| /* |
| * Copyright (c) 2005, 2013, 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.security.AccessController; |
| import java.util.BitSet; |
| import java.util.HashMap; |
| import java.util.Map; |
| import sun.security.action.GetIntegerAction; |
| |
| /** |
| * 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. |
| */ |
| |
| class EPollArrayWrapper { |
| // EPOLL_EVENTS |
| private static final int EPOLLIN = 0x001; |
| |
| // opcodes |
| private static final int EPOLL_CTL_ADD = 1; |
| private static final int EPOLL_CTL_DEL = 2; |
| private static final int EPOLL_CTL_MOD = 3; |
| |
| // Miscellaneous constants |
| private static final int SIZE_EPOLLEVENT = sizeofEPollEvent(); |
| private static final int EVENT_OFFSET = 0; |
| private static final int DATA_OFFSET = offsetofData(); |
| private static final int FD_OFFSET = DATA_OFFSET; |
| private static final int OPEN_MAX = IOUtil.fdLimit(); |
| private static final int NUM_EPOLLEVENTS = Math.min(OPEN_MAX, 8192); |
| |
| // Special value to indicate that an update should be ignored |
| private static final byte KILLED = (byte)-1; |
| |
| // Initial size of arrays for fd registration changes |
| private static final int INITIAL_PENDING_UPDATE_SIZE = 64; |
| |
| // maximum size of updatesLow |
| private static final int MAX_UPDATE_ARRAY_SIZE = AccessController.doPrivileged( |
| new GetIntegerAction("sun.nio.ch.maxUpdateArraySize", Math.min(OPEN_MAX, 64*1024))); |
| |
| // The fd of the epoll driver |
| private final int epfd; |
| |
| // The epoll_event array for results from epoll_wait |
| private final AllocatedNativeObject pollArray; |
| |
| // Base address of the epoll_event array |
| private final long pollArrayAddress; |
| |
| // The fd of the interrupt line going out |
| private int outgoingInterruptFD; |
| |
| // The fd of the interrupt line coming in |
| private int incomingInterruptFD; |
| |
| // The index of the interrupt FD |
| private int interruptedIndex; |
| |
| // Number of updated pollfd entries |
| int updated; |
| |
| // object to synchronize fd registration changes |
| private final Object updateLock = new Object(); |
| |
| // number of file descriptors with registration changes pending |
| private int updateCount; |
| |
| // file descriptors with registration changes pending |
| private int[] updateDescriptors = new int[INITIAL_PENDING_UPDATE_SIZE]; |
| |
| // events for file descriptors with registration changes pending, indexed |
| // by file descriptor and stored as bytes for efficiency reasons. For |
| // file descriptors higher than MAX_UPDATE_ARRAY_SIZE (unlimited case at |
| // least) then the update is stored in a map. |
| private final byte[] eventsLow = new byte[MAX_UPDATE_ARRAY_SIZE]; |
| private Map<Integer,Byte> eventsHigh; |
| |
| // Used by release and updateRegistrations to track whether a file |
| // descriptor is registered with epoll. |
| private final BitSet registered = new BitSet(); |
| |
| |
| EPollArrayWrapper() throws IOException { |
| // 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(); |
| |
| // eventHigh needed when using file descriptors > 64k |
| if (OPEN_MAX > MAX_UPDATE_ARRAY_SIZE) |
| eventsHigh = new HashMap<>(); |
| } |
| |
| 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 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); |
| } |
| |
| /** |
| * Returns {@code true} if updates for the given key (file |
| * descriptor) are killed. |
| */ |
| private boolean isEventsHighKilled(Integer key) { |
| assert key >= MAX_UPDATE_ARRAY_SIZE; |
| Byte value = eventsHigh.get(key); |
| return (value != null && value == KILLED); |
| } |
| |
| /** |
| * Sets the pending update events for the given file descriptor. This |
| * method has no effect if the update events is already set to KILLED, |
| * unless {@code force} is {@code true}. |
| */ |
| private void setUpdateEvents(int fd, byte events, boolean force) { |
| if (fd < MAX_UPDATE_ARRAY_SIZE) { |
| if ((eventsLow[fd] != KILLED) || force) { |
| eventsLow[fd] = events; |
| } |
| } else { |
| Integer key = Integer.valueOf(fd); |
| if (!isEventsHighKilled(key) || force) { |
| eventsHigh.put(key, Byte.valueOf(events)); |
| } |
| } |
| } |
| |
| /** |
| * Returns the pending update events for the given file descriptor. |
| */ |
| private byte getUpdateEvents(int fd) { |
| if (fd < MAX_UPDATE_ARRAY_SIZE) { |
| return eventsLow[fd]; |
| } else { |
| Byte result = eventsHigh.get(Integer.valueOf(fd)); |
| // result should never be null |
| return result.byteValue(); |
| } |
| } |
| |
| /** |
| * Update the events for a given file descriptor |
| */ |
| void setInterest(int fd, int mask) { |
| synchronized (updateLock) { |
| // record the file descriptor and events |
| int oldCapacity = updateDescriptors.length; |
| if (updateCount == oldCapacity) { |
| int newCapacity = oldCapacity + INITIAL_PENDING_UPDATE_SIZE; |
| int[] newDescriptors = new int[newCapacity]; |
| System.arraycopy(updateDescriptors, 0, newDescriptors, 0, oldCapacity); |
| updateDescriptors = newDescriptors; |
| } |
| updateDescriptors[updateCount++] = fd; |
| |
| // events are stored as bytes for efficiency reasons |
| byte b = (byte)mask; |
| assert (b == mask) && (b != KILLED); |
| setUpdateEvents(fd, b, false); |
| } |
| } |
| |
| /** |
| * Add a file descriptor |
| */ |
| void add(int fd) { |
| // force the initial update events to 0 as it may be KILLED by a |
| // previous registration. |
| synchronized (updateLock) { |
| assert !registered.get(fd); |
| setUpdateEvents(fd, (byte)0, true); |
| } |
| } |
| |
| /** |
| * Remove a file descriptor |
| */ |
| void remove(int fd) { |
| synchronized (updateLock) { |
| // kill pending and future update for this file descriptor |
| setUpdateEvents(fd, KILLED, false); |
| |
| // remove from epoll |
| if (registered.get(fd)) { |
| epollCtl(epfd, EPOLL_CTL_DEL, fd, 0); |
| registered.clear(fd); |
| } |
| } |
| } |
| |
| /** |
| * 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. |
| */ |
| private void updateRegistrations() { |
| synchronized (updateLock) { |
| int j = 0; |
| while (j < updateCount) { |
| int fd = updateDescriptors[j]; |
| short events = getUpdateEvents(fd); |
| boolean isRegistered = registered.get(fd); |
| int opcode = 0; |
| |
| if (events != KILLED) { |
| if (isRegistered) { |
| opcode = (events != 0) ? EPOLL_CTL_MOD : EPOLL_CTL_DEL; |
| } else { |
| opcode = (events != 0) ? EPOLL_CTL_ADD : 0; |
| } |
| if (opcode != 0) { |
| epollCtl(epfd, opcode, fd, events); |
| if (opcode == EPOLL_CTL_ADD) { |
| registered.set(fd); |
| } else if (opcode == EPOLL_CTL_DEL) { |
| registered.clear(fd); |
| } |
| } |
| } |
| j++; |
| } |
| updateCount = 0; |
| } |
| } |
| |
| // interrupt support |
| private boolean interrupted = false; |
| |
| public void interrupt() { |
| interrupt(outgoingInterruptFD); |
| } |
| |
| public int interruptedIndex() { |
| return interruptedIndex; |
| } |
| |
| boolean interrupted() { |
| return interrupted; |
| } |
| |
| void clearInterrupted() { |
| interrupted = false; |
| } |
| |
| 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 void interrupt(int fd); |
| } |