305 lines
7.0 KiB
C
305 lines
7.0 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* Mini umount implementation for busybox
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*
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*
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* Copyright (C) 1999,2000 by Lineo, inc.
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* Written by Erik Andersen <andersen@lineo.com>, <andersee@debian.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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*/
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#include "internal.h"
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#include <stdio.h>
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#include <mntent.h>
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#include <errno.h>
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#define MNT_FORCE 1
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#define MS_MGC_VAL 0xc0ed0000 /* Magic number indicatng "new" flags */
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#define MS_REMOUNT 32 /* Alter flags of a mounted FS. */
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#define MS_RDONLY 1 /* Mount read-only. */
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extern int mount (__const char *__special_file, __const char *__dir,
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__const char *__fstype, unsigned long int __rwflag,
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__const void *__data);
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extern int umount (__const char *__special_file);
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extern int umount2 (__const char *__special_file, int __flags);
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static const char umount_usage[] =
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"umount [flags] filesystem|directory\n"
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#ifndef BB_FEATURE_TRIVIAL_HELP
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"Unmount file systems\n"
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"\nFlags:\n" "\t-a:\tUnmount all file systems"
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#ifdef BB_MTAB
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" in /etc/mtab\n\t-n:\tDon't erase /etc/mtab entries\n"
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#else
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"\n"
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#endif
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"\t-r:\tTry to remount devices as read-only if mount is busy\n"
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#if defined BB_FEATURE_MOUNT_FORCE
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"\t-f:\tForce filesystem umount (i.e. unreachable NFS server)\n"
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#endif
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#if defined BB_FEATURE_MOUNT_LOOP
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"\t-l:\tDo not free loop device (if a loop device has been used)\n"
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#endif
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#endif
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;
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struct _mtab_entry_t {
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char *device;
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char *mountpt;
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struct _mtab_entry_t *next;
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};
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static struct _mtab_entry_t *mtab_cache = NULL;
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#if defined BB_FEATURE_MOUNT_FORCE
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static int doForce = FALSE;
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#endif
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#if defined BB_FEATURE_MOUNT_LOOP
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static int freeLoop = TRUE;
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#endif
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static int useMtab = TRUE;
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static int umountAll = FALSE;
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static int doRemount = FALSE;
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extern const char mtab_file[]; /* Defined in utility.c */
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/* These functions are here because the getmntent functions do not appear
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* to be re-entrant, which leads to all sorts of problems when we try to
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* use them recursively - randolph
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*
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* TODO: Perhaps switch to using Glibc's getmntent_r
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* -Erik
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*/
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void mtab_read(void)
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{
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struct _mtab_entry_t *entry = NULL;
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struct mntent *e;
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FILE *fp;
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if (mtab_cache != NULL)
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return;
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if ((fp = setmntent(mtab_file, "r")) == NULL) {
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fprintf(stderr, "Cannot open %s\n", mtab_file);
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return;
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}
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while ((e = getmntent(fp))) {
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entry = xmalloc(sizeof(struct _mtab_entry_t));
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entry->device = strdup(e->mnt_fsname);
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entry->mountpt = strdup(e->mnt_dir);
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entry->next = mtab_cache;
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mtab_cache = entry;
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}
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endmntent(fp);
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}
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char *mtab_getinfo(const char *match, const char which)
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{
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struct _mtab_entry_t *cur = mtab_cache;
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while (cur) {
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if (strcmp(cur->mountpt, match) == 0 ||
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strcmp(cur->device, match) == 0) {
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if (which == MTAB_GETMOUNTPT) {
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return cur->mountpt;
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} else {
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#if !defined BB_MTAB
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if (strcmp(cur->device, "/dev/root") == 0) {
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/* Adjusts device to be the real root device,
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* or leaves device alone if it can't find it */
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find_real_root_device_name( cur->device);
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return ( cur->device);
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}
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#endif
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return cur->device;
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}
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}
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cur = cur->next;
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}
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return NULL;
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}
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char *mtab_first(void **iter)
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{
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struct _mtab_entry_t *mtab_iter;
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if (!iter)
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return NULL;
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mtab_iter = mtab_cache;
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*iter = (void *) mtab_iter;
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return mtab_next(iter);
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}
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char *mtab_next(void **iter)
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{
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char *mp;
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if (iter == NULL || *iter == NULL)
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return NULL;
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mp = ((struct _mtab_entry_t *) (*iter))->mountpt;
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*iter = (void *) ((struct _mtab_entry_t *) (*iter))->next;
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return mp;
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}
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/* Don't bother to clean up, since exit() does that
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* automagically, so we can save a few bytes */
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#if 0
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void mtab_free(void)
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{
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struct _mtab_entry_t *this, *next;
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this = mtab_cache;
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while (this) {
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next = this->next;
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if (this->device)
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free(this->device);
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if (this->mountpt)
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free(this->mountpt);
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free(this);
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this = next;
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}
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}
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#endif
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static int do_umount(const char *name, int useMtab)
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{
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int status;
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char *blockDevice = mtab_getinfo(name, MTAB_GETDEVICE);
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if (blockDevice && strcmp(blockDevice, name) == 0)
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name = mtab_getinfo(blockDevice, MTAB_GETMOUNTPT);
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status = umount(name);
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#if defined BB_FEATURE_MOUNT_LOOP
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if (freeLoop == TRUE && blockDevice != NULL && !strncmp("/dev/loop", blockDevice, 9))
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/* this was a loop device, delete it */
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del_loop(blockDevice);
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#endif
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#if defined BB_FEATURE_MOUNT_FORCE
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if (status != 0 && doForce == TRUE) {
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status = umount2(blockDevice, MNT_FORCE);
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if (status != 0) {
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fatalError("umount: forced umount of %s failed!\n", blockDevice);
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}
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}
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#endif
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if (status != 0 && doRemount == TRUE && errno == EBUSY) {
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status = mount(blockDevice, name, NULL,
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MS_MGC_VAL | MS_REMOUNT | MS_RDONLY, NULL);
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if (status == 0) {
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fprintf(stderr, "umount: %s busy - remounted read-only\n",
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blockDevice);
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} else {
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fprintf(stderr, "umount: Cannot remount %s read-only\n",
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blockDevice);
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}
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}
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if (status == 0) {
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#if defined BB_MTAB
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if (useMtab == TRUE)
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erase_mtab(name);
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#endif
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return (TRUE);
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}
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return (FALSE);
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}
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static int umount_all(int useMtab)
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{
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int status = TRUE;
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char *mountpt;
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void *iter;
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for (mountpt = mtab_first(&iter); mountpt; mountpt = mtab_next(&iter)) {
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/* Never umount /proc on a umount -a */
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if (strstr(mountpt, "proc")!= NULL)
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continue;
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status = do_umount(mountpt, useMtab);
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if (status != 0) {
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/* Don't bother retrying the umount on busy devices */
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if (errno == EBUSY) {
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perror(mountpt);
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continue;
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}
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status = do_umount(mountpt, useMtab);
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if (status != 0) {
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printf("Couldn't umount %s on %s: %s\n",
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mountpt, mtab_getinfo(mountpt, MTAB_GETDEVICE),
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strerror(errno));
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}
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}
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}
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return (status);
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}
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extern int umount_main(int argc, char **argv)
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{
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if (argc < 2) {
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usage(umount_usage);
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}
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/* Parse any options */
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while (--argc > 0 && **(++argv) == '-') {
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while (*++(*argv))
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switch (**argv) {
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case 'a':
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umountAll = TRUE;
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break;
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#if defined BB_FEATURE_MOUNT_LOOP
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case 'l':
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freeLoop = FALSE;
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break;
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#endif
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#ifdef BB_MTAB
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case 'n':
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useMtab = FALSE;
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break;
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#endif
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#ifdef BB_FEATURE_MOUNT_FORCE
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case 'f':
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doForce = TRUE;
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break;
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#endif
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case 'r':
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doRemount = TRUE;
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break;
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case 'v':
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break; /* ignore -v */
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default:
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usage(umount_usage);
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}
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}
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mtab_read();
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if (umountAll == TRUE) {
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exit(umount_all(useMtab));
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}
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if (do_umount(*argv, useMtab) == 0)
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exit(TRUE);
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perror("umount");
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return(FALSE);
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}
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