binblog

#!/usr/bin/perl -w
use strict;
use diagnostics;
use POSIX qw(setsid);
use Time::HiRes qw(usleep);
use Data::Dumper;

my $lpstat = "/usr/bin/lpstat";
my $ledbin = "/usr/local/sbin/led";

my @ledidle  = ("on", "off", "off");
my @ledstate = @ledidle;
my @ledsaved;

if (1){
        fork && exit;
        open STDIN,  "/dev/null"  or die "STDIN </dev/null: $!\n";
        open STDOUT, ">/dev/null" or die "STDOUT >/dev/null: $!\n";
        open STDERR, ">/dev/null" or die "STDERR >/dev/null: $!\n";
        setsid();
}

my $killed = 0;
$SIG{TERM} = sub { $killed = 1; };
$SIG{INT}  = sub { $killed = 1; };

while (1){
        my @jobs = `$lpstat -o`;
        my $jobcount = scalar @jobs;
        if ($jobcount > 0){
                my $popped = pop @ledstate;
                unshift @ledstate, $popped;
        }else{
                @ledstate = @ledidle;
        }
        if ($killed){
                @ledstate = @ledidle;
        }
        unless ("@ledstate" eq "@ledsaved"){
                system("$ledbin 1 $ledstate[0]");
                system("$ledbin 2 $ledstate[1]");
                system("$ledbin 3 $ledstate[2]");
                @ledsaved = @ledstate;
        }
        last if $killed;
        usleep 333333;
}