ladybird/Kernel/Devices/ZeroDevice.cpp
Liav A f5de4f24b2 Kernel/Devices: Defer creation of SysFS component after the constructor
Instead of doing so in the constructor, let's do immediately after the
constructor, so we can safely pass a reference of a Device, so the
SysFSDeviceComponent constructor can use that object to identify whether
it's a block device or a character device.
This allows to us to not hold a device in SysFSDeviceComponent with a
RefPtr.
Also, we also call the before_removing method in both SlavePTY::unref
and File::unref, so because Device has that method being overrided, it
can ensure the device is removed always cleanly.
2021-09-11 11:41:14 +02:00

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C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/Memory.h>
#include <Kernel/Devices/ZeroDevice.h>
#include <Kernel/Sections.h>
namespace Kernel {
UNMAP_AFTER_INIT NonnullRefPtr<ZeroDevice> ZeroDevice::must_create()
{
auto zero_device_or_error = try_create_device<ZeroDevice>();
// FIXME: Find a way to propagate errors
VERIFY(!zero_device_or_error.is_error());
return zero_device_or_error.release_value();
}
UNMAP_AFTER_INIT ZeroDevice::ZeroDevice()
: CharacterDevice(1, 5)
{
}
UNMAP_AFTER_INIT ZeroDevice::~ZeroDevice()
{
}
bool ZeroDevice::can_read(const OpenFileDescription&, size_t) const
{
return true;
}
KResultOr<size_t> ZeroDevice::read(OpenFileDescription&, u64, UserOrKernelBuffer& buffer, size_t size)
{
TRY(buffer.memset(0, size));
return size;
}
KResultOr<size_t> ZeroDevice::write(OpenFileDescription&, u64, const UserOrKernelBuffer&, size_t size)
{
return size;
}
}