base-files: improve lib/upgrade/common.sh

Recently, upgrade device autodetection has been added to the mvebu target.
This exposes some shortcomings of the generic export_bootdevice function,
e.g. on the Turris Omnia: export_bootdevice silently reports the root
partition to be the boot device. This makes the sysupgrade process fail at
several places.

Fix this by clearly distinguishing between /proc/cmdline arguments which
specify the boot disk, and those which specify the root partition. Only in
the latter case, strip off the partition, and do it consistently.
root=PARTUUID=<pseudo PARTUUID for MBR> (any partition) and root=/dev/*
(any partition) are accepted.

The root of the problem is that the *existing* export_bootdevice in
/lib/upgrade/common.sh behaves differently, if the kernel is booted with
root=/dev/..., or if it is booted with root=PARTUUID=...

In the former case, it reports back major/minor of the root partition,
in the latter case it reports back major/minor of the complete boot disk.

Targets, which boot with root=/dev/... *and* use export_bootdevice /
export_partdevice, have added workarounds to this behaviour, by specifying
*negative* increments to the export_partdevice function.

Consequently, those targets have to be adapted to use positive increments,
otherwise they are broken by the change to export_bootdevice.

Fixes: 4e8345ff68 ("mvebu: base-files: autodetect upgrade device")
Signed-off-by: Klaus Kudielka <klaus.kudielka@gmail.com>
Tested-by: Tomasz Maciej Nowak <tomek_n@o2.pl>

package/base-files/files/lib/upgrade/common.sh

@@ -101,35 +101,41 @@ get_magic_long() {
 }
 
 export_bootdevice() {
-	local cmdline uuid disk uevent line
+	local cmdline bootdisk rootpart uuid blockdev uevent line
 	local MAJOR MINOR DEVNAME DEVTYPE
 
 	if read cmdline < /proc/cmdline; then
 		case "$cmdline" in
 			*block2mtd=*)
-				disk="${cmdline##*block2mtd=}"
-				disk="${disk%%,*}"
+				bootdisk="${cmdline##*block2mtd=}"
+				bootdisk="${bootdisk%%,*}"
 			;;
 			*root=*)
-				disk="${cmdline##*root=}"
-				disk="${disk%% *}"
+				rootpart="${cmdline##*root=}"
+				rootpart="${rootpart%% *}"
 			;;
 		esac
 
-		case "$disk" in
-			PARTUUID=[a-f0-9][a-f0-9][a-f0-9][a-f0-9][a-f0-9][a-f0-9][a-f0-9][a-f0-9]-02)
-				uuid="${disk#PARTUUID=}"
-				uuid="${uuid%-02}"
-				for disk in $(find /dev -type b); do
-					set -- $(dd if=$disk bs=1 skip=440 count=4 2>/dev/null | hexdump -v -e '4/1 "%02x "')
+		case "$bootdisk" in
+			/dev/*)
+				uevent="/sys/class/block/${bootdisk##*/}/uevent"
+			;;
+		esac
+
+		case "$rootpart" in
+			PARTUUID=[a-f0-9][a-f0-9][a-f0-9][a-f0-9][a-f0-9][a-f0-9][a-f0-9][a-f0-9]-[a-f0-9][a-f0-9])
+				uuid="${rootpart#PARTUUID=}"
+				uuid="${uuid%-[a-f0-9][a-f0-9]}"
+				for blockdev in $(find /dev -type b); do
+					set -- $(dd if=$blockdev bs=1 skip=440 count=4 2>/dev/null | hexdump -v -e '4/1 "%02x "')
 					if [ "$4$3$2$1" = "$uuid" ]; then
-						uevent="/sys/class/block/${disk##*/}/uevent"
+						uevent="/sys/class/block/${blockdev##*/}/uevent"
 						break
 					fi
 				done
 			;;
 			/dev/*)
-				uevent="/sys/class/block/${disk##*/}/uevent"
+				uevent="/sys/class/block/${rootpart##*/}/../uevent"
 			;;
 		esac
 

target/linux/apm821xx/base-files/lib/upgrade/wdbook.sh

@@ -7,7 +7,7 @@ mbl_do_platform_check() {
 
 	[ "$#" -gt 1 ] && return 1
 
-	export_bootdevice && export_partdevice diskdev -2 || {
+	export_bootdevice && export_partdevice diskdev 0 || {
 		echo "Unable to determine upgrade device"
 		return 1
 	}
@@ -36,7 +36,7 @@ mbl_do_platform_check() {
 mbl_do_upgrade() {
 	local diskdev partdev diff
 
-	export_bootdevice && export_partdevice diskdev -2 || {
+	export_bootdevice && export_partdevice diskdev 0 || {
 		echo "Unable to determine upgrade device"
 		return 1
 	}
@@ -70,10 +70,6 @@ mbl_do_upgrade() {
 
 	#iterate over each partition from the image and write it to the boot disk
 	while read part start size; do
-		# root is /dev/sd[a|b]2 and not /dev/sd[a|b] this causes some problem
-		# one of which is this offset, I'm not sure what's the best fix, so
-		# here's a WA.
-		let part=$((part - 2))
 		if export_partdevice partdev $part; then
 			echo "Writing image to /dev/$partdev..."
 			get_image "$@" | dd of="/dev/$partdev" ibs="512" obs=1M skip="$start" count="$size" conv=fsync
@@ -90,8 +86,7 @@ mbl_do_upgrade() {
 mbl_copy_config() {
 	local partdev
 
-	# Same as above /dev/sd[a|b]2 is root, so /boot is -1
-	if export_partdevice partdev -1; then
+	if export_partdevice partdev 1; then
 		mount -t ext4 -o rw,noatime "/dev/$partdev" /mnt
 		cp -af "$CONF_TAR" /mnt/
 		umount /mnt

target/linux/brcm2708/base-files/lib/upgrade/platform.sh

@@ -9,7 +9,7 @@ platform_check_image() {
 
 	[ "$#" -gt 1 ] && return 1
 
-	export_bootdevice && export_partdevice diskdev -2 || {
+	export_bootdevice && export_partdevice diskdev 0 || {
 		echo "Unable to determine upgrade device"
 		return 1
 	}
@@ -38,7 +38,7 @@ platform_check_image() {
 platform_do_upgrade() {
 	local diskdev partdev diff
 
-	export_bootdevice && export_partdevice diskdev -2 || {
+	export_bootdevice && export_partdevice diskdev 0 || {
 		echo "Unable to determine upgrade device"
 		return 1
 	}
@@ -72,10 +72,6 @@ platform_do_upgrade() {
 
 	#iterate over each partition from the image and write it to the boot disk
 	while read part start size; do
-		# root is /dev/sd[a|b]2 and not /dev/sd[a|b] this causes some problem
-		# one of which is this offset, I'm not sure what's the best fix, so
-		# here's a WA.
-		let part=$((part - 2))
 		if export_partdevice partdev $part; then
 			echo "Writing image to /dev/$partdev..."
 			get_image "$@" | dd of="/dev/$partdev" ibs="512" obs=1M skip="$start" count="$size" conv=fsync
@@ -92,8 +88,7 @@ platform_do_upgrade() {
 platform_copy_config() {
 	local partdev
 
-	# Same as above /dev/sd[a|b]2 is root, so /boot is -1
-	if export_partdevice partdev -1; then
+	if export_partdevice partdev 1; then
 		mkdir -p /boot
 		[ -f /boot/kernel.img ] || mount -t vfat -o rw,noatime "/dev/$partdev" /boot
 		cp -af "$CONF_TAR" /boot/

target/linux/omap/base-files/lib/preinit/79_move_config

@@ -6,7 +6,7 @@ move_config() {
 
 	. /lib/upgrade/common.sh
 
-	if export_bootdevice && export_partdevice partdev -1; then
+	if export_bootdevice && export_partdevice partdev 1; then
 		if mount -t vfat -o rw,noatime "/dev/$partdev" /mnt; then
 			if [ -f /mnt/sysupgrade.tgz ]; then
 				mv -f /mnt/sysupgrade.tgz /

target/linux/omap/base-files/lib/upgrade/platform.sh

@@ -1,7 +1,7 @@
 platform_check_image() {
 	local diskdev partdev diff
 
-	export_bootdevice && export_partdevice diskdev -2 || {
+	export_bootdevice && export_partdevice diskdev 0 || {
 		echo "Unable to determine upgrade device"
 		return 1
 	}
@@ -28,7 +28,7 @@ platform_check_image() {
 platform_copy_config() {
 	local partdev
 
-	if export_partdevice partdev -1; then
+	if export_partdevice partdev 1; then
 		mount -t vfat -o rw,noatime "/dev/$partdev" /mnt
 		cp -af "$CONF_TAR" /mnt/
 		umount /mnt
@@ -38,7 +38,7 @@ platform_copy_config() {
 platform_do_upgrade() {
 	local diskdev partdev diff
 
-	export_bootdevice && export_partdevice diskdev -2 || {
+	export_bootdevice && export_partdevice diskdev 0 || {
 		echo "Unable to determine upgrade device"
 		return 1
 	}
@@ -74,7 +74,6 @@ platform_do_upgrade() {
 	get_image "$@" | dd of="$diskdev" bs=1024 skip=8 seek=8 count=1016 conv=fsync
 	#iterate over each partition from the image and write it to the boot disk
 	while read part start size; do
-		part="$(($part - 2))"
 		if export_partdevice partdev $part; then
 			echo "Writing image to /dev/$partdev..."
 			get_image "$@" | dd of="/dev/$partdev" ibs="512" obs=1M skip="$start" count="$size" conv=fsync

target/linux/sunxi/base-files/lib/preinit/79_move_config

@@ -6,7 +6,7 @@ move_config() {
 
 	. /lib/upgrade/common.sh
 
-	if export_bootdevice && export_partdevice partdev -1; then
+	if export_bootdevice && export_partdevice partdev 1; then
 		if mount -t vfat -o rw,noatime "/dev/$partdev" /mnt; then
 			if [ -f /mnt/sysupgrade.tgz ]; then
 				mv -f /mnt/sysupgrade.tgz /

target/linux/sunxi/base-files/lib/upgrade/platform.sh

@@ -1,7 +1,7 @@
 platform_check_image() {
 	local diskdev partdev diff
 
-	export_bootdevice && export_partdevice diskdev -2 || {
+	export_bootdevice && export_partdevice diskdev 0 || {
 		echo "Unable to determine upgrade device"
 		return 1
 	}
@@ -28,7 +28,7 @@ platform_check_image() {
 platform_copy_config() {
 	local partdev
 
-	if export_partdevice partdev -1; then
+	if export_partdevice partdev 1; then
 		mount -t vfat -o rw,noatime "/dev/$partdev" /mnt
 		cp -af "$CONF_TAR" /mnt/
 		umount /mnt
@@ -38,7 +38,7 @@ platform_copy_config() {
 platform_do_upgrade() {
 	local diskdev partdev diff
 
-	export_bootdevice && export_partdevice diskdev -2 || {
+	export_bootdevice && export_partdevice diskdev 0 || {
 		echo "Unable to determine upgrade device"
 		return 1
 	}
@@ -74,7 +74,6 @@ platform_do_upgrade() {
 	get_image "$@" | dd of="$diskdev" bs=1024 skip=8 seek=8 count=1016 conv=fsync
 	#iterate over each partition from the image and write it to the boot disk
 	while read part start size; do
-		part="$(($part - 2))"
 		if export_partdevice partdev $part; then
 			echo "Writing image to /dev/$partdev..."
 			get_image "$@" | dd of="/dev/$partdev" ibs="512" obs=1M skip="$start" count="$size" conv=fsync