Frequently Asked Questions?

What kinds of test cases work best with RECON2?

ANS: Simple ones! In general, one or two cases "with" the feature you are looking for and one or two "without" seems to work best. Keep the "with" test cases as simple as you can and make the "without" cases similar to them, but omitting the desired feature.

For example, suppose you are trying to locate the code that scrolls a screen window. Do one case that opens the simplest window you can think of, scrolls it, and then closes it. Then do another case that opens the same window and immediately closes it. Then ask r2analyz to do "deterministic" analysis of these two traces.

Is RECON2 good at locating bugs?

ANS: Sometimes yes, sometimes no. If the bug occurs when the program follows an unusual path, then RECON2 will probably find it. If the bug depends instead on particular data values then RECON2 probably won't. We have had some bug-location successes and some failures.

It is a pain to run r2test before each test and r2end afterwards. Is there any better way?

ANS: The only reasons to run r2test are to specify the name of the trace file and to put a comment at the beginning of the trace file for later reference. If you don't run r2test, RECON2 will usually name the trace file "unknown.r2t". If you wish you could just rename this file after each test to something you can remember.

Is there a pre-compiled version for operating system XXXXX?

ANS: Yes, we have a pre-compiled version for MS-DOS Platforms. Upon request, we could also supply a pre-compiled version for Sun OS 4.X and Sun Solaris 2.5+. However, note that to use RECON2, you need a C compiler and the target program to be instrumented. Getting pre-compiled sources will cut very little time from the development effort.

My trace file contained only the comment line, nothing else. What is wrong?

ANS: Were you using the MIN_TRACE option? With MIN_TRACE the trace data is held in memory and is only written when R2Close() is called as your target program exits. If R2Close() is never called, the trace file will be empty as you describe.
To ensure that R2Close() is called, you should either:
• be certain that your program exits through an "exit()" statement that is instrumented. In this case the instrumentor inserts the call to R2Close so a statement like exit(0); becomes exit(R2Close(0));
• or add a call to R2Close() yourself just before your target program exits.




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