serenity/Kernel/Syscalls/getrandom.cpp
2021-09-06 02:36:21 +02:00

34 lines
1,016 B
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<FlatPtr> Process::sys$getrandom(Userspace<void*> buffer, size_t buffer_size, [[maybe_unused]] unsigned flags)
{
VERIFY_NO_PROCESS_BIG_LOCK(this);
REQUIRE_PROMISE(stdio);
if (buffer_size > NumericLimits<ssize_t>::max())
return EINVAL;
auto data_buffer = UserOrKernelBuffer::for_user_buffer(buffer, buffer_size);
if (!data_buffer.has_value())
return EFAULT;
return TRY(data_buffer.value().write_buffered<1024>(buffer_size, [&](Bytes bytes) {
get_good_random_bytes(bytes);
return bytes.size();
}));
}
}