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bunzip2/bzip2recover.c

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/*-----------------------------------------------------------*/
/*--- 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) 1996-2002 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>
/* This program records bit locations in the file to be recovered.
That means that if 64-bit ints are not supported, we will not
be able to recover .bz2 files over 512MB (2^32 bits) long.
On GNU supported platforms, we take advantage of the 64-bit
int support to circumvent this problem. Ditto MSVC.
This change occurred in version 1.0.2; all prior versions have
the 512MB limitation.
*/
#ifdef __GNUC__
typedef unsigned long long int MaybeUInt64;
# define MaybeUInt64_FMT "%Lu"
#else
#ifdef _MSC_VER
typedef unsigned __int64 MaybeUInt64;
# define MaybeUInt64_FMT "%I64u"
#else
typedef unsigned int MaybeUInt64;
# define MaybeUInt64_FMT "%u"
#endif
#endif
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)
#define BZ_MAX_FILENAME 2000
Char inFileName[BZ_MAX_FILENAME];
Char outFileName[BZ_MAX_FILENAME];
Char progName[BZ_MAX_FILENAME];
MaybeUInt64 bytesOut = 0;
MaybeUInt64 bytesIn = 0;
/*---------------------------------------------------*/
/*--- Header bytes ---*/
/*---------------------------------------------------*/
#define BZ_HDR_B 0x42 /* 'B' */
#define BZ_HDR_Z 0x5a /* 'Z' */
#define BZ_HDR_h 0x68 /* 'h' */
#define BZ_HDR_0 0x30 /* '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 );
}
/*---------------------------------------------*/
void tooManyBlocks ( Int32 max_handled_blocks )
{
fprintf ( stderr,
"%s: `%s' appears to contain more than %d blocks\n",
progName, inFileName, max_handled_blocks );
fprintf ( stderr,
"%s: and cannot be handled. To fix, increase\n",
progName );
fprintf ( stderr,
"%s: BZ_MAX_HANDLED_BLOCKS in bzip2recover.c, and recompile.\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');
}
/*---------------------------------------------------*/
/*--- ---*/
/*---------------------------------------------------*/
/* This logic isn't really right when it comes to Cygwin. */
#ifdef _WIN32
# define BZ_SPLIT_SYM '\\' /* path splitter on Windows platform */
#else
# define BZ_SPLIT_SYM '/' /* path splitter on Unix platform */
#endif
#define BLOCK_HEADER_HI 0x00003141UL
#define BLOCK_HEADER_LO 0x59265359UL
#define BLOCK_ENDMARK_HI 0x00001772UL
#define BLOCK_ENDMARK_LO 0x45385090UL
/* Increase if necessary. However, a .bz2 file with > 50000 blocks
would have an uncompressed size of at least 40GB, so the chances
are low you'll need to up this.
*/
#define BZ_MAX_HANDLED_BLOCKS 50000
MaybeUInt64 bStart [BZ_MAX_HANDLED_BLOCKS];
MaybeUInt64 bEnd [BZ_MAX_HANDLED_BLOCKS];
MaybeUInt64 rbStart[BZ_MAX_HANDLED_BLOCKS];
MaybeUInt64 rbEnd [BZ_MAX_HANDLED_BLOCKS];
Int32 main ( Int32 argc, Char** argv )
{
FILE* inFile;
FILE* outFile;
BitStream* bsIn, *bsWr;
Int32 b, wrBlock, currBlock, rbCtr;
MaybeUInt64 bitsRead;
UInt32 buffHi, buffLo, blockCRC;
Char* p;
strcpy ( progName, argv[0] );
inFileName[0] = outFileName[0] = 0;
fprintf ( stderr,
"bzip2recover 1.0.2: extracts blocks from damaged .bz2 files.\n" );
if (argc != 2) {
fprintf ( stderr, "%s: usage is `%s damaged_file_name'.\n",
progName, progName );
switch (sizeof(MaybeUInt64)) {
case 8:
fprintf(stderr,
"\trestrictions on size of recovered file: None\n");
break;
case 4:
fprintf(stderr,
"\trestrictions on size of recovered file: 512 MB\n");
fprintf(stderr,
"\tto circumvent, recompile with MaybeUInt64 as an\n"
"\tunsigned 64-bit int.\n");
break;
default:
fprintf(stderr,
"\tsizeof(MaybeUInt64) is not 4 or 8 -- "
"configuration error.\n");
break;
}
exit(1);
}
if (strlen(argv[1]) >= BZ_MAX_FILENAME-20) {
fprintf ( stderr,
"%s: supplied filename is suspiciously (>= %d chars) long. Bye!\n",
progName, strlen(argv[1]) );
exit(1);
}
strcpy ( 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 " MaybeUInt64_FMT
" to " MaybeUInt64_FMT " (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 " MaybeUInt64_FMT
" to " MaybeUInt64_FMT "\n",
rbCtr+1, bStart[currBlock], bEnd[currBlock] );
rbStart[rbCtr] = bStart[currBlock];
rbEnd[rbCtr] = bEnd[currBlock];
rbCtr++;
}
if (currBlock >= BZ_MAX_HANDLED_BLOCKS)
tooManyBlocks(BZ_MAX_HANDLED_BLOCKS);
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]) {
/* Create the output file name, correctly handling leading paths.
(31.10.2001 by Sergey E. Kusikov) */
Char* split;
Int32 ofs, k;
for (k = 0; k < BZ_MAX_FILENAME; k++)
outFileName[k] = 0;
strcpy (outFileName, inFileName);
split = strrchr (outFileName, BZ_SPLIT_SYM);
if (split == NULL) {
split = outFileName;
} else {
++split;
}
/* Now split points to the start of the basename. */
ofs = split - outFileName;
sprintf (split, "rec%5d", wrBlock+1);
for (p = split; *p != 0; p++) if (*p == ' ') *p = '0';
strcat (outFileName, inFileName + ofs);
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, BZ_HDR_B );
bsPutUChar ( bsWr, BZ_HDR_Z );
bsPutUChar ( bsWr, BZ_HDR_h );
bsPutUChar ( bsWr, BZ_HDR_0 + 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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