//
|
// Copyright (c) 2018 Andrey Semashev
|
//
|
// Distributed under the Boost Software License, Version 1.0.
|
// (See accompanying file LICENSE_1_0.txt or copy at
|
// https://www.boost.org/LICENSE_1_0.txt)
|
//
|
// getrandom() capable platforms
|
//
|
|
#include <boost/config.hpp>
|
#include <boost/throw_exception.hpp>
|
#include <boost/predef/library/c/gnu.h>
|
#include <cerrno>
|
#include <cstddef>
|
|
#if !defined(BOOST_UUID_RANDOM_PROVIDER_GETRANDOM_IMPL_GETRANDOM)
|
#if BOOST_LIB_C_GNU >= BOOST_VERSION_NUMBER(2, 25, 0)
|
#define BOOST_UUID_RANDOM_PROVIDER_GETRANDOM_HAS_LIBC_WRAPPER
|
#elif defined(__has_include)
|
#if __has_include(<sys/random.h>)
|
#define BOOST_UUID_RANDOM_PROVIDER_GETRANDOM_HAS_LIBC_WRAPPER
|
#endif
|
#endif
|
#endif // !defined(BOOST_UUID_RANDOM_PROVIDER_GETRANDOM_IMPL_GETRANDOM)
|
|
#if defined(BOOST_UUID_RANDOM_PROVIDER_GETRANDOM_HAS_LIBC_WRAPPER)
|
#include <sys/random.h>
|
#else
|
#include <stddef.h> // ssize_t
|
#endif
|
|
namespace boost {
|
namespace uuids {
|
namespace detail {
|
|
class random_provider_base
|
{
|
public:
|
//! Obtain entropy and place it into a memory location
|
//! \param[in] buf the location to write entropy
|
//! \param[in] siz the number of bytes to acquire
|
void get_random_bytes(void *buf, std::size_t siz)
|
{
|
std::size_t offset = 0;
|
while (offset < siz)
|
{
|
ssize_t sz = get_random(static_cast< char* >(buf) + offset, siz - offset, 0u);
|
|
if (BOOST_UNLIKELY(sz < 0))
|
{
|
int err = errno;
|
if (err == EINTR)
|
continue;
|
BOOST_THROW_EXCEPTION(entropy_error(err, "getrandom"));
|
}
|
|
offset += sz;
|
}
|
}
|
|
private:
|
static ssize_t get_random(void *buf, std::size_t size, unsigned int flags)
|
{
|
#if defined(BOOST_UUID_RANDOM_PROVIDER_GETRANDOM_IMPL_GETRANDOM)
|
return BOOST_UUID_RANDOM_PROVIDER_GETRANDOM_IMPL_GETRANDOM(buf, size, flags);
|
#elif defined(BOOST_UUID_RANDOM_PROVIDER_GETRANDOM_HAS_LIBC_WRAPPER)
|
return ::getrandom(buf, size, flags);
|
#else
|
return ::syscall(SYS_getrandom, buf, size, flags);
|
#endif
|
}
|
};
|
|
} // detail
|
} // uuids
|
} // boost
|
