#42423 [Opn]: client disconnect not detected by socket_select()

[tinyunderscoregrasshopper at hotmail dot com]

 ID:               42423
 User updated by:  tinyunderscoregrasshopper at hotmail dot com
-Reported By:      tiny_grasshopper at hotmail dot com
+Reported By:      tinyunderscoregrasshopper at hotmail dot com
 Status:           Open
 Bug Type:         Sockets related
 Operating System: Win32 XP SP2
 PHP Version:      5.2.3
 New Comment:

Nevermind this one. The client I used had tendencies to keep de
connection half open.
Sorry for the inconvenience...


Previous Comments:
------------------------------------------------------------------------

[2007-08-25 13:13:11] tinyunderscoregrasshopper at hotmail dot com

Description:
------------
I was working on aan abstraction layer for a multi threaded server. It
was not till very late I noticed the following strange behaviour:

I let a bunch of client connect. Lets say #1, #2 and #3.
When I disconnect them (not gracefuly) in de backward order (#3, #2
then #1) every thing works as it should be; the 'Close' callback
functions are called, and in the right order.

However, when I disconnect them in the same order (#1, #2 then #3) the
callback functions will not be called until the last client is closed.

After further testing I noticed that all client closed will only be
detected by socket_select if the latter clients are closed.

Reproduce code:
---------------
function Error($error, $desc)
{ echo "Error: $error - $desc\n"; }

function Connect($id)
{ echo "#$id connected.\n"; }

function Close($id)
{ echo "#$id closed.\n"; }

function Receive($id, $msg)
{       echo "#$id said: $msg\n"; }

//------------------------------------------------------------------------------

if (($listener = socket_create(AF_INET, SOCK_STREAM, SOL_TCP)) ==
false)
{
        Error("socket_create() failed", socket_strerror($listener));
        exit;
}

socket_set_option($listener, SOL_SOCKET, SO_REUSEADDR, 1); 
socket_set_nonblock($listener);

if (($error = socket_bind($listener, '0.0.0.0', 23)) == false)
{
        Error("socket_bind() failed", socket_strerror($error));
        exit;
}

if (($error = socket_listen($listener, 5)) == false)
{
        Error("socket_listen() failed", socket_strerror($error));
        exit;
}

$sock = array($listener);

//------------------------------------------------------------------------------

for (;;)
{
        $read = $sock;
        socket_select($read, $write = NULL, $except = NULL, NULL);
        
        foreach($read as $socket)
        {
                if ($socket == $listener)
                {
                        if (($client = socket_accept($listener)) == false)
                        {
                                Error("socket_accept() failed", 
socket_strerror($client));
                                continue;
                        } else {
                                $sock[] = $client;
                                $index = intval($client);
                                Connect($index);
                        }
                } else {
                        $bytes = @socket_recv($socket, $input, 512, 0);
                        $index = intval($socket);
                        if ($bytes == 0)
                        {
                                if (($key = array_search($socket, $sock)) !== 
false)
                                        unset($sock[$key]);
                                socket_close($socket);
                                Close($index);
                        } else {
                                Receive($index, $input);
                        }
                } 
        }
}

Expected result:
----------------
#5 connected.
#6 connected.
#7 connected.
#5 closed.
#6 closed.
#7 closed.


Actual result:
--------------
#5 connected.
#6 connected.
#7 connected.
#7 closed.
#5 closed.
#6 closed.


------------------------------------------------------------------------


-- 
Edit this bug report at http://bugs.php.net/?id=42423&edit=1