Killing external commands when user aborts page

[taa_]

Hi Guys !

I need to execute some external unix commands from a PHP page .. and capture the output to a variable.
Furthermore, I want to display the command output "real-time" - so that my users can see what the command does.

I've come up with this function :

function RunCmd ($cmd="", $arg="") {

    // Reset Result buffer
    $res = "";

    // Escape Shell stuff ..
    $cmd = escapeShellCmd($cmd);
    $arg = escapeShellCmd($arg);

    // Do more sanity checks here .....

    ob_implicit_flush(1);
    echo '<pre>';

    $fp = popen ( $cmd . " " . $arg . " 2>&1", "r");
    while ($line = fgets ($fp, 4096) )  {
            echo htmlentities($line);
            $res .= $line;
            }
    pclose ($fp);

    echo '</pre>';
    ob_implicit_flush(0);
    return ($res);

}

Works like expected, but when a user aborts the PHP script, the external command continues. The BIG problem is, that the user cannot access any pages on the web-server while the external command is still running. It kind of locks the session.

How can I avoid this ?

Thanks for your input...

/Tom