Hi Monks,

I'm writing a script that functions a deamon to start and watch over other processes. That is, you can tell the daemon to start some other process (e.g. "ls -lh /var/www/html" or something) and it will fork it off as a child and tell you when it's done. The daemon stays running 24/7. You can also tell it to kill a process that it has started. The way I currently have things set up, the code looks something like this:
my $pid = fork();
if ($pid == 0) {
     #this is the child
     exec("$command_you_requested_me_to_start") or die "Couldn't start
+!\n";
} elseif (!defined($pid)){
     #some sort of error occured...say so and die
     print "ERROR!\n";
     exit;
}

[download]

Then when I try to kill a process that I've started, I use code something like this:
my $attempt = kill('INT', $pid_of_child_process);

[download]

Unfortunately when I do this, the child process I've tried to kill simply becomes a zombie process and don't go away until the daemon script exits. I tried using 'KILL' instead of 'INT' and also played briefly with 'CHLD' and 'SIG_IGN' but got the same results.

Can anyone show me a better way to start/kill these child processes? It would be best if I could use SIGINT for the killing part, since some of the processes will be catching SIGINT and exiting gracefully accordingly....

In reply to Controlling Child Processes by Anonymous Monk

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