#!/bin/bash

# Copyright (C) 2016 Paul Kocialkowski <contact@paulk.fr>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

KEYBLOCK="keyblock"
VBPRIVK="vbprivk"
VBPUBK="vbpubk"

usage() {
	printf "$executable [action] [firmware image path]\n" >&2

	printf "\nActions:\n" >&2
	printf "  sign - Sign firmware image\n" >&2
	printf "  verify - Verify firmware image\n" >&2

	printf "\nEnvironment variables:\n" >&2
	printf "  VBOOT_KEYS_PATH - Path to the vboot keys\n" >&2
	printf "  VBOOT_TOOLS_PATH - Path to vboot tools\n" >&2
}

sign() {
	local firmware_image_path=$1

	futility sign --signprivate="$VBOOT_KEYS_PATH/firmware_data_key.$VBPRIVK" --keyblock "$VBOOT_KEYS_PATH/firmware.$KEYBLOCK" --kernelkey "$VBOOT_KEYS_PATH/kernel_subkey.$VBPUBK" --infile "$firmware_image_path"
	futility gbb_utility -s --recoverykey="$VBOOT_KEYS_PATH/recovery_key.$VBPUBK" --rootkey="$VBOOT_KEYS_PATH/root_key.$VBPUBK" "$firmware_image_path" "$firmware_image_path"

	printf "\nSigned firmwares image $firmware_image_path\n"
}

verify() {
	local firmware_image_path=$1

	futility verify -k "$VBOOT_KEYS_PATH/root_key.$VBPUBK" "$firmware_image_path" || ( printf "\nBad firmware image signature!\n" >&2 && return 1 )

	printf "\nVerified firmware image $firmware_image_path\n"
}

requirements() {
	local requirement
	local requirement_path

	for requirement in "$@"
	do
		requirement_path=$( which "$requirement" || true )

		if [ -z "$requirement_path" ]
		then
			printf "Missing requirement: $requirement\n" >&2
			exit 1
		fi
	done
}

setup() {
	root=$( realpath "$( dirname "$0" )" )
	executable=$( basename "$0" )

	if ! [ -z "$VBOOT_TOOLS_PATH" ]
	then
		PATH="$PATH:$VBOOT_TOOLS_PATH"
	fi

	if [ -z "$VBOOT_KEYS_PATH" ]
	then
		if ! [ -z "$VBOOT_TOOLS_PATH" ] && [ -d "$VBOOT_TOOLS_PATH/devkeys" ]
		then
			VBOOT_KEYS_PATH="$VBOOT_TOOLS_PATH/devkeys"
		else
			VBOOT_KEYS_PATH="/usr/share/vboot/devkeys"
		fi
	fi
}

cros_firmware_prepare() {
	local action=$1
	local firmware_image_path=$2

	set -e

	setup "$@"

	if [ -z "$action" ] || [ -z "$firmware_image_path" ]
	then
		usage
		exit 1
	fi

	case $action in
		"sign")
			if ! [ -f "$firmware_image_path" ]
			then
				usage
				exit 1
			fi

			requirements "futility"
			sign "$firmware_image_path"
			;;
		"verify")
			requirements "futility"
			verify "$firmware_image_path"
			;;
		*)
			usage
			exit 1
			;;
	esac
}

cros_firmware_prepare "$@"