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bzip2/bzip2recover.c

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/*-----------------------------------------------------------*/
/*--- Block recoverer program for bzip2 ---*/
/*--- bzip2recover.c ---*/
/*-----------------------------------------------------------*/
/* ------------------------------------------------------------------
This file is part of bzip2/libbzip2, a program and library for
lossless, block-sorting data compression.
bzip2/libbzip2 version 1.0.8 of 13 July 2019
Copyright (C) 1996-2019 Julian Seward <jseward@acm.org>
Please read the WARNING, DISCLAIMER and PATENTS sections in the
README file.
This program is released under the terms of the license contained
in the file LICENSE.
------------------------------------------------------------------ */
/* 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 ---*/
/*---------------------------------------------------*/
/*---------------------------------------------*/
static 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 );
}
/*---------------------------------------------*/
static 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 );
}
/*---------------------------------------------*/
static 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 );
}
/*---------------------------------------------*/
static 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;
/*---------------------------------------------*/
static 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;
}
/*---------------------------------------------*/
static 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;
}
/*---------------------------------------------*/
static 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.
--*/
static 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 );
}
}
/*---------------------------------------------*/
static 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 );
}
/*---------------------------------------------*/
static void bsPutUChar ( BitStream* bs, UChar c )
{
Int32 i;
for (i = 7; i >= 0; i--)
bsPutBit ( bs, (((UInt32) c) >> i) & 0x1 );
}
/*---------------------------------------------*/
static void bsPutUInt32 ( BitStream* bs, UInt32 c )
{
Int32 i;
for (i = 31; i >= 0; i--)
bsPutBit ( bs, (c >> i) & 0x1 );
}
/*---------------------------------------------*/
static 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;
strncpy ( progName, argv[0], BZ_MAX_FILENAME-1);
progName[BZ_MAX_FILENAME-1]='\0';
inFileName[0] = outFileName[0] = 0;
fprintf ( stderr,
"bzip2recover 1.0.8: 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, (int)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 );
outFile = NULL;
}
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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