class.upload.php is a powerful and mature PHP class to manage uploaded files, and manipulate images in many ways. The script is available under a GPL license.
more info about the class
$handle->file_new_name_body = $name_body; $handle->file_new_name_ext = 'pdf';
Every time you call process(), you reset all parameters, so you can start from scratch to do something else with the file.
As for the log, simply output $handle->log after calling $handle->process().