// AbstractInterruptibleChannel synchronizes invocations of this method
// using AbstractInterruptibleChannel.closeLock, and also ensures that this
// method is only ever invoked once. Before we get to this method, isOpen
// (which is volatile) will have been set to false.
//
protected void implCloseSelectableChannel() throws IOException {
synchronized (stateLock) {
isInputOpen = false;
isOutputOpen = false;
closeImpl();
// Signal native threads, if needed. If a target thread is not
// currently blocked in an I/O operation then no harm is done since
// the signal handler doesn't actually do anything.
//
if (readerThread != 0) NativeThread.signal(readerThread);
if (writerThread != 0) NativeThread.signal(writerThread);
// If this channel is not registered then it's safe to close the fd
// immediately since we know at this point that no thread is
// blocked in an I/O operation upon the channel and, since the
// channel is marked closed, no thread will start another such
// operation. If this channel is registered then we don't close
// the fd since it might be in use by a selector. In that case
// closing this channel caused its keys to be cancelled, so the
// last selector to deregister a key for this channel will invoke
// kill() to close the fd.
//
if (!isRegistered()) kill();
}
}
protected void implCloseSelectableChannel() throws IOException {
synchronized (stateLock) {
if (state != ST_KILLED) nd.preClose(fd);
ResourceManager.afterUdpClose();
// if member of mulitcast group then invalidate all keys
if (registry != null) registry.invalidateAll();
long th;
if ((th = readerThread) != 0) NativeThread.signal(th);
if ((th = writerThread) != 0) NativeThread.signal(th);
if (!isRegistered()) kill();
}
}
public long write0(ByteBuffer[] bufs) throws IOException {
if (bufs == null) throw new NullPointerException();
synchronized (writeLock) {
ensureWriteOpen();
long n = 0;
try {
begin();
synchronized (stateLock) {
if (!isOpen()) return 0;
writerThread = NativeThread.current();
}
for (; ; ) {
n = Net.write(fd, bufs);
if ((n == IOStatus.INTERRUPTED) && isOpen()) continue;
return IOStatus.normalize(n);
}
} finally {
writerCleanup();
end((n > 0) || (n == IOStatus.UNAVAILABLE));
synchronized (stateLock) {
if ((n <= 0) && (!isOutputOpen)) throw new AsynchronousCloseException();
}
assert IOStatus.check(n);
}
}
}
private long read0(ByteBuffer[] bufs) throws IOException {
if (bufs == null) throw new NullPointerException();
synchronized (readLock) {
if (!ensureReadOpen()) return -1;
long n = 0;
try {
begin();
synchronized (stateLock) {
if (!isOpen()) return 0;
readerThread = NativeThread.current();
}
for (; ; ) {
n = Net.read(fd, bufs);
if ((n == IOStatus.INTERRUPTED) && isOpen()) continue;
return IOStatus.normalize(n);
}
} finally {
readerCleanup();
end(n > 0 || (n == IOStatus.UNAVAILABLE));
synchronized (stateLock) {
if ((n <= 0) && (!isInputOpen)) return IOStatus.EOF;
}
assert IOStatus.check(n);
}
}
}
public boolean connect(SocketAddress sa) throws IOException {
int trafficClass = 0; // ## Pick up from options
int localPort = 0;
synchronized (readLock) {
synchronized (writeLock) {
ensureOpenAndUnconnected();
InetSocketAddress isa = Net.checkAddress(sa);
SecurityManager sm = System.getSecurityManager();
if (sm != null) sm.checkConnect(isa.getAddress().getHostAddress(), isa.getPort());
synchronized (blockingLock()) {
int n = 0;
try {
try {
begin();
synchronized (stateLock) {
if (!isOpen()) {
return false;
}
readerThread = NativeThread.current();
}
for (; ; ) {
InetAddress ia = isa.getAddress();
if (ia.isAnyLocalAddress()) ia = InetAddress.getLocalHost();
n = connectImpl(ia, isa.getPort(), trafficClass);
if ((n == IOStatus.INTERRUPTED) && isOpen()) continue;
break;
}
} finally {
readerCleanup();
end((n > 0) || (n == IOStatus.UNAVAILABLE));
assert IOStatus.check(n);
}
} catch (IOException x) {
// If an exception was thrown, close the channel after
// invoking end() so as to avoid bogus
// AsynchronousCloseExceptions
close();
throw x;
}
synchronized (stateLock) {
remoteAddress = isa;
if (n > 0) {
// Connection succeeded; disallow further
// invocation
state = ST_CONNECTED;
return true;
}
// If nonblocking and no exception then connection
// pending; disallow another invocation
if (!isBlocking()) state = ST_PENDING;
else assert false;
}
}
return false;
}
}
}
public void shutdownOutput() throws IOException {
synchronized (stateLock) {
if (!isOpen()) throw new ClosedChannelException();
isOutputOpen = false;
shutdown(fd, SHUT_WR);
if (writerThread != 0) NativeThread.signal(writerThread);
}
}
public int send(ByteBuffer src, SocketAddress target) throws IOException {
if (src == null) throw new NullPointerException();
synchronized (writeLock) {
ensureOpen();
InetSocketAddress isa = Net.checkAddress(target);
InetAddress ia = isa.getAddress();
if (ia == null) throw new IOException("Target address not resolved");
synchronized (stateLock) {
if (!isConnected()) {
if (target == null) throw new NullPointerException();
SecurityManager sm = System.getSecurityManager();
if (sm != null) {
if (ia.isMulticastAddress()) {
sm.checkMulticast(ia);
} else {
sm.checkConnect(ia.getHostAddress(), isa.getPort());
}
}
} else { // Connected case; Check address then write
if (!target.equals(remoteAddress)) {
throw new IllegalArgumentException("Connected address not equal to target address");
}
return write(src);
}
}
int n = 0;
try {
begin();
if (!isOpen()) return 0;
writerThread = NativeThread.current();
do {
n = send(fd, src, isa);
} while ((n == IOStatus.INTERRUPTED) && isOpen());
synchronized (stateLock) {
if (isOpen() && (localAddress == null)) {
localAddress = Net.localAddress(fd);
}
}
return IOStatus.normalize(n);
} finally {
writerThread = 0;
end((n > 0) || (n == IOStatus.UNAVAILABLE));
assert IOStatus.check(n);
}
}
}
public SocketAddress receive(ByteBuffer dst) throws IOException {
if (dst.isReadOnly()) throw new IllegalArgumentException("Read-only buffer");
if (dst == null) throw new NullPointerException();
synchronized (readLock) {
ensureOpen();
// Socket was not bound before attempting receive
if (localAddress() == null) bind(null);
int n = 0;
ByteBuffer bb = null;
try {
begin();
if (!isOpen()) return null;
SecurityManager security = System.getSecurityManager();
readerThread = NativeThread.current();
if (isConnected() || (security == null)) {
do {
n = receive(fd, dst);
} while ((n == IOStatus.INTERRUPTED) && isOpen());
if (n == IOStatus.UNAVAILABLE) return null;
} else {
bb = Util.getTemporaryDirectBuffer(dst.remaining());
for (; ; ) {
do {
n = receive(fd, bb);
} while ((n == IOStatus.INTERRUPTED) && isOpen());
if (n == IOStatus.UNAVAILABLE) return null;
InetSocketAddress isa = (InetSocketAddress) sender;
try {
security.checkAccept(isa.getAddress().getHostAddress(), isa.getPort());
} catch (SecurityException se) {
// Ignore packet
bb.clear();
n = 0;
continue;
}
bb.flip();
dst.put(bb);
break;
}
}
return sender;
} finally {
if (bb != null) Util.releaseTemporaryDirectBuffer(bb);
readerThread = 0;
end((n > 0) || (n == IOStatus.UNAVAILABLE));
assert IOStatus.check(n);
}
}
}
// package-private
int poll(int events, long timeout) throws IOException {
assert Thread.holdsLock(blockingLock()) && !isBlocking();
synchronized (readLock) {
int n = 0;
try {
begin();
synchronized (stateLock) {
if (!isOpen()) return 0;
readerThread = NativeThread.current();
}
n = Net.poll(fd, events, timeout);
} finally {
readerThread = 0;
end(n > 0);
}
return n;
}
}
public int write(ByteBuffer buf) throws IOException {
if (buf == null) throw new NullPointerException();
synchronized (writeLock) {
synchronized (stateLock) {
ensureOpen();
if (!isConnected()) throw new NotYetConnectedException();
}
int n = 0;
try {
begin();
if (!isOpen()) return 0;
writerThread = NativeThread.current();
do {
n = IOUtil.write(fd, buf, -1, nd);
} while ((n == IOStatus.INTERRUPTED) && isOpen());
return IOStatus.normalize(n);
} finally {
writerThread = 0;
end((n > 0) || (n == IOStatus.UNAVAILABLE));
assert IOStatus.check(n);
}
}
}
public long write(ByteBuffer[] srcs, int offset, int length) throws IOException {
if ((offset < 0) || (length < 0) || (offset > srcs.length - length))
throw new IndexOutOfBoundsException();
synchronized (writeLock) {
synchronized (stateLock) {
ensureOpen();
if (!isConnected()) throw new NotYetConnectedException();
}
long n = 0;
try {
begin();
if (!isOpen()) return 0;
writerThread = NativeThread.current();
do {
n = IOUtil.write(fd, srcs, offset, length, nd);
} while ((n == IOStatus.INTERRUPTED) && isOpen());
return IOStatus.normalize(n);
} finally {
writerThread = 0;
end((n > 0) || (n == IOStatus.UNAVAILABLE));
assert IOStatus.check(n);
}
}
}
public boolean finishConnect() throws IOException {
synchronized (readLock) {
synchronized (writeLock) {
synchronized (stateLock) {
if (!isOpen()) throw new ClosedChannelException();
if (state == ST_CONNECTED) return true;
if (state != ST_PENDING) throw new NoConnectionPendingException();
}
int n = 0;
try {
try {
begin();
synchronized (blockingLock()) {
synchronized (stateLock) {
if (!isOpen()) {
return false;
}
readerThread = NativeThread.current();
}
if (!isBlocking()) {
for (; ; ) {
n = checkConnect(fd, false, readyToConnect);
if ((n == IOStatus.INTERRUPTED) && isOpen()) continue;
break;
}
} else {
for (; ; ) {
n = checkConnect(fd, true, readyToConnect);
if (n == 0) {
// Loop in case of
// spurious notifications
continue;
}
if ((n == IOStatus.INTERRUPTED) && isOpen()) continue;
break;
}
}
}
} finally {
synchronized (stateLock) {
readerThread = 0;
if (state == ST_KILLPENDING) {
kill();
// poll()/getsockopt() does not report
// error (throws exception, with n = 0)
// on Linux platform after dup2 and
// signal-wakeup. Force n to 0 so the
// end() can throw appropriate exception
n = 0;
}
}
end((n > 0) || (n == IOStatus.UNAVAILABLE));
assert IOStatus.check(n);
}
} catch (IOException x) {
// If an exception was thrown, close the channel after
// invoking end() so as to avoid bogus
// AsynchronousCloseExceptions
close();
throw x;
}
if (n > 0) {
synchronized (stateLock) {
state = ST_CONNECTED;
}
return true;
}
return false;
}
}
}
public int read(ByteBuffer buf) throws IOException {
if (buf == null) throw new NullPointerException();
synchronized (readLock) {
if (!ensureReadOpen()) return -1;
int n = 0;
try {
// Set up the interruption machinery; see
// AbstractInterruptibleChannel for details
//
begin();
synchronized (stateLock) {
if (!isOpen()) {
// Either the current thread is already interrupted, so
// begin() closed the channel, or another thread closed the
// channel since we checked it a few bytecodes ago. In
// either case the value returned here is irrelevant since
// the invocation of end() in the finally block will throw
// an appropriate exception.
//
return 0;
}
// Save this thread so that it can be signalled on those
// platforms that require it
//
readerThread = NativeThread.current();
}
// Between the previous test of isOpen() and the return of the
// IOUtil.read invocation below, this channel might be closed
// or this thread might be interrupted. We rely upon the
// implicit synchronization point in the kernel read() call to
// make sure that the right thing happens. In either case the
// implCloseSelectableChannel method is ultimately invoked in
// some other thread, so there are three possibilities:
//
// - implCloseSelectableChannel() invokes nd.preClose()
// before this thread invokes read(), in which case the
// read returns immediately with either EOF or an error,
// the latter of which will cause an IOException to be
// thrown.
//
// - implCloseSelectableChannel() invokes nd.preClose() after
// this thread is blocked in read(). On some operating
// systems (e.g., Solaris and Windows) this causes the read
// to return immediately with either EOF or an error
// indication.
//
// - implCloseSelectableChannel() invokes nd.preClose() after
// this thread is blocked in read() but the operating
// system (e.g., Linux) doesn't support preemptive close,
// so implCloseSelectableChannel() proceeds to signal this
// thread, thereby causing the read to return immediately
// with IOStatus.INTERRUPTED.
//
// In all three cases the invocation of end() in the finally
// clause will notice that the channel has been closed and
// throw an appropriate exception (AsynchronousCloseException
// or ClosedByInterruptException) if necessary.
//
// *There is A fourth possibility. implCloseSelectableChannel()
// invokes nd.preClose(), signals reader/writer thred and quickly
// moves on to nd.close() in kill(), which does a real close.
// Then a third thread accepts a new connection, opens file or
// whatever that causes the released "fd" to be recycled. All
// above happens just between our last isOpen() check and the
// next kernel read reached, with the recycled "fd". The solution
// is to postpone the real kill() if there is a reader or/and
// writer thread(s) over there "waiting", leave the cleanup/kill
// to the reader or writer thread. (the preClose() still happens
// so the connection gets cut off as usual).
//
// For socket channels there is the additional wrinkle that
// asynchronous shutdown works much like asynchronous close,
// except that the channel is shutdown rather than completely
// closed. This is analogous to the first two cases above,
// except that the shutdown operation plays the role of
// nd.preClose().
for (; ; ) {
n = Net.read(fd, buf);
if ((n == IOStatus.INTERRUPTED) && isOpen()) {
// The system call was interrupted but the channel
// is still open, so retry
continue;
}
return IOStatus.normalize(n);
}
} finally {
readerCleanup(); // Clear reader thread
// The end method, which is defined in our superclass
// AbstractInterruptibleChannel, resets the interruption
// machinery. If its argument is true then it returns
// normally; otherwise it checks the interrupt and open state
// of this channel and throws an appropriate exception if
// necessary.
//
// So, if we actually managed to do any I/O in the above try
// block then we pass true to the end method. We also pass
// true if the channel was in non-blocking mode when the I/O
// operation was initiated but no data could be transferred;
// this prevents spurious exceptions from being thrown in the
// rare event that a channel is closed or a thread is
// interrupted at the exact moment that a non-blocking I/O
// request is made.
//
end(n > 0 || (n == IOStatus.UNAVAILABLE));
// Extra case for socket channels: Asynchronous shutdown
//
synchronized (stateLock) {
if ((n <= 0) && (!isInputOpen)) return IOStatus.EOF;
}
assert IOStatus.check(n);
}
}
}