Allow configurable recursion depth and raise exception when exceeded

src/kuroko.c

@@ -762,7 +762,8 @@ int main(int argc, char * argv[]) {
 	int moduleAsMain = 0;
 	int inspectAfter = 0;
 	int opt;
-	while ((opt = getopt(argc, argv, "+:c:C:dgGim:rstTMSV-:")) != -1) {
+	int maxDepth = -1;
+	while ((opt = getopt(argc, argv, "+:c:C:dgGim:rR:stTMSV-:")) != -1) {
 		switch (opt) {
 			case 'c':
 				runCmd = optarg;
@@ -804,6 +805,9 @@ int main(int argc, char * argv[]) {
 			case 'r':
 				enableRline = 0;
 				break;
+			case 'R':
+				maxDepth = atoi(optarg);
+				break;
 			case 'M':
 				return runString(argv,0,"import kuroko; print(kuroko.module_paths)\n");
 			case 'V':
@@ -834,6 +838,7 @@ int main(int argc, char * argv[]) {
 						" -i          Enter repl after a running -c, -m, or FILE.\n"
 						" -m mod      Run a module as a script.\n"
 						" -r          Disable complex line editing in the REPL.\n"
+						" -R depth    Set maximum recursion depth.\n"
 						" -s          Debug output from the scanner/tokenizer.\n"
 						" -t          Disassemble instructions as they are exceuted.\n"
 						" -T          Write call trace file.\n"
@@ -861,6 +866,10 @@ _finishArgs:
 	findInterpreter(argv);
 	krk_initVM(flags);
 
+	if (maxDepth != -1) {
+		krk_setMaximumRecursionDepth(maxDepth);
+	}
+
 #ifndef KRK_DISABLE_DEBUG
 	krk_debug_registerCallback(debuggerHook);
 #endif

src/kuroko/vm.h

@@ -225,6 +225,7 @@ typedef struct KrkVM {
 
 	KrkThreadState * threads;         /**< Invasive linked list of all VM threads. */
 	FILE * callgrindFile;             /**< File to write unprocessed callgrind data to. */
+	size_t maximumCallDepth;          /**< Maximum recursive call depth. */
 } KrkVM;
 
 /* Thread-specific flags */
@@ -824,3 +825,7 @@ extern KrkValue krk_operator_lt(KrkValue,KrkValue);
  */
 extern KrkValue krk_operator_gt(KrkValue,KrkValue);
 
+/**
+ * @brief Set the maximum recursion call depth.
+ */
+extern void krk_setMaximumRecursionDepth(size_t maxDepth);

src/threads.c

@@ -67,7 +67,7 @@ KRK_FUNC(current_thread,{
 static volatile int _threadLock = 0;
 static void * _startthread(void * _threadObj) {
 	memset(&krk_currentThread, 0, sizeof(KrkThreadState));
-	krk_currentThread.frames = calloc(KRK_CALL_FRAMES_MAX,sizeof(KrkCallFrame));
+	krk_currentThread.frames = calloc(vm.maximumCallDepth,sizeof(KrkCallFrame));
 	vm.globalFlags |= KRK_GLOBAL_THREADS;
 	_obtain_lock(_threadLock);
 	if (vm.threads->next) {

src/vm.c

@@ -734,7 +734,10 @@ _finishKwarg:
 		return 2;
 	}
 
-	if (unlikely(krk_currentThread.frameCount == KRK_CALL_FRAMES_MAX)) goto _errorAfterKeywords;
+	if (unlikely(krk_currentThread.frameCount == vm.maximumCallDepth)) {
+		krk_runtimeError(vm.exceptions->baseException, "maximum recursion depth exceeded");
+		goto _errorAfterKeywords;
+	}
 
 	KrkCallFrame * frame = &krk_currentThread.frames[krk_currentThread.frameCount++];
 	frame->closure = closure;
@@ -1143,12 +1146,23 @@ KRK_FUNC(unload,{
 	}
 })
 
+void krk_setMaximumRecursionDepth(size_t maxDepth) {
+	vm.maximumCallDepth = maxDepth;
+
+	KrkThreadState * thread = vm.threads;
+	while (thread) {
+		thread->frames = realloc(thread->frames, maxDepth * sizeof(KrkCallFrame));
+		thread = thread->next;
+	}
+}
+
 void krk_initVM(int flags) {
 	vm.globalFlags = flags & 0xFF00;
+	vm.maximumCallDepth = KRK_CALL_FRAMES_MAX;
 
 	/* Reset current thread */
 	krk_resetStack();
-	krk_currentThread.frames   = calloc(KRK_CALL_FRAMES_MAX,sizeof(KrkCallFrame));
+	krk_currentThread.frames   = calloc(vm.maximumCallDepth,sizeof(KrkCallFrame));
 	krk_currentThread.flags    = flags & 0x00FF;
 	krk_currentThread.module   = NULL;
 	vm.threads = &krk_currentThread;