Formal Specification, Verification and Repair of Contiki’s Scheduler

This paper presents an approach for model extraction, formal specification, verification and repair of the scheduler Contiki, which is event-driven lightweight Operating System Internet Things (IoT). We first derive a state machine-based abstraction scheduler’s modes operation along with control flow abstractions most important functions. then use set transformation rules to formally specify all its internal functions in Promela. Additional contributions respect conference version this article include (1) modeling nested function calls Promela using novel technique amenable checking SPIN; (2) protothreads Promela; (3) specifying verifying twelve critical requirements scheduler; (4) detecting new design flaws Contiki’s scheduler, time (to best our knowledge); (5) repairing source code towards fixing detected through verification, as well regression entire (6) experimentally analyzing space costs before after repair. The proposed techniques enhance knowledge regarding components provide reusable methods specification other operating systems used Cyber Physical Systems (CPS) IoT.