Path: utzoo!news-server.csri.toronto.edu!rutgers!sun-barr!newstop!male!anywhere.EBay.Sun.COM!me
From: me@anywhere.EBay.Sun.COM (Wayne Thompson - IR Workstation Support SE)
Newsgroups: comp.lang.perl
Subject: perl and rsh
Message-ID: <5514@male.EBay.Sun.COM>
Date: 11 Mar 91 14:34:17 GMT
Sender: news@male.EBay.Sun.COM
Lines: 46

Has anyone come up with a reliable way to use rsh (remote shell) from perl?

Rsh can hang causing perl to wait for completion. What I've done to work around
the problem is to attach a handler to $SIG{'ALRM'} which kills any rsh commands
attached to the current terminal:

$SIG{'ALRM'} = 'RemoteConnectionHandler';

foreach $client (sort (keys (%cantalkto))) {
    $cmd = "rsh $client cat $PASSWD";
    ($pid = open (REMOTE_CONNECTION, "$cmd 2>&1 |"))
        || die "\n$MYNAME: $cmd: $!\n";

    alarm ($timeout);
    while (<REMOTE_CONNECTION>) {
        alarm (0);
	...
        alarm ($timeout);
    }

    alarm (0);
    close (REMOTE_CONNECTION);
}

sub RemoteConnectionHandler {
    &grepkill (&SIGKILL, $cmd);
    close (REMOTE_CONNECTION);
}

sub grepkill {
    local ($sig, $pat, $pid) = @_;

    $pat =~ s/(\W)/\\$1/g;
    open (PS, "ps $$|"), <PS>;
    open (PS, "ps -t".(split (' ', <PS>))[1]."|"), <PS>;
    kill ($sig, grep (/$pat/, <PS>));
    close (PS);
}

I'm looking for a better way to do this. As this depends on /.rhosts for access,
using chat and the ftp port is not a viable alternative. I also notice that rcmd
is not availble as a syscall.

Any ideas?

Wayne