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130 lines
3.6 KiB
C++
130 lines
3.6 KiB
C++
//===-------------------------- random.cpp --------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "libc/stdio/rand.h"
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#include "third_party/libcxx/__config"
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#include "third_party/libcxx/random"
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#include "third_party/libcxx/system_error"
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#include "third_party/libcxx/errno.h"
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#include "third_party/libcxx/stdio.h"
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#include "third_party/libcxx/stdlib.h"
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_LIBCPP_BEGIN_NAMESPACE_STD
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#if defined(_LIBCPP_USING_GETENTROPY)
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random_device::random_device(const string& __token) {
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if (__token != "/dev/urandom")
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__throw_system_error(ENOENT,
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("random device not supported " + __token).c_str());
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}
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random_device::~random_device() {}
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unsigned random_device::operator()() {
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unsigned r;
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size_t n = sizeof(r);
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int err = getentropy(&r, n);
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if (err)
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__throw_system_error(errno, "random_device getentropy failed");
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return r;
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}
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#elif defined(_LIBCPP_USING_ARC4_RANDOM)
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random_device::random_device(const string& __token) {
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if (__token != "/dev/urandom")
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__throw_system_error(ENOENT,
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("random device not supported " + __token).c_str());
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}
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random_device::~random_device() {}
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unsigned random_device::operator()() { return arc4random(); }
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#elif defined(_LIBCPP_USING_DEV_RANDOM)
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random_device::random_device(const string& __token)
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: __f_(open(__token.c_str(), O_RDONLY)) {
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if (__f_ < 0)
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__throw_system_error(errno,
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("random_device failed to open " + __token).c_str());
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}
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random_device::~random_device() { close(__f_); }
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unsigned random_device::operator()() {
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unsigned r;
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size_t n = sizeof(r);
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char* p = reinterpret_cast<char*>(&r);
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while (n > 0) {
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ssize_t s = read(__f_, p, n);
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if (s == 0)
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__throw_system_error(ENODATA, "random_device got EOF");
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if (s == -1) {
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if (errno != EINTR)
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__throw_system_error(errno, "random_device got an unexpected error");
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continue;
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}
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n -= static_cast<size_t>(s);
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p += static_cast<size_t>(s);
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}
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return r;
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}
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#elif defined(_LIBCPP_USING_NACL_RANDOM)
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random_device::random_device(const string& __token) {
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if (__token != "/dev/urandom")
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__throw_system_error(ENOENT,
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("random device not supported " + __token).c_str());
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int error = nacl_secure_random_init();
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if (error)
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__throw_system_error(error,
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("random device failed to open " + __token).c_str());
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}
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random_device::~random_device() {}
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unsigned random_device::operator()() {
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unsigned r;
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size_t n = sizeof(r);
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size_t bytes_written;
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int error = nacl_secure_random(&r, n, &bytes_written);
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if (error != 0)
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__throw_system_error(error, "random_device failed getting bytes");
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else if (bytes_written != n)
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__throw_runtime_error("random_device failed to obtain enough bytes");
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return r;
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}
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#elif defined(_LIBCPP_USING_WIN32_RANDOM)
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random_device::random_device(const string& __token) {
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if (__token != "/dev/urandom")
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__throw_system_error(ENOENT,
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("random device not supported " + __token).c_str());
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}
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random_device::~random_device() {}
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unsigned random_device::operator()() {
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unsigned r;
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errno_t err = rand_s(&r);
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if (err)
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__throw_system_error(err, "random_device rand_s failed.");
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return r;
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}
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#else
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#error "Random device not implemented for this architecture"
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#endif
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double random_device::entropy() const _NOEXCEPT { return 0; }
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_LIBCPP_END_NAMESPACE_STD
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