1 /*
2 * Copyright (c) 2003, 2015, 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 "oops/oop.inline.hpp"
31 #include "prims/jvmtiEnvBase.hpp"
32 #include "prims/jvmtiEventController.inline.hpp"
33 #include "prims/jvmtiExtensions.hpp"
34 #include "prims/jvmtiImpl.hpp"
35 #include "prims/jvmtiManageCapabilities.hpp"
36 #include "prims/jvmtiTagMap.hpp"
37 #include "prims/jvmtiThreadState.inline.hpp"
38 #include "runtime/biasedLocking.hpp"
39 #include "runtime/deoptimization.hpp"
40 #include "runtime/interfaceSupport.hpp"
41 #include "runtime/jfieldIDWorkaround.hpp"
42 #include "runtime/objectMonitor.hpp"
43 #include "runtime/objectMonitor.inline.hpp"
44 #include "runtime/signature.hpp"
45 #include "runtime/thread.inline.hpp"
46 #include "runtime/vframe.hpp"
47 #include "runtime/vframe_hp.hpp"
48 #include "runtime/vmThread.hpp"
49 #include "runtime/vm_operations.hpp"
50
51 ///////////////////////////////////////////////////////////////
52 //
53 // JvmtiEnvBase
54 //
55
56 JvmtiEnvBase* JvmtiEnvBase::_head_environment = NULL;
57
58 bool JvmtiEnvBase::_globally_initialized = false;
59 volatile bool JvmtiEnvBase::_needs_clean_up = false;
60
61 jvmtiPhase JvmtiEnvBase::_phase = JVMTI_PHASE_PRIMORDIAL;
62
63 volatile int JvmtiEnvBase::_dying_thread_env_iteration_count = 0;
64
65 extern jvmtiInterface_1_ jvmti_Interface;
66 extern jvmtiInterface_1_ jvmtiTrace_Interface;
67
68
69 // perform initializations that must occur before any JVMTI environments
70 // are released but which should only be initialized once (no matter
71 // how many environments are created).
72 void
73 JvmtiEnvBase::globally_initialize() {
74 assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(), "sanity check");
75 assert(_globally_initialized == false, "bad call");
76
77 JvmtiManageCapabilities::initialize();
78
79 // register extension functions and events
80 JvmtiExtensions::register_extensions();
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 JvmtiTagMap* tag_map_to_deallocate = _tag_map;
240 set_tag_map(NULL);
241 // A tag map can be big, deallocate it now
242 if (tag_map_to_deallocate != NULL) {
243 delete tag_map_to_deallocate;
244 }
245
246 _needs_clean_up = true;
247 }
248
249
250 JvmtiEnvBase::~JvmtiEnvBase() {
251 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
252
253 // There is a small window of time during which the tag map of a
254 // disposed environment could have been reallocated.
255 // Make sure it is gone.
256 JvmtiTagMap* tag_map_to_deallocate = _tag_map;
257 set_tag_map(NULL);
258 // A tag map can be big, deallocate it now
259 if (tag_map_to_deallocate != NULL) {
260 delete tag_map_to_deallocate;
261 }
262
263 _magic = BAD_MAGIC;
264 }
265
266
267 void
268 JvmtiEnvBase::periodic_clean_up() {
269 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
270
271 // JvmtiEnvBase reference is saved in JvmtiEnvThreadState. So
272 // clean up JvmtiThreadState before deleting JvmtiEnv pointer.
273 JvmtiThreadState::periodic_clean_up();
274
275 // Unlink all invalid environments from the list of environments
276 // and deallocate them
277 JvmtiEnvIterator it;
278 JvmtiEnvBase* previous_env = NULL;
279 JvmtiEnvBase* env = it.first();
280 while (env != NULL) {
281 if (env->is_valid()) {
282 previous_env = env;
283 env = it.next(env);
284 } else {
285 // This one isn't valid, remove it from the list and deallocate it
286 JvmtiEnvBase* defunct_env = env;
287 env = it.next(env);
288 if (previous_env == NULL) {
289 _head_environment = env;
290 } else {
291 previous_env->set_next_environment(env);
292 }
293 delete defunct_env;
294 }
295 }
296
297 }
298
299
300 void
301 JvmtiEnvBase::check_for_periodic_clean_up() {
302 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
303
304 class ThreadInsideIterationClosure: public ThreadClosure {
305 private:
306 bool _inside;
307 public:
308 ThreadInsideIterationClosure() : _inside(false) {};
309
310 void do_thread(Thread* thread) {
311 _inside |= thread->is_inside_jvmti_env_iteration();
312 }
313
314 bool is_inside_jvmti_env_iteration() {
315 return _inside;
316 }
317 };
318
319 if (_needs_clean_up) {
320 // Check if we are currently iterating environment,
321 // deallocation should not occur if we are
322 ThreadInsideIterationClosure tiic;
323 Threads::threads_do(&tiic);
324 if (!tiic.is_inside_jvmti_env_iteration() &&
325 !is_inside_dying_thread_env_iteration()) {
326 _needs_clean_up = false;
327 JvmtiEnvBase::periodic_clean_up();
328 }
329 }
330 }
331
332
333 void
334 JvmtiEnvBase::record_first_time_class_file_load_hook_enabled() {
335 assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(),
336 "sanity check");
337
338 if (!_class_file_load_hook_ever_enabled) {
339 _class_file_load_hook_ever_enabled = true;
340
341 if (get_capabilities()->can_retransform_classes) {
342 _is_retransformable = true;
343 } else {
344 _is_retransformable = false;
345
346 // cannot add retransform capability after ClassFileLoadHook has been enabled
347 get_prohibited_capabilities()->can_retransform_classes = 1;
348 }
349 }
350 }
351
352
353 void
354 JvmtiEnvBase::record_class_file_load_hook_enabled() {
355 if (!_class_file_load_hook_ever_enabled) {
356 if (Threads::number_of_threads() == 0) {
357 record_first_time_class_file_load_hook_enabled();
358 } else {
359 MutexLocker mu(JvmtiThreadState_lock);
360 record_first_time_class_file_load_hook_enabled();
361 }
362 }
363 }
364
365
366 jvmtiError
367 JvmtiEnvBase::set_native_method_prefixes(jint prefix_count, char** prefixes) {
368 assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(),
369 "sanity check");
370
371 int old_prefix_count = get_native_method_prefix_count();
372 char **old_prefixes = get_native_method_prefixes();
373
374 // allocate and install the new prefixex
375 if (prefix_count == 0 || !is_valid()) {
376 _native_method_prefix_count = 0;
377 _native_method_prefixes = NULL;
378 } else {
379 // there are prefixes, allocate an array to hold them, and fill it
380 char** new_prefixes = (char**)os::malloc((prefix_count) * sizeof(char*), mtInternal);
381 if (new_prefixes == NULL) {
382 return JVMTI_ERROR_OUT_OF_MEMORY;
383 }
384 for (int i = 0; i < prefix_count; i++) {
385 char* prefix = prefixes[i];
386 if (prefix == NULL) {
387 for (int j = 0; j < (i-1); j++) {
388 os::free(new_prefixes[j]);
389 }
390 os::free(new_prefixes);
391 return JVMTI_ERROR_NULL_POINTER;
392 }
393 prefix = os::strdup(prefixes[i]);
394 if (prefix == NULL) {
395 for (int j = 0; j < (i-1); j++) {
396 os::free(new_prefixes[j]);
397 }
398 os::free(new_prefixes);
399 return JVMTI_ERROR_OUT_OF_MEMORY;
400 }
401 new_prefixes[i] = prefix;
402 }
403 _native_method_prefix_count = prefix_count;
404 _native_method_prefixes = new_prefixes;
405 }
406
407 // now that we know the new prefixes have been successfully installed we can
408 // safely remove the old ones
409 if (old_prefix_count != 0) {
410 for (int i = 0; i < old_prefix_count; i++) {
411 os::free(old_prefixes[i]);
412 }
413 os::free(old_prefixes);
414 }
415
416 return JVMTI_ERROR_NONE;
417 }
418
419
420 // Collect all the prefixes which have been set in any JVM TI environments
421 // by the SetNativeMethodPrefix(es) functions. Be sure to maintain the
422 // order of environments and the order of prefixes within each environment.
423 // Return in a resource allocated array.
424 char**
425 JvmtiEnvBase::get_all_native_method_prefixes(int* count_ptr) {
426 assert(Threads::number_of_threads() == 0 ||
427 SafepointSynchronize::is_at_safepoint() ||
428 JvmtiThreadState_lock->is_locked(),
429 "sanity check");
430
431 int total_count = 0;
432 GrowableArray<char*>* prefix_array =new GrowableArray<char*>(5);
433
434 JvmtiEnvIterator it;
435 for (JvmtiEnvBase* env = it.first(); env != NULL; env = it.next(env)) {
436 int prefix_count = env->get_native_method_prefix_count();
437 char** prefixes = env->get_native_method_prefixes();
438 for (int j = 0; j < prefix_count; j++) {
439 // retrieve a prefix and so that it is safe against asynchronous changes
440 // copy it into the resource area
441 char* prefix = prefixes[j];
442 char* prefix_copy = NEW_RESOURCE_ARRAY(char, strlen(prefix)+1);
443 strcpy(prefix_copy, prefix);
444 prefix_array->at_put_grow(total_count++, prefix_copy);
445 }
446 }
447
448 char** all_prefixes = NEW_RESOURCE_ARRAY(char*, total_count);
449 char** p = all_prefixes;
450 for (int i = 0; i < total_count; ++i) {
451 *p++ = prefix_array->at(i);
452 }
453 *count_ptr = total_count;
454 return all_prefixes;
455 }
456
457 void
458 JvmtiEnvBase::set_event_callbacks(const jvmtiEventCallbacks* callbacks,
459 jint size_of_callbacks) {
460 assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(), "sanity check");
461
462 size_t byte_cnt = sizeof(jvmtiEventCallbacks);
463
464 // clear in either case to be sure we got any gap between sizes
465 memset(&_event_callbacks, 0, byte_cnt);
466
467 // Now that JvmtiThreadState_lock is held, prevent a possible race condition where events
468 // are re-enabled by a call to set event callbacks where the DisposeEnvironment
469 // occurs after the boiler-plate environment check and before the lock is acquired.
470 if (callbacks != NULL && is_valid()) {
471 if (size_of_callbacks < (jint)byte_cnt) {
472 byte_cnt = size_of_callbacks;
473 }
474 memcpy(&_event_callbacks, callbacks, byte_cnt);
475 }
476 }
477
478 // Called from JVMTI entry points which perform stack walking. If the
479 // associated JavaThread is the current thread, then wait_for_suspend
480 // is not used. Otherwise, it determines if we should wait for the
481 // "other" thread to complete external suspension. (NOTE: in future
482 // releases the suspension mechanism should be reimplemented so this
483 // is not necessary.)
484 //
485 bool
486 JvmtiEnvBase::is_thread_fully_suspended(JavaThread* thr, bool wait_for_suspend, uint32_t *bits) {
487 // "other" threads require special handling
488 if (thr != JavaThread::current()) {
489 if (wait_for_suspend) {
490 // We are allowed to wait for the external suspend to complete
491 // so give the other thread a chance to get suspended.
492 if (!thr->wait_for_ext_suspend_completion(SuspendRetryCount,
493 SuspendRetryDelay, bits)) {
494 // didn't make it so let the caller know
495 return false;
496 }
497 }
498 // We aren't allowed to wait for the external suspend to complete
499 // so if the other thread isn't externally suspended we need to
500 // let the caller know.
501 else if (!thr->is_ext_suspend_completed_with_lock(bits)) {
502 return false;
503 }
504 }
505
506 return true;
507 }
508
509
510 // In the fullness of time, all users of the method should instead
511 // directly use allocate, besides being cleaner and faster, this will
512 // mean much better out of memory handling
513 unsigned char *
514 JvmtiEnvBase::jvmtiMalloc(jlong size) {
515 unsigned char* mem;
516 jvmtiError result = allocate(size, &mem);
517 assert(result == JVMTI_ERROR_NONE, "Allocate failed");
518 return mem;
519 }
520
521
522 //
523 // Threads
524 //
525
526 jobject *
527 JvmtiEnvBase::new_jobjectArray(int length, Handle *handles) {
528 if (length == 0) {
529 return NULL;
530 }
531
532 jobject *objArray = (jobject *) jvmtiMalloc(sizeof(jobject) * length);
533 NULL_CHECK(objArray, NULL);
534
535 for (int i=0; i<length; i++) {
536 objArray[i] = jni_reference(handles[i]);
537 }
538 return objArray;
539 }
540
541 jthread *
542 JvmtiEnvBase::new_jthreadArray(int length, Handle *handles) {
543 return (jthread *) new_jobjectArray(length,handles);
544 }
545
546 jthreadGroup *
547 JvmtiEnvBase::new_jthreadGroupArray(int length, Handle *handles) {
548 return (jthreadGroup *) new_jobjectArray(length,handles);
549 }
550
551
552 JavaThread *
553 JvmtiEnvBase::get_JavaThread(jthread jni_thread) {
554 oop t = JNIHandles::resolve_external_guard(jni_thread);
555 if (t == NULL || !t->is_a(SystemDictionary::Thread_klass())) {
556 return NULL;
557 }
558 // The following returns NULL if the thread has not yet run or is in
559 // process of exiting
560 return java_lang_Thread::thread(t);
561 }
562
563
564 // return the vframe on the specified thread and depth, NULL if no such frame
565 vframe*
566 JvmtiEnvBase::vframeFor(JavaThread* java_thread, jint depth) {
567 if (!java_thread->has_last_Java_frame()) {
568 return NULL;
569 }
570 RegisterMap reg_map(java_thread);
571 vframe *vf = java_thread->last_java_vframe(®_map);
572 int d = 0;
573 while ((vf != NULL) && (d < depth)) {
574 vf = vf->java_sender();
575 d++;
576 }
577 return vf;
578 }
579
580
581 //
582 // utilities: JNI objects
583 //
584
585
586 jclass
587 JvmtiEnvBase::get_jni_class_non_null(Klass* k) {
588 assert(k != NULL, "k != NULL");
589 return (jclass)jni_reference(k->java_mirror());
590 }
591
592 //
593 // Field Information
594 //
595
596 bool
597 JvmtiEnvBase::get_field_descriptor(Klass* k, jfieldID field, fieldDescriptor* fd) {
598 if (!jfieldIDWorkaround::is_valid_jfieldID(k, field)) {
599 return false;
600 }
601 bool found = false;
602 if (jfieldIDWorkaround::is_static_jfieldID(field)) {
603 JNIid* id = jfieldIDWorkaround::from_static_jfieldID(field);
604 found = id->find_local_field(fd);
605 } else {
606 // Non-static field. The fieldID is really the offset of the field within the object.
607 int offset = jfieldIDWorkaround::from_instance_jfieldID(k, field);
608 found = InstanceKlass::cast(k)->find_field_from_offset(offset, false, fd);
609 }
610 return found;
611 }
612
613 //
614 // Object Monitor Information
615 //
616
617 //
618 // Count the number of objects for a lightweight monitor. The hobj
619 // parameter is object that owns the monitor so this routine will
620 // count the number of times the same object was locked by frames
621 // in java_thread.
622 //
623 jint
624 JvmtiEnvBase::count_locked_objects(JavaThread *java_thread, Handle hobj) {
625 jint ret = 0;
626 if (!java_thread->has_last_Java_frame()) {
627 return ret; // no Java frames so no monitors
628 }
629
630 ResourceMark rm;
631 HandleMark hm;
632 RegisterMap reg_map(java_thread);
633
634 for(javaVFrame *jvf=java_thread->last_java_vframe(®_map); jvf != NULL;
635 jvf = jvf->java_sender()) {
636 GrowableArray<MonitorInfo*>* mons = jvf->monitors();
637 if (!mons->is_empty()) {
638 for (int i = 0; i < mons->length(); i++) {
639 MonitorInfo *mi = mons->at(i);
640 if (mi->owner_is_scalar_replaced()) continue;
641
642 // see if owner of the monitor is our object
643 if (mi->owner() != NULL && mi->owner() == hobj()) {
644 ret++;
645 }
646 }
647 }
648 }
649 return ret;
650 }
651
652
653
654 jvmtiError
655 JvmtiEnvBase::get_current_contended_monitor(JavaThread *calling_thread, JavaThread *java_thread, jobject *monitor_ptr) {
656 #ifdef ASSERT
657 uint32_t debug_bits = 0;
658 #endif
659 assert((SafepointSynchronize::is_at_safepoint() ||
660 is_thread_fully_suspended(java_thread, false, &debug_bits)),
661 "at safepoint or target thread is suspended");
662 oop obj = NULL;
663 ObjectMonitor *mon = java_thread->current_waiting_monitor();
664 if (mon == NULL) {
665 // thread is not doing an Object.wait() call
666 mon = java_thread->current_pending_monitor();
667 if (mon != NULL) {
668 // The thread is trying to enter() or raw_enter() an ObjectMonitor.
669 obj = (oop)mon->object();
670 // If obj == NULL, then ObjectMonitor is raw which doesn't count
671 // as contended for this API
672 }
673 // implied else: no contended ObjectMonitor
674 } else {
675 // thread is doing an Object.wait() call
676 obj = (oop)mon->object();
677 assert(obj != NULL, "Object.wait() should have an object");
678 }
679
680 if (obj == NULL) {
681 *monitor_ptr = NULL;
682 } else {
683 HandleMark hm;
684 Handle hobj(obj);
685 *monitor_ptr = jni_reference(calling_thread, hobj);
686 }
687 return JVMTI_ERROR_NONE;
688 }
689
690
691 jvmtiError
692 JvmtiEnvBase::get_owned_monitors(JavaThread *calling_thread, JavaThread* java_thread,
693 GrowableArray<jvmtiMonitorStackDepthInfo*> *owned_monitors_list) {
694 jvmtiError err = JVMTI_ERROR_NONE;
695 #ifdef ASSERT
696 uint32_t debug_bits = 0;
697 #endif
698 assert((SafepointSynchronize::is_at_safepoint() ||
699 is_thread_fully_suspended(java_thread, false, &debug_bits)),
700 "at safepoint or target thread is suspended");
701
702 if (java_thread->has_last_Java_frame()) {
703 ResourceMark rm;
704 HandleMark hm;
705 RegisterMap reg_map(java_thread);
706
707 int depth = 0;
708 for (javaVFrame *jvf = java_thread->last_java_vframe(®_map); jvf != NULL;
709 jvf = jvf->java_sender()) {
710 if (depth++ < MaxJavaStackTraceDepth) { // check for stack too deep
711 // add locked objects for this frame into list
712 err = get_locked_objects_in_frame(calling_thread, java_thread, jvf, owned_monitors_list, depth-1);
713 if (err != JVMTI_ERROR_NONE) {
714 return err;
715 }
716 }
717 }
718 }
719
720 // Get off stack monitors. (e.g. acquired via jni MonitorEnter).
721 JvmtiMonitorClosure jmc(java_thread, calling_thread, owned_monitors_list, this);
722 ObjectSynchronizer::monitors_iterate(&jmc);
723 err = jmc.error();
724
725 return err;
726 }
727
728 // Save JNI local handles for any objects that this frame owns.
729 jvmtiError
730 JvmtiEnvBase::get_locked_objects_in_frame(JavaThread* calling_thread, JavaThread* java_thread,
731 javaVFrame *jvf, GrowableArray<jvmtiMonitorStackDepthInfo*>* owned_monitors_list, int stack_depth) {
732 jvmtiError err = JVMTI_ERROR_NONE;
733 ResourceMark rm;
734
735 GrowableArray<MonitorInfo*>* mons = jvf->monitors();
736 if (mons->is_empty()) {
737 return err; // this javaVFrame holds no monitors
738 }
739
740 HandleMark hm;
741 oop wait_obj = NULL;
742 {
743 // save object of current wait() call (if any) for later comparison
744 ObjectMonitor *mon = java_thread->current_waiting_monitor();
745 if (mon != NULL) {
746 wait_obj = (oop)mon->object();
747 }
748 }
749 oop pending_obj = NULL;
750 {
751 // save object of current enter() call (if any) for later comparison
752 ObjectMonitor *mon = java_thread->current_pending_monitor();
753 if (mon != NULL) {
754 pending_obj = (oop)mon->object();
755 }
756 }
757
758 for (int i = 0; i < mons->length(); i++) {
759 MonitorInfo *mi = mons->at(i);
760
761 if (mi->owner_is_scalar_replaced()) continue;
762
763 oop obj = mi->owner();
764 if (obj == NULL) {
765 // this monitor doesn't have an owning object so skip it
766 continue;
767 }
768
769 if (wait_obj == obj) {
770 // the thread is waiting on this monitor so it isn't really owned
771 continue;
772 }
773
774 if (pending_obj == obj) {
775 // the thread is pending on this monitor so it isn't really owned
776 continue;
777 }
778
779 if (owned_monitors_list->length() > 0) {
780 // Our list has at least one object on it so we have to check
781 // for recursive object locking
782 bool found = false;
783 for (int j = 0; j < owned_monitors_list->length(); j++) {
784 jobject jobj = ((jvmtiMonitorStackDepthInfo*)owned_monitors_list->at(j))->monitor;
785 oop check = JNIHandles::resolve(jobj);
786 if (check == obj) {
787 found = true; // we found the object
788 break;
789 }
790 }
791
792 if (found) {
793 // already have this object so don't include it
794 continue;
795 }
796 }
797
798 // add the owning object to our list
799 jvmtiMonitorStackDepthInfo *jmsdi;
800 err = allocate(sizeof(jvmtiMonitorStackDepthInfo), (unsigned char **)&jmsdi);
801 if (err != JVMTI_ERROR_NONE) {
802 return err;
803 }
804 Handle hobj(obj);
805 jmsdi->monitor = jni_reference(calling_thread, hobj);
806 jmsdi->stack_depth = stack_depth;
807 owned_monitors_list->append(jmsdi);
808 }
809
810 return err;
811 }
812
813 jvmtiError
814 JvmtiEnvBase::get_stack_trace(JavaThread *java_thread,
815 jint start_depth, jint max_count,
816 jvmtiFrameInfo* frame_buffer, jint* count_ptr) {
817 #ifdef ASSERT
818 uint32_t debug_bits = 0;
819 #endif
820 assert((SafepointSynchronize::is_at_safepoint() ||
821 is_thread_fully_suspended(java_thread, false, &debug_bits)),
822 "at safepoint or target thread is suspended");
823 int count = 0;
824 if (java_thread->has_last_Java_frame()) {
825 RegisterMap reg_map(java_thread);
826 Thread* current_thread = Thread::current();
827 ResourceMark rm(current_thread);
828 javaVFrame *jvf = java_thread->last_java_vframe(®_map);
829 HandleMark hm(current_thread);
830 if (start_depth != 0) {
831 if (start_depth > 0) {
832 for (int j = 0; j < start_depth && jvf != NULL; j++) {
833 jvf = jvf->java_sender();
834 }
835 if (jvf == NULL) {
836 // start_depth is deeper than the stack depth
837 return JVMTI_ERROR_ILLEGAL_ARGUMENT;
838 }
839 } else { // start_depth < 0
840 // we are referencing the starting depth based on the oldest
841 // part of the stack.
842 // optimize to limit the number of times that java_sender() is called
843 javaVFrame *jvf_cursor = jvf;
844 javaVFrame *jvf_prev = NULL;
845 javaVFrame *jvf_prev_prev = NULL;
846 int j = 0;
847 while (jvf_cursor != NULL) {
848 jvf_prev_prev = jvf_prev;
849 jvf_prev = jvf_cursor;
850 for (j = 0; j > start_depth && jvf_cursor != NULL; j--) {
851 jvf_cursor = jvf_cursor->java_sender();
852 }
853 }
854 if (j == start_depth) {
855 // previous pointer is exactly where we want to start
856 jvf = jvf_prev;
857 } else {
858 // we need to back up further to get to the right place
859 if (jvf_prev_prev == NULL) {
860 // the -start_depth is greater than the stack depth
861 return JVMTI_ERROR_ILLEGAL_ARGUMENT;
862 }
863 // j now is the number of frames on the stack starting with
864 // jvf_prev, we start from jvf_prev_prev and move older on
865 // the stack that many, the result is -start_depth frames
866 // remaining.
867 jvf = jvf_prev_prev;
868 for (; j < 0; j++) {
869 jvf = jvf->java_sender();
870 }
871 }
872 }
873 }
874 for (; count < max_count && jvf != NULL; count++) {
875 frame_buffer[count].method = jvf->method()->jmethod_id();
876 frame_buffer[count].location = (jvf->method()->is_native() ? -1 : jvf->bci());
877 jvf = jvf->java_sender();
878 }
879 } else {
880 if (start_depth != 0) {
881 // no frames and there is a starting depth
882 return JVMTI_ERROR_ILLEGAL_ARGUMENT;
883 }
884 }
885 *count_ptr = count;
886 return JVMTI_ERROR_NONE;
887 }
888
889 jvmtiError
890 JvmtiEnvBase::get_frame_count(JvmtiThreadState *state, jint *count_ptr) {
891 assert((state != NULL),
892 "JavaThread should create JvmtiThreadState before calling this method");
893 *count_ptr = state->count_frames();
894 return JVMTI_ERROR_NONE;
895 }
896
897 jvmtiError
898 JvmtiEnvBase::get_frame_location(JavaThread *java_thread, jint depth,
899 jmethodID* method_ptr, jlocation* location_ptr) {
900 #ifdef ASSERT
901 uint32_t debug_bits = 0;
902 #endif
903 assert((SafepointSynchronize::is_at_safepoint() ||
904 is_thread_fully_suspended(java_thread, false, &debug_bits)),
905 "at safepoint or target thread is suspended");
906 Thread* current_thread = Thread::current();
907 ResourceMark rm(current_thread);
908
909 vframe *vf = vframeFor(java_thread, depth);
910 if (vf == NULL) {
911 return JVMTI_ERROR_NO_MORE_FRAMES;
912 }
913
914 // vframeFor should return a java frame. If it doesn't
915 // it means we've got an internal error and we return the
916 // error in product mode. In debug mode we will instead
917 // attempt to cast the vframe to a javaVFrame and will
918 // cause an assertion/crash to allow further diagnosis.
919 #ifdef PRODUCT
920 if (!vf->is_java_frame()) {
921 return JVMTI_ERROR_INTERNAL;
922 }
923 #endif
924
925 HandleMark hm(current_thread);
926 javaVFrame *jvf = javaVFrame::cast(vf);
927 Method* method = jvf->method();
928 if (method->is_native()) {
929 *location_ptr = -1;
930 } else {
931 *location_ptr = jvf->bci();
932 }
933 *method_ptr = method->jmethod_id();
934
935 return JVMTI_ERROR_NONE;
936 }
937
938
939 jvmtiError
940 JvmtiEnvBase::get_object_monitor_usage(JavaThread* calling_thread, jobject object, jvmtiMonitorUsage* info_ptr) {
941 HandleMark hm;
942 Handle hobj;
943
944 bool at_safepoint = SafepointSynchronize::is_at_safepoint();
945
946 // Check arguments
947 {
948 oop mirror = JNIHandles::resolve_external_guard(object);
949 NULL_CHECK(mirror, JVMTI_ERROR_INVALID_OBJECT);
950 NULL_CHECK(info_ptr, JVMTI_ERROR_NULL_POINTER);
951
952 hobj = Handle(mirror);
953 }
954
955 JavaThread *owning_thread = NULL;
956 ObjectMonitor *mon = NULL;
957 jvmtiMonitorUsage ret = {
958 NULL, 0, 0, NULL, 0, NULL
959 };
960
961 uint32_t debug_bits = 0;
962 // first derive the object's owner and entry_count (if any)
963 {
964 // Revoke any biases before querying the mark word
965 if (SafepointSynchronize::is_at_safepoint()) {
966 BiasedLocking::revoke_at_safepoint(hobj);
967 } else {
968 BiasedLocking::revoke_and_rebias(hobj, false, calling_thread);
969 }
970
971 address owner = NULL;
972 {
973 markOop mark = hobj()->mark();
974
975 if (!mark->has_monitor()) {
976 // this object has a lightweight monitor
977
978 if (mark->has_locker()) {
979 owner = (address)mark->locker(); // save the address of the Lock word
980 }
981 // implied else: no owner
982 } else {
983 // this object has a heavyweight monitor
984 mon = mark->monitor();
985
986 // The owner field of a heavyweight monitor may be NULL for no
987 // owner, a JavaThread * or it may still be the address of the
988 // Lock word in a JavaThread's stack. A monitor can be inflated
989 // by a non-owning JavaThread, but only the owning JavaThread
990 // can change the owner field from the Lock word to the
991 // JavaThread * and it may not have done that yet.
992 owner = (address)mon->owner();
993 }
994 }
995
996 if (owner != NULL) {
997 // This monitor is owned so we have to find the owning JavaThread.
998 // Since owning_thread_from_monitor_owner() grabs a lock, GC can
999 // move our object at this point. However, our owner value is safe
1000 // since it is either the Lock word on a stack or a JavaThread *.
1001 owning_thread = Threads::owning_thread_from_monitor_owner(owner, !at_safepoint);
1002 // Cannot assume (owning_thread != NULL) here because this function
1003 // may not have been called at a safepoint and the owning_thread
1004 // might not be suspended.
1005 if (owning_thread != NULL) {
1006 // The monitor's owner either has to be the current thread, at safepoint
1007 // or it has to be suspended. Any of these conditions will prevent both
1008 // contending and waiting threads from modifying the state of
1009 // the monitor.
1010 if (!at_safepoint && !JvmtiEnv::is_thread_fully_suspended(owning_thread, true, &debug_bits)) {
1011 // Don't worry! This return of JVMTI_ERROR_THREAD_NOT_SUSPENDED
1012 // will not make it back to the JVM/TI agent. The error code will
1013 // get intercepted in JvmtiEnv::GetObjectMonitorUsage() which
1014 // will retry the call via a VM_GetObjectMonitorUsage VM op.
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 // The recursions field of a monitor does not reflect recursions
1026 // as lightweight locks before inflating the monitor are not included.
1027 // We have to count the number of recursive monitor entries the hard way.
1028 // We pass a handle to survive any GCs along the way.
1029 ResourceMark rm;
1030 ret.entry_count = count_locked_objects(owning_thread, hobj);
1031 }
1032 // implied else: entry_count == 0
1033 }
1034
1035 jint nWant, nWait;
1036 if (mon != NULL) {
1037 // this object has a heavyweight monitor
1038 nWant = mon->contentions(); // # of threads contending for monitor
1039 nWait = mon->waiters(); // # of threads in Object.wait()
1040 ret.waiter_count = nWant + nWait;
1041 ret.notify_waiter_count = nWait;
1042 } else {
1043 // this object has a lightweight monitor
1044 ret.waiter_count = 0;
1045 ret.notify_waiter_count = 0;
1046 }
1047
1048 // Allocate memory for heavyweight and lightweight monitor.
1049 jvmtiError err;
1050 err = allocate(ret.waiter_count * sizeof(jthread *), (unsigned char**)&ret.waiters);
1051 if (err != JVMTI_ERROR_NONE) {
1052 return err;
1053 }
1054 err = allocate(ret.notify_waiter_count * sizeof(jthread *),
1055 (unsigned char**)&ret.notify_waiters);
1056 if (err != JVMTI_ERROR_NONE) {
1057 deallocate((unsigned char*)ret.waiters);
1058 return err;
1059 }
1060
1061 // now derive the rest of the fields
1062 if (mon != NULL) {
1063 // this object has a heavyweight monitor
1064
1065 // Number of waiters may actually be less than the waiter count.
1066 // So NULL out memory so that unused memory will be NULL.
1067 memset(ret.waiters, 0, ret.waiter_count * sizeof(jthread *));
1068 memset(ret.notify_waiters, 0, ret.notify_waiter_count * sizeof(jthread *));
1069
1070 if (ret.waiter_count > 0) {
1071 // we have contending and/or waiting threads
1072 HandleMark hm;
1073 if (nWant > 0) {
1074 // we have contending threads
1075 ResourceMark rm;
1076 // get_pending_threads returns only java thread so we do not need to
1077 // check for non java threads.
1078 GrowableArray<JavaThread*>* wantList = Threads::get_pending_threads(
1079 nWant, (address)mon, !at_safepoint);
1080 if (wantList->length() < nWant) {
1081 // robustness: the pending list has gotten smaller
1082 nWant = wantList->length();
1083 }
1084 for (int i = 0; i < nWant; i++) {
1085 JavaThread *pending_thread = wantList->at(i);
1086 // If the monitor has no owner, then a non-suspended contending
1087 // thread could potentially change the state of the monitor by
1088 // entering it. The JVM/TI spec doesn't allow this.
1089 if (owning_thread == NULL && !at_safepoint &
1090 !JvmtiEnv::is_thread_fully_suspended(pending_thread, true, &debug_bits)) {
1091 if (ret.owner != NULL) {
1092 destroy_jni_reference(calling_thread, ret.owner);
1093 }
1094 for (int j = 0; j < i; j++) {
1095 destroy_jni_reference(calling_thread, ret.waiters[j]);
1096 }
1097 deallocate((unsigned char*)ret.waiters);
1098 deallocate((unsigned char*)ret.notify_waiters);
1099 return JVMTI_ERROR_THREAD_NOT_SUSPENDED;
1100 }
1101 Handle th(pending_thread->threadObj());
1102 ret.waiters[i] = (jthread)jni_reference(calling_thread, th);
1103 }
1104 }
1105 if (nWait > 0) {
1106 // we have threads in Object.wait()
1107 int offset = nWant; // add after any contending threads
1108 ObjectWaiter *waiter = mon->first_waiter();
1109 for (int i = 0, j = 0; i < nWait; i++) {
1110 if (waiter == NULL) {
1111 // robustness: the waiting list has gotten smaller
1112 nWait = j;
1113 break;
1114 }
1115 Thread *t = mon->thread_of_waiter(waiter);
1116 if (t != NULL && t->is_Java_thread()) {
1117 JavaThread *wjava_thread = (JavaThread *)t;
1118 // If the thread was found on the ObjectWaiter list, then
1119 // it has not been notified. This thread can't change the
1120 // state of the monitor so it doesn't need to be suspended.
1121 Handle th(wjava_thread->threadObj());
1122 ret.waiters[offset + j] = (jthread)jni_reference(calling_thread, th);
1123 ret.notify_waiters[j++] = (jthread)jni_reference(calling_thread, th);
1124 }
1125 waiter = mon->next_waiter(waiter);
1126 }
1127 }
1128 }
1129
1130 // Adjust count. nWant and nWait count values may be less than original.
1131 ret.waiter_count = nWant + nWait;
1132 ret.notify_waiter_count = nWait;
1133 } else {
1134 // this object has a lightweight monitor and we have nothing more
1135 // to do here because the defaults are just fine.
1136 }
1137
1138 // we don't update return parameter unless everything worked
1139 *info_ptr = ret;
1140
1141 return JVMTI_ERROR_NONE;
1142 }
1143
1144 ResourceTracker::ResourceTracker(JvmtiEnv* env) {
1145 _env = env;
1146 _allocations = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<unsigned char*>(20, true);
1147 _failed = false;
1148 }
1149 ResourceTracker::~ResourceTracker() {
1150 if (_failed) {
1151 for (int i=0; i<_allocations->length(); i++) {
1152 _env->deallocate(_allocations->at(i));
1153 }
1154 }
1155 delete _allocations;
1156 }
1157
1158 jvmtiError ResourceTracker::allocate(jlong size, unsigned char** mem_ptr) {
1159 unsigned char *ptr;
1160 jvmtiError err = _env->allocate(size, &ptr);
1161 if (err == JVMTI_ERROR_NONE) {
1162 _allocations->append(ptr);
1163 *mem_ptr = ptr;
1164 } else {
1165 *mem_ptr = NULL;
1166 _failed = true;
1167 }
1168 return err;
1169 }
1170
1171 unsigned char* ResourceTracker::allocate(jlong size) {
1172 unsigned char* ptr;
1173 allocate(size, &ptr);
1174 return ptr;
1175 }
1176
1177 char* ResourceTracker::strdup(const char* str) {
1178 char *dup_str = (char*)allocate(strlen(str)+1);
1179 if (dup_str != NULL) {
1180 strcpy(dup_str, str);
1181 }
1182 return dup_str;
1183 }
1184
1185 struct StackInfoNode {
1186 struct StackInfoNode *next;
1187 jvmtiStackInfo info;
1188 };
1189
1190 // Create a jvmtiStackInfo inside a linked list node and create a
1191 // buffer for the frame information, both allocated as resource objects.
1192 // Fill in both the jvmtiStackInfo and the jvmtiFrameInfo.
1193 // Note that either or both of thr and thread_oop
1194 // may be null if the thread is new or has exited.
1195 void
1196 VM_GetMultipleStackTraces::fill_frames(jthread jt, JavaThread *thr, oop thread_oop) {
1197 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
1198
1199 jint state = 0;
1200 struct StackInfoNode *node = NEW_RESOURCE_OBJ(struct StackInfoNode);
1201 jvmtiStackInfo *infop = &(node->info);
1202 node->next = head();
1203 set_head(node);
1204 infop->frame_count = 0;
1205 infop->thread = jt;
1206
1207 if (thread_oop != NULL) {
1208 // get most state bits
1209 state = (jint)java_lang_Thread::get_thread_status(thread_oop);
1210 }
1211
1212 if (thr != NULL) { // add more state bits if there is a JavaThead to query
1213 // same as is_being_ext_suspended() but without locking
1214 if (thr->is_ext_suspended() || thr->is_external_suspend()) {
1215 state |= JVMTI_THREAD_STATE_SUSPENDED;
1216 }
1217 JavaThreadState jts = thr->thread_state();
1218 if (jts == _thread_in_native) {
1219 state |= JVMTI_THREAD_STATE_IN_NATIVE;
1220 }
1221 OSThread* osThread = thr->osthread();
1222 if (osThread != NULL && osThread->interrupted()) {
1223 state |= JVMTI_THREAD_STATE_INTERRUPTED;
1224 }
1225 }
1226 infop->state = state;
1227
1228 if (thr != NULL || (state & JVMTI_THREAD_STATE_ALIVE) != 0) {
1229 infop->frame_buffer = NEW_RESOURCE_ARRAY(jvmtiFrameInfo, max_frame_count());
1230 env()->get_stack_trace(thr, 0, max_frame_count(),
1231 infop->frame_buffer, &(infop->frame_count));
1232 } else {
1233 infop->frame_buffer = NULL;
1234 infop->frame_count = 0;
1235 }
1236 _frame_count_total += infop->frame_count;
1237 }
1238
1239 // Based on the stack information in the linked list, allocate memory
1240 // block to return and fill it from the info in the linked list.
1241 void
1242 VM_GetMultipleStackTraces::allocate_and_fill_stacks(jint thread_count) {
1243 // do I need to worry about alignment issues?
1244 jlong alloc_size = thread_count * sizeof(jvmtiStackInfo)
1245 + _frame_count_total * sizeof(jvmtiFrameInfo);
1246 env()->allocate(alloc_size, (unsigned char **)&_stack_info);
1247
1248 // pointers to move through the newly allocated space as it is filled in
1249 jvmtiStackInfo *si = _stack_info + thread_count; // bottom of stack info
1250 jvmtiFrameInfo *fi = (jvmtiFrameInfo *)si; // is the top of frame info
1251
1252 // copy information in resource area into allocated buffer
1253 // insert stack info backwards since linked list is backwards
1254 // insert frame info forwards
1255 // walk the StackInfoNodes
1256 for (struct StackInfoNode *sin = head(); sin != NULL; sin = sin->next) {
1257 jint frame_count = sin->info.frame_count;
1258 size_t frames_size = frame_count * sizeof(jvmtiFrameInfo);
1259 --si;
1260 memcpy(si, &(sin->info), sizeof(jvmtiStackInfo));
1261 if (frames_size == 0) {
1262 si->frame_buffer = NULL;
1263 } else {
1264 memcpy(fi, sin->info.frame_buffer, frames_size);
1265 si->frame_buffer = fi; // point to the new allocated copy of the frames
1266 fi += frame_count;
1267 }
1268 }
1269 assert(si == _stack_info, "the last copied stack info must be the first record");
1270 assert((unsigned char *)fi == ((unsigned char *)_stack_info) + alloc_size,
1271 "the last copied frame info must be the last record");
1272 }
1273
1274
1275 void
1276 VM_GetThreadListStackTraces::doit() {
1277 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
1278
1279 ResourceMark rm;
1280 for (int i = 0; i < _thread_count; ++i) {
1281 jthread jt = _thread_list[i];
1282 oop thread_oop = JNIHandles::resolve_external_guard(jt);
1283 if (thread_oop == NULL || !thread_oop->is_a(SystemDictionary::Thread_klass())) {
1284 set_result(JVMTI_ERROR_INVALID_THREAD);
1285 return;
1286 }
1287 fill_frames(jt, java_lang_Thread::thread(thread_oop), thread_oop);
1288 }
1289 allocate_and_fill_stacks(_thread_count);
1290 }
1291
1292 void
1293 VM_GetAllStackTraces::doit() {
1294 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
1295
1296 ResourceMark rm;
1297 _final_thread_count = 0;
1298 for (JavaThread *jt = Threads::first(); jt != NULL; jt = jt->next()) {
1299 oop thread_oop = jt->threadObj();
1300 if (thread_oop != NULL &&
1301 !jt->is_exiting() &&
1302 java_lang_Thread::is_alive(thread_oop) &&
1303 !jt->is_hidden_from_external_view()) {
1304 ++_final_thread_count;
1305 // Handle block of the calling thread is used to create local refs.
1306 fill_frames((jthread)JNIHandles::make_local(_calling_thread, thread_oop),
1307 jt, thread_oop);
1308 }
1309 }
1310 allocate_and_fill_stacks(_final_thread_count);
1311 }
1312
1313 // Verifies that the top frame is a java frame in an expected state.
1314 // Deoptimizes frame if needed.
1315 // Checks that the frame method signature matches the return type (tos).
1316 // HandleMark must be defined in the caller only.
1317 // It is to keep a ret_ob_h handle alive after return to the caller.
1318 jvmtiError
1319 JvmtiEnvBase::check_top_frame(JavaThread* current_thread, JavaThread* java_thread,
1320 jvalue value, TosState tos, Handle* ret_ob_h) {
1321 ResourceMark rm(current_thread);
1322
1323 vframe *vf = vframeFor(java_thread, 0);
1324 NULL_CHECK(vf, JVMTI_ERROR_NO_MORE_FRAMES);
1325
1326 javaVFrame *jvf = (javaVFrame*) vf;
1327 if (!vf->is_java_frame() || jvf->method()->is_native()) {
1328 return JVMTI_ERROR_OPAQUE_FRAME;
1329 }
1330
1331 // If the frame is a compiled one, need to deoptimize it.
1332 if (vf->is_compiled_frame()) {
1333 if (!vf->fr().can_be_deoptimized()) {
1334 return JVMTI_ERROR_OPAQUE_FRAME;
1335 }
1336 Deoptimization::deoptimize_frame(java_thread, jvf->fr().id());
1337 }
1338
1339 // Get information about method return type
1340 Symbol* signature = jvf->method()->signature();
1341
1342 ResultTypeFinder rtf(signature);
1343 TosState fr_tos = as_TosState(rtf.type());
1344 if (fr_tos != tos) {
1345 if (tos != itos || (fr_tos != btos && fr_tos != ctos && fr_tos != stos)) {
1346 return JVMTI_ERROR_TYPE_MISMATCH;
1347 }
1348 }
1349
1350 // Check that the jobject class matches the return type signature.
1351 jobject jobj = value.l;
1352 if (tos == atos && jobj != NULL) { // NULL reference is allowed
1353 Handle ob_h = Handle(current_thread, JNIHandles::resolve_external_guard(jobj));
1354 NULL_CHECK(ob_h, JVMTI_ERROR_INVALID_OBJECT);
1355 KlassHandle ob_kh = KlassHandle(current_thread, ob_h()->klass());
1356 NULL_CHECK(ob_kh, JVMTI_ERROR_INVALID_OBJECT);
1357
1358 // Method return type signature.
1359 char* ty_sign = 1 + strchr(signature->as_C_string(), ')');
1360
1361 if (!VM_GetOrSetLocal::is_assignable(ty_sign, ob_kh(), current_thread)) {
1362 return JVMTI_ERROR_TYPE_MISMATCH;
1363 }
1364 *ret_ob_h = ob_h;
1365 }
1366 return JVMTI_ERROR_NONE;
1367 } /* end check_top_frame */
1368
1369
1370 // ForceEarlyReturn<type> follows the PopFrame approach in many aspects.
1371 // Main difference is on the last stage in the interpreter.
1372 // The PopFrame stops method execution to continue execution
1373 // from the same method call instruction.
1374 // The ForceEarlyReturn forces return from method so the execution
1375 // continues at the bytecode following the method call.
1376
1377 // Threads_lock NOT held, java_thread not protected by lock
1378 // java_thread - pre-checked
1379
1380 jvmtiError
1381 JvmtiEnvBase::force_early_return(JavaThread* java_thread, jvalue value, TosState tos) {
1382 JavaThread* current_thread = JavaThread::current();
1383 HandleMark hm(current_thread);
1384 uint32_t debug_bits = 0;
1385
1386 // retrieve or create the state
1387 JvmtiThreadState* state = JvmtiThreadState::state_for(java_thread);
1388 if (state == NULL) {
1389 return JVMTI_ERROR_THREAD_NOT_ALIVE;
1390 }
1391
1392 // Check if java_thread is fully suspended
1393 if (!is_thread_fully_suspended(java_thread,
1394 true /* wait for suspend completion */,
1395 &debug_bits)) {
1396 return JVMTI_ERROR_THREAD_NOT_SUSPENDED;
1397 }
1398
1399 // Check to see if a ForceEarlyReturn was already in progress
1400 if (state->is_earlyret_pending()) {
1401 // Probably possible for JVMTI clients to trigger this, but the
1402 // JPDA backend shouldn't allow this to happen
1403 return JVMTI_ERROR_INTERNAL;
1404 }
1405 {
1406 // The same as for PopFrame. Workaround bug:
1407 // 4812902: popFrame hangs if the method is waiting at a synchronize
1408 // Catch this condition and return an error to avoid hanging.
1409 // Now JVMTI spec allows an implementation to bail out with an opaque
1410 // frame error.
1411 OSThread* osThread = java_thread->osthread();
1412 if (osThread->get_state() == MONITOR_WAIT) {
1413 return JVMTI_ERROR_OPAQUE_FRAME;
1414 }
1415 }
1416 Handle ret_ob_h = Handle();
1417 jvmtiError err = check_top_frame(current_thread, java_thread, value, tos, &ret_ob_h);
1418 if (err != JVMTI_ERROR_NONE) {
1419 return err;
1420 }
1421 assert(tos != atos || value.l == NULL || ret_ob_h() != NULL,
1422 "return object oop must not be NULL if jobject is not NULL");
1423
1424 // Update the thread state to reflect that the top frame must be
1425 // forced to return.
1426 // The current frame will be returned later when the suspended
1427 // thread is resumed and right before returning from VM to Java.
1428 // (see call_VM_base() in assembler_<cpu>.cpp).
1429
1430 state->set_earlyret_pending();
1431 state->set_earlyret_oop(ret_ob_h());
1432 state->set_earlyret_value(value, tos);
1433
1434 // Set pending step flag for this early return.
1435 // It is cleared when next step event is posted.
1436 state->set_pending_step_for_earlyret();
1437
1438 return JVMTI_ERROR_NONE;
1439 } /* end force_early_return */
1440
1441 void
1442 JvmtiMonitorClosure::do_monitor(ObjectMonitor* mon) {
1443 if ( _error != JVMTI_ERROR_NONE) {
1444 // Error occurred in previous iteration so no need to add
1445 // to the list.
1446 return;
1447 }
1448 if (mon->owner() == _java_thread ) {
1449 // Filter out on stack monitors collected during stack walk.
1450 oop obj = (oop)mon->object();
1451 bool found = false;
1452 for (int j = 0; j < _owned_monitors_list->length(); j++) {
1453 jobject jobj = ((jvmtiMonitorStackDepthInfo*)_owned_monitors_list->at(j))->monitor;
1454 oop check = JNIHandles::resolve(jobj);
1455 if (check == obj) {
1456 // On stack monitor already collected during the stack walk.
1457 found = true;
1458 break;
1459 }
1460 }
1461 if (found == false) {
1462 // This is off stack monitor (e.g. acquired via jni MonitorEnter).
1463 jvmtiError err;
1464 jvmtiMonitorStackDepthInfo *jmsdi;
1465 err = _env->allocate(sizeof(jvmtiMonitorStackDepthInfo), (unsigned char **)&jmsdi);
1466 if (err != JVMTI_ERROR_NONE) {
1467 _error = err;
1468 return;
1469 }
1470 Handle hobj(obj);
1471 jmsdi->monitor = _env->jni_reference(_calling_thread, hobj);
1472 // stack depth is unknown for this monitor.
1473 jmsdi->stack_depth = -1;
1474 _owned_monitors_list->append(jmsdi);
1475 }
1476 }
1477 }