State-taint analysis for detecting resource bugs

To ensure that a program uses its resources in an appropriate manner is vital for program correctness. A number of solutions have been proposed to check that programs meet such a property on resource usage. But many of them are sophisticated to use for resource bug detection in practice and do not take into account the expectation that a resource should be used once it is opened or required. This open-but-not-used problem can cause resource starvation in some cases, for example, smartphones or other mobile devices where resources are not only scarce but also energy-hungry, hence inappropriate resource usage can not only cause the system to run out of resources but also lead to much shorter battery life between battery recharge. That is the so-call energy leak problem. In this paper, we propose a static analysis called state-taint analysis to detect resource bugs. Taking the open-but-not-used problem into account, we specify the appropriate usage of resources in terms of resource protocols. We then propose a taint-like analysis which employs resource protocols to guide resource bug detection. As an extension and an application, we enrich the protocols with the inappropriate behaviours that may cause energy leaks, and use the refined protocols to guide the analysis for energy leak detection. We implement the analysis as a prototype tool called statedroid. Using this tool, we conduct experiments on several real Android applications and test datasets from Relda and GreenDroid. The experimental results show that our tool is precise, helpful and suitable in practice, and can detect more energy leak patterns.