Allow running without a config file

Introduce AllowlistMode option to accomodate for this.
It can be disabled when using a config file too if you prefer so.

ExampleConfig.ini

@@ -5,6 +5,7 @@
 # GyroNormalizationFactor controls how quickly gyro drift is accounted for
 # Default value of 50 should be good in 99%+ of cases, but rarely one may want to tweak it
 [Linuxmotehook]
+AllowlistMode=true
 Port=26760
 Orientation=sideways-left
 SendButtons=false

README.md

@@ -18,6 +18,12 @@
 * Support for reporting IR as touch (potentially useful with dolphin)
 * Support for more Wiimote extensions - if requested
 
+## Configuration
+
+No configuration file is required to get started - just run without any arguments to expose all Wiimotes with default settings.
+However, you may want one for changing port, controller orientation, or something else.
+Check out [wiki](https://github.com/v1993/linuxmotehook2/wiki) for information on how to write a configuration file.
+
 ## Quick build guide
 
 ```bash
@@ -56,6 +62,3 @@ sudo apt-get install build-essential \
     meson
 ```
 
-## Configuration
-
-Check out [wiki](https://github.com/v1993/linuxmotehook2/wiki) for information on how to write configuration file.

src/Config.vala

@@ -28,7 +28,7 @@ namespace Linuxmotehook {
 		public int pro_controller_stick_calibration[8];
 
 		// TODO: initialize fields directly once initializing from arrays is fixed
-		// Also don't incherit from Object once that's done
+		// Also don't inherit from Object once that's done
 		construct {
 			gyro_calibration = {0, 0, 0};
 			orientation = NORMAL;
@@ -37,6 +37,11 @@ namespace Linuxmotehook {
 			classic_controller_stick_calibration = {0, 0, 25, 25, 0, 0, 25, 25};
 			pro_controller_stick_calibration = {0, 0, 1000, 1000, 0, 0, 1000, 1000};
 		}
+
+		public WiimoteConfig(Config global_conf) {
+			send_buttons = global_conf.send_buttons;
+			orientation = global_conf.orientation;
+		}
 	}
 
 	private int[] kfile_get_integer_list_checked(KeyFile kfile, string group, string key, size_t length) throws KeyFileError {
@@ -55,6 +60,15 @@ namespace Linuxmotehook {
 
 		private Gee.HashMap<uint64?, WiimoteConfig> wiimote_configs;
 
+		private bool allowlist_mode_ = false;
+		public bool allowlist_mode {
+			get { return allowlist_mode_; }
+			set {
+				allowlist_mode_ = value;
+				kfile.set_boolean(MAIN_GROUP, "AllowlistMode", value);
+			}
+		}
+
 		private uint16 port_ = 26760;
 		public uint16 port {
 			get { return port_; }
@@ -109,6 +123,9 @@ namespace Linuxmotehook {
 						case "Port":
 							port_ = (uint16)kfile.get_uint64(MAIN_GROUP, key);
 							break;
+						case "AllowlistMode":
+							allowlist_mode_ = kfile.get_boolean(MAIN_GROUP, key);
+							break;
 						case "Orientation":
 							var orient = kfile.get_string(MAIN_GROUP, key);
 							if (!Cemuhook.DeviceOrientation.try_parse(orient, out orientation_)) {
@@ -146,9 +163,7 @@ namespace Linuxmotehook {
 				assert(mac != Cemuhook.MAC_UNAVAILABLE);
 				assert((mac >> 48) == 0);
 
-				var conf = new WiimoteConfig();
-				conf.orientation = orientation;
-				conf.send_buttons = send_buttons;
+				var conf = new WiimoteConfig(this);
 
 				foreach (unowned string key in kfile.get_keys(group)) {
 					switch(key) {
@@ -189,7 +204,7 @@ namespace Linuxmotehook {
 				return wiimote_configs[mac];
 			}
 
-			return null;
+			return allowlist_mode ? null : new WiimoteConfig(this);
 		}
 
 		public void set_device_config(uint64 mac, WiimoteConfig conf)

src/main.vala

@@ -41,10 +41,10 @@ class LMApplication : Application {
 		};
 
 		add_main_option_entries(options);
-		set_option_context_parameter_string("config-file.ini");
+		set_option_context_parameter_string("[config-file.ini]");
 		set_option_context_summary("""Summary:
 Cemuhook UDP motion server for WiiMotes on Linux.""");
-		set_option_context_description("""I plan to soon make a handy GUI configuration tool for this program. Once done, I'll mention it here.
+		set_option_context_description("""I plan to eventually make a handy GUI configuration tool for this program. Once done, I'll mention it here.
 
 Copyright 2022 v1993 <v19930312@gmail.com>
 This program is free software: you can redistribute it and/or modify
@@ -54,31 +54,35 @@ the Free Software Foundation, either version 3 of the License, or
 	}
 
 	public override void activate() {
-		print("No config file specified - call with `--help' for usage information.\n");
-		Process.exit(1);
+		try {
+			hold();
+			server = new Server(config.port);
+		} catch(Error e) {
+			print("Failed to start server: %s\n", e.message);
+			return;
+		}
 	}
 
 	public override void open(File[] files, string hint) {
 		if (files.length != 1) {
-			print("Exactly single config file must be provided.");
+			print("Zero or one config files must be provided.\n");
 			Process.exit(1);
 		}
 
 		try {
+			config.allowlist_mode = true; // For compatibility with older versions
 			config.kfile.load_from_file(files[0].get_path(), NONE);
 			config.init_from_keyfile();
 		} catch (Error e) {
 			print("Error reading config file: %s\n", e.message);
 			return;
 		}
 
-		try {
-			hold();
-			server = new Server(config.port);
-		} catch(Error e) {
-			print("Failed to start server: %s\n", e.message);
-			return;
+		if (config.allowlist_mode) {
+			print("Allowlist mode enabled - only devices with a section in config will be served.\n");
 		}
+
+		activate();
 	}
 
 	public override int handle_local_options(VariantDict opt) {