daemon: added basic bindings for modules, config and cache

daemon/bindings.c

+/*  Copyright (C) 2015 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "lib/cache.h"
+#include "daemon/bindings.h"
+
+/** @internal Compatibility wrapper for Lua 5.0 - 5.2 */
+#if LUA_VERSION_NUM < 502
+#define register_lib(L, name, lib) \
+	luaL_openlib((L), (name), (lib), 0)
+#else
+#define register_lib(L, name, lib) \
+	luaL_newlib((L), (lib))
+#endif
+
+/** List loaded modules */
+static int mod_list(lua_State *L)
+{
+	struct engine *engine = engine_luaget(L);
+	for (unsigned i = 0; i < engine->modules.len; ++i) {
+		struct kr_module *module = &engine->modules.at[i];
+		lua_pushstring(L, module->name);
+	}
+	return engine->modules.len;
+}
+
+/** Load module. */
+static int mod_load(lua_State *L)
+{
+	/* Check parameters */
+	int n = lua_gettop(L);
+	if (n != 1 || !lua_isstring(L, 1)) {
+		lua_pushstring(L, "expected module name");
+		lua_error(L);
+	}
+	/* Load engine module */
+	struct engine *engine = engine_luaget(L);
+	int ret = engine_register(engine, lua_tostring(L, 1));
+	if (ret != 0) {
+		lua_pushstring(L, kr_strerror(ret));
+		lua_error(L);
+	}
+	return 0;
+}
+
+/** Unload module. */
+static int mod_unload(lua_State *L)
+{
+	lua_pushstring(L, "not implemented");
+	lua_error(L);
+	return 0;
+}
+
+int lib_modules(lua_State *L)
+{
+	static const luaL_Reg lib[] = {
+		{ "list",   mod_list },
+		{ "load",   mod_load },
+		{ "unload", mod_unload },
+		{ NULL, NULL }
+	};
+
+	register_lib(L, "modules", lib);
+	return 1;
+}
+
+int lib_config(lua_State *L)
+{
+	return 0;
+}
+
+/** Open cache */
+static int cache_open(lua_State *L)
+{
+	/* Check parameters */
+	int n = lua_gettop(L);
+	if (n < 2) {
+		lua_pushstring(L, "expected (string path, int size)");
+		lua_error(L);
+	}
+
+	/* Open resolution context cache */
+	struct engine *engine = engine_luaget(L);
+	engine->resolver.cache = kr_cache_open(lua_tostring(L, 1), engine->pool, lua_tointeger(L, 2));
+	if (engine->resolver.cache == NULL) {
+		lua_pushstring(L, "invalid cache directory: ");
+		lua_pushstring(L, lua_tostring(L, 1));
+		lua_concat(L, 2);
+		lua_error(L);
+	}
+
+	lua_pushboolean(L, 1);
+	return 1;
+}
+
+static int cache_close(lua_State *L)
+{
+	struct engine *engine = engine_luaget(L);
+	if (engine->resolver.cache != NULL) {
+		kr_cache_close(engine->resolver.cache);
+		engine->resolver.cache = NULL;
+	}
+
+	return 0;
+}
+
+int lib_cache(lua_State *L)
+{
+	static const luaL_Reg lib[] = {
+		{ "open",   cache_open },
+		{ "close",  cache_close },
+		{ NULL, NULL }
+	};
+
+	register_lib(L, "cache", lib);
+	return 0;
+}
\ No newline at end of file

daemon/bindings.h

+/*  Copyright (C) 2015 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/**
+ * Bindings to engine services, see \a http://www.lua.org/manual/5.2/manual.html#luaL_newlib for the reference.
+ */
+#pragma once
+
+#include "daemon/engine.h"
+
+/**
+ * Load 'modules' package.
+ * @param  L scriptable
+ * @return   number of packages to load
+ */
+int lib_modules(lua_State *L);
+
+/**
+ * Load 'config' package.
+ * @param  L scriptable
+ * @return   number of packages to load
+ */
+int lib_config(lua_State *L);
+
+/**
+ * Load 'cache' package.
+ * @param  L scriptable
+ * @return   number of packages to load
+ */
+int lib_cache(lua_State *L);
\ No newline at end of file

daemon/daemon.mk

@@ -4,6 +4,7 @@ kresolved_SOURCES := \
 	daemon/tcp.c         \
 	daemon/engine.c      \
 	daemon/worker.c      \
+	daemon/bindings.c    \
 	daemon/main.c
 
 # Embed resources

daemon/main.c

@@ -25,6 +25,7 @@
 #include "daemon/udp.h"
 #include "daemon/tcp.h"
 #include "daemon/engine.h"
+#include "daemon/bindings.h"
 
 static void tty_read(uv_stream_t *stream, ssize_t nread, const uv_buf_t *buf)
 {
@@ -141,6 +142,10 @@ int main(int argc, char **argv)
 		return EXIT_FAILURE;
 	}
 
+	/* Load bindings */
+	engine_lualib(&engine, "modules", lib_modules);
+	engine_lualib(&engine, "config", lib_config);
+	engine_lualib(&engine, "cache",  lib_cache);
 
 	/* Create main worker. */
 	struct worker_ctx worker = {