path: root/common/overlay

#
# overlayfs specific common functions.
#
. ./common/module

# Export overlayfs xattrs and constant value
export OVL_XATTR_OPAQUE="trusted.overlay.opaque"
export OVL_XATTR_REDIRECT="trusted.overlay.redirect"
export OVL_XATTR_IMPURE="trusted.overlay.impure"
export OVL_XATTR_ORIGIN="trusted.overlay.origin"
export OVL_XATTR_NLINK="trusted.overlay.nlink"
export OVL_XATTR_UPPER="trusted.overlay.upper"
export OVL_XATTR_METACOPY="trusted.overlay.metacopy"

if [ -n "$OVL_BASE_FSTYP" ];then
	_source_specific_fs $OVL_BASE_FSTYP
fi

# helper function to do the actual overlayfs mount operation
# accepts "-" as upperdir for non-upper overlayfs
_overlay_mount_dirs()
{
	local lowerdir=$1
	local upperdir=$2
	local workdir=$3
	shift 3
	local diropts="-olowerdir=$lowerdir"

	[ -n "$upperdir" ] && [ "$upperdir" != "-" ] && \
		diropts+=",upperdir=$upperdir,workdir=$workdir"

	$MOUNT_PROG -t overlay $diropts `_common_dev_mount_options $*`
}

# Mount with mnt/dev of scratch mount and custom mount options
_overlay_scratch_mount_opts()
{
	$MOUNT_PROG -t overlay $OVL_BASE_SCRATCH_MNT $SCRATCH_MNT $*
}

# Mount with same options/mnt/dev of scratch mount, but optionally
# with different lower/upper/work dirs
_overlay_scratch_mount_dirs()
{
	local lowerdir=$1
	local upperdir=$2
	local workdir=$3
	shift 3

	_overlay_mount_dirs $lowerdir $upperdir $workdir \
				$* $OVL_BASE_SCRATCH_MNT $SCRATCH_MNT
}

_overlay_mkdirs()
{
	local dir=$1

	mkdir -p $dir/$OVL_UPPER
	mkdir -p $dir/$OVL_LOWER
	mkdir -p $dir/$OVL_WORK
	mkdir -p $dir/$OVL_MNT
}

# Given a base fs dir, set up overlay directories and mount on the given mnt.
# The dir is used as the mount device so it can be seen from df or mount
_overlay_mount()
{
	local dir=$1
	local mnt=$2
	shift 2

	_supports_filetype $dir || _notrun "upper fs needs to support d_type"

	_overlay_mkdirs $dir

	_overlay_mount_dirs $dir/$OVL_LOWER $dir/$OVL_UPPER $dir/$OVL_WORK \
				$* $dir $mnt
}

_overlay_base_mount()
{
	local devname=$1
	local mntname=$2
	local dev=$3
	local mnt=$4
	shift 4

	if [ -z "$dev" -o -z "$mnt" ] || \
		_check_mounted_on $devname $dev $mntname $mnt; then
		_idmapped_mount $dev $mnt
		# no base fs or already mounted
		return 0
	elif [ $? -ne 1 ]; then
		# base fs mounted but not on mount point
		return 1
	fi

	if [ $OVL_BASE_FSTYP ]; then
		_mount -t $OVL_BASE_FSTYP $* $dev $mnt
	else
		_mount $* $dev $mnt
	fi

	_idmapped_mount $dev $mnt
}

_overlay_base_test_mount()
{
	_overlay_base_mount OVL_BASE_TEST_DEV OVL_BASE_TEST_DIR \
			"$OVL_BASE_TEST_DEV" "$OVL_BASE_TEST_DIR" \
			$TEST_FS_MOUNT_OPTS $SELINUX_MOUNT_OPTIONS
}

_overlay_test_mount()
{
	_overlay_base_test_mount && \
		_overlay_mount $OVL_BASE_TEST_DIR $TEST_DIR $*
}

_overlay_base_scratch_mount()
{
	_overlay_base_mount OVL_BASE_SCRATCH_DEV OVL_BASE_SCRATCH_MNT \
			"$OVL_BASE_SCRATCH_DEV" "$OVL_BASE_SCRATCH_MNT" \
			$OVL_BASE_MOUNT_OPTIONS $SELINUX_MOUNT_OPTIONS
}

_overlay_scratch_mount()
{
	if echo "$*" | grep -q remount; then
		$MOUNT_PROG $SCRATCH_MNT $*
		return
	fi

	_overlay_base_scratch_mount && \
		_overlay_mount $OVL_BASE_SCRATCH_MNT $SCRATCH_MNT $*
}

_overlay_base_unmount()
{
	local dev=$1
	local mnt=$2

	[ -n "$dev" -a -n "$mnt" ] || return 0

	$UMOUNT_PROG $mnt
}

_overlay_test_unmount()
{
	$UMOUNT_PROG $TEST_DIR
	_overlay_base_unmount "$OVL_BASE_TEST_DEV" "$OVL_BASE_TEST_DIR"
}

_overlay_scratch_unmount()
{
	$UMOUNT_PROG $SCRATCH_MNT
	_overlay_base_unmount "$OVL_BASE_SCRATCH_DEV" "$OVL_BASE_SCRATCH_MNT"
}

# Check that a specific overlayfs feature is supported
_check_overlay_feature()
{
	local feature=$1
	local dev=$2
	local mnt=$3

	# overalyfs features (e.g. redirect_dir, index) are
	# configurable from Kconfig (the build default), by module
	# parameter (the system default) and per mount by mount
	# option ${feature}=[on|off].
	local default=`_get_fs_module_param ${feature}`
	[ "$default" = Y ] || [ "$default" = N ] || \
		_notrun "feature '${feature}' not supported by ${FSTYP}"

	# Check options to be sure. For example, Overlayfs will fallback to
	# index=off if underlying fs does not support file handles.
	# Overlayfs only displays mount option if it differs from the default.
	# Overlayfs may enable the feature, but fallback to read-only mount.
	((( [ "$default" = N ] && _fs_options $dev | grep -q "${feature}=on" ) || \
	  ( [ "$default" = Y ] && ! _fs_options $dev | grep -q "${feature}=off" )) && \
	    touch $mnt/foo 2>/dev/null ) || \
	        _notrun "${FSTYP} feature '${feature}' cannot be enabled on ${dev}"
}

# Require a set of overlayfs features
_require_scratch_overlay_features()
{
	local features=( $* )
	local opts="rw"

	for feature in ${features[*]}; do
		# If the module parameter does not exist then there is no
		# point in checking the mount option.
		_get_fs_module_param ${feature} > /dev/null 2>&1 || \
			_notrun "feature '${feature}' not supported by overlay"
		opts+=",${feature}=on"
	done

	_scratch_mkfs > /dev/null 2>&1
	_try_scratch_mount -o $opts || \
	        _notrun "overlay features '${features[*]}' cannot be enabled on ${SCRATCH_DEV}"

	for feature in ${features[*]}; do
		_check_overlay_feature ${feature} $SCRATCH_DEV $SCRATCH_MNT
	done

	_scratch_unmount
}

_check_scratch_overlay_xattr_escapes()
{
	local testfile=$1

	touch $testfile
	! ($GETFATTR_PROG -n trusted.overlay.foo $testfile 2>&1 | grep -E -q "not (permitted|supported)")
}

_require_scratch_overlay_xattr_escapes()
{
	_scratch_mkfs > /dev/null 2>&1
	_scratch_mount

        _check_scratch_overlay_xattr_escapes $SCRATCH_MNT/file || \
                  _notrun "xattr escaping is not supported by overlay"

	_scratch_unmount
}

_require_scratch_overlay_verity()
{
	local lowerdirs="$OVL_BASE_SCRATCH_MNT/$OVL_UPPER:$OVL_BASE_SCRATCH_MNT/$OVL_LOWER"

	_require_scratch_verity "$OVL_BASE_FSTYP" "$OVL_BASE_SCRATCH_MNT"

	_scratch_mkfs > /dev/null 2>&1
	_overlay_scratch_mount_dirs "$lowerdirs" "-" "-" \
		-o ro,redirect_dir=follow,metacopy=on,verity=on > /dev/null 2>&1 || \
	        _notrun "overlay verity not supported on ${SCRATCH_DEV}"

	_scratch_unmount
}

# Check kernel support for <lowerdirs>::<lowerdatadir> format
_require_scratch_overlay_lowerdata_layers()
{
	local lowerdirs="$OVL_BASE_SCRATCH_MNT/$OVL_UPPER::$OVL_BASE_SCRATCH_MNT/$OVL_LOWER"

	_scratch_mkfs > /dev/null 2>&1
	_overlay_scratch_mount_dirs "$lowerdirs" "-" "-" \
		-o ro,redirect_dir=follow,metacopy=on > /dev/null 2>&1 || \
	        _notrun "overlay data-only layers not supported on ${SCRATCH_DEV}"

	_scratch_unmount
}

# Check kernel support for lowerdir+=<lowerdir>,datadir+=<lowerdatadir> format
_require_scratch_overlay_lowerdir_add_layers()
{
	local lowerdir="$OVL_BASE_SCRATCH_MNT/$OVL_UPPER"
	local datadir="$OVL_BASE_SCRATCH_MNT/$OVL_LOWER"

	_scratch_mkfs > /dev/null 2>&1
	_overlay_scratch_mount_opts \
		-o"lowerdir+=$lowerdir,datadir+=$datadir" \
		-o"redirect_dir=follow,metacopy=on" > /dev/null 2>&1 || \
	        _notrun "overlay lowerdir+,datadir+ not supported on ${SCRATCH_DEV}"

	_scratch_unmount
}

# Helper function to check underlying dirs of overlay filesystem
_overlay_fsck_dirs()
{
	local lowerdir=$1
	local upperdir=$2
	local workdir=$3
	shift 3

	[[ ! -x "$FSCK_OVERLAY_PROG" ]] && return 0

	$FSCK_OVERLAY_PROG -o lowerdir=$lowerdir -o upperdir=$upperdir \
			   -o workdir=$workdir $*
}

# Run fsck and check for expected return value
_overlay_fsck_expect()
{
	# The first arguments is the expected fsck program exit code, the
	# remaining arguments are the input parameters of the fsck program.
	local expect_ret=$1
	local lowerdir=$2
	local upperdir=$3
	local workdir=$4
	shift 4

	_overlay_fsck_dirs $lowerdir $upperdir $workdir $* >> \
			$seqres.full 2>&1
	fsck_ret=$?

	[[ "$fsck_ret" == "$expect_ret" ]] || \
		echo "expect fsck.overlay to return $expect_ret, but got $fsck_ret"
}

_overlay_check_dirs()
{
	local lowerdir=$1
	local upperdir=$2
	local workdir=$3
	shift 3
	local err=0

	_overlay_fsck_dirs $lowerdir $upperdir $workdir \
			   $FSCK_OPTIONS $* >>$tmp.fsck 2>&1
	if [ $? -ne 0 ]; then
		_log_err "_overlay_check_fs: overlayfs on $lowerdir,$upperdir,$workdir is inconsistent"

		echo "*** fsck.overlay output ***"	>>$seqres.full
		cat $tmp.fsck				>>$seqres.full
		echo "*** end fsck.overlay output"	>>$seqres.full

		echo "*** mount output ***"		>>$seqres.full
		_mount					>>$seqres.full
		echo "*** end mount output"		>>$seqres.full

		err=1
	fi
	rm -f $tmp.fsck

	return $err
}

# Check the same mnt/dev of _check_overlay_scratch_fs but non-default
# underlying scratch dirs of overlayfs, it needs lower/upper/work dirs
# provided as arguments, and it's useful for non-default setups such
# as multiple lower layers
_overlay_check_scratch_dirs()
{
	local lowerdir=$1
	local upperdir=$2
	local workdir=$3
	shift 3

	# Need to umount overlay for scratch dir check
	local ovl_mounted=`_is_dir_mountpoint $SCRATCH_MNT`
	[ -z "$ovl_mounted" ] || $UMOUNT_PROG $SCRATCH_MNT

	# Check dirs with extra overlay options
	_overlay_check_dirs $lowerdir $upperdir $workdir $*
	local ret=$?

	if [ $ret -eq 0 -a -n "$ovl_mounted" ]; then
		# overlay was mounted, remount with extra mount options
		_overlay_scratch_mount_dirs $lowerdir $upperdir \
					    $workdir $*
		ret=$?
	fi

	return $ret
}

_overlay_check_fs()
{
	# The first arguments is overlay mount point use for checking
	# overlay filesystem is mounted or not, the remaining arquments
	# use for mounting overlay base filesystem if it was not mounted.
	# We shift one to aligns arguments for _overlay_base_mount.
	local ovl_mnt=$1
	shift 1

	local base_dev=$3
	local base_mnt=$4

	[ "$FSTYP" = overlay ] || return 0

	# Base fs needs to be mounted to check overlay dirs
	local base_fstype=""
	local ovl_mounted=""

	[ -z "$base_dev" ] || \
		base_fstype=`_fs_type $base_dev`

	# If base_dev is set but base_fstype is empty, base fs is not
	# mounted, we need to mount base fs. Otherwise, we need to
	# check and umount overlayfs if it was mounted.
	if [ -n "$base_dev" -a -z "$base_fstype" ]; then
		_overlay_base_mount $*
	else
		# Check and umount overlay for dir check
		ovl_mounted=`_is_dir_mountpoint $ovl_mnt`
		[ -z "$ovl_mounted" ] || $UMOUNT_PROG $ovl_mnt
	fi

	_overlay_check_dirs $base_mnt/$OVL_LOWER $base_mnt/$OVL_UPPER \
			    $base_mnt/$OVL_WORK
	local ret=$?

	if [ -n "$base_dev" -a -z "$base_fstype" ]; then
		_overlay_base_unmount "$base_dev" "$base_mnt"
	elif [ $ret -eq 0 -a -n "$ovl_mounted" ]; then
		# overlay was mounted, remount besides extra mount options
		_overlay_mount $base_mnt $ovl_mnt
		ret=$?
	fi

	if [ $ret != 0 ]; then
		status=1
		if [ "$iam" != "check" ]; then
			exit 1
		fi
		return 1
	fi

	return 0
}

_check_overlay_test_fs()
{
	_overlay_check_fs "$TEST_DIR" \
		OVL_BASE_TEST_DEV OVL_BASE_TEST_DIR \
		"$OVL_BASE_TEST_DEV" "$OVL_BASE_TEST_DIR" \
		$TEST_FS_MOUNT_OPTS $SELINUX_MOUNT_OPTIONS
}

_check_overlay_scratch_fs()
{
	_overlay_check_fs "$SCRATCH_MNT" \
		OVL_BASE_SCRATCH_DEV OVL_BASE_SCRATCH_MNT \
		"$OVL_BASE_SCRATCH_DEV" "$OVL_BASE_SCRATCH_MNT" \
		$OVL_BASE_MOUNT_OPTIONS $SELINUX_MOUNT_OPTIONS
}

_repair_overlay_scratch_fs()
{
	_overlay_fsck_dirs $OVL_BASE_SCRATCH_MNT/$OVL_LOWER \
		$OVL_BASE_SCRATCH_MNT/$OVL_UPPER \
		$OVL_BASE_SCRATCH_MNT/$OVL_WORK -y
	local res=$?
	case $res in
	$FSCK_OK|$FSCK_NONDESTRUCT)
		res=0
		;;
	*)
		_dump_err2 "fsck.overlay failed, err=$res"
		;;
	esac
	return $res
}

# This test requires that unionmount testsuite is installed at
# $UNIONMOUNT_TESTSUITE and that it supports configuring layers and overlay
# mount paths via UNIONMOUNT_* environment variables.
_require_unionmount_testsuite()
{
	[ -x "$UNIONMOUNT_TESTSUITE/run" ] || \
		_notrun "unionmount testsuite required."

	# Verify that UNIONMOUNT_* vars are supported
	local usage=`UNIONMOUNT_BASEDIR=_ "$UNIONMOUNT_TESTSUITE/run" 2>&1`
	echo $usage | grep -wq "UNIONMOUNT_BASEDIR" || \
		_notrun "newer version of unionmount testsuite required."

	[ -n "$OVERLAY_MOUNT_OPTIONS" ] || return
	# If custom overlay mount options are used
	# verify that UNIONMOUNT_MNTOPTIONS var is supported
	local usage=`UNIONMOUNT_MNTOPTIONS=_ "$UNIONMOUNT_TESTSUITE/run" 2>&1`
	echo $usage | grep -wq "UNIONMOUNT_MNTOPTIONS" || \
		_notrun "newer version of unionmount testsuite required to support OVERLAY_MOUNT_OPTIONS."
}

_unionmount_testsuite_run()
{
	[ "$FSTYP" = overlay ] || \
		_notrun "Filesystem $FSTYP not supported with unionmount testsuite."

	# Provide the mounted base fs for upper and lower dirs and the
	# overlay mount point.
	# unionmount testsuite will perform the overlay mount.
	# test fs is used for lower layer in non-samefs runs.
	# scratch fs is used for upper layer in non-samefs runs and
	# for both layers in samefs runs.
	if (echo $* | grep -qv samefs) ; then
		_overlay_base_test_mount
		export UNIONMOUNT_LOWERDIR=$OVL_BASE_TEST_DIR/union
	fi
	export UNIONMOUNT_BASEDIR=$OVL_BASE_SCRATCH_MNT/union
	export UNIONMOUNT_MNTOPTIONS="$OVERLAY_MOUNT_OPTIONS"

	_scratch_mkfs
	rm -rf $UNIONMOUNT_BASEDIR $UNIONMOUNT_LOWERDIR
	mkdir -p $UNIONMOUNT_BASEDIR $UNIONMOUNT_LOWERDIR

	cd $UNIONMOUNT_TESTSUITE
	echo "run $* ..." > $seqres.full
	./run $* >> $seqres.full || \
		echo "unionmount testsuite failed! see $seqres.full for details."
}

_unionmount_testsuite_cleanup()
{
	cd /
	rm -f $tmp.*

	[ -n "$UNIONMOUNT_BASEDIR" ] || return 0

	# Cleanup overlay mount after unionmount testsuite run
	cd $UNIONMOUNT_TESTSUITE
	echo "run --clean-up ..." >> $seqres.full
	./run --clean-up >> $seqres.full 2>&1
}