1 /*
2 * Copyright (c) 2003, 2011, 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/vframe.hpp"
45 #include "runtime/vframe_hp.hpp"
46 #include "runtime/vmThread.hpp"
47 #include "runtime/vm_operations.hpp"
48
49 ///////////////////////////////////////////////////////////////
50 //
51 // JvmtiEnvBase
52 //
53
54 JvmtiEnvBase* JvmtiEnvBase::_head_environment = NULL;
55
56 bool JvmtiEnvBase::_globally_initialized = false;
57 volatile bool JvmtiEnvBase::_needs_clean_up = false;
58
59 jvmtiPhase JvmtiEnvBase::_phase = JVMTI_PHASE_PRIMORDIAL;
60
61 volatile int JvmtiEnvBase::_dying_thread_env_iteration_count = 0;
62
63 extern jvmtiInterface_1_ jvmti_Interface;
64 extern jvmtiInterface_1_ jvmtiTrace_Interface;
65
66
67 // perform initializations that must occur before any JVMTI environments
68 // are released but which should only be initialized once (no matter
69 // how many environments are created).
70 void
71 JvmtiEnvBase::globally_initialize() {
72 assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(), "sanity check");
73 assert(_globally_initialized == false, "bad call");
74
75 JvmtiManageCapabilities::initialize();
76
77 #ifndef JVMTI_KERNEL
78 // register extension functions and events
79 JvmtiExtensions::register_extensions();
80 #endif // !JVMTI_KERNEL
81
82 #ifdef JVMTI_TRACE
83 JvmtiTrace::initialize();
84 #endif
85
86 _globally_initialized = true;
87 }
88
89
90 void
91 JvmtiEnvBase::initialize() {
92 assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(), "sanity check");
93
94 // Add this environment to the end of the environment list (order is important)
95 {
96 // This block of code must not contain any safepoints, as list deallocation
97 // (which occurs at a safepoint) cannot occur simultaneously with this list
98 // addition. Note: No_Safepoint_Verifier cannot, currently, be used before
99 // threads exist.
100 JvmtiEnvIterator it;
101 JvmtiEnvBase *previous_env = NULL;
102 for (JvmtiEnvBase* env = it.first(); env != NULL; env = it.next(env)) {
103 previous_env = env;
104 }
105 if (previous_env == NULL) {
106 _head_environment = this;
107 } else {
108 previous_env->set_next_environment(this);
109 }
110 }
111
112 if (_globally_initialized == false) {
113 globally_initialize();
114 }
115 }
116
117
118 bool
119 JvmtiEnvBase::is_valid() {
120 jint value = 0;
121
122 // This object might not be a JvmtiEnvBase so we can't assume
123 // the _magic field is properly aligned. Get the value in a safe
124 // way and then check against JVMTI_MAGIC.
125
126 switch (sizeof(_magic)) {
127 case 2:
128 value = Bytes::get_native_u2((address)&_magic);
129 break;
130
131 case 4:
132 value = Bytes::get_native_u4((address)&_magic);
133 break;
134
135 case 8:
136 value = Bytes::get_native_u8((address)&_magic);
137 break;
138
139 default:
140 guarantee(false, "_magic field is an unexpected size");
141 }
142
143 return value == JVMTI_MAGIC;
144 }
145
146
147 bool
148 JvmtiEnvBase::use_version_1_0_semantics() {
149 int major, minor, micro;
150
151 JvmtiExport::decode_version_values(_version, &major, &minor, µ);
152 return major == 1 && minor == 0; // micro version doesn't matter here
153 }
154
155
156 bool
157 JvmtiEnvBase::use_version_1_1_semantics() {
158 int major, minor, micro;
159
160 JvmtiExport::decode_version_values(_version, &major, &minor, µ);
161 return major == 1 && minor == 1; // micro version doesn't matter here
162 }
163
164 bool
165 JvmtiEnvBase::use_version_1_2_semantics() {
166 int major, minor, micro;
167
168 JvmtiExport::decode_version_values(_version, &major, &minor, µ);
169 return major == 1 && minor == 2; // micro version doesn't matter here
170 }
171
172
173 JvmtiEnvBase::JvmtiEnvBase(jint version) : _env_event_enable() {
174 _version = version;
175 _env_local_storage = NULL;
176 _tag_map = NULL;
177 _native_method_prefix_count = 0;
178 _native_method_prefixes = NULL;
179 _next = NULL;
180 _class_file_load_hook_ever_enabled = false;
181
182 // Moot since ClassFileLoadHook not yet enabled.
183 // But "true" will give a more predictable ClassFileLoadHook behavior
184 // for environment creation during ClassFileLoadHook.
185 _is_retransformable = true;
186
187 // all callbacks initially NULL
188 memset(&_event_callbacks,0,sizeof(jvmtiEventCallbacks));
189
190 // all capabilities initially off
191 memset(&_current_capabilities, 0, sizeof(_current_capabilities));
192
193 // all prohibited capabilities initially off
194 memset(&_prohibited_capabilities, 0, sizeof(_prohibited_capabilities));
195
196 _magic = JVMTI_MAGIC;
197
198 JvmtiEventController::env_initialize((JvmtiEnv*)this);
199
200 #ifdef JVMTI_TRACE
201 _jvmti_external.functions = TraceJVMTI != NULL ? &jvmtiTrace_Interface : &jvmti_Interface;
202 #else
203 _jvmti_external.functions = &jvmti_Interface;
204 #endif
205 }
206
207
208 void
209 JvmtiEnvBase::dispose() {
210
211 #ifdef JVMTI_TRACE
212 JvmtiTrace::shutdown();
213 #endif
214
215 // Dispose of event info and let the event controller call us back
216 // in a locked state (env_dispose, below)
217 JvmtiEventController::env_dispose(this);
218 }
219
220 void
221 JvmtiEnvBase::env_dispose() {
222 assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(), "sanity check");
223
224 // We have been entered with all events disabled on this environment.
225 // A race to re-enable events (by setting callbacks) is prevented by
226 // checking for a valid environment when setting callbacks (while
227 // holding the JvmtiThreadState_lock).
228
229 // Mark as invalid.
230 _magic = DISPOSED_MAGIC;
231
232 // Relinquish all capabilities.
233 jvmtiCapabilities *caps = get_capabilities();
234 JvmtiManageCapabilities::relinquish_capabilities(caps, caps, caps);
235
236 // Same situation as with events (see above)
237 set_native_method_prefixes(0, NULL);
238
239 #ifndef JVMTI_KERNEL
240 JvmtiTagMap* tag_map_to_deallocate = _tag_map;
241 set_tag_map(NULL);
242 // A tag map can be big, deallocate it now
243 if (tag_map_to_deallocate != NULL) {
244 delete tag_map_to_deallocate;
245 }
246 #endif // !JVMTI_KERNEL
247
248 _needs_clean_up = true;
249 }
250
251
252 JvmtiEnvBase::~JvmtiEnvBase() {
253 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
254
255 // There is a small window of time during which the tag map of a
256 // disposed environment could have been reallocated.
257 // Make sure it is gone.
258 #ifndef JVMTI_KERNEL
259 JvmtiTagMap* tag_map_to_deallocate = _tag_map;
260 set_tag_map(NULL);
261 // A tag map can be big, deallocate it now
262 if (tag_map_to_deallocate != NULL) {
263 delete tag_map_to_deallocate;
264 }
265 #endif // !JVMTI_KERNEL
266
267 _magic = BAD_MAGIC;
268 }
269
270
271 void
272 JvmtiEnvBase::periodic_clean_up() {
273 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
274
275 // JvmtiEnvBase reference is saved in JvmtiEnvThreadState. So
276 // clean up JvmtiThreadState before deleting JvmtiEnv pointer.
277 JvmtiThreadState::periodic_clean_up();
278
279 // Unlink all invalid environments from the list of environments
280 // and deallocate them
281 JvmtiEnvIterator it;
282 JvmtiEnvBase* previous_env = NULL;
283 JvmtiEnvBase* env = it.first();
284 while (env != NULL) {
285 if (env->is_valid()) {
286 previous_env = env;
287 env = it.next(env);
288 } else {
289 // This one isn't valid, remove it from the list and deallocate it
290 JvmtiEnvBase* defunct_env = env;
291 env = it.next(env);
292 if (previous_env == NULL) {
293 _head_environment = env;
294 } else {
295 previous_env->set_next_environment(env);
296 }
297 delete defunct_env;
298 }
299 }
300
301 }
302
303
304 void
305 JvmtiEnvBase::check_for_periodic_clean_up() {
306 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
307
308 class ThreadInsideIterationClosure: public ThreadClosure {
309 private:
310 bool _inside;
311 public:
312 ThreadInsideIterationClosure() : _inside(false) {};
313
314 void do_thread(Thread* thread) {
315 _inside |= thread->is_inside_jvmti_env_iteration();
316 }
317
318 bool is_inside_jvmti_env_iteration() {
319 return _inside;
320 }
321 };
322
323 if (_needs_clean_up) {
324 // Check if we are currently iterating environment,
325 // deallocation should not occur if we are
326 ThreadInsideIterationClosure tiic;
327 Threads::threads_do(&tiic);
328 if (!tiic.is_inside_jvmti_env_iteration() &&
329 !is_inside_dying_thread_env_iteration()) {
330 _needs_clean_up = false;
331 JvmtiEnvBase::periodic_clean_up();
332 }
333 }
334 }
335
336
337 void
338 JvmtiEnvBase::record_first_time_class_file_load_hook_enabled() {
339 assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(),
340 "sanity check");
341
342 if (!_class_file_load_hook_ever_enabled) {
343 _class_file_load_hook_ever_enabled = true;
344
345 if (get_capabilities()->can_retransform_classes) {
346 _is_retransformable = true;
347 } else {
348 _is_retransformable = false;
349
350 // cannot add retransform capability after ClassFileLoadHook has been enabled
351 get_prohibited_capabilities()->can_retransform_classes = 1;
352 }
353 }
354 }
355
356
357 void
358 JvmtiEnvBase::record_class_file_load_hook_enabled() {
359 if (!_class_file_load_hook_ever_enabled) {
360 if (Threads::number_of_threads() == 0) {
361 record_first_time_class_file_load_hook_enabled();
362 } else {
363 MutexLocker mu(JvmtiThreadState_lock);
364 record_first_time_class_file_load_hook_enabled();
365 }
366 }
367 }
368
369
370 jvmtiError
371 JvmtiEnvBase::set_native_method_prefixes(jint prefix_count, char** prefixes) {
372 assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(),
373 "sanity check");
374
375 int old_prefix_count = get_native_method_prefix_count();
376 char **old_prefixes = get_native_method_prefixes();
377
378 // allocate and install the new prefixex
379 if (prefix_count == 0 || !is_valid()) {
380 _native_method_prefix_count = 0;
381 _native_method_prefixes = NULL;
382 } else {
383 // there are prefixes, allocate an array to hold them, and fill it
384 char** new_prefixes = (char**)os::malloc((prefix_count) * sizeof(char*));
385 if (new_prefixes == NULL) {
386 return JVMTI_ERROR_OUT_OF_MEMORY;
387 }
388 for (int i = 0; i < prefix_count; i++) {
389 char* prefix = prefixes[i];
390 if (prefix == NULL) {
391 for (int j = 0; j < (i-1); j++) {
392 os::free(new_prefixes[j]);
393 }
394 os::free(new_prefixes);
395 return JVMTI_ERROR_NULL_POINTER;
396 }
397 prefix = os::strdup(prefixes[i]);
398 if (prefix == NULL) {
399 for (int j = 0; j < (i-1); j++) {
400 os::free(new_prefixes[j]);
401 }
402 os::free(new_prefixes);
403 return JVMTI_ERROR_OUT_OF_MEMORY;
404 }
405 new_prefixes[i] = prefix;
406 }
407 _native_method_prefix_count = prefix_count;
408 _native_method_prefixes = new_prefixes;
409 }
410
411 // now that we know the new prefixes have been successfully installed we can
412 // safely remove the old ones
413 if (old_prefix_count != 0) {
414 for (int i = 0; i < old_prefix_count; i++) {
415 os::free(old_prefixes[i]);
416 }
417 os::free(old_prefixes);
418 }
419
420 return JVMTI_ERROR_NONE;
421 }
422
423
424 // Collect all the prefixes which have been set in any JVM TI environments
425 // by the SetNativeMethodPrefix(es) functions. Be sure to maintain the
426 // order of environments and the order of prefixes within each environment.
427 // Return in a resource allocated array.
428 char**
429 JvmtiEnvBase::get_all_native_method_prefixes(int* count_ptr) {
430 assert(Threads::number_of_threads() == 0 ||
431 SafepointSynchronize::is_at_safepoint() ||
432 JvmtiThreadState_lock->is_locked(),
433 "sanity check");
434
435 int total_count = 0;
436 GrowableArray<char*>* prefix_array =new GrowableArray<char*>(5);
437
438 JvmtiEnvIterator it;
439 for (JvmtiEnvBase* env = it.first(); env != NULL; env = it.next(env)) {
440 int prefix_count = env->get_native_method_prefix_count();
441 char** prefixes = env->get_native_method_prefixes();
442 for (int j = 0; j < prefix_count; j++) {
443 // retrieve a prefix and so that it is safe against asynchronous changes
444 // copy it into the resource area
445 char* prefix = prefixes[j];
446 char* prefix_copy = NEW_RESOURCE_ARRAY(char, strlen(prefix)+1);
447 strcpy(prefix_copy, prefix);
448 prefix_array->at_put_grow(total_count++, prefix_copy);
449 }
450 }
451
452 char** all_prefixes = NEW_RESOURCE_ARRAY(char*, total_count);
453 char** p = all_prefixes;
454 for (int i = 0; i < total_count; ++i) {
455 *p++ = prefix_array->at(i);
456 }
457 *count_ptr = total_count;
458 return all_prefixes;
459 }
460
461 void
462 JvmtiEnvBase::set_event_callbacks(const jvmtiEventCallbacks* callbacks,
463 jint size_of_callbacks) {
464 assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(), "sanity check");
465
466 size_t byte_cnt = sizeof(jvmtiEventCallbacks);
467
468 // clear in either case to be sure we got any gap between sizes
469 memset(&_event_callbacks, 0, byte_cnt);
470
471 // Now that JvmtiThreadState_lock is held, prevent a possible race condition where events
472 // are re-enabled by a call to set event callbacks where the DisposeEnvironment
473 // occurs after the boiler-plate environment check and before the lock is acquired.
474 if (callbacks != NULL && is_valid()) {
475 if (size_of_callbacks < (jint)byte_cnt) {
476 byte_cnt = size_of_callbacks;
477 }
478 memcpy(&_event_callbacks, callbacks, byte_cnt);
479 }
480 }
481
482 // Called from JVMTI entry points which perform stack walking. If the
483 // associated JavaThread is the current thread, then wait_for_suspend
484 // is not used. Otherwise, it determines if we should wait for the
485 // "other" thread to complete external suspension. (NOTE: in future
486 // releases the suspension mechanism should be reimplemented so this
487 // is not necessary.)
488 //
489 bool
490 JvmtiEnvBase::is_thread_fully_suspended(JavaThread* thr, bool wait_for_suspend, uint32_t *bits) {
491 // "other" threads require special handling
492 if (thr != JavaThread::current()) {
493 if (wait_for_suspend) {
494 // We are allowed to wait for the external suspend to complete
495 // so give the other thread a chance to get suspended.
496 if (!thr->wait_for_ext_suspend_completion(SuspendRetryCount,
497 SuspendRetryDelay, bits)) {
498 // didn't make it so let the caller know
499 return false;
500 }
501 }
502 // We aren't allowed to wait for the external suspend to complete
503 // so if the other thread isn't externally suspended we need to
504 // let the caller know.
505 else if (!thr->is_ext_suspend_completed_with_lock(bits)) {
506 return false;
507 }
508 }
509
510 return true;
511 }
512
513
514 // In the fullness of time, all users of the method should instead
515 // directly use allocate, besides being cleaner and faster, this will
516 // mean much better out of memory handling
517 unsigned char *
518 JvmtiEnvBase::jvmtiMalloc(jlong size) {
519 unsigned char* mem;
520 jvmtiError result = allocate(size, &mem);
521 assert(result == JVMTI_ERROR_NONE, "Allocate failed");
522 return mem;
523 }
524
525
526 //
527 // Threads
528 //
529
530 jobject *
531 JvmtiEnvBase::new_jobjectArray(int length, Handle *handles) {
532 if (length == 0) {
533 return NULL;
534 }
535
536 jobject *objArray = (jobject *) jvmtiMalloc(sizeof(jobject) * length);
537 NULL_CHECK(objArray, NULL);
538
539 for (int i=0; i<length; i++) {
540 objArray[i] = jni_reference(handles[i]);
541 }
542 return objArray;
543 }
544
545 jthread *
546 JvmtiEnvBase::new_jthreadArray(int length, Handle *handles) {
547 return (jthread *) new_jobjectArray(length,handles);
548 }
549
550 jthreadGroup *
551 JvmtiEnvBase::new_jthreadGroupArray(int length, Handle *handles) {
552 return (jthreadGroup *) new_jobjectArray(length,handles);
553 }
554
555
556 JavaThread *
557 JvmtiEnvBase::get_JavaThread(jthread jni_thread) {
558 oop t = JNIHandles::resolve_external_guard(jni_thread);
559 if (t == NULL || !t->is_a(SystemDictionary::Thread_klass())) {
560 return NULL;
561 }
562 // The following returns NULL if the thread has not yet run or is in
563 // process of exiting
564 return java_lang_Thread::thread(t);
565 }
566
567
568 // return the vframe on the specified thread and depth, NULL if no such frame
569 vframe*
570 JvmtiEnvBase::vframeFor(JavaThread* java_thread, jint depth) {
571 if (!java_thread->has_last_Java_frame()) {
572 return NULL;
573 }
574 RegisterMap reg_map(java_thread);
575 vframe *vf = java_thread->last_java_vframe(®_map);
576 int d = 0;
577 while ((vf != NULL) && (d < depth)) {
578 vf = vf->java_sender();
579 d++;
580 }
581 return vf;
582 }
583
584
585 //
586 // utilities: JNI objects
587 //
588
589
590 jclass
591 JvmtiEnvBase::get_jni_class_non_null(klassOop k) {
592 assert(k != NULL, "k != NULL");
593 return (jclass)jni_reference(Klass::cast(k)->java_mirror());
594 }
595
596 #ifndef JVMTI_KERNEL
597
598 //
599 // Field Information
600 //
601
602 bool
603 JvmtiEnvBase::get_field_descriptor(klassOop k, jfieldID field, fieldDescriptor* fd) {
604 if (!jfieldIDWorkaround::is_valid_jfieldID(k, field)) {
605 return false;
606 }
607 bool found = false;
608 if (jfieldIDWorkaround::is_static_jfieldID(field)) {
609 JNIid* id = jfieldIDWorkaround::from_static_jfieldID(field);
610 found = id->find_local_field(fd);
611 } else {
612 // Non-static field. The fieldID is really the offset of the field within the object.
613 int offset = jfieldIDWorkaround::from_instance_jfieldID(k, field);
614 found = instanceKlass::cast(k)->find_field_from_offset(offset, false, fd);
615 }
616 return found;
617 }
618
619 //
620 // Object Monitor Information
621 //
622
623 //
624 // Count the number of objects for a lightweight monitor. The hobj
625 // parameter is object that owns the monitor so this routine will
626 // count the number of times the same object was locked by frames
627 // in java_thread.
628 //
629 jint
630 JvmtiEnvBase::count_locked_objects(JavaThread *java_thread, Handle hobj) {
631 jint ret = 0;
632 if (!java_thread->has_last_Java_frame()) {
633 return ret; // no Java frames so no monitors
634 }
635
636 ResourceMark rm;
637 HandleMark hm;
638 RegisterMap reg_map(java_thread);
639
640 for(javaVFrame *jvf=java_thread->last_java_vframe(®_map); jvf != NULL;
641 jvf = jvf->java_sender()) {
642 GrowableArray<MonitorInfo*>* mons = jvf->monitors();
643 if (!mons->is_empty()) {
644 for (int i = 0; i < mons->length(); i++) {
645 MonitorInfo *mi = mons->at(i);
646 if (mi->owner_is_scalar_replaced()) continue;
647
648 // see if owner of the monitor is our object
649 if (mi->owner() != NULL && mi->owner() == hobj()) {
650 ret++;
651 }
652 }
653 }
654 }
655 return ret;
656 }
657
658
659
660 jvmtiError
661 JvmtiEnvBase::get_current_contended_monitor(JavaThread *calling_thread, JavaThread *java_thread, jobject *monitor_ptr) {
662 #ifdef ASSERT
663 uint32_t debug_bits = 0;
664 #endif
665 assert((SafepointSynchronize::is_at_safepoint() ||
666 is_thread_fully_suspended(java_thread, false, &debug_bits)),
667 "at safepoint or target thread is suspended");
668 oop obj = NULL;
669 ObjectMonitor *mon = java_thread->current_waiting_monitor();
670 if (mon == NULL) {
671 // thread is not doing an Object.wait() call
672 mon = java_thread->current_pending_monitor();
673 if (mon != NULL) {
674 // The thread is trying to enter() or raw_enter() an ObjectMonitor.
675 obj = (oop)mon->object();
676 // If obj == NULL, then ObjectMonitor is raw which doesn't count
677 // as contended for this API
678 }
679 // implied else: no contended ObjectMonitor
680 } else {
681 // thread is doing an Object.wait() call
682 obj = (oop)mon->object();
683 assert(obj != NULL, "Object.wait() should have an object");
684 }
685
686 if (obj == NULL) {
687 *monitor_ptr = NULL;
688 } else {
689 HandleMark hm;
690 Handle hobj(obj);
691 *monitor_ptr = jni_reference(calling_thread, hobj);
692 }
693 return JVMTI_ERROR_NONE;
694 }
695
696
697 jvmtiError
698 JvmtiEnvBase::get_owned_monitors(JavaThread *calling_thread, JavaThread* java_thread,
699 GrowableArray<jvmtiMonitorStackDepthInfo*> *owned_monitors_list) {
700 jvmtiError err = JVMTI_ERROR_NONE;
701 #ifdef ASSERT
702 uint32_t debug_bits = 0;
703 #endif
704 assert((SafepointSynchronize::is_at_safepoint() ||
705 is_thread_fully_suspended(java_thread, false, &debug_bits)),
706 "at safepoint or target thread is suspended");
707
708 if (java_thread->has_last_Java_frame()) {
709 ResourceMark rm;
710 HandleMark hm;
711 RegisterMap reg_map(java_thread);
712
713 int depth = 0;
714 for (javaVFrame *jvf = java_thread->last_java_vframe(®_map); jvf != NULL;
715 jvf = jvf->java_sender()) {
716 if (depth++ < MaxJavaStackTraceDepth) { // check for stack too deep
717 // add locked objects for this frame into list
718 err = get_locked_objects_in_frame(calling_thread, java_thread, jvf, owned_monitors_list, depth-1);
719 if (err != JVMTI_ERROR_NONE) {
720 return err;
721 }
722 }
723 }
724 }
725
726 // Get off stack monitors. (e.g. acquired via jni MonitorEnter).
727 JvmtiMonitorClosure jmc(java_thread, calling_thread, owned_monitors_list, this);
728 ObjectSynchronizer::monitors_iterate(&jmc);
729 err = jmc.error();
730
731 return err;
732 }
733
734 // Save JNI local handles for any objects that this frame owns.
735 jvmtiError
736 JvmtiEnvBase::get_locked_objects_in_frame(JavaThread* calling_thread, JavaThread* java_thread,
737 javaVFrame *jvf, GrowableArray<jvmtiMonitorStackDepthInfo*>* owned_monitors_list, int stack_depth) {
738 jvmtiError err = JVMTI_ERROR_NONE;
739 ResourceMark rm;
740
741 GrowableArray<MonitorInfo*>* mons = jvf->monitors();
742 if (mons->is_empty()) {
743 return err; // this javaVFrame holds no monitors
744 }
745
746 HandleMark hm;
747 oop wait_obj = NULL;
748 {
749 // save object of current wait() call (if any) for later comparison
750 ObjectMonitor *mon = java_thread->current_waiting_monitor();
751 if (mon != NULL) {
752 wait_obj = (oop)mon->object();
753 }
754 }
755 oop pending_obj = NULL;
756 {
757 // save object of current enter() call (if any) for later comparison
758 ObjectMonitor *mon = java_thread->current_pending_monitor();
759 if (mon != NULL) {
760 pending_obj = (oop)mon->object();
761 }
762 }
763
764 for (int i = 0; i < mons->length(); i++) {
765 MonitorInfo *mi = mons->at(i);
766
767 if (mi->owner_is_scalar_replaced()) continue;
768
769 oop obj = mi->owner();
770 if (obj == NULL) {
771 // this monitor doesn't have an owning object so skip it
772 continue;
773 }
774
775 if (wait_obj == obj) {
776 // the thread is waiting on this monitor so it isn't really owned
777 continue;
778 }
779
780 if (pending_obj == obj) {
781 // the thread is pending on this monitor so it isn't really owned
782 continue;
783 }
784
785 if (owned_monitors_list->length() > 0) {
786 // Our list has at least one object on it so we have to check
787 // for recursive object locking
788 bool found = false;
789 for (int j = 0; j < owned_monitors_list->length(); j++) {
790 jobject jobj = ((jvmtiMonitorStackDepthInfo*)owned_monitors_list->at(j))->monitor;
791 oop check = JNIHandles::resolve(jobj);
792 if (check == obj) {
793 found = true; // we found the object
794 break;
795 }
796 }
797
798 if (found) {
799 // already have this object so don't include it
800 continue;
801 }
802 }
803
804 // add the owning object to our list
805 jvmtiMonitorStackDepthInfo *jmsdi;
806 err = allocate(sizeof(jvmtiMonitorStackDepthInfo), (unsigned char **)&jmsdi);
807 if (err != JVMTI_ERROR_NONE) {
808 return err;
809 }
810 Handle hobj(obj);
811 jmsdi->monitor = jni_reference(calling_thread, hobj);
812 jmsdi->stack_depth = stack_depth;
813 owned_monitors_list->append(jmsdi);
814 }
815
816 return err;
817 }
818
819 jvmtiError
820 JvmtiEnvBase::get_stack_trace(JavaThread *java_thread,
821 jint start_depth, jint max_count,
822 jvmtiFrameInfo* frame_buffer, jint* count_ptr) {
823 #ifdef ASSERT
824 uint32_t debug_bits = 0;
825 #endif
826 assert((SafepointSynchronize::is_at_safepoint() ||
827 is_thread_fully_suspended(java_thread, false, &debug_bits)),
828 "at safepoint or target thread is suspended");
829 int count = 0;
830 if (java_thread->has_last_Java_frame()) {
831 RegisterMap reg_map(java_thread);
832 Thread* current_thread = Thread::current();
833 ResourceMark rm(current_thread);
834 javaVFrame *jvf = java_thread->last_java_vframe(®_map);
835 HandleMark hm(current_thread);
836 if (start_depth != 0) {
837 if (start_depth > 0) {
838 for (int j = 0; j < start_depth && jvf != NULL; j++) {
839 jvf = jvf->java_sender();
840 }
841 if (jvf == NULL) {
842 // start_depth is deeper than the stack depth
843 return JVMTI_ERROR_ILLEGAL_ARGUMENT;
844 }
845 } else { // start_depth < 0
846 // we are referencing the starting depth based on the oldest
847 // part of the stack.
848 // optimize to limit the number of times that java_sender() is called
849 javaVFrame *jvf_cursor = jvf;
850 javaVFrame *jvf_prev = NULL;
851 javaVFrame *jvf_prev_prev;
852 int j = 0;
853 while (jvf_cursor != NULL) {
854 jvf_prev_prev = jvf_prev;
855 jvf_prev = jvf_cursor;
856 for (j = 0; j > start_depth && jvf_cursor != NULL; j--) {
857 jvf_cursor = jvf_cursor->java_sender();
858 }
859 }
860 if (j == start_depth) {
861 // previous pointer is exactly where we want to start
862 jvf = jvf_prev;
863 } else {
864 // we need to back up further to get to the right place
865 if (jvf_prev_prev == NULL) {
866 // the -start_depth is greater than the stack depth
867 return JVMTI_ERROR_ILLEGAL_ARGUMENT;
868 }
869 // j now is the number of frames on the stack starting with
870 // jvf_prev, we start from jvf_prev_prev and move older on
871 // the stack that many, the result is -start_depth frames
872 // remaining.
873 jvf = jvf_prev_prev;
874 for (; j < 0; j++) {
875 jvf = jvf->java_sender();
876 }
877 }
878 }
879 }
880 for (; count < max_count && jvf != NULL; count++) {
881 frame_buffer[count].method = jvf->method()->jmethod_id();
882 frame_buffer[count].location = (jvf->method()->is_native() ? -1 : jvf->bci());
883 jvf = jvf->java_sender();
884 }
885 } else {
886 if (start_depth != 0) {
887 // no frames and there is a starting depth
888 return JVMTI_ERROR_ILLEGAL_ARGUMENT;
889 }
890 }
891 *count_ptr = count;
892 return JVMTI_ERROR_NONE;
893 }
894
895 jvmtiError
896 JvmtiEnvBase::get_frame_count(JvmtiThreadState *state, jint *count_ptr) {
897 assert((state != NULL),
898 "JavaThread should create JvmtiThreadState before calling this method");
899 *count_ptr = state->count_frames();
900 return JVMTI_ERROR_NONE;
901 }
902
903 jvmtiError
904 JvmtiEnvBase::get_frame_location(JavaThread *java_thread, jint depth,
905 jmethodID* method_ptr, jlocation* location_ptr) {
906 #ifdef ASSERT
907 uint32_t debug_bits = 0;
908 #endif
909 assert((SafepointSynchronize::is_at_safepoint() ||
910 is_thread_fully_suspended(java_thread, false, &debug_bits)),
911 "at safepoint or target thread is suspended");
912 Thread* current_thread = Thread::current();
913 ResourceMark rm(current_thread);
914
915 vframe *vf = vframeFor(java_thread, depth);
916 if (vf == NULL) {
917 return JVMTI_ERROR_NO_MORE_FRAMES;
918 }
919
920 // vframeFor should return a java frame. If it doesn't
921 // it means we've got an internal error and we return the
922 // error in product mode. In debug mode we will instead
923 // attempt to cast the vframe to a javaVFrame and will
924 // cause an assertion/crash to allow further diagnosis.
925 #ifdef PRODUCT
926 if (!vf->is_java_frame()) {
927 return JVMTI_ERROR_INTERNAL;
928 }
929 #endif
930
931 HandleMark hm(current_thread);
932 javaVFrame *jvf = javaVFrame::cast(vf);
933 methodOop method = jvf->method();
934 if (method->is_native()) {
935 *location_ptr = -1;
936 } else {
937 *location_ptr = jvf->bci();
938 }
939 *method_ptr = method->jmethod_id();
940
941 return JVMTI_ERROR_NONE;
942 }
943
944
945 jvmtiError
946 JvmtiEnvBase::get_object_monitor_usage(JavaThread* calling_thread, jobject object, jvmtiMonitorUsage* info_ptr) {
947 HandleMark hm;
948 Handle hobj;
949
950 bool at_safepoint = SafepointSynchronize::is_at_safepoint();
951
952 // Check arguments
953 {
954 oop mirror = JNIHandles::resolve_external_guard(object);
955 NULL_CHECK(mirror, JVMTI_ERROR_INVALID_OBJECT);
956 NULL_CHECK(info_ptr, JVMTI_ERROR_NULL_POINTER);
957
958 hobj = Handle(mirror);
959 }
960
961 JavaThread *owning_thread = NULL;
962 ObjectMonitor *mon = NULL;
963 jvmtiMonitorUsage ret = {
964 NULL, 0, 0, NULL, 0, NULL
965 };
966
967 uint32_t debug_bits = 0;
968 // first derive the object's owner and entry_count (if any)
969 {
970 // Revoke any biases before querying the mark word
971 if (SafepointSynchronize::is_at_safepoint()) {
972 BiasedLocking::revoke_at_safepoint(hobj);
973 } else {
974 BiasedLocking::revoke_and_rebias(hobj, false, calling_thread);
975 }
976
977 address owner = NULL;
978 {
979 markOop 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 // Since owning_thread_from_monitor_owner() grabs a lock, GC can
1005 // move our object at this point. However, our owner value is safe
1006 // since it is either the Lock word on a stack or a JavaThread *.
1007 owning_thread = Threads::owning_thread_from_monitor_owner(owner, !at_safepoint);
1008 assert(owning_thread != NULL, "sanity check");
1009 if (owning_thread != NULL) { // robustness
1010 // The monitor's owner either has to be the current thread, at safepoint
1011 // or it has to be suspended. Any of these conditions will prevent both
1012 // contending and waiting threads from modifying the state of
1013 // the monitor.
1014 if (!at_safepoint && !JvmtiEnv::is_thread_fully_suspended(owning_thread, true, &debug_bits)) {
1015 return JVMTI_ERROR_THREAD_NOT_SUSPENDED;
1016 }
1017 HandleMark hm;
1018 Handle th(owning_thread->threadObj());
1019 ret.owner = (jthread)jni_reference(calling_thread, th);
1020 }
1021 // implied else: no owner
1022 }
1023
1024 if (owning_thread != NULL) { // monitor is owned
1025 if ((address)owning_thread == owner) {
1026 // the owner field is the JavaThread *
1027 assert(mon != NULL,
1028 "must have heavyweight monitor with JavaThread * owner");
1029 ret.entry_count = mon->recursions() + 1;
1030 } else {
1031 // The owner field is the Lock word on the JavaThread's stack
1032 // so the recursions field is not valid. We have to count the
1033 // number of recursive monitor entries the hard way. We pass
1034 // a handle to survive any GCs along the way.
1035 ResourceMark rm;
1036 ret.entry_count = count_locked_objects(owning_thread, hobj);
1037 }
1038 }
1039 // implied else: entry_count == 0
1040 }
1041
1042 int nWant,nWait;
1043 if (mon != NULL) {
1044 // this object has a heavyweight monitor
1045 nWant = mon->contentions(); // # of threads contending for monitor
1046 nWait = mon->waiters(); // # of threads in Object.wait()
1047 ret.waiter_count = nWant + nWait;
1048 ret.notify_waiter_count = nWait;
1049 } else {
1050 // this object has a lightweight monitor
1051 ret.waiter_count = 0;
1052 ret.notify_waiter_count = 0;
1053 }
1054
1055 // Allocate memory for heavyweight and lightweight monitor.
1056 jvmtiError err;
1057 err = allocate(ret.waiter_count * sizeof(jthread *), (unsigned char**)&ret.waiters);
1058 if (err != JVMTI_ERROR_NONE) {
1059 return err;
1060 }
1061 err = allocate(ret.notify_waiter_count * sizeof(jthread *),
1062 (unsigned char**)&ret.notify_waiters);
1063 if (err != JVMTI_ERROR_NONE) {
1064 deallocate((unsigned char*)ret.waiters);
1065 return err;
1066 }
1067
1068 // now derive the rest of the fields
1069 if (mon != NULL) {
1070 // this object has a heavyweight monitor
1071
1072 // Number of waiters may actually be less than the waiter count.
1073 // So NULL out memory so that unused memory will be NULL.
1074 memset(ret.waiters, 0, ret.waiter_count * sizeof(jthread *));
1075 memset(ret.notify_waiters, 0, ret.notify_waiter_count * sizeof(jthread *));
1076
1077 if (ret.waiter_count > 0) {
1078 // we have contending and/or waiting threads
1079 HandleMark hm;
1080 if (nWant > 0) {
1081 // we have contending threads
1082 ResourceMark rm;
1083 // get_pending_threads returns only java thread so we do not need to
1084 // check for non java threads.
1085 GrowableArray<JavaThread*>* wantList = Threads::get_pending_threads(
1086 nWant, (address)mon, !at_safepoint);
1087 if (wantList->length() < nWant) {
1088 // robustness: the pending list has gotten smaller
1089 nWant = wantList->length();
1090 }
1091 for (int i = 0; i < nWant; i++) {
1092 JavaThread *pending_thread = wantList->at(i);
1093 // If the monitor has no owner, then a non-suspended contending
1094 // thread could potentially change the state of the monitor by
1095 // entering it. The JVM/TI spec doesn't allow this.
1096 if (owning_thread == NULL && !at_safepoint &
1097 !JvmtiEnv::is_thread_fully_suspended(pending_thread, true, &debug_bits)) {
1098 if (ret.owner != NULL) {
1099 destroy_jni_reference(calling_thread, ret.owner);
1100 }
1101 for (int j = 0; j < i; j++) {
1102 destroy_jni_reference(calling_thread, ret.waiters[j]);
1103 }
1104 deallocate((unsigned char*)ret.waiters);
1105 deallocate((unsigned char*)ret.notify_waiters);
1106 return JVMTI_ERROR_THREAD_NOT_SUSPENDED;
1107 }
1108 Handle th(pending_thread->threadObj());
1109 ret.waiters[i] = (jthread)jni_reference(calling_thread, th);
1110 }
1111 }
1112 if (nWait > 0) {
1113 // we have threads in Object.wait()
1114 int offset = nWant; // add after any contending threads
1115 ObjectWaiter *waiter = mon->first_waiter();
1116 for (int i = 0, j = 0; i < nWait; i++) {
1117 if (waiter == NULL) {
1118 // robustness: the waiting list has gotten smaller
1119 nWait = j;
1120 break;
1121 }
1122 Thread *t = mon->thread_of_waiter(waiter);
1123 if (t != NULL && t->is_Java_thread()) {
1124 JavaThread *wjava_thread = (JavaThread *)t;
1125 // If the thread was found on the ObjectWaiter list, then
1126 // it has not been notified. This thread can't change the
1127 // state of the monitor so it doesn't need to be suspended.
1128 Handle th(wjava_thread->threadObj());
1129 ret.waiters[offset + j] = (jthread)jni_reference(calling_thread, th);
1130 ret.notify_waiters[j++] = (jthread)jni_reference(calling_thread, th);
1131 }
1132 waiter = mon->next_waiter(waiter);
1133 }
1134 }
1135 }
1136
1137 // Adjust count. nWant and nWait count values may be less than original.
1138 ret.waiter_count = nWant + nWait;
1139 ret.notify_waiter_count = nWait;
1140 } else {
1141 // this object has a lightweight monitor and we have nothing more
1142 // to do here because the defaults are just fine.
1143 }
1144
1145 // we don't update return parameter unless everything worked
1146 *info_ptr = ret;
1147
1148 return JVMTI_ERROR_NONE;
1149 }
1150
1151 ResourceTracker::ResourceTracker(JvmtiEnv* env) {
1152 _env = env;
1153 _allocations = new (ResourceObj::C_HEAP) GrowableArray<unsigned char*>(20, true);
1154 _failed = false;
1155 }
1156 ResourceTracker::~ResourceTracker() {
1157 if (_failed) {
1158 for (int i=0; i<_allocations->length(); i++) {
1159 _env->deallocate(_allocations->at(i));
1160 }
1161 }
1162 delete _allocations;
1163 }
1164
1165 jvmtiError ResourceTracker::allocate(jlong size, unsigned char** mem_ptr) {
1166 unsigned char *ptr;
1167 jvmtiError err = _env->allocate(size, &ptr);
1168 if (err == JVMTI_ERROR_NONE) {
1169 _allocations->append(ptr);
1170 *mem_ptr = ptr;
1171 } else {
1172 *mem_ptr = NULL;
1173 _failed = true;
1174 }
1175 return err;
1176 }
1177
1178 unsigned char* ResourceTracker::allocate(jlong size) {
1179 unsigned char* ptr;
1180 allocate(size, &ptr);
1181 return ptr;
1182 }
1183
1184 char* ResourceTracker::strdup(const char* str) {
1185 char *dup_str = (char*)allocate(strlen(str)+1);
1186 if (dup_str != NULL) {
1187 strcpy(dup_str, str);
1188 }
1189 return dup_str;
1190 }
1191
1192 struct StackInfoNode {
1193 struct StackInfoNode *next;
1194 jvmtiStackInfo info;
1195 };
1196
1197 // Create a jvmtiStackInfo inside a linked list node and create a
1198 // buffer for the frame information, both allocated as resource objects.
1199 // Fill in both the jvmtiStackInfo and the jvmtiFrameInfo.
1200 // Note that either or both of thr and thread_oop
1201 // may be null if the thread is new or has exited.
1202 void
1203 VM_GetMultipleStackTraces::fill_frames(jthread jt, JavaThread *thr, oop thread_oop) {
1204 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
1205
1206 jint state = 0;
1207 struct StackInfoNode *node = NEW_RESOURCE_OBJ(struct StackInfoNode);
1208 jvmtiStackInfo *infop = &(node->info);
1209 node->next = head();
1210 set_head(node);
1211 infop->frame_count = 0;
1212 infop->thread = jt;
1213
1214 if (thread_oop != NULL) {
1215 // get most state bits
1216 state = (jint)java_lang_Thread::get_thread_status(thread_oop);
1217 }
1218
1219 if (thr != NULL) { // add more state bits if there is a JavaThead to query
1220 // same as is_being_ext_suspended() but without locking
1221 if (thr->is_ext_suspended() || thr->is_external_suspend()) {
1222 state |= JVMTI_THREAD_STATE_SUSPENDED;
1223 }
1224 JavaThreadState jts = thr->thread_state();
1225 if (jts == _thread_in_native) {
1226 state |= JVMTI_THREAD_STATE_IN_NATIVE;
1227 }
1228 OSThread* osThread = thr->osthread();
1229 if (osThread != NULL && osThread->interrupted()) {
1230 state |= JVMTI_THREAD_STATE_INTERRUPTED;
1231 }
1232 }
1233 infop->state = state;
1234
1235 if (thr != NULL || (state & JVMTI_THREAD_STATE_ALIVE) != 0) {
1236 infop->frame_buffer = NEW_RESOURCE_ARRAY(jvmtiFrameInfo, max_frame_count());
1237 env()->get_stack_trace(thr, 0, max_frame_count(),
1238 infop->frame_buffer, &(infop->frame_count));
1239 } else {
1240 infop->frame_buffer = NULL;
1241 infop->frame_count = 0;
1242 }
1243 _frame_count_total += infop->frame_count;
1244 }
1245
1246 // Based on the stack information in the linked list, allocate memory
1247 // block to return and fill it from the info in the linked list.
1248 void
1249 VM_GetMultipleStackTraces::allocate_and_fill_stacks(jint thread_count) {
1250 // do I need to worry about alignment issues?
1251 jlong alloc_size = thread_count * sizeof(jvmtiStackInfo)
1252 + _frame_count_total * sizeof(jvmtiFrameInfo);
1253 env()->allocate(alloc_size, (unsigned char **)&_stack_info);
1254
1255 // pointers to move through the newly allocated space as it is filled in
1256 jvmtiStackInfo *si = _stack_info + thread_count; // bottom of stack info
1257 jvmtiFrameInfo *fi = (jvmtiFrameInfo *)si; // is the top of frame info
1258
1259 // copy information in resource area into allocated buffer
1260 // insert stack info backwards since linked list is backwards
1261 // insert frame info forwards
1262 // walk the StackInfoNodes
1263 for (struct StackInfoNode *sin = head(); sin != NULL; sin = sin->next) {
1264 jint frame_count = sin->info.frame_count;
1265 size_t frames_size = frame_count * sizeof(jvmtiFrameInfo);
1266 --si;
1267 memcpy(si, &(sin->info), sizeof(jvmtiStackInfo));
1268 if (frames_size == 0) {
1269 si->frame_buffer = NULL;
1270 } else {
1271 memcpy(fi, sin->info.frame_buffer, frames_size);
1272 si->frame_buffer = fi; // point to the new allocated copy of the frames
1273 fi += frame_count;
1274 }
1275 }
1276 assert(si == _stack_info, "the last copied stack info must be the first record");
1277 assert((unsigned char *)fi == ((unsigned char *)_stack_info) + alloc_size,
1278 "the last copied frame info must be the last record");
1279 }
1280
1281
1282 void
1283 VM_GetThreadListStackTraces::doit() {
1284 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
1285
1286 ResourceMark rm;
1287 for (int i = 0; i < _thread_count; ++i) {
1288 jthread jt = _thread_list[i];
1289 oop thread_oop = JNIHandles::resolve_external_guard(jt);
1290 if (thread_oop == NULL || !thread_oop->is_a(SystemDictionary::Thread_klass())) {
1291 set_result(JVMTI_ERROR_INVALID_THREAD);
1292 return;
1293 }
1294 fill_frames(jt, java_lang_Thread::thread(thread_oop), thread_oop);
1295 }
1296 allocate_and_fill_stacks(_thread_count);
1297 }
1298
1299 void
1300 VM_GetAllStackTraces::doit() {
1301 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
1302
1303 ResourceMark rm;
1304 _final_thread_count = 0;
1305 for (JavaThread *jt = Threads::first(); jt != NULL; jt = jt->next()) {
1306 oop thread_oop = jt->threadObj();
1307 if (thread_oop != NULL &&
1308 !jt->is_exiting() &&
1309 java_lang_Thread::is_alive(thread_oop) &&
1310 !jt->is_hidden_from_external_view()) {
1311 ++_final_thread_count;
1312 // Handle block of the calling thread is used to create local refs.
1313 fill_frames((jthread)JNIHandles::make_local(_calling_thread, thread_oop),
1314 jt, thread_oop);
1315 }
1316 }
1317 allocate_and_fill_stacks(_final_thread_count);
1318 }
1319
1320 // Verifies that the top frame is a java frame in an expected state.
1321 // Deoptimizes frame if needed.
1322 // Checks that the frame method signature matches the return type (tos).
1323 // HandleMark must be defined in the caller only.
1324 // It is to keep a ret_ob_h handle alive after return to the caller.
1325 jvmtiError
1326 JvmtiEnvBase::check_top_frame(JavaThread* current_thread, JavaThread* java_thread,
1327 jvalue value, TosState tos, Handle* ret_ob_h) {
1328 ResourceMark rm(current_thread);
1329
1330 vframe *vf = vframeFor(java_thread, 0);
1331 NULL_CHECK(vf, JVMTI_ERROR_NO_MORE_FRAMES);
1332
1333 javaVFrame *jvf = (javaVFrame*) vf;
1334 if (!vf->is_java_frame() || jvf->method()->is_native()) {
1335 return JVMTI_ERROR_OPAQUE_FRAME;
1336 }
1337
1338 // If the frame is a compiled one, need to deoptimize it.
1339 if (vf->is_compiled_frame()) {
1340 if (!vf->fr().can_be_deoptimized()) {
1341 return JVMTI_ERROR_OPAQUE_FRAME;
1342 }
1343 Deoptimization::deoptimize_frame(java_thread, jvf->fr().id());
1344 }
1345
1346 // Get information about method return type
1347 Symbol* signature = jvf->method()->signature();
1348
1349 ResultTypeFinder rtf(signature);
1350 TosState fr_tos = as_TosState(rtf.type());
1351 if (fr_tos != tos) {
1352 if (tos != itos || (fr_tos != btos && fr_tos != ctos && fr_tos != stos)) {
1353 return JVMTI_ERROR_TYPE_MISMATCH;
1354 }
1355 }
1356
1357 // Check that the jobject class matches the return type signature.
1358 jobject jobj = value.l;
1359 if (tos == atos && jobj != NULL) { // NULL reference is allowed
1360 Handle ob_h = Handle(current_thread, JNIHandles::resolve_external_guard(jobj));
1361 NULL_CHECK(ob_h, JVMTI_ERROR_INVALID_OBJECT);
1362 KlassHandle ob_kh = KlassHandle(current_thread, ob_h()->klass());
1363 NULL_CHECK(ob_kh, JVMTI_ERROR_INVALID_OBJECT);
1364
1365 // Method return type signature.
1366 char* ty_sign = 1 + strchr(signature->as_C_string(), ')');
1367
1368 if (!VM_GetOrSetLocal::is_assignable(ty_sign, Klass::cast(ob_kh()), current_thread)) {
1369 return JVMTI_ERROR_TYPE_MISMATCH;
1370 }
1371 *ret_ob_h = ob_h;
1372 }
1373 return JVMTI_ERROR_NONE;
1374 } /* end check_top_frame */
1375
1376
1377 // ForceEarlyReturn<type> follows the PopFrame approach in many aspects.
1378 // Main difference is on the last stage in the interpreter.
1379 // The PopFrame stops method execution to continue execution
1380 // from the same method call instruction.
1381 // The ForceEarlyReturn forces return from method so the execution
1382 // continues at the bytecode following the method call.
1383
1384 // Threads_lock NOT held, java_thread not protected by lock
1385 // java_thread - pre-checked
1386
1387 jvmtiError
1388 JvmtiEnvBase::force_early_return(JavaThread* java_thread, jvalue value, TosState tos) {
1389 JavaThread* current_thread = JavaThread::current();
1390 HandleMark hm(current_thread);
1391 uint32_t debug_bits = 0;
1392
1393 // retrieve or create the state
1394 JvmtiThreadState* state = JvmtiThreadState::state_for(java_thread);
1395 if (state == NULL) {
1396 return JVMTI_ERROR_THREAD_NOT_ALIVE;
1397 }
1398
1399 // Check if java_thread is fully suspended
1400 if (!is_thread_fully_suspended(java_thread,
1401 true /* wait for suspend completion */,
1402 &debug_bits)) {
1403 return JVMTI_ERROR_THREAD_NOT_SUSPENDED;
1404 }
1405
1406 // Check to see if a ForceEarlyReturn was already in progress
1407 if (state->is_earlyret_pending()) {
1408 // Probably possible for JVMTI clients to trigger this, but the
1409 // JPDA backend shouldn't allow this to happen
1410 return JVMTI_ERROR_INTERNAL;
1411 }
1412 {
1413 // The same as for PopFrame. Workaround bug:
1414 // 4812902: popFrame hangs if the method is waiting at a synchronize
1415 // Catch this condition and return an error to avoid hanging.
1416 // Now JVMTI spec allows an implementation to bail out with an opaque
1417 // frame error.
1418 OSThread* osThread = java_thread->osthread();
1419 if (osThread->get_state() == MONITOR_WAIT) {
1420 return JVMTI_ERROR_OPAQUE_FRAME;
1421 }
1422 }
1423 Handle ret_ob_h = Handle();
1424 jvmtiError err = check_top_frame(current_thread, java_thread, value, tos, &ret_ob_h);
1425 if (err != JVMTI_ERROR_NONE) {
1426 return err;
1427 }
1428 assert(tos != atos || value.l == NULL || ret_ob_h() != NULL,
1429 "return object oop must not be NULL if jobject is not NULL");
1430
1431 // Update the thread state to reflect that the top frame must be
1432 // forced to return.
1433 // The current frame will be returned later when the suspended
1434 // thread is resumed and right before returning from VM to Java.
1435 // (see call_VM_base() in assembler_<cpu>.cpp).
1436
1437 state->set_earlyret_pending();
1438 state->set_earlyret_oop(ret_ob_h());
1439 state->set_earlyret_value(value, tos);
1440
1441 // Set pending step flag for this early return.
1442 // It is cleared when next step event is posted.
1443 state->set_pending_step_for_earlyret();
1444
1445 return JVMTI_ERROR_NONE;
1446 } /* end force_early_return */
1447
1448 void
1449 JvmtiMonitorClosure::do_monitor(ObjectMonitor* mon) {
1450 if ( _error != JVMTI_ERROR_NONE) {
1451 // Error occurred in previous iteration so no need to add
1452 // to the list.
1453 return;
1454 }
1455 if (mon->owner() == _java_thread ) {
1456 // Filter out on stack monitors collected during stack walk.
1457 oop obj = (oop)mon->object();
1458 bool found = false;
1459 for (int j = 0; j < _owned_monitors_list->length(); j++) {
1460 jobject jobj = ((jvmtiMonitorStackDepthInfo*)_owned_monitors_list->at(j))->monitor;
1461 oop check = JNIHandles::resolve(jobj);
1462 if (check == obj) {
1463 // On stack monitor already collected during the stack walk.
1464 found = true;
1465 break;
1466 }
1467 }
1468 if (found == false) {
1469 // This is off stack monitor (e.g. acquired via jni MonitorEnter).
1470 jvmtiError err;
1471 jvmtiMonitorStackDepthInfo *jmsdi;
1472 err = _env->allocate(sizeof(jvmtiMonitorStackDepthInfo), (unsigned char **)&jmsdi);
1473 if (err != JVMTI_ERROR_NONE) {
1474 _error = err;
1475 return;
1476 }
1477 Handle hobj(obj);
1478 jmsdi->monitor = _env->jni_reference(_calling_thread, hobj);
1479 // stack depth is unknown for this monitor.
1480 jmsdi->stack_depth = -1;
1481 _owned_monitors_list->append(jmsdi);
1482 }
1483 }
1484 }
1485
1486 #endif // !JVMTI_KERNEL