Ejemplo n.º 1
0
static int prepare_helper_from_options(struct libmnt_context *cxt,
				       const char *name)
{
	char *suffix = NULL;
	const char *opts;
	size_t valsz;

	if (mnt_context_is_nohelpers(cxt))
		return 0;

	opts = mnt_fs_get_user_options(cxt->fs);
	if (!opts)
		return 0;

	if (mnt_optstr_get_option(opts, name, &suffix, &valsz))
		return 0;

	suffix = strndup(suffix, valsz);
	if (!suffix)
		return -ENOMEM;

	DBG(CXT, mnt_debug_h(cxt, "umount: umount.%s %s requested", suffix, name));

	return mnt_context_prepare_helper(cxt, "umount", suffix);
}
Ejemplo n.º 2
0
/* check if @devname is loopdev and if the device is associated
 * with a source from @fstab_fs
 */
static int is_associated_fs(const char *devname, struct libmnt_fs *fs)
{
	uintmax_t offset = 0;
	const char *src;
	char *val, *optstr;
	size_t valsz;
	int flags = 0;

	/* check if it begins with /dev/loop */
	if (strncmp(devname, _PATH_DEV_LOOP, sizeof(_PATH_DEV_LOOP) - 1))
		return 0;

	src = mnt_fs_get_srcpath(fs);
	if (!src)
		return 0;

	/* check for offset option in @fs */
	optstr = (char *) mnt_fs_get_user_options(fs);

	if (optstr &&
	    mnt_optstr_get_option(optstr, "offset", &val, &valsz) == 0) {
		flags |= LOOPDEV_FL_OFFSET;

		if (mnt_parse_offset(val, valsz, &offset) != 0)
			return 0;
	}

	return loopdev_is_used(devname, src, offset, flags);
}
Ejemplo n.º 3
0
static int fprintf_utab_fs(FILE *f, struct libmnt_fs *fs)
{
	char *p;
	int rc = 0;

	assert(fs);
	assert(f);

	if (!fs || !f)
		return -EINVAL;

	p = mangle(mnt_fs_get_source(fs));
	if (p) {
		rc = fprintf(f, "SRC=%s ", p);
		free(p);
	}
	if (rc >= 0) {
		p = mangle(mnt_fs_get_target(fs));
		if (p) {
			rc = fprintf(f, "TARGET=%s ", p);
			free(p);
		}
	}
	if (rc >= 0) {
		p = mangle(mnt_fs_get_root(fs));
		if (p) {
			rc = fprintf(f, "ROOT=%s ", p);
			free(p);
		}
	}
	if (rc >= 0) {
		p = mangle(mnt_fs_get_bindsrc(fs));
		if (p) {
			rc = fprintf(f, "BINDSRC=%s ", p);
			free(p);
		}
	}
	if (rc >= 0) {
		p = mangle(mnt_fs_get_attributes(fs));
		if (p) {
			rc = fprintf(f, "ATTRS=%s ", p);
			free(p);
		}
	}
	if (rc >= 0) {
		p = mangle(mnt_fs_get_user_options(fs));
		if (p) {
			rc = fprintf(f, "OPTS=%s", p);
			free(p);
		}
	}
	if (rc >= 0)
		rc = fprintf(f, "\n");

	if (rc > 0)
		rc = 0;	/* success */
	return rc;
}
Ejemplo n.º 4
0
/* Check, if there already exists a mounted loop device on the mountpoint node
 * with the same parameters.
 */
static int is_mounted_same_loopfile(struct libmnt_context *cxt,
				    const char *target,
				    const char *backing_file,
				    uint64_t offset)
{
	struct libmnt_table *tb;
	struct libmnt_iter itr;
	struct libmnt_fs *fs;
	struct libmnt_cache *cache;

	assert(cxt);
	assert(cxt->fs);
	assert((cxt->flags & MNT_FL_MOUNTFLAGS_MERGED));

	if (!target || !backing_file || mnt_context_get_mtab(cxt, &tb))
		return 0;

	DBG(CXT, mnt_debug_h(cxt, "checking if %s mounted on %s",
				backing_file, target));

	cache = mnt_context_get_cache(cxt);
	mnt_reset_iter(&itr, MNT_ITER_BACKWARD);

	/* Search for mountpoint node in mtab, procceed if any of these has the
	 * loop option set or the device is a loop device
	 */
	while (mnt_table_next_fs(tb, &itr, &fs) == 0) {
		const char *src = mnt_fs_get_source(fs);
		const char *opts = mnt_fs_get_user_options(fs);
		char *val;
		size_t len;
		int res = 0;

		if (!src || !mnt_fs_match_target(fs, target, cache))
			continue;

		if (strncmp(src, "/dev/loop", 9) == 0) {
			res = loopdev_is_used((char *) src, backing_file,
					offset, LOOPDEV_FL_OFFSET);

		} else if (opts && (cxt->user_mountflags & MNT_MS_LOOP) &&
		    mnt_optstr_get_option(opts, "loop", &val, &len) == 0 && val) {

			val = strndup(val, len);
			res = loopdev_is_used((char *) val, backing_file,
					offset, LOOPDEV_FL_OFFSET);
			free(val);
		}

		if (res) {
			DBG(CXT, mnt_debug_h(cxt, "%s already mounted", backing_file));
			return 1;
		}
	}

	return 0;
}
Ejemplo n.º 5
0
/*
 * Store mount options to mtab (or /dev/.mount/utab), called from mount.nfs.
 *
 * Note that on systems without /etc/mtab the fs-specific options are not
 * managed by libmount at all. We have to use "mount attributes" that are
 * private for mount.<type> helpers.
 */
static void store_mount_options(struct libmnt_fs *fs, const char *nfs_opts)
{
    char *o = NULL;

    mnt_fs_set_attributes(fs, nfs_opts);	/* for non-mtab systems */

    /* for mtab create a new options list */
    mnt_optstr_append_option(&o, mnt_fs_get_vfs_options(fs), NULL);
    mnt_optstr_append_option(&o, nfs_opts, NULL);
    mnt_optstr_append_option(&o, mnt_fs_get_user_options(fs), NULL);

    mnt_fs_set_options(fs, o);
    free(o);
}
Ejemplo n.º 6
0
/*
 * This function uses @uf to found corresponding record in @tb, then the record
 * from @tb is updated (user specific mount options are added).
 *
 * Note that @uf must contain only user specific mount options instead of
 * VFS options (note that FS options are ignored).
 *
 * Returns modified filesystem (from @tb) or NULL.
 */
static struct libmnt_fs *mnt_table_merge_user_fs(struct libmnt_table *tb, struct libmnt_fs *uf)
{
	struct libmnt_fs *fs;
	struct libmnt_iter itr;
	const char *optstr, *src, *target, *root, *attrs;

	assert(tb);
	assert(uf);
	if (!tb || !uf)
		return NULL;

	DBG(TAB, mnt_debug_h(tb, "merging user fs"));

	src = mnt_fs_get_srcpath(uf);
	target = mnt_fs_get_target(uf);
	optstr = mnt_fs_get_user_options(uf);
	attrs = mnt_fs_get_attributes(uf);
	root = mnt_fs_get_root(uf);

	if (!src || !target || !root || (!attrs && !optstr))
		return NULL;

	mnt_reset_iter(&itr, MNT_ITER_BACKWARD);

	while(mnt_table_next_fs(tb, &itr, &fs) == 0) {
		const char *s = mnt_fs_get_srcpath(fs),
			   *t = mnt_fs_get_target(fs),
			   *r = mnt_fs_get_root(fs);

		if (fs->flags & MNT_FS_MERGED)
			continue;

		if (s && t && r && !strcmp(t, target) &&
		    !strcmp(s, src) && !strcmp(r, root))
			break;
	}

	if (fs) {
		DBG(TAB, mnt_debug_h(tb, "found fs -- appending user optstr"));
		mnt_fs_append_options(fs, optstr);
		mnt_fs_append_attributes(fs, attrs);
		mnt_fs_set_bindsrc(fs, mnt_fs_get_bindsrc(uf));
		fs->flags |= MNT_FS_MERGED;

		DBG(TAB, mnt_debug_h(tb, "found fs:"));
		DBG(TAB, mnt_fs_print_debug(fs, stderr));
	}
	return fs;
}
Ejemplo n.º 7
0
/*
 * Note that cxt->fs contains relevant mtab entry!
 */
static int evaluate_permissions(struct libmnt_context *cxt)
{
	struct libmnt_table *fstab;
	unsigned long u_flags = 0;
	const char *tgt, *src, *optstr;
	int rc, ok = 0;
	struct libmnt_fs *fs;

	assert(cxt);
	assert(cxt->fs);
	assert((cxt->flags & MNT_FL_MOUNTFLAGS_MERGED));

	if (!cxt || !cxt->fs)
		return -EINVAL;

	if (!mnt_context_is_restricted(cxt))
		 return 0;		/* superuser mount */

	DBG(CXT, mnt_debug_h(cxt, "umount: evaluating permissions"));

	if (!(cxt->flags & MNT_FL_TAB_APPLIED)) {
		DBG(CXT, mnt_debug_h(cxt,
				"cannot find %s in mtab and you are not root",
				mnt_fs_get_target(cxt->fs)));
		goto eperm;
	}

	if (cxt->user_mountflags & MNT_MS_UHELPER) {
		/* on uhelper= mount option based helper */
		rc = prepare_helper_from_options(cxt, "uhelper");
		if (rc)
			return rc;
		if (cxt->helper)
			return 0;	/* we'll call /sbin/umount.<uhelper> */
	}

	/*
	 * User mounts has to be in /etc/fstab
	 */
	rc = mnt_context_get_fstab(cxt, &fstab);
	if (rc)
		return rc;

	tgt = mnt_fs_get_target(cxt->fs);
	src = mnt_fs_get_source(cxt->fs);

	if (mnt_fs_get_bindsrc(cxt->fs)) {
		src = mnt_fs_get_bindsrc(cxt->fs);
		DBG(CXT, mnt_debug_h(cxt,
				"umount: using bind source: %s", src));
	}

	/* If fstab contains the two lines
	 *	/dev/sda1 /mnt/zip auto user,noauto  0 0
	 *	/dev/sda4 /mnt/zip auto user,noauto  0 0
	 * then "mount /dev/sda4" followed by "umount /mnt/zip" used to fail.
	 * So, we must not look for file, but for the pair (dev,file) in fstab.
	  */
	fs = mnt_table_find_pair(fstab, src, tgt, MNT_ITER_FORWARD);
	if (!fs) {
		/*
		 * It's possible that there is /path/file.img in fstab and
		 * /dev/loop0 in mtab -- then we have to check releation
		 * between loopdev and the file.
		 */
		fs = mnt_table_find_target(fstab, tgt, MNT_ITER_FORWARD);
		if (fs) {
			const char *dev = mnt_fs_get_srcpath(cxt->fs);		/* devname from mtab */

			if (!dev || !is_associated_fs(dev, fs))
				fs = NULL;
		}
		if (!fs) {
			DBG(CXT, mnt_debug_h(cxt,
					"umount %s: mtab disagrees with fstab",
					tgt));
			goto eperm;
		}
	}

	/*
	 * User mounting and unmounting is allowed only if fstab contains one
	 * of the options `user', `users' or `owner' or `group'.
	 *
	 * The option `users' allows arbitrary users to mount and unmount -
	 * this may be a security risk.
	 *
	 * The options `user', `owner' and `group' only allow unmounting by the
	 * user that mounted (visible in mtab).
	 */
	optstr = mnt_fs_get_user_options(fs);	/* FSTAB mount options! */
	if (!optstr)
		goto eperm;

	if (mnt_optstr_get_flags(optstr, &u_flags,
				mnt_get_builtin_optmap(MNT_USERSPACE_MAP)))
		goto eperm;

	if (u_flags & MNT_MS_USERS) {
		DBG(CXT, mnt_debug_h(cxt,
			"umount: promiscuous setting ('users') in fstab"));
		return 0;
	}
	/*
	 * Check user=<username> setting from mtab if there is user, owner or
	 * group option in /etc/fstab
	 */
	if (u_flags & (MNT_MS_USER | MNT_MS_OWNER | MNT_MS_GROUP)) {

		char *curr_user = NULL;
		char *mtab_user = NULL;
		size_t sz;

		DBG(CXT, mnt_debug_h(cxt,
				"umount: checking user=<username> from mtab"));

		curr_user = mnt_get_username(getuid());

		if (!curr_user) {
			DBG(CXT, mnt_debug_h(cxt, "umount %s: cannot "
				"convert %d to username", tgt, getuid()));
			goto eperm;
		}

		/* get options from mtab */
		optstr = mnt_fs_get_user_options(cxt->fs);
		if (optstr && !mnt_optstr_get_option(optstr,
					"user", &mtab_user, &sz) && sz)
			ok = !strncmp(curr_user, mtab_user, sz);
	}

	if (ok) {
		DBG(CXT, mnt_debug_h(cxt, "umount %s is allowed", tgt));
		return 0;
	}
eperm:
	DBG(CXT, mnt_debug_h(cxt, "umount is not allowed for you"));
	return -EPERM;
}
Ejemplo n.º 8
0
/**
 * mnt_context_next_mount:
 * @cxt: context
 * @itr: iterator
 * @fs: returns the current filesystem
 * @mntrc: returns the return code from mnt_context_mount()
 * @ignored: returns 1 for not matching and 2 for already mounted filesystems
 *
 * This function tries to mount the next filesystem from fstab (as returned by
 * mnt_context_get_fstab()). See also mnt_context_set_fstab().
 *
 * You can filter out filesystems by:
 *	mnt_context_set_options_pattern() to simulate mount -a -O pattern
 *	mnt_context_set_fstype_pattern()  to simulate mount -a -t pattern
 *
 * If the filesystem is already mounted or does not match defined criteria,
 * then the mnt_context_next_mount() function returns zero, but the @ignored is
 * non-zero. Note that the root filesystem and filesystems with "noauto" option
 * are always ignored.
 *
 * If mount(2) syscall or mount.type helper failed, then the
 * mnt_context_next_mount() function returns zero, but the @mntrc is non-zero.
 * Use also mnt_context_get_status() to check if the filesystem was
 * successfully mounted.
 *
 * Returns: 0 on success,
 *         <0 in case of error (!= mount(2) errors)
 *          1 at the end of the list.
 */
int mnt_context_next_mount(struct libmnt_context *cxt,
			   struct libmnt_iter *itr,
			   struct libmnt_fs **fs,
			   int *mntrc,
			   int *ignored)
{
	struct libmnt_table *fstab, *mtab;
	const char *o, *tgt;
	int rc, mounted = 0;

	if (ignored)
		*ignored = 0;
	if (mntrc)
		*mntrc = 0;

	if (!cxt || !fs || !itr)
		return -EINVAL;

	mtab = cxt->mtab;
	cxt->mtab = NULL;		/* do not reset mtab */
	mnt_reset_context(cxt);
	cxt->mtab = mtab;

	rc = mnt_context_get_fstab(cxt, &fstab);
	if (rc)
		return rc;

	rc = mnt_table_next_fs(fstab, itr, fs);
	if (rc != 0)
		return rc;	/* more filesystems (or error) */

	o = mnt_fs_get_user_options(*fs);
	tgt = mnt_fs_get_target(*fs);

	DBG(CXT, mnt_debug_h(cxt, "next-mount: trying %s", tgt));

	/*  ignore swap */
	if (mnt_fs_is_swaparea(*fs) ||

	/* ignore root filesystem */
	   (tgt && (strcmp(tgt, "/") == 0 || strcmp(tgt, "root") == 0)) ||

	/* ignore noauto filesystems */
	   (o && mnt_optstr_get_option(o, "noauto", NULL, NULL) == 0) ||

	/* ignore filesystems not match with options patterns */
	   (cxt->fstype_pattern && !mnt_fs_match_fstype(*fs,
					cxt->fstype_pattern)) ||

	/* ignore filesystems not match with type patterns */
	   (cxt->optstr_pattern && !mnt_fs_match_options(*fs,
					cxt->optstr_pattern))) {
		if (ignored)
			*ignored = 1;
		DBG(CXT, mnt_debug_h(cxt, "next-mount: not-match "
				"[fstype: %s, t-pattern: %s, options: %s, O-pattern: %s]",
				mnt_fs_get_fstype(*fs),
				cxt->fstype_pattern,
				mnt_fs_get_options(*fs),
				cxt->optstr_pattern));
		return 0;
	}

	/* ignore already mounted filesystems */
	rc = mnt_context_is_fs_mounted(cxt, *fs, &mounted);
	if (rc)
		return rc;
	if (mounted) {
		if (ignored)
			*ignored = 2;
		return 0;
	}

	if (mnt_context_is_fork(cxt)) {
		rc = mnt_fork_context(cxt);
		if (rc)
			return rc;		/* fork error */

		if (mnt_context_is_parent(cxt)) {
			return 0;		/* parent */
		}
	}

	/* child or non-forked */

	rc = mnt_context_set_fs(cxt, *fs);
	if (!rc) {
		rc = mnt_context_mount(cxt);
		if (mntrc)
			*mntrc = rc;
	}

	if (mnt_context_is_child(cxt)) {
		DBG(CXT, mnt_debug_h(cxt, "next-mount: child exit [rc=%d]", rc));
		DBG_FLUSH;
		exit(rc);
	}
	return 0;
}
Ejemplo n.º 9
0
int mnt_context_setup_loopdev(struct libmnt_context *cxt)
{
	const char *backing_file, *optstr, *loopdev = NULL;
	char *val = NULL, *loopval = NULL;
	size_t len;
	struct loopdev_cxt lc;
	int rc = 0, lo_flags = 0;
	uint64_t offset = 0, sizelimit = 0;

	assert(cxt);
	assert(cxt->fs);
	assert((cxt->flags & MNT_FL_MOUNTFLAGS_MERGED));

	backing_file = mnt_fs_get_srcpath(cxt->fs);
	if (!backing_file)
		return -EINVAL;

	DBG(LOOP, ul_debugobj(cxt, "trying to setup device for %s", backing_file));

	if (cxt->mountflags & MS_RDONLY) {
		DBG(LOOP, ul_debugobj(cxt, "enabling READ-ONLY flag"));
		lo_flags |= LO_FLAGS_READ_ONLY;
	}

	optstr = mnt_fs_get_user_options(cxt->fs);

	/*
	 * loop=
	 */
	if (rc == 0 && (cxt->user_mountflags & MNT_MS_LOOP) &&
	    mnt_optstr_get_option(optstr, "loop", &val, &len) == 0 && val) {
		loopval = strndup(val, len);
		rc = loopval ? 0 : -ENOMEM;
	}

	/*
	 * offset=
	 */
	if (rc == 0 && (cxt->user_mountflags & MNT_MS_OFFSET) &&
	    mnt_optstr_get_option(optstr, "offset", &val, &len) == 0) {
		rc = mnt_parse_offset(val, len, &offset);
		if (rc) {
			DBG(LOOP, ul_debugobj(cxt, "failed to parse offset="));
			rc = -MNT_ERR_MOUNTOPT;
		}
	}

	/*
	 * sizelimit=
	 */
	if (rc == 0 && (cxt->user_mountflags & MNT_MS_SIZELIMIT) &&
	    mnt_optstr_get_option(optstr, "sizelimit", &val, &len) == 0) {
		rc = mnt_parse_offset(val, len, &sizelimit);
		if (rc) {
			DBG(LOOP, ul_debugobj(cxt, "failed to parse sizelimit="));
			rc = -MNT_ERR_MOUNTOPT;
		}
	}

	/*
	 * encryption=
	 */
	if (rc == 0 && (cxt->user_mountflags & MNT_MS_ENCRYPTION) &&
	    mnt_optstr_get_option(optstr, "encryption", &val, &len) == 0) {
		DBG(LOOP, ul_debugobj(cxt, "encryption no longer supported"));
		rc = -MNT_ERR_MOUNTOPT;
	}

	if (rc == 0 && is_mounted_same_loopfile(cxt,
				mnt_context_get_target(cxt),
				backing_file, offset))
		rc = -EBUSY;

	if (rc)
		goto done_no_deinit;

	/* It is possible to mount the same file more times. If we set more
	 * than one loop device referring to the same file, kernel has no
	 * mechanism to detect it. To prevent data corruption, the same loop
	 * device has to be recycled.
	*/
	if (backing_file) {
		rc = loopcxt_init(&lc, 0);
		if (rc)
			goto done_no_deinit;

		rc = loopcxt_find_overlap(&lc, backing_file, offset, sizelimit);
		switch (rc) {
		case 0: /* not found */
			DBG(LOOP, ul_debugobj(cxt, "not found overlaping loopdev"));
			loopcxt_deinit(&lc);
			break;

		case 1:	/* overlap */
			DBG(LOOP, ul_debugobj(cxt, "overlaping %s detected",
						loopcxt_get_device(&lc)));
			rc = -MNT_ERR_LOOPOVERLAP;
			goto done;

		case 2: /* overlap -- full size and offset match (reuse) */
		{
			uint32_t lc_encrypt_type;

			DBG(LOOP, ul_debugobj(cxt, "re-using existing loop device %s",
				loopcxt_get_device(&lc)));

			/* Once a loop is initialized RO, there is no
			 * way to change its parameters. */
			if (loopcxt_is_readonly(&lc)
			    && !(lo_flags & LO_FLAGS_READ_ONLY)) {
				DBG(LOOP, ul_debugobj(cxt, "%s is read-only",
						loopcxt_get_device(&lc)));
				rc = -EROFS;
				goto done;
			}

			/* This is no more supported, but check to be safe. */
			if (loopcxt_get_encrypt_type(&lc, &lc_encrypt_type) == 0
			    && lc_encrypt_type != LO_CRYPT_NONE) {
				DBG(LOOP, ul_debugobj(cxt, "encryption no longer supported for device %s",
					loopcxt_get_device(&lc)));
				rc = -MNT_ERR_LOOPOVERLAP;
				goto done;
			}
			rc = 0;
			goto success;
		}
		default: /* error */
			goto done;
		}
	}

	DBG(LOOP, ul_debugobj(cxt, "not found; create a new loop device"));
	rc = loopcxt_init(&lc, 0);
	if (rc)
		goto done_no_deinit;
	if (loopval) {
		rc = loopcxt_set_device(&lc, loopval);
		if (rc == 0)
			loopdev = loopcxt_get_device(&lc);
	}
	if (rc)
		goto done;

	/* since 2.6.37 we don't have to store backing filename to mtab
	 * because kernel provides the name in /sys.
	 */
	if (get_linux_version() >= KERNEL_VERSION(2, 6, 37) ||
	    !mnt_context_mtab_writable(cxt)) {
		DBG(LOOP, ul_debugobj(cxt, "enabling AUTOCLEAR flag"));
		lo_flags |= LO_FLAGS_AUTOCLEAR;
	}

	do {
		/* found free device */
		if (!loopdev) {
			rc = loopcxt_find_unused(&lc);
			if (rc)
				goto done;
			DBG(LOOP, ul_debugobj(cxt, "trying to use %s",
						loopcxt_get_device(&lc)));
		}

		/* set device attributes
		 * -- note that loopcxt_find_unused() resets "lc"
		 */
		rc = loopcxt_set_backing_file(&lc, backing_file);

		if (!rc && offset)
			rc = loopcxt_set_offset(&lc, offset);
		if (!rc && sizelimit)
			rc = loopcxt_set_sizelimit(&lc, sizelimit);
		if (!rc)
			loopcxt_set_flags(&lc, lo_flags);
		if (rc) {
			DBG(LOOP, ul_debugobj(cxt, "failed to set loop attributes"));
			goto done;
		}

		/* setup the device */
		rc = loopcxt_setup_device(&lc);
		if (!rc)
			break;		/* success */

		if (loopdev || rc != -EBUSY) {
			DBG(LOOP, ul_debugobj(cxt, "failed to setup device"));
			rc = -MNT_ERR_LOOPDEV;
			goto done;
		}
		DBG(LOOP, ul_debugobj(cxt, "device stolen...trying again"));
	} while (1);

success:
	if (!rc)
		rc = mnt_fs_set_source(cxt->fs, loopcxt_get_device(&lc));

	if (!rc) {
		/* success */
		cxt->flags |= MNT_FL_LOOPDEV_READY;

		if ((cxt->user_mountflags & MNT_MS_LOOP) &&
		    loopcxt_is_autoclear(&lc)) {
			/*
			 * autoclear flag accepted by the kernel, don't store
			 * the "loop=" option to mtab.
			 */
			DBG(LOOP, ul_debugobj(cxt, "removing unnecessary loop= from mtab"));
			cxt->user_mountflags &= ~MNT_MS_LOOP;
			mnt_optstr_remove_option(&cxt->fs->user_optstr, "loop");
		}

		if (!(cxt->mountflags & MS_RDONLY) &&
		    loopcxt_is_readonly(&lc))
			/*
			 * mount planned read-write, but loopdev is read-only,
			 * let's fix mount options...
			 */
			mnt_context_set_mflags(cxt, cxt->mountflags | MS_RDONLY);

		/* we have to keep the device open until mount(1),
		 * otherwise it will be auto-cleared by kernel
		 */
		cxt->loopdev_fd = loopcxt_get_fd(&lc);
		if (cxt->loopdev_fd < 0) {
			DBG(LOOP, ul_debugobj(cxt, "failed to get loopdev FD"));
			rc = -errno;
		} else
			loopcxt_set_fd(&lc, -1, 0);
	}
done:
	loopcxt_deinit(&lc);
done_no_deinit:
	free(loopval);
	return rc;
}
Ejemplo n.º 10
0
int mnt_context_setup_loopdev(struct libmnt_context *cxt)
{
	const char *backing_file, *optstr, *loopdev = NULL;
	char *val = NULL;
	size_t len;
	struct loopdev_cxt lc;
	int rc = 0, lo_flags = 0;
	uint64_t offset = 0, sizelimit = 0;

	assert(cxt->fs);
	assert((cxt->flags & MNT_FL_MOUNTFLAGS_MERGED));

	if (!cxt)
		return -EINVAL;

	backing_file = mnt_fs_get_srcpath(cxt->fs);
	if (!backing_file)
		return -EINVAL;

	DBG(CXT, ul_debugobj(cxt, "trying to setup loopdev for %s", backing_file));

	if (cxt->mountflags & MS_RDONLY) {
		DBG(CXT, ul_debugobj(cxt, "enabling READ-ONLY flag"));
		lo_flags |= LO_FLAGS_READ_ONLY;
	}

	rc = loopcxt_init(&lc, 0);
	if (rc)
		return rc;

	ON_DBG(CXT, loopcxt_enable_debug(&lc, 1));

	optstr = mnt_fs_get_user_options(cxt->fs);

	/*
	 * loop=
	 */
	if (rc == 0 && (cxt->user_mountflags & MNT_MS_LOOP) &&
	    mnt_optstr_get_option(optstr, "loop", &val, &len) == 0 && val) {

		val = strndup(val, len);
		rc = val ? loopcxt_set_device(&lc, val) : -ENOMEM;
		free(val);

		if (rc == 0)
			loopdev = loopcxt_get_device(&lc);
	}

	/*
	 * offset=
	 */
	if (rc == 0 && (cxt->user_mountflags & MNT_MS_OFFSET) &&
	    mnt_optstr_get_option(optstr, "offset", &val, &len) == 0) {
		rc = mnt_parse_offset(val, len, &offset);
		if (rc) {
			DBG(CXT, ul_debugobj(cxt, "failed to parse offset="));
			rc = -MNT_ERR_MOUNTOPT;
		}
	}

	/*
	 * sizelimit=
	 */
	if (rc == 0 && (cxt->user_mountflags & MNT_MS_SIZELIMIT) &&
	    mnt_optstr_get_option(optstr, "sizelimit", &val, &len) == 0) {
		rc = mnt_parse_offset(val, len, &sizelimit);
		if (rc) {
			DBG(CXT, ul_debugobj(cxt, "failed to parse sizelimit="));
			rc = -MNT_ERR_MOUNTOPT;
		}
	}

	/*
	 * encryption=
	 */
	if (rc == 0 && (cxt->user_mountflags & MNT_MS_ENCRYPTION) &&
	    mnt_optstr_get_option(optstr, "encryption", &val, &len) == 0) {
		DBG(CXT, ul_debugobj(cxt, "encryption no longer supported"));
		rc = -MNT_ERR_MOUNTOPT;
	}

	if (rc == 0 && is_mounted_same_loopfile(cxt,
				mnt_context_get_target(cxt),
				backing_file, offset))
		rc = -EBUSY;

	if (rc)
		goto done;

	/* since 2.6.37 we don't have to store backing filename to mtab
	 * because kernel provides the name in /sys.
	 */
	if (get_linux_version() >= KERNEL_VERSION(2, 6, 37) ||
	    !mnt_context_mtab_writable(cxt)) {
		DBG(CXT, ul_debugobj(cxt, "enabling AUTOCLEAR flag"));
		lo_flags |= LO_FLAGS_AUTOCLEAR;
	}

	do {
		/* found free device */
		if (!loopdev) {
			rc = loopcxt_find_unused(&lc);
			if (rc)
				goto done;
			DBG(CXT, ul_debugobj(cxt, "trying to use %s",
						loopcxt_get_device(&lc)));
		}

		/* set device attributes
		 * -- note that loopcxt_find_unused() resets "lc"
		 */
		rc = loopcxt_set_backing_file(&lc, backing_file);

		if (!rc && offset)
			rc = loopcxt_set_offset(&lc, offset);
		if (!rc && sizelimit)
			rc = loopcxt_set_sizelimit(&lc, sizelimit);
		if (!rc)
			loopcxt_set_flags(&lc, lo_flags);
		if (rc) {
			DBG(CXT, ul_debugobj(cxt, "failed to set loopdev attributes"));
			goto done;
		}

		/* setup the device */
		rc = loopcxt_setup_device(&lc);
		if (!rc)
			break;		/* success */

		if (loopdev || rc != -EBUSY) {
			DBG(CXT, ul_debugobj(cxt, "failed to setup device"));
			rc = -MNT_ERR_LOOPDEV;
			goto done;
		}
		DBG(CXT, ul_debugobj(cxt, "loopdev stolen...trying again"));
	} while (1);

	if (!rc)
		rc = mnt_fs_set_source(cxt->fs, loopcxt_get_device(&lc));

	if (!rc) {
		/* success */
		cxt->flags |= MNT_FL_LOOPDEV_READY;

		if ((cxt->user_mountflags & MNT_MS_LOOP) &&
		    loopcxt_is_autoclear(&lc)) {
			/*
			 * autoclear flag accepted by the kernel, don't store
			 * the "loop=" option to mtab.
			 */
			cxt->user_mountflags &= ~MNT_MS_LOOP;
			mnt_optstr_remove_option(&cxt->fs->user_optstr, "loop");
		}

		if (!(cxt->mountflags & MS_RDONLY) &&
		    loopcxt_is_readonly(&lc))
			/*
			 * mount planned read-write, but loopdev is read-only,
			 * let's fix mount options...
			 */
			mnt_context_set_mflags(cxt, cxt->mountflags | MS_RDONLY);

		/* we have to keep the device open until mount(1),
		 * otherwise it will be auto-cleared by kernel
		 */
		cxt->loopdev_fd = loopcxt_get_fd(&lc);
		loopcxt_set_fd(&lc, -1, 0);
	}
done:
	loopcxt_deinit(&lc);
	return rc;
}
Ejemplo n.º 11
0
/*
 * Allocates utab entry (upd->fs) for mount/remount. This function should be
 * called *before* mount(2) syscall. The @fs is used as a read-only template.
 *
 * Returns: 0 on success, negative number on error, 1 if utabs update is
 *          unnecessary.
 */
static int utab_new_entry(struct libmnt_update *upd, struct libmnt_fs *fs,
			  unsigned long mountflags)
{
	int rc = 0;
	const char *o = NULL, *a = NULL;
	char *u = NULL;

	assert(fs);
	assert(upd);
	assert(upd->fs == NULL);
	assert(!(mountflags & MS_MOVE));

	DBG(UPDATE, mnt_debug("prepare utab entry"));

	o = mnt_fs_get_user_options(fs);
	a = mnt_fs_get_attributes(fs);
	upd->fs = NULL;

	if (o) {
		/* remove non-mtab options */
		rc = mnt_optstr_get_options(o, &u,
				mnt_get_builtin_optmap(MNT_USERSPACE_MAP),
				MNT_NOMTAB);
		if (rc)
			goto err;
	}

	if (!u && !a) {
		DBG(UPDATE, mnt_debug("utab entry unnecessary (no options)"));
		return 1;
	}

	/* allocate the entry */
	upd->fs = mnt_copy_fs(NULL, fs);
	if (!upd->fs) {
		rc = -ENOMEM;
		goto err;
	}

	rc = mnt_fs_set_options(upd->fs, u);
	if (rc)
		goto err;
	rc = mnt_fs_set_attributes(upd->fs, a);
	if (rc)
		goto err;

	if (!(mountflags & MS_REMOUNT)) {
		rc = set_fs_root(upd, fs, mountflags);
		if (rc)
			goto err;
	}

	free(u);
	DBG(UPDATE, mnt_debug("utab entry OK"));
	return 0;
err:
	free(u);
	mnt_free_fs(upd->fs);
	upd->fs = NULL;
	return rc;
}