daemon/ffimodule: ignore undefined layers on load

diff --git a/daemon/ffimodule.c b/daemon/ffimodule.c
index 92a2ea6632eaf3bf758a49c47ec947f87e4d56e9..040d5ee87bd2282d5de6813517a5016f29dddb09 100644 (file)
--- a/daemon/ffimodule.c
+++ b/daemon/ffimodule.c
@@ -178,6 +178,14 @@ static int l_ffi_layer_fail(knot_layer_t *ctx, knot_pkt_t *pkt)
        return l_ffi_call(L, 3);
 }
 
+/** Conditionally register layer trampoline */
+#define LAYER_REGISTER(L, api, name) do { \
+       lua_getfield((L), -1, "layer"); \
+       lua_getfield((L), -1, #name); \
+       if (!lua_isnil((L), -1)) (api)->name = l_ffi_layer_ ## name; \
+       lua_pop((L), 2); \
+} while(0)
+
 /** @internal Retrieve C layer api wrapper. */
 static const knot_layer_api_t* l_ffi_layer(struct kr_module *module)
 {
@@ -190,12 +198,13 @@ static const knot_layer_api_t* l_ffi_layer(struct kr_module *module)
                /* Fabricate layer API wrapping the Lua functions */
                api = malloc(sizeof(*api));
                if (api) {
-                       api->begin = l_ffi_layer_begin;
-                       api->finish = l_ffi_layer_finish;
-                       api->consume = l_ffi_layer_consume;
-                       api->produce = l_ffi_layer_produce;
-                       api->reset = l_ffi_layer_reset;
-                       api->fail = l_ffi_layer_fail;
+                       memset(api, 0, sizeof(*api));
+                       LAYER_REGISTER(L, api, begin);
+                       LAYER_REGISTER(L, api, finish);
+                       LAYER_REGISTER(L, api, consume);
+                       LAYER_REGISTER(L, api, produce);
+                       LAYER_REGISTER(L, api, reset);
+                       LAYER_REGISTER(L, api, fail);
                        api->data = module;
                }
                /* Store the api in the registry. */
@@ -206,6 +215,7 @@ static const knot_layer_api_t* l_ffi_layer(struct kr_module *module)
        return api;
 }
 
+#undef LAYER_REGISTER
 #undef LAYER_FFI_CALL
 
 /** @internal Helper macro for function presence check. */
@@ -213,7 +223,7 @@ static const knot_layer_api_t* l_ffi_layer(struct kr_module *module)
        lua_getfield((L), -1, (name)); \
        if (!lua_isnil((L), -1)) { attr = cb; } \
        lua_pop((L), 1); \
-       } while (0)
+} while (0)
 
 int ffimodule_register_lua(struct engine *engine, struct kr_module *module, const char *name)
 {
@@ -238,7 +248,10 @@ int ffimodule_register_lua(struct engine *engine, struct kr_module *module, cons
        module->data = (void *)(intptr_t)luaL_ref(L, LUA_REGISTRYINDEX);
        module->lib = L;
        lua_pop(L, 1); /* Clear the module global */
-       return module->init(module);
+       if (module->init) {
+               return module->init(module);
+       }
+       return kr_ok();
 }
 
 #undef REGISTER_FFI_CALL
\ No newline at end of file