sending kill signals from perl CGIs

tachekent has asked for the wisdom of the Perl Monks concerning the following question:

I have a perl process running. When it starts up it writes it's PID into a file. It also has a signal trap.

When I run a file (kill.pl) with this code in it from the command line, it traps the signal:

#!/usr/bin/perl -w
# attempt to kill a pid

use strict;

my $pid;
open (PID, "<signwriter.pid");
while(<PID>){
    $pid = $_;
}
kill 'ALRM', $pid;
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However, if I run the same code as part of a CGI process (called from a web-form), or if I try and run kill.pl from

system "perl ./kill.pl";
[download]

nothing seems to happen.

I don't understand :(

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Re: sending kill signals from perl CGIs by chromatic (Archbishop) on Jan 02, 2003 at 03:17 UTC
You may not have permission to send that signal from the user account as whom the CGI program runs, and you're probably not in the right directory. Add some error checking and see what it tells you.	[reply]
Re: sending kill signals from perl CGIs by mce (Curate) on Jan 02, 2003 at 12:39 UTC
Hi, In unix, only root can kill all processes and the other users can only kill their own. I suggest you should go for a tool called sudo and configure it so that the www (or apache or whatever) can only run this script. Than you need to call `system("sudo kill.pl");` [download] from inside your cgi code. I hope this helps. --------------------------- Dr. Mark Ceulemans Senior Consultant IT Masters, Belgium	[reply] [d/l]
Re: sending kill signals from perl CGIs by fglock (Vicar) on Jan 02, 2003 at 13:15 UTC
I suggest you try starting the process from a CGI. This way you would have the rights to kill it from another CGI!	[reply]
Re: sending kill signals from perl CGIs by tachekent (Acolyte) on Jan 02, 2003 at 03:26 UTC
I thought it might be the perl user. All the files are in the same directory - I sorted that out. Is there a way to override this or set up the CGI user so that it can send that signal?	[reply]