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/*
* Copyright (c) 2003, 2022, 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 "precompiled.hpp"
#include "classfile/classLoaderDataGraph.hpp"
#include "classfile/javaClasses.inline.hpp"
#include "classfile/moduleEntry.hpp"
#include "classfile/symbolTable.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/threads.hpp"
#include "runtime/threadSMR.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 = NULL;
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 = NULL;
for (JvmtiEnvBase* env = it.first(); env != NULL; env = it.next(env)) {
previous_env = env;
}
if (previous_env == NULL) {
_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() {
jint 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 = NULL;
_tag_map = NULL;
_native_method_prefix_count = 0;
_native_method_prefixes = NULL;
_next = NULL;
_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));
// 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 != NULL ? &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, NULL);
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 != NULL) {
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(NULL);
// A tag map can be big, deallocate it now
if (tag_map_to_deallocate != NULL) {
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 = NULL;
JvmtiEnvBase* env = it.first();
while (env != NULL) {
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 == NULL) {
_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 = NULL;
} 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 == NULL) {
return JVMTI_ERROR_OUT_OF_MEMORY;
}
for (int i = 0; i < prefix_count; i++) {
char* prefix = prefixes[i];
if (prefix == NULL) {
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 == NULL) {
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<char*>* prefix_array =new GrowableArray<char*>(5);
JvmtiEnvIterator it;
for (JvmtiEnvBase* env = it.first(); env != NULL; 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 = NEW_RESOURCE_ARRAY(char, strlen(prefix)+1);
strcpy(prefix_copy, 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 != NULL && 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 = NULL;
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 NULL;
}
jthread* objArray = (jthread *) jvmtiMalloc(sizeof(jthread) * length);
NULL_CHECK(objArray, NULL);
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 NULL;
}
jthreadGroup* objArray = (jthreadGroup *) jvmtiMalloc(sizeof(jthreadGroup) * length);
NULL_CHECK(objArray, NULL);
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 NULL;
}
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 != NULL && d < depth; d++) {
jvf = jvf->java_sender();
}
return jvf;
}
//
// utilities: JNI objects
//
jclass
JvmtiEnvBase::get_jni_class_non_null(Klass* k) {
assert(k != NULL, "k != NULL");
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) {
return java_lang_VirtualThread::state(vt) != java_lang_VirtualThread::NEW &&
java_lang_VirtualThread::state(vt) != java_lang_VirtualThread::TERMINATED;
}
// 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 == NULL) {
return NULL;
}
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 != NULL, "must be");
assert(Continuation::continuation_scope(cont) == java_lang_VirtualThread::vthread_scope(), "must be");
return Continuation::is_continuation_mounted(java_thread, cont) ? java_thread : NULL;
}
javaVFrame*
JvmtiEnvBase::check_and_skip_hidden_frames(bool is_in_VTMS_transition, javaVFrame* jvf) {
// The second condition is needed to hide notification methods.
if (!is_in_VTMS_transition && (jvf == NULL || !jvf->method()->jvmti_mount_transition())) {
return jvf; // No frames to skip.
}
// Find jvf with a method annotated with @JvmtiMountTransition.
for ( ; jvf != NULL; jvf = jvf->java_sender()) {
if (jvf->method()->jvmti_mount_transition()) { // Cannot actually appear in an unmounted continuation; they're never frozen.
jvf = jvf->java_sender(); // Skip annotated method.
break;
}
if (jvf->method()->changes_current_thread()) {
break;
}
// Skip frame above annotated method.
}
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::check_and_skip_hidden_frames(oop vthread, javaVFrame* jvf) {
JvmtiThreadState* state = java_lang_Thread::jvmti_thread_state(vthread);
if (state == NULL) {
// nothing to skip
return jvf;
}
jvf = check_and_skip_hidden_frames(state->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 = NULL;
JavaThread* java_thread = get_JavaThread_or_null(vthread);
if (java_thread != NULL) {
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 NULL;
}
vframeStream vfs(java_thread);
jvf = vfs.at_end() ? NULL : vfs.asJavaVFrame();
jvf = check_and_skip_hidden_frames(java_thread, jvf);
} else {
vframeStream vfs(cont);
jvf = vfs.at_end() ? NULL : vfs.asJavaVFrame();
jvf = check_and_skip_hidden_frames(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 only for carrier threads
// which are in non-temporary VTMS transition.
if (jt->is_in_VTMS_transition()) {
jvf = check_and_skip_hidden_frames(jt, jvf);
}
return jvf;
}
jint
JvmtiEnvBase::get_thread_state(oop thread_oop, JavaThread* jt) {
jint state = 0;
if (thread_oop != NULL) {
// Get most state bits.
state = (jint)java_lang_Thread::get_thread_status(thread_oop);
}
if (jt != NULL) {
// We have a JavaThread* so add more state bits.
JavaThreadState jts = jt->thread_state();
if (jt->is_carrier_thread_suspended() ||
((jt->jvmti_vthread() == NULL || 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_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 != NULL) {
// 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(ct_oop, java_thread) & ~filtered_bits;
} else {
jshort vt_state = java_lang_VirtualThread::state(thread_oop);
state = (jint)java_lang_VirtualThread::map_state_to_thread_status(vt_state);
}
if (ext_suspended && ((state & JVMTI_THREAD_STATE_ALIVE) != 0)) {
state &= ~java_lang_VirtualThread::RUNNING;
state |= JVMTI_THREAD_STATE_ALIVE | JVMTI_THREAD_STATE_RUNNABLE | JVMTI_THREAD_STATE_SUSPENDED;
}
if (interrupted) {
state |= JVMTI_THREAD_STATE_INTERRUPTED;
}
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 = NULL;
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;
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 != NULL;
jvf = jvf->java_sender()) {
GrowableArray<MonitorInfo*>* 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() != NULL && 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 = NULL;
// 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 == NULL) {
// thread is not doing an Object.wait() call
mon = java_thread->current_pending_monitor();
if (mon != NULL) {
// The thread is trying to enter() an ObjectMonitor.
obj = mon->object();
assert(obj != NULL, "ObjectMonitor should have a valid object!");
}
// implied else: no contended ObjectMonitor
} else {
// thread is doing an Object.wait() call
obj = mon->object();
assert(obj != NULL, "Object.wait() should have an object");
}
if (obj == NULL) {
*monitor_ptr = NULL;
} 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<jvmtiMonitorStackDepthInfo*> *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 != NULL; 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::monitors_iterate(&jmc, java_thread);
err = jmc.error();
return err;
}
jvmtiError
JvmtiEnvBase::get_owned_monitors(JavaThread* calling_thread, JavaThread* java_thread, javaVFrame* jvf,
GrowableArray<jvmtiMonitorStackDepthInfo*> *owned_monitors_list) {
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");
int depth = 0;
for ( ; jvf != NULL; 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::monitors_iterate(&jmc, java_thread);
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* java_thread,
javaVFrame *jvf, GrowableArray<jvmtiMonitorStackDepthInfo*>* owned_monitors_list, jint stack_depth) {
jvmtiError err = JVMTI_ERROR_NONE;
Thread* current_thread = Thread::current();
ResourceMark rm(current_thread);
HandleMark hm(current_thread);
GrowableArray<MonitorInfo*>* mons = jvf->monitors();
if (mons->is_empty()) {
return err; // this javaVFrame holds no monitors
}
oop wait_obj = NULL;
{
// 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.
ObjectMonitor *mon = java_thread->current_waiting_monitor();
if (mon != NULL) {
wait_obj = mon->object();
}
}
oop pending_obj = NULL;
{
// 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.
ObjectMonitor *mon = java_thread->current_pending_monitor();
if (mon != NULL) {
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 == NULL) {
// 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 != NULL; j++) {
jvf = jvf->java_sender();
}
if (jvf == NULL) {
// 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 = NULL;
javaVFrame *jvf_prev_prev = NULL;
int j = 0;
while (jvf_cursor != NULL) {
jvf_prev_prev = jvf_prev;
jvf_prev = jvf_cursor;
for (j = 0; j > start_depth && jvf_cursor != NULL; 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 == NULL) {
// 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 != NULL; 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 != NULL) {
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) {
if (!JvmtiEnvBase::is_vthread_alive(vthread_oop)) {
return JVMTI_ERROR_THREAD_NOT_ALIVE;
}
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 != NULL && cur_depth < depth) {
jvf = jvf->java_sender();
cur_depth++;
}
assert(depth >= cur_depth, "ran out of frames too soon");
if (jvf == NULL) {
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) {
if (!JvmtiEnvBase::is_vthread_alive(vthread_oop)) {
return JVMTI_ERROR_THREAD_NOT_ALIVE;
}
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 != NULL && d < depth; d++) {
jvf = jvf->java_sender();
}
if (jvf == NULL) {
return JVMTI_ERROR_NO_MORE_FRAMES;
}
if (jvf->method()->is_native()) {
return JVMTI_ERROR_OPAQUE_FRAME;
}
assert(jvf->frame_pointer() != NULL, "frame pointer mustn't be NULL");
int frame_number = (int)get_frame_count(jvf);
state->env_thread_state((JvmtiEnvBase*)this)->set_frame_pop(frame_number);
return JVMTI_ERROR_NONE;
}
bool
JvmtiEnvBase::is_cthread_with_mounted_vthread(JavaThread* jt) {
oop thread_oop = jt->threadObj();
assert(thread_oop != NULL, "sanity check");
oop mounted_vt = jt->jvmti_vthread();
return mounted_vt != NULL && mounted_vt != thread_oop;
}
bool
JvmtiEnvBase::is_cthread_with_continuation(JavaThread* jt) {
const ContinuationEntry* cont_entry = NULL;
if (jt->has_last_Java_frame()) {
cont_entry = jt->vthread_continuation();
}
return cont_entry != NULL && is_cthread_with_mounted_vthread(jt);
}
// 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 == NULL) {
thread_obj = get_vthread_or_thread_oop(JavaThread::current());
}
return thread_obj;
}
jvmtiError
JvmtiEnvBase::get_threadOop_and_JavaThread(ThreadsList* t_list, jthread thread,
JavaThread** jt_pp, oop* thread_oop_p) {
JavaThread* cur_thread = JavaThread::current();
JavaThread* java_thread = NULL;
oop thread_oop = NULL;
if (thread == NULL) {
java_thread = cur_thread;
thread_oop = get_vthread_or_thread_oop(java_thread);
if (thread_oop == NULL || !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 == NULL || err != JVMTI_ERROR_INVALID_THREAD) {
*thread_oop_p = thread_oop;
return err;
}
}
if (java_thread == NULL && 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;
}
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 = NULL;
ObjectMonitor *mon = NULL;
jvmtiMonitorUsage ret = {
NULL, 0, 0, NULL, 0, NULL
};
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 != NULL) {
Handle th(current_thread, get_vthread_or_thread_oop(owning_thread));
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 = count_locked_objects(owning_thread, hobj);
}
// implied else: entry_count == 0
jint nWant = 0, nWait = 0;
markWord mark = hobj->mark();
if (mark.has_monitor()) {
mon = mark.monitor();
assert(mon != NULL, "must have monitor");
// this object has a heavyweight monitor
nWant = mon->contentions(); // # of threads contending for monitor
nWait = mon->waiters(); // # of threads in Object.wait()
ret.waiter_count = nWant + nWait;
ret.notify_waiter_count = nWait;
} else {
// this object has a lightweight monitor
ret.waiter_count = 0;
ret.notify_waiter_count = 0;
}
// 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 != NULL) {
// this object has a heavyweight monitor
// Number of waiters may actually be less than the waiter count.
// So NULL out memory so that unused memory will be NULL.
memset(ret.waiters, 0, ret.waiter_count * sizeof(jthread *));
memset(ret.notify_waiters, 0, ret.notify_waiter_count * sizeof(jthread *));
if (ret.waiter_count > 0) {
// we have contending and/or waiting threads
if (nWant > 0) {
// we have contending threads
ResourceMark rm(current_thread);
// get_pending_threads returns only java thread so we do not need to
// check for non java threads.
GrowableArray<JavaThread*>* wantList = Threads::get_pending_threads(tlh.list(), nWant, (address)mon);
if (wantList->length() < nWant) {
// robustness: the pending list has gotten smaller
nWant = wantList->length();
}
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 (nWait > 0) {
// we have threads in Object.wait()
int offset = nWant; // add after any contending threads
ObjectWaiter *waiter = mon->first_waiter();
for (int i = 0, j = 0; i < nWait; i++) {
if (waiter == NULL) {
// robustness: the waiting list has gotten smaller
nWait = j;
break;
}
JavaThread *w = mon->thread_of_waiter(waiter);
if (w != NULL) {
// If the thread was found on the ObjectWaiter list, then
// it has not been notified. This thread can't change the
// state of the monitor so it doesn't need to be suspended.
Handle th(current_thread, get_vthread_or_thread_oop(w));
ret.waiters[offset + j] = (jthread)jni_reference(calling_thread, th);
ret.notify_waiters[j++] = (jthread)jni_reference(calling_thread, th);
}
waiter = mon->next_waiter(waiter);
}
}
} // ThreadsListHandle is destroyed here.
// Adjust count. nWant and nWait count values may be less than original.
ret.waiter_count = nWant + nWait;
ret.notify_waiter_count = nWait;
} 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 == NULL && 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 == NULL || !thread_oop->is_a(vmClasses::VirtualThread_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;
}
// java_thread - protected by ThreadsListHandle
jvmtiError
JvmtiEnvBase::suspend_thread(oop thread_oop, JavaThread* java_thread, bool single_suspend,
int* need_safepoint_p) {
JavaThread* current = JavaThread::current();
HandleMark hm(current);
Handle thread_h(current, thread_oop);
bool is_virtual = java_lang_VirtualThread::is_instance(thread_h());
if (is_virtual) {
if (single_suspend) {
if (JvmtiVTSuspender::is_vthread_suspended(thread_h())) {
return JVMTI_ERROR_THREAD_SUSPENDED;
}
JvmtiVTSuspender::register_vthread_suspend(thread_h());
// Check if virtual thread is mounted and there is a java_thread.
// A non-NULL java_thread is always passed in the !single_suspend case.
oop carrier_thread = java_lang_VirtualThread::carrier_thread(thread_h());
java_thread = carrier_thread == NULL ? NULL : java_lang_Thread::thread(carrier_thread);
}
// The java_thread can be still blocked in VTMS transition after a previous JVMTI resume call.
// There is no need to suspend the java_thread in this case. After vthread unblocking,
// it will check for ext_suspend request and suspend itself if necessary.
if (java_thread == NULL || java_thread->is_suspended()) {
// We are done if the virtual thread is unmounted or
// the java_thread is externally suspended.
return JVMTI_ERROR_NONE;
}
// The virtual thread is mounted: suspend the java_thread.
}
// Don't allow hidden thread suspend request.
if (java_thread->is_hidden_from_external_view()) {
return JVMTI_ERROR_NONE;
}
bool is_passive_cthread = is_passive_carrier_thread(java_thread, thread_h());
// A case of non-virtual thread.
if (!is_virtual) {
// Thread.suspend() is used in some tests. It sets jt->is_suspended() only.
if (java_thread->is_carrier_thread_suspended() ||
(!is_passive_cthread && java_thread->is_suspended())) {
return JVMTI_ERROR_THREAD_SUSPENDED;
}
java_thread->set_carrier_thread_suspended();
}
assert(!java_thread->is_in_VTMS_transition(), "sanity check");
assert(!single_suspend || (!is_virtual && java_thread->is_carrier_thread_suspended()) ||
(is_virtual && JvmtiVTSuspender::is_vthread_suspended(thread_h())),
"sanity check");
// An attempt to handshake-suspend a passive carrier 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.
if (!is_passive_cthread) {
assert(single_suspend || is_virtual, "SuspendAllVirtualThreads should never suspend non-virtual threads");
// Case of mounted virtual or attached carrier thread.
if (!JvmtiSuspendControl::suspend(java_thread)) {
// 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());
if (is_virtual) {
if (single_resume) {
if (!JvmtiVTSuspender::is_vthread_suspended(thread_h())) {
return JVMTI_ERROR_THREAD_NOT_SUSPENDED;
}
JvmtiVTSuspender::register_vthread_resume(thread_h());
// Check if virtual thread is mounted and there is a java_thread.
// A non-NULL java_thread is always passed in the !single_resume case.
oop carrier_thread = java_lang_VirtualThread::carrier_thread(thread_h());
java_thread = carrier_thread == NULL ? NULL : java_lang_Thread::thread(carrier_thread);
}
// The java_thread can be still blocked in VTMS transition after a previous JVMTI suspend call.
// There is no need to resume the java_thread in this case. After vthread unblocking,
// it will check for is_vthread_suspended request and remain resumed if necessary.
if (java_thread == NULL || !java_thread->is_suspended()) {
// We are done if the virtual thread is unmounted or
// the java_thread is not externally suspended.
return JVMTI_ERROR_NONE;
}
// The virtual thread is mounted and java_thread is supended: resume the java_thread.
}
// Don't allow hidden thread resume request.
if (java_thread->is_hidden_from_external_view()) {
return JVMTI_ERROR_NONE;
}
bool is_passive_cthread = is_passive_carrier_thread(java_thread, thread_h());
// A case of a non-virtual thread.
if (!is_virtual) {
if (!java_thread->is_carrier_thread_suspended() &&
(is_passive_cthread || !java_thread->is_suspended())) {
return JVMTI_ERROR_THREAD_NOT_SUSPENDED;
}
java_thread->clear_carrier_thread_suspended();
}
assert(!java_thread->is_in_VTMS_transition(), "sanity check");
if (!is_passive_cthread) {
assert(single_resume || is_virtual, "ResumeAllVirtualThreads should never resume non-virtual threads");
if (java_thread->is_suspended()) {
if (!JvmtiSuspendControl::resume(java_thread)) {
return JVMTI_ERROR_THREAD_NOT_SUSPENDED;
}
}
}
return JVMTI_ERROR_NONE;
}
ResourceTracker::ResourceTracker(JvmtiEnv* env) {
_env = env;
_allocations = new (mtServiceability) GrowableArray<unsigned char*>(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 = NULL;
_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 != NULL) {
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 == NULL ||
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 = NULL;
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 != NULL && (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 != NULL; 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 = NULL;
} 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");
}
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 = NULL;
oop thread_oop = NULL;
jvmtiError err = JvmtiExport::cv_external_thread_to_JavaThread(tlh.list(), jt, &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 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 == NULL) {
_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::do_thread(Thread *target) {
JavaThread *jt = JavaThread::cast(target);
oop thread_oop = jt->threadObj();
if (!jt->is_exiting() && thread_oop != NULL) {
ResourceMark rm;
_collector.fill_frames(_jthread, jt, thread_oop);
_collector.allocate_and_fill_stacks(1);
}
}
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 != NULL &&
!jt->is_exiting() &&
java_lang_Thread::is_alive(thread_oop) &&
!jt->is_hidden_from_external_view()) {
++_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 != NULL) { // 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<type> 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
--> --------------------
--> maximum size reached
--> --------------------
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