Reserch On Safety-rules Checking Technology Of Spacflight C Programs

The embedded softwares of spaceflight need to be highly reliable. In these softwares, there are a large number of programs written by C language. The using of C language is very flexible, but many manners in using C language can lead to secure problems which may impact on the reliability of the embedded softwares of spaceflight. Therefore, the organizations related to spaceflight have presented a C language programming specification for spacecraft software, which is based on C89 standard, MISRA-C 2004 and GJB C language programming rules. It has become the defacto C language programming standard for developing spacecraft software in our country. There are some tools to support the C language programming specification for spacecraft software, but it is not enough. There are loopholes exist. And some rules cannot be checked. So it's very significant to study the technique of checking safety rules of aero C programs. The main work of the paper can be concluded as follows:Firstly, the C programs safety rules and corresponding checking tools are analyzed and summarized. The structure of GCC compiler is described. The principal process phrases, especially the syntax analysis phrase are illustrated.Secondly, based on the above work, an approach by extending GCC front-end to support checking some programming rules in the C language programming specification for spacecraft software is presented. A checking tool SC-RuleChecker for C language programming specification is implemented, by modify and extend the pretreatment handling routine, lexical routine and syntax routine of GCC.Finally, system testing and applications for SC-RuleChecker are conducted. The results show that the tool implements the function of checking safety rules. Compared with the widely used static analysis tools for C language programming, such as LDRA Testbed and QAC, the SC-Rulechecker has significant improvement. The latter can find out the four rules that the former two cannot do. And it reduces the program risk and potential problems. It also improves the reliability of the software.