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/*
* Copyright (C) 2016 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 "IOEventLoop.h"
#include <event2/event.h>
#include <fcntl.h>
#include <android-base/logging.h>
namespace simpleperf {
struct IOEvent {
IOEventLoop* loop;
event* e;
timeval timeout;
std::function<bool()> callback;
bool enabled;
IOEvent(IOEventLoop* loop, const std::function<bool()>& callback)
: loop(loop), e(nullptr), timeout({}), callback(callback), enabled(false) {}
~IOEvent() {
if (e != nullptr) {
event_free(e);
}
}
};
IOEventLoop::IOEventLoop() : ebase_(nullptr), has_error_(false), in_loop_(false) {}
IOEventLoop::~IOEventLoop() {
events_.clear();
if (ebase_ != nullptr) {
event_base_free(ebase_);
}
}
bool IOEventLoop::EnsureInit() {
if (ebase_ == nullptr) {
event_config* cfg = event_config_new();
if (cfg != nullptr) {
event_config_set_flag(cfg, EVENT_BASE_FLAG_PRECISE_TIMER);
if (event_config_avoid_method(cfg, "epoll") != 0) {
LOG(ERROR) << "event_config_avoid_method";
return false;
}
ebase_ = event_base_new_with_config(cfg);
// perf event files support reporting available data via poll methods. However, it doesn't
// work well with epoll. Because perf_poll() in kernel/events/core.c uses a report and reset
// way to report poll events. If perf_poll() is called twice, it may return POLLIN for the
// first time, and no events for the second time. And epoll may call perf_poll() more than
// once to confirm events. A failed situation is below:
// When profiling SimpleperfExampleOfKotlin on Pixel device with `-g --duration 10`, the
// kernel fills up the buffer before we call epoll_ctl(EPOLL_CTL_ADD). Then the POLLIN event
// is returned when calling epoll_ctl(), while no events are returned when calling
// epoll_wait(). As a result, simpleperf doesn't receive any poll wakeup events.
if (strcmp(event_base_get_method(ebase_), "poll") != 0) {
LOG(ERROR) << "event_base_get_method isn't poll: " << event_base_get_method(ebase_);
return false;
}
event_config_free(cfg);
if (event_base_priority_init(ebase_, 2) != 0) {
LOG(ERROR) << "event_base_priority_init failed";
return false;
}
}
if (ebase_ == nullptr) {
LOG(ERROR) << "failed to create event_base";
return false;
}
}
return true;
}
void IOEventLoop::EventCallbackFn(int, int16_t, void* arg) {
IOEvent* e = static_cast<IOEvent*>(arg);
if (!e->callback()) {
e->loop->has_error_ = true;
e->loop->ExitLoop();
}
}
static bool MakeFdNonBlocking(int fd) {
int flags = fcntl(fd, F_GETFL, 0);
if (flags == -1 || fcntl(fd, F_SETFL, flags | O_NONBLOCK) == -1) {
PLOG(ERROR) << "fcntl() failed";
return false;
}
return true;
}
IOEventRef IOEventLoop::AddReadEvent(int fd, const std::function<bool()>& callback,
IOEventPriority priority) {
if (!MakeFdNonBlocking(fd)) {
return nullptr;
}
return AddEvent(fd, EV_READ | EV_PERSIST, nullptr, callback, priority);
}
IOEventRef IOEventLoop::AddWriteEvent(int fd, const std::function<bool()>& callback,
IOEventPriority priority) {
if (!MakeFdNonBlocking(fd)) {
return nullptr;
}
return AddEvent(fd, EV_WRITE | EV_PERSIST, nullptr, callback, priority);
}
bool IOEventLoop::AddSignalEvent(int sig, const std::function<bool()>& callback,
IOEventPriority priority) {
return AddEvent(sig, EV_SIGNAL | EV_PERSIST, nullptr, callback, priority) != nullptr;
}
bool IOEventLoop::AddSignalEvents(std::vector<int> sigs, const std::function<bool()>& callback,
IOEventPriority priority) {
for (auto sig : sigs) {
if (!AddSignalEvent(sig, callback, priority)) {
return false;
}
}
return true;
}
IOEventRef IOEventLoop::AddPeriodicEvent(timeval duration, const std::function<bool()>& callback,
IOEventPriority priority) {
return AddEvent(-1, EV_PERSIST, &duration, callback, priority);
}
IOEventRef IOEventLoop::AddOneTimeEvent(timeval duration, const std::function<bool()>& callback,
IOEventPriority priority) {
return AddEvent(-1, 0, &duration, callback, priority);
}
IOEventRef IOEventLoop::AddEvent(int fd_or_sig, int16_t events, timeval* timeout,
const std::function<bool()>& callback, IOEventPriority priority) {
if (!EnsureInit()) {
return nullptr;
}
std::unique_ptr<IOEvent> e(new IOEvent(this, callback));
e->e = event_new(ebase_, fd_or_sig, events, EventCallbackFn, e.get());
if (e->e == nullptr) {
LOG(ERROR) << "event_new() failed";
return nullptr;
}
event_priority_set(e->e, priority);
if (event_add(e->e, timeout) != 0) {
LOG(ERROR) << "event_add() failed";
return nullptr;
}
if (timeout != nullptr) {
e->timeout = *timeout;
}
e->enabled = true;
events_.push_back(std::move(e));
return events_.back().get();
}
bool IOEventLoop::RunLoop() {
in_loop_ = true;
if (event_base_dispatch(ebase_) == -1) {
LOG(ERROR) << "event_base_dispatch() failed";
in_loop_ = false;
return false;
}
if (has_error_) {
return false;
}
return true;
}
bool IOEventLoop::ExitLoop() {
if (in_loop_) {
if (event_base_loopbreak(ebase_) == -1) {
LOG(ERROR) << "event_base_loopbreak() failed";
return false;
}
in_loop_ = false;
}
return true;
}
bool IOEventLoop::DisableEvent(IOEventRef ref) {
if (ref->enabled) {
if (event_del(ref->e) != 0) {
LOG(ERROR) << "event_del() failed";
return false;
}
ref->enabled = false;
}
return true;
}
bool IOEventLoop::EnableEvent(IOEventRef ref) {
if (!ref->enabled) {
timeval* timeout =
(ref->timeout.tv_sec != 0 || ref->timeout.tv_usec != 0) ? &ref->timeout : nullptr;
if (event_add(ref->e, timeout) != 0) {
LOG(ERROR) << "event_add() failed";
return false;
}
ref->enabled = true;
}
return true;
}
bool IOEventLoop::DelEvent(IOEventRef ref) {
DisableEvent(ref);
IOEventLoop* loop = ref->loop;
for (auto it = loop->events_.begin(); it != loop->events_.end(); ++it) {
if (it->get() == ref) {
loop->events_.erase(it);
break;
}
}
return true;
}
} // namespace simpleperf
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