banan-os/kernel/kernel/Device/RandomDevice.cpp

33 lines
882 B
C++

#include <kernel/Device/DeviceNumbers.h>
#include <kernel/Device/RandomDevice.h>
#include <kernel/Random.h>
#include <sys/sysmacros.h>
namespace Kernel
{
BAN::ErrorOr<BAN::RefPtr<RandomDevice>> RandomDevice::create(mode_t mode, uid_t uid, gid_t gid)
{
static uint32_t minor = 0;
auto* result = new RandomDevice(mode, uid, gid, makedev(DeviceNumber::Random, minor++));
if (result == nullptr)
return BAN::Error::from_errno(ENOMEM);
return BAN::RefPtr<RandomDevice>::adopt(result);
}
BAN::ErrorOr<size_t> RandomDevice::read_impl(off_t, BAN::ByteSpan buffer)
{
size_t nwritten = 0;
while (nwritten < buffer.size())
{
const uint64_t random = Random::get_u64();
const size_t to_copy = BAN::Math::min(buffer.size() - nwritten, sizeof(random));
memcpy(buffer.data() + nwritten, &random, to_copy);
nwritten += to_copy;
}
return buffer.size();
}
}