/*
* Copyright (c) 2011, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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*/
package sun.net;
import java.net.SocketException;
import java.util.concurrent.atomic.AtomicInteger;
import sun.security.action.GetPropertyAction;
/**
* Manages count of total number of UDP sockets and ensures
* that exception is thrown if we try to create more than the
* configured limit.
*
* This functionality could be put in NetHooks some time in future.
*/
public class ResourceManager {
/* default maximum number of udp sockets per VM
* when a security manager is enabled.
* The default is 1024 which is high enough to be useful
* but low enough to be well below the maximum number
* of port numbers actually available on all OSes for
* such sockets (5000 on some versions of windows)
*/
private static final int DEFAULT_MAX_SOCKETS = 1024;
private static final int maxSockets;
private static final AtomicInteger numSockets;
static {
String prop = java.security.AccessController.doPrivileged(
new GetPropertyAction("sun.net.maxDatagramSockets")
);
int defmax = DEFAULT_MAX_SOCKETS;
try {
if (prop != null) {
defmax = Integer.parseInt(prop);
}
} catch (NumberFormatException e) {}
maxSockets = defmax;
numSockets = new AtomicInteger(0);
}
public static void beforeUdpCreate() throws SocketException {
if (System.getSecurityManager() != null) {
if (numSockets.incrementAndGet() > maxSockets) {
numSockets.decrementAndGet();
throw new SocketException("maximum number of DatagramSockets reached");
}
}
}
public static void afterUdpClose() {
if (System.getSecurityManager() != null) {
numSockets.decrementAndGet();
}
}
}