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