1 /*
2  * Copyright (C) 2014 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 "native_bridge_art_interface.h"
18 
19 #include "nativebridge/native_bridge.h"
20 
21 #include "base/logging.h"
22 #include "mirror/art_method-inl.h"
23 #include "mirror/class-inl.h"
24 #include "scoped_thread_state_change.h"
25 
26 namespace art {
27 
GetMethodShorty(JNIEnv * env,jmethodID mid)28 const char* GetMethodShorty(JNIEnv* env, jmethodID mid) {
29   ScopedObjectAccess soa(env);
30   StackHandleScope<1> scope(soa.Self());
31   mirror::ArtMethod* m = soa.DecodeMethod(mid);
32   MethodHelper mh(scope.NewHandle(m));
33   return mh.GetShorty();
34 }
35 
GetNativeMethodCount(JNIEnv * env,jclass clazz)36 uint32_t GetNativeMethodCount(JNIEnv* env, jclass clazz) {
37   if (clazz == nullptr)
38     return 0;
39 
40   ScopedObjectAccess soa(env);
41   mirror::Class* c = soa.Decode<mirror::Class*>(clazz);
42 
43   uint32_t native_method_count = 0;
44   for (uint32_t i = 0; i < c->NumDirectMethods(); ++i) {
45     mirror::ArtMethod* m = c->GetDirectMethod(i);
46     if (m->IsNative()) {
47       native_method_count++;
48     }
49   }
50   for (uint32_t i = 0; i < c->NumVirtualMethods(); ++i) {
51     mirror::ArtMethod* m = c->GetVirtualMethod(i);
52     if (m->IsNative()) {
53       native_method_count++;
54     }
55   }
56   return native_method_count;
57 }
58 
GetNativeMethods(JNIEnv * env,jclass clazz,JNINativeMethod * methods,uint32_t method_count)59 uint32_t GetNativeMethods(JNIEnv* env, jclass clazz, JNINativeMethod* methods,
60                           uint32_t method_count) {
61   if ((clazz == nullptr) || (methods == nullptr)) {
62     return 0;
63   }
64   ScopedObjectAccess soa(env);
65   mirror::Class* c = soa.Decode<mirror::Class*>(clazz);
66 
67   uint32_t count = 0;
68   for (uint32_t i = 0; i < c->NumDirectMethods(); ++i) {
69     mirror::ArtMethod* m = c->GetDirectMethod(i);
70     if (m->IsNative()) {
71       if (count < method_count) {
72         methods[count].name = m->GetName();
73         methods[count].signature = m->GetShorty();
74         methods[count].fnPtr = m->GetEntryPointFromJni();
75         count++;
76       } else {
77         LOG(WARNING) << "Output native method array too small. Skipping " << PrettyMethod(m);
78       }
79     }
80   }
81   for (uint32_t i = 0; i < c->NumVirtualMethods(); ++i) {
82     mirror::ArtMethod* m = c->GetVirtualMethod(i);
83     if (m->IsNative()) {
84       if (count < method_count) {
85         methods[count].name = m->GetName();
86         methods[count].signature = m->GetShorty();
87         methods[count].fnPtr = m->GetEntryPointFromJni();
88         count++;
89       } else {
90         LOG(WARNING) << "Output native method array too small. Skipping " << PrettyMethod(m);
91       }
92     }
93   }
94   return count;
95 }
96 
97 // Native bridge library runtime callbacks. They represent the runtime interface to native bridge.
98 //
99 // The interface is expected to expose the following methods:
100 // getMethodShorty(): in the case of native method calling JNI native function CallXXXXMethodY(),
101 //   native bridge calls back to VM for the shorty of the method so that it can prepare based on
102 //   host calling convention.
103 // getNativeMethodCount() and getNativeMethods(): in case of JNI function UnregisterNatives(),
104 //   native bridge can call back to get all native methods of specified class so that all
105 //   corresponding trampolines can be destroyed.
106 static android::NativeBridgeRuntimeCallbacks native_bridge_art_callbacks_ {
107   GetMethodShorty, GetNativeMethodCount, GetNativeMethods
108 };
109 
LoadNativeBridge(std::string & native_bridge_library_filename)110 bool LoadNativeBridge(std::string& native_bridge_library_filename) {
111   VLOG(startup) << "Runtime::Setup native bridge library: "
112       << (native_bridge_library_filename.empty() ? "(empty)" : native_bridge_library_filename);
113   return android::LoadNativeBridge(native_bridge_library_filename.c_str(),
114                                    &native_bridge_art_callbacks_);
115 }
116 
PreInitializeNativeBridge(std::string dir)117 void PreInitializeNativeBridge(std::string dir) {
118   VLOG(startup) << "Runtime::Pre-initialize native bridge";
119 #ifndef __APPLE__  // Mac OS does not support CLONE_NEWNS.
120   if (unshare(CLONE_NEWNS) == -1) {
121     LOG(WARNING) << "Could not create mount namespace.";
122   }
123   android::PreInitializeNativeBridge(dir.c_str(), GetInstructionSetString(kRuntimeISA));
124 #endif
125 }
126 
InitializeNativeBridge(JNIEnv * env,const char * instruction_set)127 void InitializeNativeBridge(JNIEnv* env, const char* instruction_set) {
128   android::InitializeNativeBridge(env, instruction_set);
129 }
130 
UnloadNativeBridge()131 void UnloadNativeBridge() {
132   android::UnloadNativeBridge();
133 }
134 
135 };  // namespace art
136