1 /* 2 * Copyright (C) 2017 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 #ifndef _INIT_UEVENT_LISTENER_H 18 #define _INIT_UEVENT_LISTENER_H 19 20 #include <dirent.h> 21 22 #include <chrono> 23 #include <functional> 24 #include <optional> 25 26 #include <android-base/unique_fd.h> 27 28 #include "uevent.h" 29 30 #define UEVENT_MSG_LEN 8192 31 32 namespace android { 33 namespace init { 34 35 enum class ListenerAction { 36 kStop = 0, // Stop regenerating uevents as we've handled the one(s) we're interested in. 37 kContinue, // Continue regenerating uevents as we haven't seen the one(s) we're interested in. 38 }; 39 40 enum class ReadUeventResult { 41 kSuccess = 0, // Uevent was successfully read. 42 kFailed, // Uevent reading has failed. 43 kInvalid, // An Invalid Uevent was read (like say, the msg received is >= UEVENT_MSG_LEN). 44 }; 45 46 using ListenerCallback = std::function<ListenerAction(const Uevent&)>; 47 48 class UeventListener { 49 public: 50 UeventListener(size_t uevent_socket_rcvbuf_size); 51 52 void RegenerateUevents(const ListenerCallback& callback) const; 53 ListenerAction RegenerateUeventsForPath(const std::string& path, 54 const ListenerCallback& callback) const; 55 void Poll(const ListenerCallback& callback, 56 const std::optional<std::chrono::milliseconds> relative_timeout = {}) const; 57 58 private: 59 ReadUeventResult ReadUevent(Uevent* uevent) const; 60 ListenerAction RegenerateUeventsForDir(DIR* d, const ListenerCallback& callback) const; 61 62 android::base::unique_fd device_fd_; 63 }; 64 65 } // namespace init 66 } // namespace android 67 68 #endif 69