ladybird/Kernel/Devices/NullDevice.cpp
Gunnar Beutner 1ce32ef675 Kernel: Let the user read/write more than one page from/to dev files
Previously reads and writes to /dev/zero, /dev/full, /dev/null and
/dev/random were limited to 4096 bytes.

This removes that restriction so that users can enjoy more zero bytes
in their buffers.
2021-05-27 09:30:19 +02:00

49 lines
845 B
C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include "NullDevice.h"
#include <AK/Singleton.h>
#include <AK/StdLibExtras.h>
namespace Kernel {
static AK::Singleton<NullDevice> s_the;
UNMAP_AFTER_INIT void NullDevice::initialize()
{
s_the.ensure_instance();
}
NullDevice& NullDevice::the()
{
return *s_the;
}
UNMAP_AFTER_INIT NullDevice::NullDevice()
: CharacterDevice(1, 3)
{
}
UNMAP_AFTER_INIT NullDevice::~NullDevice()
{
}
bool NullDevice::can_read(const FileDescription&, size_t) const
{
return true;
}
KResultOr<size_t> NullDevice::read(FileDescription&, u64, UserOrKernelBuffer&, size_t)
{
return 0;
}
KResultOr<size_t> NullDevice::write(FileDescription&, u64, const UserOrKernelBuffer&, size_t buffer_size)
{
return buffer_size;
}
}