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 2048
31
32namespace android {
33namespace init {
34
35enum 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
40using ListenerCallback = std::function<ListenerAction(const Uevent&)>;
41
42class UeventListener {
43  public:
44    UeventListener();
45
46    void RegenerateUevents(const ListenerCallback& callback) const;
47    ListenerAction RegenerateUeventsForPath(const std::string& path,
48                                            const ListenerCallback& callback) const;
49    void Poll(const ListenerCallback& callback,
50              const std::optional<std::chrono::milliseconds> relative_timeout = {}) const;
51
52  private:
53    bool ReadUevent(Uevent* uevent) const;
54    ListenerAction RegenerateUeventsForDir(DIR* d, const ListenerCallback& callback) const;
55
56    android::base::unique_fd device_fd_;
57};
58
59}  // namespace init
60}  // namespace android
61
62#endif
63