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 <signal.h>
20
21 #include "nativebridge/native_bridge.h"
22
23 #include "art_method-inl.h"
24 #include "base/enums.h"
25 #include "base/logging.h" // For VLOG.
26 #include "base/macros.h"
27 #include "dex/dex_file-inl.h"
28 #include "jni/jni_internal.h"
29 #include "mirror/class-inl.h"
30 #include "scoped_thread_state_change-inl.h"
31 #include "sigchain.h"
32
33 namespace art {
34
GetMethodShorty(JNIEnv * env,jmethodID mid)35 static const char* GetMethodShorty(JNIEnv* env, jmethodID mid) {
36 ScopedObjectAccess soa(env);
37 ArtMethod* m = jni::DecodeArtMethod(mid);
38 return m->GetShorty();
39 }
40
GetNativeMethodCount(JNIEnv * env,jclass clazz)41 static uint32_t GetNativeMethodCount(JNIEnv* env, jclass clazz) {
42 if (clazz == nullptr) {
43 return 0;
44 }
45
46 ScopedObjectAccess soa(env);
47 ObjPtr<mirror::Class> c = soa.Decode<mirror::Class>(clazz);
48
49 uint32_t native_method_count = 0;
50 for (auto& m : c->GetMethods(kRuntimePointerSize)) {
51 native_method_count += m.IsNative() ? 1u : 0u;
52 }
53 return native_method_count;
54 }
55
GetNativeMethods(JNIEnv * env,jclass clazz,JNINativeMethod * methods,uint32_t method_count)56 static uint32_t GetNativeMethods(JNIEnv* env, jclass clazz, JNINativeMethod* methods,
57 uint32_t method_count) {
58 if ((clazz == nullptr) || (methods == nullptr)) {
59 return 0;
60 }
61 ScopedObjectAccess soa(env);
62 ObjPtr<mirror::Class> c = soa.Decode<mirror::Class>(clazz);
63
64 uint32_t count = 0;
65 for (auto& m : c->GetMethods(kRuntimePointerSize)) {
66 if (m.IsNative()) {
67 if (count < method_count) {
68 methods[count].name = m.GetName();
69 methods[count].signature = m.GetShorty();
70 methods[count].fnPtr = m.GetEntryPointFromJni();
71 count++;
72 } else {
73 LOG(WARNING) << "Output native method array too small. Skipping "
74 << m.PrettyMethod();
75 }
76 }
77 }
78 return count;
79 }
80
81 // Native bridge library runtime callbacks. They represent the runtime interface to native bridge.
82 //
83 // The interface is expected to expose the following methods:
84 // getMethodShorty(): in the case of native method calling JNI native function CallXXXXMethodY(),
85 // native bridge calls back to VM for the shorty of the method so that it can prepare based on
86 // host calling convention.
87 // getNativeMethodCount() and getNativeMethods(): in case of JNI function UnregisterNatives(),
88 // native bridge can call back to get all native methods of specified class so that all
89 // corresponding trampolines can be destroyed.
90 static android::NativeBridgeRuntimeCallbacks native_bridge_art_callbacks_ {
91 GetMethodShorty, GetNativeMethodCount, GetNativeMethods
92 };
93
LoadNativeBridge(const std::string & native_bridge_library_filename)94 bool LoadNativeBridge(const std::string& native_bridge_library_filename) {
95 VLOG(startup) << "Runtime::Setup native bridge library: "
96 << (native_bridge_library_filename.empty() ? "(empty)" : native_bridge_library_filename);
97 return android::LoadNativeBridge(native_bridge_library_filename.c_str(),
98 &native_bridge_art_callbacks_);
99 }
100
PreInitializeNativeBridge(const std::string & dir)101 void PreInitializeNativeBridge(const std::string& dir) {
102 VLOG(startup) << "Runtime::Pre-initialize native bridge";
103 #ifndef __APPLE__ // Mac OS does not support CLONE_NEWNS.
104 if (unshare(CLONE_NEWNS) == -1) {
105 LOG(WARNING) << "Could not create mount namespace.";
106 }
107 android::PreInitializeNativeBridge(dir.c_str(), GetInstructionSetString(kRuntimeISA));
108 #else
109 UNUSED(dir);
110 #endif
111 }
112
InitializeNativeBridge(JNIEnv * env,const char * instruction_set)113 void InitializeNativeBridge(JNIEnv* env, const char* instruction_set) {
114 if (android::InitializeNativeBridge(env, instruction_set)) {
115 if (android::NativeBridgeGetVersion() >= 2U) {
116 #ifdef _NSIG // Undefined on Apple, but we don't support running on Mac, anyways.
117 // Managed signal handling support added in version 2.
118 for (int signal = 0; signal < _NSIG; ++signal) {
119 android::NativeBridgeSignalHandlerFn fn = android::NativeBridgeGetSignalHandler(signal);
120 if (fn != nullptr) {
121 sigset_t mask;
122 sigfillset(&mask);
123 SigchainAction sa = {
124 .sc_sigaction = fn,
125 .sc_mask = mask,
126 // The native bridge signal might not return back to sigchain's handler.
127 .sc_flags = SIGCHAIN_ALLOW_NORETURN,
128 };
129 AddSpecialSignalHandlerFn(signal, &sa);
130 }
131 }
132 #endif
133 }
134 }
135 }
136
UnloadNativeBridge()137 void UnloadNativeBridge() {
138 android::UnloadNativeBridge();
139 }
140
141 } // namespace art
142