Forked CHILD process won't die. ( SOCKETS )

jburfield

OK...I've been killing myself trying to get this to work properly and it just won't. So I'm hoping someone on this board with more experience with sockets and/or forked processes can help me out a bit.

I've got a 'server' process written in php that starts and waits for connections. As connections come in it forks to handle them.

This works fine.

However, when someone disconnects, the PID for the forked process will not die. It just becomes DEFUNCT. I'm using pcntl_waitpid() and it still isn't working correctly.

If someone can point me in a proper direction I would REALLY appreciate it.

Here's the code:

#!/usr/local/bin/php -q
<?php
error_reporting (E_ALL);

/* Allow the script to hang around waiting for connections. */
set_time_limit (0);

/* Turn on implicit output flushing so we see what we're getting
 * as it comes in. */
ob_implicit_flush ();

$address = 'xx.xx.xx.xx'; /* taken out for posting purposes */
$port = XXXX; /* TAKEN OUT FOR POSTING PURPOSES */

$sock = socket_create (AF_INET, SOCK_STREAM, 0);

$ret = socket_bind ($sock, $address, $port);

$ret = socket_listen ($sock, 5);


function sig_handler()
	{
	/* THIS IS SET TO SPIT OUT OUTPUT IN ORDER TO DEBUG IT */
	$pid = pcntl_waitpid(-1, $status, WNOHANG);
	if($pid > 0)
		{
		print("PID $pid exited.\n");
		}
	else
		{
		die("PID $pid DID NOT EXIT!!!!!!!!\n");
		}
	return;
	}

pcntl_signal(SIGCHLD, "sig_handler");

while (true)
	{
	if($connfd = socket_accept($sock))
		{
		if(($child_pid = pcntl_fork()) == 0)
			{
			socket_close($sock);

		$welcome_msg = "200 - connection ready\n";

		socket_write($connfd, $welcome_msg, strlen($welcome_msg));
		while(true)
			{
			$buf = socket_read($connfd, 2048);
			$buf = trim($buf);
			if($buf == "exit")
				{
				/* GET THE PID FOR THIS CHILD PROCESS */
				$pid = posix_getpid();

				$bye_msg = "Bye!\n\n";

				socket_write($connfd, $bye_msg, strlen($bye_msg));

				print("killing pid: $pid....\n"); /* DEBUG */
				posix_kill($pid, SIGCHLD); /* THIS USES THE PCNTL_WAITPID() IN 'sig_handler' */
				break 2;
				}
			else
				{
				$sendto = "YOU TYPED: '$buf'\n";
				socket_write($connfd, $sendto, strlen($sendto));	
				}
			}
		}
	socket_close($connfd);
	}

}
?>

Everyting works, EXCEPT killing off the forked process...

Right now all it is doing is echo'ing back whatever is typed in. To test this I'm just telnetting to the port to connect. Typing 'exit' disconnects.

I took out a lot of debug code to make it more concise for posting...but the big problem is with getting rid of the forked process...

Any help would be GREATLY appreciated.

Thanks.

-- Jason

Phantazm

Here's how I do it....

<?php
  /* VARIABLES WELL BE USING */
  $user	=	"";
  $pass	=	"";
  $logged_in=	false;

  /* CONFIGURATION VARIBLES */

  $listen_addr		=	'xxx.xxx.xxx.xxx';
  $listen_port		=	xxxx;
  $welcome_message	=	"Server Ports";

  /* DATABASE VARIABLES */
  $db_host		= "localhost";			// mySQL Host System
  $db_user		= "-----";			// mySQL Login Name
  $db_passwd		= "-------";			// mySQL Login Password
  $db_name		= "----------";			// mySQL Database Name

  /* PHP OPTIONS */
  ignore_user_abort(true);
  error_reporting (E_ALL);				// Error Reporting Maximum
  set_time_limit (120);					// Timeout after this amount of Seconds
  ob_implicit_flush ();					// Don't Buffer Output To Browsers

  mysql_connect("$db_host","$db_user","$db_passwd") or die("Fatal Error: Unable to connect to mySQL!");
  mysql_select_db("$db_name") or die("Fatal Error: Unable to open \"$dbname\" database!");

  /* FOR THE REAL SERVER, SET THE FOLLOWING VALUES TO ZERO! */
  set_time_limit(30);
  // error_reporting(0);


  function logit($this)
  {
    $query = "INSERT INTO log (HitIP) VALUES ('$this')";
    $result = mysql_query($query) or die("Fatal Error: mySQL Query Failed");
  }  

  /************************************* SHOW ERROR AND DIE *************************************/
  function myerror_d()
  {
    echo '[error]: ' . socket_strerror(socket_last_error()) . "\n";
    die();
  }

  /************************************* SEND ONE SOCKET DATA *************************************/
  function send_single($sock, $message)
  {
    socket_write($sock, "$message\r\n");
  }

  /************************************* SEND ALL SOCKETS DATA *************************************/
  function send_all($message, $state = STATE_ACTIVE)
  {
    global $s_clients, $cdata;
    foreach ($s_clients as $sock)
    {
      if ($cdata[$sock]['state'] == $state || $state == 0)
      {
        send_single($sock, $message);
      }
    }
  }

  /************************************* SOCKET SHIT HERE *************************************/
  /* ASSIGN LISTENING SOCKET */
  if (!($s_listen = socket_create(AF_INET, SOCK_STREAM, 0))) myerror_d();

  /* REUSE SOCKET */
  if (!socket_setopt($s_listen, SOL_SOCKET, SO_REUSEADDR, 1)) myerror_d();

  /* SET SOCKET TO NON-BLOCKING */
  if (!socket_set_nonblock($s_listen)) myerror_d();

  /* BIND SOCKET TO ADDRESS:PORT */
  if (!socket_bind($s_listen, $listen_addr, $listen_port)) myerror_d();

  /* LISTEN */
  if (!socket_listen($s_listen)) myerror_d();

  /* set initial vars and loop until $abort is set to true */
  $s_clients = Array();
  $abort = false;

  while (!$abort)
  {
    $set = array_merge($s_listen, $s_clients);
    if (socket_select($set, $set_w = NULL, $set_e = NULL, 1, 0) > 0)
    {
      /* LOOP THROUGH ALL THE SOCKETS */
      foreach ($set as $sock)
      {
        /* LISTENING SOCKET HAS A CONNECTION -- DEAL WITH IT */
        if ($sock == $s_listen)
        {
          if (!($this = socket_accept($s_listen))) myerror();
          else
          {
            /* ACCEPT NEW CONNECTION */
            $s_clients[$this] = $this;
            socket_getpeername($this, $addr);
            $cdata[$this]['addr']  = $addr;
            $cdata[$this]['buf']   = '';
            logit($addr);
            echo "[connection]: $addr\n";
            send_single($this, $welcome_message.");
          }
        }
        else
        {
          /* SOCKET IN LOOP HAS INCOMMING DATA */
          if (($read = socket_read($sock, 1024)) === false || $read == '')
          {
            if ($read != '') myerror();
            else
            unset($s_clients[$sock]);
            unset($cdata[$sock]);
          }
          else
          {
            /* only want data with a newline */
            if (strchr($read, "\n") === false)
            {
              $cdata[$sock]['buf'] .= $read;
            }
            else
            {
	      $data = $read;
              if ($cdata[$sock]['buf'] != '')
              {
                $data = $cdata[$sock]['buf'] . $data;
                $cdata[$sock]['buf'] = "";
              }
              $data = trim(strtolower($data));
              if (strstr($data,"****"))
              {
                die("\nReceived authorized shutdown command.  Sockets Closed.");
              }

          elseif (strstr($data,"quit"))
          {
            $x = send_single($sock,"Bye!!!");          
            unset($s_clients[$sock]);
            unset($cdata[$sock]);
            socket_close($sock);
            break;
          }
        }
      }
    }
  }
}
  }
  echo "[end]\n";
?>

If you look at this one.. it doesn't for the process, but rather loops through an array of sockets. This is fine so long as you don't have a TON of simultanious (sp?) connections. If you really "busy" though this would probably be less efficient than a forked process.

jburfield

Yeah...that's the thing, this may end up with quite a few connetions, hence the forking idea.

-- Jason