#!/usr/bin/perl -w
use strict;
use IO::Socket::INET;

my $PORT = $ARGV[0];
my $IP_ADDRESS = $ARGV[1];
if ((!defined $PORT) || (!defined $IP_ADDRESS)){
print "Please provide the IP-Adress or Port no!!\ne.g. Perl TCP_Server.pl <port no> <IP-Address>\nPerl TCP_Server.pl 7777 127.0.0.1\n";
exit 0;
}
my $Receiving_Port = $PORT;

# flush after every write
$| = 1;
my ( $socket,      $received_data );
my ( $peeraddress, $peerport );
$socket = new IO::Socket::INET (
	LocalHost => $IP_ADDRESS,
	LocalPort => $Receiving_Port,
	Proto => 'tcp',
	Listen => 5,
	Reuse => 1
) or die "ERROR in Socket Creation : $!\n";
$socket->listen();
$socket->autoflush(1);
print "TCP Server Started\n";
# Stay in endless loop to wait and look for tcp commands to be executed.
my $addr;
while (1) {
	$addr = $socket->accept();
	print "$addr\n";
	$peeraddress = $addr->peerhost();
	$peerport = $addr->peerport() ;
	
	my $pid = fork();
	# ignore signal CHILD in linux to prevent Zombie Process.
	if ( $^O !~ m/mswin32/i )
	{
		$SIG{CHLD} = 'IGNORE';
	}
	if ( $pid == 0 )
	{
		my $exitCode;
		while (<$addr>) {
			# Read all messages from client 
			# Print received message
			$received_data = $_;
			# Execute RunCommand for running the command and sending its response back.
			$exitCode = RunCommand( $received_data, $peeraddress, $peerport );
		}
		exit $exitCode;
		close $addr;
	}
}

# Close socket when Command is received.
$socket->close();


sub RunCommand
{
	my $Command_To_Send = shift;
	my $send_ip         = shift;
	my $peerport 		= shift;
	# file handler which will have response values.
	my $fileHandler;
	print "Executing: '$Command_To_Send'\n";
	print "Output on: '$send_ip:$peerport'\n";
	if ( $Command_To_Send =~ m/Check Connectivity/i )
	{
		#sleep 20;
		## Send Response back to Client, that tcp_server is now connected.
		print $addr "Connected to TCP socket server\n";
		return 0;
	}
	
	if ( $Command_To_Send =~ m/\x03|\x1A/i )
	{
		return 0;
	}
	# Execute the command by opening a pipe to channel. -| will read STDOUT
	# and assign it to fileHandler.
	my @pid = open( $fileHandler, '-|', "$Command_To_Send 2>&1" );
	if ( $^O !~ m/mswin32/i )
	{

		#Traversing pid array.
		foreach (@pid)
		{
			print "'$Command_To_Send' PID: $_\n";
			print $addr "Process ID = $_\n";
		}
	}
	# if no pid is assigned, means the command was incorrect or error while
	# sending the commmand.
	if ( $#pid == -1 )
	{
		warn "Cannot Open Command !!\n";
		print $addr "'$Command_To_Send' Unable to Start\n";
	}

	# hotlist the filehandler for immediate flushing, no buffering.
	my $ofh = select $fileHandler;
	$| = 1;
	select $ofh;

	print $addr "Sending Command '$Command_To_Send'\n";
	# write response of command to tcp socket which is sent to ATF.
	while (<$fileHandler>)
	{
		print $addr $_;
	}
	print $addr "\n";
	print $addr "normal-exit\n";
	print $addr "done\n";
	
	# Killing if any process has not completed gracefully.
	# Traversing pid array.
	foreach (@pid)
	{
		my $curr_pid = $_;
		if ( $^O !~ m/mswin32/i )
		{
			kill 9, $curr_pid;
		}
	}

	#Closing filehandler.
	close($fileHandler);
	return 0;
}