/*
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* 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.
*
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package sun.nio.ch;
import java.io.IOException;
import java.util.BitSet;
import java.util.Map;
import java.util.HashMap;
/**
* Manipulates a native array of pollfd structs on Solaris:
*
* typedef struct pollfd {
* int fd;
* short events;
* short revents;
* } pollfd_t;
*
* @author Mike McCloskey
* @since 1.4
*/
class DevPollArrayWrapper {
// Event masks
static final short POLLIN = 0x0001;
static final short POLLPRI = 0x0002;
static final short POLLOUT = 0x0004;
static final short POLLRDNORM = 0x0040;
static final short POLLWRNORM = POLLOUT;
static final short POLLRDBAND = 0x0080;
static final short POLLWRBAND = 0x0100;
static final short POLLNORM = POLLRDNORM;
static final short POLLERR = 0x0008;
static final short POLLHUP = 0x0010;
static final short POLLNVAL = 0x0020;
static final short POLLREMOVE = 0x0800;
static final short POLLCONN = POLLOUT;
// Miscellaneous constants
static final short SIZE_POLLFD = 8;
static final short FD_OFFSET = 0;
static final short EVENT_OFFSET = 4;
static final short REVENT_OFFSET = 6;
// Special value to indicate that an update should be ignored
static final byte IGNORE = (byte)-1;
// Maximum number of open file descriptors
static final int OPEN_MAX = IOUtil.fdLimit();
// Number of pollfd structures to create.
// dpwrite/ioctl(DP_POLL) allows up to OPEN_MAX-1
static final int NUM_POLLFDS = Math.min(OPEN_MAX-1, 8192);
// Initial size of arrays for fd registration changes
private final int INITIAL_PENDING_UPDATE_SIZE = 64;
// maximum size of updatesLow
private final int MAX_UPDATE_ARRAY_SIZE = Math.min(OPEN_MAX, 64*1024);
// The pollfd array for results from devpoll driver
private final AllocatedNativeObject pollArray;
// Base address of the native pollArray
private final long pollArrayAddress;
// The fd of the devpoll driver
private int wfd;
// 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 /dev/poll.
private final BitSet registered = new BitSet();
DevPollArrayWrapper() {
int allocationSize = NUM_POLLFDS * SIZE_POLLFD;
pollArray = new AllocatedNativeObject(allocationSize, true);
pollArrayAddress = pollArray.address();
wfd = init();
if (OPEN_MAX > MAX_UPDATE_ARRAY_SIZE)
eventsHigh = new HashMap<>();
}
void initInterrupt(int fd0, int fd1) {
outgoingInterruptFD = fd1;
incomingInterruptFD = fd0;
register(wfd, fd0, POLLIN);
}
void putReventOps(int i, int revent) {
int offset = SIZE_POLLFD * i + REVENT_OFFSET;
pollArray.putShort(offset, (short)revent);
}
int getEventOps(int i) {
int offset = SIZE_POLLFD * i + EVENT_OFFSET;
return pollArray.getShort(offset);
}
int getReventOps(int i) {
int offset = SIZE_POLLFD * i + REVENT_OFFSET;
return pollArray.getShort(offset);
}
int getDescriptor(int i) {
int offset = SIZE_POLLFD * i + FD_OFFSET;
return pollArray.getInt(offset);
}
private void setUpdateEvents(int fd, byte events) {
if (fd < MAX_UPDATE_ARRAY_SIZE) {
eventsLow[fd] = events;
} else {
eventsHigh.put(Integer.valueOf(fd), Byte.valueOf(events));
}
}
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();
}
}
void setInterest(int fd, int mask) {
synchronized (updateLock) {
// record the file descriptor and events, expanding the
// respective arrays first if necessary.
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 != IGNORE);
setUpdateEvents(fd, b);
}
}
void release(int fd) {
synchronized (updateLock) {
// ignore any pending update for this file descriptor
setUpdateEvents(fd, IGNORE);
// remove from /dev/poll
if (registered.get(fd)) {
register(wfd, fd, POLLREMOVE);
registered.clear(fd);
}
}
}
void closeDevPollFD() throws IOException {
FileDispatcherImpl.closeIntFD(wfd);
pollArray.free();
}
int poll(long timeout) throws IOException {
updateRegistrations();
updated = poll0(pollArrayAddress, NUM_POLLFDS, timeout, wfd);
for (int i=0; i<updated; i++) {
if (getDescriptor(i) == incomingInterruptFD) {
interruptedIndex = i;
interrupted = true;
break;
}
}
return updated;
}
void updateRegistrations() throws IOException {
synchronized (updateLock) {
// Populate pollfd array with updated masks
int j = 0;
int index = 0;
while (j < updateCount) {
int fd = updateDescriptors[j];
short events = getUpdateEvents(fd);
boolean wasRegistered = registered.get(fd);
// events = 0 => POLLREMOVE or do-nothing
if (events != IGNORE) {
if (events == 0) {
if (wasRegistered) {
events = POLLREMOVE;
registered.clear(fd);
} else {
events = IGNORE;
}
} else {
if (!wasRegistered) {
registered.set(fd);
}
}
}
// populate pollfd array with updated event
if (events != IGNORE) {
// insert POLLREMOVE if changing events
if (wasRegistered && events != POLLREMOVE) {
putPollFD(pollArray, index, fd, POLLREMOVE);
index++;
}
putPollFD(pollArray, index, fd, events);
index++;
if (index >= (NUM_POLLFDS-1)) {
registerMultiple(wfd, pollArray.address(), index);
index = 0;
}
// events for this fd now up to date
setUpdateEvents(fd, IGNORE);
}
j++;
}
// write any remaining updates
if (index > 0)
registerMultiple(wfd, pollArray.address(), index);
updateCount = 0;
}
}
private void putPollFD(AllocatedNativeObject array, int index, int fd,
short event)
{
int structIndex = SIZE_POLLFD * index;
array.putInt(structIndex + FD_OFFSET, fd);
array.putShort(structIndex + EVENT_OFFSET, event);
array.putShort(structIndex + REVENT_OFFSET, (short)0);
}
boolean interrupted = false;
public void interrupt() {
interrupt(outgoingInterruptFD);
}
public int interruptedIndex() {
return interruptedIndex;
}
boolean interrupted() {
return interrupted;
}
void clearInterrupted() {
interrupted = false;
}
private native int init();
private native void register(int wfd, int fd, int mask);
private native void registerMultiple(int wfd, long address, int len)
throws IOException;
private native int poll0(long pollAddress, int numfds, long timeout,
int wfd);
private static native void interrupt(int fd);
static {
IOUtil.load();
}
}