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/* <!-- copyright */
/*
* aria2 - The high speed download utility
*
* Copyright (C) 2006 Tatsuhiro Tsujikawa
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
* In addition, as a special exception, the copyright holders give
* permission to link the code of portions of this program with the
* OpenSSL library under certain conditions as described in each
* individual source file, and distribute linked combinations
* including the two.
* You must obey the GNU General Public License in all respects
* for all of the code used other than OpenSSL. If you modify
* file(s) with this exception, you may extend this exception to your
* version of the file(s), but you are not obligated to do so. If you
* do not wish to do so, delete this exception statement from your
* version. If you delete this exception statement from all source
* files in the program, then also delete it here.
*/
/* copyright --> */
#include "SimpleRandomizer.h"
#include <sys/types.h>
#include <unistd.h>
#include <cstdlib>
#include <cassert>
#include <cstring>
#include "a2time.h"
#include "a2functional.h"
#include "LogFactory.h"
#include "fmt.h"
#ifdef HAVE_GETRANDOM_INTERFACE
#include <errno.h>
#include <linux/errno.h>
#include "getrandom_linux.h"
#endif
namespace aria2 {
std::unique_ptr<SimpleRandomizer> SimpleRandomizer::randomizer_;
const std::unique_ptr<SimpleRandomizer>& SimpleRandomizer::getInstance()
{
if (!randomizer_) {
randomizer_.reset(new SimpleRandomizer());
}
return randomizer_;
}
SimpleRandomizer::SimpleRandomizer()
{
#ifdef __MINGW32__
BOOL r = ::CryptAcquireContext(&provider_, 0, 0, PROV_RSA_FULL,
CRYPT_VERIFYCONTEXT | CRYPT_SILENT);
assert(r);
#endif
}
SimpleRandomizer::~SimpleRandomizer()
{
#ifdef __MINGW32__
CryptReleaseContext(provider_, 0);
#endif
}
long int SimpleRandomizer::getRandomNumber(long int to)
{
assert(to > 0);
return std::uniform_int_distribution<long int>(0, to - 1)(*this);
}
void SimpleRandomizer::getRandomBytes(unsigned char* buf, size_t len)
{
#ifdef __MINGW32__
BOOL r = CryptGenRandom(provider_, len, reinterpret_cast<BYTE*>(buf));
assert(r);
#else // ! __MINGW32__
#if defined(HAVE_GETRANDOM_INTERFACE)
static bool have_random_support = true;
if (have_random_support) {
auto rv = getrandom_linux(buf, len);
if (rv != -1
#ifdef ENOSYS
/* If the system does not know ENOSYS at this point, just leave the
* check out. If the call failed, we'll not take this branch at all
* and disable support below.
*/
||
errno != ENOSYS
#endif
) {
if (rv < -1) {
A2_LOG_ERROR(fmt("Failed to produce randomness: %d", errno));
}
// getrandom is not supposed to fail, ever, so, we want to assert here.
assert(rv >= 0 && (size_t)rv == len);
return;
}
have_random_support = false;
A2_LOG_INFO("Disabled getrandom support, because kernel does not "
"implement this feature (ENOSYS)");
}
// Fall through to generic implementation
#endif // defined(HAVE_GETRANDOM_INTERFACE)
auto ubuf = reinterpret_cast<result_type*>(buf);
size_t q = len / sizeof(result_type);
auto gen = std::uniform_int_distribution<result_type>();
for (; q > 0; --q, ++ubuf) {
*ubuf = gen(dev_);
}
const size_t r = len % sizeof(result_type);
auto last = gen(dev_);
memcpy(ubuf, &last, r);
#endif // ! __MINGW32__
}
} // namespace aria2
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