#!/bin/busybox ash
# vim:ft=sh

# Init must have pid 1 otherwise switch_root won't work.
if [ $$ -ne 1 ]; then
	echo "init must have pid 1!"
	exit 1
fi

# Predefice colors
C_NO="\e[0m"
C_GRAY="\e[1;30m"
C_RED="\e[1;31m"
C_GREEN="\e[1;32m"
C_YELLOW="\e[1;33m"

PATH="$PATH:/usr/sbin:/usr/bin:/sbin:/bin"

# disable kernel message from terminal and clear screen
echo 0 > /proc/sys/kernel/printk
clear

# TODO print some welcome ascii art :-)

# Function called if we fail. Argument is error message.
fail() {
	echo -e "${C_RED}$@${C_NO}"
	echo -e "${C_YELLOW}Dropping to interactive shell${C_NO}"
	busybox --install -s
	while true; do
		echo -e "${C_GRAY}Mount root to /mnt/root and exit shell to switch root.${C_NO}"
		# Note: this is hack to enable job control
		setsid sh -c 'exec sh </dev/tty1 >/dev/tty1 2>&1'
		echo
		exec switch_root /mnt/root /sbin/init || echo -e "${C_RED}Root switch failed!${C_NO}"
	done
}

# Preliminary mounts
busybox mount -t proc none /proc || fail "/proc mount failed!"
busybox mount -t sysfs none /sys || fail "/sys mount failed!"
busybox mount -t devtmpfs none /dev || fail "/dev mount failed!"

# Now open and mount root
uuid=""
rootflags=""
recovery=false

for opt in $(cat /proc/cmdline); do
	case "$opt" in
		rootuuid=*)
			uuid="${opt:9}"
			;;
		rootflags=*)
			rootflags=${opt:10}
			;;
		recovery)
			recovery=true
			;;
		BOOT_IMAGE=*|initrd=*|fbcon=*)
			# Ignore those
			;;
		*)
			echo -e "${C_YELLOW}Unknown kernel argument: $opt${C_NO}"
			;;
	esac
done

$recovery && fail "Requested recovery."

[ -z "$uuid" ] && fail "Missing rootuuid argument!"

echo -ne "${C_GRAY}Waiting for root ($uuid)..."
CNT=10
while [ $CNT -gt 0 ] && ! blkid | grep -q "UUID=\"$uuid\""; do
	CNT=$((CNT - 1))
	sleep 1
	echo -n " $CNT"
done
echo -e "${C_NO}"

root="$(blkid | awk -v uuid="UUID=\"$uuid\"" '$2 == uuid { gsub(/:$/,"",$1); print $1 }')"
[ -e "$root" ] || fail "Root not located!"

echo -e "${C_GREEN}Unlocking root...${C_NO}"
if command -v initramfs_password >/dev/null; then
	initramfs_password | cryptsetup open --key-file=- "$root" encroot
else
	cryptsetup open "$root" encroot
fi || fail "Unlocking root failed! /proc/cmdline=$(cat /proc/cmdline)"

echo -e "${C_GREEN}Mounting root...${C_NO}"
mount -t btrfs -o "$rootflags" /dev/mapper/encroot /mnt/root \
	|| fail "Mounting root failed! /proc/cmdline=$(cat /proc/cmdline)"


echo -e "${C_GREEN}Switching to real root${C_NO}"

# First clean up. The init process will remount proc, sys and dev later on
busybox umount /dev /sys /proc || fail "Unmouns failed!"

# Now do switch
exec switch_root /mnt/root /sbin/init || fail "Root switch failed!"