8203059: (so) Closing a socket channel registered with Selector and with SO_LINGER set to 0 does not reset connection

Reviewed-by: chegar

src/java.base/share/classes/sun/nio/ch/SocketChannelImpl.java

@@ -867,11 +867,22 @@ class SocketChannelImpl
         // set state to ST_KILLPENDING
         synchronized (stateLock) {
             assert state == ST_CLOSING;
-            // if connected, and the channel is registered with a Selector, we
-            // shutdown the output so that the peer reads EOF
+            // if connected and the channel is registered with a Selector then
+            // shutdown the output if possible so that the peer reads EOF. If
+            // SO_LINGER is enabled and set to a non-zero value then it needs to
+            // be disabled so that the Selector does not wait when it closes
+            // the socket.
             if (connected && isRegistered()) {
                 try {
-                    Net.shutdown(fd, Net.SHUT_WR);
+                    SocketOption<Integer> opt = StandardSocketOptions.SO_LINGER;
+                    int interval = (int) Net.getSocketOption(fd, Net.UNSPEC, opt);
+                    if (interval != 0) {
+                        if (interval > 0) {
+                            // disable SO_LINGER
+                            Net.setSocketOption(fd, Net.UNSPEC, opt, -1);
+                        }
+                        Net.shutdown(fd, Net.SHUT_WR);
+                    }
                 } catch (IOException ignore) { }
             }
             state = ST_KILLPENDING;

test/jdk/java/nio/channels/SocketChannel/LingerOnClose.java

@@ -0,0 +1,119 @@
+/*
+ * Copyright (c) 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.
+ *
+ * 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 8203059
+ * @summary Test SocketChannel.close with SO_LINGER enabled
+ */
+
+import java.io.IOException;
+import java.net.InetAddress;
+import java.net.InetSocketAddress;
+import java.net.StandardSocketOptions;
+import java.nio.ByteBuffer;
+import java.nio.channels.SelectionKey;
+import java.nio.channels.Selector;
+import java.nio.channels.ServerSocketChannel;
+import java.nio.channels.SocketChannel;
+
+public class LingerOnClose {
+
+    private enum TestMode {
+        BLOCKING,
+        NON_BLOCKING,
+        NON_BLOCKING_AND_REGISTERED;
+    }
+
+    public static void main(String[] args) throws IOException {
+        // blocking mode
+        test(TestMode.BLOCKING, -1);
+        test(TestMode.BLOCKING, 0);
+        test(TestMode.BLOCKING, 1);
+
+        // non-blocking mode
+        test(TestMode.NON_BLOCKING, -1);
+        test(TestMode.NON_BLOCKING, 0);
+        test(TestMode.NON_BLOCKING, 1);
+
+        // non-blocking mode, close while registered with Selector
+        test(TestMode.NON_BLOCKING_AND_REGISTERED, -1);
+        test(TestMode.NON_BLOCKING_AND_REGISTERED, 0);
+        test(TestMode.NON_BLOCKING_AND_REGISTERED, 1);
+    }
+
+    /**
+     * Test closing a SocketChannel with SO_LINGER set to the given linger
+     * interval. If the linger interval is 0, it checks that the peer observes
+     * a connection reset (TCP RST).
+     */
+    static void test(TestMode mode, int interval) throws IOException {
+        SocketChannel sc = null;
+        SocketChannel peer = null;
+        Selector sel = null;
+
+        try (ServerSocketChannel ssc = ServerSocketChannel.open()) {
+            ssc.bind(new InetSocketAddress(InetAddress.getLocalHost(), 0));
+
+            // establish loopback connection
+            sc = SocketChannel.open(ssc.getLocalAddress());
+            peer = ssc.accept();
+
+            // configured blocking mode and register with Selector if needed
+            if (mode != TestMode.BLOCKING)
+                sc.configureBlocking(false);
+            if (mode == TestMode.NON_BLOCKING_AND_REGISTERED) {
+                sel = Selector.open();
+                sc.register(sel, SelectionKey.OP_READ);
+                sel.selectNow();
+            }
+
+            // enable or disable SO_LINGER
+            sc.setOption(StandardSocketOptions.SO_LINGER, interval);
+
+            // close channel and flush Selector if needed
+            sc.close();
+            if (mode == TestMode.NON_BLOCKING_AND_REGISTERED)
+                sel.selectNow();
+
+            // read other end of connection, expect EOF or RST
+            ByteBuffer bb = ByteBuffer.allocate(100);
+            try {
+                int n = peer.read(bb);
+                if (interval == 0) {
+                    throw new RuntimeException("RST expected");
+                } else if (n != -1) {
+                    throw new RuntimeException("EOF expected");
+                }
+            } catch (IOException ioe) {
+                if (interval != 0) {
+                    // exception not expected
+                    throw ioe;
+                }
+            }
+        } finally {
+            if (sc != null) sc.close();
+            if (peer != null) peer.close();
+            if (sel != null) sel.close();
+        }
+    }
+}