Continue thread properly taking into account suspend_count

proctl/threads_darwin.c

@@ -74,8 +74,22 @@ single_step(thread_act_t thread) {
 	kret = thread_set_state(thread, x86_THREAD_STATE64, (thread_state_t)&regs, count);
 	if (kret != KERN_SUCCESS) return kret;
 
-	// Continue here until we've fully decremented suspend_count
-	for (;;) {
+	kret = resume_thread(thread);
+	if (kret != KERN_SUCCESS) return kret;
+
+	return KERN_SUCCESS;
+}
+
+kern_return_t
+resume_thread(thread_act_t thread) {
+	kern_return_t kret;
+    struct thread_basic_info info;
+	unsigned int info_count = THREAD_BASIC_INFO_COUNT;
+
+    kret = thread_info((thread_t)thread, THREAD_BASIC_INFO, (thread_info_t)&info, &info_count);
+	if (kret != KERN_SUCCESS) return kret;
+
+	for (int i = 0; i < info.suspend_count; i++) {
 		kret = thread_resume(thread);
 		if (kret != KERN_SUCCESS) break;
 	}

proctl/threads_darwin.go

@@ -38,10 +38,9 @@ func (t *ThreadContext) resume() error {
 	if PtraceCont(t.Process.Pid, 0) == nil {
 		return nil
 	}
-	for {
-		if C.thread_resume(t.os.thread_act) != C.KERN_SUCCESS {
-			break
-		}
+	kret := C.resume_thread(t.os.thread_act)
+	if kret != C.KERN_SUCCESS {
+		return fmt.Errorf("could not continue thread")
 	}
 	return nil
 }

proctl/threads_darwin.h

@@ -19,4 +19,7 @@ kern_return_t
 single_step(thread_act_t);
 
 kern_return_t
-clear_trap_flag(thread_act_t thread);
+clear_trap_flag(thread_act_t);
+
+kern_return_t
+resume_thread(thread_act_t);