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, 013 * software distributed under the License is distributed on an 014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 015 * KIND, either express or implied. See the License for the 016 * specific language governing permissions and limitations 017 * under the License. 018 */ 019 package org.apache.commons.compress.archivers.zip; 020 021 import java.util.zip.CRC32; 022 import java.util.zip.ZipException; 023 024 /** 025 * Adds Unix file permission and UID/GID fields as well as symbolic 026 * link handling. 027 * 028 * <p>This class uses the ASi extra field in the format: 029 * <pre> 030 * Value Size Description 031 * ----- ---- ----------- 032 * (Unix3) 0x756e Short tag for this extra block type 033 * TSize Short total data size for this block 034 * CRC Long CRC-32 of the remaining data 035 * Mode Short file permissions 036 * SizDev Long symlink'd size OR major/minor dev num 037 * UID Short user ID 038 * GID Short group ID 039 * (var.) variable symbolic link filename 040 * </pre> 041 * taken from appnote.iz (Info-ZIP note, 981119) found at <a 042 * href="ftp://ftp.uu.net/pub/archiving/zip/doc/">ftp://ftp.uu.net/pub/archiving/zip/doc/</a></p> 043 044 * 045 * <p>Short is two bytes and Long is four bytes in big endian byte and 046 * word order, device numbers are currently not supported.</p> 047 * @NotThreadSafe 048 * 049 * <p>Since the documentation this class is based upon doesn't mention 050 * the character encoding of the file name at all, it is assumed that 051 * it uses the current platform's default encoding.</p> 052 */ 053 public class AsiExtraField implements ZipExtraField, UnixStat, Cloneable { 054 055 private static final ZipShort HEADER_ID = new ZipShort(0x756E); 056 private static final int WORD = 4; 057 /** 058 * Standard Unix stat(2) file mode. 059 */ 060 private int mode = 0; 061 /** 062 * User ID. 063 */ 064 private int uid = 0; 065 /** 066 * Group ID. 067 */ 068 private int gid = 0; 069 /** 070 * File this entry points to, if it is a symbolic link. 071 * 072 * <p>empty string - if entry is not a symbolic link.</p> 073 */ 074 private String link = ""; 075 /** 076 * Is this an entry for a directory? 077 */ 078 private boolean dirFlag = false; 079 080 /** 081 * Instance used to calculate checksums. 082 */ 083 private CRC32 crc = new CRC32(); 084 085 /** Constructor for AsiExtraField. */ 086 public AsiExtraField() { 087 } 088 089 /** 090 * The Header-ID. 091 * @return the value for the header id for this extrafield 092 */ 093 public ZipShort getHeaderId() { 094 return HEADER_ID; 095 } 096 097 /** 098 * Length of the extra field in the local file data - without 099 * Header-ID or length specifier. 100 * @return a <code>ZipShort</code> for the length of the data of this extra field 101 */ 102 public ZipShort getLocalFileDataLength() { 103 return new ZipShort(WORD // CRC 104 + 2 // Mode 105 + WORD // SizDev 106 + 2 // UID 107 + 2 // GID 108 + getLinkedFile().getBytes().length); 109 // Uses default charset - see class Javadoc 110 } 111 112 /** 113 * Delegate to local file data. 114 * @return the centralDirectory length 115 */ 116 public ZipShort getCentralDirectoryLength() { 117 return getLocalFileDataLength(); 118 } 119 120 /** 121 * The actual data to put into local file data - without Header-ID 122 * or length specifier. 123 * @return get the data 124 */ 125 public byte[] getLocalFileDataData() { 126 // CRC will be added later 127 byte[] data = new byte[getLocalFileDataLength().getValue() - WORD]; 128 System.arraycopy(ZipShort.getBytes(getMode()), 0, data, 0, 2); 129 130 byte[] linkArray = getLinkedFile().getBytes(); // Uses default charset - see class Javadoc 131 // CheckStyle:MagicNumber OFF 132 System.arraycopy(ZipLong.getBytes(linkArray.length), 133 0, data, 2, WORD); 134 135 System.arraycopy(ZipShort.getBytes(getUserId()), 136 0, data, 6, 2); 137 System.arraycopy(ZipShort.getBytes(getGroupId()), 138 0, data, 8, 2); 139 140 System.arraycopy(linkArray, 0, data, 10, linkArray.length); 141 // CheckStyle:MagicNumber ON 142 143 crc.reset(); 144 crc.update(data); 145 long checksum = crc.getValue(); 146 147 byte[] result = new byte[data.length + WORD]; 148 System.arraycopy(ZipLong.getBytes(checksum), 0, result, 0, WORD); 149 System.arraycopy(data, 0, result, WORD, data.length); 150 return result; 151 } 152 153 /** 154 * Delegate to local file data. 155 * @return the local file data 156 */ 157 public byte[] getCentralDirectoryData() { 158 return getLocalFileDataData(); 159 } 160 161 /** 162 * Set the user id. 163 * @param uid the user id 164 */ 165 public void setUserId(int uid) { 166 this.uid = uid; 167 } 168 169 /** 170 * Get the user id. 171 * @return the user id 172 */ 173 public int getUserId() { 174 return uid; 175 } 176 177 /** 178 * Set the group id. 179 * @param gid the group id 180 */ 181 public void setGroupId(int gid) { 182 this.gid = gid; 183 } 184 185 /** 186 * Get the group id. 187 * @return the group id 188 */ 189 public int getGroupId() { 190 return gid; 191 } 192 193 /** 194 * Indicate that this entry is a symbolic link to the given filename. 195 * 196 * @param name Name of the file this entry links to, empty String 197 * if it is not a symbolic link. 198 */ 199 public void setLinkedFile(String name) { 200 link = name; 201 mode = getMode(mode); 202 } 203 204 /** 205 * Name of linked file 206 * 207 * @return name of the file this entry links to if it is a 208 * symbolic link, the empty string otherwise. 209 */ 210 public String getLinkedFile() { 211 return link; 212 } 213 214 /** 215 * Is this entry a symbolic link? 216 * @return true if this is a symbolic link 217 */ 218 public boolean isLink() { 219 return getLinkedFile().length() != 0; 220 } 221 222 /** 223 * File mode of this file. 224 * @param mode the file mode 225 */ 226 public void setMode(int mode) { 227 this.mode = getMode(mode); 228 } 229 230 /** 231 * File mode of this file. 232 * @return the file mode 233 */ 234 public int getMode() { 235 return mode; 236 } 237 238 /** 239 * Indicate whether this entry is a directory. 240 * @param dirFlag if true, this entry is a directory 241 */ 242 public void setDirectory(boolean dirFlag) { 243 this.dirFlag = dirFlag; 244 mode = getMode(mode); 245 } 246 247 /** 248 * Is this entry a directory? 249 * @return true if this entry is a directory 250 */ 251 public boolean isDirectory() { 252 return dirFlag && !isLink(); 253 } 254 255 /** 256 * Populate data from this array as if it was in local file data. 257 * @param data an array of bytes 258 * @param offset the start offset 259 * @param length the number of bytes in the array from offset 260 * @throws ZipException on error 261 */ 262 public void parseFromLocalFileData(byte[] data, int offset, int length) 263 throws ZipException { 264 265 long givenChecksum = ZipLong.getValue(data, offset); 266 byte[] tmp = new byte[length - WORD]; 267 System.arraycopy(data, offset + WORD, tmp, 0, length - WORD); 268 crc.reset(); 269 crc.update(tmp); 270 long realChecksum = crc.getValue(); 271 if (givenChecksum != realChecksum) { 272 throw new ZipException("bad CRC checksum " 273 + Long.toHexString(givenChecksum) 274 + " instead of " 275 + Long.toHexString(realChecksum)); 276 } 277 278 int newMode = ZipShort.getValue(tmp, 0); 279 // CheckStyle:MagicNumber OFF 280 byte[] linkArray = new byte[(int) ZipLong.getValue(tmp, 2)]; 281 uid = ZipShort.getValue(tmp, 6); 282 gid = ZipShort.getValue(tmp, 8); 283 284 if (linkArray.length == 0) { 285 link = ""; 286 } else { 287 System.arraycopy(tmp, 10, linkArray, 0, linkArray.length); 288 link = new String(linkArray); // Uses default charset - see class Javadoc 289 } 290 // CheckStyle:MagicNumber ON 291 setDirectory((newMode & DIR_FLAG) != 0); 292 setMode(newMode); 293 } 294 295 /** 296 * Doesn't do anything special since this class always uses the 297 * same data in central directory and local file data. 298 */ 299 public void parseFromCentralDirectoryData(byte[] buffer, int offset, 300 int length) 301 throws ZipException { 302 parseFromLocalFileData(buffer, offset, length); 303 } 304 305 /** 306 * Get the file mode for given permissions with the correct file type. 307 * @param mode the mode 308 * @return the type with the mode 309 */ 310 protected int getMode(int mode) { 311 int type = FILE_FLAG; 312 if (isLink()) { 313 type = LINK_FLAG; 314 } else if (isDirectory()) { 315 type = DIR_FLAG; 316 } 317 return type | (mode & PERM_MASK); 318 } 319 320 @Override 321 public Object clone() { 322 try { 323 AsiExtraField cloned = (AsiExtraField) super.clone(); 324 cloned.crc = new CRC32(); 325 return cloned; 326 } catch (CloneNotSupportedException cnfe) { 327 // impossible 328 throw new RuntimeException(cnfe); 329 } 330 } 331 }