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 *
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
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));
79 jc.can_get_bytecodes = 1;
80 jc.can_signal_thread = 1;
81 jc.can_get_source_file_name = 1;
82 jc.can_get_line_numbers = 1;
83 jc.can_get_synthetic_attribute = 1;
84 jc.can_get_monitor_info = 1;
85 jc.can_get_constant_pool = 1;
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;
126 jc.can_get_owned_monitor_stack_depth_info = 1;
127 jc.can_get_current_contended_monitor = 1;
128 jc.can_generate_early_vmstart = 1;
129 jc.can_generate_early_class_hook_events = 1;
130 return jc;
131 }
132
133
134 jvmtiCapabilities JvmtiManageCapabilities::init_always_solo_capabilities() {
135 jvmtiCapabilities jc;
136
137 memset(&jc, 0, sizeof(jc));
138 jc.can_suspend = 1;
139 jc.can_generate_sampled_object_alloc_events = 1;
140 return jc;
141 }
142
143
144 jvmtiCapabilities JvmtiManageCapabilities::init_onload_solo_capabilities() {
145 jvmtiCapabilities jc;
146
147 memset(&jc, 0, sizeof(jc));
148 jc.can_generate_field_modification_events = 1;
149 jc.can_generate_field_access_events = 1;
150 jc.can_generate_breakpoint_events = 1;
151 return jc;
152 }
153
154
155 jvmtiCapabilities *JvmtiManageCapabilities::either(const jvmtiCapabilities *a, const jvmtiCapabilities *b,
156 jvmtiCapabilities *result) {
157 char *ap = (char *)a;
158 char *bp = (char *)b;
159 char *resultp = (char *)result;
160
161 for (int i = 0; i < CAPA_SIZE; ++i) {
162 *resultp++ = *ap++ | *bp++;
163 }
164
165 return result;
166 }
167
168
169 jvmtiCapabilities *JvmtiManageCapabilities::both(const jvmtiCapabilities *a, const jvmtiCapabilities *b,
170 jvmtiCapabilities *result) {
171 char *ap = (char *)a;
172 char *bp = (char *)b;
173 char *resultp = (char *)result;
174
175 for (int i = 0; i < CAPA_SIZE; ++i) {
176 *resultp++ = *ap++ & *bp++;
177 }
178
179 return result;
180 }
181
182
183 jvmtiCapabilities *JvmtiManageCapabilities::exclude(const jvmtiCapabilities *a, const jvmtiCapabilities *b,
184 jvmtiCapabilities *result) {
185 char *ap = (char *)a;
186 char *bp = (char *)b;
187 char *resultp = (char *)result;
188
189 for (int i = 0; i < CAPA_SIZE; ++i) {
190 *resultp++ = *ap++ & (char)~*bp++;
191 }
192
193 return result;
194 }
195
196
197 bool JvmtiManageCapabilities::has_some(const jvmtiCapabilities *a) {
198 char *ap = (char *)a;
199
200 for (int i = 0; i < CAPA_SIZE; ++i) {
201 if (*ap++ != 0) {
202 return true;
203 }
204 }
205
206 return false;
207 }
208
209
210 void JvmtiManageCapabilities::copy_capabilities(const jvmtiCapabilities *from, jvmtiCapabilities *to) {
211 char *ap = (char *)from;
212 char *resultp = (char *)to;
213
214 for (int i = 0; i < CAPA_SIZE; ++i) {
215 *resultp++ = *ap++;
216 }
217 }
218
219
220
221 void JvmtiManageCapabilities::get_potential_capabilities_nolock(const jvmtiCapabilities *current,
222 const jvmtiCapabilities *prohibited,
223 jvmtiCapabilities *result) {
224 // exclude prohibited capabilities, must be before adding current
225 exclude(&always_capabilities, prohibited, result);
226
227 // must include current since it may possess solo capabilities and now prohibited
228 either(result, current, result);
229
230 // add other remaining
231 either(result, &always_solo_remaining_capabilities, result);
232
233 // if this is during OnLoad more capabilities are available
234 if (JvmtiEnv::get_phase() == JVMTI_PHASE_ONLOAD) {
235 either(result, &onload_capabilities, result);
236 either(result, &onload_solo_remaining_capabilities, result);
237 }
238 }
239
240 void JvmtiManageCapabilities::get_potential_capabilities(const jvmtiCapabilities* current,
241 const jvmtiCapabilities* prohibited,
242 jvmtiCapabilities* result) {
243 CapabilitiesMutexLocker ml;
244 get_potential_capabilities_nolock(current, prohibited, result);
245 }
246
247 jvmtiError JvmtiManageCapabilities::add_capabilities(const jvmtiCapabilities *current,
248 const jvmtiCapabilities *prohibited,
249 const jvmtiCapabilities *desired,
250 jvmtiCapabilities *result) {
251 CapabilitiesMutexLocker ml;
252
253 // check that the capabilities being added are potential capabilities
254 jvmtiCapabilities temp;
255 get_potential_capabilities_nolock(current, prohibited, &temp);
256 if (has_some(exclude(desired, &temp, &temp))) {
257 return JVMTI_ERROR_NOT_AVAILABLE;
258 }
259
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;
332 #ifdef ZERO
333 bool enter_all_methods =
334 interp_events ||
335 avail.can_generate_breakpoint_events;
336 if (enter_all_methods) {
337 // Disable these when tracking the bytecodes
338 UseFastEmptyMethods = false;
339 UseFastAccessorMethods = false;
340 }
341 #endif // ZERO
342
343 if (avail.can_generate_breakpoint_events
344 || avail.can_generate_field_access_events
345 || avail.can_generate_field_modification_events)
346 {
347 RewriteFrequentPairs = false;
348 #ifdef ZERO
349 // The BytecodeInterpreter is specialized only with RewriteBytecodes
350 // for simplicity. If we want to disable RewriteFrequentPairs, we
351 // need to disable RewriteBytecodes as well.
352 RewriteBytecodes = false;
353 #endif
354 }
355
356 // If can_redefine_classes is enabled in the onload phase then we know that the
357 // dependency information recorded by the compiler is complete.
358 if ((avail.can_redefine_classes || avail.can_retransform_classes) &&
359 JvmtiEnv::get_phase() == JVMTI_PHASE_ONLOAD) {
360 JvmtiExport::set_all_dependencies_are_recorded(true);
361 }
362
363 JvmtiExport::set_can_get_source_debug_extension(avail.can_get_source_debug_extension);
364 JvmtiExport::set_can_maintain_original_method_order(avail.can_maintain_original_method_order);
365 JvmtiExport::set_can_post_interpreter_events(interp_events);
366 JvmtiExport::set_can_hotswap_or_post_breakpoint(
367 avail.can_generate_breakpoint_events ||
368 avail.can_redefine_classes ||
369 avail.can_retransform_classes);
370 JvmtiExport::set_can_modify_any_class(
371 avail.can_generate_breakpoint_events ||
372 avail.can_generate_all_class_hook_events);
373 JvmtiExport::set_can_walk_any_space(
374 avail.can_tag_objects); // disable sharing in onload phase
375 // This controls whether the compilers keep extra locals live to
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)
416 log_trace(jvmti)("can_get_owned_monitor_info");
417 if (cap->can_get_current_contended_monitor)
418 log_trace(jvmti)("can_get_current_contended_monitor");
419 if (cap->can_get_monitor_info)
420 log_trace(jvmti)("can_get_monitor_info");
421 if (cap->can_get_constant_pool)
422 log_trace(jvmti)("can_get_constant_pool");
423 if (cap->can_pop_frame)
424 log_trace(jvmti)("can_pop_frame");
425 if (cap->can_force_early_return)
426 log_trace(jvmti)("can_force_early_return");
427 if (cap->can_redefine_classes)
428 log_trace(jvmti)("can_redefine_classes");
429 if (cap->can_retransform_classes)
430 log_trace(jvmti)("can_retransform_classes");
431 if (cap->can_signal_thread)
432 log_trace(jvmti)("can_signal_thread");
433 if (cap->can_get_source_file_name)
434 log_trace(jvmti)("can_get_source_file_name");
435 if (cap->can_get_line_numbers)
436 log_trace(jvmti)("can_get_line_numbers");
437 if (cap->can_get_source_debug_extension)
438 log_trace(jvmti)("can_get_source_debug_extension");
439 if (cap->can_access_local_variables)
440 log_trace(jvmti)("can_access_local_variables");
441 if (cap->can_maintain_original_method_order)
442 log_trace(jvmti)("can_maintain_original_method_order");
443 if (cap->can_generate_single_step_events)
444 log_trace(jvmti)("can_generate_single_step_events");
445 if (cap->can_generate_exception_events)
446 log_trace(jvmti)("can_generate_exception_events");
447 if (cap->can_generate_frame_pop_events)
448 log_trace(jvmti)("can_generate_frame_pop_events");
449 if (cap->can_generate_breakpoint_events)
450 log_trace(jvmti)("can_generate_breakpoint_events");
451 if (cap->can_generate_sampled_object_alloc_events)
452 log_trace(jvmti)("can_generate_sampled_object_alloc_events");
453 if (cap->can_suspend)
454 log_trace(jvmti)("can_suspend");
455 if (cap->can_redefine_any_class )
456 log_trace(jvmti)("can_redefine_any_class");
457 if (cap->can_retransform_any_class )
458 log_trace(jvmti)("can_retransform_any_class");
459 if (cap->can_get_current_thread_cpu_time)
460 log_trace(jvmti)("can_get_current_thread_cpu_time");
461 if (cap->can_get_thread_cpu_time)
462 log_trace(jvmti)("can_get_thread_cpu_time");
463 if (cap->can_generate_method_entry_events)
464 log_trace(jvmti)("can_generate_method_entry_events");
465 if (cap->can_generate_method_exit_events)
466 log_trace(jvmti)("can_generate_method_exit_events");
467 if (cap->can_generate_all_class_hook_events)
468 log_trace(jvmti)("can_generate_all_class_hook_events");
469 if (cap->can_generate_compiled_method_load_events)
470 log_trace(jvmti)("can_generate_compiled_method_load_events");
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