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Bug #60120 proc_open hangs with stdin/out with 2048+ bytes
Submitted: 2011-10-24 12:10 UTC Modified: 2011-10-26 08:41 UTC
From: pajoye@php.net Assigned: pajoye
Status: Closed Package: Filesystem function related
PHP Version: Irrelevant OS: windows
Private report: No CVE-ID:
 [2011-10-24 12:10 UTC] pajoye@php.net
Description:
------------
The stream used to read data from stdin/out/err hangs if the data passed is 
getting larger than 2048, under certain circumstances. 

Test script:
---------------
error_reporting(E_ALL);

$cmd = 'php -r "fwrite(STDOUT, $in = file_get_contents(\'php://stdin\')); fwrite(STDERR, $in);"';
$descriptors = array(array('pipe', 'r'), array('pipe', 'w'), array('pipe', 'w'));
$stdin = str_repeat('*', 1024 * 16) . '!';
$stdin = str_repeat('*', 2049 );

$options = array_merge(array('suppress_errors' => true, 'binary_pipes' => true, 'bypass_shell' => false));
$process = proc_open($cmd, $descriptors, $pipes, getcwd(), array(), $options);

foreach ($pipes as $pipe) {
    stream_set_blocking($pipe, false);
}
$writePipes = array($pipes[0]);
$stdinLen = strlen($stdin);
$stdinOffset = 0;

unset($pipes[0]);

while ($pipes || $writePipes) {
    $r = $pipes;
    $w = $writePipes;
    $e = null;
    $n = stream_select($r, $w, $e, 60);

    if (false === $n) {
        break;
    } elseif ($n === 0) {
        proc_terminate($process);

    }
    if ($w) {
        $written = fwrite($writePipes[0], (binary)substr($stdin, $stdinOffset), 8192);
        if (false !== $written) {
            $stdinOffset += $written;
        }
        if ($stdinOffset >= $stdinLen) {
            fclose($writePipes[0]);
            $writePipes = null;
        }
    }

    foreach ($r as $pipe) {
        $type = array_search($pipe, $pipes);
        $data = fread($pipe, 8192);
        if (false === $data || feof($pipe)) {
            fclose($pipe);
            unset($pipes[$type]);
        }
    }
}


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History

AllCommentsChangesGit/SVN commitsRelated reports
 [2011-10-24 12:10 UTC] pajoye@php.net
-Assigned To: +Assigned To: pajoye
 [2011-10-24 12:39 UTC] pajoye@php.net
Automatic comment from SVN on behalf of pajoye
Revision: http://svn.php.net/viewvc/?view=revision&revision=318366
Log: - fixed bug #60120, proc_open's streams may hang with stdin/out/err when the data exceeds or is equal to 2048 bytes
 [2011-10-26 06:23 UTC] fabien at symfony dot com
AFAIK, this bug has been fixed here: http://svn.php.net/viewvc?
view=revision&revision=318366
 [2011-10-26 08:41 UTC] pajoye@php.net
-Status: Assigned +Status: Closed
 [2011-10-26 08:41 UTC] pajoye@php.net
This bug has been fixed in SVN.

Snapshots of the sources are packaged every three hours; this change
will be in the next snapshot. You can grab the snapshot at
http://snaps.php.net/.

 For Windows:

http://windows.php.net/snapshots/
 
Thank you for the report, and for helping us make PHP better.

yes (see the commit tab :), I forgot to close it. Thanks for the headup!
 [2012-02-19 14:34 UTC] nicolas dot sauveur at gmail dot com
On my install of php 5.3.9 (windows 7 wamp server 2, apache 2.2.21), the bug has 
only been fixed for 2048 to 4096 bytes. Above that, proc_open still hangs for me.

I use the same test as above, with
$stdin = str_repeat('*', 4097 );
 [2012-02-19 14:48 UTC] nicolas dot sauveur at gmail dot com
seems similar to https://bugs.php.net/bug.php?id=51800
 [2012-04-18 09:48 UTC] laruence@php.net
Automatic comment on behalf of pajoye
Revision: http://git.php.net/?p=php-src.git;a=commit;h=8bd6b9d87af4ec3953bd760c65aea506c70b840b
Log: - fixed bug #60120, proc_open's streams may hang with stdin/out/err when the data exceeds or is equal to 2048 bytes
 [2012-07-24 23:39 UTC] rasmus@php.net
Automatic comment on behalf of pajoye
Revision: http://git.php.net/?p=php-src.git;a=commit;h=8bd6b9d87af4ec3953bd760c65aea506c70b840b
Log: - fixed bug #60120, proc_open's streams may hang with stdin/out/err when the data exceeds or is equal to 2048 bytes
 [2013-03-16 03:16 UTC] hanskrentel at yahoo dot de
In case you don't want to re-open this issue as not fixed, I made a more specific 
report with 4097+ bytes pipes that cause a hang here:

https://bugs.php.net/bug.php?id=64438
 [2013-11-17 09:35 UTC] laruence@php.net
Automatic comment on behalf of pajoye
Revision: http://git.php.net/?p=php-src.git;a=commit;h=8bd6b9d87af4ec3953bd760c65aea506c70b840b
Log: - fixed bug #60120, proc_open's streams may hang with stdin/out/err when the data exceeds or is equal to 2048 bytes
 
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