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Serenity Operating System
1/*
2 * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
3 *
4 * SPDX-License-Identifier: BSD-2-Clause
5 */
6
7#include <AK/Singleton.h>
8#include <Kernel/Devices/DeviceManagement.h>
9#include <Kernel/Devices/NullDevice.h>
10#include <Kernel/Sections.h>
11
12namespace Kernel {
13
14UNMAP_AFTER_INIT NonnullLockRefPtr<NullDevice> NullDevice::must_initialize()
15{
16 auto null_device_or_error = DeviceManagement::try_create_device<NullDevice>();
17 // FIXME: Find a way to propagate errors
18 VERIFY(!null_device_or_error.is_error());
19 return null_device_or_error.release_value();
20}
21
22UNMAP_AFTER_INIT NullDevice::NullDevice()
23 : CharacterDevice(1, 3)
24{
25}
26
27UNMAP_AFTER_INIT NullDevice::~NullDevice() = default;
28
29bool NullDevice::can_read(OpenFileDescription const&, u64) const
30{
31 return true;
32}
33
34ErrorOr<size_t> NullDevice::read(OpenFileDescription&, u64, UserOrKernelBuffer&, size_t)
35{
36 return 0;
37}
38
39ErrorOr<size_t> NullDevice::write(OpenFileDescription&, u64, UserOrKernelBuffer const&, size_t buffer_size)
40{
41 return buffer_size;
42}
43
44}