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Filename : bootloader-script
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# -*- shell-script -*- vim:ft=sh:
#---------------------------------------------------------------------
# Description: Update kernel/core snap.
# Entry point: mountroot().
#---------------------------------------------------------------------

. /scripts/ubuntu-core-functions

# Save "bootloader" environment in $1
saveenv()
{
	echo "snap_mode=$snap_mode
snap_try_core=$snap_try_core
snap_try_kernel=$snap_try_kernel
snap_core=$snap_core
snap_kernel=$snap_kernel" > "$1".tmp
	mv "$1".tmp "$1"
	sync
}

# Flash kernel snap with name $1 to partition $2
flash_kernel()
{
	local partition="$1"
	local kernel_snap="$2"
	local kernel_mnt="/tmpmnt_kernel"
	mkdir -p "$kernel_mnt"
	mount "${writable_mnt}/system-data/var/lib/snapd/snaps/${kernel_snap}" \
	      "$kernel_mnt"

	cat "${kernel_mnt}/boot.img" > "$partition"
	sync
}

# Modify kernel command line of partition $1 with core $2 and kernel $3
modify_kernel_cmdline()
{
	local cmdline
	local partition="$1"
	local core="$2"
	local kernel="$3"
	cmdline=$(abootimg -i "$partition" | grep cmdline)
	cmdline="${cmdline#\* cmdline = }"
	cmdline=$(echo "$cmdline" \
			     | sed "s/snap_core=[[:alnum:]_.-]*/snap_core=$core/" \
			     | sed "s/snap_kernel=[[:alnum:]_.-]*/snap_kernel=$kernel/")
	abootimg -u "$partition" -c "cmdline=$cmdline"

	sync
}

#---------------------------------------------------------------------
# XXX: Entry point - called by the initramfs "/init" script.
# For it to be called, the line
# "BOOT=bootloader-script"
# must be present in one of the configuration files in /conf/conf.d/
#---------------------------------------------------------------------
mountroot()
{
	pre_mountroot

	log_begin_msg "Running /scripts/local-premount"
	run_scripts /scripts/local-premount
	log_end_msg

	writable_label="writable"
	writable_mnt="/tmpmnt_${writable_label}"
	mkdir -p "$writable_mnt"

	# mount the root fs
	do_root_mounting

	aboot_folder="${writable_mnt}/androidboot"
	aboot_env="${aboot_folder}/androidboot.env"

	# If no environment, this is the first boot
	if [ ! -e "${aboot_folder}/androidboot.env" ]; then
		log_success_msg "This is the first boot"
		reboot recovery
	fi

	# Read configuration options
	. "$aboot_env"

	# Find recovery partition
	recovery_partition=$(findfs PARTLABEL="recovery" 2>/dev/null || :)
	[ -e "$recovery_partition" ] || panic "recovery partition does not exist"

	# Make sure update has not already failed
	if [ "$snap_mode" = "trying" ]; then
		snap_mode=""
		saveenv $aboot_env
		log_failure_msg "mode is still \"trying\"! Reverting..."

		if [ "$snap_try_kernel" != "" ]; then
			log_begin_msg "Re-flashing old kernel"
			flash_kernel "$recovery_partition" "$snap_kernel"
			log_end_msg
		fi

		# Modify kernel command line
		modify_kernel_cmdline "$recovery_partition" "$snap_core" "$snap_kernel"
		log_failure_msg "- booting"
		reboot recovery
	fi

	# Check if we are trying a snap, reboot otherwise
	if [ "$snap_mode" != "try" ]; then
		log_success_msg "no core/kernel updates, booting"
		reboot recovery
	fi

	snap_mode="trying"
	saveenv $aboot_env

	# Force panic if we fail while trying to update
	set -e

	if [ "$snap_try_core" != "" ]; then
		snap_core="$snap_try_core"
	fi

	if [ "$snap_try_kernel" != "" ]; then
		snap_kernel="$snap_try_kernel"

		# Flash newer kernel
		log_begin_msg "flashing new kernel"
		flash_kernel "$recovery_partition" "$snap_kernel"
		log_end_msg
	fi

	# Modify command line
	modify_kernel_cmdline "$recovery_partition" "$snap_core" "$snap_kernel"

	log_success_msg "update finished, booting"

	reboot recovery
}