1 | /** |
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2 | * Licensed to the Apache Software Foundation (ASF) under one |
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3 | * or more contributor license agreements. See the NOTICE file |
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4 | * distributed with this work for additional information |
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5 | * regarding copyright ownership. The ASF licenses this file |
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6 | * to you under the Apache License, Version 2.0 (the |
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7 | * "License"); you may not use this file except in compliance |
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8 | * with the License. You may obtain a copy of the License at |
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9 | * |
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10 | * http://www.apache.org/licenses/LICENSE-2.0 |
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11 | * |
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12 | * Unless required by applicable law or agreed to in writing, software |
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13 | * distributed under the License is distributed on an "AS IS" BASIS, |
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14 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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15 | * See the License for the specific language governing permissions and |
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16 | * limitations under the License. |
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17 | */ |
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18 | |
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19 | package org.apache.hadoop.util; |
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20 | |
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21 | import java.io.File; |
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22 | import java.io.IOException; |
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23 | |
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24 | /** |
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25 | * Class that provides utility functions for checking disk problem |
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26 | */ |
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27 | |
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28 | public class DiskChecker { |
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29 | |
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30 | public static class DiskErrorException extends IOException { |
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31 | public DiskErrorException(String msg) { |
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32 | super(msg); |
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33 | } |
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34 | } |
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35 | |
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36 | public static class DiskOutOfSpaceException extends IOException { |
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37 | public DiskOutOfSpaceException(String msg) { |
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38 | super(msg); |
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39 | } |
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40 | } |
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41 | |
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42 | /** |
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43 | * The semantics of mkdirsWithExistsCheck method is different from the mkdirs |
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44 | * method provided in the Sun's java.io.File class in the following way: |
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45 | * While creating the non-existent parent directories, this method checks for |
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46 | * the existence of those directories if the mkdir fails at any point (since |
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47 | * that directory might have just been created by some other process). |
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48 | * If both mkdir() and the exists() check fails for any seemingly |
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49 | * non-existent directory, then we signal an error; Sun's mkdir would signal |
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50 | * an error (return false) if a directory it is attempting to create already |
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51 | * exists or the mkdir fails. |
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52 | * @param dir |
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53 | * @return true on success, false on failure |
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54 | */ |
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55 | public static boolean mkdirsWithExistsCheck(File dir) { |
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56 | if (dir.mkdir() || dir.exists()) { |
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57 | return true; |
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58 | } |
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59 | File canonDir = null; |
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60 | try { |
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61 | canonDir = dir.getCanonicalFile(); |
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62 | } catch (IOException e) { |
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63 | return false; |
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64 | } |
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65 | String parent = canonDir.getParent(); |
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66 | return (parent != null) && |
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67 | (mkdirsWithExistsCheck(new File(parent)) && |
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68 | (canonDir.mkdir() || canonDir.exists())); |
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69 | } |
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70 | |
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71 | public static void checkDir(File dir) throws DiskErrorException { |
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72 | if (!mkdirsWithExistsCheck(dir)) |
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73 | throw new DiskErrorException("can not create directory: " |
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74 | + dir.toString()); |
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75 | |
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76 | if (!dir.isDirectory()) |
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77 | throw new DiskErrorException("not a directory: " |
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78 | + dir.toString()); |
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79 | |
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80 | if (!dir.canRead()) |
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81 | throw new DiskErrorException("directory is not readable: " |
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82 | + dir.toString()); |
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83 | |
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84 | if (!dir.canWrite()) |
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85 | throw new DiskErrorException("directory is not writable: " |
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86 | + dir.toString()); |
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87 | } |
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88 | |
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89 | } |
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