chromium/third_party/abseil-cpp/absl/synchronization/internal/waiter_test.cc

// Copyright 2023 The Abseil Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include "absl/synchronization/internal/waiter.h"

#include <ctime>
#include <iostream>
#include <ostream>

#include "absl/base/config.h"
#include "absl/random/random.h"
#include "absl/synchronization/internal/create_thread_identity.h"
#include "absl/synchronization/internal/futex_waiter.h"
#include "absl/synchronization/internal/kernel_timeout.h"
#include "absl/synchronization/internal/pthread_waiter.h"
#include "absl/synchronization/internal/sem_waiter.h"
#include "absl/synchronization/internal/stdcpp_waiter.h"
#include "absl/synchronization/internal/thread_pool.h"
#include "absl/synchronization/internal/win32_waiter.h"
#include "absl/time/clock.h"
#include "absl/time/time.h"
#include "gtest/gtest.h"

// Test go/btm support by randomizing the value of clock_gettime() for
// CLOCK_MONOTONIC. This works by overriding a weak symbol in glibc.
// We should be resistant to this randomization when !SupportsSteadyClock().
#if defined(__GOOGLE_GRTE_VERSION__) &&      \
    !defined(ABSL_HAVE_ADDRESS_SANITIZER) && \
    !defined(ABSL_HAVE_MEMORY_SANITIZER) &&  \
    !defined(ABSL_HAVE_THREAD_SANITIZER)
extern "C" int __clock_gettime(clockid_t c, struct timespec* ts);

extern "C" int clock_gettime(clockid_t c, struct timespec* ts) {
  if (c == CLOCK_MONOTONIC &&
      !absl::synchronization_internal::KernelTimeout::SupportsSteadyClock()) {
    thread_local absl::BitGen gen;  // NOLINT
    ts->tv_sec = absl::Uniform(gen, 0, 1'000'000'000);
    ts->tv_nsec = absl::Uniform(gen, 0, 1'000'000'000);
    return 0;
  }
  return __clock_gettime(c, ts);
}
#endif

namespace …  // namespace