1/*
2 * Copyright (c) 2003, 2011, 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.  Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26package sun.security.pkcs11;
27
28import java.lang.ref.*;
29import java.util.*;
30import java.util.concurrent.atomic.AtomicInteger;
31
32import java.security.*;
33
34import sun.security.pkcs11.wrapper.*;
35
36/**
37 * A session object. Sessions are obtained via the SessionManager,
38 * see there for details. Most code will only ever need one method in
39 * this class, the id() method to obtain the session id.
40 *
41 * @author  Andreas Sterbenz
42 * @since   1.5
43 */
44final class Session implements Comparable<Session> {
45
46    // time after which to close idle sessions, in milliseconds (3 minutes)
47    private final static long MAX_IDLE_TIME = 3 * 60 * 1000;
48
49    // token instance
50    final Token token;
51
52    // session id
53    private final long id;
54
55    // number of objects created within this session
56    private final AtomicInteger createdObjects;
57
58    // time this session was last used
59    // not synchronized/volatile for performance, so may be unreliable
60    // this could lead to idle sessions being closed early, but that is harmless
61    private long lastAccess;
62
63    private final SessionRef sessionRef;
64
65    Session(Token token, long id) {
66        this.token = token;
67        this.id = id;
68        createdObjects = new AtomicInteger();
69        id();
70        sessionRef = new SessionRef(this, id, token);
71    }
72
73    public int compareTo(Session other) {
74        if (this.lastAccess == other.lastAccess) {
75            return 0;
76        } else {
77            return (this.lastAccess < other.lastAccess) ? -1 : 1;
78        }
79    }
80
81    boolean isLive(long currentTime) {
82        return currentTime - lastAccess < MAX_IDLE_TIME;
83    }
84
85    long idInternal() {
86        return id;
87    }
88
89    long id() {
90        if (token.isPresent(this.id) == false) {
91            throw new ProviderException("Token has been removed");
92        }
93        lastAccess = System.currentTimeMillis();
94        return id;
95    }
96
97    void addObject() {
98        int n = createdObjects.incrementAndGet();
99        // XXX update statistics in session manager if n == 1
100    }
101
102    void removeObject() {
103        int n = createdObjects.decrementAndGet();
104        if (n == 0) {
105            token.sessionManager.demoteObjSession(this);
106        } else if (n < 0) {
107            throw new ProviderException("Internal error: objects created " + n);
108        }
109    }
110
111    boolean hasObjects() {
112        return createdObjects.get() != 0;
113    }
114
115    void close() {
116        if (hasObjects()) {
117            throw new ProviderException(
118                "Internal error: close session with active objects");
119        }
120        sessionRef.dispose();
121    }
122}
123
124/*
125 * NOTE: Use PhantomReference here and not WeakReference
126 * otherwise the sessions maybe closed before other objects
127 * which are still being finalized.
128 */
129final class SessionRef extends PhantomReference<Session>
130        implements Comparable<SessionRef> {
131
132    private static ReferenceQueue<Session> refQueue =
133        new ReferenceQueue<Session>();
134
135    private static Set<SessionRef> refList =
136        Collections.synchronizedSortedSet(new TreeSet<SessionRef>());
137
138    static ReferenceQueue<Session> referenceQueue() {
139        return refQueue;
140    }
141
142    static int totalCount() {
143        return refList.size();
144    }
145
146    private static void drainRefQueueBounded() {
147        while (true) {
148            SessionRef next = (SessionRef) refQueue.poll();
149            if (next == null) break;
150            next.dispose();
151        }
152    }
153
154    // handle to the native session
155    private long id;
156    private Token token;
157
158    SessionRef(Session session, long id, Token token) {
159        super(session, refQueue);
160        this.id = id;
161        this.token = token;
162        refList.add(this);
163        // TBD: run at some interval and not every time?
164        drainRefQueueBounded();
165    }
166
167    void dispose() {
168        refList.remove(this);
169        try {
170            if (token.isPresent(id)) {
171                token.p11.C_CloseSession(id);
172            }
173        } catch (PKCS11Exception e1) {
174            // ignore
175        } catch (ProviderException e2) {
176            // ignore
177        } finally {
178            this.clear();
179        }
180    }
181
182    public int compareTo(SessionRef other) {
183        if (this.id == other.id) {
184            return 0;
185        } else {
186            return (this.id < other.id) ? -1 : 1;
187        }
188    }
189}
190