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      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 #define LOG_TAG "ANDROID_RUNTIME_LAZY"
     17 #include "android_runtime/AndroidRuntime.h"
     18 #include "android_util_Binder.h"
     19 
     20 #include <dlfcn.h>
     21 #include <mutex>
     22 
     23 #include <log/log.h>
     24 
     25 namespace android {
     26 namespace {
     27 
     28 std::once_flag loadFlag;
     29 
     30 typedef JNIEnv* (*getJNIEnv_t)();
     31 typedef sp<IBinder> (*ibinderForJavaObject_t)(JNIEnv* env, jobject obj);
     32 typedef jobject (*javaObjectForIBinder_t)(JNIEnv* env, const sp<IBinder>& val);
     33 
     34 getJNIEnv_t _getJNIEnv;
     35 ibinderForJavaObject_t _ibinderForJavaObject;
     36 javaObjectForIBinder_t _javaObjectForIBinder;
     37 
     38 void load() {
     39     std::call_once(loadFlag, []() {
     40         void* handle = dlopen("libandroid_runtime.so", RTLD_LAZY);
     41         if (handle == nullptr) {
     42             ALOGE("Could not open libandroid_runtime.");
     43             return;
     44         }
     45 
     46         _getJNIEnv = reinterpret_cast<getJNIEnv_t>(
     47                 dlsym(handle, "_ZN7android14AndroidRuntime9getJNIEnvEv"));
     48         if (_getJNIEnv == nullptr) {
     49             ALOGW("Could not find getJNIEnv.");
     50             // no return
     51         }
     52 
     53         _ibinderForJavaObject = reinterpret_cast<ibinderForJavaObject_t>(
     54                 dlsym(handle, "_ZN7android20ibinderForJavaObjectEP7_JNIEnvP8_jobject"));
     55         if (_ibinderForJavaObject == nullptr) {
     56             ALOGW("Could not find ibinderForJavaObject.");
     57             // no return
     58         }
     59 
     60         _javaObjectForIBinder = reinterpret_cast<javaObjectForIBinder_t>(
     61                 dlsym(handle,
     62                       "_ZN7android20javaObjectForIBinderEP7_JNIEnvRKNS_2spINS_7IBinderEEE"));
     63         if (_javaObjectForIBinder == nullptr) {
     64             ALOGW("Could not find javaObjectForIBinder.");
     65             // no return
     66         }
     67     });
     68 }
     69 
     70 } // namespace
     71 
     72 // exports delegate functions
     73 
     74 JNIEnv* AndroidRuntime::getJNIEnv() {
     75     load();
     76     if (_getJNIEnv == nullptr) {
     77         return nullptr;
     78     }
     79     return _getJNIEnv();
     80 }
     81 
     82 sp<IBinder> ibinderForJavaObject(JNIEnv* env, jobject obj) {
     83     load();
     84     if (_ibinderForJavaObject == nullptr) {
     85         return nullptr;
     86     }
     87     return _ibinderForJavaObject(env, obj);
     88 }
     89 
     90 jobject javaObjectForIBinder(JNIEnv* env, const sp<IBinder>& val) {
     91     load();
     92     if (_javaObjectForIBinder == nullptr) {
     93         return nullptr;
     94     }
     95     return _javaObjectForIBinder(env, val);
     96 }
     97 
     98 } // namespace android
     99