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/*
* Copyright (C) 2019 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 "fdevent_epoll.h"
#if defined(__linux__)
#include <sys/epoll.h>
#include <sys/eventfd.h>
#include <android-base/logging.h>
#include <android-base/threads.h>
#include "adb_unique_fd.h"
#include "fdevent.h"
static void fdevent_interrupt(int fd, unsigned, void*) {
uint64_t buf;
ssize_t rc = TEMP_FAILURE_RETRY(adb_read(fd, &buf, sizeof(buf)));
if (rc == -1) {
PLOG(FATAL) << "failed to read from fdevent interrupt fd";
}
}
fdevent_context_epoll::fdevent_context_epoll() {
epoll_fd_.reset(epoll_create1(EPOLL_CLOEXEC));
unique_fd interrupt_fd(eventfd(0, EFD_CLOEXEC | EFD_NONBLOCK));
if (interrupt_fd == -1) {
PLOG(FATAL) << "failed to create fdevent interrupt eventfd";
}
unique_fd interrupt_fd_dup(fcntl(interrupt_fd.get(), F_DUPFD_CLOEXEC, 3));
if (interrupt_fd_dup == -1) {
PLOG(FATAL) << "failed to dup fdevent interrupt eventfd";
}
this->interrupt_fd_ = std::move(interrupt_fd_dup);
fdevent* fde = this->Create(std::move(interrupt_fd), fdevent_interrupt, nullptr);
CHECK(fde != nullptr);
this->Add(fde, FDE_READ);
}
fdevent_context_epoll::~fdevent_context_epoll() {
// Destroy calls virtual methods, but this class is final, so that's okay.
this->Destroy(this->interrupt_fde_);
}
static epoll_event calculate_epoll_event(fdevent* fde) {
epoll_event result;
result.events = 0;
if (fde->state & FDE_READ) {
result.events |= EPOLLIN;
}
if (fde->state & FDE_WRITE) {
result.events |= EPOLLOUT;
}
if (fde->state & FDE_ERROR) {
result.events |= EPOLLERR;
}
result.events |= EPOLLRDHUP;
result.data.ptr = fde;
return result;
}
void fdevent_context_epoll::Register(fdevent* fde) {
epoll_event ev = calculate_epoll_event(fde);
if (epoll_ctl(epoll_fd_.get(), EPOLL_CTL_ADD, fde->fd.get(), &ev) != 0) {
PLOG(FATAL) << "failed to register fd " << fde->fd.get() << " with epoll";
}
}
void fdevent_context_epoll::Unregister(fdevent* fde) {
if (epoll_ctl(epoll_fd_.get(), EPOLL_CTL_DEL, fde->fd.get(), nullptr) != 0) {
PLOG(FATAL) << "failed to unregister fd " << fde->fd.get() << " with epoll";
}
}
void fdevent_context_epoll::Set(fdevent* fde, unsigned events) {
unsigned previous_state = fde->state;
fde->state = events;
// If the state is the same, or only differed by FDE_TIMEOUT, we don't need to modify epoll.
if ((previous_state & ~FDE_TIMEOUT) == (events & ~FDE_TIMEOUT)) {
return;
}
epoll_event ev = calculate_epoll_event(fde);
if (epoll_ctl(epoll_fd_.get(), EPOLL_CTL_MOD, fde->fd.get(), &ev) != 0) {
PLOG(FATAL) << "failed to modify fd " << fde->fd.get() << " with epoll";
}
}
void fdevent_context_epoll::Loop() {
looper_thread_id_ = android::base::GetThreadId();
std::vector<fdevent_event> fde_events;
std::vector<epoll_event> epoll_events;
epoll_events.resize(this->installed_fdevents_.size());
while (true) {
if (terminate_loop_) {
break;
}
int rc = -1;
while (rc == -1) {
std::optional<std::chrono::milliseconds> timeout = CalculatePollDuration();
int timeout_ms;
if (!timeout) {
timeout_ms = -1;
} else {
timeout_ms = timeout->count();
}
rc = epoll_wait(epoll_fd_.get(), epoll_events.data(), epoll_events.size(), timeout_ms);
if (rc == -1 && errno != EINTR) {
PLOG(FATAL) << "epoll_wait failed";
}
}
auto post_poll = std::chrono::steady_clock::now();
std::unordered_map<fdevent*, unsigned> event_map;
for (int i = 0; i < rc; ++i) {
fdevent* fde = static_cast<fdevent*>(epoll_events[i].data.ptr);
unsigned events = 0;
if (epoll_events[i].events & EPOLLIN) {
CHECK(fde->state & FDE_READ);
events |= FDE_READ;
}
if (epoll_events[i].events & EPOLLOUT) {
CHECK(fde->state & FDE_WRITE);
events |= FDE_WRITE;
}
if (epoll_events[i].events & (EPOLLERR | EPOLLHUP | EPOLLRDHUP)) {
// We fake a read, as the rest of the code assumes that errors will
// be detected at that point.
events |= FDE_READ | FDE_ERROR;
}
event_map[fde] = events;
}
for (auto& [fd, fde] : installed_fdevents_) {
unsigned events = 0;
if (auto it = event_map.find(&fde); it != event_map.end()) {
events = it->second;
}
if (events == 0) {
if (fde.timeout) {
auto deadline = fde.last_active + *fde.timeout;
if (deadline < post_poll) {
events |= FDE_TIMEOUT;
}
}
}
if (events != 0) {
LOG(DEBUG) << dump_fde(&fde) << " got events " << std::hex << std::showbase
<< events;
fde_events.push_back({&fde, events});
fde.last_active = post_poll;
}
}
this->HandleEvents(fde_events);
fde_events.clear();
}
looper_thread_id_.reset();
}
size_t fdevent_context_epoll::InstalledCount() {
// We always have an installed fde for interrupt.
return this->installed_fdevents_.size() - 1;
}
void fdevent_context_epoll::Interrupt() {
uint64_t i = 1;
ssize_t rc = TEMP_FAILURE_RETRY(adb_write(this->interrupt_fd_, &i, sizeof(i)));
if (rc != sizeof(i)) {
PLOG(FATAL) << "failed to write to fdevent interrupt eventfd";
}
}
#endif // defined(__linux__)
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