org.apache.hadoop.fs.viewfs.ChRootedFs Maven / Gradle / Ivy

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/**
 * 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.hadoop.fs.viewfs;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;
import java.util.EnumSet;
import java.util.List;

import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.fs.AbstractFileSystem;
import org.apache.hadoop.fs.BlockLocation;
import org.apache.hadoop.fs.CreateFlag;
import org.apache.hadoop.fs.FSDataInputStream;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.FileChecksum;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FsServerDefaults;
import org.apache.hadoop.fs.FsStatus;
import org.apache.hadoop.fs.Options.ChecksumOpt;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.fs.UnresolvedLinkException;
import org.apache.hadoop.fs.permission.FsPermission;
import org.apache.hadoop.security.token.Token;
import org.apache.hadoop.util.Progressable;

/**
 * ChrootedFs is a file system with its root some path
 * below the root of its base file system.
 * Example: For a base file system hdfs://nn1/ with chRoot at /usr/foo, the
 * members will be setup as shown below.
 * 
 * myFs is the base file system and points to hdfs at nn1
 * myURI is hdfs://nn1/user/foo
 * chRootPathPart is /user/foo
 * workingDir is a directory related to chRoot
 * 
 * 
 * The paths are resolved as follows by ChRootedFileSystem:
 * 
 *  Absolute path /a/b/c is resolved to /user/foo/a/b/c at myFs
 *  Relative path x/y is resolved to /user/foo//x/y
 * 

 * 
 */
@InterfaceAudience.Private
@InterfaceStability.Evolving /*Evolving for a release,to be changed to Stable */
class ChRootedFs extends AbstractFileSystem {
  private final AbstractFileSystem myFs;  // the base file system whose root is changed
  private final URI myUri; // the base URI + the chroot
  private final Path chRootPathPart; // the root below the root of the base
  private final String chRootPathPartString;
  
  protected AbstractFileSystem getMyFs() {
    return myFs;
  }
  
  /**
   * 
   * @param path
   * @return return full path including the chroot
   */
  protected Path fullPath(final Path path) {
    super.checkPath(path);
    return new Path((chRootPathPart.isRoot() ? "" : chRootPathPartString)
        + path.toUri().getPath());
  }
  
  public ChRootedFs(final AbstractFileSystem fs, final Path theRoot)
    throws URISyntaxException {
    super(fs.getUri(), fs.getUri().getScheme(),
        fs.getUri().getAuthority() != null, fs.getUriDefaultPort());
    myFs = fs;
    myFs.checkPath(theRoot);
    chRootPathPart = new Path(myFs.getUriPath(theRoot));
    chRootPathPartString = chRootPathPart.toUri().getPath();
    /*
     * We are making URI include the chrootedPath: e.g. file:///chrootedPath.
     * This is questionable since Path#makeQualified(uri, path) ignores
     * the pathPart of a uri. Since this class is internal we can ignore
     * this issue but if we were to make it external then this needs
     * to be resolved.
     */
    // Handle the two cases:
    //              scheme:/// and scheme://authority/
    myUri = new URI(myFs.getUri().toString() + 
        (myFs.getUri().getAuthority() == null ? "" :  Path.SEPARATOR) +
          chRootPathPart.toString().substring(1));
    super.checkPath(theRoot);
  }
  
  @Override
  public URI getUri() {
    return myUri;
  }

  
  /**
   *  
   * Strip out the root from the path.
   * 
   * @param p - fully qualified path p
   * @return -  the remaining path  without the begining /
   */
  public String stripOutRoot(final Path p) {
    try {
     checkPath(p);
    } catch (IllegalArgumentException e) {
      throw new RuntimeException("Internal Error - path " + p +
          " should have been with URI" + myUri);
    }
    String pathPart = p.toUri().getPath();
    return  (pathPart.length() == chRootPathPartString.length()) ?
        "" : pathPart.substring(chRootPathPartString.length() +
            (chRootPathPart.isRoot() ? 0 : 1));
  }
  

  @Override
  public Path getHomeDirectory() {
    return myFs.getHomeDirectory();
  }
  
  @Override
  public Path getInitialWorkingDirectory() {
    /*
     * 3 choices here: return null or / or strip out the root out of myFs's
     *  inital wd. 
     * Only reasonable choice for initialWd for chrooted fds is null 
     */
    return null;
  }
  
  
  public Path getResolvedQualifiedPath(final Path f)
      throws FileNotFoundException {
    return myFs.makeQualified(
        new Path(chRootPathPartString + f.toUri().toString()));
  }
  
  @Override
  public FSDataOutputStream createInternal(final Path f,
      final EnumSet flag, final FsPermission absolutePermission,
      final int bufferSize, final short replication, final long blockSize,
      final Progressable progress, final ChecksumOpt checksumOpt,
      final boolean createParent) throws IOException, UnresolvedLinkException {
    return myFs.createInternal(fullPath(f), flag,
        absolutePermission, bufferSize,
        replication, blockSize, progress, checksumOpt, createParent);
  }

  @Override
  public boolean delete(final Path f, final boolean recursive) 
      throws IOException, UnresolvedLinkException {
    return myFs.delete(fullPath(f), recursive);
  }

  @Override
  public BlockLocation[] getFileBlockLocations(final Path f, final long start,
      final long len) throws IOException, UnresolvedLinkException {
    return myFs.getFileBlockLocations(fullPath(f), start, len);
  }

  @Override
  public FileChecksum getFileChecksum(final Path f) 
      throws IOException, UnresolvedLinkException {
    return myFs.getFileChecksum(fullPath(f));
  }

  @Override
  public FileStatus getFileStatus(final Path f) 
      throws IOException, UnresolvedLinkException {
    return myFs.getFileStatus(fullPath(f));
  }

  @Override
  public FileStatus getFileLinkStatus(final Path f) 
    throws IOException, UnresolvedLinkException {
    return myFs.getFileLinkStatus(fullPath(f));
  }
  
  @Override
  public FsStatus getFsStatus() throws IOException {
    return myFs.getFsStatus();
  }

  @Override
  public FsServerDefaults getServerDefaults() throws IOException {
    return myFs.getServerDefaults();
  }

  @Override
  public int getUriDefaultPort() {
    return myFs.getUriDefaultPort();
  }

  @Override
  public FileStatus[] listStatus(final Path f) 
      throws IOException, UnresolvedLinkException {
    return myFs.listStatus(fullPath(f));
  }

  @Override
  public void mkdir(final Path dir, final FsPermission permission,
      final boolean createParent) throws IOException, UnresolvedLinkException {
    myFs.mkdir(fullPath(dir), permission, createParent);
    
  }

  @Override
  public FSDataInputStream open(final Path f, final int bufferSize) 
    throws IOException, UnresolvedLinkException {
    return myFs.open(fullPath(f), bufferSize);
  }

  @Override
  public void renameInternal(final Path src, final Path dst)
    throws IOException, UnresolvedLinkException {
    // note fullPath will check that paths are relative to this FileSystem.
    // Hence both are in same file system and a rename is valid
    myFs.renameInternal(fullPath(src), fullPath(dst));
  }
  
  @Override
  public void renameInternal(final Path src, final Path dst, 
      final boolean overwrite)
    throws IOException, UnresolvedLinkException {
    // note fullPath will check that paths are relative to this FileSystem.
    // Hence both are in same file system and a rename is valid
    myFs.renameInternal(fullPath(src), fullPath(dst), overwrite);
  }

  @Override
  public void setOwner(final Path f, final String username,
      final String groupname)
    throws IOException, UnresolvedLinkException {
    myFs.setOwner(fullPath(f), username, groupname);
    
  }

  @Override
  public void setPermission(final Path f, final FsPermission permission)
    throws IOException, UnresolvedLinkException {
    myFs.setPermission(fullPath(f), permission);
  }

  @Override
  public boolean setReplication(final Path f, final short replication)
    throws IOException, UnresolvedLinkException {
    return myFs.setReplication(fullPath(f), replication);
  }

  @Override
  public void setTimes(final Path f, final long mtime, final long atime) 
      throws IOException, UnresolvedLinkException {
    myFs.setTimes(fullPath(f), mtime, atime);
  }

  @Override
  public void setVerifyChecksum(final boolean verifyChecksum) 
      throws IOException, UnresolvedLinkException {
    myFs.setVerifyChecksum(verifyChecksum);
  }

  @Override
  public boolean supportsSymlinks() {
    return myFs.supportsSymlinks();
  }

  @Override
  public void createSymlink(final Path target, final Path link,
      final boolean createParent) throws IOException, UnresolvedLinkException {
    /*
     * We leave the link alone:
     * If qualified or link relative then of course it is okay.
     * If absolute (ie / relative) then the link has to be resolved
     * relative to the changed root.
     */
    myFs.createSymlink(fullPath(target), link, createParent);
  }

  @Override
  public Path getLinkTarget(final Path f) throws IOException {
    return myFs.getLinkTarget(fullPath(f));
  }
  
  
  @Override
  public List> getDelegationTokens(String renewer) throws IOException {
    return myFs.getDelegationTokens(renewer);
  }
}