Proving the correctness of client/server software

Remote procedure calls (RPCs) lie at the heart of any client/server software. Thus, formal specification and verification of RPC mechanisms is a prerequisite for the verification of any such software. In this paper, we present a mathematical specification of an RPC mechanism and we outline how to prove the correctness of an implementation — say written in C — of this mechanism at the code level. We define a formal model of user processes running concurrently under a simple operating system, which provides inter-process communication and portmapper system calls. A simple theory of non-interference permits us to use conventional sequential program analysis between system calls (within the concurrent model). An RPC mechanism is specified and the correctness proof for server implementations, using this mechanism, is outlined. To the best of our knowledge this is the first treatment of the correctness of an entire RPC mechanism at the code level.