/*

 * Copyright (c) 2013, 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.

 *

 * 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

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

/*

 * @test

 * @bug 8021820

 * @summary The total number of file descriptors is limited to

 * 1024(FDSET_SIZE) on MacOSX (the size of fd array passed to select()

 * call in java.net classes is limited to this value).

 * @run main/othervm SelectFdsLimit

 * @author aleksej.efimov@oracle.com

 */

import java.io.File;

import java.io.FileInputStream;

import java.io.FileNotFoundException;

import java.io.IOException;

import java.io.InputStream;

import java.net.ServerSocket;

import java.net.SocketTimeoutException;

/*

 * Test must be run in othervm mode to ensure that all files

 * opened by openFiles() are closed propertly.

*/

public class SelectFdsLimit {

    static final int FDTOOPEN = 1023;

    static final String TESTFILE = "testfile";

    static FileInputStream [] testFIS;

    static void prepareTestEnv() throws IOException {

            File fileToCreate = new File(TESTFILE);

            if (!fileToCreate.exists())

                if (!fileToCreate.createNewFile())

                    throw new RuntimeException("Can't create test file");

    }

    //If there will be some problem (i.e. ulimits on number of opened files will fail)

    //then this method will fail with exception and test will be considered as

    //failed. But allocated fds will be released because the test is executed by

    //dedicated VM (@run main/othervm).

    static void openFiles(int fn, File f) throws FileNotFoundException, IOException {

        testFIS = new FileInputStream[FDTOOPEN];

        for (;;) {

            if (0 == fn)

                break;

            FileInputStream fis = new FileInputStream(f);

            testFIS[--fn] = fis;

        }

    }

    public static void main(String [] args) throws IOException, FileNotFoundException {

        //The bug 8021820 is a Mac specific and because of that test will pass on all

        //other platforms

        if (!System.getProperty("os.name").contains("OS X")) {

           return;

        }

        //Create test directory with test files

        prepareTestEnv();

        //Consume FD ids for this java process to overflow the 1024

        openFiles(FDTOOPEN,new File(TESTFILE));

        //Wait for incoming connection and make the select() used in java.net

        //classes fail the limitation on FDSET_SIZE

        ServerSocket socket = new ServerSocket(0);

        //Set the minimal timeout, no one is

        //going to connect to this server socket

        socket.setSoTimeout(1);

        // The accept() call will throw SocketException if the

        // select() has failed due to limitation on fds size,

        // indicating test failure. A SocketTimeoutException

        // is expected, so it is caught and ignored, and the test

        // passes.

        try {

           socket.accept();

        } catch (SocketTimeoutException e) { }

    }

}