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