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/*
* 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 <Kernel/Devices/RandomDevice.h>
#include <Kernel/Random.h>
namespace Kernel {
UNMAP_AFTER_INIT RandomDevice::RandomDevice()
: CharacterDevice(1, 8)
{
}
UNMAP_AFTER_INIT RandomDevice::~RandomDevice()
{
}
bool RandomDevice::can_read(const FileDescription&, size_t) const
{
return true;
}
KResultOr<size_t> RandomDevice::read(FileDescription&, size_t, UserOrKernelBuffer& buffer, size_t size)
{
bool success = buffer.write_buffered<256>(size, [&](u8* data, size_t data_size) {
get_good_random_bytes(data, data_size);
return (ssize_t)data_size;
});
if (!success)
return EFAULT;
return size;
}
KResultOr<size_t> RandomDevice::write(FileDescription&, size_t, const UserOrKernelBuffer&, size_t size)
{
// FIXME: Use input for entropy? I guess that could be a neat feature?
return min(static_cast<size_t>(PAGE_SIZE), size);
}
}
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