# $Id$

SOCKET=~/.ssh/agent

function get_agent_pid() {
  ps waux | grep -- ^$USER\ .\*ssh-agent\ -a\ .\*\ -s | grep -v grep | awk '{ print $2 }' | head -n 1
}

if [ ! -z "$SSH_CLIENT" ]; then
  # Set display if we aren't already forwarding X11
  if [ "$DISPLAY" = "" ]; then
    export DISPLAY="$(echo $SSH_CLIENT | cut -s -d ' ' -f 1):0"
  fi
fi

# Try to hook up with already running ssh-agent.
if [ $UID -gt 0 ]; then
  # Not all OSes support ``ps -wu''.
  RUNNING_AGENT="$(get_agent_pid)"

  # Has the socket gone away?
  if [ ! -z "$RUNNING_AGENT" -a ! -S "$SOCKET" ]; then
    if kill $RUNNING_AGENT; then
      RUNNING_AGENT="$(get_agent_pid)"
    else
      echo >&2 "$SOCKET has gone away but agent is running as PID $RUNNING_AGENT."
    fi
  fi

  if [ -z "$SSH_AGENT_PID" -o ! "$SSH_AGENT_PID" = "$RUNNING_AGENT" ]; then
    export SSH_AGENT_PID="$RUNNING_AGENT"
    if [ "$SSH_AGENT_PID" = "" ]; then
      unset SSH_AGENT_PID
      unset SSH_AUTH_SOCK
      # Start ssh-agent up then.
      rm -f "$SOCKET"
      eval $(/usr/bin/ssh-agent -a "$SOCKET" -s)
      trap "kill $SSH_AGENT_PID" 0
      ssh-add
    else
      export SSH_AUTH_SOCK="$SOCKET"
    fi
  fi
  unset RUNNING_AGENT
fi

unset SOCKET
unset get_agent_pid