154 lines
4.1 KiB
C
154 lines
4.1 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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* Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
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* Copyright (C) 2005 by Rob Landley <rob@landley.net>
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*
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* This program is licensed under the GNU General Public license (GPL)
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* version 2 or later, see http://www.fsf.org/licensing/licenses/gpl.html
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* or the file "LICENSE" in the busybox source tarball for the full text.
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*
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*/
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#include <limits.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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#include <string.h>
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#include <stdlib.h>
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#include <sys/mount.h>
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#include <getopt.h>
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#include "busybox.h"
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#define OPTION_STRING "flDnrvad"
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#define OPT_FORCE 1
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#define OPT_LAZY 2
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#define OPT_DONTFREELOOP 4
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#define OPT_NO_MTAB 8
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#define OPT_REMOUNT 16
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#define OPT_IGNORED 32 // -v is ignored
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#define OPT_ALL (ENABLE_FEATURE_UMOUNT_ALL ? 64 : 0)
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int umount_main(int argc, char **argv)
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{
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int doForce;
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char path[2*PATH_MAX];
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struct mntent me;
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FILE *fp;
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int status = EXIT_SUCCESS;
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unsigned long opt;
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struct mtab_list {
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char *dir;
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char *device;
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struct mtab_list *next;
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} *mtl, *m;
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/* Parse any options */
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opt = bb_getopt_ulflags(argc, argv, OPTION_STRING);
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argc -= optind;
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argv += optind;
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doForce = MAX((opt & OPT_FORCE), (opt & OPT_LAZY));
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/* Get a list of mount points from mtab. We read them all in now mostly
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* for umount -a (so we don't have to worry about the list changing while
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* we iterate over it, or about getting stuck in a loop on the same failing
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* entry. Notice that this also naturally reverses the list so that -a
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* umounts the most recent entries first. */
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m = mtl = 0;
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/* If we're umounting all, then m points to the start of the list and
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* the argument list should be empty (which will match all). */
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if (!(fp = setmntent(bb_path_mtab_file, "r"))) {
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if (opt & OPT_ALL)
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bb_error_msg_and_die("Cannot open %s", bb_path_mtab_file);
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} else while (getmntent_r(fp,&me,path,sizeof(path))) {
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m = xmalloc(sizeof(struct mtab_list));
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m->next = mtl;
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m->device = bb_xstrdup(me.mnt_fsname);
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m->dir = bb_xstrdup(me.mnt_dir);
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mtl = m;
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}
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endmntent(fp);
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/* If we're not mounting all, we need at least one argument. */
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if (!(opt & OPT_ALL)) {
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m = 0;
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if (!argc) bb_show_usage();
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}
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// Loop through everything we're supposed to umount, and do so.
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for (;;) {
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int curstat;
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// Do we already know what to umount this time through the loop?
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if (m) safe_strncpy(path, m->dir, PATH_MAX);
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// For umount -a, end of mtab means time to exit.
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else if (opt & OPT_ALL) break;
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// Get next command line argument (and look it up in mtab list)
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else if (!argc--) break;
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else {
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realpath(*argv++, path);
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for (m = mtl; m; m = m->next)
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if (!strcmp(path, m->dir) || !strcmp(path, m->device))
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break;
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}
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// Let's ask the thing nicely to unmount.
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curstat = umount(path);
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// Force the unmount, if necessary.
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if (curstat && doForce) {
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curstat = umount2(path, doForce);
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if (curstat)
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bb_error_msg_and_die("forced umount of %s failed!", path);
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}
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// If still can't umount, maybe remount read-only?
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if (curstat && (opt & OPT_REMOUNT) && errno == EBUSY && m) {
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curstat = mount(m->device, path, NULL, MS_REMOUNT|MS_RDONLY, NULL);
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bb_error_msg(curstat ? "Cannot remount %s read-only" :
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"%s busy - remounted read-only", m->device);
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}
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/* De-allocate the loop device. This ioctl should be ignored on any
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* non-loop block devices. */
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if (ENABLE_FEATURE_MOUNT_LOOP && !(opt & OPT_DONTFREELOOP) && m)
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del_loop(m->device);
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if (curstat) {
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/* Yes, the ENABLE is redundant here, but the optimizer for ARM
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* can't do simple constant propagation in local variables... */
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if(ENABLE_FEATURE_MTAB_SUPPORT && !(opt & OPT_NO_MTAB) && m)
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erase_mtab(m->dir);
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status = EXIT_FAILURE;
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bb_perror_msg("Couldn't umount %s", path);
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}
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// Find next matching mtab entry for -a or umount /dev
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while (m && (m = m->next))
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if ((opt & OPT_ALL) || !strcmp(path,m->device))
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break;
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}
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// Free mtab list if necessary
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if (ENABLE_FEATURE_CLEAN_UP) {
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while (mtl) {
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m = mtl->next;
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free(mtl->device);
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free(mtl->dir);
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free(mtl);
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mtl=m;
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}
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}
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return status;
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}
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