Safe system-level concurrency on resource-constrained nodes

Abstract

Despite the continuous research to facilitate WSNs development, most safety analysis and mitigation efforts in concurrency are still left to developers, who must manage synchronization and shared memory explicitly. In this paper, we present a system language that ensures safe concurrency by handling threats at compile time, rather than at runtime. Based on the synchronous programming model, our design allows for a simple reasoning about concurrency that enables compile-time analysis resulting in deterministic and memory-safe programs. As a trade-off, our design imposes limitations on the language expressiveness, such as doing computationally-intensive operations and meeting hard realtime responsiveness. To show that the achieved expressiveness and responsiveness is sufficient for a wide range of WSN applications, we implement widespread network protocols and the CC2420 radio driver. The implementations show a reduction in source code size, with a penalty of memory increase below 10% in comparison to nesC. Overall, we ensure safety properties for programs relying on high-level control abstractions that also lead to concise and readable code.

A Synchronous Virtual Machine for Multimedia Presentations

“…Esterel is a control-oriented imperative language, while Lustre and Signal are data-oriented declarative languages-the former is a functional language and the latter is an equational language. As other examples of synchronous languages, one can cite the imperative languages Reactive-C [63], Gentzen [64], Quartz [65], and Céu [66]; the declarative languages Lucid [67] and Lucid Synchrone [68]; and the graphical languages Statecharts [69], Argos [70], and SyncCharts [71].…”

Scripting Customized Components for Wireless Sensor Networks

“…Céu-T implements a variation of Céu programming language (Sant'Anna et al, 2013). This variation, on one hand, excludes some of Céu's characteristics and, on the other hand, includes some language extensions.…”

“…Trails in Céu are guided by reactions to the environments. Furthermore, the extra support for parallelism provides precise information about the program control flow to the Céu compiler, enabling a number of static safety guarantees, such as race-free shared-memory (Sant'Anna et al, 2013).…”

“…To ensure that scripts are always reactive to incoming events, the synchronous model relies on the guarantee that a reaction always executes in bounded time. The Céu compiler statically verifies that programs contain only bounded loops (i.e., loops that contain an await statement in every possible execution path) (Sant'Anna et al, 2013). Even though Céu supports multiple lines of execution, accesses to shared memory are safe.…”

“…Even though Céu supports multiple lines of execution, accesses to shared memory are safe. Because programs can react to only one component-triggered event at a time, the Céu compiler also performs a flow analysis to detect concurrent accesses (Sant'Anna et al, 2013): if two accesses to a variable can occur in reactions to the same event and are in parallel trails, then the compiler issues an error message.…”