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      1 
      2 /* A test program written to test robustness to decompression of
      3    corrupted data.  Usage is
      4        unzcrash filename
      5    and the program will read the specified file, compress it (in memory),
      6    and then repeatedly decompress it, each time with a different bit of
      7    the compressed data inverted, so as to test all possible one-bit errors.
      8    This should not cause any invalid memory accesses.  If it does,
      9    I want to know about it!
     10 
     11    PS.  As you can see from the above description, the process is
     12    incredibly slow.  A file of size eg 5KB will cause it to run for
     13    many hours.
     14 */
     15 
     16 /* ------------------------------------------------------------------
     17    This file is part of bzip2/libbzip2, a program and library for
     18    lossless, block-sorting data compression.
     19 
     20    bzip2/libbzip2 version 1.0.6 of 6 September 2010
     21    Copyright (C) 1996-2010 Julian Seward <jseward (at) bzip.org>
     22 
     23    Please read the WARNING, DISCLAIMER and PATENTS sections in the
     24    README file.
     25 
     26    This program is released under the terms of the license contained
     27    in the file LICENSE.
     28    ------------------------------------------------------------------ */
     29 
     30 
     31 #include <stdio.h>
     32 #include <assert.h>
     33 #include "bzlib.h"
     34 
     35 #define M_BLOCK 1000000
     36 
     37 typedef unsigned char uchar;
     38 
     39 #define M_BLOCK_OUT (M_BLOCK + 1000000)
     40 uchar inbuf[M_BLOCK];
     41 uchar outbuf[M_BLOCK_OUT];
     42 uchar zbuf[M_BLOCK + 600 + (M_BLOCK / 100)];
     43 
     44 int nIn, nOut, nZ;
     45 
     46 static char *bzerrorstrings[] = {
     47        "OK"
     48       ,"SEQUENCE_ERROR"
     49       ,"PARAM_ERROR"
     50       ,"MEM_ERROR"
     51       ,"DATA_ERROR"
     52       ,"DATA_ERROR_MAGIC"
     53       ,"IO_ERROR"
     54       ,"UNEXPECTED_EOF"
     55       ,"OUTBUFF_FULL"
     56       ,"???"   /* for future */
     57       ,"???"   /* for future */
     58       ,"???"   /* for future */
     59       ,"???"   /* for future */
     60       ,"???"   /* for future */
     61       ,"???"   /* for future */
     62 };
     63 
     64 void flip_bit ( int bit )
     65 {
     66    int byteno = bit / 8;
     67    int bitno  = bit % 8;
     68    uchar mask = 1 << bitno;
     69    //fprintf ( stderr, "(byte %d  bit %d  mask %d)",
     70    //          byteno, bitno, (int)mask );
     71    zbuf[byteno] ^= mask;
     72 }
     73 
     74 int main ( int argc, char** argv )
     75 {
     76    FILE* f;
     77    int   r;
     78    int   bit;
     79    int   i;
     80 
     81    if (argc != 2) {
     82       fprintf ( stderr, "usage: unzcrash filename\n" );
     83       return 1;
     84    }
     85 
     86    f = fopen ( argv[1], "r" );
     87    if (!f) {
     88       fprintf ( stderr, "unzcrash: can't open %s\n", argv[1] );
     89       return 1;
     90    }
     91 
     92    nIn = fread ( inbuf, 1, M_BLOCK, f );
     93    fprintf ( stderr, "%d bytes read\n", nIn );
     94 
     95    nZ = M_BLOCK;
     96    r = BZ2_bzBuffToBuffCompress (
     97          zbuf, &nZ, inbuf, nIn, 9, 0, 30 );
     98 
     99    assert (r == BZ_OK);
    100    fprintf ( stderr, "%d after compression\n", nZ );
    101 
    102    for (bit = 0; bit < nZ*8; bit++) {
    103       fprintf ( stderr, "bit %d  ", bit );
    104       flip_bit ( bit );
    105       nOut = M_BLOCK_OUT;
    106       r = BZ2_bzBuffToBuffDecompress (
    107             outbuf, &nOut, zbuf, nZ, 0, 0 );
    108       fprintf ( stderr, " %d  %s ", r, bzerrorstrings[-r] );
    109 
    110       if (r != BZ_OK) {
    111          fprintf ( stderr, "\n" );
    112       } else {
    113          if (nOut != nIn) {
    114            fprintf(stderr, "nIn/nOut mismatch %d %d\n", nIn, nOut );
    115            return 1;
    116          } else {
    117            for (i = 0; i < nOut; i++)
    118              if (inbuf[i] != outbuf[i]) {
    119                 fprintf(stderr, "mismatch at %d\n", i );
    120                 return 1;
    121            }
    122            if (i == nOut) fprintf(stderr, "really ok!\n" );
    123          }
    124       }
    125 
    126       flip_bit ( bit );
    127    }
    128 
    129 #if 0
    130    assert (nOut == nIn);
    131    for (i = 0; i < nOut; i++) {
    132      if (inbuf[i] != outbuf[i]) {
    133         fprintf ( stderr, "difference at %d !\n", i );
    134         return 1;
    135      }
    136    }
    137 #endif
    138 
    139    fprintf ( stderr, "all ok\n" );
    140    return 0;
    141 }
    142