I'm pretty much a newbie to Perl and am trying to write a script that forks. The child will use Net::RawIP and opens a packet capture descriptor and reads an unspecified number of packets. After 10 seconds, the parent, signals the child to terminate using a KILL signal. The problem is that a <defunct> process for the child remains, at least as far as ps -eaf is concerned. After one minute, the script restarts again. I need to be able to kill the child process after a specified length of time. Any suggestions on the best way to do this?


#!/usr/bin/perl

use warnings;
use strict;

use Net::RawIP; 
use POSIX;

daemonize();

while (1) {

    my $pid = fork();

    print "Process number of script is $$\n";

    unless (defined ($pid)) {
        die "Resources unavailable to fork\n";
    }
    elsif ($pid == 0) {
        my $a = new Net::RawIP; 
        my $p = $a->pcapinit("eth0","udp port 68",1500,30); 
        my $f = ["User-defined message"]; 
        loop $p,10,\&process_pkt,$f; 
    }
    elsif ($pid) {

        for (my $i=0; $i <= 10; $i++ ) {
            sleep 1;
            print "in parent...$i seconds have elapsed...\n";
        }

    print "killing child process $pid";
    kill 9, $pid;    
    sleep 60;
    }

} # end of while loop

sub process_pkt {
    print "packet captured\n";
    my $raw_pkt = $_[2];
    my $raw_data = unpack "H*", $raw_pkt;
    print $raw_data,"\n";
}

sub daemonize {

    my $pid = fork();
    exit if $pid;
    setsid();

}

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In reply to Best way to kill a child process by doylebobs

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