Environment is not passed to process opened by proc_open - php

Question

I have a problem passing environment variables to processes that i opened with proc_open.
I found the following example on http://us2.php.net/manual/en/function.proc-open.php
<?php
$descriptorspec = array(
0 => array("pipe", "r"), // stdin is a pipe that the child will read from
1 => array("pipe", "w"), // stdout is a pipe that the child will write to
2 => array("file", "/tmp/error-output.txt", "a") // stderr is a file to write to
);
$cwd = '/tmp';
$env = array('some_option' => 'aeiou');
$process = proc_open('php', $descriptorspec, $pipes, $cwd, $env);
if (is_resource($process)) {
// $pipes now looks like this:
// 0 => writeable handle connected to child stdin
// 1 => readable handle connected to child stdout
// Any error output will be appended to /tmp/error-output.txt
fwrite($pipes[0], '<?php print_r($_ENV); ?>');
fclose($pipes[0]);
echo stream_get_contents($pipes[1]);
fclose($pipes[1]);
// It is important that you close any pipes before calling
// proc_close in order to avoid a deadlock
$return_value = proc_close($process);
echo "command returned $return_value\n";
}
?>
The example should echo the env array like the documentation say. But on my machine (PHP 5.4.6-1ubuntu1.4 (cli)) the echoed array is empty. Are there some Suhosin or php.ini restrictions that ban env var passing to processes? I have no idea.

Answer 1

If $_ENV is empty, you should have a look at your variables_order ini setting and ensure that the value contains the E
However, you can use $_SERVER instead:
fwrite($pipes[0], '<?php print_r($_SERVER); ?>');
It will contain environment variables too and should be enabled at 99.999% of servers (I guess)

Answer 2

Set
variables_order = "EGPCS"
in your php.ini