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src/hotspot/share/prims/jvmtiManageCapabilities.cpp

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  1 /*
  2  * Copyright (c) 2003, 2025, 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  *

 39   // capabilities which are always potentially available
 40   // but to only one environment
 41 jvmtiCapabilities JvmtiManageCapabilities::always_solo_capabilities;
 42 
 43   // capabilities which are potentially available during OnLoad
 44   // but to only one environment
 45 jvmtiCapabilities JvmtiManageCapabilities::onload_solo_capabilities;
 46 
 47   // remaining capabilities which are always potentially available
 48   // but to only one environment
 49 jvmtiCapabilities JvmtiManageCapabilities::always_solo_remaining_capabilities;
 50 
 51   // remaining capabilities which are potentially available during OnLoad
 52   // but to only one environment
 53 jvmtiCapabilities JvmtiManageCapabilities::onload_solo_remaining_capabilities;
 54 
 55   // all capabilities ever acquired
 56 jvmtiCapabilities JvmtiManageCapabilities::acquired_capabilities;
 57 
 58 int JvmtiManageCapabilities::_can_support_virtual_threads_count = 0;

 59 
 60 Mutex* JvmtiManageCapabilities::_capabilities_lock = nullptr;
 61 
 62 void JvmtiManageCapabilities::initialize() {
 63   _capabilities_lock = new Mutex(Mutex::nosafepoint, "Capabilities_lock");
 64   always_capabilities = init_always_capabilities();
 65   onload_capabilities = init_onload_capabilities();
 66   always_solo_capabilities = init_always_solo_capabilities();
 67   onload_solo_capabilities = init_onload_solo_capabilities();
 68   always_solo_remaining_capabilities = init_always_solo_capabilities();
 69   onload_solo_remaining_capabilities = init_onload_solo_capabilities();
 70   memset(&acquired_capabilities, 0, sizeof(acquired_capabilities));
 71 }
 72 
 73 
 74 // corresponding init functions
 75 jvmtiCapabilities JvmtiManageCapabilities::init_always_capabilities() {
 76   jvmtiCapabilities jc;
 77 
 78   memset(&jc, 0, sizeof(jc));

 86   jc.can_generate_all_class_hook_events = 1;
 87   jc.can_generate_monitor_events = 1;
 88   jc.can_generate_garbage_collection_events = 1;
 89   jc.can_generate_compiled_method_load_events = 1;
 90   jc.can_generate_native_method_bind_events = 1;
 91   jc.can_generate_vm_object_alloc_events = 1;
 92   if (os::is_thread_cpu_time_supported()) {
 93     jc.can_get_current_thread_cpu_time = 1;
 94     jc.can_get_thread_cpu_time = 1;
 95   }
 96   jc.can_redefine_classes = 1;
 97   jc.can_redefine_any_class = 1;
 98   jc.can_retransform_classes = 1;
 99   jc.can_retransform_any_class = 1;
100   jc.can_set_native_method_prefix = 1;
101   jc.can_tag_objects = 1;
102   jc.can_generate_object_free_events = 1;
103   jc.can_generate_resource_exhaustion_heap_events = 1;
104   jc.can_generate_resource_exhaustion_threads_events = 1;
105   jc.can_support_virtual_threads = 1;

106   return jc;
107 }
108 
109 jvmtiCapabilities JvmtiManageCapabilities::init_onload_capabilities() {
110   jvmtiCapabilities jc;
111 
112   memset(&jc, 0, sizeof(jc));
113 #ifndef ZERO
114   jc.can_pop_frame = 1;
115   jc.can_force_early_return = 1;
116 #endif // !ZERO
117   jc.can_get_source_debug_extension = 1;
118   jc.can_access_local_variables = 1;
119   jc.can_maintain_original_method_order = 1;
120   jc.can_generate_single_step_events = 1;
121   jc.can_generate_exception_events = 1;
122   jc.can_generate_frame_pop_events = 1;
123   jc.can_generate_method_entry_events = 1;
124   jc.can_generate_method_exit_events = 1;
125   jc.can_get_owned_monitor_info = 1;

260   // add to the set of ever acquired capabilities
261   either(&acquired_capabilities, desired, &acquired_capabilities);
262 
263   // onload capabilities that got added are now permanent - so, also remove from onload
264   both(&onload_capabilities, desired, &temp);
265   either(&always_capabilities, &temp, &always_capabilities);
266   exclude(&onload_capabilities, &temp, &onload_capabilities);
267 
268   // same for solo capabilities (transferred capabilities in the remaining sets handled as part of standard grab - below)
269   both(&onload_solo_capabilities, desired, &temp);
270   either(&always_solo_capabilities, &temp, &always_solo_capabilities);
271   exclude(&onload_solo_capabilities, &temp, &onload_solo_capabilities);
272 
273   // remove solo capabilities that are now taken
274   exclude(&always_solo_remaining_capabilities, desired, &always_solo_remaining_capabilities);
275   exclude(&onload_solo_remaining_capabilities, desired, &onload_solo_remaining_capabilities);
276 
277   if (desired->can_support_virtual_threads != 0 && current->can_support_virtual_threads == 0) {
278     _can_support_virtual_threads_count++;
279   }



280 
281   // return the result
282   either(current, desired, result);
283 
284   update();
285 
286   return JVMTI_ERROR_NONE;
287 }
288 
289 
290 void JvmtiManageCapabilities::relinquish_capabilities(const jvmtiCapabilities *current,
291                                                       const jvmtiCapabilities *unwanted,
292                                                       jvmtiCapabilities *result) {
293   CapabilitiesMutexLocker ml;
294 
295   jvmtiCapabilities to_trash;
296   jvmtiCapabilities temp;
297 
298   // can't give up what you don't have
299   both(current, unwanted, &to_trash);
300 
301   // restore solo capabilities but only those that belong
302   either(&always_solo_remaining_capabilities, both(&always_solo_capabilities, &to_trash, &temp),
303          &always_solo_remaining_capabilities);
304   either(&onload_solo_remaining_capabilities, both(&onload_solo_capabilities, &to_trash, &temp),
305          &onload_solo_remaining_capabilities);
306 
307   if (to_trash.can_support_virtual_threads != 0) {
308     assert(current->can_support_virtual_threads != 0, "sanity check");
309     assert(_can_support_virtual_threads_count > 0, "sanity check");
310     _can_support_virtual_threads_count--;
311   }





312 
313   update();
314 
315   // return the result
316   exclude(current, unwanted, result);
317 }
318 
319 
320 void JvmtiManageCapabilities::update() {
321   jvmtiCapabilities avail;
322 
323   // all capabilities
324   either(&always_capabilities, &always_solo_capabilities, &avail);
325 
326   bool interp_events =
327     avail.can_generate_field_access_events ||
328     avail.can_generate_field_modification_events ||
329     avail.can_generate_single_step_events ||
330     avail.can_generate_method_entry_events ||
331     avail.can_generate_method_exit_events;

376   // improve the debugging experience so only set them if the selected
377   // capabilities look like a debugger.
378   JvmtiExport::set_can_access_local_variables(
379     avail.can_access_local_variables ||
380     avail.can_generate_breakpoint_events ||
381     avail.can_generate_frame_pop_events);
382   JvmtiExport::set_can_post_on_exceptions(
383     avail.can_generate_exception_events ||
384     avail.can_generate_frame_pop_events ||
385     avail.can_generate_method_exit_events);
386   JvmtiExport::set_can_post_breakpoint(avail.can_generate_breakpoint_events);
387   JvmtiExport::set_can_post_field_access(avail.can_generate_field_access_events);
388   JvmtiExport::set_can_post_field_modification(avail.can_generate_field_modification_events);
389   JvmtiExport::set_can_post_method_entry(avail.can_generate_method_entry_events);
390   JvmtiExport::set_can_post_method_exit(avail.can_generate_method_exit_events ||
391                                         avail.can_generate_frame_pop_events);
392   JvmtiExport::set_can_post_frame_pop(avail.can_generate_frame_pop_events);
393   JvmtiExport::set_can_pop_frame(avail.can_pop_frame);
394   JvmtiExport::set_can_force_early_return(avail.can_force_early_return);
395   JvmtiExport::set_can_support_virtual_threads(_can_support_virtual_threads_count != 0);

396   JvmtiExport::set_should_clean_up_heap_objects(avail.can_generate_breakpoint_events);
397   JvmtiExport::set_can_get_owned_monitor_info(avail.can_get_owned_monitor_info ||
398                                               avail.can_get_owned_monitor_stack_depth_info);
399 }
400 
401 #ifndef PRODUCT
402 
403 void JvmtiManageCapabilities:: print(const jvmtiCapabilities* cap) {
404   log_trace(jvmti)("----- capabilities -----");
405   if (cap->can_tag_objects)
406     log_trace(jvmti)("can_tag_objects");
407   if (cap->can_generate_field_modification_events)
408     log_trace(jvmti)("can_generate_field_modification_events");
409   if (cap->can_generate_field_access_events)
410     log_trace(jvmti)("can_generate_field_access_events");
411   if (cap->can_get_bytecodes)
412     log_trace(jvmti)("can_get_bytecodes");
413   if (cap->can_get_synthetic_attribute)
414     log_trace(jvmti)("can_get_synthetic_attribute");
415   if (cap->can_get_owned_monitor_info)

471   if (cap->can_generate_monitor_events)
472     log_trace(jvmti)("can_generate_monitor_events");
473   if (cap->can_generate_vm_object_alloc_events)
474     log_trace(jvmti)("can_generate_vm_object_alloc_events");
475   if (cap->can_generate_native_method_bind_events)
476     log_trace(jvmti)("can_generate_native_method_bind_events");
477   if (cap->can_generate_garbage_collection_events)
478     log_trace(jvmti)("can_generate_garbage_collection_events");
479   if (cap->can_generate_object_free_events)
480     log_trace(jvmti)("can_generate_object_free_events");
481   if (cap->can_generate_resource_exhaustion_heap_events)
482     log_trace(jvmti)("can_generate_resource_exhaustion_heap_events");
483   if (cap->can_generate_resource_exhaustion_threads_events)
484     log_trace(jvmti)("can_generate_resource_exhaustion_threads_events");
485   if (cap->can_generate_early_vmstart)
486     log_trace(jvmti)("can_generate_early_vmstart");
487   if (cap->can_generate_early_class_hook_events)
488     log_trace(jvmti)("can_generate_early_class_hook_events");
489   if (cap->can_support_virtual_threads)
490     log_trace(jvmti)("can_support_virtual_threads");


491 }
492 
493 #endif

  1 /*
  2  * Copyright (c) 2003, 2026, 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  *

 39   // capabilities which are always potentially available
 40   // but to only one environment
 41 jvmtiCapabilities JvmtiManageCapabilities::always_solo_capabilities;
 42 
 43   // capabilities which are potentially available during OnLoad
 44   // but to only one environment
 45 jvmtiCapabilities JvmtiManageCapabilities::onload_solo_capabilities;
 46 
 47   // remaining capabilities which are always potentially available
 48   // but to only one environment
 49 jvmtiCapabilities JvmtiManageCapabilities::always_solo_remaining_capabilities;
 50 
 51   // remaining capabilities which are potentially available during OnLoad
 52   // but to only one environment
 53 jvmtiCapabilities JvmtiManageCapabilities::onload_solo_remaining_capabilities;
 54 
 55   // all capabilities ever acquired
 56 jvmtiCapabilities JvmtiManageCapabilities::acquired_capabilities;
 57 
 58 int JvmtiManageCapabilities::_can_support_virtual_threads_count = 0;
 59 int JvmtiManageCapabilities::_can_support_value_objects_count = 0;
 60 
 61 Mutex* JvmtiManageCapabilities::_capabilities_lock = nullptr;
 62 
 63 void JvmtiManageCapabilities::initialize() {
 64   _capabilities_lock = new Mutex(Mutex::nosafepoint, "Capabilities_lock");
 65   always_capabilities = init_always_capabilities();
 66   onload_capabilities = init_onload_capabilities();
 67   always_solo_capabilities = init_always_solo_capabilities();
 68   onload_solo_capabilities = init_onload_solo_capabilities();
 69   always_solo_remaining_capabilities = init_always_solo_capabilities();
 70   onload_solo_remaining_capabilities = init_onload_solo_capabilities();
 71   memset(&acquired_capabilities, 0, sizeof(acquired_capabilities));
 72 }
 73 
 74 
 75 // corresponding init functions
 76 jvmtiCapabilities JvmtiManageCapabilities::init_always_capabilities() {
 77   jvmtiCapabilities jc;
 78 
 79   memset(&jc, 0, sizeof(jc));

 87   jc.can_generate_all_class_hook_events = 1;
 88   jc.can_generate_monitor_events = 1;
 89   jc.can_generate_garbage_collection_events = 1;
 90   jc.can_generate_compiled_method_load_events = 1;
 91   jc.can_generate_native_method_bind_events = 1;
 92   jc.can_generate_vm_object_alloc_events = 1;
 93   if (os::is_thread_cpu_time_supported()) {
 94     jc.can_get_current_thread_cpu_time = 1;
 95     jc.can_get_thread_cpu_time = 1;
 96   }
 97   jc.can_redefine_classes = 1;
 98   jc.can_redefine_any_class = 1;
 99   jc.can_retransform_classes = 1;
100   jc.can_retransform_any_class = 1;
101   jc.can_set_native_method_prefix = 1;
102   jc.can_tag_objects = 1;
103   jc.can_generate_object_free_events = 1;
104   jc.can_generate_resource_exhaustion_heap_events = 1;
105   jc.can_generate_resource_exhaustion_threads_events = 1;
106   jc.can_support_virtual_threads = 1;
107   jc.can_support_value_objects = 1;
108   return jc;
109 }
110 
111 jvmtiCapabilities JvmtiManageCapabilities::init_onload_capabilities() {
112   jvmtiCapabilities jc;
113 
114   memset(&jc, 0, sizeof(jc));
115 #ifndef ZERO
116   jc.can_pop_frame = 1;
117   jc.can_force_early_return = 1;
118 #endif // !ZERO
119   jc.can_get_source_debug_extension = 1;
120   jc.can_access_local_variables = 1;
121   jc.can_maintain_original_method_order = 1;
122   jc.can_generate_single_step_events = 1;
123   jc.can_generate_exception_events = 1;
124   jc.can_generate_frame_pop_events = 1;
125   jc.can_generate_method_entry_events = 1;
126   jc.can_generate_method_exit_events = 1;
127   jc.can_get_owned_monitor_info = 1;

262   // add to the set of ever acquired capabilities
263   either(&acquired_capabilities, desired, &acquired_capabilities);
264 
265   // onload capabilities that got added are now permanent - so, also remove from onload
266   both(&onload_capabilities, desired, &temp);
267   either(&always_capabilities, &temp, &always_capabilities);
268   exclude(&onload_capabilities, &temp, &onload_capabilities);
269 
270   // same for solo capabilities (transferred capabilities in the remaining sets handled as part of standard grab - below)
271   both(&onload_solo_capabilities, desired, &temp);
272   either(&always_solo_capabilities, &temp, &always_solo_capabilities);
273   exclude(&onload_solo_capabilities, &temp, &onload_solo_capabilities);
274 
275   // remove solo capabilities that are now taken
276   exclude(&always_solo_remaining_capabilities, desired, &always_solo_remaining_capabilities);
277   exclude(&onload_solo_remaining_capabilities, desired, &onload_solo_remaining_capabilities);
278 
279   if (desired->can_support_virtual_threads != 0 && current->can_support_virtual_threads == 0) {
280     _can_support_virtual_threads_count++;
281   }
282   if (desired->can_support_value_objects != 0 && current->can_support_value_objects == 0) {
283     _can_support_value_objects_count++;
284   }
285 
286   // return the result
287   either(current, desired, result);
288 
289   update();
290 
291   return JVMTI_ERROR_NONE;
292 }
293 
294 
295 void JvmtiManageCapabilities::relinquish_capabilities(const jvmtiCapabilities *current,
296                                                       const jvmtiCapabilities *unwanted,
297                                                       jvmtiCapabilities *result) {
298   CapabilitiesMutexLocker ml;
299 
300   jvmtiCapabilities to_trash;
301   jvmtiCapabilities temp;
302 
303   // can't give up what you don't have
304   both(current, unwanted, &to_trash);
305 
306   // restore solo capabilities but only those that belong
307   either(&always_solo_remaining_capabilities, both(&always_solo_capabilities, &to_trash, &temp),
308          &always_solo_remaining_capabilities);
309   either(&onload_solo_remaining_capabilities, both(&onload_solo_capabilities, &to_trash, &temp),
310          &onload_solo_remaining_capabilities);
311 
312   if (to_trash.can_support_virtual_threads != 0) {
313     assert(current->can_support_virtual_threads != 0, "sanity check");
314     assert(_can_support_virtual_threads_count > 0, "sanity check");
315     _can_support_virtual_threads_count--;
316   }
317   if (to_trash.can_support_value_objects != 0) {
318     assert(current->can_support_value_objects != 0, "sanity check");
319     assert(_can_support_value_objects_count > 0, "sanity check");
320     _can_support_value_objects_count--;
321   }
322 
323   update();
324 
325   // return the result
326   exclude(current, unwanted, result);
327 }
328 
329 
330 void JvmtiManageCapabilities::update() {
331   jvmtiCapabilities avail;
332 
333   // all capabilities
334   either(&always_capabilities, &always_solo_capabilities, &avail);
335 
336   bool interp_events =
337     avail.can_generate_field_access_events ||
338     avail.can_generate_field_modification_events ||
339     avail.can_generate_single_step_events ||
340     avail.can_generate_method_entry_events ||
341     avail.can_generate_method_exit_events;

386   // improve the debugging experience so only set them if the selected
387   // capabilities look like a debugger.
388   JvmtiExport::set_can_access_local_variables(
389     avail.can_access_local_variables ||
390     avail.can_generate_breakpoint_events ||
391     avail.can_generate_frame_pop_events);
392   JvmtiExport::set_can_post_on_exceptions(
393     avail.can_generate_exception_events ||
394     avail.can_generate_frame_pop_events ||
395     avail.can_generate_method_exit_events);
396   JvmtiExport::set_can_post_breakpoint(avail.can_generate_breakpoint_events);
397   JvmtiExport::set_can_post_field_access(avail.can_generate_field_access_events);
398   JvmtiExport::set_can_post_field_modification(avail.can_generate_field_modification_events);
399   JvmtiExport::set_can_post_method_entry(avail.can_generate_method_entry_events);
400   JvmtiExport::set_can_post_method_exit(avail.can_generate_method_exit_events ||
401                                         avail.can_generate_frame_pop_events);
402   JvmtiExport::set_can_post_frame_pop(avail.can_generate_frame_pop_events);
403   JvmtiExport::set_can_pop_frame(avail.can_pop_frame);
404   JvmtiExport::set_can_force_early_return(avail.can_force_early_return);
405   JvmtiExport::set_can_support_virtual_threads(_can_support_virtual_threads_count != 0);
406   JvmtiExport::set_can_support_value_objects(_can_support_value_objects_count != 0);
407   JvmtiExport::set_should_clean_up_heap_objects(avail.can_generate_breakpoint_events);
408   JvmtiExport::set_can_get_owned_monitor_info(avail.can_get_owned_monitor_info ||
409                                               avail.can_get_owned_monitor_stack_depth_info);
410 }
411 
412 #ifndef PRODUCT
413 
414 void JvmtiManageCapabilities:: print(const jvmtiCapabilities* cap) {
415   log_trace(jvmti)("----- capabilities -----");
416   if (cap->can_tag_objects)
417     log_trace(jvmti)("can_tag_objects");
418   if (cap->can_generate_field_modification_events)
419     log_trace(jvmti)("can_generate_field_modification_events");
420   if (cap->can_generate_field_access_events)
421     log_trace(jvmti)("can_generate_field_access_events");
422   if (cap->can_get_bytecodes)
423     log_trace(jvmti)("can_get_bytecodes");
424   if (cap->can_get_synthetic_attribute)
425     log_trace(jvmti)("can_get_synthetic_attribute");
426   if (cap->can_get_owned_monitor_info)

482   if (cap->can_generate_monitor_events)
483     log_trace(jvmti)("can_generate_monitor_events");
484   if (cap->can_generate_vm_object_alloc_events)
485     log_trace(jvmti)("can_generate_vm_object_alloc_events");
486   if (cap->can_generate_native_method_bind_events)
487     log_trace(jvmti)("can_generate_native_method_bind_events");
488   if (cap->can_generate_garbage_collection_events)
489     log_trace(jvmti)("can_generate_garbage_collection_events");
490   if (cap->can_generate_object_free_events)
491     log_trace(jvmti)("can_generate_object_free_events");
492   if (cap->can_generate_resource_exhaustion_heap_events)
493     log_trace(jvmti)("can_generate_resource_exhaustion_heap_events");
494   if (cap->can_generate_resource_exhaustion_threads_events)
495     log_trace(jvmti)("can_generate_resource_exhaustion_threads_events");
496   if (cap->can_generate_early_vmstart)
497     log_trace(jvmti)("can_generate_early_vmstart");
498   if (cap->can_generate_early_class_hook_events)
499     log_trace(jvmti)("can_generate_early_class_hook_events");
500   if (cap->can_support_virtual_threads)
501     log_trace(jvmti)("can_support_virtual_threads");
502   if (cap->can_support_value_objects)
503     log_trace(jvmti)("can_support_value_objects");
504 }
505 
506 #endif
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