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| 1 | +/* | |
| 2 | + * Copyright (c) 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 | + | |
| 26 | +package sun.net; | |
| 27 | + | |
| 28 | +import java.net.SocketException; | |
| 29 | +import java.util.concurrent.atomic.AtomicInteger; | |
| 30 | +import sun.security.action.GetPropertyAction; | |
| 31 | + | |
| 32 | +/** | |
| 33 | + * Manages count of total number of UDP sockets and ensures | |
| 34 | + * that exception is thrown if we try to create more than the | |
| 35 | + * configured limit. | |
| 36 | + * | |
| 37 | + * This functionality could be put in NetHooks some time in future. | |
| 38 | + */ | |
| 39 | + | |
| 40 | +public class ResourceManager { | |
| 41 | + | |
| 42 | + /* default maximum number of udp sockets per VM | |
| 43 | + * when a security manager is enabled. | |
| 44 | + * The default is 1024 which is high enough to be useful | |
| 45 | + * but low enough to be well below the maximum number | |
| 46 | + * of port numbers actually available on all OSes for | |
| 47 | + * such sockets (5000 on some versions of windows) | |
| 48 | + */ | |
| 49 | + | |
| 50 | + private static final int DEFAULT_MAX_SOCKETS = 1024; | |
| 51 | + private static final int maxSockets; | |
| 52 | + private static final AtomicInteger numSockets; | |
| 53 | + | |
| 54 | + static { | |
| 55 | + String prop = java.security.AccessController.doPrivileged( | |
| 56 | + new GetPropertyAction("sun.net.maxDatagramSockets") | |
| 57 | + ); | |
| 58 | + int defmax = DEFAULT_MAX_SOCKETS; | |
| 59 | + try { | |
| 60 | + if (prop != null) { | |
| 61 | + defmax = Integer.parseInt(prop); | |
| 62 | + } | |
| 63 | + } catch (NumberFormatException e) {} | |
| 64 | + maxSockets = defmax; | |
| 65 | + numSockets = new AtomicInteger(0); | |
| 66 | + } | |
| 67 | + | |
| 68 | + public static void beforeUdpCreate() throws SocketException { | |
| 69 | + if (System.getSecurityManager() != null) { | |
| 70 | + if (numSockets.incrementAndGet() > maxSockets) { | |
| 71 | + numSockets.decrementAndGet(); | |
| 72 | + throw new SocketException("maximum number of DatagramSockets reached"); | |
| 73 | + } | |
| 74 | + } | |
| 75 | + } | |
| 76 | + | |
| 77 | + public static void afterUdpClose() { | |
| 78 | + if (System.getSecurityManager() != null) { | |
| 79 | + numSockets.decrementAndGet(); | |
| 80 | + } | |
| 81 | + } | |
| 82 | +} | |