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