Description:
------------
Accidentally called passthru() on a non-executable file, and it crashed apache.

Reproduce code:
---------------
<?php
    // foo.txt exists, and contains the text "test"
    $result = passthru("foo.txt");
?>

<?php
    // foo does not exist
    $result = passthru("foo");
?>



Expected result:
----------------
A warning or fatal stating the file was not an executable.

Actual result:
--------------
Long pause, apache crash.