1 /* 2 * Copyright (C) 2007 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 // 18 // Misc zip/gzip utility functions. 19 // 20 21 #define LOG_TAG "ziputil" 22 23 #include <utils/Log.h> 24 #include <utils/ZipUtils.h> 25 #include <utils/ZipFileRO.h> 26 27 #include <stdlib.h> 28 #include <string.h> 29 #include <assert.h> 30 31 #include <zlib.h> 32 33 using namespace android; 34 35 /* 36 * Utility function that expands zip/gzip "deflate" compressed data 37 * into a buffer. 38 * 39 * "fd" is an open file positioned at the start of the "deflate" data 40 * "buf" must hold at least "uncompressedLen" bytes. 41 */ 42 /*static*/ bool ZipUtils::inflateToBuffer(int fd, void* buf, 43 long uncompressedLen, long compressedLen) 44 { 45 bool result = false; 46 const unsigned long kReadBufSize = 32768; 47 unsigned char* readBuf = NULL; 48 z_stream zstream; 49 int zerr; 50 unsigned long compRemaining; 51 52 assert(uncompressedLen >= 0); 53 assert(compressedLen >= 0); 54 55 readBuf = new unsigned char[kReadBufSize]; 56 if (readBuf == NULL) 57 goto bail; 58 compRemaining = compressedLen; 59 60 /* 61 * Initialize the zlib stream. 62 */ 63 memset(&zstream, 0, sizeof(zstream)); 64 zstream.zalloc = Z_NULL; 65 zstream.zfree = Z_NULL; 66 zstream.opaque = Z_NULL; 67 zstream.next_in = NULL; 68 zstream.avail_in = 0; 69 zstream.next_out = (Bytef*) buf; 70 zstream.avail_out = uncompressedLen; 71 zstream.data_type = Z_UNKNOWN; 72 73 /* 74 * Use the undocumented "negative window bits" feature to tell zlib 75 * that there's no zlib header waiting for it. 76 */ 77 zerr = inflateInit2(&zstream, -MAX_WBITS); 78 if (zerr != Z_OK) { 79 if (zerr == Z_VERSION_ERROR) { 80 ALOGE("Installed zlib is not compatible with linked version (%s)\n", 81 ZLIB_VERSION); 82 } else { 83 ALOGE("Call to inflateInit2 failed (zerr=%d)\n", zerr); 84 } 85 goto bail; 86 } 87 88 /* 89 * Loop while we have data. 90 */ 91 do { 92 unsigned long getSize; 93 94 /* read as much as we can */ 95 if (zstream.avail_in == 0) { 96 getSize = (compRemaining > kReadBufSize) ? 97 kReadBufSize : compRemaining; 98 ALOGV("+++ reading %ld bytes (%ld left)\n", 99 getSize, compRemaining); 100 101 int cc = read(fd, readBuf, getSize); 102 if (cc != (int) getSize) { 103 ALOGD("inflate read failed (%d vs %ld)\n", 104 cc, getSize); 105 goto z_bail; 106 } 107 108 compRemaining -= getSize; 109 110 zstream.next_in = readBuf; 111 zstream.avail_in = getSize; 112 } 113 114 /* uncompress the data */ 115 zerr = inflate(&zstream, Z_NO_FLUSH); 116 if (zerr != Z_OK && zerr != Z_STREAM_END) { 117 ALOGD("zlib inflate call failed (zerr=%d)\n", zerr); 118 goto z_bail; 119 } 120 121 /* output buffer holds all, so no need to write the output */ 122 } while (zerr == Z_OK); 123 124 assert(zerr == Z_STREAM_END); /* other errors should've been caught */ 125 126 if ((long) zstream.total_out != uncompressedLen) { 127 ALOGW("Size mismatch on inflated file (%ld vs %ld)\n", 128 zstream.total_out, uncompressedLen); 129 goto z_bail; 130 } 131 132 // success! 133 result = true; 134 135 z_bail: 136 inflateEnd(&zstream); /* free up any allocated structures */ 137 138 bail: 139 delete[] readBuf; 140 return result; 141 } 142 143 /* 144 * Utility function that expands zip/gzip "deflate" compressed data 145 * into a buffer. 146 * 147 * (This is a clone of the previous function, but it takes a FILE* instead 148 * of an fd. We could pass fileno(fd) to the above, but we can run into 149 * trouble when "fp" has a different notion of what fd's file position is.) 150 * 151 * "fp" is an open file positioned at the start of the "deflate" data 152 * "buf" must hold at least "uncompressedLen" bytes. 153 */ 154 /*static*/ bool ZipUtils::inflateToBuffer(FILE* fp, void* buf, 155 long uncompressedLen, long compressedLen) 156 { 157 bool result = false; 158 const unsigned long kReadBufSize = 32768; 159 unsigned char* readBuf = NULL; 160 z_stream zstream; 161 int zerr; 162 unsigned long compRemaining; 163 164 assert(uncompressedLen >= 0); 165 assert(compressedLen >= 0); 166 167 readBuf = new unsigned char[kReadBufSize]; 168 if (readBuf == NULL) 169 goto bail; 170 compRemaining = compressedLen; 171 172 /* 173 * Initialize the zlib stream. 174 */ 175 memset(&zstream, 0, sizeof(zstream)); 176 zstream.zalloc = Z_NULL; 177 zstream.zfree = Z_NULL; 178 zstream.opaque = Z_NULL; 179 zstream.next_in = NULL; 180 zstream.avail_in = 0; 181 zstream.next_out = (Bytef*) buf; 182 zstream.avail_out = uncompressedLen; 183 zstream.data_type = Z_UNKNOWN; 184 185 /* 186 * Use the undocumented "negative window bits" feature to tell zlib 187 * that there's no zlib header waiting for it. 188 */ 189 zerr = inflateInit2(&zstream, -MAX_WBITS); 190 if (zerr != Z_OK) { 191 if (zerr == Z_VERSION_ERROR) { 192 ALOGE("Installed zlib is not compatible with linked version (%s)\n", 193 ZLIB_VERSION); 194 } else { 195 ALOGE("Call to inflateInit2 failed (zerr=%d)\n", zerr); 196 } 197 goto bail; 198 } 199 200 /* 201 * Loop while we have data. 202 */ 203 do { 204 unsigned long getSize; 205 206 /* read as much as we can */ 207 if (zstream.avail_in == 0) { 208 getSize = (compRemaining > kReadBufSize) ? 209 kReadBufSize : compRemaining; 210 ALOGV("+++ reading %ld bytes (%ld left)\n", 211 getSize, compRemaining); 212 213 int cc = fread(readBuf, 1, getSize, fp); 214 if (cc != (int) getSize) { 215 ALOGD("inflate read failed (%d vs %ld)\n", 216 cc, getSize); 217 goto z_bail; 218 } 219 220 compRemaining -= getSize; 221 222 zstream.next_in = readBuf; 223 zstream.avail_in = getSize; 224 } 225 226 /* uncompress the data */ 227 zerr = inflate(&zstream, Z_NO_FLUSH); 228 if (zerr != Z_OK && zerr != Z_STREAM_END) { 229 ALOGD("zlib inflate call failed (zerr=%d)\n", zerr); 230 goto z_bail; 231 } 232 233 /* output buffer holds all, so no need to write the output */ 234 } while (zerr == Z_OK); 235 236 assert(zerr == Z_STREAM_END); /* other errors should've been caught */ 237 238 if ((long) zstream.total_out != uncompressedLen) { 239 ALOGW("Size mismatch on inflated file (%ld vs %ld)\n", 240 zstream.total_out, uncompressedLen); 241 goto z_bail; 242 } 243 244 // success! 245 result = true; 246 247 z_bail: 248 inflateEnd(&zstream); /* free up any allocated structures */ 249 250 bail: 251 delete[] readBuf; 252 return result; 253 } 254 255 /* 256 * Look at the contents of a gzip archive. We want to know where the 257 * data starts, and how long it will be after it is uncompressed. 258 * 259 * We expect to find the CRC and length as the last 8 bytes on the file. 260 * This is a pretty reasonable thing to expect for locally-compressed 261 * files, but there's a small chance that some extra padding got thrown 262 * on (the man page talks about compressed data written to tape). We 263 * don't currently deal with that here. If "gzip -l" whines, we're going 264 * to fail too. 265 * 266 * On exit, "fp" is pointing at the start of the compressed data. 267 */ 268 /*static*/ bool ZipUtils::examineGzip(FILE* fp, int* pCompressionMethod, 269 long* pUncompressedLen, long* pCompressedLen, unsigned long* pCRC32) 270 { 271 enum { // flags 272 FTEXT = 0x01, 273 FHCRC = 0x02, 274 FEXTRA = 0x04, 275 FNAME = 0x08, 276 FCOMMENT = 0x10, 277 }; 278 int ic; 279 int method, flags; 280 int i; 281 282 ic = getc(fp); 283 if (ic != 0x1f || getc(fp) != 0x8b) 284 return false; // not gzip 285 method = getc(fp); 286 flags = getc(fp); 287 288 /* quick sanity checks */ 289 if (method == EOF || flags == EOF) 290 return false; 291 if (method != ZipFileRO::kCompressDeflated) 292 return false; 293 294 /* skip over 4 bytes of mod time, 1 byte XFL, 1 byte OS */ 295 for (i = 0; i < 6; i++) 296 (void) getc(fp); 297 /* consume "extra" field, if present */ 298 if ((flags & FEXTRA) != 0) { 299 int len; 300 301 len = getc(fp); 302 len |= getc(fp) << 8; 303 while (len-- && getc(fp) != EOF) 304 ; 305 } 306 /* consume filename, if present */ 307 if ((flags & FNAME) != 0) { 308 do { 309 ic = getc(fp); 310 } while (ic != 0 && ic != EOF); 311 } 312 /* consume comment, if present */ 313 if ((flags & FCOMMENT) != 0) { 314 do { 315 ic = getc(fp); 316 } while (ic != 0 && ic != EOF); 317 } 318 /* consume 16-bit header CRC, if present */ 319 if ((flags & FHCRC) != 0) { 320 (void) getc(fp); 321 (void) getc(fp); 322 } 323 324 if (feof(fp) || ferror(fp)) 325 return false; 326 327 /* seek to the end; CRC and length are in the last 8 bytes */ 328 long curPosn = ftell(fp); 329 unsigned char buf[8]; 330 fseek(fp, -8, SEEK_END); 331 *pCompressedLen = ftell(fp) - curPosn; 332 333 if (fread(buf, 1, 8, fp) != 8) 334 return false; 335 /* seek back to start of compressed data */ 336 fseek(fp, curPosn, SEEK_SET); 337 338 *pCompressionMethod = method; 339 *pCRC32 = ZipFileRO::get4LE(&buf[0]); 340 *pUncompressedLen = ZipFileRO::get4LE(&buf[4]); 341 342 return true; 343 } 344
