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 // pd_set is accessed during a safepoint.
89 while (entry->pd_set() != NULL) {
90 ProtectionDomainEntry* to_delete = entry->pd_set();
91 entry->set_pd_set(to_delete->next());
92 delete to_delete;
93 }
94 // Unlink from the Hashtable prior to freeing
95 unlink_entry(entry);
96 FREE_C_HEAP_ARRAY(char, entry);
97 }
98
99
100 bool DictionaryEntry::contains_protection_domain(oop protection_domain) const {
101 #ifdef ASSERT
102 if (protection_domain == instance_klass()->protection_domain()) {
103 // Ensure this doesn't show up in the pd_set (invariant)
104 bool in_pd_set = false;
105 for (ProtectionDomainEntry* current = pd_set_acquire();
106 current != NULL;
107 current = current->next()) {
108 if (current->protection_domain() == protection_domain) {
109 in_pd_set = true;
110 break;
111 }
112 }
113 if (in_pd_set) {
114 assert(false, "A klass's protection domain should not show up "
115 "in its sys. dict. PD set");
116 }
117 }
118 #endif /* ASSERT */
119
120 if (protection_domain == instance_klass()->protection_domain()) {
121 // Succeeds trivially
122 return true;
123 }
124
125 for (ProtectionDomainEntry* current = pd_set_acquire();
126 current != NULL;
127 current = current->next()) {
128 if (current->protection_domain() == protection_domain) return true;
129 }
130 return false;
131 }
132
133
134 void DictionaryEntry::add_protection_domain(Dictionary* dict, Handle protection_domain) {
135 assert_locked_or_safepoint(SystemDictionary_lock);
136 if (!contains_protection_domain(protection_domain())) {
137 ProtectionDomainCacheEntry* entry = SystemDictionary::cache_get(protection_domain);
138 ProtectionDomainEntry* new_head =
139 new ProtectionDomainEntry(entry, pd_set());
140 // Warning: Preserve store ordering. The SystemDictionary is read
141 // without locks. The new ProtectionDomainEntry must be
142 // complete before other threads can be allowed to see it
143 // via a store to _pd_set.
144 release_set_pd_set(new_head);
145 }
146 LogTarget(Trace, protectiondomain) lt;
147 if (lt.is_enabled()) {
148 LogStream ls(lt);
149 print_count(&ls);
150 }
151 }
152
153
154 void Dictionary::do_unloading() {
155 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
156
157 // The NULL class loader doesn't initiate loading classes from other class loaders
158 if (loader_data() == ClassLoaderData::the_null_class_loader_data()) {
159 return;
160 }
161
162 // Remove unloaded entries and classes from this dictionary
163 DictionaryEntry* probe = NULL;
164 for (int index = 0; index < table_size(); index++) {
165 for (DictionaryEntry** p = bucket_addr(index); *p != NULL; ) {
166 probe = *p;
167 InstanceKlass* ik = probe->instance_klass();
168 ClassLoaderData* k_def_class_loader_data = ik->class_loader_data();
169
170 // If the klass that this loader initiated is dead,
171 // (determined by checking the defining class loader)
172 // remove this entry.
173 if (k_def_class_loader_data->is_unloading()) {
174 assert(k_def_class_loader_data != loader_data(),
175 "cannot have live defining loader and unreachable klass");
176 *p = probe->next();
177 free_entry(probe);
178 continue;
179 }
180 p = probe->next_addr();
181 }
182 }
183 }
184
185 void Dictionary::remove_classes_in_error_state() {
186 assert(DumpSharedSpaces, "supported only when dumping");
187 DictionaryEntry* probe = NULL;
188 for (int index = 0; index < table_size(); index++) {
189 for (DictionaryEntry** p = bucket_addr(index); *p != NULL; ) {
190 probe = *p;
191 InstanceKlass* ik = probe->instance_klass();
192 if (ik->is_in_error_state()) { // purge this entry
193 *p = probe->next();
194 free_entry(probe);
195 ResourceMark rm;
196 tty->print_cr("Preload Warning: Removed error class: %s", ik->external_name());
197 continue;
198 }
199
200 p = probe->next_addr();
201 }
202 }
203 }
204
205 // Just the classes from defining class loaders
206 void Dictionary::classes_do(void f(InstanceKlass*)) {
207 for (int index = 0; index < table_size(); index++) {
208 for (DictionaryEntry* probe = bucket(index);
209 probe != NULL;
210 probe = probe->next()) {
211 InstanceKlass* k = probe->instance_klass();
212 if (loader_data() == k->class_loader_data()) {
213 f(k);
214 }
215 }
216 }
217 }
218
219 // Added for initialize_itable_for_klass to handle exceptions
220 // Just the classes from defining class loaders
221 void Dictionary::classes_do(void f(InstanceKlass*, TRAPS), TRAPS) {
222 for (int index = 0; index < table_size(); index++) {
223 for (DictionaryEntry* probe = bucket(index);
224 probe != NULL;
225 probe = probe->next()) {
226 InstanceKlass* k = probe->instance_klass();
227 if (loader_data() == k->class_loader_data()) {
228 f(k, CHECK);
229 }
230 }
231 }
232 }
233
234 // All classes, and their class loaders, including initiating class loaders
235 void Dictionary::all_entries_do(void f(InstanceKlass*, ClassLoaderData*)) {
236 for (int index = 0; index < table_size(); index++) {
237 for (DictionaryEntry* probe = bucket(index);
238 probe != NULL;
239 probe = probe->next()) {
240 InstanceKlass* k = probe->instance_klass();
241 f(k, loader_data());
242 }
243 }
244 }
245
246 // Used to scan and relocate the classes during CDS archive dump.
247 void Dictionary::classes_do(MetaspaceClosure* it) {
248 assert(DumpSharedSpaces, "dump-time only");
249 for (int index = 0; index < table_size(); index++) {
250 for (DictionaryEntry* probe = bucket(index);
251 probe != NULL;
252 probe = probe->next()) {
253 it->push(probe->klass_addr());
254 ((SharedDictionaryEntry*)probe)->metaspace_pointers_do(it);
255 }
256 }
257 }
258
259
260
261 // Add a loaded class to the dictionary.
262 // Readers of the SystemDictionary aren't always locked, so _buckets
263 // is volatile. The store of the next field in the constructor is
264 // also cast to volatile; we do this to ensure store order is maintained
265 // by the compilers.
266
267 void Dictionary::add_klass(int index, unsigned int hash, Symbol* class_name,
268 InstanceKlass* obj) {
269 assert_locked_or_safepoint(SystemDictionary_lock);
270 assert(obj != NULL, "adding NULL obj");
271 assert(obj->name() == class_name, "sanity check on name");
272
273 DictionaryEntry* entry = new_entry(hash, obj);
274 add_entry(index, entry);
275 }
276
277
278 // This routine does not lock the dictionary.
279 //
280 // Since readers don't hold a lock, we must make sure that system
281 // dictionary entries are only removed at a safepoint (when only one
282 // thread is running), and are added to in a safe way (all links must
283 // be updated in an MT-safe manner).
284 //
285 // Callers should be aware that an entry could be added just after
286 // _buckets[index] is read here, so the caller will not see the new entry.
287 DictionaryEntry* Dictionary::get_entry(int index, unsigned int hash,
288 Symbol* class_name) {
289 for (DictionaryEntry* entry = bucket(index);
290 entry != NULL;
291 entry = entry->next()) {
292 if (entry->hash() == hash && entry->equals(class_name)) {
293 if (!DumpSharedSpaces || SystemDictionaryShared::is_builtin(entry)) {
294 return entry;
295 }
296 }
297 }
298 return NULL;
299 }
300
301
302 InstanceKlass* Dictionary::find(int index, unsigned int hash, Symbol* name,
303 Handle protection_domain) {
304 DictionaryEntry* entry = get_entry(index, hash, name);
305 if (entry != NULL && entry->is_valid_protection_domain(protection_domain)) {
306 return entry->instance_klass();
307 } else {
308 return NULL;
309 }
310 }
311
312
313 InstanceKlass* Dictionary::find_class(int index, unsigned int hash,
314 Symbol* name) {
315 assert_locked_or_safepoint(SystemDictionary_lock);
316 assert (index == index_for(name), "incorrect index?");
317
318 DictionaryEntry* entry = get_entry(index, hash, name);
319 return (entry != NULL) ? entry->instance_klass() : NULL;
320 }
321
322
323 // Variant of find_class for shared classes. No locking required, as
324 // that table is static.
325
326 InstanceKlass* Dictionary::find_shared_class(int index, unsigned int hash,
327 Symbol* name) {
328 assert (index == index_for(name), "incorrect index?");
329
330 DictionaryEntry* entry = get_entry(index, hash, name);
331 return (entry != NULL) ? entry->instance_klass() : NULL;
332 }
333
334
335 void Dictionary::add_protection_domain(int index, unsigned int hash,
336 InstanceKlass* klass,
337 Handle protection_domain,
338 TRAPS) {
339 Symbol* klass_name = klass->name();
340 DictionaryEntry* entry = get_entry(index, hash, klass_name);
341
342 assert(entry != NULL,"entry must be present, we just created it");
343 assert(protection_domain() != NULL,
344 "real protection domain should be present");
345
346 entry->add_protection_domain(this, protection_domain);
347
348 assert(entry->contains_protection_domain(protection_domain()),
349 "now protection domain should be present");
350 }
351
352
353 bool Dictionary::is_valid_protection_domain(int index, unsigned int hash,
354 Symbol* name,
355 Handle protection_domain) {
356 DictionaryEntry* entry = get_entry(index, hash, name);
357 return entry->is_valid_protection_domain(protection_domain);
358 }
359
360
361 void Dictionary::reorder_dictionary_for_sharing() {
362
363 // Copy all the dictionary entries into a single master list.
364
365 DictionaryEntry* master_list = NULL;
366 for (int i = 0; i < table_size(); ++i) {
367 DictionaryEntry* p = bucket(i);
368 while (p != NULL) {
369 DictionaryEntry* next = p->next();
370 InstanceKlass*ik = p->instance_klass();
371 // we cannot include signed classes in the archive because the certificates
372 // used during dump time may be different than those used during
373 // runtime (due to expiration, etc).
374 if (ik->signers() != NULL) {
375 ResourceMark rm;
376 tty->print_cr("Preload Warning: Skipping %s from signed JAR",
377 ik->name()->as_C_string());
378 free_entry(p);
379 } else {
380 p->set_next(master_list);
381 master_list = p;
382 }
383 p = next;
384 }
385 set_entry(i, NULL);
386 }
387
388 // Add the dictionary entries back to the list in the correct buckets.
389 while (master_list != NULL) {
390 DictionaryEntry* p = master_list;
391 master_list = master_list->next();
392 p->set_next(NULL);
393 Symbol* class_name = p->instance_klass()->name();
394 // Since the null class loader data isn't copied to the CDS archive,
395 // compute the hash with NULL for loader data.
396 unsigned int hash = compute_hash(class_name);
397 int index = hash_to_index(hash);
398 p->set_hash(hash);
399 p->set_next(bucket(index));
400 set_entry(index, p);
401 }
402 }
403
404
405 SymbolPropertyTable::SymbolPropertyTable(int table_size)
406 : Hashtable<Symbol*, mtSymbol>(table_size, sizeof(SymbolPropertyEntry))
407 {
408 }
409 SymbolPropertyTable::SymbolPropertyTable(int table_size, HashtableBucket<mtSymbol>* t,
410 int number_of_entries)
411 : Hashtable<Symbol*, mtSymbol>(table_size, sizeof(SymbolPropertyEntry), t, number_of_entries)
412 {
413 }
414
415
416 SymbolPropertyEntry* SymbolPropertyTable::find_entry(int index, unsigned int hash,
417 Symbol* sym,
418 intptr_t sym_mode) {
419 assert(index == index_for(sym, sym_mode), "incorrect index?");
420 for (SymbolPropertyEntry* p = bucket(index); p != NULL; p = p->next()) {
421 if (p->hash() == hash && p->symbol() == sym && p->symbol_mode() == sym_mode) {
422 return p;
423 }
424 }
425 return NULL;
426 }
427
428
429 SymbolPropertyEntry* SymbolPropertyTable::add_entry(int index, unsigned int hash,
430 Symbol* sym, intptr_t sym_mode) {
431 assert_locked_or_safepoint(SystemDictionary_lock);
432 assert(index == index_for(sym, sym_mode), "incorrect index?");
433 assert(find_entry(index, hash, sym, sym_mode) == NULL, "no double entry");
434
435 SymbolPropertyEntry* p = new_entry(hash, sym, sym_mode);
436 Hashtable<Symbol*, mtSymbol>::add_entry(index, p);
437 return p;
438 }
439
440 void SymbolPropertyTable::oops_do(OopClosure* f) {
441 for (int index = 0; index < table_size(); index++) {
442 for (SymbolPropertyEntry* p = bucket(index); p != NULL; p = p->next()) {
443 if (p->method_type() != NULL) {
444 f->do_oop(p->method_type_addr());
445 }
446 }
447 }
448 }
449
450 void SymbolPropertyTable::methods_do(void f(Method*)) {
451 for (int index = 0; index < table_size(); index++) {
452 for (SymbolPropertyEntry* p = bucket(index); p != NULL; p = p->next()) {
453 Method* prop = p->method();
454 if (prop != NULL) {
455 f((Method*)prop);
456 }
457 }
458 }
459 }
460
461
462 // ----------------------------------------------------------------------------
463
464 void Dictionary::print_on(outputStream* st) const {
465 ResourceMark rm;
466
467 assert(loader_data() != NULL, "loader data should not be null");
468 st->print_cr("Java dictionary (table_size=%d, classes=%d)",
469 table_size(), number_of_entries());
470 st->print_cr("^ indicates that initiating loader is different from defining loader");
471
472 for (int index = 0; index < table_size(); index++) {
473 for (DictionaryEntry* probe = bucket(index);
474 probe != NULL;
475 probe = probe->next()) {
476 Klass* e = probe->instance_klass();
477 bool is_defining_class =
478 (loader_data() == e->class_loader_data());
479 st->print("%4d: %s%s, loader ", index, is_defining_class ? " " : "^", e->external_name());
480 ClassLoaderData* loader_data = e->class_loader_data();
481 if (loader_data == NULL) {
482 // Shared class not restored yet in shared dictionary
483 st->print("<shared, not restored>");
484 } else {
485 loader_data->print_value_on(st);
486 }
487 st->cr();
488 }
489 }
490 tty->cr();
491 }
492
493 void DictionaryEntry::verify() {
494 Klass* e = instance_klass();
495 guarantee(e->is_instance_klass(),
496 "Verify of dictionary failed");
497 e->verify();
498 verify_protection_domain_set();
499 }
500
501 void Dictionary::verify() {
502 guarantee(number_of_entries() >= 0, "Verify of dictionary failed");
503
504 ClassLoaderData* cld = loader_data();
505 // class loader must be present; a null class loader is the
506 // boostrap loader
507 guarantee(cld != NULL || DumpSharedSpaces ||
508 cld->class_loader() == NULL ||
509 cld->class_loader()->is_instance(),
510 "checking type of class_loader");
511
512 ResourceMark rm;
513 stringStream tempst;
514 tempst.print("System Dictionary for %s", cld->loader_name());
515 verify_table<DictionaryEntry>(tempst.as_string());
516 }