make c, cpp and rust plugins as well as their builders (thank you claude). Also add support for multi lang plugins so that we can actually fucking unload them unlike shitty golang (issue has been opened since 2015 and there is no due date for the issue...)

Overlord-Client/cmd/agent/plugins/loader_windows.go

@@ -43,12 +43,29 @@ func loadNativePlugin(data []byte) (NativePlugin, error) {
 
 	setCallback, _ := mm.GetExport("PluginSetCallback")
 
+	runtime := "go"
+	if getRuntimeAddr, err := mm.GetExport("PluginGetRuntime"); err == nil {
+		ret, _, _ := syscall.SyscallN(getRuntimeAddr)
+		if ret != 0 {
+			var buf [32]byte
+			for i := range buf {
+				b := *(*byte)(unsafe.Pointer(ret + uintptr(i)))
+				if b == 0 {
+					runtime = string(buf[:i])
+					break
+				}
+				buf[i] = b
+			}
+		}
+	}
+
 	dp := &dllPlugin{
 		mem:             mm,
 		onLoadAddr:      onLoad,
 		onEventAddr:     onEvent,
 		onUnloadAddr:    onUnload,
 		setCallbackAddr: setCallback,
+		pluginRuntime:   runtime,
 	}
 	return dp, nil
 }
@@ -60,6 +77,7 @@ type dllPlugin struct {
 	onUnloadAddr    uintptr
 	setCallbackAddr uintptr
 	callbackHandle  uintptr // prevent GC of the callback closure
+	pluginRuntime   string  // "go", "c", "cpp", etc.
 	mu              sync.Mutex
 }
 
@@ -130,8 +148,17 @@ func (p *dllPlugin) Unload() {
 
 func (p *dllPlugin) Close() error {
 	p.Unload()
-	// https://github.com/golang/go/issues/11100 as of right now you can't
-	// unload a go c-shared DLL safely
-	p.mem = nil
+	if p.pluginRuntime != "go" {
+		if p.mem != nil {
+			p.mem.Free()
+			p.mem = nil
+		}
+	} else {
+		p.mem = nil
+	}
 	return nil
 }
+
+func (p *dllPlugin) Runtime() string {
+	return p.pluginRuntime
+}