1 /*

     2  * Copyright (c) 2011, 2018, 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 /*

    27  * KQueueArrayWrapper.java

    28  * Implementation of Selector using FreeBSD / Mac OS X kqueues

    29  * Derived from Sun's DevPollArrayWrapper

    30  */

    31 

    32 package sun.nio.ch;

    33 

    34 import java.io.IOException;

    35 import java.util.Iterator;

    36 import java.util.LinkedList;

    37 import sun.security.action.GetPropertyAction;

    38 

    39 /*

    40  * struct kevent {           // 32-bit    64-bit

    41  *     uintptr_t ident;      //   4         8

    42  *     short     filter;     //   2         2

    43  *     u_short   flags;      //   2         2

    44  *     u_int     fflags;     //   4         4

    45  *     intptr_t  data;       //   4         8

    46  *     void      *udata;     //   4         8

    47  * }                  // Total:  20        32

    48  *

    49  * The implementation works in 32-bit and 64-bit world. We do this by calling a

    50  * native function that actually sets the sizes and offsets of the fields based

    51  * on which mode we're in.

    52  */

    53 

    54 class KQueueArrayWrapper {

    55     // kevent filters

    56     static short EVFILT_READ;

    57     static short EVFILT_WRITE;

    58 

    59     // kevent struct

    60     // These fields are now set by initStructSizes in the static initializer.

    61     static short SIZEOF_KEVENT;

    62     static short FD_OFFSET;

    63     static short FILTER_OFFSET;

    64 

    65     // kevent array size

    66     static final int NUM_KEVENTS = 128;

    67 

    68     // Are we in a 64-bit VM?

    69     static boolean is64bit;

    70 

    71     // The kevent array (used for outcoming events only)

    72     private final AllocatedNativeObject keventArray;

    73     private final long keventArrayAddress;

    74 

    75     // The kqueue fd

    76     private final int kq;

    77 

    78     // The fd of the interrupt line going out

    79     private final int outgoingInterruptFD;

    80 

    81 

    82     static {

    83         IOUtil.load();

    84         initStructSizes();

    85         String datamodel =

    86                 GetPropertyAction.privilegedGetProperty("sun.arch.data.model");

    87         is64bit = "64".equals(datamodel);

    88     }

    89 

    90     KQueueArrayWrapper(int fd0, int fd1) throws IOException {

    91         int allocationSize = SIZEOF_KEVENT * NUM_KEVENTS;

    92         keventArray = new AllocatedNativeObject(allocationSize, true);

    93         keventArrayAddress = keventArray.address();

    94         kq = init();

    95         register0(kq, fd0, 1, 0);

    96         outgoingInterruptFD = fd1;

    97     }

    98 

    99     // Used to update file description registrations

   100     private static class Update {

   101         SelChImpl channel;

   102         int events;

   103         Update(SelChImpl channel, int events) {

   104             this.channel = channel;

   105             this.events = events;

   106         }

   107     }

   108 

   109     private LinkedList<Update> updateList = new LinkedList<Update>();

   110 

   111     int getReventOps(int index) {

   112         int result = 0;

   113         int offset = SIZEOF_KEVENT*index + FILTER_OFFSET;

   114         short filter = keventArray.getShort(offset);

   115 

   116         // This is all that's necessary based on inspection of usage:

   117         //   SinkChannelImpl, SourceChannelImpl, DatagramChannelImpl,

   118         //   ServerSocketChannelImpl, SocketChannelImpl

   119         if (filter == EVFILT_READ) {

   120             result |= Net.POLLIN;

   121         } else if (filter == EVFILT_WRITE) {

   122             result |= Net.POLLOUT;

   123         }

   124 

   125         return result;

   126     }

   127 

   128     int getDescriptor(int index) {

   129         int offset = SIZEOF_KEVENT*index + FD_OFFSET;

   130         /* The ident field is 8 bytes in 64-bit world, however the API wants us

   131          * to return an int. Hence read the 8 bytes but return as an int.

   132          */

   133         if (is64bit) {

   134             long fd = keventArray.getLong(offset);

   135             assert fd <= Integer.MAX_VALUE;

   136             return (int) fd;

   137         } else {

   138             return keventArray.getInt(offset);

   139         }

   140     }

   141 

   142     void setInterest(SelChImpl channel, int events) {

   143         synchronized (updateList) {

   144             // update existing registration

   145             updateList.add(new Update(channel, events));

   146         }

   147     }

   148 

   149     void release(SelChImpl channel) {

   150         synchronized (updateList) {

   151             // flush any pending updates

   152             for (Iterator<Update> it = updateList.iterator(); it.hasNext();) {

   153                 if (it.next().channel == channel) {

   154                     it.remove();

   155                 }

   156             }

   157 

   158             // remove

   159             register0(kq, channel.getFDVal(), 0, 0);

   160         }

   161     }

   162 

   163     void updateRegistrations() {

   164         synchronized (updateList) {

   165             Update u;

   166             while ((u = updateList.poll()) != null) {

   167                 SelChImpl ch = u.channel;

   168                 if (!ch.isOpen())

   169                     continue;

   170 

   171                 register0(kq, ch.getFDVal(), u.events & Net.POLLIN, u.events & Net.POLLOUT);

   172             }

   173         }

   174     }

   175 

   176     void close() throws IOException {

   177         FileDispatcherImpl.closeIntFD(kq);

   178         keventArray.free();

   179     }

   180 

   181     int poll(long timeout) {

   182         updateRegistrations();

   183         return kevent0(kq, keventArrayAddress, NUM_KEVENTS, timeout);

   184     }

   185 

   186     void interrupt() {

   187         interrupt(outgoingInterruptFD);

   188     }

   189 

   190     private native int init();

   191     private static native void initStructSizes();

   192 

   193     private native void register0(int kq, int fd, int read, int write);

   194     private native int kevent0(int kq, long keventAddress, int keventCount,

   195                                long timeout);

   196     private static native void interrupt(int fd);

   197 }