ladybird/Kernel/Syscalls/getrandom.cpp
Brian Gianforcaro bad6d50b86 Kernel: Use Process::require_promise() instead of REQUIRE_PROMISE()
This change lays the foundation for making the require_promise return
an error hand handling the process abort outside of the syscall
implementations, to avoid cases where we would leak resources.

It also has the advantage that it makes removes a gs pointer read
to look up the current thread, then process for every syscall. We
can instead go through the Process this pointer in most cases.
2021-12-29 18:08:15 +01:00

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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.
ErrorOr<FlatPtr> Process::sys$getrandom(Userspace<void*> buffer, size_t buffer_size, [[maybe_unused]] unsigned flags)
{
VERIFY_NO_PROCESS_BIG_LOCK(this);
require_promise(Pledge::stdio);
if (buffer_size > NumericLimits<ssize_t>::max())
return EINVAL;
auto data_buffer = TRY(UserOrKernelBuffer::for_user_buffer(buffer, buffer_size));
return TRY(data_buffer.write_buffered<1024>(buffer_size, [&](Bytes bytes) {
get_good_random_bytes(bytes);
return bytes.size();
}));
}
}