Hang in PreClose method during dup2 system call

During fcntl, dup2 system calls if read/write happens then PreClose method gets hang. This issue is not seen if we Signal/Kill the thread first and then call the preClose method.

Signed-off-by: Shruthi.Shruthi1 <Shruthi.Shruthi1@ibm.com>

closed/src/java.base/unix/classes/sun/nio/ch/SourceChannelImpl.java

@@ -0,0 +1,301 @@
+/*
+ * Copyright (c) 2000, 2018, 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.
+ */
+
+/*
+ * ===========================================================================
+ * (c) Copyright IBM Corp. 2022, 2022 All Rights Reserved
+ * ===========================================================================
+ */
+
+package sun.nio.ch;
+
+import java.io.FileDescriptor;
+import java.io.IOException;
+import java.nio.ByteBuffer;
+import java.nio.channels.AsynchronousCloseException;
+import java.nio.channels.ClosedChannelException;
+import java.nio.channels.NotYetConnectedException;
+import java.nio.channels.Pipe;
+import java.nio.channels.SelectionKey;
+import java.nio.channels.spi.SelectorProvider;
+import java.util.Objects;
+import java.util.concurrent.locks.ReentrantLock;
+
+class SourceChannelImpl
+ extends Pipe.SourceChannel
+ implements SelChImpl
+{
+ // Used to make native read and write calls
+ private static final NativeDispatcher nd = new FileDispatcherImpl();
+
+ // The file descriptor associated with this channel
+ private final FileDescriptor fd;
+ private final int fdVal;
+
+ // Lock held by current reading thread
+ private final ReentrantLock readLock = new ReentrantLock();
+
+ // Lock held by any thread that modifies the state fields declared below
+ // DO NOT invoke a blocking I/O operation while holding this lock!
+ private final Object stateLock = new Object();
+
+ // -- The following fields are protected by stateLock
+
+ // Channel state
+ private static final int ST_INUSE = 0;
+ private static final int ST_CLOSING = 1;
+ private static final int ST_KILLPENDING = 2;
+ private static final int ST_KILLED = 3;
+ private int state;
+
+ // ID of native thread doing read, for signalling
+ private long thread;
+
+ // -- End of fields protected by stateLock
+
+
+ public FileDescriptor getFD() {
+ return fd;
+ }
+
+ public int getFDVal() {
+ return fdVal;
+ }
+
+ SourceChannelImpl(SelectorProvider sp, FileDescriptor fd) {
+ super(sp);
+ this.fd = fd;
+ this.fdVal = IOUtil.fdVal(fd);
+ }
+
+ /**
+ * Invoked by implCloseChannel to close the channel.
+ */
+ @Override
+ protected void implCloseSelectableChannel() throws IOException {
+ assert !isOpen();
+
+ boolean interrupted = false;
+ boolean blocking;
+
+ // set state to ST_CLOSING
+ synchronized (stateLock) {
+ assert state < ST_CLOSING;
+ state = ST_CLOSING;
+ blocking = isBlocking();
+ }
+
+ // wait for any outstanding read to complete
+ if (blocking) {
+ synchronized (stateLock) {
+ assert state == ST_CLOSING;
+ long th = thread;
+ if (th != 0) {
+ NativeThread.signal(th);
+ nd.preClose(fd);
+
+ // wait for read operation to end
+ while (thread != 0) {
+ try {
+ stateLock.wait();
+ } catch (InterruptedException e) {
+ interrupted = true;
+ }
+ }
+ }
+ }
+ } else {
+ // non-blocking mode: wait for read to complete
+ readLock.lock();
+ readLock.unlock();
+ }
+
+ // set state to ST_KILLPENDING
+ synchronized (stateLock) {
+ assert state == ST_CLOSING;
+ state = ST_KILLPENDING;
+ }
+
+ // close socket if not registered with Selector
+ if (!isRegistered())
+ kill();
+
+ // restore interrupt status
+ if (interrupted)
+ Thread.currentThread().interrupt();
+ }
+
+ @Override
+ public void kill() throws IOException {
+ synchronized (stateLock) {
+ assert thread == 0;
+ if (state == ST_KILLPENDING) {
+ state = ST_KILLED;
+ nd.close(fd);
+ }
+ }
+ }
+
+ @Override
+ protected void implConfigureBlocking(boolean block) throws IOException {
+ readLock.lock();
+ try {
+ synchronized (stateLock) {
+ IOUtil.configureBlocking(fd, block);
+ }
+ } finally {
+ readLock.unlock();
+ }
+ }
+
+ public boolean translateReadyOps(int ops, int initialOps, SelectionKeyImpl ski) {
+ int intOps = ski.nioInterestOps();
+ int oldOps = ski.nioReadyOps();
+ int newOps = initialOps;
+
+ if ((ops & Net.POLLNVAL) != 0)
+ throw new Error("POLLNVAL detected");
+
+ if ((ops & (Net.POLLERR | Net.POLLHUP)) != 0) {
+ newOps = intOps;
+ ski.nioReadyOps(newOps);
+ return (newOps & ~oldOps) != 0;
+ }
+
+ if (((ops & Net.POLLIN) != 0) &&
+ ((intOps & SelectionKey.OP_READ) != 0))
+ newOps |= SelectionKey.OP_READ;
+
+ ski.nioReadyOps(newOps);
+ return (newOps & ~oldOps) != 0;
+ }
+
+ public boolean translateAndUpdateReadyOps(int ops, SelectionKeyImpl ski) {
+ return translateReadyOps(ops, ski.nioReadyOps(), ski);
+ }
+
+ public boolean translateAndSetReadyOps(int ops, SelectionKeyImpl ski) {
+ return translateReadyOps(ops, 0, ski);
+ }
+
+ public int translateInterestOps(int ops) {
+ int newOps = 0;
+ if (ops == SelectionKey.OP_READ)
+ newOps |= Net.POLLIN;
+ return newOps;
+ }
+
+ /**
+ * Marks the beginning of a read operation that might block.
+ *
+ * @throws ClosedChannelException if the channel is closed
+ * @throws NotYetConnectedException if the channel is not yet connected
+ */
+ private void beginRead(boolean blocking) throws ClosedChannelException {
+ if (blocking) {
+ // set hook for Thread.interrupt
+ begin();
+ }
+ synchronized (stateLock) {
+ if (!isOpen())
+ throw new ClosedChannelException();
+ if (blocking)
+ thread = NativeThread.current();
+ }
+ }
+
+ /**
+ * Marks the end of a read operation that may have blocked.
+ *
+ * @throws AsynchronousCloseException if the channel was closed due to this
+ * thread being interrupted on a blocking read operation.
+ */
+ private void endRead(boolean blocking, boolean completed)
+ throws AsynchronousCloseException
+ {
+ if (blocking) {
+ synchronized (stateLock) {
+ thread = 0;
+ // notify any thread waiting in implCloseSelectableChannel
+ if (state == ST_CLOSING) {
+ stateLock.notifyAll();
+ }
+ }
+ // remove hook for Thread.interrupt
+ end(completed);
+ }
+ }
+
+ @Override
+ public int read(ByteBuffer dst) throws IOException {
+ Objects.requireNonNull(dst);
+
+ readLock.lock();
+ try {
+ boolean blocking = isBlocking();
+ int n = 0;
+ try {
+ beginRead(blocking);
+ do {
+ n = IOUtil.read(fd, dst, -1, nd);
+ } while ((n == IOStatus.INTERRUPTED) && isOpen());
+ } finally {
+ endRead(blocking, n > 0);
+ assert IOStatus.check(n);
+ }
+ return IOStatus.normalize(n);
+ } finally {
+ readLock.unlock();
+ }
+ }
+
+ @Override
+ public long read(ByteBuffer[] dsts, int offset, int length) throws IOException {
+ Objects.checkFromIndexSize(offset, length, dsts.length);
+
+ readLock.lock();
+ try {
+ boolean blocking = isBlocking();
+ long n = 0;
+ try {
+ beginRead(blocking);
+ do {
+ n = IOUtil.read(fd, dsts, offset, length, nd);
+ } while ((n == IOStatus.INTERRUPTED) && isOpen());
+ } finally {
+ endRead(blocking, n > 0);
+ assert IOStatus.check(n);
+ }
+ return IOStatus.normalize(n);
+ } finally {
+ readLock.unlock();
+ }
+ }
+
+ @Override
+ public long read(ByteBuffer[] dsts) throws IOException {
+ return read(dsts, 0, dsts.length);
+ }
+}