Mark Salyzyn | 6c6ec72 | 2015-10-24 16:20:18 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2018 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | #include "epoll.h" |
| 18 | |
Mark Salyzyn | 37bbf80 | 2019-03-13 07:25:52 -0700 | [diff] [blame] | 19 | #include <stdint.h> |
Mark Salyzyn | 6c6ec72 | 2015-10-24 16:20:18 -0700 | [diff] [blame] | 20 | #include <sys/epoll.h> |
| 21 | |
| 22 | #include <chrono> |
| 23 | #include <functional> |
| 24 | #include <map> |
| 25 | |
David Anderson | 0fa7c40 | 2022-03-07 19:10:57 -0800 | [diff] [blame] | 26 | #include <android-base/logging.h> |
| 27 | |
Mark Salyzyn | 6c6ec72 | 2015-10-24 16:20:18 -0700 | [diff] [blame] | 28 | namespace android { |
| 29 | namespace init { |
| 30 | |
| 31 | Epoll::Epoll() {} |
| 32 | |
Tom Cherry | bbcbc2f | 2019-06-10 11:08:01 -0700 | [diff] [blame] | 33 | Result<void> Epoll::Open() { |
| 34 | if (epoll_fd_ >= 0) return {}; |
Mark Salyzyn | 6c6ec72 | 2015-10-24 16:20:18 -0700 | [diff] [blame] | 35 | epoll_fd_.reset(epoll_create1(EPOLL_CLOEXEC)); |
| 36 | |
| 37 | if (epoll_fd_ == -1) { |
| 38 | return ErrnoError() << "epoll_create1 failed"; |
| 39 | } |
Tom Cherry | bbcbc2f | 2019-06-10 11:08:01 -0700 | [diff] [blame] | 40 | return {}; |
Mark Salyzyn | 6c6ec72 | 2015-10-24 16:20:18 -0700 | [diff] [blame] | 41 | } |
| 42 | |
David Anderson | 1de7384 | 2021-05-13 20:18:14 -0700 | [diff] [blame] | 43 | Result<void> Epoll::RegisterHandler(int fd, Handler handler, uint32_t events) { |
Mark Salyzyn | 37bbf80 | 2019-03-13 07:25:52 -0700 | [diff] [blame] | 44 | if (!events) { |
| 45 | return Error() << "Must specify events"; |
| 46 | } |
David Anderson | 0fa7c40 | 2022-03-07 19:10:57 -0800 | [diff] [blame] | 47 | |
| 48 | Info info; |
| 49 | info.events = events; |
| 50 | info.handler = std::make_shared<decltype(handler)>(std::move(handler)); |
| 51 | auto [it, inserted] = epoll_handlers_.emplace(fd, std::move(info)); |
Mark Salyzyn | 6c6ec72 | 2015-10-24 16:20:18 -0700 | [diff] [blame] | 52 | if (!inserted) { |
| 53 | return Error() << "Cannot specify two epoll handlers for a given FD"; |
| 54 | } |
| 55 | epoll_event ev; |
Mark Salyzyn | 37bbf80 | 2019-03-13 07:25:52 -0700 | [diff] [blame] | 56 | ev.events = events; |
Mark Salyzyn | 6c6ec72 | 2015-10-24 16:20:18 -0700 | [diff] [blame] | 57 | // std::map's iterators do not get invalidated until erased, so we use the |
| 58 | // pointer to the std::function in the map directly for epoll_ctl. |
| 59 | ev.data.ptr = reinterpret_cast<void*>(&it->second); |
| 60 | if (epoll_ctl(epoll_fd_, EPOLL_CTL_ADD, fd, &ev) == -1) { |
Tom Cherry | bbcbc2f | 2019-06-10 11:08:01 -0700 | [diff] [blame] | 61 | Result<void> result = ErrnoError() << "epoll_ctl failed to add fd"; |
Mark Salyzyn | 6c6ec72 | 2015-10-24 16:20:18 -0700 | [diff] [blame] | 62 | epoll_handlers_.erase(fd); |
| 63 | return result; |
| 64 | } |
Tom Cherry | bbcbc2f | 2019-06-10 11:08:01 -0700 | [diff] [blame] | 65 | return {}; |
Mark Salyzyn | 6c6ec72 | 2015-10-24 16:20:18 -0700 | [diff] [blame] | 66 | } |
| 67 | |
Tom Cherry | bbcbc2f | 2019-06-10 11:08:01 -0700 | [diff] [blame] | 68 | Result<void> Epoll::UnregisterHandler(int fd) { |
Mark Salyzyn | 6c6ec72 | 2015-10-24 16:20:18 -0700 | [diff] [blame] | 69 | if (epoll_ctl(epoll_fd_, EPOLL_CTL_DEL, fd, nullptr) == -1) { |
| 70 | return ErrnoError() << "epoll_ctl failed to remove fd"; |
| 71 | } |
| 72 | if (epoll_handlers_.erase(fd) != 1) { |
| 73 | return Error() << "Attempting to remove epoll handler for FD without an existing handler"; |
| 74 | } |
Tom Cherry | bbcbc2f | 2019-06-10 11:08:01 -0700 | [diff] [blame] | 75 | return {}; |
Mark Salyzyn | 6c6ec72 | 2015-10-24 16:20:18 -0700 | [diff] [blame] | 76 | } |
| 77 | |
David Anderson | 1de7384 | 2021-05-13 20:18:14 -0700 | [diff] [blame] | 78 | Result<std::vector<std::shared_ptr<Epoll::Handler>>> Epoll::Wait( |
Tom Cherry | 905a5df | 2019-08-30 14:12:56 -0700 | [diff] [blame] | 79 | std::optional<std::chrono::milliseconds> timeout) { |
Mark Salyzyn | 6c6ec72 | 2015-10-24 16:20:18 -0700 | [diff] [blame] | 80 | int timeout_ms = -1; |
| 81 | if (timeout && timeout->count() < INT_MAX) { |
| 82 | timeout_ms = timeout->count(); |
| 83 | } |
Tom Cherry | 905a5df | 2019-08-30 14:12:56 -0700 | [diff] [blame] | 84 | const auto max_events = epoll_handlers_.size(); |
| 85 | epoll_event ev[max_events]; |
| 86 | auto num_events = TEMP_FAILURE_RETRY(epoll_wait(epoll_fd_, ev, max_events, timeout_ms)); |
| 87 | if (num_events == -1) { |
Mark Salyzyn | 6c6ec72 | 2015-10-24 16:20:18 -0700 | [diff] [blame] | 88 | return ErrnoError() << "epoll_wait failed"; |
Mark Salyzyn | 6c6ec72 | 2015-10-24 16:20:18 -0700 | [diff] [blame] | 89 | } |
David Anderson | 1de7384 | 2021-05-13 20:18:14 -0700 | [diff] [blame] | 90 | std::vector<std::shared_ptr<Handler>> pending_functions; |
Tom Cherry | 905a5df | 2019-08-30 14:12:56 -0700 | [diff] [blame] | 91 | for (int i = 0; i < num_events; ++i) { |
David Anderson | 0fa7c40 | 2022-03-07 19:10:57 -0800 | [diff] [blame] | 92 | auto& info = *reinterpret_cast<Info*>(ev[i].data.ptr); |
| 93 | if ((info.events & (EPOLLIN | EPOLLPRI)) == (EPOLLIN | EPOLLPRI) && |
| 94 | (ev[i].events & EPOLLIN) != ev[i].events) { |
| 95 | // This handler wants to know about exception events, and just got one. |
| 96 | // Log something informational. |
| 97 | LOG(ERROR) << "Received unexpected epoll event set: " << ev[i].events; |
| 98 | } |
| 99 | pending_functions.emplace_back(info.handler); |
Tom Cherry | 905a5df | 2019-08-30 14:12:56 -0700 | [diff] [blame] | 100 | } |
| 101 | |
| 102 | return pending_functions; |
Mark Salyzyn | 6c6ec72 | 2015-10-24 16:20:18 -0700 | [diff] [blame] | 103 | } |
| 104 | |
| 105 | } // namespace init |
| 106 | } // namespace android |