Software license is a legal instrument governing the usage or redistribution of copyright-protected software. License analysis is an elaborate undertaking, especially in case of large software consisting of numerous modules under different licenses. This paper describes an automated approach for supporting software license analysis. The approach is implemented in a reverse engineering tool called ASLA. We provide a detailed description of the architecture and features of the tool. The tool is evaluated on the basis of an analysis of 12 OSS (open source software) packages. The results show that licenses for (on average) 89% of the source code files can be identified by using ASLA and that the efficiency of the automated analysis is (on average) 111 files per second. In a further comparison with two other open source license analyzers-OSLC and FOSSology-ASLA shows a competitive performance. The results validate the general feasibility of the ASLA approach in the context of analyzing non-trivial OSS packages.

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Open Source Software maintenance and reuse require identifying and comprehending the applied software licenses. This paper first characterizes software maintenance, and open source software (OSS) reuse which are particularly relevant in this context. The information needs of maintainers and reusers can be supported by reverse engineering tools at different information retrieval levels. The paper presents an automated license retrieval approach called ASLA. User needs, system architecture, tool features, and tool evaluation are presented. The implemented tool features support identifying source file dependencies and licenses in source files, and adding new license templates for identifying licenses. The tool is evaluated against another tool for license information extraction. ASLA requires the source code as available input but is otherwise not limited to OSS. It supports the same programming languages as GCC. License identification coverage is good and the tool is extendable.