1 /*
2 * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/classLoaderDataGraph.hpp"
27 #include "classfile/javaClasses.inline.hpp"
28 #include "classfile/moduleEntry.hpp"
29 #include "classfile/symbolTable.hpp"
30 #include "classfile/vmSymbols.hpp"
31 #include "jvmtifiles/jvmtiEnv.hpp"
32 #include "memory/iterator.hpp"
33 #include "memory/resourceArea.hpp"
34 #include "oops/klass.inline.hpp"
35 #include "oops/objArrayKlass.hpp"
36 #include "oops/objArrayOop.hpp"
37 #include "oops/oop.inline.hpp"
38 #include "oops/oopHandle.inline.hpp"
39 #include "prims/jvmtiEnvBase.hpp"
40 #include "prims/jvmtiEventController.inline.hpp"
41 #include "prims/jvmtiExtensions.hpp"
42 #include "prims/jvmtiImpl.hpp"
43 #include "prims/jvmtiManageCapabilities.hpp"
44 #include "prims/jvmtiTagMap.hpp"
45 #include "prims/jvmtiThreadState.inline.hpp"
46 #include "runtime/continuationEntry.inline.hpp"
47 #include "runtime/deoptimization.hpp"
48 #include "runtime/frame.inline.hpp"
49 #include "runtime/handles.inline.hpp"
50 #include "runtime/interfaceSupport.inline.hpp"
51 #include "runtime/javaCalls.hpp"
52 #include "runtime/javaThread.inline.hpp"
53 #include "runtime/jfieldIDWorkaround.hpp"
54 #include "runtime/jniHandles.inline.hpp"
55 #include "runtime/objectMonitor.inline.hpp"
56 #include "runtime/osThread.hpp"
57 #include "runtime/signature.hpp"
58 #include "runtime/stackWatermarkSet.inline.hpp"
59 #include "runtime/synchronizer.inline.hpp"
60 #include "runtime/threads.hpp"
61 #include "runtime/threadSMR.inline.hpp"
62 #include "runtime/vframe.inline.hpp"
63 #include "runtime/vframe_hp.hpp"
64 #include "runtime/vmThread.hpp"
65 #include "runtime/vmOperations.hpp"
66 #include "services/threadService.hpp"
67
68
69 ///////////////////////////////////////////////////////////////
70 //
71 // JvmtiEnvBase
72 //
73
74 JvmtiEnvBase* JvmtiEnvBase::_head_environment = nullptr;
75
76 bool JvmtiEnvBase::_globally_initialized = false;
77 volatile bool JvmtiEnvBase::_needs_clean_up = false;
78
79 jvmtiPhase JvmtiEnvBase::_phase = JVMTI_PHASE_PRIMORDIAL;
80
81 volatile int JvmtiEnvBase::_dying_thread_env_iteration_count = 0;
82
83 extern jvmtiInterface_1_ jvmti_Interface;
84 extern jvmtiInterface_1_ jvmtiTrace_Interface;
85
86
87 // perform initializations that must occur before any JVMTI environments
88 // are released but which should only be initialized once (no matter
89 // how many environments are created).
90 void
91 JvmtiEnvBase::globally_initialize() {
92 assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(), "sanity check");
93 assert(_globally_initialized == false, "bad call");
94
95 JvmtiManageCapabilities::initialize();
96
97 // register extension functions and events
98 JvmtiExtensions::register_extensions();
99
100 #ifdef JVMTI_TRACE
101 JvmtiTrace::initialize();
102 #endif
103
104 _globally_initialized = true;
105 }
106
107
108 void
109 JvmtiEnvBase::initialize() {
110 assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(), "sanity check");
111
112 // Add this environment to the end of the environment list (order is important)
113 {
114 // This block of code must not contain any safepoints, as list deallocation
115 // (which occurs at a safepoint) cannot occur simultaneously with this list
116 // addition. Note: NoSafepointVerifier cannot, currently, be used before
117 // threads exist.
118 JvmtiEnvIterator it;
119 JvmtiEnvBase *previous_env = nullptr;
120 for (JvmtiEnvBase* env = it.first(); env != nullptr; env = it.next(env)) {
121 previous_env = env;
122 }
123 if (previous_env == nullptr) {
124 _head_environment = this;
125 } else {
126 previous_env->set_next_environment(this);
127 }
128 }
129
130 if (_globally_initialized == false) {
131 globally_initialize();
132 }
133 }
134
135 jvmtiPhase
136 JvmtiEnvBase::phase() {
137 // For the JVMTI environments possessed the can_generate_early_vmstart:
138 // replace JVMTI_PHASE_PRIMORDIAL with JVMTI_PHASE_START
139 if (_phase == JVMTI_PHASE_PRIMORDIAL &&
140 JvmtiExport::early_vmstart_recorded() &&
141 early_vmstart_env()) {
142 return JVMTI_PHASE_START;
143 }
144 return _phase; // Normal case
145 }
146
147 bool
148 JvmtiEnvBase::is_valid() {
149 jlong value = 0;
150
151 // This object might not be a JvmtiEnvBase so we can't assume
152 // the _magic field is properly aligned. Get the value in a safe
153 // way and then check against JVMTI_MAGIC.
154
155 switch (sizeof(_magic)) {
156 case 2:
157 value = Bytes::get_native_u2((address)&_magic);
158 break;
159
160 case 4:
161 value = Bytes::get_native_u4((address)&_magic);
162 break;
163
164 case 8:
165 value = Bytes::get_native_u8((address)&_magic);
166 break;
167
168 default:
169 guarantee(false, "_magic field is an unexpected size");
170 }
171
172 return value == JVMTI_MAGIC;
173 }
174
175
176 bool
177 JvmtiEnvBase::use_version_1_0_semantics() {
178 int major, minor, micro;
179
180 JvmtiExport::decode_version_values(_version, &major, &minor, µ);
181 return major == 1 && minor == 0; // micro version doesn't matter here
182 }
183
184
185 bool
186 JvmtiEnvBase::use_version_1_1_semantics() {
187 int major, minor, micro;
188
189 JvmtiExport::decode_version_values(_version, &major, &minor, µ);
190 return major == 1 && minor == 1; // micro version doesn't matter here
191 }
192
193 bool
194 JvmtiEnvBase::use_version_1_2_semantics() {
195 int major, minor, micro;
196
197 JvmtiExport::decode_version_values(_version, &major, &minor, µ);
198 return major == 1 && minor == 2; // micro version doesn't matter here
199 }
200
201
202 JvmtiEnvBase::JvmtiEnvBase(jint version) : _env_event_enable() {
203 _version = version;
204 _env_local_storage = nullptr;
205 _tag_map = nullptr;
206 _native_method_prefix_count = 0;
207 _native_method_prefixes = nullptr;
208 _next = nullptr;
209 _class_file_load_hook_ever_enabled = false;
210
211 // Moot since ClassFileLoadHook not yet enabled.
212 // But "true" will give a more predictable ClassFileLoadHook behavior
213 // for environment creation during ClassFileLoadHook.
214 _is_retransformable = true;
215
216 // all callbacks initially null
217 memset(&_event_callbacks, 0, sizeof(jvmtiEventCallbacks));
218 memset(&_ext_event_callbacks, 0, sizeof(jvmtiExtEventCallbacks));
219
220 // all capabilities initially off
221 memset(&_current_capabilities, 0, sizeof(_current_capabilities));
222
223 // all prohibited capabilities initially off
224 memset(&_prohibited_capabilities, 0, sizeof(_prohibited_capabilities));
225
226 _magic = JVMTI_MAGIC;
227
228 JvmtiEventController::env_initialize((JvmtiEnv*)this);
229
230 #ifdef JVMTI_TRACE
231 _jvmti_external.functions = TraceJVMTI != nullptr ? &jvmtiTrace_Interface : &jvmti_Interface;
232 #else
233 _jvmti_external.functions = &jvmti_Interface;
234 #endif
235 }
236
237
238 void
239 JvmtiEnvBase::dispose() {
240
241 #ifdef JVMTI_TRACE
242 JvmtiTrace::shutdown();
243 #endif
244
245 // Dispose of event info and let the event controller call us back
246 // in a locked state (env_dispose, below)
247 JvmtiEventController::env_dispose(this);
248 }
249
250 void
251 JvmtiEnvBase::env_dispose() {
252 assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(), "sanity check");
253
254 // We have been entered with all events disabled on this environment.
255 // A race to re-enable events (by setting callbacks) is prevented by
256 // checking for a valid environment when setting callbacks (while
257 // holding the JvmtiThreadState_lock).
258
259 // Mark as invalid.
260 _magic = DISPOSED_MAGIC;
261
262 // Relinquish all capabilities.
263 jvmtiCapabilities *caps = get_capabilities();
264 JvmtiManageCapabilities::relinquish_capabilities(caps, caps, caps);
265
266 // Same situation as with events (see above)
267 set_native_method_prefixes(0, nullptr);
268
269 JvmtiTagMap* tag_map_to_clear = tag_map_acquire();
270 // A tag map can be big, clear it now to save memory until
271 // the destructor runs.
272 if (tag_map_to_clear != nullptr) {
273 tag_map_to_clear->clear();
274 }
275
276 _needs_clean_up = true;
277 }
278
279
280 JvmtiEnvBase::~JvmtiEnvBase() {
281 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
282
283 // There is a small window of time during which the tag map of a
284 // disposed environment could have been reallocated.
285 // Make sure it is gone.
286 JvmtiTagMap* tag_map_to_deallocate = _tag_map;
287 set_tag_map(nullptr);
288 // A tag map can be big, deallocate it now
289 if (tag_map_to_deallocate != nullptr) {
290 delete tag_map_to_deallocate;
291 }
292
293 _magic = BAD_MAGIC;
294 }
295
296
297 void
298 JvmtiEnvBase::periodic_clean_up() {
299 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
300
301 // JvmtiEnvBase reference is saved in JvmtiEnvThreadState. So
302 // clean up JvmtiThreadState before deleting JvmtiEnv pointer.
303 JvmtiThreadState::periodic_clean_up();
304
305 // Unlink all invalid environments from the list of environments
306 // and deallocate them
307 JvmtiEnvIterator it;
308 JvmtiEnvBase* previous_env = nullptr;
309 JvmtiEnvBase* env = it.first();
310 while (env != nullptr) {
311 if (env->is_valid()) {
312 previous_env = env;
313 env = it.next(env);
314 } else {
315 // This one isn't valid, remove it from the list and deallocate it
316 JvmtiEnvBase* defunct_env = env;
317 env = it.next(env);
318 if (previous_env == nullptr) {
319 _head_environment = env;
320 } else {
321 previous_env->set_next_environment(env);
322 }
323 delete defunct_env;
324 }
325 }
326
327 }
328
329
330 void
331 JvmtiEnvBase::check_for_periodic_clean_up() {
332 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
333
334 class ThreadInsideIterationClosure: public ThreadClosure {
335 private:
336 bool _inside;
337 public:
338 ThreadInsideIterationClosure() : _inside(false) {};
339
340 void do_thread(Thread* thread) {
341 _inside |= thread->is_inside_jvmti_env_iteration();
342 }
343
344 bool is_inside_jvmti_env_iteration() {
345 return _inside;
346 }
347 };
348
349 if (_needs_clean_up) {
350 // Check if we are currently iterating environment,
351 // deallocation should not occur if we are
352 ThreadInsideIterationClosure tiic;
353 Threads::threads_do(&tiic);
354 if (!tiic.is_inside_jvmti_env_iteration() &&
355 !is_inside_dying_thread_env_iteration()) {
356 _needs_clean_up = false;
357 JvmtiEnvBase::periodic_clean_up();
358 }
359 }
360 }
361
362
363 void
364 JvmtiEnvBase::record_first_time_class_file_load_hook_enabled() {
365 assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(),
366 "sanity check");
367
368 if (!_class_file_load_hook_ever_enabled) {
369 _class_file_load_hook_ever_enabled = true;
370
371 if (get_capabilities()->can_retransform_classes) {
372 _is_retransformable = true;
373 } else {
374 _is_retransformable = false;
375
376 // cannot add retransform capability after ClassFileLoadHook has been enabled
377 get_prohibited_capabilities()->can_retransform_classes = 1;
378 }
379 }
380 }
381
382
383 void
384 JvmtiEnvBase::record_class_file_load_hook_enabled() {
385 if (!_class_file_load_hook_ever_enabled) {
386 if (Threads::number_of_threads() == 0) {
387 record_first_time_class_file_load_hook_enabled();
388 } else {
389 MutexLocker mu(JvmtiThreadState_lock);
390 record_first_time_class_file_load_hook_enabled();
391 }
392 }
393 }
394
395
396 jvmtiError
397 JvmtiEnvBase::set_native_method_prefixes(jint prefix_count, char** prefixes) {
398 assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(),
399 "sanity check");
400
401 int old_prefix_count = get_native_method_prefix_count();
402 char **old_prefixes = get_native_method_prefixes();
403
404 // allocate and install the new prefixex
405 if (prefix_count == 0 || !is_valid()) {
406 _native_method_prefix_count = 0;
407 _native_method_prefixes = nullptr;
408 } else {
409 // there are prefixes, allocate an array to hold them, and fill it
410 char** new_prefixes = (char**)os::malloc((prefix_count) * sizeof(char*), mtInternal);
411 if (new_prefixes == nullptr) {
412 return JVMTI_ERROR_OUT_OF_MEMORY;
413 }
414 for (int i = 0; i < prefix_count; i++) {
415 char* prefix = prefixes[i];
416 if (prefix == nullptr) {
417 for (int j = 0; j < (i-1); j++) {
418 os::free(new_prefixes[j]);
419 }
420 os::free(new_prefixes);
421 return JVMTI_ERROR_NULL_POINTER;
422 }
423 prefix = os::strdup(prefixes[i]);
424 if (prefix == nullptr) {
425 for (int j = 0; j < (i-1); j++) {
426 os::free(new_prefixes[j]);
427 }
428 os::free(new_prefixes);
429 return JVMTI_ERROR_OUT_OF_MEMORY;
430 }
431 new_prefixes[i] = prefix;
432 }
433 _native_method_prefix_count = prefix_count;
434 _native_method_prefixes = new_prefixes;
435 }
436
437 // now that we know the new prefixes have been successfully installed we can
438 // safely remove the old ones
439 if (old_prefix_count != 0) {
440 for (int i = 0; i < old_prefix_count; i++) {
441 os::free(old_prefixes[i]);
442 }
443 os::free(old_prefixes);
444 }
445
446 return JVMTI_ERROR_NONE;
447 }
448
449
450 // Collect all the prefixes which have been set in any JVM TI environments
451 // by the SetNativeMethodPrefix(es) functions. Be sure to maintain the
452 // order of environments and the order of prefixes within each environment.
453 // Return in a resource allocated array.
454 char**
455 JvmtiEnvBase::get_all_native_method_prefixes(int* count_ptr) {
456 assert(Threads::number_of_threads() == 0 ||
457 SafepointSynchronize::is_at_safepoint() ||
458 JvmtiThreadState_lock->is_locked(),
459 "sanity check");
460
461 int total_count = 0;
462 GrowableArray<char*>* prefix_array =new GrowableArray<char*>(5);
463
464 JvmtiEnvIterator it;
465 for (JvmtiEnvBase* env = it.first(); env != nullptr; env = it.next(env)) {
466 int prefix_count = env->get_native_method_prefix_count();
467 char** prefixes = env->get_native_method_prefixes();
468 for (int j = 0; j < prefix_count; j++) {
469 // retrieve a prefix and so that it is safe against asynchronous changes
470 // copy it into the resource area
471 char* prefix = prefixes[j];
472 char* prefix_copy = NEW_RESOURCE_ARRAY(char, strlen(prefix)+1);
473 strcpy(prefix_copy, prefix);
474 prefix_array->at_put_grow(total_count++, prefix_copy);
475 }
476 }
477
478 char** all_prefixes = NEW_RESOURCE_ARRAY(char*, total_count);
479 char** p = all_prefixes;
480 for (int i = 0; i < total_count; ++i) {
481 *p++ = prefix_array->at(i);
482 }
483 *count_ptr = total_count;
484 return all_prefixes;
485 }
486
487 void
488 JvmtiEnvBase::set_event_callbacks(const jvmtiEventCallbacks* callbacks,
489 jint size_of_callbacks) {
490 assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(), "sanity check");
491
492 size_t byte_cnt = sizeof(jvmtiEventCallbacks);
493
494 // clear in either case to be sure we got any gap between sizes
495 memset(&_event_callbacks, 0, byte_cnt);
496
497 // Now that JvmtiThreadState_lock is held, prevent a possible race condition where events
498 // are re-enabled by a call to set event callbacks where the DisposeEnvironment
499 // occurs after the boiler-plate environment check and before the lock is acquired.
500 if (callbacks != nullptr && is_valid()) {
501 if (size_of_callbacks < (jint)byte_cnt) {
502 byte_cnt = size_of_callbacks;
503 }
504 memcpy(&_event_callbacks, callbacks, byte_cnt);
505 }
506 }
507
508
509 // In the fullness of time, all users of the method should instead
510 // directly use allocate, besides being cleaner and faster, this will
511 // mean much better out of memory handling
512 unsigned char *
513 JvmtiEnvBase::jvmtiMalloc(jlong size) {
514 unsigned char* mem = nullptr;
515 jvmtiError result = allocate(size, &mem);
516 assert(result == JVMTI_ERROR_NONE, "Allocate failed");
517 return mem;
518 }
519
520
521 // Handle management
522
523 jobject JvmtiEnvBase::jni_reference(Handle hndl) {
524 return JNIHandles::make_local(hndl());
525 }
526
527 jobject JvmtiEnvBase::jni_reference(JavaThread *thread, Handle hndl) {
528 return JNIHandles::make_local(thread, hndl());
529 }
530
531 void JvmtiEnvBase::destroy_jni_reference(jobject jobj) {
532 JNIHandles::destroy_local(jobj);
533 }
534
535 void JvmtiEnvBase::destroy_jni_reference(JavaThread *thread, jobject jobj) {
536 JNIHandles::destroy_local(jobj); // thread is unused.
537 }
538
539 //
540 // Threads
541 //
542
543 jthread *
544 JvmtiEnvBase::new_jthreadArray(int length, Handle *handles) {
545 if (length == 0) {
546 return nullptr;
547 }
548
549 jthread* objArray = (jthread *) jvmtiMalloc(sizeof(jthread) * length);
550 NULL_CHECK(objArray, nullptr);
551
552 for (int i = 0; i < length; i++) {
553 objArray[i] = (jthread)jni_reference(handles[i]);
554 }
555 return objArray;
556 }
557
558 jthreadGroup *
559 JvmtiEnvBase::new_jthreadGroupArray(int length, objArrayHandle groups) {
560 if (length == 0) {
561 return nullptr;
562 }
563
564 jthreadGroup* objArray = (jthreadGroup *) jvmtiMalloc(sizeof(jthreadGroup) * length);
565 NULL_CHECK(objArray, nullptr);
566
567 for (int i = 0; i < length; i++) {
568 objArray[i] = (jthreadGroup)JNIHandles::make_local(groups->obj_at(i));
569 }
570 return objArray;
571 }
572
573 // Return the vframe on the specified thread and depth, null if no such frame.
574 // The thread and the oops in the returned vframe might not have been processed.
575 javaVFrame*
576 JvmtiEnvBase::jvf_for_thread_and_depth(JavaThread* java_thread, jint depth) {
577 if (!java_thread->has_last_Java_frame()) {
578 return nullptr;
579 }
580 RegisterMap reg_map(java_thread,
581 RegisterMap::UpdateMap::include,
582 RegisterMap::ProcessFrames::skip,
583 RegisterMap::WalkContinuation::include);
584 javaVFrame *jvf = java_thread->last_java_vframe(®_map);
585
586 jvf = JvmtiEnvBase::check_and_skip_hidden_frames(java_thread, jvf);
587
588 for (int d = 0; jvf != nullptr && d < depth; d++) {
589 jvf = jvf->java_sender();
590 }
591 return jvf;
592 }
593
594 //
595 // utilities: JNI objects
596 //
597
598
599 jclass
600 JvmtiEnvBase::get_jni_class_non_null(Klass* k) {
601 assert(k != nullptr, "k != null");
602 assert(k->is_loader_alive(), "Must be alive");
603 Thread *thread = Thread::current();
604 return (jclass)jni_reference(Handle(thread, k->java_mirror()));
605 }
606
607 //
608 // Field Information
609 //
610
611 bool
612 JvmtiEnvBase::get_field_descriptor(Klass* k, jfieldID field, fieldDescriptor* fd) {
613 if (!jfieldIDWorkaround::is_valid_jfieldID(k, field)) {
614 return false;
615 }
616 bool found = false;
617 if (jfieldIDWorkaround::is_static_jfieldID(field)) {
618 JNIid* id = jfieldIDWorkaround::from_static_jfieldID(field);
619 found = id->find_local_field(fd);
620 } else {
621 // Non-static field. The fieldID is really the offset of the field within the object.
622 int offset = jfieldIDWorkaround::from_instance_jfieldID(k, field);
623 found = InstanceKlass::cast(k)->find_field_from_offset(offset, false, fd);
624 }
625 return found;
626 }
627
628 bool
629 JvmtiEnvBase::is_vthread_alive(oop vt) {
630 oop cont = java_lang_VirtualThread::continuation(vt);
631 return !jdk_internal_vm_Continuation::done(cont) &&
632 java_lang_VirtualThread::state(vt) != java_lang_VirtualThread::NEW;
633 }
634
635 // Return JavaThread if virtual thread is mounted, null otherwise.
636 JavaThread* JvmtiEnvBase::get_JavaThread_or_null(oop vthread) {
637 oop carrier_thread = java_lang_VirtualThread::carrier_thread(vthread);
638 if (carrier_thread == nullptr) {
639 return nullptr;
640 }
641
642 JavaThread* java_thread = java_lang_Thread::thread(carrier_thread);
643
644 // This could be a different thread to the current one. So we need to ensure that
645 // processing has started before we are allowed to read the continuation oop of
646 // another thread, as it is a direct root of that other thread.
647 StackWatermarkSet::start_processing(java_thread, StackWatermarkKind::gc);
648
649 oop cont = java_lang_VirtualThread::continuation(vthread);
650 assert(cont != nullptr, "must be");
651 assert(Continuation::continuation_scope(cont) == java_lang_VirtualThread::vthread_scope(), "must be");
652 return Continuation::is_continuation_mounted(java_thread, cont) ? java_thread : nullptr;
653 }
654
655 javaVFrame*
656 JvmtiEnvBase::check_and_skip_hidden_frames(bool is_in_VTMS_transition, javaVFrame* jvf) {
657 // The second condition is needed to hide notification methods.
658 if (!is_in_VTMS_transition && (jvf == nullptr || !jvf->method()->jvmti_mount_transition())) {
659 return jvf; // No frames to skip.
660 }
661 // Find jvf with a method annotated with @JvmtiMountTransition.
662 for ( ; jvf != nullptr; jvf = jvf->java_sender()) {
663 if (jvf->method()->jvmti_mount_transition()) { // Cannot actually appear in an unmounted continuation; they're never frozen.
664 jvf = jvf->java_sender(); // Skip annotated method.
665 break;
666 }
667 if (jvf->method()->changes_current_thread()) {
668 break;
669 }
670 // Skip frame above annotated method.
671 }
672 return jvf;
673 }
674
675 javaVFrame*
676 JvmtiEnvBase::check_and_skip_hidden_frames(JavaThread* jt, javaVFrame* jvf) {
677 jvf = check_and_skip_hidden_frames(jt->is_in_VTMS_transition(), jvf);
678 return jvf;
679 }
680
681 javaVFrame*
682 JvmtiEnvBase::check_and_skip_hidden_frames(oop vthread, javaVFrame* jvf) {
683 JvmtiThreadState* state = java_lang_Thread::jvmti_thread_state(vthread);
684 if (state == nullptr) {
685 // nothing to skip
686 return jvf;
687 }
688 jvf = check_and_skip_hidden_frames(java_lang_Thread::is_in_VTMS_transition(vthread), jvf);
689 return jvf;
690 }
691
692 javaVFrame*
693 JvmtiEnvBase::get_vthread_jvf(oop vthread) {
694 assert(java_lang_VirtualThread::state(vthread) != java_lang_VirtualThread::NEW, "sanity check");
695 assert(java_lang_VirtualThread::state(vthread) != java_lang_VirtualThread::TERMINATED, "sanity check");
696
697 Thread* cur_thread = Thread::current();
698 oop cont = java_lang_VirtualThread::continuation(vthread);
699 javaVFrame* jvf = nullptr;
700
701 JavaThread* java_thread = get_JavaThread_or_null(vthread);
702 if (java_thread != nullptr) {
703 if (!java_thread->has_last_Java_frame()) {
704 // TBD: This is a temporary work around to avoid a guarantee caused by
705 // the native enterSpecial frame on the top. No frames will be found
706 // by the JVMTI functions such as GetStackTrace.
707 return nullptr;
708 }
709 vframeStream vfs(java_thread);
710 jvf = vfs.at_end() ? nullptr : vfs.asJavaVFrame();
711 jvf = check_and_skip_hidden_frames(java_thread, jvf);
712 } else {
713 vframeStream vfs(cont);
714 jvf = vfs.at_end() ? nullptr : vfs.asJavaVFrame();
715 jvf = check_and_skip_hidden_frames(vthread, jvf);
716 }
717 return jvf;
718 }
719
720 // Return correct javaVFrame for a carrier (non-virtual) thread.
721 // It strips vthread frames at the top if there are any.
722 javaVFrame*
723 JvmtiEnvBase::get_cthread_last_java_vframe(JavaThread* jt, RegisterMap* reg_map_p) {
724 // Strip vthread frames in case of carrier thread with mounted continuation.
725 bool cthread_with_cont = JvmtiEnvBase::is_cthread_with_continuation(jt);
726 javaVFrame *jvf = cthread_with_cont ? jt->carrier_last_java_vframe(reg_map_p)
727 : jt->last_java_vframe(reg_map_p);
728 // Skip hidden frames only for carrier threads
729 // which are in non-temporary VTMS transition.
730 if (jt->is_in_VTMS_transition()) {
731 jvf = check_and_skip_hidden_frames(jt, jvf);
732 }
733 return jvf;
734 }
735
736 jint
737 JvmtiEnvBase::get_thread_state_base(oop thread_oop, JavaThread* jt) {
738 jint state = 0;
739
740 if (thread_oop != nullptr) {
741 // Get most state bits.
742 state = (jint)java_lang_Thread::get_thread_status(thread_oop);
743 }
744 if (jt != nullptr) {
745 // We have a JavaThread* so add more state bits.
746 JavaThreadState jts = jt->thread_state();
747
748 if (jt->is_carrier_thread_suspended() ||
749 ((jt->jvmti_vthread() == nullptr || jt->jvmti_vthread() == thread_oop) && jt->is_suspended())) {
750 // Suspended non-virtual thread.
751 state |= JVMTI_THREAD_STATE_SUSPENDED;
752 }
753 if (jts == _thread_in_native) {
754 state |= JVMTI_THREAD_STATE_IN_NATIVE;
755 }
756 if (jt->is_interrupted(false)) {
757 state |= JVMTI_THREAD_STATE_INTERRUPTED;
758 }
759 }
760 return state;
761 }
762
763 jint
764 JvmtiEnvBase::get_thread_state(oop thread_oop, JavaThread* jt) {
765 jint state = 0;
766
767 if (is_thread_carrying_vthread(jt, thread_oop)) {
768 state = (jint)java_lang_Thread::get_thread_status(thread_oop);
769
770 // This is for extra safety. Other bits are not expected nor needed.
771 state &= (JVMTI_THREAD_STATE_ALIVE | JVMTI_THREAD_STATE_INTERRUPTED);
772
773 if (jt->is_carrier_thread_suspended()) {
774 state |= JVMTI_THREAD_STATE_SUSPENDED;
775 }
776 // It's okay for the JVMTI state to be reported as WAITING when waiting
777 // for something other than an Object.wait. So, we treat a thread carrying
778 // a virtual thread as waiting indefinitely which is not runnable.
779 // It is why the RUNNABLE bit is not needed and the WAITING bits are added.
780 state |= JVMTI_THREAD_STATE_WAITING | JVMTI_THREAD_STATE_WAITING_INDEFINITELY;
781 } else {
782 state = get_thread_state_base(thread_oop, jt);
783 }
784 return state;
785 }
786
787 jint
788 JvmtiEnvBase::get_vthread_state(oop thread_oop, JavaThread* java_thread) {
789 jint state = 0;
790 bool ext_suspended = JvmtiVTSuspender::is_vthread_suspended(thread_oop);
791 jint interrupted = java_lang_Thread::interrupted(thread_oop);
792
793 if (java_thread != nullptr) {
794 // If virtual thread is blocked on a monitor enter the BLOCKED_ON_MONITOR_ENTER bit
795 // is set for carrier thread instead of virtual.
796 // Other state bits except filtered ones are expected to be the same.
797 oop ct_oop = java_lang_VirtualThread::carrier_thread(thread_oop);
798 jint filtered_bits = JVMTI_THREAD_STATE_SUSPENDED | JVMTI_THREAD_STATE_INTERRUPTED;
799
800 // This call can trigger a safepoint, so thread_oop must not be used after it.
801 state = get_thread_state_base(ct_oop, java_thread) & ~filtered_bits;
802 } else {
803 int vt_state = java_lang_VirtualThread::state(thread_oop);
804 state = (jint)java_lang_VirtualThread::map_state_to_thread_status(vt_state);
805 }
806 // Ensure the thread has not exited after retrieving suspended/interrupted values.
807 if ((state & JVMTI_THREAD_STATE_ALIVE) != 0) {
808 if (ext_suspended) {
809 state |= JVMTI_THREAD_STATE_SUSPENDED;
810 }
811 if (interrupted) {
812 state |= JVMTI_THREAD_STATE_INTERRUPTED;
813 }
814 }
815 return state;
816 }
817
818 jint
819 JvmtiEnvBase::get_thread_or_vthread_state(oop thread_oop, JavaThread* java_thread) {
820 jint state = 0;
821 if (java_lang_VirtualThread::is_instance(thread_oop)) {
822 state = JvmtiEnvBase::get_vthread_state(thread_oop, java_thread);
823 } else {
824 state = JvmtiEnvBase::get_thread_state(thread_oop, java_thread);
825 }
826 return state;
827 }
828
829 jvmtiError
830 JvmtiEnvBase::get_live_threads(JavaThread* current_thread, Handle group_hdl, jint *count_ptr, Handle **thread_objs_p) {
831 jint count = 0;
832 Handle *thread_objs = nullptr;
833 ThreadsListEnumerator tle(current_thread, /* include_jvmti_agent_threads */ true);
834 int nthreads = tle.num_threads();
835 if (nthreads > 0) {
836 thread_objs = NEW_RESOURCE_ARRAY_RETURN_NULL(Handle, nthreads);
837 NULL_CHECK(thread_objs, JVMTI_ERROR_OUT_OF_MEMORY);
838 for (int i = 0; i < nthreads; i++) {
839 Handle thread = tle.get_threadObj(i);
840 if (thread()->is_a(vmClasses::Thread_klass()) && java_lang_Thread::threadGroup(thread()) == group_hdl()) {
841 thread_objs[count++] = thread;
842 }
843 }
844 }
845 *thread_objs_p = thread_objs;
846 *count_ptr = count;
847 return JVMTI_ERROR_NONE;
848 }
849
850 jvmtiError
851 JvmtiEnvBase::get_subgroups(JavaThread* current_thread, Handle group_hdl, jint *count_ptr, objArrayHandle *group_objs_p) {
852
853 // This call collects the strong and weak groups
854 JavaThread* THREAD = current_thread;
855 JavaValue result(T_OBJECT);
856 JavaCalls::call_virtual(&result,
857 group_hdl,
858 vmClasses::ThreadGroup_klass(),
859 SymbolTable::new_permanent_symbol("subgroupsAsArray"),
860 vmSymbols::void_threadgroup_array_signature(),
861 THREAD);
862 if (HAS_PENDING_EXCEPTION) {
863 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
864 CLEAR_PENDING_EXCEPTION;
865 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
866 return JVMTI_ERROR_OUT_OF_MEMORY;
867 } else {
868 return JVMTI_ERROR_INTERNAL;
869 }
870 }
871
872 assert(result.get_type() == T_OBJECT, "just checking");
873 objArrayOop groups = (objArrayOop)result.get_oop();
874
875 *count_ptr = groups == nullptr ? 0 : groups->length();
876 *group_objs_p = objArrayHandle(current_thread, groups);
877
878 return JVMTI_ERROR_NONE;
879 }
880
881 //
882 // Object Monitor Information
883 //
884
885 //
886 // Count the number of objects for a lightweight monitor. The hobj
887 // parameter is object that owns the monitor so this routine will
888 // count the number of times the same object was locked by frames
889 // in java_thread.
890 //
891 jint
892 JvmtiEnvBase::count_locked_objects(JavaThread *java_thread, Handle hobj) {
893 jint ret = 0;
894 if (!java_thread->has_last_Java_frame()) {
895 return ret; // no Java frames so no monitors
896 }
897
898 Thread* current_thread = Thread::current();
899 ResourceMark rm(current_thread);
900 HandleMark hm(current_thread);
901 RegisterMap reg_map(java_thread,
902 RegisterMap::UpdateMap::include,
903 RegisterMap::ProcessFrames::include,
904 RegisterMap::WalkContinuation::skip);
905
906 for (javaVFrame *jvf = java_thread->last_java_vframe(®_map); jvf != nullptr;
907 jvf = jvf->java_sender()) {
908 GrowableArray<MonitorInfo*>* mons = jvf->monitors();
909 if (!mons->is_empty()) {
910 for (int i = 0; i < mons->length(); i++) {
911 MonitorInfo *mi = mons->at(i);
912 if (mi->owner_is_scalar_replaced()) continue;
913
914 // see if owner of the monitor is our object
915 if (mi->owner() != nullptr && mi->owner() == hobj()) {
916 ret++;
917 }
918 }
919 }
920 }
921 return ret;
922 }
923
924 jvmtiError
925 JvmtiEnvBase::get_current_contended_monitor(JavaThread *calling_thread, JavaThread *java_thread,
926 jobject *monitor_ptr, bool is_virtual) {
927 Thread *current_thread = Thread::current();
928 assert(java_thread->is_handshake_safe_for(current_thread),
929 "call by myself or at handshake");
930 if (!is_virtual && JvmtiEnvBase::is_cthread_with_continuation(java_thread)) {
931 // Carrier thread with a mounted continuation case.
932 // No contended monitor can be owned by carrier thread in this case.
933 *monitor_ptr = nullptr;
934 return JVMTI_ERROR_NONE;
935 }
936 oop obj = nullptr;
937 // The ObjectMonitor* can't be async deflated since we are either
938 // at a safepoint or the calling thread is operating on itself so
939 // it cannot leave the underlying wait()/enter() call.
940 ObjectMonitor *mon = java_thread->current_waiting_monitor();
941 if (mon == nullptr) {
942 // thread is not doing an Object.wait() call
943 mon = java_thread->current_pending_monitor();
944 if (mon != nullptr) {
945 // The thread is trying to enter() an ObjectMonitor.
946 obj = mon->object();
947 assert(obj != nullptr, "ObjectMonitor should have a valid object!");
948 }
949 } else {
950 // thread is doing an Object.wait() call
951 oop thread_oop = get_vthread_or_thread_oop(java_thread);
952 jint state = get_thread_or_vthread_state(thread_oop, java_thread);
953
954 if (state & JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER) {
955 // thread is re-entering the monitor in an Object.wait() call
956 obj = mon->object();
957 assert(obj != nullptr, "Object.wait() should have an object");
958 }
959 }
960
961 if (obj == nullptr) {
962 *monitor_ptr = nullptr;
963 } else {
964 HandleMark hm(current_thread);
965 Handle hobj(current_thread, obj);
966 *monitor_ptr = jni_reference(calling_thread, hobj);
967 }
968 return JVMTI_ERROR_NONE;
969 }
970
971 jvmtiError
972 JvmtiEnvBase::get_owned_monitors(JavaThread *calling_thread, JavaThread* java_thread,
973 GrowableArray<jvmtiMonitorStackDepthInfo*> *owned_monitors_list) {
974 // Note:
975 // calling_thread is the thread that requested the list of monitors for java_thread.
976 // java_thread is the thread owning the monitors.
977 // current_thread is the thread executing this code, can be a non-JavaThread (e.g. VM Thread).
978 // And they all may be different threads.
979 jvmtiError err = JVMTI_ERROR_NONE;
980 Thread *current_thread = Thread::current();
981 assert(java_thread->is_handshake_safe_for(current_thread),
982 "call by myself or at handshake");
983
984 if (JvmtiEnvBase::is_cthread_with_continuation(java_thread)) {
985 // Carrier thread with a mounted continuation case.
986 // No contended monitor can be owned by carrier thread in this case.
987 return JVMTI_ERROR_NONE;
988 }
989 if (java_thread->has_last_Java_frame()) {
990 ResourceMark rm(current_thread);
991 HandleMark hm(current_thread);
992 RegisterMap reg_map(java_thread,
993 RegisterMap::UpdateMap::include,
994 RegisterMap::ProcessFrames::include,
995 RegisterMap::WalkContinuation::skip);
996
997 int depth = 0;
998 for (javaVFrame *jvf = get_cthread_last_java_vframe(java_thread, ®_map);
999 jvf != nullptr; jvf = jvf->java_sender()) {
1000 if (MaxJavaStackTraceDepth == 0 || depth++ < MaxJavaStackTraceDepth) { // check for stack too deep
1001 // add locked objects for this frame into list
1002 err = get_locked_objects_in_frame(calling_thread, java_thread, jvf, owned_monitors_list, depth-1);
1003 if (err != JVMTI_ERROR_NONE) {
1004 return err;
1005 }
1006 }
1007 }
1008 }
1009
1010 // Get off stack monitors. (e.g. acquired via jni MonitorEnter).
1011 JvmtiMonitorClosure jmc(calling_thread, owned_monitors_list, this);
1012 ObjectSynchronizer::owned_monitors_iterate(&jmc, java_thread);
1013 err = jmc.error();
1014
1015 return err;
1016 }
1017
1018 jvmtiError
1019 JvmtiEnvBase::get_owned_monitors(JavaThread* calling_thread, JavaThread* carrier, javaVFrame* jvf,
1020 GrowableArray<jvmtiMonitorStackDepthInfo*> *owned_monitors_list, oop vthread) {
1021 jvmtiError err = JVMTI_ERROR_NONE;
1022 Thread *current_thread = Thread::current();
1023 assert(carrier == nullptr || carrier->is_handshake_safe_for(current_thread),
1024 "call by myself or at handshake");
1025
1026 int depth = 0;
1027 for ( ; jvf != nullptr; jvf = jvf->java_sender()) {
1028 if (MaxJavaStackTraceDepth == 0 || depth++ < MaxJavaStackTraceDepth) { // check for stack too deep
1029 // Add locked objects for this frame into list.
1030 err = get_locked_objects_in_frame(calling_thread, carrier, jvf, owned_monitors_list, depth - 1, vthread);
1031 if (err != JVMTI_ERROR_NONE) {
1032 return err;
1033 }
1034 }
1035 }
1036
1037 // Get off stack monitors. (e.g. acquired via jni MonitorEnter).
1038 JvmtiMonitorClosure jmc(calling_thread, owned_monitors_list, this);
1039 ObjectSynchronizer::owned_monitors_iterate(&jmc, carrier != nullptr ? carrier->threadObj() : vthread);
1040 err = jmc.error();
1041
1042 return err;
1043 }
1044
1045 // Save JNI local handles for any objects that this frame owns.
1046 jvmtiError
1047 JvmtiEnvBase::get_locked_objects_in_frame(JavaThread* calling_thread, JavaThread* target,
1048 javaVFrame *jvf, GrowableArray<jvmtiMonitorStackDepthInfo*>* owned_monitors_list,
1049 jint stack_depth, oop vthread) {
1050 jvmtiError err = JVMTI_ERROR_NONE;
1051 Thread* current_thread = Thread::current();
1052 ResourceMark rm(current_thread);
1053 HandleMark hm(current_thread);
1054
1055 GrowableArray<MonitorInfo*>* mons = jvf->monitors();
1056 if (mons->is_empty()) {
1057 return err; // this javaVFrame holds no monitors
1058 }
1059
1060 oop wait_obj = nullptr;
1061 {
1062 // The ObjectMonitor* can't be async deflated since we are either
1063 // at a safepoint or the calling thread is operating on itself so
1064 // it cannot leave the underlying wait() call.
1065 // Save object of current wait() call (if any) for later comparison.
1066 if (target != nullptr) {
1067 ObjectMonitor *mon = target->current_waiting_monitor();
1068 if (mon != nullptr) wait_obj = mon->object();
1069 }
1070 }
1071 oop pending_obj = nullptr;
1072 {
1073 // The ObjectMonitor* can't be async deflated since we are either
1074 // at a safepoint or the calling thread is operating on itself so
1075 // it cannot leave the underlying enter() call.
1076 // Save object of current enter() call (if any) for later comparison.
1077 if (target != nullptr) {
1078 ObjectMonitor *mon = target->current_pending_monitor();
1079 if (mon != nullptr) pending_obj = mon->object();
1080 } else {
1081 assert(vthread != nullptr, "no vthread oop");
1082 oop oopCont = java_lang_VirtualThread::continuation(vthread);
1083 assert(oopCont != nullptr, "vthread with no continuation");
1084 stackChunkOop chunk = jdk_internal_vm_Continuation::tail(oopCont);
1085 assert(chunk != nullptr, "unmounted vthread should have a chunk");
1086 ObjectMonitor *mon = chunk->current_pending_monitor();
1087 if (mon != nullptr) pending_obj = mon->object();
1088 }
1089 }
1090
1091 for (int i = 0; i < mons->length(); i++) {
1092 MonitorInfo *mi = mons->at(i);
1093
1094 if (mi->owner_is_scalar_replaced()) continue;
1095
1096 oop obj = mi->owner();
1097 if (obj == nullptr) {
1098 // this monitor doesn't have an owning object so skip it
1099 continue;
1100 }
1101
1102 if (wait_obj == obj) {
1103 // the thread is waiting on this monitor so it isn't really owned
1104 continue;
1105 }
1106
1107 if (pending_obj == obj) {
1108 // the thread is pending on this monitor so it isn't really owned
1109 continue;
1110 }
1111
1112 if (owned_monitors_list->length() > 0) {
1113 // Our list has at least one object on it so we have to check
1114 // for recursive object locking
1115 bool found = false;
1116 for (int j = 0; j < owned_monitors_list->length(); j++) {
1117 jobject jobj = ((jvmtiMonitorStackDepthInfo*)owned_monitors_list->at(j))->monitor;
1118 oop check = JNIHandles::resolve(jobj);
1119 if (check == obj) {
1120 found = true; // we found the object
1121 break;
1122 }
1123 }
1124
1125 if (found) {
1126 // already have this object so don't include it
1127 continue;
1128 }
1129 }
1130
1131 // add the owning object to our list
1132 jvmtiMonitorStackDepthInfo *jmsdi;
1133 err = allocate(sizeof(jvmtiMonitorStackDepthInfo), (unsigned char **)&jmsdi);
1134 if (err != JVMTI_ERROR_NONE) {
1135 return err;
1136 }
1137 Handle hobj(Thread::current(), obj);
1138 jmsdi->monitor = jni_reference(calling_thread, hobj);
1139 jmsdi->stack_depth = stack_depth;
1140 owned_monitors_list->append(jmsdi);
1141 }
1142
1143 return err;
1144 }
1145
1146 jvmtiError
1147 JvmtiEnvBase::get_stack_trace(javaVFrame *jvf,
1148 jint start_depth, jint max_count,
1149 jvmtiFrameInfo* frame_buffer, jint* count_ptr) {
1150 Thread *current_thread = Thread::current();
1151 ResourceMark rm(current_thread);
1152 HandleMark hm(current_thread);
1153 int count = 0;
1154
1155 if (start_depth != 0) {
1156 if (start_depth > 0) {
1157 for (int j = 0; j < start_depth && jvf != nullptr; j++) {
1158 jvf = jvf->java_sender();
1159 }
1160 if (jvf == nullptr) {
1161 // start_depth is deeper than the stack depth.
1162 return JVMTI_ERROR_ILLEGAL_ARGUMENT;
1163 }
1164 } else { // start_depth < 0
1165 // We are referencing the starting depth based on the oldest
1166 // part of the stack.
1167 // Optimize to limit the number of times that java_sender() is called.
1168 javaVFrame *jvf_cursor = jvf;
1169 javaVFrame *jvf_prev = nullptr;
1170 javaVFrame *jvf_prev_prev = nullptr;
1171 int j = 0;
1172 while (jvf_cursor != nullptr) {
1173 jvf_prev_prev = jvf_prev;
1174 jvf_prev = jvf_cursor;
1175 for (j = 0; j > start_depth && jvf_cursor != nullptr; j--) {
1176 jvf_cursor = jvf_cursor->java_sender();
1177 }
1178 }
1179 if (j == start_depth) {
1180 // Previous pointer is exactly where we want to start.
1181 jvf = jvf_prev;
1182 } else {
1183 // We need to back up further to get to the right place.
1184 if (jvf_prev_prev == nullptr) {
1185 // The -start_depth is greater than the stack depth.
1186 return JVMTI_ERROR_ILLEGAL_ARGUMENT;
1187 }
1188 // j is now the number of frames on the stack starting with
1189 // jvf_prev, we start from jvf_prev_prev and move older on
1190 // the stack that many, and the result is -start_depth frames
1191 // remaining.
1192 jvf = jvf_prev_prev;
1193 for (; j < 0; j++) {
1194 jvf = jvf->java_sender();
1195 }
1196 }
1197 }
1198 }
1199 for (; count < max_count && jvf != nullptr; count++) {
1200 frame_buffer[count].method = jvf->method()->jmethod_id();
1201 frame_buffer[count].location = (jvf->method()->is_native() ? -1 : jvf->bci());
1202 jvf = jvf->java_sender();
1203 }
1204 *count_ptr = count;
1205 return JVMTI_ERROR_NONE;
1206 }
1207
1208 jvmtiError
1209 JvmtiEnvBase::get_stack_trace(JavaThread *java_thread,
1210 jint start_depth, jint max_count,
1211 jvmtiFrameInfo* frame_buffer, jint* count_ptr) {
1212 Thread *current_thread = Thread::current();
1213 assert(SafepointSynchronize::is_at_safepoint() ||
1214 java_thread->is_handshake_safe_for(current_thread),
1215 "call by myself / at safepoint / at handshake");
1216 int count = 0;
1217 jvmtiError err = JVMTI_ERROR_NONE;
1218
1219 if (java_thread->has_last_Java_frame()) {
1220 RegisterMap reg_map(java_thread,
1221 RegisterMap::UpdateMap::include,
1222 RegisterMap::ProcessFrames::skip,
1223 RegisterMap::WalkContinuation::skip);
1224 ResourceMark rm(current_thread);
1225 javaVFrame *jvf = get_cthread_last_java_vframe(java_thread, ®_map);
1226
1227 err = get_stack_trace(jvf, start_depth, max_count, frame_buffer, count_ptr);
1228 } else {
1229 *count_ptr = 0;
1230 if (start_depth != 0) {
1231 // no frames and there is a starting depth
1232 err = JVMTI_ERROR_ILLEGAL_ARGUMENT;
1233 }
1234 }
1235 return err;
1236 }
1237
1238 jint
1239 JvmtiEnvBase::get_frame_count(javaVFrame *jvf) {
1240 int count = 0;
1241
1242 while (jvf != nullptr) {
1243 jvf = jvf->java_sender();
1244 count++;
1245 }
1246 return count;
1247 }
1248
1249 jvmtiError
1250 JvmtiEnvBase::get_frame_count(JavaThread* jt, jint *count_ptr) {
1251 Thread *current_thread = Thread::current();
1252 assert(current_thread == jt ||
1253 SafepointSynchronize::is_at_safepoint() ||
1254 jt->is_handshake_safe_for(current_thread),
1255 "call by myself / at safepoint / at handshake");
1256
1257 if (!jt->has_last_Java_frame()) { // no Java frames
1258 *count_ptr = 0;
1259 } else {
1260 ResourceMark rm(current_thread);
1261 RegisterMap reg_map(jt,
1262 RegisterMap::UpdateMap::include,
1263 RegisterMap::ProcessFrames::include,
1264 RegisterMap::WalkContinuation::skip);
1265 javaVFrame *jvf = get_cthread_last_java_vframe(jt, ®_map);
1266
1267 *count_ptr = get_frame_count(jvf);
1268 }
1269 return JVMTI_ERROR_NONE;
1270 }
1271
1272 jvmtiError
1273 JvmtiEnvBase::get_frame_count(oop vthread_oop, jint *count_ptr) {
1274 Thread *current_thread = Thread::current();
1275 ResourceMark rm(current_thread);
1276 javaVFrame *jvf = JvmtiEnvBase::get_vthread_jvf(vthread_oop);
1277
1278 *count_ptr = get_frame_count(jvf);
1279 return JVMTI_ERROR_NONE;
1280 }
1281
1282 jvmtiError
1283 JvmtiEnvBase::get_frame_location(javaVFrame* jvf, jint depth,
1284 jmethodID* method_ptr, jlocation* location_ptr) {
1285 int cur_depth = 0;
1286
1287 while (jvf != nullptr && cur_depth < depth) {
1288 jvf = jvf->java_sender();
1289 cur_depth++;
1290 }
1291 assert(depth >= cur_depth, "ran out of frames too soon");
1292 if (jvf == nullptr) {
1293 return JVMTI_ERROR_NO_MORE_FRAMES;
1294 }
1295 Method* method = jvf->method();
1296 if (method->is_native()) {
1297 *location_ptr = -1;
1298 } else {
1299 *location_ptr = jvf->bci();
1300 }
1301 *method_ptr = method->jmethod_id();
1302 return JVMTI_ERROR_NONE;
1303 }
1304
1305 jvmtiError
1306 JvmtiEnvBase::get_frame_location(JavaThread *java_thread, jint depth,
1307 jmethodID* method_ptr, jlocation* location_ptr) {
1308 Thread* current = Thread::current();
1309 assert(java_thread->is_handshake_safe_for(current),
1310 "call by myself or at handshake");
1311 if (!java_thread->has_last_Java_frame()) {
1312 return JVMTI_ERROR_NO_MORE_FRAMES;
1313 }
1314 ResourceMark rm(current);
1315 HandleMark hm(current);
1316 RegisterMap reg_map(java_thread,
1317 RegisterMap::UpdateMap::include,
1318 RegisterMap::ProcessFrames::skip,
1319 RegisterMap::WalkContinuation::include);
1320 javaVFrame* jvf = JvmtiEnvBase::get_cthread_last_java_vframe(java_thread, ®_map);
1321
1322 return get_frame_location(jvf, depth, method_ptr, location_ptr);
1323 }
1324
1325 jvmtiError
1326 JvmtiEnvBase::get_frame_location(oop vthread_oop, jint depth,
1327 jmethodID* method_ptr, jlocation* location_ptr) {
1328 Thread* current = Thread::current();
1329 ResourceMark rm(current);
1330 HandleMark hm(current);
1331 javaVFrame *jvf = JvmtiEnvBase::get_vthread_jvf(vthread_oop);
1332
1333 return get_frame_location(jvf, depth, method_ptr, location_ptr);
1334 }
1335
1336 jvmtiError
1337 JvmtiEnvBase::set_frame_pop(JvmtiThreadState* state, javaVFrame* jvf, jint depth) {
1338 for (int d = 0; jvf != nullptr && d < depth; d++) {
1339 jvf = jvf->java_sender();
1340 }
1341 if (jvf == nullptr) {
1342 return JVMTI_ERROR_NO_MORE_FRAMES;
1343 }
1344 if (jvf->method()->is_native()) {
1345 return JVMTI_ERROR_OPAQUE_FRAME;
1346 }
1347 assert(jvf->frame_pointer() != nullptr, "frame pointer mustn't be null");
1348 int frame_number = (int)get_frame_count(jvf);
1349 state->env_thread_state((JvmtiEnvBase*)this)->set_frame_pop(frame_number);
1350 return JVMTI_ERROR_NONE;
1351 }
1352
1353 bool
1354 JvmtiEnvBase::is_cthread_with_mounted_vthread(JavaThread* jt) {
1355 oop thread_oop = jt->threadObj();
1356 assert(thread_oop != nullptr, "sanity check");
1357 oop mounted_vt = jt->jvmti_vthread();
1358
1359 return mounted_vt != nullptr && mounted_vt != thread_oop;
1360 }
1361
1362 bool
1363 JvmtiEnvBase::is_cthread_with_continuation(JavaThread* jt) {
1364 const ContinuationEntry* cont_entry = nullptr;
1365 if (jt->has_last_Java_frame()) {
1366 cont_entry = jt->vthread_continuation();
1367 }
1368 return cont_entry != nullptr && is_cthread_with_mounted_vthread(jt);
1369 }
1370
1371 // Check if VirtualThread or BoundVirtualThread is suspended.
1372 bool
1373 JvmtiEnvBase::is_vthread_suspended(oop vt_oop, JavaThread* jt) {
1374 bool suspended = false;
1375 if (java_lang_VirtualThread::is_instance(vt_oop)) {
1376 suspended = JvmtiVTSuspender::is_vthread_suspended(vt_oop);
1377 }
1378 if (vt_oop->is_a(vmClasses::BoundVirtualThread_klass())) {
1379 suspended = jt->is_suspended();
1380 }
1381 return suspended;
1382 }
1383
1384 // If (thread == null) then return current thread object.
1385 // Otherwise return JNIHandles::resolve_external_guard(thread).
1386 oop
1387 JvmtiEnvBase::current_thread_obj_or_resolve_external_guard(jthread thread) {
1388 oop thread_obj = JNIHandles::resolve_external_guard(thread);
1389 if (thread == nullptr) {
1390 thread_obj = get_vthread_or_thread_oop(JavaThread::current());
1391 }
1392 return thread_obj;
1393 }
1394
1395 jvmtiError
1396 JvmtiEnvBase::get_threadOop_and_JavaThread(ThreadsList* t_list, jthread thread, JavaThread* cur_thread,
1397 JavaThread** jt_pp, oop* thread_oop_p) {
1398 JavaThread* java_thread = nullptr;
1399 oop thread_oop = nullptr;
1400
1401 if (thread == nullptr) {
1402 if (cur_thread == nullptr) { // cur_thread can be null when called from a VM_op
1403 return JVMTI_ERROR_INVALID_THREAD;
1404 }
1405 java_thread = cur_thread;
1406 thread_oop = get_vthread_or_thread_oop(java_thread);
1407 if (thread_oop == nullptr || !thread_oop->is_a(vmClasses::Thread_klass())) {
1408 return JVMTI_ERROR_INVALID_THREAD;
1409 }
1410 } else {
1411 jvmtiError err = JvmtiExport::cv_external_thread_to_JavaThread(t_list, thread, &java_thread, &thread_oop);
1412 if (err != JVMTI_ERROR_NONE) {
1413 // We got an error code so we don't have a JavaThread*, but only return
1414 // an error from here if we didn't get a valid thread_oop. In a vthread case
1415 // the cv_external_thread_to_JavaThread is expected to correctly set the
1416 // thread_oop and return JVMTI_ERROR_INVALID_THREAD which we ignore here.
1417 if (thread_oop == nullptr || err != JVMTI_ERROR_INVALID_THREAD) {
1418 *thread_oop_p = thread_oop;
1419 return err;
1420 }
1421 }
1422 if (java_thread == nullptr && java_lang_VirtualThread::is_instance(thread_oop)) {
1423 java_thread = get_JavaThread_or_null(thread_oop);
1424 }
1425 }
1426 *jt_pp = java_thread;
1427 *thread_oop_p = thread_oop;
1428 if (java_lang_VirtualThread::is_instance(thread_oop) &&
1429 !JvmtiEnvBase::is_vthread_alive(thread_oop)) {
1430 return JVMTI_ERROR_THREAD_NOT_ALIVE;
1431 }
1432 return JVMTI_ERROR_NONE;
1433 }
1434
1435 // Check for JVMTI_ERROR_NOT_SUSPENDED and JVMTI_ERROR_OPAQUE_FRAME errors.
1436 // Used in PopFrame and ForceEarlyReturn implementations.
1437 jvmtiError
1438 JvmtiEnvBase::check_non_suspended_or_opaque_frame(JavaThread* jt, oop thr_obj, bool self) {
1439 bool is_virtual = thr_obj != nullptr && thr_obj->is_a(vmClasses::BaseVirtualThread_klass());
1440
1441 if (is_virtual) {
1442 if (!is_JavaThread_current(jt, thr_obj)) {
1443 if (!is_vthread_suspended(thr_obj, jt)) {
1444 return JVMTI_ERROR_THREAD_NOT_SUSPENDED;
1445 }
1446 if (jt == nullptr) { // unmounted virtual thread
1447 return JVMTI_ERROR_OPAQUE_FRAME;
1448 }
1449 }
1450 } else { // platform thread
1451 if (!self && !jt->is_suspended() &&
1452 !jt->is_carrier_thread_suspended()) {
1453 return JVMTI_ERROR_THREAD_NOT_SUSPENDED;
1454 }
1455 }
1456 return JVMTI_ERROR_NONE;
1457 }
1458
1459 jvmtiError
1460 JvmtiEnvBase::get_object_monitor_usage(JavaThread* calling_thread, jobject object, jvmtiMonitorUsage* info_ptr) {
1461 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
1462 Thread* current_thread = VMThread::vm_thread();
1463 assert(current_thread == Thread::current(), "must be");
1464
1465 HandleMark hm(current_thread);
1466 Handle hobj;
1467
1468 // Check arguments
1469 {
1470 oop mirror = JNIHandles::resolve_external_guard(object);
1471 NULL_CHECK(mirror, JVMTI_ERROR_INVALID_OBJECT);
1472 NULL_CHECK(info_ptr, JVMTI_ERROR_NULL_POINTER);
1473
1474 hobj = Handle(current_thread, mirror);
1475 }
1476
1477 ThreadsListHandle tlh(current_thread);
1478 JavaThread *owning_thread = nullptr;
1479 jvmtiMonitorUsage ret = {
1480 nullptr, 0, 0, nullptr, 0, nullptr
1481 };
1482
1483 uint32_t debug_bits = 0;
1484 // first derive the object's owner and entry_count (if any)
1485 owning_thread = ObjectSynchronizer::get_lock_owner(tlh.list(), hobj);
1486 if (owning_thread != nullptr) {
1487 oop thread_oop = get_vthread_or_thread_oop(owning_thread);
1488 bool is_virtual = thread_oop->is_a(vmClasses::BaseVirtualThread_klass());
1489 if (is_virtual) {
1490 thread_oop = nullptr;
1491 }
1492 Handle th(current_thread, thread_oop);
1493 ret.owner = (jthread)jni_reference(calling_thread, th);
1494
1495 // The recursions field of a monitor does not reflect recursions
1496 // as lightweight locks before inflating the monitor are not included.
1497 // We have to count the number of recursive monitor entries the hard way.
1498 // We pass a handle to survive any GCs along the way.
1499 ret.entry_count = is_virtual ? 0 : count_locked_objects(owning_thread, hobj);
1500 }
1501 // implied else: entry_count == 0
1502
1503 jint nWant = 0, nWait = 0;
1504 markWord mark = hobj->mark();
1505 ResourceMark rm(current_thread);
1506 GrowableArray<JavaThread*>* wantList = nullptr;
1507
1508 ObjectMonitor* mon = mark.has_monitor()
1509 ? ObjectSynchronizer::read_monitor(current_thread, hobj(), mark)
1510 : nullptr;
1511
1512 if (mon != nullptr) {
1513 // this object has a heavyweight monitor
1514 nWant = mon->contentions(); // # of threads contending for monitor entry, but not re-entry
1515 nWait = mon->waiters(); // # of threads waiting for notification,
1516 // or to re-enter monitor, in Object.wait()
1517
1518 // Get the actual set of threads trying to enter, or re-enter, the monitor.
1519 wantList = Threads::get_pending_threads(tlh.list(), nWant + nWait, (address)mon);
1520 nWant = wantList->length();
1521 } else {
1522 // this object has a lightweight monitor
1523 }
1524
1525 jint skipped = 0;
1526 if (mon != nullptr) {
1527 // Robustness: the actual waiting list can be smaller.
1528 // The nWait count we got from the mon->waiters() may include the re-entering
1529 // the monitor threads after being notified. Here we are correcting the actual
1530 // number of the waiting threads by excluding those re-entering the monitor.
1531 nWait = 0;
1532 for (ObjectWaiter* waiter = mon->first_waiter();
1533 waiter != nullptr && (nWait == 0 || waiter != mon->first_waiter());
1534 waiter = mon->next_waiter(waiter)) {
1535 JavaThread *w = mon->thread_of_waiter(waiter);
1536 if (w == nullptr) {
1537 skipped++;
1538 } else {
1539 oop thread_oop = get_vthread_or_thread_oop(w);
1540 if (thread_oop->is_a(vmClasses::BaseVirtualThread_klass())) {
1541 skipped++;
1542 }
1543 }
1544 nWait++;
1545 }
1546 }
1547 ret.waiter_count = nWant;
1548 ret.notify_waiter_count = nWait - skipped;
1549
1550 // Allocate memory for heavyweight and lightweight monitor.
1551 jvmtiError err;
1552 err = allocate(ret.waiter_count * sizeof(jthread *), (unsigned char**)&ret.waiters);
1553 if (err != JVMTI_ERROR_NONE) {
1554 return err;
1555 }
1556 err = allocate(ret.notify_waiter_count * sizeof(jthread *),
1557 (unsigned char**)&ret.notify_waiters);
1558 if (err != JVMTI_ERROR_NONE) {
1559 deallocate((unsigned char*)ret.waiters);
1560 return err;
1561 }
1562
1563 // now derive the rest of the fields
1564 if (mon != nullptr) {
1565 // this object has a heavyweight monitor
1566
1567 // null out memory for robustness
1568 if (ret.waiters != nullptr) {
1569 memset(ret.waiters, 0, ret.waiter_count * sizeof(jthread *));
1570 }
1571 if (ret.notify_waiters != nullptr) {
1572 memset(ret.notify_waiters, 0, ret.notify_waiter_count * sizeof(jthread *));
1573 }
1574
1575 if (ret.waiter_count > 0) { // we have contending threads waiting to enter/re-enter the monitor
1576 // identify threads waiting to enter and re-enter the monitor
1577 // get_pending_threads returns only java thread so we do not need to
1578 // check for non java threads.
1579 for (int i = 0; i < nWant; i++) {
1580 JavaThread *pending_thread = wantList->at(i);
1581 Handle th(current_thread, get_vthread_or_thread_oop(pending_thread));
1582 ret.waiters[i] = (jthread)jni_reference(calling_thread, th);
1583 }
1584 }
1585 if (ret.notify_waiter_count > 0) { // we have threads waiting to be notified in Object.wait()
1586 ObjectWaiter *waiter = mon->first_waiter();
1587 jint skipped = 0;
1588 for (int i = 0; i < nWait; i++) {
1589 JavaThread *w = mon->thread_of_waiter(waiter);
1590 bool is_virtual;
1591 if (w == nullptr) {
1592 is_virtual = true;
1593 } else {
1594 oop thread_oop = get_vthread_or_thread_oop(w);
1595 is_virtual = thread_oop->is_a(vmClasses::BaseVirtualThread_klass());
1596 }
1597 if (is_virtual) {
1598 skipped++;
1599 } else {
1600 // If the thread was found on the ObjectWaiter list, then
1601 // it has not been notified.
1602 Handle th(current_thread, w->threadObj());
1603 ret.notify_waiters[i - skipped] = (jthread)jni_reference(calling_thread, th);
1604 }
1605 waiter = mon->next_waiter(waiter);
1606 }
1607 }
1608 } else {
1609 // this object has a lightweight monitor and we have nothing more
1610 // to do here because the defaults are just fine.
1611 }
1612
1613 // we don't update return parameter unless everything worked
1614 *info_ptr = ret;
1615
1616 return JVMTI_ERROR_NONE;
1617 }
1618
1619 jvmtiError
1620 JvmtiEnvBase::check_thread_list(jint count, const jthread* list) {
1621 if (list == nullptr && count != 0) {
1622 return JVMTI_ERROR_NULL_POINTER;
1623 }
1624 for (int i = 0; i < count; i++) {
1625 jthread thread = list[i];
1626 oop thread_oop = JNIHandles::resolve_external_guard(thread);
1627 if (thread_oop == nullptr || !thread_oop->is_a(vmClasses::BaseVirtualThread_klass())) {
1628 return JVMTI_ERROR_INVALID_THREAD;
1629 }
1630 }
1631 return JVMTI_ERROR_NONE;
1632 }
1633
1634 bool
1635 JvmtiEnvBase::is_in_thread_list(jint count, const jthread* list, oop jt_oop) {
1636 for (int idx = 0; idx < count; idx++) {
1637 jthread thread = list[idx];
1638 oop thread_oop = JNIHandles::resolve_external_guard(thread);
1639 if (thread_oop == jt_oop) {
1640 return true;
1641 }
1642 }
1643 return false;
1644 }
1645
1646 class VM_SetNotifyJvmtiEventsMode : public VM_Operation {
1647 private:
1648 bool _enable;
1649
1650 static void correct_jvmti_thread_state(JavaThread* jt) {
1651 oop ct_oop = jt->threadObj();
1652 oop vt_oop = jt->vthread();
1653 JvmtiThreadState* jt_state = jt->jvmti_thread_state();
1654 JvmtiThreadState* ct_state = java_lang_Thread::jvmti_thread_state(jt->threadObj());
1655 JvmtiThreadState* vt_state = vt_oop != nullptr ? java_lang_Thread::jvmti_thread_state(vt_oop) : nullptr;
1656 bool virt = vt_oop != nullptr && java_lang_VirtualThread::is_instance(vt_oop);
1657
1658 // Correct jt->jvmti_thread_state() and jt->jvmti_vthread().
1659 // It was not maintained while notifyJvmti was disabled.
1660 if (virt) {
1661 jt->set_jvmti_thread_state(nullptr); // reset jt->jvmti_thread_state()
1662 jt->set_jvmti_vthread(vt_oop); // restore jt->jvmti_vthread()
1663 } else {
1664 jt->set_jvmti_thread_state(ct_state); // restore jt->jvmti_thread_state()
1665 jt->set_jvmti_vthread(ct_oop); // restore jt->jvmti_vthread()
1666 }
1667 }
1668
1669 // This function is called only if _enable == true.
1670 // Iterates over all JavaThread's, restores jt->jvmti_thread_state() and
1671 // jt->jvmti_vthread() for VTMS transition protocol.
1672 void correct_jvmti_thread_states() {
1673 for (JavaThread* jt : ThreadsListHandle()) {
1674 if (jt->is_in_VTMS_transition()) {
1675 jt->set_VTMS_transition_mark(true);
1676 continue; // no need in JvmtiThreadState correction below if in transition
1677 }
1678 correct_jvmti_thread_state(jt);
1679 }
1680 }
1681
1682 public:
1683 VMOp_Type type() const { return VMOp_SetNotifyJvmtiEventsMode; }
1684 bool allow_nested_vm_operations() const { return false; }
1685 VM_SetNotifyJvmtiEventsMode(bool enable) : _enable(enable) {
1686 }
1687
1688 void doit() {
1689 if (_enable) {
1690 correct_jvmti_thread_states();
1691 }
1692 JvmtiVTMSTransitionDisabler::set_VTMS_notify_jvmti_events(_enable);
1693 }
1694 };
1695
1696 // This function is to support agents loaded into running VM.
1697 // Must be called in thread-in-native mode.
1698 bool
1699 JvmtiEnvBase::enable_virtual_threads_notify_jvmti() {
1700 if (!Continuations::enabled()) {
1701 return false;
1702 }
1703 if (JvmtiVTMSTransitionDisabler::VTMS_notify_jvmti_events()) {
1704 return false; // already enabled
1705 }
1706 VM_SetNotifyJvmtiEventsMode op(true);
1707 VMThread::execute(&op);
1708 return true;
1709 }
1710
1711 // This function is used in WhiteBox, only needed to test the function above.
1712 // It is unsafe to use this function when virtual threads are executed.
1713 // Must be called in thread-in-native mode.
1714 bool
1715 JvmtiEnvBase::disable_virtual_threads_notify_jvmti() {
1716 if (!Continuations::enabled()) {
1717 return false;
1718 }
1719 if (!JvmtiVTMSTransitionDisabler::VTMS_notify_jvmti_events()) {
1720 return false; // already disabled
1721 }
1722 JvmtiVTMSTransitionDisabler disabler(true); // ensure there are no other disablers
1723 VM_SetNotifyJvmtiEventsMode op(false);
1724 VMThread::execute(&op);
1725 return true;
1726 }
1727
1728 // java_thread - protected by ThreadsListHandle
1729 jvmtiError
1730 JvmtiEnvBase::suspend_thread(oop thread_oop, JavaThread* java_thread, bool single_suspend,
1731 int* need_safepoint_p) {
1732 JavaThread* current = JavaThread::current();
1733 HandleMark hm(current);
1734 Handle thread_h(current, thread_oop);
1735 bool is_virtual = java_lang_VirtualThread::is_instance(thread_h());
1736
1737 if (is_virtual) {
1738 if (single_suspend) {
1739 if (JvmtiVTSuspender::is_vthread_suspended(thread_h())) {
1740 return JVMTI_ERROR_THREAD_SUSPENDED;
1741 }
1742 JvmtiVTSuspender::register_vthread_suspend(thread_h());
1743 // Check if virtual thread is mounted and there is a java_thread.
1744 // A non-null java_thread is always passed in the !single_suspend case.
1745 oop carrier_thread = java_lang_VirtualThread::carrier_thread(thread_h());
1746 java_thread = carrier_thread == nullptr ? nullptr : java_lang_Thread::thread(carrier_thread);
1747 }
1748 // The java_thread can be still blocked in VTMS transition after a previous JVMTI resume call.
1749 // There is no need to suspend the java_thread in this case. After vthread unblocking,
1750 // it will check for ext_suspend request and suspend itself if necessary.
1751 if (java_thread == nullptr || java_thread->is_suspended()) {
1752 // We are done if the virtual thread is unmounted or
1753 // the java_thread is externally suspended.
1754 return JVMTI_ERROR_NONE;
1755 }
1756 // The virtual thread is mounted: suspend the java_thread.
1757 }
1758 // Don't allow hidden thread suspend request.
1759 if (java_thread->is_hidden_from_external_view()) {
1760 return JVMTI_ERROR_NONE;
1761 }
1762 bool is_thread_carrying = is_thread_carrying_vthread(java_thread, thread_h());
1763
1764 // A case of non-virtual thread.
1765 if (!is_virtual) {
1766 // Thread.suspend() is used in some tests. It sets jt->is_suspended() only.
1767 if (java_thread->is_carrier_thread_suspended() ||
1768 (!is_thread_carrying && java_thread->is_suspended())) {
1769 return JVMTI_ERROR_THREAD_SUSPENDED;
1770 }
1771 java_thread->set_carrier_thread_suspended();
1772 }
1773 assert(!java_thread->is_in_VTMS_transition(), "sanity check");
1774
1775 assert(!single_suspend || (!is_virtual && java_thread->is_carrier_thread_suspended()) ||
1776 (is_virtual && JvmtiVTSuspender::is_vthread_suspended(thread_h())),
1777 "sanity check");
1778
1779 // An attempt to handshake-suspend a thread carrying a virtual thread will result in
1780 // suspension of mounted virtual thread. So, we just mark it as suspended
1781 // and it will be actually suspended at virtual thread unmount transition.
1782 if (!is_thread_carrying) {
1783 assert(thread_h() != nullptr, "sanity check");
1784 assert(single_suspend || thread_h()->is_a(vmClasses::BaseVirtualThread_klass()),
1785 "SuspendAllVirtualThreads should never suspend non-virtual threads");
1786 // Case of mounted virtual or attached carrier thread.
1787 if (!JvmtiSuspendControl::suspend(java_thread)) {
1788 // Thread is already suspended or in process of exiting.
1789 if (java_thread->is_exiting()) {
1790 // The thread was in the process of exiting.
1791 return JVMTI_ERROR_THREAD_NOT_ALIVE;
1792 }
1793 return JVMTI_ERROR_THREAD_SUSPENDED;
1794 }
1795 }
1796 return JVMTI_ERROR_NONE;
1797 }
1798
1799 // java_thread - protected by ThreadsListHandle
1800 jvmtiError
1801 JvmtiEnvBase::resume_thread(oop thread_oop, JavaThread* java_thread, bool single_resume) {
1802 JavaThread* current = JavaThread::current();
1803 HandleMark hm(current);
1804 Handle thread_h(current, thread_oop);
1805 bool is_virtual = java_lang_VirtualThread::is_instance(thread_h());
1806
1807 if (is_virtual) {
1808 if (single_resume) {
1809 if (!JvmtiVTSuspender::is_vthread_suspended(thread_h())) {
1810 return JVMTI_ERROR_THREAD_NOT_SUSPENDED;
1811 }
1812 JvmtiVTSuspender::register_vthread_resume(thread_h());
1813 // Check if virtual thread is mounted and there is a java_thread.
1814 // A non-null java_thread is always passed in the !single_resume case.
1815 oop carrier_thread = java_lang_VirtualThread::carrier_thread(thread_h());
1816 java_thread = carrier_thread == nullptr ? nullptr : java_lang_Thread::thread(carrier_thread);
1817 }
1818 // The java_thread can be still blocked in VTMS transition after a previous JVMTI suspend call.
1819 // There is no need to resume the java_thread in this case. After vthread unblocking,
1820 // it will check for is_vthread_suspended request and remain resumed if necessary.
1821 if (java_thread == nullptr || !java_thread->is_suspended()) {
1822 // We are done if the virtual thread is unmounted or
1823 // the java_thread is not externally suspended.
1824 return JVMTI_ERROR_NONE;
1825 }
1826 // The virtual thread is mounted and java_thread is supended: resume the java_thread.
1827 }
1828 // Don't allow hidden thread resume request.
1829 if (java_thread->is_hidden_from_external_view()) {
1830 return JVMTI_ERROR_NONE;
1831 }
1832 bool is_thread_carrying = is_thread_carrying_vthread(java_thread, thread_h());
1833
1834 // A case of a non-virtual thread.
1835 if (!is_virtual) {
1836 if (!java_thread->is_carrier_thread_suspended() &&
1837 (is_thread_carrying || !java_thread->is_suspended())) {
1838 return JVMTI_ERROR_THREAD_NOT_SUSPENDED;
1839 }
1840 java_thread->clear_carrier_thread_suspended();
1841 }
1842 assert(!java_thread->is_in_VTMS_transition(), "sanity check");
1843
1844 if (!is_thread_carrying) {
1845 assert(thread_h() != nullptr, "sanity check");
1846 assert(single_resume || thread_h()->is_a(vmClasses::BaseVirtualThread_klass()),
1847 "ResumeAllVirtualThreads should never resume non-virtual threads");
1848 if (java_thread->is_suspended()) {
1849 if (!JvmtiSuspendControl::resume(java_thread)) {
1850 return JVMTI_ERROR_THREAD_NOT_SUSPENDED;
1851 }
1852 }
1853 }
1854 return JVMTI_ERROR_NONE;
1855 }
1856
1857 ResourceTracker::ResourceTracker(JvmtiEnv* env) {
1858 _env = env;
1859 _allocations = new (mtServiceability) GrowableArray<unsigned char*>(20, mtServiceability);
1860 _failed = false;
1861 }
1862 ResourceTracker::~ResourceTracker() {
1863 if (_failed) {
1864 for (int i=0; i<_allocations->length(); i++) {
1865 _env->deallocate(_allocations->at(i));
1866 }
1867 }
1868 delete _allocations;
1869 }
1870
1871 jvmtiError ResourceTracker::allocate(jlong size, unsigned char** mem_ptr) {
1872 unsigned char *ptr;
1873 jvmtiError err = _env->allocate(size, &ptr);
1874 if (err == JVMTI_ERROR_NONE) {
1875 _allocations->append(ptr);
1876 *mem_ptr = ptr;
1877 } else {
1878 *mem_ptr = nullptr;
1879 _failed = true;
1880 }
1881 return err;
1882 }
1883
1884 unsigned char* ResourceTracker::allocate(jlong size) {
1885 unsigned char* ptr;
1886 allocate(size, &ptr);
1887 return ptr;
1888 }
1889
1890 char* ResourceTracker::strdup(const char* str) {
1891 char *dup_str = (char*)allocate(strlen(str)+1);
1892 if (dup_str != nullptr) {
1893 strcpy(dup_str, str);
1894 }
1895 return dup_str;
1896 }
1897
1898 struct StackInfoNode {
1899 struct StackInfoNode *next;
1900 jvmtiStackInfo info;
1901 };
1902
1903 // Create a jvmtiStackInfo inside a linked list node and create a
1904 // buffer for the frame information, both allocated as resource objects.
1905 // Fill in both the jvmtiStackInfo and the jvmtiFrameInfo.
1906 // Note that either or both of thr and thread_oop
1907 // may be null if the thread is new or has exited.
1908 void
1909 MultipleStackTracesCollector::fill_frames(jthread jt, JavaThread *thr, oop thread_oop) {
1910 #ifdef ASSERT
1911 Thread *current_thread = Thread::current();
1912 assert(SafepointSynchronize::is_at_safepoint() ||
1913 thr == nullptr ||
1914 thr->is_handshake_safe_for(current_thread),
1915 "unmounted virtual thread / call by myself / at safepoint / at handshake");
1916 #endif
1917
1918 jint state = 0;
1919 struct StackInfoNode *node = NEW_RESOURCE_OBJ(struct StackInfoNode);
1920 jvmtiStackInfo *infop = &(node->info);
1921
1922 node->next = head();
1923 set_head(node);
1924 infop->frame_count = 0;
1925 infop->frame_buffer = nullptr;
1926 infop->thread = jt;
1927
1928 if (java_lang_VirtualThread::is_instance(thread_oop)) {
1929 state = JvmtiEnvBase::get_vthread_state(thread_oop, thr);
1930
1931 if ((state & JVMTI_THREAD_STATE_ALIVE) != 0) {
1932 javaVFrame *jvf = JvmtiEnvBase::get_vthread_jvf(thread_oop);
1933 infop->frame_buffer = NEW_RESOURCE_ARRAY(jvmtiFrameInfo, max_frame_count());
1934 _result = env()->get_stack_trace(jvf, 0, max_frame_count(),
1935 infop->frame_buffer, &(infop->frame_count));
1936 }
1937 } else {
1938 state = JvmtiEnvBase::get_thread_state(thread_oop, thr);
1939 if (thr != nullptr && (state & JVMTI_THREAD_STATE_ALIVE) != 0) {
1940 infop->frame_buffer = NEW_RESOURCE_ARRAY(jvmtiFrameInfo, max_frame_count());
1941 _result = env()->get_stack_trace(thr, 0, max_frame_count(),
1942 infop->frame_buffer, &(infop->frame_count));
1943 }
1944 }
1945 _frame_count_total += infop->frame_count;
1946 infop->state = state;
1947 }
1948
1949 // Based on the stack information in the linked list, allocate memory
1950 // block to return and fill it from the info in the linked list.
1951 void
1952 MultipleStackTracesCollector::allocate_and_fill_stacks(jint thread_count) {
1953 // do I need to worry about alignment issues?
1954 jlong alloc_size = thread_count * sizeof(jvmtiStackInfo)
1955 + _frame_count_total * sizeof(jvmtiFrameInfo);
1956 env()->allocate(alloc_size, (unsigned char **)&_stack_info);
1957
1958 // pointers to move through the newly allocated space as it is filled in
1959 jvmtiStackInfo *si = _stack_info + thread_count; // bottom of stack info
1960 jvmtiFrameInfo *fi = (jvmtiFrameInfo *)si; // is the top of frame info
1961
1962 // copy information in resource area into allocated buffer
1963 // insert stack info backwards since linked list is backwards
1964 // insert frame info forwards
1965 // walk the StackInfoNodes
1966 for (struct StackInfoNode *sin = head(); sin != nullptr; sin = sin->next) {
1967 jint frame_count = sin->info.frame_count;
1968 size_t frames_size = frame_count * sizeof(jvmtiFrameInfo);
1969 --si;
1970 memcpy(si, &(sin->info), sizeof(jvmtiStackInfo));
1971 if (frames_size == 0) {
1972 si->frame_buffer = nullptr;
1973 } else {
1974 memcpy(fi, sin->info.frame_buffer, frames_size);
1975 si->frame_buffer = fi; // point to the new allocated copy of the frames
1976 fi += frame_count;
1977 }
1978 }
1979 assert(si == _stack_info, "the last copied stack info must be the first record");
1980 assert((unsigned char *)fi == ((unsigned char *)_stack_info) + alloc_size,
1981 "the last copied frame info must be the last record");
1982 }
1983
1984 // AdapterClosure is to make use of JvmtiUnitedHandshakeClosure objects from
1985 // Handshake::execute() which is unaware of the do_vthread() member functions.
1986 class AdapterClosure : public HandshakeClosure {
1987 JvmtiUnitedHandshakeClosure* _hs_cl;
1988 Handle _target_h;
1989
1990 public:
1991 AdapterClosure(JvmtiUnitedHandshakeClosure* hs_cl, Handle target_h)
1992 : HandshakeClosure(hs_cl->name()), _hs_cl(hs_cl), _target_h(target_h) {}
1993
1994 virtual void do_thread(Thread* target) {
1995 if (java_lang_VirtualThread::is_instance(_target_h())) {
1996 _hs_cl->do_vthread(_target_h); // virtual thread
1997 } else {
1998 _hs_cl->do_thread(target); // platform thread
1999 }
2000 }
2001 };
2002
2003 // Supports platform and virtual threads.
2004 // JvmtiVTMSTransitionDisabler is always set by this function.
2005 void
2006 JvmtiHandshake::execute(JvmtiUnitedHandshakeClosure* hs_cl, jthread target) {
2007 JavaThread* current = JavaThread::current();
2008 HandleMark hm(current);
2009
2010 JvmtiVTMSTransitionDisabler disabler(target);
2011 ThreadsListHandle tlh(current);
2012 JavaThread* java_thread = nullptr;
2013 oop thread_obj = nullptr;
2014
2015 jvmtiError err = JvmtiEnvBase::get_threadOop_and_JavaThread(tlh.list(), target, current, &java_thread, &thread_obj);
2016 if (err != JVMTI_ERROR_NONE) {
2017 hs_cl->set_result(err);
2018 return;
2019 }
2020 Handle target_h(current, thread_obj);
2021 execute(hs_cl, &tlh, java_thread, target_h);
2022 }
2023
2024 // Supports platform and virtual threads.
2025 // A virtual thread is always identified by the target_h oop handle.
2026 // The target_jt is always nullptr for an unmounted virtual thread.
2027 // JvmtiVTMSTransitionDisabler has to be set before call to this function.
2028 void
2029 JvmtiHandshake::execute(JvmtiUnitedHandshakeClosure* hs_cl, ThreadsListHandle* tlh,
2030 JavaThread* target_jt, Handle target_h) {
2031 JavaThread* current = JavaThread::current();
2032 bool is_virtual = java_lang_VirtualThread::is_instance(target_h());
2033 bool self = target_jt == current;
2034
2035 assert(!Continuations::enabled() || self || !is_virtual || current->is_VTMS_transition_disabler(), "sanity check");
2036
2037 hs_cl->set_target_jt(target_jt); // can be needed in the virtual thread case
2038 hs_cl->set_is_virtual(is_virtual); // can be needed in the virtual thread case
2039 hs_cl->set_self(self); // needed when suspend is required for non-current target thread
2040
2041 if (is_virtual) { // virtual thread
2042 if (!JvmtiEnvBase::is_vthread_alive(target_h())) {
2043 return;
2044 }
2045 if (target_jt == nullptr) { // unmounted virtual thread
2046 hs_cl->do_vthread(target_h); // execute handshake closure callback on current thread directly
2047 }
2048 }
2049 if (target_jt != nullptr) { // mounted virtual or platform thread
2050 AdapterClosure acl(hs_cl, target_h);
2051 if (self) { // target platform thread is current
2052 acl.do_thread(target_jt); // execute handshake closure callback on current thread directly
2053 } else {
2054 Handshake::execute(&acl, tlh, target_jt); // delegate to Handshake implementation
2055 }
2056 }
2057 }
2058
2059 void
2060 VM_GetThreadListStackTraces::doit() {
2061 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
2062
2063 ResourceMark rm;
2064 ThreadsListHandle tlh;
2065 for (int i = 0; i < _thread_count; ++i) {
2066 jthread jt = _thread_list[i];
2067 JavaThread* java_thread = nullptr;
2068 oop thread_oop = nullptr;
2069 jvmtiError err = JvmtiEnvBase::get_threadOop_and_JavaThread(tlh.list(), jt, nullptr, &java_thread, &thread_oop);
2070
2071 if (err != JVMTI_ERROR_NONE) {
2072 // We got an error code so we don't have a JavaThread *, but
2073 // only return an error from here if we didn't get a valid
2074 // thread_oop.
2075 // In the virtual thread case the get_threadOop_and_JavaThread is expected to correctly set
2076 // the thread_oop and return JVMTI_ERROR_THREAD_NOT_ALIVE which we ignore here.
2077 // The corresponding thread state will be recorded in the jvmtiStackInfo.state.
2078 if (thread_oop == nullptr) {
2079 _collector.set_result(err);
2080 return;
2081 }
2082 // We have a valid thread_oop.
2083 }
2084 _collector.fill_frames(jt, java_thread, thread_oop);
2085 }
2086 _collector.allocate_and_fill_stacks(_thread_count);
2087 }
2088
2089 void
2090 GetSingleStackTraceClosure::doit() {
2091 JavaThread *jt = _target_jt;
2092 oop thread_oop = JNIHandles::resolve_external_guard(_jthread);
2093
2094 if ((jt == nullptr || !jt->is_exiting()) && thread_oop != nullptr) {
2095 ResourceMark rm;
2096 _collector.fill_frames(_jthread, jt, thread_oop);
2097 _collector.allocate_and_fill_stacks(1);
2098 set_result(_collector.result());
2099 }
2100 }
2101
2102 void
2103 GetSingleStackTraceClosure::do_thread(Thread *target) {
2104 assert(_target_jt == JavaThread::cast(target), "sanity check");
2105 doit();
2106 }
2107
2108 void
2109 GetSingleStackTraceClosure::do_vthread(Handle target_h) {
2110 // Use jvmti_vthread() instead of vthread() as target could have temporarily changed
2111 // identity to carrier thread (see VirtualThread.switchToCarrierThread).
2112 assert(_target_jt == nullptr || _target_jt->jvmti_vthread() == target_h(), "sanity check");
2113 doit();
2114 }
2115
2116 void
2117 VM_GetAllStackTraces::doit() {
2118 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
2119
2120 ResourceMark rm;
2121 _final_thread_count = 0;
2122 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *jt = jtiwh.next(); ) {
2123 oop thread_oop = jt->threadObj();
2124 if (thread_oop != nullptr &&
2125 !jt->is_exiting() &&
2126 java_lang_Thread::is_alive(thread_oop) &&
2127 !jt->is_hidden_from_external_view() &&
2128 !thread_oop->is_a(vmClasses::BoundVirtualThread_klass())) {
2129 ++_final_thread_count;
2130 // Handle block of the calling thread is used to create local refs.
2131 _collector.fill_frames((jthread)JNIHandles::make_local(_calling_thread, thread_oop),
2132 jt, thread_oop);
2133 }
2134 }
2135 _collector.allocate_and_fill_stacks(_final_thread_count);
2136 }
2137
2138 // Verifies that the top frame is a java frame in an expected state.
2139 // Deoptimizes frame if needed.
2140 // Checks that the frame method signature matches the return type (tos).
2141 // HandleMark must be defined in the caller only.
2142 // It is to keep a ret_ob_h handle alive after return to the caller.
2143 jvmtiError
2144 JvmtiEnvBase::check_top_frame(Thread* current_thread, JavaThread* java_thread,
2145 jvalue value, TosState tos, Handle* ret_ob_h) {
2146 ResourceMark rm(current_thread);
2147
2148 javaVFrame* jvf = jvf_for_thread_and_depth(java_thread, 0);
2149 NULL_CHECK(jvf, JVMTI_ERROR_NO_MORE_FRAMES);
2150
2151 if (jvf->method()->is_native()) {
2152 return JVMTI_ERROR_OPAQUE_FRAME;
2153 }
2154
2155 // If the frame is a compiled one, need to deoptimize it.
2156 if (jvf->is_compiled_frame()) {
2157 if (!jvf->fr().can_be_deoptimized()) {
2158 return JVMTI_ERROR_OPAQUE_FRAME;
2159 }
2160 Deoptimization::deoptimize_frame(java_thread, jvf->fr().id());
2161 }
2162
2163 // Get information about method return type
2164 Symbol* signature = jvf->method()->signature();
2165
2166 ResultTypeFinder rtf(signature);
2167 TosState fr_tos = as_TosState(rtf.type());
2168 if (fr_tos != tos) {
2169 if (tos != itos || (fr_tos != btos && fr_tos != ztos && fr_tos != ctos && fr_tos != stos)) {
2170 return JVMTI_ERROR_TYPE_MISMATCH;
2171 }
2172 }
2173
2174 // Check that the jobject class matches the return type signature.
2175 jobject jobj = value.l;
2176 if (tos == atos && jobj != nullptr) { // null reference is allowed
2177 Handle ob_h(current_thread, JNIHandles::resolve_external_guard(jobj));
2178 NULL_CHECK(ob_h, JVMTI_ERROR_INVALID_OBJECT);
2179 Klass* ob_k = ob_h()->klass();
2180 NULL_CHECK(ob_k, JVMTI_ERROR_INVALID_OBJECT);
2181
2182 // Method return type signature.
2183 char* ty_sign = 1 + strchr(signature->as_C_string(), JVM_SIGNATURE_ENDFUNC);
2184
2185 if (!VM_GetOrSetLocal::is_assignable(ty_sign, ob_k, current_thread)) {
2186 return JVMTI_ERROR_TYPE_MISMATCH;
2187 }
2188 *ret_ob_h = ob_h;
2189 }
2190 return JVMTI_ERROR_NONE;
2191 } /* end check_top_frame */
2192
2193
2194 // ForceEarlyReturn<type> follows the PopFrame approach in many aspects.
2195 // Main difference is on the last stage in the interpreter.
2196 // The PopFrame stops method execution to continue execution
2197 // from the same method call instruction.
2198 // The ForceEarlyReturn forces return from method so the execution
2199 // continues at the bytecode following the method call.
2200
2201 // thread - NOT protected by ThreadsListHandle and NOT pre-checked
2202
2203 jvmtiError
2204 JvmtiEnvBase::force_early_return(jthread thread, jvalue value, TosState tos) {
2205 JavaThread* current_thread = JavaThread::current();
2206 HandleMark hm(current_thread);
2207
2208 JvmtiVTMSTransitionDisabler disabler(thread);
2209 ThreadsListHandle tlh(current_thread);
2210
2211 JavaThread* java_thread = nullptr;
2212 oop thread_obj = nullptr;
2213 jvmtiError err = get_threadOop_and_JavaThread(tlh.list(), thread, current_thread, &java_thread, &thread_obj);
2214
2215 if (err != JVMTI_ERROR_NONE) {
2216 return err;
2217 }
2218 Handle thread_handle(current_thread, thread_obj);
2219 bool self = java_thread == current_thread;
2220
2221 err = check_non_suspended_or_opaque_frame(java_thread, thread_obj, self);
2222 if (err != JVMTI_ERROR_NONE) {
2223 return err;
2224 }
2225
2226 // retrieve or create the state
2227 JvmtiThreadState* state = JvmtiThreadState::state_for(java_thread);
2228 if (state == nullptr) {
2229 return JVMTI_ERROR_THREAD_NOT_ALIVE;
2230 }
2231
2232 // Eagerly reallocate scalar replaced objects.
2233 EscapeBarrier eb(true, current_thread, java_thread);
2234 if (!eb.deoptimize_objects(0)) {
2235 // Reallocation of scalar replaced objects failed -> return with error
2236 return JVMTI_ERROR_OUT_OF_MEMORY;
2237 }
2238
2239 MutexLocker mu(JvmtiThreadState_lock);
2240 SetForceEarlyReturn op(state, value, tos);
2241 JvmtiHandshake::execute(&op, &tlh, java_thread, thread_handle);
2242 return op.result();
2243 }
2244
2245 void
2246 SetForceEarlyReturn::doit(Thread *target) {
2247 JavaThread* java_thread = JavaThread::cast(target);
2248 Thread* current_thread = Thread::current();
2249 HandleMark hm(current_thread);
2250
2251 if (java_thread->is_exiting()) {
2252 return; /* JVMTI_ERROR_THREAD_NOT_ALIVE (default) */
2253 }
2254
2255 // Check to see if a ForceEarlyReturn was already in progress
2256 if (_state->is_earlyret_pending()) {
2257 // Probably possible for JVMTI clients to trigger this, but the
2258 // JPDA backend shouldn't allow this to happen
2259 _result = JVMTI_ERROR_INTERNAL;
2260 return;
2261 }
2262 {
2263 // The same as for PopFrame. Workaround bug:
2264 // 4812902: popFrame hangs if the method is waiting at a synchronize
2265 // Catch this condition and return an error to avoid hanging.
2266 // Now JVMTI spec allows an implementation to bail out with an opaque
2267 // frame error.
2268 OSThread* osThread = java_thread->osthread();
2269 if (osThread->get_state() == MONITOR_WAIT) {
2270 _result = JVMTI_ERROR_OPAQUE_FRAME;
2271 return;
2272 }
2273 }
2274
2275 Handle ret_ob_h;
2276 _result = JvmtiEnvBase::check_top_frame(current_thread, java_thread, _value, _tos, &ret_ob_h);
2277 if (_result != JVMTI_ERROR_NONE) {
2278 return;
2279 }
2280 assert(_tos != atos || _value.l == nullptr || ret_ob_h() != nullptr,
2281 "return object oop must not be null if jobject is not null");
2282
2283 // Update the thread state to reflect that the top frame must be
2284 // forced to return.
2285 // The current frame will be returned later when the suspended
2286 // thread is resumed and right before returning from VM to Java.
2287 // (see call_VM_base() in assembler_<cpu>.cpp).
2288
2289 _state->set_earlyret_pending();
2290 _state->set_earlyret_oop(ret_ob_h());
2291 _state->set_earlyret_value(_value, _tos);
2292
2293 // Set pending step flag for this early return.
2294 // It is cleared when next step event is posted.
2295 _state->set_pending_step_for_earlyret();
2296 }
2297
2298 void
2299 JvmtiMonitorClosure::do_monitor(ObjectMonitor* mon) {
2300 if ( _error != JVMTI_ERROR_NONE) {
2301 // Error occurred in previous iteration so no need to add
2302 // to the list.
2303 return;
2304 }
2305 // Filter out on stack monitors collected during stack walk.
2306 oop obj = mon->object();
2307
2308 if (obj == nullptr) {
2309 // This can happen if JNI code drops all references to the
2310 // owning object.
2311 return;
2312 }
2313
2314 bool found = false;
2315 for (int j = 0; j < _owned_monitors_list->length(); j++) {
2316 jobject jobj = ((jvmtiMonitorStackDepthInfo*)_owned_monitors_list->at(j))->monitor;
2317 oop check = JNIHandles::resolve(jobj);
2318 if (check == obj) {
2319 // On stack monitor already collected during the stack walk.
2320 found = true;
2321 break;
2322 }
2323 }
2324 if (found == false) {
2325 // This is off stack monitor (e.g. acquired via jni MonitorEnter).
2326 jvmtiError err;
2327 jvmtiMonitorStackDepthInfo *jmsdi;
2328 err = _env->allocate(sizeof(jvmtiMonitorStackDepthInfo), (unsigned char **)&jmsdi);
2329 if (err != JVMTI_ERROR_NONE) {
2330 _error = err;
2331 return;
2332 }
2333 Handle hobj(Thread::current(), obj);
2334 jmsdi->monitor = _env->jni_reference(_calling_thread, hobj);
2335 // stack depth is unknown for this monitor.
2336 jmsdi->stack_depth = -1;
2337 _owned_monitors_list->append(jmsdi);
2338 }
2339 }
2340
2341 GrowableArray<OopHandle>* JvmtiModuleClosure::_tbl = nullptr;
2342
2343 void JvmtiModuleClosure::do_module(ModuleEntry* entry) {
2344 assert_locked_or_safepoint(Module_lock);
2345 OopHandle module = entry->module_handle();
2346 guarantee(module.resolve() != nullptr, "module object is null");
2347 _tbl->push(module);
2348 }
2349
2350 jvmtiError
2351 JvmtiModuleClosure::get_all_modules(JvmtiEnv* env, jint* module_count_ptr, jobject** modules_ptr) {
2352 ResourceMark rm;
2353 MutexLocker mcld(ClassLoaderDataGraph_lock);
2354 MutexLocker ml(Module_lock);
2355
2356 _tbl = new GrowableArray<OopHandle>(77);
2357 if (_tbl == nullptr) {
2358 return JVMTI_ERROR_OUT_OF_MEMORY;
2359 }
2360
2361 // Iterate over all the modules loaded to the system.
2362 ClassLoaderDataGraph::modules_do_keepalive(&do_module);
2363
2364 jint len = _tbl->length();
2365 guarantee(len > 0, "at least one module must be present");
2366
2367 jobject* array = (jobject*)env->jvmtiMalloc((jlong)(len * sizeof(jobject)));
2368 if (array == nullptr) {
2369 return JVMTI_ERROR_OUT_OF_MEMORY;
2370 }
2371 for (jint idx = 0; idx < len; idx++) {
2372 array[idx] = JNIHandles::make_local(_tbl->at(idx).resolve());
2373 }
2374 _tbl = nullptr;
2375 *modules_ptr = array;
2376 *module_count_ptr = len;
2377 return JVMTI_ERROR_NONE;
2378 }
2379
2380 void
2381 UpdateForPopTopFrameClosure::doit(Thread *target) {
2382 Thread* current_thread = Thread::current();
2383 HandleMark hm(current_thread);
2384 JavaThread* java_thread = JavaThread::cast(target);
2385
2386 if (java_thread->is_exiting()) {
2387 return; /* JVMTI_ERROR_THREAD_NOT_ALIVE (default) */
2388 }
2389 assert(java_thread == _state->get_thread(), "Must be");
2390
2391 // Check to see if a PopFrame was already in progress
2392 if (java_thread->popframe_condition() != JavaThread::popframe_inactive) {
2393 // Probably possible for JVMTI clients to trigger this, but the
2394 // JPDA backend shouldn't allow this to happen
2395 _result = JVMTI_ERROR_INTERNAL;
2396 return;
2397 }
2398
2399 // Was workaround bug
2400 // 4812902: popFrame hangs if the method is waiting at a synchronize
2401 // Catch this condition and return an error to avoid hanging.
2402 // Now JVMTI spec allows an implementation to bail out with an opaque frame error.
2403 OSThread* osThread = java_thread->osthread();
2404 if (osThread->get_state() == MONITOR_WAIT) {
2405 _result = JVMTI_ERROR_OPAQUE_FRAME;
2406 return;
2407 }
2408
2409 ResourceMark rm(current_thread);
2410 // Check if there is more than one Java frame in this thread, that the top two frames
2411 // are Java (not native) frames, and that there is no intervening VM frame
2412 int frame_count = 0;
2413 bool is_interpreted[2];
2414 intptr_t *frame_sp[2];
2415 // The 2-nd arg of constructor is needed to stop iterating at java entry frame.
2416 for (vframeStream vfs(java_thread, true, false /* process_frames */); !vfs.at_end(); vfs.next()) {
2417 methodHandle mh(current_thread, vfs.method());
2418 if (mh->is_native()) {
2419 _result = JVMTI_ERROR_OPAQUE_FRAME;
2420 return;
2421 }
2422 is_interpreted[frame_count] = vfs.is_interpreted_frame();
2423 frame_sp[frame_count] = vfs.frame_id();
2424 if (++frame_count > 1) break;
2425 }
2426 if (frame_count < 2) {
2427 // We haven't found two adjacent non-native Java frames on the top.
2428 // There can be two situations here:
2429 // 1. There are no more java frames
2430 // 2. Two top java frames are separated by non-java native frames
2431 if (JvmtiEnvBase::jvf_for_thread_and_depth(java_thread, 1) == nullptr) {
2432 _result = JVMTI_ERROR_NO_MORE_FRAMES;
2433 return;
2434 } else {
2435 // Intervening non-java native or VM frames separate java frames.
2436 // Current implementation does not support this. See bug #5031735.
2437 // In theory it is possible to pop frames in such cases.
2438 _result = JVMTI_ERROR_OPAQUE_FRAME;
2439 return;
2440 }
2441 }
2442
2443 // If any of the top 2 frames is a compiled one, need to deoptimize it
2444 for (int i = 0; i < 2; i++) {
2445 if (!is_interpreted[i]) {
2446 Deoptimization::deoptimize_frame(java_thread, frame_sp[i]);
2447 }
2448 }
2449
2450 // Update the thread state to reflect that the top frame is popped
2451 // so that cur_stack_depth is maintained properly and all frameIDs
2452 // are invalidated.
2453 // The current frame will be popped later when the suspended thread
2454 // is resumed and right before returning from VM to Java.
2455 // (see call_VM_base() in assembler_<cpu>.cpp).
2456
2457 // It's fine to update the thread state here because no JVMTI events
2458 // shall be posted for this PopFrame.
2459
2460 _state->update_for_pop_top_frame();
2461 java_thread->set_popframe_condition(JavaThread::popframe_pending_bit);
2462 // Set pending step flag for this popframe and it is cleared when next
2463 // step event is posted.
2464 _state->set_pending_step_for_popframe();
2465 _result = JVMTI_ERROR_NONE;
2466 }
2467
2468 void
2469 SetFramePopClosure::do_thread(Thread *target) {
2470 Thread* current = Thread::current();
2471 ResourceMark rm(current); // vframes are resource allocated
2472 JavaThread* java_thread = JavaThread::cast(target);
2473
2474 if (java_thread->is_exiting()) {
2475 return; // JVMTI_ERROR_THREAD_NOT_ALIVE (default)
2476 }
2477
2478 if (!_self && !java_thread->is_suspended()) {
2479 _result = JVMTI_ERROR_THREAD_NOT_SUSPENDED;
2480 return;
2481 }
2482 if (!java_thread->has_last_Java_frame()) {
2483 _result = JVMTI_ERROR_NO_MORE_FRAMES;
2484 return;
2485 }
2486 assert(_state->get_thread_or_saved() == java_thread, "Must be");
2487
2488 RegisterMap reg_map(java_thread,
2489 RegisterMap::UpdateMap::include,
2490 RegisterMap::ProcessFrames::skip,
2491 RegisterMap::WalkContinuation::include);
2492 javaVFrame* jvf = JvmtiEnvBase::get_cthread_last_java_vframe(java_thread, ®_map);
2493 _result = ((JvmtiEnvBase*)_env)->set_frame_pop(_state, jvf, _depth);
2494 }
2495
2496 void
2497 SetFramePopClosure::do_vthread(Handle target_h) {
2498 Thread* current = Thread::current();
2499 ResourceMark rm(current); // vframes are resource allocated
2500
2501 if (!_self && !JvmtiVTSuspender::is_vthread_suspended(target_h())) {
2502 _result = JVMTI_ERROR_THREAD_NOT_SUSPENDED;
2503 return;
2504 }
2505 javaVFrame *jvf = JvmtiEnvBase::get_vthread_jvf(target_h());
2506 _result = ((JvmtiEnvBase*)_env)->set_frame_pop(_state, jvf, _depth);
2507 }
2508
2509 void
2510 GetOwnedMonitorInfoClosure::do_thread(Thread *target) {
2511 JavaThread *jt = JavaThread::cast(target);
2512 if (!jt->is_exiting() && (jt->threadObj() != nullptr)) {
2513 _result = ((JvmtiEnvBase *)_env)->get_owned_monitors(_calling_thread,
2514 jt,
2515 _owned_monitors_list);
2516 }
2517 }
2518
2519 void
2520 GetOwnedMonitorInfoClosure::do_vthread(Handle target_h) {
2521 Thread* current = Thread::current();
2522 ResourceMark rm(current); // vframes are resource allocated
2523 HandleMark hm(current);
2524
2525 javaVFrame *jvf = JvmtiEnvBase::get_vthread_jvf(target_h());
2526
2527 if (_target_jt == nullptr || (!_target_jt->is_exiting() && _target_jt->threadObj() != nullptr)) {
2528 _result = ((JvmtiEnvBase *)_env)->get_owned_monitors(_calling_thread,
2529 _target_jt,
2530 jvf,
2531 _owned_monitors_list,
2532 target_h());
2533 }
2534 }
2535
2536 void
2537 GetCurrentContendedMonitorClosure::do_thread(Thread *target) {
2538 JavaThread *jt = JavaThread::cast(target);
2539 if (!jt->is_exiting() && (jt->threadObj() != nullptr)) {
2540 _result = ((JvmtiEnvBase *)_env)->get_current_contended_monitor(_calling_thread,
2541 jt,
2542 _owned_monitor_ptr,
2543 _is_virtual);
2544 }
2545 }
2546
2547 void
2548 GetCurrentContendedMonitorClosure::do_vthread(Handle target_h) {
2549 if (_target_jt == nullptr) {
2550 oop cont = java_lang_VirtualThread::continuation(target_h());
2551 assert(cont != nullptr, "vthread with no continuation");
2552 stackChunkOop chunk = jdk_internal_vm_Continuation::tail(cont);
2553 assert(chunk != nullptr, "unmounted vthread should have a chunk");
2554 if (chunk->current_pending_monitor() != nullptr) {
2555 *_owned_monitor_ptr = JNIHandles::make_local(_calling_thread, chunk->current_pending_monitor()->object());
2556 }
2557 _result = JVMTI_ERROR_NONE; // target virtual thread is unmounted
2558 return;
2559 }
2560 // mounted virtual thread case
2561 do_thread(_target_jt);
2562 }
2563
2564 void
2565 GetStackTraceClosure::do_thread(Thread *target) {
2566 Thread* current = Thread::current();
2567 ResourceMark rm(current);
2568
2569 JavaThread *jt = JavaThread::cast(target);
2570 if (!jt->is_exiting() && jt->threadObj() != nullptr) {
2571 _result = ((JvmtiEnvBase *)_env)->get_stack_trace(jt,
2572 _start_depth, _max_count,
2573 _frame_buffer, _count_ptr);
2574 }
2575 }
2576
2577 void
2578 GetStackTraceClosure::do_vthread(Handle target_h) {
2579 Thread* current = Thread::current();
2580 ResourceMark rm(current);
2581
2582 javaVFrame *jvf = JvmtiEnvBase::get_vthread_jvf(target_h());
2583 _result = ((JvmtiEnvBase *)_env)->get_stack_trace(jvf,
2584 _start_depth, _max_count,
2585 _frame_buffer, _count_ptr);
2586 }
2587
2588 #ifdef ASSERT
2589 void
2590 PrintStackTraceClosure::do_thread_impl(Thread *target) {
2591 JavaThread *java_thread = JavaThread::cast(target);
2592 Thread *current_thread = Thread::current();
2593
2594 ResourceMark rm (current_thread);
2595 const char* tname = JvmtiTrace::safe_get_thread_name(java_thread);
2596 oop t_oop = java_thread->jvmti_vthread();
2597 t_oop = t_oop == nullptr ? java_thread->threadObj() : t_oop;
2598 bool is_vt_suspended = java_lang_VirtualThread::is_instance(t_oop) && JvmtiVTSuspender::is_vthread_suspended(t_oop);
2599
2600 log_error(jvmti)("%s(%s) exiting: %d is_susp: %d is_thread_susp: %d is_vthread_susp: %d "
2601 "is_VTMS_transition_disabler: %d, is_in_VTMS_transition = %d\n",
2602 tname, java_thread->name(), java_thread->is_exiting(),
2603 java_thread->is_suspended(), java_thread->is_carrier_thread_suspended(), is_vt_suspended,
2604 java_thread->is_VTMS_transition_disabler(), java_thread->is_in_VTMS_transition());
2605
2606 if (java_thread->has_last_Java_frame()) {
2607 RegisterMap reg_map(java_thread,
2608 RegisterMap::UpdateMap::include,
2609 RegisterMap::ProcessFrames::include,
2610 RegisterMap::WalkContinuation::skip);
2611 ResourceMark rm(current_thread);
2612 HandleMark hm(current_thread);
2613 javaVFrame *jvf = java_thread->last_java_vframe(®_map);
2614 while (jvf != nullptr) {
2615 log_error(jvmti)(" %s:%d",
2616 jvf->method()->external_name(),
2617 jvf->method()->line_number_from_bci(jvf->bci()));
2618 jvf = jvf->java_sender();
2619 }
2620 }
2621 log_error(jvmti)("\n");
2622 }
2623
2624 void
2625 PrintStackTraceClosure::do_thread(Thread *target) {
2626 JavaThread *java_thread = JavaThread::cast(target);
2627 Thread *current_thread = Thread::current();
2628
2629 assert(SafepointSynchronize::is_at_safepoint() ||
2630 java_thread->is_handshake_safe_for(current_thread),
2631 "call by myself / at safepoint / at handshake");
2632
2633 PrintStackTraceClosure::do_thread_impl(target);
2634 }
2635 #endif
2636
2637 void
2638 GetFrameCountClosure::do_thread(Thread *target) {
2639 JavaThread* jt = JavaThread::cast(target);
2640 assert(target == jt, "just checking");
2641
2642 if (!jt->is_exiting() && jt->threadObj() != nullptr) {
2643 _result = ((JvmtiEnvBase*)_env)->get_frame_count(jt, _count_ptr);
2644 }
2645 }
2646
2647 void
2648 GetFrameCountClosure::do_vthread(Handle target_h) {
2649 _result = ((JvmtiEnvBase*)_env)->get_frame_count(target_h(), _count_ptr);
2650 }
2651
2652 void
2653 GetFrameLocationClosure::do_thread(Thread *target) {
2654 JavaThread *jt = JavaThread::cast(target);
2655 assert(target == jt, "just checking");
2656
2657 if (!jt->is_exiting() && jt->threadObj() != nullptr) {
2658 _result = ((JvmtiEnvBase*)_env)->get_frame_location(jt, _depth,
2659 _method_ptr, _location_ptr);
2660 }
2661 }
2662
2663 void
2664 GetFrameLocationClosure::do_vthread(Handle target_h) {
2665 _result = ((JvmtiEnvBase*)_env)->get_frame_location(target_h(), _depth,
2666 _method_ptr, _location_ptr);
2667 }