Show unzcrash.c syntax highlighted
/* A test program written to test robustness to decompression of
corrupted data. Usage is
unzcrash filename
and the program will read the specified file, compress it (in memory),
and then repeatedly decompress it, each time with a different bit of
the compressed data inverted, so as to test all possible one-bit errors.
This should not cause any invalid memory accesses. If it does,
I want to know about it!
p.s. As you can see from the above description, the process is
incredibly slow. A file of size eg 5KB will cause it to run for
many hours.
*/
#include <stdio.h>
#include <assert.h>
#include "bzlib.h"
#define M_BLOCK 1000000
typedef unsigned char uchar;
#define M_BLOCK_OUT (M_BLOCK + 1000000)
uchar inbuf[M_BLOCK];
uchar outbuf[M_BLOCK_OUT];
uchar zbuf[M_BLOCK + 600 + (M_BLOCK / 100)];
int nIn, nOut, nZ;
static char *bzerrorstrings[] = {
"OK"
,"SEQUENCE_ERROR"
,"PARAM_ERROR"
,"MEM_ERROR"
,"DATA_ERROR"
,"DATA_ERROR_MAGIC"
,"IO_ERROR"
,"UNEXPECTED_EOF"
,"OUTBUFF_FULL"
,"???" /* for future */
,"???" /* for future */
,"???" /* for future */
,"???" /* for future */
,"???" /* for future */
,"???" /* for future */
};
void flip_bit ( int bit )
{
int byteno = bit / 8;
int bitno = bit % 8;
uchar mask = 1 << bitno;
//fprintf ( stderr, "(byte %d bit %d mask %d)",
// byteno, bitno, (int)mask );
zbuf[byteno] ^= mask;
}
int main ( int argc, char** argv )
{
FILE* f;
int r;
int bit;
int i;
if (argc != 2) {
fprintf ( stderr, "usage: unzcrash filename\n" );
return 1;
}
f = fopen ( argv[1], "r" );
if (!f) {
fprintf ( stderr, "unzcrash: can't open %s\n", argv[1] );
return 1;
}
nIn = fread ( inbuf, 1, M_BLOCK, f );
fprintf ( stderr, "%d bytes read\n", nIn );
nZ = M_BLOCK;
r = BZ2_bzBuffToBuffCompress (
zbuf, &nZ, inbuf, nIn, 9, 0, 30 );
assert (r == BZ_OK);
fprintf ( stderr, "%d after compression\n", nZ );
for (bit = 0; bit < nZ*8; bit++) {
fprintf ( stderr, "bit %d ", bit );
flip_bit ( bit );
nOut = M_BLOCK_OUT;
r = BZ2_bzBuffToBuffDecompress (
outbuf, &nOut, zbuf, nZ, 0, 0 );
fprintf ( stderr, " %d %s ", r, bzerrorstrings[-r] );
if (r != BZ_OK) {
fprintf ( stderr, "\n" );
} else {
if (nOut != nIn) {
fprintf(stderr, "nIn/nOut mismatch %d %d\n", nIn, nOut );
return 1;
} else {
for (i = 0; i < nOut; i++)
if (inbuf[i] != outbuf[i]) {
fprintf(stderr, "mismatch at %d\n", i );
return 1;
}
if (i == nOut) fprintf(stderr, "really ok!\n" );
}
}
flip_bit ( bit );
}
#if 0
assert (nOut == nIn);
for (i = 0; i < nOut; i++) {
if (inbuf[i] != outbuf[i]) {
fprintf ( stderr, "difference at %d !\n", i );
return 1;
}
}
#endif
fprintf ( stderr, "all ok\n" );
return 0;
}
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