1 /*
2 * Copyright (C) 2008 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 "jni_internal.h"
18 #include "nth_caller_visitor.h"
19 #include "mirror/art_method-inl.h"
20 #include "mirror/class-inl.h"
21 #include "mirror/class_loader.h"
22 #include "mirror/object-inl.h"
23 #include "scoped_fast_native_object_access.h"
24 #include "scoped_thread_state_change.h"
25 #include "thread_list.h"
26
27 namespace art {
28
GetThreadStack(const ScopedFastNativeObjectAccess & soa,jobject peer)29 static jobject GetThreadStack(const ScopedFastNativeObjectAccess& soa, jobject peer)
30 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
31 jobject trace = nullptr;
32 if (soa.Decode<mirror::Object*>(peer) == soa.Self()->GetPeer()) {
33 trace = soa.Self()->CreateInternalStackTrace<false>(soa);
34 } else {
35 // Suspend thread to build stack trace.
36 soa.Self()->TransitionFromRunnableToSuspended(kNative);
37 ThreadList* thread_list = Runtime::Current()->GetThreadList();
38 bool timed_out;
39 Thread* thread;
40 {
41 // Take suspend thread lock to avoid races with threads trying to suspend this one.
42 MutexLock mu(soa.Self(), *Locks::thread_list_suspend_thread_lock_);
43 thread = thread_list->SuspendThreadByPeer(peer, true, false, &timed_out);
44 }
45 if (thread != nullptr) {
46 // Must be runnable to create returned array.
47 CHECK_EQ(soa.Self()->TransitionFromSuspendedToRunnable(), kNative);
48 trace = thread->CreateInternalStackTrace<false>(soa);
49 soa.Self()->TransitionFromRunnableToSuspended(kNative);
50 // Restart suspended thread.
51 thread_list->Resume(thread, false);
52 } else {
53 if (timed_out) {
54 LOG(ERROR) << "Trying to get thread's stack failed as the thread failed to suspend within a "
55 "generous timeout.";
56 }
57 }
58 CHECK_EQ(soa.Self()->TransitionFromSuspendedToRunnable(), kNative);
59 }
60 return trace;
61 }
62
VMStack_fillStackTraceElements(JNIEnv * env,jclass,jobject javaThread,jobjectArray javaSteArray)63 static jint VMStack_fillStackTraceElements(JNIEnv* env, jclass, jobject javaThread,
64 jobjectArray javaSteArray) {
65 ScopedFastNativeObjectAccess soa(env);
66 jobject trace = GetThreadStack(soa, javaThread);
67 if (trace == nullptr) {
68 return 0;
69 }
70 int32_t depth;
71 Thread::InternalStackTraceToStackTraceElementArray(soa, trace, javaSteArray, &depth);
72 return depth;
73 }
74
75 // Returns the defining class loader of the caller's caller.
VMStack_getCallingClassLoader(JNIEnv * env,jclass)76 static jobject VMStack_getCallingClassLoader(JNIEnv* env, jclass) {
77 ScopedFastNativeObjectAccess soa(env);
78 NthCallerVisitor visitor(soa.Self(), 2);
79 visitor.WalkStack();
80 if (UNLIKELY(visitor.caller == nullptr)) {
81 // The caller is an attached native thread.
82 return nullptr;
83 }
84 return soa.AddLocalReference<jobject>(visitor.caller->GetDeclaringClass()->GetClassLoader());
85 }
86
VMStack_getClosestUserClassLoader(JNIEnv * env,jclass,jobject javaBootstrap,jobject javaSystem)87 static jobject VMStack_getClosestUserClassLoader(JNIEnv* env, jclass, jobject javaBootstrap,
88 jobject javaSystem) {
89 struct ClosestUserClassLoaderVisitor : public StackVisitor {
90 ClosestUserClassLoaderVisitor(Thread* thread, mirror::Object* bootstrap, mirror::Object* system)
91 : StackVisitor(thread, NULL), bootstrap(bootstrap), system(system), class_loader(NULL) {}
92
93 bool VisitFrame() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
94 DCHECK(class_loader == NULL);
95 mirror::Class* c = GetMethod()->GetDeclaringClass();
96 mirror::Object* cl = c->GetClassLoader();
97 if (cl != NULL && cl != bootstrap && cl != system) {
98 class_loader = cl;
99 return false;
100 }
101 return true;
102 }
103
104 mirror::Object* bootstrap;
105 mirror::Object* system;
106 mirror::Object* class_loader;
107 };
108 ScopedFastNativeObjectAccess soa(env);
109 mirror::Object* bootstrap = soa.Decode<mirror::Object*>(javaBootstrap);
110 mirror::Object* system = soa.Decode<mirror::Object*>(javaSystem);
111 ClosestUserClassLoaderVisitor visitor(soa.Self(), bootstrap, system);
112 visitor.WalkStack();
113 return soa.AddLocalReference<jobject>(visitor.class_loader);
114 }
115
116 // Returns the class of the caller's caller's caller.
VMStack_getStackClass2(JNIEnv * env,jclass)117 static jclass VMStack_getStackClass2(JNIEnv* env, jclass) {
118 ScopedFastNativeObjectAccess soa(env);
119 NthCallerVisitor visitor(soa.Self(), 3);
120 visitor.WalkStack();
121 if (UNLIKELY(visitor.caller == nullptr)) {
122 // The caller is an attached native thread.
123 return nullptr;
124 }
125 return soa.AddLocalReference<jclass>(visitor.caller->GetDeclaringClass());
126 }
127
VMStack_getThreadStackTrace(JNIEnv * env,jclass,jobject javaThread)128 static jobjectArray VMStack_getThreadStackTrace(JNIEnv* env, jclass, jobject javaThread) {
129 ScopedFastNativeObjectAccess soa(env);
130 jobject trace = GetThreadStack(soa, javaThread);
131 if (trace == nullptr) {
132 return nullptr;
133 }
134 return Thread::InternalStackTraceToStackTraceElementArray(soa, trace);
135 }
136
137 static JNINativeMethod gMethods[] = {
138 NATIVE_METHOD(VMStack, fillStackTraceElements, "!(Ljava/lang/Thread;[Ljava/lang/StackTraceElement;)I"),
139 NATIVE_METHOD(VMStack, getCallingClassLoader, "!()Ljava/lang/ClassLoader;"),
140 NATIVE_METHOD(VMStack, getClosestUserClassLoader, "!(Ljava/lang/ClassLoader;Ljava/lang/ClassLoader;)Ljava/lang/ClassLoader;"),
141 NATIVE_METHOD(VMStack, getStackClass2, "!()Ljava/lang/Class;"),
142 NATIVE_METHOD(VMStack, getThreadStackTrace, "!(Ljava/lang/Thread;)[Ljava/lang/StackTraceElement;"),
143 };
144
register_dalvik_system_VMStack(JNIEnv * env)145 void register_dalvik_system_VMStack(JNIEnv* env) {
146 REGISTER_NATIVE_METHODS("dalvik/system/VMStack");
147 }
148
149 } // namespace art
150