CommonInstaller: find_block() from Magisk

CommonInstaller

@@ -229,39 +229,52 @@ is_mounted () {
 # mount partitions
 ##########################################################################################
 
+toupper() {
+	echo "$@" | tr '[:lower:]' '[:upper:]'
+}
+
 find_block () {
-	unset tmp
-	tmp=$(find /dev/block \( -type b -o -type c -o -type l \) -name ${1}${SLOT} | head -n 1)
-	[ -z "${tmp}" ] && tmp=$(find /dev \( -type b -o -type c -o -type l \) -maxdepth 1 -iname ${1}${SLOT} | head -n 1)
-	if [ -z "${tmp}" ]; then
-		for uevent in /sys/dev/block/*/uevent; do
-			partname=$(awk -F= '/PARTNAME/{print $2}' ${uevent})
-			if [ "${1}${SLOT}" = "${partname}" ]; then
-				tmp="/dev/block/$(awk -F= '/DEVNAME/{print $2}' ${uevent})"
-				break
-			fi
-		done
+	local block tmp partname devname device
+
+	block=${1}${SLOT}
+	device=$(find /dev/block \( -type b -o -type c -o -type l \) -name ${block} | head -n 1)
+
+	if [ ! -z ${device} ]; then
+		readlink -f ${device}
+		return 0
 	fi
-	readlink -f "${tmp}"
+
+	for uevent in /sys/dev/block/*/uevent; do
+		partname=$(awk -F= '/PARTNAME/{print $2}' ${uevent})
+		devname=$(awk -F= '/DEVNAME/{print $2}' ${uevent})
+		if [ "$(toupper ${block})" = "$(toupper ${partname})" ]; then
+			echo /dev/block/${devname}
+			return 0
+		fi
+	done
+
+	device=$(find /dev \( -type b -o -type c -o -type l \) -maxdepth 1 -iname ${block} | head -n 1)
+	if [ ! -z ${device} ]; then
+		readlink -f ${device}
+		return 0
+	fi
+
+	return 1
+
 }
 
 mount_partitions () {
 	if ! ${BOOTMODE}; then
-		DEVICE_AB=FALSE
 		VENDOR_COMPAT=FALSE
 		SYSTEM_AS_ROOT=FALSE
 
 		SLOT=$(grep_cmdline androidboot.slot_suffix)
-		decho " INFO: #1 [SLOT] ${SLOT}"
 		if [ -z ${SLOT} ]; then
 			SLOT=$(grep_cmdline androidboot.slot)
-			echo " INFO: #2 [SLOT] ${SLOT}"
-			if [ ! -z ${SLOT} ]; then
-				SLOT=_${SLOT}
-				echo " INFO: #3 [SLOT] ${SLOT}"
-				DEVICE_AB=TRUE
-			fi
+			[ -z ${SLOT} ] || SLOT=_${SLOT}
 		fi
+		[ -z ${SLOT} ] && DEVICE_AB=FALSE || DEVICE_AB=TRUE
+		decho " INFO: #1 [SLOT] ${SLOT}"
 
 		is_mounted /data || mount /data || decho "failed to mount /data!"
 
@@ -270,6 +283,11 @@ mount_partitions () {
 		SYSTEM_BLOCK=$(find_block system)
 		decho " INFO: #5 [SYSTEM_BLOCK] ${SYSTEM_BLOCK}"
 
+		if is_mounted /system_root; then
+			umount /system 2&>/dev/null
+			umount /system_root 2&>/dev/null
+		fi
+
 		mkdir -p /system /system_root
 		mount -o rw ${SYSTEM_BLOCK} /system