#!/bin/bash

if [ -t /tmp/.gpsd_ctrl_sock ] 
	then
	exit 0
fi

trap 'kill $(jobs -p)' EXIT

rm -f /var/lib/gps/nvd_data
cp /var/lib/gps/nvd_data.bak /var/lib/gps/nvd_data

/usr/sbin/gpsd.orig $@&  GPS_PID=$!
if [ $? -ne 0 ]
	then
	exit $?
fi


echo PID of gpsd $GPS_PID

while :
do
        sleep 30
	(exec 3<>/dev/tcp/localhost/2947;echo -e D >&3; read gpsdata <&3; echo $gpsdata;3<&-;3>&-)
	if [[ $gpsdata == GPSD,D=2* ]]
        then
                cp /var/lib/gps/nvd_data /var/lib/gps/nvd_data.bak
                echo lock
	fi
done
exit 0