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.access.JavaIOFileDescriptorAccess; 28 import jdk.internal.access.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 }