/* 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. */ #ifndef ART_OPENJDKJVMTI_TI_THREAD_H_ #define ART_OPENJDKJVMTI_TI_THREAD_H_ #include #include "jni.h" #include "jvmti.h" #include "base/macros.h" #include "base/mutex.h" #include "thread.h" namespace art { class ArtField; class ScopedObjectAccessAlreadyRunnable; class Thread; class Closure; } // namespace art namespace openjdkjvmti { class EventHandler; // Gains the user_code_suspension_lock_ and ensures that the code will not suspend for user-code. class SCOPED_CAPABILITY ScopedNoUserCodeSuspension { public: explicit ScopedNoUserCodeSuspension(art::Thread* self) ACQUIRE(art::Locks::user_code_suspension_lock_); ~ScopedNoUserCodeSuspension() RELEASE(art::Locks::user_code_suspension_lock_); private: art::Thread* self_; }; // The struct that we store in the art::Thread::custom_tls_ that maps the jvmtiEnvs to the data // stored with that thread. This is needed since different jvmtiEnvs are not supposed to share TLS // data but we only have a single slot in Thread objects to store data. struct JvmtiGlobalTLSData : public art::TLSData { std::unordered_map data GUARDED_BY(art::Locks::thread_list_lock_); // The depth of the last frame where popping using PopFrame it is not allowed. It is set to // kNoDisallowedPopFrame if all frames can be popped. See b/117615146 for more information. static constexpr size_t kNoDisallowedPopFrame = -1; size_t disable_pop_frame_depth = kNoDisallowedPopFrame; }; class ThreadUtil { public: static void Register(EventHandler* event_handler); static void Unregister(); // To be called when it is safe to cache data. This means that we have at least entered the // RuntimePhase::kInit but we might or might not have already called VMInit event. static void CacheData(); // Called just after we have sent the VMInit callback so that ThreadUtil can do final setup. This // ensures that there are no timing issues between the two callbacks. static void VMInitEventSent() REQUIRES_SHARED(art::Locks::mutator_lock_); // Handle a jvmtiEnv going away. static void RemoveEnvironment(jvmtiEnv* env); static jvmtiError GetAllThreads(jvmtiEnv* env, jint* threads_count_ptr, jthread** threads_ptr); static jvmtiError GetCurrentThread(jvmtiEnv* env, jthread* thread_ptr); static jvmtiError GetThreadInfo(jvmtiEnv* env, jthread thread, jvmtiThreadInfo* info_ptr); static jvmtiError GetThreadState(jvmtiEnv* env, jthread thread, jint* thread_state_ptr); static jvmtiError SetThreadLocalStorage(jvmtiEnv* env, jthread thread, const void* data); static jvmtiError GetThreadLocalStorage(jvmtiEnv* env, jthread thread, void** data_ptr); static jvmtiError RunAgentThread(jvmtiEnv* env, jthread thread, jvmtiStartFunction proc, const void* arg, jint priority); static jvmtiError SuspendThread(jvmtiEnv* env, jthread thread); static jvmtiError ResumeThread(jvmtiEnv* env, jthread thread); static jvmtiError SuspendThreadList(jvmtiEnv* env, jint request_count, const jthread* threads, jvmtiError* results); static jvmtiError ResumeThreadList(jvmtiEnv* env, jint request_count, const jthread* threads, jvmtiError* results); static jvmtiError StopThread(jvmtiEnv* env, jthread thr, jobject exception); static jvmtiError InterruptThread(jvmtiEnv* env, jthread thr); // Returns true if we decoded the thread and it is alive, false otherwise with an appropriate // error placed into 'err'. A thread is alive if it has had it's 'start' function called and has // (or at least could have) executed managed code and has not yet returned past it's first managed // frame. This means that the thread returned might have IsStillStarting() return true. Code that // does not consider that alive should check manually. static bool GetAliveNativeThread(jthread thread, const art::ScopedObjectAccessAlreadyRunnable& soa, /*out*/ art::Thread** thr, /*out*/ jvmtiError* err) REQUIRES_SHARED(art::Locks::mutator_lock_) REQUIRES(art::Locks::thread_list_lock_); // Returns true if we decoded the thread, false otherwise with an appropriate error placed into // 'err' static bool GetNativeThread(jthread thread, const art::ScopedObjectAccessAlreadyRunnable& soa, /*out*/ art::Thread** thr, /*out*/ jvmtiError* err) REQUIRES_SHARED(art::Locks::mutator_lock_) REQUIRES(art::Locks::thread_list_lock_); // Go to sleep if this thread is suspended. static void SuspendCheck(art::Thread* self) REQUIRES(!art::Locks::mutator_lock_, !art::Locks::user_code_suspension_lock_); // Returns true if the thread would be suspended if it locks the mutator-lock or calls // SuspendCheck. This function is called with the user_code_suspension_lock already held. static bool WouldSuspendForUserCodeLocked(art::Thread* self) REQUIRES(art::Locks::user_code_suspension_lock_, !art::Locks::thread_suspend_count_lock_); // Returns true if this thread would go to sleep if it locks the mutator-lock or calls // SuspendCheck. static bool WouldSuspendForUserCode(art::Thread* self) REQUIRES(!art::Locks::user_code_suspension_lock_, !art::Locks::thread_suspend_count_lock_); static JvmtiGlobalTLSData* GetGlobalTLSData(art::Thread* thread) REQUIRES(art::Locks::thread_list_lock_); static JvmtiGlobalTLSData* GetOrCreateGlobalTLSData(art::Thread* thread) REQUIRES(art::Locks::thread_list_lock_); private: // We need to make sure only one thread tries to suspend threads at a time so we can get the // 'suspend-only-once' behavior the spec requires. Internally, ART considers suspension to be a // counted state, allowing a single thread to be suspended multiple times by different users. This // makes mapping into the JVMTI idea of thread suspension difficult. We have decided to split the // difference and ensure that JVMTI tries to treat suspension as the boolean flag as much as // possible with the suspend/resume methods but only do best effort. On the other hand // GetThreadState will be totally accurate as much as possible. This means that calling // ResumeThread on a thread that has state JVMTI_THREAD_STATE_SUSPENDED will not necessarily // cause the thread to wake up if the thread is suspended for the debugger or gc or something. static jvmtiError SuspendSelf(art::Thread* self) REQUIRES(!art::Locks::mutator_lock_, !art::Locks::user_code_suspension_lock_); static jvmtiError SuspendOther(art::Thread* self, jthread target_jthread) REQUIRES(!art::Locks::mutator_lock_, !art::Locks::user_code_suspension_lock_); static art::ArtField* context_class_loader_; }; } // namespace openjdkjvmti #endif // ART_OPENJDKJVMTI_TI_THREAD_H_