[Perl-unix-users] Threads

[wjnorth]

Please reference the following code snippet:

if ($curoctet == $ipcount) { #we've reached the first one
                        @count = split ',', $scantargs;
                        @targs = reverse(@count);
                        foreach (@targs) {
                                $targ = $_;
                                #next if ($targ eq "");
                                $scancmd = qq!nmap -sS -P0 -p 1-65535 -T 5 -O -oN ./$targ.txt $targ!;
                                #$foo = scanning();
                                $hostcheck = hostup();
                                if ($hostcheck == 1) {
                                        $thread = threads->new(\&scanning); # Spawn the thread
                                        $thread->detach;
                                } else {
                                        print "$targ is down\n";
                                        next;
                                }
                        }
                        ($sc = $curip) =~ s/(.*\.)(.*$)/$2/; #set new start count variable
                        print "Encountered maxscans, need to wait till the PID's complete\n";
                        $ipcount += $maxscans; #add another maxscans to the ips
                        $scantargs = "";
                        `sleep 2`;
}

sub hostup {
        $isup = "";
        $timeout = 1;
        $p = Net::Ping->new();
        if ($p->ping($targ, $timeout)) {
                $isup = 1;
        } else {
                $isup = 0;
        }
        return $isup;
}
sub scanning {
        print "$scancmd\n";
}

When I run this I get the desired results, however, I have 3 questions:

1. How do I create a parent thread and join child threads to that parent in order to control them?
2. How do I check the status of a thread to make sure it has finished?
3. Why am I getting the following errors?

Attempt to free non-existent shared string 'detach' during global destruction.
Attempt to free non-existent shared string 'new' during global destruction.
Scalars leaked: -2
Unbalanced string table refcount: (1) for "new" during global destruction.
Unbalanced string table refcount: (1) for "detach" during global destruction.
Scalars leaked: 2

Am I exiting the script without properly closing the thread? And if so, how do I close it?

-Wes