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/* 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/strings.h"
#include "art_field.h"
#include "art_jvmti.h"
#include "base/logging.h"
#include "base/mutex.h"
#include "events-inl.h"
#include "gc/system_weak.h"
#include "gc_root-inl.h"
#include "jni_internal.h"
#include "mirror/class.h"
#include "mirror/object-inl.h"
#include "mirror/string.h"
#include "obj_ptr.h"
#include "runtime.h"
#include "runtime_callbacks.h"
#include "ScopedLocalRef.h"
#include "scoped_thread_state_change-inl.h"
#include "thread-inl.h"
#include "thread_list.h"
#include "well_known_classes.h"
namespace openjdkjvmti {
struct ThreadCallback : public art::ThreadLifecycleCallback, public art::RuntimePhaseCallback {
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;
}
}
return;
}
Post<ArtJvmtiEvent::kThreadStart>(self);
}
void ThreadDeath(art::Thread* self) OVERRIDE REQUIRES_SHARED(art::Locks::mutator_lock_) {
Post<ArtJvmtiEvent::kThreadEnd>(self);
}
void NextRuntimePhase(RuntimePhase phase) OVERRIDE REQUIRES_SHARED(art::Locks::mutator_lock_) {
if (phase == RuntimePhase::kInit) {
// We moved to VMInit. Report the main thread as started (it was attached early, and must
// not be reported until Init.
started = true;
Post<ArtJvmtiEvent::kThreadStart>(art::Thread::Current());
}
}
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);
runtime->GetRuntimeCallbacks()->AddRuntimePhaseCallback(&gThreadCallback);
}
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);
runtime->GetRuntimeCallbacks()->RemoveRuntimePhaseCallback(&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);
}
// Read the context classloader from a Java thread object. This is a lazy implementation
// that assumes GetThreadInfo isn't called too often. If we instead cache the ArtField,
// we will have to add synchronization as this can't be cached on startup (which is
// potentially runtime startup).
static art::ObjPtr<art::mirror::Object> GetContextClassLoader(art::ObjPtr<art::mirror::Object> peer)
REQUIRES_SHARED(art::Locks::mutator_lock_) {
if (peer == nullptr) {
return nullptr;
}
art::ObjPtr<art::mirror::Class> klass = peer->GetClass();
art::ArtField* cc_field = klass->FindDeclaredInstanceField("contextClassLoader",
"Ljava/lang/ClassLoader;");
CHECK(cc_field != nullptr);
return cc_field->GetObject(peer);
}
// Get the native thread. The spec says a null object denotes the current thread.
static art::Thread* GetNativeThread(jthread thread,
const art::ScopedObjectAccessAlreadyRunnable& soa)
REQUIRES_SHARED(art::Locks::mutator_lock_) {
if (thread == nullptr) {
return art::Thread::Current();
}
art::MutexLock mu(soa.Self(), *art::Locks::thread_list_lock_);
return art::Thread::FromManagedThread(soa, thread);
}
jvmtiError ThreadUtil::GetThreadInfo(jvmtiEnv* env, jthread thread, jvmtiThreadInfo* info_ptr) {
if (info_ptr == nullptr) {
return ERR(NULL_POINTER);
}
art::ScopedObjectAccess soa(art::Thread::Current());
art::Thread* self = GetNativeThread(thread, soa);
if (self == nullptr && thread == nullptr) {
return ERR(INVALID_THREAD);
}
JvmtiUniquePtr<char[]> name_uptr;
if (self != nullptr) {
// Have a native thread object, this thread is alive.
std::string name;
self->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 = self->GetNativePriority();
info_ptr->is_daemon = self->IsDaemon();
art::ObjPtr<art::mirror::Object> peer = self->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.
art::ObjPtr<art::mirror::Object> ccl = GetContextClassLoader(peer);
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.
art::ObjPtr<art::mirror::Object> ccl = GetContextClassLoader(peer);
info_ptr->context_class_loader = ccl == nullptr
? nullptr
: soa.AddLocalReference<jobject>(ccl);
}
name_uptr.release();
return ERR(NONE);
}
// Return the thread's (or current thread, if null) thread state. Return kStarting in case
// there's no native counterpart (thread hasn't been started, yet, or is dead).
static art::ThreadState GetNativeThreadState(jthread thread,
const art::ScopedObjectAccessAlreadyRunnable& soa,
art::Thread** native_thread)
REQUIRES_SHARED(art::Locks::mutator_lock_) {
art::Thread* self = nullptr;
art::MutexLock mu(soa.Self(), *art::Locks::thread_list_lock_);
if (thread == nullptr) {
self = art::Thread::Current();
} else {
self = art::Thread::FromManagedThread(soa, thread);
}
*native_thread = self;
if (self == nullptr || self->IsStillStarting()) {
return art::ThreadState::kStarting;
}
return self->GetState();
}
static jint GetJvmtiThreadStateFromInternal(art::ThreadState internal_thread_state) {
jint jvmti_state = JVMTI_THREAD_STATE_ALIVE;
if (internal_thread_state == art::ThreadState::kSuspended) {
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 (internal_thread_state == art::ThreadState::kNative) {
jvmti_state |= JVMTI_THREAD_STATE_IN_NATIVE;
}
if (internal_thread_state == art::ThreadState::kRunnable ||
internal_thread_state == art::ThreadState::kWaitingWeakGcRootRead ||
internal_thread_state == art::ThreadState::kSuspended) {
jvmti_state |= JVMTI_THREAD_STATE_RUNNABLE;
} else if (internal_thread_state == art::ThreadState::kBlocked) {
jvmti_state |= JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER;
} else {
// Should be in waiting state.
jvmti_state |= JVMTI_THREAD_STATE_WAITING;
if (internal_thread_state == art::ThreadState::kTimedWaiting ||
internal_thread_state == art::ThreadState::kSleeping) {
jvmti_state |= JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT;
} else {
jvmti_state |= JVMTI_THREAD_STATE_WAITING_INDEFINITELY;
}
if (internal_thread_state == art::ThreadState::kSleeping) {
jvmti_state |= JVMTI_THREAD_STATE_SLEEPING;
}
if (internal_thread_state == art::ThreadState::kTimedWaiting ||
internal_thread_state == art::ThreadState::kWaiting) {
jvmti_state |= JVMTI_THREAD_STATE_IN_OBJECT_WAIT;
}
// TODO: PARKED. We'll have to inspect the stack.
}
return jvmti_state;
}
static jint GetJavaStateFromInternal(art::ThreadState internal_thread_state) {
switch (internal_thread_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::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();
}
jvmtiError ThreadUtil::GetThreadState(jvmtiEnv* env ATTRIBUTE_UNUSED,
jthread thread,
jint* thread_state_ptr) {
if (thread_state_ptr == nullptr) {
return ERR(NULL_POINTER);
}
art::ScopedObjectAccess soa(art::Thread::Current());
art::Thread* native_thread = nullptr;
art::ThreadState internal_thread_state = GetNativeThreadState(thread, soa, &native_thread);
if (internal_thread_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);
}
// Need to read the Java "started" field to know whether this is starting or terminated.
art::ObjPtr<art::mirror::Object> peer = soa.Decode<art::mirror::Object>(thread);
art::ObjPtr<art::mirror::Class> klass = peer->GetClass();
art::ArtField* started_field = klass->FindDeclaredInstanceField("started", "Z");
CHECK(started_field != nullptr);
bool started = started_field->GetBoolean(peer) != 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);
}
DCHECK(native_thread != nullptr);
// Translate internal thread state to JVMTI and Java state.
jint jvmti_state = GetJvmtiThreadStateFromInternal(internal_thread_state);
if (native_thread->IsInterrupted()) {
jvmti_state |= JVMTI_THREAD_STATE_INTERRUPTED;
}
// Java state is derived from nativeGetState.
// Note: Our implementation assigns "runnable" to suspended. As such, we will have slightly
// different mask. However, this is for consistency with the Java view.
jint java_state = GetJavaStateFromInternal(internal_thread_state);
*thread_state_ptr = jvmti_state | java_state;
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);
}
jvmtiError ThreadUtil::SetThreadLocalStorage(jvmtiEnv* env ATTRIBUTE_UNUSED,
jthread thread,
const void* data) {
art::ScopedObjectAccess soa(art::Thread::Current());
art::Thread* self = GetNativeThread(thread, soa);
if (self == nullptr && thread == nullptr) {
return ERR(INVALID_THREAD);
}
if (self == nullptr) {
return ERR(THREAD_NOT_ALIVE);
}
self->SetCustomTLS(data);
return ERR(NONE);
}
jvmtiError ThreadUtil::GetThreadLocalStorage(jvmtiEnv* env ATTRIBUTE_UNUSED,
jthread thread,
void** data_ptr) {
if (data_ptr == nullptr) {
return ERR(NULL_POINTER);
}
art::ScopedObjectAccess soa(art::Thread::Current());
art::Thread* self = GetNativeThread(thread, soa);
if (self == nullptr && thread == nullptr) {
return ERR(INVALID_THREAD);
}
if (self == nullptr) {
return ERR(THREAD_NOT_ALIVE);
}
*data_ptr = const_cast<void*>(self->GetCustomTLS());
return ERR(NONE);
}
struct AgentData {
const void* arg;
jvmtiStartFunction proc;
jthread thread;
JavaVM* java_vm;
jvmtiEnv* jvmti_env;
jint priority;
};
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("JVMTI Agent thread", true, data->thread);
CHECK(self != nullptr);
// 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("JVMTI Agent thread");
}
// Release the peer.
JNIEnv* env = self->GetJniEnv();
env->DeleteGlobalRef(data->thread);
data->thread = nullptr;
// 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 (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);
}
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;
pthread_t pthread;
int pthread_create_result = pthread_create(&pthread,
nullptr,
&AgentCallback,
reinterpret_cast<void*>(data.get()));
if (pthread_create_result != 0) {
return ERR(INTERNAL);
}
data.release();
return ERR(NONE);
}
} // namespace openjdkjvmti