Article ID Journal Published Year Pages File Type
461262 Journal of Systems and Software 2011 15 Pages PDF
Abstract

We consider software written for networked, wireless sensor nodes, and specialize software verification techniques for standard C programs in order to locate programming errors in sensor applications before the software's deployment on motes. Ensuring the reliability of sensor applications is challenging: low-level, interrupt-driven code runs without memory protection in dynamic environments. The difficulties lie with (i) being able to automatically extract standard C models out of the particular flavours of embedded C used in sensor programming solutions, and (ii) decreasing the resulting program's state space to a degree that allows practical verification times.We contribute a platform-dependent, OS-independent software verification tool for OS-wide programs written in MSP430 embedded C with asynchronous hardware interrupts. Our tool automatically translates the program into standard C by modelling the MCU's memory map and direct memory access. To emulate the existence of hardware interrupts, calls to hardware interrupt handlers are added, and their occurrence is minimized with a double strategy: a partial-order reduction technique, and a supplementary reachability check to reduce overapproximation. This decreases the program's state space, while preserving program semantics. Safety specifications are written as C assertions embedded in the code. The resulting sequential program is then passed to CBMC, a bounded software verifier for sequential ANSI C. Besides standard errors (e.g., out-of-bounds arrays, null-pointer dereferences), this tool chain is able to verify application-specific assertions, including low-level assertions upon the state of the registers and peripherals.Verification for wireless sensor network applications is an emerging field of research; thus, as a final note, we survey current research on the topic.

► We specialize software verification for use with wireless sensor software. ► The target software is OS-wide embedded C for TelosB platforms. ► State-space reduction is done with partial-order reduction and reachability checks. ► No new errors are found; the detection of a known bug is demonstrated.

Related Topics
Physical Sciences and Engineering Computer Science Computer Networks and Communications
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