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 *
23 */
24
25 #include "jvmtifiles/jvmtiEnv.hpp"
26 #include "logging/log.hpp"
27 #include "prims/jvmtiExport.hpp"
28 #include "prims/jvmtiManageCapabilities.hpp"
29 #include "runtime/mutexLocker.hpp"
30
31 static const jint CAPA_SIZE = (JVMTI_INTERNAL_CAPABILITY_COUNT + 7) / 8;
32
33 // capabilities which are always potentially available
34 jvmtiCapabilities JvmtiManageCapabilities::always_capabilities;
35
36 // capabilities which are potentially available during OnLoad
37 jvmtiCapabilities JvmtiManageCapabilities::onload_capabilities;
38
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));
80 jc.can_get_bytecodes = 1;
81 jc.can_signal_thread = 1;
82 jc.can_get_source_file_name = 1;
83 jc.can_get_line_numbers = 1;
84 jc.can_get_synthetic_attribute = 1;
85 jc.can_get_monitor_info = 1;
86 jc.can_get_constant_pool = 1;
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;
128 jc.can_get_owned_monitor_stack_depth_info = 1;
129 jc.can_get_current_contended_monitor = 1;
130 jc.can_generate_early_vmstart = 1;
131 jc.can_generate_early_class_hook_events = 1;
132 return jc;
133 }
134
135
136 jvmtiCapabilities JvmtiManageCapabilities::init_always_solo_capabilities() {
137 jvmtiCapabilities jc;
138
139 memset(&jc, 0, sizeof(jc));
140 jc.can_suspend = 1;
141 jc.can_generate_sampled_object_alloc_events = 1;
142 return jc;
143 }
144
145
146 jvmtiCapabilities JvmtiManageCapabilities::init_onload_solo_capabilities() {
147 jvmtiCapabilities jc;
148
149 memset(&jc, 0, sizeof(jc));
150 jc.can_generate_field_modification_events = 1;
151 jc.can_generate_field_access_events = 1;
152 jc.can_generate_breakpoint_events = 1;
153 return jc;
154 }
155
156
157 jvmtiCapabilities *JvmtiManageCapabilities::either(const jvmtiCapabilities *a, const jvmtiCapabilities *b,
158 jvmtiCapabilities *result) {
159 char *ap = (char *)a;
160 char *bp = (char *)b;
161 char *resultp = (char *)result;
162
163 for (int i = 0; i < CAPA_SIZE; ++i) {
164 *resultp++ = *ap++ | *bp++;
165 }
166
167 return result;
168 }
169
170
171 jvmtiCapabilities *JvmtiManageCapabilities::both(const jvmtiCapabilities *a, const jvmtiCapabilities *b,
172 jvmtiCapabilities *result) {
173 char *ap = (char *)a;
174 char *bp = (char *)b;
175 char *resultp = (char *)result;
176
177 for (int i = 0; i < CAPA_SIZE; ++i) {
178 *resultp++ = *ap++ & *bp++;
179 }
180
181 return result;
182 }
183
184
185 jvmtiCapabilities *JvmtiManageCapabilities::exclude(const jvmtiCapabilities *a, const jvmtiCapabilities *b,
186 jvmtiCapabilities *result) {
187 char *ap = (char *)a;
188 char *bp = (char *)b;
189 char *resultp = (char *)result;
190
191 for (int i = 0; i < CAPA_SIZE; ++i) {
192 *resultp++ = *ap++ & (char)~*bp++;
193 }
194
195 return result;
196 }
197
198
199 bool JvmtiManageCapabilities::has_some(const jvmtiCapabilities *a) {
200 char *ap = (char *)a;
201
202 for (int i = 0; i < CAPA_SIZE; ++i) {
203 if (*ap++ != 0) {
204 return true;
205 }
206 }
207
208 return false;
209 }
210
211
212 void JvmtiManageCapabilities::copy_capabilities(const jvmtiCapabilities *from, jvmtiCapabilities *to) {
213 char *ap = (char *)from;
214 char *resultp = (char *)to;
215
216 for (int i = 0; i < CAPA_SIZE; ++i) {
217 *resultp++ = *ap++;
218 }
219 }
220
221
222
223 void JvmtiManageCapabilities::get_potential_capabilities_nolock(const jvmtiCapabilities *current,
224 const jvmtiCapabilities *prohibited,
225 jvmtiCapabilities *result) {
226 // exclude prohibited capabilities, must be before adding current
227 exclude(&always_capabilities, prohibited, result);
228
229 // must include current since it may possess solo capabilities and now prohibited
230 either(result, current, result);
231
232 // add other remaining
233 either(result, &always_solo_remaining_capabilities, result);
234
235 // if this is during OnLoad more capabilities are available
236 if (JvmtiEnv::get_phase() == JVMTI_PHASE_ONLOAD) {
237 either(result, &onload_capabilities, result);
238 either(result, &onload_solo_remaining_capabilities, result);
239 }
240 }
241
242 void JvmtiManageCapabilities::get_potential_capabilities(const jvmtiCapabilities* current,
243 const jvmtiCapabilities* prohibited,
244 jvmtiCapabilities* result) {
245 CapabilitiesMutexLocker ml;
246 get_potential_capabilities_nolock(current, prohibited, result);
247 }
248
249 jvmtiError JvmtiManageCapabilities::add_capabilities(const jvmtiCapabilities *current,
250 const jvmtiCapabilities *prohibited,
251 const jvmtiCapabilities *desired,
252 jvmtiCapabilities *result) {
253 CapabilitiesMutexLocker ml;
254
255 // check that the capabilities being added are potential capabilities
256 jvmtiCapabilities temp;
257 get_potential_capabilities_nolock(current, prohibited, &temp);
258 if (has_some(exclude(desired, &temp, &temp))) {
259 return JVMTI_ERROR_NOT_AVAILABLE;
260 }
261
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;
342 #ifdef ZERO
343 bool enter_all_methods =
344 interp_events ||
345 avail.can_generate_breakpoint_events;
346 if (enter_all_methods) {
347 // Disable these when tracking the bytecodes
348 UseFastEmptyMethods = false;
349 UseFastAccessorMethods = false;
350 }
351 #endif // ZERO
352
353 if (avail.can_generate_breakpoint_events
354 || avail.can_generate_field_access_events
355 || avail.can_generate_field_modification_events)
356 {
357 RewriteFrequentPairs = false;
358 #ifdef ZERO
359 // The BytecodeInterpreter is specialized only with RewriteBytecodes
360 // for simplicity. If we want to disable RewriteFrequentPairs, we
361 // need to disable RewriteBytecodes as well.
362 RewriteBytecodes = false;
363 #endif
364 }
365
366 // If can_redefine_classes is enabled in the onload phase then we know that the
367 // dependency information recorded by the compiler is complete.
368 if ((avail.can_redefine_classes || avail.can_retransform_classes) &&
369 JvmtiEnv::get_phase() == JVMTI_PHASE_ONLOAD) {
370 JvmtiExport::set_all_dependencies_are_recorded(true);
371 }
372
373 JvmtiExport::set_can_get_source_debug_extension(avail.can_get_source_debug_extension);
374 JvmtiExport::set_can_maintain_original_method_order(avail.can_maintain_original_method_order);
375 JvmtiExport::set_can_post_interpreter_events(interp_events);
376 JvmtiExport::set_can_hotswap_or_post_breakpoint(
377 avail.can_generate_breakpoint_events ||
378 avail.can_redefine_classes ||
379 avail.can_retransform_classes);
380 JvmtiExport::set_can_modify_any_class(
381 avail.can_generate_breakpoint_events ||
382 avail.can_generate_all_class_hook_events);
383 JvmtiExport::set_can_walk_any_space(
384 avail.can_tag_objects); // disable sharing in onload phase
385 // This controls whether the compilers keep extra locals live to
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)
427 log_trace(jvmti)("can_get_owned_monitor_info");
428 if (cap->can_get_current_contended_monitor)
429 log_trace(jvmti)("can_get_current_contended_monitor");
430 if (cap->can_get_monitor_info)
431 log_trace(jvmti)("can_get_monitor_info");
432 if (cap->can_get_constant_pool)
433 log_trace(jvmti)("can_get_constant_pool");
434 if (cap->can_pop_frame)
435 log_trace(jvmti)("can_pop_frame");
436 if (cap->can_force_early_return)
437 log_trace(jvmti)("can_force_early_return");
438 if (cap->can_redefine_classes)
439 log_trace(jvmti)("can_redefine_classes");
440 if (cap->can_retransform_classes)
441 log_trace(jvmti)("can_retransform_classes");
442 if (cap->can_signal_thread)
443 log_trace(jvmti)("can_signal_thread");
444 if (cap->can_get_source_file_name)
445 log_trace(jvmti)("can_get_source_file_name");
446 if (cap->can_get_line_numbers)
447 log_trace(jvmti)("can_get_line_numbers");
448 if (cap->can_get_source_debug_extension)
449 log_trace(jvmti)("can_get_source_debug_extension");
450 if (cap->can_access_local_variables)
451 log_trace(jvmti)("can_access_local_variables");
452 if (cap->can_maintain_original_method_order)
453 log_trace(jvmti)("can_maintain_original_method_order");
454 if (cap->can_generate_single_step_events)
455 log_trace(jvmti)("can_generate_single_step_events");
456 if (cap->can_generate_exception_events)
457 log_trace(jvmti)("can_generate_exception_events");
458 if (cap->can_generate_frame_pop_events)
459 log_trace(jvmti)("can_generate_frame_pop_events");
460 if (cap->can_generate_breakpoint_events)
461 log_trace(jvmti)("can_generate_breakpoint_events");
462 if (cap->can_generate_sampled_object_alloc_events)
463 log_trace(jvmti)("can_generate_sampled_object_alloc_events");
464 if (cap->can_suspend)
465 log_trace(jvmti)("can_suspend");
466 if (cap->can_redefine_any_class )
467 log_trace(jvmti)("can_redefine_any_class");
468 if (cap->can_retransform_any_class )
469 log_trace(jvmti)("can_retransform_any_class");
470 if (cap->can_get_current_thread_cpu_time)
471 log_trace(jvmti)("can_get_current_thread_cpu_time");
472 if (cap->can_get_thread_cpu_time)
473 log_trace(jvmti)("can_get_thread_cpu_time");
474 if (cap->can_generate_method_entry_events)
475 log_trace(jvmti)("can_generate_method_entry_events");
476 if (cap->can_generate_method_exit_events)
477 log_trace(jvmti)("can_generate_method_exit_events");
478 if (cap->can_generate_all_class_hook_events)
479 log_trace(jvmti)("can_generate_all_class_hook_events");
480 if (cap->can_generate_compiled_method_load_events)
481 log_trace(jvmti)("can_generate_compiled_method_load_events");
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