com.cloudera.hadoop.hdfs.nfs.nfs4.handlers.ACCESSHandler.java Source code

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/**
 * Copyright 2011 The Apache Software Foundation
 *
 * 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 com.cloudera.hadoop.hdfs.nfs.nfs4.handlers;

import static com.cloudera.hadoop.hdfs.nfs.nfs4.Constants.*;

import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.fs.permission.FsPermission;
import com.cloudera.hadoop.hdfs.nfs.nfs4.NFS4Exception;
import com.cloudera.hadoop.hdfs.nfs.nfs4.NFS4Handler;
import com.cloudera.hadoop.hdfs.nfs.nfs4.Session;
import com.cloudera.hadoop.hdfs.nfs.nfs4.UserIDMapper;
import com.cloudera.hadoop.hdfs.nfs.nfs4.requests.ACCESSRequest;
import com.cloudera.hadoop.hdfs.nfs.nfs4.requests.CompoundRequest;
import com.cloudera.hadoop.hdfs.nfs.nfs4.responses.ACCESSResponse;
import com.cloudera.hadoop.hdfs.nfs.security.AuthenticatedCredentials;
import org.apache.log4j.Logger;

public class ACCESSHandler extends OperationRequestHandler<ACCESSRequest, ACCESSResponse> {

    protected static final Logger LOGGER = Logger.getLogger(ACCESSHandler.class);
    public static final int ACCESS_READ = 0x04;
    public static final int ACCESS_WRITE = 0x02;
    public static final int ACCESS_EXECUTE = 0x01;

    @Override
    protected ACCESSResponse doHandle(NFS4Handler server, Session session, ACCESSRequest request)
            throws NFS4Exception {
        if (session.getCurrentFileHandle() == null) {
            throw new NFS4Exception(NFS4ERR_NOFILEHANDLE);
        }
        CompoundRequest compoundRequest = session.getCompoundRequest();
        AuthenticatedCredentials creds = compoundRequest.getCredentials();
        Path path = server.getPath(session.getCurrentFileHandle());
        try {

            UserIDMapper mapper = UserIDMapper.get(session.getConfiguration());
            String user = mapper.getUserForUID(creds.getUID(), null);
            if (user == null) {
                throw new Exception("Could not map " + creds.getUID() + " to user");
            }
            String group = mapper.getGroupForGID(creds.getGID(), null);
            if (group == null) {
                throw new Exception("Could not map " + creds.getGID() + " to group");
            }

            FileSystem fs = session.getFileSystem();
            FileStatus fileStatus = fs.getFileStatus(path);
            FsPermission perms = fileStatus.getPermission();
            //FsAction action = perms.getUserAction(); // always comes back ALL??

            int permissions = perms.toShort();
            int saved = permissions;
            int rtn = setPerms(permissions, false);
            permissions = permissions >> 3;
            if (group.equals(fileStatus.getGroup())) {
                rtn = setPerms(permissions, true);
            }
            permissions = permissions >> 3;
            if (user.equals(fileStatus.getOwner())) {
                rtn = setPerms(permissions, true);
            }
            if (LOGGER.isDebugEnabled()) {
                LOGGER.debug("Checking access for '" + user + "' and path " + path + " owned by '"
                        + fileStatus.getOwner() + "' permissions " + Integer.toOctalString(saved) + ", Returning "
                        + Integer.toHexString(rtn));
            }
            int access = rtn & request.getAccess();

            ACCESSResponse response = createResponse();
            response.setStatus(NFS4_OK);
            response.setAccess(access);
            response.setSupported(access);
            return response;
        } catch (Exception e) {
            throw new NFS4Exception(NFS4ERR_SERVERFAULT, e);
        }
    }

    protected int setPerms(int permissions, boolean isOwner) {
        int rtn = 0;
        if (isSet(permissions, ACCESS_READ)) {
            rtn |= NFS_ACCESS_READ;
            rtn |= NFS_ACCESS_LOOKUP;
        }
        if (isSet(permissions, ACCESS_WRITE)) {
            rtn |= NFS_ACCESS_MODIFY;
            rtn |= NFS_ACCESS_EXTEND;
            if (isOwner) {
                rtn |= NFS_ACCESS_DELETE;
            }
        }
        if (isSet(permissions, ACCESS_EXECUTE)) {
            rtn |= NFS_ACCESS_EXECUTE;
        }
        return rtn;
    }

    protected boolean isSet(int access, int mode) {
        return (access & mode) == mode;
    }

    @Override
    protected ACCESSResponse createResponse() {
        return new ACCESSResponse();
    }
}