busybox/util-linux/umount.c

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/* vi: set sw=4 ts=4: */
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/*
* Mini umount implementation for busybox
*
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*
* Copyright (C) 1999 by Lineo, inc.
* Written by Erik Andersen <andersen@lineo.com>, <andersee@debian.org>
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*
* 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
*
*/
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#include "internal.h"
#include <stdio.h>
#include <sys/mount.h>
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#include <mntent.h>
#include <fstab.h>
#include <errno.h>
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static const char umount_usage[] =
"umount [flags] filesystem|directory\n\n"
"Flags:\n" "\t-a:\tUnmount all file systems"
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#ifdef BB_MTAB
" in /etc/mtab\n\t-n:\tDon't erase /etc/mtab entries\n"
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#else
"\n"
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#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
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;
struct _mtab_entry_t {
char *device;
char *mountpt;
struct _mtab_entry_t *next;
};
static struct _mtab_entry_t *mtab_cache = NULL;
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#if defined BB_FEATURE_MOUNT_LOOP
static int freeLoop = TRUE;
#endif
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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 */
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/* 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)
{
struct _mtab_entry_t *entry = NULL;
struct mntent *e;
FILE *fp;
if (mtab_cache != NULL)
return;
if ((fp = setmntent(mtab_file, "r")) == NULL) {
fprintf(stderr, "Cannot open %s\n", mtab_file);
return;
}
while ((e = getmntent(fp))) {
entry = malloc(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);
}
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 BB_MTAB
if (strcmp(cur->device, "/dev/root") == 0) {
struct fstab *fstabItem;
fstabItem = getfsfile("/");
if (fstabItem != NULL)
return fstabItem->fs_spec;
}
#endif
return cur->device;
}
}
cur = cur->next;
}
return NULL;
}
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);
}
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;
}
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;
}
}
static int do_umount(const char *name, int useMtab)
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{
int status;
char *blockDevice = mtab_getinfo(name, MTAB_GETDEVICE);
if (blockDevice && strcmp(blockDevice, name) == 0)
name = mtab_getinfo(blockDevice, MTAB_GETMOUNTPT);
status = umount(name);
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#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 */
} else {
fprintf(stderr, "umount: Cannot remount %s read-only\n",
blockDevice);
}
}
#endif
if (status == 0) {
#if defined BB_MTAB
if (useMtab == TRUE)
erase_mtab(name);
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#endif
return (TRUE);
}
return (FALSE);
}
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static int umount_all(int useMtab)
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{
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));
}
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}
}
return (status);
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}
extern int umount_main(int argc, char **argv)
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{
if (argc < 2) {
usage(umount_usage);
}
/* 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
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#ifdef BB_MTAB
case 'n':
useMtab = FALSE;
break;
#endif
#ifdef BB_FEATURE_REMOUNT
case 'r':
doRemount = TRUE;
break;
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#endif
default:
usage(umount_usage);
}
}
mtab_read();
if (umountAll == TRUE) {
exit(umount_all(useMtab));
}
if (do_umount(*argv, useMtab) == 0)
exit(TRUE);
else {
perror("umount");
exit(FALSE);
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}
}
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