */
- cur->device = find_real_root_device_name();
- }
-#endif
- return cur->device;
- }
+ int status=EXIT_SUCCESS;
+ struct mtab_list {
+ char *dir;
+ char *device;
+ struct mtab_list *next;
+ } *mtl, *m;
+
+ if(argc < 2) bb_show_usage();
+
+ /* Parse any options */
+ while (--argc > 0 && **(++argv) == '-') {
+ while (*++(*argv)) {
+ if(**argv=='a') umountAll = TRUE;
+ else if(ENABLE_FEATURE_MOUNT_LOOP && **argv=='D') freeLoop = FALSE;
+ else if(ENABLE_FEATURE_MTAB_SUPPORT && **argv=='n') useMtab = FALSE;
+ else if(**argv=='f') doForce = 1; // MNT_FORCE
+ else if(**argv=='l') doForce = 2; // MNT_DETACH
+ else if(**argv=='r') doRemount = TRUE;
+ else if(**argv=='v');
+ else bb_show_usage();
}
- cur = cur->next;
}
- return NULL;
-}
-
-static char *mtab_next(void **iter)
-{
- char *mp;
- if (iter == NULL || *iter == NULL)
- return NULL;
- mp = ((struct _mtab_entry_t *) (*iter))->mountpt;
- *iter = (void *) ((struct _mtab_entry_t *) (*iter))->next;
- return mp;
-}
-
-static char *mtab_first(void **iter)
-{
- struct _mtab_entry_t *mtab_iter;
-
- if (!iter)
- return NULL;
- mtab_iter = mtab_cache;
- *iter = (void *) mtab_iter;
- return mtab_next(iter);
-}
-
-/* Don't bother to clean up, since exit() does that
- * automagically, so we can save a few bytes */
-#ifdef CONFIG_FEATURE_CLEAN_UP
-static void mtab_free(void)
-{
- struct _mtab_entry_t *this, *next;
-
- this = mtab_cache;
- while (this) {
- next = this->next;
- free(this->device);
- free(this->mountpt);
- free(this);
- this = next;
+ /* 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(!(fp = setmntent(bb_path_mtab_file, "r")))
+ bb_error_msg_and_die("Cannot open %s", bb_path_mtab_file);
+ while (getmntent_r(fp,&me,path,sizeof(path))) {
+ m=xmalloc(sizeof(struct mtab_list));
+ m->next=mtl;
+ m->device=bb_xstrdup(me.mnt_fsname);
+ m->dir=bb_xstrdup(me.mnt_dir);
+ mtl=m;
}
-}
-#endif
-
-static int do_umount(const char *name)
-{
- int status;
- char *blockDevice = mtab_getinfo(name, MTAB_GETDEVICE);
-
- if (blockDevice && strcmp(blockDevice, name) == 0)
- name = mtab_getinfo(blockDevice, MTAB_GETMOUNTPT);
-
- status = umount(name);
+ endmntent(fp);
-#if defined CONFIG_FEATURE_MOUNT_LOOP
- if (freeLoop && blockDevice != NULL && !strncmp("/dev/loop", blockDevice, 9))
- /* this was a loop device, delete it */
- del_loop(blockDevice);
-#endif
-#if defined CONFIG_FEATURE_MOUNT_FORCE
- if (status != 0 && doForce) {
- status = umount2(blockDevice, MNT_FORCE);
- if (status != 0) {
- bb_error_msg_and_die("forced umount of %s failed!", blockDevice);
- }
- }
-#endif
- if (status != 0 && doRemount && errno == EBUSY) {
- status = mount(blockDevice, name, NULL,
- MS_MGC_VAL | MS_REMOUNT | MS_RDONLY, NULL);
- if (status == 0) {
- bb_error_msg("%s busy - remounted read-only", blockDevice);
- } else {
- bb_error_msg("Cannot remount %s read-only", blockDevice);
+ /* 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(!umountAll) m=0;
+
+ // Loop through everything we're supposed to umount, and do so.
+ for(;;) {
+ int curstat;
+
+ // Do we alrady know what to umount this time through the loop?
+ if(m) safe_strncpy(path,m->dir,PATH_MAX);
+ // For umountAll, end of mtab means time to exit.
+ else if(umountAll) break;
+ // Get next command line argument (and look it up in mtab list)
+ else if(!argc--) break;
+ else {
+ // Get next command line argument (and look it up in mtab list)
+ realpath(*argv++, path);
+ for(m = mtl; m; m = m->next)
+ if(!strcmp(path, m->dir) || !strcmp(path, m->device))
+ break;
}
- }
- if (status == 0) {
-#if defined CONFIG_FEATURE_MTAB_SUPPORT
- if (useMtab)
- erase_mtab(name);
-#endif
- return (TRUE);
- }
- return (FALSE);
-}
-static int umount_all(void)
-{
- int status = TRUE;
- char *mountpt;
- void *iter;
+ // Let's ask the thing nicely to unmount.
+ curstat = umount(path);
- for (mountpt = mtab_first(&iter); mountpt; mountpt = mtab_next(&iter)) {
- /* Never umount /proc on a umount -a */
- if (strstr(mountpt, "proc")!= NULL)
- continue;
- if (!do_umount(mountpt)) {
- /* Don't bother retrying the umount on busy devices */
- if (errno == EBUSY) {
- bb_perror_msg("%s", mountpt);
- status = FALSE;
- continue;
- }
- if (!do_umount(mountpt)) {
- printf("Couldn't umount %s on %s: %s\n",
- mountpt, mtab_getinfo(mountpt, MTAB_GETDEVICE),
- strerror(errno));
- status = FALSE;
- }
+ // Force the unmount, if necessary.
+ if(curstat && doForce) {
+ curstat = umount2(path, doForce);
+ if(curstat)
+ bb_error_msg_and_die("forced umount of %s failed!", path);
}
- }
- return (status);
-}
-extern int umount_main(int argc, char **argv)
-{
- char path[PATH_MAX], result = 0;
+ // If still can't umount, maybe remount read-only?
+ if (curstat && doRemount && errno == EBUSY && m) {
+ curstat = mount(m->device, path, NULL, MS_REMOUNT|MS_RDONLY, NULL);
+ bb_error_msg(curstat ? "Cannot remount %s read-only" :
+ "%s busy - remounted read-only", m->device);
+ }
- if (argc < 2) {
- bb_show_usage();
- }
-#ifdef CONFIG_FEATURE_CLEAN_UP
- atexit(mtab_free);
-#endif
+ /* De-allcate the loop device. This ioctl should be ignored on any
+ * non-loop block devices. */
+ if(ENABLE_FEATURE_MOUNT_LOOP && freeLoop && m)
+ del_loop(m->device);
- /* Parse any options */
- while (--argc > 0 && **(++argv) == '-') {
- while (*++(*argv))
- switch (**argv) {
- case 'a':
- umountAll = TRUE;
- break;
-#if defined CONFIG_FEATURE_MOUNT_LOOP
- case 'l':
- freeLoop = FALSE;
- break;
-#endif
-#ifdef CONFIG_FEATURE_MTAB_SUPPORT
- case 'n':
- useMtab = FALSE;
- break;
-#endif
-#ifdef CONFIG_FEATURE_MOUNT_FORCE
- case 'f':
- doForce = TRUE;
- break;
-#endif
- case 'r':
- doRemount = TRUE;
- break;
- case 'v':
- break; /* ignore -v */
- default:
- bb_show_usage();
- }
+ if(curstat) {
+ if(useMtab && m) erase_mtab(m->dir);
+ status = EXIT_FAILURE;
+ bb_perror_msg("Couldn't umount %s\n", path);
+ }
+ // Find next matching mtab entry for -a or umount /dev
+ while(m && (m = m->next))
+ if(umountAll || !strcmp(path,m->device))
+ break;
}
- mtab_read();
- if (umountAll) {
- if (umount_all())
- return EXIT_SUCCESS;
- else
- return EXIT_FAILURE;
+ // 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;
+ }
}
- do {
- if (realpath(*argv, path) != NULL)
- if (do_umount(path))
- continue;
- bb_perror_msg("%s", path);
- result++;
- } while (--argc > 0 && ++argv);
- return result;
+ return status;
}
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