/* 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 <unordered_map>
#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<jvmtiEnv*, const void*> 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_