21 files changed, 460 insertions, 167 deletions

diff --git a/src/script/cpp_api/s_async.cpp b/src/script/cpp_api/s_async.cpp
index 0619b32c0..dacdcd75a 100644
--- a/src/script/cpp_api/s_async.cpp
+++ b/src/script/cpp_api/s_async.cpp
@@ -32,20 +32,19 @@ extern "C" {
 #include "filesys.h"
 #include "porting.h"
 #include "common/c_internal.h"
+#include "lua_api/l_base.h"
 
 /******************************************************************************/
 AsyncEngine::~AsyncEngine()
 {
-
 	// Request all threads to stop
 	for (AsyncWorkerThread *workerThread : workerThreads) {
 		workerThread->stop();
 	}
 
-
 	// Wake up all threads
-	for (std::vector<AsyncWorkerThread *>::iterator it = workerThreads.begin();
-			it != workerThreads.end(); ++it) {
+	for (auto it : workerThreads) {
+		(void)it;
 		jobQueueCounter.post();
 	}
 
@@ -68,6 +67,7 @@ AsyncEngine::~AsyncEngine()
 /******************************************************************************/
 void AsyncEngine::registerStateInitializer(StateInitializer func)
 {
+	FATAL_ERROR_IF(initDone, "Initializer may not be registered after init");
 	stateInitializers.push_back(func);
 }
 
@@ -85,36 +85,36 @@ void AsyncEngine::initialize(unsigned int numEngines)
 }
 
 /******************************************************************************/
-unsigned int AsyncEngine::queueAsyncJob(const std::string &func,
-		const std::string &params)
+u32 AsyncEngine::queueAsyncJob(std::string &&func, std::string &&params,
+		const std::string &mod_origin)
 {
 	jobQueueMutex.lock();
-	LuaJobInfo toAdd;
-	toAdd.id = jobIdCounter++;
-	toAdd.serializedFunction = func;
-	toAdd.serializedParams = params;
+	u32 jobId = jobIdCounter++;
 
-	jobQueue.push_back(toAdd);
+	jobQueue.emplace_back();
+	auto &to_add = jobQueue.back();
+	to_add.id = jobId;
+	to_add.function = std::move(func);
+	to_add.params = std::move(params);
+	to_add.mod_origin = mod_origin;
 
 	jobQueueCounter.post();
-
 	jobQueueMutex.unlock();
-
-	return toAdd.id;
+	return jobId;
 }
 
 /******************************************************************************/
-LuaJobInfo AsyncEngine::getJob()
+bool AsyncEngine::getJob(LuaJobInfo *job)
 {
 	jobQueueCounter.wait();
 	jobQueueMutex.lock();
 
-	LuaJobInfo retval;
+	bool retval = false;
 
 	if (!jobQueue.empty()) {
-		retval = jobQueue.front();
+		*job = std::move(jobQueue.front());
 		jobQueue.pop_front();
-		retval.valid = true;
+		retval = true;
 	}
 	jobQueueMutex.unlock();
 
@@ -122,10 +122,10 @@ LuaJobInfo AsyncEngine::getJob()
 }
 
 /******************************************************************************/
-void AsyncEngine::putJobResult(const LuaJobInfo &result)
+void AsyncEngine::putJobResult(LuaJobInfo &&result)
 {
 	resultQueueMutex.lock();
-	resultQueue.push_back(result);
+	resultQueue.emplace_back(std::move(result));
 	resultQueueMutex.unlock();
 }
 
@@ -134,26 +134,30 @@ void AsyncEngine::step(lua_State *L)
 {
 	int error_handler = PUSH_ERROR_HANDLER(L);
 	lua_getglobal(L, "core");
-	resultQueueMutex.lock();
+
+	ScriptApiBase *script = ModApiBase::getScriptApiBase(L);
+
+	MutexAutoLock autolock(resultQueueMutex);
 	while (!resultQueue.empty()) {
-		LuaJobInfo jobDone = resultQueue.front();
+		LuaJobInfo j = std::move(resultQueue.front());
 		resultQueue.pop_front();
 
 		lua_getfield(L, -1, "async_event_handler");
-
-		if (lua_isnil(L, -1)) {
+		if (lua_isnil(L, -1))
 			FATAL_ERROR("Async event handler does not exist!");
-		}
-
 		luaL_checktype(L, -1, LUA_TFUNCTION);
 
-		lua_pushinteger(L, jobDone.id);
-		lua_pushlstring(L, jobDone.serializedResult.data(),
-				jobDone.serializedResult.size());
+		lua_pushinteger(L, j.id);
+		lua_pushlstring(L, j.result.data(), j.result.size());
 
-		PCALL_RESL(L, lua_pcall(L, 2, 0, error_handler));
+		// Call handler
+		const char *origin = j.mod_origin.empty() ? nullptr : j.mod_origin.c_str();
+		script->setOriginDirect(origin);
+		int result = lua_pcall(L, 2, 0, error_handler);
+		if (result)
+			script_error(L, result, origin, "<async>");
 	}
-	resultQueueMutex.unlock();
+
 	lua_pop(L, 2); // Pop core and error handler
 }
 
@@ -168,8 +172,8 @@ void AsyncEngine::prepareEnvironment(lua_State* L, int top)
 /******************************************************************************/
 AsyncWorkerThread::AsyncWorkerThread(AsyncEngine* jobDispatcher,
 		const std::string &name) :
-	Thread(name),
 	ScriptApiBase(ScriptingType::Async),
+	Thread(name),
 	jobDispatcher(jobDispatcher)
 {
 	lua_State *L = getStack();
@@ -196,9 +200,9 @@ void* AsyncWorkerThread::run()
 {
 	lua_State *L = getStack();
 
-	std::string script = getServer()->getBuiltinLuaPath() + DIR_DELIM + "init.lua";
 	try {
-		loadScript(script);
+		loadMod(getServer()->getBuiltinLuaPath() + DIR_DELIM + "init.lua",
+			BUILTIN_MOD_NAME);
 	} catch (const ModError &e) {
 		errorstream << "Execution of async base environment failed: "
 			<< e.what() << std::endl;
@@ -213,44 +217,44 @@ void* AsyncWorkerThread::run()
 	}
 
 	// Main loop
+	LuaJobInfo j;
 	while (!stopRequested()) {
 		// Wait for job
-		LuaJobInfo toProcess = jobDispatcher->getJob();
-
-		if (!toProcess.valid || stopRequested()) {
+		if (!jobDispatcher->getJob(&j) || stopRequested())
 			continue;
-		}
 
 		lua_getfield(L, -1, "job_processor");
-		if (lua_isnil(L, -1)) {
+		if (lua_isnil(L, -1))
 			FATAL_ERROR("Unable to get async job processor!");
-		}
-
 		luaL_checktype(L, -1, LUA_TFUNCTION);
 
-		// Call it
-		lua_pushlstring(L,
-				toProcess.serializedFunction.data(),
-				toProcess.serializedFunction.size());
-		lua_pushlstring(L,
-				toProcess.serializedParams.data(),
-				toProcess.serializedParams.size());
+		if (luaL_loadbuffer(L, j.function.data(), j.function.size(), "=(async)")) {
+			errorstream << "ASYNC WORKER: Unable to deserialize function" << std::endl;
+			lua_pushnil(L);
+		}
+		lua_pushlstring(L, j.params.data(), j.params.size());
 
+		// Call it
+		setOriginDirect(j.mod_origin.empty() ? nullptr : j.mod_origin.c_str());
 		int result = lua_pcall(L, 2, 1, error_handler);
 		if (result) {
-			PCALL_RES(result);
-			toProcess.serializedResult = "";
+			try {
+				scriptError(result, "<async>");
+			} catch (const ModError &e) {
+				errorstream << e.what() << std::endl;
+			}
 		} else {
 			// Fetch result
 			size_t length;
 			const char *retval = lua_tolstring(L, -1, &length);
-			toProcess.serializedResult = std::string(retval, length);
+			j.result.assign(retval, length);
 		}
 
 		lua_pop(L, 1);  // Pop retval
 
 		// Put job result
-		jobDispatcher->putJobResult(toProcess);
+		if (!j.result.empty())
+			jobDispatcher->putJobResult(std::move(j));
 	}
 
 	lua_pop(L, 2);  // Pop core and error handler
diff --git a/src/script/cpp_api/s_async.h b/src/script/cpp_api/s_async.h
index 99a4f891c..697cb0221 100644
--- a/src/script/cpp_api/s_async.h
+++ b/src/script/cpp_api/s_async.h
@@ -21,7 +21,6 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 
 #include <vector>
 #include <deque>
-#include <map>
 
 #include "threading/semaphore.h"
 #include "threading/thread.h"
@@ -39,26 +38,29 @@ struct LuaJobInfo
 {
 	LuaJobInfo() = default;
 
-	// Function to be called in async environment
-	std::string serializedFunction = "";
-	// Parameter to be passed to function
-	std::string serializedParams = "";
-	// Result of function call
-	std::string serializedResult = "";
+	// Function to be called in async environment (from string.dump)
+	std::string function;
+	// Parameter to be passed to function (serialized)
+	std::string params;
+	// Result of function call (serialized)
+	std::string result;
+	// Name of the mod who invoked this call
+	std::string mod_origin;
 	// JobID used to identify a job and match it to callback
-	unsigned int id = 0;
-
-	bool valid = false;
+	u32 id;
 };
 
 // Asynchronous working environment
-class AsyncWorkerThread : public Thread, public ScriptApiBase {
+class AsyncWorkerThread : public Thread, virtual public ScriptApiBase {
+	friend class AsyncEngine;
 public:
-	AsyncWorkerThread(AsyncEngine* jobDispatcher, const std::string &name);
 	virtual ~AsyncWorkerThread();
 
 	void *run();
 
+protected:
+	AsyncWorkerThread(AsyncEngine* jobDispatcher, const std::string &name);
+
 private:
 	AsyncEngine *jobDispatcher = nullptr;
 };
@@ -89,7 +91,8 @@ public:
 	 * @param params Serialized parameters
 	 * @return jobid The job is queued
 	 */
-	unsigned int queueAsyncJob(const std::string &func, const std::string &params);
+	u32 queueAsyncJob(std::string &&func, std::string &&params,
+			const std::string &mod_origin = "");
 
 	/**
 	 * Engine step to process finished jobs
@@ -102,15 +105,16 @@ protected:
 	/**
 	 * Get a Job from queue to be processed
 	 *  this function blocks until a job is ready
-	 * @return a job to be processed
+	 * @param job a job to be processed
+	 * @return whether a job was available
 	 */
-	LuaJobInfo getJob();
+	bool getJob(LuaJobInfo *job);
 
 	/**
 	 * Put a Job result back to result queue
 	 * @param result result of completed job
 	 */
-	void putJobResult(const LuaJobInfo &result);
+	void putJobResult(LuaJobInfo &&result);
 
 	/**
 	 * Initialize environment with current registred functions
@@ -129,11 +133,10 @@ private:
 	std::vector<StateInitializer> stateInitializers;
 
 	// Internal counter to create job IDs
-	unsigned int jobIdCounter = 0;
+	u32 jobIdCounter = 0;
 
 	// Mutex to protect job queue
 	std::mutex jobQueueMutex;
-
 	// Job queue
 	std::deque<LuaJobInfo> jobQueue;
 
diff --git a/src/script/cpp_api/s_base.cpp b/src/script/cpp_api/s_base.cpp
index f965975a3..f7b8a5102 100644
--- a/src/script/cpp_api/s_base.cpp
+++ b/src/script/cpp_api/s_base.cpp
@@ -37,6 +37,8 @@ extern "C" {
 #include "lualib.h"
 #if USE_LUAJIT
 	#include "luajit.h"
+#else
+	#include "bit.h"
 #endif
 }
 
@@ -88,6 +90,11 @@ ScriptApiBase::ScriptApiBase(ScriptingType type):
 	else
 		luaL_openlibs(m_luastack);
 
+	// Load bit library
+	lua_pushcfunction(m_luastack, luaopen_bit);
+	lua_pushstring(m_luastack, LUA_BITLIBNAME);
+	lua_call(m_luastack, 1, 0);
+
 	// Make the ScriptApiBase* accessible to ModApiBase
 #if INDIRECT_SCRIPTAPI_RIDX
 	*(void **)(lua_newuserdata(m_luastack, sizeof(void *))) = this;
@@ -331,13 +338,9 @@ void ScriptApiBase::setOriginDirect(const char *origin)
 
 void ScriptApiBase::setOriginFromTableRaw(int index, const char *fxn)
 {
-#ifdef SCRIPTAPI_DEBUG
 	lua_State *L = getStack();
-
 	m_last_run_mod = lua_istable(L, index) ?
 		getstringfield_default(L, index, "mod_origin", "") : "";
-	//printf(">>>> running %s for mod: %s\n", fxn, m_last_run_mod.c_str());
-#endif
 }
 
 /*
diff --git a/src/script/cpp_api/s_base.h b/src/script/cpp_api/s_base.h
index 86f7f7bac..244d81605 100644
--- a/src/script/cpp_api/s_base.h
+++ b/src/script/cpp_api/s_base.h
@@ -39,7 +39,6 @@ extern "C" {
 #include "config.h"
 
 #define SCRIPTAPI_LOCK_DEBUG
-#define SCRIPTAPI_DEBUG
 
 // MUST be an invalid mod name so that mods can't
 // use that name to bypass security!
@@ -108,7 +107,9 @@ public:
 	Client* getClient();
 #endif
 
-	std::string getOrigin() { return m_last_run_mod; }
+	// IMPORTANT: these cannot be used for any security-related uses, they exist
+	// only to enrich error messages
+	const std::string &getOrigin() { return m_last_run_mod; }
 	void setOriginDirect(const char *origin);
 	void setOriginFromTableRaw(int index, const char *fxn);
 
@@ -124,11 +125,23 @@ protected:
 	friend class ModApiEnvMod;
 	friend class LuaVoxelManip;
 
+	/*
+		Subtle edge case with coroutines: If for whatever reason you have a
+		method in a subclass that's called from existing lua_CFunction
+		(any of the l_*.cpp files) then make it static and take the lua_State*
+		as an argument. This is REQUIRED because getStack() will not return the
+		correct state if called inside coroutines.
+
+		Also note that src/script/common/ is the better place for such helpers.
+	*/
 	lua_State* getStack()
 		{ return m_luastack; }
 
+	// Checks that stack size is sane
 	void realityCheck();
+	// Takes an error from lua_pcall and throws it as a LuaError
 	void scriptError(int result, const char *fxn);
+	// Dumps stack contents for debugging
 	void stackDump(std::ostream &o);
 
 	void setGameDef(IGameDef* gamedef) { m_gamedef = gamedef; }
diff --git a/src/script/cpp_api/s_client.cpp b/src/script/cpp_api/s_client.cpp
index f2cc9730b..c889fffa0 100644
--- a/src/script/cpp_api/s_client.cpp
+++ b/src/script/cpp_api/s_client.cpp
@@ -33,7 +33,11 @@ void ScriptApiClient::on_mods_loaded()
 	lua_getglobal(L, "core");
 	lua_getfield(L, -1, "registered_on_mods_loaded");
 	// Call callbacks
-	runCallbacks(0, RUN_CALLBACKS_MODE_FIRST);
+	try {
+		runCallbacks(0, RUN_CALLBACKS_MODE_FIRST);
+	} catch (LuaError &e) {
+		getClient()->setFatalError(e);
+	}
 }
 
 void ScriptApiClient::on_shutdown()
@@ -44,7 +48,11 @@ void ScriptApiClient::on_shutdown()
 	lua_getglobal(L, "core");
 	lua_getfield(L, -1, "registered_on_shutdown");
 	// Call callbacks
-	runCallbacks(0, RUN_CALLBACKS_MODE_FIRST);
+	try {
+		runCallbacks(0, RUN_CALLBACKS_MODE_FIRST);
+	} catch (LuaError &e) {
+		getClient()->setFatalError(e);
+	}
 }
 
 bool ScriptApiClient::on_sending_message(const std::string &message)
@@ -56,7 +64,12 @@ bool ScriptApiClient::on_sending_message(const std::string &message)
 	lua_getfield(L, -1, "registered_on_sending_chat_message");
 	// Call callbacks
 	lua_pushstring(L, message.c_str());
-	runCallbacks(1, RUN_CALLBACKS_MODE_OR_SC);
+	try {
+		runCallbacks(1, RUN_CALLBACKS_MODE_OR_SC);
+	} catch (LuaError &e) {
+		getClient()->setFatalError(e);
+		return true;
+	}
 	return readParam<bool>(L, -1);
 }
 
@@ -69,7 +82,12 @@ bool ScriptApiClient::on_receiving_message(const std::string &message)
 	lua_getfield(L, -1, "registered_on_receiving_chat_message");
 	// Call callbacks
 	lua_pushstring(L, message.c_str());
-	runCallbacks(1, RUN_CALLBACKS_MODE_OR_SC);
+	try {
+		runCallbacks(1, RUN_CALLBACKS_MODE_OR_SC);
+	} catch (LuaError &e) {
+		getClient()->setFatalError(e);
+		return true;
+	}
 	return readParam<bool>(L, -1);
 }
 
@@ -82,7 +100,11 @@ void ScriptApiClient::on_damage_taken(int32_t damage_amount)
 	lua_getfield(L, -1, "registered_on_damage_taken");
 	// Call callbacks
 	lua_pushinteger(L, damage_amount);
-	runCallbacks(1, RUN_CALLBACKS_MODE_OR_SC);
+	try {
+		runCallbacks(1, RUN_CALLBACKS_MODE_OR_SC);
+	} catch (LuaError &e) {
+		getClient()->setFatalError(e);
+	}
 }
 
 void ScriptApiClient::on_hp_modification(int32_t newhp)
@@ -94,7 +116,11 @@ void ScriptApiClient::on_hp_modification(int32_t newhp)
 	lua_getfield(L, -1, "registered_on_hp_modification");
 	// Call callbacks
 	lua_pushinteger(L, newhp);
-	runCallbacks(1, RUN_CALLBACKS_MODE_OR_SC);
+	try {
+		runCallbacks(1, RUN_CALLBACKS_MODE_OR_SC);
+	} catch (LuaError &e) {
+		getClient()->setFatalError(e);
+	}
 }
 
 void ScriptApiClient::on_death()
@@ -105,7 +131,11 @@ void ScriptApiClient::on_death()
 	lua_getglobal(L, "core");
 	lua_getfield(L, -1, "registered_on_death");
 	// Call callbacks
-	runCallbacks(0, RUN_CALLBACKS_MODE_FIRST);
+	try {
+		runCallbacks(0, RUN_CALLBACKS_MODE_FIRST);
+	} catch (LuaError &e) {
+		getClient()->setFatalError(e);
+	}
 }
 
 void ScriptApiClient::environment_step(float dtime)
@@ -120,8 +150,7 @@ void ScriptApiClient::environment_step(float dtime)
 	try {
 		runCallbacks(1, RUN_CALLBACKS_MODE_FIRST);
 	} catch (LuaError &e) {
-		getClient()->setFatalError(std::string("Client environment_step: ") + e.what() + "\n"
-				+ script_get_backtrace(L));
+		getClient()->setFatalError(e);
 	}
 }
 
@@ -146,7 +175,11 @@ void ScriptApiClient::on_formspec_input(const std::string &formname,
 		lua_pushlstring(L, value.c_str(), value.size());
 		lua_settable(L, -3);
 	}
-	runCallbacks(2, RUN_CALLBACKS_MODE_OR_SC);
+	try {
+		runCallbacks(2, RUN_CALLBACKS_MODE_OR_SC);
+	} catch (LuaError &e) {
+		getClient()->setFatalError(e);
+	}
 }
 
 bool ScriptApiClient::on_dignode(v3s16 p, MapNode node)
@@ -164,7 +197,12 @@ bool ScriptApiClient::on_dignode(v3s16 p, MapNode node)
 	pushnode(L, node, ndef);
 
 	// Call functions
-	runCallbacks(2, RUN_CALLBACKS_MODE_OR);
+	try {
+		runCallbacks(2, RUN_CALLBACKS_MODE_OR);
+	} catch (LuaError &e) {
+		getClient()->setFatalError(e);
+		return true;
+	}
 	return lua_toboolean(L, -1);
 }
 
@@ -183,7 +221,12 @@ bool ScriptApiClient::on_punchnode(v3s16 p, MapNode node)
 	pushnode(L, node, ndef);
 
 	// Call functions
-	runCallbacks(2, RUN_CALLBACKS_MODE_OR);
+	try {
+		runCallbacks(2, RUN_CALLBACKS_MODE_OR);
+	} catch (LuaError &e) {
+		getClient()->setFatalError(e);
+		return true;
+	}
 	return readParam<bool>(L, -1);
 }
 
@@ -200,7 +243,12 @@ bool ScriptApiClient::on_placenode(const PointedThing &pointed, const ItemDefini
 	push_item_definition(L, item);
 
 	// Call functions
-	runCallbacks(2, RUN_CALLBACKS_MODE_OR);
+	try {
+		runCallbacks(2, RUN_CALLBACKS_MODE_OR);
+	} catch (LuaError &e) {
+		getClient()->setFatalError(e);
+		return true;
+	}
 	return readParam<bool>(L, -1);
 }
 
@@ -217,7 +265,12 @@ bool ScriptApiClient::on_item_use(const ItemStack &item, const PointedThing &poi
 	push_pointed_thing(L, pointed, true);
 
 	// Call functions
-	runCallbacks(2, RUN_CALLBACKS_MODE_OR);
+	try {
+		runCallbacks(2, RUN_CALLBACKS_MODE_OR);
+	} catch (LuaError &e) {
+		getClient()->setFatalError(e);
+		return true;
+	}
 	return readParam<bool>(L, -1);
 }
 
@@ -238,7 +291,12 @@ bool ScriptApiClient::on_inventory_open(Inventory *inventory)
 		lua_rawset(L, -3);
 	}
 
-	runCallbacks(1, RUN_CALLBACKS_MODE_OR);
+	try {
+		runCallbacks(1, RUN_CALLBACKS_MODE_OR);
+	} catch (LuaError &e) {
+		getClient()->setFatalError(e);
+		return true;
+	}
 	return readParam<bool>(L, -1);
 }
 
diff --git a/src/script/cpp_api/s_entity.cpp b/src/script/cpp_api/s_entity.cpp
index 746f7013e..06337b9e8 100644
--- a/src/script/cpp_api/s_entity.cpp
+++ b/src/script/cpp_api/s_entity.cpp
@@ -240,7 +240,7 @@ void ScriptApiEntity::luaentity_Step(u16 id, float dtime,
 //                       tool_capabilities, direction, damage)
 bool ScriptApiEntity::luaentity_Punch(u16 id,
 		ServerActiveObject *puncher, float time_from_last_punch,
-		const ToolCapabilities *toolcap, v3f dir, s16 damage)
+		const ToolCapabilities *toolcap, v3f dir, s32 damage)
 {
 	SCRIPTAPI_PRECHECKHEADER
 
diff --git a/src/script/cpp_api/s_entity.h b/src/script/cpp_api/s_entity.h
index b52f6e447..7658ae922 100644
--- a/src/script/cpp_api/s_entity.h
+++ b/src/script/cpp_api/s_entity.h
@@ -42,7 +42,7 @@ public:
 		const collisionMoveResult *moveresult);
 	bool luaentity_Punch(u16 id,
 			ServerActiveObject *puncher, float time_from_last_punch,
-			const ToolCapabilities *toolcap, v3f dir, s16 damage);
+			const ToolCapabilities *toolcap, v3f dir, s32 damage);
 	bool luaentity_on_death(u16 id, ServerActiveObject *killer);
 	void luaentity_Rightclick(u16 id, ServerActiveObject *clicker);
 	void luaentity_on_attach_child(u16 id, ServerActiveObject *child);
diff --git a/src/script/cpp_api/s_env.cpp b/src/script/cpp_api/s_env.cpp
index 8da5debaa..874c37b6e 100644
--- a/src/script/cpp_api/s_env.cpp
+++ b/src/script/cpp_api/s_env.cpp
@@ -25,6 +25,8 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "mapgen/mapgen.h"
 #include "lua_api/l_env.h"
 #include "server.h"
+#include "script/common/c_content.h"
+
 
 void ScriptApiEnv::environment_OnGenerated(v3s16 minp, v3s16 maxp,
 	u32 blockseed)
@@ -51,13 +53,7 @@ void ScriptApiEnv::environment_Step(float dtime)
 	lua_getfield(L, -1, "registered_globalsteps");
 	// Call callbacks
 	lua_pushnumber(L, dtime);
-	try {
-		runCallbacks(1, RUN_CALLBACKS_MODE_FIRST);
-	} catch (LuaError &e) {
-		getServer()->setAsyncFatalError(
-				std::string("environment_Step: ") + e.what() + "\n"
-				+ script_get_backtrace(L));
-	}
+	runCallbacks(1, RUN_CALLBACKS_MODE_FIRST);
 }
 
 void ScriptApiEnv::player_event(ServerActiveObject *player, const std::string &type)
@@ -74,13 +70,7 @@ void ScriptApiEnv::player_event(ServerActiveObject *player, const std::string &t
 	// Call callbacks
 	objectrefGetOrCreate(L, player);   // player
 	lua_pushstring(L,type.c_str()); // event type
-	try {
-		runCallbacks(2, RUN_CALLBACKS_MODE_FIRST);
-	} catch (LuaError &e) {
-		getServer()->setAsyncFatalError(
-				std::string("player_event: ") + e.what() + "\n"
-				+ script_get_backtrace(L) );
-	}
+	runCallbacks(2, RUN_CALLBACKS_MODE_FIRST);
 }
 
 void ScriptApiEnv::initializeEnvironment(ServerEnvironment *env)
@@ -150,13 +140,19 @@ void ScriptApiEnv::initializeEnvironment(ServerEnvironment *env)
 
 		bool simple_catch_up = true;
 		getboolfield(L, current_abm, "catch_up", simple_catch_up);
+		
+		s16 min_y = INT16_MIN;
+		getintfield(L, current_abm, "min_y", min_y);
+		
+		s16 max_y = INT16_MAX;
+		getintfield(L, current_abm, "max_y", max_y);
 
 		lua_getfield(L, current_abm, "action");
 		luaL_checktype(L, current_abm + 1, LUA_TFUNCTION);
 		lua_pop(L, 1);
 
 		LuaABM *abm = new LuaABM(L, id, trigger_contents, required_neighbors,
-			trigger_interval, trigger_chance, simple_catch_up);
+			trigger_interval, trigger_chance, simple_catch_up, min_y, max_y);
 
 		env->addActiveBlockModifier(abm);
 
@@ -249,9 +245,8 @@ void ScriptApiEnv::on_emerge_area_completion(
 	try {
 		PCALL_RES(lua_pcall(L, 4, 0, error_handler));
 	} catch (LuaError &e) {
-		server->setAsyncFatalError(
-				std::string("on_emerge_area_completion: ") + e.what() + "\n"
-				+ script_get_backtrace(L));
+		// Note: don't throw here, we still need to run the cleanup code below
+		server->setAsyncFatalError(e);
 	}
 
 	lua_pop(L, 1); // Pop error handler
@@ -261,3 +256,35 @@ void ScriptApiEnv::on_emerge_area_completion(
 		luaL_unref(L, LUA_REGISTRYINDEX, state->args_ref);
 	}
 }
+
+void ScriptApiEnv::on_liquid_transformed(
+	const std::vector<std::pair<v3s16, MapNode>> &list)
+{
+	SCRIPTAPI_PRECHECKHEADER
+
+	// Get core.registered_on_liquid_transformed
+	lua_getglobal(L, "core");
+	lua_getfield(L, -1, "registered_on_liquid_transformed");
+	luaL_checktype(L, -1, LUA_TTABLE);
+	lua_remove(L, -2);
+
+	// Skip converting list and calling hook if there are
+	// no registered callbacks.
+	if(lua_objlen(L, -1) < 1) return;
+
+	// Convert the list to a pos array and a node array for lua
+	int index = 1;
+	const NodeDefManager *ndef = getEnv()->getGameDef()->ndef();
+	lua_createtable(L, list.size(), 0);
+	lua_createtable(L, list.size(), 0);
+	for(std::pair<v3s16, MapNode> p : list) {
+		lua_pushnumber(L, index);
+		push_v3s16(L, p.first);
+		lua_rawset(L, -4);
+		lua_pushnumber(L, index++);
+		pushnode(L, p.second, ndef);
+		lua_rawset(L, -3);
+	}
+
+	runCallbacks(2, RUN_CALLBACKS_MODE_FIRST);
+}
diff --git a/src/script/cpp_api/s_env.h b/src/script/cpp_api/s_env.h
index 232a08aaf..090858f17 100644
--- a/src/script/cpp_api/s_env.h
+++ b/src/script/cpp_api/s_env.h
@@ -21,6 +21,8 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 
 #include "cpp_api/s_base.h"
 #include "irr_v3d.h"
+#include "mapnode.h"
+#include <vector>
 
 class ServerEnvironment;
 struct ScriptCallbackState;
@@ -41,5 +43,8 @@ public:
 	void on_emerge_area_completion(v3s16 blockpos, int action,
 		ScriptCallbackState *state);
 
+	// Called after liquid transform changes
+	void on_liquid_transformed(const std::vector<std::pair<v3s16, MapNode>> &list);
+
 	void initializeEnvironment(ServerEnvironment *env);
 };
diff --git a/src/script/cpp_api/s_item.cpp b/src/script/cpp_api/s_item.cpp
index 24955cefc..b1916070e 100644
--- a/src/script/cpp_api/s_item.cpp
+++ b/src/script/cpp_api/s_item.cpp
@@ -29,6 +29,9 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "inventory.h"
 #include "inventorymanager.h"
 
+#define WRAP_LUAERROR(e, detail) \
+	LuaError(std::string(__FUNCTION__) + ": " + (e).what() + ". " detail)
+
 bool ScriptApiItem::item_OnDrop(ItemStack &item,
 		ServerActiveObject *dropper, v3f pos)
 {
@@ -49,20 +52,21 @@ bool ScriptApiItem::item_OnDrop(ItemStack &item,
 		try {
 			item = read_item(L, -1, getServer()->idef());
 		} catch (LuaError &e) {
-			throw LuaError(std::string(e.what()) + ". item=" + item.name);
+			throw WRAP_LUAERROR(e, "item=" + item.name);
 		}
 	}
 	lua_pop(L, 2);  // Pop item and error handler
 	return true;
 }
 
-bool ScriptApiItem::item_OnPlace(ItemStack &item,
+bool ScriptApiItem::item_OnPlace(Optional<ItemStack> &ret_item,
 		ServerActiveObject *placer, const PointedThing &pointed)
 {
 	SCRIPTAPI_PRECHECKHEADER
 
 	int error_handler = PUSH_ERROR_HANDLER(L);
 
+	const ItemStack &item = *ret_item;
 	// Push callback function on stack
 	if (!getItemCallback(item.name.c_str(), "on_place"))
 		return false;
@@ -79,22 +83,25 @@ bool ScriptApiItem::item_OnPlace(ItemStack &item,
 	PCALL_RES(lua_pcall(L, 3, 1, error_handler));
 	if (!lua_isnil(L, -1)) {
 		try {
-			item = read_item(L, -1, getServer()->idef());
+			ret_item = read_item(L, -1, getServer()->idef());
 		} catch (LuaError &e) {
-			throw LuaError(std::string(e.what()) + ". item=" + item.name);
+			throw WRAP_LUAERROR(e, "item=" + item.name);
 		}
+	} else {
+		ret_item = nullopt;
 	}
 	lua_pop(L, 2);  // Pop item and error handler
 	return true;
 }
 
-bool ScriptApiItem::item_OnUse(ItemStack &item,
+bool ScriptApiItem::item_OnUse(Optional<ItemStack> &ret_item,
 		ServerActiveObject *user, const PointedThing &pointed)
 {
 	SCRIPTAPI_PRECHECKHEADER
 
 	int error_handler = PUSH_ERROR_HANDLER(L);
 
+	const ItemStack &item = *ret_item;
 	// Push callback function on stack
 	if (!getItemCallback(item.name.c_str(), "on_use"))
 		return false;
@@ -106,22 +113,25 @@ bool ScriptApiItem::item_OnUse(ItemStack &item,
 	PCALL_RES(lua_pcall(L, 3, 1, error_handler));
 	if(!lua_isnil(L, -1)) {
 		try {
-			item = read_item(L, -1, getServer()->idef());
+			ret_item = read_item(L, -1, getServer()->idef());
 		} catch (LuaError &e) {
-			throw LuaError(std::string(e.what()) + ". item=" + item.name);
+			throw WRAP_LUAERROR(e, "item=" + item.name);
 		}
+	} else {
+		ret_item = nullopt;
 	}
 	lua_pop(L, 2);  // Pop item and error handler
 	return true;
 }
 
-bool ScriptApiItem::item_OnSecondaryUse(ItemStack &item,
+bool ScriptApiItem::item_OnSecondaryUse(Optional<ItemStack> &ret_item,
 		ServerActiveObject *user, const PointedThing &pointed)
 {
 	SCRIPTAPI_PRECHECKHEADER
 
 	int error_handler = PUSH_ERROR_HANDLER(L);
 
+	const ItemStack &item = *ret_item;
 	if (!getItemCallback(item.name.c_str(), "on_secondary_use"))
 		return false;
 
@@ -131,10 +141,12 @@ bool ScriptApiItem::item_OnSecondaryUse(ItemStack &item,
 	PCALL_RES(lua_pcall(L, 3, 1, error_handler));
 	if (!lua_isnil(L, -1)) {
 		try {
-			item = read_item(L, -1, getServer()->idef());
+			ret_item = read_item(L, -1, getServer()->idef());
 		} catch (LuaError &e) {
-			throw LuaError(std::string(e.what()) + ". item=" + item.name);
+			throw WRAP_LUAERROR(e, "item=" + item.name);
 		}
+	} else {
+		ret_item = nullopt;
 	}
 	lua_pop(L, 2);  // Pop item and error handler
 	return true;
@@ -165,7 +177,7 @@ bool ScriptApiItem::item_OnCraft(ItemStack &item, ServerActiveObject *user,
 		try {
 			item = read_item(L, -1, getServer()->idef());
 		} catch (LuaError &e) {
-			throw LuaError(std::string(e.what()) + ". item=" + item.name);
+			throw WRAP_LUAERROR(e, "item=" + item.name);
 		}
 	}
 	lua_pop(L, 2);  // Pop item and error handler
@@ -197,7 +209,7 @@ bool ScriptApiItem::item_CraftPredict(ItemStack &item, ServerActiveObject *user,
 		try {
 			item = read_item(L, -1, getServer()->idef());
 		} catch (LuaError &e) {
-			throw LuaError(std::string(e.what()) + ". item=" + item.name);
+			throw WRAP_LUAERROR(e, "item=" + item.name);
 		}
 	}
 	lua_pop(L, 2);  // Pop item and error handler
diff --git a/src/script/cpp_api/s_item.h b/src/script/cpp_api/s_item.h
index 25a3501f9..5015d8bd4 100644
--- a/src/script/cpp_api/s_item.h
+++ b/src/script/cpp_api/s_item.h
@@ -21,6 +21,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 
 #include "cpp_api/s_base.h"
 #include "irr_v3d.h"
+#include "util/Optional.h"
 
 struct PointedThing;
 struct ItemStack;
@@ -35,13 +36,20 @@ class ScriptApiItem
 : virtual public ScriptApiBase
 {
 public:
+	/*
+	 * Functions with Optional<ItemStack> are for callbacks where Lua may
+	 * want to prevent the engine from modifying the inventory after it's done.
+	 * This has a longer backstory where on_use may need to empty the player's
+	 * inventory without the engine interfering (see issue #6546).
+	 */
+
 	bool item_OnDrop(ItemStack &item,
 			ServerActiveObject *dropper, v3f pos);
-	bool item_OnPlace(ItemStack &item,
+	bool item_OnPlace(Optional<ItemStack> &item,
 			ServerActiveObject *placer, const PointedThing &pointed);
-	bool item_OnUse(ItemStack &item,
+	bool item_OnUse(Optional<ItemStack> &item,
 			ServerActiveObject *user, const PointedThing &pointed);
-	bool item_OnSecondaryUse(ItemStack &item,
+	bool item_OnSecondaryUse(Optional<ItemStack> &item,
 			ServerActiveObject *user, const PointedThing &pointed);
 	bool item_OnCraft(ItemStack &item, ServerActiveObject *user,
 			const InventoryList *old_craft_grid, const InventoryLocation &craft_inv);
diff --git a/src/script/cpp_api/s_mainmenu.h b/src/script/cpp_api/s_mainmenu.h
index aef36ce39..470577a29 100644
--- a/src/script/cpp_api/s_mainmenu.h
+++ b/src/script/cpp_api/s_mainmenu.h
@@ -38,7 +38,7 @@ public:
 	void handleMainMenuEvent(std::string text);
 
 	/**
-	 * process field data recieved from formspec
+	 * process field data received from formspec
 	 * @param fields data in field format
 	 */
 	void handleMainMenuButtons(const StringMap &fields);
diff --git a/src/script/cpp_api/s_node.cpp b/src/script/cpp_api/s_node.cpp
index f23fbfbde..029cb6308 100644
--- a/src/script/cpp_api/s_node.cpp
+++ b/src/script/cpp_api/s_node.cpp
@@ -65,6 +65,7 @@ struct EnumString ScriptApiNode::es_ContentParamType2[] =
 		{CPT2_COLORED_FACEDIR, "colorfacedir"},
 		{CPT2_COLORED_WALLMOUNTED, "colorwallmounted"},
 		{CPT2_GLASSLIKE_LIQUID_LEVEL, "glasslikeliquidlevel"},
+		{CPT2_COLORED_DEGROTATE, "colordegrotate"},
 		{0, NULL},
 	};
 
diff --git a/src/script/cpp_api/s_node.h b/src/script/cpp_api/s_node.h
index 3f771c838..3c6a8445b 100644
--- a/src/script/cpp_api/s_node.h
+++ b/src/script/cpp_api/s_node.h
@@ -53,6 +53,7 @@ public:
 	static struct EnumString es_ContentParamType[];
 	static struct EnumString es_ContentParamType2[];
 	static struct EnumString es_LiquidType[];
+	static struct EnumString es_LiquidMoveType[];
 	static struct EnumString es_NodeBoxType[];
 	static struct EnumString es_TextureAlphaMode[];
 };
diff --git a/src/script/cpp_api/s_nodemeta.cpp b/src/script/cpp_api/s_nodemeta.cpp
index c081e9fc4..7ab3757f3 100644
--- a/src/script/cpp_api/s_nodemeta.cpp
+++ b/src/script/cpp_api/s_nodemeta.cpp
@@ -43,7 +43,7 @@ int ScriptApiNodemeta::nodemeta_inventory_AllowMove(
 		return 0;
 
 	// Push callback function on stack
-	std::string nodename = ndef->get(node).name;
+	const auto &nodename = ndef->get(node).name;
 	if (!getItemCallback(nodename.c_str(), "allow_metadata_inventory_move", &ma.to_inv.p))
 		return count;
 
@@ -58,7 +58,7 @@ int ScriptApiNodemeta::nodemeta_inventory_AllowMove(
 	PCALL_RES(lua_pcall(L, 7, 1, error_handler));
 	if (!lua_isnumber(L, -1))
 		throw LuaError("allow_metadata_inventory_move should"
-				" return a number, guilty node: " + nodename);
+				" return a number. node=" + nodename);
 	int num = luaL_checkinteger(L, -1);
 	lua_pop(L, 2); // Pop integer and error handler
 	return num;
@@ -81,7 +81,7 @@ int ScriptApiNodemeta::nodemeta_inventory_AllowPut(
 		return 0;
 
 	// Push callback function on stack
-	std::string nodename = ndef->get(node).name;
+	const auto &nodename = ndef->get(node).name;
 	if (!getItemCallback(nodename.c_str(), "allow_metadata_inventory_put", &ma.to_inv.p))
 		return stack.count;
 
@@ -94,7 +94,7 @@ int ScriptApiNodemeta::nodemeta_inventory_AllowPut(
 	PCALL_RES(lua_pcall(L, 5, 1, error_handler));
 	if(!lua_isnumber(L, -1))
 		throw LuaError("allow_metadata_inventory_put should"
-				" return a number, guilty node: " + nodename);
+				" return a number. node=" + nodename);
 	int num = luaL_checkinteger(L, -1);
 	lua_pop(L, 2); // Pop integer and error handler
 	return num;
@@ -117,7 +117,7 @@ int ScriptApiNodemeta::nodemeta_inventory_AllowTake(
 		return 0;
 
 	// Push callback function on stack
-	std::string nodename = ndef->get(node).name;
+	const auto &nodename = ndef->get(node).name;
 	if (!getItemCallback(nodename.c_str(), "allow_metadata_inventory_take", &ma.from_inv.p))
 		return stack.count;
 
@@ -130,7 +130,7 @@ int ScriptApiNodemeta::nodemeta_inventory_AllowTake(
 	PCALL_RES(lua_pcall(L, 5, 1, error_handler));
 	if (!lua_isnumber(L, -1))
 		throw LuaError("allow_metadata_inventory_take should"
-				" return a number, guilty node: " + nodename);
+				" return a number. node=" + nodename);
 	int num = luaL_checkinteger(L, -1);
 	lua_pop(L, 2); // Pop integer and error handler
 	return num;
@@ -153,7 +153,7 @@ void ScriptApiNodemeta::nodemeta_inventory_OnMove(
 		return;
 
 	// Push callback function on stack
-	std::string nodename = ndef->get(node).name;
+	const auto &nodename = ndef->get(node).name;
 	if (!getItemCallback(nodename.c_str(), "on_metadata_inventory_move", &ma.from_inv.p))
 		return;
 
@@ -186,7 +186,7 @@ void ScriptApiNodemeta::nodemeta_inventory_OnPut(
 		return;
 
 	// Push callback function on stack
-	std::string nodename = ndef->get(node).name;
+	const auto &nodename = ndef->get(node).name;
 	if (!getItemCallback(nodename.c_str(), "on_metadata_inventory_put", &ma.to_inv.p))
 		return;
 
@@ -217,7 +217,7 @@ void ScriptApiNodemeta::nodemeta_inventory_OnTake(
 		return;
 
 	// Push callback function on stack
-	std::string nodename = ndef->get(node).name;
+	const auto &nodename = ndef->get(node).name;
 	if (!getItemCallback(nodename.c_str(), "on_metadata_inventory_take", &ma.from_inv.p))
 		return;
 
diff --git a/src/script/cpp_api/s_player.cpp b/src/script/cpp_api/s_player.cpp
index d3e6138dc..22b24f363 100644
--- a/src/script/cpp_api/s_player.cpp
+++ b/src/script/cpp_api/s_player.cpp
@@ -60,7 +60,7 @@ bool ScriptApiPlayer::on_punchplayer(ServerActiveObject *player,
 		float time_from_last_punch,
 		const ToolCapabilities *toolcap,
 		v3f dir,
-		s16 damage)
+		s32 damage)
 {
 	SCRIPTAPI_PRECHECKHEADER
 	// Get core.registered_on_punchplayers
diff --git a/src/script/cpp_api/s_player.h b/src/script/cpp_api/s_player.h
index c0f141862..e866aee46 100644
--- a/src/script/cpp_api/s_player.h
+++ b/src/script/cpp_api/s_player.h
@@ -46,7 +46,7 @@ public:
 	void on_cheat(ServerActiveObject *player, const std::string &cheat_type);
 	bool on_punchplayer(ServerActiveObject *player, ServerActiveObject *hitter,
 			float time_from_last_punch, const ToolCapabilities *toolcap,
-			v3f dir, s16 damage);
+			v3f dir, s32 damage);
 	void on_rightclickplayer(ServerActiveObject *player, ServerActiveObject *clicker);
 	s32 on_player_hpchange(ServerActiveObject *player, s32 hp_change,
 			const PlayerHPChangeReason &reason);
diff --git a/src/script/cpp_api/s_security.cpp b/src/script/cpp_api/s_security.cpp
index 63058d7c3..a6c5114b2 100644
--- a/src/script/cpp_api/s_security.cpp
+++ b/src/script/cpp_api/s_security.cpp
@@ -18,7 +18,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 */
 
 #include "cpp_api/s_security.h"
-
+#include "lua_api/l_base.h"
 #include "filesys.h"
 #include "porting.h"
 #include "server.h"
@@ -27,6 +27,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 
 #include <cerrno>
 #include <string>
+#include <algorithm>
 #include <iostream>
 
 
@@ -45,6 +46,21 @@ static inline void copy_safe(lua_State *L, const char *list[], unsigned len, int
 	}
 }
 
+static void shallow_copy_table(lua_State *L, int from=-2, int to=-1)
+{
+	if (from < 0) from = lua_gettop(L) + from + 1;
+	if (to   < 0) to   = lua_gettop(L) + to   + 1;
+	lua_pushnil(L);
+	while (lua_next(L, from) != 0) {
+		assert(lua_type(L, -1) != LUA_TTABLE);
+		// duplicate key and value for lua_rawset
+		lua_pushvalue(L, -2);
+		lua_pushvalue(L, -2);
+		lua_rawset(L, to);
+		lua_pop(L, 1);
+	}
+}
+
 // Pushes the original version of a library function on the stack, from the old version
 static inline void push_original(lua_State *L, const char *lib, const char *func)
 {
@@ -83,11 +99,15 @@ void ScriptApiSecurity::initializeSecurity()
 		"unpack",
 		"_VERSION",
 		"xpcall",
-		// Completely safe libraries
+	};
+	static const char *whitelist_tables[] = {
+		// These libraries are completely safe BUT we need to duplicate their table
+		// to ensure the sandbox can't affect the insecure env
 		"coroutine",
 		"string",
 		"table",
 		"math",
+		"bit"
 	};
 	static const char *io_whitelist[] = {
 		"close",
@@ -101,21 +121,17 @@ void ScriptApiSecurity::initializeSecurity()
 		"date",
 		"difftime",
 		"getenv",
-		"setlocale",
 		"time",
-		"tmpname",
 	};
 	static const char *debug_whitelist[] = {
 		"gethook",
 		"traceback",
 		"getinfo",
 		"getmetatable",
-		"setupvalue",
 		"setmetatable",
 		"upvalueid",
 		"sethook",
 		"debug",
-		"setlocal",
 	};
 	static const char *package_whitelist[] = {
 		"config",
@@ -167,6 +183,17 @@ void ScriptApiSecurity::initializeSecurity()
 	lua_pop(L, 1);
 
 
+	// Copy safe libraries
+	for (const char *libname : whitelist_tables) {
+		lua_getfield(L, old_globals, libname);
+		lua_newtable(L);
+		shallow_copy_table(L);
+
+		lua_setglobal(L, libname);
+		lua_pop(L, 1);
+	}
+
+
 	// Copy safe IO functions
 	lua_getfield(L, old_globals, "io");
 	lua_newtable(L);
@@ -190,6 +217,7 @@ void ScriptApiSecurity::initializeSecurity()
 	// And replace unsafe ones
 	SECURE_API(os, remove);
 	SECURE_API(os, rename);
+	SECURE_API(os, setlocale);
 
 	lua_setglobal(L, "os");
 	lua_pop(L, 1);  // Pop old OS
@@ -221,7 +249,25 @@ void ScriptApiSecurity::initializeSecurity()
 	lua_pop(L, 1);  // Pop old jit
 #endif
 
+	// Get rid of 'core' in the old globals, we don't want anyone thinking it's
+	// safe or even usable.
+	lua_pushnil(L);
+	lua_setfield(L, old_globals, "core");
+
 	lua_pop(L, 1); // Pop globals_backup
+
+
+	/*
+	 * In addition to copying the tables in whitelist_tables, we also need to
+	 * replace the string metatable. Otherwise old_globals.string would
+	 * be accessible via getmetatable("").__index from inside the sandbox.
+	 */
+	lua_pushliteral(L, "");
+	lua_newtable(L);
+	lua_getglobal(L, "string");
+	lua_setfield(L, -2, "__index");
+	lua_setmetatable(L, -2);
+	lua_pop(L, 1); // Pop empty string
 }
 
 void ScriptApiSecurity::initializeSecurityClient()
@@ -243,7 +289,7 @@ void ScriptApiSecurity::initializeSecurityClient()
 		"rawset",
 		"select",
 		"setfenv",
-		// getmetatable can be used to escape the sandbox
+		// getmetatable can be used to escape the sandbox <- ???
 		"setmetatable",
 		"tonumber",
 		"tostring",
@@ -256,6 +302,7 @@ void ScriptApiSecurity::initializeSecurityClient()
 		"string",
 		"table",
 		"math",
+		"bit",
 	};
 	static const char *os_whitelist[] = {
 		"clock",
@@ -264,7 +311,7 @@ void ScriptApiSecurity::initializeSecurityClient()
 		"time"
 	};
 	static const char *debug_whitelist[] = {
-		"getinfo",
+		"getinfo", // used by builtin and unset before mods load
 		"traceback"
 	};
 
@@ -496,15 +543,8 @@ bool ScriptApiSecurity::checkPath(lua_State *L, const char *path,
 	if (!removed.empty())
 		abs_path += DIR_DELIM + removed;
 
-	// Get server from registry
-	lua_rawgeti(L, LUA_REGISTRYINDEX, CUSTOM_RIDX_SCRIPTAPI);
-	ScriptApiBase *script;
-#if INDIRECT_SCRIPTAPI_RIDX
-	script = (ScriptApiBase *) *(void**)(lua_touserdata(L, -1));
-#else
-	script = (ScriptApiBase *) lua_touserdata(L, -1);
-#endif
-	lua_pop(L, 1);
+	// Get gamedef from registry
+	ScriptApiBase *script = ModApiBase::getScriptApiBase(L);
 	const IGameDef *gamedef = script->getGameDef();
 	if (!gamedef)
 		return false;
@@ -569,6 +609,38 @@ bool ScriptApiSecurity::checkPath(lua_State *L, const char *path,
 	return false;
 }
 
+bool ScriptApiSecurity::checkWhitelisted(lua_State *L, const std::string &setting)
+{
+	assert(str_starts_with(setting, "secure."));
+
+	// We have to make sure that this function is being called directly by
+	// a mod, otherwise a malicious mod could override this function and
+	// steal its return value.
+	lua_Debug info;
+
+	// Make sure there's only one item below this function on the stack...
+	if (lua_getstack(L, 2, &info))
+		return false;
+	FATAL_ERROR_IF(!lua_getstack(L, 1, &info), "lua_getstack() failed");
+	FATAL_ERROR_IF(!lua_getinfo(L, "S", &info), "lua_getinfo() failed");
+
+	// ...and that that item is the main file scope.
+	if (strcmp(info.what, "main") != 0)
+		return false;
+
+	// Mod must be listed in secure.http_mods or secure.trusted_mods
+	lua_rawgeti(L, LUA_REGISTRYINDEX, CUSTOM_RIDX_CURRENT_MOD_NAME);
+	if (!lua_isstring(L, -1))
+		return false;
+	std::string mod_name = readParam<std::string>(L, -1);
+
+	std::string value = g_settings->get(setting);
+	value.erase(std::remove(value.begin(), value.end(), ' '), value.end());
+	auto mod_list = str_split(value, ',');
+
+	return CONTAINS(mod_list, mod_name);
+}
+
 
 int ScriptApiSecurity::sl_g_dofile(lua_State *L)
 {
@@ -627,13 +699,7 @@ int ScriptApiSecurity::sl_g_load(lua_State *L)
 int ScriptApiSecurity::sl_g_loadfile(lua_State *L)
 {
 #ifndef SERVER
-	lua_rawgeti(L, LUA_REGISTRYINDEX, CUSTOM_RIDX_SCRIPTAPI);
-#if INDIRECT_SCRIPTAPI_RIDX
-	ScriptApiBase *script = (ScriptApiBase *) *(void**)(lua_touserdata(L, -1));
-#else
-	ScriptApiBase *script = (ScriptApiBase *) lua_touserdata(L, -1);
-#endif
-	lua_pop(L, 1);
+	ScriptApiBase *script = ModApiBase::getScriptApiBase(L);
 
 	// Client implementation
 	if (script->getType() == ScriptingType::Client) {
@@ -806,3 +872,20 @@ int ScriptApiSecurity::sl_os_remove(lua_State *L)
 	return 2;
 }
 
+
+int ScriptApiSecurity::sl_os_setlocale(lua_State *L)
+{
+	const bool cat = lua_gettop(L) > 1;
+	// Don't allow changes
+	if (!lua_isnoneornil(L, 1)) {
+		lua_pushnil(L);
+		return 1;
+	}
+
+	push_original(L, "os", "setlocale");
+	lua_pushnil(L);
+	if (cat)
+		lua_pushvalue(L, 2);
+	lua_call(L, cat ? 2 : 1, 1);
+	return 1;
+}
diff --git a/src/script/cpp_api/s_security.h b/src/script/cpp_api/s_security.h
index 73e763548..880ce1638 100644
--- a/src/script/cpp_api/s_security.h
+++ b/src/script/cpp_api/s_security.h
@@ -40,11 +40,6 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 class ScriptApiSecurity : virtual public ScriptApiBase
 {
 public:
-	int getThread(lua_State *L);
-	// creates an empty Lua environment
-	void createEmptyEnv(lua_State *L);
-	// sets the enviroment to the table thats on top of the stack
-	void setLuaEnv(lua_State *L, int thread);
 	// Sets up security on the ScriptApi's Lua state
 	void initializeSecurity();
 	void initializeSecurityClient();
@@ -57,8 +52,17 @@ public:
 	// Checks if mods are allowed to read (and optionally write) to the path
 	static bool checkPath(lua_State *L, const char *path, bool write_required,
 			bool *write_allowed=NULL);
+	// Check if mod is whitelisted in the given setting
+	// This additionally checks that the mod's main file scope is executing.
+	static bool checkWhitelisted(lua_State *L, const std::string &setting);
 
 private:
+	int getThread(lua_State *L);
+	// sets the enviroment to the table thats on top of the stack
+	void setLuaEnv(lua_State *L, int thread);
+	// creates an empty Lua environment
+	void createEmptyEnv(lua_State *L);
+
 	// Syntax: "sl_" <Library name or 'g' (global)> '_' <Function name>
 	// (sl stands for Secure Lua)
 
@@ -75,4 +79,5 @@ private:
 
 	static int sl_os_rename(lua_State *L);
 	static int sl_os_remove(lua_State *L);
+	static int sl_os_setlocale(lua_State *L);
 };
diff --git a/src/script/cpp_api/s_server.cpp b/src/script/cpp_api/s_server.cpp
index 96cb28b28..c255b0c71 100644
--- a/src/script/cpp_api/s_server.cpp
+++ b/src/script/cpp_api/s_server.cpp
@@ -20,6 +20,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "cpp_api/s_server.h"
 #include "cpp_api/s_internal.h"
 #include "common/c_converter.h"
+#include "util/numeric.h" // myrand
 
 bool ScriptApiServer::getAuth(const std::string &playername,
 		std::string *dst_password,
@@ -196,3 +197,66 @@ std::string ScriptApiServer::formatChatMessage(const std::string &name,
 
 	return ret;
 }
+
+u32 ScriptApiServer::allocateDynamicMediaCallback(lua_State *L, int f_idx)
+{
+	if (f_idx < 0)
+		f_idx = lua_gettop(L) + f_idx + 1;
+
+	lua_getglobal(L, "core");
+	lua_getfield(L, -1, "dynamic_media_callbacks");
+	luaL_checktype(L, -1, LUA_TTABLE);
+
+	// Find a randomly generated token that doesn't exist yet
+	int tries = 100;
+	u32 token;
+	while (1) {
+		token = myrand();
+		lua_rawgeti(L, -2, token);
+		bool is_free = lua_isnil(L, -1);
+		lua_pop(L, 1);
+		if (is_free)
+			break;
+		if (--tries < 0)
+			FATAL_ERROR("Ran out of callbacks IDs?!");
+	}
+
+	// core.dynamic_media_callbacks[token] = callback_func
+	lua_pushvalue(L, f_idx);
+	lua_rawseti(L, -2, token);
+
+	lua_pop(L, 2);
+
+	verbosestream << "allocateDynamicMediaCallback() = " << token << std::endl;
+	return token;
+}
+
+void ScriptApiServer::freeDynamicMediaCallback(u32 token)
+{
+	SCRIPTAPI_PRECHECKHEADER
+
+	verbosestream << "freeDynamicMediaCallback(" << token << ")" << std::endl;
+
+	// core.dynamic_media_callbacks[token] = nil
+	lua_getglobal(L, "core");
+	lua_getfield(L, -1, "dynamic_media_callbacks");
+	luaL_checktype(L, -1, LUA_TTABLE);
+	lua_pushnil(L);
+	lua_rawseti(L, -2, token);
+	lua_pop(L, 2);
+}
+
+void ScriptApiServer::on_dynamic_media_added(u32 token, const char *playername)
+{
+	SCRIPTAPI_PRECHECKHEADER
+
+	int error_handler = PUSH_ERROR_HANDLER(L);
+	lua_getglobal(L, "core");
+	lua_getfield(L, -1, "dynamic_media_callbacks");
+	luaL_checktype(L, -1, LUA_TTABLE);
+	lua_rawgeti(L, -1, token);
+	luaL_checktype(L, -1, LUA_TFUNCTION);
+
+	lua_pushstring(L, playername);
+	PCALL_RES(lua_pcall(L, 1, 0, error_handler));
+}
diff --git a/src/script/cpp_api/s_server.h b/src/script/cpp_api/s_server.h
index d8639cba7..58c8c0e48 100644
--- a/src/script/cpp_api/s_server.h
+++ b/src/script/cpp_api/s_server.h
@@ -49,6 +49,12 @@ public:
 		const std::string &password);
 	bool setPassword(const std::string &playername,
 		const std::string &password);
+
+	/* dynamic media handling */
+	static u32 allocateDynamicMediaCallback(lua_State *L, int f_idx);
+	void freeDynamicMediaCallback(u32 token);
+	void on_dynamic_media_added(u32 token, const char *playername);
+
 private:
 	void getAuthHandler();
 	void readPrivileges(int index, std::set<std::string> &result);