X-Git-Url: http://git.grml.org/?a=blobdiff_plain;f=scripts%2Flive-helpers;h=d8bd613998356a74160a341ff8d89005c810bf0a;hb=161e3e634a4f975f4d72fc2cfd715d9741fe9d16;hp=abdfd64906ea80ff17b0c3fa65e9d678f07bdb5d;hpb=b78990c495520b41ce163a55dee2d002ebba10de;p=live-boot-grml.git

diff --git a/scripts/live-helpers b/scripts/live-helpers
index abdfd64..d8bd613 100644
--- a/scripts/live-helpers
+++ b/scripts/live-helpers
@@ -514,12 +514,38 @@ get_fstype ()
 where_is_mounted ()
 {
 	device=${1}
+	# return first found
+	grep -m1 "^${device} " /proc/mounts | cut -f2 -d ' '
+}
 
-	if grep -q "^${device} " /proc/mounts
-	then
-		# return the first found
-		grep -m1 "^${device} " /proc/mounts | cut -f2 -d ' '
-	fi
+trim_path () {
+    # remove all unnecessary /:s in the path, including last one (except
+    # if path is just "/")
+    echo ${1} | sed 's|//\+|/|g' | sed 's|^\(.*[^/]\)/$|\1|'
+}
+
+what_is_mounted_on ()
+{
+	local dir="$(trim_path ${1})"
+	grep -m1 "^[^ ]\+ ${dir} " /proc/mounts | cut -d' ' -f1
+}
+
+chown_ref ()
+{
+	local reference="${1}"
+	shift
+	local targets=${@}
+	local owner=$(stat -c %u:%g "${reference}")
+	chown -h ${owner} ${targets}
+}
+
+chmod_ref ()
+{
+	local reference="${1}"
+	shift
+	local targets=${@}
+	local rights=$(stat -c %a "${reference}")
+	chmod ${rights} ${targets}
 }
 
 lastline ()
@@ -711,6 +737,68 @@ try_mount ()
 	fi
 }
 
+mount_persistent_media ()
+{
+	local device=${1}
+	local backing=""
+
+	# We can't mount into ${rootmnt}/live before ${rootmnt} has been
+	# mounted since that would cover our mountpoint.
+	if [ -n "${rootmnt}" ] && [ -z "$(what_is_mounted_on ${rootmnt})" ]
+	then
+		backing="/$(basename ${device})-backing"
+	else
+		backing="${rootmnt}/live/persistent/$(basename ${device})"
+	fi
+
+	mkdir -p "${backing}"
+	local old_backing="$(where_is_mounted ${device})"
+	if [ -z "${old_backing}" ]
+	then
+		local fstype="$(get_fstype ${device})"
+		local mount_opts="rw,noatime"
+		if [ -n "${PERSISTENT_READONLY}" ]
+		then
+			mount_opts="ro,noatime"
+		fi
+		if mount -t "${fstype}" -o "${mount_opts}" "${device}" "${backing}" >/dev/null
+		then
+			echo ${backing}
+			return 0
+		else
+			log_warning_msg "Failed to mount persistent media ${device}"
+			return 1
+		fi
+	elif [ "${backing}" != "${old_backing}" ]
+	then
+		if mount --move ${old_backing} ${backing} >/dev/null
+		then
+			echo ${backing}
+			return 0
+		else
+			log_warning_msg "Failed to move persistent media ${device}"
+			return 1
+		fi
+	fi
+	return 0
+}
+
+close_persistent_media () {
+	local device=${1}
+	local backing="$(where_is_mounted ${device})"
+
+	if [ -d "${backing}" ]
+	then
+		umount "${backing}" >/dev/null 2>&1
+		rmdir "${backing}" >/dev/null 2>&1
+	fi
+
+	if is_active_luks_mapping ${device}
+	then
+		/sbin/cryptsetup luksClose ${device}
+	fi
+}
+
 open_luks_device ()
 {
 	dev="${1}"
@@ -721,6 +809,21 @@ open_luks_device ()
 		opts="${opts} --readonly"
 	fi
 
+	if /sbin/cryptsetup status "${name}" >/dev/null 2>&1
+	then
+		re="^[[:space:]]*device:[[:space:]]*\([^[:space:]]*\)$"
+		opened_dev=$(cryptsetup status ${name} 2>/dev/null | grep "${re}" | sed "s|${re}|\1|")
+		if [ "${opened_dev}" = "${dev}" ]
+		then
+			luks_device="/dev/mapper/${name}"
+			echo ${luks_device}
+			return 0
+		else
+			log_warning_msg "Cannot open luks device ${dev} since ${opened_dev} already is opened with its name"
+			return 1
+		fi
+	fi
+
 	load_keymap
 
 	while true
@@ -746,12 +849,14 @@ open_luks_device ()
 	done
 }
 
-get_gpt_name () {
+get_gpt_name ()
+{
     local dev="${1}"
     /sbin/blkid -s PART_ENTRY_NAME -p -o value ${dev} 2>/dev/null
 }
 
-is_gpt_device () {
+is_gpt_device ()
+{
     local dev="${1}"
     [ "$(/sbin/blkid -s PART_ENTRY_SCHEME -p -o value ${dev} 2>/dev/null)" = "gpt" ]
 }
@@ -762,22 +867,31 @@ probe_for_gpt_name ()
 	local snapshots="${2}"
 	local dev="${3}"
 
-	if ! is_gpt_device ${dev} || \
-	   ( echo ${PERSISTENT_ENCRYPTION} | grep -qve "\<luks\>" && \
-	     /sbin/cryptsetup isLuks ${dev} > /dev/null 2>&1 )
+	local gpt_dev="${dev}"
+	if is_active_luks_mapping ${dev}
+	then
+		# if $dev is an opened luks device, we need to check
+		# GPT stuff on the backing device
+		gpt_dev=$(get_luks_backing_device "${dev}")
+	fi
+
+	if ! is_gpt_device ${gpt_dev}
 	then
 		return
 	fi
+
+	local gpt_name=$(get_gpt_name ${gpt_dev})
 	for label in ${overlays} ${snapshots}
 	do
-		if [ "$(get_gpt_name ${dev})" = "${label}" ]
+		if [ "${gpt_name}" = "${label}" ]
 		then
 			echo "${label}=${dev}"
 		fi
 	done
 }
 
-probe_for_fs_label () {
+probe_for_fs_label ()
+{
 	local overlays="${1}"
 	local snapshots="${2}"
 	local dev="${3}"
@@ -791,44 +905,45 @@ probe_for_fs_label () {
 	done
 }
 
-probe_for_file_name () {
+probe_for_file_name ()
+{
 	local overlays="${1}"
 	local snapshots="${2}"
 	local dev="${3}"
 
-	local devfstype="$(get_fstype ${dev})"
-	local backing="${rootmnt}/live/persistent/$(basename ${dev})"
 	local ret=""
-	if is_supported_fs ${devfstype} && mkdir -p "${backing}" && \
-	   try_mount "${dev}" "${backing}" "rw" "${devfstype}"
+	local backing="$(mount_persistent_media ${dev})"
+	if [ -z "${backing}" ]
 	then
-		for label in ${overlays}
+	    return
+	fi
+
+	for label in ${overlays}
+	do
+		path=${backing}/${PERSISTENT_PATH}${label}
+		if [ -f "${path}" ]
+		then
+			local loopdev=$(setup_loop "${path}" "loop" "/sys/block/loop*")
+			ret="${ret} ${label}=${loopdev}"
+		fi
+	done
+	for label in ${snapshots}
+	do
+		for ext in squashfs cpio.gz ext2 ext3 ext4 jffs2
 		do
-			path=${backing}/${PERSISTENT_PATH}${label}
-			if [ -f "${path}" ]
+			path="${PERSISTENT_PATH}${label}.${ext}"
+			if [ -f "${backing}/${path}" ]
 			then
-				local loopdev=$(setup_loop "${path}" "loop" "/sys/block/loop*")
-				ret="${ret} ${label}=${loopdev}"
+				ret="${ret} ${label}=${dev}:${backing}:${path}"
 			fi
 		done
-		for label in ${snapshots}
-		do
-			for ext in squashfs cpio.gz ext2 ext3 ext4 jffs2
-			do
-				path="${PERSISTENT_PATH}${label}.${ext}"
-				if [ -f "${backing}/${path}" ]
-				then
-					ret="${ret} ${label}=${dev}:${backing}:${path}"
-				fi
-			done
-		done
+	done
 
-		if [ -n "${ret}" ]
-		then
-			echo ${ret}
-		else
-			umount ${backing} > /dev/null 2>&1 || true
-		fi
+	if [ -n "${ret}" ]
+	then
+		echo ${ret}
+	else
+		umount ${backing} > /dev/null 2>&1 || true
 	fi
 }
 
@@ -857,26 +972,23 @@ find_persistent_media ()
 
 	local overlays="${1}"
 	local snapshots="${2}"
-	local black_listed_devices="${3}"
-	local white_listed_devices="${4}"
+	local white_listed_devices="${3}"
 	local ret=""
 
-	for dev in $(storage_devices "${black_listed_devices}" "${white_listed_devices}")
+	for dev in $(storage_devices "" "${white_listed_devices}")
 	do
 		local result=""
 
-		local real_dev=""
 		local luks_device=""
 		# Check if it's a luks device; we'll have to open the device
 		# in order to probe any filesystem it contains, like we do
-		# below. do_custom_mounts() also depends on that any luks
+		# below. activate_custom_mounts() also depends on that any luks
 		# device already has been opened.
 		if echo ${PERSISTENT_ENCRYPTION} | grep -qe "\<luks\>" && \
-		   /sbin/cryptsetup isLuks ${dev} >/dev/null 2>&1
+		   is_luks_partition ${dev}
 		then
 			if luks_device=$(open_luks_device "${dev}")
 			then
-				real_dev="${dev}"
 				dev="${luks_device}"
 			else
 				# skip $dev since we failed/chose not to open it
@@ -891,15 +1003,7 @@ find_persistent_media ()
 		# Probe for matching GPT partition names or filesystem labels
 		if echo ${PERSISTENT_STORAGE} | grep -qe "\<filesystem\>"
 		then
-			local gpt_dev="${dev}"
-			if [ -n "${luks_device}" ]
-			then
-				# When we probe GPT partitions we need to look
-				# at the real device, not the virtual, opened
-				# luks device
-				gpt_dev="${real_dev}"
-			fi
-			result=$(probe_for_gpt_name "${overlays}" "${snapshots}" ${gpt_dev})
+			result=$(probe_for_gpt_name "${overlays}" "${snapshots}" ${dev})
 			if [ -n "${result}" ]
 			then
 				ret="${ret} ${result}"
@@ -927,7 +1031,7 @@ find_persistent_media ()
 
 		# Close luks device if it isn't used
 		if [ -z "${result}" ] && [ -n "${luks_device}" ] && \
-		   /sbin/cryptsetup status "${luks_device}" 1> /dev/null 2>&1
+		   is_active_luks_mapping "${luks_device}"
 		then
 			/sbin/cryptsetup luksClose "${luks_device}"
 		fi
@@ -957,17 +1061,22 @@ get_mac ()
 	echo ${mac}
 }
 
-is_luks()
+is_luks_partition ()
 {
-    devname="${1}"
-    if [ -x /sbin/cryptsetup ]
-    then
-	/sbin/cryptsetup isLuks "${devname}" 2>/dev/null || ret=${?}
-	return ${ret}
-    else
-	return 1
-    fi
+	device="${1}"
+	/sbin/cryptsetup isLuks "${device}" 1>/dev/null 2>&1
+}
 
+is_active_luks_mapping ()
+{
+	device="${1}"
+	/sbin/cryptsetup status "${device}" 1>/dev/null 2>&1
+}
+
+get_luks_backing_device () {
+	device=${1}
+	cryptsetup status ${device} 2> /dev/null | \
+		awk '{if ($1 == "device:") print $2}'
 }
 
 removable_dev ()
@@ -1055,41 +1164,43 @@ link_files ()
 
 	# This check can only trigger on the inital, non-recursive call since
 	# we create the destination before recursive calls
-	if [ ! -d "${dest_dir}" ];
+	if [ ! -d "${dest_dir}" ]
 	then
 		log_warning_msg "Must link_files into a directory"
 		return
 	fi
 
-	find "${src_dir}" -mindepth 1 -maxdepth 1 | while read x; do
-		local src="${x}"
-		local dest="${dest_dir}$(basename "${x}")"
-		if [ -d "${src}" ];
+	find "${src_dir}" -mindepth 1 -maxdepth 1 | while read src; do
+		local dest="${dest_dir}$(basename "${src}")"
+		if [ -d "${src}" ]
 		then
-			if [ -z "$(ls -A "${src}")" ];
+			if [ -z "$(ls -A "${src}")" ]
 			then
 				continue
 			fi
-			if [ ! -d "${dest}" ];
+			if [ ! -d "${dest}" ]
 			then
 				mkdir -p "${dest}"
 				prev="$(dirname "${dest}")"
-				chown --reference "${prev}" "${dest}"
-				chmod --reference "${prev}" "${dest}"
+				chown_ref "${prev}" "${dest}"
+				chmod_ref "${prev}" "${dest}"
 			fi
 			link_files "${src}" "${dest}" "${src_mask}"
 		else
+			local final_src=${src}
 			if [ -n "${src_mask}" ]
 			then
-				src="$(echo ${src} | sed "s|^${src_mask}||")"
+				final_src="$(echo ${final_src} | sed "s|^${src_mask}||")"
 			fi
 			rm -rf "${dest}" 2> /dev/null
-			ln -s "${src}" "${dest}"
+			ln -s "${final_src}" "${dest}"
+			chown_ref "${src}" "${dest}"
 		fi
 	done
 }
 
-do_union () {
+do_union ()
+{
 	local unionmountpoint="${1}"	# directory where the union is mounted
 	local unionrw="${2}"		# branch where the union changes are stored
 	local unionro1="${3}"		# first underlying read-only branch (optional)
@@ -1149,18 +1260,18 @@ do_union () {
 	esac
 }
 
-get_custom_mounts () {
+get_custom_mounts ()
+{
 	# Side-effect: leaves $devices with live.persist mounted in ${rootmnt}/live/persistent
 	# Side-effect: prints info to file $custom_mounts
 
-	local devices="${1}"
-	local custom_mounts="${2}" # print result to this file
-	local rootmnt="${3}"       # should be set empty post-live-boot
+	local custom_mounts=${1}
+	shift
+	local devices=${@}
 
-	local bindings="/bindings.list"
-	local links="/links.list"
+	local bindings="/tmp/bindings.list"
+	local links="/tmp/links.list"
 	rm -rf ${bindings} ${links} 2> /dev/null
-	local persistent_backing="${rootmnt}/live/persistent"
 
 	for device in ${devices}
 	do
@@ -1170,68 +1281,49 @@ get_custom_mounts () {
 		fi
 
 		local device_name="$(basename ${device})"
-		local device_used=""
-		# $device may already have been mounted by
-		# probe_for_file_name() in find_persistent_media() ...
-		local backing=$(where_is_mounted ${device})
+		local backing=$(mount_persistent_media ${device})
 		if [ -z "${backing}" ]
 		then
-			# ... otherwise we mount it now
-			backing="${persistent_backing}/${device_name}"
-			mkdir -p "${backing}"
-			local device_fstype="$(get_fstype ${device})"
-			if [ -z "${PERSISTENT_READONLY}" ]
-			then
-				device_mount_opts="rw,noatime"
-			else
-				device_mount_opts="ro,noatime"
-			fi
-			if ! mount -t "${device_fstype}" -o "${device_mount_opts}" "${device}" "${backing}" >/dev/null 2>&1
-			then
-				log_warning_msg "Could not mount persistent media ${device} (${device_fstype})"
-			fi
+			continue
 		fi
+
 		local include_list="${backing}/${persistence_list}"
 		if [ ! -r "${include_list}" ]
 		then
-			umount "${backing}" >/dev/null 2>&1
-			rmdir "${backing}" >/dev/null 2>&1
-			if /sbin/cryptsetup status ${device_name} >/dev/null 2>&1
-			then
-				/sbin/cryptsetup luksClose "${device_name}"
-			fi
 			continue
 		fi
 
-		[ "${DEBUG}" = "Yes" ] && cp ${include_list} ${persistent_backing}/${persistence_list}.${device_name}
-		while read source dest options # < ${include_list}
+		if [ -n "${DEBUG}" ] && [ -e "${include_list}" ]
+		then
+			cp ${include_list} ${rootmnt}/live/persistent/${persistence_list}.${device_name}
+		fi
+
+		while read dir options # < ${include_list}
 		do
-			if echo ${source} | grep -qe "^[[:space:]]*\(#.*\)\?$"
+			if echo ${dir} | grep -qe "^[[:space:]]*\(#.*\)\?$"
 			then
 				# skipping empty or commented lines
 				continue
 			fi
 
-			if echo ${dest} | grep -qe "^[^/]"
-			then
-				options="${dest}"
-				dest="${source}"
-			elif [ -z "${dest}" ]
-			then
-				dest="${source}"
-			fi
-
-			if echo ${dest} | grep -qe "^/\+$\|^/\+live\(/.*\)\?$"
+			if trim_path ${dir} | grep -q -e "^[^/]" -e "^/$" -e "^/live\(/.*\)\?$" -e "^/\(.*/\)\?\.\.\?\(/.*\)\?$"
 			then
-				# mounting on / or /live could cause trouble
-				log_warning_msg "Skipping unsafe custom mount on ${dest}"
+				log_warning_msg "Skipping unsafe custom mount ${dir}: must be an absolute path containing neither the \".\" nor \"..\" special dirs, and cannot be \"/live\" (or any sub-directory therein) or \"/\" (for the latter, use ${root_overlay_label}-type persistence)"
 				continue
 			fi
 
+			local opt_source=""
+			local opt_linkfiles=""
 			for opt in $(echo ${options} | tr ',' ' ');
 			do
 				case "${opt}" in
-					linkfiles|union)
+					source=*)
+						opt_source=${opt#source=}
+						;;
+					linkfiles)
+						opt_linkfiles="yes"
+						;;
+					union|bind)
 						;;
 					*)
 						log_warning_msg "Skipping custom mount with unkown option: ${opt}"
@@ -1240,99 +1332,113 @@ get_custom_mounts () {
 				esac
 			done
 
-			# FIXME: handle case: we already have /a/b in
-			# $bindings added from current $device, but
-			# now we find /a -- /a should replace /a/b in
-			# $bindings.
-
-			# FIXME: handle case: we have /a in $bindings
-			# from current $device, now we find /a/b, so
-			# we skip /a/b
+			local source="${dir}"
+			if [ -n "${opt_source}" ]
+			then
+				if echo ${opt_source} | grep -q -e "^/" -e "^\(.*/\)\?\.\.\?\(/.*\)\?$" && [ "${source}" != "." ]
+				then
+					log_warning_msg "Skipping unsafe custom mount with option source=${opt_source}: must be either \".\" (the media root) or a relative path w.r.t. the media root that contains neither comas, nor the special \".\" and \"..\" path components"
+					continue
+				else
+					source="${opt_source}"
+				fi
+			fi
 
-			# ensure that no multiple-/ occur in paths
-			local full_source="$(echo ${backing}/${source}/ | sed -e 's|/\+|/|g')"
-			local full_dest="$(echo ${rootmnt}/${dest}/ | sed -e 's|/\+|/|g')"
-			device_used="yes"
-			if echo ${options} | grep -qe "\<linkfiles\>";
+			local full_source="$(trim_path ${backing}/${source})"
+			local full_dest="$(trim_path ${rootmnt}/${dir})"
+			if [ -n "${opt_linkfiles}" ]
 			then
-				echo "${full_source} ${full_dest} ${options}" >> ${links}
+				echo "${device} ${full_source} ${full_dest} ${options}" >> ${links}
 			else
-				echo "${full_source} ${full_dest} ${options}" >> ${bindings}
+				echo "${device} ${full_source} ${full_dest} ${options}" >> ${bindings}
 			fi
 		done < ${include_list}
-
-		if [ -z "${device_used}" ]
-		then
-			# this device was not used for / earlier, or
-			# custom mount point now, so it's useless
-			umount "${backing}"
-			rmdir "${backing}"
-		fi
 	done
 
 	# We sort the list according to destination so we're sure that
 	# we won't hide a previous mount. We also ignore duplicate
 	# destinations in a more or less arbitrary way.
-	[ -e "${bindings}" ] && sort -k2 -sbu ${bindings} >> ${custom_mounts} && rm ${bindings}
+	[ -e "${bindings}" ] && sort -k3 -sbu ${bindings} >> ${custom_mounts} && rm ${bindings}
 
 	# After all mounts are considered we add symlinks so they
 	# won't be hidden by some mount.
-	[ -e "${links}" ] && sort -k2 -sbu ${links} >> ${custom_mounts} && rm ${links}
+	[ -e "${links}" ] && cat ${links} >> ${custom_mounts} && rm ${links}
+
+	# We need to make sure that no two custom mounts have the same sources
+	# or are nested; if that is the case, too much weird stuff can happen.
+	local prev_source="impossible source" # first iteration must not match
+	local prev_dest=""
+	# This sort will ensure that a source /a comes right before a source
+	# /a/b so we only need to look at the previous source
+	sort -k2 -b ${custom_mounts} |
+	while read device source dest options
+	do
+		if echo ${source} | grep -qe "^${prev_source}\(/.*\)\?$"
+		then
+			panic "Two persistent mounts have the same or nested sources: ${source} on ${dest}, and ${prev_source} on ${prev_dest}"
+		fi
+		prev_source=${source}
+		prev_dest=${dest}
+	done
 }
 
-do_custom_mounts () {
+activate_custom_mounts ()
+{
 	local custom_mounts="${1}" # the ouput from get_custom_mounts()
-	local rootmnt="${2}"       # should be set empty post-live-boot
+	local used_devices=""
 
-	while read source dest options # < ${custom_mounts}
+	while read device source dest options # < ${custom_mounts}
 	do
+		local opt_bind="yes"
 		local opt_linkfiles=""
 		local opt_union=""
 		for opt in $(echo ${options} | tr ',' ' ');
 		do
-			 case "${opt}" in
+			case "${opt}" in
+				bind)
+					opt_bind="yes"
+					unset opt_linkfiles opt_union
+					;;
 				linkfiles)
 					opt_linkfiles="yes"
+					unset opt_bind opt_union
 					;;
 				union)
 					opt_union="yes"
+					unset opt_bind opt_linkfiles
 					;;
 			esac
 		done
 
-		if mountpoint -q "${dest}";
+		if [ -n "$(what_is_mounted_on "${dest}")" ]
 		then
-			log_warning_msg "Skipping custom mount ${source} on ${dest}: destination is already a mount point"
+			log_warning_msg "Skipping custom mount ${dest}: $(what_is_mounted_on "${dest}") is already mounted there"
 			continue
 		fi
 
-		# FIXME: we don't handle already existing
-		# non-directory files in the paths of both $source and
-		# $dest.
-
 		if [ ! -d "${dest}" ]
 		then
-			# if ${dest} is in /home/$user, try fixing
-			# proper ownership
-			# FIXME: this should really be handled by
-			# live-config since we don't know for sure
-			# which uid a certain user has until then
-			if echo ${dest} | grep -qe "^${rootmnt}/*home/\+[^/]\+"
-			then
-				path="/"
-				for dir in $(echo ${dest} | sed -e 's|/\+| |g')
-				do
-					path=${path}/${dir}
-					if [ ! -e ${path} ]
+			# create the destination and delete existing files in
+			# its path that are in the way
+			path="/"
+			for dir in $(echo ${dest} | sed -e 's|/\+| |g')
+			do
+				path=$(trim_path ${path}/${dir})
+				if [ -f ${path} ]
+				then
+					rm -f ${path}
+				fi
+				if [ ! -e ${path} ]
+				then
+					mkdir -p ${path}
+					if echo ${path} | grep -qe "^${rootmnt}/*home/[^/]\+"
 					then
-						mkdir -p ${path}
-						# assume that the intended user is the first, which is usually the case
+						# if ${dest} is in /home try fixing proper ownership by assuming that the intended user is the first, which is usually the case
+						# FIXME: this should really be handled by live-config since we don't know for sure which uid a certain user has until then
 						chown 1000:1000 ${path}
 					fi
-				done
-			else
-				mkdir -p ${dest}
-			fi
+				fi
+			done
 		fi
 
 		# if ${source} doesn't exist on our persistent media
@@ -1341,20 +1447,26 @@ do_custom_mounts () {
 		# dealing with /etc or other system dir.
 		if [ ! -d "${source}" ]
 		then
-			if [ -n "${PERSISTENT_READONLY}" ] || [ -n "${opt_linkfiles}" ]
+			if [ -n "${PERSISTENT_READONLY}" ]
 			then
 				continue
-			elif [ -n "${opt_union}" ]
+			elif [ -n "${opt_union}" ] || [ -n "${opt_linkfiles}" ]
+			then
+				# unions and don't need to be bootstrapped
+				# linkfiles dirs can't be bootstrapped in a sensible way
+				mkdir -p "${source}"
+				chown_ref "${dest}" "${source}"
+				chmod_ref "${dest}" "${source}"
+			elif [ -n "${opt_bind}" ]
 			then
-				# union's don't need to be bootstrapped
-				mkdir "${source}"
-			else
 				# ensure that $dest is not copied *into* $source
 				mkdir -p "$(dirname ${source})"
 				cp -a "${dest}" "${source}"
 			fi
 		fi
 
+		# XXX: If CONFIG_AUFS_ROBR is added to the Debian kernel we can
+		# ignore the loop below and set rofs_dest_backing=$dest
 		rofs_dest_backing=""
 		for d in ${rootmnt}/live/rofs/*
 		do
@@ -1363,7 +1475,6 @@ do_custom_mounts () {
 				rofs_dest_backing="${d}/$(echo ${dest} | sed -e "s|${rootmnt}||")"
 			else
 				rofs_dest_backing="${d}/${dest}"
-
 			fi
 			if [ -d "${rofs_dest_backing}" ]
 			then
@@ -1398,7 +1509,16 @@ do_custom_mounts () {
 			else
 				cow_dir="/live/cow/${dest}"
 			fi
+			if [ -e "${cow_dir}" ]
+			then
+				# If an earlier custom mount has files here
+				# it will "block" the current mount's files
+				# which is undesirable
+				rm -rf "${cow_dir}"
+			fi
 			mkdir -p ${cow_dir}
+			chown_ref "${source}" "${cow_dir}"
+			chmod_ref "${source}" "${cow_dir}"
 			do_union ${dest} ${cow_dir} ${source} ${rofs_dest_backing}
 		fi
 
@@ -1409,7 +1529,14 @@ do_custom_mounts () {
 
 		PERSISTENCE_IS_ON="1"
 		export PERSISTENCE_IS_ON
+
+		if echo ${used_devices} | grep -qve "^\(.* \)\?${device}\( .*\)\?$"
+		then
+			used_devices="${used_devices} ${device}"
+		fi
 	done < ${custom_mounts}
+
+	echo ${used_devices}
 }
 
 fix_home_rw_compatibility ()
@@ -1421,15 +1548,9 @@ fix_home_rw_compatibility ()
 		return
 	fi
 
-	local backing="$(where_is_mounted ${device})"
+	local backing="$(mount_persistent_media ${device})"
 	if [ -z "${backing}" ]
 	then
-		backing="${rootmnt}/live/persistent/$(basename ${device})"
-		mkdir -p "${backing}"
-		local device_fstype="$(get_fstype ${device})"
-	local device_mount_opts="rw,noatime"
-	if ! mount -t "${device_fstype}" -o "${device_mount_opts}" "${device}" "${backing}" >/dev/null 2>&1
-	then
 		return
 	fi
 
@@ -1437,6 +1558,6 @@ fix_home_rw_compatibility ()
 	if [ ! -r "${include_list}" ]
 	then
 		echo "# home-rw backwards compatibility:
-. /home" > "${include_list}"
+/home source=." > "${include_list}"
 	fi
 }