src/solaris/classes/sun/nio/ch/EPollArrayWrapper.java - toolchain/jdk/jdk9_jdk - Git at Google

 /*
  * Copyright (c) 2005, 2009, 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.  Oracle designates this
  * particular file as subject to the "Classpath" exception as provided
  * by Oracle in the LICENSE file that accompanied this code.
  *
  * 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.
  */

 package sun.nio.ch;

 import java.io.IOException;
 import java.util.LinkedList;
 import java.util.HashSet;
 import java.util.Iterator;

 /**
  * Manipulates a native array of epoll_event structs on Linux:
  *
  * typedef union epoll_data {
  *     void *ptr;
  *     int fd;
  *     __uint32_t u32;
  *     __uint64_t u64;
  *  } epoll_data_t;
  *
  * struct epoll_event {
  *     __uint32_t events;
  *     epoll_data_t data;
  * };
  *
  * The system call to wait for I/O events is epoll_wait(2). It populates an
  * array of epoll_event structures that are passed to the call. The data
  * member of the epoll_event structure contains the same data as was set
  * when the file descriptor was registered to epoll via epoll_ctl(2). In
  * this implementation we set data.fd to be the file descriptor that we
  * register. That way, we have the file descriptor available when we
  * process the events.
  *
  * All file descriptors registered with epoll have the POLLHUP and POLLERR
  * events enabled even when registered with an event set of 0. To ensure
  * that epoll_wait doesn't poll an idle file descriptor when the underlying
  * connection is closed or reset then its registration is deleted from
  * epoll (it will be re-added again if the event set is changed)
  */

 class EPollArrayWrapper {
     // EPOLL_EVENTS
     static final int EPOLLIN      = 0x001;

     // opcodes
     static final int EPOLL_CTL_ADD      = 1;
     static final int EPOLL_CTL_DEL      = 2;
     static final int EPOLL_CTL_MOD      = 3;

     // Miscellaneous constants
     static final int SIZE_EPOLLEVENT  = sizeofEPollEvent();
     static final int EVENT_OFFSET     = 0;
     static final int DATA_OFFSET      = offsetofData();
     static final int FD_OFFSET        = DATA_OFFSET;
     static final int NUM_EPOLLEVENTS  = Math.min(fdLimit(), 8192);

     // Base address of the native pollArray
     private final long pollArrayAddress;

     // Set of "idle" channels
     private final HashSet<SelChImpl> idleSet;

     EPollArrayWrapper() {
         // creates the epoll file descriptor
         epfd = epollCreate();

         // the epoll_event array passed to epoll_wait
         int allocationSize = NUM_EPOLLEVENTS * SIZE_EPOLLEVENT;
         pollArray = new AllocatedNativeObject(allocationSize, true);
         pollArrayAddress = pollArray.address();

         for (int i=0; i<NUM_EPOLLEVENTS; i++) {
             putEventOps(i, 0);
             putData(i, 0L);
         }

         // create idle set
         idleSet = new HashSet<SelChImpl>();
     }

     // Used to update file description registrations
     private static class Updator {
         SelChImpl channel;
         int opcode;
         int events;
         Updator(SelChImpl channel, int opcode, int events) {
             this.channel = channel;
             this.opcode = opcode;
             this.events = events;
         }
         Updator(SelChImpl channel, int opcode) {
             this(channel, opcode, 0);
         }
     }

     private LinkedList<Updator> updateList = new LinkedList<Updator>();

     // The epoll_event array for results from epoll_wait
     private AllocatedNativeObject pollArray;

     // The fd of the epoll driver
     final int epfd;

     // The fd of the interrupt line going out
     int outgoingInterruptFD;

     // The fd of the interrupt line coming in
     int incomingInterruptFD;

     // The index of the interrupt FD
     int interruptedIndex;

     // Number of updated pollfd entries
     int updated;

     void initInterrupt(int fd0, int fd1) {
         outgoingInterruptFD = fd1;
         incomingInterruptFD = fd0;
         epollCtl(epfd, EPOLL_CTL_ADD, fd0, EPOLLIN);
     }

     void putEventOps(int i, int event) {
         int offset = SIZE_EPOLLEVENT * i + EVENT_OFFSET;
         pollArray.putInt(offset, event);
     }

     void putData(int i, long value) {
         int offset = SIZE_EPOLLEVENT * i + DATA_OFFSET;
         pollArray.putLong(offset, value);
     }

     void putDescriptor(int i, int fd) {
         int offset = SIZE_EPOLLEVENT * i + FD_OFFSET;
         pollArray.putInt(offset, fd);
     }

     int getEventOps(int i) {
         int offset = SIZE_EPOLLEVENT * i + EVENT_OFFSET;
         return pollArray.getInt(offset);
     }

     int getDescriptor(int i) {
         int offset = SIZE_EPOLLEVENT * i + FD_OFFSET;
         return pollArray.getInt(offset);
     }

     /**
      * Update the events for a given channel.
      */
     void setInterest(SelChImpl channel, int mask) {
         synchronized (updateList) {
             // if the previous pending operation is to add this file descriptor
             // to epoll then update its event set
             if (updateList.size() > 0) {
                 Updator last = updateList.getLast();
                 if (last.channel == channel && last.opcode == EPOLL_CTL_ADD) {
                     last.events = mask;
                     return;
                 }
             }

             // update existing registration
             updateList.add(new Updator(channel, EPOLL_CTL_MOD, mask));
         }
     }

     /**
      * Add a channel's file descriptor to epoll
      */
     void add(SelChImpl channel) {
         synchronized (updateList) {
             updateList.add(new Updator(channel, EPOLL_CTL_ADD));
         }
     }

     /**
      * Remove a channel's file descriptor from epoll
      */
     void release(SelChImpl channel) {
         synchronized (updateList) {
             // flush any pending updates
             for (Iterator<Updator> it = updateList.iterator(); it.hasNext();) {
                 if (it.next().channel == channel) {
                     it.remove();
                 }
             }

             // remove from the idle set (if present)
             idleSet.remove(channel);

             // remove from epoll (if registered)
             epollCtl(epfd, EPOLL_CTL_DEL, channel.getFDVal(), 0);
         }
     }

     /**
      * Close epoll file descriptor and free poll array
      */
     void closeEPollFD() throws IOException {
         FileDispatcherImpl.closeIntFD(epfd);
         pollArray.free();
     }

     int poll(long timeout) throws IOException {
         updateRegistrations();
         updated = epollWait(pollArrayAddress, NUM_EPOLLEVENTS, timeout, epfd);
         for (int i=0; i<updated; i++) {
             if (getDescriptor(i) == incomingInterruptFD) {
                 interruptedIndex = i;
                 interrupted = true;
                 break;
             }
         }
         return updated;
     }

     /**
      * Update the pending registrations.
      */
     void updateRegistrations() {
         synchronized (updateList) {
             Updator u = null;
             while ((u = updateList.poll()) != null) {
                 SelChImpl ch = u.channel;
                 if (!ch.isOpen())
                     continue;

                 // if the events are 0 then file descriptor is put into "idle
                 // set" to prevent it being polled
                 if (u.events == 0) {
                     boolean added = idleSet.add(u.channel);
                     // if added to idle set then remove from epoll if registered
                     if (added && (u.opcode == EPOLL_CTL_MOD))
                         epollCtl(epfd, EPOLL_CTL_DEL, ch.getFDVal(), 0);
                 } else {
                     // events are specified. If file descriptor was in idle set
                     // it must be re-registered (by converting opcode to ADD)
                     boolean idle = false;
                     if (!idleSet.isEmpty())
                         idle = idleSet.remove(u.channel);
                     int opcode = (idle) ? EPOLL_CTL_ADD : u.opcode;
                     epollCtl(epfd, opcode, ch.getFDVal(), u.events);
                 }
             }
         }
     }

     // interrupt support
     boolean interrupted = false;

     public void interrupt() {
         interrupt(outgoingInterruptFD);
     }

     public int interruptedIndex() {
         return interruptedIndex;
     }

     boolean interrupted() {
         return interrupted;
     }

     void clearInterrupted() {
         interrupted = false;
     }

     static {
         init();
     }

     private native int epollCreate();
     private native void epollCtl(int epfd, int opcode, int fd, int events);
     private native int epollWait(long pollAddress, int numfds, long timeout,
                                  int epfd) throws IOException;
     private static native int sizeofEPollEvent();
     private static native int offsetofData();
     private static native int fdLimit();
     private static native void interrupt(int fd);
     private static native void init();
 }
	/*
	* Copyright (c) 2005, 2009, 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. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* 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.
	*/

	package sun.nio.ch;

	import java.io.IOException;
	import java.util.LinkedList;
	import java.util.HashSet;
	import java.util.Iterator;

	/**
	* Manipulates a native array of epoll_event structs on Linux:
	*
	* typedef union epoll_data {
	* void *ptr;
	* int fd;
	* __uint32_t u32;
	* __uint64_t u64;
	* } epoll_data_t;
	*
	* struct epoll_event {
	* __uint32_t events;
	* epoll_data_t data;
	* };
	*
	* The system call to wait for I/O events is epoll_wait(2). It populates an
	* array of epoll_event structures that are passed to the call. The data
	* member of the epoll_event structure contains the same data as was set
	* when the file descriptor was registered to epoll via epoll_ctl(2). In
	* this implementation we set data.fd to be the file descriptor that we
	* register. That way, we have the file descriptor available when we
	* process the events.
	*
	* All file descriptors registered with epoll have the POLLHUP and POLLERR
	* events enabled even when registered with an event set of 0. To ensure
	* that epoll_wait doesn't poll an idle file descriptor when the underlying
	* connection is closed or reset then its registration is deleted from
	* epoll (it will be re-added again if the event set is changed)
	*/

	class EPollArrayWrapper {
	// EPOLL_EVENTS
	static final int EPOLLIN = 0x001;

	// opcodes
	static final int EPOLL_CTL_ADD = 1;
	static final int EPOLL_CTL_DEL = 2;
	static final int EPOLL_CTL_MOD = 3;

	// Miscellaneous constants
	static final int SIZE_EPOLLEVENT = sizeofEPollEvent();
	static final int EVENT_OFFSET = 0;
	static final int DATA_OFFSET = offsetofData();
	static final int FD_OFFSET = DATA_OFFSET;
	static final int NUM_EPOLLEVENTS = Math.min(fdLimit(), 8192);

	// Base address of the native pollArray
	private final long pollArrayAddress;

	// Set of "idle" channels
	private final HashSet<SelChImpl> idleSet;

	EPollArrayWrapper() {
	// creates the epoll file descriptor
	epfd = epollCreate();

	// the epoll_event array passed to epoll_wait
	int allocationSize = NUM_EPOLLEVENTS * SIZE_EPOLLEVENT;
	pollArray = new AllocatedNativeObject(allocationSize, true);
	pollArrayAddress = pollArray.address();

	for (int i=0; i<NUM_EPOLLEVENTS; i++) {
	putEventOps(i, 0);
	putData(i, 0L);
	}

	// create idle set
	idleSet = new HashSet<SelChImpl>();
	}

	// Used to update file description registrations
	private static class Updator {
	SelChImpl channel;
	int opcode;
	int events;
	Updator(SelChImpl channel, int opcode, int events) {
	this.channel = channel;
	this.opcode = opcode;
	this.events = events;
	}
	Updator(SelChImpl channel, int opcode) {
	this(channel, opcode, 0);
	}
	}

	private LinkedList<Updator> updateList = new LinkedList<Updator>();

	// The epoll_event array for results from epoll_wait
	private AllocatedNativeObject pollArray;

	// The fd of the epoll driver
	final int epfd;

	// The fd of the interrupt line going out
	int outgoingInterruptFD;

	// The fd of the interrupt line coming in
	int incomingInterruptFD;

	// The index of the interrupt FD
	int interruptedIndex;

	// Number of updated pollfd entries
	int updated;

	void initInterrupt(int fd0, int fd1) {
	outgoingInterruptFD = fd1;
	incomingInterruptFD = fd0;
	epollCtl(epfd, EPOLL_CTL_ADD, fd0, EPOLLIN);
	}

	void putEventOps(int i, int event) {
	int offset = SIZE_EPOLLEVENT * i + EVENT_OFFSET;
	pollArray.putInt(offset, event);
	}

	void putData(int i, long value) {
	int offset = SIZE_EPOLLEVENT * i + DATA_OFFSET;
	pollArray.putLong(offset, value);
	}

	void putDescriptor(int i, int fd) {
	int offset = SIZE_EPOLLEVENT * i + FD_OFFSET;
	pollArray.putInt(offset, fd);
	}

	int getEventOps(int i) {
	int offset = SIZE_EPOLLEVENT * i + EVENT_OFFSET;
	return pollArray.getInt(offset);
	}

	int getDescriptor(int i) {
	int offset = SIZE_EPOLLEVENT * i + FD_OFFSET;
	return pollArray.getInt(offset);
	}

	/**
	* Update the events for a given channel.
	*/
	void setInterest(SelChImpl channel, int mask) {
	synchronized (updateList) {
	// if the previous pending operation is to add this file descriptor
	// to epoll then update its event set
	if (updateList.size() > 0) {
	Updator last = updateList.getLast();
	if (last.channel == channel && last.opcode == EPOLL_CTL_ADD) {
	last.events = mask;
	return;
	}
	}

	// update existing registration
	updateList.add(new Updator(channel, EPOLL_CTL_MOD, mask));
	}
	}

	/**
	* Add a channel's file descriptor to epoll
	*/
	void add(SelChImpl channel) {
	synchronized (updateList) {
	updateList.add(new Updator(channel, EPOLL_CTL_ADD));
	}
	}

	/**
	* Remove a channel's file descriptor from epoll
	*/
	void release(SelChImpl channel) {
	synchronized (updateList) {
	// flush any pending updates
	for (Iterator<Updator> it = updateList.iterator(); it.hasNext();) {
	if (it.next().channel == channel) {
	it.remove();
	}
	}

	// remove from the idle set (if present)
	idleSet.remove(channel);

	// remove from epoll (if registered)
	epollCtl(epfd, EPOLL_CTL_DEL, channel.getFDVal(), 0);
	}
	}

	/**
	* Close epoll file descriptor and free poll array
	*/
	void closeEPollFD() throws IOException {
	FileDispatcherImpl.closeIntFD(epfd);
	pollArray.free();
	}

	int poll(long timeout) throws IOException {
	updateRegistrations();
	updated = epollWait(pollArrayAddress, NUM_EPOLLEVENTS, timeout, epfd);
	for (int i=0; i<updated; i++) {
	if (getDescriptor(i) == incomingInterruptFD) {
	interruptedIndex = i;
	interrupted = true;
	break;
	}
	}
	return updated;
	}

	/**
	* Update the pending registrations.
	*/
	void updateRegistrations() {
	synchronized (updateList) {
	Updator u = null;
	while ((u = updateList.poll()) != null) {
	SelChImpl ch = u.channel;
	if (!ch.isOpen())
	continue;

	// if the events are 0 then file descriptor is put into "idle
	// set" to prevent it being polled
	if (u.events == 0) {
	boolean added = idleSet.add(u.channel);
	// if added to idle set then remove from epoll if registered
	if (added && (u.opcode == EPOLL_CTL_MOD))
	epollCtl(epfd, EPOLL_CTL_DEL, ch.getFDVal(), 0);
	} else {
	// events are specified. If file descriptor was in idle set
	// it must be re-registered (by converting opcode to ADD)
	boolean idle = false;
	if (!idleSet.isEmpty())
	idle = idleSet.remove(u.channel);
	int opcode = (idle) ? EPOLL_CTL_ADD : u.opcode;
	epollCtl(epfd, opcode, ch.getFDVal(), u.events);
	}
	}
	}
	}

	// interrupt support
	boolean interrupted = false;

	public void interrupt() {
	interrupt(outgoingInterruptFD);
	}

	public int interruptedIndex() {
	return interruptedIndex;
	}

	boolean interrupted() {
	return interrupted;
	}

	void clearInterrupted() {
	interrupted = false;
	}

	static {
	init();
	}

	private native int epollCreate();
	private native void epollCtl(int epfd, int opcode, int fd, int events);
	private native int epollWait(long pollAddress, int numfds, long timeout,
	int epfd) throws IOException;
	private static native int sizeofEPollEvent();
	private static native int offsetofData();
	private static native int fdLimit();
	private static native void interrupt(int fd);
	private static native void init();
	}