[Pdns-users] pipe backend logging

[Randall Diffenderfer]

using centos rpm for powerdns, version 3.4.11 (this would seem to be old, but it's what they supply).

using the simple pipe co-process code for perl and trying to figure out where debug log print lines should end up.

i cannot see anything going to the /tmp/pipe.err file, even though it is in /tmp and 777'd.  huh?

==================
#!/usr/bin/perl
# sample PowerDNS Coprocess backend
#

use warnings;
use strict;

$|=1;                                   # no buffering

my $line=<>;
chomp($line);

sub debug_log_a_line {
        `touch /tmp/pipe.err`;
        open( my $errfh, ">> /tmp/pipe.err" ) || die();
        print $errfh "$$ debug_log_a_line call\n";
        foreach ( @_ ) {
                print $errfh $_;
        }
        close $errfh;
        return;
}

unless($line eq "HELO\t1") {
        print "FAIL\n";
        debug_log_a_line( "Received '$line'\n" );
        <>;
        exit;
}

debug_log_a_line( "$$ Starting...\n" );
print "OK\tPipe backend firing up\n";   # print our banner

=================

syslog:

Nov 30 19:23:41 m0095044 pdns[19770]: Backend launched with banner: OK#011Pipe backend firing up


when configured into pds.conf file, i see the banner line show up in syslog messages, but nothing in the pipe.err file.
when i run this as a standalone (without setuid/setguid) stuff prints as expected, and updates the pipe.err file as expected...

this seems exceedingly strange.  what am i overlooking here???

tia!