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 #include "plugin.h"
18 
19 #include <dlfcn.h>
20 
21 #include "android-base/stringprintf.h"
22 
23 #include "base/logging.h"
24 
25 namespace art {
26 
27 using android::base::StringPrintf;
28 
29 const char* PLUGIN_INITIALIZATION_FUNCTION_NAME = "ArtPlugin_Initialize";
30 const char* PLUGIN_DEINITIALIZATION_FUNCTION_NAME = "ArtPlugin_Deinitialize";
31 
Plugin(const Plugin & other)32 Plugin::Plugin(const Plugin& other) : library_(other.library_), dlopen_handle_(nullptr) {
33   if (other.IsLoaded()) {
34     std::string err;
35     Load(&err);
36   }
37 }
38 
Load(std::string * error_msg)39 bool Plugin::Load(/*out*/std::string* error_msg) {
40   DCHECK(!IsLoaded());
41   void* res = dlopen(library_.c_str(), RTLD_LAZY);
42   if (res == nullptr) {
43     *error_msg = StringPrintf("dlopen failed: %s", dlerror());
44     return false;
45   }
46   // Get the initializer function
47   PluginInitializationFunction init = reinterpret_cast<PluginInitializationFunction>(
48       dlsym(res, PLUGIN_INITIALIZATION_FUNCTION_NAME));
49   if (init != nullptr) {
50     if (!init()) {
51       dlclose(res);
52       *error_msg = StringPrintf("Initialization of plugin failed");
53       return false;
54     }
55   } else {
56     LOG(WARNING) << this << " does not include an initialization function";
57   }
58   dlopen_handle_ = res;
59   return true;
60 }
61 
Unload()62 bool Plugin::Unload() {
63   DCHECK(IsLoaded());
64   bool ret = true;
65   void* handle = dlopen_handle_;
66   PluginDeinitializationFunction deinit = reinterpret_cast<PluginDeinitializationFunction>(
67       dlsym(handle, PLUGIN_DEINITIALIZATION_FUNCTION_NAME));
68   if (deinit != nullptr) {
69     if (!deinit()) {
70       LOG(WARNING) << this << " failed deinitialization";
71       ret = false;
72     }
73   } else {
74     LOG(WARNING) << this << " does not include a deinitialization function";
75   }
76   dlopen_handle_ = nullptr;
77   if (dlclose(handle) != 0) {
78     LOG(ERROR) << this << " failed to dlclose: " << dlerror();
79     ret = false;
80   }
81   return ret;
82 }
83 
operator <<(std::ostream & os,const Plugin * m)84 std::ostream& operator<<(std::ostream &os, const Plugin* m) {
85   return os << *m;
86 }
87 
operator <<(std::ostream & os,Plugin const & m)88 std::ostream& operator<<(std::ostream &os, Plugin const& m) {
89   return os << "Plugin { library=\"" << m.library_ << "\", handle=" << m.dlopen_handle_ << " }";
90 }
91 
92 }  // namespace art
93