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/*
* Copyright (C) 2018 The Android Open Source Project
*
* 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
*
* http://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 "perfetto/base/build_config.h"
#include <errno.h>
#include <stdint.h>
#if PERFETTO_BUILDFLAG(PERFETTO_OS_WIN)
#include <Windows.h>
#include <synchapi.h>
#elif PERFETTO_BUILDFLAG(PERFETTO_OS_LINUX) || \
PERFETTO_BUILDFLAG(PERFETTO_OS_ANDROID)
#include <sys/eventfd.h>
#include <unistd.h>
#else // Mac, Fuchsia and other non-Linux UNIXes
#include <unistd.h>
#endif
#include "perfetto/base/logging.h"
#include "perfetto/ext/base/event_fd.h"
#include "perfetto/ext/base/pipe.h"
#include "perfetto/ext/base/utils.h"
namespace perfetto {
namespace base {
EventFd::~EventFd() = default;
#if PERFETTO_BUILDFLAG(PERFETTO_OS_WIN)
EventFd::EventFd() {
event_handle_.reset(
CreateEventA(/*lpEventAttributes=*/nullptr, /*bManualReset=*/true,
/*bInitialState=*/false, /*bInitialState=*/nullptr));
}
void EventFd::Notify() {
if (!SetEvent(event_handle_.get())) // 0: fail, !0: success, unlike UNIX.
PERFETTO_DFATAL("EventFd::Notify()");
}
void EventFd::Clear() {
if (!ResetEvent(event_handle_.get())) // 0: fail, !0: success, unlike UNIX.
PERFETTO_DFATAL("EventFd::Clear()");
}
#elif PERFETTO_BUILDFLAG(PERFETTO_OS_LINUX) || \
PERFETTO_BUILDFLAG(PERFETTO_OS_ANDROID)
EventFd::EventFd() {
event_handle_.reset(eventfd(/*initval=*/0, EFD_CLOEXEC | EFD_NONBLOCK));
PERFETTO_CHECK(event_handle_);
}
void EventFd::Notify() {
const uint64_t value = 1;
ssize_t ret = write(event_handle_.get(), &value, sizeof(value));
if (ret <= 0 && errno != EAGAIN)
PERFETTO_DFATAL("EventFd::Notify()");
}
void EventFd::Clear() {
uint64_t value;
ssize_t ret =
PERFETTO_EINTR(read(event_handle_.get(), &value, sizeof(value)));
if (ret <= 0 && errno != EAGAIN)
PERFETTO_DFATAL("EventFd::Clear()");
}
#else
EventFd::EventFd() {
// Make the pipe non-blocking so that we never block the waking thread (either
// the main thread or another one) when scheduling a wake-up.
Pipe pipe = Pipe::Create(Pipe::kBothNonBlock);
event_handle_ = ScopedPlatformHandle(std::move(pipe.rd).release());
write_fd_ = std::move(pipe.wr);
}
void EventFd::Notify() {
const uint64_t value = 1;
ssize_t ret = write(write_fd_.get(), &value, sizeof(uint8_t));
if (ret <= 0 && errno != EAGAIN)
PERFETTO_DFATAL("EventFd::Notify()");
}
void EventFd::Clear() {
// Drain the byte(s) written to the wake-up pipe. We can potentially read
// more than one byte if several wake-ups have been scheduled.
char buffer[16];
ssize_t ret =
PERFETTO_EINTR(read(event_handle_.get(), &buffer[0], sizeof(buffer)));
if (ret <= 0 && errno != EAGAIN)
PERFETTO_DFATAL("EventFd::Clear()");
}
#endif
} // namespace base
} // namespace perfetto
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