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 {
48 }
49
50 void ProtectionDomainCacheTable::unlink() {
51 assert(SafepointSynchronize::is_at_safepoint(), "must be");
52 for (int i = 0; i < table_size(); ++i) {
53 ProtectionDomainCacheEntry** p = bucket_addr(i);
54 ProtectionDomainCacheEntry* entry = bucket(i);
55 while (entry != NULL) {
56 oop pd = entry->object_no_keepalive();
57 if (pd != NULL) {
58 p = entry->next_addr();
59 } else {
60 LogTarget(Debug, protectiondomain) lt;
61 if (lt.is_enabled()) {
62 LogStream ls(lt);
63 ls.print_cr("protection domain unlinked at %d", i);
64 }
65 entry->literal().release();
66 *p = entry->next();
67 free_entry(entry);
68 }
69 entry = *p;
70 }
71 }
72 }
73
74 void ProtectionDomainCacheTable::print_on(outputStream* st) const {
75 st->print_cr("Protection domain cache table (table_size=%d, classes=%d)",
76 table_size(), number_of_entries());
77 for (int index = 0; index < table_size(); index++) {
78 for (ProtectionDomainCacheEntry* probe = bucket(index);
79 probe != NULL;
80 probe = probe->next()) {
81 st->print_cr("%4d: protection_domain: " PTR_FORMAT, index, p2i(probe->object_no_keepalive()));
82 }
83 }
84 }
85
86 void ProtectionDomainCacheTable::verify() {
87 verify_table<ProtectionDomainCacheEntry>("Protection Domain Table");
88 }
89
90 oop ProtectionDomainCacheEntry::object() {
91 return literal().resolve();
92 }
93
94 oop ProtectionDomainEntry::object() {
95 return _pd_cache->object();
96 }
97
98 // The object_no_keepalive() call peeks at the phantomly reachable oop without
99 // keeping it alive. This is okay to do in the VM thread state if it is not
100 // leaked out to become strongly reachable.
101 oop ProtectionDomainCacheEntry::object_no_keepalive() {
102 return literal().peek();
103 }
104
105 oop ProtectionDomainEntry::object_no_keepalive() {
106 return _pd_cache->object_no_keepalive();
107 }
108
109 void ProtectionDomainCacheEntry::verify() {
110 guarantee(object_no_keepalive() == NULL || oopDesc::is_oop(object_no_keepalive()), "must be an oop");
111 }
112
113 ProtectionDomainCacheEntry* ProtectionDomainCacheTable::get(Handle protection_domain) {
114 unsigned int hash = compute_hash(protection_domain);
115 int index = hash_to_index(hash);
116
117 ProtectionDomainCacheEntry* entry = find_entry(index, protection_domain);
118 if (entry == NULL) {
119 entry = add_entry(index, hash, protection_domain);
120 }
121 // keep entry alive
122 (void)entry->object();
123 return entry;
124 }
125
126 ProtectionDomainCacheEntry* ProtectionDomainCacheTable::find_entry(int index, Handle protection_domain) {
127 for (ProtectionDomainCacheEntry* e = bucket(index); e != NULL; e = e->next()) {
128 if (oopDesc::equals(e->object_no_keepalive(), protection_domain())) {
129 return e;
130 }
131 }
132
133 return NULL;
134 }
135
136 ProtectionDomainCacheEntry* ProtectionDomainCacheTable::add_entry(int index, unsigned int hash, Handle protection_domain) {
137 assert_locked_or_safepoint(SystemDictionary_lock);
138 assert(index == index_for(protection_domain), "incorrect index?");
139 assert(find_entry(index, protection_domain) == NULL, "no double entry");
140
141 ClassLoaderWeakHandle w = ClassLoaderWeakHandle::create(protection_domain);
142 ProtectionDomainCacheEntry* p = new_entry(hash, w);
143 Hashtable<ClassLoaderWeakHandle, mtClass>::add_entry(index, p);
144 return p;
145 }