#! /bin/sh
### BEGIN INIT INFO
# Provides:             gpiod-sysfs-proxy
# Required-Start:       $remote_fs $syslog
# Required-Stop:        $remote_fs $syslog
# Default-Start:        2 3 4 5
# Default-Stop:         1
# Short-Description:    User-space, libgpiod-based compatibility layer for linux GPIO sysfs interface.
### END INIT INFO
#
# -*- coding: utf-8 -*-
# Debian init.d script for gpiod-sysfs-proxy
# Copyright (c) 2024 Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

# set -e

# Source function library.
. /etc/init.d/functions

PROG="/usr/bin/gpiod-sysfs-proxy"
NAME="gpiod-sysfs-proxy"
DESC="/sys/class/gpio compatibility layer"
MOUNTPOINT="@mountpoint@"

test -x $PROG || exit 0

do_start()
{
	echo -n "Starting $DESC: "

	if [ "$MOUNTPOINT" = "/sys/class/gpio" ] && [ ! -e /sys/class/gpio ]; then
		mkdir -p /run/gpio/sys /run/gpio/class/gpio /run/gpio/work
		mount -t sysfs sysfs /run/gpio/sys -o nosuid,nodev,noexec
		# Bail out if overlayfs is not available
		set -e
		mount -t overlay overlay /sys/class \
-o upperdir=/run/gpio/class,lowerdir=/run/gpio/sys/class,workdir=/run/gpio/work,nosuid,nodev,noexec,relatime,ro
		set +e
	else
		mkdir -p $MOUNTPOINT
	fi

	$PROG $MOUNTPOINT -o nonempty -o allow_other -o default_permissions -o entry_timeout=0 -f | logger -i $NAME &
	echo "done"
}

do_stop()
{
	echo -n "Stopping $DESC: "

	umount $MOUNTPOINT

	mountpoint -q /sys/class
	if [ "$?" = "0" ]; then
		umount /sys/class
		umount /run/gpio/sys
		rm -rf /run/gpio
	fi
	echo "done"
}

case "$1" in
	start)
		do_start
	;;
	stop)
		do_stop
	;;
	status)
		status $PROG
		exit $?
	;;
	restart)
		do_stop
		sleep 1
		do_start
	;;
	*)
		echo "Usage: /etc/init.d/$NAME {start|stop|status|restart}" >&2
		exit 1
	;;
esac

exit 0
