archival/libarchive/decompress_unxz.c

   1 /*
   2  * This file uses XZ Embedded library code which is written
   3  * by Lasse Collin <lasse.collin@tukaani.org>
   4  * and Igor Pavlov <http://7-zip.org/>
   5  *
   6  * See README file in unxz/ directory for more information.
   7  *
   8  * This file is:
   9  * Copyright (C) 2010 Denys Vlasenko <vda.linux@googlemail.com>
  10  * Licensed under GPLv2, see file LICENSE in this source tree.
  11  */
  12 #include "libbb.h"
  13 #include "bb_archive.h"
  14
  15 #define XZ_FUNC FAST_FUNC
  16 #define XZ_EXTERN static
  17
  18 #define XZ_DEC_DYNALLOC
  19
  20 /* Skip check (rather than fail) of unsupported hash functions */
  21 #define XZ_DEC_ANY_CHECK  1
  22
  23 /* We use our own crc32 function */
  24 #define XZ_INTERNAL_CRC32 0
  25 static uint32_t xz_crc32(const uint8_t *buf, size_t size, uint32_t crc)
  26 {
  27         return ~crc32_block_endian0(~crc, buf, size, global_crc32_table);
  28 }
  29
  30 /* We use arch-optimized unaligned fixed-endian accessors.
  31  * They have been moved to libbb (proved to be useful elsewhere as well),
  32  * just check that we have them defined:
  33  */
  34 #if !defined(get_unaligned_le32) \
  35  || !defined(get_unaligned_be32) \
  36  || !defined(put_unaligned_le32) \
  37  || !defined(put_unaligned_be32)
  38 # error get_unaligned_le32 accessors are not defined
  39 #endif
  40 #define get_le32(p) (*(uint32_t*)(p))
  41
  42 #include "unxz/xz_dec_bcj.c"
  43 #include "unxz/xz_dec_lzma2.c"
  44 #include "unxz/xz_dec_stream.c"
  45
  46 IF_DESKTOP(long long) int FAST_FUNC
  47 unpack_xz_stream(transformer_state_t *xstate)
  48 {
  49         enum xz_ret xz_result;
  50         struct xz_buf iobuf;
  51         struct xz_dec *state;
  52         unsigned char *membuf;
  53         IF_DESKTOP(long long) int total = 0;
  54
  55         if (!global_crc32_table)
  56                 global_crc32_table = crc32_filltable(NULL, /*endian:*/ 0);
  57
  58         memset(&iobuf, 0, sizeof(iobuf));
  59         membuf = xmalloc(2 * BUFSIZ);
  60         iobuf.in = membuf;
  61         iobuf.out = membuf + BUFSIZ;
  62         iobuf.out_size = BUFSIZ;
  63
  64         if (!xstate || xstate->signature_skipped) {
  65                 /* Preload XZ file signature */
  66                 strcpy((char*)membuf, HEADER_MAGIC);
  67                 iobuf.in_size = HEADER_MAGIC_SIZE;
  68         } /* else: let xz code read & check it */
  69
  70         /* Limit memory usage to about 64 MiB. */
  71         state = xz_dec_init(XZ_DYNALLOC, 64*1024*1024);
  72
  73         xz_result = X_OK;
  74         while (1) {
  75                 if (iobuf.in_pos == iobuf.in_size) {
  76                         int rd = safe_read(xstate->src_fd, membuf, BUFSIZ);
  77                         if (rd < 0) {
  78                                 bb_error_msg(bb_msg_read_error);
  79                                 total = -1;
  80                                 break;
  81                         }
  82                         if (rd == 0 && xz_result == XZ_STREAM_END)
  83                                 break;
  84                         iobuf.in_size = rd;
  85                         iobuf.in_pos = 0;
  86                 }
  87                 if (xz_result == XZ_STREAM_END) {
  88                         /*
  89                          * Try to start decoding next concatenated stream.
  90                          * Stream padding must always be a multiple of four
  91                          * bytes to preserve four-byte alignment. To keep the
  92                          * code slightly smaller, we aren't as strict here as
  93                          * the .xz spec requires. We just skip all zero-bytes
  94                          * without checking the alignment and thus can accept
  95                          * files that aren't valid, e.g. the XZ utils test
  96                          * files bad-0pad-empty.xz and bad-0catpad-empty.xz.
  97                          */
  98                         do {
  99                                 if (membuf[iobuf.in_pos] != 0) {
 100                                         xz_dec_reset(state);
 101                                         goto do_run;
 102                                 }
 103                                 iobuf.in_pos++;
 104                         } while (iobuf.in_pos < iobuf.in_size);
 105                 }
 106  do_run:
 107 //              bb_error_msg(">in pos:%d size:%d out pos:%d size:%d",
 108 //                              iobuf.in_pos, iobuf.in_size, iobuf.out_pos, iobuf.out_size);
 109                 xz_result = xz_dec_run(state, &iobuf);
 110 //              bb_error_msg("<in pos:%d size:%d out pos:%d size:%d r:%d",
 111 //                              iobuf.in_pos, iobuf.in_size, iobuf.out_pos, iobuf.out_size, xz_result);
 112                 if (iobuf.out_pos) {
 113                         xtransformer_write(xstate, iobuf.out, iobuf.out_pos);
 114                         IF_DESKTOP(total += iobuf.out_pos;)
 115                         iobuf.out_pos = 0;
 116                 }
 117                 if (xz_result == XZ_STREAM_END) {
 118                         /*
 119                          * Can just "break;" here, if not for concatenated
 120                          * .xz streams.
 121                          * Checking for padding may require buffer
 122                          * replenishment. Can't do it here.
 123                          */
 124                         continue;
 125                 }
 126                 if (xz_result != XZ_OK && xz_result != XZ_UNSUPPORTED_CHECK) {
 127                         bb_error_msg("corrupted data");
 128                         total = -1;
 129                         break;
 130                 }
 131         }
 132
 133         xz_dec_end(state);
 134         free(membuf);
 135
 136         return total;
 137 }