84 lines
3.0 KiB
Java
84 lines
3.0 KiB
Java
/*
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* Copyright (c) 2011, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation. Oracle designates this
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* particular file as subject to the "Classpath" exception as provided
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* by Oracle in the LICENSE file that accompanied this code.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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package sun.net;
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import java.net.SocketException;
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import java.util.concurrent.atomic.AtomicInteger;
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import sun.security.action.GetPropertyAction;
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/**
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* Manages count of total number of UDP sockets and ensures
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* that exception is thrown if we try to create more than the
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* configured limit.
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*
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* This functionality could be put in NetHooks some time in future.
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*/
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public class ResourceManager {
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/* default maximum number of udp sockets per VM
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* when a security manager is enabled.
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* The default is 25 which is high enough to be useful
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* but low enough to be well below the maximum number
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* of port numbers actually available on all OSes
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* when multiplied by the maximum feasible number of VM processes
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* that could practically be spawned.
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*/
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private static final int DEFAULT_MAX_SOCKETS = 25;
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private static final int maxSockets;
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private static final AtomicInteger numSockets;
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static {
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String prop = java.security.AccessController.doPrivileged(
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new GetPropertyAction("sun.net.maxDatagramSockets")
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);
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int defmax = DEFAULT_MAX_SOCKETS;
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try {
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if (prop != null) {
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defmax = Integer.parseInt(prop);
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}
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} catch (NumberFormatException e) {}
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maxSockets = defmax;
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numSockets = new AtomicInteger(0);
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}
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public static void beforeUdpCreate() throws SocketException {
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if (System.getSecurityManager() != null) {
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if (numSockets.incrementAndGet() > maxSockets) {
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numSockets.decrementAndGet();
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throw new SocketException("maximum number of DatagramSockets reached");
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}
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}
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}
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public static void afterUdpClose() {
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if (System.getSecurityManager() != null) {
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numSockets.decrementAndGet();
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}
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}
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}
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