create handle function

[vxcall]

in init function,

• it needs opening device handle by NtOpenFile

// L"\\Device\\echo", GENERIC_READ | GENERIC_WRITE
auto retrieve_device_handle(std::wstring device_name, ACCESS_MASK access_mask) -> PHANDLE
{
    NTSTATUS status;
    HANDLE device_handle;
    OBJECT_ATTRIBUTES obj_attr;
    UNICODE_STRING uni_device_name;
    IO_STATUS_BLOCK io_status_block;

    RtlInitUnicodeString(&uni_device_name, device_name);

    InitializeObjectAttributes(&obj_attr, &uni_device_name,
        OBJ_CASE_INSENSITIVE | OBJ_KERNEL_HANDLE, NULL, NULL);

    ACCESS_MASK access_mask = ;
    ULONG share_access = 0;
    ULONG open_options = 0;

    status = NtOpenFile(&device_handle,
                        access_mask,
                        &obj_attr,
                        &io_status_block,
                        share_access,
                        open_options);

    if (!NT_SUCCESS(status)) {
        std::cerr << "Failed to open handle. Status code: " << std::hex << status << std::endl;
        return nullptr;
    }
    // This handle has to be closed with CloseHandle(device_handle);
    return device_handle;
}