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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).
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25 
26 package sun.nio.ch;
27 
28 import java.nio.channels.spi.AsynchronousChannelProvider;
29 import java.util.concurrent.RejectedExecutionException;
30 import java.io.IOException;
31 import jdk.internal.misc.Unsafe;
32 
33 /**
34  * Provides an AsynchronousChannelGroup implementation based on the Solaris 10
35  * event port framework and also provides direct access to that framework.
36  */
37 
38 class SolarisEventPort
39     extends Port
40 {
41     private static final Unsafe unsafe = Unsafe.getUnsafe();
42     private static final int addressSize = unsafe.addressSize();
43 
dependsArch(int value32, int value64)44     private static int dependsArch(int value32, int value64) {
45         return (addressSize == 4) ? value32 : value64;
46     }
47 
48     /*
49      * typedef struct port_event {
50      *     int             portev_events;
51      *     ushort_t        portev_source;
52      *     ushort_t        portev_pad;
53      *     uintptr_t       portev_object;
54      *     void            *portev_user;
55      * } port_event_t;
56      */
57     static final int SIZEOF_PORT_EVENT  = dependsArch(16, 24);
58     static final int OFFSETOF_EVENTS    = 0;
59     static final int OFFSETOF_SOURCE    = 4;
60     static final int OFFSETOF_OBJECT    = 8;
61 
62     // port sources
63     static final short PORT_SOURCE_USER     = 3;
64     static final short PORT_SOURCE_FD       = 4;
65 
66     // file descriptor to event port.
67     private final int port;
68 
69     // true when port is closed
70     private boolean closed;
71 
SolarisEventPort(AsynchronousChannelProvider provider, ThreadPool pool)72     SolarisEventPort(AsynchronousChannelProvider provider, ThreadPool pool)
73         throws IOException
74     {
75         super(provider, pool);
76 
77         // create event port
78         this.port = port_create();
79     }
80 
start()81     SolarisEventPort start() {
82         startThreads(new EventHandlerTask());
83         return this;
84     }
85 
86     // releass resources
implClose()87     private void implClose() {
88         synchronized (this) {
89             if (closed)
90                 return;
91             closed = true;
92         }
93         port_close(port);
94     }
95 
wakeup()96     private void wakeup() {
97         try {
98             port_send(port, 0);
99         } catch (IOException x) {
100             throw new AssertionError(x);
101         }
102     }
103 
104     @Override
executeOnHandlerTask(Runnable task)105     void executeOnHandlerTask(Runnable task) {
106         synchronized (this) {
107             if (closed)
108                 throw new RejectedExecutionException();
109             offerTask(task);
110             wakeup();
111         }
112     }
113 
114     @Override
shutdownHandlerTasks()115     void shutdownHandlerTasks() {
116        /*
117          * If no tasks are running then just release resources; otherwise
118          * write to the one end of the socketpair to wakeup any polling threads..
119          */
120         int nThreads = threadCount();
121         if (nThreads == 0) {
122             implClose();
123         } else {
124             // send user event to wakeup each thread
125             while (nThreads-- > 0) {
126                 try {
127                     port_send(port, 0);
128                 } catch (IOException x) {
129                     throw new AssertionError(x);
130                 }
131             }
132         }
133     }
134 
135     @Override
startPoll(int fd, int events)136     void startPoll(int fd, int events) {
137         // (re-)associate file descriptor
138         // no need to translate events
139         try {
140             port_associate(port, PORT_SOURCE_FD, fd, events);
141         } catch (IOException x) {
142             throw new AssertionError();     // should not happen
143         }
144     }
145 
146     /*
147      * Task to read a single event from the port and dispatch it to the
148      * channel's onEvent handler.
149      */
150     private class EventHandlerTask implements Runnable {
run()151         public void run() {
152             Invoker.GroupAndInvokeCount myGroupAndInvokeCount =
153                 Invoker.getGroupAndInvokeCount();
154             final boolean isPooledThread = (myGroupAndInvokeCount != null);
155             boolean replaceMe = false;
156             long address = unsafe.allocateMemory(SIZEOF_PORT_EVENT);
157             try {
158                 for (;;) {
159                     // reset invoke count
160                     if (isPooledThread)
161                         myGroupAndInvokeCount.resetInvokeCount();
162 
163                     // wait for I/O completion event
164                     // A error here is fatal (thread will not be replaced)
165                     replaceMe = false;
166                     try {
167                         int n;
168                         do {
169                             n = port_get(port, address);
170                         } while (n == IOStatus.INTERRUPTED);
171                     } catch (IOException x) {
172                         x.printStackTrace();
173                         return;
174                     }
175 
176                     // event source
177                     short source = unsafe.getShort(address + OFFSETOF_SOURCE);
178                     if (source != PORT_SOURCE_FD) {
179                         // user event is trigger to invoke task or shutdown
180                         if (source == PORT_SOURCE_USER) {
181                             Runnable task = pollTask();
182                             if (task == null) {
183                                 // shutdown request
184                                 return;
185                             }
186                             // run task (may throw error/exception)
187                             replaceMe = true;
188                             task.run();
189                         }
190                         // ignore
191                         continue;
192                     }
193 
194                     // pe->portev_object is file descriptor
195                     int fd = (int)unsafe.getAddress(address + OFFSETOF_OBJECT);
196                     // pe->portev_events
197                     int events = unsafe.getInt(address + OFFSETOF_EVENTS);
198 
199                     // lookup channel
200                     PollableChannel ch;
201                     fdToChannelLock.readLock().lock();
202                     try {
203                         ch = fdToChannel.get(fd);
204                     } finally {
205                         fdToChannelLock.readLock().unlock();
206                     }
207 
208                     // notify channel
209                     if (ch != null) {
210                         replaceMe = true;
211                         // no need to translate events
212                         ch.onEvent(events, isPooledThread);
213                     }
214                 }
215             } finally {
216                 // free per-thread resources
217                 unsafe.freeMemory(address);
218                 // last task to exit when shutdown release resources
219                 int remaining = threadExit(this, replaceMe);
220                 if (remaining == 0 && isShutdown())
221                     implClose();
222             }
223         }
224     }
225 
226     /**
227      * Creates an event port
228      */
port_create()229     static native int port_create() throws IOException;
230 
231     /**
232      * Associates specific events of a given object with a port
233      */
port_associate(int port, int source, long object, int events)234     static native boolean port_associate(int port, int source, long object, int events)
235         throws IOException;
236 
237     /**
238      * Removes the association of an object with a port.
239      */
port_dissociate(int port, int source, long object)240     static native boolean port_dissociate(int port, int source, long object)
241         throws IOException;
242 
243     /**
244      * Retrieves a single event from a port
245      */
port_get(int port, long address)246     static native int port_get(int port, long address) throws IOException;
247 
248     /**
249      * Retrieves at most {@code max} events from a port.
250      */
port_getn(int port, long address, int max, long timeout)251     static native int port_getn(int port, long address, int max, long timeout)
252         throws IOException;
253 
254     /**
255      * Sends a user-defined eventto a specified  port.
256      */
port_send(int port, int events)257     static native void port_send(int port, int events) throws IOException;
258 
259     /**
260      * Closes a port.
261      */
port_close(int port)262     static native void port_close(int port);
263 
264 
265     static {
IOUtil.load()266         IOUtil.load();
267     }
268 }
269