#!/bin/sh
#
# patronus
#
# Dispel ghost logins that suck the joy out of your active terminal session
#
# Copyright (C) 2007 Richard Bullington-McGuire
# Many thanks (and aplologies) to J.K. Rowling
#
# DISCLAIMER
#   This is a parody of J.K. Rowling's Harry Potter novels. 
#   Lawyers: please don't sue this poor house-elf who is only trying to help.
#
# LICENSE
# 
#   This program is free software; you can redistribute it and/or modify
#   it under the terms of the GNU General Public License as published by
#   the Free Software Foundation; either version 3 of the License, or
#   (at your option) any later version.
#
#   This program is distributed in the hope that it will be useful,
#   but WITHOUT ANY WARRANTY; without even the implied warranty of
#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#   GNU General Public License for more details.
#
#   You should have received a copy of the GNU General Public License
#   along with this program.  If not, see <http://www.gnu.org/licenses/>.
#
# Release History:
#
# 1.0 (September 6, 2007)
#  First public release

retval=1
MAGICAL_CREATURES=`mktemp -t patronus.XXXXXXXXXX` && {
	FLOO_NETWORK=`mktemp -t patronus.XXXXXXXXXX` && {
		
		echo "Lumos!"
		echo ""

        	ps x > $MAGICAL_CREATURES

		FLOO_EXITS=`egrep " *$$" $MAGICAL_CREATURES | \
			 awk '{print $2}'`
		awk '!/ PID/{print $2}' < $MAGICAL_CREATURES | \
			sort -u | 
			egrep -v "^\?|$FLOO_EXITS" > $FLOO_NETWORK
		DEMENTORS=`cat $FLOO_NETWORK`
		if [ -z "$DEMENTORS" ] ; then
			echo "No dementors spotted nearby."
			retval=0
		else
			DEMENTOR_KISSES=`grep -f $FLOO_NETWORK < $MAGICAL_CREATURES | \
				awk '{print $1}'`
			DEMENTOR_DESCRIPTION=`ps u $DEMENTOR_KISSES`

			cat << EOT
Traversing floo network at $FLOO_EXITS, dementors spotted at: 
$DEMENTORS

Specialis Revelio!
	
Dementors found: 
$DEMENTOR_DESCRIPTION

EXPECTO PATRONUM!
  
EOT
			kill -HUP $DEMENTOR_KISSES 2>/dev/null
			retval=$?
		fi
		rm -f $FLOO_NETWORK
	}
        rm -f $MAGICAL_CREATURES
}
exit $retval