1/*- 2 * Copyright (c) 2003-2007 Tim Kientzle 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR 15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 17 * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT, 18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 19 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 21 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 24 */ 25 26/* 27 * This code borrows heavily from "compress" source code, which is 28 * protected by the following copyright. (Clause 3 dropped by request 29 * of the Regents.) 30 */ 31 32/*- 33 * Copyright (c) 1985, 1986, 1992, 1993 34 * The Regents of the University of California. All rights reserved. 35 * 36 * This code is derived from software contributed to Berkeley by 37 * Diomidis Spinellis and James A. Woods, derived from original 38 * work by Spencer Thomas and Joseph Orost. 39 * 40 * Redistribution and use in source and binary forms, with or without 41 * modification, are permitted provided that the following conditions 42 * are met: 43 * 1. Redistributions of source code must retain the above copyright 44 * notice, this list of conditions and the following disclaimer. 45 * 2. Redistributions in binary form must reproduce the above copyright 46 * notice, this list of conditions and the following disclaimer in the 47 * documentation and/or other materials provided with the distribution. 48 * 4. Neither the name of the University nor the names of its contributors 49 * may be used to endorse or promote products derived from this software 50 * without specific prior written permission. 51 * 52 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 53 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 54 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 55 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 56 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 57 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 58 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 59 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 60 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 61 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 62 * SUCH DAMAGE. 63 */ 64 65 66#include "archive_platform.h" 67__FBSDID("$FreeBSD$"); 68 69#ifdef HAVE_ERRNO_H 70#include <errno.h> 71#endif 72#ifdef HAVE_STDLIB_H 73#include <stdlib.h> 74#endif 75#ifdef HAVE_STRING_H 76#include <string.h> 77#endif 78#ifdef HAVE_UNISTD_H 79#include <unistd.h> 80#endif 81 82#include "archive.h" 83#include "archive_private.h" 84#include "archive_read_private.h" 85 86/* 87 * Because LZW decompression is pretty simple, I've just implemented 88 * the whole decompressor here (cribbing from "compress" source code, 89 * of course), rather than relying on an external library. I have 90 * made an effort to clarify and simplify the algorithm, so the 91 * names and structure here don't exactly match those used by compress. 92 */ 93 94struct private_data { 95 /* Input variables. */ 96 const unsigned char *next_in; 97 size_t avail_in; 98 int bit_buffer; 99 int bits_avail; 100 size_t bytes_in_section; 101 102 /* Output variables. */ 103 size_t out_block_size; 104 void *out_block; 105 106 /* Decompression status variables. */ 107 int use_reset_code; 108 int end_of_stream; /* EOF status. */ 109 int maxcode; /* Largest code. */ 110 int maxcode_bits; /* Length of largest code. */ 111 int section_end_code; /* When to increase bits. */ 112 int bits; /* Current code length. */ 113 int oldcode; /* Previous code. */ 114 int finbyte; /* Last byte of prev code. */ 115 116 /* Dictionary. */ 117 int free_ent; /* Next dictionary entry. */ 118 unsigned char suffix[65536]; 119 uint16_t prefix[65536]; 120 121 /* 122 * Scratch area for expanding dictionary entries. Note: 123 * "worst" case here comes from compressing /dev/zero: the 124 * last code in the dictionary will code a sequence of 125 * 65536-256 zero bytes. Thus, we need stack space to expand 126 * a 65280-byte dictionary entry. (Of course, 32640:1 127 * compression could also be considered the "best" case. ;-) 128 */ 129 unsigned char *stackp; 130 unsigned char stack[65300]; 131}; 132 133static int compress_bidder_bid(struct archive_read_filter_bidder *, struct archive_read_filter *); 134static int compress_bidder_init(struct archive_read_filter *); 135static int compress_bidder_free(struct archive_read_filter_bidder *); 136 137static ssize_t compress_filter_read(struct archive_read_filter *, const void **); 138static int compress_filter_close(struct archive_read_filter *); 139 140static int getbits(struct archive_read_filter *, int n); 141static int next_code(struct archive_read_filter *); 142 143int 144archive_read_support_compression_compress(struct archive *_a) 145{ 146 struct archive_read *a = (struct archive_read *)_a; 147 struct archive_read_filter_bidder *bidder = __archive_read_get_bidder(a); 148 149 if (bidder == NULL) 150 return (ARCHIVE_FATAL); 151 152 bidder->data = NULL; 153 bidder->bid = compress_bidder_bid; 154 bidder->init = compress_bidder_init; 155 bidder->options = NULL; 156 bidder->free = compress_bidder_free; 157 return (ARCHIVE_OK); 158} 159 160/* 161 * Test whether we can handle this data. 162 * 163 * This logic returns zero if any part of the signature fails. It 164 * also tries to Do The Right Thing if a very short buffer prevents us 165 * from verifying as much as we would like. 166 */ 167static int 168compress_bidder_bid(struct archive_read_filter_bidder *self, 169 struct archive_read_filter *filter) 170{ 171 const unsigned char *buffer; 172 ssize_t avail; 173 int bits_checked; 174 175 (void)self; /* UNUSED */ 176 177 buffer = __archive_read_filter_ahead(filter, 2, &avail); 178 179 if (buffer == NULL) 180 return (0); 181 182 bits_checked = 0; 183 if (buffer[0] != 037) /* Verify first ID byte. */ 184 return (0); 185 bits_checked += 8; 186 187 if (buffer[1] != 0235) /* Verify second ID byte. */ 188 return (0); 189 bits_checked += 8; 190 191 /* 192 * TODO: Verify more. 193 */ 194 195 return (bits_checked); 196} 197 198/* 199 * Setup the callbacks. 200 */ 201static int 202compress_bidder_init(struct archive_read_filter *self) 203{ 204 struct private_data *state; 205 static const size_t out_block_size = 64 * 1024; 206 void *out_block; 207 int code; 208 209 self->code = ARCHIVE_COMPRESSION_COMPRESS; 210 self->name = "compress (.Z)"; 211 212 state = (struct private_data *)calloc(sizeof(*state), 1); 213 out_block = malloc(out_block_size); 214 if (state == NULL || out_block == NULL) { 215 free(out_block); 216 free(state); 217 archive_set_error(&self->archive->archive, ENOMEM, 218 "Can't allocate data for %s decompression", 219 self->name); 220 return (ARCHIVE_FATAL); 221 } 222 223 self->data = state; 224 state->out_block_size = out_block_size; 225 state->out_block = out_block; 226 self->read = compress_filter_read; 227 self->skip = NULL; /* not supported */ 228 self->close = compress_filter_close; 229 230 /* XXX MOVE THE FOLLOWING OUT OF INIT() XXX */ 231 232 (void)getbits(self, 8); /* Skip first signature byte. */ 233 (void)getbits(self, 8); /* Skip second signature byte. */ 234 235 code = getbits(self, 8); 236 state->maxcode_bits = code & 0x1f; 237 state->maxcode = (1 << state->maxcode_bits); 238 state->use_reset_code = code & 0x80; 239 240 /* Initialize decompressor. */ 241 state->free_ent = 256; 242 state->stackp = state->stack; 243 if (state->use_reset_code) 244 state->free_ent++; 245 state->bits = 9; 246 state->section_end_code = (1<<state->bits) - 1; 247 state->oldcode = -1; 248 for (code = 255; code >= 0; code--) { 249 state->prefix[code] = 0; 250 state->suffix[code] = code; 251 } 252 next_code(self); 253 254 return (ARCHIVE_OK); 255} 256 257/* 258 * Return a block of data from the decompression buffer. Decompress more 259 * as necessary. 260 */ 261static ssize_t 262compress_filter_read(struct archive_read_filter *self, const void **pblock) 263{ 264 struct private_data *state; 265 unsigned char *p, *start, *end; 266 int ret; 267 268 state = (struct private_data *)self->data; 269 if (state->end_of_stream) { 270 *pblock = NULL; 271 return (0); 272 } 273 p = start = (unsigned char *)state->out_block; 274 end = start + state->out_block_size; 275 276 while (p < end && !state->end_of_stream) { 277 if (state->stackp > state->stack) { 278 *p++ = *--state->stackp; 279 } else { 280 ret = next_code(self); 281 if (ret == -1) 282 state->end_of_stream = ret; 283 else if (ret != ARCHIVE_OK) 284 return (ret); 285 } 286 } 287 288 *pblock = start; 289 return (p - start); 290} 291 292/* 293 * Clean up the reader. 294 */ 295static int 296compress_bidder_free(struct archive_read_filter_bidder *self) 297{ 298 self->data = NULL; 299 return (ARCHIVE_OK); 300} 301 302/* 303 * Close and release the filter. 304 */ 305static int 306compress_filter_close(struct archive_read_filter *self) 307{ 308 struct private_data *state = (struct private_data *)self->data; 309 310 free(state->out_block); 311 free(state); 312 return (ARCHIVE_OK); 313} 314 315/* 316 * Process the next code and fill the stack with the expansion 317 * of the code. Returns ARCHIVE_FATAL if there is a fatal I/O or 318 * format error, ARCHIVE_EOF if we hit end of data, ARCHIVE_OK otherwise. 319 */ 320static int 321next_code(struct archive_read_filter *self) 322{ 323 struct private_data *state = (struct private_data *)self->data; 324 int code, newcode; 325 326 static int debug_buff[1024]; 327 static unsigned debug_index; 328 329 code = newcode = getbits(self, state->bits); 330 if (code < 0) 331 return (code); 332 333 debug_buff[debug_index++] = code; 334 if (debug_index >= sizeof(debug_buff)/sizeof(debug_buff[0])) 335 debug_index = 0; 336 337 /* If it's a reset code, reset the dictionary. */ 338 if ((code == 256) && state->use_reset_code) { 339 /* 340 * The original 'compress' implementation blocked its 341 * I/O in a manner that resulted in junk bytes being 342 * inserted after every reset. The next section skips 343 * this junk. (Yes, the number of *bytes* to skip is 344 * a function of the current *bit* length.) 345 */ 346 int skip_bytes = state->bits - 347 (state->bytes_in_section % state->bits); 348 skip_bytes %= state->bits; 349 state->bits_avail = 0; /* Discard rest of this byte. */ 350 while (skip_bytes-- > 0) { 351 code = getbits(self, 8); 352 if (code < 0) 353 return (code); 354 } 355 /* Now, actually do the reset. */ 356 state->bytes_in_section = 0; 357 state->bits = 9; 358 state->section_end_code = (1 << state->bits) - 1; 359 state->free_ent = 257; 360 state->oldcode = -1; 361 return (next_code(self)); 362 } 363 364 if (code > state->free_ent) { 365 /* An invalid code is a fatal error. */ 366 archive_set_error(&(self->archive->archive), -1, 367 "Invalid compressed data"); 368 return (ARCHIVE_FATAL); 369 } 370 371 /* Special case for KwKwK string. */ 372 if (code >= state->free_ent) { 373 *state->stackp++ = state->finbyte; 374 code = state->oldcode; 375 } 376 377 /* Generate output characters in reverse order. */ 378 while (code >= 256) { 379 *state->stackp++ = state->suffix[code]; 380 code = state->prefix[code]; 381 } 382 *state->stackp++ = state->finbyte = code; 383 384 /* Generate the new entry. */ 385 code = state->free_ent; 386 if (code < state->maxcode && state->oldcode >= 0) { 387 state->prefix[code] = state->oldcode; 388 state->suffix[code] = state->finbyte; 389 ++state->free_ent; 390 } 391 if (state->free_ent > state->section_end_code) { 392 state->bits++; 393 state->bytes_in_section = 0; 394 if (state->bits == state->maxcode_bits) 395 state->section_end_code = state->maxcode; 396 else 397 state->section_end_code = (1 << state->bits) - 1; 398 } 399 400 /* Remember previous code. */ 401 state->oldcode = newcode; 402 return (ARCHIVE_OK); 403} 404 405/* 406 * Return next 'n' bits from stream. 407 * 408 * -1 indicates end of available data. 409 */ 410static int 411getbits(struct archive_read_filter *self, int n) 412{ 413 struct private_data *state = (struct private_data *)self->data; 414 int code; 415 ssize_t ret; 416 static const int mask[] = { 417 0x00, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f, 0xff, 418 0x1ff, 0x3ff, 0x7ff, 0xfff, 0x1fff, 0x3fff, 0x7fff, 0xffff 419 }; 420 421 while (state->bits_avail < n) { 422 if (state->avail_in <= 0) { 423 state->next_in 424 = __archive_read_filter_ahead(self->upstream, 425 1, &ret); 426 if (ret == 0) 427 return (-1); 428 if (ret < 0 || state->next_in == NULL) 429 return (ARCHIVE_FATAL); 430 state->avail_in = ret; 431 __archive_read_filter_consume(self->upstream, ret); 432 } 433 state->bit_buffer |= *state->next_in++ << state->bits_avail; 434 state->avail_in--; 435 state->bits_avail += 8; 436 state->bytes_in_section++; 437 } 438 439 code = state->bit_buffer; 440 state->bit_buffer >>= n; 441 state->bits_avail -= n; 442 443 return (code & mask[n]); 444} 445