001/**
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *     http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018package org.apache.hadoop.hbase.io.hfile.bucket;
019
020import java.io.File;
021import java.io.IOException;
022import java.security.MessageDigest;
023import java.security.NoSuchAlgorithmException;
024
025import org.apache.hadoop.hbase.util.Bytes;
026import org.apache.hadoop.util.Shell;
027import org.apache.yetus.audience.InterfaceAudience;
028import org.slf4j.Logger;
029import org.slf4j.LoggerFactory;
030
031/**
032 * A class implementing PersistentIOEngine interface supports file integrity verification
033 * for {@link BucketCache} which use persistent IOEngine
034 */
035@InterfaceAudience.Private
036public abstract class PersistentIOEngine implements IOEngine {
037  private static final Logger LOG = LoggerFactory.getLogger(PersistentIOEngine.class);
038  private static final DuFileCommand DU = new DuFileCommand(new String[] {"du", ""});
039  protected final String[] filePaths;
040
041  public PersistentIOEngine(String... filePaths) {
042    this.filePaths = filePaths;
043  }
044
045  /**
046   * Verify cache files's integrity
047   * @param algorithm the backingMap persistence path
048   */
049  protected void verifyFileIntegrity(byte[] persistentChecksum, String algorithm)
050    throws IOException {
051    byte[] calculateChecksum = calculateChecksum(algorithm);
052    if (!Bytes.equals(persistentChecksum, calculateChecksum)) {
053      throw new IOException("Mismatch of checksum! The persistent checksum is " +
054      Bytes.toString(persistentChecksum) + ", but the calculate checksum is " +
055        Bytes.toString(calculateChecksum));
056    }
057  }
058
059  /**
060   * Using an encryption algorithm to calculate a checksum, the default encryption algorithm is MD5
061   * @return the checksum which is convert to HexString
062   * @throws IOException something happened like file not exists
063   * @throws NoSuchAlgorithmException no such algorithm
064   */
065  protected byte[] calculateChecksum(String algorithm) {
066    try {
067      StringBuilder sb = new StringBuilder();
068      for (String filePath : filePaths){
069        File file = new File(filePath);
070        sb.append(filePath);
071        sb.append(getFileSize(filePath));
072        sb.append(file.lastModified());
073      }
074      MessageDigest messageDigest = MessageDigest.getInstance(algorithm);
075      messageDigest.update(Bytes.toBytes(sb.toString()));
076      return messageDigest.digest();
077    } catch (IOException ioex) {
078      LOG.error("Calculating checksum failed, because of ", ioex);
079      return new byte[0];
080    } catch (NoSuchAlgorithmException e) {
081      LOG.error("No such algorithm : " + algorithm + "!");
082      return new byte[0];
083    }
084  }
085
086  /**
087   * Using Linux command du to get file's real size
088   * @param filePath the file
089   * @return file's real size
090   * @throws IOException something happened like file not exists
091   */
092  private static long getFileSize(String filePath) throws IOException {
093    DU.setExecCommand(filePath);
094    DU.execute();
095    return Long.parseLong(DU.getOutput().split("\t")[0]);
096  }
097
098  private static class DuFileCommand extends Shell.ShellCommandExecutor {
099    private String[] execCommand;
100
101    DuFileCommand(String[] execString) {
102      super(execString);
103      execCommand = execString;
104    }
105
106    void setExecCommand(String filePath) {
107      this.execCommand[1] = filePath;
108    }
109
110    @Override
111    public String[] getExecString() {
112      return this.execCommand;
113    }
114  }
115}
116