archival/libarchive/decompress_unlzma.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Small lzma deflate implementation.
   4  * Copyright (C) 2006  Aurelien Jacobs <aurel@gnuage.org>
   5  *
   6  * Based on LzmaDecode.c from the LZMA SDK 4.22 (http://www.7-zip.org/)
   7  * Copyright (C) 1999-2005  Igor Pavlov
   8  *
   9  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  10  */
  11 #include "libbb.h"
  12 #include "bb_archive.h"
  13
  14 #if ENABLE_FEATURE_LZMA_FAST
  15 #  define speed_inline ALWAYS_INLINE
  16 #  define size_inline
  17 #else
  18 #  define speed_inline
  19 #  define size_inline ALWAYS_INLINE
  20 #endif
  21
  22
  23 typedef struct {
  24         int fd;
  25         uint8_t *ptr;
  26
  27 /* Was keeping rc on stack in unlzma and separately allocating buffer,
  28  * but with "buffer 'attached to' allocated rc" code is smaller: */
  29         /* uint8_t *buffer; */
  30 #define RC_BUFFER ((uint8_t*)(rc+1))
  31
  32         uint8_t *buffer_end;
  33
  34 /* Had provisions for variable buffer, but we don't need it here */
  35         /* int buffer_size; */
  36 #define RC_BUFFER_SIZE 0x10000
  37
  38         uint32_t code;
  39         uint32_t range;
  40         uint32_t bound;
  41 } rc_t;
  42
  43 #define RC_TOP_BITS 24
  44 #define RC_MOVE_BITS 5
  45 #define RC_MODEL_TOTAL_BITS 11
  46
  47
  48 /* Called once in rc_do_normalize() */
  49 static void rc_read(rc_t *rc)
  50 {
  51         int buffer_size = safe_read(rc->fd, RC_BUFFER, RC_BUFFER_SIZE);
  52 //TODO: return -1 instead
  53 //This will make unlzma delete broken unpacked file on unpack errors
  54         if (buffer_size <= 0)
  55                 bb_error_msg_and_die("unexpected EOF");
  56         rc->buffer_end = RC_BUFFER + buffer_size;
  57         rc->ptr = RC_BUFFER;
  58 }
  59
  60 /* Called twice, but one callsite is in speed_inline'd rc_is_bit_1() */
  61 static void rc_do_normalize(rc_t *rc)
  62 {
  63         if (rc->ptr >= rc->buffer_end)
  64                 rc_read(rc);
  65         rc->range <<= 8;
  66         rc->code = (rc->code << 8) | *rc->ptr++;
  67 }
  68 static ALWAYS_INLINE void rc_normalize(rc_t *rc)
  69 {
  70         if (rc->range < (1 << RC_TOP_BITS)) {
  71                 rc_do_normalize(rc);
  72         }
  73 }
  74
  75 /* Called once */
  76 static ALWAYS_INLINE rc_t* rc_init(int fd) /*, int buffer_size) */
  77 {
  78         int i;
  79         rc_t *rc;
  80
  81         rc = xzalloc(sizeof(*rc) + RC_BUFFER_SIZE);
  82
  83         rc->fd = fd;
  84         /* rc->ptr = rc->buffer_end; */
  85
  86         for (i = 0; i < 5; i++) {
  87                 rc_do_normalize(rc);
  88         }
  89         rc->range = 0xffffffff;
  90         return rc;
  91 }
  92
  93 /* Called once  */
  94 static ALWAYS_INLINE void rc_free(rc_t *rc)
  95 {
  96         free(rc);
  97 }
  98
  99 /* rc_is_bit_1 is called 9 times */
 100 static speed_inline int rc_is_bit_1(rc_t *rc, uint16_t *p)
 101 {
 102         rc_normalize(rc);
 103         rc->bound = *p * (rc->range >> RC_MODEL_TOTAL_BITS);
 104         if (rc->code < rc->bound) {
 105                 rc->range = rc->bound;
 106                 *p += ((1 << RC_MODEL_TOTAL_BITS) - *p) >> RC_MOVE_BITS;
 107                 return 0;
 108         }
 109         rc->range -= rc->bound;
 110         rc->code -= rc->bound;
 111         *p -= *p >> RC_MOVE_BITS;
 112         return 1;
 113 }
 114
 115 /* Called 4 times in unlzma loop */
 116 static ALWAYS_INLINE int rc_get_bit(rc_t *rc, uint16_t *p, int *symbol)
 117 {
 118         int ret = rc_is_bit_1(rc, p);
 119         *symbol = *symbol * 2 + ret;
 120         return ret;
 121 }
 122
 123 /* Called once */
 124 static ALWAYS_INLINE int rc_direct_bit(rc_t *rc)
 125 {
 126         rc_normalize(rc);
 127         rc->range >>= 1;
 128         if (rc->code >= rc->range) {
 129                 rc->code -= rc->range;
 130                 return 1;
 131         }
 132         return 0;
 133 }
 134
 135 /* Called twice */
 136 static speed_inline void
 137 rc_bit_tree_decode(rc_t *rc, uint16_t *p, int num_levels, int *symbol)
 138 {
 139         int i = num_levels;
 140
 141         *symbol = 1;
 142         while (i--)
 143                 rc_get_bit(rc, p + *symbol, symbol);
 144         *symbol -= 1 << num_levels;
 145 }
 146
 147
 148 typedef struct {
 149         uint8_t pos;
 150         uint32_t dict_size;
 151         uint64_t dst_size;
 152 } PACKED lzma_header_t;
 153
 154
 155 /* #defines will force compiler to compute/optimize each one with each usage.
 156  * Have heart and use enum instead. */
 157 enum {
 158         LZMA_BASE_SIZE = 1846,
 159         LZMA_LIT_SIZE  = 768,
 160
 161         LZMA_NUM_POS_BITS_MAX = 4,
 162
 163         LZMA_LEN_NUM_LOW_BITS  = 3,
 164         LZMA_LEN_NUM_MID_BITS  = 3,
 165         LZMA_LEN_NUM_HIGH_BITS = 8,
 166
 167         LZMA_LEN_CHOICE     = 0,
 168         LZMA_LEN_CHOICE_2   = (LZMA_LEN_CHOICE + 1),
 169         LZMA_LEN_LOW        = (LZMA_LEN_CHOICE_2 + 1),
 170         LZMA_LEN_MID        = (LZMA_LEN_LOW \
 171                               + (1 << (LZMA_NUM_POS_BITS_MAX + LZMA_LEN_NUM_LOW_BITS))),
 172         LZMA_LEN_HIGH       = (LZMA_LEN_MID \
 173                               + (1 << (LZMA_NUM_POS_BITS_MAX + LZMA_LEN_NUM_MID_BITS))),
 174         LZMA_NUM_LEN_PROBS  = (LZMA_LEN_HIGH + (1 << LZMA_LEN_NUM_HIGH_BITS)),
 175
 176         LZMA_NUM_STATES     = 12,
 177         LZMA_NUM_LIT_STATES = 7,
 178
 179         LZMA_START_POS_MODEL_INDEX = 4,
 180         LZMA_END_POS_MODEL_INDEX   = 14,
 181         LZMA_NUM_FULL_DISTANCES    = (1 << (LZMA_END_POS_MODEL_INDEX >> 1)),
 182
 183         LZMA_NUM_POS_SLOT_BITS = 6,
 184         LZMA_NUM_LEN_TO_POS_STATES = 4,
 185
 186         LZMA_NUM_ALIGN_BITS = 4,
 187
 188         LZMA_MATCH_MIN_LEN  = 2,
 189
 190         LZMA_IS_MATCH       = 0,
 191         LZMA_IS_REP         = (LZMA_IS_MATCH + (LZMA_NUM_STATES << LZMA_NUM_POS_BITS_MAX)),
 192         LZMA_IS_REP_G0      = (LZMA_IS_REP + LZMA_NUM_STATES),
 193         LZMA_IS_REP_G1      = (LZMA_IS_REP_G0 + LZMA_NUM_STATES),
 194         LZMA_IS_REP_G2      = (LZMA_IS_REP_G1 + LZMA_NUM_STATES),
 195         LZMA_IS_REP_0_LONG  = (LZMA_IS_REP_G2 + LZMA_NUM_STATES),
 196         LZMA_POS_SLOT       = (LZMA_IS_REP_0_LONG \
 197                               + (LZMA_NUM_STATES << LZMA_NUM_POS_BITS_MAX)),
 198         LZMA_SPEC_POS       = (LZMA_POS_SLOT \
 199                               + (LZMA_NUM_LEN_TO_POS_STATES << LZMA_NUM_POS_SLOT_BITS)),
 200         LZMA_ALIGN          = (LZMA_SPEC_POS \
 201                               + LZMA_NUM_FULL_DISTANCES - LZMA_END_POS_MODEL_INDEX),
 202         LZMA_LEN_CODER      = (LZMA_ALIGN + (1 << LZMA_NUM_ALIGN_BITS)),
 203         LZMA_REP_LEN_CODER  = (LZMA_LEN_CODER + LZMA_NUM_LEN_PROBS),
 204         LZMA_LITERAL        = (LZMA_REP_LEN_CODER + LZMA_NUM_LEN_PROBS),
 205 };
 206
 207
 208 IF_DESKTOP(long long) int FAST_FUNC
 209 unpack_lzma_stream(transformer_state_t *xstate)
 210 {
 211         IF_DESKTOP(long long total_written = 0;)
 212         lzma_header_t header;
 213         int lc, pb, lp;
 214         uint32_t pos_state_mask;
 215         uint32_t literal_pos_mask;
 216         uint16_t *p;
 217         rc_t *rc;
 218         int i;
 219         uint8_t *buffer;
 220         uint8_t previous_byte = 0;
 221         size_t buffer_pos = 0, global_pos = 0;
 222         int len = 0;
 223         int state = 0;
 224         uint32_t rep0 = 1, rep1 = 1, rep2 = 1, rep3 = 1;
 225
 226         if (full_read(xstate->src_fd, &header, sizeof(header)) != sizeof(header)
 227          || header.pos >= (9 * 5 * 5)
 228         ) {
 229                 bb_error_msg("bad lzma header");
 230                 return -1;
 231         }
 232
 233         i = header.pos / 9;
 234         lc = header.pos % 9;
 235         pb = i / 5;
 236         lp = i % 5;
 237         pos_state_mask = (1 << pb) - 1;
 238         literal_pos_mask = (1 << lp) - 1;
 239
 240         /* Example values from linux-3.3.4.tar.lzma:
 241          * dict_size: 64M, dst_size: 2^64-1
 242          */
 243         header.dict_size = SWAP_LE32(header.dict_size);
 244         header.dst_size = SWAP_LE64(header.dst_size);
 245
 246         if (header.dict_size == 0)
 247                 header.dict_size++;
 248
 249         buffer = xmalloc(MIN(header.dst_size, header.dict_size));
 250
 251         {
 252                 int num_probs;
 253
 254                 num_probs = LZMA_BASE_SIZE + (LZMA_LIT_SIZE << (lc + lp));
 255                 p = xmalloc(num_probs * sizeof(*p));
 256                 num_probs += LZMA_LITERAL - LZMA_BASE_SIZE;
 257                 for (i = 0; i < num_probs; i++)
 258                         p[i] = (1 << RC_MODEL_TOTAL_BITS) >> 1;
 259         }
 260
 261         rc = rc_init(xstate->src_fd); /*, RC_BUFFER_SIZE); */
 262
 263         while (global_pos + buffer_pos < header.dst_size) {
 264                 int pos_state = (buffer_pos + global_pos) & pos_state_mask;
 265                 uint16_t *prob = p + LZMA_IS_MATCH + (state << LZMA_NUM_POS_BITS_MAX) + pos_state;
 266
 267                 if (!rc_is_bit_1(rc, prob)) {
 268                         static const char next_state[LZMA_NUM_STATES] =
 269                                 { 0, 0, 0, 0, 1, 2, 3, 4, 5, 6, 4, 5 };
 270                         int mi = 1;
 271
 272                         prob = (p + LZMA_LITERAL
 273                                 + (LZMA_LIT_SIZE * ((((buffer_pos + global_pos) & literal_pos_mask) << lc)
 274                                                     + (previous_byte >> (8 - lc))
 275                                                    )
 276                                   )
 277                         );
 278
 279                         if (state >= LZMA_NUM_LIT_STATES) {
 280                                 int match_byte;
 281                                 uint32_t pos;
 282
 283                                 pos = buffer_pos - rep0;
 284                                 if ((int32_t)pos < 0)
 285                                         pos += header.dict_size;
 286                                 match_byte = buffer[pos];
 287                                 do {
 288                                         int bit;
 289
 290                                         match_byte <<= 1;
 291                                         bit = match_byte & 0x100;
 292                                         bit ^= (rc_get_bit(rc, prob + 0x100 + bit + mi, &mi) << 8); /* 0x100 or 0 */
 293                                         if (bit)
 294                                                 break;
 295                                 } while (mi < 0x100);
 296                         }
 297                         while (mi < 0x100) {
 298                                 rc_get_bit(rc, prob + mi, &mi);
 299                         }
 300
 301                         state = next_state[state];
 302
 303                         previous_byte = (uint8_t) mi;
 304 #if ENABLE_FEATURE_LZMA_FAST
 305  one_byte1:
 306                         buffer[buffer_pos++] = previous_byte;
 307                         if (buffer_pos == header.dict_size) {
 308                                 buffer_pos = 0;
 309                                 global_pos += header.dict_size;
 310                                 if (transformer_write(xstate, buffer, header.dict_size) != (ssize_t)header.dict_size)
 311                                         goto bad;
 312                                 IF_DESKTOP(total_written += header.dict_size;)
 313                         }
 314 #else
 315                         len = 1;
 316                         goto one_byte2;
 317 #endif
 318                 } else {
 319                         int num_bits;
 320                         int offset;
 321                         uint16_t *prob2;
 322 #define prob_len prob2
 323
 324                         prob2 = p + LZMA_IS_REP + state;
 325                         if (!rc_is_bit_1(rc, prob2)) {
 326                                 rep3 = rep2;
 327                                 rep2 = rep1;
 328                                 rep1 = rep0;
 329                                 state = state < LZMA_NUM_LIT_STATES ? 0 : 3;
 330                                 prob2 = p + LZMA_LEN_CODER;
 331                         } else {
 332                                 prob2 += LZMA_IS_REP_G0 - LZMA_IS_REP;
 333                                 if (!rc_is_bit_1(rc, prob2)) {
 334                                         prob2 = (p + LZMA_IS_REP_0_LONG
 335                                                 + (state << LZMA_NUM_POS_BITS_MAX)
 336                                                 + pos_state
 337                                         );
 338                                         if (!rc_is_bit_1(rc, prob2)) {
 339 #if ENABLE_FEATURE_LZMA_FAST
 340                                                 uint32_t pos;
 341                                                 state = state < LZMA_NUM_LIT_STATES ? 9 : 11;
 342
 343                                                 pos = buffer_pos - rep0;
 344                                                 if ((int32_t)pos < 0)
 345                                                         pos += header.dict_size;
 346                                                 previous_byte = buffer[pos];
 347                                                 goto one_byte1;
 348 #else
 349                                                 state = state < LZMA_NUM_LIT_STATES ? 9 : 11;
 350                                                 len = 1;
 351                                                 goto string;
 352 #endif
 353                                         }
 354                                 } else {
 355                                         uint32_t distance;
 356
 357                                         prob2 += LZMA_IS_REP_G1 - LZMA_IS_REP_G0;
 358                                         distance = rep1;
 359                                         if (rc_is_bit_1(rc, prob2)) {
 360                                                 prob2 += LZMA_IS_REP_G2 - LZMA_IS_REP_G1;
 361                                                 distance = rep2;
 362                                                 if (rc_is_bit_1(rc, prob2)) {
 363                                                         distance = rep3;
 364                                                         rep3 = rep2;
 365                                                 }
 366                                                 rep2 = rep1;
 367                                         }
 368                                         rep1 = rep0;
 369                                         rep0 = distance;
 370                                 }
 371                                 state = state < LZMA_NUM_LIT_STATES ? 8 : 11;
 372                                 prob2 = p + LZMA_REP_LEN_CODER;
 373                         }
 374
 375                         prob_len = prob2 + LZMA_LEN_CHOICE;
 376                         num_bits = LZMA_LEN_NUM_LOW_BITS;
 377                         if (!rc_is_bit_1(rc, prob_len)) {
 378                                 prob_len += LZMA_LEN_LOW - LZMA_LEN_CHOICE
 379                                             + (pos_state << LZMA_LEN_NUM_LOW_BITS);
 380                                 offset = 0;
 381                         } else {
 382                                 prob_len += LZMA_LEN_CHOICE_2 - LZMA_LEN_CHOICE;
 383                                 if (!rc_is_bit_1(rc, prob_len)) {
 384                                         prob_len += LZMA_LEN_MID - LZMA_LEN_CHOICE_2
 385                                                     + (pos_state << LZMA_LEN_NUM_MID_BITS);
 386                                         offset = 1 << LZMA_LEN_NUM_LOW_BITS;
 387                                         num_bits += LZMA_LEN_NUM_MID_BITS - LZMA_LEN_NUM_LOW_BITS;
 388                                 } else {
 389                                         prob_len += LZMA_LEN_HIGH - LZMA_LEN_CHOICE_2;
 390                                         offset = ((1 << LZMA_LEN_NUM_LOW_BITS)
 391                                                   + (1 << LZMA_LEN_NUM_MID_BITS));
 392                                         num_bits += LZMA_LEN_NUM_HIGH_BITS - LZMA_LEN_NUM_LOW_BITS;
 393                                 }
 394                         }
 395                         rc_bit_tree_decode(rc, prob_len, num_bits, &len);
 396                         len += offset;
 397
 398                         if (state < 4) {
 399                                 int pos_slot;
 400                                 uint16_t *prob3;
 401
 402                                 state += LZMA_NUM_LIT_STATES;
 403                                 prob3 = p + LZMA_POS_SLOT +
 404                                        ((len < LZMA_NUM_LEN_TO_POS_STATES ? len :
 405                                          LZMA_NUM_LEN_TO_POS_STATES - 1)
 406                                          << LZMA_NUM_POS_SLOT_BITS);
 407                                 rc_bit_tree_decode(rc, prob3,
 408                                         LZMA_NUM_POS_SLOT_BITS, &pos_slot);
 409                                 rep0 = pos_slot;
 410                                 if (pos_slot >= LZMA_START_POS_MODEL_INDEX) {
 411                                         int i2, mi2, num_bits2 = (pos_slot >> 1) - 1;
 412                                         rep0 = 2 | (pos_slot & 1);
 413                                         if (pos_slot < LZMA_END_POS_MODEL_INDEX) {
 414                                                 rep0 <<= num_bits2;
 415                                                 prob3 = p + LZMA_SPEC_POS + rep0 - pos_slot - 1;
 416                                         } else {
 417                                                 for (; num_bits2 != LZMA_NUM_ALIGN_BITS; num_bits2--)
 418                                                         rep0 = (rep0 << 1) | rc_direct_bit(rc);
 419                                                 rep0 <<= LZMA_NUM_ALIGN_BITS;
 420                                                 prob3 = p + LZMA_ALIGN;
 421                                         }
 422                                         i2 = 1;
 423                                         mi2 = 1;
 424                                         while (num_bits2--) {
 425                                                 if (rc_get_bit(rc, prob3 + mi2, &mi2))
 426                                                         rep0 |= i2;
 427                                                 i2 <<= 1;
 428                                         }
 429                                 }
 430                                 if (++rep0 == 0)
 431                                         break;
 432                         }
 433
 434                         len += LZMA_MATCH_MIN_LEN;
 435                         /*
 436                          * LZMA SDK has this optimized:
 437                          * it precalculates size and copies many bytes
 438                          * in a loop with simpler checks, a-la:
 439                          *      do
 440                          *              *(dest) = *(dest + ofs);
 441                          *      while (++dest != lim);
 442                          * and
 443                          *      do {
 444                          *              buffer[buffer_pos++] = buffer[pos];
 445                          *              if (++pos == header.dict_size)
 446                          *                      pos = 0;
 447                          *      } while (--cur_len != 0);
 448                          * Our code is slower (more checks per byte copy):
 449                          */
 450  IF_NOT_FEATURE_LZMA_FAST(string:)
 451                         do {
 452                                 uint32_t pos = buffer_pos - rep0;
 453                                 if ((int32_t)pos < 0)
 454                                         pos += header.dict_size;
 455                                 previous_byte = buffer[pos];
 456  IF_NOT_FEATURE_LZMA_FAST(one_byte2:)
 457                                 buffer[buffer_pos++] = previous_byte;
 458                                 if (buffer_pos == header.dict_size) {
 459                                         buffer_pos = 0;
 460                                         global_pos += header.dict_size;
 461                                         if (transformer_write(xstate, buffer, header.dict_size) != (ssize_t)header.dict_size)
 462                                                 goto bad;
 463                                         IF_DESKTOP(total_written += header.dict_size;)
 464                                 }
 465                                 len--;
 466                         } while (len != 0 && buffer_pos < header.dst_size);
 467                         /* FIXME: ...........^^^^^
 468                          * shouldn't it be "global_pos + buffer_pos < header.dst_size"?
 469                          * It probably should, but it is a "do we accidentally
 470                          * unpack more bytes than expected?" check - which
 471                          * never happens for well-formed compression data...
 472                          */
 473                 }
 474         }
 475
 476         {
 477                 IF_NOT_DESKTOP(int total_written = 0; /* success */)
 478                 IF_DESKTOP(total_written += buffer_pos;)
 479                 if (transformer_write(xstate, buffer, buffer_pos) != (ssize_t)buffer_pos) {
 480  bad:
 481                         total_written = -1; /* failure */
 482                 }
 483                 rc_free(rc);
 484                 free(p);
 485                 free(buffer);
 486                 return total_written;
 487         }
 488 }