What do you mean the path of the file? If you mean the path on the users machine, you can't get that. if you mean that path to where it should upload, you should be defining that.
From PHP.net, here are the things you can get about the file
$_FILES['userfile']['name']
The original name of the file on the client machine.
$_FILES['userfile']['type']
The mime type of the file, if the browser provided this information. An example would be "image/gif".
$_FILES['userfile']['size']
The size, in bytes, of the uploaded file.
$_FILES['userfile']['tmp_name']
The temporary filename of the file in which the uploaded file was stored on the server.
$_FILES['userfile']['error']
The error code associated with this file upload. ['error'] was added in PHP 4.2.0
For more checkout this link - http://www.php.net/manual/en/features.file-upload.php
Cgraz