1 /*
2 * Copyright (c) 2003, 2021, 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.hpp"
28 #include "classfile/moduleEntry.hpp"
29 #include "jvmtifiles/jvmtiEnv.hpp"
30 #include "memory/iterator.hpp"
31 #include "memory/resourceArea.hpp"
32 #include "oops/klass.inline.hpp"
33 #include "oops/objArrayKlass.hpp"
34 #include "oops/objArrayOop.hpp"
35 #include "oops/oop.inline.hpp"
36 #include "oops/oopHandle.inline.hpp"
37 #include "prims/jvmtiEnvBase.hpp"
38 #include "prims/jvmtiEventController.inline.hpp"
39 #include "prims/jvmtiExtensions.hpp"
40 #include "prims/jvmtiImpl.hpp"
41 #include "prims/jvmtiManageCapabilities.hpp"
42 #include "prims/jvmtiTagMap.hpp"
43 #include "prims/jvmtiThreadState.inline.hpp"
44 #include "runtime/biasedLocking.hpp"
45 #include "runtime/deoptimization.hpp"
46 #include "runtime/frame.inline.hpp"
47 #include "runtime/handles.inline.hpp"
48 #include "runtime/interfaceSupport.inline.hpp"
49 #include "runtime/jfieldIDWorkaround.hpp"
50 #include "runtime/jniHandles.inline.hpp"
51 #include "runtime/objectMonitor.inline.hpp"
52 #include "runtime/osThread.hpp"
53 #include "runtime/signature.hpp"
54 #include "runtime/thread.inline.hpp"
55 #include "runtime/threadSMR.hpp"
56 #include "runtime/vframe.inline.hpp"
57 #include "runtime/vframe_hp.hpp"
58 #include "runtime/vmThread.hpp"
59 #include "runtime/vmOperations.hpp"
60
61
62 ///////////////////////////////////////////////////////////////
63 //
64 // JvmtiEnvBase
65 //
66
67 JvmtiEnvBase* JvmtiEnvBase::_head_environment = NULL;
68
69 bool JvmtiEnvBase::_globally_initialized = false;
70 volatile bool JvmtiEnvBase::_needs_clean_up = false;
71
72 jvmtiPhase JvmtiEnvBase::_phase = JVMTI_PHASE_PRIMORDIAL;
73
74 volatile int JvmtiEnvBase::_dying_thread_env_iteration_count = 0;
75
76 extern jvmtiInterface_1_ jvmti_Interface;
77 extern jvmtiInterface_1_ jvmtiTrace_Interface;
78
79
80 // perform initializations that must occur before any JVMTI environments
81 // are released but which should only be initialized once (no matter
82 // how many environments are created).
83 void
84 JvmtiEnvBase::globally_initialize() {
85 assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(), "sanity check");
86 assert(_globally_initialized == false, "bad call");
87
88 JvmtiManageCapabilities::initialize();
89
90 // register extension functions and events
91 JvmtiExtensions::register_extensions();
92
93 #ifdef JVMTI_TRACE
94 JvmtiTrace::initialize();
95 #endif
96
97 _globally_initialized = true;
98 }
99
100
101 void
102 JvmtiEnvBase::initialize() {
103 assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(), "sanity check");
104
105 // Add this environment to the end of the environment list (order is important)
106 {
107 // This block of code must not contain any safepoints, as list deallocation
108 // (which occurs at a safepoint) cannot occur simultaneously with this list
109 // addition. Note: NoSafepointVerifier cannot, currently, be used before
110 // threads exist.
111 JvmtiEnvIterator it;
112 JvmtiEnvBase *previous_env = NULL;
113 for (JvmtiEnvBase* env = it.first(); env != NULL; env = it.next(env)) {
114 previous_env = env;
115 }
116 if (previous_env == NULL) {
117 _head_environment = this;
118 } else {
119 previous_env->set_next_environment(this);
120 }
121 }
122
123 if (_globally_initialized == false) {
124 globally_initialize();
125 }
126 }
127
128 jvmtiPhase
129 JvmtiEnvBase::phase() {
130 // For the JVMTI environments possessed the can_generate_early_vmstart:
131 // replace JVMTI_PHASE_PRIMORDIAL with JVMTI_PHASE_START
132 if (_phase == JVMTI_PHASE_PRIMORDIAL &&
133 JvmtiExport::early_vmstart_recorded() &&
134 early_vmstart_env()) {
135 return JVMTI_PHASE_START;
136 }
137 return _phase; // Normal case
138 }
139
140 bool
141 JvmtiEnvBase::is_valid() {
142 jint value = 0;
143
144 // This object might not be a JvmtiEnvBase so we can't assume
145 // the _magic field is properly aligned. Get the value in a safe
146 // way and then check against JVMTI_MAGIC.
147
148 switch (sizeof(_magic)) {
149 case 2:
150 value = Bytes::get_native_u2((address)&_magic);
151 break;
152
153 case 4:
154 value = Bytes::get_native_u4((address)&_magic);
155 break;
156
157 case 8:
158 value = Bytes::get_native_u8((address)&_magic);
159 break;
160
161 default:
162 guarantee(false, "_magic field is an unexpected size");
163 }
164
165 return value == JVMTI_MAGIC;
166 }
167
168
169 bool
170 JvmtiEnvBase::use_version_1_0_semantics() {
171 int major, minor, micro;
172
173 JvmtiExport::decode_version_values(_version, &major, &minor, µ);
174 return major == 1 && minor == 0; // micro version doesn't matter here
175 }
176
177
178 bool
179 JvmtiEnvBase::use_version_1_1_semantics() {
180 int major, minor, micro;
181
182 JvmtiExport::decode_version_values(_version, &major, &minor, µ);
183 return major == 1 && minor == 1; // micro version doesn't matter here
184 }
185
186 bool
187 JvmtiEnvBase::use_version_1_2_semantics() {
188 int major, minor, micro;
189
190 JvmtiExport::decode_version_values(_version, &major, &minor, µ);
191 return major == 1 && minor == 2; // micro version doesn't matter here
192 }
193
194
195 JvmtiEnvBase::JvmtiEnvBase(jint version) : _env_event_enable() {
196 _version = version;
197 _env_local_storage = NULL;
198 _tag_map = NULL;
199 _native_method_prefix_count = 0;
200 _native_method_prefixes = NULL;
201 _next = NULL;
202 _class_file_load_hook_ever_enabled = false;
203
204 // Moot since ClassFileLoadHook not yet enabled.
205 // But "true" will give a more predictable ClassFileLoadHook behavior
206 // for environment creation during ClassFileLoadHook.
207 _is_retransformable = true;
208
209 // all callbacks initially NULL
210 memset(&_event_callbacks, 0, sizeof(jvmtiEventCallbacks));
211 memset(&_ext_event_callbacks, 0, sizeof(jvmtiExtEventCallbacks));
212
213 // all capabilities initially off
214 memset(&_current_capabilities, 0, sizeof(_current_capabilities));
215
216 // all prohibited capabilities initially off
217 memset(&_prohibited_capabilities, 0, sizeof(_prohibited_capabilities));
218
219 _magic = JVMTI_MAGIC;
220
221 JvmtiEventController::env_initialize((JvmtiEnv*)this);
222
223 #ifdef JVMTI_TRACE
224 _jvmti_external.functions = TraceJVMTI != NULL ? &jvmtiTrace_Interface : &jvmti_Interface;
225 #else
226 _jvmti_external.functions = &jvmti_Interface;
227 #endif
228 }
229
230
231 void
232 JvmtiEnvBase::dispose() {
233
234 #ifdef JVMTI_TRACE
235 JvmtiTrace::shutdown();
236 #endif
237
238 // Dispose of event info and let the event controller call us back
239 // in a locked state (env_dispose, below)
240 JvmtiEventController::env_dispose(this);
241 }
242
243 void
244 JvmtiEnvBase::env_dispose() {
245 assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(), "sanity check");
246
247 // We have been entered with all events disabled on this environment.
248 // A race to re-enable events (by setting callbacks) is prevented by
249 // checking for a valid environment when setting callbacks (while
250 // holding the JvmtiThreadState_lock).
251
252 // Mark as invalid.
253 _magic = DISPOSED_MAGIC;
254
255 // Relinquish all capabilities.
256 jvmtiCapabilities *caps = get_capabilities();
257 JvmtiManageCapabilities::relinquish_capabilities(caps, caps, caps);
258
259 // Same situation as with events (see above)
260 set_native_method_prefixes(0, NULL);
261
262 JvmtiTagMap* tag_map_to_clear = tag_map_acquire();
263 // A tag map can be big, clear it now to save memory until
264 // the destructor runs.
265 if (tag_map_to_clear != NULL) {
266 tag_map_to_clear->clear();
267 }
268
269 _needs_clean_up = true;
270 }
271
272
273 JvmtiEnvBase::~JvmtiEnvBase() {
274 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
275
276 // There is a small window of time during which the tag map of a
277 // disposed environment could have been reallocated.
278 // Make sure it is gone.
279 JvmtiTagMap* tag_map_to_deallocate = _tag_map;
280 set_tag_map(NULL);
281 // A tag map can be big, deallocate it now
282 if (tag_map_to_deallocate != NULL) {
283 delete tag_map_to_deallocate;
284 }
285
286 _magic = BAD_MAGIC;
287 }
288
289
290 void
291 JvmtiEnvBase::periodic_clean_up() {
292 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
293
294 // JvmtiEnvBase reference is saved in JvmtiEnvThreadState. So
295 // clean up JvmtiThreadState before deleting JvmtiEnv pointer.
296 JvmtiThreadState::periodic_clean_up();
297
298 // Unlink all invalid environments from the list of environments
299 // and deallocate them
300 JvmtiEnvIterator it;
301 JvmtiEnvBase* previous_env = NULL;
302 JvmtiEnvBase* env = it.first();
303 while (env != NULL) {
304 if (env->is_valid()) {
305 previous_env = env;
306 env = it.next(env);
307 } else {
308 // This one isn't valid, remove it from the list and deallocate it
309 JvmtiEnvBase* defunct_env = env;
310 env = it.next(env);
311 if (previous_env == NULL) {
312 _head_environment = env;
313 } else {
314 previous_env->set_next_environment(env);
315 }
316 delete defunct_env;
317 }
318 }
319
320 }
321
322
323 void
324 JvmtiEnvBase::check_for_periodic_clean_up() {
325 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
326
327 class ThreadInsideIterationClosure: public ThreadClosure {
328 private:
329 bool _inside;
330 public:
331 ThreadInsideIterationClosure() : _inside(false) {};
332
333 void do_thread(Thread* thread) {
334 _inside |= thread->is_inside_jvmti_env_iteration();
335 }
336
337 bool is_inside_jvmti_env_iteration() {
338 return _inside;
339 }
340 };
341
342 if (_needs_clean_up) {
343 // Check if we are currently iterating environment,
344 // deallocation should not occur if we are
345 ThreadInsideIterationClosure tiic;
346 Threads::threads_do(&tiic);
347 if (!tiic.is_inside_jvmti_env_iteration() &&
348 !is_inside_dying_thread_env_iteration()) {
349 _needs_clean_up = false;
350 JvmtiEnvBase::periodic_clean_up();
351 }
352 }
353 }
354
355
356 void
357 JvmtiEnvBase::record_first_time_class_file_load_hook_enabled() {
358 assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(),
359 "sanity check");
360
361 if (!_class_file_load_hook_ever_enabled) {
362 _class_file_load_hook_ever_enabled = true;
363
364 if (get_capabilities()->can_retransform_classes) {
365 _is_retransformable = true;
366 } else {
367 _is_retransformable = false;
368
369 // cannot add retransform capability after ClassFileLoadHook has been enabled
370 get_prohibited_capabilities()->can_retransform_classes = 1;
371 }
372 }
373 }
374
375
376 void
377 JvmtiEnvBase::record_class_file_load_hook_enabled() {
378 if (!_class_file_load_hook_ever_enabled) {
379 if (Threads::number_of_threads() == 0) {
380 record_first_time_class_file_load_hook_enabled();
381 } else {
382 MutexLocker mu(JvmtiThreadState_lock);
383 record_first_time_class_file_load_hook_enabled();
384 }
385 }
386 }
387
388
389 jvmtiError
390 JvmtiEnvBase::set_native_method_prefixes(jint prefix_count, char** prefixes) {
391 assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(),
392 "sanity check");
393
394 int old_prefix_count = get_native_method_prefix_count();
395 char **old_prefixes = get_native_method_prefixes();
396
397 // allocate and install the new prefixex
398 if (prefix_count == 0 || !is_valid()) {
399 _native_method_prefix_count = 0;
400 _native_method_prefixes = NULL;
401 } else {
402 // there are prefixes, allocate an array to hold them, and fill it
403 char** new_prefixes = (char**)os::malloc((prefix_count) * sizeof(char*), mtInternal);
404 if (new_prefixes == NULL) {
405 return JVMTI_ERROR_OUT_OF_MEMORY;
406 }
407 for (int i = 0; i < prefix_count; i++) {
408 char* prefix = prefixes[i];
409 if (prefix == NULL) {
410 for (int j = 0; j < (i-1); j++) {
411 os::free(new_prefixes[j]);
412 }
413 os::free(new_prefixes);
414 return JVMTI_ERROR_NULL_POINTER;
415 }
416 prefix = os::strdup(prefixes[i]);
417 if (prefix == NULL) {
418 for (int j = 0; j < (i-1); j++) {
419 os::free(new_prefixes[j]);
420 }
421 os::free(new_prefixes);
422 return JVMTI_ERROR_OUT_OF_MEMORY;
423 }
424 new_prefixes[i] = prefix;
425 }
426 _native_method_prefix_count = prefix_count;
427 _native_method_prefixes = new_prefixes;
428 }
429
430 // now that we know the new prefixes have been successfully installed we can
431 // safely remove the old ones
432 if (old_prefix_count != 0) {
433 for (int i = 0; i < old_prefix_count; i++) {
434 os::free(old_prefixes[i]);
435 }
436 os::free(old_prefixes);
437 }
438
439 return JVMTI_ERROR_NONE;
440 }
441
442
443 // Collect all the prefixes which have been set in any JVM TI environments
444 // by the SetNativeMethodPrefix(es) functions. Be sure to maintain the
445 // order of environments and the order of prefixes within each environment.
446 // Return in a resource allocated array.
447 char**
448 JvmtiEnvBase::get_all_native_method_prefixes(int* count_ptr) {
449 assert(Threads::number_of_threads() == 0 ||
450 SafepointSynchronize::is_at_safepoint() ||
451 JvmtiThreadState_lock->is_locked(),
452 "sanity check");
453
454 int total_count = 0;
455 GrowableArray<char*>* prefix_array =new GrowableArray<char*>(5);
456
457 JvmtiEnvIterator it;
458 for (JvmtiEnvBase* env = it.first(); env != NULL; env = it.next(env)) {
459 int prefix_count = env->get_native_method_prefix_count();
460 char** prefixes = env->get_native_method_prefixes();
461 for (int j = 0; j < prefix_count; j++) {
462 // retrieve a prefix and so that it is safe against asynchronous changes
463 // copy it into the resource area
464 char* prefix = prefixes[j];
465 char* prefix_copy = NEW_RESOURCE_ARRAY(char, strlen(prefix)+1);
466 strcpy(prefix_copy, prefix);
467 prefix_array->at_put_grow(total_count++, prefix_copy);
468 }
469 }
470
471 char** all_prefixes = NEW_RESOURCE_ARRAY(char*, total_count);
472 char** p = all_prefixes;
473 for (int i = 0; i < total_count; ++i) {
474 *p++ = prefix_array->at(i);
475 }
476 *count_ptr = total_count;
477 return all_prefixes;
478 }
479
480 void
481 JvmtiEnvBase::set_event_callbacks(const jvmtiEventCallbacks* callbacks,
482 jint size_of_callbacks) {
483 assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(), "sanity check");
484
485 size_t byte_cnt = sizeof(jvmtiEventCallbacks);
486
487 // clear in either case to be sure we got any gap between sizes
488 memset(&_event_callbacks, 0, byte_cnt);
489
490 // Now that JvmtiThreadState_lock is held, prevent a possible race condition where events
491 // are re-enabled by a call to set event callbacks where the DisposeEnvironment
492 // occurs after the boiler-plate environment check and before the lock is acquired.
493 if (callbacks != NULL && is_valid()) {
494 if (size_of_callbacks < (jint)byte_cnt) {
495 byte_cnt = size_of_callbacks;
496 }
497 memcpy(&_event_callbacks, callbacks, byte_cnt);
498 }
499 }
500
501
502 // In the fullness of time, all users of the method should instead
503 // directly use allocate, besides being cleaner and faster, this will
504 // mean much better out of memory handling
505 unsigned char *
506 JvmtiEnvBase::jvmtiMalloc(jlong size) {
507 unsigned char* mem = NULL;
508 jvmtiError result = allocate(size, &mem);
509 assert(result == JVMTI_ERROR_NONE, "Allocate failed");
510 return mem;
511 }
512
513
514 // Handle management
515
516 jobject JvmtiEnvBase::jni_reference(Handle hndl) {
517 return JNIHandles::make_local(hndl());
518 }
519
520 jobject JvmtiEnvBase::jni_reference(JavaThread *thread, Handle hndl) {
521 return JNIHandles::make_local(thread, hndl());
522 }
523
524 void JvmtiEnvBase::destroy_jni_reference(jobject jobj) {
525 JNIHandles::destroy_local(jobj);
526 }
527
528 void JvmtiEnvBase::destroy_jni_reference(JavaThread *thread, jobject jobj) {
529 JNIHandles::destroy_local(jobj); // thread is unused.
530 }
531
532 //
533 // Threads
534 //
535
536 jobject *
537 JvmtiEnvBase::new_jobjectArray(int length, Handle *handles) {
538 if (length == 0) {
539 return NULL;
540 }
541
542 jobject *objArray = (jobject *) jvmtiMalloc(sizeof(jobject) * length);
543 NULL_CHECK(objArray, NULL);
544
545 for (int i=0; i<length; i++) {
546 objArray[i] = jni_reference(handles[i]);
547 }
548 return objArray;
549 }
550
551 jthread *
552 JvmtiEnvBase::new_jthreadArray(int length, Handle *handles) {
553 return (jthread *) new_jobjectArray(length,handles);
554 }
555
556 jthreadGroup *
557 JvmtiEnvBase::new_jthreadGroupArray(int length, Handle *handles) {
558 return (jthreadGroup *) new_jobjectArray(length,handles);
559 }
560
561 // return the vframe on the specified thread and depth, NULL if no such frame
562 // The thread and the oops in the returned vframe might not have been process.
563 vframe*
564 JvmtiEnvBase::vframeForNoProcess(JavaThread* java_thread, jint depth) {
565 if (!java_thread->has_last_Java_frame()) {
566 return NULL;
567 }
568 RegisterMap reg_map(java_thread, true /* update_map */, false /* process_frames */);
569 vframe *vf = java_thread->last_java_vframe(®_map);
570 int d = 0;
571 while ((vf != NULL) && (d < depth)) {
572 vf = vf->java_sender();
573 d++;
574 }
575 return vf;
576 }
577
578
579 //
580 // utilities: JNI objects
581 //
582
583
584 jclass
585 JvmtiEnvBase::get_jni_class_non_null(Klass* k) {
586 assert(k != NULL, "k != NULL");
587 Thread *thread = Thread::current();
588 return (jclass)jni_reference(Handle(thread, k->java_mirror()));
589 }
590
591 //
592 // Field Information
593 //
594
595 bool
596 JvmtiEnvBase::get_field_descriptor(Klass* k, jfieldID field, fieldDescriptor* fd) {
597 if (!jfieldIDWorkaround::is_valid_jfieldID(k, field)) {
598 return false;
599 }
600 bool found = false;
601 if (jfieldIDWorkaround::is_static_jfieldID(field)) {
602 JNIid* id = jfieldIDWorkaround::from_static_jfieldID(field);
603 found = id->find_local_field(fd);
604 } else {
605 // Non-static field. The fieldID is really the offset of the field within the object.
606 int offset = jfieldIDWorkaround::from_instance_jfieldID(k, field);
607 found = InstanceKlass::cast(k)->find_field_from_offset(offset, false, fd);
608 }
609 return found;
610 }
611
612 //
613 // Object Monitor Information
614 //
615
616 //
617 // Count the number of objects for a lightweight monitor. The hobj
618 // parameter is object that owns the monitor so this routine will
619 // count the number of times the same object was locked by frames
620 // in java_thread.
621 //
622 jint
623 JvmtiEnvBase::count_locked_objects(JavaThread *java_thread, Handle hobj) {
624 jint ret = 0;
625 if (!java_thread->has_last_Java_frame()) {
626 return ret; // no Java frames so no monitors
627 }
628
629 Thread* current_thread = Thread::current();
630 ResourceMark rm(current_thread);
631 HandleMark hm(current_thread);
632 RegisterMap reg_map(java_thread);
633
634 for(javaVFrame *jvf=java_thread->last_java_vframe(®_map); jvf != NULL;
635 jvf = jvf->java_sender()) {
636 GrowableArray<MonitorInfo*>* mons = jvf->monitors();
637 if (!mons->is_empty()) {
638 for (int i = 0; i < mons->length(); i++) {
639 MonitorInfo *mi = mons->at(i);
640 if (mi->owner_is_scalar_replaced()) continue;
641
642 // see if owner of the monitor is our object
643 if (mi->owner() != NULL && mi->owner() == hobj()) {
644 ret++;
645 }
646 }
647 }
648 }
649 return ret;
650 }
651
652
653
654 jvmtiError
655 JvmtiEnvBase::get_current_contended_monitor(JavaThread *calling_thread, JavaThread *java_thread, jobject *monitor_ptr) {
656 Thread *current_thread = Thread::current();
657 assert(java_thread->is_handshake_safe_for(current_thread),
658 "call by myself or at handshake");
659 oop obj = NULL;
660 // The ObjectMonitor* can't be async deflated since we are either
661 // at a safepoint or the calling thread is operating on itself so
662 // it cannot leave the underlying wait()/enter() call.
663 ObjectMonitor *mon = java_thread->current_waiting_monitor();
664 if (mon == NULL) {
665 // thread is not doing an Object.wait() call
666 mon = java_thread->current_pending_monitor();
667 if (mon != NULL) {
668 // The thread is trying to enter() an ObjectMonitor.
669 obj = mon->object();
670 assert(obj != NULL, "ObjectMonitor should have a valid object!");
671 }
672 // implied else: no contended ObjectMonitor
673 } else {
674 // thread is doing an Object.wait() call
675 obj = mon->object();
676 assert(obj != NULL, "Object.wait() should have an object");
677 }
678
679 if (obj == NULL) {
680 *monitor_ptr = NULL;
681 } else {
682 HandleMark hm(current_thread);
683 Handle hobj(current_thread, obj);
684 *monitor_ptr = jni_reference(calling_thread, hobj);
685 }
686 return JVMTI_ERROR_NONE;
687 }
688
689
690 jvmtiError
691 JvmtiEnvBase::get_owned_monitors(JavaThread *calling_thread, JavaThread* java_thread,
692 GrowableArray<jvmtiMonitorStackDepthInfo*> *owned_monitors_list) {
693 // Note:
694 // calling_thread is the thread that requested the list of monitors for java_thread.
695 // java_thread is the thread owning the monitors.
696 // current_thread is the thread executing this code, can be a non-JavaThread (e.g. VM Thread).
697 // And they all may be different threads.
698 jvmtiError err = JVMTI_ERROR_NONE;
699 Thread *current_thread = Thread::current();
700 assert(java_thread->is_handshake_safe_for(current_thread),
701 "call by myself or at handshake");
702
703 if (java_thread->has_last_Java_frame()) {
704 ResourceMark rm(current_thread);
705 HandleMark hm(current_thread);
706 RegisterMap reg_map(java_thread);
707
708 int depth = 0;
709 for (javaVFrame *jvf = java_thread->last_java_vframe(®_map); jvf != NULL;
710 jvf = jvf->java_sender()) {
711 if (MaxJavaStackTraceDepth == 0 || depth++ < MaxJavaStackTraceDepth) { // check for stack too deep
712 // add locked objects for this frame into list
713 err = get_locked_objects_in_frame(calling_thread, java_thread, jvf, owned_monitors_list, depth-1);
714 if (err != JVMTI_ERROR_NONE) {
715 return err;
716 }
717 }
718 }
719 }
720
721 // Get off stack monitors. (e.g. acquired via jni MonitorEnter).
722 JvmtiMonitorClosure jmc(calling_thread, owned_monitors_list, this);
723 ObjectSynchronizer::monitors_iterate(&jmc, java_thread);
724 err = jmc.error();
725
726 return err;
727 }
728
729 // Save JNI local handles for any objects that this frame owns.
730 jvmtiError
731 JvmtiEnvBase::get_locked_objects_in_frame(JavaThread* calling_thread, JavaThread* java_thread,
732 javaVFrame *jvf, GrowableArray<jvmtiMonitorStackDepthInfo*>* owned_monitors_list, jint stack_depth) {
733 jvmtiError err = JVMTI_ERROR_NONE;
734 Thread* current_thread = Thread::current();
735 ResourceMark rm(current_thread);
736 HandleMark hm(current_thread);
737
738 GrowableArray<MonitorInfo*>* mons = jvf->monitors();
739 if (mons->is_empty()) {
740 return err; // this javaVFrame holds no monitors
741 }
742
743 oop wait_obj = NULL;
744 {
745 // The ObjectMonitor* can't be async deflated since we are either
746 // at a safepoint or the calling thread is operating on itself so
747 // it cannot leave the underlying wait() call.
748 // Save object of current wait() call (if any) for later comparison.
749 ObjectMonitor *mon = java_thread->current_waiting_monitor();
750 if (mon != NULL) {
751 wait_obj = mon->object();
752 }
753 }
754 oop pending_obj = NULL;
755 {
756 // The ObjectMonitor* can't be async deflated since we are either
757 // at a safepoint or the calling thread is operating on itself so
758 // it cannot leave the underlying enter() call.
759 // Save object of current enter() call (if any) for later comparison.
760 ObjectMonitor *mon = java_thread->current_pending_monitor();
761 if (mon != NULL) {
762 pending_obj = mon->object();
763 }
764 }
765
766 for (int i = 0; i < mons->length(); i++) {
767 MonitorInfo *mi = mons->at(i);
768
769 if (mi->owner_is_scalar_replaced()) continue;
770
771 oop obj = mi->owner();
772 if (obj == NULL) {
773 // this monitor doesn't have an owning object so skip it
774 continue;
775 }
776
777 if (wait_obj == obj) {
778 // the thread is waiting on this monitor so it isn't really owned
779 continue;
780 }
781
782 if (pending_obj == obj) {
783 // the thread is pending on this monitor so it isn't really owned
784 continue;
785 }
786
787 if (owned_monitors_list->length() > 0) {
788 // Our list has at least one object on it so we have to check
789 // for recursive object locking
790 bool found = false;
791 for (int j = 0; j < owned_monitors_list->length(); j++) {
792 jobject jobj = ((jvmtiMonitorStackDepthInfo*)owned_monitors_list->at(j))->monitor;
793 oop check = JNIHandles::resolve(jobj);
794 if (check == obj) {
795 found = true; // we found the object
796 break;
797 }
798 }
799
800 if (found) {
801 // already have this object so don't include it
802 continue;
803 }
804 }
805
806 // add the owning object to our list
807 jvmtiMonitorStackDepthInfo *jmsdi;
808 err = allocate(sizeof(jvmtiMonitorStackDepthInfo), (unsigned char **)&jmsdi);
809 if (err != JVMTI_ERROR_NONE) {
810 return err;
811 }
812 Handle hobj(Thread::current(), obj);
813 jmsdi->monitor = jni_reference(calling_thread, hobj);
814 jmsdi->stack_depth = stack_depth;
815 owned_monitors_list->append(jmsdi);
816 }
817
818 return err;
819 }
820
821 jvmtiError
822 JvmtiEnvBase::get_stack_trace(JavaThread *java_thread,
823 jint start_depth, jint max_count,
824 jvmtiFrameInfo* frame_buffer, jint* count_ptr) {
825 #ifdef ASSERT
826 uint32_t debug_bits = 0;
827 #endif
828 Thread *current_thread = Thread::current();
829 assert(SafepointSynchronize::is_at_safepoint() ||
830 java_thread->is_handshake_safe_for(current_thread),
831 "call by myself / at safepoint / at handshake");
832 int count = 0;
833 if (java_thread->has_last_Java_frame()) {
834 RegisterMap reg_map(java_thread, false /* update_map */, false /* process_frames */);
835 ResourceMark rm(current_thread);
836 javaVFrame *jvf = java_thread->last_java_vframe(®_map);
837 HandleMark hm(current_thread);
838 if (start_depth != 0) {
839 if (start_depth > 0) {
840 for (int j = 0; j < start_depth && jvf != NULL; j++) {
841 jvf = jvf->java_sender();
842 }
843 if (jvf == NULL) {
844 // start_depth is deeper than the stack depth
845 return JVMTI_ERROR_ILLEGAL_ARGUMENT;
846 }
847 } else { // start_depth < 0
848 // we are referencing the starting depth based on the oldest
849 // part of the stack.
850 // optimize to limit the number of times that java_sender() is called
851 javaVFrame *jvf_cursor = jvf;
852 javaVFrame *jvf_prev = NULL;
853 javaVFrame *jvf_prev_prev = NULL;
854 int j = 0;
855 while (jvf_cursor != NULL) {
856 jvf_prev_prev = jvf_prev;
857 jvf_prev = jvf_cursor;
858 for (j = 0; j > start_depth && jvf_cursor != NULL; j--) {
859 jvf_cursor = jvf_cursor->java_sender();
860 }
861 }
862 if (j == start_depth) {
863 // previous pointer is exactly where we want to start
864 jvf = jvf_prev;
865 } else {
866 // we need to back up further to get to the right place
867 if (jvf_prev_prev == NULL) {
868 // the -start_depth is greater than the stack depth
869 return JVMTI_ERROR_ILLEGAL_ARGUMENT;
870 }
871 // j now is the number of frames on the stack starting with
872 // jvf_prev, we start from jvf_prev_prev and move older on
873 // the stack that many, the result is -start_depth frames
874 // remaining.
875 jvf = jvf_prev_prev;
876 for (; j < 0; j++) {
877 jvf = jvf->java_sender();
878 }
879 }
880 }
881 }
882 for (; count < max_count && jvf != NULL; count++) {
883 frame_buffer[count].method = jvf->method()->jmethod_id();
884 frame_buffer[count].location = (jvf->method()->is_native() ? -1 : jvf->bci());
885 jvf = jvf->java_sender();
886 }
887 } else {
888 if (start_depth != 0) {
889 // no frames and there is a starting depth
890 return JVMTI_ERROR_ILLEGAL_ARGUMENT;
891 }
892 }
893 *count_ptr = count;
894 return JVMTI_ERROR_NONE;
895 }
896
897 jvmtiError
898 JvmtiEnvBase::get_frame_count(JvmtiThreadState *state, jint *count_ptr) {
899 assert((state != NULL),
900 "JavaThread should create JvmtiThreadState before calling this method");
901 *count_ptr = state->count_frames();
902 return JVMTI_ERROR_NONE;
903 }
904
905 jvmtiError
906 JvmtiEnvBase::get_frame_location(JavaThread *java_thread, jint depth,
907 jmethodID* method_ptr, jlocation* location_ptr) {
908 #ifdef ASSERT
909 uint32_t debug_bits = 0;
910 #endif
911 Thread* current_thread = Thread::current();
912 assert(java_thread->is_handshake_safe_for(current_thread),
913 "call by myself or at handshake");
914 ResourceMark rm(current_thread);
915
916 vframe *vf = vframeForNoProcess(java_thread, depth);
917 if (vf == NULL) {
918 return JVMTI_ERROR_NO_MORE_FRAMES;
919 }
920
921 // vframeFor should return a java frame. If it doesn't
922 // it means we've got an internal error and we return the
923 // error in product mode. In debug mode we will instead
924 // attempt to cast the vframe to a javaVFrame and will
925 // cause an assertion/crash to allow further diagnosis.
926 #ifdef PRODUCT
927 if (!vf->is_java_frame()) {
928 return JVMTI_ERROR_INTERNAL;
929 }
930 #endif
931
932 HandleMark hm(current_thread);
933 javaVFrame *jvf = javaVFrame::cast(vf);
934 Method* method = jvf->method();
935 if (method->is_native()) {
936 *location_ptr = -1;
937 } else {
938 *location_ptr = jvf->bci();
939 }
940 *method_ptr = method->jmethod_id();
941
942 return JVMTI_ERROR_NONE;
943 }
944
945
946 jvmtiError
947 JvmtiEnvBase::get_object_monitor_usage(JavaThread* calling_thread, jobject object, jvmtiMonitorUsage* info_ptr) {
948 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
949 Thread* current_thread = VMThread::vm_thread();
950 assert(current_thread == Thread::current(), "must be");
951
952 HandleMark hm(current_thread);
953 Handle hobj;
954
955 // Check arguments
956 {
957 oop mirror = JNIHandles::resolve_external_guard(object);
958 NULL_CHECK(mirror, JVMTI_ERROR_INVALID_OBJECT);
959 NULL_CHECK(info_ptr, JVMTI_ERROR_NULL_POINTER);
960
961 hobj = Handle(current_thread, mirror);
962 }
963
964 ThreadsListHandle tlh(current_thread);
965 JavaThread *owning_thread = NULL;
966 ObjectMonitor *mon = NULL;
967 jvmtiMonitorUsage ret = {
968 NULL, 0, 0, NULL, 0, NULL
969 };
970
971 uint32_t debug_bits = 0;
972 // first derive the object's owner and entry_count (if any)
973 {
974 // Revoke any biases before querying the mark word
975 BiasedLocking::revoke_at_safepoint(hobj);
976
977 address owner = NULL;
978 {
979 markWord mark = hobj()->mark();
980
981 if (!mark.has_monitor()) {
982 // this object has a lightweight monitor
983
984 if (mark.has_locker()) {
985 owner = (address)mark.locker(); // save the address of the Lock word
986 }
987 // implied else: no owner
988 } else {
989 // this object has a heavyweight monitor
990 mon = mark.monitor();
991
992 // The owner field of a heavyweight monitor may be NULL for no
993 // owner, a JavaThread * or it may still be the address of the
994 // Lock word in a JavaThread's stack. A monitor can be inflated
995 // by a non-owning JavaThread, but only the owning JavaThread
996 // can change the owner field from the Lock word to the
997 // JavaThread * and it may not have done that yet.
998 owner = (address)mon->owner();
999 }
1000 }
1001
1002 if (owner != NULL) {
1003 // This monitor is owned so we have to find the owning JavaThread.
1004 owning_thread = Threads::owning_thread_from_monitor_owner(tlh.list(), owner);
1005 assert(owning_thread != NULL, "owning JavaThread must not be NULL");
1006 Handle th(current_thread, owning_thread->threadObj());
1007 ret.owner = (jthread)jni_reference(calling_thread, th);
1008 }
1009
1010 if (owning_thread != NULL) { // monitor is owned
1011 // The recursions field of a monitor does not reflect recursions
1012 // as lightweight locks before inflating the monitor are not included.
1013 // We have to count the number of recursive monitor entries the hard way.
1014 // We pass a handle to survive any GCs along the way.
1015 ret.entry_count = count_locked_objects(owning_thread, hobj);
1016 }
1017 // implied else: entry_count == 0
1018 }
1019
1020 jint nWant = 0, nWait = 0;
1021 if (mon != NULL) {
1022 // this object has a heavyweight monitor
1023 nWant = mon->contentions(); // # of threads contending for monitor
1024 nWait = mon->waiters(); // # of threads in Object.wait()
1025 ret.waiter_count = nWant + nWait;
1026 ret.notify_waiter_count = nWait;
1027 } else {
1028 // this object has a lightweight monitor
1029 ret.waiter_count = 0;
1030 ret.notify_waiter_count = 0;
1031 }
1032
1033 // Allocate memory for heavyweight and lightweight monitor.
1034 jvmtiError err;
1035 err = allocate(ret.waiter_count * sizeof(jthread *), (unsigned char**)&ret.waiters);
1036 if (err != JVMTI_ERROR_NONE) {
1037 return err;
1038 }
1039 err = allocate(ret.notify_waiter_count * sizeof(jthread *),
1040 (unsigned char**)&ret.notify_waiters);
1041 if (err != JVMTI_ERROR_NONE) {
1042 deallocate((unsigned char*)ret.waiters);
1043 return err;
1044 }
1045
1046 // now derive the rest of the fields
1047 if (mon != NULL) {
1048 // this object has a heavyweight monitor
1049
1050 // Number of waiters may actually be less than the waiter count.
1051 // So NULL out memory so that unused memory will be NULL.
1052 memset(ret.waiters, 0, ret.waiter_count * sizeof(jthread *));
1053 memset(ret.notify_waiters, 0, ret.notify_waiter_count * sizeof(jthread *));
1054
1055 if (ret.waiter_count > 0) {
1056 // we have contending and/or waiting threads
1057 if (nWant > 0) {
1058 // we have contending threads
1059 ResourceMark rm(current_thread);
1060 // get_pending_threads returns only java thread so we do not need to
1061 // check for non java threads.
1062 GrowableArray<JavaThread*>* wantList = Threads::get_pending_threads(tlh.list(), nWant, (address)mon);
1063 if (wantList->length() < nWant) {
1064 // robustness: the pending list has gotten smaller
1065 nWant = wantList->length();
1066 }
1067 for (int i = 0; i < nWant; i++) {
1068 JavaThread *pending_thread = wantList->at(i);
1069 Handle th(current_thread, pending_thread->threadObj());
1070 ret.waiters[i] = (jthread)jni_reference(calling_thread, th);
1071 }
1072 }
1073 if (nWait > 0) {
1074 // we have threads in Object.wait()
1075 int offset = nWant; // add after any contending threads
1076 ObjectWaiter *waiter = mon->first_waiter();
1077 for (int i = 0, j = 0; i < nWait; i++) {
1078 if (waiter == NULL) {
1079 // robustness: the waiting list has gotten smaller
1080 nWait = j;
1081 break;
1082 }
1083 JavaThread *w = mon->thread_of_waiter(waiter);
1084 if (w != NULL) {
1085 // If the thread was found on the ObjectWaiter list, then
1086 // it has not been notified. This thread can't change the
1087 // state of the monitor so it doesn't need to be suspended.
1088 Handle th(current_thread, w->threadObj());
1089 ret.waiters[offset + j] = (jthread)jni_reference(calling_thread, th);
1090 ret.notify_waiters[j++] = (jthread)jni_reference(calling_thread, th);
1091 }
1092 waiter = mon->next_waiter(waiter);
1093 }
1094 }
1095 } // ThreadsListHandle is destroyed here.
1096
1097 // Adjust count. nWant and nWait count values may be less than original.
1098 ret.waiter_count = nWant + nWait;
1099 ret.notify_waiter_count = nWait;
1100 } else {
1101 // this object has a lightweight monitor and we have nothing more
1102 // to do here because the defaults are just fine.
1103 }
1104
1105 // we don't update return parameter unless everything worked
1106 *info_ptr = ret;
1107
1108 return JVMTI_ERROR_NONE;
1109 }
1110
1111 ResourceTracker::ResourceTracker(JvmtiEnv* env) {
1112 _env = env;
1113 _allocations = new (ResourceObj::C_HEAP, mtServiceability) GrowableArray<unsigned char*>(20, mtServiceability);
1114 _failed = false;
1115 }
1116 ResourceTracker::~ResourceTracker() {
1117 if (_failed) {
1118 for (int i=0; i<_allocations->length(); i++) {
1119 _env->deallocate(_allocations->at(i));
1120 }
1121 }
1122 delete _allocations;
1123 }
1124
1125 jvmtiError ResourceTracker::allocate(jlong size, unsigned char** mem_ptr) {
1126 unsigned char *ptr;
1127 jvmtiError err = _env->allocate(size, &ptr);
1128 if (err == JVMTI_ERROR_NONE) {
1129 _allocations->append(ptr);
1130 *mem_ptr = ptr;
1131 } else {
1132 *mem_ptr = NULL;
1133 _failed = true;
1134 }
1135 return err;
1136 }
1137
1138 unsigned char* ResourceTracker::allocate(jlong size) {
1139 unsigned char* ptr;
1140 allocate(size, &ptr);
1141 return ptr;
1142 }
1143
1144 char* ResourceTracker::strdup(const char* str) {
1145 char *dup_str = (char*)allocate(strlen(str)+1);
1146 if (dup_str != NULL) {
1147 strcpy(dup_str, str);
1148 }
1149 return dup_str;
1150 }
1151
1152 struct StackInfoNode {
1153 struct StackInfoNode *next;
1154 jvmtiStackInfo info;
1155 };
1156
1157 // Create a jvmtiStackInfo inside a linked list node and create a
1158 // buffer for the frame information, both allocated as resource objects.
1159 // Fill in both the jvmtiStackInfo and the jvmtiFrameInfo.
1160 // Note that either or both of thr and thread_oop
1161 // may be null if the thread is new or has exited.
1162 void
1163 MultipleStackTracesCollector::fill_frames(jthread jt, JavaThread *thr, oop thread_oop) {
1164 #ifdef ASSERT
1165 Thread *current_thread = Thread::current();
1166 assert(SafepointSynchronize::is_at_safepoint() ||
1167 thr->is_handshake_safe_for(current_thread),
1168 "call by myself / at safepoint / at handshake");
1169 #endif
1170
1171 jint state = 0;
1172 struct StackInfoNode *node = NEW_RESOURCE_OBJ(struct StackInfoNode);
1173 jvmtiStackInfo *infop = &(node->info);
1174 node->next = head();
1175 set_head(node);
1176 infop->frame_count = 0;
1177 infop->thread = jt;
1178
1179 if (thread_oop != NULL) {
1180 // get most state bits
1181 state = (jint)java_lang_Thread::get_thread_status(thread_oop);
1182 }
1183
1184 if (thr != NULL) { // add more state bits if there is a JavaThead to query
1185 if (thr->is_suspended()) {
1186 state |= JVMTI_THREAD_STATE_SUSPENDED;
1187 }
1188 JavaThreadState jts = thr->thread_state();
1189 if (jts == _thread_in_native) {
1190 state |= JVMTI_THREAD_STATE_IN_NATIVE;
1191 }
1192 if (thr->is_interrupted(false)) {
1193 state |= JVMTI_THREAD_STATE_INTERRUPTED;
1194 }
1195 }
1196 infop->state = state;
1197
1198 if (thr != NULL && (state & JVMTI_THREAD_STATE_ALIVE) != 0) {
1199 infop->frame_buffer = NEW_RESOURCE_ARRAY(jvmtiFrameInfo, max_frame_count());
1200 env()->get_stack_trace(thr, 0, max_frame_count(),
1201 infop->frame_buffer, &(infop->frame_count));
1202 } else {
1203 infop->frame_buffer = NULL;
1204 infop->frame_count = 0;
1205 }
1206 _frame_count_total += infop->frame_count;
1207 }
1208
1209 // Based on the stack information in the linked list, allocate memory
1210 // block to return and fill it from the info in the linked list.
1211 void
1212 MultipleStackTracesCollector::allocate_and_fill_stacks(jint thread_count) {
1213 // do I need to worry about alignment issues?
1214 jlong alloc_size = thread_count * sizeof(jvmtiStackInfo)
1215 + _frame_count_total * sizeof(jvmtiFrameInfo);
1216 env()->allocate(alloc_size, (unsigned char **)&_stack_info);
1217
1218 // pointers to move through the newly allocated space as it is filled in
1219 jvmtiStackInfo *si = _stack_info + thread_count; // bottom of stack info
1220 jvmtiFrameInfo *fi = (jvmtiFrameInfo *)si; // is the top of frame info
1221
1222 // copy information in resource area into allocated buffer
1223 // insert stack info backwards since linked list is backwards
1224 // insert frame info forwards
1225 // walk the StackInfoNodes
1226 for (struct StackInfoNode *sin = head(); sin != NULL; sin = sin->next) {
1227 jint frame_count = sin->info.frame_count;
1228 size_t frames_size = frame_count * sizeof(jvmtiFrameInfo);
1229 --si;
1230 memcpy(si, &(sin->info), sizeof(jvmtiStackInfo));
1231 if (frames_size == 0) {
1232 si->frame_buffer = NULL;
1233 } else {
1234 memcpy(fi, sin->info.frame_buffer, frames_size);
1235 si->frame_buffer = fi; // point to the new allocated copy of the frames
1236 fi += frame_count;
1237 }
1238 }
1239 assert(si == _stack_info, "the last copied stack info must be the first record");
1240 assert((unsigned char *)fi == ((unsigned char *)_stack_info) + alloc_size,
1241 "the last copied frame info must be the last record");
1242 }
1243
1244
1245 void
1246 VM_GetThreadListStackTraces::doit() {
1247 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
1248
1249 ResourceMark rm;
1250 ThreadsListHandle tlh;
1251 for (int i = 0; i < _thread_count; ++i) {
1252 jthread jt = _thread_list[i];
1253 JavaThread* java_thread = NULL;
1254 oop thread_oop = NULL;
1255 jvmtiError err = JvmtiExport::cv_external_thread_to_JavaThread(tlh.list(), jt, &java_thread, &thread_oop);
1256 if (err != JVMTI_ERROR_NONE) {
1257 // We got an error code so we don't have a JavaThread *, but
1258 // only return an error from here if we didn't get a valid
1259 // thread_oop.
1260 if (thread_oop == NULL) {
1261 _collector.set_result(err);
1262 return;
1263 }
1264 // We have a valid thread_oop.
1265 }
1266 _collector.fill_frames(jt, java_thread, thread_oop);
1267 }
1268 _collector.allocate_and_fill_stacks(_thread_count);
1269 }
1270
1271 void
1272 GetSingleStackTraceClosure::do_thread(Thread *target) {
1273 JavaThread *jt = target->as_Java_thread();
1274 oop thread_oop = jt->threadObj();
1275
1276 if (!jt->is_exiting() && thread_oop != NULL) {
1277 ResourceMark rm;
1278 _collector.fill_frames(_jthread, jt, thread_oop);
1279 _collector.allocate_and_fill_stacks(1);
1280 }
1281 }
1282
1283 void
1284 VM_GetAllStackTraces::doit() {
1285 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
1286
1287 ResourceMark rm;
1288 _final_thread_count = 0;
1289 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *jt = jtiwh.next(); ) {
1290 oop thread_oop = jt->threadObj();
1291 if (thread_oop != NULL &&
1292 !jt->is_exiting() &&
1293 java_lang_Thread::is_alive(thread_oop) &&
1294 !jt->is_hidden_from_external_view()) {
1295 ++_final_thread_count;
1296 // Handle block of the calling thread is used to create local refs.
1297 _collector.fill_frames((jthread)JNIHandles::make_local(_calling_thread, thread_oop),
1298 jt, thread_oop);
1299 }
1300 }
1301 _collector.allocate_and_fill_stacks(_final_thread_count);
1302 }
1303
1304 // Verifies that the top frame is a java frame in an expected state.
1305 // Deoptimizes frame if needed.
1306 // Checks that the frame method signature matches the return type (tos).
1307 // HandleMark must be defined in the caller only.
1308 // It is to keep a ret_ob_h handle alive after return to the caller.
1309 jvmtiError
1310 JvmtiEnvBase::check_top_frame(Thread* current_thread, JavaThread* java_thread,
1311 jvalue value, TosState tos, Handle* ret_ob_h) {
1312 ResourceMark rm(current_thread);
1313
1314 vframe *vf = vframeForNoProcess(java_thread, 0);
1315 NULL_CHECK(vf, JVMTI_ERROR_NO_MORE_FRAMES);
1316
1317 javaVFrame *jvf = (javaVFrame*) vf;
1318 if (!vf->is_java_frame() || jvf->method()->is_native()) {
1319 return JVMTI_ERROR_OPAQUE_FRAME;
1320 }
1321
1322 // If the frame is a compiled one, need to deoptimize it.
1323 if (vf->is_compiled_frame()) {
1324 if (!vf->fr().can_be_deoptimized()) {
1325 return JVMTI_ERROR_OPAQUE_FRAME;
1326 }
1327 Deoptimization::deoptimize_frame(java_thread, jvf->fr().id());
1328 }
1329
1330 // Get information about method return type
1331 Symbol* signature = jvf->method()->signature();
1332
1333 ResultTypeFinder rtf(signature);
1334 TosState fr_tos = as_TosState(rtf.type());
1335 if (fr_tos != tos) {
1336 if (tos != itos || (fr_tos != btos && fr_tos != ztos && fr_tos != ctos && fr_tos != stos)) {
1337 return JVMTI_ERROR_TYPE_MISMATCH;
1338 }
1339 }
1340
1341 // Check that the jobject class matches the return type signature.
1342 jobject jobj = value.l;
1343 if (tos == atos && jobj != NULL) { // NULL reference is allowed
1344 Handle ob_h(current_thread, JNIHandles::resolve_external_guard(jobj));
1345 NULL_CHECK(ob_h, JVMTI_ERROR_INVALID_OBJECT);
1346 Klass* ob_k = ob_h()->klass();
1347 NULL_CHECK(ob_k, JVMTI_ERROR_INVALID_OBJECT);
1348
1349 // Method return type signature.
1350 char* ty_sign = 1 + strchr(signature->as_C_string(), JVM_SIGNATURE_ENDFUNC);
1351
1352 if (!VM_GetOrSetLocal::is_assignable(ty_sign, ob_k, current_thread)) {
1353 return JVMTI_ERROR_TYPE_MISMATCH;
1354 }
1355 *ret_ob_h = ob_h;
1356 }
1357 return JVMTI_ERROR_NONE;
1358 } /* end check_top_frame */
1359
1360
1361 // ForceEarlyReturn<type> follows the PopFrame approach in many aspects.
1362 // Main difference is on the last stage in the interpreter.
1363 // The PopFrame stops method execution to continue execution
1364 // from the same method call instruction.
1365 // The ForceEarlyReturn forces return from method so the execution
1366 // continues at the bytecode following the method call.
1367
1368 // java_thread - protected by ThreadsListHandle and pre-checked
1369
1370 jvmtiError
1371 JvmtiEnvBase::force_early_return(JavaThread* java_thread, jvalue value, TosState tos) {
1372 // retrieve or create the state
1373 JvmtiThreadState* state = JvmtiThreadState::state_for(java_thread);
1374 if (state == NULL) {
1375 return JVMTI_ERROR_THREAD_NOT_ALIVE;
1376 }
1377
1378 // Eagerly reallocate scalar replaced objects.
1379 JavaThread* current_thread = JavaThread::current();
1380 EscapeBarrier eb(true, current_thread, java_thread);
1381 if (!eb.deoptimize_objects(0)) {
1382 // Reallocation of scalar replaced objects failed -> return with error
1383 return JVMTI_ERROR_OUT_OF_MEMORY;
1384 }
1385
1386 SetForceEarlyReturn op(state, value, tos);
1387 if (java_thread == current_thread) {
1388 op.doit(java_thread, true /* self */);
1389 } else {
1390 Handshake::execute(&op, java_thread);
1391 }
1392 return op.result();
1393 }
1394
1395 void
1396 SetForceEarlyReturn::doit(Thread *target, bool self) {
1397 JavaThread* java_thread = target->as_Java_thread();
1398 Thread* current_thread = Thread::current();
1399 HandleMark hm(current_thread);
1400
1401 if (java_thread->is_exiting()) {
1402 return; /* JVMTI_ERROR_THREAD_NOT_ALIVE (default) */
1403 }
1404 if (!self) {
1405 if (!java_thread->is_suspended()) {
1406 _result = JVMTI_ERROR_THREAD_NOT_SUSPENDED;
1407 return;
1408 }
1409 }
1410
1411 // Check to see if a ForceEarlyReturn was already in progress
1412 if (_state->is_earlyret_pending()) {
1413 // Probably possible for JVMTI clients to trigger this, but the
1414 // JPDA backend shouldn't allow this to happen
1415 _result = JVMTI_ERROR_INTERNAL;
1416 return;
1417 }
1418 {
1419 // The same as for PopFrame. Workaround bug:
1420 // 4812902: popFrame hangs if the method is waiting at a synchronize
1421 // Catch this condition and return an error to avoid hanging.
1422 // Now JVMTI spec allows an implementation to bail out with an opaque
1423 // frame error.
1424 OSThread* osThread = java_thread->osthread();
1425 if (osThread->get_state() == MONITOR_WAIT) {
1426 _result = JVMTI_ERROR_OPAQUE_FRAME;
1427 return;
1428 }
1429 }
1430
1431 Handle ret_ob_h;
1432 _result = JvmtiEnvBase::check_top_frame(current_thread, java_thread, _value, _tos, &ret_ob_h);
1433 if (_result != JVMTI_ERROR_NONE) {
1434 return;
1435 }
1436 assert(_tos != atos || _value.l == NULL || ret_ob_h() != NULL,
1437 "return object oop must not be NULL if jobject is not NULL");
1438
1439 // Update the thread state to reflect that the top frame must be
1440 // forced to return.
1441 // The current frame will be returned later when the suspended
1442 // thread is resumed and right before returning from VM to Java.
1443 // (see call_VM_base() in assembler_<cpu>.cpp).
1444
1445 _state->set_earlyret_pending();
1446 _state->set_earlyret_oop(ret_ob_h());
1447 _state->set_earlyret_value(_value, _tos);
1448
1449 // Set pending step flag for this early return.
1450 // It is cleared when next step event is posted.
1451 _state->set_pending_step_for_earlyret();
1452 }
1453
1454 void
1455 JvmtiMonitorClosure::do_monitor(ObjectMonitor* mon) {
1456 if ( _error != JVMTI_ERROR_NONE) {
1457 // Error occurred in previous iteration so no need to add
1458 // to the list.
1459 return;
1460 }
1461 // Filter out on stack monitors collected during stack walk.
1462 oop obj = mon->object();
1463 bool found = false;
1464 for (int j = 0; j < _owned_monitors_list->length(); j++) {
1465 jobject jobj = ((jvmtiMonitorStackDepthInfo*)_owned_monitors_list->at(j))->monitor;
1466 oop check = JNIHandles::resolve(jobj);
1467 if (check == obj) {
1468 // On stack monitor already collected during the stack walk.
1469 found = true;
1470 break;
1471 }
1472 }
1473 if (found == false) {
1474 // This is off stack monitor (e.g. acquired via jni MonitorEnter).
1475 jvmtiError err;
1476 jvmtiMonitorStackDepthInfo *jmsdi;
1477 err = _env->allocate(sizeof(jvmtiMonitorStackDepthInfo), (unsigned char **)&jmsdi);
1478 if (err != JVMTI_ERROR_NONE) {
1479 _error = err;
1480 return;
1481 }
1482 Handle hobj(Thread::current(), obj);
1483 jmsdi->monitor = _env->jni_reference(_calling_thread, hobj);
1484 // stack depth is unknown for this monitor.
1485 jmsdi->stack_depth = -1;
1486 _owned_monitors_list->append(jmsdi);
1487 }
1488 }
1489
1490 GrowableArray<OopHandle>* JvmtiModuleClosure::_tbl = NULL;
1491
1492 void JvmtiModuleClosure::do_module(ModuleEntry* entry) {
1493 assert_locked_or_safepoint(Module_lock);
1494 OopHandle module = entry->module_handle();
1495 guarantee(module.resolve() != NULL, "module object is NULL");
1496 _tbl->push(module);
1497 }
1498
1499 jvmtiError
1500 JvmtiModuleClosure::get_all_modules(JvmtiEnv* env, jint* module_count_ptr, jobject** modules_ptr) {
1501 ResourceMark rm;
1502 MutexLocker mcld(ClassLoaderDataGraph_lock);
1503 MutexLocker ml(Module_lock);
1504
1505 _tbl = new GrowableArray<OopHandle>(77);
1506 if (_tbl == NULL) {
1507 return JVMTI_ERROR_OUT_OF_MEMORY;
1508 }
1509
1510 // Iterate over all the modules loaded to the system.
1511 ClassLoaderDataGraph::modules_do(&do_module);
1512
1513 jint len = _tbl->length();
1514 guarantee(len > 0, "at least one module must be present");
1515
1516 jobject* array = (jobject*)env->jvmtiMalloc((jlong)(len * sizeof(jobject)));
1517 if (array == NULL) {
1518 return JVMTI_ERROR_OUT_OF_MEMORY;
1519 }
1520 for (jint idx = 0; idx < len; idx++) {
1521 array[idx] = JNIHandles::make_local(Thread::current(), _tbl->at(idx).resolve());
1522 }
1523 _tbl = NULL;
1524 *modules_ptr = array;
1525 *module_count_ptr = len;
1526 return JVMTI_ERROR_NONE;
1527 }
1528
1529 void
1530 UpdateForPopTopFrameClosure::doit(Thread *target, bool self) {
1531 Thread* current_thread = Thread::current();
1532 HandleMark hm(current_thread);
1533 JavaThread* java_thread = target->as_Java_thread();
1534
1535 if (java_thread->is_exiting()) {
1536 return; /* JVMTI_ERROR_THREAD_NOT_ALIVE (default) */
1537 }
1538 assert(java_thread == _state->get_thread(), "Must be");
1539
1540 if (!self && !java_thread->is_suspended()) {
1541 _result = JVMTI_ERROR_THREAD_NOT_SUSPENDED;
1542 return;
1543 }
1544
1545 // Check to see if a PopFrame was already in progress
1546 if (java_thread->popframe_condition() != JavaThread::popframe_inactive) {
1547 // Probably possible for JVMTI clients to trigger this, but the
1548 // JPDA backend shouldn't allow this to happen
1549 _result = JVMTI_ERROR_INTERNAL;
1550 return;
1551 }
1552
1553 // Was workaround bug
1554 // 4812902: popFrame hangs if the method is waiting at a synchronize
1555 // Catch this condition and return an error to avoid hanging.
1556 // Now JVMTI spec allows an implementation to bail out with an opaque frame error.
1557 OSThread* osThread = java_thread->osthread();
1558 if (osThread->get_state() == MONITOR_WAIT) {
1559 _result = JVMTI_ERROR_OPAQUE_FRAME;
1560 return;
1561 }
1562
1563 ResourceMark rm(current_thread);
1564 // Check if there is more than one Java frame in this thread, that the top two frames
1565 // are Java (not native) frames, and that there is no intervening VM frame
1566 int frame_count = 0;
1567 bool is_interpreted[2];
1568 intptr_t *frame_sp[2];
1569 // The 2-nd arg of constructor is needed to stop iterating at java entry frame.
1570 for (vframeStream vfs(java_thread, true, false /* process_frames */); !vfs.at_end(); vfs.next()) {
1571 methodHandle mh(current_thread, vfs.method());
1572 if (mh->is_native()) {
1573 _result = JVMTI_ERROR_OPAQUE_FRAME;
1574 return;
1575 }
1576 is_interpreted[frame_count] = vfs.is_interpreted_frame();
1577 frame_sp[frame_count] = vfs.frame_id();
1578 if (++frame_count > 1) break;
1579 }
1580 if (frame_count < 2) {
1581 // We haven't found two adjacent non-native Java frames on the top.
1582 // There can be two situations here:
1583 // 1. There are no more java frames
1584 // 2. Two top java frames are separated by non-java native frames
1585 if(JvmtiEnvBase::vframeForNoProcess(java_thread, 1) == NULL) {
1586 _result = JVMTI_ERROR_NO_MORE_FRAMES;
1587 return;
1588 } else {
1589 // Intervening non-java native or VM frames separate java frames.
1590 // Current implementation does not support this. See bug #5031735.
1591 // In theory it is possible to pop frames in such cases.
1592 _result = JVMTI_ERROR_OPAQUE_FRAME;
1593 return;
1594 }
1595 }
1596
1597 // If any of the top 2 frames is a compiled one, need to deoptimize it
1598 for (int i = 0; i < 2; i++) {
1599 if (!is_interpreted[i]) {
1600 Deoptimization::deoptimize_frame(java_thread, frame_sp[i]);
1601 }
1602 }
1603
1604 // Update the thread state to reflect that the top frame is popped
1605 // so that cur_stack_depth is maintained properly and all frameIDs
1606 // are invalidated.
1607 // The current frame will be popped later when the suspended thread
1608 // is resumed and right before returning from VM to Java.
1609 // (see call_VM_base() in assembler_<cpu>.cpp).
1610
1611 // It's fine to update the thread state here because no JVMTI events
1612 // shall be posted for this PopFrame.
1613
1614 _state->update_for_pop_top_frame();
1615 java_thread->set_popframe_condition(JavaThread::popframe_pending_bit);
1616 // Set pending step flag for this popframe and it is cleared when next
1617 // step event is posted.
1618 _state->set_pending_step_for_popframe();
1619 _result = JVMTI_ERROR_NONE;
1620 }
1621
1622 void
1623 SetFramePopClosure::doit(Thread *target, bool self) {
1624 ResourceMark rm;
1625 JavaThread* java_thread = target->as_Java_thread();
1626
1627 if (java_thread->is_exiting()) {
1628 return; /* JVMTI_ERROR_THREAD_NOT_ALIVE (default) */
1629 }
1630 assert(_state->get_thread() == java_thread, "Must be");
1631
1632 if (!self && !java_thread->is_suspended()) {
1633 _result = JVMTI_ERROR_THREAD_NOT_SUSPENDED;
1634 return;
1635 }
1636
1637 vframe *vf = JvmtiEnvBase::vframeForNoProcess(java_thread, _depth);
1638 if (vf == NULL) {
1639 _result = JVMTI_ERROR_NO_MORE_FRAMES;
1640 return;
1641 }
1642
1643 if (!vf->is_java_frame() || ((javaVFrame*) vf)->method()->is_native()) {
1644 _result = JVMTI_ERROR_OPAQUE_FRAME;
1645 return;
1646 }
1647
1648 assert(vf->frame_pointer() != NULL, "frame pointer mustn't be NULL");
1649 int frame_number = _state->count_frames() - _depth;
1650 _state->env_thread_state((JvmtiEnvBase*)_env)->set_frame_pop(frame_number);
1651 _result = JVMTI_ERROR_NONE;
1652 }
1653
1654 void
1655 GetOwnedMonitorInfoClosure::do_thread(Thread *target) {
1656 JavaThread *jt = target->as_Java_thread();
1657 if (!jt->is_exiting() && (jt->threadObj() != NULL)) {
1658 _result = ((JvmtiEnvBase *)_env)->get_owned_monitors(_calling_thread,
1659 jt,
1660 _owned_monitors_list);
1661 }
1662 }
1663
1664 void
1665 GetCurrentContendedMonitorClosure::do_thread(Thread *target) {
1666 JavaThread *jt = target->as_Java_thread();
1667 if (!jt->is_exiting() && (jt->threadObj() != NULL)) {
1668 _result = ((JvmtiEnvBase *)_env)->get_current_contended_monitor(_calling_thread,
1669 jt,
1670 _owned_monitor_ptr);
1671 }
1672 }
1673
1674 void
1675 GetStackTraceClosure::do_thread(Thread *target) {
1676 JavaThread *jt = target->as_Java_thread();
1677 if (!jt->is_exiting() && jt->threadObj() != NULL) {
1678 _result = ((JvmtiEnvBase *)_env)->get_stack_trace(jt,
1679 _start_depth, _max_count,
1680 _frame_buffer, _count_ptr);
1681 }
1682 }
1683
1684 void
1685 GetFrameCountClosure::do_thread(Thread *target) {
1686 JavaThread* jt = _state->get_thread();
1687 assert(target == jt, "just checking");
1688 if (!jt->is_exiting() && jt->threadObj() != NULL) {
1689 _result = ((JvmtiEnvBase*)_env)->get_frame_count(_state, _count_ptr);
1690 }
1691 }
1692
1693 void
1694 GetFrameLocationClosure::do_thread(Thread *target) {
1695 JavaThread *jt = target->as_Java_thread();
1696 if (!jt->is_exiting() && jt->threadObj() != NULL) {
1697 _result = ((JvmtiEnvBase*)_env)->get_frame_location(jt, _depth,
1698 _method_ptr, _location_ptr);
1699 }
1700 }