1 files changed, 147 insertions, 0 deletions
diff --git a/src/main/java/com/google/gerrit/server/ssh/SshServlet.java b/src/main/java/com/google/gerrit/server/ssh/SshServlet.java
new file mode 100644
index 0000000000..9e93d6a338
--- /dev/null
+++ b/src/main/java/com/google/gerrit/server/ssh/SshServlet.java
@@ -0,0 +1,147 @@
+// Copyright 2008 Google Inc.
+//
+// Licensed 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 com.google.gerrit.server.ssh;
+
+import com.google.gerrit.client.rpc.Common;
+import com.google.gerrit.server.GerritServer;
+import com.google.gwtjsonrpc.server.XsrfException;
+import com.google.gwtorm.client.OrmException;
+
+import org.apache.sshd.SshServer;
+import org.apache.sshd.common.NamedFactory;
+import org.apache.sshd.common.keyprovider.FileKeyPairProvider;
+import org.apache.sshd.server.UserAuth;
+import org.apache.sshd.server.auth.UserAuthPublicKey;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.File;
+import java.io.IOException;
+import java.io.PrintWriter;
+import java.util.Arrays;
+
+import javax.servlet.ServletConfig;
+import javax.servlet.ServletException;
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+/**
+ * Servlet hosting an SSH daemon on another port. During a standard HTTP GET
+ * request the servlet returns the hostname and port number back to the client
+ * in the form <code>${host} ${port}</code>.
+ * <p>
+ * Use a Git URL such as <code>ssh://${email}@${host}:${port}/${path}</code>,
+ * e.g. <code>ssh://sop@google.com@gerrit.com:8010/tools/gerrit.git</code> to
+ * access the SSH daemon itself.
+ * <p>
+ * Versions of Git before 1.5.3 may require setting the username and port
+ * properties in the user's <code>~/.ssh/config</code> file, and using a host
+ * alias through a URL such as <code>gerrit-alias:/tools/gerrit.git:
+ * <pre>
+ * Host gerrit-alias
+ *  User sop@google.com
+ *  Hostname gerrit.com
+ *  Port 8010
+ * </pre>
+ */
+public class SshServlet extends HttpServlet {
+  private static SshServer sshd;
+  private static final Logger log = LoggerFactory.getLogger(SshServlet.class);
+
+  public static synchronized void startSshd() throws ServletException {
+    final GerritServer srv;
+    try {
+      srv = GerritServer.getInstance();
+    } catch (OrmException e) {
+      throw new ServletException("Cannot load GerritServer", e);
+    } catch (XsrfException e) {
+      throw new ServletException("Cannot load GerritServer", e);
+    }
+
+    final int myPort = Common.getGerritConfig().getSshdPort();
+    sshd = SshServer.setUpDefaultServer();
+    sshd.setPort(myPort);
+    sshd.setKeyPairProvider(new FileKeyPairProvider(new String[] {
+        new File(srv.getSitePath(), "ssh_host_rsa_key").getAbsolutePath(),
+        new File(srv.getSitePath(), "ssh_host_dsa_key").getAbsolutePath()}));
+    sshd.setUserAuthFactories(Arrays
+        .<NamedFactory<UserAuth>> asList(new UserAuthPublicKey.Factory()));
+    sshd.setPublickeyAuthenticator(new DatabasePubKeyAuth());
+    sshd.setCommandFactory(new GerritCommandFactory());
+    sshd.setShellFactory(new NoShell());
+
+    try {
+      sshd.start();
+      log.info("Started Gerrit SSHD on 0.0.0.0:" + myPort);
+    } catch (IOException e) {
+      log.error("Cannot start Gerrit SSHD on 0.0.0.0:" + myPort, e);
+      sshd = null;
+      throw new ServletException("Cannot start sshd on " + myPort, e);
+    }
+  }
+
+  public static synchronized void stopSshd() {
+    if (sshd != null) {
+      try {
+        sshd.stop();
+        log.info("Stopped Gerrit SSHD on 0.0.0.0:" + sshd.getPort());
+      } finally {
+        sshd = null;
+      }
+    }
+  }
+
+  public static synchronized int getSshdPort() {
+    return sshd != null ? sshd.getPort() : 0;
+  }
+
+  @Override
+  public void init(final ServletConfig config) throws ServletException {
+    super.init(config);
+    startSshd();
+  }
+
+  @Override
+  public void destroy() {
+    stopSshd();
+    super.destroy();
+  }
+
+  @Override
+  protected void doGet(final HttpServletRequest req,
+      final HttpServletResponse rsp) throws IOException {
+    rsp.setHeader("Expires", "Fri, 01 Jan 1980 00:00:00 GMT");
+    rsp.setHeader("Pragma", "no-cache");
+    rsp.setHeader("Cache-Control", "no-cache, must-revalidate");
+
+    final int port = getSshdPort();
+    final String out;
+    if (0 < port) {
+      out = req.getServerName() + " " + port;
+    } else {
+      out = "NOT_AVAILABLE";
+    }
+
+    rsp.setCharacterEncoding("UTF-8");
+    rsp.setContentType("text/plain");
+    final PrintWriter w = rsp.getWriter();
+    try {
+      w.write(out);
+    } finally {
+      w.close();
+    }
+  }
+}