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