PHP脚本不会在Control + C上死亡

Question

I have a PHP script that uses exec to launch some commands in Linux. It's a simple wget that is set to die after five minutes hour. The issue I am facing is if I do Control + c as the script is running it wont die till I kill the actual PID of the wget. I tried using pcntl_signal as well as using exec/system/shell_exec etc. and none of them worked. The code I am using is:

<?PHP
system('/usr/bin/timeout 300 wget -c --tries=0 --read-timeout=200 -O /tmp/ll.mp3  http://15323.live.streamtheworld.com:80/WABCAM_SC');  
?>

Answer 1

First of all, you have to declare the ticks directive to make it work in PHP 4.3.0 and newer (see the manual page for pcntl_signal ).

Then you have to register the signal and the callback function which is called when the signal is received. In your case, you want the signal SIGINT which is generated when CTRL + C pressed.

declare(ticks = 1);

// callback function called when signal is received
function shutdown($signal)
{
    echo 'Interrupted using CTRL + C';

    // you probably don't need this condition, just exit should be enough
    if (($signal === SIGINT)) {
        exit;
    }
}

// register the callback function for the specific signal
// SIGINT in this case is generated when you press CTRL + C
pcntl_signal(SIGINT, 'shutdown');

Answer 2

if I do Control + c as the script is running it wont die

This is because the signal SIGINT generated from the terminal by typing the interrupt key is sent only to the foreground process group for the terminal, and timeout segregates itself and the given command from the foreground process group by executing setpgid (0, 0) .
Now, since the SIGINT is not sent to the timeout command, a foreground process would have to handle the signal and thereupon kill the timeout command. As we learn from the failure of an other answer, PHP is not well suited for such signal handling, but we can use a little wrapper script (let's call it timeout.sh ) for this:

time=$1; shift
timeout $time "$@"&
trap "kill $!" INT
wait $!

---

<?PHP
system('timeout.sh 300 wget -c --tries=0 --read-timeout=200 -O /tmp/ll.mp3 …');  
?>