Add initial support for crash backtracing

src/include/deepstate/DeepState.h

@@ -35,6 +35,7 @@
 #include <time.h>
 #include <unistd.h>
 #include <fnmatch.h>
+#include <execinfo.h>
 
 #include <deepstate/Log.h>
 #include <deepstate/Compiler.h>
@@ -90,6 +91,7 @@ DECLARE_bool(fork);
 DECLARE_bool(list_tests);
 DECLARE_bool(boring_only);
 DECLARE_bool(run_disabled);
+DECLARE_bool(verbose_crash_trace);
 
 DECLARE_int(min_log_level);
 DECLARE_int(seed);
@@ -521,6 +523,25 @@ extern void DeepState_SaveFailingTest(void);
 /* Save a crashing test to the output test directory. */
 extern void DeepState_SaveCrashingTest(void);
 
+/* Emit test function backtrace after test crashes. */
+static void DeepState_EmitBacktrace(int signum, siginfo_t *sig, void *context) {
+
+  DeepState_LogFormat(DeepState_LogInfo, "Test crashed with: %s", sys_siglist[sig->si_status]);
+
+  void *array[10];
+  size_t size;
+  char **strings;
+
+  size = backtrace(array, 10);
+  strings = backtrace_symbols(array, size);
+
+  for (size_t i = 0; i < size; i++)
+     DeepState_LogFormat(DeepState_LogTrace, "%s", strings[i]);
+
+  free(strings);
+}
+
+
 /* Jump buffer for returning to `DeepState_Run`. */
 extern jmp_buf DeepState_ReturnToRun;
 
@@ -650,7 +671,6 @@ static int DeepState_RunTestNoFork(struct DeepState_TestInfo *test) {
 #if defined(__cplusplus) && defined(__cpp_exceptions)
     try {
 #endif  /* __cplusplus */
-
       test->test_func();  /* Run the test function. */
       return(DeepState_TestRunPass);
 
@@ -692,6 +712,19 @@ static int DeepState_RunTestNoFork(struct DeepState_TestInfo *test) {
 /* Fork and run `test`. */
 static enum DeepState_TestRunResult
 DeepState_ForkAndRunTest(struct DeepState_TestInfo *test) {
+
+  /* If flag is set, install a signal handler for SIGCHLD */
+  /* TODO(alan): use handler as "multiplexer" and handle child signal */
+  if (FLAGS_verbose_crash_trace) {
+    struct sigaction sigact, oldact;
+
+    sigact.sa_flags = SA_SIGINFO | SA_NOCLDWAIT;
+    sigact.sa_sigaction = DeepState_EmitBacktrace;
+
+    sigaction(SIGCHLD, &sigact, &oldact);
+  }
+
+
   pid_t test_pid;
   if (FLAGS_fork) {
     test_pid = fork();
@@ -754,6 +787,7 @@ DeepState_RunSavedTestCase(struct DeepState_TestInfo *test, const char *dir,
       DeepState_LogFormat(DeepState_LogError, "Crashed: %s", test->test_name);
       DeepState_LogFormat(DeepState_LogError, "Test case %s crashed", path);
       free(path);
+
       if (HAS_FLAG_output_test_dir) {
         DeepState_SaveCrashingTest();
       }

src/lib/DeepState.c

@@ -41,10 +41,11 @@ DEFINE_string(output_test_dir, InputOutputGroup, "", "Directory where tests will
 DEFINE_bool(take_over, ExecutionGroup, false, "Replay test cases in take-over mode.");
 DEFINE_bool(abort_on_fail, ExecutionGroup, false, "Abort on file replay failure (useful in file fuzzing).");
 DEFINE_bool(exit_on_fail, ExecutionGroup, false, "Exit with status 255 on test failure.");
-DEFINE_bool(verbose_reads, ExecutionGroup, false, "Report on bytes being read during execution of test.");
 DEFINE_int(min_log_level, ExecutionGroup, 0, "Minimum level of logging to output (default 2, 0=debug, 1=trace, 2=info, ...).");
 DEFINE_int(timeout, ExecutionGroup, 120, "Timeout for brute force fuzzing.");
 DEFINE_uint(num_workers, ExecutionGroup, 1, "Number of workers to spawn for testing and test generation.");
+DEFINE_bool(verbose_reads, ExecutionGroup, false, "Report on bytes being read during execution of test.");
+DEFINE_bool(verbose_crash_trace, ExecutionGroup, false, "If test crashes, report an execution backtrace after abrupt exit.");
 
 /* Fuzzing and symex related options, baked in to perform analysis-related tasks without auxiliary tools */
 DEFINE_bool(fuzz, AnalysisGroup, false, "Perform brute force unguided fuzzing.");
@@ -254,7 +255,7 @@ void DeepState_SwarmAssignCStr_C(const char* file, unsigned line, int stype,
   if (NULL == str) {
     DeepState_Abandon("Attempted to populate null pointer.");
   }
-  char swarm_allowed[256];  
+  char swarm_allowed[256];
   if (allowed == 0) {
     /* In swarm mode, if there is no allowed string, create one over all chars. */
     for (int i = 0; i < 255; i++) {
@@ -306,7 +307,7 @@ char *DeepState_SwarmCStr_C(const char* file, unsigned line, int stype,
   if (NULL == str) {
     DeepState_Abandon("Can't allocate memory");
   }
-  char swarm_allowed[256];  
+  char swarm_allowed[256];
   if (allowed == 0) {
     /* In swarm mode, if there is no allowed string, create one over all chars. */
     for (int i = 0; i < 255; i++) {
@@ -347,14 +348,14 @@ void DeepState_SymbolizeCStr_C(char *begin, const char* allowed) {
 void DeepState_SwarmSymbolizeCStr_C(const char* file, unsigned line, int stype,
 				    char *begin, const char* allowed) {
   if (begin && begin[0]) {
-    char swarm_allowed[256];    
+    char swarm_allowed[256];
     if (allowed == 0) {
       /* In swarm mode, if there is no allowed string, create one over all chars. */
       for (int i = 0; i < 255; i++) {
 	swarm_allowed[i] = i+1;
       }
       swarm_allowed[255] = 0;
-      allowed = (const char*)&swarm_allowed;      
+      allowed = (const char*)&swarm_allowed;
     }
     uint32_t allowed_size = strlen(allowed);
     struct DeepState_SwarmConfig* sc = DeepState_GetSwarmConfig(allowed_size, file, line, stype);
@@ -668,7 +669,7 @@ extern void DeepState_CleanUp() {
     free(DeepState_GeneratedStrings[i]);
   }
   DeepState_GeneratedStringsIndex = 0;
-  
+
   for (int i = 0; i < DeepState_SwarmConfigsIndex; i++) {
     free(DeepState_SwarmConfigs[i]->file);
     free(DeepState_SwarmConfigs[i]->fmap);
@@ -1116,6 +1117,7 @@ enum DeepState_TestRunResult DeepState_FuzzOneTestCase(struct DeepState_TestInfo
 
   enum DeepState_TestRunResult result = DeepState_ForkAndRunTest(test);
 
+
   if (result == DeepState_TestRunCrash) {
     DeepState_LogFormat(DeepState_LogError, "Crashed: %s", test->test_name);