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edbdd06d71
This TODO has existed since the introduction of the Windows platform and has not been addressed. The implementation at this point is well tested in practice. Clean up the warning message and style and remove the warning.
137 lines
3.9 KiB
C++
137 lines
3.9 KiB
C++
//===--- Random.cpp -------------------------------------------------------===//
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//
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// This source file is part of the Swift.org open source project
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//
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// Copyright (c) 2014 - 2018 Apple Inc. and the Swift project authors
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// Licensed under Apache License v2.0 with Runtime Library Exception
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//
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// See https://swift.org/LICENSE.txt for license information
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// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
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//
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//===----------------------------------------------------------------------===//
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// swift_stdlib_random
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//
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// Should the implementation of this function add a new platform/change for a
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// platform, make sure to also update the documentation regarding platform
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// implementation of this function.
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// This can be found at: /docs/Random.md
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#if defined(_WIN32) && !defined(__CYGWIN__)
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#define WIN32_LEAN_AND_MEAN
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#define NOMINMAX
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#include <Windows.h>
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#include <Bcrypt.h>
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#pragma comment(lib, "bcrypt.lib")
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#elif !defined(__APPLE__)
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#include <errno.h>
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#include <fcntl.h>
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#if __has_include(<sys/random.h>)
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#include <sys/random.h>
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#endif
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#if __has_include(<sys/stat.h>)
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#include <sys/stat.h>
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#endif
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#if __has_include(<sys/syscall.h>)
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#include <sys/syscall.h>
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#endif
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#endif
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#if __has_include(<unistd.h>)
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#include <unistd.h>
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#endif
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#include <stdlib.h>
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#include "swift/shims/Random.h"
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#include "swift/Runtime/Debug.h"
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#include "swift/Threading/Mutex.h"
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#include <algorithm> // required for std::min
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using namespace swift;
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#if defined(__APPLE__)
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SWIFT_RUNTIME_STDLIB_API
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void swift_stdlib_random(void *buf, __swift_size_t nbytes) {
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arc4random_buf(buf, nbytes);
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}
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#elif defined(_WIN32) && !defined(__CYGWIN__)
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SWIFT_RUNTIME_STDLIB_API
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void swift_stdlib_random(void *buf, __swift_size_t nbytes) {
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while (nbytes > 0) {
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__swift_size_t actual_nbytes =
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std::min(nbytes, static_cast<__swift_size_t>(ULONG_MAX));
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NTSTATUS status = BCryptGenRandom(nullptr,
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static_cast<PUCHAR>(buf),
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static_cast<ULONG>(actual_nbytes),
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BCRYPT_USE_SYSTEM_PREFERRED_RNG);
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if (!BCRYPT_SUCCESS(status))
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fatalError(0, "Fatal error: BCryptGenRandom returned 0x%lX in '%s'\n",
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status, __func__);
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buf = static_cast<uint8_t *>(buf) + actual_nbytes;
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nbytes -= actual_nbytes;
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}
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}
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#else
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#undef WHILE_EINTR
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#define WHILE_EINTR(expression) ([&] () -> decltype(expression) { \
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decltype(expression) result = -1; \
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do { result = (expression); } while (result == -1 && errno == EINTR); \
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return result; \
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}())
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SWIFT_RUNTIME_STDLIB_API
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void swift_stdlib_random(void *buf, __swift_size_t nbytes) {
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while (nbytes > 0) {
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__swift_ssize_t actual_nbytes = -1;
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#if defined(__NR_getrandom)
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static const bool getrandom_available =
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!(syscall(__NR_getrandom, nullptr, 0, 0) == -1 && errno == ENOSYS);
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if (getrandom_available) {
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actual_nbytes = WHILE_EINTR(syscall(__NR_getrandom, buf, nbytes, 0));
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}
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#elif __has_include(<sys/random.h>) && (defined(__CYGWIN__) || defined(__Fuchsia__) || defined(__wasi__))
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__swift_size_t getentropy_nbytes = std::min(nbytes, __swift_size_t{256});
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if (0 == getentropy(buf, getentropy_nbytes)) {
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actual_nbytes = getentropy_nbytes;
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}
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#endif
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if (actual_nbytes == -1) {
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static const int fd =
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WHILE_EINTR(open("/dev/urandom", O_RDONLY | O_CLOEXEC, 0));
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if (fd != -1) {
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// ###FIXME: Why is this locked? None of the others are.
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static LazyMutex mutex;
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mutex.withLock([&] {
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actual_nbytes = WHILE_EINTR(read(fd, buf, nbytes));
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});
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}
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}
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if (actual_nbytes == -1) {
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fatalError(0, "Fatal error: %d in '%s'\n", errno, __func__);
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}
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buf = static_cast<uint8_t *>(buf) + actual_nbytes;
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nbytes -= actual_nbytes;
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}
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}
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#endif
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