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//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include <__config>
#if defined(_LIBCPP_USING_WIN32_RANDOM)
// Must be defined before including stdlib.h to enable rand_s().
# define _CRT_RAND_S
#endif // defined(_LIBCPP_USING_WIN32_RANDOM)
#include <limits>
#include <random>
#include <system_error>
#if defined(__sun__)
# define rename solaris_headers_are_broken
#endif // defined(__sun__)
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#if defined(_LIBCPP_USING_GETENTROPY)
# include <sys/random.h>
#elif defined(_LIBCPP_USING_DEV_RANDOM)
# include <fcntl.h>
# include <unistd.h>
# if __has_include(<sys/ioctl.h>) && __has_include(<linux/random.h>)
# include <sys/ioctl.h>
# include <linux/random.h>
# endif
#elif defined(_LIBCPP_USING_NACL_RANDOM)
# include <nacl/nacl_random.h>
#elif defined(_LIBCPP_USING_FUCHSIA_CPRNG)
# include <zircon/syscalls.h>
#endif
_LIBCPP_BEGIN_NAMESPACE_STD
#if defined(_LIBCPP_USING_GETENTROPY)
random_device::random_device(const string& __token)
{
if (__token != "/dev/urandom")
__throw_system_error(ENOENT, ("random device not supported " + __token).c_str());
}
random_device::~random_device()
{
}
unsigned
random_device::operator()()
{
unsigned r;
size_t n = sizeof(r);
int err = getentropy(&r, n);
if (err)
__throw_system_error(errno, "random_device getentropy failed");
return r;
}
#elif defined(_LIBCPP_USING_ARC4_RANDOM)
random_device::random_device(const string&)
{
}
random_device::~random_device()
{
}
unsigned
random_device::operator()()
{
return arc4random();
}
#elif defined(_LIBCPP_USING_DEV_RANDOM)
random_device::random_device(const string& __token)
: __f_(open(__token.c_str(), O_RDONLY))
{
if (__f_ < 0)
__throw_system_error(errno, ("random_device failed to open " + __token).c_str());
}
random_device::~random_device()
{
close(__f_);
}
unsigned
random_device::operator()()
{
unsigned r;
size_t n = sizeof(r);
char* p = reinterpret_cast<char*>(&r);
while (n > 0)
{
ssize_t s = read(__f_, p, n);
if (s == 0)
__throw_system_error(ENODATA, "random_device got EOF");
if (s == -1)
{
if (errno != EINTR)
__throw_system_error(errno, "random_device got an unexpected error");
continue;
}
n -= static_cast<size_t>(s);
p += static_cast<size_t>(s);
}
return r;
}
#elif defined(_LIBCPP_USING_NACL_RANDOM)
random_device::random_device(const string& __token)
{
if (__token != "/dev/urandom")
__throw_system_error(ENOENT, ("random device not supported " + __token).c_str());
int error = nacl_secure_random_init();
if (error)
__throw_system_error(error, ("random device failed to open " + __token).c_str());
}
random_device::~random_device()
{
}
unsigned
random_device::operator()()
{
unsigned r;
size_t n = sizeof(r);
size_t bytes_written;
int error = nacl_secure_random(&r, n, &bytes_written);
if (error != 0)
__throw_system_error(error, "random_device failed getting bytes");
else if (bytes_written != n)
__throw_runtime_error("random_device failed to obtain enough bytes");
return r;
}
#elif defined(_LIBCPP_USING_WIN32_RANDOM)
random_device::random_device(const string& __token)
{
if (__token != "/dev/urandom")
__throw_system_error(ENOENT, ("random device not supported " + __token).c_str());
}
random_device::~random_device()
{
}
unsigned
random_device::operator()()
{
unsigned r;
errno_t err = rand_s(&r);
if (err)
__throw_system_error(err, "random_device rand_s failed.");
return r;
}
#elif defined(_LIBCPP_USING_FUCHSIA_CPRNG)
random_device::random_device(const string& __token) {
if (__token != "/dev/urandom")
__throw_system_error(ENOENT, ("random device not supported " + __token).c_str());
}
random_device::~random_device() {}
unsigned random_device::operator()() {
// Implicitly link against the vDSO system call ABI without
// requiring the final link to specify -lzircon explicitly when
// statically linking libc++.
# pragma comment(lib, "zircon")
// The system call cannot fail. It returns only when the bits are ready.
unsigned r;
_zx_cprng_draw(&r, sizeof(r));
return r;
}
#else
#error "Random device not implemented for this architecture"
#endif
double
random_device::entropy() const noexcept
{
#if defined(_LIBCPP_USING_DEV_RANDOM) && defined(RNDGETENTCNT)
int ent;
if (::ioctl(__f_, RNDGETENTCNT, &ent) < 0)
return 0;
if (ent < 0)
return 0;
if (ent > std::numeric_limits<result_type>::digits)
return std::numeric_limits<result_type>::digits;
return ent;
#elif defined(__OpenBSD__) || defined(_LIBCPP_USING_FUCHSIA_CPRNG)
return std::numeric_limits<result_type>::digits;
#else
return 0;
#endif
}
_LIBCPP_END_NAMESPACE_STD
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