From a9ab2a2be4a75d4d6422f1c611eb76b79ab1a2a1 Mon Sep 17 00:00:00 2001
From: Josh Holtrop <jholtrop+git@gmail.com>
Date: Tue, 3 Nov 2009 04:01:57 +0000
Subject: [PATCH] added count hook to prevent infinite lua loops from running
 the engine forever

git-svn-id: svn://anubis/anaglym/trunk@151 99a6e188-d820-4881-8870-2d33a10e2619
---
 .todo                     |  1 -
 Engine.cc                 | 19 +++++++++++++++++++
 Engine.h                  |  2 ++
 tests/managed_objects.lua |  4 ++++
 4 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/.todo b/.todo
index a546004..e69de29 100644
--- a/.todo
+++ b/.todo
@@ -1 +0,0 @@
-- debug hooks for loading and execution to halt infinite lua loops
diff --git a/Engine.cc b/Engine.cc
index 80c594d..1b3563f 100644
--- a/Engine.cc
+++ b/Engine.cc
@@ -30,6 +30,8 @@ using namespace std;
     do { EVENT_PRESENT_FLAG(event) = false; } while(0)
 
 #define WHITESPACE " \t\r\n\f"
+#define HOOK_TIMEOUT    10000u
+#define HOOK_STEPS      250000000
 
 #define FP_EQ(a,b) (fabsf(a - b) < 0.0001)
 
@@ -63,6 +65,11 @@ static void cross_product(dVector3 result, dVector3 first, dVector3 second)
     result[2] = first[0] * second[1] - first[1] * second[0];
 }
 
+static void debug_hook(lua_State * L, lua_Debug * debug)
+{
+    g_engine->debug_hook(debug);
+}
+
 /******** Engine functions ********/
 
 Engine::Engine(const string & path, Video & video)
@@ -84,6 +91,7 @@ Engine::Engine(const string & path, Video & video)
     m_autoEndFrame = true;
     m_autoDrawObjects = true;
     m_fileLoader = new EngineFileLoader(this);
+    m_event_time = 0;
 
     size_t pos = path.find_last_of("\\/");
     m_engine_path = (pos != string::npos) ? string(path, 0, pos) : ".";
@@ -131,6 +139,7 @@ bool Engine::load(const char * program)
     if (s == 0)
     {
         // execute Lua program
+        lua_sethook(m_luaState, ::debug_hook, LUA_MASKCOUNT, HOOK_STEPS);
         s = lua_pcall(m_luaState, 0, LUA_MULTRET, 0);
     }
     else
@@ -426,6 +435,15 @@ GLuint Engine::loadTexture(const char * name)
     return m_textureCache.load(path, *m_fileLoader);
 }
 
+void Engine::debug_hook(lua_Debug * debug)
+{
+    Uint32 ticks = SDL_GetTicks();
+    if (ticks - m_event_time > HOOK_TIMEOUT)
+    {
+        ::exit(3);
+    }
+}
+
 /* called by SDL when the update timer expires */
 Uint32 Engine::updateCallback(Uint32 interval, void * param)
 {
@@ -452,6 +470,7 @@ void Engine::run()
     SDL_Event event;
     while (SDL_WaitEvent(&event))
     {
+        m_event_time = SDL_GetTicks();
         switch (event.type)
         {
             case SDL_KEYDOWN:
diff --git a/Engine.h b/Engine.h
index 4f1b2be..97b1301 100644
--- a/Engine.h
+++ b/Engine.h
@@ -133,6 +133,7 @@ class Engine
         void exit();
         bool import(const char * name);
         GLuint loadTexture(const char * name);
+        void debug_hook(lua_Debug * debug);
 
         /* lua services */
         int setCamera(lua_State * L);
@@ -177,6 +178,7 @@ class Engine
         std::map<std::string, bool> m_keysDown;
         SDL_Event       m_updateEvent;
         SDL_Event       m_exitEvent;
+        Uint32          m_event_time;
 
         bool            m_event_update_present;
         bool            m_event_key_down_present;
diff --git a/tests/managed_objects.lua b/tests/managed_objects.lua
index 90342d7..fb7e6e5 100644
--- a/tests/managed_objects.lua
+++ b/tests/managed_objects.lua
@@ -1,4 +1,8 @@
 
+while (9)
+    do
+    end
+
 ground = ag.createStaticPlane(0, 0, 0, 0, 0, 0)
 ground:setColor(0.2, 1.0, 0.2)
 ag.setCamera(10, -10, 10, 0, 0, 0)