binblog

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

my $cupsq  = "/var/spool/cups";

my @ledidle  = (1, 0, 0, 0);
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 $jobcount = 0;
        find ( sub { $jobcount++ if ("d" eq substr($_,0,1)) }, $cupsq);
        if ($jobcount > 0){
                my $popped = pop @ledstate;
                unshift @ledstate, $popped;
        }else{
                @ledstate = @ledidle;
        }
        if ($killed){
                @ledstate = @ledidle;
        }
        unless ("@ledstate" eq "@ledsaved"){
                set_led (1, $ledstate[0]);
                set_led (2, $ledstate[1]);
                set_led (3, $ledstate[2]);
                @ledsaved = @ledstate;
        }
        last if $killed;
        usleep 100000;
}

sub set_led{
        my $led     = shift;
        my $state   = shift;
        my $sysfile = "/sys/class/leds/alix:$led/brightness";
        open my $fh_out, ">$sysfile" or die "$sysfile: $!\n";
        print $fh_out "$state\n";
        close $fh_out;
}