sorry about the terse code snippet....
Basically, I have an SSH tunnel that is controlled by another
process and I want to tell when that ssh tunnel is closed.
(I have both the PID for this SSH tunnel process and the port #
of the local side of the tunnel)
I am checking for closed tunnels 2 ways:
1) if the process is <defunct>
(i realize that the code I wrote doesnt quite illustrate
this 2nd part... sorry)
2) if netstat -an | grep localhost:(port#) shows no
output, then I know that the localhost port is no longer
listening, hence the tunnel is closed.
I guess my question is 2 part:
1) Id like to know if theres a better way to do this
2) Is it really horribly expensive to do this with sys calls?
-----Original Message-----
From: Kipp, James [mailto:[EMAIL PROTECTED]]
Sent: Friday, June 29, 2001 9:52 AM
To: 'Matt Weatherford'; [EMAIL PROTECTED]
Subject: RE: System calls in perl for "ps" and "netstat" - less
expensive way?
Hi Matt
Can you describe a little bit what U are trying to do or include more of
the code. Depending on what U are trying to do, there may be less expensive
alternatives
Thanks
Jim
>
>
>
>
> From PERL, I have been doing some system calls like this:
> (see * lines)
>
>
> * my $procentry=`ps -ef | grep -v grep | grep $self->{pid} `;
> chomp $procentry;
>
> $self->debug(1, "Procentry: [$procentry]");
> if ($procentry =~ /\<defunct\>/ ) {
> $self->debug(1, " <--- closed ssh tunnel. Tunnel proc
> defunct");
> $tunnelok=0;
> }
>
> * my $nstat=`netstat -an | grep '127.0.0.1' `;
> chomp $nstat;
>
> $self->debug(1, "NStat: [$nstat]");
> if (!$nstat) {
> $self->debug(1, " <--- closed ssh tunnel. Netstat
> result empty");
> $tunnelok=0;
> }
>
>
> Is this really computationally expensive?
> (I already know this makes my code not portable)
>
> Im not calling these very often, is there a better way to do this?
>
> thanks,
>
> Matt
>
