#!/usr/bin/perl -w
use strict;
use warnings;

my $port = 7777;
my $host;

use POSIX;
use IO::Socket;

my $sock = new IO::Socket::INET(
    Reuse => 1,
    Listen => 5,
    Proto => 'tcp',
    LocalAddr => "127.0.0.1:$port",
) || die "no socket :$!";

POSIX::setsid;

my($new_sock, $c_addr, $buf);
open( my $log, '>>', 'log.txt') || die "Couldn't open log.txt: $!";
while( ($new_sock, $c_addr) = $sock->accept() )
{
    my ($client_port, $c_ip) = sockaddr_in($c_addr);
    my $client_ipnum         = inet_ntoa($c_ip);
    my $client_host          = gethostbyaddr($c_ip, AF_INET);
    print "got a connection from: $client_host [$client_ipnum] \n";

    # New process handles data till client disconnects.
    if( not fork ) {

        while (defined ($buf = <$new_sock>))
        {
            print "$$ $buf";
            print $log "$$ $buf";
        }
        warn "$$ exiting: $client_host [$client_ipnum]\n";
        exit 0;
    }
}

END { kill 'TERM', -$$; }