From 34cdd7b82b20abc21df29620233647d2f40a386c Mon Sep 17 00:00:00 2001 From: "Shruthi.Shruthi1" Date: Tue, 27 Dec 2022 02:27:59 -0800 Subject: [PATCH] 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 --- .../classes/sun/nio/ch/SourceChannelImpl.java | 301 ++++++++++++++++++ 1 file changed, 301 insertions(+) create mode 100644 closed/src/java.base/unix/classes/sun/nio/ch/SourceChannelImpl.java diff --git a/closed/src/java.base/unix/classes/sun/nio/ch/SourceChannelImpl.java b/closed/src/java.base/unix/classes/sun/nio/ch/SourceChannelImpl.java new file mode 100644 index 00000000000..c8ccf070bbe --- /dev/null +++ b/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); + } +}