1 /*
2 * Copyright (c) 2003, 2018, 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/classLoaderData.inline.hpp"
27 #include "classfile/dictionary.inline.hpp"
28 #include "classfile/protectionDomainCache.hpp"
29 #include "classfile/systemDictionary.hpp"
30 #include "classfile/systemDictionaryShared.hpp"
31 #include "logging/log.hpp"
32 #include "logging/logStream.hpp"
33 #include "memory/iterator.hpp"
34 #include "memory/metaspaceClosure.hpp"
35 #include "memory/resourceArea.hpp"
36 #include "oops/oop.inline.hpp"
37 #include "runtime/atomic.hpp"
38 #include "runtime/orderAccess.hpp"
39 #include "runtime/safepointVerifiers.hpp"
40 #include "utilities/hashtable.inline.hpp"
41
42 // Optimization: if any dictionary needs resizing, we set this flag,
43 // so that we dont't have to walk all dictionaries to check if any actually
44 // needs resizing, which is costly to do at Safepoint.
45 bool Dictionary::_some_dictionary_needs_resizing = false;
46
47 size_t Dictionary::entry_size() {
48 if (DumpSharedSpaces) {
49 return SystemDictionaryShared::dictionary_entry_size();
50 } else {
51 return sizeof(DictionaryEntry);
52 }
53 }
54
55 Dictionary::Dictionary(ClassLoaderData* loader_data, int table_size, bool resizable)
56 : Hashtable<InstanceKlass*, mtClass>(table_size, (int)entry_size()),
57 _resizable(resizable), _needs_resizing(false), _loader_data(loader_data) {
58 };
59
60
61 Dictionary::Dictionary(ClassLoaderData* loader_data,
62 int table_size, HashtableBucket<mtClass>* t,
63 int number_of_entries, bool resizable)
64 : Hashtable<InstanceKlass*, mtClass>(table_size, (int)entry_size(), t, number_of_entries),
65 _resizable(resizable), _needs_resizing(false), _loader_data(loader_data) {
66 };
67
68 Dictionary::~Dictionary() {
69 DictionaryEntry* probe = NULL;
70 for (int index = 0; index < table_size(); index++) {
71 for (DictionaryEntry** p = bucket_addr(index); *p != NULL; ) {
72 probe = *p;
73 *p = probe->next();
74 free_entry(probe);
75 }
76 }
77 assert(number_of_entries() == 0, "should have removed all entries");
78 assert(new_entry_free_list() == NULL, "entry present on Dictionary's free list");
79 free_buckets();
80 }
81
82 DictionaryEntry* Dictionary::new_entry(unsigned int hash, InstanceKlass* klass) {
83 DictionaryEntry* entry = (DictionaryEntry*)Hashtable<InstanceKlass*, mtClass>::allocate_new_entry(hash, klass);
84 entry->set_pd_set(NULL);
85 assert(klass->is_instance_klass(), "Must be");
86 if (DumpSharedSpaces) {
87 SystemDictionaryShared::init_shared_dictionary_entry(klass, entry);
88 }
89 return entry;
90 }
91
92
93 void Dictionary::free_entry(DictionaryEntry* entry) {
94 // avoid recursion when deleting linked list
95 // pd_set is accessed during a safepoint.
96 while (entry->pd_set() != NULL) {
97 ProtectionDomainEntry* to_delete = entry->pd_set();
98 entry->set_pd_set(to_delete->next());
99 delete to_delete;
100 }
101 // Unlink from the Hashtable prior to freeing
102 unlink_entry(entry);
103 FREE_C_HEAP_ARRAY(char, entry);
104 }
105
106 const int _resize_load_trigger = 5; // load factor that will trigger the resize
107 const double _resize_factor = 2.0; // by how much we will resize using current number of entries
108 const int _resize_max_size = 40423; // the max dictionary size allowed
109 const int _primelist[] = {107, 1009, 2017, 4049, 5051, 10103, 20201, _resize_max_size};
110 const int _prime_array_size = sizeof(_primelist)/sizeof(int);
111
112 // Calculate next "good" dictionary size based on requested count
113 static int calculate_dictionary_size(int requested) {
114 int newsize = _primelist[0];
115 int index = 0;
116 for (newsize = _primelist[index]; index < (_prime_array_size - 1);
117 newsize = _primelist[++index]) {
118 if (requested <= newsize) {
119 break;
120 }
121 }
122 return newsize;
123 }
124
125 bool Dictionary::does_any_dictionary_needs_resizing() {
126 return Dictionary::_some_dictionary_needs_resizing;
127 }
128
129 void Dictionary::check_if_needs_resize() {
130 if (_resizable == true) {
131 if (number_of_entries() > (_resize_load_trigger*table_size())) {
132 _needs_resizing = true;
133 Dictionary::_some_dictionary_needs_resizing = true;
134 }
135 }
136 }
137
138 bool Dictionary::resize_if_needed() {
139 int desired_size = 0;
140 if (_needs_resizing == true) {
141 desired_size = calculate_dictionary_size((int)(_resize_factor*number_of_entries()));
142 if (desired_size >= _resize_max_size) {
143 desired_size = _resize_max_size;
144 // We have reached the limit, turn resizing off
145 _resizable = false;
146 }
147 if ((desired_size != 0) && (desired_size != table_size())) {
148 if (!resize(desired_size)) {
149 // Something went wrong, turn resizing off
150 _resizable = false;
151 }
152 }
153 }
154
155 _needs_resizing = false;
156 Dictionary::_some_dictionary_needs_resizing = false;
157
158 return (desired_size != 0);
159 }
160
161 bool DictionaryEntry::contains_protection_domain(oop protection_domain) const {
162 #ifdef ASSERT
163 if (oopDesc::equals(protection_domain, instance_klass()->protection_domain())) {
164 // Ensure this doesn't show up in the pd_set (invariant)
165 bool in_pd_set = false;
166 for (ProtectionDomainEntry* current = pd_set_acquire();
167 current != NULL;
168 current = current->next()) {
169 if (oopDesc::equals(current->object_no_keepalive(), protection_domain)) {
170 in_pd_set = true;
171 break;
172 }
173 }
174 if (in_pd_set) {
175 assert(false, "A klass's protection domain should not show up "
176 "in its sys. dict. PD set");
177 }
178 }
179 #endif /* ASSERT */
180
181 if (oopDesc::equals(protection_domain, instance_klass()->protection_domain())) {
182 // Succeeds trivially
183 return true;
184 }
185
186 for (ProtectionDomainEntry* current = pd_set_acquire();
187 current != NULL;
188 current = current->next()) {
189 if (oopDesc::equals(current->object_no_keepalive(), protection_domain)) return true;
190 }
191 return false;
192 }
193
194
195 void DictionaryEntry::add_protection_domain(Dictionary* dict, Handle protection_domain) {
196 assert_locked_or_safepoint(SystemDictionary_lock);
197 if (!contains_protection_domain(protection_domain())) {
198 ProtectionDomainCacheEntry* entry = SystemDictionary::cache_get(protection_domain);
199 ProtectionDomainEntry* new_head =
200 new ProtectionDomainEntry(entry, pd_set());
201 // Warning: Preserve store ordering. The SystemDictionary is read
202 // without locks. The new ProtectionDomainEntry must be
203 // complete before other threads can be allowed to see it
204 // via a store to _pd_set.
205 release_set_pd_set(new_head);
206 }
207 LogTarget(Trace, protectiondomain) lt;
208 if (lt.is_enabled()) {
209 LogStream ls(lt);
210 print_count(&ls);
211 }
212 }
213
214 // During class loading we may have cached a protection domain that has
215 // since been unreferenced, so this entry should be cleared.
216 void Dictionary::clean_cached_protection_domains(DictionaryEntry* probe) {
217 assert_locked_or_safepoint(SystemDictionary_lock);
218
219 ProtectionDomainEntry* current = probe->pd_set();
220 ProtectionDomainEntry* prev = NULL;
221 while (current != NULL) {
222 if (current->object_no_keepalive() == NULL) {
223 LogTarget(Debug, protectiondomain) lt;
224 if (lt.is_enabled()) {
225 ResourceMark rm;
226 // Print out trace information
227 LogStream ls(lt);
228 ls.print_cr("PD in set is not alive:");
229 ls.print("class loader: "); loader_data()->class_loader()->print_value_on(&ls);
230 ls.print(" loading: "); probe->instance_klass()->print_value_on(&ls);
231 ls.cr();
232 }
233 if (probe->pd_set() == current) {
234 probe->set_pd_set(current->next());
235 } else {
236 assert(prev != NULL, "should be set by alive entry");
237 prev->set_next(current->next());
238 }
239 ProtectionDomainEntry* to_delete = current;
240 current = current->next();
241 delete to_delete;
242 } else {
243 prev = current;
244 current = current->next();
245 }
246 }
247 }
248
249
250 void Dictionary::do_unloading() {
251 MutexLockerEx m(SystemDictionary_lock);
252 assert(UseZGC || SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
253
254 // The NULL class loader doesn't initiate loading classes from other class loaders
255 if (loader_data() == ClassLoaderData::the_null_class_loader_data()) {
256 return;
257 }
258
259 // Remove unloaded entries and classes from this dictionary
260 DictionaryEntry* probe = NULL;
261 for (int index = 0; index < table_size(); index++) {
262 for (DictionaryEntry** p = bucket_addr(index); *p != NULL; ) {
263 probe = *p;
264 InstanceKlass* ik = probe->instance_klass();
265 ClassLoaderData* k_def_class_loader_data = ik->class_loader_data();
266
267 // If the klass that this loader initiated is dead,
268 // (determined by checking the defining class loader)
269 // remove this entry.
270 if (k_def_class_loader_data->is_unloading()) {
271 assert(k_def_class_loader_data != loader_data(),
272 "cannot have live defining loader and unreachable klass");
273 *p = probe->next();
274 free_entry(probe);
275 continue;
276 }
277 // Clean pd_set
278 clean_cached_protection_domains(probe);
279 p = probe->next_addr();
280 }
281 }
282 }
283
284 void Dictionary::remove_classes_in_error_state() {
285 assert(DumpSharedSpaces, "supported only when dumping");
286 DictionaryEntry* probe = NULL;
287 for (int index = 0; index < table_size(); index++) {
288 for (DictionaryEntry** p = bucket_addr(index); *p != NULL; ) {
289 probe = *p;
290 InstanceKlass* ik = probe->instance_klass();
291 if (ik->is_in_error_state()) { // purge this entry
292 *p = probe->next();
293 free_entry(probe);
294 ResourceMark rm;
295 tty->print_cr("Preload Warning: Removed error class: %s", ik->external_name());
296 continue;
297 }
298
299 p = probe->next_addr();
300 }
301 }
302 }
303
304 // Just the classes from defining class loaders
305 void Dictionary::classes_do(void f(InstanceKlass*)) {
306 for (int index = 0; index < table_size(); index++) {
307 for (DictionaryEntry* probe = bucket(index);
308 probe != NULL;
309 probe = probe->next()) {
310 InstanceKlass* k = probe->instance_klass();
311 if (loader_data() == k->class_loader_data()) {
312 f(k);
313 }
314 }
315 }
316 }
317
318 // Added for initialize_itable_for_klass to handle exceptions
319 // Just the classes from defining class loaders
320 void Dictionary::classes_do(void f(InstanceKlass*, TRAPS), TRAPS) {
321 for (int index = 0; index < table_size(); index++) {
322 for (DictionaryEntry* probe = bucket(index);
323 probe != NULL;
324 probe = probe->next()) {
325 InstanceKlass* k = probe->instance_klass();
326 if (loader_data() == k->class_loader_data()) {
327 f(k, CHECK);
328 }
329 }
330 }
331 }
332
333 // All classes, and their class loaders, including initiating class loaders
334 void Dictionary::all_entries_do(void f(InstanceKlass*, ClassLoaderData*)) {
335 for (int index = 0; index < table_size(); index++) {
336 for (DictionaryEntry* probe = bucket(index);
337 probe != NULL;
338 probe = probe->next()) {
339 InstanceKlass* k = probe->instance_klass();
340 f(k, loader_data());
341 }
342 }
343 }
344
345 // Used to scan and relocate the classes during CDS archive dump.
346 void Dictionary::classes_do(MetaspaceClosure* it) {
347 assert(DumpSharedSpaces, "dump-time only");
348 for (int index = 0; index < table_size(); index++) {
349 for (DictionaryEntry* probe = bucket(index);
350 probe != NULL;
351 probe = probe->next()) {
352 it->push(probe->klass_addr());
353 ((SharedDictionaryEntry*)probe)->metaspace_pointers_do(it);
354 }
355 }
356 }
357
358
359
360 // Add a loaded class to the dictionary.
361 // Readers of the SystemDictionary aren't always locked, so _buckets
362 // is volatile. The store of the next field in the constructor is
363 // also cast to volatile; we do this to ensure store order is maintained
364 // by the compilers.
365
366 void Dictionary::add_klass(unsigned int hash, Symbol* class_name,
367 InstanceKlass* obj) {
368 assert_locked_or_safepoint(SystemDictionary_lock);
369 assert(obj != NULL, "adding NULL obj");
370 assert(obj->name() == class_name, "sanity check on name");
371
372 DictionaryEntry* entry = new_entry(hash, obj);
373 int index = hash_to_index(hash);
374 add_entry(index, entry);
375 check_if_needs_resize();
376 }
377
378
379 // This routine does not lock the dictionary.
380 //
381 // Since readers don't hold a lock, we must make sure that system
382 // dictionary entries are only removed at a safepoint (when only one
383 // thread is running), and are added to in a safe way (all links must
384 // be updated in an MT-safe manner).
385 //
386 // Callers should be aware that an entry could be added just after
387 // _buckets[index] is read here, so the caller will not see the new entry.
388 DictionaryEntry* Dictionary::get_entry(int index, unsigned int hash,
389 Symbol* class_name) {
390 for (DictionaryEntry* entry = bucket(index);
391 entry != NULL;
392 entry = entry->next()) {
393 if (entry->hash() == hash && entry->equals(class_name)) {
394 if (!DumpSharedSpaces || SystemDictionaryShared::is_builtin(entry)) {
395 return entry;
396 }
397 }
398 }
399 return NULL;
400 }
401
402
403 InstanceKlass* Dictionary::find(unsigned int hash, Symbol* name,
404 Handle protection_domain) {
405 NoSafepointVerifier nsv;
406
407 int index = hash_to_index(hash);
408 DictionaryEntry* entry = get_entry(index, hash, name);
409 if (entry != NULL && entry->is_valid_protection_domain(protection_domain)) {
410 return entry->instance_klass();
411 } else {
412 return NULL;
413 }
414 }
415
416
417 InstanceKlass* Dictionary::find_class(int index, unsigned int hash,
418 Symbol* name) {
419 assert_locked_or_safepoint(SystemDictionary_lock);
420 assert (index == index_for(name), "incorrect index?");
421
422 DictionaryEntry* entry = get_entry(index, hash, name);
423 return (entry != NULL) ? entry->instance_klass() : NULL;
424 }
425
426
427 // Variant of find_class for shared classes. No locking required, as
428 // that table is static.
429
430 InstanceKlass* Dictionary::find_shared_class(int index, unsigned int hash,
431 Symbol* name) {
432 assert (index == index_for(name), "incorrect index?");
433
434 DictionaryEntry* entry = get_entry(index, hash, name);
435 return (entry != NULL) ? entry->instance_klass() : NULL;
436 }
437
438
439 void Dictionary::add_protection_domain(int index, unsigned int hash,
440 InstanceKlass* klass,
441 Handle protection_domain,
442 TRAPS) {
443 Symbol* klass_name = klass->name();
444 DictionaryEntry* entry = get_entry(index, hash, klass_name);
445
446 assert(entry != NULL,"entry must be present, we just created it");
447 assert(protection_domain() != NULL,
448 "real protection domain should be present");
449
450 entry->add_protection_domain(this, protection_domain);
451
452 #ifdef ASSERT
453 assert(loader_data() != ClassLoaderData::the_null_class_loader_data(), "doesn't make sense");
454 #endif
455
456 assert(entry->contains_protection_domain(protection_domain()),
457 "now protection domain should be present");
458 }
459
460
461 bool Dictionary::is_valid_protection_domain(unsigned int hash,
462 Symbol* name,
463 Handle protection_domain) {
464 int index = hash_to_index(hash);
465 DictionaryEntry* entry = get_entry(index, hash, name);
466 return entry->is_valid_protection_domain(protection_domain);
467 }
468
469 #if INCLUDE_CDS
470 static bool is_jfr_event_class(Klass *k) {
471 while (k) {
472 if (k->name()->equals("jdk/jfr/Event")) {
473 return true;
474 }
475 k = k->super();
476 }
477 return false;
478 }
479
480 void Dictionary::reorder_dictionary_for_sharing() {
481
482 // Copy all the dictionary entries into a single master list.
483 assert(DumpSharedSpaces, "Should only be used at dump time");
484
485 DictionaryEntry* master_list = NULL;
486 for (int i = 0; i < table_size(); ++i) {
487 DictionaryEntry* p = bucket(i);
488 while (p != NULL) {
489 DictionaryEntry* next = p->next();
490 InstanceKlass*ik = p->instance_klass();
491 if (ik->has_signer_and_not_archived()) {
492 // We cannot include signed classes in the archive because the certificates
493 // used during dump time may be different than those used during
494 // runtime (due to expiration, etc).
495 ResourceMark rm;
496 tty->print_cr("Preload Warning: Skipping %s from signed JAR",
497 ik->name()->as_C_string());
498 free_entry(p);
499 } else if (is_jfr_event_class(ik)) {
500 // We cannot include JFR event classes because they need runtime-specific
501 // instrumentation in order to work with -XX:FlightRecorderOptions=retransform=false.
502 // There are only a small number of these classes, so it's not worthwhile to
503 // support them and make CDS more complicated.
504 ResourceMark rm;
505 tty->print_cr("Skipping JFR event class %s", ik->name()->as_C_string());
506 free_entry(p);
507 } else {
508 p->set_next(master_list);
509 master_list = p;
510 }
511 p = next;
512 }
513 set_entry(i, NULL);
514 }
515
516 // Add the dictionary entries back to the list in the correct buckets.
517 while (master_list != NULL) {
518 DictionaryEntry* p = master_list;
519 master_list = master_list->next();
520 p->set_next(NULL);
521 Symbol* class_name = p->instance_klass()->name();
522 // Since the null class loader data isn't copied to the CDS archive,
523 // compute the hash with NULL for loader data.
524 unsigned int hash = compute_hash(class_name);
525 int index = hash_to_index(hash);
526 p->set_hash(hash);
527 p->set_next(bucket(index));
528 set_entry(index, p);
529 }
530 }
531 #endif
532
533 SymbolPropertyTable::SymbolPropertyTable(int table_size)
534 : Hashtable<Symbol*, mtSymbol>(table_size, sizeof(SymbolPropertyEntry))
535 {
536 }
537 SymbolPropertyTable::SymbolPropertyTable(int table_size, HashtableBucket<mtSymbol>* t,
538 int number_of_entries)
539 : Hashtable<Symbol*, mtSymbol>(table_size, sizeof(SymbolPropertyEntry), t, number_of_entries)
540 {
541 }
542
543
544 SymbolPropertyEntry* SymbolPropertyTable::find_entry(int index, unsigned int hash,
545 Symbol* sym,
546 intptr_t sym_mode) {
547 assert(index == index_for(sym, sym_mode), "incorrect index?");
548 for (SymbolPropertyEntry* p = bucket(index); p != NULL; p = p->next()) {
549 if (p->hash() == hash && p->symbol() == sym && p->symbol_mode() == sym_mode) {
550 return p;
551 }
552 }
553 return NULL;
554 }
555
556
557 SymbolPropertyEntry* SymbolPropertyTable::add_entry(int index, unsigned int hash,
558 Symbol* sym, intptr_t sym_mode) {
559 assert_locked_or_safepoint(SystemDictionary_lock);
560 assert(index == index_for(sym, sym_mode), "incorrect index?");
561 assert(find_entry(index, hash, sym, sym_mode) == NULL, "no double entry");
562
563 SymbolPropertyEntry* p = new_entry(hash, sym, sym_mode);
564 Hashtable<Symbol*, mtSymbol>::add_entry(index, p);
565 return p;
566 }
567
568 void SymbolPropertyTable::oops_do(OopClosure* f) {
569 for (int index = 0; index < table_size(); index++) {
570 for (SymbolPropertyEntry* p = bucket(index); p != NULL; p = p->next()) {
571 if (p->method_type() != NULL) {
572 f->do_oop(p->method_type_addr());
573 }
574 }
575 }
576 }
577
578 void SymbolPropertyTable::methods_do(void f(Method*)) {
579 for (int index = 0; index < table_size(); index++) {
580 for (SymbolPropertyEntry* p = bucket(index); p != NULL; p = p->next()) {
581 Method* prop = p->method();
582 if (prop != NULL) {
583 f((Method*)prop);
584 }
585 }
586 }
587 }
588
589
590 // ----------------------------------------------------------------------------
591
592 void Dictionary::print_on(outputStream* st) const {
593 ResourceMark rm;
594
595 assert(loader_data() != NULL, "loader data should not be null");
596 st->print_cr("Java dictionary (table_size=%d, classes=%d)",
597 table_size(), number_of_entries());
598 st->print_cr("^ indicates that initiating loader is different from defining loader");
599
600 for (int index = 0; index < table_size(); index++) {
601 for (DictionaryEntry* probe = bucket(index);
602 probe != NULL;
603 probe = probe->next()) {
604 Klass* e = probe->instance_klass();
605 bool is_defining_class =
606 (loader_data() == e->class_loader_data());
607 st->print("%4d: %s%s", index, is_defining_class ? " " : "^", e->external_name());
608 ClassLoaderData* cld = e->class_loader_data();
609 if (cld == NULL) {
610 // Shared class not restored yet in shared dictionary
611 st->print(", loader data <shared, not restored>");
612 } else if (!loader_data()->is_the_null_class_loader_data()) {
613 // Class loader output for the dictionary for the null class loader data is
614 // redundant and obvious.
615 st->print(", ");
616 cld->print_value_on(st);
617 }
618 st->cr();
619 }
620 }
621 tty->cr();
622 }
623
624 void DictionaryEntry::verify() {
625 Klass* e = instance_klass();
626 guarantee(e->is_instance_klass(),
627 "Verify of dictionary failed");
628 e->verify();
629 verify_protection_domain_set();
630 }
631
632 void Dictionary::verify() {
633 guarantee(number_of_entries() >= 0, "Verify of dictionary failed");
634
635 ClassLoaderData* cld = loader_data();
636 // class loader must be present; a null class loader is the
637 // boostrap loader
638 guarantee(cld != NULL || DumpSharedSpaces ||
639 cld->class_loader() == NULL ||
640 cld->class_loader()->is_instance(),
641 "checking type of class_loader");
642
643 ResourceMark rm;
644 stringStream tempst;
645 tempst.print("System Dictionary for %s class loader", cld->loader_name_and_id());
646 verify_table<DictionaryEntry>(tempst.as_string());
647 }