aea9781530
Ignore-AOSP-First: Awaiting security triage Bug: 187862380 Test: CtsInitTestCases Change-Id: Ibb34a6b8a5675dbc515b7f8a43d7eecf2084510c
95 lines
3 KiB
C++
95 lines
3 KiB
C++
/*
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* Copyright (C) 2018 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "epoll.h"
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#include <stdint.h>
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#include <sys/epoll.h>
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#include <chrono>
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#include <functional>
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#include <map>
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namespace android {
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namespace init {
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Epoll::Epoll() {}
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Result<void> Epoll::Open() {
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if (epoll_fd_ >= 0) return {};
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epoll_fd_.reset(epoll_create1(EPOLL_CLOEXEC));
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if (epoll_fd_ == -1) {
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return ErrnoError() << "epoll_create1 failed";
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}
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return {};
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}
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Result<void> Epoll::RegisterHandler(int fd, Handler handler, uint32_t events) {
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if (!events) {
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return Error() << "Must specify events";
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}
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auto sp = std::make_shared<decltype(handler)>(std::move(handler));
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auto [it, inserted] = epoll_handlers_.emplace(fd, std::move(sp));
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if (!inserted) {
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return Error() << "Cannot specify two epoll handlers for a given FD";
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}
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epoll_event ev;
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ev.events = events;
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// std::map's iterators do not get invalidated until erased, so we use the
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// pointer to the std::function in the map directly for epoll_ctl.
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ev.data.ptr = reinterpret_cast<void*>(&it->second);
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if (epoll_ctl(epoll_fd_, EPOLL_CTL_ADD, fd, &ev) == -1) {
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Result<void> result = ErrnoError() << "epoll_ctl failed to add fd";
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epoll_handlers_.erase(fd);
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return result;
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}
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return {};
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}
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Result<void> Epoll::UnregisterHandler(int fd) {
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if (epoll_ctl(epoll_fd_, EPOLL_CTL_DEL, fd, nullptr) == -1) {
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return ErrnoError() << "epoll_ctl failed to remove fd";
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}
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if (epoll_handlers_.erase(fd) != 1) {
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return Error() << "Attempting to remove epoll handler for FD without an existing handler";
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}
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return {};
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}
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Result<std::vector<std::shared_ptr<Epoll::Handler>>> Epoll::Wait(
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std::optional<std::chrono::milliseconds> timeout) {
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int timeout_ms = -1;
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if (timeout && timeout->count() < INT_MAX) {
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timeout_ms = timeout->count();
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}
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const auto max_events = epoll_handlers_.size();
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epoll_event ev[max_events];
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auto num_events = TEMP_FAILURE_RETRY(epoll_wait(epoll_fd_, ev, max_events, timeout_ms));
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if (num_events == -1) {
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return ErrnoError() << "epoll_wait failed";
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}
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std::vector<std::shared_ptr<Handler>> pending_functions;
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for (int i = 0; i < num_events; ++i) {
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auto sp = *reinterpret_cast<std::shared_ptr<Handler>*>(ev[i].data.ptr);
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pending_functions.emplace_back(std::move(sp));
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}
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return pending_functions;
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}
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} // namespace init
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} // namespace android
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