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/*
* System Call getentropy(2)
* (C) 2017 Alexander Bluhm (genua GmbH)
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#include <botan/internal/getentropy.h>
#if defined(BOTAN_TARGET_OS_IS_OPENBSD) || defined(BOTAN_TARGET_OS_IS_FREEBSD)
#include <unistd.h>
#else
#include <sys/random.h>
#endif
namespace Botan {
/**
* Gather 256 bytes entropy from getentropy(2). Note that maximum
* buffer size is limited to 256 bytes. On OpenBSD this does neither
* block nor fail.
*/
size_t Getentropy::poll(RandomNumberGenerator& rng)
{
secure_vector<uint8_t> buf(256);
if(::getentropy(buf.data(), buf.size()) == 0)
{
rng.add_entropy(buf.data(), buf.size());
return buf.size() * 8;
}
return 0;
}
}