1 /*
2 * Copyright (c) 2003, 2010, 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/interfaceSupport.hpp"
39 #include "runtime/jfieldIDWorkaround.hpp"
40 #include "runtime/objectMonitor.hpp"
41 #include "runtime/objectMonitor.inline.hpp"
42 #include "runtime/signature.hpp"
43 #include "runtime/vframe.hpp"
44 #include "runtime/vframe_hp.hpp"
45 #include "runtime/vmThread.hpp"
46 #include "runtime/vm_operations.hpp"
47
48 ///////////////////////////////////////////////////////////////
49 //
50 // JvmtiEnvBase
51 //
52
53 JvmtiEnvBase* JvmtiEnvBase::_head_environment = NULL;
54
55 bool JvmtiEnvBase::_globally_initialized = false;
56 volatile bool JvmtiEnvBase::_needs_clean_up = false;
57
58 jvmtiPhase JvmtiEnvBase::_phase = JVMTI_PHASE_PRIMORDIAL;
59
60 volatile int JvmtiEnvBase::_dying_thread_env_iteration_count = 0;
61
62 extern jvmtiInterface_1_ jvmti_Interface;
63 extern jvmtiInterface_1_ jvmtiTrace_Interface;
64
65
66 // perform initializations that must occur before any JVMTI environments
67 // are released but which should only be initialized once (no matter
68 // how many environments are created).
69 void
70 JvmtiEnvBase::globally_initialize() {
71 assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(), "sanity check");
72 assert(_globally_initialized == false, "bad call");
73
74 JvmtiManageCapabilities::initialize();
75
76 #ifndef JVMTI_KERNEL
77 // register extension functions and events
78 JvmtiExtensions::register_extensions();
79 #endif // !JVMTI_KERNEL
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
164 JvmtiEnvBase::JvmtiEnvBase(jint version) : _env_event_enable() {
165 _version = version;
166 _env_local_storage = NULL;
167 _tag_map = NULL;
168 _native_method_prefix_count = 0;
169 _native_method_prefixes = NULL;
170 _next = NULL;
171 _class_file_load_hook_ever_enabled = false;
172
173 // Moot since ClassFileLoadHook not yet enabled.
174 // But "true" will give a more predictable ClassFileLoadHook behavior
175 // for environment creation during ClassFileLoadHook.
176 _is_retransformable = true;
177
178 // all callbacks initially NULL
179 memset(&_event_callbacks,0,sizeof(jvmtiEventCallbacks));
180
181 // all capabilities initially off
182 memset(&_current_capabilities, 0, sizeof(_current_capabilities));
183
184 // all prohibited capabilities initially off
185 memset(&_prohibited_capabilities, 0, sizeof(_prohibited_capabilities));
186
187 _magic = JVMTI_MAGIC;
188
189 JvmtiEventController::env_initialize((JvmtiEnv*)this);
190
191 #ifdef JVMTI_TRACE
192 _jvmti_external.functions = TraceJVMTI != NULL ? &jvmtiTrace_Interface : &jvmti_Interface;
193 #else
194 _jvmti_external.functions = &jvmti_Interface;
195 #endif
196 }
197
198
199 void
200 JvmtiEnvBase::dispose() {
201
202 #ifdef JVMTI_TRACE
203 JvmtiTrace::shutdown();
204 #endif
205
206 // Dispose of event info and let the event controller call us back
207 // in a locked state (env_dispose, below)
208 JvmtiEventController::env_dispose(this);
209 }
210
211 void
212 JvmtiEnvBase::env_dispose() {
213 assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(), "sanity check");
214
215 // We have been entered with all events disabled on this environment.
216 // A race to re-enable events (by setting callbacks) is prevented by
217 // checking for a valid environment when setting callbacks (while
218 // holding the JvmtiThreadState_lock).
219
220 // Mark as invalid.
221 _magic = DISPOSED_MAGIC;
222
223 // Relinquish all capabilities.
224 jvmtiCapabilities *caps = get_capabilities();
225 JvmtiManageCapabilities::relinquish_capabilities(caps, caps, caps);
226
227 // Same situation as with events (see above)
228 set_native_method_prefixes(0, NULL);
229
230 #ifndef JVMTI_KERNEL
231 JvmtiTagMap* tag_map_to_deallocate = _tag_map;
232 set_tag_map(NULL);
233 // A tag map can be big, deallocate it now
234 if (tag_map_to_deallocate != NULL) {
235 delete tag_map_to_deallocate;
236 }
237 #endif // !JVMTI_KERNEL
238
239 _needs_clean_up = true;
240 }
241
242
243 JvmtiEnvBase::~JvmtiEnvBase() {
244 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
245
246 // There is a small window of time during which the tag map of a
247 // disposed environment could have been reallocated.
248 // Make sure it is gone.
249 #ifndef JVMTI_KERNEL
250 JvmtiTagMap* tag_map_to_deallocate = _tag_map;
251 set_tag_map(NULL);
252 // A tag map can be big, deallocate it now
253 if (tag_map_to_deallocate != NULL) {
254 delete tag_map_to_deallocate;
255 }
256 #endif // !JVMTI_KERNEL
257
258 _magic = BAD_MAGIC;
259 }
260
261
262 void
263 JvmtiEnvBase::periodic_clean_up() {
264 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
265
266 // JvmtiEnvBase reference is saved in JvmtiEnvThreadState. So
267 // clean up JvmtiThreadState before deleting JvmtiEnv pointer.
268 JvmtiThreadState::periodic_clean_up();
269
270 // Unlink all invalid environments from the list of environments
271 // and deallocate them
272 JvmtiEnvIterator it;
273 JvmtiEnvBase* previous_env = NULL;
274 JvmtiEnvBase* env = it.first();
275 while (env != NULL) {
276 if (env->is_valid()) {
277 previous_env = env;
278 env = it.next(env);
279 } else {
280 // This one isn't valid, remove it from the list and deallocate it
281 JvmtiEnvBase* defunct_env = env;
282 env = it.next(env);
283 if (previous_env == NULL) {
284 _head_environment = env;
285 } else {
286 previous_env->set_next_environment(env);
287 }
288 delete defunct_env;
289 }
290 }
291
292 }
293
294
295 void
296 JvmtiEnvBase::check_for_periodic_clean_up() {
297 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
298
299 class ThreadInsideIterationClosure: public ThreadClosure {
300 private:
301 bool _inside;
302 public:
303 ThreadInsideIterationClosure() : _inside(false) {};
304
305 void do_thread(Thread* thread) {
306 _inside |= thread->is_inside_jvmti_env_iteration();
307 }
308
309 bool is_inside_jvmti_env_iteration() {
310 return _inside;
311 }
312 };
313
314 if (_needs_clean_up) {
315 // Check if we are currently iterating environment,
316 // deallocation should not occur if we are
317 ThreadInsideIterationClosure tiic;
318 Threads::threads_do(&tiic);
319 if (!tiic.is_inside_jvmti_env_iteration() &&
320 !is_inside_dying_thread_env_iteration()) {
321 _needs_clean_up = false;
322 JvmtiEnvBase::periodic_clean_up();
323 }
324 }
325 }
326
327
328 void
329 JvmtiEnvBase::record_first_time_class_file_load_hook_enabled() {
330 assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(),
331 "sanity check");
332
333 if (!_class_file_load_hook_ever_enabled) {
334 _class_file_load_hook_ever_enabled = true;
335
336 if (get_capabilities()->can_retransform_classes) {
337 _is_retransformable = true;
338 } else {
339 _is_retransformable = false;
340
341 // cannot add retransform capability after ClassFileLoadHook has been enabled
342 get_prohibited_capabilities()->can_retransform_classes = 1;
343 }
344 }
345 }
346
347
348 void
349 JvmtiEnvBase::record_class_file_load_hook_enabled() {
350 if (!_class_file_load_hook_ever_enabled) {
351 if (Threads::number_of_threads() == 0) {
352 record_first_time_class_file_load_hook_enabled();
353 } else {
354 MutexLocker mu(JvmtiThreadState_lock);
355 record_first_time_class_file_load_hook_enabled();
356 }
357 }
358 }
359
360
361 jvmtiError
362 JvmtiEnvBase::set_native_method_prefixes(jint prefix_count, char** prefixes) {
363 assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(),
364 "sanity check");
365
366 int old_prefix_count = get_native_method_prefix_count();
367 char **old_prefixes = get_native_method_prefixes();
368
369 // allocate and install the new prefixex
370 if (prefix_count == 0 || !is_valid()) {
371 _native_method_prefix_count = 0;
372 _native_method_prefixes = NULL;
373 } else {
374 // there are prefixes, allocate an array to hold them, and fill it
375 char** new_prefixes = (char**)os::malloc((prefix_count) * sizeof(char*));
376 if (new_prefixes == NULL) {
377 return JVMTI_ERROR_OUT_OF_MEMORY;
378 }
379 for (int i = 0; i < prefix_count; i++) {
380 char* prefix = prefixes[i];
381 if (prefix == NULL) {
382 for (int j = 0; j < (i-1); j++) {
383 os::free(new_prefixes[j]);
384 }
385 os::free(new_prefixes);
386 return JVMTI_ERROR_NULL_POINTER;
387 }
388 prefix = os::strdup(prefixes[i]);
389 if (prefix == NULL) {
390 for (int j = 0; j < (i-1); j++) {
391 os::free(new_prefixes[j]);
392 }
393 os::free(new_prefixes);
394 return JVMTI_ERROR_OUT_OF_MEMORY;
395 }
396 new_prefixes[i] = prefix;
397 }
398 _native_method_prefix_count = prefix_count;
399 _native_method_prefixes = new_prefixes;
400 }
401
402 // now that we know the new prefixes have been successfully installed we can
403 // safely remove the old ones
404 if (old_prefix_count != 0) {
405 for (int i = 0; i < old_prefix_count; i++) {
406 os::free(old_prefixes[i]);
407 }
408 os::free(old_prefixes);
409 }
410
411 return JVMTI_ERROR_NONE;
412 }
413
414
415 // Collect all the prefixes which have been set in any JVM TI environments
416 // by the SetNativeMethodPrefix(es) functions. Be sure to maintain the
417 // order of environments and the order of prefixes within each environment.
418 // Return in a resource allocated array.
419 char**
420 JvmtiEnvBase::get_all_native_method_prefixes(int* count_ptr) {
421 assert(Threads::number_of_threads() == 0 ||
422 SafepointSynchronize::is_at_safepoint() ||
423 JvmtiThreadState_lock->is_locked(),
424 "sanity check");
425
426 int total_count = 0;
427 GrowableArray<char*>* prefix_array =new GrowableArray<char*>(5);
428
429 JvmtiEnvIterator it;
430 for (JvmtiEnvBase* env = it.first(); env != NULL; env = it.next(env)) {
431 int prefix_count = env->get_native_method_prefix_count();
432 char** prefixes = env->get_native_method_prefixes();
433 for (int j = 0; j < prefix_count; j++) {
434 // retrieve a prefix and so that it is safe against asynchronous changes
435 // copy it into the resource area
436 char* prefix = prefixes[j];
437 char* prefix_copy = NEW_RESOURCE_ARRAY(char, strlen(prefix)+1);
438 strcpy(prefix_copy, prefix);
439 prefix_array->at_put_grow(total_count++, prefix_copy);
440 }
441 }
442
443 char** all_prefixes = NEW_RESOURCE_ARRAY(char*, total_count);
444 char** p = all_prefixes;
445 for (int i = 0; i < total_count; ++i) {
446 *p++ = prefix_array->at(i);
447 }
448 *count_ptr = total_count;
449 return all_prefixes;
450 }
451
452 void
453 JvmtiEnvBase::set_event_callbacks(const jvmtiEventCallbacks* callbacks,
454 jint size_of_callbacks) {
455 assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(), "sanity check");
456
457 size_t byte_cnt = sizeof(jvmtiEventCallbacks);
458
459 // clear in either case to be sure we got any gap between sizes
460 memset(&_event_callbacks, 0, byte_cnt);
461
462 // Now that JvmtiThreadState_lock is held, prevent a possible race condition where events
463 // are re-enabled by a call to set event callbacks where the DisposeEnvironment
464 // occurs after the boiler-plate environment check and before the lock is acquired.
465 if (callbacks != NULL && is_valid()) {
466 if (size_of_callbacks < (jint)byte_cnt) {
467 byte_cnt = size_of_callbacks;
468 }
469 memcpy(&_event_callbacks, callbacks, byte_cnt);
470 }
471 }
472
473 // Called from JVMTI entry points which perform stack walking. If the
474 // associated JavaThread is the current thread, then wait_for_suspend
475 // is not used. Otherwise, it determines if we should wait for the
476 // "other" thread to complete external suspension. (NOTE: in future
477 // releases the suspension mechanism should be reimplemented so this
478 // is not necessary.)
479 //
480 bool
481 JvmtiEnvBase::is_thread_fully_suspended(JavaThread* thr, bool wait_for_suspend, uint32_t *bits) {
482 // "other" threads require special handling
483 if (thr != JavaThread::current()) {
484 if (wait_for_suspend) {
485 // We are allowed to wait for the external suspend to complete
486 // so give the other thread a chance to get suspended.
487 if (!thr->wait_for_ext_suspend_completion(SuspendRetryCount,
488 SuspendRetryDelay, bits)) {
489 // didn't make it so let the caller know
490 return false;
491 }
492 }
493 // We aren't allowed to wait for the external suspend to complete
494 // so if the other thread isn't externally suspended we need to
495 // let the caller know.
496 else if (!thr->is_ext_suspend_completed_with_lock(bits)) {
497 return false;
498 }
499 }
500
501 return true;
502 }
503
504
505 // In the fullness of time, all users of the method should instead
506 // directly use allocate, besides being cleaner and faster, this will
507 // mean much better out of memory handling
508 unsigned char *
509 JvmtiEnvBase::jvmtiMalloc(jlong size) {
510 unsigned char* mem;
511 jvmtiError result = allocate(size, &mem);
512 assert(result == JVMTI_ERROR_NONE, "Allocate failed");
513 return mem;
514 }
515
516
517 //
518 // Threads
519 //
520
521 jobject *
522 JvmtiEnvBase::new_jobjectArray(int length, Handle *handles) {
523 if (length == 0) {
524 return NULL;
525 }
526
527 jobject *objArray = (jobject *) jvmtiMalloc(sizeof(jobject) * length);
528 NULL_CHECK(objArray, NULL);
529
530 for (int i=0; i<length; i++) {
531 objArray[i] = jni_reference(handles[i]);
532 }
533 return objArray;
534 }
535
536 jthread *
537 JvmtiEnvBase::new_jthreadArray(int length, Handle *handles) {
538 return (jthread *) new_jobjectArray(length,handles);
539 }
540
541 jthreadGroup *
542 JvmtiEnvBase::new_jthreadGroupArray(int length, Handle *handles) {
543 return (jthreadGroup *) new_jobjectArray(length,handles);
544 }
545
546
547 JavaThread *
548 JvmtiEnvBase::get_JavaThread(jthread jni_thread) {
549 oop t = JNIHandles::resolve_external_guard(jni_thread);
550 if (t == NULL || !t->is_a(SystemDictionary::Thread_klass())) {
551 return NULL;
552 }
553 // The following returns NULL if the thread has not yet run or is in
554 // process of exiting
555 return java_lang_Thread::thread(t);
556 }
557
558
559 // update the access_flags for the field in the klass
560 void
561 JvmtiEnvBase::update_klass_field_access_flag(fieldDescriptor *fd) {
562 instanceKlass* ik = instanceKlass::cast(fd->field_holder());
563 typeArrayOop fields = ik->fields();
564 fields->ushort_at_put(fd->index(), (jushort)fd->access_flags().as_short());
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 int offset = id->offset();
611 klassOop holder = id->holder();
612 found = instanceKlass::cast(holder)->find_local_field_from_offset(offset, true, fd);
613 } else {
614 // Non-static field. The fieldID is really the offset of the field within the object.
615 int offset = jfieldIDWorkaround::from_instance_jfieldID(k, field);
616 found = instanceKlass::cast(k)->find_field_from_offset(offset, false, fd);
617 }
618 return found;
619 }
620
621 //
622 // Object Monitor Information
623 //
624
625 //
626 // Count the number of objects for a lightweight monitor. The hobj
627 // parameter is object that owns the monitor so this routine will
628 // count the number of times the same object was locked by frames
629 // in java_thread.
630 //
631 jint
632 JvmtiEnvBase::count_locked_objects(JavaThread *java_thread, Handle hobj) {
633 jint ret = 0;
634 if (!java_thread->has_last_Java_frame()) {
635 return ret; // no Java frames so no monitors
636 }
637
638 ResourceMark rm;
639 HandleMark hm;
640 RegisterMap reg_map(java_thread);
641
642 for(javaVFrame *jvf=java_thread->last_java_vframe(®_map); jvf != NULL;
643 jvf = jvf->java_sender()) {
644 GrowableArray<MonitorInfo*>* mons = jvf->monitors();
645 if (!mons->is_empty()) {
646 for (int i = 0; i < mons->length(); i++) {
647 MonitorInfo *mi = mons->at(i);
648 if (mi->owner_is_scalar_replaced()) continue;
649
650 // see if owner of the monitor is our object
651 if (mi->owner() != NULL && mi->owner() == hobj()) {
652 ret++;
653 }
654 }
655 }
656 }
657 return ret;
658 }
659
660
661
662 jvmtiError
663 JvmtiEnvBase::get_current_contended_monitor(JavaThread *calling_thread, JavaThread *java_thread, jobject *monitor_ptr) {
664 #ifdef ASSERT
665 uint32_t debug_bits = 0;
666 #endif
667 assert((SafepointSynchronize::is_at_safepoint() ||
668 is_thread_fully_suspended(java_thread, false, &debug_bits)),
669 "at safepoint or target thread is suspended");
670 oop obj = NULL;
671 ObjectMonitor *mon = java_thread->current_waiting_monitor();
672 if (mon == NULL) {
673 // thread is not doing an Object.wait() call
674 mon = java_thread->current_pending_monitor();
675 if (mon != NULL) {
676 // The thread is trying to enter() or raw_enter() an ObjectMonitor.
677 obj = (oop)mon->object();
678 // If obj == NULL, then ObjectMonitor is raw which doesn't count
679 // as contended for this API
680 }
681 // implied else: no contended ObjectMonitor
682 } else {
683 // thread is doing an Object.wait() call
684 obj = (oop)mon->object();
685 assert(obj != NULL, "Object.wait() should have an object");
686 }
687
688 if (obj == NULL) {
689 *monitor_ptr = NULL;
690 } else {
691 HandleMark hm;
692 Handle hobj(obj);
693 *monitor_ptr = jni_reference(calling_thread, hobj);
694 }
695 return JVMTI_ERROR_NONE;
696 }
697
698
699 jvmtiError
700 JvmtiEnvBase::get_owned_monitors(JavaThread *calling_thread, JavaThread* java_thread,
701 GrowableArray<jvmtiMonitorStackDepthInfo*> *owned_monitors_list) {
702 jvmtiError err = JVMTI_ERROR_NONE;
703 #ifdef ASSERT
704 uint32_t debug_bits = 0;
705 #endif
706 assert((SafepointSynchronize::is_at_safepoint() ||
707 is_thread_fully_suspended(java_thread, false, &debug_bits)),
708 "at safepoint or target thread is suspended");
709
710 if (java_thread->has_last_Java_frame()) {
711 ResourceMark rm;
712 HandleMark hm;
713 RegisterMap reg_map(java_thread);
714
715 int depth = 0;
716 for (javaVFrame *jvf = java_thread->last_java_vframe(®_map); jvf != NULL;
717 jvf = jvf->java_sender()) {
718 if (depth++ < MaxJavaStackTraceDepth) { // check for stack too deep
719 // add locked objects for this frame into list
720 err = get_locked_objects_in_frame(calling_thread, java_thread, jvf, owned_monitors_list, depth-1);
721 if (err != JVMTI_ERROR_NONE) {
722 return err;
723 }
724 }
725 }
726 }
727
728 // Get off stack monitors. (e.g. acquired via jni MonitorEnter).
729 JvmtiMonitorClosure jmc(java_thread, calling_thread, owned_monitors_list, this);
730 ObjectSynchronizer::monitors_iterate(&jmc);
731 err = jmc.error();
732
733 return err;
734 }
735
736 // Save JNI local handles for any objects that this frame owns.
737 jvmtiError
738 JvmtiEnvBase::get_locked_objects_in_frame(JavaThread* calling_thread, JavaThread* java_thread,
739 javaVFrame *jvf, GrowableArray<jvmtiMonitorStackDepthInfo*>* owned_monitors_list, int stack_depth) {
740 jvmtiError err = JVMTI_ERROR_NONE;
741 ResourceMark rm;
742
743 GrowableArray<MonitorInfo*>* mons = jvf->monitors();
744 if (mons->is_empty()) {
745 return err; // this javaVFrame holds no monitors
746 }
747
748 HandleMark hm;
749 oop wait_obj = NULL;
750 {
751 // save object of current wait() call (if any) for later comparison
752 ObjectMonitor *mon = java_thread->current_waiting_monitor();
753 if (mon != NULL) {
754 wait_obj = (oop)mon->object();
755 }
756 }
757 oop pending_obj = NULL;
758 {
759 // save object of current enter() call (if any) for later comparison
760 ObjectMonitor *mon = java_thread->current_pending_monitor();
761 if (mon != NULL) {
762 pending_obj = (oop)mon->object();
763 }
764 }
765
766 for (int i = 0; i < mons->length(); i++) {
767 MonitorInfo *mi = mons->at(i);
768
769 if (mi->owner_is_scalar_replaced()) continue;
770
771 oop obj = mi->owner();
772 if (obj == NULL) {
773 // this monitor doesn't have an owning object so skip it
774 continue;
775 }
776
777 if (wait_obj == obj) {
778 // the thread is waiting on this monitor so it isn't really owned
779 continue;
780 }
781
782 if (pending_obj == obj) {
783 // the thread is pending on this monitor so it isn't really owned
784 continue;
785 }
786
787 if (owned_monitors_list->length() > 0) {
788 // Our list has at least one object on it so we have to check
789 // for recursive object locking
790 bool found = false;
791 for (int j = 0; j < owned_monitors_list->length(); j++) {
792 jobject jobj = ((jvmtiMonitorStackDepthInfo*)owned_monitors_list->at(j))->monitor;
793 oop check = JNIHandles::resolve(jobj);
794 if (check == obj) {
795 found = true; // we found the object
796 break;
797 }
798 }
799
800 if (found) {
801 // already have this object so don't include it
802 continue;
803 }
804 }
805
806 // add the owning object to our list
807 jvmtiMonitorStackDepthInfo *jmsdi;
808 err = allocate(sizeof(jvmtiMonitorStackDepthInfo), (unsigned char **)&jmsdi);
809 if (err != JVMTI_ERROR_NONE) {
810 return err;
811 }
812 Handle hobj(obj);
813 jmsdi->monitor = jni_reference(calling_thread, hobj);
814 jmsdi->stack_depth = stack_depth;
815 owned_monitors_list->append(jmsdi);
816 }
817
818 return err;
819 }
820
821 jvmtiError
822 JvmtiEnvBase::get_stack_trace(JavaThread *java_thread,
823 jint start_depth, jint max_count,
824 jvmtiFrameInfo* frame_buffer, jint* count_ptr) {
825 #ifdef ASSERT
826 uint32_t debug_bits = 0;
827 #endif
828 assert((SafepointSynchronize::is_at_safepoint() ||
829 is_thread_fully_suspended(java_thread, false, &debug_bits)),
830 "at safepoint or target thread is suspended");
831 int count = 0;
832 if (java_thread->has_last_Java_frame()) {
833 RegisterMap reg_map(java_thread);
834 Thread* current_thread = Thread::current();
835 ResourceMark rm(current_thread);
836 javaVFrame *jvf = java_thread->last_java_vframe(®_map);
837 HandleMark hm(current_thread);
838 if (start_depth != 0) {
839 if (start_depth > 0) {
840 for (int j = 0; j < start_depth && jvf != NULL; j++) {
841 jvf = jvf->java_sender();
842 }
843 if (jvf == NULL) {
844 // start_depth is deeper than the stack depth
845 return JVMTI_ERROR_ILLEGAL_ARGUMENT;
846 }
847 } else { // start_depth < 0
848 // we are referencing the starting depth based on the oldest
849 // part of the stack.
850 // optimize to limit the number of times that java_sender() is called
851 javaVFrame *jvf_cursor = jvf;
852 javaVFrame *jvf_prev = NULL;
853 javaVFrame *jvf_prev_prev;
854 int j = 0;
855 while (jvf_cursor != NULL) {
856 jvf_prev_prev = jvf_prev;
857 jvf_prev = jvf_cursor;
858 for (j = 0; j > start_depth && jvf_cursor != NULL; j--) {
859 jvf_cursor = jvf_cursor->java_sender();
860 }
861 }
862 if (j == start_depth) {
863 // previous pointer is exactly where we want to start
864 jvf = jvf_prev;
865 } else {
866 // we need to back up further to get to the right place
867 if (jvf_prev_prev == NULL) {
868 // the -start_depth is greater than the stack depth
869 return JVMTI_ERROR_ILLEGAL_ARGUMENT;
870 }
871 // j now is the number of frames on the stack starting with
872 // jvf_prev, we start from jvf_prev_prev and move older on
873 // the stack that many, the result is -start_depth frames
874 // remaining.
875 jvf = jvf_prev_prev;
876 for (; j < 0; j++) {
877 jvf = jvf->java_sender();
878 }
879 }
880 }
881 }
882 for (; count < max_count && jvf != NULL; count++) {
883 frame_buffer[count].method = jvf->method()->jmethod_id();
884 frame_buffer[count].location = (jvf->method()->is_native() ? -1 : jvf->bci());
885 jvf = jvf->java_sender();
886 }
887 } else {
888 if (start_depth != 0) {
889 // no frames and there is a starting depth
890 return JVMTI_ERROR_ILLEGAL_ARGUMENT;
891 }
892 }
893 *count_ptr = count;
894 return JVMTI_ERROR_NONE;
895 }
896
897 jvmtiError
898 JvmtiEnvBase::get_frame_count(JvmtiThreadState *state, jint *count_ptr) {
899 assert((state != NULL),
900 "JavaThread should create JvmtiThreadState before calling this method");
901 *count_ptr = state->count_frames();
902 return JVMTI_ERROR_NONE;
903 }
904
905 jvmtiError
906 JvmtiEnvBase::get_frame_location(JavaThread *java_thread, jint depth,
907 jmethodID* method_ptr, jlocation* location_ptr) {
908 #ifdef ASSERT
909 uint32_t debug_bits = 0;
910 #endif
911 assert((SafepointSynchronize::is_at_safepoint() ||
912 is_thread_fully_suspended(java_thread, false, &debug_bits)),
913 "at safepoint or target thread is suspended");
914 Thread* current_thread = Thread::current();
915 ResourceMark rm(current_thread);
916
917 vframe *vf = vframeFor(java_thread, depth);
918 if (vf == NULL) {
919 return JVMTI_ERROR_NO_MORE_FRAMES;
920 }
921
922 // vframeFor should return a java frame. If it doesn't
923 // it means we've got an internal error and we return the
924 // error in product mode. In debug mode we will instead
925 // attempt to cast the vframe to a javaVFrame and will
926 // cause an assertion/crash to allow further diagnosis.
927 #ifdef PRODUCT
928 if (!vf->is_java_frame()) {
929 return JVMTI_ERROR_INTERNAL;
930 }
931 #endif
932
933 HandleMark hm(current_thread);
934 javaVFrame *jvf = javaVFrame::cast(vf);
935 methodOop method = jvf->method();
936 if (method->is_native()) {
937 *location_ptr = -1;
938 } else {
939 *location_ptr = jvf->bci();
940 }
941 *method_ptr = method->jmethod_id();
942
943 return JVMTI_ERROR_NONE;
944 }
945
946
947 jvmtiError
948 JvmtiEnvBase::get_object_monitor_usage(JavaThread* calling_thread, jobject object, jvmtiMonitorUsage* info_ptr) {
949 HandleMark hm;
950 Handle hobj;
951
952 bool at_safepoint = SafepointSynchronize::is_at_safepoint();
953
954 // Check arguments
955 {
956 oop mirror = JNIHandles::resolve_external_guard(object);
957 NULL_CHECK(mirror, JVMTI_ERROR_INVALID_OBJECT);
958 NULL_CHECK(info_ptr, JVMTI_ERROR_NULL_POINTER);
959
960 hobj = Handle(mirror);
961 }
962
963 JavaThread *owning_thread = NULL;
964 ObjectMonitor *mon = NULL;
965 jvmtiMonitorUsage ret = {
966 NULL, 0, 0, NULL, 0, NULL
967 };
968
969 uint32_t debug_bits = 0;
970 // first derive the object's owner and entry_count (if any)
971 {
972 // Revoke any biases before querying the mark word
973 if (SafepointSynchronize::is_at_safepoint()) {
974 BiasedLocking::revoke_at_safepoint(hobj);
975 } else {
976 BiasedLocking::revoke_and_rebias(hobj, false, calling_thread);
977 }
978
979 address owner = NULL;
980 {
981 markOop mark = hobj()->mark();
982
983 if (!mark->has_monitor()) {
984 // this object has a lightweight monitor
985
986 if (mark->has_locker()) {
987 owner = (address)mark->locker(); // save the address of the Lock word
988 }
989 // implied else: no owner
990 } else {
991 // this object has a heavyweight monitor
992 mon = mark->monitor();
993
994 // The owner field of a heavyweight monitor may be NULL for no
995 // owner, a JavaThread * or it may still be the address of the
996 // Lock word in a JavaThread's stack. A monitor can be inflated
997 // by a non-owning JavaThread, but only the owning JavaThread
998 // can change the owner field from the Lock word to the
999 // JavaThread * and it may not have done that yet.
1000 owner = (address)mon->owner();
1001 }
1002 }
1003
1004 if (owner != NULL) {
1005 // This monitor is owned so we have to find the owning JavaThread.
1006 // Since owning_thread_from_monitor_owner() grabs a lock, GC can
1007 // move our object at this point. However, our owner value is safe
1008 // since it is either the Lock word on a stack or a JavaThread *.
1009 owning_thread = Threads::owning_thread_from_monitor_owner(owner, !at_safepoint);
1010 assert(owning_thread != NULL, "sanity check");
1011 if (owning_thread != NULL) { // robustness
1012 // The monitor's owner either has to be the current thread, at safepoint
1013 // or it has to be suspended. Any of these conditions will prevent both
1014 // contending and waiting threads from modifying the state of
1015 // the monitor.
1016 if (!at_safepoint && !JvmtiEnv::is_thread_fully_suspended(owning_thread, true, &debug_bits)) {
1017 return JVMTI_ERROR_THREAD_NOT_SUSPENDED;
1018 }
1019 HandleMark hm;
1020 Handle th(owning_thread->threadObj());
1021 ret.owner = (jthread)jni_reference(calling_thread, th);
1022 }
1023 // implied else: no owner
1024 }
1025
1026 if (owning_thread != NULL) { // monitor is owned
1027 if ((address)owning_thread == owner) {
1028 // the owner field is the JavaThread *
1029 assert(mon != NULL,
1030 "must have heavyweight monitor with JavaThread * owner");
1031 ret.entry_count = mon->recursions() + 1;
1032 } else {
1033 // The owner field is the Lock word on the JavaThread's stack
1034 // so the recursions field is not valid. We have to count the
1035 // number of recursive monitor entries the hard way. We pass
1036 // a handle to survive any GCs along the way.
1037 ResourceMark rm;
1038 ret.entry_count = count_locked_objects(owning_thread, hobj);
1039 }
1040 }
1041 // implied else: entry_count == 0
1042 }
1043
1044 int nWant,nWait;
1045 if (mon != NULL) {
1046 // this object has a heavyweight monitor
1047 nWant = mon->contentions(); // # of threads contending for monitor
1048 nWait = mon->waiters(); // # of threads in Object.wait()
1049 ret.waiter_count = nWant + nWait;
1050 ret.notify_waiter_count = nWait;
1051 } else {
1052 // this object has a lightweight monitor
1053 ret.waiter_count = 0;
1054 ret.notify_waiter_count = 0;
1055 }
1056
1057 // Allocate memory for heavyweight and lightweight monitor.
1058 jvmtiError err;
1059 err = allocate(ret.waiter_count * sizeof(jthread *), (unsigned char**)&ret.waiters);
1060 if (err != JVMTI_ERROR_NONE) {
1061 return err;
1062 }
1063 err = allocate(ret.notify_waiter_count * sizeof(jthread *),
1064 (unsigned char**)&ret.notify_waiters);
1065 if (err != JVMTI_ERROR_NONE) {
1066 deallocate((unsigned char*)ret.waiters);
1067 return err;
1068 }
1069
1070 // now derive the rest of the fields
1071 if (mon != NULL) {
1072 // this object has a heavyweight monitor
1073
1074 // Number of waiters may actually be less than the waiter count.
1075 // So NULL out memory so that unused memory will be NULL.
1076 memset(ret.waiters, 0, ret.waiter_count * sizeof(jthread *));
1077 memset(ret.notify_waiters, 0, ret.notify_waiter_count * sizeof(jthread *));
1078
1079 if (ret.waiter_count > 0) {
1080 // we have contending and/or waiting threads
1081 HandleMark hm;
1082 if (nWant > 0) {
1083 // we have contending threads
1084 ResourceMark rm;
1085 // get_pending_threads returns only java thread so we do not need to
1086 // check for non java threads.
1087 GrowableArray<JavaThread*>* wantList = Threads::get_pending_threads(
1088 nWant, (address)mon, !at_safepoint);
1089 if (wantList->length() < nWant) {
1090 // robustness: the pending list has gotten smaller
1091 nWant = wantList->length();
1092 }
1093 for (int i = 0; i < nWant; i++) {
1094 JavaThread *pending_thread = wantList->at(i);
1095 // If the monitor has no owner, then a non-suspended contending
1096 // thread could potentially change the state of the monitor by
1097 // entering it. The JVM/TI spec doesn't allow this.
1098 if (owning_thread == NULL && !at_safepoint &
1099 !JvmtiEnv::is_thread_fully_suspended(pending_thread, true, &debug_bits)) {
1100 if (ret.owner != NULL) {
1101 destroy_jni_reference(calling_thread, ret.owner);
1102 }
1103 for (int j = 0; j < i; j++) {
1104 destroy_jni_reference(calling_thread, ret.waiters[j]);
1105 }
1106 deallocate((unsigned char*)ret.waiters);
1107 deallocate((unsigned char*)ret.notify_waiters);
1108 return JVMTI_ERROR_THREAD_NOT_SUSPENDED;
1109 }
1110 Handle th(pending_thread->threadObj());
1111 ret.waiters[i] = (jthread)jni_reference(calling_thread, th);
1112 }
1113 }
1114 if (nWait > 0) {
1115 // we have threads in Object.wait()
1116 int offset = nWant; // add after any contending threads
1117 ObjectWaiter *waiter = mon->first_waiter();
1118 for (int i = 0, j = 0; i < nWait; i++) {
1119 if (waiter == NULL) {
1120 // robustness: the waiting list has gotten smaller
1121 nWait = j;
1122 break;
1123 }
1124 Thread *t = mon->thread_of_waiter(waiter);
1125 if (t != NULL && t->is_Java_thread()) {
1126 JavaThread *wjava_thread = (JavaThread *)t;
1127 // If the thread was found on the ObjectWaiter list, then
1128 // it has not been notified. This thread can't change the
1129 // state of the monitor so it doesn't need to be suspended.
1130 Handle th(wjava_thread->threadObj());
1131 ret.waiters[offset + j] = (jthread)jni_reference(calling_thread, th);
1132 ret.notify_waiters[j++] = (jthread)jni_reference(calling_thread, th);
1133 }
1134 waiter = mon->next_waiter(waiter);
1135 }
1136 }
1137 }
1138
1139 // Adjust count. nWant and nWait count values may be less than original.
1140 ret.waiter_count = nWant + nWait;
1141 ret.notify_waiter_count = nWait;
1142 } else {
1143 // this object has a lightweight monitor and we have nothing more
1144 // to do here because the defaults are just fine.
1145 }
1146
1147 // we don't update return parameter unless everything worked
1148 *info_ptr = ret;
1149
1150 return JVMTI_ERROR_NONE;
1151 }
1152
1153 ResourceTracker::ResourceTracker(JvmtiEnv* env) {
1154 _env = env;
1155 _allocations = new (ResourceObj::C_HEAP) GrowableArray<unsigned char*>(20, true);
1156 _failed = false;
1157 }
1158 ResourceTracker::~ResourceTracker() {
1159 if (_failed) {
1160 for (int i=0; i<_allocations->length(); i++) {
1161 _env->deallocate(_allocations->at(i));
1162 }
1163 }
1164 delete _allocations;
1165 }
1166
1167 jvmtiError ResourceTracker::allocate(jlong size, unsigned char** mem_ptr) {
1168 unsigned char *ptr;
1169 jvmtiError err = _env->allocate(size, &ptr);
1170 if (err == JVMTI_ERROR_NONE) {
1171 _allocations->append(ptr);
1172 *mem_ptr = ptr;
1173 } else {
1174 *mem_ptr = NULL;
1175 _failed = true;
1176 }
1177 return err;
1178 }
1179
1180 unsigned char* ResourceTracker::allocate(jlong size) {
1181 unsigned char* ptr;
1182 allocate(size, &ptr);
1183 return ptr;
1184 }
1185
1186 char* ResourceTracker::strdup(const char* str) {
1187 char *dup_str = (char*)allocate(strlen(str)+1);
1188 if (dup_str != NULL) {
1189 strcpy(dup_str, str);
1190 }
1191 return dup_str;
1192 }
1193
1194 struct StackInfoNode {
1195 struct StackInfoNode *next;
1196 jvmtiStackInfo info;
1197 };
1198
1199 // Create a jvmtiStackInfo inside a linked list node and create a
1200 // buffer for the frame information, both allocated as resource objects.
1201 // Fill in both the jvmtiStackInfo and the jvmtiFrameInfo.
1202 // Note that either or both of thr and thread_oop
1203 // may be null if the thread is new or has exited.
1204 void
1205 VM_GetMultipleStackTraces::fill_frames(jthread jt, JavaThread *thr, oop thread_oop) {
1206 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
1207
1208 jint state = 0;
1209 struct StackInfoNode *node = NEW_RESOURCE_OBJ(struct StackInfoNode);
1210 jvmtiStackInfo *infop = &(node->info);
1211 node->next = head();
1212 set_head(node);
1213 infop->frame_count = 0;
1214 infop->thread = jt;
1215
1216 if (thread_oop != NULL) {
1217 // get most state bits
1218 state = (jint)java_lang_Thread::get_thread_status(thread_oop);
1219 }
1220
1221 if (thr != NULL) { // add more state bits if there is a JavaThead to query
1222 // same as is_being_ext_suspended() but without locking
1223 if (thr->is_ext_suspended() || thr->is_external_suspend()) {
1224 state |= JVMTI_THREAD_STATE_SUSPENDED;
1225 }
1226 JavaThreadState jts = thr->thread_state();
1227 if (jts == _thread_in_native) {
1228 state |= JVMTI_THREAD_STATE_IN_NATIVE;
1229 }
1230 OSThread* osThread = thr->osthread();
1231 if (osThread != NULL && osThread->interrupted()) {
1232 state |= JVMTI_THREAD_STATE_INTERRUPTED;
1233 }
1234 }
1235 infop->state = state;
1236
1237 if (thr != NULL || (state & JVMTI_THREAD_STATE_ALIVE) != 0) {
1238 infop->frame_buffer = NEW_RESOURCE_ARRAY(jvmtiFrameInfo, max_frame_count());
1239 env()->get_stack_trace(thr, 0, max_frame_count(),
1240 infop->frame_buffer, &(infop->frame_count));
1241 } else {
1242 infop->frame_buffer = NULL;
1243 infop->frame_count = 0;
1244 }
1245 _frame_count_total += infop->frame_count;
1246 }
1247
1248 // Based on the stack information in the linked list, allocate memory
1249 // block to return and fill it from the info in the linked list.
1250 void
1251 VM_GetMultipleStackTraces::allocate_and_fill_stacks(jint thread_count) {
1252 // do I need to worry about alignment issues?
1253 jlong alloc_size = thread_count * sizeof(jvmtiStackInfo)
1254 + _frame_count_total * sizeof(jvmtiFrameInfo);
1255 env()->allocate(alloc_size, (unsigned char **)&_stack_info);
1256
1257 // pointers to move through the newly allocated space as it is filled in
1258 jvmtiStackInfo *si = _stack_info + thread_count; // bottom of stack info
1259 jvmtiFrameInfo *fi = (jvmtiFrameInfo *)si; // is the top of frame info
1260
1261 // copy information in resource area into allocated buffer
1262 // insert stack info backwards since linked list is backwards
1263 // insert frame info forwards
1264 // walk the StackInfoNodes
1265 for (struct StackInfoNode *sin = head(); sin != NULL; sin = sin->next) {
1266 jint frame_count = sin->info.frame_count;
1267 size_t frames_size = frame_count * sizeof(jvmtiFrameInfo);
1268 --si;
1269 memcpy(si, &(sin->info), sizeof(jvmtiStackInfo));
1270 if (frames_size == 0) {
1271 si->frame_buffer = NULL;
1272 } else {
1273 memcpy(fi, sin->info.frame_buffer, frames_size);
1274 si->frame_buffer = fi; // point to the new allocated copy of the frames
1275 fi += frame_count;
1276 }
1277 }
1278 assert(si == _stack_info, "the last copied stack info must be the first record");
1279 assert((unsigned char *)fi == ((unsigned char *)_stack_info) + alloc_size,
1280 "the last copied frame info must be the last record");
1281 }
1282
1283
1284 void
1285 VM_GetThreadListStackTraces::doit() {
1286 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
1287
1288 ResourceMark rm;
1289 for (int i = 0; i < _thread_count; ++i) {
1290 jthread jt = _thread_list[i];
1291 oop thread_oop = JNIHandles::resolve_external_guard(jt);
1292 if (thread_oop == NULL || !thread_oop->is_a(SystemDictionary::Thread_klass())) {
1293 set_result(JVMTI_ERROR_INVALID_THREAD);
1294 return;
1295 }
1296 fill_frames(jt, java_lang_Thread::thread(thread_oop), thread_oop);
1297 }
1298 allocate_and_fill_stacks(_thread_count);
1299 }
1300
1301 void
1302 VM_GetAllStackTraces::doit() {
1303 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
1304
1305 ResourceMark rm;
1306 _final_thread_count = 0;
1307 for (JavaThread *jt = Threads::first(); jt != NULL; jt = jt->next()) {
1308 oop thread_oop = jt->threadObj();
1309 if (thread_oop != NULL &&
1310 !jt->is_exiting() &&
1311 java_lang_Thread::is_alive(thread_oop) &&
1312 !jt->is_hidden_from_external_view()) {
1313 ++_final_thread_count;
1314 // Handle block of the calling thread is used to create local refs.
1315 fill_frames((jthread)JNIHandles::make_local(_calling_thread, thread_oop),
1316 jt, thread_oop);
1317 }
1318 }
1319 allocate_and_fill_stacks(_final_thread_count);
1320 }
1321
1322 // Verifies that the top frame is a java frame in an expected state.
1323 // Deoptimizes frame if needed.
1324 // Checks that the frame method signature matches the return type (tos).
1325 // HandleMark must be defined in the caller only.
1326 // It is to keep a ret_ob_h handle alive after return to the caller.
1327 jvmtiError
1328 JvmtiEnvBase::check_top_frame(JavaThread* current_thread, JavaThread* java_thread,
1329 jvalue value, TosState tos, Handle* ret_ob_h) {
1330 ResourceMark rm(current_thread);
1331
1332 vframe *vf = vframeFor(java_thread, 0);
1333 NULL_CHECK(vf, JVMTI_ERROR_NO_MORE_FRAMES);
1334
1335 javaVFrame *jvf = (javaVFrame*) vf;
1336 if (!vf->is_java_frame() || jvf->method()->is_native()) {
1337 return JVMTI_ERROR_OPAQUE_FRAME;
1338 }
1339
1340 // If the frame is a compiled one, need to deoptimize it.
1341 if (vf->is_compiled_frame()) {
1342 if (!vf->fr().can_be_deoptimized()) {
1343 return JVMTI_ERROR_OPAQUE_FRAME;
1344 }
1345 VM_DeoptimizeFrame deopt(java_thread, jvf->fr().id());
1346 VMThread::execute(&deopt);
1347 }
1348
1349 // Get information about method return type
1350 symbolHandle signature(current_thread, jvf->method()->signature());
1351
1352 ResultTypeFinder rtf(signature);
1353 TosState fr_tos = as_TosState(rtf.type());
1354 if (fr_tos != tos) {
1355 if (tos != itos || (fr_tos != btos && fr_tos != ctos && fr_tos != stos)) {
1356 return JVMTI_ERROR_TYPE_MISMATCH;
1357 }
1358 }
1359
1360 // Check that the jobject class matches the return type signature.
1361 jobject jobj = value.l;
1362 if (tos == atos && jobj != NULL) { // NULL reference is allowed
1363 Handle ob_h = Handle(current_thread, JNIHandles::resolve_external_guard(jobj));
1364 NULL_CHECK(ob_h, JVMTI_ERROR_INVALID_OBJECT);
1365 KlassHandle ob_kh = KlassHandle(current_thread, ob_h()->klass());
1366 NULL_CHECK(ob_kh, JVMTI_ERROR_INVALID_OBJECT);
1367
1368 // Method return type signature.
1369 char* ty_sign = 1 + strchr(signature->as_C_string(), ')');
1370
1371 if (!VM_GetOrSetLocal::is_assignable(ty_sign, Klass::cast(ob_kh()), current_thread)) {
1372 return JVMTI_ERROR_TYPE_MISMATCH;
1373 }
1374 *ret_ob_h = ob_h;
1375 }
1376 return JVMTI_ERROR_NONE;
1377 } /* end check_top_frame */
1378
1379
1380 // ForceEarlyReturn<type> follows the PopFrame approach in many aspects.
1381 // Main difference is on the last stage in the interpreter.
1382 // The PopFrame stops method execution to continue execution
1383 // from the same method call instruction.
1384 // The ForceEarlyReturn forces return from method so the execution
1385 // continues at the bytecode following the method call.
1386
1387 // Threads_lock NOT held, java_thread not protected by lock
1388 // java_thread - pre-checked
1389
1390 jvmtiError
1391 JvmtiEnvBase::force_early_return(JavaThread* java_thread, jvalue value, TosState tos) {
1392 JavaThread* current_thread = JavaThread::current();
1393 HandleMark hm(current_thread);
1394 uint32_t debug_bits = 0;
1395
1396 // retrieve or create the state
1397 JvmtiThreadState* state = JvmtiThreadState::state_for(java_thread);
1398 if (state == NULL) {
1399 return JVMTI_ERROR_THREAD_NOT_ALIVE;
1400 }
1401
1402 // Check if java_thread is fully suspended
1403 if (!is_thread_fully_suspended(java_thread,
1404 true /* wait for suspend completion */,
1405 &debug_bits)) {
1406 return JVMTI_ERROR_THREAD_NOT_SUSPENDED;
1407 }
1408
1409 // Check to see if a ForceEarlyReturn was already in progress
1410 if (state->is_earlyret_pending()) {
1411 // Probably possible for JVMTI clients to trigger this, but the
1412 // JPDA backend shouldn't allow this to happen
1413 return JVMTI_ERROR_INTERNAL;
1414 }
1415 {
1416 // The same as for PopFrame. Workaround bug:
1417 // 4812902: popFrame hangs if the method is waiting at a synchronize
1418 // Catch this condition and return an error to avoid hanging.
1419 // Now JVMTI spec allows an implementation to bail out with an opaque
1420 // frame error.
1421 OSThread* osThread = java_thread->osthread();
1422 if (osThread->get_state() == MONITOR_WAIT) {
1423 return JVMTI_ERROR_OPAQUE_FRAME;
1424 }
1425 }
1426 Handle ret_ob_h = Handle();
1427 jvmtiError err = check_top_frame(current_thread, java_thread, value, tos, &ret_ob_h);
1428 if (err != JVMTI_ERROR_NONE) {
1429 return err;
1430 }
1431 assert(tos != atos || value.l == NULL || ret_ob_h() != NULL,
1432 "return object oop must not be NULL if jobject is not NULL");
1433
1434 // Update the thread state to reflect that the top frame must be
1435 // forced to return.
1436 // The current frame will be returned later when the suspended
1437 // thread is resumed and right before returning from VM to Java.
1438 // (see call_VM_base() in assembler_<cpu>.cpp).
1439
1440 state->set_earlyret_pending();
1441 state->set_earlyret_oop(ret_ob_h());
1442 state->set_earlyret_value(value, tos);
1443
1444 // Set pending step flag for this early return.
1445 // It is cleared when next step event is posted.
1446 state->set_pending_step_for_earlyret();
1447
1448 return JVMTI_ERROR_NONE;
1449 } /* end force_early_return */
1450
1451 void
1452 JvmtiMonitorClosure::do_monitor(ObjectMonitor* mon) {
1453 if ( _error != JVMTI_ERROR_NONE) {
1454 // Error occurred in previous iteration so no need to add
1455 // to the list.
1456 return;
1457 }
1458 if (mon->owner() == _java_thread ) {
1459 // Filter out on stack monitors collected during stack walk.
1460 oop obj = (oop)mon->object();
1461 bool found = false;
1462 for (int j = 0; j < _owned_monitors_list->length(); j++) {
1463 jobject jobj = ((jvmtiMonitorStackDepthInfo*)_owned_monitors_list->at(j))->monitor;
1464 oop check = JNIHandles::resolve(jobj);
1465 if (check == obj) {
1466 // On stack monitor already collected during the stack walk.
1467 found = true;
1468 break;
1469 }
1470 }
1471 if (found == false) {
1472 // This is off stack monitor (e.g. acquired via jni MonitorEnter).
1473 jvmtiError err;
1474 jvmtiMonitorStackDepthInfo *jmsdi;
1475 err = _env->allocate(sizeof(jvmtiMonitorStackDepthInfo), (unsigned char **)&jmsdi);
1476 if (err != JVMTI_ERROR_NONE) {
1477 _error = err;
1478 return;
1479 }
1480 Handle hobj(obj);
1481 jmsdi->monitor = _env->jni_reference(_calling_thread, hobj);
1482 // stack depth is unknown for this monitor.
1483 jmsdi->stack_depth = -1;
1484 _owned_monitors_list->append(jmsdi);
1485 }
1486 }
1487 }
1488
1489 #endif // !JVMTI_KERNEL