#!/usr/bin/perl -w

use constant FIFOPATH => "/tmp/fifo-demo";
use POSIX qw(mkfifo);
use Fcntl qw(O_RDONLY);
use Sys::Syslog qw( :DEFAULT setlogsock);

# catch signals to die gracefully
$SIG{'TERM'} = 'handler';
$SIG{'INT'} = 'handler';

# syslog
sub do_syslog {
        my $msg = shift;
        setlogsock('unix');
        openlog($0,'','user');
        syslog('info',"$msg");
        closelog;
}


sub handler {
    my $signal = shift;    # signal-nummer besorgen
    $SIG{'TERM'} = 'handler';   # reinstall sig-handler
    $SIG{'INT'} = 'handler';   # reinstall sig-handler

    &do_syslog ("Signal: SIG$signal caught!");
    unlink(FIFOPATH);
    exit 0;
}

sub do_notification {
        my $string = shift;
        &do_syslog($string);
        # instead of this 'sleep' here should be some intelligent code to
        # do magic stuff with the data we got from uncle fifo.
        sleep 5;
}

########################### MAIN ################################


unlink(FIFOPATH);
mkfifo(FIFOPATH, 0666) or die "can't create FIFO: $!\n";

sysopen(FIFOFD, FIFOPATH, O_RDONLY) or die "can't read: $!\n";

#my $fifostring = "";
#while (1) {
#    if (sysread(FIFOFD, $fromfifo, 1) == 1) {
#       if ($fromfifo eq "\n") {
#               &do_notification($fifostring);
#               $fifostring = "";
#       } else {
#               $fifostring .= $fromfifo;
#       }
#    }
#}

# easyer reading line-by-line
while (1) {
        while (<FIFOFD>) {
                &do_notification($_);
        }
}

#!/usr/bin/perl -w
# fifo-client.pl -- Sendet Auftraege in eine FIFO hinein.

use strict;
use Data::Dumper;

my $fifo = "/tmp/fifo-demo";
my $string = shift;


#sysopen(FIFOFD, FIFOPATH, O_WRONLY) or die "can't write: $!\n";
open (FIFOFD, ">$fifo") or die "could not open fifo: $!\n";
print FIFOFD "$string\n";
close (FIFOFD);

while(1) { ... }

close (FIFOFD);