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new ddc78157ca [KARAF-2513] Fix log:tail thread leak on SSH disconnect
(#2514)
ddc78157ca is described below
commit ddc78157ca0bcb4afb7a55d10726ed0a32be418d
Author: JB Onofré <[email protected]>
AuthorDate: Sun Apr 5 18:17:48 2026 +0200
[KARAF-2513] Fix log:tail thread leak on SSH disconnect (#2514)
ShellCommand.destroy() was empty, so when an SSH session is closed or
times out while log:tail is running, the command thread stays blocked
on wait() indefinitely. Each reconnect leaks another thread.
Store the Karaf session and command thread as fields and clean them up
in destroy() — close the session and interrupt the thread, mirroring
what ShellFactoryImpl already does for interactive shells.
---
.../org/apache/karaf/shell/ssh/ShellCommand.java | 12 ++-
.../apache/karaf/shell/ssh/ShellCommandTest.java | 109 +++++++++++++++++++++
2 files changed, 119 insertions(+), 2 deletions(-)
diff --git
a/shell/ssh/src/main/java/org/apache/karaf/shell/ssh/ShellCommand.java
b/shell/ssh/src/main/java/org/apache/karaf/shell/ssh/ShellCommand.java
index 1affedb054..39d0adcd19 100644
--- a/shell/ssh/src/main/java/org/apache/karaf/shell/ssh/ShellCommand.java
+++ b/shell/ssh/src/main/java/org/apache/karaf/shell/ssh/ShellCommand.java
@@ -65,6 +65,8 @@ public class ShellCommand implements Command {
private ServerSession serverSession;
private SessionFactory sessionFactory;
private Environment env;
+ private Session session;
+ private Thread commandThread;
public ShellCommand(SessionFactory sessionFactory, String command) {
this.sessionFactory = sessionFactory;
@@ -95,9 +97,10 @@ public class ShellCommand implements Command {
}
public void run() {
+ commandThread = Thread.currentThread();
int exitStatus = 0;
try {
- final Session session = sessionFactory.create(in, new
PrintStream(out), new PrintStream(err));
+ session = sessionFactory.create(in, new PrintStream(out), new
PrintStream(err));
for (Map.Entry<String,String> e : env.getEnv().entrySet()) {
session.put(e.getKey(), e.getValue());
}
@@ -154,7 +157,12 @@ public class ShellCommand implements Command {
@Override
public void destroy(ChannelSession channelSession) throws Exception {
-
+ if (session != null) {
+ session.close();
+ }
+ if (commandThread != null && commandThread != Thread.currentThread()) {
+ commandThread.interrupt();
+ }
}
private void executeScript(String names, Session session) {
diff --git
a/shell/ssh/src/test/java/org/apache/karaf/shell/ssh/ShellCommandTest.java
b/shell/ssh/src/test/java/org/apache/karaf/shell/ssh/ShellCommandTest.java
new file mode 100644
index 0000000000..a6fe221a2b
--- /dev/null
+++ b/shell/ssh/src/test/java/org/apache/karaf/shell/ssh/ShellCommandTest.java
@@ -0,0 +1,109 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.karaf.shell.ssh;
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.InputStream;
+import java.io.PrintStream;
+import java.util.Collections;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+
+import org.apache.karaf.shell.api.console.Session;
+import org.apache.karaf.shell.api.console.SessionFactory;
+import org.apache.sshd.server.Environment;
+import org.apache.sshd.server.ExitCallback;
+import org.apache.sshd.server.channel.ChannelSession;
+import org.apache.sshd.server.session.ServerSession;
+import org.easymock.EasyMock;
+import org.easymock.IAnswer;
+import org.junit.Assert;
+import org.junit.Test;
+
+public class ShellCommandTest {
+
+ @Test
+ public void testDestroyInterruptsBlockingCommand() throws Exception {
+ // Simulate a blocking command (like log:tail) that waits until
interrupted
+ CountDownLatch commandStarted = new CountDownLatch(1);
+ CountDownLatch commandFinished = new CountDownLatch(1);
+
+ Session session = EasyMock.createMock(Session.class);
+ session.put(EasyMock.anyString(), EasyMock.anyObject());
+ EasyMock.expectLastCall().anyTimes();
+
+ // The execute() call blocks until the thread is interrupted
+
EasyMock.expect(session.execute(EasyMock.anyString())).andAnswer((IAnswer<Object>)
() -> {
+ commandStarted.countDown();
+ try {
+ Thread.sleep(60000);
+ } catch (InterruptedException e) {
+ // Expected when destroy() is called
+ }
+ commandFinished.countDown();
+ return null;
+ });
+ session.close();
+ EasyMock.expectLastCall().once();
+
+ SessionFactory sessionFactory =
EasyMock.createMock(SessionFactory.class);
+ EasyMock.expect(sessionFactory.create(
+ EasyMock.anyObject(InputStream.class),
+ EasyMock.anyObject(PrintStream.class),
+ EasyMock.anyObject(PrintStream.class)))
+ .andReturn(session);
+
+ Environment env = EasyMock.createMock(Environment.class);
+ EasyMock.expect(env.getEnv()).andReturn(Collections.emptyMap());
+
+ ExitCallback exitCallback = EasyMock.createMock(ExitCallback.class);
+ exitCallback.onExit(EasyMock.anyInt());
+ EasyMock.expectLastCall().once();
+
+ ChannelSession channelSession =
EasyMock.createMock(ChannelSession.class);
+ ServerSession serverSession = EasyMock.createMock(ServerSession.class);
+
EasyMock.expect(channelSession.getServerSession()).andReturn(serverSession);
+
EasyMock.expect(serverSession.getAttribute(KarafJaasAuthenticator.SUBJECT_ATTRIBUTE_KEY)).andReturn(null);
+ EasyMock.expect(serverSession.close(false)).andReturn(null);
+
+ EasyMock.replay(session, sessionFactory, env, exitCallback,
channelSession, serverSession);
+
+ ShellCommand shellCommand = new ShellCommand(sessionFactory,
"log:tail");
+ shellCommand.setInputStream(new ByteArrayInputStream(new byte[0]));
+ shellCommand.setOutputStream(new ByteArrayOutputStream());
+ shellCommand.setErrorStream(new ByteArrayOutputStream());
+ shellCommand.setExitCallback(exitCallback);
+
+ // Start the command (runs in a separate thread)
+ shellCommand.start(channelSession, env);
+
+ // Wait for the blocking command to start
+ Assert.assertTrue("Command should have started",
commandStarted.await(5, TimeUnit.SECONDS));
+
+ // Simulate SSH disconnect by calling destroy
+ shellCommand.destroy(channelSession);
+
+ // The command thread should finish within a reasonable time
+ Assert.assertTrue("Command thread should have been interrupted and
finished",
+ commandFinished.await(5, TimeUnit.SECONDS));
+
+ EasyMock.verify(session);
+ }
+}
