#!/bin/bash
# Remote TTY monitoring script
# Check local TTY emulation
# If broken for any reason, remount remote TTY with socat
# Remote TTY configured in /etc/remote-tty.conf
#
# Revision history :
# 18/02/2016 - V1.0 - Creation by N. Bernaerts
# 18/09/2017 - V1.1 - Allow tty device access to anybody

# configuration
TTY_CONF="/etc/remote-tty.conf"

# loop thru configuration file
while read LINE; do
  if [ "$LINE" != "" ]
  then
    # get variables
    REMOTE_IP=$(echo "$LINE" | cut -d';' -f1)
    REMOTE_PORT=$(echo "$LINE" | cut -d';' -f2)
    LOCAL_TTY=$(echo "$LINE" | cut -d';' -f3)

    # test if local TTY file is absent as a caracter file
    if [ ! -c "/dev/${LOCAL_TTY}" ]
    then
      # create tty
      socat pty,raw,echo=0,link=/dev/${LOCAL_TTY} tcp:${REMOTE_IP}:${REMOTE_PORT} &
      
      # wait for 1 second
      sleep 1

      # give 666 access right
      chmod 666 "/dev/${LOCAL_TTY}"
    fi
  fi
done < $TTY_CONF