#!/usr/bin/perl
#
# A simple TCP daemon written in Perl. The script listens for connections on TCP port 7070, 
# and passes text to and from the serial port. This allows multiple local or remote programs 
# to interface with the I/O controller. 
#

use IO::Select;
use IO::File;
use IO::Socket;

sub open_port {
  my($portdevice, $portspeed) = @_;
  system("/bin/stty -F $portdevice speed $portspeed raw > /dev/null 2>&1");
  my $porthandle = new IO::File("+<$portdevice");
  if ($porthandle) {
    $porthandle->autoflush(1);
  }
  return $porthandle;
}

sub command {
  my @ready;
  my $s, $buf;
  my($porthandle, $command) = @_;
  my $read_set = new IO::Select();
  $read_set->add($porthandle);
  
  print $porthandle $command;
  if (@ready = $read_set->can_read(2)) {
    foreach $s (@ready) {
      $buf = <$s>;
      return $buf;
    }
  }
  return 0;
}

$port = open_port("/dev/ttyUSB2", "2400");

$socket = new IO::Socket::INET (LocalHost => '127.0.0.1',
                                LocalPort => '7070',
                                Proto     => 'tcp',
                                Listen    => 16,
                                Reuse     => 1,);
die "Could not create socket: $!\n" unless $socket;

$sock_set = new IO::Select($socket);

while (1) {
  @rh_set = $sock_set->can_read();
  foreach $rh (@rh_set) {
    if ($rh == $socket) {
      $ns = $rh->accept();
      $ns->autoflush(1);
      $sock_set->add($ns);
    }
    else {
      $buf = <$rh>;
      if ($buf) {
        $out = command($port, $buf);
        print $rh $out;
      }
      else {
        $sock_set->remove($rh);
        close($rh);
      }
    }
  }
}