1 /*
  2  * Copyright (c) 2017, 2023, 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 sun.nio.ch;
 26 
 27 import java.io.IOException;
 28 import java.io.UncheckedIOException;
 29 import java.lang.ref.Cleaner.Cleanable;
 30 import jdk.internal.ref.CleanerFactory;
 31 import static sun.nio.ch.KQueue.*;
 32 
 33 /**
 34  * Poller implementation based on the kqueue facility.
 35  */
 36 class KQueuePoller extends Poller {
 37     private final int kqfd;
 38     private final int filter;
 39     private final int maxEvents;
 40     private final long address;
 41     private final Cleanable cleaner;
 42 
 43     KQueuePoller(boolean subPoller, boolean read) throws IOException {
 44         this.kqfd = KQueue.create();
 45         this.filter = (read) ? EVFILT_READ : EVFILT_WRITE;
 46         this.maxEvents = (subPoller) ? 64 : 512;
 47         this.address = KQueue.allocatePollArray(maxEvents);
 48         if (subPoller) {
 49             this.cleaner = CleanerFactory.cleaner().register(this, release(kqfd, address));
 50         } else {
 51             this.cleaner = null;
 52         }
 53     }
 54 
 55     @Override
 56     void close() {
 57         cleaner.clean();
 58     }
 59 
 60     /**
 61      * Closes kernel event queue and release poll array.
 62      */
 63     private static Runnable release(int kqfd, long address) {
 64         return () -> {
 65             try {
 66                 FileDispatcherImpl.closeIntFD(kqfd);
 67             } catch (IOException ioe) {
 68                 throw new UncheckedIOException(ioe);
 69             } finally {
 70                 // release memory
 71                 KQueue.freePollArray(address);
 72             }
 73         };
 74     }
 75 
 76     @Override
 77     int fdVal() {
 78         return kqfd;
 79     }
 80 
 81     @Override
 82     void implRegister(int fdVal) throws IOException {
 83         int err = KQueue.register(kqfd, fdVal, filter, (EV_ADD|EV_ONESHOT));
 84         if (err != 0)
 85             throw new IOException("kevent failed: " + err);
 86     }
 87 
 88     @Override
 89     void implDeregister(int fdVal, boolean polled) {
 90         // event was deleted if already polled
 91         if (!polled) {
 92             KQueue.register(kqfd, fdVal, filter, EV_DELETE);
 93         }
 94     }
 95 
 96     @Override
 97     int poll(int timeout) throws IOException {
 98         int n = KQueue.poll(kqfd, address, maxEvents, timeout);
 99         int i = 0;
100         while (i < n) {
101             long keventAddress = KQueue.getEvent(address, i);
102             int fdVal = KQueue.getDescriptor(keventAddress);
103             polled(fdVal);
104             i++;
105         }
106         return n;
107     }
108 }