| /* Copyright (C) 2017 The Android Open Source Project |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This file implements interfaces from the file jvmti.h. This implementation |
| * is licensed under the same terms as the file jvmti.h. The |
| * copyright and license information for the file jvmti.h follows. |
| * |
| * Copyright (c) 2003, 2011, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| #include "ti_thread.h" |
| |
| #include <android-base/logging.h> |
| #include <android-base/strings.h> |
| |
| #include "art_field-inl.h" |
| #include "art_jvmti.h" |
| #include "base/mutex.h" |
| #include "events-inl.h" |
| #include "gc/system_weak.h" |
| #include "gc/collector_type.h" |
| #include "gc/gc_cause.h" |
| #include "gc/scoped_gc_critical_section.h" |
| #include "gc_root-inl.h" |
| #include "jni/jni_internal.h" |
| #include "mirror/class.h" |
| #include "mirror/object-inl.h" |
| #include "mirror/string.h" |
| #include "nativehelper/scoped_local_ref.h" |
| #include "nativehelper/scoped_utf_chars.h" |
| #include "obj_ptr.h" |
| #include "runtime.h" |
| #include "runtime_callbacks.h" |
| #include "scoped_thread_state_change-inl.h" |
| #include "thread-current-inl.h" |
| #include "thread_list.h" |
| #include "ti_phase.h" |
| #include "well_known_classes.h" |
| |
| namespace openjdkjvmti { |
| |
| static const char* kJvmtiTlsKey = "JvmtiTlsKey"; |
| |
| art::ArtField* ThreadUtil::context_class_loader_ = nullptr; |
| |
| struct ThreadCallback : public art::ThreadLifecycleCallback { |
| jthread GetThreadObject(art::Thread* self) REQUIRES_SHARED(art::Locks::mutator_lock_) { |
| if (self->GetPeer() == nullptr) { |
| return nullptr; |
| } |
| return self->GetJniEnv()->AddLocalReference<jthread>(self->GetPeer()); |
| } |
| |
| template <ArtJvmtiEvent kEvent> |
| void Post(art::Thread* self) REQUIRES_SHARED(art::Locks::mutator_lock_) { |
| DCHECK_EQ(self, art::Thread::Current()); |
| ScopedLocalRef<jthread> thread(self->GetJniEnv(), GetThreadObject(self)); |
| art::ScopedThreadSuspension sts(self, art::ThreadState::kNative); |
| event_handler->DispatchEvent<kEvent>(self, |
| reinterpret_cast<JNIEnv*>(self->GetJniEnv()), |
| thread.get()); |
| } |
| |
| void ThreadStart(art::Thread* self) override REQUIRES_SHARED(art::Locks::mutator_lock_) { |
| if (!started) { |
| // Runtime isn't started. We only expect at most the signal handler or JIT threads to be |
| // started here. |
| if (art::kIsDebugBuild) { |
| std::string name; |
| self->GetThreadName(name); |
| if (name != "JDWP" && |
| name != "Signal Catcher" && |
| !android::base::StartsWith(name, "Jit thread pool")) { |
| LOG(FATAL) << "Unexpected thread before start: " << name << " id: " |
| << self->GetThreadId(); |
| } |
| } |
| return; |
| } |
| Post<ArtJvmtiEvent::kThreadStart>(self); |
| } |
| |
| void ThreadDeath(art::Thread* self) override REQUIRES_SHARED(art::Locks::mutator_lock_) { |
| Post<ArtJvmtiEvent::kThreadEnd>(self); |
| } |
| |
| EventHandler* event_handler = nullptr; |
| bool started = false; |
| }; |
| |
| ThreadCallback gThreadCallback; |
| |
| void ThreadUtil::Register(EventHandler* handler) { |
| art::Runtime* runtime = art::Runtime::Current(); |
| |
| gThreadCallback.started = runtime->IsStarted(); |
| gThreadCallback.event_handler = handler; |
| |
| art::ScopedThreadStateChange stsc(art::Thread::Current(), |
| art::ThreadState::kWaitingForDebuggerToAttach); |
| art::ScopedSuspendAll ssa("Add thread callback"); |
| runtime->GetRuntimeCallbacks()->AddThreadLifecycleCallback(&gThreadCallback); |
| } |
| |
| void ThreadUtil::VMInitEventSent() { |
| // We should have already started. |
| DCHECK(gThreadCallback.started); |
| // We moved to VMInit. Report the main thread as started (it was attached early, and must not be |
| // reported until Init. |
| gThreadCallback.Post<ArtJvmtiEvent::kThreadStart>(art::Thread::Current()); |
| } |
| |
| void ThreadUtil::CacheData() { |
| // We must have started since it is now safe to cache our data; |
| gThreadCallback.started = true; |
| art::ScopedObjectAccess soa(art::Thread::Current()); |
| art::ObjPtr<art::mirror::Class> thread_class = |
| soa.Decode<art::mirror::Class>(art::WellKnownClasses::java_lang_Thread); |
| CHECK(thread_class != nullptr); |
| context_class_loader_ = thread_class->FindDeclaredInstanceField("contextClassLoader", |
| "Ljava/lang/ClassLoader;"); |
| CHECK(context_class_loader_ != nullptr); |
| } |
| |
| void ThreadUtil::Unregister() { |
| art::ScopedThreadStateChange stsc(art::Thread::Current(), |
| art::ThreadState::kWaitingForDebuggerToAttach); |
| art::ScopedSuspendAll ssa("Remove thread callback"); |
| art::Runtime* runtime = art::Runtime::Current(); |
| runtime->GetRuntimeCallbacks()->RemoveThreadLifecycleCallback(&gThreadCallback); |
| } |
| |
| jvmtiError ThreadUtil::GetCurrentThread(jvmtiEnv* env ATTRIBUTE_UNUSED, jthread* thread_ptr) { |
| art::Thread* self = art::Thread::Current(); |
| |
| art::ScopedObjectAccess soa(self); |
| |
| jthread thread_peer; |
| if (self->IsStillStarting()) { |
| thread_peer = nullptr; |
| } else { |
| thread_peer = soa.AddLocalReference<jthread>(self->GetPeer()); |
| } |
| |
| *thread_ptr = thread_peer; |
| return ERR(NONE); |
| } |
| |
| // Get the native thread. The spec says a null object denotes the current thread. |
| bool ThreadUtil::GetNativeThread(jthread thread, |
| const art::ScopedObjectAccessAlreadyRunnable& soa, |
| /*out*/ art::Thread** thr, |
| /*out*/ jvmtiError* err) { |
| if (thread == nullptr) { |
| *thr = art::Thread::Current(); |
| return true; |
| } else if (!soa.Env()->IsInstanceOf(thread, art::WellKnownClasses::java_lang_Thread)) { |
| *err = ERR(INVALID_THREAD); |
| return false; |
| } else { |
| *thr = art::Thread::FromManagedThread(soa, thread); |
| return true; |
| } |
| } |
| |
| bool ThreadUtil::GetAliveNativeThread(jthread thread, |
| const art::ScopedObjectAccessAlreadyRunnable& soa, |
| /*out*/ art::Thread** thr, |
| /*out*/ jvmtiError* err) { |
| if (!GetNativeThread(thread, soa, thr, err)) { |
| return false; |
| } else if (*thr == nullptr || (*thr)->GetState() == art::ThreadState::kTerminated) { |
| *err = ERR(THREAD_NOT_ALIVE); |
| return false; |
| } else { |
| return true; |
| } |
| } |
| |
| jvmtiError ThreadUtil::GetThreadInfo(jvmtiEnv* env, jthread thread, jvmtiThreadInfo* info_ptr) { |
| if (info_ptr == nullptr) { |
| return ERR(NULL_POINTER); |
| } |
| if (!PhaseUtil::IsLivePhase()) { |
| return JVMTI_ERROR_WRONG_PHASE; |
| } |
| |
| art::Thread* self = art::Thread::Current(); |
| art::ScopedObjectAccess soa(self); |
| art::MutexLock mu(self, *art::Locks::thread_list_lock_); |
| |
| art::Thread* target; |
| jvmtiError err = ERR(INTERNAL); |
| if (!GetNativeThread(thread, soa, &target, &err)) { |
| return err; |
| } |
| |
| JvmtiUniquePtr<char[]> name_uptr; |
| if (target != nullptr) { |
| // Have a native thread object, this thread is alive. |
| std::string name; |
| target->GetThreadName(name); |
| jvmtiError name_result; |
| name_uptr = CopyString(env, name.c_str(), &name_result); |
| if (name_uptr == nullptr) { |
| return name_result; |
| } |
| info_ptr->name = name_uptr.get(); |
| |
| info_ptr->priority = target->GetNativePriority(); |
| |
| info_ptr->is_daemon = target->IsDaemon(); |
| |
| art::ObjPtr<art::mirror::Object> peer = target->GetPeerFromOtherThread(); |
| |
| // ThreadGroup. |
| if (peer != nullptr) { |
| art::ArtField* f = art::jni::DecodeArtField(art::WellKnownClasses::java_lang_Thread_group); |
| CHECK(f != nullptr); |
| art::ObjPtr<art::mirror::Object> group = f->GetObject(peer); |
| info_ptr->thread_group = group == nullptr |
| ? nullptr |
| : soa.AddLocalReference<jthreadGroup>(group); |
| } else { |
| info_ptr->thread_group = nullptr; |
| } |
| |
| // Context classloader. |
| DCHECK(context_class_loader_ != nullptr); |
| art::ObjPtr<art::mirror::Object> ccl = peer != nullptr |
| ? context_class_loader_->GetObject(peer) |
| : nullptr; |
| info_ptr->context_class_loader = ccl == nullptr |
| ? nullptr |
| : soa.AddLocalReference<jobject>(ccl); |
| } else { |
| // Only the peer. This thread has either not been started, or is dead. Read things from |
| // the Java side. |
| art::ObjPtr<art::mirror::Object> peer = soa.Decode<art::mirror::Object>(thread); |
| |
| // Name. |
| { |
| art::ArtField* f = art::jni::DecodeArtField(art::WellKnownClasses::java_lang_Thread_name); |
| CHECK(f != nullptr); |
| art::ObjPtr<art::mirror::Object> name = f->GetObject(peer); |
| std::string name_cpp; |
| const char* name_cstr; |
| if (name != nullptr) { |
| name_cpp = name->AsString()->ToModifiedUtf8(); |
| name_cstr = name_cpp.c_str(); |
| } else { |
| name_cstr = ""; |
| } |
| jvmtiError name_result; |
| name_uptr = CopyString(env, name_cstr, &name_result); |
| if (name_uptr == nullptr) { |
| return name_result; |
| } |
| info_ptr->name = name_uptr.get(); |
| } |
| |
| // Priority. |
| { |
| art::ArtField* f = art::jni::DecodeArtField(art::WellKnownClasses::java_lang_Thread_priority); |
| CHECK(f != nullptr); |
| info_ptr->priority = static_cast<jint>(f->GetInt(peer)); |
| } |
| |
| // Daemon. |
| { |
| art::ArtField* f = art::jni::DecodeArtField(art::WellKnownClasses::java_lang_Thread_daemon); |
| CHECK(f != nullptr); |
| info_ptr->is_daemon = f->GetBoolean(peer) == 0 ? JNI_FALSE : JNI_TRUE; |
| } |
| |
| // ThreadGroup. |
| { |
| art::ArtField* f = art::jni::DecodeArtField(art::WellKnownClasses::java_lang_Thread_group); |
| CHECK(f != nullptr); |
| art::ObjPtr<art::mirror::Object> group = f->GetObject(peer); |
| info_ptr->thread_group = group == nullptr |
| ? nullptr |
| : soa.AddLocalReference<jthreadGroup>(group); |
| } |
| |
| // Context classloader. |
| DCHECK(context_class_loader_ != nullptr); |
| art::ObjPtr<art::mirror::Object> ccl = peer != nullptr |
| ? context_class_loader_->GetObject(peer) |
| : nullptr; |
| info_ptr->context_class_loader = ccl == nullptr |
| ? nullptr |
| : soa.AddLocalReference<jobject>(ccl); |
| } |
| |
| name_uptr.release(); |
| |
| return ERR(NONE); |
| } |
| |
| struct InternalThreadState { |
| art::Thread* native_thread; |
| art::ThreadState art_state; |
| int thread_user_code_suspend_count; |
| }; |
| |
| // Return the thread's (or current thread, if null) thread state. |
| static InternalThreadState GetNativeThreadState(art::Thread* target) |
| REQUIRES_SHARED(art::Locks::mutator_lock_) |
| REQUIRES(art::Locks::thread_list_lock_, art::Locks::user_code_suspension_lock_) { |
| InternalThreadState thread_state = {}; |
| art::MutexLock tscl_mu(art::Thread::Current(), *art::Locks::thread_suspend_count_lock_); |
| thread_state.native_thread = target; |
| if (target == nullptr || target->IsStillStarting()) { |
| thread_state.art_state = art::ThreadState::kStarting; |
| thread_state.thread_user_code_suspend_count = 0; |
| } else { |
| thread_state.art_state = target->GetState(); |
| thread_state.thread_user_code_suspend_count = target->GetUserCodeSuspendCount(); |
| } |
| return thread_state; |
| } |
| |
| static jint GetJvmtiThreadStateFromInternal(const InternalThreadState& state) { |
| art::ThreadState internal_thread_state = state.art_state; |
| jint jvmti_state = JVMTI_THREAD_STATE_ALIVE; |
| |
| if (state.thread_user_code_suspend_count != 0) { |
| // Suspended can be set with any thread state so check it here. Even if the thread isn't in |
| // kSuspended state it will move to that once it hits a checkpoint so we can still set this. |
| jvmti_state |= JVMTI_THREAD_STATE_SUSPENDED; |
| // Note: We do not have data about the previous state. Otherwise we should load the previous |
| // state here. |
| } |
| |
| if (state.native_thread->IsInterrupted()) { |
| // Interrupted can be set with any thread state so check it here. |
| jvmti_state |= JVMTI_THREAD_STATE_INTERRUPTED; |
| } |
| |
| // Enumerate all the thread states and fill in the other bits. This contains the results of |
| // following the decision tree in the JVMTI spec GetThreadState documentation. |
| switch (internal_thread_state) { |
| case art::ThreadState::kRunnable: |
| case art::ThreadState::kWaitingWeakGcRootRead: |
| case art::ThreadState::kSuspended: |
| // These are all simply runnable. |
| // kRunnable is self-explanatory. |
| // kWaitingWeakGcRootRead is set during some operations with strings due to the intern-table |
| // so we want to keep it marked as runnable. |
| // kSuspended we don't mark since if we don't have a user_code_suspend_count then it is done |
| // by the GC and not a JVMTI suspension, which means it cannot be removed by ResumeThread. |
| jvmti_state |= JVMTI_THREAD_STATE_RUNNABLE; |
| break; |
| case art::ThreadState::kNative: |
| // kNative means native and runnable. Technically THREAD_STATE_IN_NATIVE can be set with any |
| // state but we don't have the information to know if it should be present for any but the |
| // kNative state. |
| jvmti_state |= (JVMTI_THREAD_STATE_IN_NATIVE | |
| JVMTI_THREAD_STATE_RUNNABLE); |
| break; |
| case art::ThreadState::kBlocked: |
| // Blocked is one of the top level states so it sits alone. |
| jvmti_state |= JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER; |
| break; |
| case art::ThreadState::kWaiting: |
| // Object.wait() so waiting, indefinitely, in object.wait. |
| jvmti_state |= (JVMTI_THREAD_STATE_WAITING | |
| JVMTI_THREAD_STATE_WAITING_INDEFINITELY | |
| JVMTI_THREAD_STATE_IN_OBJECT_WAIT); |
| break; |
| case art::ThreadState::kTimedWaiting: |
| // Object.wait(long) so waiting, with timeout, in object.wait. |
| jvmti_state |= (JVMTI_THREAD_STATE_WAITING | |
| JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT | |
| JVMTI_THREAD_STATE_IN_OBJECT_WAIT); |
| break; |
| case art::ThreadState::kSleeping: |
| // In object.sleep. This is a timed wait caused by sleep. |
| jvmti_state |= (JVMTI_THREAD_STATE_WAITING | |
| JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT | |
| JVMTI_THREAD_STATE_SLEEPING); |
| break; |
| // TODO We might want to print warnings if we have the debugger running while JVMTI agents are |
| // attached. |
| case art::ThreadState::kWaitingForDebuggerSend: |
| case art::ThreadState::kWaitingForDebuggerToAttach: |
| case art::ThreadState::kWaitingInMainDebuggerLoop: |
| case art::ThreadState::kWaitingForDebuggerSuspension: |
| case art::ThreadState::kWaitingForLockInflation: |
| case art::ThreadState::kWaitingForTaskProcessor: |
| case art::ThreadState::kWaitingForGcToComplete: |
| case art::ThreadState::kWaitingForCheckPointsToRun: |
| case art::ThreadState::kWaitingPerformingGc: |
| case art::ThreadState::kWaitingForJniOnLoad: |
| case art::ThreadState::kWaitingInMainSignalCatcherLoop: |
| case art::ThreadState::kWaitingForSignalCatcherOutput: |
| case art::ThreadState::kWaitingForDeoptimization: |
| case art::ThreadState::kWaitingForMethodTracingStart: |
| case art::ThreadState::kWaitingForVisitObjects: |
| case art::ThreadState::kWaitingForGetObjectsAllocated: |
| case art::ThreadState::kWaitingForGcThreadFlip: |
| // All of these are causing the thread to wait for an indeterminate amount of time but isn't |
| // caused by sleep, park, or object#wait. |
| jvmti_state |= (JVMTI_THREAD_STATE_WAITING | |
| JVMTI_THREAD_STATE_WAITING_INDEFINITELY); |
| break; |
| case art::ThreadState::kStarting: |
| case art::ThreadState::kTerminated: |
| // We only call this if we are alive so we shouldn't see either of these states. |
| LOG(FATAL) << "Should not be in state " << internal_thread_state; |
| UNREACHABLE(); |
| } |
| // TODO: PARKED. We'll have to inspect the stack. |
| |
| return jvmti_state; |
| } |
| |
| static jint GetJavaStateFromInternal(const InternalThreadState& state) { |
| switch (state.art_state) { |
| case art::ThreadState::kTerminated: |
| return JVMTI_JAVA_LANG_THREAD_STATE_TERMINATED; |
| |
| case art::ThreadState::kRunnable: |
| case art::ThreadState::kNative: |
| case art::ThreadState::kWaitingWeakGcRootRead: |
| case art::ThreadState::kSuspended: |
| return JVMTI_JAVA_LANG_THREAD_STATE_RUNNABLE; |
| |
| case art::ThreadState::kTimedWaiting: |
| case art::ThreadState::kSleeping: |
| return JVMTI_JAVA_LANG_THREAD_STATE_TIMED_WAITING; |
| |
| case art::ThreadState::kBlocked: |
| return JVMTI_JAVA_LANG_THREAD_STATE_BLOCKED; |
| |
| case art::ThreadState::kStarting: |
| return JVMTI_JAVA_LANG_THREAD_STATE_NEW; |
| |
| case art::ThreadState::kWaiting: |
| case art::ThreadState::kWaitingForTaskProcessor: |
| case art::ThreadState::kWaitingForLockInflation: |
| case art::ThreadState::kWaitingForGcToComplete: |
| case art::ThreadState::kWaitingPerformingGc: |
| case art::ThreadState::kWaitingForCheckPointsToRun: |
| case art::ThreadState::kWaitingForDebuggerSend: |
| case art::ThreadState::kWaitingForDebuggerToAttach: |
| case art::ThreadState::kWaitingInMainDebuggerLoop: |
| case art::ThreadState::kWaitingForDebuggerSuspension: |
| case art::ThreadState::kWaitingForDeoptimization: |
| case art::ThreadState::kWaitingForGetObjectsAllocated: |
| case art::ThreadState::kWaitingForJniOnLoad: |
| case art::ThreadState::kWaitingForSignalCatcherOutput: |
| case art::ThreadState::kWaitingInMainSignalCatcherLoop: |
| case art::ThreadState::kWaitingForMethodTracingStart: |
| case art::ThreadState::kWaitingForVisitObjects: |
| case art::ThreadState::kWaitingForGcThreadFlip: |
| return JVMTI_JAVA_LANG_THREAD_STATE_WAITING; |
| } |
| LOG(FATAL) << "Unreachable"; |
| UNREACHABLE(); |
| } |
| |
| // Suspends the current thread if it has any suspend requests on it. |
| void ThreadUtil::SuspendCheck(art::Thread* self) { |
| art::ScopedObjectAccess soa(self); |
| // Really this is only needed if we are in FastJNI and actually have the mutator_lock_ already. |
| self->FullSuspendCheck(); |
| } |
| |
| bool ThreadUtil::WouldSuspendForUserCodeLocked(art::Thread* self) { |
| DCHECK(self == art::Thread::Current()); |
| art::MutexLock tscl_mu(self, *art::Locks::thread_suspend_count_lock_); |
| return self->GetUserCodeSuspendCount() != 0; |
| } |
| |
| bool ThreadUtil::WouldSuspendForUserCode(art::Thread* self) { |
| DCHECK(self == art::Thread::Current()); |
| art::MutexLock ucsl_mu(self, *art::Locks::user_code_suspension_lock_); |
| return WouldSuspendForUserCodeLocked(self); |
| } |
| |
| jvmtiError ThreadUtil::GetThreadState(jvmtiEnv* env ATTRIBUTE_UNUSED, |
| jthread thread, |
| jint* thread_state_ptr) { |
| if (thread_state_ptr == nullptr) { |
| return ERR(NULL_POINTER); |
| } |
| |
| art::Thread* self = art::Thread::Current(); |
| InternalThreadState state = {}; |
| // Loop since we need to bail out and try again if we would end up getting suspended while holding |
| // the user_code_suspension_lock_ due to a SuspendReason::kForUserCode. In this situation we |
| // release the lock, wait to get resumed and try again. |
| do { |
| SuspendCheck(self); |
| art::MutexLock ucsl_mu(self, *art::Locks::user_code_suspension_lock_); |
| if (WouldSuspendForUserCodeLocked(self)) { |
| // Make sure we won't be suspended in the middle of holding the thread_suspend_count_lock_ by |
| // a user-code suspension. We retry and do another SuspendCheck to clear this. |
| continue; |
| } |
| art::ScopedObjectAccess soa(self); |
| art::MutexLock tll_mu(self, *art::Locks::thread_list_lock_); |
| jvmtiError err = ERR(INTERNAL); |
| art::Thread* target = nullptr; |
| if (!GetNativeThread(thread, soa, &target, &err)) { |
| return err; |
| } |
| state = GetNativeThreadState(target); |
| if (state.art_state == art::ThreadState::kStarting) { |
| break; |
| } |
| DCHECK(state.native_thread != nullptr); |
| |
| // Translate internal thread state to JVMTI and Java state. |
| jint jvmti_state = GetJvmtiThreadStateFromInternal(state); |
| |
| // Java state is derived from nativeGetState. |
| // TODO: Our implementation assigns "runnable" to suspended. As such, we will have slightly |
| // different mask if a thread got suspended due to user-code. However, this is for |
| // consistency with the Java view. |
| jint java_state = GetJavaStateFromInternal(state); |
| |
| *thread_state_ptr = jvmti_state | java_state; |
| |
| return ERR(NONE); |
| } while (true); |
| |
| DCHECK_EQ(state.art_state, art::ThreadState::kStarting); |
| |
| if (thread == nullptr) { |
| // No native thread, and no Java thread? We must be starting up. Report as wrong phase. |
| return ERR(WRONG_PHASE); |
| } |
| |
| art::ScopedObjectAccess soa(self); |
| art::StackHandleScope<1> hs(self); |
| |
| // Need to read the Java "started" field to know whether this is starting or terminated. |
| art::Handle<art::mirror::Object> peer(hs.NewHandle(soa.Decode<art::mirror::Object>(thread))); |
| art::ObjPtr<art::mirror::Class> thread_klass = |
| soa.Decode<art::mirror::Class>(art::WellKnownClasses::java_lang_Thread); |
| if (!thread_klass->IsAssignableFrom(peer->GetClass())) { |
| return ERR(INVALID_THREAD); |
| } |
| art::ArtField* started_field = thread_klass->FindDeclaredInstanceField("started", "Z"); |
| CHECK(started_field != nullptr); |
| bool started = started_field->GetBoolean(peer.Get()) != 0; |
| constexpr jint kStartedState = JVMTI_JAVA_LANG_THREAD_STATE_NEW; |
| constexpr jint kTerminatedState = JVMTI_THREAD_STATE_TERMINATED | |
| JVMTI_JAVA_LANG_THREAD_STATE_TERMINATED; |
| *thread_state_ptr = started ? kTerminatedState : kStartedState; |
| return ERR(NONE); |
| } |
| |
| jvmtiError ThreadUtil::GetAllThreads(jvmtiEnv* env, |
| jint* threads_count_ptr, |
| jthread** threads_ptr) { |
| if (threads_count_ptr == nullptr || threads_ptr == nullptr) { |
| return ERR(NULL_POINTER); |
| } |
| |
| art::Thread* current = art::Thread::Current(); |
| |
| art::ScopedObjectAccess soa(current); |
| |
| art::MutexLock mu(current, *art::Locks::thread_list_lock_); |
| std::list<art::Thread*> thread_list = art::Runtime::Current()->GetThreadList()->GetList(); |
| |
| std::vector<art::ObjPtr<art::mirror::Object>> peers; |
| |
| for (art::Thread* thread : thread_list) { |
| // Skip threads that are still starting. |
| if (thread->IsStillStarting()) { |
| continue; |
| } |
| |
| art::ObjPtr<art::mirror::Object> peer = thread->GetPeerFromOtherThread(); |
| if (peer != nullptr) { |
| peers.push_back(peer); |
| } |
| } |
| |
| if (peers.empty()) { |
| *threads_count_ptr = 0; |
| *threads_ptr = nullptr; |
| } else { |
| unsigned char* data; |
| jvmtiError data_result = env->Allocate(peers.size() * sizeof(jthread), &data); |
| if (data_result != ERR(NONE)) { |
| return data_result; |
| } |
| jthread* threads = reinterpret_cast<jthread*>(data); |
| for (size_t i = 0; i != peers.size(); ++i) { |
| threads[i] = soa.AddLocalReference<jthread>(peers[i]); |
| } |
| |
| *threads_count_ptr = static_cast<jint>(peers.size()); |
| *threads_ptr = threads; |
| } |
| return ERR(NONE); |
| } |
| |
| static void RemoveTLSData(art::Thread* target, void* ctx) REQUIRES(art::Locks::thread_list_lock_) { |
| jvmtiEnv* env = reinterpret_cast<jvmtiEnv*>(ctx); |
| art::Locks::thread_list_lock_->AssertHeld(art::Thread::Current()); |
| JvmtiGlobalTLSData* global_tls = ThreadUtil::GetGlobalTLSData(target); |
| if (global_tls != nullptr) { |
| global_tls->data.erase(env); |
| } |
| } |
| |
| void ThreadUtil::RemoveEnvironment(jvmtiEnv* env) { |
| art::Thread* self = art::Thread::Current(); |
| art::MutexLock mu(self, *art::Locks::thread_list_lock_); |
| art::ThreadList* list = art::Runtime::Current()->GetThreadList(); |
| list->ForEach(RemoveTLSData, env); |
| } |
| |
| jvmtiError ThreadUtil::SetThreadLocalStorage(jvmtiEnv* env, jthread thread, const void* data) { |
| art::Thread* self = art::Thread::Current(); |
| art::ScopedObjectAccess soa(self); |
| art::MutexLock mu(self, *art::Locks::thread_list_lock_); |
| art::Thread* target = nullptr; |
| jvmtiError err = ERR(INTERNAL); |
| if (!GetAliveNativeThread(thread, soa, &target, &err)) { |
| return err; |
| } |
| |
| JvmtiGlobalTLSData* global_tls = GetOrCreateGlobalTLSData(target); |
| |
| global_tls->data[env] = data; |
| |
| return ERR(NONE); |
| } |
| |
| JvmtiGlobalTLSData* ThreadUtil::GetOrCreateGlobalTLSData(art::Thread* thread) { |
| JvmtiGlobalTLSData* data = GetGlobalTLSData(thread); |
| if (data != nullptr) { |
| return data; |
| } else { |
| thread->SetCustomTLS(kJvmtiTlsKey, new JvmtiGlobalTLSData); |
| return GetGlobalTLSData(thread); |
| } |
| } |
| |
| JvmtiGlobalTLSData* ThreadUtil::GetGlobalTLSData(art::Thread* thread) { |
| return reinterpret_cast<JvmtiGlobalTLSData*>(thread->GetCustomTLS(kJvmtiTlsKey)); |
| } |
| |
| jvmtiError ThreadUtil::GetThreadLocalStorage(jvmtiEnv* env, |
| jthread thread, |
| void** data_ptr) { |
| if (data_ptr == nullptr) { |
| return ERR(NULL_POINTER); |
| } |
| |
| art::Thread* self = art::Thread::Current(); |
| art::ScopedObjectAccess soa(self); |
| art::MutexLock mu(self, *art::Locks::thread_list_lock_); |
| art::Thread* target = nullptr; |
| jvmtiError err = ERR(INTERNAL); |
| if (!GetAliveNativeThread(thread, soa, &target, &err)) { |
| return err; |
| } |
| |
| JvmtiGlobalTLSData* global_tls = GetGlobalTLSData(target); |
| if (global_tls == nullptr) { |
| *data_ptr = nullptr; |
| return OK; |
| } |
| auto it = global_tls->data.find(env); |
| if (it != global_tls->data.end()) { |
| *data_ptr = const_cast<void*>(it->second); |
| } else { |
| *data_ptr = nullptr; |
| } |
| |
| return ERR(NONE); |
| } |
| |
| struct AgentData { |
| const void* arg; |
| jvmtiStartFunction proc; |
| jthread thread; |
| JavaVM* java_vm; |
| jvmtiEnv* jvmti_env; |
| jint priority; |
| std::string name; |
| }; |
| |
| static void* AgentCallback(void* arg) { |
| std::unique_ptr<AgentData> data(reinterpret_cast<AgentData*>(arg)); |
| CHECK(data->thread != nullptr); |
| |
| // We already have a peer. So call our special Attach function. |
| art::Thread* self = art::Thread::Attach(data->name.c_str(), true, data->thread); |
| CHECK(self != nullptr) << "threads_being_born_ should have ensured thread could be attached."; |
| // The name in Attach() is only for logging. Set the thread name. This is important so |
| // that the thread is no longer seen as starting up. |
| { |
| art::ScopedObjectAccess soa(self); |
| self->SetThreadName(data->name.c_str()); |
| } |
| |
| // Release the peer. |
| JNIEnv* env = self->GetJniEnv(); |
| env->DeleteGlobalRef(data->thread); |
| data->thread = nullptr; |
| |
| { |
| // The StartThreadBirth was called in the parent thread. We let the runtime know we are up |
| // before going into the provided code. |
| art::MutexLock mu(art::Thread::Current(), *art::Locks::runtime_shutdown_lock_); |
| art::Runtime::Current()->EndThreadBirth(); |
| } |
| |
| // Run the agent code. |
| data->proc(data->jvmti_env, env, const_cast<void*>(data->arg)); |
| |
| // Detach the thread. |
| int detach_result = data->java_vm->DetachCurrentThread(); |
| CHECK_EQ(detach_result, 0); |
| |
| return nullptr; |
| } |
| |
| jvmtiError ThreadUtil::RunAgentThread(jvmtiEnv* jvmti_env, |
| jthread thread, |
| jvmtiStartFunction proc, |
| const void* arg, |
| jint priority) { |
| if (!PhaseUtil::IsLivePhase()) { |
| return ERR(WRONG_PHASE); |
| } |
| if (priority < JVMTI_THREAD_MIN_PRIORITY || priority > JVMTI_THREAD_MAX_PRIORITY) { |
| return ERR(INVALID_PRIORITY); |
| } |
| JNIEnv* env = art::Thread::Current()->GetJniEnv(); |
| if (thread == nullptr || !env->IsInstanceOf(thread, art::WellKnownClasses::java_lang_Thread)) { |
| return ERR(INVALID_THREAD); |
| } |
| if (proc == nullptr) { |
| return ERR(NULL_POINTER); |
| } |
| |
| { |
| art::Runtime* runtime = art::Runtime::Current(); |
| art::MutexLock mu(art::Thread::Current(), *art::Locks::runtime_shutdown_lock_); |
| if (runtime->IsShuttingDownLocked()) { |
| // The runtime is shutting down so we cannot create new threads. |
| // TODO It's not fully clear from the spec what we should do here. We aren't yet in |
| // JVMTI_PHASE_DEAD so we cannot return ERR(WRONG_PHASE) but creating new threads is now |
| // impossible. Existing agents don't seem to generally do anything with this return value so |
| // it doesn't matter too much. We could do something like sending a fake ThreadStart event |
| // even though code is never actually run. |
| return ERR(INTERNAL); |
| } |
| runtime->StartThreadBirth(); |
| } |
| |
| std::unique_ptr<AgentData> data(new AgentData); |
| data->arg = arg; |
| data->proc = proc; |
| // We need a global ref for Java objects, as local refs will be invalid. |
| data->thread = env->NewGlobalRef(thread); |
| data->java_vm = art::Runtime::Current()->GetJavaVM(); |
| data->jvmti_env = jvmti_env; |
| data->priority = priority; |
| ScopedLocalRef<jstring> s( |
| env, |
| reinterpret_cast<jstring>( |
| env->GetObjectField(thread, art::WellKnownClasses::java_lang_Thread_name))); |
| if (s == nullptr) { |
| data->name = "JVMTI Agent Thread"; |
| } else { |
| ScopedUtfChars name(env, s.get()); |
| data->name = name.c_str(); |
| } |
| |
| pthread_t pthread; |
| int pthread_create_result = pthread_create(&pthread, |
| nullptr, |
| &AgentCallback, |
| reinterpret_cast<void*>(data.get())); |
| if (pthread_create_result != 0) { |
| // If the create succeeded the other thread will call EndThreadBirth. |
| art::Runtime* runtime = art::Runtime::Current(); |
| art::MutexLock mu(art::Thread::Current(), *art::Locks::runtime_shutdown_lock_); |
| runtime->EndThreadBirth(); |
| return ERR(INTERNAL); |
| } |
| data.release(); // NOLINT pthreads API. |
| |
| return ERR(NONE); |
| } |
| |
| jvmtiError ThreadUtil::SuspendOther(art::Thread* self, |
| jthread target_jthread) { |
| // Loop since we need to bail out and try again if we would end up getting suspended while holding |
| // the user_code_suspension_lock_ due to a SuspendReason::kForUserCode. In this situation we |
| // release the lock, wait to get resumed and try again. |
| do { |
| // Suspend ourself if we have any outstanding suspends. This is so we won't suspend due to |
| // another SuspendThread in the middle of suspending something else potentially causing a |
| // deadlock. We need to do this in the loop because if we ended up back here then we had |
| // outstanding SuspendReason::kForUserCode suspensions and we should wait for them to be cleared |
| // before continuing. |
| SuspendCheck(self); |
| art::MutexLock mu(self, *art::Locks::user_code_suspension_lock_); |
| if (WouldSuspendForUserCodeLocked(self)) { |
| // Make sure we won't be suspended in the middle of holding the thread_suspend_count_lock_ by |
| // a user-code suspension. We retry and do another SuspendCheck to clear this. |
| continue; |
| } |
| // We are not going to be suspended by user code from now on. |
| { |
| art::ScopedObjectAccess soa(self); |
| art::MutexLock thread_list_mu(self, *art::Locks::thread_list_lock_); |
| art::Thread* target = nullptr; |
| jvmtiError err = ERR(INTERNAL); |
| if (!GetAliveNativeThread(target_jthread, soa, &target, &err)) { |
| return err; |
| } |
| art::ThreadState state = target->GetState(); |
| if (state == art::ThreadState::kStarting || target->IsStillStarting()) { |
| return ERR(THREAD_NOT_ALIVE); |
| } else { |
| art::MutexLock thread_suspend_count_mu(self, *art::Locks::thread_suspend_count_lock_); |
| if (target->GetUserCodeSuspendCount() != 0) { |
| return ERR(THREAD_SUSPENDED); |
| } |
| } |
| } |
| bool timeout = true; |
| art::Thread* ret_target = art::Runtime::Current()->GetThreadList()->SuspendThreadByPeer( |
| target_jthread, |
| /* request_suspension= */ true, |
| art::SuspendReason::kForUserCode, |
| &timeout); |
| if (ret_target == nullptr && !timeout) { |
| // TODO It would be good to get more information about why exactly the thread failed to |
| // suspend. |
| return ERR(INTERNAL); |
| } else if (!timeout) { |
| // we didn't time out and got a result. |
| return OK; |
| } |
| // We timed out. Just go around and try again. |
| } while (true); |
| UNREACHABLE(); |
| } |
| |
| jvmtiError ThreadUtil::SuspendSelf(art::Thread* self) { |
| CHECK(self == art::Thread::Current()); |
| { |
| art::MutexLock mu(self, *art::Locks::user_code_suspension_lock_); |
| art::MutexLock thread_list_mu(self, *art::Locks::thread_suspend_count_lock_); |
| if (self->GetUserCodeSuspendCount() != 0) { |
| // This can only happen if we race with another thread to suspend 'self' and we lose. |
| return ERR(THREAD_SUSPENDED); |
| } |
| // We shouldn't be able to fail this. |
| if (!self->ModifySuspendCount(self, +1, nullptr, art::SuspendReason::kForUserCode)) { |
| // TODO More specific error would be nice. |
| return ERR(INTERNAL); |
| } |
| } |
| // Once we have requested the suspend we actually go to sleep. We need to do this after releasing |
| // the suspend_lock to make sure we can be woken up. This call gains the mutator lock causing us |
| // to go to sleep until we are resumed. |
| SuspendCheck(self); |
| return OK; |
| } |
| |
| jvmtiError ThreadUtil::SuspendThread(jvmtiEnv* env ATTRIBUTE_UNUSED, jthread thread) { |
| art::Thread* self = art::Thread::Current(); |
| bool target_is_self = false; |
| { |
| art::ScopedObjectAccess soa(self); |
| art::MutexLock mu(self, *art::Locks::thread_list_lock_); |
| art::Thread* target = nullptr; |
| jvmtiError err = ERR(INTERNAL); |
| if (!GetAliveNativeThread(thread, soa, &target, &err)) { |
| return err; |
| } else if (target == self) { |
| target_is_self = true; |
| } |
| } |
| if (target_is_self) { |
| return SuspendSelf(self); |
| } else { |
| return SuspendOther(self, thread); |
| } |
| } |
| |
| jvmtiError ThreadUtil::ResumeThread(jvmtiEnv* env ATTRIBUTE_UNUSED, |
| jthread thread) { |
| if (thread == nullptr) { |
| return ERR(NULL_POINTER); |
| } |
| art::Thread* self = art::Thread::Current(); |
| art::Thread* target; |
| // Retry until we know we won't get suspended by user code while resuming something. |
| do { |
| SuspendCheck(self); |
| art::MutexLock ucsl_mu(self, *art::Locks::user_code_suspension_lock_); |
| if (WouldSuspendForUserCodeLocked(self)) { |
| // Make sure we won't be suspended in the middle of holding the thread_suspend_count_lock_ by |
| // a user-code suspension. We retry and do another SuspendCheck to clear this. |
| continue; |
| } |
| // From now on we know we cannot get suspended by user-code. |
| { |
| // NB This does a SuspendCheck (during thread state change) so we need to make sure we don't |
| // have the 'suspend_lock' locked here. |
| art::ScopedObjectAccess soa(self); |
| art::MutexLock tll_mu(self, *art::Locks::thread_list_lock_); |
| jvmtiError err = ERR(INTERNAL); |
| if (!GetAliveNativeThread(thread, soa, &target, &err)) { |
| return err; |
| } else if (target == self) { |
| // We would have paused until we aren't suspended anymore due to the ScopedObjectAccess so |
| // we can just return THREAD_NOT_SUSPENDED. Unfortunately we cannot do any real DCHECKs |
| // about current state since it's all concurrent. |
| return ERR(THREAD_NOT_SUSPENDED); |
| } |
| // The JVMTI spec requires us to return THREAD_NOT_SUSPENDED if it is alive but we really |
| // cannot tell why resume failed. |
| { |
| art::MutexLock thread_suspend_count_mu(self, *art::Locks::thread_suspend_count_lock_); |
| if (target->GetUserCodeSuspendCount() == 0) { |
| return ERR(THREAD_NOT_SUSPENDED); |
| } |
| } |
| } |
| // It is okay that we don't have a thread_list_lock here since we know that the thread cannot |
| // die since it is currently held suspended by a SuspendReason::kForUserCode suspend. |
| DCHECK(target != self); |
| if (!art::Runtime::Current()->GetThreadList()->Resume(target, |
| art::SuspendReason::kForUserCode)) { |
| // TODO Give a better error. |
| // This is most likely THREAD_NOT_SUSPENDED but we cannot really be sure. |
| return ERR(INTERNAL); |
| } else { |
| return OK; |
| } |
| } while (true); |
| } |
| |
| static bool IsCurrentThread(jthread thr) { |
| if (thr == nullptr) { |
| return true; |
| } |
| art::Thread* self = art::Thread::Current(); |
| art::ScopedObjectAccess soa(self); |
| art::MutexLock mu(self, *art::Locks::thread_list_lock_); |
| art::Thread* target = nullptr; |
| jvmtiError err_unused = ERR(INTERNAL); |
| if (ThreadUtil::GetNativeThread(thr, soa, &target, &err_unused)) { |
| return target == self; |
| } else { |
| return false; |
| } |
| } |
| |
| // Suspends all the threads in the list at the same time. Getting this behavior is a little tricky |
| // since we can have threads in the list multiple times. This generally doesn't matter unless the |
| // current thread is present multiple times. In that case we need to suspend only once and either |
| // return the same error code in all the other slots if it failed or return ERR(THREAD_SUSPENDED) if |
| // it didn't. We also want to handle the current thread last to make the behavior of the code |
| // simpler to understand. |
| jvmtiError ThreadUtil::SuspendThreadList(jvmtiEnv* env, |
| jint request_count, |
| const jthread* threads, |
| jvmtiError* results) { |
| if (request_count == 0) { |
| return ERR(ILLEGAL_ARGUMENT); |
| } else if (results == nullptr || threads == nullptr) { |
| return ERR(NULL_POINTER); |
| } |
| // This is the list of the indexes in 'threads' and 'results' that correspond to the currently |
| // running thread. These indexes we need to handle specially since we need to only actually |
| // suspend a single time. |
| std::vector<jint> current_thread_indexes; |
| for (jint i = 0; i < request_count; i++) { |
| if (IsCurrentThread(threads[i])) { |
| current_thread_indexes.push_back(i); |
| } else { |
| results[i] = env->SuspendThread(threads[i]); |
| } |
| } |
| if (!current_thread_indexes.empty()) { |
| jint first_current_thread_index = current_thread_indexes[0]; |
| // Suspend self. |
| jvmtiError res = env->SuspendThread(threads[first_current_thread_index]); |
| results[first_current_thread_index] = res; |
| // Fill in the rest of the error values as appropriate. |
| jvmtiError other_results = (res != OK) ? res : ERR(THREAD_SUSPENDED); |
| for (auto it = ++current_thread_indexes.begin(); it != current_thread_indexes.end(); ++it) { |
| results[*it] = other_results; |
| } |
| } |
| return OK; |
| } |
| |
| jvmtiError ThreadUtil::ResumeThreadList(jvmtiEnv* env, |
| jint request_count, |
| const jthread* threads, |
| jvmtiError* results) { |
| if (request_count == 0) { |
| return ERR(ILLEGAL_ARGUMENT); |
| } else if (results == nullptr || threads == nullptr) { |
| return ERR(NULL_POINTER); |
| } |
| for (jint i = 0; i < request_count; i++) { |
| results[i] = env->ResumeThread(threads[i]); |
| } |
| return OK; |
| } |
| |
| jvmtiError ThreadUtil::StopThread(jvmtiEnv* env ATTRIBUTE_UNUSED, |
| jthread thread, |
| jobject exception) { |
| art::Thread* self = art::Thread::Current(); |
| art::ScopedObjectAccess soa(self); |
| art::StackHandleScope<1> hs(self); |
| if (exception == nullptr) { |
| return ERR(INVALID_OBJECT); |
| } |
| art::ObjPtr<art::mirror::Object> obj(soa.Decode<art::mirror::Object>(exception)); |
| if (!obj->GetClass()->IsThrowableClass()) { |
| return ERR(INVALID_OBJECT); |
| } |
| art::Handle<art::mirror::Throwable> exc(hs.NewHandle(obj->AsThrowable())); |
| art::Locks::thread_list_lock_->ExclusiveLock(self); |
| art::Thread* target = nullptr; |
| jvmtiError err = ERR(INTERNAL); |
| if (!GetAliveNativeThread(thread, soa, &target, &err)) { |
| art::Locks::thread_list_lock_->ExclusiveUnlock(self); |
| return err; |
| } else if (target->GetState() == art::ThreadState::kStarting || target->IsStillStarting()) { |
| art::Locks::thread_list_lock_->ExclusiveUnlock(self); |
| return ERR(THREAD_NOT_ALIVE); |
| } |
| struct StopThreadClosure : public art::Closure { |
| public: |
| explicit StopThreadClosure(art::Handle<art::mirror::Throwable> except) : exception_(except) { } |
| |
| void Run(art::Thread* me) override REQUIRES_SHARED(art::Locks::mutator_lock_) { |
| // Make sure the thread is prepared to notice the exception. |
| art::Runtime::Current()->GetInstrumentation()->InstrumentThreadStack(me); |
| me->SetAsyncException(exception_.Get()); |
| // Wake up the thread if it is sleeping. |
| me->Notify(); |
| } |
| |
| private: |
| art::Handle<art::mirror::Throwable> exception_; |
| }; |
| StopThreadClosure c(exc); |
| // RequestSynchronousCheckpoint releases the thread_list_lock_ as a part of its execution. |
| if (target->RequestSynchronousCheckpoint(&c)) { |
| return OK; |
| } else { |
| // Something went wrong, probably the thread died. |
| return ERR(THREAD_NOT_ALIVE); |
| } |
| } |
| |
| jvmtiError ThreadUtil::InterruptThread(jvmtiEnv* env ATTRIBUTE_UNUSED, jthread thread) { |
| art::Thread* self = art::Thread::Current(); |
| art::ScopedObjectAccess soa(self); |
| art::MutexLock tll_mu(self, *art::Locks::thread_list_lock_); |
| art::Thread* target = nullptr; |
| jvmtiError err = ERR(INTERNAL); |
| if (!GetAliveNativeThread(thread, soa, &target, &err)) { |
| return err; |
| } else if (target->GetState() == art::ThreadState::kStarting || target->IsStillStarting()) { |
| return ERR(THREAD_NOT_ALIVE); |
| } |
| target->Interrupt(self); |
| return OK; |
| } |
| |
| } // namespace openjdkjvmti |