ladybird/Kernel/Devices/ZeroDevice.cpp
Andreas Kling 19d3f8cab7 Kernel+LibC: Turn errno codes into a strongly typed enum
..and allow implicit creation of KResult and KResultOr from ErrnoCode.
This means that kernel functions that return those types can finally
do "return EINVAL;" and it will just work.

There's a handful of functions that still deal with signed integers
that should be converted to return KResults.
2021-01-20 23:20:02 +01:00

60 lines
2 KiB
C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "ZeroDevice.h"
#include <AK/Memory.h>
#include <AK/StdLibExtras.h>
namespace Kernel {
ZeroDevice::ZeroDevice()
: CharacterDevice(1, 5)
{
}
ZeroDevice::~ZeroDevice()
{
}
bool ZeroDevice::can_read(const FileDescription&, size_t) const
{
return true;
}
KResultOr<size_t> ZeroDevice::read(FileDescription&, size_t, UserOrKernelBuffer& buffer, size_t size)
{
ssize_t count = min(static_cast<size_t>(PAGE_SIZE), size);
if (!buffer.memset(0, count))
return EFAULT;
return count;
}
KResultOr<size_t> ZeroDevice::write(FileDescription&, size_t, const UserOrKernelBuffer&, size_t size)
{
return min(static_cast<size_t>(PAGE_SIZE), size);
}
}