Bug #52602 [NEW]: fread is blocking even with the use of stream_select

From: Date: Sat, 14 Aug 2010 01:07:42 +0000
Subject: Bug #52602 [NEW]: fread is blocking even with the use of stream_select
Groups: php.bugs 
Request: Send a blank email to php-bugs+get-153418@lists.php.net to get a copy of this message 
From:             
Operating system: Gentoo x86_64
PHP version:      5.2.14
Package:          Sockets related
Bug Type:         Bug
Bug description:fread is blocking even with the use of stream_select

Description:
------------
Using PHP CLI
Gentoo 64 bit box
PHP version 5.2.14
clean compile
Dual AMD Opteron 2212 CPU

Something is blocking in the code, it seems to be fread. I am sure this is
not the expected result.

I greatly simplified the sample I included.

I can just put the socket/stream in non-blocking mode, but I would much
prefer to use the code as I designed it. 

I have considered just using the socket functions in php or just writing
the code in C.

Once in a great while it will resume after about thirty to sixty seconds.
In non-blocking mode I have no issues. This is a php cli script that
connects to another daemon running on the same machine, I am using this php
script to parse data to place in a sql database.

Test script:
---------------
$sock=@fsockopen("localhost","7777",$errno,$errstr,3);
if (!$sock)
{ 
    echo "sock error".$crlf;
}

while(true)
{
    $read=array($sock);
    $write=NULL;
    $except=NULL;
    $status=@stream_select($read,$write,$except,1);
    if ($status===false)
    {
        echo "select error".$crlf;
        exit();
    }
    if ($status>0)
    {
        $data =  @fread($sock,128);
        echo $data;
        $out .= $data;
    }
    
    usleep(10000);
}

Expected result:
----------------
The loop should run for eternity as expected.

Actual result:
--------------
The loop is blocked, I am presuming by fread due to a failure of the
expected behavior of stream_select.

-- 
Edit bug report at http://bugs.php.net/bug.php?id=52602&edit=1
-- 
Try a snapshot (PHP 5.2):            http://bugs.php.net/fix.php?id=52602&r=trysnapshot52
Try a snapshot (PHP 5.3):            http://bugs.php.net/fix.php?id=52602&r=trysnapshot53
Try a snapshot (trunk):              http://bugs.php.net/fix.php?id=52602&r=trysnapshottrunk
Fixed in SVN:                        http://bugs.php.net/fix.php?id=52602&r=fixed
Fixed in SVN and need be documented: http://bugs.php.net/fix.php?id=52602&r=needdocs
Fixed in release:                    http://bugs.php.net/fix.php?id=52602&r=alreadyfixed
Need backtrace:                      http://bugs.php.net/fix.php?id=52602&r=needtrace
Need Reproduce Script:               http://bugs.php.net/fix.php?id=52602&r=needscript
Try newer version:                   http://bugs.php.net/fix.php?id=52602&r=oldversion
Not developer issue:                 http://bugs.php.net/fix.php?id=52602&r=support
Expected behavior:                   http://bugs.php.net/fix.php?id=52602&r=notwrong
Not enough info:                     http://bugs.php.net/fix.php?id=52602&r=notenoughinfo
Submitted twice:                     http://bugs.php.net/fix.php?id=52602&r=submittedtwice
register_globals:                    http://bugs.php.net/fix.php?id=52602&r=globals
PHP 4 support discontinued:          http://bugs.php.net/fix.php?id=52602&r=php4
Daylight Savings:                    http://bugs.php.net/fix.php?id=52602&r=dst
IIS Stability:                       http://bugs.php.net/fix.php?id=52602&r=isapi
Install GNU Sed:                     http://bugs.php.net/fix.php?id=52602&r=gnused
Floating point limitations:          http://bugs.php.net/fix.php?id=52602&r=float
No Zend Extensions:                  http://bugs.php.net/fix.php?id=52602&r=nozend
MySQL Configuration Error:           http://bugs.php.net/fix.php?id=52602&r=mysqlcfg

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