// protects from directory traversal
func safeJoin(baseDir, path string) string{
  return filepath.Join(baseDir, filepath.Join("/", path))
}



func getSyscallArg(v interface{}) uintptr {
	r := reflect.ValueOf(v)
	switch r.Kind(){
	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
		return uintptr(r.Int())
	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
		return uintptr(r.Uint())
	case reflect.Ptr, reflect.UnsafePointer, reflect.Slice:
		return r.Pointer()
	case reflect.String:
		b := []byte(r.String())
		b = append(b, 0)
		return reflect.ValueOf(b).Pointer()
		// TODO: add&test support Array and Struct
		//case reflect.Array:
		//	return r.Index(0).Addr()
	}
	// or panic?
	return 0

}


func getByte(addr uintptr) byte{
	return (*struct{b byte})(unsafe.Pointer(addr)).b
}

func setByte(addr uintptr, value byte){
	(*struct{b byte})(unsafe.Pointer(addr)).b = value
}