Mutator: improve fatal error messages

atrosinenko · Jan 5, 2024 · 1a62750 · 1a62750
1 parent 6762f41
commit 1a62750
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Showing 4 changed files with 13 additions and 14 deletions.
diff --git a/runtime/mutators/afl-generic-mutator.cpp b/runtime/mutators/afl-generic-mutator.cpp
@@ -28,11 +28,6 @@ DECLARE_INT_KNOB_DEF(num_best_effort_iterations,
 
 using namespace kbdysch::mutator;
 
-#ifndef NDEBUG
-// Print a better message.
-#define abort() assert(0)
-#endif
-
 struct mutator_state {
   mutator_state();
 
@@ -219,7 +214,7 @@ size_t afl_custom_fuzz(void *data, uint8_t *buf, size_t buf_size, uint8_t **out_
     ERR("Trying to save log...\n");
     if (!save_log_from_shm(state, state->input.as_data(), "best effort mode")) {
       state->create_debug_dump();
-      abort();
+      FATAL("Cannot save log (input length = %zu)", state->input.size());
     }
     accumulate_important_data(state);
     state->current_journal.load_journal(state->input.as_data());
@@ -228,7 +223,7 @@ size_t afl_custom_fuzz(void *data, uint8_t *buf, size_t buf_size, uint8_t **out_
     ERR("Trying to save log as-is...\n");
     if (!save_log_from_shm(state, buffer_ref(), "best effort mode")) {
       state->create_debug_dump();
-      abort();
+      FATAL("Cannot save log (input length = %zu)", state->input.size());
     }
     accumulate_important_data(state);
     state->record_log_next_action = mutator_state::RECORD_LOG_NONE;

diff --git a/runtime/mutators/helpers.h b/runtime/mutators/helpers.h
@@ -22,12 +22,16 @@ FILE *create_temp_file(const char *prefix, const char *suffix);
 #define DECL_WITH_TYPE(type, new_name, ptr) \
   type *new_name = (type *)(ptr)
 
-#define FATAL(fmt, ...)                                                        \
-  do {                                                                         \
-    fprintf(stderr, "MUTATOR: %s: %d: " fmt, __FILE__, __LINE__, __VA_ARGS__); \
-    abort();                                                                   \
+#define FATAL(fmt, ...)                                                       \
+  do {                                                                        \
+    fprintf(stderr, "\n\n"); /* account for AFL's own UI. */                  \
+    fprintf(stderr, "MUTATOR FATAL ERROR at %s:%d\n", __FILE__, __LINE__);    \
+    fprintf(stderr, "MESSAGE: " fmt, __VA_ARGS__);                            \
+    abort();                                                                  \
   } while (0)
 
+#define FATAL_NOT_IMPLEMENTED(what) FATAL("Not implemented: %s", (what))
+
 #define ERR(...)                                         \
   do {                                                   \
     if (kbdysch::mutator::error_log)                     \

diff --git a/runtime/mutators/mutations.h b/runtime/mutators/mutations.h
@@ -29,14 +29,14 @@ class mutation_strategy {
   // Reimplement if needs_add_buf() returns false
   virtual void render_next_mutation(test_case_storage &output,
                                     buffer_ref input, journal_data &input_journal) {
-    abort();
+    FATAL_NOT_IMPLEMENTED("render_next_mutation (simple)");
   }
 
   // Reimplement if needs_add_buf() returns true
   virtual void render_next_mutation(test_case_storage &output,
                                     buffer_ref input, journal_data &input_journal,
                                     buffer_ref add_buf, journal_data &add_journal) {
-    abort();
+    FATAL_NOT_IMPLEMENTED("render_next_mutation (with extra input)");
   }
 
   virtual ~mutation_strategy() {}

diff --git a/runtime/mutators/variables.cpp b/runtime/mutators/variables.cpp
@@ -84,7 +84,7 @@ class success_rate_variable : public variable {
 
 protected:
   void print_scalar(std::ostringstream &stream, unsigned subscript) override {
-    abort(); // Not implemented
+    FATAL_NOT_IMPLEMENTED("print_scalar");
   }
 
 private: