#! /bin/sh
### BEGIN INIT INFO
# Provides:          urandom
# Required-Start:    $local_fs
# Required-Stop:     $local_fs
# Default-Start:     S
# Default-Stop:      0 6
# Short-Description: Save and restore random seed between reboots.
# Description        This script saves the random seed between reboots.
#                    It is called from the boot, halt and reboot scripts.
### END INIT INFO
#
# Version:	@(#)urandom  2.85-14  31-Mar-2004  miquels@cistron.nl
#

[ -c /dev/urandom ] || exit 0

[ -z "$VERBOSE" ] && VERBOSE=yes
[ -f /etc/default/rcS ] && . /etc/default/rcS

. /lib/lsb/init-functions

POOLSIZE=512
if [ -f /proc/sys/kernel/random/poolsize ]
then
	POOLSIZE="`cat /proc/sys/kernel/random/poolsize`"
fi
SAVEDFILE=/var/lib/urandom/random-seed

case "$1" in
	start|"")
		[ "$VERBOSE" != no ] && log_action_begin_msg "Initializing random number generator"

		# Load and then save $POOLSIZE bytes,
		# which is the size of the entropy pool
		if [ -f "$SAVEDFILE" ]
		then
			# Handle locally increased pool size
			SAVEDSIZE=`find $SAVEDFILE -printf "%s"`
			if [ "$SAVEDSIZE" -gt "$POOLSIZE" ]
			then
				[ -w /proc/sys/kernel/random/poolsize ] && echo $POOLSIZE > /proc/sys/kernel/random/poolsize
				POOLSIZE=$SAVEDSIZE
			fi
			cat "$SAVEDFILE" >/dev/urandom
		fi
		rm -f $SAVEDFILE
		umask 077
		dd if=/dev/urandom of=$SAVEDFILE bs=$POOLSIZE count=1 >/dev/null 2>&1
		ES=$?
		umask 022
		[ "$VERBOSE" != no ] && log_action_end_msg $ES
		;;
	stop)
		# Carry a random seed from shut-down to start-up;
		# see documentation in linux/drivers/char/random.c
		[ "$VERBOSE" != no ] && log_action_begin_msg "Saving random seed"
		umask 077
		dd if=/dev/urandom of=$SAVEDFILE bs=$POOLSIZE count=1 >/dev/null 2>&1
		ES=$?
		[ "$VERBOSE" != no ] && log_action_end_msg $ES
		;;
        restart|reload|force-reload)
        	echo "Error: argument '$1' not supported" >&2
		exit 3
		;;
	*)
		echo "Usage: urandom start|stop" >&2
		exit 3
		;;
esac

exit 0
