Modifying the behaviour of minix system calls through the redirection of messages

Abstract

Minix 3 is an open-source operating system designed to be highly reliable, flexible, and secure. The kernel is small and user processes, specialized servers and device drivers runs as user-mode isolated processes. Minix is a client/server operating system that uses message transfers as communication primitives between processes. Minix system calls send messages to request for services to the Process Manager Server (PM) or the File System Server (FS), and then waiting for the results. The request messages refer to destination processes with fixed endpoint numbers for each server. This article proposes changes to the Minix kernel that allow the redirection of messages to different servers other than the standard FS or PM, without changes in the source code or binary code of programs.