unzcrash.c revision 78556 
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   p.s.  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#include <stdio.h>
17#include <assert.h>
18#include "bzlib.h"
19
20#define M_BLOCK 1000000
21
22typedef unsigned char uchar;
23
24#define M_BLOCK_OUT (M_BLOCK + 1000000)
25uchar inbuf[M_BLOCK];
26uchar outbuf[M_BLOCK_OUT];
27uchar zbuf[M_BLOCK + 600 + (M_BLOCK / 100)];
28
29int nIn, nOut, nZ;
30
31static char *bzerrorstrings[] = {
32       "OK"
33      ,"SEQUENCE_ERROR"
34      ,"PARAM_ERROR"
35      ,"MEM_ERROR"
36      ,"DATA_ERROR"
37      ,"DATA_ERROR_MAGIC"
38      ,"IO_ERROR"
39      ,"UNEXPECTED_EOF"
40      ,"OUTBUFF_FULL"
41      ,"???"   /* for future */
42      ,"???"   /* for future */
43      ,"???"   /* for future */
44      ,"???"   /* for future */
45      ,"???"   /* for future */
46      ,"???"   /* for future */
47};
48
49void flip_bit ( int bit )
50{
51   int byteno = bit / 8;
52   int bitno  = bit % 8;
53   uchar mask = 1 << bitno;
54   //fprintf ( stderr, "(byte %d  bit %d  mask %d)",
55   //          byteno, bitno, (int)mask );
56   zbuf[byteno] ^= mask;
57}
58
59int main ( int argc, char** argv )
60{
61   FILE* f;
62   int   r;
63   int   bit;
64   int   i;
65
66   if (argc != 2) {
67      fprintf ( stderr, "usage: unzcrash filename\n" );
68      return 1;
69   }
70
71   f = fopen ( argv[1], "r" );
72   if (!f) {
73      fprintf ( stderr, "unzcrash: can't open %s\n", argv[1] );
74      return 1;
75   }
76
77   nIn = fread ( inbuf, 1, M_BLOCK, f );
78   fprintf ( stderr, "%d bytes read\n", nIn );
79
80   nZ = M_BLOCK;
81   r = BZ2_bzBuffToBuffCompress (
82         zbuf, &nZ, inbuf, nIn, 9, 0, 30 );
83
84   assert (r == BZ_OK);
85   fprintf ( stderr, "%d after compression\n", nZ );
86
87   for (bit = 0; bit < nZ*8; bit++) {
88      fprintf ( stderr, "bit %d  ", bit );
89      flip_bit ( bit );
90      nOut = M_BLOCK_OUT;
91      r = BZ2_bzBuffToBuffDecompress (
92            outbuf, &nOut, zbuf, nZ, 0, 0 );
93      fprintf ( stderr, " %d  %s ", r, bzerrorstrings[-r] );
94
95      if (r != BZ_OK) {
96         fprintf ( stderr, "\n" );
97      } else {
98         if (nOut != nIn) {
99           fprintf(stderr, "nIn/nOut mismatch %d %d\n", nIn, nOut );
100           return 1;
101         } else {
102           for (i = 0; i < nOut; i++)
103             if (inbuf[i] != outbuf[i]) {
104                fprintf(stderr, "mismatch at %d\n", i );
105                return 1;
106           }
107           if (i == nOut) fprintf(stderr, "really ok!\n" );
108         }
109      }
110
111      flip_bit ( bit );
112   }
113
114#if 0
115   assert (nOut == nIn);
116   for (i = 0; i < nOut; i++) {
117     if (inbuf[i] != outbuf[i]) {
118        fprintf ( stderr, "difference at %d !\n", i );
119        return 1;
120     }
121   }
122#endif
123
124   fprintf ( stderr, "all ok\n" );
125   return 0;
126}
127