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POlibsigsegv and responding to a stack overflow
 

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    <p>We are attempting to test student code, and in an effort to automate the process, we'd like to detect if a student's code overflows the stack.</p> <p>I've met with some success using the libsigsegv library and its corresponding stackoverflow_install_handler. It works brilliantly, until the student's code blows the stack twice.</p> <p>For example, here's some sample output:</p> <pre><code>[# ~]$ ledit ./interpreter -&gt; (use solution) -&gt; (fun 1 2) *** Stack overflow detected *** -&gt; (fun 1 2) Signal -10 [# ~] </code></pre> <p>The initial "<strong>* Stack overflow detected *</strong>" is the desirable output. After blowing the stack for the second time, all I get is an unhelpful "Signal -10" and the program stops execution. I'd like to see the stack overflow detected message again, and let the code continue execution.</p> <p>In my stack overflow handler, I'm just printing the overflow detection message to stderr and long jumping back to an "awaiting input state" in the interpreter.</p> <p>Thanks for any help!</p> <p><em>EDIT</em></p> <p>As per caf's suggestion below, we've added a call to sigsegv_leave_handler() like so:</p> <pre><code>static void continuation(void *arg1, void *arg2, void *arg3) { (void)(arg1); (void)(arg2); (void)(arg3); siglongjmp(errorjmp, 1); } static void handler(int emergency, stackoverflow_context_t context) { (void)emergency; (void)context; fprintf(stderr, "\n*** Stack overflow detected ***\n"); fflush(stderr); sigsegv_leave_handler(continuation, NULL, NULL, NULL); } </code></pre> <p>However, the output is still the same.</p>
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    1. CO+1 just for using the buzzword
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    2. CO+1 for trying to detect stack overflow with stackoverflow
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