1 /*
2  * Copyright (C) 2019 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 #pragma once
18 
19 #include <sys/cdefs.h>
20 #include <sys/types.h>
21 
22 #include <map>
23 #include <memory>
24 #include <mutex>
25 #include <string>
26 #include <vector>
27 
28 #include <android/cgrouprc.h>
29 
30 // Convenient wrapper of an ACgroupController pointer.
31 class CgroupController {
32   public:
33     // Does not own controller
CgroupController(const ACgroupController * controller)34     explicit CgroupController(const ACgroupController* controller)
35         : controller_(controller), state_(UNKNOWN) {}
36 
37     uint32_t version() const;
38     const char* name() const;
39     const char* path() const;
40 
41     bool HasValue() const;
42     bool IsUsable();
43 
44     std::string GetTasksFilePath(const std::string& path) const;
45     std::string GetProcsFilePath(const std::string& path, uid_t uid, pid_t pid) const;
46     bool GetTaskGroup(int tid, std::string* group) const;
47   private:
48     enum ControllerState {
49         UNKNOWN = 0,
50         USABLE = 1,
51         MISSING = 2,
52     };
53 
54     const ACgroupController* controller_ = nullptr;
55     ControllerState state_;
56 };
57 
58 class CgroupMap {
59   public:
60     // Selinux policy ensures only init process can successfully use this function
61     static bool SetupCgroups();
62 
63     static CgroupMap& GetInstance();
64     CgroupController FindController(const std::string& name) const;
65 
66   private:
67     bool loaded_ = false;
68     CgroupMap();
69     bool LoadRcFile();
70     void Print() const;
71 };
72