Fault Injection in glibc (FIG)

Most contemporary software applications presuppose an error-free system environment. While this assumption is often correct, the system can break down under excep- tional situations, such as resource exhaustion or net- work failures. Unfortunately, too few developers deal with these issues, since they rarely arise in normal test- ing scenarios and are usually treated as "exceptional" cases to be handled outside the course of regular pro- gramming. We attempt to ameliorate this situation by producing a library (libfig) that induces errors at the application/operating system boundary in a controlled manner. Our intent is that this library be used as a tool for software development and verification, as well as for on-site testing of production systems. We use a working version of this tool to test the behavior of several com- mon UNIX applications under simulated failures, and oer suggestions on how to develop software that is more resilient to failures in the system environment.