7132889: (se) AbstractSelectableChannel.register and configureBlocking not safe from asynchronous close
Reviewed-by: alanb
Contributed-by: Shirish Kuncolienkar <shirishk@linux.vnet.ibm.com>
--- a/jdk/src/share/classes/java/nio/channels/spi/AbstractSelectableChannel.java Mon Aug 20 14:52:12 2012 +0100
+++ b/jdk/src/share/classes/java/nio/channels/spi/AbstractSelectableChannel.java Tue Aug 21 13:42:08 2012 +0100
@@ -90,27 +90,26 @@
// -- Utility methods for the key set --
private void addKey(SelectionKey k) {
- synchronized (keyLock) {
- int i = 0;
- if ((keys != null) && (keyCount < keys.length)) {
- // Find empty element of key array
- for (i = 0; i < keys.length; i++)
- if (keys[i] == null)
- break;
- } else if (keys == null) {
- keys = new SelectionKey[3];
- } else {
- // Grow key array
- int n = keys.length * 2;
- SelectionKey[] ks = new SelectionKey[n];
- for (i = 0; i < keys.length; i++)
- ks[i] = keys[i];
- keys = ks;
- i = keyCount;
- }
- keys[i] = k;
- keyCount++;
+ assert Thread.holdsLock(keyLock);
+ int i = 0;
+ if ((keys != null) && (keyCount < keys.length)) {
+ // Find empty element of key array
+ for (i = 0; i < keys.length; i++)
+ if (keys[i] == null)
+ break;
+ } else if (keys == null) {
+ keys = new SelectionKey[3];
+ } else {
+ // Grow key array
+ int n = keys.length * 2;
+ SelectionKey[] ks = new SelectionKey[n];
+ for (i = 0; i < keys.length; i++)
+ ks[i] = keys[i];
+ keys = ks;
+ i = keyCount;
}
+ keys[i] = k;
+ keyCount++;
}
private SelectionKey findKey(Selector sel) {
@@ -190,11 +189,11 @@
Object att)
throws ClosedChannelException
{
- if (!isOpen())
- throw new ClosedChannelException();
- if ((ops & ~validOps()) != 0)
- throw new IllegalArgumentException();
synchronized (regLock) {
+ if (!isOpen())
+ throw new ClosedChannelException();
+ if ((ops & ~validOps()) != 0)
+ throw new IllegalArgumentException();
if (blocking)
throw new IllegalBlockingModeException();
SelectionKey k = findKey(sel);
@@ -204,8 +203,12 @@
}
if (k == null) {
// New registration
- k = ((AbstractSelector)sel).register(this, ops, att);
- addKey(k);
+ synchronized (keyLock) {
+ if (!isOpen())
+ throw new ClosedChannelException();
+ k = ((AbstractSelector)sel).register(this, ops, att);
+ addKey(k);
+ }
}
return k;
}
@@ -275,9 +278,9 @@
public final SelectableChannel configureBlocking(boolean block)
throws IOException
{
- if (!isOpen())
- throw new ClosedChannelException();
synchronized (regLock) {
+ if (!isOpen())
+ throw new ClosedChannelException();
if (blocking == block)
return this;
if (block && haveValidKeys())
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/test/java/nio/channels/SelectionKey/RacyRegister.java Tue Aug 21 13:42:08 2012 +0100
@@ -0,0 +1,71 @@
+/*
+ * Copyright (c) 2012, 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.
+ *
+ * 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.
+ */
+
+/* @test
+ * @bug 7132889
+ * @summary Test that register does not return a valid SelectionKey when
+ * invoked at around the time that the channel is closed
+ */
+
+import java.nio.channels.*;
+import java.util.concurrent.*;
+import java.util.Random;
+import java.io.IOException;
+
+public class RacyRegister {
+
+ public static void main(String[] args) throws Exception {
+ ExecutorService pool = Executors.newFixedThreadPool(1);
+ try (Selector sel = Selector.open()) {
+ int count = 100;
+ while (count-- > 0) {
+ final SocketChannel sc = SocketChannel.open();
+ sc.configureBlocking(false);
+
+ // close channel asynchronously
+ Future<Void> result = pool.submit(new Callable<Void>() {
+ public Void call() throws IOException {
+ sc.close();
+ return null;
+ }
+ });
+
+ // attempt to register channel with Selector
+ SelectionKey key = null;
+ try {
+ key = sc.register(sel, SelectionKey.OP_READ);
+ } catch (ClosedChannelException ignore) {
+ }
+
+ // ensure close is done
+ result.get();
+
+ // if we have a key then it should be invalid
+ if (key != null && key.isValid())
+ throw new RuntimeException("Key is valid");
+ }
+ } finally {
+ pool.shutdown();
+ }
+ }
+}