block-extroot: Added md5sum to extroot and underlying root filesystem. This is used to ensure that the extroot is not mounted as the rootfs after a sysupgrade *until the user deals with the extroot).

SVN-Revision: 24230

package/block-extroot/Makefile

@@ -53,6 +53,7 @@ define Package/block-extroot/install
 	$(INSTALL_DATA) ./files/extmount.sh $(1)/lib/functions/
 	$(INSTALL_DIR) $(1)/lib/preinit
 	$(INSTALL_DATA) ./files/50_determine_usb_root $(1)/lib/preinit/
+	$(INSTALL_DATA) ./files/55_determine_extroot_sysupgrade $(1)/lib/preinit/
 	$(INSTALL_DATA) ./files/60_pivot_usb_root $(1)/lib/preinit/
 	$(INSTALL_DIR) $(1)/lib/preinit
 	echo "extroot_settle_time=\"$(CONFIG_EXTROOT_SETTLETIME)\"" >$(1)/lib/preinit/00_extroot.conf

package/block-extroot/files/50_determine_usb_root

@@ -18,6 +18,7 @@ determine_external_root() {
 	if [ "$jffs" = "/tmp/overlay" ] && [ -r "/tmp/overlay/etc/config/fstab" ]; then
 		UCI_CONFIG_DIR="/tmp/overlay/etc/config"
 		ER_IS_SQUASHFS=true
+		ER_OVERLAY_PREFIX="/tmp/overlay"
 	fi
 
 	# For squashfs on firstboot root_device will be tmpfs for the ramoverlay,

package/block-extroot/files/55_determine_extroot_sysupgrade

@@ -0,0 +1,55 @@
+#!/bin/sh
+# Copyright (C) 2010 Daniel Dickinson
+# This is free software, licensed under the GNU General Public License v2.
+# See /LICENSE for more information.
+
+
+check_set_md5sum() {
+	local er_md5sum_file
+	er_md5sum_file="${ER_OVERLAY_PREFIX}/.extroot.md5sum"
+
+	local er_extroot_md5sum
+	if [ -f $md5sum_file ]; then
+		er_extroot_md5sum="$(cat $er_md5sum_file)"
+	fi
+
+	local er_extroot_overlay_md5sum
+	if [ -f "/overlay/etc/extroot.md5sum" ]; then
+		er_extroot_overlay_md5sum="$(cat /overlay/.extroot.md5sum)"
+	fi
+
+	if [ -z "$er_extroot_overlay_md5sum" ]; then
+		cat $er_md5sum_file >/overlay/.extroot.md5sum
+	elif [ "$er_extroot_overlay_md5sum" != "$er_extroot_md5sum" ]; then
+		pi_extroot_mount_success="false"
+		mkdir -p /tmp/overlay-disabled
+		mount --move /overlay /tmp/overlay-disabled
+	fi
+}
+
+set_jffs_md5sum() {
+	# We do this anytime block-extroot exists, even on the first boot with
+	# no extroot defined.
+
+	local er_md5sum_file
+	er_md5sum_file="${ER_OVERLAY_PREFIX}/.extroot.md5sum"
+
+	local er_extroot_md5sum
+	if [ -f $er_md5sum_file ]; then
+		er_extroot_md5sum="$(cat $er_md5sum_file)"
+	fi
+	if [ -z "$er_extroot_md5sum" ]; then
+		dd if=/dev/urandom count=32 bs=1k 2>/dev/null | md5sum | cut -f1 -d\  >$er_md5sum_file
+	fi
+}
+
+determine_extroot_sysupgrade() {
+	check_skip || set_jffs_md5sum
+
+	check_skip || [ "$pi_extroot_mount_success" != "true" ] || {
+		check_set_md5sum
+	}
+}
+
+boot_hook_add preinit_mount_root determine_extroot_sysupgrade
+