#!/bin/sh

# Created by jiaqiang.ye@lnxall.com
# Lnxall initialization for System
# 2023/06/27

# IMPORTANT: DO NOT CREATE RUNNING PROCESSES WHICH
# CONTINUES TO RUN AFTER THE SCRIPT'S TERMINATION.
# PLEASE DO EXIT SCRIPT WITH ZERO STATUS

# System initialization script for EM-1000 aarch64 board

create_sysinfo() {
	local retv=0
	local sysdir='/tmp/sysinfo'

	# create /tmp/sysinfo directory
	mkdir -p -m 0755 ${sysdir} ; retv=$?
	[ $retv -ne 0 ] && return 1

	# write board_name file
	if [ ! -f "${sysdir}/board_name" ] ; then
		echo 'WLOSANY_EM1000' > "${sysdir}/board_name"
		retv=$?
		chmod 644 "${sysdir}/board_name"
		[ $retv -ne 0 ] && return 2
	fi

	# write model file
	if [ ! -f "${sysdir}/model" ] ; then
		echo 'WLOSANY_EM1000' > "${sysdir}/model"
		retv=$?
		chmod 644 "${sysdir}/model"
	fi
	return $retv
}

create_dir() {
	local dirp="$1"
	if [ -d "${dirp}" ] ; then
		# already created, just return
		return 0
	fi

	[ -e "${dirp}" ] && rm -rf "${dirp}"
	mkdir -p "${dirp}"
	return $?
}

wait_file() {
	local file="$1"
	local maxcnt="$2"
	local count=0
	while [ ${count} -le ${maxcnt} ] ; do
		if [ -e "${file}" ] ; then
			break
		fi
		echo "Waiting for '${file}': ${count}..."
		sleep 1 ; count=$((count + 1))
	done
	return 0
}

symlink_file() {
	local source="$1"
	local target="$2"

	wait_file "${source}" 20 # wait until file show-up

	local dolink=1
	if [ -e "${target}" ] ; then
		local real="$(readlink -f ${target})"
		[ "${real}" = "${source}" ] && dolink=0
	fi

	if [ ${dolink} -ne 0 ] ; then
		rm -v -rf "${target}"
		ln -s -v -f "${source}" "${target}"
		return $?
	fi
	return 0
}

# setup tty serial device for EM-1000 arm64 device
setup_ttyserial() {
	# /dev/ttyRS232-1 -> ttyS0
	# /dev/ttyRS232-2 -> ttyS1
	# ---------------------------
	# /dev/ttyRS485-1 -> ttySPRU4
	# /dev/ttyRS485-2 -> ttySPRU5
	# /dev/ttyRS485-3 -> ttyS4
	# /dev/ttyRS485-4 -> ttySPRU3
	# /dev/ttyRS485-5 -> ttySPRU1
	# /dev/ttyRS485-6 -> ttySPRU2
	# /dev/ttyRS485-7 -> ttyS3
	# /dev/ttyRS485-8 -> ttySPRU0

	symlink_file '/dev/ttySPRU4' '/dev/ttylnx1' || return 1
	symlink_file '/dev/ttySPRU5' '/dev/ttylnx2' || return 2
	symlink_file '/dev/ttyS3'    '/dev/ttylnx3' || return 3
	symlink_file '/dev/ttySPRU3' '/dev/ttylnx4' || return 4
	symlink_file '/dev/ttySPRU1' '/dev/ttylnx5' || return 5
	symlink_file '/dev/ttySPRU2' '/dev/ttylnx6' || return 6
	symlink_file '/dev/ttyS4'    '/dev/ttylnx7' || return 7
	symlink_file '/dev/ttySPRU0' '/dev/ttylnx8' || return 8
	return 0
}

# in order for br-lan to work on EM1000:
# 1, /proc/sys/net/ipv4/ip_forward should be 1;
# 2, NAT should be enabled with iptables.
brlan_setup() {
	if [ "$(cat /proc/sys/net/ipv4/ip_forward)" != "1" ] ; then
		echo 1 > /proc/sys/net/ipv4/ip_forward
	fi

	local masq="$(iptables -t nat -L POSTROUTING | grep -e MASQUERADE | wc -l)"
	[ -z "${masq}" ] && masq=0
	if [ ${masq} -le 3 ] ; then
		# does this have any other side effects?
		iptables -t nat -A POSTROUTING -o net1     -j MASQUERADE
		iptables -t nat -A POSTROUTING -o net2     -j MASQUERADE
		iptables -t nat -A POSTROUTING -o eth0     -j MASQUERADE # eth0 might be a 4G network device
		iptables -t nat -A POSTROUTING -o usb0     -j MASQUERADE
		iptables -t nat -A POSTROUTING -o modem0   -j MASQUERADE
	fi
	return 0
}

mount_ssd() {
	local MNTDIR='/mnt/ssd'
	if [ ! -d "${MNTDIR}" ] ; then
		rm -rf "${MNTDIR}" # in case it is a file
		mkdir -p "${MNTDIR}"
	fi

	# check again for mount directory
	if [ ! -d "${MNTDIR}" ] ; then
		echo "Error, ssd mount directory not found: '${MNTDIR}'" 1>&2
		return 1
	fi

	# check if already mounted
	if mountpoint -q "${MNTDIR}" ; then
		echo "INFO: SSD already mounted to '${MNTDIR}'."
		return 0
	fi

	local BDEV=/dev/nvme0
	if [ ! -c "${BDEV}" ] ; then
		echo "INFO: No SSD character device found, skip mount."
		return 0
	fi

	# to prevent any suspicious, umount it first:
	umount "${MNTDIR}" >/dev/null 2>/dev/null

	BDEV=/dev/nvme0n1 # block partition
	mount -orw -t ext4 ${BDEV} "${MNTDIR}"
	if [ $? -ne 0 ] ; then
		echo "Error, failed to mount SSD. you might need to format it first." 1>&2
		return 2
	fi
	return 0
}

mainfunc() {
	local rval=0

	brlan_setup
	create_dir '/var/run/lnxall' ; rval=$?
	if [ ${rval} -ne 0 ] ; then
		echo "Error, failed to create /var/run/lnxall directory!" 1>&2
		return 1
	fi

	create_sysinfo ; rval=$?
	if [ ${rval} -ne 0 ] ; then
		echo "Error, function has failed: create_info: ${rval}" 1>&2
		return 2
	fi

	setup_ttyserial ; retv=$?
	[ ${rval} -ne 0 ] && return 3

	# power-on 4G module, refer to: https://manual.zlg.cn/web/?from_wecom=1#/228/9127
	gpioset '0' '25=0'

	# mount Solid State Drive if it exists
	mount_ssd # error should be ignored
	return 0
}

mainfunc ; exit $?