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/*
* Copyright (C) 2008 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "dalvik_system_VMStack.h"
#include "nativehelper/jni_macros.h"
#include "art_method-inl.h"
#include "gc/task_processor.h"
#include "jni_internal.h"
#include "nth_caller_visitor.h"
#include "mirror/class-inl.h"
#include "mirror/class_loader.h"
#include "mirror/object-inl.h"
#include "native_util.h"
#include "scoped_fast_native_object_access-inl.h"
#include "scoped_thread_state_change-inl.h"
#include "thread_list.h"
namespace art {
static jobject GetThreadStack(const ScopedFastNativeObjectAccess& soa, jobject peer)
REQUIRES_SHARED(Locks::mutator_lock_) {
jobject trace = nullptr;
ObjPtr<mirror::Object> decoded_peer = soa.Decode<mirror::Object>(peer);
if (decoded_peer == soa.Self()->GetPeer()) {
trace = soa.Self()->CreateInternalStackTrace<false>(soa);
} else {
// Never allow suspending the heap task thread since it may deadlock if allocations are
// required for the stack trace.
Thread* heap_task_thread =
Runtime::Current()->GetHeap()->GetTaskProcessor()->GetRunningThread();
// heap_task_thread could be null if the daemons aren't yet started.
if (heap_task_thread != nullptr && decoded_peer == heap_task_thread->GetPeerFromOtherThread()) {
return nullptr;
}
// Suspend thread to build stack trace.
ScopedThreadSuspension sts(soa.Self(), kNative);
ThreadList* thread_list = Runtime::Current()->GetThreadList();
bool timed_out;
Thread* thread = thread_list->SuspendThreadByPeer(peer,
/* request_suspension */ true,
SuspendReason::kInternal,
&timed_out);
if (thread != nullptr) {
// Must be runnable to create returned array.
{
ScopedObjectAccess soa2(soa.Self());
trace = thread->CreateInternalStackTrace<false>(soa);
}
// Restart suspended thread.
bool resumed = thread_list->Resume(thread, SuspendReason::kInternal);
DCHECK(resumed);
} else if (timed_out) {
LOG(ERROR) << "Trying to get thread's stack failed as the thread failed to suspend within a "
"generous timeout.";
}
}
return trace;
}
static jint VMStack_fillStackTraceElements(JNIEnv* env, jclass, jobject javaThread,
jobjectArray javaSteArray) {
ScopedFastNativeObjectAccess soa(env);
jobject trace = GetThreadStack(soa, javaThread);
if (trace == nullptr) {
return 0;
}
int32_t depth;
Thread::InternalStackTraceToStackTraceElementArray(soa, trace, javaSteArray, &depth);
return depth;
}
// Returns the defining class loader of the caller's caller.
static jobject VMStack_getCallingClassLoader(JNIEnv* env, jclass) {
ScopedFastNativeObjectAccess soa(env);
NthCallerVisitor visitor(soa.Self(), 2);
visitor.WalkStack();
if (UNLIKELY(visitor.caller == nullptr)) {
// The caller is an attached native thread.
return nullptr;
}
return soa.AddLocalReference<jobject>(visitor.caller->GetDeclaringClass()->GetClassLoader());
}
static jobject VMStack_getClosestUserClassLoader(JNIEnv* env, jclass) {
struct ClosestUserClassLoaderVisitor : public StackVisitor {
explicit ClosestUserClassLoaderVisitor(Thread* thread)
: StackVisitor(thread, nullptr, StackVisitor::StackWalkKind::kIncludeInlinedFrames),
class_loader(nullptr) {}
bool VisitFrame() REQUIRES_SHARED(Locks::mutator_lock_) {
DCHECK(class_loader == nullptr);
ObjPtr<mirror::Class> c = GetMethod()->GetDeclaringClass();
// c is null for runtime methods.
if (c != nullptr) {
ObjPtr<mirror::Object> cl = c->GetClassLoader();
if (cl != nullptr) {
class_loader = cl;
return false;
}
}
return true;
}
ObjPtr<mirror::Object> class_loader;
};
ScopedFastNativeObjectAccess soa(env);
ClosestUserClassLoaderVisitor visitor(soa.Self());
visitor.WalkStack();
return soa.AddLocalReference<jobject>(visitor.class_loader);
}
// Returns the class of the caller's caller's caller.
static jclass VMStack_getStackClass2(JNIEnv* env, jclass) {
ScopedFastNativeObjectAccess soa(env);
NthCallerVisitor visitor(soa.Self(), 3);
visitor.WalkStack();
if (UNLIKELY(visitor.caller == nullptr)) {
// The caller is an attached native thread.
return nullptr;
}
return soa.AddLocalReference<jclass>(visitor.caller->GetDeclaringClass());
}
static jobjectArray VMStack_getThreadStackTrace(JNIEnv* env, jclass, jobject javaThread) {
ScopedFastNativeObjectAccess soa(env);
jobject trace = GetThreadStack(soa, javaThread);
if (trace == nullptr) {
return nullptr;
}
return Thread::InternalStackTraceToStackTraceElementArray(soa, trace);
}
static JNINativeMethod gMethods[] = {
FAST_NATIVE_METHOD(VMStack, fillStackTraceElements, "(Ljava/lang/Thread;[Ljava/lang/StackTraceElement;)I"),
FAST_NATIVE_METHOD(VMStack, getCallingClassLoader, "()Ljava/lang/ClassLoader;"),
FAST_NATIVE_METHOD(VMStack, getClosestUserClassLoader, "()Ljava/lang/ClassLoader;"),
FAST_NATIVE_METHOD(VMStack, getStackClass2, "()Ljava/lang/Class;"),
FAST_NATIVE_METHOD(VMStack, getThreadStackTrace, "(Ljava/lang/Thread;)[Ljava/lang/StackTraceElement;"),
};
void register_dalvik_system_VMStack(JNIEnv* env) {
REGISTER_NATIVE_METHODS("dalvik/system/VMStack");
}
} // namespace art
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