util-linux/umount.c - codeaurora/busybox - Gitiles

 /* vi: set sw=4 ts=4: */
 /*
  * Mini umount implementation for busybox
  *
  * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
  * Copyright (C) 2005 by Rob Landley <rob@landley.net>
  *
  * Licensed under GPLv2, see file LICENSE in this source tree.
  */

 //usage:#define umount_trivial_usage
 //usage:       "[OPTIONS] FILESYSTEM|DIRECTORY"
 //usage:#define umount_full_usage "\n\n"
 //usage:       "Unmount file systems\n"
 //usage:	IF_FEATURE_UMOUNT_ALL(
 //usage:     "\n	-a	Unmount all file systems" IF_FEATURE_MTAB_SUPPORT(" in /etc/mtab")
 //usage:	)
 //usage:	IF_FEATURE_MTAB_SUPPORT(
 //usage:     "\n	-n	Don't erase /etc/mtab entries"
 //usage:	)
 //usage:     "\n	-r	Try to remount devices as read-only if mount is busy"
 //usage:     "\n	-l	Lazy umount (detach filesystem)"
 //usage:     "\n	-f	Force umount (i.e., unreachable NFS server)"
 //usage:	IF_FEATURE_MOUNT_LOOP(
 //usage:     "\n	-D	Don't free loop device even if it has been used"
 //usage:	)
 //usage:
 //usage:#define umount_example_usage
 //usage:       "$ umount /dev/hdc1\n"

 #include <mntent.h>
 #include <sys/mount.h>
 #ifndef MNT_DETACH
 # define MNT_DETACH 0x00000002
 #endif
 #include "libbb.h"
 #include "common_bufsiz.h"

 #if defined(__dietlibc__)
 // TODO: This does not belong here.
 /* 16.12.2006, Sampo Kellomaki (sampo@iki.fi)
  * dietlibc-0.30 does not have implementation of getmntent_r() */
 static struct mntent *getmntent_r(FILE* stream, struct mntent* result,
 		char* buffer UNUSED_PARAM, int bufsize UNUSED_PARAM)
 {
 	struct mntent* ment = getmntent(stream);
 	return memcpy(result, ment, sizeof(*ment));
 }
 #endif

 /* Ignored: -v -t -i
  * bbox always acts as if -d is present.
  * -D can be used to suppress it (bbox extension).
  * Rationale:
  * (1) util-linux's umount does it if "loop=..." is seen in /etc/mtab:
  * thus, on many systems, bare umount _does_ drop loop devices.
  * (2) many users request this feature.
  */
 #define OPTION_STRING           "fldDnra" "vt:i"
 #define OPT_FORCE               (1 << 0) // Same as MNT_FORCE
 #define OPT_LAZY                (1 << 1) // Same as MNT_DETACH
 //#define OPT_FREE_LOOP           (1 << 2) // -d is assumed always present
 #define OPT_DONT_FREE_LOOP      (1 << 3)
 #define OPT_NO_MTAB             (1 << 4)
 #define OPT_REMOUNT             (1 << 5)
 #define OPT_ALL                 (ENABLE_FEATURE_UMOUNT_ALL ? (1 << 6) : 0)

 int umount_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int umount_main(int argc UNUSED_PARAM, char **argv)
 {
 	int doForce;
 	struct mntent me;
 	FILE *fp;
 	char *fstype = NULL;
 	int status = EXIT_SUCCESS;
 	unsigned opt;
 	struct mtab_list {
 		char *dir;
 		char *device;
 		struct mtab_list *next;
 	} *mtl, *m;

 	opt = getopt32(argv, OPTION_STRING, &fstype);
 	//argc -= optind;
 	argv += optind;

 	// MNT_FORCE and MNT_DETACH (from linux/fs.h) must match
 	// OPT_FORCE and OPT_LAZY.
 	BUILD_BUG_ON(OPT_FORCE != MNT_FORCE || OPT_LAZY != MNT_DETACH);
 	doForce = opt & (OPT_FORCE|OPT_LAZY);

 	/* 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 = NULL;

 	// 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).
 	fp = setmntent(bb_path_mtab_file, "r");
 	if (!fp) {
 		if (opt & OPT_ALL)
 			bb_error_msg_and_die("can't open '%s'", bb_path_mtab_file);
 	} else {
 		setup_common_bufsiz();
 		while (getmntent_r(fp, &me, bb_common_bufsiz1, COMMON_BUFSIZE)) {
 			/* Match fstype if passed */
 			if (!match_fstype(&me, fstype))
 				continue;
 			m = xzalloc(sizeof(*m));
 			m->next = mtl;
 			m->device = xstrdup(me.mnt_fsname);
 			m->dir = xstrdup(me.mnt_dir);
 			mtl = m;
 		}
 		endmntent(fp);
 	}

 	// If we're not umounting all, we need at least one argument.
 	if (!(opt & OPT_ALL) && !fstype) {
 		if (!argv[0])
 			bb_show_usage();
 		m = NULL;
 	}

 	// Loop through everything we're supposed to umount, and do so.
 	for (;;) {
 		int curstat;
 		char *zapit = *argv;
 		char *path;

 		// Do we already know what to umount this time through the loop?
 		if (m)
 			path = xstrdup(m->dir);
 		// For umount -a, end of mtab means time to exit.
 		else if (opt & OPT_ALL)
 			break;
 		// Use command line argument (and look it up in mtab list)
 		else {
 			if (!zapit)
 				break;
 			argv++;
 			path = xmalloc_realpath(zapit);
 			if (path) {
 				for (m = mtl; m; m = m->next)
 					if (strcmp(path, m->dir) == 0 || strcmp(path, m->device) == 0)
 						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;

 // umount from util-linux 2.22.2 does not do this:
 // umount -f uses umount2(MNT_FORCE) immediately,
 // not trying umount() first.
 // (Strangely, umount -fl ignores -f: it is equivalent to umount -l.
 // We do pass both flags in this case)
 #if 0
 		// Let's ask the thing nicely to unmount.
 		curstat = umount(zapit);

 		// Unmount with force and/or lazy flags, if necessary.
 		if (curstat && doForce)
 #endif
 			curstat = umount2(zapit, doForce);

 		// If still can't umount, maybe remount read-only?
 		if (curstat) {
 			if ((opt & OPT_REMOUNT) && errno == EBUSY && m) {
 				// Note! Even if we succeed here, later we should not
 				// free loop device or erase mtab entry!
 				const char *msg = "%s busy - remounted read-only";
 				curstat = mount(m->device, zapit, NULL, MS_REMOUNT|MS_RDONLY, NULL);
 				if (curstat) {
 					msg = "can't remount %s read-only";
 					status = EXIT_FAILURE;
 				}
 				bb_error_msg(msg, m->device);
 			} else {
 				status = EXIT_FAILURE;
 				bb_perror_msg("can't unmount %s", zapit);
 			}
 		} else {
 			// De-allocate the loop device.  This ioctl should be ignored on
 			// any non-loop block devices.
 			if (ENABLE_FEATURE_MOUNT_LOOP && !(opt & OPT_DONT_FREE_LOOP) && m)
 				del_loop(m->device);
 			if (ENABLE_FEATURE_MTAB_SUPPORT && !(opt & OPT_NO_MTAB) && m)
 				erase_mtab(m->dir);
 		}

 		// 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.
 		if (m) {
 			while ((m = m->next) != NULL)
 				// NB: if m is non-NULL, path is non-NULL as well
 				if ((opt & OPT_ALL) || strcmp(path, m->device) == 0)
 					break;
 		}
 		free(path);
 	}

 	// 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;
 		}
 	}

 	return status;
 }
	/* vi: set sw=4 ts=4: */
	/*
	* Mini umount implementation for busybox
	*
	* Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
	* Copyright (C) 2005 by Rob Landley <rob@landley.net>
	*
	* Licensed under GPLv2, see file LICENSE in this source tree.
	*/

	//usage:#define umount_trivial_usage
	//usage: "[OPTIONS] FILESYSTEM\|DIRECTORY"
	//usage:#define umount_full_usage "\n\n"
	//usage: "Unmount file systems\n"
	//usage: IF_FEATURE_UMOUNT_ALL(
	//usage: "\n -a Unmount all file systems" IF_FEATURE_MTAB_SUPPORT(" in /etc/mtab")
	//usage: )
	//usage: IF_FEATURE_MTAB_SUPPORT(
	//usage: "\n -n Don't erase /etc/mtab entries"
	//usage: )
	//usage: "\n -r Try to remount devices as read-only if mount is busy"
	//usage: "\n -l Lazy umount (detach filesystem)"
	//usage: "\n -f Force umount (i.e., unreachable NFS server)"
	//usage: IF_FEATURE_MOUNT_LOOP(
	//usage: "\n -D Don't free loop device even if it has been used"
	//usage: )
	//usage:
	//usage:#define umount_example_usage
	//usage: "$ umount /dev/hdc1\n"

	#include <mntent.h>
	#include <sys/mount.h>
	#ifndef MNT_DETACH
	# define MNT_DETACH 0x00000002
	#endif
	#include "libbb.h"
	#include "common_bufsiz.h"

	#if defined(__dietlibc__)
	// TODO: This does not belong here.
	/* 16.12.2006, Sampo Kellomaki (sampo@iki.fi)
	* dietlibc-0.30 does not have implementation of getmntent_r() */
	static struct mntent getmntent_r(FILE stream, struct mntent* result,
	char* buffer UNUSED_PARAM, int bufsize UNUSED_PARAM)
	{
	struct mntent* ment = getmntent(stream);
	return memcpy(result, ment, sizeof(*ment));
	}
	#endif

	/* Ignored: -v -t -i
	* bbox always acts as if -d is present.
	* -D can be used to suppress it (bbox extension).
	* Rationale:
	* (1) util-linux's umount does it if "loop=..." is seen in /etc/mtab:
	* thus, on many systems, bare umount _does_ drop loop devices.
	* (2) many users request this feature.
	*/
	#define OPTION_STRING "fldDnra" "vt:i"
	#define OPT_FORCE (1 << 0) // Same as MNT_FORCE
	#define OPT_LAZY (1 << 1) // Same as MNT_DETACH
	//#define OPT_FREE_LOOP (1 << 2) // -d is assumed always present
	#define OPT_DONT_FREE_LOOP (1 << 3)
	#define OPT_NO_MTAB (1 << 4)
	#define OPT_REMOUNT (1 << 5)
	#define OPT_ALL (ENABLE_FEATURE_UMOUNT_ALL ? (1 << 6) : 0)

	int umount_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
	int umount_main(int argc UNUSED_PARAM, char **argv)
	{
	int doForce;
	struct mntent me;
	FILE *fp;
	char *fstype = NULL;
	int status = EXIT_SUCCESS;
	unsigned opt;
	struct mtab_list {
	char *dir;
	char *device;
	struct mtab_list *next;
	} mtl, m;

	opt = getopt32(argv, OPTION_STRING, &fstype);
	//argc -= optind;
	argv += optind;

	// MNT_FORCE and MNT_DETACH (from linux/fs.h) must match
	// OPT_FORCE and OPT_LAZY.
	BUILD_BUG_ON(OPT_FORCE != MNT_FORCE \|\| OPT_LAZY != MNT_DETACH);
	doForce = opt & (OPT_FORCE\|OPT_LAZY);

	/* 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 = NULL;

	// 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).
	fp = setmntent(bb_path_mtab_file, "r");
	if (!fp) {
	if (opt & OPT_ALL)
	bb_error_msg_and_die("can't open '%s'", bb_path_mtab_file);
	} else {
	setup_common_bufsiz();
	while (getmntent_r(fp, &me, bb_common_bufsiz1, COMMON_BUFSIZE)) {
	/* Match fstype if passed */
	if (!match_fstype(&me, fstype))
	continue;
	m = xzalloc(sizeof(*m));
	m->next = mtl;
	m->device = xstrdup(me.mnt_fsname);
	m->dir = xstrdup(me.mnt_dir);
	mtl = m;
	}
	endmntent(fp);
	}

	// If we're not umounting all, we need at least one argument.
	if (!(opt & OPT_ALL) && !fstype) {
	if (!argv[0])
	bb_show_usage();
	m = NULL;
	}

	// Loop through everything we're supposed to umount, and do so.
	for (;;) {
	int curstat;
	char zapit = argv;
	char *path;

	// Do we already know what to umount this time through the loop?
	if (m)
	path = xstrdup(m->dir);
	// For umount -a, end of mtab means time to exit.
	else if (opt & OPT_ALL)
	break;
	// Use command line argument (and look it up in mtab list)
	else {
	if (!zapit)
	break;
	argv++;
	path = xmalloc_realpath(zapit);
	if (path) {
	for (m = mtl; m; m = m->next)
	if (strcmp(path, m->dir) == 0 \|\| strcmp(path, m->device) == 0)
	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;

	// umount from util-linux 2.22.2 does not do this:
	// umount -f uses umount2(MNT_FORCE) immediately,
	// not trying umount() first.
	// (Strangely, umount -fl ignores -f: it is equivalent to umount -l.
	// We do pass both flags in this case)
	#if 0
	// Let's ask the thing nicely to unmount.
	curstat = umount(zapit);

	// Unmount with force and/or lazy flags, if necessary.
	if (curstat && doForce)
	#endif
	curstat = umount2(zapit, doForce);

	// If still can't umount, maybe remount read-only?
	if (curstat) {
	if ((opt & OPT_REMOUNT) && errno == EBUSY && m) {
	// Note! Even if we succeed here, later we should not
	// free loop device or erase mtab entry!
	const char *msg = "%s busy - remounted read-only";
	curstat = mount(m->device, zapit, NULL, MS_REMOUNT\|MS_RDONLY, NULL);
	if (curstat) {
	msg = "can't remount %s read-only";
	status = EXIT_FAILURE;
	}
	bb_error_msg(msg, m->device);
	} else {
	status = EXIT_FAILURE;
	bb_perror_msg("can't unmount %s", zapit);
	}
	} else {
	// De-allocate the loop device. This ioctl should be ignored on
	// any non-loop block devices.
	if (ENABLE_FEATURE_MOUNT_LOOP && !(opt & OPT_DONT_FREE_LOOP) && m)
	del_loop(m->device);
	if (ENABLE_FEATURE_MTAB_SUPPORT && !(opt & OPT_NO_MTAB) && m)
	erase_mtab(m->dir);
	}

	// 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.
	if (m) {
	while ((m = m->next) != NULL)
	// NB: if m is non-NULL, path is non-NULL as well
	if ((opt & OPT_ALL) \|\| strcmp(path, m->device) == 0)
	break;
	}
	free(path);
	}

	// 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;
	}
	}

	return status;
	}