1 /*
2 * Copyright (c) 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. 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 package java.net;
26
27 import jdk.internal.misc.JavaIOFileDescriptorAccess;
28 import jdk.internal.misc.SharedSecrets;
29 import jdk.internal.ref.CleanerFactory;
30 import jdk.internal.ref.PhantomCleanable;
31
32 import java.io.FileDescriptor;
33 import java.io.IOException;
34 import java.io.UncheckedIOException;
35 import java.lang.ref.Cleaner;
36
37
38 /**
39 * Cleanable for a socket/datagramsocket FileDescriptor when it becomes phantom reachable.
40 * Create a cleanup if the raw fd != -1. Windows closes sockets using the fd.
41 * Subclassed from {@code PhantomCleanable} so that {@code clear} can be
42 * called to disable the cleanup when the socket fd is closed by any means
43 * other than calling {@link FileDescriptor#close}.
44 * Otherwise, it might incorrectly close the handle or fd after it has been reused.
45 */
46 final class SocketCleanable extends PhantomCleanable<FileDescriptor> {
47
48 // Access to FileDescriptor private fields
49 private static final JavaIOFileDescriptorAccess fdAccess =
50 SharedSecrets.getJavaIOFileDescriptorAccess();
51
52 // Native function to call NET_SocketClose(fd)
53 // Used only for last chance cleanup.
54 private static native void cleanupClose0(int fd) throws IOException;
55
56 // The raw fd to close
57 private final int fd;
58
59 /**
60 * Register a socket specific Cleanable with the FileDescriptor
61 * if the FileDescriptor is non-null and the raw fd is != -1.
62 *
63 * @param fdo the FileDescriptor; may be null
64 */
65 static void register(FileDescriptor fdo) {
66 if (fdo != null && fdo.valid()) {
67 int fd = fdAccess.get(fdo);
68 fdAccess.registerCleanup(fdo,
69 new SocketCleanable(fdo, CleanerFactory.cleaner(), fd));
70 }
71 }
72
73 /**
74 * Unregister a Cleanable from the FileDescriptor.
75 * @param fdo the FileDescriptor; may be null
76 */
77 static void unregister(FileDescriptor fdo) {
78 if (fdo != null) {
79 fdAccess.unregisterCleanup(fdo);
80 }
81 }
82
83 /**
84 * Constructor for a phantom cleanable reference.
85 *
86 * @param obj the object to monitor
87 * @param cleaner the cleaner
88 * @param fd file descriptor to close
89 */
90 private SocketCleanable(FileDescriptor obj, Cleaner cleaner, int fd) {
91 super(obj, cleaner);
92 this.fd = fd;
93 }
94
95 /**
96 * Close the native handle or fd.
97 */
98 @Override
99 protected void performCleanup() {
100 try {
101 cleanupClose0(fd);
102 } catch (IOException ioe) {
103 throw new UncheckedIOException("close", ioe);
104 }
105 }
106 }
107