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 */ 019package org.apache.commons.compress.archivers.ar; 020 021import java.io.EOFException; 022import java.io.IOException; 023import java.io.InputStream; 024import java.nio.charset.StandardCharsets; 025import java.util.Arrays; 026import java.util.regex.Pattern; 027 028import org.apache.commons.compress.archivers.ArchiveInputStream; 029import org.apache.commons.compress.utils.ArchiveUtils; 030import org.apache.commons.compress.utils.IOUtils; 031import org.apache.commons.compress.utils.ParsingUtils; 032 033/** 034 * Implements the "ar" archive format as an input stream. 035 * 036 * @NotThreadSafe 037 */ 038public class ArArchiveInputStream extends ArchiveInputStream<ArArchiveEntry> { 039 040 // offsets and length of meta data parts 041 private static final int NAME_OFFSET = 0; 042 private static final int NAME_LEN = 16; 043 private static final int LAST_MODIFIED_OFFSET = NAME_LEN; 044 045 private static final int LAST_MODIFIED_LEN = 12; 046 047 private static final int USER_ID_OFFSET = LAST_MODIFIED_OFFSET + LAST_MODIFIED_LEN; 048 049 private static final int USER_ID_LEN = 6; 050 051 private static final int GROUP_ID_OFFSET = USER_ID_OFFSET + USER_ID_LEN; 052 private static final int GROUP_ID_LEN = 6; 053 private static final int FILE_MODE_OFFSET = GROUP_ID_OFFSET + GROUP_ID_LEN; 054 private static final int FILE_MODE_LEN = 8; 055 private static final int LENGTH_OFFSET = FILE_MODE_OFFSET + FILE_MODE_LEN; 056 private static final int LENGTH_LEN = 10; 057 static final String BSD_LONGNAME_PREFIX = "#1/"; 058 private static final int BSD_LONGNAME_PREFIX_LEN = BSD_LONGNAME_PREFIX.length(); 059 private static final Pattern BSD_LONGNAME_PATTERN = Pattern.compile("^" + BSD_LONGNAME_PREFIX + "\\d+"); 060 private static final String GNU_STRING_TABLE_NAME = "//"; 061 private static final Pattern GNU_LONGNAME_PATTERN = Pattern.compile("^/\\d+"); 062 063 /** 064 * Does the name look like it is a long name (or a name containing spaces) as encoded by BSD ar? 065 * <p> 066 * From the FreeBSD ar(5) man page: 067 * </p> 068 * <pre> 069 * BSD In the BSD variant, names that are shorter than 16 070 * characters and without embedded spaces are stored 071 * directly in this field. If a name has an embedded 072 * space, or if it is longer than 16 characters, then 073 * the string "#1/" followed by the decimal represen- 074 * tation of the length of the file name is placed in 075 * this field. The actual file name is stored immedi- 076 * ately after the archive header. The content of the 077 * archive member follows the file name. The ar_size 078 * field of the header (see below) will then hold the 079 * sum of the size of the file name and the size of 080 * the member. 081 * </pre> 082 * 083 * @since 1.3 084 */ 085 private static boolean isBSDLongName(final String name) { 086 return name != null && BSD_LONGNAME_PATTERN.matcher(name).matches(); 087 } 088 089 /** 090 * Is this the name of the "Archive String Table" as used by SVR4/GNU to store long file names? 091 * <p> 092 * GNU ar stores multiple extended file names in the data section of a file with the name "//", this record is referred to by future headers. 093 * </p> 094 * <p> 095 * A header references an extended file name by storing a "/" followed by a decimal offset to the start of the file name in the extended file name data 096 * section. 097 * </p> 098 * <p> 099 * The format of the "//" file itself is simply a list of the long file names, each separated by one or more LF characters. Note that the decimal offsets 100 * are number of characters, not line or string number within the "//" file. 101 * </p> 102 */ 103 private static boolean isGNUStringTable(final String name) { 104 return GNU_STRING_TABLE_NAME.equals(name); 105 } 106 107 /** 108 * Checks if the signature matches ASCII "!<arch>" followed by a single LF control character 109 * 110 * @param signature the bytes to check 111 * @param length the number of bytes to check 112 * @return true, if this stream is an Ar archive stream, false otherwise 113 */ 114 public static boolean matches(final byte[] signature, final int length) { 115 // 3c21 7261 6863 0a3e 116 117 return length >= 8 && signature[0] == 0x21 && signature[1] == 0x3c && signature[2] == 0x61 && signature[3] == 0x72 && signature[4] == 0x63 118 && signature[5] == 0x68 && signature[6] == 0x3e && signature[7] == 0x0a; 119 } 120 121 private long offset; 122 123 private boolean closed; 124 125 /* 126 * If getNextEntry has been called, the entry metadata is stored in currentEntry. 127 */ 128 private ArArchiveEntry currentEntry; 129 130 /** Storage area for extra long names (GNU ar). */ 131 private byte[] namebuffer; 132 133 /** 134 * The offset where the current entry started. -1 if no entry has been called 135 */ 136 private long entryOffset = -1; 137 138 /** Cached buffer for meta data - must only be used locally in the class (COMPRESS-172 - reduce garbage collection). */ 139 private final byte[] metaData = new byte[NAME_LEN + LAST_MODIFIED_LEN + USER_ID_LEN + GROUP_ID_LEN + FILE_MODE_LEN + LENGTH_LEN]; 140 141 /** 142 * Constructs an Ar input stream with the referenced stream 143 * 144 * @param inputStream the ar input stream 145 */ 146 public ArArchiveInputStream(final InputStream inputStream) { 147 super(inputStream, StandardCharsets.US_ASCII.name()); 148 } 149 150 private int asInt(final byte[] byteArray, final int offset, final int len) throws IOException { 151 return asInt(byteArray, offset, len, 10, false); 152 } 153 154 private int asInt(final byte[] byteArray, final int offset, final int len, final boolean treatBlankAsZero) throws IOException { 155 return asInt(byteArray, offset, len, 10, treatBlankAsZero); 156 } 157 158 private int asInt(final byte[] byteArray, final int offset, final int len, final int base) throws IOException { 159 return asInt(byteArray, offset, len, base, false); 160 } 161 162 private int asInt(final byte[] byteArray, final int offset, final int len, final int base, final boolean treatBlankAsZero) throws IOException { 163 final String string = ArchiveUtils.toAsciiString(byteArray, offset, len).trim(); 164 if (string.isEmpty() && treatBlankAsZero) { 165 return 0; 166 } 167 return ParsingUtils.parseIntValue(string, base); 168 } 169 170 private long asLong(final byte[] byteArray, final int offset, final int len) throws IOException { 171 return ParsingUtils.parseLongValue(ArchiveUtils.toAsciiString(byteArray, offset, len).trim()); 172 } 173 174 /* 175 * (non-Javadoc) 176 * 177 * @see java.io.InputStream#close() 178 */ 179 @Override 180 public void close() throws IOException { 181 if (!closed) { 182 closed = true; 183 in.close(); 184 } 185 currentEntry = null; 186 } 187 188 /** 189 * Reads the real name from the current stream assuming the very first bytes to be read are the real file name. 190 * 191 * @see #isBSDLongName 192 * 193 * @since 1.3 194 */ 195 private String getBSDLongName(final String bsdLongName) throws IOException { 196 final int nameLen = ParsingUtils.parseIntValue(bsdLongName.substring(BSD_LONGNAME_PREFIX_LEN)); 197 final byte[] name = IOUtils.readRange(in, nameLen); 198 final int read = name.length; 199 trackReadBytes(read); 200 if (read != nameLen) { 201 throw new EOFException(); 202 } 203 return ArchiveUtils.toAsciiString(name); 204 } 205 206 /** 207 * Gets an extended name from the GNU extended name buffer. 208 * 209 * @param offset pointer to entry within the buffer 210 * @return the extended file name; without trailing "/" if present. 211 * @throws IOException if name not found or buffer not set up 212 */ 213 private String getExtendedName(final int offset) throws IOException { 214 if (namebuffer == null) { 215 throw new IOException("Cannot process GNU long file name as no // record was found"); 216 } 217 for (int i = offset; i < namebuffer.length; i++) { 218 if (namebuffer[i] == '\012' || namebuffer[i] == 0) { 219 // Avoid array errors 220 if (i == 0) { 221 break; 222 } 223 if (namebuffer[i - 1] == '/') { 224 i--; // drop trailing / 225 } 226 227 // Check there is a something to return, otherwise break out of the loop 228 if (i - offset > 0) { 229 return ArchiveUtils.toAsciiString(namebuffer, offset, i - offset); 230 } 231 break; 232 } 233 } 234 throw new IOException("Failed to read entry: " + offset); 235 } 236 237 /** 238 * Returns the next AR entry in this stream. 239 * 240 * @return the next AR entry. 241 * @throws IOException if the entry could not be read 242 * @deprecated Use {@link #getNextEntry()}. 243 */ 244 @Deprecated 245 public ArArchiveEntry getNextArEntry() throws IOException { 246 if (currentEntry != null) { 247 final long entryEnd = entryOffset + currentEntry.getLength(); 248 final long skipped = org.apache.commons.io.IOUtils.skip(in, entryEnd - offset); 249 trackReadBytes(skipped); 250 currentEntry = null; 251 } 252 253 if (offset == 0) { 254 final byte[] expected = ArchiveUtils.toAsciiBytes(ArArchiveEntry.HEADER); 255 final byte[] realized = IOUtils.readRange(in, expected.length); 256 final int read = realized.length; 257 trackReadBytes(read); 258 if (read != expected.length) { 259 throw new IOException("Failed to read header. Occurred at byte: " + getBytesRead()); 260 } 261 if (!Arrays.equals(expected, realized)) { 262 throw new IOException("Invalid header " + ArchiveUtils.toAsciiString(realized)); 263 } 264 } 265 266 if (offset % 2 != 0) { 267 if (in.read() < 0) { 268 // hit eof 269 return null; 270 } 271 trackReadBytes(1); 272 } 273 274 { 275 final int read = IOUtils.readFully(in, metaData); 276 trackReadBytes(read); 277 if (read == 0) { 278 return null; 279 } 280 if (read < metaData.length) { 281 throw new IOException("Truncated ar archive"); 282 } 283 } 284 285 { 286 final byte[] expected = ArchiveUtils.toAsciiBytes(ArArchiveEntry.TRAILER); 287 final byte[] realized = IOUtils.readRange(in, expected.length); 288 final int read = realized.length; 289 trackReadBytes(read); 290 if (read != expected.length) { 291 throw new IOException("Failed to read entry trailer. Occurred at byte: " + getBytesRead()); 292 } 293 if (!Arrays.equals(expected, realized)) { 294 throw new IOException("Invalid entry trailer. not read the content? Occurred at byte: " + getBytesRead()); 295 } 296 } 297 298 entryOffset = offset; 299 300// GNU ar uses a '/' to mark the end of the file name; this allows for the use of spaces without the use of an extended file name. 301 302 // entry name is stored as ASCII string 303 String temp = ArchiveUtils.toAsciiString(metaData, NAME_OFFSET, NAME_LEN).trim(); 304 if (isGNUStringTable(temp)) { // GNU extended file names entry 305 currentEntry = readGNUStringTable(metaData, LENGTH_OFFSET, LENGTH_LEN); 306 return getNextArEntry(); 307 } 308 309 long len; 310 try { 311 len = asLong(metaData, LENGTH_OFFSET, LENGTH_LEN); 312 } catch (final NumberFormatException ex) { 313 throw new IOException("Broken archive, unable to parse ar_size field as a number", ex); 314 } 315 if (temp.endsWith("/")) { // GNU terminator 316 temp = temp.substring(0, temp.length() - 1); 317 } else if (isGNULongName(temp)) { 318 final int off = ParsingUtils.parseIntValue(temp.substring(1));// get the offset 319 temp = getExtendedName(off); // convert to the long name 320 } else if (isBSDLongName(temp)) { 321 temp = getBSDLongName(temp); 322 // entry length contained the length of the file name in 323 // addition to the real length of the entry. 324 // assume file name was ASCII, there is no "standard" otherwise 325 final int nameLen = temp.length(); 326 len -= nameLen; 327 entryOffset += nameLen; 328 } 329 330 if (len < 0) { 331 throw new IOException("broken archive, entry with negative size"); 332 } 333 334 try { 335 currentEntry = new ArArchiveEntry(temp, len, asInt(metaData, USER_ID_OFFSET, USER_ID_LEN, true), 336 asInt(metaData, GROUP_ID_OFFSET, GROUP_ID_LEN, true), asInt(metaData, FILE_MODE_OFFSET, FILE_MODE_LEN, 8), 337 asLong(metaData, LAST_MODIFIED_OFFSET, LAST_MODIFIED_LEN)); 338 return currentEntry; 339 } catch (final NumberFormatException ex) { 340 throw new IOException("Broken archive, unable to parse entry metadata fields as numbers", ex); 341 } 342 } 343 344 /* 345 * (non-Javadoc) 346 * 347 * @see org.apache.commons.compress.archivers.ArchiveInputStream#getNextEntry() 348 */ 349 @Override 350 public ArArchiveEntry getNextEntry() throws IOException { 351 return getNextArEntry(); 352 } 353 354 /** 355 * Does the name look like it is a long name (or a name containing spaces) as encoded by SVR4/GNU ar? 356 * 357 * @see #isGNUStringTable 358 */ 359 private boolean isGNULongName(final String name) { 360 return name != null && GNU_LONGNAME_PATTERN.matcher(name).matches(); 361 } 362 363 /* 364 * (non-Javadoc) 365 * 366 * @see java.io.InputStream#read(byte[], int, int) 367 */ 368 @Override 369 public int read(final byte[] b, final int off, final int len) throws IOException { 370 if (len == 0) { 371 return 0; 372 } 373 if (currentEntry == null) { 374 throw new IllegalStateException("No current ar entry"); 375 } 376 final long entryEnd = entryOffset + currentEntry.getLength(); 377 if (len < 0 || offset >= entryEnd) { 378 return -1; 379 } 380 final int toRead = (int) Math.min(len, entryEnd - offset); 381 final int ret = this.in.read(b, off, toRead); 382 trackReadBytes(ret); 383 return ret; 384 } 385 386 /** 387 * Reads the GNU archive String Table. 388 * 389 * @see #isGNUStringTable 390 */ 391 private ArArchiveEntry readGNUStringTable(final byte[] length, final int offset, final int len) throws IOException { 392 int bufflen; 393 try { 394 bufflen = asInt(length, offset, len); // Assume length will fit in an int 395 } catch (final NumberFormatException ex) { 396 throw new IOException("Broken archive, unable to parse GNU string table length field as a number", ex); 397 } 398 399 namebuffer = IOUtils.readRange(in, bufflen); 400 final int read = namebuffer.length; 401 trackReadBytes(read); 402 if (read != bufflen) { 403 throw new IOException("Failed to read complete // record: expected=" + bufflen + " read=" + read); 404 } 405 return new ArArchiveEntry(GNU_STRING_TABLE_NAME, bufflen); 406 } 407 408 private void trackReadBytes(final long read) { 409 count(read); 410 if (read > 0) { 411 offset += read; 412 } 413 } 414}