#!/bin/sh
. /etc/config
. /etc/functions

add=""
remove=""
config="*.cfg"
unique="n"
hashed="n"
while getopts "b:d:p:a:r:c:uh" arg; do
	case $arg in
		b) bootdir="$OPTARG" ;;
		d) paramsdev="$OPTARG" ;;
		p) paramsdir="$OPTARG" ;;
		a) add="$OPTARG" ;;
		r) remove="$OPTARG" ;;
		c) config="$OPTARG" ;;
		u) unique="y" ;;
		h) hashed="y" ;;
	esac
done

if [ -z "$bootdir" ]; then
	die "Usage: $0 -b /boot/"
fi

if [ -z "$paramsdev" ]; then
	paramsdev="$bootdir"
fi

if [ -z "$paramsdir" ]; then
	paramsdir="$bootdir"
fi

first_menu="y"
get_menu_option() {
	num_options=`cat $TMP_MENU_FILE | wc -l`
	if [ $num_options -eq 0 ]; then
		recovery "No boot options"
	fi

	if [ $num_options -eq 1 -a $first_menu = "y" ]; then
		option_index=1
	else
		echo "+++ Select your boot option:"
		n=0
		while read option
		do
			parse_option
			n=`expr $n + 1`
			echo "$n. $name [$kernel]"
		done < $TMP_MENU_FILE

		read \
			-p "Choose the boot option [1-$n, a to abort]: " \
			option_index

		if [ "$option_index" = "a" ]; then
			recovery "Aborting boot attempt"
		fi
	fi
	first_menu="n"

	option=`head -n $option_index $TMP_MENU_FILE | tail -1`
	parse_option
}

confirm_menu_option() {
	echo "+++ Please confirm the boot details for $name:"
	echo $option

	read \
		-n 1 \
		-p "Confirm selection by pressing 'y', make default with 'd': " \
		option_confirm
	echo
}

parse_option() {
	name=`echo $option | cut -d\| -f1`
	kernel=`echo $option | cut -d\| -f3`
}

scan_options() {
	echo "+++ Scanning for unsigned boot options"
	option_file="/tmp/kexec_options.txt"
	if [ -r $option_file ]; then rm $option_file; fi
	for i in `find $bootdir -name "$config"`; do
		kexec-parse-boot $i >> $option_file
	done
	if [ ! -r $option_file ]; then
		recovery "Failed to parse any boot options"
	fi
	if [ "$unique" = 'y' ]; then
		sort $option_file | uniq > $TMP_MENU_FILE
	else
		cp $option_file $TMP_MENU_FILE
	fi
}

default_select() {
	# Attempt boot with expected parameters

	# Check that entry matches that which is expected from menu
	default_index=`basename "$TMP_DEFAULT_FILE" | cut -d. -f 2`

	# Check to see if entries have changed - useful for detecting grub update
	expectedoption=`cat $TMP_DEFAULT_FILE`
	option=`head -n $default_index $TMP_MENU_FILE | tail -1`
	if [ "$option" != "$expectedoption" ]; then
		recovery "Boot entry has changed: expected $expectedoption, found $option"
	fi
	parse_option

	# Enforce that default option hashes are valid
	echo "+++ Checking verified default boot hash file "
	# Check the hashes of all the files
	if cd $bootdir && sha256sum -c "$TMP_DEFAULT_HASH_FILE" ; then
		echo "+++ Verified default boot hashes "
	else
		recovery "$TMP_DEFAULT_HASH_FILE: default boot hash mismatch"
	fi

	echo "+++ Executing default boot for $name:"
	kexec-boot -b "$bootdir" -e "$option" -a "$add" -r "$remove"
	recovery "Something failed"
}

user_select() {
	# No default expected boot parameters, ask user

	# Optionally enforce device file hashes
	if [ -r $TMP_HASH_FILE ]; then
		echo "+++ Checking verified boot hash file "
		# Check the hashes of all the files
		if cd $bootdir && sha256sum -c "$TMP_HASH_FILE" ; then
			echo "+++ Verified boot hashes "
			hashed='y'
		else
			recovery "$TMP_HASH_FILE: boot hash mismatch"
		fi
	fi

	option_confirm=""
	while [ "$option_confirm" != "y" -a "$option_confirm" != "d" ]
	do
		get_menu_option
		confirm_menu_option

		if [ "$option_confirm" = 'd' ]; then
			if ! kexec-save-default -b "$bootdir" -d "$paramsdev" -p "$paramsdir" -e "$option" -i "$option_index"; then
				echo "!!!!!! Failed to save defaults"
			else
				echo "+++ Saved defaults to device"
				sleep 2
			fi
		fi
	done

	if [ "$option_confirm" = "d" ]; then
		# reload settings to reflect new default
		continue
	fi

	if [ "$CONFIG_BOOT_REQ_HASH" = "y" -a "$hashed" = "n" ]; then
		recovery "!!!!!! Missing required boot hashes"
	fi

	kexec-boot -b "$bootdir" -e "$option" -a "$add" -r "$remove"
	recovery "Something failed"
}

while true; do
	kexec-check-config $paramsdir
	TMP_MENU_FILE="/tmp/kexec/kexec_menu.txt"
	TMP_HASH_FILE="/tmp/kexec/kexec_hashes.txt"
	TMP_DEFAULT_FILE=`find /tmp/kexec/kexec_default.*.txt 2>/dev/null | head -1`
	TMP_DEFAULT_HASH_FILE="/tmp/kexec/kexec_default_hashes.txt"

	# if no saved options, scan the boot directory and generate
	if [ ! -r $TMP_MENU_FILE ]; then
		scan_options
	fi

	if [ -r "$TMP_DEFAULT_FILE" -a -r "$TMP_DEFAULT_HASH_FILE" ]; then
		default_select
	else
		user_select
	fi

	recovery "Something failed again"
done