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