creates zombie processes with AnyEvent / EV

[ufobat]

Hello,

I tried to create a simple script that uses Net::OpenSSH in cobination with AnyEvent. My AnyEvent installation uses EV, since it is the first choice of AnyEvent on the EvenLoop impementation.

Unfortunately I had to see that my script wasn't working but creating zombie childs. It seems that there is a race condition on the signal handlers. Singalhandling is global to the process, and EV does the signal handling in libev.

In the source of Net::OpenSSH you try to respect if $SIG{CHLD} is already set (probably by any other eventloop that uses $SIG{CHLD}). Maybe you could fix my issue with allowing EV to handle the singals in C-Land via an constructor option to Net::OpenSSH?

#!/usr/bin/env perl;

use common::sense;
use AnyEvent;
use AnyEvent::Util;
use Net::OpenSSH;

### If you use this $loop, you will create a ssh zombie
my $loop = AnyEvent->condvar;

my $ssh = Net::OpenSSH->new(
        "localhost",
        user   => "ssh-test",
        passwd => 'Kon4vl17',
        async  => 1
);

### IF you have the $loop here, everythign is fine
# my $loop = AnyEvent->condvar;

my $w;
$w = AnyEvent->timer( interval => 0.1, after => 0.1, cb => sub {
        if ( $ssh->wait_for_master(1) ) {

                # the connection has been established!
                # remote commands can be run now
                undef $w;
                say "success";
                my @cmd = $ssh->make_remote_command( echo => 'hello!' );
                if (@cmd) {
                        my $out = '';
                        my $cv = AnyEvent::Util::run_cmd( \@cmd, '>' => \$out );
                        $cv->cb(sub {
                                                say "command executed: $out";
                                                undef $cv;
                                                $loop->send;
                                        });
                }
                else {
                        # something went wrong!
                }
        }
        elsif ( $ssh->error ) {

                # connection can not be established
                undef $w;
                say "conn failure";
        }
});

$loop->recv;