ladybird/Kernel/Syscalls/getrandom.cpp
Andreas Kling e46343bf9a Kernel: Make UserOrKernelBuffer R/W helpers return KResultOr<size_t>
This makes error propagation less cumbersome (and also exposed some
places where we were not doing it.)
2021-05-13 23:28:40 +02:00

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C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <Kernel/Process.h>
#include <Kernel/Random.h>
#include <Kernel/UserOrKernelBuffer.h>
namespace Kernel {
// We don't use the flag yet, but we could use it for distinguishing
// random source like Linux, unlike the OpenBSD equivalent. However, if we
// do, we should be able of the caveats that Linux has dealt with.
KResultOr<size_t> Process::sys$getrandom(Userspace<void*> buffer, size_t buffer_size, [[maybe_unused]] unsigned flags)
{
REQUIRE_PROMISE(stdio);
if (buffer_size <= 0)
return EINVAL;
auto data_buffer = UserOrKernelBuffer::for_user_buffer(buffer, buffer_size);
if (!data_buffer.has_value())
return EFAULT;
return data_buffer.value().write_buffered<1024>(buffer_size, [&](u8* buffer, size_t buffer_bytes) {
get_good_random_bytes(buffer, buffer_bytes);
return buffer_bytes;
});
}
}