1 /*
2 * Copyright (c) 2003, 2014, 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/systemDictionary.hpp"
27 #include "jvmtifiles/jvmtiEnv.hpp"
28 #include "oops/objArrayKlass.hpp"
29 #include "oops/objArrayOop.hpp"
30 #include "prims/jvmtiEnvBase.hpp"
31 #include "prims/jvmtiEventController.inline.hpp"
32 #include "prims/jvmtiExtensions.hpp"
33 #include "prims/jvmtiImpl.hpp"
34 #include "prims/jvmtiManageCapabilities.hpp"
35 #include "prims/jvmtiTagMap.hpp"
36 #include "prims/jvmtiThreadState.inline.hpp"
37 #include "runtime/biasedLocking.hpp"
38 #include "runtime/deoptimization.hpp"
39 #include "runtime/interfaceSupport.hpp"
40 #include "runtime/jfieldIDWorkaround.hpp"
41 #include "runtime/objectMonitor.hpp"
42 #include "runtime/objectMonitor.inline.hpp"
43 #include "runtime/signature.hpp"
44 #include "runtime/thread.inline.hpp"
45 #include "runtime/vframe.hpp"
46 #include "runtime/vframe_hp.hpp"
47 #include "runtime/vmThread.hpp"
48 #include "runtime/vm_operations.hpp"
49
50 ///////////////////////////////////////////////////////////////
51 //
52 // JvmtiEnvBase
53 //
54
55 JvmtiEnvBase* JvmtiEnvBase::_head_environment = NULL;
56
57 bool JvmtiEnvBase::_globally_initialized = false;
58 volatile bool JvmtiEnvBase::_needs_clean_up = false;
59
60 jvmtiPhase JvmtiEnvBase::_phase = JVMTI_PHASE_PRIMORDIAL;
61
62 volatile int JvmtiEnvBase::_dying_thread_env_iteration_count = 0;
63
64 extern jvmtiInterface_1_ jvmti_Interface;
65 extern jvmtiInterface_1_ jvmtiTrace_Interface;
66
67
68 // perform initializations that must occur before any JVMTI environments
69 // are released but which should only be initialized once (no matter
70 // how many environments are created).
71 void
72 JvmtiEnvBase::globally_initialize() {
73 assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(), "sanity check");
74 assert(_globally_initialized == false, "bad call");
75
76 JvmtiManageCapabilities::initialize();
77
78 // register extension functions and events
79 JvmtiExtensions::register_extensions();
80
81 #ifdef JVMTI_TRACE
82 JvmtiTrace::initialize();
83 #endif
84
85 _globally_initialized = true;
86 }
87
88
89 void
90 JvmtiEnvBase::initialize() {
91 assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(), "sanity check");
92
93 // Add this environment to the end of the environment list (order is important)
94 {
95 // This block of code must not contain any safepoints, as list deallocation
96 // (which occurs at a safepoint) cannot occur simultaneously with this list
97 // addition. Note: No_Safepoint_Verifier cannot, currently, be used before
98 // threads exist.
99 JvmtiEnvIterator it;
100 JvmtiEnvBase *previous_env = NULL;
101 for (JvmtiEnvBase* env = it.first(); env != NULL; env = it.next(env)) {
102 previous_env = env;
103 }
104 if (previous_env == NULL) {
105 _head_environment = this;
106 } else {
107 previous_env->set_next_environment(this);
108 }
109 }
110
111 if (_globally_initialized == false) {
112 globally_initialize();
113 }
114 }
115
116
117 bool
118 JvmtiEnvBase::is_valid() {
119 jint value = 0;
120
121 // This object might not be a JvmtiEnvBase so we can't assume
122 // the _magic field is properly aligned. Get the value in a safe
123 // way and then check against JVMTI_MAGIC.
124
125 switch (sizeof(_magic)) {
126 case 2:
127 value = Bytes::get_native_u2((address)&_magic);
128 break;
129
130 case 4:
131 value = Bytes::get_native_u4((address)&_magic);
132 break;
133
134 case 8:
135 value = Bytes::get_native_u8((address)&_magic);
136 break;
137
138 default:
139 guarantee(false, "_magic field is an unexpected size");
140 }
141
142 return value == JVMTI_MAGIC;
143 }
144
145
146 bool
147 JvmtiEnvBase::use_version_1_0_semantics() {
148 int major, minor, micro;
149
150 JvmtiExport::decode_version_values(_version, &major, &minor, µ);
151 return major == 1 && minor == 0; // micro version doesn't matter here
152 }
153
154
155 bool
156 JvmtiEnvBase::use_version_1_1_semantics() {
157 int major, minor, micro;
158
159 JvmtiExport::decode_version_values(_version, &major, &minor, µ);
160 return major == 1 && minor == 1; // micro version doesn't matter here
161 }
162
163 bool
164 JvmtiEnvBase::use_version_1_2_semantics() {
165 int major, minor, micro;
166
167 JvmtiExport::decode_version_values(_version, &major, &minor, µ);
168 return major == 1 && minor == 2; // micro version doesn't matter here
169 }
170
171
172 JvmtiEnvBase::JvmtiEnvBase(jint version) : _env_event_enable() {
173 _version = version;
174 _env_local_storage = NULL;
175 _tag_map = NULL;
176 _native_method_prefix_count = 0;
177 _native_method_prefixes = NULL;
178 _next = NULL;
179 _class_file_load_hook_ever_enabled = false;
180
181 // Moot since ClassFileLoadHook not yet enabled.
182 // But "true" will give a more predictable ClassFileLoadHook behavior
183 // for environment creation during ClassFileLoadHook.
184 _is_retransformable = true;
185
186 // all callbacks initially NULL
187 memset(&_event_callbacks,0,sizeof(jvmtiEventCallbacks));
188
189 // all capabilities initially off
190 memset(&_current_capabilities, 0, sizeof(_current_capabilities));
191
192 // all prohibited capabilities initially off
193 memset(&_prohibited_capabilities, 0, sizeof(_prohibited_capabilities));
194
195 _magic = JVMTI_MAGIC;
196
197 JvmtiEventController::env_initialize((JvmtiEnv*)this);
198
199 #ifdef JVMTI_TRACE
200 _jvmti_external.functions = TraceJVMTI != NULL ? &jvmtiTrace_Interface : &jvmti_Interface;
201 #else
202 _jvmti_external.functions = &jvmti_Interface;
203 #endif
204 }
205
206
207 void
208 JvmtiEnvBase::dispose() {
209
210 #ifdef JVMTI_TRACE
211 JvmtiTrace::shutdown();
212 #endif
213
214 // Dispose of event info and let the event controller call us back
215 // in a locked state (env_dispose, below)
216 JvmtiEventController::env_dispose(this);
217 }
218
219 void
220 JvmtiEnvBase::env_dispose() {
221 assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(), "sanity check");
222
223 // We have been entered with all events disabled on this environment.
224 // A race to re-enable events (by setting callbacks) is prevented by
225 // checking for a valid environment when setting callbacks (while
226 // holding the JvmtiThreadState_lock).
227
228 // Mark as invalid.
229 _magic = DISPOSED_MAGIC;
230
231 // Relinquish all capabilities.
232 jvmtiCapabilities *caps = get_capabilities();
233 JvmtiManageCapabilities::relinquish_capabilities(caps, caps, caps);
234
235 // Same situation as with events (see above)
236 set_native_method_prefixes(0, NULL);
237
238 JvmtiTagMap* tag_map_to_deallocate = _tag_map;
239 set_tag_map(NULL);
240 // A tag map can be big, deallocate it now
241 if (tag_map_to_deallocate != NULL) {
242 delete tag_map_to_deallocate;
243 }
244
245 _needs_clean_up = true;
246 }
247
248
249 JvmtiEnvBase::~JvmtiEnvBase() {
250 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
251
252 // There is a small window of time during which the tag map of a
253 // disposed environment could have been reallocated.
254 // Make sure it is gone.
255 JvmtiTagMap* tag_map_to_deallocate = _tag_map;
256 set_tag_map(NULL);
257 // A tag map can be big, deallocate it now
258 if (tag_map_to_deallocate != NULL) {
259 delete tag_map_to_deallocate;
260 }
261
262 _magic = BAD_MAGIC;
263 }
264
265
266 void
267 JvmtiEnvBase::periodic_clean_up() {
268 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
269
270 // JvmtiEnvBase reference is saved in JvmtiEnvThreadState. So
271 // clean up JvmtiThreadState before deleting JvmtiEnv pointer.
272 JvmtiThreadState::periodic_clean_up();
273
274 // Unlink all invalid environments from the list of environments
275 // and deallocate them
276 JvmtiEnvIterator it;
277 JvmtiEnvBase* previous_env = NULL;
278 JvmtiEnvBase* env = it.first();
279 while (env != NULL) {
280 if (env->is_valid()) {
281 previous_env = env;
282 env = it.next(env);
283 } else {
284 // This one isn't valid, remove it from the list and deallocate it
285 JvmtiEnvBase* defunct_env = env;
286 env = it.next(env);
287 if (previous_env == NULL) {
288 _head_environment = env;
289 } else {
290 previous_env->set_next_environment(env);
291 }
292 delete defunct_env;
293 }
294 }
295
296 }
297
298
299 void
300 JvmtiEnvBase::check_for_periodic_clean_up() {
301 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
302
303 class ThreadInsideIterationClosure: public ThreadClosure {
304 private:
305 bool _inside;
306 public:
307 ThreadInsideIterationClosure() : _inside(false) {};
308
309 void do_thread(Thread* thread) {
310 _inside |= thread->is_inside_jvmti_env_iteration();
311 }
312
313 bool is_inside_jvmti_env_iteration() {
314 return _inside;
315 }
316 };
317
318 if (_needs_clean_up) {
319 // Check if we are currently iterating environment,
320 // deallocation should not occur if we are
321 ThreadInsideIterationClosure tiic;
322 Threads::threads_do(&tiic);
323 if (!tiic.is_inside_jvmti_env_iteration() &&
324 !is_inside_dying_thread_env_iteration()) {
325 _needs_clean_up = false;
326 JvmtiEnvBase::periodic_clean_up();
327 }
328 }
329 }
330
331
332 void
333 JvmtiEnvBase::record_first_time_class_file_load_hook_enabled() {
334 assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(),
335 "sanity check");
336
337 if (!_class_file_load_hook_ever_enabled) {
338 _class_file_load_hook_ever_enabled = true;
339
340 if (get_capabilities()->can_retransform_classes) {
341 _is_retransformable = true;
342 } else {
343 _is_retransformable = false;
344
345 // cannot add retransform capability after ClassFileLoadHook has been enabled
346 get_prohibited_capabilities()->can_retransform_classes = 1;
347 }
348 }
349 }
350
351
352 void
353 JvmtiEnvBase::record_class_file_load_hook_enabled() {
354 if (!_class_file_load_hook_ever_enabled) {
355 if (Threads::number_of_threads() == 0) {
356 record_first_time_class_file_load_hook_enabled();
357 } else {
358 MutexLocker mu(JvmtiThreadState_lock);
359 record_first_time_class_file_load_hook_enabled();
360 }
361 }
362 }
363
364
365 jvmtiError
366 JvmtiEnvBase::set_native_method_prefixes(jint prefix_count, char** prefixes) {
367 assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(),
368 "sanity check");
369
370 int old_prefix_count = get_native_method_prefix_count();
371 char **old_prefixes = get_native_method_prefixes();
372
373 // allocate and install the new prefixex
374 if (prefix_count == 0 || !is_valid()) {
375 _native_method_prefix_count = 0;
376 _native_method_prefixes = NULL;
377 } else {
378 // there are prefixes, allocate an array to hold them, and fill it
379 char** new_prefixes = (char**)os::malloc((prefix_count) * sizeof(char*), mtInternal);
380 if (new_prefixes == NULL) {
381 return JVMTI_ERROR_OUT_OF_MEMORY;
382 }
383 for (int i = 0; i < prefix_count; i++) {
384 char* prefix = prefixes[i];
385 if (prefix == NULL) {
386 for (int j = 0; j < (i-1); j++) {
387 os::free(new_prefixes[j]);
388 }
389 os::free(new_prefixes);
390 return JVMTI_ERROR_NULL_POINTER;
391 }
392 prefix = os::strdup(prefixes[i]);
393 if (prefix == NULL) {
394 for (int j = 0; j < (i-1); j++) {
395 os::free(new_prefixes[j]);
396 }
397 os::free(new_prefixes);
398 return JVMTI_ERROR_OUT_OF_MEMORY;
399 }
400 new_prefixes[i] = prefix;
401 }
402 _native_method_prefix_count = prefix_count;
403 _native_method_prefixes = new_prefixes;
404 }
405
406 // now that we know the new prefixes have been successfully installed we can
407 // safely remove the old ones
408 if (old_prefix_count != 0) {
409 for (int i = 0; i < old_prefix_count; i++) {
410 os::free(old_prefixes[i]);
411 }
412 os::free(old_prefixes);
413 }
414
415 return JVMTI_ERROR_NONE;
416 }
417
418
419 // Collect all the prefixes which have been set in any JVM TI environments
420 // by the SetNativeMethodPrefix(es) functions. Be sure to maintain the
421 // order of environments and the order of prefixes within each environment.
422 // Return in a resource allocated array.
423 char**
424 JvmtiEnvBase::get_all_native_method_prefixes(int* count_ptr) {
425 assert(Threads::number_of_threads() == 0 ||
426 SafepointSynchronize::is_at_safepoint() ||
427 JvmtiThreadState_lock->is_locked(),
428 "sanity check");
429
430 int total_count = 0;
431 GrowableArray<char*>* prefix_array =new GrowableArray<char*>(5);
432
433 JvmtiEnvIterator it;
434 for (JvmtiEnvBase* env = it.first(); env != NULL; env = it.next(env)) {
435 int prefix_count = env->get_native_method_prefix_count();
436 char** prefixes = env->get_native_method_prefixes();
437 for (int j = 0; j < prefix_count; j++) {
438 // retrieve a prefix and so that it is safe against asynchronous changes
439 // copy it into the resource area
440 char* prefix = prefixes[j];
441 char* prefix_copy = NEW_RESOURCE_ARRAY(char, strlen(prefix)+1);
442 strcpy(prefix_copy, prefix);
443 prefix_array->at_put_grow(total_count++, prefix_copy);
444 }
445 }
446
447 char** all_prefixes = NEW_RESOURCE_ARRAY(char*, total_count);
448 char** p = all_prefixes;
449 for (int i = 0; i < total_count; ++i) {
450 *p++ = prefix_array->at(i);
451 }
452 *count_ptr = total_count;
453 return all_prefixes;
454 }
455
456 void
457 JvmtiEnvBase::set_event_callbacks(const jvmtiEventCallbacks* callbacks,
458 jint size_of_callbacks) {
459 assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(), "sanity check");
460
461 size_t byte_cnt = sizeof(jvmtiEventCallbacks);
462
463 // clear in either case to be sure we got any gap between sizes
464 memset(&_event_callbacks, 0, byte_cnt);
465
466 // Now that JvmtiThreadState_lock is held, prevent a possible race condition where events
467 // are re-enabled by a call to set event callbacks where the DisposeEnvironment
468 // occurs after the boiler-plate environment check and before the lock is acquired.
469 if (callbacks != NULL && is_valid()) {
470 if (size_of_callbacks < (jint)byte_cnt) {
471 byte_cnt = size_of_callbacks;
472 }
473 memcpy(&_event_callbacks, callbacks, byte_cnt);
474 }
475 }
476
477 // Called from JVMTI entry points which perform stack walking. If the
478 // associated JavaThread is the current thread, then wait_for_suspend
479 // is not used. Otherwise, it determines if we should wait for the
480 // "other" thread to complete external suspension. (NOTE: in future
481 // releases the suspension mechanism should be reimplemented so this
482 // is not necessary.)
483 //
484 bool
485 JvmtiEnvBase::is_thread_fully_suspended(JavaThread* thr, bool wait_for_suspend, uint32_t *bits) {
486 // "other" threads require special handling
487 if (thr != JavaThread::current()) {
488 if (wait_for_suspend) {
489 // We are allowed to wait for the external suspend to complete
490 // so give the other thread a chance to get suspended.
491 if (!thr->wait_for_ext_suspend_completion(SuspendRetryCount,
492 SuspendRetryDelay, bits)) {
493 // didn't make it so let the caller know
494 return false;
495 }
496 }
497 // We aren't allowed to wait for the external suspend to complete
498 // so if the other thread isn't externally suspended we need to
499 // let the caller know.
500 else if (!thr->is_ext_suspend_completed_with_lock(bits)) {
501 return false;
502 }
503 }
504
505 return true;
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;
515 jvmtiError result = allocate(size, &mem);
516 assert(result == JVMTI_ERROR_NONE, "Allocate failed");
517 return mem;
518 }
519
520
521 //
522 // Threads
523 //
524
525 jobject *
526 JvmtiEnvBase::new_jobjectArray(int length, Handle *handles) {
527 if (length == 0) {
528 return NULL;
529 }
530
531 jobject *objArray = (jobject *) jvmtiMalloc(sizeof(jobject) * length);
532 NULL_CHECK(objArray, NULL);
533
534 for (int i=0; i<length; i++) {
535 objArray[i] = jni_reference(handles[i]);
536 }
537 return objArray;
538 }
539
540 jthread *
541 JvmtiEnvBase::new_jthreadArray(int length, Handle *handles) {
542 return (jthread *) new_jobjectArray(length,handles);
543 }
544
545 jthreadGroup *
546 JvmtiEnvBase::new_jthreadGroupArray(int length, Handle *handles) {
547 return (jthreadGroup *) new_jobjectArray(length,handles);
548 }
549
550
551 JavaThread *
552 JvmtiEnvBase::get_JavaThread(jthread jni_thread) {
553 oop t = JNIHandles::resolve_external_guard(jni_thread);
554 if (t == NULL || !t->is_a(SystemDictionary::Thread_klass())) {
555 return NULL;
556 }
557 // The following returns NULL if the thread has not yet run or is in
558 // process of exiting
559 return java_lang_Thread::thread(t);
560 }
561
562
563 // return the vframe on the specified thread and depth, NULL if no such frame
564 vframe*
565 JvmtiEnvBase::vframeFor(JavaThread* java_thread, jint depth) {
566 if (!java_thread->has_last_Java_frame()) {
567 return NULL;
568 }
569 RegisterMap reg_map(java_thread);
570 vframe *vf = java_thread->last_java_vframe(®_map);
571 int d = 0;
572 while ((vf != NULL) && (d < depth)) {
573 vf = vf->java_sender();
574 d++;
575 }
576 return vf;
577 }
578
579
580 //
581 // utilities: JNI objects
582 //
583
584
585 jclass
586 JvmtiEnvBase::get_jni_class_non_null(Klass* k) {
587 assert(k != NULL, "k != NULL");
588 return (jclass)jni_reference(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 ResourceMark rm;
630 HandleMark hm;
631 RegisterMap reg_map(java_thread);
632
633 for(javaVFrame *jvf=java_thread->last_java_vframe(®_map); jvf != NULL;
634 jvf = jvf->java_sender()) {
635 GrowableArray<MonitorInfo*>* mons = jvf->monitors();
636 if (!mons->is_empty()) {
637 for (int i = 0; i < mons->length(); i++) {
638 MonitorInfo *mi = mons->at(i);
639 if (mi->owner_is_scalar_replaced()) continue;
640
641 // see if owner of the monitor is our object
642 if (mi->owner() != NULL && mi->owner() == hobj()) {
643 ret++;
644 }
645 }
646 }
647 }
648 return ret;
649 }
650
651
652
653 jvmtiError
654 JvmtiEnvBase::get_current_contended_monitor(JavaThread *calling_thread, JavaThread *java_thread, jobject *monitor_ptr) {
655 #ifdef ASSERT
656 uint32_t debug_bits = 0;
657 #endif
658 assert((SafepointSynchronize::is_at_safepoint() ||
659 is_thread_fully_suspended(java_thread, false, &debug_bits)),
660 "at safepoint or target thread is suspended");
661 oop obj = NULL;
662 ObjectMonitor *mon = java_thread->current_waiting_monitor();
663 if (mon == NULL) {
664 // thread is not doing an Object.wait() call
665 mon = java_thread->current_pending_monitor();
666 if (mon != NULL) {
667 // The thread is trying to enter() or raw_enter() an ObjectMonitor.
668 obj = (oop)mon->object();
669 // If obj == NULL, then ObjectMonitor is raw which doesn't count
670 // as contended for this API
671 }
672 // implied else: no contended ObjectMonitor
673 } else {
674 // thread is doing an Object.wait() call
675 obj = (oop)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;
683 Handle hobj(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 jvmtiError err = JVMTI_ERROR_NONE;
694 #ifdef ASSERT
695 uint32_t debug_bits = 0;
696 #endif
697 assert((SafepointSynchronize::is_at_safepoint() ||
698 is_thread_fully_suspended(java_thread, false, &debug_bits)),
699 "at safepoint or target thread is suspended");
700
701 if (java_thread->has_last_Java_frame()) {
702 ResourceMark rm;
703 HandleMark hm;
704 RegisterMap reg_map(java_thread);
705
706 int depth = 0;
707 for (javaVFrame *jvf = java_thread->last_java_vframe(®_map); jvf != NULL;
708 jvf = jvf->java_sender()) {
709 if (depth++ < MaxJavaStackTraceDepth) { // check for stack too deep
710 // add locked objects for this frame into list
711 err = get_locked_objects_in_frame(calling_thread, java_thread, jvf, owned_monitors_list, depth-1);
712 if (err != JVMTI_ERROR_NONE) {
713 return err;
714 }
715 }
716 }
717 }
718
719 // Get off stack monitors. (e.g. acquired via jni MonitorEnter).
720 JvmtiMonitorClosure jmc(java_thread, calling_thread, owned_monitors_list, this);
721 ObjectSynchronizer::monitors_iterate(&jmc);
722 err = jmc.error();
723
724 return err;
725 }
726
727 // Save JNI local handles for any objects that this frame owns.
728 jvmtiError
729 JvmtiEnvBase::get_locked_objects_in_frame(JavaThread* calling_thread, JavaThread* java_thread,
730 javaVFrame *jvf, GrowableArray<jvmtiMonitorStackDepthInfo*>* owned_monitors_list, int stack_depth) {
731 jvmtiError err = JVMTI_ERROR_NONE;
732 ResourceMark rm;
733
734 GrowableArray<MonitorInfo*>* mons = jvf->monitors();
735 if (mons->is_empty()) {
736 return err; // this javaVFrame holds no monitors
737 }
738
739 HandleMark hm;
740 oop wait_obj = NULL;
741 {
742 // save object of current wait() call (if any) for later comparison
743 ObjectMonitor *mon = java_thread->current_waiting_monitor();
744 if (mon != NULL) {
745 wait_obj = (oop)mon->object();
746 }
747 }
748 oop pending_obj = NULL;
749 {
750 // save object of current enter() call (if any) for later comparison
751 ObjectMonitor *mon = java_thread->current_pending_monitor();
752 if (mon != NULL) {
753 pending_obj = (oop)mon->object();
754 }
755 }
756
757 for (int i = 0; i < mons->length(); i++) {
758 MonitorInfo *mi = mons->at(i);
759
760 if (mi->owner_is_scalar_replaced()) continue;
761
762 oop obj = mi->owner();
763 if (obj == NULL) {
764 // this monitor doesn't have an owning object so skip it
765 continue;
766 }
767
768 if (wait_obj == obj) {
769 // the thread is waiting on this monitor so it isn't really owned
770 continue;
771 }
772
773 if (pending_obj == obj) {
774 // the thread is pending on this monitor so it isn't really owned
775 continue;
776 }
777
778 if (owned_monitors_list->length() > 0) {
779 // Our list has at least one object on it so we have to check
780 // for recursive object locking
781 bool found = false;
782 for (int j = 0; j < owned_monitors_list->length(); j++) {
783 jobject jobj = ((jvmtiMonitorStackDepthInfo*)owned_monitors_list->at(j))->monitor;
784 oop check = JNIHandles::resolve(jobj);
785 if (check == obj) {
786 found = true; // we found the object
787 break;
788 }
789 }
790
791 if (found) {
792 // already have this object so don't include it
793 continue;
794 }
795 }
796
797 // add the owning object to our list
798 jvmtiMonitorStackDepthInfo *jmsdi;
799 err = allocate(sizeof(jvmtiMonitorStackDepthInfo), (unsigned char **)&jmsdi);
800 if (err != JVMTI_ERROR_NONE) {
801 return err;
802 }
803 Handle hobj(obj);
804 jmsdi->monitor = jni_reference(calling_thread, hobj);
805 jmsdi->stack_depth = stack_depth;
806 owned_monitors_list->append(jmsdi);
807 }
808
809 return err;
810 }
811
812 jvmtiError
813 JvmtiEnvBase::get_stack_trace(JavaThread *java_thread,
814 jint start_depth, jint max_count,
815 jvmtiFrameInfo* frame_buffer, jint* count_ptr) {
816 #ifdef ASSERT
817 uint32_t debug_bits = 0;
818 #endif
819 assert((SafepointSynchronize::is_at_safepoint() ||
820 is_thread_fully_suspended(java_thread, false, &debug_bits)),
821 "at safepoint or target thread is suspended");
822 int count = 0;
823 if (java_thread->has_last_Java_frame()) {
824 RegisterMap reg_map(java_thread);
825 Thread* current_thread = Thread::current();
826 ResourceMark rm(current_thread);
827 javaVFrame *jvf = java_thread->last_java_vframe(®_map);
828 HandleMark hm(current_thread);
829 if (start_depth != 0) {
830 if (start_depth > 0) {
831 for (int j = 0; j < start_depth && jvf != NULL; j++) {
832 jvf = jvf->java_sender();
833 }
834 if (jvf == NULL) {
835 // start_depth is deeper than the stack depth
836 return JVMTI_ERROR_ILLEGAL_ARGUMENT;
837 }
838 } else { // start_depth < 0
839 // we are referencing the starting depth based on the oldest
840 // part of the stack.
841 // optimize to limit the number of times that java_sender() is called
842 javaVFrame *jvf_cursor = jvf;
843 javaVFrame *jvf_prev = NULL;
844 javaVFrame *jvf_prev_prev;
845 int j = 0;
846 while (jvf_cursor != NULL) {
847 jvf_prev_prev = jvf_prev;
848 jvf_prev = jvf_cursor;
849 for (j = 0; j > start_depth && jvf_cursor != NULL; j--) {
850 jvf_cursor = jvf_cursor->java_sender();
851 }
852 }
853 if (j == start_depth) {
854 // previous pointer is exactly where we want to start
855 jvf = jvf_prev;
856 } else {
857 // we need to back up further to get to the right place
858 if (jvf_prev_prev == NULL) {
859 // the -start_depth is greater than the stack depth
860 return JVMTI_ERROR_ILLEGAL_ARGUMENT;
861 }
862 // j now is the number of frames on the stack starting with
863 // jvf_prev, we start from jvf_prev_prev and move older on
864 // the stack that many, the result is -start_depth frames
865 // remaining.
866 jvf = jvf_prev_prev;
867 for (; j < 0; j++) {
868 jvf = jvf->java_sender();
869 }
870 }
871 }
872 }
873 for (; count < max_count && jvf != NULL; count++) {
874 frame_buffer[count].method = jvf->method()->jmethod_id();
875 frame_buffer[count].location = (jvf->method()->is_native() ? -1 : jvf->bci());
876 jvf = jvf->java_sender();
877 }
878 } else {
879 if (start_depth != 0) {
880 // no frames and there is a starting depth
881 return JVMTI_ERROR_ILLEGAL_ARGUMENT;
882 }
883 }
884 *count_ptr = count;
885 return JVMTI_ERROR_NONE;
886 }
887
888 jvmtiError
889 JvmtiEnvBase::get_frame_count(JvmtiThreadState *state, jint *count_ptr) {
890 assert((state != NULL),
891 "JavaThread should create JvmtiThreadState before calling this method");
892 *count_ptr = state->count_frames();
893 return JVMTI_ERROR_NONE;
894 }
895
896 jvmtiError
897 JvmtiEnvBase::get_frame_location(JavaThread *java_thread, jint depth,
898 jmethodID* method_ptr, jlocation* location_ptr) {
899 #ifdef ASSERT
900 uint32_t debug_bits = 0;
901 #endif
902 assert((SafepointSynchronize::is_at_safepoint() ||
903 is_thread_fully_suspended(java_thread, false, &debug_bits)),
904 "at safepoint or target thread is suspended");
905 Thread* current_thread = Thread::current();
906 ResourceMark rm(current_thread);
907
908 vframe *vf = vframeFor(java_thread, depth);
909 if (vf == NULL) {
910 return JVMTI_ERROR_NO_MORE_FRAMES;
911 }
912
913 // vframeFor should return a java frame. If it doesn't
914 // it means we've got an internal error and we return the
915 // error in product mode. In debug mode we will instead
916 // attempt to cast the vframe to a javaVFrame and will
917 // cause an assertion/crash to allow further diagnosis.
918 #ifdef PRODUCT
919 if (!vf->is_java_frame()) {
920 return JVMTI_ERROR_INTERNAL;
921 }
922 #endif
923
924 HandleMark hm(current_thread);
925 javaVFrame *jvf = javaVFrame::cast(vf);
926 Method* method = jvf->method();
927 if (method->is_native()) {
928 *location_ptr = -1;
929 } else {
930 *location_ptr = jvf->bci();
931 }
932 *method_ptr = method->jmethod_id();
933
934 return JVMTI_ERROR_NONE;
935 }
936
937
938 jvmtiError
939 JvmtiEnvBase::get_object_monitor_usage(JavaThread* calling_thread, jobject object, jvmtiMonitorUsage* info_ptr) {
940 HandleMark hm;
941 Handle hobj;
942
943 bool at_safepoint = SafepointSynchronize::is_at_safepoint();
944
945 // Check arguments
946 {
947 oop mirror = JNIHandles::resolve_external_guard(object);
948 NULL_CHECK(mirror, JVMTI_ERROR_INVALID_OBJECT);
949 NULL_CHECK(info_ptr, JVMTI_ERROR_NULL_POINTER);
950
951 hobj = Handle(mirror);
952 }
953
954 JavaThread *owning_thread = NULL;
955 ObjectMonitor *mon = NULL;
956 jvmtiMonitorUsage ret = {
957 NULL, 0, 0, NULL, 0, NULL
958 };
959
960 uint32_t debug_bits = 0;
961 // first derive the object's owner and entry_count (if any)
962 {
963 // Revoke any biases before querying the mark word
964 if (SafepointSynchronize::is_at_safepoint()) {
965 BiasedLocking::revoke_at_safepoint(hobj);
966 } else {
967 BiasedLocking::revoke_and_rebias(hobj, false, calling_thread);
968 }
969
970 address owner = NULL;
971 {
972 markOop mark = hobj()->mark();
973
974 if (!mark->has_monitor()) {
975 // this object has a lightweight monitor
976
977 if (mark->has_locker()) {
978 owner = (address)mark->locker(); // save the address of the Lock word
979 }
980 // implied else: no owner
981 } else {
982 // this object has a heavyweight monitor
983 mon = mark->monitor();
984
985 // The owner field of a heavyweight monitor may be NULL for no
986 // owner, a JavaThread * or it may still be the address of the
987 // Lock word in a JavaThread's stack. A monitor can be inflated
988 // by a non-owning JavaThread, but only the owning JavaThread
989 // can change the owner field from the Lock word to the
990 // JavaThread * and it may not have done that yet.
991 owner = (address)mon->owner();
992 }
993 }
994
995 if (owner != NULL) {
996 // This monitor is owned so we have to find the owning JavaThread.
997 // Since owning_thread_from_monitor_owner() grabs a lock, GC can
998 // move our object at this point. However, our owner value is safe
999 // since it is either the Lock word on a stack or a JavaThread *.
1000 owning_thread = Threads::owning_thread_from_monitor_owner(owner, !at_safepoint);
1001 // Cannot assume (owning_thread != NULL) here because this function
1002 // may not have been called at a safepoint and the owning_thread
1003 // might not be suspended.
1004 if (owning_thread != NULL) {
1005 // The monitor's owner either has to be the current thread, at safepoint
1006 // or it has to be suspended. Any of these conditions will prevent both
1007 // contending and waiting threads from modifying the state of
1008 // the monitor.
1009 if (!at_safepoint && !JvmtiEnv::is_thread_fully_suspended(owning_thread, true, &debug_bits)) {
1010 // Don't worry! This return of JVMTI_ERROR_THREAD_NOT_SUSPENDED
1011 // will not make it back to the JVM/TI agent. The error code will
1012 // get intercepted in JvmtiEnv::GetObjectMonitorUsage() which
1013 // will retry the call via a VM_GetObjectMonitorUsage VM op.
1014 return JVMTI_ERROR_THREAD_NOT_SUSPENDED;
1015 }
1016 HandleMark hm;
1017 Handle th(owning_thread->threadObj());
1018 ret.owner = (jthread)jni_reference(calling_thread, th);
1019 }
1020 // implied else: no owner
1021 }
1022
1023 if (owning_thread != NULL) { // monitor is owned
1024 // The recursions field of a monitor does not reflect recursions
1025 // as lightweight locks before inflating the monitor are not included.
1026 // We have to count the number of recursive monitor entries the hard way.
1027 // We pass a handle to survive any GCs along the way.
1028 ResourceMark rm;
1029 ret.entry_count = count_locked_objects(owning_thread, hobj);
1030 }
1031 // implied else: entry_count == 0
1032 }
1033
1034 jint nWant, nWait;
1035 if (mon != NULL) {
1036 // this object has a heavyweight monitor
1037 nWant = mon->contentions(); // # of threads contending for monitor
1038 nWait = mon->waiters(); // # of threads in Object.wait()
1039 ret.waiter_count = nWant + nWait;
1040 ret.notify_waiter_count = nWait;
1041 } else {
1042 // this object has a lightweight monitor
1043 ret.waiter_count = 0;
1044 ret.notify_waiter_count = 0;
1045 }
1046
1047 // Allocate memory for heavyweight and lightweight monitor.
1048 jvmtiError err;
1049 err = allocate(ret.waiter_count * sizeof(jthread *), (unsigned char**)&ret.waiters);
1050 if (err != JVMTI_ERROR_NONE) {
1051 return err;
1052 }
1053 err = allocate(ret.notify_waiter_count * sizeof(jthread *),
1054 (unsigned char**)&ret.notify_waiters);
1055 if (err != JVMTI_ERROR_NONE) {
1056 deallocate((unsigned char*)ret.waiters);
1057 return err;
1058 }
1059
1060 // now derive the rest of the fields
1061 if (mon != NULL) {
1062 // this object has a heavyweight monitor
1063
1064 // Number of waiters may actually be less than the waiter count.
1065 // So NULL out memory so that unused memory will be NULL.
1066 memset(ret.waiters, 0, ret.waiter_count * sizeof(jthread *));
1067 memset(ret.notify_waiters, 0, ret.notify_waiter_count * sizeof(jthread *));
1068
1069 if (ret.waiter_count > 0) {
1070 // we have contending and/or waiting threads
1071 HandleMark hm;
1072 if (nWant > 0) {
1073 // we have contending threads
1074 ResourceMark rm;
1075 // get_pending_threads returns only java thread so we do not need to
1076 // check for non java threads.
1077 GrowableArray<JavaThread*>* wantList = Threads::get_pending_threads(
1078 nWant, (address)mon, !at_safepoint);
1079 if (wantList->length() < nWant) {
1080 // robustness: the pending list has gotten smaller
1081 nWant = wantList->length();
1082 }
1083 for (int i = 0; i < nWant; i++) {
1084 JavaThread *pending_thread = wantList->at(i);
1085 // If the monitor has no owner, then a non-suspended contending
1086 // thread could potentially change the state of the monitor by
1087 // entering it. The JVM/TI spec doesn't allow this.
1088 if (owning_thread == NULL && !at_safepoint &
1089 !JvmtiEnv::is_thread_fully_suspended(pending_thread, true, &debug_bits)) {
1090 if (ret.owner != NULL) {
1091 destroy_jni_reference(calling_thread, ret.owner);
1092 }
1093 for (int j = 0; j < i; j++) {
1094 destroy_jni_reference(calling_thread, ret.waiters[j]);
1095 }
1096 deallocate((unsigned char*)ret.waiters);
1097 deallocate((unsigned char*)ret.notify_waiters);
1098 return JVMTI_ERROR_THREAD_NOT_SUSPENDED;
1099 }
1100 Handle th(pending_thread->threadObj());
1101 ret.waiters[i] = (jthread)jni_reference(calling_thread, th);
1102 }
1103 }
1104 if (nWait > 0) {
1105 // we have threads in Object.wait()
1106 int offset = nWant; // add after any contending threads
1107 ObjectWaiter *waiter = mon->first_waiter();
1108 for (int i = 0, j = 0; i < nWait; i++) {
1109 if (waiter == NULL) {
1110 // robustness: the waiting list has gotten smaller
1111 nWait = j;
1112 break;
1113 }
1114 Thread *t = mon->thread_of_waiter(waiter);
1115 if (t != NULL && t->is_Java_thread()) {
1116 JavaThread *wjava_thread = (JavaThread *)t;
1117 // If the thread was found on the ObjectWaiter list, then
1118 // it has not been notified. This thread can't change the
1119 // state of the monitor so it doesn't need to be suspended.
1120 Handle th(wjava_thread->threadObj());
1121 ret.waiters[offset + j] = (jthread)jni_reference(calling_thread, th);
1122 ret.notify_waiters[j++] = (jthread)jni_reference(calling_thread, th);
1123 }
1124 waiter = mon->next_waiter(waiter);
1125 }
1126 }
1127 }
1128
1129 // Adjust count. nWant and nWait count values may be less than original.
1130 ret.waiter_count = nWant + nWait;
1131 ret.notify_waiter_count = nWait;
1132 } else {
1133 // this object has a lightweight monitor and we have nothing more
1134 // to do here because the defaults are just fine.
1135 }
1136
1137 // we don't update return parameter unless everything worked
1138 *info_ptr = ret;
1139
1140 return JVMTI_ERROR_NONE;
1141 }
1142
1143 ResourceTracker::ResourceTracker(JvmtiEnv* env) {
1144 _env = env;
1145 _allocations = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<unsigned char*>(20, true);
1146 _failed = false;
1147 }
1148 ResourceTracker::~ResourceTracker() {
1149 if (_failed) {
1150 for (int i=0; i<_allocations->length(); i++) {
1151 _env->deallocate(_allocations->at(i));
1152 }
1153 }
1154 delete _allocations;
1155 }
1156
1157 jvmtiError ResourceTracker::allocate(jlong size, unsigned char** mem_ptr) {
1158 unsigned char *ptr;
1159 jvmtiError err = _env->allocate(size, &ptr);
1160 if (err == JVMTI_ERROR_NONE) {
1161 _allocations->append(ptr);
1162 *mem_ptr = ptr;
1163 } else {
1164 *mem_ptr = NULL;
1165 _failed = true;
1166 }
1167 return err;
1168 }
1169
1170 unsigned char* ResourceTracker::allocate(jlong size) {
1171 unsigned char* ptr;
1172 allocate(size, &ptr);
1173 return ptr;
1174 }
1175
1176 char* ResourceTracker::strdup(const char* str) {
1177 char *dup_str = (char*)allocate(strlen(str)+1);
1178 if (dup_str != NULL) {
1179 strcpy(dup_str, str);
1180 }
1181 return dup_str;
1182 }
1183
1184 struct StackInfoNode {
1185 struct StackInfoNode *next;
1186 jvmtiStackInfo info;
1187 };
1188
1189 // Create a jvmtiStackInfo inside a linked list node and create a
1190 // buffer for the frame information, both allocated as resource objects.
1191 // Fill in both the jvmtiStackInfo and the jvmtiFrameInfo.
1192 // Note that either or both of thr and thread_oop
1193 // may be null if the thread is new or has exited.
1194 void
1195 VM_GetMultipleStackTraces::fill_frames(jthread jt, JavaThread *thr, oop thread_oop) {
1196 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
1197
1198 jint state = 0;
1199 struct StackInfoNode *node = NEW_RESOURCE_OBJ(struct StackInfoNode);
1200 jvmtiStackInfo *infop = &(node->info);
1201 node->next = head();
1202 set_head(node);
1203 infop->frame_count = 0;
1204 infop->thread = jt;
1205
1206 if (thread_oop != NULL) {
1207 // get most state bits
1208 state = (jint)java_lang_Thread::get_thread_status(thread_oop);
1209 }
1210
1211 if (thr != NULL) { // add more state bits if there is a JavaThead to query
1212 // same as is_being_ext_suspended() but without locking
1213 if (thr->is_ext_suspended() || thr->is_external_suspend()) {
1214 state |= JVMTI_THREAD_STATE_SUSPENDED;
1215 }
1216 JavaThreadState jts = thr->thread_state();
1217 if (jts == _thread_in_native) {
1218 state |= JVMTI_THREAD_STATE_IN_NATIVE;
1219 }
1220 OSThread* osThread = thr->osthread();
1221 if (osThread != NULL && osThread->interrupted()) {
1222 state |= JVMTI_THREAD_STATE_INTERRUPTED;
1223 }
1224 }
1225 infop->state = state;
1226
1227 if (thr != NULL || (state & JVMTI_THREAD_STATE_ALIVE) != 0) {
1228 infop->frame_buffer = NEW_RESOURCE_ARRAY(jvmtiFrameInfo, max_frame_count());
1229 env()->get_stack_trace(thr, 0, max_frame_count(),
1230 infop->frame_buffer, &(infop->frame_count));
1231 } else {
1232 infop->frame_buffer = NULL;
1233 infop->frame_count = 0;
1234 }
1235 _frame_count_total += infop->frame_count;
1236 }
1237
1238 // Based on the stack information in the linked list, allocate memory
1239 // block to return and fill it from the info in the linked list.
1240 void
1241 VM_GetMultipleStackTraces::allocate_and_fill_stacks(jint thread_count) {
1242 // do I need to worry about alignment issues?
1243 jlong alloc_size = thread_count * sizeof(jvmtiStackInfo)
1244 + _frame_count_total * sizeof(jvmtiFrameInfo);
1245 env()->allocate(alloc_size, (unsigned char **)&_stack_info);
1246
1247 // pointers to move through the newly allocated space as it is filled in
1248 jvmtiStackInfo *si = _stack_info + thread_count; // bottom of stack info
1249 jvmtiFrameInfo *fi = (jvmtiFrameInfo *)si; // is the top of frame info
1250
1251 // copy information in resource area into allocated buffer
1252 // insert stack info backwards since linked list is backwards
1253 // insert frame info forwards
1254 // walk the StackInfoNodes
1255 for (struct StackInfoNode *sin = head(); sin != NULL; sin = sin->next) {
1256 jint frame_count = sin->info.frame_count;
1257 size_t frames_size = frame_count * sizeof(jvmtiFrameInfo);
1258 --si;
1259 memcpy(si, &(sin->info), sizeof(jvmtiStackInfo));
1260 if (frames_size == 0) {
1261 si->frame_buffer = NULL;
1262 } else {
1263 memcpy(fi, sin->info.frame_buffer, frames_size);
1264 si->frame_buffer = fi; // point to the new allocated copy of the frames
1265 fi += frame_count;
1266 }
1267 }
1268 assert(si == _stack_info, "the last copied stack info must be the first record");
1269 assert((unsigned char *)fi == ((unsigned char *)_stack_info) + alloc_size,
1270 "the last copied frame info must be the last record");
1271 }
1272
1273
1274 void
1275 VM_GetThreadListStackTraces::doit() {
1276 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
1277
1278 ResourceMark rm;
1279 for (int i = 0; i < _thread_count; ++i) {
1280 jthread jt = _thread_list[i];
1281 oop thread_oop = JNIHandles::resolve_external_guard(jt);
1282 if (thread_oop == NULL || !thread_oop->is_a(SystemDictionary::Thread_klass())) {
1283 set_result(JVMTI_ERROR_INVALID_THREAD);
1284 return;
1285 }
1286 fill_frames(jt, java_lang_Thread::thread(thread_oop), thread_oop);
1287 }
1288 allocate_and_fill_stacks(_thread_count);
1289 }
1290
1291 void
1292 VM_GetAllStackTraces::doit() {
1293 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
1294
1295 ResourceMark rm;
1296 _final_thread_count = 0;
1297 for (JavaThread *jt = Threads::first(); jt != NULL; jt = jt->next()) {
1298 oop thread_oop = jt->threadObj();
1299 if (thread_oop != NULL &&
1300 !jt->is_exiting() &&
1301 java_lang_Thread::is_alive(thread_oop) &&
1302 !jt->is_hidden_from_external_view()) {
1303 ++_final_thread_count;
1304 // Handle block of the calling thread is used to create local refs.
1305 fill_frames((jthread)JNIHandles::make_local(_calling_thread, thread_oop),
1306 jt, thread_oop);
1307 }
1308 }
1309 allocate_and_fill_stacks(_final_thread_count);
1310 }
1311
1312 // Verifies that the top frame is a java frame in an expected state.
1313 // Deoptimizes frame if needed.
1314 // Checks that the frame method signature matches the return type (tos).
1315 // HandleMark must be defined in the caller only.
1316 // It is to keep a ret_ob_h handle alive after return to the caller.
1317 jvmtiError
1318 JvmtiEnvBase::check_top_frame(JavaThread* current_thread, JavaThread* java_thread,
1319 jvalue value, TosState tos, Handle* ret_ob_h) {
1320 ResourceMark rm(current_thread);
1321
1322 vframe *vf = vframeFor(java_thread, 0);
1323 NULL_CHECK(vf, JVMTI_ERROR_NO_MORE_FRAMES);
1324
1325 javaVFrame *jvf = (javaVFrame*) vf;
1326 if (!vf->is_java_frame() || jvf->method()->is_native()) {
1327 return JVMTI_ERROR_OPAQUE_FRAME;
1328 }
1329
1330 // If the frame is a compiled one, need to deoptimize it.
1331 if (vf->is_compiled_frame()) {
1332 if (!vf->fr().can_be_deoptimized()) {
1333 return JVMTI_ERROR_OPAQUE_FRAME;
1334 }
1335 Deoptimization::deoptimize_frame(java_thread, jvf->fr().id());
1336 }
1337
1338 // Get information about method return type
1339 Symbol* signature = jvf->method()->signature();
1340
1341 ResultTypeFinder rtf(signature);
1342 TosState fr_tos = as_TosState(rtf.type());
1343 if (fr_tos != tos) {
1344 if (tos != itos || (fr_tos != btos && fr_tos != ctos && fr_tos != stos)) {
1345 return JVMTI_ERROR_TYPE_MISMATCH;
1346 }
1347 }
1348
1349 // Check that the jobject class matches the return type signature.
1350 jobject jobj = value.l;
1351 if (tos == atos && jobj != NULL) { // NULL reference is allowed
1352 Handle ob_h = Handle(current_thread, JNIHandles::resolve_external_guard(jobj));
1353 NULL_CHECK(ob_h, JVMTI_ERROR_INVALID_OBJECT);
1354 KlassHandle ob_kh = KlassHandle(current_thread, ob_h()->klass());
1355 NULL_CHECK(ob_kh, JVMTI_ERROR_INVALID_OBJECT);
1356
1357 // Method return type signature.
1358 char* ty_sign = 1 + strchr(signature->as_C_string(), ')');
1359
1360 if (!VM_GetOrSetLocal::is_assignable(ty_sign, ob_kh(), current_thread)) {
1361 return JVMTI_ERROR_TYPE_MISMATCH;
1362 }
1363 *ret_ob_h = ob_h;
1364 }
1365 return JVMTI_ERROR_NONE;
1366 } /* end check_top_frame */
1367
1368
1369 // ForceEarlyReturn<type> follows the PopFrame approach in many aspects.
1370 // Main difference is on the last stage in the interpreter.
1371 // The PopFrame stops method execution to continue execution
1372 // from the same method call instruction.
1373 // The ForceEarlyReturn forces return from method so the execution
1374 // continues at the bytecode following the method call.
1375
1376 // Threads_lock NOT held, java_thread not protected by lock
1377 // java_thread - pre-checked
1378
1379 jvmtiError
1380 JvmtiEnvBase::force_early_return(JavaThread* java_thread, jvalue value, TosState tos) {
1381 JavaThread* current_thread = JavaThread::current();
1382 HandleMark hm(current_thread);
1383 uint32_t debug_bits = 0;
1384
1385 // retrieve or create the state
1386 JvmtiThreadState* state = JvmtiThreadState::state_for(java_thread);
1387 if (state == NULL) {
1388 return JVMTI_ERROR_THREAD_NOT_ALIVE;
1389 }
1390
1391 // Check if java_thread is fully suspended
1392 if (!is_thread_fully_suspended(java_thread,
1393 true /* wait for suspend completion */,
1394 &debug_bits)) {
1395 return JVMTI_ERROR_THREAD_NOT_SUSPENDED;
1396 }
1397
1398 // Check to see if a ForceEarlyReturn was already in progress
1399 if (state->is_earlyret_pending()) {
1400 // Probably possible for JVMTI clients to trigger this, but the
1401 // JPDA backend shouldn't allow this to happen
1402 return JVMTI_ERROR_INTERNAL;
1403 }
1404 {
1405 // The same as for PopFrame. Workaround bug:
1406 // 4812902: popFrame hangs if the method is waiting at a synchronize
1407 // Catch this condition and return an error to avoid hanging.
1408 // Now JVMTI spec allows an implementation to bail out with an opaque
1409 // frame error.
1410 OSThread* osThread = java_thread->osthread();
1411 if (osThread->get_state() == MONITOR_WAIT) {
1412 return JVMTI_ERROR_OPAQUE_FRAME;
1413 }
1414 }
1415 Handle ret_ob_h = Handle();
1416 jvmtiError err = check_top_frame(current_thread, java_thread, value, tos, &ret_ob_h);
1417 if (err != JVMTI_ERROR_NONE) {
1418 return err;
1419 }
1420 assert(tos != atos || value.l == NULL || ret_ob_h() != NULL,
1421 "return object oop must not be NULL if jobject is not NULL");
1422
1423 // Update the thread state to reflect that the top frame must be
1424 // forced to return.
1425 // The current frame will be returned later when the suspended
1426 // thread is resumed and right before returning from VM to Java.
1427 // (see call_VM_base() in assembler_<cpu>.cpp).
1428
1429 state->set_earlyret_pending();
1430 state->set_earlyret_oop(ret_ob_h());
1431 state->set_earlyret_value(value, tos);
1432
1433 // Set pending step flag for this early return.
1434 // It is cleared when next step event is posted.
1435 state->set_pending_step_for_earlyret();
1436
1437 return JVMTI_ERROR_NONE;
1438 } /* end force_early_return */
1439
1440 void
1441 JvmtiMonitorClosure::do_monitor(ObjectMonitor* mon) {
1442 if ( _error != JVMTI_ERROR_NONE) {
1443 // Error occurred in previous iteration so no need to add
1444 // to the list.
1445 return;
1446 }
1447 if (mon->owner() == _java_thread ) {
1448 // Filter out on stack monitors collected during stack walk.
1449 oop obj = (oop)mon->object();
1450 bool found = false;
1451 for (int j = 0; j < _owned_monitors_list->length(); j++) {
1452 jobject jobj = ((jvmtiMonitorStackDepthInfo*)_owned_monitors_list->at(j))->monitor;
1453 oop check = JNIHandles::resolve(jobj);
1454 if (check == obj) {
1455 // On stack monitor already collected during the stack walk.
1456 found = true;
1457 break;
1458 }
1459 }
1460 if (found == false) {
1461 // This is off stack monitor (e.g. acquired via jni MonitorEnter).
1462 jvmtiError err;
1463 jvmtiMonitorStackDepthInfo *jmsdi;
1464 err = _env->allocate(sizeof(jvmtiMonitorStackDepthInfo), (unsigned char **)&jmsdi);
1465 if (err != JVMTI_ERROR_NONE) {
1466 _error = err;
1467 return;
1468 }
1469 Handle hobj(obj);
1470 jmsdi->monitor = _env->jni_reference(_calling_thread, hobj);
1471 // stack depth is unknown for this monitor.
1472 jmsdi->stack_depth = -1;
1473 _owned_monitors_list->append(jmsdi);
1474 }
1475 }
1476 }