/* * Copyright (c) 2003, 2025, 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. * * 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 "classfile/classLoaderDataGraph.hpp" #include "classfile/javaClasses.inline.hpp" #include "classfile/moduleEntry.hpp" #include "classfile/symbolTable.hpp" #include "classfile/vmSymbols.hpp" #include "jvmtifiles/jvmtiEnv.hpp" #include "memory/iterator.hpp" #include "memory/resourceArea.hpp" #include "oops/klass.inline.hpp" #include "oops/objArrayKlass.hpp" #include "oops/objArrayOop.hpp" #include "oops/oop.inline.hpp" #include "oops/oopHandle.inline.hpp" #include "prims/jvmtiEnvBase.hpp" #include "prims/jvmtiEventController.inline.hpp" #include "prims/jvmtiExtensions.hpp" #include "prims/jvmtiImpl.hpp" #include "prims/jvmtiManageCapabilities.hpp" #include "prims/jvmtiTagMap.hpp" #include "prims/jvmtiThreadState.inline.hpp" #include "runtime/continuationEntry.inline.hpp" #include "runtime/deoptimization.hpp" #include "runtime/frame.inline.hpp" #include "runtime/handles.inline.hpp" #include "runtime/interfaceSupport.inline.hpp" #include "runtime/javaCalls.hpp" #include "runtime/javaThread.inline.hpp" #include "runtime/jfieldIDWorkaround.hpp" #include "runtime/jniHandles.inline.hpp" #include "runtime/objectMonitor.inline.hpp" #include "runtime/osThread.hpp" #include "runtime/signature.hpp" #include "runtime/stackWatermarkSet.inline.hpp" #include "runtime/synchronizer.inline.hpp" #include "runtime/threads.hpp" #include "runtime/threadSMR.inline.hpp" #include "runtime/vframe.inline.hpp" #include "runtime/vframe_hp.hpp" #include "runtime/vmThread.hpp" #include "runtime/vmOperations.hpp" #include "services/threadService.hpp" /////////////////////////////////////////////////////////////// // // JvmtiEnvBase // JvmtiEnvBase* JvmtiEnvBase::_head_environment = nullptr; bool JvmtiEnvBase::_globally_initialized = false; volatile bool JvmtiEnvBase::_needs_clean_up = false; jvmtiPhase JvmtiEnvBase::_phase = JVMTI_PHASE_PRIMORDIAL; volatile int JvmtiEnvBase::_dying_thread_env_iteration_count = 0; extern jvmtiInterface_1_ jvmti_Interface; extern jvmtiInterface_1_ jvmtiTrace_Interface; // perform initializations that must occur before any JVMTI environments // are released but which should only be initialized once (no matter // how many environments are created). void JvmtiEnvBase::globally_initialize() { assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(), "sanity check"); assert(_globally_initialized == false, "bad call"); JvmtiManageCapabilities::initialize(); // register extension functions and events JvmtiExtensions::register_extensions(); #ifdef JVMTI_TRACE JvmtiTrace::initialize(); #endif _globally_initialized = true; } void JvmtiEnvBase::initialize() { assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(), "sanity check"); // Add this environment to the end of the environment list (order is important) { // This block of code must not contain any safepoints, as list deallocation // (which occurs at a safepoint) cannot occur simultaneously with this list // addition. Note: NoSafepointVerifier cannot, currently, be used before // threads exist. JvmtiEnvIterator it; JvmtiEnvBase *previous_env = nullptr; for (JvmtiEnvBase* env = it.first(); env != nullptr; env = it.next(env)) { previous_env = env; } if (previous_env == nullptr) { _head_environment = this; } else { previous_env->set_next_environment(this); } } if (_globally_initialized == false) { globally_initialize(); } } jvmtiPhase JvmtiEnvBase::phase() { // For the JVMTI environments possessed the can_generate_early_vmstart: // replace JVMTI_PHASE_PRIMORDIAL with JVMTI_PHASE_START if (_phase == JVMTI_PHASE_PRIMORDIAL && JvmtiExport::early_vmstart_recorded() && early_vmstart_env()) { return JVMTI_PHASE_START; } return _phase; // Normal case } bool JvmtiEnvBase::is_valid() { jlong value = 0; // This object might not be a JvmtiEnvBase so we can't assume // the _magic field is properly aligned. Get the value in a safe // way and then check against JVMTI_MAGIC. switch (sizeof(_magic)) { case 2: value = Bytes::get_native_u2((address)&_magic); break; case 4: value = Bytes::get_native_u4((address)&_magic); break; case 8: value = Bytes::get_native_u8((address)&_magic); break; default: guarantee(false, "_magic field is an unexpected size"); } return value == JVMTI_MAGIC; } bool JvmtiEnvBase::use_version_1_0_semantics() { int major, minor, micro; JvmtiExport::decode_version_values(_version, &major, &minor, µ); return major == 1 && minor == 0; // micro version doesn't matter here } bool JvmtiEnvBase::use_version_1_1_semantics() { int major, minor, micro; JvmtiExport::decode_version_values(_version, &major, &minor, µ); return major == 1 && minor == 1; // micro version doesn't matter here } bool JvmtiEnvBase::use_version_1_2_semantics() { int major, minor, micro; JvmtiExport::decode_version_values(_version, &major, &minor, µ); return major == 1 && minor == 2; // micro version doesn't matter here } JvmtiEnvBase::JvmtiEnvBase(jint version) : _env_event_enable() { _version = version; _env_local_storage = nullptr; _tag_map = nullptr; _native_method_prefix_count = 0; _native_method_prefixes = nullptr; _next = nullptr; _class_file_load_hook_ever_enabled = false; // Moot since ClassFileLoadHook not yet enabled. // But "true" will give a more predictable ClassFileLoadHook behavior // for environment creation during ClassFileLoadHook. _is_retransformable = true; // all callbacks initially null memset(&_event_callbacks, 0, sizeof(jvmtiEventCallbacks)); memset(&_ext_event_callbacks, 0, sizeof(jvmtiExtEventCallbacks)); // all capabilities initially off memset(&_current_capabilities, 0, sizeof(_current_capabilities)); // all prohibited capabilities initially off memset(&_prohibited_capabilities, 0, sizeof(_prohibited_capabilities)); _magic = JVMTI_MAGIC; JvmtiEventController::env_initialize((JvmtiEnv*)this); #ifdef JVMTI_TRACE _jvmti_external.functions = TraceJVMTI != nullptr ? &jvmtiTrace_Interface : &jvmti_Interface; #else _jvmti_external.functions = &jvmti_Interface; #endif } void JvmtiEnvBase::dispose() { #ifdef JVMTI_TRACE JvmtiTrace::shutdown(); #endif // Dispose of event info and let the event controller call us back // in a locked state (env_dispose, below) JvmtiEventController::env_dispose(this); } void JvmtiEnvBase::env_dispose() { assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(), "sanity check"); // We have been entered with all events disabled on this environment. // A race to re-enable events (by setting callbacks) is prevented by // checking for a valid environment when setting callbacks (while // holding the JvmtiThreadState_lock). // Mark as invalid. _magic = DISPOSED_MAGIC; // Relinquish all capabilities. jvmtiCapabilities *caps = get_capabilities(); JvmtiManageCapabilities::relinquish_capabilities(caps, caps, caps); // Same situation as with events (see above) set_native_method_prefixes(0, nullptr); JvmtiTagMap* tag_map_to_clear = tag_map_acquire(); // A tag map can be big, clear it now to save memory until // the destructor runs. if (tag_map_to_clear != nullptr) { tag_map_to_clear->clear(); } _needs_clean_up = true; } JvmtiEnvBase::~JvmtiEnvBase() { assert(SafepointSynchronize::is_at_safepoint(), "sanity check"); // There is a small window of time during which the tag map of a // disposed environment could have been reallocated. // Make sure it is gone. JvmtiTagMap* tag_map_to_deallocate = _tag_map; set_tag_map(nullptr); // A tag map can be big, deallocate it now if (tag_map_to_deallocate != nullptr) { delete tag_map_to_deallocate; } _magic = BAD_MAGIC; } void JvmtiEnvBase::periodic_clean_up() { assert(SafepointSynchronize::is_at_safepoint(), "sanity check"); // JvmtiEnvBase reference is saved in JvmtiEnvThreadState. So // clean up JvmtiThreadState before deleting JvmtiEnv pointer. JvmtiThreadState::periodic_clean_up(); // Unlink all invalid environments from the list of environments // and deallocate them JvmtiEnvIterator it; JvmtiEnvBase* previous_env = nullptr; JvmtiEnvBase* env = it.first(); while (env != nullptr) { if (env->is_valid()) { previous_env = env; env = it.next(env); } else { // This one isn't valid, remove it from the list and deallocate it JvmtiEnvBase* defunct_env = env; env = it.next(env); if (previous_env == nullptr) { _head_environment = env; } else { previous_env->set_next_environment(env); } delete defunct_env; } } } void JvmtiEnvBase::check_for_periodic_clean_up() { assert(SafepointSynchronize::is_at_safepoint(), "sanity check"); class ThreadInsideIterationClosure: public ThreadClosure { private: bool _inside; public: ThreadInsideIterationClosure() : _inside(false) {}; void do_thread(Thread* thread) { _inside |= thread->is_inside_jvmti_env_iteration(); } bool is_inside_jvmti_env_iteration() { return _inside; } }; if (_needs_clean_up) { // Check if we are currently iterating environment, // deallocation should not occur if we are ThreadInsideIterationClosure tiic; Threads::threads_do(&tiic); if (!tiic.is_inside_jvmti_env_iteration() && !is_inside_dying_thread_env_iteration()) { _needs_clean_up = false; JvmtiEnvBase::periodic_clean_up(); } } } void JvmtiEnvBase::record_first_time_class_file_load_hook_enabled() { assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(), "sanity check"); if (!_class_file_load_hook_ever_enabled) { _class_file_load_hook_ever_enabled = true; if (get_capabilities()->can_retransform_classes) { _is_retransformable = true; } else { _is_retransformable = false; // cannot add retransform capability after ClassFileLoadHook has been enabled get_prohibited_capabilities()->can_retransform_classes = 1; } } } void JvmtiEnvBase::record_class_file_load_hook_enabled() { if (!_class_file_load_hook_ever_enabled) { if (Threads::number_of_threads() == 0) { record_first_time_class_file_load_hook_enabled(); } else { MutexLocker mu(JvmtiThreadState_lock); record_first_time_class_file_load_hook_enabled(); } } } jvmtiError JvmtiEnvBase::set_native_method_prefixes(jint prefix_count, char** prefixes) { assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(), "sanity check"); int old_prefix_count = get_native_method_prefix_count(); char **old_prefixes = get_native_method_prefixes(); // allocate and install the new prefixex if (prefix_count == 0 || !is_valid()) { _native_method_prefix_count = 0; _native_method_prefixes = nullptr; } else { // there are prefixes, allocate an array to hold them, and fill it char** new_prefixes = (char**)os::malloc((prefix_count) * sizeof(char*), mtInternal); if (new_prefixes == nullptr) { return JVMTI_ERROR_OUT_OF_MEMORY; } for (int i = 0; i < prefix_count; i++) { char* prefix = prefixes[i]; if (prefix == nullptr) { for (int j = 0; j < (i-1); j++) { os::free(new_prefixes[j]); } os::free(new_prefixes); return JVMTI_ERROR_NULL_POINTER; } prefix = os::strdup(prefixes[i]); if (prefix == nullptr) { for (int j = 0; j < (i-1); j++) { os::free(new_prefixes[j]); } os::free(new_prefixes); return JVMTI_ERROR_OUT_OF_MEMORY; } new_prefixes[i] = prefix; } _native_method_prefix_count = prefix_count; _native_method_prefixes = new_prefixes; } // now that we know the new prefixes have been successfully installed we can // safely remove the old ones if (old_prefix_count != 0) { for (int i = 0; i < old_prefix_count; i++) { os::free(old_prefixes[i]); } os::free(old_prefixes); } return JVMTI_ERROR_NONE; } // Collect all the prefixes which have been set in any JVM TI environments // by the SetNativeMethodPrefix(es) functions. Be sure to maintain the // order of environments and the order of prefixes within each environment. // Return in a resource allocated array. char** JvmtiEnvBase::get_all_native_method_prefixes(int* count_ptr) { assert(Threads::number_of_threads() == 0 || SafepointSynchronize::is_at_safepoint() || JvmtiThreadState_lock->is_locked(), "sanity check"); int total_count = 0; GrowableArray* prefix_array =new GrowableArray(5); JvmtiEnvIterator it; for (JvmtiEnvBase* env = it.first(); env != nullptr; env = it.next(env)) { int prefix_count = env->get_native_method_prefix_count(); char** prefixes = env->get_native_method_prefixes(); for (int j = 0; j < prefix_count; j++) { // retrieve a prefix and so that it is safe against asynchronous changes // copy it into the resource area char* prefix = prefixes[j]; char* prefix_copy = ResourceArea::strdup(prefix); prefix_array->at_put_grow(total_count++, prefix_copy); } } char** all_prefixes = NEW_RESOURCE_ARRAY(char*, total_count); char** p = all_prefixes; for (int i = 0; i < total_count; ++i) { *p++ = prefix_array->at(i); } *count_ptr = total_count; return all_prefixes; } void JvmtiEnvBase::set_event_callbacks(const jvmtiEventCallbacks* callbacks, jint size_of_callbacks) { assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(), "sanity check"); size_t byte_cnt = sizeof(jvmtiEventCallbacks); // clear in either case to be sure we got any gap between sizes memset(&_event_callbacks, 0, byte_cnt); // Now that JvmtiThreadState_lock is held, prevent a possible race condition where events // are re-enabled by a call to set event callbacks where the DisposeEnvironment // occurs after the boiler-plate environment check and before the lock is acquired. if (callbacks != nullptr && is_valid()) { if (size_of_callbacks < (jint)byte_cnt) { byte_cnt = size_of_callbacks; } memcpy(&_event_callbacks, callbacks, byte_cnt); } } // In the fullness of time, all users of the method should instead // directly use allocate, besides being cleaner and faster, this will // mean much better out of memory handling unsigned char * JvmtiEnvBase::jvmtiMalloc(jlong size) { unsigned char* mem = nullptr; jvmtiError result = allocate(size, &mem); assert(result == JVMTI_ERROR_NONE, "Allocate failed"); return mem; } // Handle management jobject JvmtiEnvBase::jni_reference(Handle hndl) { return JNIHandles::make_local(hndl()); } jobject JvmtiEnvBase::jni_reference(JavaThread *thread, Handle hndl) { return JNIHandles::make_local(thread, hndl()); } void JvmtiEnvBase::destroy_jni_reference(jobject jobj) { JNIHandles::destroy_local(jobj); } void JvmtiEnvBase::destroy_jni_reference(JavaThread *thread, jobject jobj) { JNIHandles::destroy_local(jobj); // thread is unused. } // // Threads // jthread * JvmtiEnvBase::new_jthreadArray(int length, Handle *handles) { if (length == 0) { return nullptr; } jthread* objArray = (jthread *) jvmtiMalloc(sizeof(jthread) * length); NULL_CHECK(objArray, nullptr); for (int i = 0; i < length; i++) { objArray[i] = (jthread)jni_reference(handles[i]); } return objArray; } jthreadGroup * JvmtiEnvBase::new_jthreadGroupArray(int length, objArrayHandle groups) { if (length == 0) { return nullptr; } jthreadGroup* objArray = (jthreadGroup *) jvmtiMalloc(sizeof(jthreadGroup) * length); NULL_CHECK(objArray, nullptr); for (int i = 0; i < length; i++) { objArray[i] = (jthreadGroup)JNIHandles::make_local(groups->obj_at(i)); } return objArray; } // Return the vframe on the specified thread and depth, null if no such frame. // The thread and the oops in the returned vframe might not have been processed. javaVFrame* JvmtiEnvBase::jvf_for_thread_and_depth(JavaThread* java_thread, jint depth) { if (!java_thread->has_last_Java_frame()) { return nullptr; } RegisterMap reg_map(java_thread, RegisterMap::UpdateMap::include, RegisterMap::ProcessFrames::skip, RegisterMap::WalkContinuation::include); javaVFrame *jvf = java_thread->last_java_vframe(®_map); jvf = JvmtiEnvBase::check_and_skip_hidden_frames(java_thread, jvf); for (int d = 0; jvf != nullptr && d < depth; d++) { jvf = jvf->java_sender(); } return jvf; } // // utilities: JNI objects // jclass JvmtiEnvBase::get_jni_class_non_null(Klass* k) { assert(k != nullptr, "k != null"); assert(k->is_loader_alive(), "Must be alive"); Thread *thread = Thread::current(); return (jclass)jni_reference(Handle(thread, k->java_mirror())); } // // Field Information // bool JvmtiEnvBase::get_field_descriptor(Klass* k, jfieldID field, fieldDescriptor* fd) { if (!jfieldIDWorkaround::is_valid_jfieldID(k, field)) { return false; } bool found = false; if (jfieldIDWorkaround::is_static_jfieldID(field)) { JNIid* id = jfieldIDWorkaround::from_static_jfieldID(field); found = id->find_local_field(fd); } else { // Non-static field. The fieldID is really the offset of the field within the object. int offset = jfieldIDWorkaround::from_instance_jfieldID(k, field); found = InstanceKlass::cast(k)->find_field_from_offset(offset, false, fd); } return found; } bool JvmtiEnvBase::is_vthread_alive(oop vt) { oop cont = java_lang_VirtualThread::continuation(vt); return !jdk_internal_vm_Continuation::done(cont) && java_lang_VirtualThread::state(vt) != java_lang_VirtualThread::NEW; } // Return JavaThread if virtual thread is mounted, null otherwise. JavaThread* JvmtiEnvBase::get_JavaThread_or_null(oop vthread) { oop carrier_thread = java_lang_VirtualThread::carrier_thread(vthread); if (carrier_thread == nullptr) { return nullptr; } JavaThread* java_thread = java_lang_Thread::thread(carrier_thread); // This could be a different thread to the current one. So we need to ensure that // processing has started before we are allowed to read the continuation oop of // another thread, as it is a direct root of that other thread. StackWatermarkSet::start_processing(java_thread, StackWatermarkKind::gc); oop cont = java_lang_VirtualThread::continuation(vthread); assert(cont != nullptr, "must be"); assert(Continuation::continuation_scope(cont) == java_lang_VirtualThread::vthread_scope(), "must be"); return Continuation::is_continuation_mounted(java_thread, cont) ? java_thread : nullptr; } // An unmounted vthread may have an empty stack. // If unmounted from Java, it always has the yield0() and yield() frames we // need to hide. The methods yield0() and yield() are annotated with the @JvmtiHideEvents. javaVFrame* JvmtiEnvBase::skip_yield_frames_for_unmounted_vthread(oop vthread, javaVFrame* jvf) { if (jvf == nullptr) { return jvf; // empty stack is possible } if (java_lang_VirtualThread::is_preempted(vthread)) { // Top method should not be from Continuation class. assert(jvf->method()->method_holder() != vmClasses::Continuation_klass(), ""); return jvf; } assert(jvf->method()->jvmti_hide_events(), "sanity check"); assert(jvf->method()->method_holder() == vmClasses::Continuation_klass(), "expected Continuation class"); jvf = jvf->java_sender(); // skip yield0 frame assert(jvf != nullptr && jvf->method()->jvmti_hide_events(), "sanity check"); assert(jvf->method()->method_holder() == vmClasses::Continuation_klass(), "expected Continuation class"); jvf = jvf->java_sender(); // skip yield frame return jvf; } // A thread may have an empty stack. // Otherwise, some top frames may heed to be hidden. // Two cases are processed below: // - top frame is annotated with @JvmtiMountTransition: just skip top frames with annotated methods // - JavaThread is in VTMS transition: skip top frames until a frame annotated with @ChangesCurrentThread is found javaVFrame* JvmtiEnvBase::check_and_skip_hidden_frames(bool is_in_VTMS_transition, javaVFrame* jvf) { if (jvf == nullptr) { return jvf; // empty stack is possible } if (jvf->method()->jvmti_mount_transition()) { // Skip frames annotated with @JvmtiMountTransition. for ( ; jvf != nullptr && jvf->method()->jvmti_mount_transition(); jvf = jvf->java_sender()) { } } else if (is_in_VTMS_transition) { // Skip frames above the frame annotated with @ChangesCurrentThread. for ( ; jvf != nullptr && !jvf->method()->changes_current_thread(); jvf = jvf->java_sender()) { } } return jvf; } javaVFrame* JvmtiEnvBase::check_and_skip_hidden_frames(JavaThread* jt, javaVFrame* jvf) { jvf = check_and_skip_hidden_frames(jt->is_in_VTMS_transition(), jvf); return jvf; } javaVFrame* JvmtiEnvBase::get_vthread_jvf(oop vthread) { assert(java_lang_VirtualThread::state(vthread) != java_lang_VirtualThread::NEW, "sanity check"); assert(java_lang_VirtualThread::state(vthread) != java_lang_VirtualThread::TERMINATED, "sanity check"); Thread* cur_thread = Thread::current(); oop cont = java_lang_VirtualThread::continuation(vthread); javaVFrame* jvf = nullptr; JavaThread* java_thread = get_JavaThread_or_null(vthread); if (java_thread != nullptr) { if (!java_thread->has_last_Java_frame()) { // TBD: This is a temporary work around to avoid a guarantee caused by // the native enterSpecial frame on the top. No frames will be found // by the JVMTI functions such as GetStackTrace. return nullptr; } vframeStream vfs(java_thread); assert(!java_thread->is_in_VTMS_transition(), "invariant"); jvf = vfs.at_end() ? nullptr : vfs.asJavaVFrame(); jvf = check_and_skip_hidden_frames(false, jvf); } else { vframeStream vfs(cont); jvf = vfs.at_end() ? nullptr : vfs.asJavaVFrame(); jvf = skip_yield_frames_for_unmounted_vthread(vthread, jvf); } return jvf; } // Return correct javaVFrame for a carrier (non-virtual) thread. // It strips vthread frames at the top if there are any. javaVFrame* JvmtiEnvBase::get_cthread_last_java_vframe(JavaThread* jt, RegisterMap* reg_map_p) { // Strip vthread frames in case of carrier thread with mounted continuation. bool cthread_with_cont = JvmtiEnvBase::is_cthread_with_continuation(jt); javaVFrame *jvf = cthread_with_cont ? jt->carrier_last_java_vframe(reg_map_p) : jt->last_java_vframe(reg_map_p); // Skip hidden frames for carrier threads only. jvf = check_and_skip_hidden_frames(jt, jvf); return jvf; } jint JvmtiEnvBase::get_thread_state_base(oop thread_oop, JavaThread* jt) { jint state = 0; if (thread_oop != nullptr) { // Get most state bits. state = (jint)java_lang_Thread::get_thread_status(thread_oop); } if (jt != nullptr) { // We have a JavaThread* so add more state bits. JavaThreadState jts = jt->thread_state(); if (jt->is_carrier_thread_suspended() || ((jt->jvmti_vthread() == nullptr || jt->jvmti_vthread() == thread_oop) && jt->is_suspended())) { // Suspended non-virtual thread. state |= JVMTI_THREAD_STATE_SUSPENDED; } if (jts == _thread_in_native) { state |= JVMTI_THREAD_STATE_IN_NATIVE; } if (jt->is_interrupted(false)) { state |= JVMTI_THREAD_STATE_INTERRUPTED; } } return state; } jint JvmtiEnvBase::get_thread_state(oop thread_oop, JavaThread* jt) { jint state = 0; if (is_thread_carrying_vthread(jt, thread_oop)) { state = (jint)java_lang_Thread::get_thread_status(thread_oop); // This is for extra safety. Other bits are not expected nor needed. state &= (JVMTI_THREAD_STATE_ALIVE | JVMTI_THREAD_STATE_INTERRUPTED); if (jt->is_carrier_thread_suspended()) { state |= JVMTI_THREAD_STATE_SUSPENDED; } // It's okay for the JVMTI state to be reported as WAITING when waiting // for something other than an Object.wait. So, we treat a thread carrying // a virtual thread as waiting indefinitely which is not runnable. // It is why the RUNNABLE bit is not needed and the WAITING bits are added. state |= JVMTI_THREAD_STATE_WAITING | JVMTI_THREAD_STATE_WAITING_INDEFINITELY; } else { state = get_thread_state_base(thread_oop, jt); } return state; } jint JvmtiEnvBase::get_vthread_state(oop thread_oop, JavaThread* java_thread) { jint state = 0; bool ext_suspended = JvmtiVTSuspender::is_vthread_suspended(thread_oop); jint interrupted = java_lang_Thread::interrupted(thread_oop); if (java_thread != nullptr) { // If virtual thread is blocked on a monitor enter the BLOCKED_ON_MONITOR_ENTER bit // is set for carrier thread instead of virtual. // Other state bits except filtered ones are expected to be the same. oop ct_oop = java_lang_VirtualThread::carrier_thread(thread_oop); jint filtered_bits = JVMTI_THREAD_STATE_SUSPENDED | JVMTI_THREAD_STATE_INTERRUPTED; // This call can trigger a safepoint, so thread_oop must not be used after it. state = get_thread_state_base(ct_oop, java_thread) & ~filtered_bits; } else { int vt_state = java_lang_VirtualThread::state(thread_oop); state = (jint)java_lang_VirtualThread::map_state_to_thread_status(vt_state); } // Ensure the thread has not exited after retrieving suspended/interrupted values. if ((state & JVMTI_THREAD_STATE_ALIVE) != 0) { if (ext_suspended) { state |= JVMTI_THREAD_STATE_SUSPENDED; } if (interrupted) { state |= JVMTI_THREAD_STATE_INTERRUPTED; } } return state; } jint JvmtiEnvBase::get_thread_or_vthread_state(oop thread_oop, JavaThread* java_thread) { jint state = 0; if (java_lang_VirtualThread::is_instance(thread_oop)) { state = JvmtiEnvBase::get_vthread_state(thread_oop, java_thread); } else { state = JvmtiEnvBase::get_thread_state(thread_oop, java_thread); } return state; } jvmtiError JvmtiEnvBase::get_live_threads(JavaThread* current_thread, Handle group_hdl, jint *count_ptr, Handle **thread_objs_p) { jint count = 0; Handle *thread_objs = nullptr; ThreadsListEnumerator tle(current_thread, /* include_jvmti_agent_threads */ true); int nthreads = tle.num_threads(); if (nthreads > 0) { thread_objs = NEW_RESOURCE_ARRAY_RETURN_NULL(Handle, nthreads); NULL_CHECK(thread_objs, JVMTI_ERROR_OUT_OF_MEMORY); for (int i = 0; i < nthreads; i++) { Handle thread = tle.get_threadObj(i); if (thread()->is_a(vmClasses::Thread_klass()) && java_lang_Thread::threadGroup(thread()) == group_hdl()) { thread_objs[count++] = thread; } } } *thread_objs_p = thread_objs; *count_ptr = count; return JVMTI_ERROR_NONE; } jvmtiError JvmtiEnvBase::get_subgroups(JavaThread* current_thread, Handle group_hdl, jint *count_ptr, objArrayHandle *group_objs_p) { // This call collects the strong and weak groups JavaThread* THREAD = current_thread; JvmtiJavaUpcallMark jjum(current_thread); // hide JVMTI events for Java upcall JavaValue result(T_OBJECT); JavaCalls::call_virtual(&result, group_hdl, vmClasses::ThreadGroup_klass(), SymbolTable::new_permanent_symbol("subgroupsAsArray"), vmSymbols::void_threadgroup_array_signature(), THREAD); if (HAS_PENDING_EXCEPTION) { Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); CLEAR_PENDING_EXCEPTION; if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { return JVMTI_ERROR_OUT_OF_MEMORY; } else { return JVMTI_ERROR_INTERNAL; } } assert(result.get_type() == T_OBJECT, "just checking"); objArrayOop groups = (objArrayOop)result.get_oop(); *count_ptr = groups == nullptr ? 0 : groups->length(); *group_objs_p = objArrayHandle(current_thread, groups); return JVMTI_ERROR_NONE; } // // Object Monitor Information // // // Count the number of objects for a lightweight monitor. The hobj // parameter is object that owns the monitor so this routine will // count the number of times the same object was locked by frames // in java_thread. // jint JvmtiEnvBase::count_locked_objects(JavaThread *java_thread, Handle hobj) { jint ret = 0; if (!java_thread->has_last_Java_frame()) { return ret; // no Java frames so no monitors } Thread* current_thread = Thread::current(); ResourceMark rm(current_thread); HandleMark hm(current_thread); RegisterMap reg_map(java_thread, RegisterMap::UpdateMap::include, RegisterMap::ProcessFrames::include, RegisterMap::WalkContinuation::skip); for (javaVFrame *jvf = java_thread->last_java_vframe(®_map); jvf != nullptr; jvf = jvf->java_sender()) { GrowableArray* mons = jvf->monitors(); if (!mons->is_empty()) { for (int i = 0; i < mons->length(); i++) { MonitorInfo *mi = mons->at(i); if (mi->owner_is_scalar_replaced()) continue; // see if owner of the monitor is our object if (mi->owner() != nullptr && mi->owner() == hobj()) { ret++; } } } } return ret; } jvmtiError JvmtiEnvBase::get_current_contended_monitor(JavaThread *calling_thread, JavaThread *java_thread, jobject *monitor_ptr, bool is_virtual) { Thread *current_thread = Thread::current(); assert(java_thread->is_handshake_safe_for(current_thread), "call by myself or at handshake"); if (!is_virtual && JvmtiEnvBase::is_cthread_with_continuation(java_thread)) { // Carrier thread with a mounted continuation case. // No contended monitor can be owned by carrier thread in this case. *monitor_ptr = nullptr; return JVMTI_ERROR_NONE; } oop obj = nullptr; // The ObjectMonitor* can't be async deflated since we are either // at a safepoint or the calling thread is operating on itself so // it cannot leave the underlying wait()/enter() call. ObjectMonitor *mon = java_thread->current_waiting_monitor(); if (mon == nullptr) { // thread is not doing an Object.wait() call mon = java_thread->current_pending_monitor(); if (mon != nullptr) { // The thread is trying to enter() an ObjectMonitor. obj = mon->object(); assert(obj != nullptr, "ObjectMonitor should have a valid object!"); } } else { // thread is doing an Object.wait() call oop thread_oop = get_vthread_or_thread_oop(java_thread); jint state = get_thread_or_vthread_state(thread_oop, java_thread); if (state & JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER) { // thread is re-entering the monitor in an Object.wait() call obj = mon->object(); assert(obj != nullptr, "Object.wait() should have an object"); } } if (obj == nullptr) { *monitor_ptr = nullptr; } else { HandleMark hm(current_thread); Handle hobj(current_thread, obj); *monitor_ptr = jni_reference(calling_thread, hobj); } return JVMTI_ERROR_NONE; } jvmtiError JvmtiEnvBase::get_owned_monitors(JavaThread *calling_thread, JavaThread* java_thread, GrowableArray *owned_monitors_list) { // Note: // calling_thread is the thread that requested the list of monitors for java_thread. // java_thread is the thread owning the monitors. // current_thread is the thread executing this code, can be a non-JavaThread (e.g. VM Thread). // And they all may be different threads. jvmtiError err = JVMTI_ERROR_NONE; Thread *current_thread = Thread::current(); assert(java_thread->is_handshake_safe_for(current_thread), "call by myself or at handshake"); if (JvmtiEnvBase::is_cthread_with_continuation(java_thread)) { // Carrier thread with a mounted continuation case. // No contended monitor can be owned by carrier thread in this case. return JVMTI_ERROR_NONE; } if (java_thread->has_last_Java_frame()) { ResourceMark rm(current_thread); HandleMark hm(current_thread); RegisterMap reg_map(java_thread, RegisterMap::UpdateMap::include, RegisterMap::ProcessFrames::include, RegisterMap::WalkContinuation::skip); int depth = 0; for (javaVFrame *jvf = get_cthread_last_java_vframe(java_thread, ®_map); jvf != nullptr; jvf = jvf->java_sender()) { if (MaxJavaStackTraceDepth == 0 || depth++ < MaxJavaStackTraceDepth) { // check for stack too deep // add locked objects for this frame into list err = get_locked_objects_in_frame(calling_thread, java_thread, jvf, owned_monitors_list, depth-1); if (err != JVMTI_ERROR_NONE) { return err; } } } } // Get off stack monitors. (e.g. acquired via jni MonitorEnter). JvmtiMonitorClosure jmc(calling_thread, owned_monitors_list, this); ObjectSynchronizer::owned_monitors_iterate(&jmc, java_thread); err = jmc.error(); return err; } jvmtiError JvmtiEnvBase::get_owned_monitors(JavaThread* calling_thread, JavaThread* carrier, javaVFrame* jvf, GrowableArray *owned_monitors_list, oop vthread) { jvmtiError err = JVMTI_ERROR_NONE; Thread *current_thread = Thread::current(); assert(carrier == nullptr || carrier->is_handshake_safe_for(current_thread), "call by myself or at handshake"); int depth = 0; for ( ; jvf != nullptr; jvf = jvf->java_sender()) { if (MaxJavaStackTraceDepth == 0 || depth++ < MaxJavaStackTraceDepth) { // check for stack too deep // Add locked objects for this frame into list. err = get_locked_objects_in_frame(calling_thread, carrier, jvf, owned_monitors_list, depth - 1, vthread); if (err != JVMTI_ERROR_NONE) { return err; } } } // Get off stack monitors. (e.g. acquired via jni MonitorEnter). JvmtiMonitorClosure jmc(calling_thread, owned_monitors_list, this); ObjectSynchronizer::owned_monitors_iterate(&jmc, carrier != nullptr ? carrier->threadObj() : vthread); err = jmc.error(); return err; } // Save JNI local handles for any objects that this frame owns. jvmtiError JvmtiEnvBase::get_locked_objects_in_frame(JavaThread* calling_thread, JavaThread* target, javaVFrame *jvf, GrowableArray* owned_monitors_list, jint stack_depth, oop vthread) { jvmtiError err = JVMTI_ERROR_NONE; Thread* current_thread = Thread::current(); ResourceMark rm(current_thread); HandleMark hm(current_thread); GrowableArray* mons = jvf->monitors(); if (mons->is_empty()) { return err; // this javaVFrame holds no monitors } oop wait_obj = nullptr; { // The ObjectMonitor* can't be async deflated since we are either // at a safepoint or the calling thread is operating on itself so // it cannot leave the underlying wait() call. // Save object of current wait() call (if any) for later comparison. if (target != nullptr) { ObjectMonitor *mon = target->current_waiting_monitor(); if (mon != nullptr) wait_obj = mon->object(); } else { ObjectMonitor *mon = java_lang_VirtualThread::current_waiting_monitor(vthread); if (mon != nullptr) wait_obj = mon->object(); } } oop pending_obj = nullptr; { // The ObjectMonitor* can't be async deflated since we are either // at a safepoint or the calling thread is operating on itself so // it cannot leave the underlying enter() call. // Save object of current enter() call (if any) for later comparison. if (target != nullptr) { ObjectMonitor *mon = target->current_pending_monitor(); if (mon != nullptr) pending_obj = mon->object(); } else { ObjectMonitor *mon = java_lang_VirtualThread::current_pending_monitor(vthread); if (mon != nullptr) pending_obj = mon->object(); } } for (int i = 0; i < mons->length(); i++) { MonitorInfo *mi = mons->at(i); if (mi->owner_is_scalar_replaced()) continue; oop obj = mi->owner(); if (obj == nullptr) { // this monitor doesn't have an owning object so skip it continue; } if (wait_obj == obj) { // the thread is waiting on this monitor so it isn't really owned continue; } if (pending_obj == obj) { // the thread is pending on this monitor so it isn't really owned continue; } if (owned_monitors_list->length() > 0) { // Our list has at least one object on it so we have to check // for recursive object locking bool found = false; for (int j = 0; j < owned_monitors_list->length(); j++) { jobject jobj = ((jvmtiMonitorStackDepthInfo*)owned_monitors_list->at(j))->monitor; oop check = JNIHandles::resolve(jobj); if (check == obj) { found = true; // we found the object break; } } if (found) { // already have this object so don't include it continue; } } // add the owning object to our list jvmtiMonitorStackDepthInfo *jmsdi; err = allocate(sizeof(jvmtiMonitorStackDepthInfo), (unsigned char **)&jmsdi); if (err != JVMTI_ERROR_NONE) { return err; } Handle hobj(Thread::current(), obj); jmsdi->monitor = jni_reference(calling_thread, hobj); jmsdi->stack_depth = stack_depth; owned_monitors_list->append(jmsdi); } return err; } jvmtiError JvmtiEnvBase::get_stack_trace(javaVFrame *jvf, jint start_depth, jint max_count, jvmtiFrameInfo* frame_buffer, jint* count_ptr) { Thread *current_thread = Thread::current(); ResourceMark rm(current_thread); HandleMark hm(current_thread); int count = 0; if (start_depth != 0) { if (start_depth > 0) { for (int j = 0; j < start_depth && jvf != nullptr; j++) { jvf = jvf->java_sender(); } if (jvf == nullptr) { // start_depth is deeper than the stack depth. return JVMTI_ERROR_ILLEGAL_ARGUMENT; } } else { // start_depth < 0 // We are referencing the starting depth based on the oldest // part of the stack. // Optimize to limit the number of times that java_sender() is called. javaVFrame *jvf_cursor = jvf; javaVFrame *jvf_prev = nullptr; javaVFrame *jvf_prev_prev = nullptr; int j = 0; while (jvf_cursor != nullptr) { jvf_prev_prev = jvf_prev; jvf_prev = jvf_cursor; for (j = 0; j > start_depth && jvf_cursor != nullptr; j--) { jvf_cursor = jvf_cursor->java_sender(); } } if (j == start_depth) { // Previous pointer is exactly where we want to start. jvf = jvf_prev; } else { // We need to back up further to get to the right place. if (jvf_prev_prev == nullptr) { // The -start_depth is greater than the stack depth. return JVMTI_ERROR_ILLEGAL_ARGUMENT; } // j is now the number of frames on the stack starting with // jvf_prev, we start from jvf_prev_prev and move older on // the stack that many, and the result is -start_depth frames // remaining. jvf = jvf_prev_prev; for (; j < 0; j++) { jvf = jvf->java_sender(); } } } } for (; count < max_count && jvf != nullptr; count++) { frame_buffer[count].method = jvf->method()->jmethod_id(); frame_buffer[count].location = (jvf->method()->is_native() ? -1 : jvf->bci()); jvf = jvf->java_sender(); } *count_ptr = count; return JVMTI_ERROR_NONE; } jvmtiError JvmtiEnvBase::get_stack_trace(JavaThread *java_thread, jint start_depth, jint max_count, jvmtiFrameInfo* frame_buffer, jint* count_ptr) { Thread *current_thread = Thread::current(); assert(SafepointSynchronize::is_at_safepoint() || java_thread->is_handshake_safe_for(current_thread), "call by myself / at safepoint / at handshake"); int count = 0; jvmtiError err = JVMTI_ERROR_NONE; if (java_thread->has_last_Java_frame()) { RegisterMap reg_map(java_thread, RegisterMap::UpdateMap::include, RegisterMap::ProcessFrames::skip, RegisterMap::WalkContinuation::skip); ResourceMark rm(current_thread); javaVFrame *jvf = get_cthread_last_java_vframe(java_thread, ®_map); err = get_stack_trace(jvf, start_depth, max_count, frame_buffer, count_ptr); } else { *count_ptr = 0; if (start_depth != 0) { // no frames and there is a starting depth err = JVMTI_ERROR_ILLEGAL_ARGUMENT; } } return err; } jint JvmtiEnvBase::get_frame_count(javaVFrame *jvf) { int count = 0; while (jvf != nullptr) { jvf = jvf->java_sender(); count++; } return count; } jvmtiError JvmtiEnvBase::get_frame_count(JavaThread* jt, jint *count_ptr) { Thread *current_thread = Thread::current(); assert(current_thread == jt || SafepointSynchronize::is_at_safepoint() || jt->is_handshake_safe_for(current_thread), "call by myself / at safepoint / at handshake"); if (!jt->has_last_Java_frame()) { // no Java frames *count_ptr = 0; } else { ResourceMark rm(current_thread); RegisterMap reg_map(jt, RegisterMap::UpdateMap::include, RegisterMap::ProcessFrames::include, RegisterMap::WalkContinuation::skip); javaVFrame *jvf = get_cthread_last_java_vframe(jt, ®_map); *count_ptr = get_frame_count(jvf); } return JVMTI_ERROR_NONE; } jvmtiError JvmtiEnvBase::get_frame_count(oop vthread_oop, jint *count_ptr) { Thread *current_thread = Thread::current(); ResourceMark rm(current_thread); javaVFrame *jvf = JvmtiEnvBase::get_vthread_jvf(vthread_oop); *count_ptr = get_frame_count(jvf); return JVMTI_ERROR_NONE; } jvmtiError JvmtiEnvBase::get_frame_location(javaVFrame* jvf, jint depth, jmethodID* method_ptr, jlocation* location_ptr) { int cur_depth = 0; while (jvf != nullptr && cur_depth < depth) { jvf = jvf->java_sender(); cur_depth++; } assert(depth >= cur_depth, "ran out of frames too soon"); if (jvf == nullptr) { return JVMTI_ERROR_NO_MORE_FRAMES; } Method* method = jvf->method(); if (method->is_native()) { *location_ptr = -1; } else { *location_ptr = jvf->bci(); } *method_ptr = method->jmethod_id(); return JVMTI_ERROR_NONE; } jvmtiError JvmtiEnvBase::get_frame_location(JavaThread *java_thread, jint depth, jmethodID* method_ptr, jlocation* location_ptr) { Thread* current = Thread::current(); assert(java_thread->is_handshake_safe_for(current), "call by myself or at handshake"); if (!java_thread->has_last_Java_frame()) { return JVMTI_ERROR_NO_MORE_FRAMES; } ResourceMark rm(current); HandleMark hm(current); RegisterMap reg_map(java_thread, RegisterMap::UpdateMap::include, RegisterMap::ProcessFrames::skip, RegisterMap::WalkContinuation::include); javaVFrame* jvf = JvmtiEnvBase::get_cthread_last_java_vframe(java_thread, ®_map); return get_frame_location(jvf, depth, method_ptr, location_ptr); } jvmtiError JvmtiEnvBase::get_frame_location(oop vthread_oop, jint depth, jmethodID* method_ptr, jlocation* location_ptr) { Thread* current = Thread::current(); ResourceMark rm(current); HandleMark hm(current); javaVFrame *jvf = JvmtiEnvBase::get_vthread_jvf(vthread_oop); return get_frame_location(jvf, depth, method_ptr, location_ptr); } jvmtiError JvmtiEnvBase::set_frame_pop(JvmtiThreadState* state, javaVFrame* jvf, jint depth) { for (int d = 0; jvf != nullptr && d < depth; d++) { jvf = jvf->java_sender(); } if (jvf == nullptr) { return JVMTI_ERROR_NO_MORE_FRAMES; } if (jvf->method()->is_native() || (depth == 0 && state->top_frame_is_exiting()) || (state->is_virtual() && jvf->method()->jvmti_hide_events())) { return JVMTI_ERROR_OPAQUE_FRAME; } assert(jvf->frame_pointer() != nullptr, "frame pointer mustn't be null"); int frame_number = (int)get_frame_count(jvf); JvmtiEnvThreadState* ets = state->env_thread_state(this); if (ets->is_frame_pop(frame_number)) { return JVMTI_ERROR_DUPLICATE; } ets->set_frame_pop(frame_number); return JVMTI_ERROR_NONE; } jvmtiError JvmtiEnvBase::clear_all_frame_pops(JvmtiThreadState* state) { JvmtiEnvThreadState* ets = state->env_thread_state(this); ets->clear_all_frame_pops(); return JVMTI_ERROR_NONE; } bool JvmtiEnvBase::is_cthread_with_mounted_vthread(JavaThread* jt) { oop thread_oop = jt->threadObj(); assert(thread_oop != nullptr, "sanity check"); oop mounted_vt = jt->jvmti_vthread(); return mounted_vt != nullptr && mounted_vt != thread_oop; } bool JvmtiEnvBase::is_cthread_with_continuation(JavaThread* jt) { const ContinuationEntry* cont_entry = nullptr; if (jt->has_last_Java_frame()) { cont_entry = jt->vthread_continuation(); } return cont_entry != nullptr && is_cthread_with_mounted_vthread(jt); } // Check if VirtualThread or BoundVirtualThread is suspended. bool JvmtiEnvBase::is_vthread_suspended(oop vt_oop, JavaThread* jt) { bool suspended = false; if (java_lang_VirtualThread::is_instance(vt_oop)) { suspended = JvmtiVTSuspender::is_vthread_suspended(vt_oop); } else if (vt_oop->is_a(vmClasses::BoundVirtualThread_klass())) { suspended = jt->is_suspended(); } return suspended; } // If (thread == null) then return current thread object. // Otherwise return JNIHandles::resolve_external_guard(thread). oop JvmtiEnvBase::current_thread_obj_or_resolve_external_guard(jthread thread) { oop thread_obj = JNIHandles::resolve_external_guard(thread); if (thread == nullptr) { thread_obj = get_vthread_or_thread_oop(JavaThread::current()); } return thread_obj; } jvmtiError JvmtiEnvBase::get_threadOop_and_JavaThread(ThreadsList* t_list, jthread thread, JavaThread* cur_thread, JavaThread** jt_pp, oop* thread_oop_p) { JavaThread* java_thread = nullptr; oop thread_oop = nullptr; if (thread == nullptr) { if (cur_thread == nullptr) { // cur_thread can be null when called from a VM_op return JVMTI_ERROR_INVALID_THREAD; } java_thread = cur_thread; thread_oop = get_vthread_or_thread_oop(java_thread); if (thread_oop == nullptr || !thread_oop->is_a(vmClasses::Thread_klass())) { return JVMTI_ERROR_INVALID_THREAD; } } else { jvmtiError err = JvmtiExport::cv_external_thread_to_JavaThread(t_list, thread, &java_thread, &thread_oop); if (err != JVMTI_ERROR_NONE) { // We got an error code so we don't have a JavaThread*, but only return // an error from here if we didn't get a valid thread_oop. In a vthread case // the cv_external_thread_to_JavaThread is expected to correctly set the // thread_oop and return JVMTI_ERROR_INVALID_THREAD which we ignore here. if (thread_oop == nullptr || err != JVMTI_ERROR_INVALID_THREAD) { *thread_oop_p = thread_oop; return err; } } if (java_thread == nullptr && java_lang_VirtualThread::is_instance(thread_oop)) { java_thread = get_JavaThread_or_null(thread_oop); } } *jt_pp = java_thread; *thread_oop_p = thread_oop; if (java_lang_VirtualThread::is_instance(thread_oop) && !JvmtiEnvBase::is_vthread_alive(thread_oop)) { return JVMTI_ERROR_THREAD_NOT_ALIVE; } return JVMTI_ERROR_NONE; } // Check for JVMTI_ERROR_NOT_SUSPENDED and JVMTI_ERROR_OPAQUE_FRAME errors. // Used in PopFrame and ForceEarlyReturn implementations. jvmtiError JvmtiEnvBase::check_non_suspended_or_opaque_frame(JavaThread* jt, oop thr_obj, bool self) { bool is_virtual = thr_obj != nullptr && thr_obj->is_a(vmClasses::BaseVirtualThread_klass()); if (is_virtual) { if (!is_JavaThread_current(jt, thr_obj)) { if (!is_vthread_suspended(thr_obj, jt)) { return JVMTI_ERROR_THREAD_NOT_SUSPENDED; } if (jt == nullptr) { // unmounted virtual thread return JVMTI_ERROR_OPAQUE_FRAME; } } } else { // platform thread if (!self && !jt->is_suspended() && !jt->is_carrier_thread_suspended()) { return JVMTI_ERROR_THREAD_NOT_SUSPENDED; } } return JVMTI_ERROR_NONE; } jvmtiError JvmtiEnvBase::get_object_monitor_usage(JavaThread* calling_thread, jobject object, jvmtiMonitorUsage* info_ptr) { assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint"); Thread* current_thread = VMThread::vm_thread(); assert(current_thread == Thread::current(), "must be"); HandleMark hm(current_thread); Handle hobj; // Check arguments { oop mirror = JNIHandles::resolve_external_guard(object); NULL_CHECK(mirror, JVMTI_ERROR_INVALID_OBJECT); NULL_CHECK(info_ptr, JVMTI_ERROR_NULL_POINTER); hobj = Handle(current_thread, mirror); } ThreadsListHandle tlh(current_thread); JavaThread *owning_thread = nullptr; jvmtiMonitorUsage ret = { nullptr, 0, 0, nullptr, 0, nullptr }; uint32_t debug_bits = 0; // first derive the object's owner and entry_count (if any) owning_thread = ObjectSynchronizer::get_lock_owner(tlh.list(), hobj); if (owning_thread != nullptr) { oop thread_oop = get_vthread_or_thread_oop(owning_thread); bool is_virtual = thread_oop->is_a(vmClasses::BaseVirtualThread_klass()); if (is_virtual) { thread_oop = nullptr; } Handle th(current_thread, thread_oop); ret.owner = (jthread)jni_reference(calling_thread, th); // The recursions field of a monitor does not reflect recursions // as lightweight locks before inflating the monitor are not included. // We have to count the number of recursive monitor entries the hard way. // We pass a handle to survive any GCs along the way. ret.entry_count = is_virtual ? 0 : count_locked_objects(owning_thread, hobj); } // implied else: entry_count == 0 jint nWant = 0, nWait = 0; markWord mark = hobj->mark(); ResourceMark rm(current_thread); GrowableArray* wantList = nullptr; ObjectMonitor* mon = mark.has_monitor() ? ObjectSynchronizer::read_monitor(current_thread, hobj(), mark) : nullptr; if (mon != nullptr) { // this object has a heavyweight monitor nWant = mon->contentions(); // # of threads contending for monitor entry, but not re-entry nWait = mon->waiters(); // # of threads waiting for notification, // or to re-enter monitor, in Object.wait() // Get the actual set of threads trying to enter, or re-enter, the monitor. wantList = Threads::get_pending_threads(tlh.list(), nWant + nWait, (address)mon); nWant = wantList->length(); } else { // this object has a lightweight monitor } jint skipped = 0; if (mon != nullptr) { // Robustness: the actual waiting list can be smaller. // The nWait count we got from the mon->waiters() may include the re-entering // the monitor threads after being notified. Here we are correcting the actual // number of the waiting threads by excluding those re-entering the monitor. nWait = 0; for (ObjectWaiter* waiter = mon->first_waiter(); waiter != nullptr && (nWait == 0 || waiter != mon->first_waiter()); waiter = mon->next_waiter(waiter)) { JavaThread *w = mon->thread_of_waiter(waiter); if (w == nullptr) { skipped++; } else { oop thread_oop = get_vthread_or_thread_oop(w); if (thread_oop->is_a(vmClasses::BaseVirtualThread_klass())) { skipped++; } } nWait++; } } ret.waiter_count = nWant; ret.notify_waiter_count = nWait - skipped; // Allocate memory for heavyweight and lightweight monitor. jvmtiError err; err = allocate(ret.waiter_count * sizeof(jthread *), (unsigned char**)&ret.waiters); if (err != JVMTI_ERROR_NONE) { return err; } err = allocate(ret.notify_waiter_count * sizeof(jthread *), (unsigned char**)&ret.notify_waiters); if (err != JVMTI_ERROR_NONE) { deallocate((unsigned char*)ret.waiters); return err; } // now derive the rest of the fields if (mon != nullptr) { // this object has a heavyweight monitor // null out memory for robustness if (ret.waiters != nullptr) { memset(ret.waiters, 0, ret.waiter_count * sizeof(jthread *)); } if (ret.notify_waiters != nullptr) { memset(ret.notify_waiters, 0, ret.notify_waiter_count * sizeof(jthread *)); } if (ret.waiter_count > 0) { // we have contending threads waiting to enter/re-enter the monitor // identify threads waiting to enter and re-enter the monitor // get_pending_threads returns only java thread so we do not need to // check for non java threads. for (int i = 0; i < nWant; i++) { JavaThread *pending_thread = wantList->at(i); Handle th(current_thread, get_vthread_or_thread_oop(pending_thread)); ret.waiters[i] = (jthread)jni_reference(calling_thread, th); } } if (ret.notify_waiter_count > 0) { // we have threads waiting to be notified in Object.wait() ObjectWaiter *waiter = mon->first_waiter(); jint skipped = 0; for (int i = 0; i < nWait; i++) { JavaThread *w = mon->thread_of_waiter(waiter); bool is_virtual; if (w == nullptr) { is_virtual = true; } else { oop thread_oop = get_vthread_or_thread_oop(w); is_virtual = thread_oop->is_a(vmClasses::BaseVirtualThread_klass()); } if (is_virtual) { skipped++; } else { // If the thread was found on the ObjectWaiter list, then // it has not been notified. Handle th(current_thread, w->threadObj()); ret.notify_waiters[i - skipped] = (jthread)jni_reference(calling_thread, th); } waiter = mon->next_waiter(waiter); } } } else { // this object has a lightweight monitor and we have nothing more // to do here because the defaults are just fine. } // we don't update return parameter unless everything worked *info_ptr = ret; return JVMTI_ERROR_NONE; } jvmtiError JvmtiEnvBase::check_thread_list(jint count, const jthread* list) { if (list == nullptr && count != 0) { return JVMTI_ERROR_NULL_POINTER; } for (int i = 0; i < count; i++) { jthread thread = list[i]; oop thread_oop = JNIHandles::resolve_external_guard(thread); if (thread_oop == nullptr || !thread_oop->is_a(vmClasses::BaseVirtualThread_klass())) { return JVMTI_ERROR_INVALID_THREAD; } } return JVMTI_ERROR_NONE; } bool JvmtiEnvBase::is_in_thread_list(jint count, const jthread* list, oop jt_oop) { for (int idx = 0; idx < count; idx++) { jthread thread = list[idx]; oop thread_oop = JNIHandles::resolve_external_guard(thread); if (thread_oop == jt_oop) { return true; } } return false; } class VM_SetNotifyJvmtiEventsMode : public VM_Operation { private: bool _enable; static void correct_jvmti_thread_state(JavaThread* jt) { oop ct_oop = jt->threadObj(); oop vt_oop = jt->vthread(); JvmtiThreadState* jt_state = jt->jvmti_thread_state(); JvmtiThreadState* ct_state = java_lang_Thread::jvmti_thread_state(jt->threadObj()); JvmtiThreadState* vt_state = vt_oop != nullptr ? java_lang_Thread::jvmti_thread_state(vt_oop) : nullptr; bool virt = vt_oop != nullptr && java_lang_VirtualThread::is_instance(vt_oop); // Correct jt->jvmti_thread_state() and jt->jvmti_vthread(). // It was not maintained while notifyJvmti was disabled. if (virt) { jt->set_jvmti_thread_state(nullptr); // reset jt->jvmti_thread_state() jt->set_jvmti_vthread(vt_oop); // restore jt->jvmti_vthread() } else { jt->set_jvmti_thread_state(ct_state); // restore jt->jvmti_thread_state() jt->set_jvmti_vthread(ct_oop); // restore jt->jvmti_vthread() } } // This function is called only if _enable == true. // Iterates over all JavaThread's, restores jt->jvmti_thread_state() and // jt->jvmti_vthread() for VTMS transition protocol. void correct_jvmti_thread_states() { for (JavaThread* jt : ThreadsListHandle()) { if (jt->is_in_VTMS_transition()) { jt->set_VTMS_transition_mark(true); continue; // no need in JvmtiThreadState correction below if in transition } correct_jvmti_thread_state(jt); } } public: VMOp_Type type() const { return VMOp_SetNotifyJvmtiEventsMode; } bool allow_nested_vm_operations() const { return false; } VM_SetNotifyJvmtiEventsMode(bool enable) : _enable(enable) { } void doit() { if (_enable) { correct_jvmti_thread_states(); } JvmtiVTMSTransitionDisabler::set_VTMS_notify_jvmti_events(_enable); } }; // This function is to support agents loaded into running VM. // Must be called in thread-in-native mode. bool JvmtiEnvBase::enable_virtual_threads_notify_jvmti() { if (!Continuations::enabled()) { return false; } if (JvmtiVTMSTransitionDisabler::VTMS_notify_jvmti_events()) { return false; // already enabled } VM_SetNotifyJvmtiEventsMode op(true); VMThread::execute(&op); return true; } // This function is used in WhiteBox, only needed to test the function above. // It is unsafe to use this function when virtual threads are executed. // Must be called in thread-in-native mode. bool JvmtiEnvBase::disable_virtual_threads_notify_jvmti() { if (!Continuations::enabled()) { return false; } if (!JvmtiVTMSTransitionDisabler::VTMS_notify_jvmti_events()) { return false; // already disabled } JvmtiVTMSTransitionDisabler disabler(true); // ensure there are no other disablers VM_SetNotifyJvmtiEventsMode op(false); VMThread::execute(&op); return true; } // java_thread - protected by ThreadsListHandle jvmtiError JvmtiEnvBase::suspend_thread(oop thread_oop, JavaThread* java_thread, bool single_suspend) { JavaThread* current = JavaThread::current(); HandleMark hm(current); Handle thread_h(current, thread_oop); bool is_virtual = java_lang_VirtualThread::is_instance(thread_h()); // Unmounted vthread case. if (is_virtual && java_thread == nullptr) { assert(single_suspend, "sanity check"); if (JvmtiVTSuspender::is_vthread_suspended(thread_h())) { return JVMTI_ERROR_THREAD_SUSPENDED; } JvmtiVTSuspender::register_vthread_suspend(thread_h()); return JVMTI_ERROR_NONE; } // Platform thread or mounted vthread cases. assert(java_thread != nullptr, "sanity check"); assert(!java_thread->is_in_VTMS_transition(), "sanity check"); // Don't allow hidden thread suspend request. if (java_thread->is_hidden_from_external_view()) { return JVMTI_ERROR_NONE; } // An attempt to handshake-suspend a thread carrying a virtual thread will result in // suspension of mounted virtual thread. So, we just mark it as suspended // and it will be actually suspended at virtual thread unmount transition. bool is_thread_carrying = is_thread_carrying_vthread(java_thread, thread_h()); if (is_thread_carrying) { return java_thread->set_carrier_thread_suspended() ? JVMTI_ERROR_NONE : JVMTI_ERROR_THREAD_SUSPENDED; } else { // Platform thread (not carrying vthread) or mounted vthread cases. assert(thread_h() != nullptr, "sanity check"); assert(single_suspend || thread_h()->is_a(vmClasses::BaseVirtualThread_klass()), "SuspendAllVirtualThreads should never suspend non-virtual threads"); // Ideally we would just need to check java_thread->is_suspended(), but we have to // consider the case of trying to suspend a thread that was previously suspended while // carrying a vthread but has already unmounted it. if (java_thread->is_suspended() || (!is_virtual && java_thread->is_carrier_thread_suspended())) { return JVMTI_ERROR_THREAD_SUSPENDED; } if (!java_thread->java_suspend(is_virtual && single_suspend)) { // Thread is already suspended or in process of exiting. if (java_thread->is_exiting()) { // The thread was in the process of exiting. return JVMTI_ERROR_THREAD_NOT_ALIVE; } return JVMTI_ERROR_THREAD_SUSPENDED; } return JVMTI_ERROR_NONE; } } // java_thread - protected by ThreadsListHandle jvmtiError JvmtiEnvBase::resume_thread(oop thread_oop, JavaThread* java_thread, bool single_resume) { JavaThread* current = JavaThread::current(); HandleMark hm(current); Handle thread_h(current, thread_oop); bool is_virtual = java_lang_VirtualThread::is_instance(thread_h()); // Unmounted vthread case. if (is_virtual && java_thread == nullptr) { assert(single_resume, "sanity check"); if (!JvmtiVTSuspender::is_vthread_suspended(thread_h())) { return JVMTI_ERROR_THREAD_NOT_SUSPENDED; } JvmtiVTSuspender::register_vthread_resume(thread_h()); return JVMTI_ERROR_NONE; } // Platform thread or mounted vthread cases. assert(java_thread != nullptr, "sanity check"); assert(!java_thread->is_in_VTMS_transition(), "sanity check"); // Don't allow hidden thread resume request. if (java_thread->is_hidden_from_external_view()) { return JVMTI_ERROR_NONE; } bool is_thread_carrying = is_thread_carrying_vthread(java_thread, thread_h()); if (is_thread_carrying) { return java_thread->clear_carrier_thread_suspended() ? JVMTI_ERROR_NONE : JVMTI_ERROR_THREAD_NOT_SUSPENDED; } else { // Platform thread (not carrying vthread) or mounted vthread cases. assert(thread_h() != nullptr, "sanity check"); assert(single_resume || thread_h()->is_a(vmClasses::BaseVirtualThread_klass()), "ResumeAllVirtualThreads should never resume non-virtual threads"); // Ideally we would not have to check this but we have to consider the case // of trying to resume a thread that was previously suspended while carrying // a vthread but has already unmounted it. if (!is_virtual && java_thread->is_carrier_thread_suspended()) { bool res = java_thread->clear_carrier_thread_suspended(); assert(res, "resume operations running concurrently?"); return JVMTI_ERROR_NONE; } if (!java_thread->java_resume(is_virtual && single_resume)) { return JVMTI_ERROR_THREAD_NOT_SUSPENDED; } return JVMTI_ERROR_NONE; } } ResourceTracker::ResourceTracker(JvmtiEnv* env) { _env = env; _allocations = new (mtServiceability) GrowableArray(20, mtServiceability); _failed = false; } ResourceTracker::~ResourceTracker() { if (_failed) { for (int i=0; i<_allocations->length(); i++) { _env->deallocate(_allocations->at(i)); } } delete _allocations; } jvmtiError ResourceTracker::allocate(jlong size, unsigned char** mem_ptr) { unsigned char *ptr; jvmtiError err = _env->allocate(size, &ptr); if (err == JVMTI_ERROR_NONE) { _allocations->append(ptr); *mem_ptr = ptr; } else { *mem_ptr = nullptr; _failed = true; } return err; } unsigned char* ResourceTracker::allocate(jlong size) { unsigned char* ptr; allocate(size, &ptr); return ptr; } char* ResourceTracker::strdup(const char* str) { char *dup_str = (char*)allocate(strlen(str)+1); if (dup_str != nullptr) { strcpy(dup_str, str); } return dup_str; } struct StackInfoNode { struct StackInfoNode *next; jvmtiStackInfo info; }; // Create a jvmtiStackInfo inside a linked list node and create a // buffer for the frame information, both allocated as resource objects. // Fill in both the jvmtiStackInfo and the jvmtiFrameInfo. // Note that either or both of thr and thread_oop // may be null if the thread is new or has exited. void MultipleStackTracesCollector::fill_frames(jthread jt, JavaThread *thr, oop thread_oop) { #ifdef ASSERT Thread *current_thread = Thread::current(); assert(SafepointSynchronize::is_at_safepoint() || thr == nullptr || thr->is_handshake_safe_for(current_thread), "unmounted virtual thread / call by myself / at safepoint / at handshake"); #endif jint state = 0; struct StackInfoNode *node = NEW_RESOURCE_OBJ(struct StackInfoNode); jvmtiStackInfo *infop = &(node->info); node->next = head(); set_head(node); infop->frame_count = 0; infop->frame_buffer = nullptr; infop->thread = jt; if (java_lang_VirtualThread::is_instance(thread_oop)) { state = JvmtiEnvBase::get_vthread_state(thread_oop, thr); if ((state & JVMTI_THREAD_STATE_ALIVE) != 0) { javaVFrame *jvf = JvmtiEnvBase::get_vthread_jvf(thread_oop); infop->frame_buffer = NEW_RESOURCE_ARRAY(jvmtiFrameInfo, max_frame_count()); _result = env()->get_stack_trace(jvf, 0, max_frame_count(), infop->frame_buffer, &(infop->frame_count)); } } else { state = JvmtiEnvBase::get_thread_state(thread_oop, thr); if (thr != nullptr && (state & JVMTI_THREAD_STATE_ALIVE) != 0) { infop->frame_buffer = NEW_RESOURCE_ARRAY(jvmtiFrameInfo, max_frame_count()); _result = env()->get_stack_trace(thr, 0, max_frame_count(), infop->frame_buffer, &(infop->frame_count)); } } _frame_count_total += infop->frame_count; infop->state = state; } // Based on the stack information in the linked list, allocate memory // block to return and fill it from the info in the linked list. void MultipleStackTracesCollector::allocate_and_fill_stacks(jint thread_count) { // do I need to worry about alignment issues? jlong alloc_size = thread_count * sizeof(jvmtiStackInfo) + _frame_count_total * sizeof(jvmtiFrameInfo); env()->allocate(alloc_size, (unsigned char **)&_stack_info); // pointers to move through the newly allocated space as it is filled in jvmtiStackInfo *si = _stack_info + thread_count; // bottom of stack info jvmtiFrameInfo *fi = (jvmtiFrameInfo *)si; // is the top of frame info // copy information in resource area into allocated buffer // insert stack info backwards since linked list is backwards // insert frame info forwards // walk the StackInfoNodes for (struct StackInfoNode *sin = head(); sin != nullptr; sin = sin->next) { jint frame_count = sin->info.frame_count; size_t frames_size = frame_count * sizeof(jvmtiFrameInfo); --si; memcpy(si, &(sin->info), sizeof(jvmtiStackInfo)); if (frames_size == 0) { si->frame_buffer = nullptr; } else { memcpy(fi, sin->info.frame_buffer, frames_size); si->frame_buffer = fi; // point to the new allocated copy of the frames fi += frame_count; } } assert(si == _stack_info, "the last copied stack info must be the first record"); assert((unsigned char *)fi == ((unsigned char *)_stack_info) + alloc_size, "the last copied frame info must be the last record"); } // AdapterClosure is to make use of JvmtiUnitedHandshakeClosure objects from // Handshake::execute() which is unaware of the do_vthread() member functions. class AdapterClosure : public HandshakeClosure { JvmtiUnitedHandshakeClosure* _hs_cl; Handle _target_h; public: AdapterClosure(JvmtiUnitedHandshakeClosure* hs_cl, Handle target_h) : HandshakeClosure(hs_cl->name()), _hs_cl(hs_cl), _target_h(target_h) {} virtual void do_thread(Thread* target) { if (java_lang_VirtualThread::is_instance(_target_h())) { _hs_cl->do_vthread(_target_h); // virtual thread } else { _hs_cl->do_thread(target); // platform thread } } }; // Supports platform and virtual threads. // JvmtiVTMSTransitionDisabler is always set by this function. void JvmtiHandshake::execute(JvmtiUnitedHandshakeClosure* hs_cl, jthread target) { JavaThread* current = JavaThread::current(); HandleMark hm(current); JvmtiVTMSTransitionDisabler disabler(target); ThreadsListHandle tlh(current); JavaThread* java_thread = nullptr; oop thread_obj = nullptr; jvmtiError err = JvmtiEnvBase::get_threadOop_and_JavaThread(tlh.list(), target, current, &java_thread, &thread_obj); if (err != JVMTI_ERROR_NONE) { hs_cl->set_result(err); return; } Handle target_h(current, thread_obj); execute(hs_cl, &tlh, java_thread, target_h); } // Supports platform and virtual threads. // A virtual thread is always identified by the target_h oop handle. // The target_jt is always nullptr for an unmounted virtual thread. // JvmtiVTMSTransitionDisabler has to be set before call to this function. void JvmtiHandshake::execute(JvmtiUnitedHandshakeClosure* hs_cl, ThreadsListHandle* tlh, JavaThread* target_jt, Handle target_h) { JavaThread* current = JavaThread::current(); bool is_virtual = java_lang_VirtualThread::is_instance(target_h()); bool self = target_jt == current; assert(!Continuations::enabled() || self || !is_virtual || current->is_VTMS_transition_disabler(), "sanity check"); hs_cl->set_target_jt(target_jt); // can be needed in the virtual thread case hs_cl->set_is_virtual(is_virtual); // can be needed in the virtual thread case hs_cl->set_self(self); // needed when suspend is required for non-current target thread if (is_virtual) { // virtual thread if (!JvmtiEnvBase::is_vthread_alive(target_h())) { return; } if (target_jt == nullptr) { // unmounted virtual thread hs_cl->do_vthread(target_h); // execute handshake closure callback on current thread directly } } if (target_jt != nullptr) { // mounted virtual or platform thread AdapterClosure acl(hs_cl, target_h); if (self) { // target platform thread is current acl.do_thread(target_jt); // execute handshake closure callback on current thread directly } else { Handshake::execute(&acl, tlh, target_jt); // delegate to Handshake implementation } } } void VM_GetThreadListStackTraces::doit() { assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint"); ResourceMark rm; ThreadsListHandle tlh; for (int i = 0; i < _thread_count; ++i) { jthread jt = _thread_list[i]; JavaThread* java_thread = nullptr; oop thread_oop = nullptr; jvmtiError err = JvmtiEnvBase::get_threadOop_and_JavaThread(tlh.list(), jt, nullptr, &java_thread, &thread_oop); if (err != JVMTI_ERROR_NONE) { // We got an error code so we don't have a JavaThread *, but // only return an error from here if we didn't get a valid // thread_oop. // In the virtual thread case the get_threadOop_and_JavaThread is expected to correctly set // the thread_oop and return JVMTI_ERROR_THREAD_NOT_ALIVE which we ignore here. // The corresponding thread state will be recorded in the jvmtiStackInfo.state. if (thread_oop == nullptr) { _collector.set_result(err); return; } // We have a valid thread_oop. } _collector.fill_frames(jt, java_thread, thread_oop); } _collector.allocate_and_fill_stacks(_thread_count); } void GetSingleStackTraceClosure::doit() { JavaThread *jt = _target_jt; oop thread_oop = JNIHandles::resolve_external_guard(_jthread); if ((jt == nullptr || !jt->is_exiting()) && thread_oop != nullptr) { ResourceMark rm; _collector.fill_frames(_jthread, jt, thread_oop); _collector.allocate_and_fill_stacks(1); set_result(_collector.result()); } } void GetSingleStackTraceClosure::do_thread(Thread *target) { assert(_target_jt == JavaThread::cast(target), "sanity check"); doit(); } void GetSingleStackTraceClosure::do_vthread(Handle target_h) { // Use jvmti_vthread() instead of vthread() as target could have temporarily changed // identity to carrier thread (see VirtualThread.switchToCarrierThread). assert(_target_jt == nullptr || _target_jt->jvmti_vthread() == target_h(), "sanity check"); doit(); } void VM_GetAllStackTraces::doit() { assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint"); ResourceMark rm; _final_thread_count = 0; for (JavaThreadIteratorWithHandle jtiwh; JavaThread *jt = jtiwh.next(); ) { oop thread_oop = jt->threadObj(); if (thread_oop != nullptr && !jt->is_exiting() && java_lang_Thread::is_alive(thread_oop) && !jt->is_hidden_from_external_view() && !thread_oop->is_a(vmClasses::BoundVirtualThread_klass())) { ++_final_thread_count; // Handle block of the calling thread is used to create local refs. _collector.fill_frames((jthread)JNIHandles::make_local(_calling_thread, thread_oop), jt, thread_oop); } } _collector.allocate_and_fill_stacks(_final_thread_count); } // Verifies that the top frame is a java frame in an expected state. // Deoptimizes frame if needed. // Checks that the frame method signature matches the return type (tos). // HandleMark must be defined in the caller only. // It is to keep a ret_ob_h handle alive after return to the caller. jvmtiError JvmtiEnvBase::check_top_frame(Thread* current_thread, JavaThread* java_thread, jvalue value, TosState tos, Handle* ret_ob_h) { ResourceMark rm(current_thread); javaVFrame* jvf = jvf_for_thread_and_depth(java_thread, 0); NULL_CHECK(jvf, JVMTI_ERROR_NO_MORE_FRAMES); if (jvf->method()->is_native()) { return JVMTI_ERROR_OPAQUE_FRAME; } // If the frame is a compiled one, need to deoptimize it. if (jvf->is_compiled_frame()) { if (!jvf->fr().can_be_deoptimized()) { return JVMTI_ERROR_OPAQUE_FRAME; } Deoptimization::deoptimize_frame(java_thread, jvf->fr().id()); } // Get information about method return type Symbol* signature = jvf->method()->signature(); ResultTypeFinder rtf(signature); TosState fr_tos = as_TosState(rtf.type()); if (fr_tos != tos) { if (tos != itos || (fr_tos != btos && fr_tos != ztos && fr_tos != ctos && fr_tos != stos)) { return JVMTI_ERROR_TYPE_MISMATCH; } } // Check that the jobject class matches the return type signature. jobject jobj = value.l; if (tos == atos && jobj != nullptr) { // null reference is allowed Handle ob_h(current_thread, JNIHandles::resolve_external_guard(jobj)); NULL_CHECK(ob_h, JVMTI_ERROR_INVALID_OBJECT); Klass* ob_k = ob_h()->klass(); NULL_CHECK(ob_k, JVMTI_ERROR_INVALID_OBJECT); // Method return type signature. char* ty_sign = 1 + strchr(signature->as_C_string(), JVM_SIGNATURE_ENDFUNC); if (!VM_GetOrSetLocal::is_assignable(ty_sign, ob_k, current_thread)) { return JVMTI_ERROR_TYPE_MISMATCH; } *ret_ob_h = ob_h; } return JVMTI_ERROR_NONE; } /* end check_top_frame */ // ForceEarlyReturn follows the PopFrame approach in many aspects. // Main difference is on the last stage in the interpreter. // The PopFrame stops method execution to continue execution // from the same method call instruction. // The ForceEarlyReturn forces return from method so the execution // continues at the bytecode following the method call. // thread - NOT protected by ThreadsListHandle and NOT pre-checked jvmtiError JvmtiEnvBase::force_early_return(jthread thread, jvalue value, TosState tos) { JavaThread* current_thread = JavaThread::current(); HandleMark hm(current_thread); JvmtiVTMSTransitionDisabler disabler(thread); ThreadsListHandle tlh(current_thread); JavaThread* java_thread = nullptr; oop thread_obj = nullptr; jvmtiError err = get_threadOop_and_JavaThread(tlh.list(), thread, current_thread, &java_thread, &thread_obj); if (err != JVMTI_ERROR_NONE) { return err; } Handle thread_handle(current_thread, thread_obj); bool self = java_thread == current_thread; err = check_non_suspended_or_opaque_frame(java_thread, thread_obj, self); if (err != JVMTI_ERROR_NONE) { return err; } // retrieve or create the state JvmtiThreadState* state = JvmtiThreadState::state_for(java_thread); if (state == nullptr) { return JVMTI_ERROR_THREAD_NOT_ALIVE; } // Eagerly reallocate scalar replaced objects. EscapeBarrier eb(true, current_thread, java_thread); if (!eb.deoptimize_objects(0)) { // Reallocation of scalar replaced objects failed -> return with error return JVMTI_ERROR_OUT_OF_MEMORY; } MutexLocker mu(JvmtiThreadState_lock); SetForceEarlyReturn op(state, value, tos); JvmtiHandshake::execute(&op, &tlh, java_thread, thread_handle); return op.result(); } void SetForceEarlyReturn::doit(Thread *target) { JavaThread* java_thread = JavaThread::cast(target); Thread* current_thread = Thread::current(); HandleMark hm(current_thread); if (java_thread->is_exiting()) { return; /* JVMTI_ERROR_THREAD_NOT_ALIVE (default) */ } // Check to see if a ForceEarlyReturn was already in progress if (_state->is_earlyret_pending()) { // Probably possible for JVMTI clients to trigger this, but the // JPDA backend shouldn't allow this to happen _result = JVMTI_ERROR_INTERNAL; return; } { // The same as for PopFrame. Workaround bug: // 4812902: popFrame hangs if the method is waiting at a synchronize // Catch this condition and return an error to avoid hanging. // Now JVMTI spec allows an implementation to bail out with an opaque // frame error. OSThread* osThread = java_thread->osthread(); if (osThread->get_state() == MONITOR_WAIT) { _result = JVMTI_ERROR_OPAQUE_FRAME; return; } } Handle ret_ob_h; _result = JvmtiEnvBase::check_top_frame(current_thread, java_thread, _value, _tos, &ret_ob_h); if (_result != JVMTI_ERROR_NONE) { return; } assert(_tos != atos || _value.l == nullptr || ret_ob_h() != nullptr, "return object oop must not be null if jobject is not null"); // Update the thread state to reflect that the top frame must be // forced to return. // The current frame will be returned later when the suspended // thread is resumed and right before returning from VM to Java. // (see call_VM_base() in assembler_.cpp). _state->set_earlyret_pending(); _state->set_earlyret_oop(ret_ob_h()); _state->set_earlyret_value(_value, _tos); // Set pending step flag for this early return. // It is cleared when next step event is posted. _state->set_pending_step_for_earlyret(); } void JvmtiMonitorClosure::do_monitor(ObjectMonitor* mon) { if ( _error != JVMTI_ERROR_NONE) { // Error occurred in previous iteration so no need to add // to the list. return; } // Filter out on stack monitors collected during stack walk. oop obj = mon->object(); if (obj == nullptr) { // This can happen if JNI code drops all references to the // owning object. return; } bool found = false; for (int j = 0; j < _owned_monitors_list->length(); j++) { jobject jobj = ((jvmtiMonitorStackDepthInfo*)_owned_monitors_list->at(j))->monitor; oop check = JNIHandles::resolve(jobj); if (check == obj) { // On stack monitor already collected during the stack walk. found = true; break; } } if (found == false) { // This is off stack monitor (e.g. acquired via jni MonitorEnter). jvmtiError err; jvmtiMonitorStackDepthInfo *jmsdi; err = _env->allocate(sizeof(jvmtiMonitorStackDepthInfo), (unsigned char **)&jmsdi); if (err != JVMTI_ERROR_NONE) { _error = err; return; } Handle hobj(Thread::current(), obj); jmsdi->monitor = _env->jni_reference(_calling_thread, hobj); // stack depth is unknown for this monitor. jmsdi->stack_depth = -1; _owned_monitors_list->append(jmsdi); } } GrowableArray* JvmtiModuleClosure::_tbl = nullptr; void JvmtiModuleClosure::do_module(ModuleEntry* entry) { assert_locked_or_safepoint(Module_lock); OopHandle module = entry->module_handle(); guarantee(module.resolve() != nullptr, "module object is null"); _tbl->push(module); } jvmtiError JvmtiModuleClosure::get_all_modules(JvmtiEnv* env, jint* module_count_ptr, jobject** modules_ptr) { ResourceMark rm; MutexLocker mcld(ClassLoaderDataGraph_lock); MutexLocker ml(Module_lock); _tbl = new GrowableArray(77); if (_tbl == nullptr) { return JVMTI_ERROR_OUT_OF_MEMORY; } // Iterate over all the modules loaded to the system. ClassLoaderDataGraph::modules_do_keepalive(&do_module); jint len = _tbl->length(); guarantee(len > 0, "at least one module must be present"); jobject* array = (jobject*)env->jvmtiMalloc((jlong)(len * sizeof(jobject))); if (array == nullptr) { return JVMTI_ERROR_OUT_OF_MEMORY; } for (jint idx = 0; idx < len; idx++) { array[idx] = JNIHandles::make_local(_tbl->at(idx).resolve()); } _tbl = nullptr; *modules_ptr = array; *module_count_ptr = len; return JVMTI_ERROR_NONE; } void UpdateForPopTopFrameClosure::doit(Thread *target) { Thread* current_thread = Thread::current(); HandleMark hm(current_thread); JavaThread* java_thread = JavaThread::cast(target); if (java_thread->is_exiting()) { return; /* JVMTI_ERROR_THREAD_NOT_ALIVE (default) */ } assert(java_thread == _state->get_thread(), "Must be"); // Check to see if a PopFrame was already in progress if (java_thread->popframe_condition() != JavaThread::popframe_inactive) { // Probably possible for JVMTI clients to trigger this, but the // JPDA backend shouldn't allow this to happen _result = JVMTI_ERROR_INTERNAL; return; } // Was workaround bug // 4812902: popFrame hangs if the method is waiting at a synchronize // Catch this condition and return an error to avoid hanging. // Now JVMTI spec allows an implementation to bail out with an opaque frame error. OSThread* osThread = java_thread->osthread(); if (osThread->get_state() == MONITOR_WAIT) { _result = JVMTI_ERROR_OPAQUE_FRAME; return; } ResourceMark rm(current_thread); // Check if there is more than one Java frame in this thread, that the top two frames // are Java (not native) frames, and that there is no intervening VM frame int frame_count = 0; bool is_interpreted[2]; intptr_t *frame_sp[2]; // The 2-nd arg of constructor is needed to stop iterating at java entry frame. for (vframeStream vfs(java_thread, true, false /* process_frames */); !vfs.at_end(); vfs.next()) { methodHandle mh(current_thread, vfs.method()); if (mh->is_native()) { _result = JVMTI_ERROR_OPAQUE_FRAME; return; } is_interpreted[frame_count] = vfs.is_interpreted_frame(); frame_sp[frame_count] = vfs.frame_id(); if (++frame_count > 1) break; } if (frame_count < 2) { // We haven't found two adjacent non-native Java frames on the top. // There can be two situations here: // 1. There are no more java frames // 2. Two top java frames are separated by non-java native frames if (JvmtiEnvBase::jvf_for_thread_and_depth(java_thread, 1) == nullptr) { _result = JVMTI_ERROR_NO_MORE_FRAMES; return; } else { // Intervening non-java native or VM frames separate java frames. // Current implementation does not support this. See bug #5031735. // In theory it is possible to pop frames in such cases. _result = JVMTI_ERROR_OPAQUE_FRAME; return; } } // If any of the top 2 frames is a compiled one, need to deoptimize it for (int i = 0; i < 2; i++) { if (!is_interpreted[i]) { Deoptimization::deoptimize_frame(java_thread, frame_sp[i]); } } // Update the thread state to reflect that the top frame is popped // so that cur_stack_depth is maintained properly and all frameIDs // are invalidated. // The current frame will be popped later when the suspended thread // is resumed and right before returning from VM to Java. // (see call_VM_base() in assembler_.cpp). // It's fine to update the thread state here because no JVMTI events // shall be posted for this PopFrame. _state->update_for_pop_top_frame(); java_thread->set_popframe_condition(JavaThread::popframe_pending_bit); // Set pending step flag for this popframe and it is cleared when next // step event is posted. _state->set_pending_step_for_popframe(); _result = JVMTI_ERROR_NONE; } void SetOrClearFramePopClosure::do_thread(Thread *target) { Thread* current = Thread::current(); ResourceMark rm(current); // vframes are resource allocated JavaThread* java_thread = JavaThread::cast(target); if (java_thread->is_exiting()) { return; // JVMTI_ERROR_THREAD_NOT_ALIVE (default) } if (!_self && !java_thread->is_suspended()) { _result = JVMTI_ERROR_THREAD_NOT_SUSPENDED; return; } if (!_set) { // ClearAllFramePops _result = _env->clear_all_frame_pops(_state); return; } if (!java_thread->has_last_Java_frame()) { _result = JVMTI_ERROR_NO_MORE_FRAMES; return; } assert(_state->get_thread_or_saved() == java_thread, "Must be"); RegisterMap reg_map(java_thread, RegisterMap::UpdateMap::include, RegisterMap::ProcessFrames::skip, RegisterMap::WalkContinuation::include); javaVFrame* jvf = JvmtiEnvBase::get_cthread_last_java_vframe(java_thread, ®_map); _result = _env->set_frame_pop(_state, jvf, _depth); } void SetOrClearFramePopClosure::do_vthread(Handle target_h) { Thread* current = Thread::current(); ResourceMark rm(current); // vframes are resource allocated if (!_self && !JvmtiVTSuspender::is_vthread_suspended(target_h())) { _result = JVMTI_ERROR_THREAD_NOT_SUSPENDED; return; } if (!_set) { // ClearAllFramePops _result = _env->clear_all_frame_pops(_state); return; } javaVFrame *jvf = JvmtiEnvBase::get_vthread_jvf(target_h()); _result = _env->set_frame_pop(_state, jvf, _depth); } void GetOwnedMonitorInfoClosure::do_thread(Thread *target) { JavaThread *jt = JavaThread::cast(target); if (!jt->is_exiting() && (jt->threadObj() != nullptr)) { _result = ((JvmtiEnvBase *)_env)->get_owned_monitors(_calling_thread, jt, _owned_monitors_list); } } void GetOwnedMonitorInfoClosure::do_vthread(Handle target_h) { Thread* current = Thread::current(); ResourceMark rm(current); // vframes are resource allocated HandleMark hm(current); javaVFrame *jvf = JvmtiEnvBase::get_vthread_jvf(target_h()); if (_target_jt == nullptr || (!_target_jt->is_exiting() && _target_jt->threadObj() != nullptr)) { _result = ((JvmtiEnvBase *)_env)->get_owned_monitors(_calling_thread, _target_jt, jvf, _owned_monitors_list, target_h()); } } void GetCurrentContendedMonitorClosure::do_thread(Thread *target) { JavaThread *jt = JavaThread::cast(target); if (!jt->is_exiting() && (jt->threadObj() != nullptr)) { _result = ((JvmtiEnvBase *)_env)->get_current_contended_monitor(_calling_thread, jt, _owned_monitor_ptr, _is_virtual); } } void GetCurrentContendedMonitorClosure::do_vthread(Handle target_h) { if (_target_jt == nullptr) { ObjectMonitor *mon = java_lang_VirtualThread::current_pending_monitor(target_h()); if (mon != nullptr) { *_owned_monitor_ptr = JNIHandles::make_local(_calling_thread, mon->object()); } _result = JVMTI_ERROR_NONE; // target virtual thread is unmounted return; } // mounted virtual thread case do_thread(_target_jt); } void GetStackTraceClosure::do_thread(Thread *target) { Thread* current = Thread::current(); ResourceMark rm(current); JavaThread *jt = JavaThread::cast(target); if (!jt->is_exiting() && jt->threadObj() != nullptr) { _result = ((JvmtiEnvBase *)_env)->get_stack_trace(jt, _start_depth, _max_count, _frame_buffer, _count_ptr); } } void GetStackTraceClosure::do_vthread(Handle target_h) { Thread* current = Thread::current(); ResourceMark rm(current); javaVFrame *jvf = JvmtiEnvBase::get_vthread_jvf(target_h()); _result = ((JvmtiEnvBase *)_env)->get_stack_trace(jvf, _start_depth, _max_count, _frame_buffer, _count_ptr); } #ifdef ASSERT void PrintStackTraceClosure::do_thread_impl(Thread *target) { JavaThread *java_thread = JavaThread::cast(target); Thread *current_thread = Thread::current(); ResourceMark rm (current_thread); const char* tname = JvmtiTrace::safe_get_thread_name(java_thread); oop t_oop = java_thread->jvmti_vthread(); t_oop = t_oop == nullptr ? java_thread->threadObj() : t_oop; bool is_vt_suspended = java_lang_VirtualThread::is_instance(t_oop) && JvmtiVTSuspender::is_vthread_suspended(t_oop); log_error(jvmti)("%s(%s) exiting: %d is_susp: %d is_thread_susp: %d is_vthread_susp: %d " "is_VTMS_transition_disabler: %d, is_in_VTMS_transition = %d\n", tname, java_thread->name(), java_thread->is_exiting(), java_thread->is_suspended(), java_thread->is_carrier_thread_suspended(), is_vt_suspended, java_thread->is_VTMS_transition_disabler(), java_thread->is_in_VTMS_transition()); if (java_thread->has_last_Java_frame()) { RegisterMap reg_map(java_thread, RegisterMap::UpdateMap::include, RegisterMap::ProcessFrames::include, RegisterMap::WalkContinuation::skip); ResourceMark rm(current_thread); HandleMark hm(current_thread); javaVFrame *jvf = java_thread->last_java_vframe(®_map); while (jvf != nullptr) { log_error(jvmti)(" %s:%d", jvf->method()->external_name(), jvf->method()->line_number_from_bci(jvf->bci())); jvf = jvf->java_sender(); } } log_error(jvmti)("\n"); } void PrintStackTraceClosure::do_thread(Thread *target) { JavaThread *java_thread = JavaThread::cast(target); Thread *current_thread = Thread::current(); assert(SafepointSynchronize::is_at_safepoint() || java_thread->is_handshake_safe_for(current_thread), "call by myself / at safepoint / at handshake"); PrintStackTraceClosure::do_thread_impl(target); } #endif void GetFrameCountClosure::do_thread(Thread *target) { JavaThread* jt = JavaThread::cast(target); assert(target == jt, "just checking"); if (!jt->is_exiting() && jt->threadObj() != nullptr) { _result = ((JvmtiEnvBase*)_env)->get_frame_count(jt, _count_ptr); } } void GetFrameCountClosure::do_vthread(Handle target_h) { _result = ((JvmtiEnvBase*)_env)->get_frame_count(target_h(), _count_ptr); } void GetFrameLocationClosure::do_thread(Thread *target) { JavaThread *jt = JavaThread::cast(target); assert(target == jt, "just checking"); if (!jt->is_exiting() && jt->threadObj() != nullptr) { _result = ((JvmtiEnvBase*)_env)->get_frame_location(jt, _depth, _method_ptr, _location_ptr); } } void GetFrameLocationClosure::do_vthread(Handle target_h) { _result = ((JvmtiEnvBase*)_env)->get_frame_location(target_h(), _depth, _method_ptr, _location_ptr); }