#!/usr/bin/perl -Tw
#
#

use strict;
use POSIX qw(setsid);

use constant VERSION => 1.10;

$ENV{'PATH'} = '/bin';
delete @ENV{qw(IFS CDPATH ENV BASH_ENV)};

my $PID_FILENAME = "/var/run/one-user-only.pid";
my $ONE_USER_ONLY = "/usr/local/bin/one-user-only.sh";

#
# If this file does exist, then just die accordingly
#
die("$PID_FILENAME exists!!") if ( -f $PID_FILENAME );

#
# If this file does not exist, then just die accordingly
#
die("Cannot find $ONE_USER_ONLY") if ( ! -f $ONE_USER_ONLY );

sub daemonize {

	chdir "/";

	# Close all default file descriptors
	open (STDIN, "</dev/null");
	open (STDOUT, ">/dev/null");
	open (STDERR, ">&STDOUT");
	
	my $pid = fork ();

	# Write the PID to /var/run
	open (FD, ">$PID_FILENAME") or die("Cannot write PID: $!");
	print FD "$$\n";
	close(FD);

	# Detach from the terminal so interrupts cannot occur
	if ($pid < 0) {
		die "fork: $!";
	} elsif ($pid) {
		exit 0;
	}

	# Make session leader
	setsid or die "setsid: $!";
	umask 0;

	foreach (0 .. (POSIX::sysconf (&POSIX::_SC_OPEN_MAX) || 1024)) {
		POSIX::close $_
	}
}

my $continue = 1;
$SIG{TERM} = sub { unlink $PID_FILENAME; $continue = 0; };

&daemonize;

while ($continue) {
	sleep 2;
	system($ONE_USER_ONLY);
}