main/openrc: refactor modloop to not depend on alpine_dev boot opt

We scan all relevant mount points for the modloop specified with the
modloop boot option. If modloop boot option is missing, then we warn
about it, look for files that blkid recognizes, try mount them and then
look for modules/$(uname -r).

Wen unmounting, find the loop device, and the backing_file and the
mountpoint that holds the backing file.

1 files changed, 62 insertions, 85 deletions

diff --git a/main/openrc/modloop.initd b/main/openrc/modloop.initd
index 2e7331be11..6bd2e8a2f5 100644
--- a/main/openrc/modloop.initd
+++ b/main/openrc/modloop.initd
@@ -11,115 +11,89 @@ depend() {
 # read kernel options
 init_KOPT() {
 	eval set -- $(cat /proc/cmdline 2>/dev/null)
-	# in case syslinux does not set BOOT_IMAGE
-	KOPT_BOOT_IMAGE="${1}"
 	for opt; do
 	        case "$opt" in
-			alpine_dev=*|modloop=*|BOOT_IMAGE=*)
+			modloop=*)
 				eval "KOPT_${opt%%=*}='${opt#*=}'" ;;
-        	esac
+		esac
 	done
 }
 
-resolve_dev() {
-	case "$1" in
-	UUID=*|LABEL=*) findfs "$1";;
-	*) readlink -f "$1";;
-	esac
+mountdirs() {
+	awk '$2 !~ /^\/(sys|proc|dev|run)/ && $2 != "/" {print $2}' /proc/mounts
 }
 
-find_mnt() {
-	local search_dev="$1" fstab="$2"
-	local dev mnt fs mntopts chk
-	case "$search_dev" in
-		UUID=*|LABEL=*|/dev/*);;
-		nfs) search_dev="${KOPT_alpine_dev#nfs:}";;
-		*) search_dev=/dev/$search_dev;;
-	esac
-	local search_real_dev=$(resolve_dev $search_dev)
-	while read dev mnt fs mntopts chk; do
-		local real_dev=$(resolve_dev $dev)
-		local i j
-		for i in "$search_dev" "$search_real_dev"; do
-			[ -z "$i" ] && continue
-			for j in "$dev" "$real_dev"; do
-				[ -z "$j" ] && continue
-				if [ "$i" = "$j" ]; then
-					echo "$mnt"
-					return
-				fi
-			done
-		done
-	done < $fstab 2>/dev/null
+find_modloop() {
+	local dir="$1"
+	local kver=$(uname -r)
+	local oifs="$IFS"
+	IFS=$'\n'
+	set -- $(blkid "$dir"/boot/* "$dir"/*)
+	IFS="$oifs"
+	for line; do
+		img=${line%%:*}
+		mount "$img" -o loop,ro /.modloop || continue
+		if [ -d /.modloop/modules/$kver ]; then
+			return 0
+		fi
+		umount /.modloop
+	done
+	return 1
 }
 
-# initialies: alpine_dev, alpine_mnt, alpine_fs, alpine_mounted
-find_media() {
-	init_KOPT
-	[ -z "$KOPT_alpine_dev" ] && return 0
-	alpine_mounted=
-	alpine_dev=${KOPT_alpine_dev%%:*}
-	alpine_fs=${KOPT_alpine_dev#*:}
-	[ "$alpine_fs" = "$KOPT_alpine_dev" ] && unset alpine_fs
-	# first we check if alpine_dev is mounted and use this
-	alpine_mnt=$(find_mnt $alpine_dev /proc/mounts)
-	if [ -z "$alpine_mnt" ]; then
-		# then we check fstab
-		alpine_mnt=$(find_mnt $alpine_dev /etc/fstab)
-	else
-		alpine_mounted=yes
+find_backing_file() {
+	local dir="$1"
+	local dev=$(df -P "$dir" | tail -1 | awk '{print $1}')
+	cat /sys/block/${dev#/dev/}/loop/backing_file 2>/dev/null
+}
+
+find_alpine_mnt() {
+	local img="$(find_backing_file $1)"
+	if [ -n "$img" ]; then
+		df -P "$img" | tail -1 | awk '{print $6}'
 	fi
-	# finally we fallback to /media/<devicename>
-	[ -z "$alpine_mnt" ] && alpine_mnt=/media/$alpine_dev
 }
 
 start() {
 	local modloop= mount_opts= modloop_dldir="/lib"
 
-	find_media
-
+	mkdir -p /.modloop /lib
 	case "$KOPT_modloop" in
 		http://*|https://|ftp://*)
 			wget -P "$modloop_dldir" "$KOPT_modloop" \
 				&& modloop=$modloop_dldir/$(basename $KOPT_modloop)
 			;;
+		"")
+			ewarn "WARNING! modloop boot option is missing."
+			;;
 		*)
-			if [ -z "$alpine_dev" ]; then
-				return 0
-			fi
-			if [ -z "$alpine_mounted" ]; then
-				ebegin "Mounting $alpine_mnt"
-				[ -n "$alpine_fs" ] && mount_opts="-t $alpine_fs"
-				mount $mount_opts /dev/$alpine_dev $alpine_mnt 2>/dev/null
-				eend $? || return 1
-			fi
-
-			bootimagedir=${KOPT_BOOT_IMAGE%/*}
-			bootdir=${alpine_mnt}${bootimagedir}
-			kver=$(uname -r)
-			case $kver in
-			*-rc[0-9]) kflavor=vanilla;;
-			*-[a-z]*)  kflavor=${kver##*-};;
-			*)         kflavor=vanilla;;
-			esac
-			for modloop in ${alpine_mnt}$KOPT_modloop \
-				${bootdir}/modloop-$kver \
-				${bootdir}/modloop-$kflavor \
-				${bootdir}/modloop \
-				${alpine_mnt}/boot/modloop-$kver \
-				${alpine_mnt}/boot/modloop-$kflavor \
-				${alpine_mnt}/boot/modloop \
-				${alpine_mnt}$KOPT_BOOT_IMAGE.modloop.*; do
-
-				[ -f "$modloop" -o -n "$KOPT_modloop" ] && break
+			for dir in $(mountdirs); do
+				if [ -f "$dir"/$KOPT_modloop ]; then
+					modloop="$dir/${KOPT_modloop##/}"
+					alpine_mnt="$dir"
+					break
+				fi
 			done
 			;;
 	esac
 
 	ebegin "Mounting modloop $modloop"
-	mkdir -p /.modloop /lib
-	mount -o loop,ro $fs_opt $modloop /.modloop
-	eend $? || return 1
+	if [ -n "$modloop" ]; then
+		mount -o loop,ro $modloop /.modloop
+		eend $? || return 1
+	else
+		for dir in $(mountdirs); do
+			if find_modloop "$dir"; then
+				alpine_mnt="$dir"
+				break
+			fi
+		done
+		if [ -d /.modloop/modules/$(uname -r) ]; then
+			eend 0
+		else
+			eend 1 || return 1
+		fi
+	fi
 
 	#use unionfs is available and configured
 	if grep -q -w "unionfs$" /proc/filesystems && [ -n "$unionfs_size" ]; then
@@ -146,14 +120,17 @@ start() {
 
 stop() {
 	local rc=0
-	find_media
-	[ -z "$alpine_dev" ] && return 0
+	alpine_mnt=$(find_alpine_mnt /.modloop)
+	if mountinfo --quiet /.modunisonfs/modules && mountinfo --quiet /lib/modules; then
+		umount /lib/modules
+		umount /.modunisonfs/modules
+	fi
 	if mountinfo --quiet /.modloop; then
 		ebegin "Unmounting /.modloop"
 		umount -d /.modloop
 		eend $? || return 1
 	fi
-	if mountinfo --quiet $alpine_mnt; then
+	if [ -n "$alpine_mnt" ] && mountinfo --quiet $alpine_mnt; then
 		ebegin "Unmounting $alpine_mnt"
 		umount $alpine_mnt
 		eend $?