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.OutputStreamWriter;
021import java.io.PrintWriter;
022import java.security.PrivilegedExceptionAction;
023
024import javax.servlet.ServletContext;
025import javax.servlet.ServletException;
026import javax.servlet.http.HttpServletRequest;
027import javax.servlet.http.HttpServletResponse;
028
029import org.apache.commons.logging.Log;
030import org.apache.commons.logging.LogFactory;
031import org.apache.hadoop.conf.Configuration;
032import org.apache.hadoop.hdfs.security.token.delegation.DelegationTokenIdentifier;
033import org.apache.hadoop.hdfs.security.token.delegation.DelegationUtilsClient;
034import org.apache.hadoop.security.UserGroupInformation;
035import org.apache.hadoop.security.token.Token;
036
037import com.google.common.base.Charsets;
038
039/**
040 * Renew delegation tokens over http for use in hftp.
041 */
042@SuppressWarnings("serial")
043public class RenewDelegationTokenServlet extends DfsServlet {
044  private static final Log LOG = LogFactory.getLog(RenewDelegationTokenServlet.class);
045  
046  @Override
047  protected void doGet(final HttpServletRequest req, final HttpServletResponse resp)
048      throws ServletException, IOException {
049    final UserGroupInformation ugi;
050    final ServletContext context = getServletContext();
051    final Configuration conf = NameNodeHttpServer.getConfFromContext(context);
052    try {
053      ugi = getUGI(req, conf);
054    } catch(IOException ioe) {
055      LOG.info("Request for token received with no authentication from "
056          + req.getRemoteAddr(), ioe);
057      resp.sendError(HttpServletResponse.SC_FORBIDDEN, 
058          "Unable to identify or authenticate user");
059      return;
060    }
061    final NameNode nn = NameNodeHttpServer.getNameNodeFromContext(context);
062    String tokenString = req.getParameter(DelegationUtilsClient.TOKEN);
063    if (tokenString == null) {
064      resp.sendError(HttpServletResponse.SC_MULTIPLE_CHOICES,
065                     "Token to renew not specified");
066    }
067    final Token<DelegationTokenIdentifier> token = 
068      new Token<DelegationTokenIdentifier>();
069    token.decodeFromUrlString(tokenString);
070    
071    try {
072      long result = ugi.doAs(new PrivilegedExceptionAction<Long>() {
073        @Override
074        public Long run() throws Exception {
075          return nn.getRpcServer().renewDelegationToken(token);
076        }
077      });
078      final PrintWriter os = new PrintWriter(new OutputStreamWriter(
079          resp.getOutputStream(), Charsets.UTF_8));
080      os.println(result);
081      os.close();
082    } catch(Exception e) {
083      // transfer exception over the http
084      String exceptionClass = e.getClass().getName();
085      String exceptionMsg = e.getLocalizedMessage();
086      String strException = exceptionClass + ";" + exceptionMsg;
087      LOG.info("Exception while renewing token. Re-throwing. s=" + strException, e);
088      resp.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR, strException);
089    }
090  }
091}