#!/usr/bin/perl
#
#	Laptop SETI Manager - 0.0.5
#	
#	A silly little script to save battery power on laptops running GNU/Linux.
#	It starts/stops the SETI@home client based on which power 
#	supply the laptop is running off of.  When AC power is detected, 
#	setiathome is started, and when AC power is removed (ie. on 
#	battery) setiathome is killed.  There are probably better ways
#	to do this, but it works. :-)
#
#	Laptop SETI Manager is written by Scott Holmes (norgasm@hotmail.com)
#	This software is provided to the public domain without
#	any warranty expressed or implied.  Use at your own risk.
#	Feel free to drop me a line if this was useful to you.
#
#	Usage: 
#		Add 'nohup [path]/lapsetiman & > /dev/null' to your rc.local
#	file to have setiman started on bootup, and forget it's there...
#	(I hope)....
#

my $path = '/root/seti';	#Path to SETI@home files
my $interval = 30;		#Time in seconds between polls


use strict;

my $apm;
my @apm;
my $junk1;
my $junk2;

while (1) {

	####################################### 
	# Find the pid of the SETI@home client
	# by  parsing the output of ps

	my $pid = '';
	open (PS, 'ps aux | ') || die "Cannot run ps!\n";
	while (<PS>) {
		if (/setiathome/i) {
			s/ +/ /;
			($junk1, $pid, $junk2) = split / /;
		}
	}
	close (PS);
	

	#######################################
	# Look in /proc/apm to determine if
	# we're on AC power or battery

	open (APM, '/proc/apm') || die "Cannot open $!: You need to have \/proc filesystem with apm!\n";
	my $apm = <APM>;
	close (APM) || die "Cannot close $!\n";
	my @apm = split / /, $apm;

	#######################################
	# Take appropriate action (either start
	# or stop the SETI@home client).

	if ($apm[3] eq '0x01') {
	#	print "Power is ON\n";
		if ( !$pid ) {
			chdir $path || die "$! does not exist\n";
			system './setiathome &';
		}
	} else  {
		if ($pid) { kill 9, $pid }
	#	print "Power is OFF\n";
	}	

	sleep $interval;
}