file_get_contents - failed to open stream. permission denied

running file_get_contents function in PHP. But if *PUBLIC authority to the
IFS file is *NONE I get a permission denied warning and the function
returns FALSE.

How to know which user profile a PHP script is running as?

Is there a way a PHP script can elevate its authority? Maybe, use the
QSYSETP API to change the user profile of the PHP server job ?

set_error_handler("warning_handler", E_WARNING);
$text = file_get_contents( $fromIfsPath ) ;
restore_error_handler();

// -------------------- warning_handler ---------------------
function warning_handler($errno, $errstr)
{
global $fromIfsPath ;

if ( strpos($errstr, 'Permission denied') != FALSE )
{
echo "Permission denied.\n" ;
echo 'file:' . $fromIfsPath . "\n" ;
}
else
{
error_log( 'warning. errno:' . $errno . ' text:' . $errstr ) ;
echo 'warning. errno:' . $errno . ' text:' . $errstr ;
}
}

thanks,