1 /*
2 * Copyright (c) 2003, 2016, 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 "memory/resourceArea.hpp"
29 #include "oops/objArrayKlass.hpp"
30 #include "oops/objArrayOop.hpp"
31 #include "oops/oop.inline.hpp"
32 #include "prims/jvmtiEnvBase.hpp"
33 #include "prims/jvmtiEventController.inline.hpp"
34 #include "prims/jvmtiExtensions.hpp"
35 #include "prims/jvmtiImpl.hpp"
36 #include "prims/jvmtiManageCapabilities.hpp"
37 #include "prims/jvmtiTagMap.hpp"
38 #include "prims/jvmtiThreadState.inline.hpp"
39 #include "runtime/biasedLocking.hpp"
40 #include "runtime/deoptimization.hpp"
41 #include "runtime/interfaceSupport.hpp"
42 #include "runtime/jfieldIDWorkaround.hpp"
43 #include "runtime/objectMonitor.hpp"
44 #include "runtime/objectMonitor.inline.hpp"
45 #include "runtime/signature.hpp"
46 #include "runtime/thread.inline.hpp"
47 #include "runtime/vframe.hpp"
48 #include "runtime/vframe_hp.hpp"
49 #include "runtime/vmThread.hpp"
50 #include "runtime/vm_operations.hpp"
51
52 ///////////////////////////////////////////////////////////////
53 //
54 // JvmtiEnvBase
55 //
56
57 JvmtiEnvBase* JvmtiEnvBase::_head_environment = NULL;
58
59 bool JvmtiEnvBase::_globally_initialized = false;
60 volatile bool JvmtiEnvBase::_needs_clean_up = false;
61
62 jvmtiPhase JvmtiEnvBase::_phase = JVMTI_PHASE_PRIMORDIAL;
63
64 volatile int JvmtiEnvBase::_dying_thread_env_iteration_count = 0;
65
66 extern jvmtiInterface_1_ jvmti_Interface;
67 extern jvmtiInterface_1_ jvmtiTrace_Interface;
68
69
70 // perform initializations that must occur before any JVMTI environments
71 // are released but which should only be initialized once (no matter
72 // how many environments are created).
73 void
74 JvmtiEnvBase::globally_initialize() {
75 assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(), "sanity check");
76 assert(_globally_initialized == false, "bad call");
77
78 JvmtiManageCapabilities::initialize();
79
80 // register extension functions and events
81 JvmtiExtensions::register_extensions();
82
83 #ifdef JVMTI_TRACE
84 JvmtiTrace::initialize();
85 #endif
86
87 _globally_initialized = true;
88 }
89
90
91 void
92 JvmtiEnvBase::initialize() {
93 assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(), "sanity check");
94
95 // Add this environment to the end of the environment list (order is important)
96 {
97 // This block of code must not contain any safepoints, as list deallocation
98 // (which occurs at a safepoint) cannot occur simultaneously with this list
99 // addition. Note: NoSafepointVerifier cannot, currently, be used before
100 // threads exist.
101 JvmtiEnvIterator it;
102 JvmtiEnvBase *previous_env = NULL;
103 for (JvmtiEnvBase* env = it.first(); env != NULL; env = it.next(env)) {
104 previous_env = env;
105 }
106 if (previous_env == NULL) {
107 _head_environment = this;
108 } else {
109 previous_env->set_next_environment(this);
110 }
111 }
112
113 if (_globally_initialized == false) {
114 globally_initialize();
115 }
116 }
117
118
119 bool
120 JvmtiEnvBase::is_valid() {
121 jint value = 0;
122
123 // This object might not be a JvmtiEnvBase so we can't assume
124 // the _magic field is properly aligned. Get the value in a safe
125 // way and then check against JVMTI_MAGIC.
126
127 switch (sizeof(_magic)) {
128 case 2:
129 value = Bytes::get_native_u2((address)&_magic);
130 break;
131
132 case 4:
133 value = Bytes::get_native_u4((address)&_magic);
134 break;
135
136 case 8:
137 value = Bytes::get_native_u8((address)&_magic);
138 break;
139
140 default:
141 guarantee(false, "_magic field is an unexpected size");
142 }
143
144 return value == JVMTI_MAGIC;
145 }
146
147
148 bool
149 JvmtiEnvBase::use_version_1_0_semantics() {
150 int major, minor, micro;
151
152 JvmtiExport::decode_version_values(_version, &major, &minor, µ);
153 return major == 1 && minor == 0; // micro version doesn't matter here
154 }
155
156
157 bool
158 JvmtiEnvBase::use_version_1_1_semantics() {
159 int major, minor, micro;
160
161 JvmtiExport::decode_version_values(_version, &major, &minor, µ);
162 return major == 1 && minor == 1; // micro version doesn't matter here
163 }
164
165 bool
166 JvmtiEnvBase::use_version_1_2_semantics() {
167 int major, minor, micro;
168
169 JvmtiExport::decode_version_values(_version, &major, &minor, µ);
170 return major == 1 && minor == 2; // micro version doesn't matter here
171 }
172
173
174 JvmtiEnvBase::JvmtiEnvBase(jint version) : _env_event_enable() {
175 _version = version;
176 _env_local_storage = NULL;
177 _tag_map = NULL;
178 _native_method_prefix_count = 0;
179 _native_method_prefixes = NULL;
180 _next = NULL;
181 _class_file_load_hook_ever_enabled = false;
182
183 // Moot since ClassFileLoadHook not yet enabled.
184 // But "true" will give a more predictable ClassFileLoadHook behavior
185 // for environment creation during ClassFileLoadHook.
186 _is_retransformable = true;
187
188 // all callbacks initially NULL
189 memset(&_event_callbacks,0,sizeof(jvmtiEventCallbacks));
190
191 // all capabilities initially off
192 memset(&_current_capabilities, 0, sizeof(_current_capabilities));
193
194 // all prohibited capabilities initially off
195 memset(&_prohibited_capabilities, 0, sizeof(_prohibited_capabilities));
196
197 _magic = JVMTI_MAGIC;
198
199 JvmtiEventController::env_initialize((JvmtiEnv*)this);
200
201 #ifdef JVMTI_TRACE
202 _jvmti_external.functions = TraceJVMTI != NULL ? &jvmtiTrace_Interface : &jvmti_Interface;
203 #else
204 _jvmti_external.functions = &jvmti_Interface;
205 #endif
206 }
207
208
209 void
210 JvmtiEnvBase::dispose() {
211
212 #ifdef JVMTI_TRACE
213 JvmtiTrace::shutdown();
214 #endif
215
216 // Dispose of event info and let the event controller call us back
217 // in a locked state (env_dispose, below)
218 JvmtiEventController::env_dispose(this);
219 }
220
221 void
222 JvmtiEnvBase::env_dispose() {
223 assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(), "sanity check");
224
225 // We have been entered with all events disabled on this environment.
226 // A race to re-enable events (by setting callbacks) is prevented by
227 // checking for a valid environment when setting callbacks (while
228 // holding the JvmtiThreadState_lock).
229
230 // Mark as invalid.
231 _magic = DISPOSED_MAGIC;
232
233 // Relinquish all capabilities.
234 jvmtiCapabilities *caps = get_capabilities();
235 JvmtiManageCapabilities::relinquish_capabilities(caps, caps, caps);
236
237 // Same situation as with events (see above)
238 set_native_method_prefixes(0, NULL);
239
240 JvmtiTagMap* tag_map_to_deallocate = _tag_map;
241 set_tag_map(NULL);
242 // A tag map can be big, deallocate it now
243 if (tag_map_to_deallocate != NULL) {
244 delete tag_map_to_deallocate;
245 }
246
247 _needs_clean_up = true;
248 }
249
250
251 JvmtiEnvBase::~JvmtiEnvBase() {
252 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
253
254 // There is a small window of time during which the tag map of a
255 // disposed environment could have been reallocated.
256 // Make sure it is gone.
257 JvmtiTagMap* tag_map_to_deallocate = _tag_map;
258 set_tag_map(NULL);
259 // A tag map can be big, deallocate it now
260 if (tag_map_to_deallocate != NULL) {
261 delete tag_map_to_deallocate;
262 }
263
264 _magic = BAD_MAGIC;
265 }
266
267
268 void
269 JvmtiEnvBase::periodic_clean_up() {
270 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
271
272 // JvmtiEnvBase reference is saved in JvmtiEnvThreadState. So
273 // clean up JvmtiThreadState before deleting JvmtiEnv pointer.
274 JvmtiThreadState::periodic_clean_up();
275
276 // Unlink all invalid environments from the list of environments
277 // and deallocate them
278 JvmtiEnvIterator it;
279 JvmtiEnvBase* previous_env = NULL;
280 JvmtiEnvBase* env = it.first();
281 while (env != NULL) {
282 if (env->is_valid()) {
283 previous_env = env;
284 env = it.next(env);
285 } else {
286 // This one isn't valid, remove it from the list and deallocate it
287 JvmtiEnvBase* defunct_env = env;
288 env = it.next(env);
289 if (previous_env == NULL) {
290 _head_environment = env;
291 } else {
292 previous_env->set_next_environment(env);
293 }
294 delete defunct_env;
295 }
296 }
297
298 }
299
300
301 void
302 JvmtiEnvBase::check_for_periodic_clean_up() {
303 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
304
305 class ThreadInsideIterationClosure: public ThreadClosure {
306 private:
307 bool _inside;
308 public:
309 ThreadInsideIterationClosure() : _inside(false) {};
310
311 void do_thread(Thread* thread) {
312 _inside |= thread->is_inside_jvmti_env_iteration();
313 }
314
315 bool is_inside_jvmti_env_iteration() {
316 return _inside;
317 }
318 };
319
320 if (_needs_clean_up) {
321 // Check if we are currently iterating environment,
322 // deallocation should not occur if we are
323 ThreadInsideIterationClosure tiic;
324 Threads::threads_do(&tiic);
325 if (!tiic.is_inside_jvmti_env_iteration() &&
326 !is_inside_dying_thread_env_iteration()) {
327 _needs_clean_up = false;
328 JvmtiEnvBase::periodic_clean_up();
329 }
330 }
331 }
332
333
334 void
335 JvmtiEnvBase::record_first_time_class_file_load_hook_enabled() {
336 assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(),
337 "sanity check");
338
339 if (!_class_file_load_hook_ever_enabled) {
340 _class_file_load_hook_ever_enabled = true;
341
342 if (get_capabilities()->can_retransform_classes) {
343 _is_retransformable = true;
344 } else {
345 _is_retransformable = false;
346
347 // cannot add retransform capability after ClassFileLoadHook has been enabled
348 get_prohibited_capabilities()->can_retransform_classes = 1;
349 }
350 }
351 }
352
353
354 void
355 JvmtiEnvBase::record_class_file_load_hook_enabled() {
356 if (!_class_file_load_hook_ever_enabled) {
357 if (Threads::number_of_threads() == 0) {
358 record_first_time_class_file_load_hook_enabled();
359 } else {
360 MutexLocker mu(JvmtiThreadState_lock);
361 record_first_time_class_file_load_hook_enabled();
362 }
363 }
364 }
365
366
367 jvmtiError
368 JvmtiEnvBase::set_native_method_prefixes(jint prefix_count, char** prefixes) {
369 assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(),
370 "sanity check");
371
372 int old_prefix_count = get_native_method_prefix_count();
373 char **old_prefixes = get_native_method_prefixes();
374
375 // allocate and install the new prefixex
376 if (prefix_count == 0 || !is_valid()) {
377 _native_method_prefix_count = 0;
378 _native_method_prefixes = NULL;
379 } else {
380 // there are prefixes, allocate an array to hold them, and fill it
381 char** new_prefixes = (char**)os::malloc((prefix_count) * sizeof(char*), mtInternal);
382 if (new_prefixes == NULL) {
383 return JVMTI_ERROR_OUT_OF_MEMORY;
384 }
385 for (int i = 0; i < prefix_count; i++) {
386 char* prefix = prefixes[i];
387 if (prefix == NULL) {
388 for (int j = 0; j < (i-1); j++) {
389 os::free(new_prefixes[j]);
390 }
391 os::free(new_prefixes);
392 return JVMTI_ERROR_NULL_POINTER;
393 }
394 prefix = os::strdup(prefixes[i]);
395 if (prefix == NULL) {
396 for (int j = 0; j < (i-1); j++) {
397 os::free(new_prefixes[j]);
398 }
399 os::free(new_prefixes);
400 return JVMTI_ERROR_OUT_OF_MEMORY;
401 }
402 new_prefixes[i] = prefix;
403 }
404 _native_method_prefix_count = prefix_count;
405 _native_method_prefixes = new_prefixes;
406 }
407
408 // now that we know the new prefixes have been successfully installed we can
409 // safely remove the old ones
410 if (old_prefix_count != 0) {
411 for (int i = 0; i < old_prefix_count; i++) {
412 os::free(old_prefixes[i]);
413 }
414 os::free(old_prefixes);
415 }
416
417 return JVMTI_ERROR_NONE;
418 }
419
420
421 // Collect all the prefixes which have been set in any JVM TI environments
422 // by the SetNativeMethodPrefix(es) functions. Be sure to maintain the
423 // order of environments and the order of prefixes within each environment.
424 // Return in a resource allocated array.
425 char**
426 JvmtiEnvBase::get_all_native_method_prefixes(int* count_ptr) {
427 assert(Threads::number_of_threads() == 0 ||
428 SafepointSynchronize::is_at_safepoint() ||
429 JvmtiThreadState_lock->is_locked(),
430 "sanity check");
431
432 int total_count = 0;
433 GrowableArray<char*>* prefix_array =new GrowableArray<char*>(5);
434
435 JvmtiEnvIterator it;
436 for (JvmtiEnvBase* env = it.first(); env != NULL; env = it.next(env)) {
437 int prefix_count = env->get_native_method_prefix_count();
438 char** prefixes = env->get_native_method_prefixes();
439 for (int j = 0; j < prefix_count; j++) {
440 // retrieve a prefix and so that it is safe against asynchronous changes
441 // copy it into the resource area
442 char* prefix = prefixes[j];
443 char* prefix_copy = NEW_RESOURCE_ARRAY(char, strlen(prefix)+1);
444 strcpy(prefix_copy, prefix);
445 prefix_array->at_put_grow(total_count++, prefix_copy);
446 }
447 }
448
449 char** all_prefixes = NEW_RESOURCE_ARRAY(char*, total_count);
450 char** p = all_prefixes;
451 for (int i = 0; i < total_count; ++i) {
452 *p++ = prefix_array->at(i);
453 }
454 *count_ptr = total_count;
455 return all_prefixes;
456 }
457
458 void
459 JvmtiEnvBase::set_event_callbacks(const jvmtiEventCallbacks* callbacks,
460 jint size_of_callbacks) {
461 assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(), "sanity check");
462
463 size_t byte_cnt = sizeof(jvmtiEventCallbacks);
464
465 // clear in either case to be sure we got any gap between sizes
466 memset(&_event_callbacks, 0, byte_cnt);
467
468 // Now that JvmtiThreadState_lock is held, prevent a possible race condition where events
469 // are re-enabled by a call to set event callbacks where the DisposeEnvironment
470 // occurs after the boiler-plate environment check and before the lock is acquired.
471 if (callbacks != NULL && is_valid()) {
472 if (size_of_callbacks < (jint)byte_cnt) {
473 byte_cnt = size_of_callbacks;
474 }
475 memcpy(&_event_callbacks, callbacks, byte_cnt);
476 }
477 }
478
479 // Called from JVMTI entry points which perform stack walking. If the
480 // associated JavaThread is the current thread, then wait_for_suspend
481 // is not used. Otherwise, it determines if we should wait for the
482 // "other" thread to complete external suspension. (NOTE: in future
483 // releases the suspension mechanism should be reimplemented so this
484 // is not necessary.)
485 //
486 bool
487 JvmtiEnvBase::is_thread_fully_suspended(JavaThread* thr, bool wait_for_suspend, uint32_t *bits) {
488 // "other" threads require special handling
489 if (thr != JavaThread::current()) {
490 if (wait_for_suspend) {
491 // We are allowed to wait for the external suspend to complete
492 // so give the other thread a chance to get suspended.
493 if (!thr->wait_for_ext_suspend_completion(SuspendRetryCount,
494 SuspendRetryDelay, bits)) {
495 // didn't make it so let the caller know
496 return false;
497 }
498 }
499 // We aren't allowed to wait for the external suspend to complete
500 // so if the other thread isn't externally suspended we need to
501 // let the caller know.
502 else if (!thr->is_ext_suspend_completed_with_lock(bits)) {
503 return false;
504 }
505 }
506
507 return true;
508 }
509
510
511 // In the fullness of time, all users of the method should instead
512 // directly use allocate, besides being cleaner and faster, this will
513 // mean much better out of memory handling
514 unsigned char *
515 JvmtiEnvBase::jvmtiMalloc(jlong size) {
516 unsigned char* mem = NULL;
517 jvmtiError result = allocate(size, &mem);
518 assert(result == JVMTI_ERROR_NONE, "Allocate failed");
519 return mem;
520 }
521
522
523 //
524 // Threads
525 //
526
527 jobject *
528 JvmtiEnvBase::new_jobjectArray(int length, Handle *handles) {
529 if (length == 0) {
530 return NULL;
531 }
532
533 jobject *objArray = (jobject *) jvmtiMalloc(sizeof(jobject) * length);
534 NULL_CHECK(objArray, NULL);
535
536 for (int i=0; i<length; i++) {
537 objArray[i] = jni_reference(handles[i]);
538 }
539 return objArray;
540 }
541
542 jthread *
543 JvmtiEnvBase::new_jthreadArray(int length, Handle *handles) {
544 return (jthread *) new_jobjectArray(length,handles);
545 }
546
547 jthreadGroup *
548 JvmtiEnvBase::new_jthreadGroupArray(int length, Handle *handles) {
549 return (jthreadGroup *) new_jobjectArray(length,handles);
550 }
551
552
553 JavaThread *
554 JvmtiEnvBase::get_JavaThread(jthread jni_thread) {
555 oop t = JNIHandles::resolve_external_guard(jni_thread);
556 if (t == NULL || !t->is_a(SystemDictionary::Thread_klass())) {
557 return NULL;
558 }
559 // The following returns NULL if the thread has not yet run or is in
560 // process of exiting
561 return java_lang_Thread::thread(t);
562 }
563
564
565 // return the vframe on the specified thread and depth, NULL if no such frame
566 vframe*
567 JvmtiEnvBase::vframeFor(JavaThread* java_thread, jint depth) {
568 if (!java_thread->has_last_Java_frame()) {
569 return NULL;
570 }
571 RegisterMap reg_map(java_thread);
572 vframe *vf = java_thread->last_java_vframe(®_map);
573 int d = 0;
574 while ((vf != NULL) && (d < depth)) {
575 vf = vf->java_sender();
576 d++;
577 }
578 return vf;
579 }
580
581
582 //
583 // utilities: JNI objects
584 //
585
586
587 jclass
588 JvmtiEnvBase::get_jni_class_non_null(Klass* k) {
589 assert(k != NULL, "k != NULL");
590 return (jclass)jni_reference(k->java_mirror());
591 }
592
593 //
594 // Field Information
595 //
596
597 bool
598 JvmtiEnvBase::get_field_descriptor(Klass* k, jfieldID field, fieldDescriptor* fd) {
599 if (!jfieldIDWorkaround::is_valid_jfieldID(k, field)) {
600 return false;
601 }
602 bool found = false;
603 if (jfieldIDWorkaround::is_static_jfieldID(field)) {
604 JNIid* id = jfieldIDWorkaround::from_static_jfieldID(field);
605 found = id->find_local_field(fd);
606 } else {
607 // Non-static field. The fieldID is really the offset of the field within the object.
608 int offset = jfieldIDWorkaround::from_instance_jfieldID(k, field);
609 found = InstanceKlass::cast(k)->find_field_from_offset(offset, false, fd);
610 }
611 return found;
612 }
613
614 //
615 // Object Monitor Information
616 //
617
618 //
619 // Count the number of objects for a lightweight monitor. The hobj
620 // parameter is object that owns the monitor so this routine will
621 // count the number of times the same object was locked by frames
622 // in java_thread.
623 //
624 jint
625 JvmtiEnvBase::count_locked_objects(JavaThread *java_thread, Handle hobj) {
626 jint ret = 0;
627 if (!java_thread->has_last_Java_frame()) {
628 return ret; // no Java frames so no monitors
629 }
630
631 ResourceMark rm;
632 HandleMark hm;
633 RegisterMap reg_map(java_thread);
634
635 for(javaVFrame *jvf=java_thread->last_java_vframe(®_map); jvf != NULL;
636 jvf = jvf->java_sender()) {
637 GrowableArray<MonitorInfo*>* mons = jvf->monitors();
638 if (!mons->is_empty()) {
639 for (int i = 0; i < mons->length(); i++) {
640 MonitorInfo *mi = mons->at(i);
641 if (mi->owner_is_scalar_replaced()) continue;
642
643 // see if owner of the monitor is our object
644 if (mi->owner() != NULL && mi->owner() == hobj()) {
645 ret++;
646 }
647 }
648 }
649 }
650 return ret;
651 }
652
653
654
655 jvmtiError
656 JvmtiEnvBase::get_current_contended_monitor(JavaThread *calling_thread, JavaThread *java_thread, jobject *monitor_ptr) {
657 #ifdef ASSERT
658 uint32_t debug_bits = 0;
659 #endif
660 assert((SafepointSynchronize::is_at_safepoint() ||
661 is_thread_fully_suspended(java_thread, false, &debug_bits)),
662 "at safepoint or target thread is suspended");
663 oop obj = NULL;
664 ObjectMonitor *mon = java_thread->current_waiting_monitor();
665 if (mon == NULL) {
666 // thread is not doing an Object.wait() call
667 mon = java_thread->current_pending_monitor();
668 if (mon != NULL) {
669 // The thread is trying to enter() or raw_enter() an ObjectMonitor.
670 obj = (oop)mon->object();
671 // If obj == NULL, then ObjectMonitor is raw which doesn't count
672 // as contended for this API
673 }
674 // implied else: no contended ObjectMonitor
675 } else {
676 // thread is doing an Object.wait() call
677 obj = (oop)mon->object();
678 assert(obj != NULL, "Object.wait() should have an object");
679 }
680
681 if (obj == NULL) {
682 *monitor_ptr = NULL;
683 } else {
684 HandleMark hm;
685 Handle hobj(obj);
686 *monitor_ptr = jni_reference(calling_thread, hobj);
687 }
688 return JVMTI_ERROR_NONE;
689 }
690
691
692 jvmtiError
693 JvmtiEnvBase::get_owned_monitors(JavaThread *calling_thread, JavaThread* java_thread,
694 GrowableArray<jvmtiMonitorStackDepthInfo*> *owned_monitors_list) {
695 jvmtiError err = JVMTI_ERROR_NONE;
696 #ifdef ASSERT
697 uint32_t debug_bits = 0;
698 #endif
699 assert((SafepointSynchronize::is_at_safepoint() ||
700 is_thread_fully_suspended(java_thread, false, &debug_bits)),
701 "at safepoint or target thread is suspended");
702
703 if (java_thread->has_last_Java_frame()) {
704 ResourceMark rm;
705 HandleMark hm;
706 RegisterMap reg_map(java_thread);
707
708 int depth = 0;
709 for (javaVFrame *jvf = java_thread->last_java_vframe(®_map); jvf != NULL;
710 jvf = jvf->java_sender()) {
711 if (depth++ < MaxJavaStackTraceDepth) { // check for stack too deep
712 // add locked objects for this frame into list
713 err = get_locked_objects_in_frame(calling_thread, java_thread, jvf, owned_monitors_list, depth-1);
714 if (err != JVMTI_ERROR_NONE) {
715 return err;
716 }
717 }
718 }
719 }
720
721 // Get off stack monitors. (e.g. acquired via jni MonitorEnter).
722 JvmtiMonitorClosure jmc(java_thread, calling_thread, owned_monitors_list, this);
723 ObjectSynchronizer::monitors_iterate(&jmc);
724 err = jmc.error();
725
726 return err;
727 }
728
729 // Save JNI local handles for any objects that this frame owns.
730 jvmtiError
731 JvmtiEnvBase::get_locked_objects_in_frame(JavaThread* calling_thread, JavaThread* java_thread,
732 javaVFrame *jvf, GrowableArray<jvmtiMonitorStackDepthInfo*>* owned_monitors_list, int stack_depth) {
733 jvmtiError err = JVMTI_ERROR_NONE;
734 ResourceMark rm;
735
736 GrowableArray<MonitorInfo*>* mons = jvf->monitors();
737 if (mons->is_empty()) {
738 return err; // this javaVFrame holds no monitors
739 }
740
741 HandleMark hm;
742 oop wait_obj = NULL;
743 {
744 // save object of current wait() call (if any) for later comparison
745 ObjectMonitor *mon = java_thread->current_waiting_monitor();
746 if (mon != NULL) {
747 wait_obj = (oop)mon->object();
748 }
749 }
750 oop pending_obj = NULL;
751 {
752 // save object of current enter() call (if any) for later comparison
753 ObjectMonitor *mon = java_thread->current_pending_monitor();
754 if (mon != NULL) {
755 pending_obj = (oop)mon->object();
756 }
757 }
758
759 for (int i = 0; i < mons->length(); i++) {
760 MonitorInfo *mi = mons->at(i);
761
762 if (mi->owner_is_scalar_replaced()) continue;
763
764 oop obj = mi->owner();
765 if (obj == NULL) {
766 // this monitor doesn't have an owning object so skip it
767 continue;
768 }
769
770 if (wait_obj == obj) {
771 // the thread is waiting on this monitor so it isn't really owned
772 continue;
773 }
774
775 if (pending_obj == obj) {
776 // the thread is pending on this monitor so it isn't really owned
777 continue;
778 }
779
780 if (owned_monitors_list->length() > 0) {
781 // Our list has at least one object on it so we have to check
782 // for recursive object locking
783 bool found = false;
784 for (int j = 0; j < owned_monitors_list->length(); j++) {
785 jobject jobj = ((jvmtiMonitorStackDepthInfo*)owned_monitors_list->at(j))->monitor;
786 oop check = JNIHandles::resolve(jobj);
787 if (check == obj) {
788 found = true; // we found the object
789 break;
790 }
791 }
792
793 if (found) {
794 // already have this object so don't include it
795 continue;
796 }
797 }
798
799 // add the owning object to our list
800 jvmtiMonitorStackDepthInfo *jmsdi;
801 err = allocate(sizeof(jvmtiMonitorStackDepthInfo), (unsigned char **)&jmsdi);
802 if (err != JVMTI_ERROR_NONE) {
803 return err;
804 }
805 Handle hobj(obj);
806 jmsdi->monitor = jni_reference(calling_thread, hobj);
807 jmsdi->stack_depth = stack_depth;
808 owned_monitors_list->append(jmsdi);
809 }
810
811 return err;
812 }
813
814 jvmtiError
815 JvmtiEnvBase::get_stack_trace(JavaThread *java_thread,
816 jint start_depth, jint max_count,
817 jvmtiFrameInfo* frame_buffer, jint* count_ptr) {
818 #ifdef ASSERT
819 uint32_t debug_bits = 0;
820 #endif
821 assert((SafepointSynchronize::is_at_safepoint() ||
822 is_thread_fully_suspended(java_thread, false, &debug_bits)),
823 "at safepoint or target thread is suspended");
824 int count = 0;
825 if (java_thread->has_last_Java_frame()) {
826 RegisterMap reg_map(java_thread);
827 Thread* current_thread = Thread::current();
828 ResourceMark rm(current_thread);
829 javaVFrame *jvf = java_thread->last_java_vframe(®_map);
830 HandleMark hm(current_thread);
831 if (start_depth != 0) {
832 if (start_depth > 0) {
833 for (int j = 0; j < start_depth && jvf != NULL; j++) {
834 jvf = jvf->java_sender();
835 }
836 if (jvf == NULL) {
837 // start_depth is deeper than the stack depth
838 return JVMTI_ERROR_ILLEGAL_ARGUMENT;
839 }
840 } else { // start_depth < 0
841 // we are referencing the starting depth based on the oldest
842 // part of the stack.
843 // optimize to limit the number of times that java_sender() is called
844 javaVFrame *jvf_cursor = jvf;
845 javaVFrame *jvf_prev = NULL;
846 javaVFrame *jvf_prev_prev = NULL;
847 int j = 0;
848 while (jvf_cursor != NULL) {
849 jvf_prev_prev = jvf_prev;
850 jvf_prev = jvf_cursor;
851 for (j = 0; j > start_depth && jvf_cursor != NULL; j--) {
852 jvf_cursor = jvf_cursor->java_sender();
853 }
854 }
855 if (j == start_depth) {
856 // previous pointer is exactly where we want to start
857 jvf = jvf_prev;
858 } else {
859 // we need to back up further to get to the right place
860 if (jvf_prev_prev == NULL) {
861 // the -start_depth is greater than the stack depth
862 return JVMTI_ERROR_ILLEGAL_ARGUMENT;
863 }
864 // j now is the number of frames on the stack starting with
865 // jvf_prev, we start from jvf_prev_prev and move older on
866 // the stack that many, the result is -start_depth frames
867 // remaining.
868 jvf = jvf_prev_prev;
869 for (; j < 0; j++) {
870 jvf = jvf->java_sender();
871 }
872 }
873 }
874 }
875 for (; count < max_count && jvf != NULL; count++) {
876 frame_buffer[count].method = jvf->method()->jmethod_id();
877 frame_buffer[count].location = (jvf->method()->is_native() ? -1 : jvf->bci());
878 jvf = jvf->java_sender();
879 }
880 } else {
881 if (start_depth != 0) {
882 // no frames and there is a starting depth
883 return JVMTI_ERROR_ILLEGAL_ARGUMENT;
884 }
885 }
886 *count_ptr = count;
887 return JVMTI_ERROR_NONE;
888 }
889
890 jvmtiError
891 JvmtiEnvBase::get_frame_count(JvmtiThreadState *state, jint *count_ptr) {
892 assert((state != NULL),
893 "JavaThread should create JvmtiThreadState before calling this method");
894 *count_ptr = state->count_frames();
895 return JVMTI_ERROR_NONE;
896 }
897
898 jvmtiError
899 JvmtiEnvBase::get_frame_location(JavaThread *java_thread, jint depth,
900 jmethodID* method_ptr, jlocation* location_ptr) {
901 #ifdef ASSERT
902 uint32_t debug_bits = 0;
903 #endif
904 assert((SafepointSynchronize::is_at_safepoint() ||
905 is_thread_fully_suspended(java_thread, false, &debug_bits)),
906 "at safepoint or target thread is suspended");
907 Thread* current_thread = Thread::current();
908 ResourceMark rm(current_thread);
909
910 vframe *vf = vframeFor(java_thread, depth);
911 if (vf == NULL) {
912 return JVMTI_ERROR_NO_MORE_FRAMES;
913 }
914
915 // vframeFor should return a java frame. If it doesn't
916 // it means we've got an internal error and we return the
917 // error in product mode. In debug mode we will instead
918 // attempt to cast the vframe to a javaVFrame and will
919 // cause an assertion/crash to allow further diagnosis.
920 #ifdef PRODUCT
921 if (!vf->is_java_frame()) {
922 return JVMTI_ERROR_INTERNAL;
923 }
924 #endif
925
926 HandleMark hm(current_thread);
927 javaVFrame *jvf = javaVFrame::cast(vf);
928 Method* method = jvf->method();
929 if (method->is_native()) {
930 *location_ptr = -1;
931 } else {
932 *location_ptr = jvf->bci();
933 }
934 *method_ptr = method->jmethod_id();
935
936 return JVMTI_ERROR_NONE;
937 }
938
939
940 jvmtiError
941 JvmtiEnvBase::get_object_monitor_usage(JavaThread* calling_thread, jobject object, jvmtiMonitorUsage* info_ptr) {
942 HandleMark hm;
943 Handle hobj;
944
945 bool at_safepoint = SafepointSynchronize::is_at_safepoint();
946
947 // Check arguments
948 {
949 oop mirror = JNIHandles::resolve_external_guard(object);
950 NULL_CHECK(mirror, JVMTI_ERROR_INVALID_OBJECT);
951 NULL_CHECK(info_ptr, JVMTI_ERROR_NULL_POINTER);
952
953 hobj = Handle(mirror);
954 }
955
956 JavaThread *owning_thread = NULL;
957 ObjectMonitor *mon = NULL;
958 jvmtiMonitorUsage ret = {
959 NULL, 0, 0, NULL, 0, NULL
960 };
961
962 uint32_t debug_bits = 0;
963 // first derive the object's owner and entry_count (if any)
964 {
965 // Revoke any biases before querying the mark word
966 if (SafepointSynchronize::is_at_safepoint()) {
967 BiasedLocking::revoke_at_safepoint(hobj);
968 } else {
969 BiasedLocking::revoke_and_rebias(hobj, false, calling_thread);
970 }
971
972 address owner = NULL;
973 {
974 markOop mark = hobj()->mark();
975
976 if (!mark->has_monitor()) {
977 // this object has a lightweight monitor
978
979 if (mark->has_locker()) {
980 owner = (address)mark->locker(); // save the address of the Lock word
981 }
982 // implied else: no owner
983 } else {
984 // this object has a heavyweight monitor
985 mon = mark->monitor();
986
987 // The owner field of a heavyweight monitor may be NULL for no
988 // owner, a JavaThread * or it may still be the address of the
989 // Lock word in a JavaThread's stack. A monitor can be inflated
990 // by a non-owning JavaThread, but only the owning JavaThread
991 // can change the owner field from the Lock word to the
992 // JavaThread * and it may not have done that yet.
993 owner = (address)mon->owner();
994 }
995 }
996
997 if (owner != NULL) {
998 // This monitor is owned so we have to find the owning JavaThread.
999 // Since owning_thread_from_monitor_owner() grabs a lock, GC can
1000 // move our object at this point. However, our owner value is safe
1001 // since it is either the Lock word on a stack or a JavaThread *.
1002 owning_thread = Threads::owning_thread_from_monitor_owner(owner, !at_safepoint);
1003 // Cannot assume (owning_thread != NULL) here because this function
1004 // may not have been called at a safepoint and the owning_thread
1005 // might not be suspended.
1006 if (owning_thread != NULL) {
1007 // The monitor's owner either has to be the current thread, at safepoint
1008 // or it has to be suspended. Any of these conditions will prevent both
1009 // contending and waiting threads from modifying the state of
1010 // the monitor.
1011 if (!at_safepoint && !JvmtiEnv::is_thread_fully_suspended(owning_thread, true, &debug_bits)) {
1012 // Don't worry! This return of JVMTI_ERROR_THREAD_NOT_SUSPENDED
1013 // will not make it back to the JVM/TI agent. The error code will
1014 // get intercepted in JvmtiEnv::GetObjectMonitorUsage() which
1015 // will retry the call via a VM_GetObjectMonitorUsage VM op.
1016 return JVMTI_ERROR_THREAD_NOT_SUSPENDED;
1017 }
1018 HandleMark hm;
1019 Handle th(owning_thread->threadObj());
1020 ret.owner = (jthread)jni_reference(calling_thread, th);
1021 }
1022 // implied else: no owner
1023 }
1024
1025 if (owning_thread != NULL) { // monitor is owned
1026 // The recursions field of a monitor does not reflect recursions
1027 // as lightweight locks before inflating the monitor are not included.
1028 // We have to count the number of recursive monitor entries the hard way.
1029 // We pass a handle to survive any GCs along the way.
1030 ResourceMark rm;
1031 ret.entry_count = count_locked_objects(owning_thread, hobj);
1032 }
1033 // implied else: entry_count == 0
1034 }
1035
1036 jint nWant = 0, nWait = 0;
1037 if (mon != NULL) {
1038 // this object has a heavyweight monitor
1039 nWant = mon->contentions(); // # of threads contending for monitor
1040 nWait = mon->waiters(); // # of threads in Object.wait()
1041 ret.waiter_count = nWant + nWait;
1042 ret.notify_waiter_count = nWait;
1043 } else {
1044 // this object has a lightweight monitor
1045 ret.waiter_count = 0;
1046 ret.notify_waiter_count = 0;
1047 }
1048
1049 // Allocate memory for heavyweight and lightweight monitor.
1050 jvmtiError err;
1051 err = allocate(ret.waiter_count * sizeof(jthread *), (unsigned char**)&ret.waiters);
1052 if (err != JVMTI_ERROR_NONE) {
1053 return err;
1054 }
1055 err = allocate(ret.notify_waiter_count * sizeof(jthread *),
1056 (unsigned char**)&ret.notify_waiters);
1057 if (err != JVMTI_ERROR_NONE) {
1058 deallocate((unsigned char*)ret.waiters);
1059 return err;
1060 }
1061
1062 // now derive the rest of the fields
1063 if (mon != NULL) {
1064 // this object has a heavyweight monitor
1065
1066 // Number of waiters may actually be less than the waiter count.
1067 // So NULL out memory so that unused memory will be NULL.
1068 memset(ret.waiters, 0, ret.waiter_count * sizeof(jthread *));
1069 memset(ret.notify_waiters, 0, ret.notify_waiter_count * sizeof(jthread *));
1070
1071 if (ret.waiter_count > 0) {
1072 // we have contending and/or waiting threads
1073 HandleMark hm;
1074 if (nWant > 0) {
1075 // we have contending threads
1076 ResourceMark rm;
1077 // get_pending_threads returns only java thread so we do not need to
1078 // check for non java threads.
1079 GrowableArray<JavaThread*>* wantList = Threads::get_pending_threads(
1080 nWant, (address)mon, !at_safepoint);
1081 if (wantList->length() < nWant) {
1082 // robustness: the pending list has gotten smaller
1083 nWant = wantList->length();
1084 }
1085 for (int i = 0; i < nWant; i++) {
1086 JavaThread *pending_thread = wantList->at(i);
1087 // If the monitor has no owner, then a non-suspended contending
1088 // thread could potentially change the state of the monitor by
1089 // entering it. The JVM/TI spec doesn't allow this.
1090 if (owning_thread == NULL && !at_safepoint &
1091 !JvmtiEnv::is_thread_fully_suspended(pending_thread, true, &debug_bits)) {
1092 if (ret.owner != NULL) {
1093 destroy_jni_reference(calling_thread, ret.owner);
1094 }
1095 for (int j = 0; j < i; j++) {
1096 destroy_jni_reference(calling_thread, ret.waiters[j]);
1097 }
1098 deallocate((unsigned char*)ret.waiters);
1099 deallocate((unsigned char*)ret.notify_waiters);
1100 return JVMTI_ERROR_THREAD_NOT_SUSPENDED;
1101 }
1102 Handle th(pending_thread->threadObj());
1103 ret.waiters[i] = (jthread)jni_reference(calling_thread, th);
1104 }
1105 }
1106 if (nWait > 0) {
1107 // we have threads in Object.wait()
1108 int offset = nWant; // add after any contending threads
1109 ObjectWaiter *waiter = mon->first_waiter();
1110 for (int i = 0, j = 0; i < nWait; i++) {
1111 if (waiter == NULL) {
1112 // robustness: the waiting list has gotten smaller
1113 nWait = j;
1114 break;
1115 }
1116 Thread *t = mon->thread_of_waiter(waiter);
1117 if (t != NULL && t->is_Java_thread()) {
1118 JavaThread *wjava_thread = (JavaThread *)t;
1119 // If the thread was found on the ObjectWaiter list, then
1120 // it has not been notified. This thread can't change the
1121 // state of the monitor so it doesn't need to be suspended.
1122 Handle th(wjava_thread->threadObj());
1123 ret.waiters[offset + j] = (jthread)jni_reference(calling_thread, th);
1124 ret.notify_waiters[j++] = (jthread)jni_reference(calling_thread, th);
1125 }
1126 waiter = mon->next_waiter(waiter);
1127 }
1128 }
1129 }
1130
1131 // Adjust count. nWant and nWait count values may be less than original.
1132 ret.waiter_count = nWant + nWait;
1133 ret.notify_waiter_count = nWait;
1134 } else {
1135 // this object has a lightweight monitor and we have nothing more
1136 // to do here because the defaults are just fine.
1137 }
1138
1139 // we don't update return parameter unless everything worked
1140 *info_ptr = ret;
1141
1142 return JVMTI_ERROR_NONE;
1143 }
1144
1145 ResourceTracker::ResourceTracker(JvmtiEnv* env) {
1146 _env = env;
1147 _allocations = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<unsigned char*>(20, true);
1148 _failed = false;
1149 }
1150 ResourceTracker::~ResourceTracker() {
1151 if (_failed) {
1152 for (int i=0; i<_allocations->length(); i++) {
1153 _env->deallocate(_allocations->at(i));
1154 }
1155 }
1156 delete _allocations;
1157 }
1158
1159 jvmtiError ResourceTracker::allocate(jlong size, unsigned char** mem_ptr) {
1160 unsigned char *ptr;
1161 jvmtiError err = _env->allocate(size, &ptr);
1162 if (err == JVMTI_ERROR_NONE) {
1163 _allocations->append(ptr);
1164 *mem_ptr = ptr;
1165 } else {
1166 *mem_ptr = NULL;
1167 _failed = true;
1168 }
1169 return err;
1170 }
1171
1172 unsigned char* ResourceTracker::allocate(jlong size) {
1173 unsigned char* ptr;
1174 allocate(size, &ptr);
1175 return ptr;
1176 }
1177
1178 char* ResourceTracker::strdup(const char* str) {
1179 char *dup_str = (char*)allocate(strlen(str)+1);
1180 if (dup_str != NULL) {
1181 strcpy(dup_str, str);
1182 }
1183 return dup_str;
1184 }
1185
1186 struct StackInfoNode {
1187 struct StackInfoNode *next;
1188 jvmtiStackInfo info;
1189 };
1190
1191 // Create a jvmtiStackInfo inside a linked list node and create a
1192 // buffer for the frame information, both allocated as resource objects.
1193 // Fill in both the jvmtiStackInfo and the jvmtiFrameInfo.
1194 // Note that either or both of thr and thread_oop
1195 // may be null if the thread is new or has exited.
1196 void
1197 VM_GetMultipleStackTraces::fill_frames(jthread jt, JavaThread *thr, oop thread_oop) {
1198 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
1199
1200 jint state = 0;
1201 struct StackInfoNode *node = NEW_RESOURCE_OBJ(struct StackInfoNode);
1202 jvmtiStackInfo *infop = &(node->info);
1203 node->next = head();
1204 set_head(node);
1205 infop->frame_count = 0;
1206 infop->thread = jt;
1207
1208 if (thread_oop != NULL) {
1209 // get most state bits
1210 state = (jint)java_lang_Thread::get_thread_status(thread_oop);
1211 }
1212
1213 if (thr != NULL) { // add more state bits if there is a JavaThead to query
1214 // same as is_being_ext_suspended() but without locking
1215 if (thr->is_ext_suspended() || thr->is_external_suspend()) {
1216 state |= JVMTI_THREAD_STATE_SUSPENDED;
1217 }
1218 JavaThreadState jts = thr->thread_state();
1219 if (jts == _thread_in_native) {
1220 state |= JVMTI_THREAD_STATE_IN_NATIVE;
1221 }
1222 OSThread* osThread = thr->osthread();
1223 if (osThread != NULL && osThread->interrupted()) {
1224 state |= JVMTI_THREAD_STATE_INTERRUPTED;
1225 }
1226 }
1227 infop->state = state;
1228
1229 if (thr != NULL || (state & JVMTI_THREAD_STATE_ALIVE) != 0) {
1230 infop->frame_buffer = NEW_RESOURCE_ARRAY(jvmtiFrameInfo, max_frame_count());
1231 env()->get_stack_trace(thr, 0, max_frame_count(),
1232 infop->frame_buffer, &(infop->frame_count));
1233 } else {
1234 infop->frame_buffer = NULL;
1235 infop->frame_count = 0;
1236 }
1237 _frame_count_total += infop->frame_count;
1238 }
1239
1240 // Based on the stack information in the linked list, allocate memory
1241 // block to return and fill it from the info in the linked list.
1242 void
1243 VM_GetMultipleStackTraces::allocate_and_fill_stacks(jint thread_count) {
1244 // do I need to worry about alignment issues?
1245 jlong alloc_size = thread_count * sizeof(jvmtiStackInfo)
1246 + _frame_count_total * sizeof(jvmtiFrameInfo);
1247 env()->allocate(alloc_size, (unsigned char **)&_stack_info);
1248
1249 // pointers to move through the newly allocated space as it is filled in
1250 jvmtiStackInfo *si = _stack_info + thread_count; // bottom of stack info
1251 jvmtiFrameInfo *fi = (jvmtiFrameInfo *)si; // is the top of frame info
1252
1253 // copy information in resource area into allocated buffer
1254 // insert stack info backwards since linked list is backwards
1255 // insert frame info forwards
1256 // walk the StackInfoNodes
1257 for (struct StackInfoNode *sin = head(); sin != NULL; sin = sin->next) {
1258 jint frame_count = sin->info.frame_count;
1259 size_t frames_size = frame_count * sizeof(jvmtiFrameInfo);
1260 --si;
1261 memcpy(si, &(sin->info), sizeof(jvmtiStackInfo));
1262 if (frames_size == 0) {
1263 si->frame_buffer = NULL;
1264 } else {
1265 memcpy(fi, sin->info.frame_buffer, frames_size);
1266 si->frame_buffer = fi; // point to the new allocated copy of the frames
1267 fi += frame_count;
1268 }
1269 }
1270 assert(si == _stack_info, "the last copied stack info must be the first record");
1271 assert((unsigned char *)fi == ((unsigned char *)_stack_info) + alloc_size,
1272 "the last copied frame info must be the last record");
1273 }
1274
1275
1276 void
1277 VM_GetThreadListStackTraces::doit() {
1278 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
1279
1280 ResourceMark rm;
1281 for (int i = 0; i < _thread_count; ++i) {
1282 jthread jt = _thread_list[i];
1283 oop thread_oop = JNIHandles::resolve_external_guard(jt);
1284 if (thread_oop == NULL || !thread_oop->is_a(SystemDictionary::Thread_klass())) {
1285 set_result(JVMTI_ERROR_INVALID_THREAD);
1286 return;
1287 }
1288 fill_frames(jt, java_lang_Thread::thread(thread_oop), thread_oop);
1289 }
1290 allocate_and_fill_stacks(_thread_count);
1291 }
1292
1293 void
1294 VM_GetAllStackTraces::doit() {
1295 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
1296
1297 ResourceMark rm;
1298 _final_thread_count = 0;
1299 for (JavaThread *jt = Threads::first(); jt != NULL; jt = jt->next()) {
1300 oop thread_oop = jt->threadObj();
1301 if (thread_oop != NULL &&
1302 !jt->is_exiting() &&
1303 java_lang_Thread::is_alive(thread_oop) &&
1304 !jt->is_hidden_from_external_view()) {
1305 ++_final_thread_count;
1306 // Handle block of the calling thread is used to create local refs.
1307 fill_frames((jthread)JNIHandles::make_local(_calling_thread, thread_oop),
1308 jt, thread_oop);
1309 }
1310 }
1311 allocate_and_fill_stacks(_final_thread_count);
1312 }
1313
1314 // Verifies that the top frame is a java frame in an expected state.
1315 // Deoptimizes frame if needed.
1316 // Checks that the frame method signature matches the return type (tos).
1317 // HandleMark must be defined in the caller only.
1318 // It is to keep a ret_ob_h handle alive after return to the caller.
1319 jvmtiError
1320 JvmtiEnvBase::check_top_frame(JavaThread* current_thread, JavaThread* java_thread,
1321 jvalue value, TosState tos, Handle* ret_ob_h) {
1322 ResourceMark rm(current_thread);
1323
1324 vframe *vf = vframeFor(java_thread, 0);
1325 NULL_CHECK(vf, JVMTI_ERROR_NO_MORE_FRAMES);
1326
1327 javaVFrame *jvf = (javaVFrame*) vf;
1328 if (!vf->is_java_frame() || jvf->method()->is_native()) {
1329 return JVMTI_ERROR_OPAQUE_FRAME;
1330 }
1331
1332 // If the frame is a compiled one, need to deoptimize it.
1333 if (vf->is_compiled_frame()) {
1334 if (!vf->fr().can_be_deoptimized()) {
1335 return JVMTI_ERROR_OPAQUE_FRAME;
1336 }
1337 Deoptimization::deoptimize_frame(java_thread, jvf->fr().id());
1338 }
1339
1340 // Get information about method return type
1341 Symbol* signature = jvf->method()->signature();
1342
1343 ResultTypeFinder rtf(signature);
1344 TosState fr_tos = as_TosState(rtf.type());
1345 if (fr_tos != tos) {
1346 if (tos != itos || (fr_tos != btos && fr_tos != ctos && fr_tos != stos)) {
1347 return JVMTI_ERROR_TYPE_MISMATCH;
1348 }
1349 }
1350
1351 // Check that the jobject class matches the return type signature.
1352 jobject jobj = value.l;
1353 if (tos == atos && jobj != NULL) { // NULL reference is allowed
1354 Handle ob_h = Handle(current_thread, JNIHandles::resolve_external_guard(jobj));
1355 NULL_CHECK(ob_h, JVMTI_ERROR_INVALID_OBJECT);
1356 KlassHandle ob_kh = KlassHandle(current_thread, ob_h()->klass());
1357 NULL_CHECK(ob_kh, JVMTI_ERROR_INVALID_OBJECT);
1358
1359 // Method return type signature.
1360 char* ty_sign = 1 + strchr(signature->as_C_string(), ')');
1361
1362 if (!VM_GetOrSetLocal::is_assignable(ty_sign, ob_kh(), current_thread)) {
1363 return JVMTI_ERROR_TYPE_MISMATCH;
1364 }
1365 *ret_ob_h = ob_h;
1366 }
1367 return JVMTI_ERROR_NONE;
1368 } /* end check_top_frame */
1369
1370
1371 // ForceEarlyReturn<type> follows the PopFrame approach in many aspects.
1372 // Main difference is on the last stage in the interpreter.
1373 // The PopFrame stops method execution to continue execution
1374 // from the same method call instruction.
1375 // The ForceEarlyReturn forces return from method so the execution
1376 // continues at the bytecode following the method call.
1377
1378 // Threads_lock NOT held, java_thread not protected by lock
1379 // java_thread - pre-checked
1380
1381 jvmtiError
1382 JvmtiEnvBase::force_early_return(JavaThread* java_thread, jvalue value, TosState tos) {
1383 JavaThread* current_thread = JavaThread::current();
1384 HandleMark hm(current_thread);
1385 uint32_t debug_bits = 0;
1386
1387 // retrieve or create the state
1388 JvmtiThreadState* state = JvmtiThreadState::state_for(java_thread);
1389 if (state == NULL) {
1390 return JVMTI_ERROR_THREAD_NOT_ALIVE;
1391 }
1392
1393 // Check if java_thread is fully suspended
1394 if (!is_thread_fully_suspended(java_thread,
1395 true /* wait for suspend completion */,
1396 &debug_bits)) {
1397 return JVMTI_ERROR_THREAD_NOT_SUSPENDED;
1398 }
1399
1400 // Check to see if a ForceEarlyReturn was already in progress
1401 if (state->is_earlyret_pending()) {
1402 // Probably possible for JVMTI clients to trigger this, but the
1403 // JPDA backend shouldn't allow this to happen
1404 return JVMTI_ERROR_INTERNAL;
1405 }
1406 {
1407 // The same as for PopFrame. Workaround bug:
1408 // 4812902: popFrame hangs if the method is waiting at a synchronize
1409 // Catch this condition and return an error to avoid hanging.
1410 // Now JVMTI spec allows an implementation to bail out with an opaque
1411 // frame error.
1412 OSThread* osThread = java_thread->osthread();
1413 if (osThread->get_state() == MONITOR_WAIT) {
1414 return JVMTI_ERROR_OPAQUE_FRAME;
1415 }
1416 }
1417 Handle ret_ob_h = Handle();
1418 jvmtiError err = check_top_frame(current_thread, java_thread, value, tos, &ret_ob_h);
1419 if (err != JVMTI_ERROR_NONE) {
1420 return err;
1421 }
1422 assert(tos != atos || value.l == NULL || ret_ob_h() != NULL,
1423 "return object oop must not be NULL if jobject is not NULL");
1424
1425 // Update the thread state to reflect that the top frame must be
1426 // forced to return.
1427 // The current frame will be returned later when the suspended
1428 // thread is resumed and right before returning from VM to Java.
1429 // (see call_VM_base() in assembler_<cpu>.cpp).
1430
1431 state->set_earlyret_pending();
1432 state->set_earlyret_oop(ret_ob_h());
1433 state->set_earlyret_value(value, tos);
1434
1435 // Set pending step flag for this early return.
1436 // It is cleared when next step event is posted.
1437 state->set_pending_step_for_earlyret();
1438
1439 return JVMTI_ERROR_NONE;
1440 } /* end force_early_return */
1441
1442 void
1443 JvmtiMonitorClosure::do_monitor(ObjectMonitor* mon) {
1444 if ( _error != JVMTI_ERROR_NONE) {
1445 // Error occurred in previous iteration so no need to add
1446 // to the list.
1447 return;
1448 }
1449 if (mon->owner() == _java_thread ) {
1450 // Filter out on stack monitors collected during stack walk.
1451 oop obj = (oop)mon->object();
1452 bool found = false;
1453 for (int j = 0; j < _owned_monitors_list->length(); j++) {
1454 jobject jobj = ((jvmtiMonitorStackDepthInfo*)_owned_monitors_list->at(j))->monitor;
1455 oop check = JNIHandles::resolve(jobj);
1456 if (check == obj) {
1457 // On stack monitor already collected during the stack walk.
1458 found = true;
1459 break;
1460 }
1461 }
1462 if (found == false) {
1463 // This is off stack monitor (e.g. acquired via jni MonitorEnter).
1464 jvmtiError err;
1465 jvmtiMonitorStackDepthInfo *jmsdi;
1466 err = _env->allocate(sizeof(jvmtiMonitorStackDepthInfo), (unsigned char **)&jmsdi);
1467 if (err != JVMTI_ERROR_NONE) {
1468 _error = err;
1469 return;
1470 }
1471 Handle hobj(obj);
1472 jmsdi->monitor = _env->jni_reference(_calling_thread, hobj);
1473 // stack depth is unknown for this monitor.
1474 jmsdi->stack_depth = -1;
1475 _owned_monitors_list->append(jmsdi);
1476 }
1477 }
1478 }