/*-----------------------------------------------------------*/
/*--- Block recoverer program for bzip2 ---*/
/*--- bzip2recover.c ---*/
/*-----------------------------------------------------------*/
/*--
This program is bzip2recover, a program to attempt data
salvage from damaged files created by the accompanying
bzip2-1.0 program.
Copyright (C) 1996-2000 Julian R Seward. All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
2. The origin of this software must not be misrepresented; you must
not claim that you wrote the original software. If you use this
software in a product, an acknowledgment in the product
documentation would be appreciated but is not required.
3. Altered source versions must be plainly marked as such, and must
not be misrepresented as being the original software.
4. The name of the author may not be used to endorse or promote
products derived from this software without specific prior written
permission.
THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
Julian Seward, Cambridge, UK.
jseward@acm.org
bzip2/libbzip2 version 1.0 of 21 March 2000
--*/
/*--
This program is a complete hack and should be rewritten
properly. It isn't very complicated.
--*/
#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
typedef unsigned int UInt32;
typedef int Int32;
typedef unsigned char UChar;
typedef char Char;
typedef unsigned char Bool;
#define True ((Bool)1)
#define False ((Bool)0)
Char inFileName[2000];
Char outFileName[2000];
Char progName[2000];
UInt32 bytesOut = 0;
UInt32 bytesIn = 0;
/*---------------------------------------------------*/
/*--- I/O errors ---*/
/*---------------------------------------------------*/
/*---------------------------------------------*/
void readError ( void )
{
fprintf ( stderr,
"%s: I/O error reading `%s', possible reason follows.\n",
progName, inFileName );
perror ( progName );
fprintf ( stderr, "%s: warning: output file(s) may be incomplete.\n",
progName );
exit ( 1 );
}
/*---------------------------------------------*/
void writeError ( void )
{
fprintf ( stderr,
"%s: I/O error reading `%s', possible reason follows.\n",
progName, inFileName );
perror ( progName );
fprintf ( stderr, "%s: warning: output file(s) may be incomplete.\n",
progName );
exit ( 1 );
}
/*---------------------------------------------*/
void mallocFail ( Int32 n )
{
fprintf ( stderr,
"%s: malloc failed on request for %d bytes.\n",
progName, n );
fprintf ( stderr, "%s: warning: output file(s) may be incomplete.\n",
progName );
exit ( 1 );
}
/*---------------------------------------------------*/
/*--- Bit stream I/O ---*/
/*---------------------------------------------------*/
typedef
struct {
FILE* handle;
Int32 buffer;
Int32 buffLive;
Char mode;
}
BitStream;
/*---------------------------------------------*/
BitStream* bsOpenReadStream ( FILE* stream )
{
BitStream *bs = malloc ( sizeof(BitStream) );
if (bs == NULL) mallocFail ( sizeof(BitStream) );
bs->handle = stream;
bs->buffer = 0;
bs->buffLive = 0;
bs->mode = 'r';
return bs;
}
/*---------------------------------------------*/
BitStream* bsOpenWriteStream ( FILE* stream )
{
BitStream *bs = malloc ( sizeof(BitStream) );
if (bs == NULL) mallocFail ( sizeof(BitStream) );
bs->handle = stream;
bs->buffer = 0;
bs->buffLive = 0;
bs->mode = 'w';
return bs;
}
/*---------------------------------------------*/
void bsPutBit ( BitStream* bs, Int32 bit )
{
if (bs->buffLive == 8) {
Int32 retVal = putc ( (UChar) bs->buffer, bs->handle );
if (retVal == EOF) writeError();
bytesOut++;
bs->buffLive = 1;
bs->buffer = bit & 0x1;
} else {
bs->buffer = ( (bs->buffer << 1) | (bit & 0x1) );
bs->buffLive++;
};
}
/*---------------------------------------------*/
/*--
Returns 0 or 1, or 2 to indicate EOF.
--*/
Int32 bsGetBit ( BitStream* bs )
{
if (bs->buffLive > 0) {
bs->buffLive --;
return ( ((bs->buffer) >> (bs->buffLive)) & 0x1 );
} else {
Int32 retVal = getc ( bs->handle );
if ( retVal == EOF ) {
if (errno != 0) readError();
return 2;
}
bs->buffLive = 7;
bs->buffer = retVal;
return ( ((bs->buffer) >> 7) & 0x1 );
}
}
/*---------------------------------------------*/
void bsClose ( BitStream* bs )
{
Int32 retVal;
if ( bs->mode == 'w' ) {
while ( bs->buffLive < 8 ) {
bs->buffLive++;
bs->buffer <<= 1;
};
retVal = putc ( (UChar) (bs->buffer), bs->handle );
if (retVal == EOF) writeError();
bytesOut++;
retVal = fflush ( bs->handle );
if (retVal == EOF) writeError();
}
retVal = fclose ( bs->handle );
if (retVal == EOF) {
if (bs->mode == 'w') writeError(); else readError();
}
free ( bs );
}
/*---------------------------------------------*/
void bsPutUChar ( BitStream* bs, UChar c )
{
Int32 i;
for (i = 7; i >= 0; i--)
bsPutBit ( bs, (((UInt32) c) >> i) & 0x1 );
}
/*---------------------------------------------*/
void bsPutUInt32 ( BitStream* bs, UInt32 c )
{
Int32 i;
for (i = 31; i >= 0; i--)
bsPutBit ( bs, (c >> i) & 0x1 );
}
/*---------------------------------------------*/
Bool endsInBz2 ( Char* name )
{
Int32 n = strlen ( name );
if (n <= 4) return False;
return
(name[n-4] == '.' &&
name[n-3] == 'b' &&
name[n-2] == 'z' &&
name[n-1] == '2');
}
/*---------------------------------------------------*/
/*--- ---*/
/*---------------------------------------------------*/
#define BLOCK_HEADER_HI 0x00003141UL
#define BLOCK_HEADER_LO 0x59265359UL
#define BLOCK_ENDMARK_HI 0x00001772UL
#define BLOCK_ENDMARK_LO 0x45385090UL
UInt32 bStart[20000];
UInt32 bEnd[20000];
UInt32 rbStart[20000];
UInt32 rbEnd[20000];
Int32 main ( Int32 argc, Char** argv )
{
FILE* inFile;
FILE* outFile;
BitStream* bsIn, *bsWr;
Int32 currBlock, b, wrBlock;
UInt32 bitsRead;
Int32 rbCtr;
UInt32 buffHi, buffLo, blockCRC;
Char* p;
strcpy ( progName, argv[0] );
inFileName[0] = outFileName[0] = 0;
fprintf ( stderr, "bzip2recover 1.0: extracts blocks from damaged .bz2 files.\n" );
if (argc != 2) {
fprintf ( stderr, "%s: usage is `%s damaged_file_name'.\n",
progName, progName );
exit(1);
}
strecpy ( inFileName, inFileName + sizeof(inFileName), argv[1] );
inFile = fopen ( inFileName, "rb" );
if (inFile == NULL) {
fprintf ( stderr, "%s: can't read `%s'\n", progName, inFileName );
exit(1);
}
bsIn = bsOpenReadStream ( inFile );
fprintf ( stderr, "%s: searching for block boundaries ...\n", progName );
bitsRead = 0;
buffHi = buffLo = 0;
currBlock = 0;
bStart[currBlock] = 0;
rbCtr = 0;
while (True) {
b = bsGetBit ( bsIn );
bitsRead++;
if (b == 2) {
if (bitsRead >= bStart[currBlock] &&
(bitsRead - bStart[currBlock]) >= 40) {
bEnd[currBlock] = bitsRead-1;
if (currBlock > 0)
fprintf ( stderr, " block %d runs from %d to %d (incomplete)\n",
currBlock, bStart[currBlock], bEnd[currBlock] );
} else
currBlock--;
break;
}
buffHi = (buffHi << 1) | (buffLo >> 31);
buffLo = (buffLo << 1) | (b & 1);
if ( ( (buffHi & 0x0000ffff) == BLOCK_HEADER_HI
&& buffLo == BLOCK_HEADER_LO)
||
( (buffHi & 0x0000ffff) == BLOCK_ENDMARK_HI
&& buffLo == BLOCK_ENDMARK_LO)
) {
if (bitsRead > 49)
bEnd[currBlock] = bitsRead-49; else
bEnd[currBlock] = 0;
if (currBlock > 0 &&
(bEnd[currBlock] - bStart[currBlock]) >= 130) {
fprintf ( stderr, " block %d runs from %d to %d\n",
rbCtr+1, bStart[currBlock], bEnd[currBlock] );
rbStart[rbCtr] = bStart[currBlock];
rbEnd[rbCtr] = bEnd[currBlock];
rbCtr++;
}
currBlock++;
bStart[currBlock] = bitsRead;
}
}
bsClose ( bsIn );
/*-- identified blocks run from 1 to rbCtr inclusive. --*/
if (rbCtr < 1) {
fprintf ( stderr,
"%s: sorry, I couldn't find any block boundaries.\n",
progName );
exit(1);
};
fprintf ( stderr, "%s: splitting into blocks\n", progName );
inFile = fopen ( inFileName, "rb" );
if (inFile == NULL) {
fprintf ( stderr, "%s: can't open `%s'\n", progName, inFileName );
exit(1);
}
bsIn = bsOpenReadStream ( inFile );
/*-- placate gcc's dataflow analyser --*/
blockCRC = 0; bsWr = 0;
bitsRead = 0;
outFile = NULL;
wrBlock = 0;
while (True) {
b = bsGetBit(bsIn);
if (b == 2) break;
buffHi = (buffHi << 1) | (buffLo >> 31);
buffLo = (buffLo << 1) | (b & 1);
if (bitsRead == 47+rbStart[wrBlock])
blockCRC = (buffHi << 16) | (buffLo >> 16);
if (outFile != NULL && bitsRead >= rbStart[wrBlock]
&& bitsRead <= rbEnd[wrBlock]) {
bsPutBit ( bsWr, b );
}
bitsRead++;
if (bitsRead == rbEnd[wrBlock]+1) {
if (outFile != NULL) {
bsPutUChar ( bsWr, 0x17 ); bsPutUChar ( bsWr, 0x72 );
bsPutUChar ( bsWr, 0x45 ); bsPutUChar ( bsWr, 0x38 );
bsPutUChar ( bsWr, 0x50 ); bsPutUChar ( bsWr, 0x90 );
bsPutUInt32 ( bsWr, blockCRC );
bsClose ( bsWr );
}
if (wrBlock >= rbCtr) break;
wrBlock++;
} else
if (bitsRead == rbStart[wrBlock]) {
outFileName[0] = 0;
sprintf ( outFileName, "rec%4d", wrBlock+1 );
for (p = outFileName; *p != 0; p++) if (*p == ' ') *p = '0';
strcat ( outFileName, inFileName );
if ( !endsInBz2(outFileName)) strcat ( outFileName, ".bz2" );
fprintf ( stderr, " writing block %d to `%s' ...\n",
wrBlock+1, outFileName );
outFile = fopen ( outFileName, "wb" );
if (outFile == NULL) {
fprintf ( stderr, "%s: can't write `%s'\n",
progName, outFileName );
exit(1);
}
bsWr = bsOpenWriteStream ( outFile );
bsPutUChar ( bsWr, 'B' ); bsPutUChar ( bsWr, 'Z' );
bsPutUChar ( bsWr, 'h' ); bsPutUChar ( bsWr, '9' );
bsPutUChar ( bsWr, 0x31 ); bsPutUChar ( bsWr, 0x41 );
bsPutUChar ( bsWr, 0x59 ); bsPutUChar ( bsWr, 0x26 );
bsPutUChar ( bsWr, 0x53 ); bsPutUChar ( bsWr, 0x59 );
}
}
fprintf ( stderr, "%s: finished\n", progName );
return 0;
}
/*-----------------------------------------------------------*/
/*--- end bzip2recover.c ---*/
/*-----------------------------------------------------------*/
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