1 /////////////////////////////////////////////////////////////////////////////// 2 // 3 /// \file coder.c 4 /// \brief Compresses or uncompresses a file 5 // 6 // Author: Lasse Collin 7 // 8 // This file has been put into the public domain. 9 // You can do whatever you want with this file. 10 // 11 /////////////////////////////////////////////////////////////////////////////// 12 13 #include "private.h" 14 15 16 /// Return value type for coder_init(). 17 enum coder_init_ret { 18 CODER_INIT_NORMAL, 19 CODER_INIT_PASSTHRU, 20 CODER_INIT_ERROR, 21 }; 22 23 24 enum operation_mode opt_mode = MODE_COMPRESS; 25 enum format_type opt_format = FORMAT_AUTO; 26 bool opt_auto_adjust = true; 27 28 29 /// Stream used to communicate with liblzma 30 static lzma_stream strm = LZMA_STREAM_INIT; 31 32 /// Filters needed for all encoding all formats, and also decoding in raw data 33 static lzma_filter filters[LZMA_FILTERS_MAX + 1]; 34 35 /// Input and output buffers 36 static io_buf in_buf; 37 static io_buf out_buf; 38 39 /// Number of filters. Zero indicates that we are using a preset. 40 static size_t filters_count = 0; 41 42 /// Number of the preset (0-9) 43 static size_t preset_number = 6; 44 45 /// If a preset is used (no custom filter chain) and preset_extreme is true, 46 /// a significantly slower compression is used to achieve slightly better 47 /// compression ratio. 48 static bool preset_extreme = false; 49 50 /// Integrity check type 51 static lzma_check check; 52 53 /// This becomes false if the --check=CHECK option is used. 54 static bool check_default = true; 55 56 57 extern void 58 coder_set_check(lzma_check new_check) 59 { 60 check = new_check; 61 check_default = false; 62 return; 63 } 64 65 66 extern void 67 coder_set_preset(size_t new_preset) 68 { 69 preset_number = new_preset; 70 71 // Setting a preset makes us forget a possibly defined custom 72 // filter chain. 73 while (filters_count > 0) { 74 --filters_count; 75 free(filters[filters_count].options); 76 filters[filters_count].options = NULL; 77 } 78 79 return; 80 } 81 82 83 extern void 84 coder_set_extreme(void) 85 { 86 preset_extreme = true; 87 return; 88 } 89 90 91 extern void 92 coder_add_filter(lzma_vli id, void *options) 93 { 94 if (filters_count == LZMA_FILTERS_MAX) 95 message_fatal(_("Maximum number of filters is four")); 96 97 filters[filters_count].id = id; 98 filters[filters_count].options = options; 99 ++filters_count; 100 101 return; 102 } 103 104 105 static void lzma_attribute((noreturn)) 106 memlimit_too_small(uint64_t memory_usage) 107 { 108 message(V_ERROR, _("Memory usage limit is too low for the given " 109 "filter setup.")); 110 message_mem_needed(V_ERROR, memory_usage); 111 tuklib_exit(E_ERROR, E_ERROR, false); 112 } 113 114 115 extern void 116 coder_set_compression_settings(void) 117 { 118 // Options for LZMA1 or LZMA2 in case we are using a preset. 119 static lzma_options_lzma opt_lzma; 120 121 if (filters_count == 0) { 122 // We are using a preset. This is not a good idea in raw mode 123 // except when playing around with things. Different versions 124 // of this software may use different options in presets, and 125 // thus make uncompressing the raw data difficult. 126 if (opt_format == FORMAT_RAW) { 127 // The message is shown only if warnings are allowed 128 // but the exit status isn't changed. 129 message(V_WARNING, _("Using a preset in raw mode " 130 "is discouraged.")); 131 message(V_WARNING, _("The exact options of the " 132 "presets may vary between software " 133 "versions.")); 134 } 135 136 // Get the preset for LZMA1 or LZMA2. 137 if (preset_extreme) 138 preset_number |= LZMA_PRESET_EXTREME; 139 140 if (lzma_lzma_preset(&opt_lzma, preset_number)) 141 message_bug(); 142 143 // Use LZMA2 except with --format=lzma we use LZMA1. 144 filters[0].id = opt_format == FORMAT_LZMA 145 ? LZMA_FILTER_LZMA1 : LZMA_FILTER_LZMA2; 146 filters[0].options = &opt_lzma; 147 filters_count = 1; 148 } 149 150 // Terminate the filter options array. 151 filters[filters_count].id = LZMA_VLI_UNKNOWN; 152 153 // If we are using the .lzma format, allow exactly one filter 154 // which has to be LZMA1. 155 if (opt_format == FORMAT_LZMA && (filters_count != 1 156 || filters[0].id != LZMA_FILTER_LZMA1)) 157 message_fatal(_("The .lzma format supports only " 158 "the LZMA1 filter")); 159 160 // If we are using the .xz format, make sure that there is no LZMA1 161 // filter to prevent LZMA_PROG_ERROR. 162 if (opt_format == FORMAT_XZ) 163 for (size_t i = 0; i < filters_count; ++i) 164 if (filters[i].id == LZMA_FILTER_LZMA1) 165 message_fatal(_("LZMA1 cannot be used " 166 "with the .xz format")); 167 168 // Print the selected filter chain. 169 message_filters_show(V_DEBUG, filters); 170 171 // If using --format=raw, we can be decoding. The memusage function 172 // also validates the filter chain and the options used for the 173 // filters. 174 const uint64_t memory_limit = hardware_memlimit_get(opt_mode); 175 uint64_t memory_usage; 176 if (opt_mode == MODE_COMPRESS) 177 memory_usage = lzma_raw_encoder_memusage(filters); 178 else 179 memory_usage = lzma_raw_decoder_memusage(filters); 180 181 if (memory_usage == UINT64_MAX) 182 message_fatal(_("Unsupported filter chain or filter options")); 183 184 // Print memory usage info before possible dictionary 185 // size auto-adjusting. 186 message_mem_needed(V_DEBUG, memory_usage); 187 if (opt_mode == MODE_COMPRESS) { 188 const uint64_t decmem = lzma_raw_decoder_memusage(filters); 189 if (decmem != UINT64_MAX) 190 message(V_DEBUG, _("Decompression will need " 191 "%s MiB of memory."), uint64_to_str( 192 round_up_to_mib(decmem), 0)); 193 } 194 195 if (memory_usage > memory_limit) { 196 // If --no-auto-adjust was used or we didn't find LZMA1 or 197 // LZMA2 as the last filter, give an error immediately. 198 // --format=raw implies --no-auto-adjust. 199 if (!opt_auto_adjust || opt_format == FORMAT_RAW) 200 memlimit_too_small(memory_usage); 201 202 assert(opt_mode == MODE_COMPRESS); 203 204 // Look for the last filter if it is LZMA2 or LZMA1, so 205 // we can make it use less RAM. With other filters we don't 206 // know what to do. 207 size_t i = 0; 208 while (filters[i].id != LZMA_FILTER_LZMA2 209 && filters[i].id != LZMA_FILTER_LZMA1) { 210 if (filters[i].id == LZMA_VLI_UNKNOWN) 211 memlimit_too_small(memory_usage); 212 213 ++i; 214 } 215 216 // Decrease the dictionary size until we meet the memory 217 // usage limit. First round down to full mebibytes. 218 lzma_options_lzma *opt = filters[i].options; 219 const uint32_t orig_dict_size = opt->dict_size; 220 opt->dict_size &= ~((UINT32_C(1) << 20) - 1); 221 while (true) { 222 // If it is below 1 MiB, auto-adjusting failed. We 223 // could be more sophisticated and scale it down even 224 // more, but let's see if many complain about this 225 // version. 226 // 227 // FIXME: Displays the scaled memory usage instead 228 // of the original. 229 if (opt->dict_size < (UINT32_C(1) << 20)) 230 memlimit_too_small(memory_usage); 231 232 memory_usage = lzma_raw_encoder_memusage(filters); 233 if (memory_usage == UINT64_MAX) 234 message_bug(); 235 236 // Accept it if it is low enough. 237 if (memory_usage <= memory_limit) 238 break; 239 240 // Otherwise 1 MiB down and try again. I hope this 241 // isn't too slow method for cases where the original 242 // dict_size is very big. 243 opt->dict_size -= UINT32_C(1) << 20; 244 } 245 246 // Tell the user that we decreased the dictionary size. 247 message(V_WARNING, _("Adjusted LZMA%c dictionary size " 248 "from %s MiB to %s MiB to not exceed " 249 "the memory usage limit of %s MiB"), 250 filters[i].id == LZMA_FILTER_LZMA2 251 ? '2' : '1', 252 uint64_to_str(orig_dict_size >> 20, 0), 253 uint64_to_str(opt->dict_size >> 20, 1), 254 uint64_to_str(round_up_to_mib( 255 memory_limit), 2)); 256 } 257 258 /* 259 // Limit the number of worker threads so that memory usage 260 // limit isn't exceeded. 261 assert(memory_usage > 0); 262 size_t thread_limit = memory_limit / memory_usage; 263 if (thread_limit == 0) 264 thread_limit = 1; 265 266 if (opt_threads > thread_limit) 267 opt_threads = thread_limit; 268 */ 269 270 if (check_default) { 271 // The default check type is CRC64, but fallback to CRC32 272 // if CRC64 isn't supported by the copy of liblzma we are 273 // using. CRC32 is always supported. 274 check = LZMA_CHECK_CRC64; 275 if (!lzma_check_is_supported(check)) 276 check = LZMA_CHECK_CRC32; 277 } 278 279 return; 280 } 281 282 283 /// Return true if the data in in_buf seems to be in the .xz format. 284 static bool 285 is_format_xz(void) 286 { 287 return strm.avail_in >= 6 && memcmp(in_buf.u8, "\3757zXZ", 6) == 0; 288 } 289 290 291 /// Return true if the data in in_buf seems to be in the .lzma format. 292 static bool 293 is_format_lzma(void) 294 { 295 // The .lzma header is 13 bytes. 296 if (strm.avail_in < 13) 297 return false; 298 299 // Decode the LZMA1 properties. 300 lzma_filter filter = { .id = LZMA_FILTER_LZMA1 }; 301 if (lzma_properties_decode(&filter, NULL, in_buf.u8, 5) != LZMA_OK) 302 return false; 303 304 // A hack to ditch tons of false positives: We allow only dictionary 305 // sizes that are 2^n or 2^n + 2^(n-1) or UINT32_MAX. LZMA_Alone 306 // created only files with 2^n, but accepts any dictionary size. 307 // If someone complains, this will be reconsidered. 308 lzma_options_lzma *opt = filter.options; 309 const uint32_t dict_size = opt->dict_size; 310 free(opt); 311 312 if (dict_size != UINT32_MAX) { 313 uint32_t d = dict_size - 1; 314 d |= d >> 2; 315 d |= d >> 3; 316 d |= d >> 4; 317 d |= d >> 8; 318 d |= d >> 16; 319 ++d; 320 if (d != dict_size || dict_size == 0) 321 return false; 322 } 323 324 // Another hack to ditch false positives: Assume that if the 325 // uncompressed size is known, it must be less than 256 GiB. 326 // Again, if someone complains, this will be reconsidered. 327 uint64_t uncompressed_size = 0; 328 for (size_t i = 0; i < 8; ++i) 329 uncompressed_size |= (uint64_t)(in_buf.u8[5 + i]) << (i * 8); 330 331 if (uncompressed_size != UINT64_MAX 332 && uncompressed_size > (UINT64_C(1) << 38)) 333 return false; 334 335 return true; 336 } 337 338 339 /// Detect the input file type (for now, this done only when decompressing), 340 /// and initialize an appropriate coder. Return value indicates if a normal 341 /// liblzma-based coder was initialized (CODER_INIT_NORMAL), if passthru 342 /// mode should be used (CODER_INIT_PASSTHRU), or if an error occurred 343 /// (CODER_INIT_ERROR). 344 static enum coder_init_ret 345 coder_init(file_pair *pair) 346 { 347 lzma_ret ret = LZMA_PROG_ERROR; 348 349 if (opt_mode == MODE_COMPRESS) { 350 switch (opt_format) { 351 case FORMAT_AUTO: 352 // args.c ensures this. 353 assert(0); 354 break; 355 356 case FORMAT_XZ: 357 ret = lzma_stream_encoder(&strm, filters, check); 358 break; 359 360 case FORMAT_LZMA: 361 ret = lzma_alone_encoder(&strm, filters[0].options); 362 break; 363 364 case FORMAT_RAW: 365 ret = lzma_raw_encoder(&strm, filters); 366 break; 367 } 368 } else { 369 const uint32_t flags = LZMA_TELL_UNSUPPORTED_CHECK 370 | LZMA_CONCATENATED; 371 372 // We abuse FORMAT_AUTO to indicate unknown file format, 373 // for which we may consider passthru mode. 374 enum format_type init_format = FORMAT_AUTO; 375 376 switch (opt_format) { 377 case FORMAT_AUTO: 378 if (is_format_xz()) 379 init_format = FORMAT_XZ; 380 else if (is_format_lzma()) 381 init_format = FORMAT_LZMA; 382 break; 383 384 case FORMAT_XZ: 385 if (is_format_xz()) 386 init_format = FORMAT_XZ; 387 break; 388 389 case FORMAT_LZMA: 390 if (is_format_lzma()) 391 init_format = FORMAT_LZMA; 392 break; 393 394 case FORMAT_RAW: 395 init_format = FORMAT_RAW; 396 break; 397 } 398 399 switch (init_format) { 400 case FORMAT_AUTO: 401 // Uknown file format. If --decompress --stdout 402 // --force have been given, then we copy the input 403 // as is to stdout. Checking for MODE_DECOMPRESS 404 // is needed, because we don't want to do use 405 // passthru mode with --test. 406 if (opt_mode == MODE_DECOMPRESS 407 && opt_stdout && opt_force) 408 return CODER_INIT_PASSTHRU; 409 410 ret = LZMA_FORMAT_ERROR; 411 break; 412 413 case FORMAT_XZ: 414 ret = lzma_stream_decoder(&strm, 415 hardware_memlimit_get( 416 MODE_DECOMPRESS), flags); 417 break; 418 419 case FORMAT_LZMA: 420 ret = lzma_alone_decoder(&strm, 421 hardware_memlimit_get( 422 MODE_DECOMPRESS)); 423 break; 424 425 case FORMAT_RAW: 426 // Memory usage has already been checked in 427 // coder_set_compression_settings(). 428 ret = lzma_raw_decoder(&strm, filters); 429 break; 430 } 431 432 // Try to decode the headers. This will catch too low 433 // memory usage limit in case it happens in the first 434 // Block of the first Stream, which is where it very 435 // probably will happen if it is going to happen. 436 if (ret == LZMA_OK && init_format != FORMAT_RAW) { 437 strm.next_out = NULL; 438 strm.avail_out = 0; 439 ret = lzma_code(&strm, LZMA_RUN); 440 } 441 } 442 443 if (ret != LZMA_OK) { 444 message_error("%s: %s", pair->src_name, message_strm(ret)); 445 if (ret == LZMA_MEMLIMIT_ERROR) 446 message_mem_needed(V_ERROR, lzma_memusage(&strm)); 447 448 return CODER_INIT_ERROR; 449 } 450 451 return CODER_INIT_NORMAL; 452 } 453 454 455 /// Compress or decompress using liblzma. 456 static bool 457 coder_normal(file_pair *pair) 458 { 459 // Encoder needs to know when we have given all the input to it. 460 // The decoders need to know it too when we are using 461 // LZMA_CONCATENATED. We need to check for src_eof here, because 462 // the first input chunk has been already read, and that may 463 // have been the only chunk we will read. 464 lzma_action action = pair->src_eof ? LZMA_FINISH : LZMA_RUN; 465 466 lzma_ret ret; 467 468 // Assume that something goes wrong. 469 bool success = false; 470 471 strm.next_out = out_buf.u8; 472 strm.avail_out = IO_BUFFER_SIZE; 473 474 while (!user_abort) { 475 // Fill the input buffer if it is empty and we haven't reached 476 // end of file yet. 477 if (strm.avail_in == 0 && !pair->src_eof) { 478 strm.next_in = in_buf.u8; 479 strm.avail_in = io_read( 480 pair, &in_buf, IO_BUFFER_SIZE); 481 482 if (strm.avail_in == SIZE_MAX) 483 break; 484 485 if (pair->src_eof) 486 action = LZMA_FINISH; 487 } 488 489 // Let liblzma do the actual work. 490 ret = lzma_code(&strm, action); 491 492 // Write out if the output buffer became full. 493 if (strm.avail_out == 0) { 494 if (opt_mode != MODE_TEST && io_write(pair, &out_buf, 495 IO_BUFFER_SIZE - strm.avail_out)) 496 break; 497 498 strm.next_out = out_buf.u8; 499 strm.avail_out = IO_BUFFER_SIZE; 500 } 501 502 if (ret != LZMA_OK) { 503 // Determine if the return value indicates that we 504 // won't continue coding. 505 const bool stop = ret != LZMA_NO_CHECK 506 && ret != LZMA_UNSUPPORTED_CHECK; 507 508 if (stop) { 509 // Write the remaining bytes even if something 510 // went wrong, because that way the user gets 511 // as much data as possible, which can be good 512 // when trying to get at least some useful 513 // data out of damaged files. 514 if (opt_mode != MODE_TEST && io_write(pair, 515 &out_buf, IO_BUFFER_SIZE 516 - strm.avail_out)) 517 break; 518 } 519 520 if (ret == LZMA_STREAM_END) { 521 // Check that there is no trailing garbage. 522 // This is needed for LZMA_Alone and raw 523 // streams. 524 if (strm.avail_in == 0 && !pair->src_eof) { 525 // Try reading one more byte. 526 // Hopefully we don't get any more 527 // input, and thus pair->src_eof 528 // becomes true. 529 strm.avail_in = io_read( 530 pair, &in_buf, 1); 531 if (strm.avail_in == SIZE_MAX) 532 break; 533 534 assert(strm.avail_in == 0 535 || strm.avail_in == 1); 536 } 537 538 if (strm.avail_in == 0) { 539 assert(pair->src_eof); 540 success = true; 541 break; 542 } 543 544 // We hadn't reached the end of the file. 545 ret = LZMA_DATA_ERROR; 546 assert(stop); 547 } 548 549 // If we get here and stop is true, something went 550 // wrong and we print an error. Otherwise it's just 551 // a warning and coding can continue. 552 if (stop) { 553 message_error("%s: %s", pair->src_name, 554 message_strm(ret)); 555 } else { 556 message_warning("%s: %s", pair->src_name, 557 message_strm(ret)); 558 559 // When compressing, all possible errors set 560 // stop to true. 561 assert(opt_mode != MODE_COMPRESS); 562 } 563 564 if (ret == LZMA_MEMLIMIT_ERROR) { 565 // Display how much memory it would have 566 // actually needed. 567 message_mem_needed(V_ERROR, 568 lzma_memusage(&strm)); 569 } 570 571 if (stop) 572 break; 573 } 574 575 // Show progress information under certain conditions. 576 message_progress_update(); 577 } 578 579 return success; 580 } 581 582 583 /// Copy from input file to output file without processing the data in any 584 /// way. This is used only when trying to decompress unrecognized files 585 /// with --decompress --stdout --force, so the output is always stdout. 586 static bool 587 coder_passthru(file_pair *pair) 588 { 589 while (strm.avail_in != 0) { 590 if (user_abort) 591 return false; 592 593 if (io_write(pair, &in_buf, strm.avail_in)) 594 return false; 595 596 strm.total_in += strm.avail_in; 597 strm.total_out = strm.total_in; 598 message_progress_update(); 599 600 strm.avail_in = io_read(pair, &in_buf, IO_BUFFER_SIZE); 601 if (strm.avail_in == SIZE_MAX) 602 return false; 603 } 604 605 return true; 606 } 607 608 609 extern void 610 coder_run(const char *filename) 611 { 612 // Set and possibly print the filename for the progress message. 613 message_filename(filename); 614 615 // Try to open the input file. 616 file_pair *pair = io_open_src(filename); 617 if (pair == NULL) 618 return; 619 620 // Assume that something goes wrong. 621 bool success = false; 622 623 // Read the first chunk of input data. This is needed to detect 624 // the input file type (for now, only for decompression). 625 strm.next_in = in_buf.u8; 626 strm.avail_in = io_read(pair, &in_buf, IO_BUFFER_SIZE); 627 628 if (strm.avail_in != SIZE_MAX) { 629 // Initialize the coder. This will detect the file format 630 // and, in decompression or testing mode, check the memory 631 // usage of the first Block too. This way we don't try to 632 // open the destination file if we see that coding wouldn't 633 // work at all anyway. This also avoids deleting the old 634 // "target" file if --force was used. 635 const enum coder_init_ret init_ret = coder_init(pair); 636 637 if (init_ret != CODER_INIT_ERROR && !user_abort) { 638 // Don't open the destination file when --test 639 // is used. 640 if (opt_mode == MODE_TEST || !io_open_dest(pair)) { 641 // Initialize the progress indicator. 642 const uint64_t in_size 643 = pair->src_st.st_size <= 0 644 ? 0 : pair->src_st.st_size; 645 message_progress_start(&strm, in_size); 646 647 // Do the actual coding or passthru. 648 if (init_ret == CODER_INIT_NORMAL) 649 success = coder_normal(pair); 650 else 651 success = coder_passthru(pair); 652 653 message_progress_end(success); 654 } 655 } 656 } 657 658 // Close the file pair. It needs to know if coding was successful to 659 // know if the source or target file should be unlinked. 660 io_close(pair, success); 661 662 return; 663 } 664