Have a monitoring app written in perl that forks off a bunch of sub processes. Sometimes, these sub processes hang on bad nodes and won't die off. Been trying to use sig alrm to kill them but I just can't seem to get this right. Forking still confuses me a bit, so guessing I'm just not quite getting it here. Would appreciate any input.

Here is some sample code. Every fork should get killed off due to the sleep but isn't.
A bit of the code here was taken from examples I found, some of it probably isn't necessary.

#!/bin/perl
for ($i=0; $i<=10; $i++) {
        wait_for_a_kid() if keys %pid_to_node > 3;
        $pid = fork;
        if ($pid) {
                ## parent does...
                $pid_to_node{$pid} = $i;
        }
        else {
                print "$i $$\n";
                local $SIG {ALRM} = sub {
                kill -15, $$ or die "kill: $!";
                print "\tKilled PID $$\n"}; # Just SIGTERM
                eval {
                        ## child does...
                        setpgrp(0,0);
                        exit !&Test;
                        alarm 1;
                        waitpid $pid => 0;
                };
        }
}
## final reap:
1 while wait_for_a_kid();

sub wait_for_a_kid {
        my $pid = wait;
        return 0 if $pid < 0;
        my $node = delete $pid_to_node{$pid} or warn("Why did I see $p
+id ($?)\n"), next;
}

sub Test {
        sleep 10;
}

[download]
OUTPUT:

0 1668
1 1669
2 1670
3 1671
Why did I see 1668 (0)
5 1811
6 1812
7 1813
8 1814
9 1920
10 1921

In reply to Killing Forks by Earindil

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