1 /*
   2  * Copyright (c) 2012, 2013, 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 package sun.nio.ch;
  27 
  28 import java.io.IOException;
  29 import java.security.AccessController;
  30 import java.util.BitSet;
  31 import java.util.HashMap;
  32 import java.util.Map;
  33 
  34 import sun.misc.Unsafe;
  35 import sun.security.action.GetIntegerAction;
  36 import static sun.nio.ch.SolarisEventPort.*;
  37 
  38 /**
  39  * Manages a Solaris event port and manipulates a native array of pollfd structs
  40  * on Solaris.
  41  */
  42 
  43 class EventPortWrapper {
  44     private static final Unsafe unsafe = Unsafe.getUnsafe();
  45     private static final int addressSize = unsafe.addressSize();
  46 
  47     // Maximum number of open file descriptors
  48     static final int   OPEN_MAX     = IOUtil.fdLimit();
  49 
  50     // Maximum number of events to retrive in one call to port_getn
  51     static final int   POLL_MAX     =  Math.min(OPEN_MAX-1, 1024);
  52 
  53     // initial size of the array to hold pending updates
  54     private final int INITIAL_PENDING_UPDATE_SIZE = 256;
  55 
  56     // maximum size of updateArray
  57     private static final int MAX_UPDATE_ARRAY_SIZE = AccessController.doPrivileged(
  58         new GetIntegerAction("sun.nio.ch.maxUpdateArraySize", Math.min(OPEN_MAX, 64*1024)));
  59 
  60     // special update status to indicate that it should be ignored
  61     private static final byte IGNORE = -1;
  62 
  63     // port file descriptor
  64     private final int pfd;
  65 
  66     // the poll array (populated by port_getn)
  67     private final long pollArrayAddress;
  68     private final AllocatedNativeObject pollArray;
  69 
  70     // required when accessing the update* fields
  71     private final Object updateLock = new Object();
  72 
  73     // the number of pending updates
  74     private int updateCount;
  75 
  76     // queue of file descriptors with updates pending
  77     private int[] updateDescriptors = new int[INITIAL_PENDING_UPDATE_SIZE];
  78 
  79     // events for file descriptors with registration changes pending, indexed
  80     // by file descriptor and stored as bytes for efficiency reasons. For
  81     // file descriptors higher than MAX_UPDATE_ARRAY_SIZE (unlimited case at
  82     // least then the update is stored in a map.
  83     private final byte[] eventsLow = new byte[MAX_UPDATE_ARRAY_SIZE];
  84     private Map<Integer,Byte> eventsHigh;
  85     // Used by release and updateRegistrations to track whether a file
  86     // descriptor is registered with /dev/poll.
  87     private final BitSet registered = new BitSet();
  88 
  89     // bit set to indicate if a file descriptor has been visited when
  90     // processing updates (used to avoid duplicates calls to port_associate)
  91     private BitSet visited = new BitSet();
  92 
  93     EventPortWrapper() throws IOException {
  94         int allocationSize = POLL_MAX * SIZEOF_PORT_EVENT;
  95         pollArray = new AllocatedNativeObject(allocationSize, true);
  96         pollArrayAddress = pollArray.address();
  97         this.pfd = port_create();
  98         if (OPEN_MAX > MAX_UPDATE_ARRAY_SIZE)
  99             eventsHigh = new HashMap<>();
 100     }
 101 
 102     void close() throws IOException {
 103         port_close(pfd);
 104         pollArray.free();
 105     }
 106 
 107     private short getSource(int i) {
 108         int offset = SIZEOF_PORT_EVENT * i + OFFSETOF_SOURCE;
 109         return pollArray.getShort(offset);
 110     }
 111 
 112     int getEventOps(int i) {
 113         int offset = SIZEOF_PORT_EVENT * i + OFFSETOF_EVENTS;
 114         return pollArray.getInt(offset);
 115     }
 116 
 117     int getDescriptor(int i) {
 118         int offset = SIZEOF_PORT_EVENT * i + OFFSETOF_OBJECT;
 119         if (addressSize == 4) {
 120             return pollArray.getInt(offset);
 121         } else {
 122             return (int) pollArray.getLong(offset);
 123         }
 124     }
 125 
 126     private void setDescriptor(int i, int fd) {
 127         int offset = SIZEOF_PORT_EVENT * i + OFFSETOF_OBJECT;
 128         if (addressSize == 4) {
 129             pollArray.putInt(offset, fd);
 130         } else {
 131             pollArray.putLong(offset, fd);
 132         }
 133     }
 134 
 135     private void setUpdate(int fd, byte events) {
 136         if (fd < MAX_UPDATE_ARRAY_SIZE) {
 137             eventsLow[fd] = events;
 138         } else {
 139             eventsHigh.put(Integer.valueOf(fd), Byte.valueOf(events));
 140         }
 141     }
 142 
 143     private byte getUpdate(int fd) {
 144         if (fd < MAX_UPDATE_ARRAY_SIZE) {
 145             return eventsLow[fd];
 146         } else {
 147             Byte result = eventsHigh.get(Integer.valueOf(fd));
 148             // result should never be null
 149             return result.byteValue();
 150         }
 151     }
 152 
 153     int poll(long timeout) throws IOException {
 154         // update registrations prior to poll
 155         synchronized (updateLock) {
 156 
 157             // process newest updates first
 158             int i = updateCount - 1;
 159             while (i >= 0) {
 160                 int fd = updateDescriptors[i];
 161                 if (!visited.get(fd)) {
 162                     short ev = getUpdate(fd);
 163                     if (ev != IGNORE) {
 164                         if (ev == 0) {
 165                             if (registered.get(fd)) {
 166                                 port_dissociate(pfd, PORT_SOURCE_FD, (long)fd);
 167                                 registered.clear(fd);
 168                             }
 169                         } else {
 170                             if (port_associate(pfd, PORT_SOURCE_FD, (long)fd, ev)) {
 171                                 registered.set(fd);
 172                             }
 173                         }
 174 
 175                     }
 176                     visited.set(fd);
 177                 }
 178                 i--;
 179             }
 180             updateCount = 0;
 181         }
 182 
 183         // poll for events
 184         int updated = port_getn(pfd, pollArrayAddress, POLL_MAX, timeout);
 185 
 186         // after polling we need to queue all polled file descriptors as they
 187         // are candidates to register for the next poll.
 188         synchronized (updateLock) {
 189             for (int i=0; i<updated; i++) {
 190                 if (getSource(i) == PORT_SOURCE_USER) {
 191                     interrupted = true;
 192                     setDescriptor(i, -1);
 193                 } else {
 194                     // the default is to re-associate for the next poll
 195                     int fd = getDescriptor(i);
 196                     registered.clear(fd);
 197                     setInterest(fd);
 198                 }
 199             }
 200         }
 201 
 202         return updated;
 203     }
 204 
 205     private void setInterest(int fd) {
 206         assert Thread.holdsLock(updateLock);
 207 
 208         // record the file descriptor and events, expanding the
 209         // respective arrays first if necessary.
 210         int oldCapacity = updateDescriptors.length;
 211         if (updateCount >= oldCapacity) {
 212             int newCapacity = oldCapacity + INITIAL_PENDING_UPDATE_SIZE;
 213             int[] newDescriptors = new int[newCapacity];
 214             System.arraycopy(updateDescriptors, 0, newDescriptors, 0, oldCapacity);
 215             updateDescriptors = newDescriptors;
 216         }
 217         updateDescriptors[updateCount++] = fd;
 218         visited.clear(fd);
 219     }
 220 
 221     void setInterest(int fd, int mask) {
 222         synchronized (updateLock) {
 223             setInterest(fd);
 224             setUpdate(fd, (byte)mask);
 225             assert getUpdate(fd) == mask;
 226         }
 227     }
 228 
 229     void release(int fd) {
 230         synchronized (updateLock) {
 231             if (registered.get(fd)) {
 232                 try {
 233                     port_dissociate(pfd, PORT_SOURCE_FD, (long)fd);
 234                 } catch (IOException ioe) {
 235                     throw new InternalError(ioe);
 236                 }
 237                 registered.clear(fd);
 238             }
 239             setUpdate(fd, IGNORE);
 240         }
 241     }
 242 
 243     // -- wakeup support --
 244 
 245     private boolean interrupted;
 246 
 247     public void interrupt() {
 248         try {
 249             port_send(pfd, 0);
 250         } catch (IOException ioe) {
 251             throw new InternalError(ioe);
 252         }
 253     }
 254 
 255     boolean interrupted() {
 256         return interrupted;
 257     }
 258 
 259     void clearInterrupted() {
 260         interrupted = false;
 261     }
 262 }