#!/bin/sh
### BEGIN INIT INFO
# Provides:          rng-tools-debian rng-tools
# Required-Start:    $remote_fs $syslog
# Required-Stop:     $remote_fs $syslog
# Default-Start:     2 3 4 5
# Default-Stop:      0 1 6
# Short-Description: rng-tools (Debian variant)
# Description:       The rng-tools daemon bridges between a hardware
#                    TRNG and the kernel PRNG, verifying input data.
### END INIT INFO

# absolute basics
LC_ALL=C PATH=/sbin:/usr/sbin:/bin:/usr/bin
export LC_ALL PATH
unset LANGUAGE

# exit cleanly if disabled or not installed
test -x /usr/sbin/rngd || exit 0

# Debian/LSB init script foobar
DESC='Hardware RNG entropy gatherer daemon'
NAME=rngd
. /lib/init/vars.sh
test -t 0 && VERBOSE=yes
. /lib/lsb/init-functions

# read options
HRNGDEVICE=
HRNGSELECT=
RNGDOPTIONS=
test -r /etc/default/rng-tools-debian && . /etc/default/rng-tools-debian

finddevice() {
	if test -n "$HRNGDEVICE" && test -c "$HRNGDEVICE"; then
		# use it unseen
		return 0
	fi
	# list of devices to try/auto-detect
	for x in hwrng hw_random hwrandom intel_rng i810_rng; do
		for y in /dev /dev/misc; do
			test -c "$y/$x" || continue
			if timeout -k 1s 5s \
			    dd if="$y/$x" bs=1 count=1 >/dev/null 2>&1; then
				HRNGDEVICE=$y/$x
				return 0
			fi
			logger -t rng-tools-debian \
			    "found $y/$x but could not use it"
		done
	done
	return 1
}

# prepare for actions
case $1 in
(start|restart|try-restart|force-reload)
	test -z "$HRNGSELECT" || printf '%s' "$HRNGSELECT" \
	    >/sys/devices/virtual/misc/hw_random/rng_current
	if ! finddevice; then
		logger -t rng-tools-debian \
		    "not starting: no hardware RNG device found"
		log_daemon_msg "Configuring $DESC"
		log_progress_msg "no hardware RNG device found!"
		log_end_msg 1
		test -e /run/rngd.installing || exit 0
		# during postinst run, inform user more
		cat <<-\EOF

			!!! no hardware RNG device found !!!
			rng-tools-debian will SILENTLY not start the daemon!

			To fix this, edit /etc/default/rng-tools-debian to
			set options suitable for your hardware random device;
			possibly load some kernel module first, ideally from
			initramfs (add to /etc/initramfs-tools/modules), so
			it is available early enough during boot.

		EOF
		exit 0
	fi
	;;
(stop|status)
	;;
(reload|*)
	# not supported
	echo >&2 "Usage: $0 {start|stop|restart|try-restart|force-reload|status}"
	exit 3
	;;
esac

# take action
rv=0
case $1 in
(status)
	status_of_proc -p /var/run/rngd.pid /usr/sbin/rngd rngd
	exit $?
	;;
(start)
	test x"$VERBOSE" = x"no" || log_daemon_msg "Starting $DESC"
	if start-stop-daemon --start --quiet \
	    --pidfile /var/run/rngd.pid \
	    --startas /usr/sbin/rngd --name rngd \
	    --exec /usr/sbin/rngd --test; then
		test x"$VERBOSE" = x"no" || log_progress_msg "rngd"
		start-stop-daemon --start --quiet \
		    --pidfile /var/run/rngd.pid \
		    --startas /usr/sbin/rngd --name rngd \
		    --exec /usr/sbin/rngd -- -r $HRNGDEVICE $RNGDOPTIONS
		rv=$?
	else
		test x"$VERBOSE" = x"no" || \
		    log_progress_msg "rngd already running"
	fi
	;;
(stop)
	test x"$VERBOSE" = x"no" || log_daemon_msg "Stopping $DESC"
	test x"$VERBOSE" = x"no" || log_progress_msg "rngd"
	start-stop-daemon --stop --quiet --retry=10 \
	    --pidfile /var/run/rngd.pid \
	    --name rngd --exec /usr/sbin/rngd
	rc=$?
	if test $rc -gt 1; then
		rv=$rc
	else
		start-stop-daemon --stop --quiet --oknodo \
		    --retry=0/30/KILL/5 --exec /usr/sbin/rngd
		rc=$?
		test $rc -gt 1 && test $rv -lt $rc && rv=$rc
	fi
	rm -f /var/run/rngd.pid
	;;
(restart|force-reload)
	test x"$VERBOSE" = x"no" || log_daemon_msg "Restarting $DESC"
	test x"$VERBOSE" = x"no" || log_progress_msg "rngd"
	start-stop-daemon --stop --quiet --retry=10 \
	    --pidfile /var/run/rngd.pid \
	    --name rngd --exec /usr/sbin/rngd
	if test $? -lt 2; then
		start-stop-daemon --stop --quiet --oknodo \
		    --retry=0/30/KILL/5 --exec /usr/sbin/rngd
	fi
	rm -f /var/run/rngd.pid
	start-stop-daemon --start --quiet \
	    --pidfile /var/run/rngd.pid \
	    --startas /usr/sbin/rngd --name rngd \
	    --exec /usr/sbin/rngd -- -r $HRNGDEVICE $RNGDOPTIONS
	rv=$?
	;;
(try-restart)
	test x"$VERBOSE" = x"no" || log_daemon_msg "Trying to restart $DESC"
	if ! status_of_proc -p /var/run/rngd.pid \
	    /usr/sbin/rngd rngd >/dev/null 2>&1; then
		test x"$VERBOSE" = x"no" || log_progress_msg "is not running."
		test x"$VERBOSE" = x"no" || log_end_msg 1
		exit 0
	fi
	test x"$VERBOSE" = x"no" || log_progress_msg "rngd"
	start-stop-daemon --stop --quiet --retry=10 \
	    --pidfile /var/run/rngd.pid \
	    --name rngd --exec /usr/sbin/rngd
	if test $? -lt 2; then
		start-stop-daemon --stop --quiet --oknodo \
		    --retry=0/30/KILL/5 --exec /usr/sbin/rngd
	fi
	rm -f /var/run/rngd.pid
	start-stop-daemon --start --quiet \
	    --pidfile /var/run/rngd.pid \
	    --startas /usr/sbin/rngd --name rngd \
	    --exec /usr/sbin/rngd -- -r $HRNGDEVICE $RNGDOPTIONS
	rv=$?
	;;
esac
test x"$VERBOSE" = x"no" || log_end_msg $rv
exit $rv