jcs.org
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 <Kernel/Devices/DeviceManagement.h>
8#include <Kernel/Devices/RandomDevice.h>
9#include <Kernel/Random.h>
10#include <Kernel/Sections.h>
11
12namespace Kernel {
13
14UNMAP_AFTER_INIT NonnullLockRefPtr<RandomDevice> RandomDevice::must_create()
15{
16 auto random_device_or_error = DeviceManagement::try_create_device<RandomDevice>();
17 // FIXME: Find a way to propagate errors
18 VERIFY(!random_device_or_error.is_error());
19 return random_device_or_error.release_value();
20}
21
22UNMAP_AFTER_INIT RandomDevice::RandomDevice()
23 : CharacterDevice(1, 8)
24{
25}
26
27UNMAP_AFTER_INIT RandomDevice::~RandomDevice() = default;
28
29bool RandomDevice::can_read(OpenFileDescription const&, u64) const
30{
31 return true;
32}
33
34ErrorOr<size_t> RandomDevice::read(OpenFileDescription&, u64, UserOrKernelBuffer& buffer, size_t size)
35{
36 return buffer.write_buffered<256>(size, [&](Bytes bytes) {
37 get_good_random_bytes(bytes);
38 return bytes.size();
39 });
40}
41
42ErrorOr<size_t> RandomDevice::write(OpenFileDescription&, u64, UserOrKernelBuffer const&, size_t size)
43{
44 // FIXME: Use input for entropy? I guess that could be a neat feature?
45 return size;
46}
47
48}