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 "gc/task_processor.h"
21 #include "jni_internal.h"
22 #include "nth_caller_visitor.h"
23 #include "mirror/class-inl.h"
24 #include "mirror/class_loader.h"
25 #include "mirror/object-inl.h"
26 #include "scoped_fast_native_object_access-inl.h"
27 #include "scoped_thread_state_change-inl.h"
28 #include "thread_list.h"
29
30 namespace art {
31
GetThreadStack(const ScopedFastNativeObjectAccess & soa,jobject peer)32 static jobject GetThreadStack(const ScopedFastNativeObjectAccess& soa, jobject peer)
33 REQUIRES_SHARED(Locks::mutator_lock_) {
34 jobject trace = nullptr;
35 ObjPtr<mirror::Object> decoded_peer = soa.Decode<mirror::Object>(peer);
36 if (decoded_peer == soa.Self()->GetPeer()) {
37 trace = soa.Self()->CreateInternalStackTrace<false>(soa);
38 } else {
39 // Never allow suspending the heap task thread since it may deadlock if allocations are
40 // required for the stack trace.
41 Thread* heap_task_thread =
42 Runtime::Current()->GetHeap()->GetTaskProcessor()->GetRunningThread();
43 // heap_task_thread could be null if the daemons aren't yet started.
44 if (heap_task_thread != nullptr && decoded_peer == heap_task_thread->GetPeerFromOtherThread()) {
45 return nullptr;
46 }
47 // Suspend thread to build stack trace.
48 ScopedThreadSuspension sts(soa.Self(), kNative);
49 ThreadList* thread_list = Runtime::Current()->GetThreadList();
50 bool timed_out;
51 Thread* thread = thread_list->SuspendThreadByPeer(peer, true, false, &timed_out);
52 if (thread != nullptr) {
53 // Must be runnable to create returned array.
54 {
55 ScopedObjectAccess soa2(soa.Self());
56 trace = thread->CreateInternalStackTrace<false>(soa);
57 }
58 // Restart suspended thread.
59 thread_list->Resume(thread, false);
60 } else if (timed_out) {
61 LOG(ERROR) << "Trying to get thread's stack failed as the thread failed to suspend within a "
62 "generous timeout.";
63 }
64 }
65 return trace;
66 }
67
VMStack_fillStackTraceElements(JNIEnv * env,jclass,jobject javaThread,jobjectArray javaSteArray)68 static jint VMStack_fillStackTraceElements(JNIEnv* env, jclass, jobject javaThread,
69 jobjectArray javaSteArray) {
70 ScopedFastNativeObjectAccess soa(env);
71 jobject trace = GetThreadStack(soa, javaThread);
72 if (trace == nullptr) {
73 return 0;
74 }
75 int32_t depth;
76 Thread::InternalStackTraceToStackTraceElementArray(soa, trace, javaSteArray, &depth);
77 return depth;
78 }
79
80 // Returns the defining class loader of the caller's caller.
VMStack_getCallingClassLoader(JNIEnv * env,jclass)81 static jobject VMStack_getCallingClassLoader(JNIEnv* env, jclass) {
82 ScopedFastNativeObjectAccess soa(env);
83 NthCallerVisitor visitor(soa.Self(), 2);
84 visitor.WalkStack();
85 if (UNLIKELY(visitor.caller == nullptr)) {
86 // The caller is an attached native thread.
87 return nullptr;
88 }
89 return soa.AddLocalReference<jobject>(visitor.caller->GetDeclaringClass()->GetClassLoader());
90 }
91
VMStack_getClosestUserClassLoader(JNIEnv * env,jclass)92 static jobject VMStack_getClosestUserClassLoader(JNIEnv* env, jclass) {
93 struct ClosestUserClassLoaderVisitor : public StackVisitor {
94 explicit ClosestUserClassLoaderVisitor(Thread* thread)
95 : StackVisitor(thread, nullptr, StackVisitor::StackWalkKind::kIncludeInlinedFrames),
96 class_loader(nullptr) {}
97
98 bool VisitFrame() REQUIRES_SHARED(Locks::mutator_lock_) {
99 DCHECK(class_loader == nullptr);
100 ObjPtr<mirror::Class> c = GetMethod()->GetDeclaringClass();
101 // c is null for runtime methods.
102 if (c != nullptr) {
103 ObjPtr<mirror::Object> cl = c->GetClassLoader();
104 if (cl != nullptr) {
105 class_loader = cl;
106 return false;
107 }
108 }
109 return true;
110 }
111
112 ObjPtr<mirror::Object> class_loader;
113 };
114 ScopedFastNativeObjectAccess soa(env);
115 ClosestUserClassLoaderVisitor visitor(soa.Self());
116 visitor.WalkStack();
117 return soa.AddLocalReference<jobject>(visitor.class_loader);
118 }
119
120 // Returns the class of the caller's caller's caller.
VMStack_getStackClass2(JNIEnv * env,jclass)121 static jclass VMStack_getStackClass2(JNIEnv* env, jclass) {
122 ScopedFastNativeObjectAccess soa(env);
123 NthCallerVisitor visitor(soa.Self(), 3);
124 visitor.WalkStack();
125 if (UNLIKELY(visitor.caller == nullptr)) {
126 // The caller is an attached native thread.
127 return nullptr;
128 }
129 return soa.AddLocalReference<jclass>(visitor.caller->GetDeclaringClass());
130 }
131
VMStack_getThreadStackTrace(JNIEnv * env,jclass,jobject javaThread)132 static jobjectArray VMStack_getThreadStackTrace(JNIEnv* env, jclass, jobject javaThread) {
133 ScopedFastNativeObjectAccess soa(env);
134 jobject trace = GetThreadStack(soa, javaThread);
135 if (trace == nullptr) {
136 return nullptr;
137 }
138 return Thread::InternalStackTraceToStackTraceElementArray(soa, trace);
139 }
140
141 static JNINativeMethod gMethods[] = {
142 FAST_NATIVE_METHOD(VMStack, fillStackTraceElements, "(Ljava/lang/Thread;[Ljava/lang/StackTraceElement;)I"),
143 FAST_NATIVE_METHOD(VMStack, getCallingClassLoader, "()Ljava/lang/ClassLoader;"),
144 FAST_NATIVE_METHOD(VMStack, getClosestUserClassLoader, "()Ljava/lang/ClassLoader;"),
145 FAST_NATIVE_METHOD(VMStack, getStackClass2, "()Ljava/lang/Class;"),
146 FAST_NATIVE_METHOD(VMStack, getThreadStackTrace, "(Ljava/lang/Thread;)[Ljava/lang/StackTraceElement;"),
147 };
148
register_dalvik_system_VMStack(JNIEnv * env)149 void register_dalvik_system_VMStack(JNIEnv* env) {
150 REGISTER_NATIVE_METHODS("dalvik/system/VMStack");
151 }
152
153 } // namespace art
154