gluon/patches/openwrt/0026-x86-use-PARTUUID-instead-explicitly-specifying-the-device-by-default.patch

From: Matthias Schiffer <mschiffer@universe-factory.net>
Date: Mon, 23 Mar 2015 21:11:41 +0100
Subject: x86: use PARTUUID instead explicitly specifying the device by default

This changes the x86 image generation to match x86_64, using the PARTUUID for
the rootfs instead of explicitly configuring the device.

It unbreaks KVM with VirtIO, which uses /dev/vda2 instead of /dev/sda2.

Tested in QEMU/KVM with VirtIO, VirtualBox and VMware.

diff --git a/config/Config-images.in b/config/Config-images.in
index 39e51e4..f44ec73 100644
--- a/config/Config-images.in
+++ b/config/Config-images.in
@@ -267,8 +267,6 @@ menu "Target Images"
 	config TARGET_ROOTFS_PARTNAME
 		string "Root partition on target device"
 		depends on OLPC_BOOTSCRIPT_IMAGES || GRUB_IMAGES
-		default "/dev/xvda2" if TARGET_x86_xen_domu
-		default "/dev/sda2" if ! TARGET_x86_xen_domu
 		help
 		  The root partition on the final device.  If you don't know,
 		  you probably want the default (/dev/sda2).
diff --git a/target/linux/x86/base-files/lib/preinit/79_move_config b/target/linux/x86/base-files/lib/preinit/79_move_config
index 0bffbab..1d4873d 100644
--- a/target/linux/x86/base-files/lib/preinit/79_move_config
+++ b/target/linux/x86/base-files/lib/preinit/79_move_config
@@ -1,21 +1,14 @@
 #!/bin/sh
-# Copyright (C) 2012 OpenWrt.org
+# Copyright (C) 2012-2015 OpenWrt.org
 
 move_config() {
-	local rootfsdev
-	local rootfstype
-	
-	rootfstype="$(awk 'BEGIN { RS=" "; FS="="; } ($1 == "rootfstype") { print $2 }' < /proc/cmdline)"
-	case "$rootfstype" in
-		squashfs|jffs2)
-			rootfsdev="$(awk 'BEGIN { RS=" "; FS="="; } ($1 == "block2mtd.block2mtd") { print substr($2,1,index($2, ",")-1) }' < /proc/cmdline)";;
-		ext4)
-			rootfsdev="$(awk 'BEGIN { RS=" "; FS="="; } ($1 == "root") { print $2 }' < /proc/cmdline)";;
-	esac
+	. /lib/upgrade/platform.sh
 
-	mount -t ext4 -o rw,noatime "${rootfsdev%[0-9]}1" /mnt
-	mv -f /mnt/sysupgrade.tgz /
-	umount /mnt
+	if platform_export_bootpart; then
+		mount -t ext4 -o rw,noatime "$BOOTPART" /mnt
+		mv -f /mnt/sysupgrade.tgz /
+		umount /mnt
+	fi
 }
 
 boot_hook_add preinit_mount_root move_config
diff --git a/target/linux/x86/base-files/lib/upgrade/platform.sh b/target/linux/x86/base-files/lib/upgrade/platform.sh
index a2dd20a..73ab5ef 100644
--- a/target/linux/x86/base-files/lib/upgrade/platform.sh
+++ b/target/linux/x86/base-files/lib/upgrade/platform.sh
@@ -1,16 +1,38 @@
-x86_get_rootfs() {
-	local rootfsdev
-	local rootfstype
-	
-	rootfstype="$(awk 'BEGIN { RS=" "; FS="="; } ($1 == "rootfstype") { print $2 }' < /proc/cmdline)"
-	case "$rootfstype" in
-		squashfs|jffs2)
-			rootfsdev="$(awk 'BEGIN { RS=" "; FS="="; } ($1 == "block2mtd.block2mtd") { print substr($2,1,index($2, ",")-1) }' < /proc/cmdline)";;
-		ext4)
-			rootfsdev="$(awk 'BEGIN { RS=" "; FS="="; } ($1 == "root") { print $2 }' < /proc/cmdline)";;
-	esac
-		
-	echo "$rootfstype:$rootfsdev"
+platform_export_bootpart() {
+	local cmdline uuid disk
+
+	if read cmdline < /proc/cmdline; then
+		case "$cmdline" in
+			*block2mtd=*)
+				disk="${cmdline##*block2mtd=}"
+				disk="${disk%%,*}"
+			;;
+			*root=*)
+				disk="${cmdline##*root=}"
+				disk="${disk%% *}"
+			;;
+		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 /dev/[hsv]d[a-z]; do
+					set -- $(dd if=$disk bs=1 skip=440 count=4 2>/dev/null | hexdump -v -e '4/1 "%02x "')
+					if [ "$4$3$2$1" = "$uuid" ]; then
+						export BOOTPART="${disk}1"
+						return 0
+					fi
+				done
+			;;
+			/dev/*)
+				export BOOTPART="${disk%[0-9]}1"
+				return 0
+			;;
+		esac
+	fi
+
+	return 1
 }
 
 platform_check_image() {
@@ -26,19 +48,19 @@ platform_check_image() {
 }
 
 platform_copy_config() {
-	local rootfs="$(x86_get_rootfs)"
-	local rootfsdev="${rootfs##*:}"
-	
-	mount -t ext4 -o rw,noatime "${rootfsdev%[0-9]}1" /mnt
-	cp -af "$CONF_TAR" /mnt/
-	umount /mnt
+	if [ -b "$BOOTPART" ]; then
+		mount -t ext4 -o rw,noatime "$BOOTPART" /mnt
+		cp -af "$CONF_TAR" /mnt/
+		umount /mnt
+	fi
 }
 
 platform_do_upgrade() {
-	local rootfs="$(x86_get_rootfs)"
-	local rootfsdev="${rootfs##*:}"
+	platform_export_bootpart
 
-	sync
-	[ -b ${rootfsdev%[0-9]} ] && get_image "$@" | dd of=${rootfsdev%[0-9]} bs=4096 conv=fsync
-	sleep 1
+	if [ -b "${BOOTPART%[0-9]}" ]; then
+		sync
+		get_image "$@" | dd of="${BOOTPART%[0-9]}" bs=4096 conv=fsync
+		sleep 1
+	fi
 }
diff --git a/target/linux/x86/image/Makefile b/target/linux/x86/image/Makefile
index 5983718..1f91b9f 100644
--- a/target/linux/x86/image/Makefile
+++ b/target/linux/x86/image/Makefile
@@ -40,7 +40,9 @@ ifneq ($(GRUB_TERMINALS),)
   GRUB_TERMINAL_CONFIG := terminal_input $(GRUB_TERMINALS); terminal_output $(GRUB_TERMINALS)
 endif
 
+SIGNATURE:=$(shell dd if=/dev/urandom bs=4 count=1 2>/dev/null | hexdump -v -e '"%08x"')
 ROOTPART:=$(call qstrip,$(CONFIG_TARGET_ROOTFS_PARTNAME))
+ROOTPART:=$(if $(ROOTPART),$(ROOTPART),PARTUUID=$(SIGNATURE)-02)
 
 GRUB_TIMEOUT:=$(call qstrip,$(CONFIG_GRUB_TIMEOUT))
 
@@ -82,7 +84,7 @@ ifneq ($(CONFIG_GRUB_IMAGES),)
 		-e 's#@CMDLINE@#$(strip $(call Image/cmdline/$(1)) $(BOOTOPTS) $(GRUB_CONSOLE_CMDLINE))#g' \
 		-e 's#@TIMEOUT@#$(GRUB_TIMEOUT)#g' \
 		./grub.cfg > $(KDIR)/root.grub/boot/grub/grub.cfg
-	PADDING="$(CONFIG_TARGET_IMAGES_PAD)" PATH="$(TARGET_PATH)" ./gen_image_generic.sh \
+	PADDING="$(CONFIG_TARGET_IMAGES_PAD)" SIGNATURE="$(SIGNATURE)" PATH="$(TARGET_PATH)" ./gen_image_generic.sh \
 		$(BIN_DIR)/$(IMG_PREFIX)-combined-$(1).img \
 		$(CONFIG_TARGET_KERNEL_PARTSIZE) $(KDIR)/root.grub \
 		$(CONFIG_TARGET_ROOTFS_PARTSIZE) $(KDIR)/root.$(1) \
diff --git a/target/linux/x86/image/gen_image_generic.sh b/target/linux/x86/image/gen_image_generic.sh
index 9d11efb..3fb31f6 100755
--- a/target/linux/x86/image/gen_image_generic.sh
+++ b/target/linux/x86/image/gen_image_generic.sh
@@ -20,7 +20,7 @@ sect=63
 cyl=$(( ($KERNELSIZE + $ROOTFSSIZE) * 1024 * 1024 / ($head * $sect * 512)))
 
 # create partition table
-set `ptgen -o "$OUTPUT" -h $head -s $sect -p ${KERNELSIZE}m -p ${ROOTFSSIZE}m ${ALIGN:+-l $ALIGN}`
+set `ptgen -o "$OUTPUT" -h $head -s $sect -p ${KERNELSIZE}m -p ${ROOTFSSIZE}m ${ALIGN:+-l $ALIGN} ${SIGNATURE:+-S 0x$SIGNATURE}`
 
 KERNELOFFSET="$(($1 / 512))"
 KERNELSIZE="$(($2 / 512))"