rotctl: actually quit when receiving the quit message

Since gpredict doesn't have a park button or anything, this will just
automatically park the antenna when the gpredict rotator controller
disconnects. This may or may not actually be a good idea. We will see.

src/Config.zig

@@ -92,6 +92,7 @@ pub fn validate(self: Config, err_writer: anytype) !void {
 rotctl: RotControlConfig = .{
     .listen_address = "127.0.0.1",
     .listen_port = 4533,
+    .autopark = false,
 },
 labjack: LabjackConfig = .{
     .device = .autodetect,
@@ -151,6 +152,7 @@ pub const MinMax = struct {
 const RotControlConfig = struct {
     listen_address: []const u8,
     listen_port: u16,
+    autopark: bool,
 };
 
 const LabjackConfig = struct {

src/RotCtl.zig

@@ -33,7 +33,7 @@ pub fn run(allocator: std.mem.Allocator) !void {
         .rotator = try YaesuController.init(allocator),
     };
 
-    while (true) {
+    while (interface.running) {
         const client = try server.accept();
         defer {
             log.info("disconnecting client", .{});
@@ -42,8 +42,6 @@ pub fn run(allocator: std.mem.Allocator) !void {
         }
 
         interface.writer = .{ .unbuffered_writer = client.stream.writer() };
-        interface.running = true;
-        defer interface.running = false;
 
         log.info("client connected from {}", .{client.address});
 
@@ -60,6 +58,11 @@ pub fn run(allocator: std.mem.Allocator) !void {
                 std.mem.trim(u8, fbs.getWritten(), &std.ascii.whitespace),
             ) catch break;
         }
+
+        // loop ended due to client disconnect
+        if (interface.running and config.rotctl.autopark) {
+            interface.rotator.startPark();
+        }
     }
 }