001/**
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with this
004 * work for additional information regarding copyright ownership. The ASF
005 * licenses this file to you under the Apache License, Version 2.0 (the
006 * "License"); you may not use this file except in compliance with the License.
007 * You may obtain a copy of the License at
008 * 
009 * http://www.apache.org/licenses/LICENSE-2.0
010 * 
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
013 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
014 * License for the specific language governing permissions and limitations under
015 * the License.
016 */
017package org.apache.hadoop.hdfs.server.namenode;
018
019import java.io.IOException;
020import java.io.PrintStream;
021import java.security.PrivilegedExceptionAction;
022
023import javax.servlet.ServletContext;
024import javax.servlet.ServletException;
025import javax.servlet.http.HttpServletRequest;
026import javax.servlet.http.HttpServletResponse;
027
028import org.apache.commons.logging.Log;
029import org.apache.commons.logging.LogFactory;
030import org.apache.hadoop.conf.Configuration;
031import org.apache.hadoop.hdfs.security.token.delegation.DelegationTokenIdentifier;
032import org.apache.hadoop.security.UserGroupInformation;
033import org.apache.hadoop.security.token.Token;
034
035/**
036 * Renew delegation tokens over http for use in hftp.
037 */
038@SuppressWarnings("serial")
039public class RenewDelegationTokenServlet extends DfsServlet {
040  private static final Log LOG = LogFactory.getLog(RenewDelegationTokenServlet.class);
041  public static final String PATH_SPEC = "/renewDelegationToken";
042  public static final String TOKEN = "token";
043  
044  @Override
045  protected void doGet(final HttpServletRequest req, final HttpServletResponse resp)
046      throws ServletException, IOException {
047    final UserGroupInformation ugi;
048    final ServletContext context = getServletContext();
049    final Configuration conf = NameNodeHttpServer.getConfFromContext(context);
050    try {
051      ugi = getUGI(req, conf);
052    } catch(IOException ioe) {
053      LOG.info("Request for token received with no authentication from "
054          + req.getRemoteAddr(), ioe);
055      resp.sendError(HttpServletResponse.SC_FORBIDDEN, 
056          "Unable to identify or authenticate user");
057      return;
058    }
059    final NameNode nn = NameNodeHttpServer.getNameNodeFromContext(context);
060    String tokenString = req.getParameter(TOKEN);
061    if (tokenString == null) {
062      resp.sendError(HttpServletResponse.SC_MULTIPLE_CHOICES,
063                     "Token to renew not specified");
064    }
065    final Token<DelegationTokenIdentifier> token = 
066      new Token<DelegationTokenIdentifier>();
067    token.decodeFromUrlString(tokenString);
068    
069    try {
070      long result = ugi.doAs(new PrivilegedExceptionAction<Long>() {
071        public Long run() throws Exception {
072          return nn.getRpcServer().renewDelegationToken(token);
073        }
074      });
075      PrintStream os = new PrintStream(resp.getOutputStream());
076      os.println(result);
077      os.close();
078    } catch(Exception e) {
079      // transfer exception over the http
080      String exceptionClass = e.getClass().getName();
081      String exceptionMsg = e.getLocalizedMessage();
082      String strException = exceptionClass + ";" + exceptionMsg;
083      LOG.info("Exception while renewing token. Re-throwing. s=" + strException, e);
084      resp.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR, strException);
085    }
086  }
087}