/**
* 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.util;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.LocalFileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.fs.permission.FsAction;
import org.apache.hadoop.fs.permission.FsPermission;
/**
* Class that provides utility functions for checking disk problem
*/
public class DiskChecker {
public static class DiskErrorException extends IOException {
public DiskErrorException(String msg) {
super(msg);
}
}
public static class DiskOutOfSpaceException extends IOException {
public DiskOutOfSpaceException(String msg) {
super(msg);
}
}
/**
* The semantics of mkdirsWithExistsCheck method is different from the mkdirs
* method provided in the Sun's java.io.File class in the following way:
* While creating the non-existent parent directories, this method checks for
* the existence of those directories if the mkdir fails at any point (since
* that directory might have just been created by some other process).
* If both mkdir() and the exists() check fails for any seemingly
* non-existent directory, then we signal an error; Sun's mkdir would signal
* an error (return false) if a directory it is attempting to create already
* exists or the mkdir fails.
* @param dir
* @return true on success, false on failure
*/
public static boolean mkdirsWithExistsCheck(File dir) {
if (dir.mkdir() || dir.exists()) {
return true;
}
File canonDir = null;
try {
canonDir = dir.getCanonicalFile();
} catch (IOException e) {
return false;
}
String parent = canonDir.getParent();
return (parent != null) &&
(mkdirsWithExistsCheck(new File(parent)) &&
(canonDir.mkdir() || canonDir.exists()));
}
/**
* Create the directory if it doesn't exist and
* @param dir
* @throws DiskErrorException
*/
public static void checkDir(File dir) throws DiskErrorException {
if (!mkdirsWithExistsCheck(dir))
throw new DiskErrorException("can not create directory: "
+ dir.toString());
if (!dir.isDirectory())
throw new DiskErrorException("not a directory: "
+ dir.toString());
if (!dir.canRead())
throw new DiskErrorException("directory is not readable: "
+ dir.toString());
if (!dir.canWrite())
throw new DiskErrorException("directory is not writable: "
+ dir.toString());
}
private static void checkPermission(Path dir,
FsPermission expected, FsPermission actual)
throws IOException {
// Check for permissions
if (!actual.equals(expected)) {
throw new IOException("Incorrect permission for " + dir +
", expected: " + expected + ", while actual: " +
actual);
}
}
/**
* Create the directory or check permissions if it already exists.
*
* The semantics of mkdirsWithExistsAndPermissionCheck method is different
* from the mkdirs method provided in the Sun's java.io.File class in the
* following way:
* While creating the non-existent parent directories, this method checks for
* the existence of those directories if the mkdir fails at any point (since
* that directory might have just been created by some other process).
* If both mkdir() and the exists() check fails for any seemingly
* non-existent directory, then we signal an error; Sun's mkdir would signal
* an error (return false) if a directory it is attempting to create already
* exists or the mkdir fails.
* @param localFS local filesystem
* @param dir directory to be created or checked
* @param expected expected permission
* @return true on success, false on failure
*/
public static boolean mkdirsWithExistsAndPermissionCheck(
LocalFileSystem localFS, Path dir, FsPermission expected)
throws IOException {
File directory = new File(dir.makeQualified(localFS).toUri().getPath());
if (!directory.exists()) {
boolean created = mkdirsWithExistsCheck(directory);
if (created) {
localFS.setPermission(dir, expected);
return true;
}
}
checkPermission(dir, expected, localFS.getFileStatus(dir).getPermission());
return true;
}
/**
* Create the local directory if necessary, check permissions and also ensure
* it can be read from and written into.
* @param localFS local filesystem
* @param dir directory
* @param expected permission
* @throws DiskErrorException
* @throws IOException
*/
public static void checkDir(LocalFileSystem localFS, Path dir,
FsPermission expected)
throws DiskErrorException, IOException {
if (!mkdirsWithExistsAndPermissionCheck(localFS, dir, expected))
throw new DiskErrorException("can not create directory: "
+ dir.toString());
FileStatus stat = localFS.getFileStatus(dir);
FsPermission actual = stat.getPermission();
if (!stat.isDir())
throw new DiskErrorException("not a directory: "
+ dir.toString());
FsAction user = actual.getUserAction();
if (!user.implies(FsAction.READ))
throw new DiskErrorException("directory is not readable: "
+ dir.toString());
if (!user.implies(FsAction.WRITE))
throw new DiskErrorException("directory is not writable: "
+ dir.toString());
}
}