1 /*
2 * Copyright (c) 2017, 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/protectionDomainCache.hpp"
27 #include "classfile/systemDictionary.hpp"
28 #include "logging/log.hpp"
29 #include "logging/logStream.hpp"
30 #include "memory/iterator.hpp"
31 #include "memory/resourceArea.hpp"
32 #include "oops/oop.inline.hpp"
33 #include "oops/weakHandle.inline.hpp"
34 #include "utilities/hashtable.inline.hpp"
35
36 unsigned int ProtectionDomainCacheTable::compute_hash(Handle protection_domain) {
37 // Identity hash can safepoint, so keep protection domain in a Handle.
38 return (unsigned int)(protection_domain->identity_hash());
39 }
40
41 int ProtectionDomainCacheTable::index_for(Handle protection_domain) {
42 return hash_to_index(compute_hash(protection_domain));
43 }
44
45 ProtectionDomainCacheTable::ProtectionDomainCacheTable(int table_size)
46 : Hashtable<ClassLoaderWeakHandle, mtClass>(table_size, sizeof(ProtectionDomainCacheEntry))
47 { _dead_entries = false;
48 _total_oops_removed = 0;
49 }
50
51 void ProtectionDomainCacheTable::trigger_cleanup() {
52 MutexLockerEx ml(Service_lock, Mutex::_no_safepoint_check_flag);
53 _dead_entries = true;
54 Service_lock->notify_all();
55 }
56
57 void ProtectionDomainCacheTable::unlink() {
58 MutexLocker ml(SystemDictionary_lock);
59 int oops_removed = 0;
60 for (int i = 0; i < table_size(); ++i) {
61 ProtectionDomainCacheEntry** p = bucket_addr(i);
62 ProtectionDomainCacheEntry* entry = bucket(i);
63 while (entry != NULL) {
64 oop pd = entry->object_no_keepalive();
65 if (pd != NULL) {
66 p = entry->next_addr();
67 } else {
68 oops_removed++;
69 LogTarget(Debug, protectiondomain, table) lt;
70 if (lt.is_enabled()) {
71 LogStream ls(lt);
72 ls.print_cr("protection domain unlinked at %d", i);
73 }
74 entry->literal().release();
75 *p = entry->next();
76 free_entry(entry);
77 }
78 entry = *p;
79 }
80 }
81 _total_oops_removed += oops_removed;
82 _dead_entries = false;
83 }
84
85 void ProtectionDomainCacheTable::print_on(outputStream* st) const {
86 assert_locked_or_safepoint(SystemDictionary_lock);
87 st->print_cr("Protection domain cache table (table_size=%d, classes=%d)",
88 table_size(), number_of_entries());
89 for (int index = 0; index < table_size(); index++) {
90 for (ProtectionDomainCacheEntry* probe = bucket(index);
91 probe != NULL;
92 probe = probe->next()) {
93 st->print_cr("%4d: protection_domain: " PTR_FORMAT, index, p2i(probe->object_no_keepalive()));
94 }
95 }
96 }
97
98 void ProtectionDomainCacheTable::verify() {
99 verify_table<ProtectionDomainCacheEntry>("Protection Domain Table");
100 }
101
102 oop ProtectionDomainCacheEntry::object() {
103 return literal().resolve();
104 }
105
106 oop ProtectionDomainEntry::object() {
107 return _pd_cache->object();
108 }
109
110 // The object_no_keepalive() call peeks at the phantomly reachable oop without
111 // keeping it alive. This is okay to do in the VM thread state if it is not
112 // leaked out to become strongly reachable.
113 oop ProtectionDomainCacheEntry::object_no_keepalive() {
114 return literal().peek();
115 }
116
117 oop ProtectionDomainEntry::object_no_keepalive() {
118 return _pd_cache->object_no_keepalive();
119 }
120
121 void ProtectionDomainCacheEntry::verify() {
122 guarantee(object_no_keepalive() == NULL || oopDesc::is_oop(object_no_keepalive()), "must be an oop");
123 }
124
125 ProtectionDomainCacheEntry* ProtectionDomainCacheTable::get(Handle protection_domain) {
126 unsigned int hash = compute_hash(protection_domain);
127 int index = hash_to_index(hash);
128
129 ProtectionDomainCacheEntry* entry = find_entry(index, protection_domain);
130 if (entry == NULL) {
131 entry = add_entry(index, hash, protection_domain);
132 }
133 // keep entry alive
134 (void)entry->object();
135 return entry;
136 }
137
138 ProtectionDomainCacheEntry* ProtectionDomainCacheTable::find_entry(int index, Handle protection_domain) {
139 assert_locked_or_safepoint(SystemDictionary_lock);
140 for (ProtectionDomainCacheEntry* e = bucket(index); e != NULL; e = e->next()) {
141 if (oopDesc::equals(e->object_no_keepalive(), protection_domain())) {
142 return e;
143 }
144 }
145
146 return NULL;
147 }
148
149 ProtectionDomainCacheEntry* ProtectionDomainCacheTable::add_entry(int index, unsigned int hash, Handle protection_domain) {
150 assert_locked_or_safepoint(SystemDictionary_lock);
151 assert(index == index_for(protection_domain), "incorrect index?");
152 assert(find_entry(index, protection_domain) == NULL, "no double entry");
153
154 LogTarget(Debug, protectiondomain, table) lt;
155 if (lt.is_enabled()) {
156 LogStream ls(lt);
157 ls.print("protection domain added ");
158 protection_domain->print_value_on(&ls);
159 ls.cr();
160 }
161 ClassLoaderWeakHandle w = ClassLoaderWeakHandle::create(protection_domain);
162 ProtectionDomainCacheEntry* p = new_entry(hash, w);
163 Hashtable<ClassLoaderWeakHandle, mtClass>::add_entry(index, p);
164 return p;
165 }