Add `minetest.get_game_info` and allow reading `game.conf` (#12989)

Co-authored-by: sfan5 <sfan5@live.de>

doc/lua_api.txt

@@ -4879,6 +4879,18 @@ Utilities
   or checking if a mod is enabled.
 * `minetest.get_modnames()`: returns a list of enabled mods, sorted alphabetically.
     * Does not include disabled mods, even if they are installed.
+* `minetest.get_game_info()`: returns a table containing information about the
+  current game. Note that other meta information (e.g. version/release number)
+  can be manually read from `game.conf` in the game's root directory.
+
+      {
+          id = string,
+          title = string,
+          author = string,
+          -- The root directory of the game
+          path = string,
+      }
+
 * `minetest.get_worldpath()`: returns e.g. `"/home/user/.minetest/world"`
     * Useful for storing custom data
 * `minetest.is_singleplayer()`

games/devtest/mods/unittests/misc.lua

@@ -103,3 +103,10 @@ local function test_compress()
 end
 unittests.register("test_compress", test_compress)
 
+local function test_game_info()
+	local info = minetest.get_game_info()
+	local game_conf = Settings(info.path .. "/game.conf")
+	assert(info.id == "devtest")
+	assert(info.title == game_conf:get("title"))
+end
+unittests.register("test_game_info", test_game_info)

src/gamedef.h

@@ -40,6 +40,7 @@ namespace irr { namespace scene {
 	class ISceneManager;
 }}
 
+struct SubgameSpec;
 struct ModSpec;
 /*
 	An interface for fetching game-global definitions like tool and
@@ -72,6 +73,7 @@ public:
 
 	virtual const std::vector<ModSpec> &getMods() const = 0;
 	virtual const ModSpec* getModSpec(const std::string &modname) const = 0;
+	virtual const SubgameSpec* getGameSpec() const { return nullptr; }
 	virtual std::string getWorldPath() const { return ""; }
 	virtual ModStorageDatabase *getModStorageDatabase() = 0;
 

src/script/cpp_api/s_security.cpp

@@ -579,6 +579,17 @@ bool ScriptApiSecurity::checkPath(lua_State *L, const char *path,
 	}
 	lua_pop(L, 1);  // Pop mod name
 
+	// Allow read-only access to game directory
+	if (!write_required) {
+		const SubgameSpec *game_spec = gamedef->getGameSpec();
+		if (game_spec && !game_spec->path.empty()) {
+			str = fs::AbsolutePath(game_spec->path);
+			if (!str.empty() && fs::PathStartsWith(abs_path, str)) {
+				return true;
+			}
+		}
+	}
+
 	// Allow read-only access to all mod directories
 	if (!write_required) {
 		const std::vector<ModSpec> &mods = gamedef->getMods();

src/script/lua_api/l_server.cpp

@@ -424,6 +424,20 @@ int ModApiServer::l_get_modnames(lua_State *L)
 	return 1;
 }
 
+// get_game_info()
+int ModApiServer::l_get_game_info(lua_State *L)
+{
+	NO_MAP_LOCK_REQUIRED;
+	const SubgameSpec *game_spec = getGameDef(L)->getGameSpec();
+	assert(game_spec);
+	lua_newtable(L);
+	setstringfield(L, -1, "id", game_spec->id);
+	setstringfield(L, -1, "title", game_spec->title);
+	setstringfield(L, -1, "author", game_spec->author);
+	setstringfield(L, -1, "path", game_spec->path);
+	return 1;
+}
+
 // get_worldpath()
 int ModApiServer::l_get_worldpath(lua_State *L)
 {
@@ -608,6 +622,7 @@ void ModApiServer::Initialize(lua_State *L, int top)
 	API_FCT(get_current_modname);
 	API_FCT(get_modpath);
 	API_FCT(get_modnames);
+	API_FCT(get_game_info);
 
 	API_FCT(print);
 
@@ -643,4 +658,5 @@ void ModApiServer::InitializeAsync(lua_State *L, int top)
 	API_FCT(get_current_modname);
 	API_FCT(get_modpath);
 	API_FCT(get_modnames);
+	API_FCT(get_game_info);
 }

src/script/lua_api/l_server.h

@@ -52,6 +52,9 @@ private:
 	// the returned list is sorted alphabetically for you
 	static int l_get_modnames(lua_State *L);
 
+	// get_game_info()
+	static int l_get_game_info(lua_State *L);
+
 	// print(text)
 	static int l_print(lua_State *L);
 

src/server.h

@@ -284,6 +284,7 @@ public:
 
 	virtual const std::vector<ModSpec> &getMods() const;
 	virtual const ModSpec* getModSpec(const std::string &modname) const;
+	virtual const SubgameSpec* getGameSpec() const { return &m_gamespec; }
 	static std::string getBuiltinLuaPath();
 	virtual std::string getWorldPath() const { return m_path_world; }