1 /*
2  * Copyright (C) 2016 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 ART_RUNTIME_PLUGIN_H_
18 #define ART_RUNTIME_PLUGIN_H_
19 
20 #include <string>
21 
22 #include <android-base/logging.h>
23 
24 #include "base/macros.h"
25 
26 namespace art HIDDEN {
27 
28 // This function is loaded from the plugin (if present) and called during runtime initialization.
29 // By the time this has been called the runtime has been fully initialized but not other native
30 // libraries have been loaded yet. Failure to initialize is considered a fatal error.
31 // TODO might want to give initialization function some arguments
32 using PluginInitializationFunction = bool (*)();
33 using PluginDeinitializationFunction = bool (*)();
34 
35 // A class encapsulating a plugin. There is no stable plugin ABI or API and likely never will be.
36 // TODO Might want to put some locking in this but ATM we only load these at initialization in a
37 // single-threaded fashion so not much need
38 class Plugin {
39  public:
Create(const std::string & lib)40   static Plugin Create(const std::string& lib) {
41     return Plugin(lib);
42   }
43 
IsLoaded()44   bool IsLoaded() const {
45     return dlopen_handle_ != nullptr;
46   }
47 
GetLibrary()48   const std::string& GetLibrary() const {
49     return library_;
50   }
51 
52   bool Load(/*out*/std::string* error_msg);
53   bool Unload();
54 
55 
~Plugin()56   ~Plugin() {
57     if (IsLoaded() && !Unload()) {
58       LOG(ERROR) << "Error unloading " << this;
59     }
60   }
61 
62   Plugin(const Plugin& other);
63 
64   // Create move constructor for putting this in a list
Plugin(Plugin && other)65   Plugin(Plugin&& other) noexcept
66       : library_(other.library_),
67         dlopen_handle_(other.dlopen_handle_) {
68     other.dlopen_handle_ = nullptr;
69   }
70 
71  private:
Plugin(const std::string & library)72   explicit Plugin(const std::string& library) : library_(library), dlopen_handle_(nullptr) { }
73 
74   std::string library_;
75   void* dlopen_handle_;
76 
77   friend std::ostream& operator<<(std::ostream &os, Plugin const& m);
78 };
79 
80 std::ostream& operator<<(std::ostream &os, Plugin const& m);
81 std::ostream& operator<<(std::ostream &os, const Plugin* m);
82 
83 }  // namespace art
84 
85 #endif  // ART_RUNTIME_PLUGIN_H_
86