The-Homebrew-Cloud/usbloadergx
2
0
Fork 0
mirror of https://github.com/wiidev/usbloadergx.git synced 2024-09-30 10:58:38 +02:00
Code Issues Packages Projects Releases Wiki Activity
2547b9a2a5
usbloadergx/source/libntfs/compress.c
giantpune 9e79c9d99b * remove little unused code 
* code cleanup
2010-09-18 23:16:05 +00:00

2028 lines
66 KiB
C
Raw Blame History

/**
* compress.c - Compressed attribute handling code. Originated from the Linux-NTFS
* project.
*
* Copyright (c) 2004-2005 Anton Altaparmakov
* Copyright (c) 2004-2006 Szabolcs Szakacsits
* Copyright (c) 2005 Yura Pakhuchiy
* Copyright (c) 2009-2010 Jean-Pierre Andre
*
* This program/include file is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as published
* by the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program/include file is distributed in the hope that it will be
* useful, but WITHOUT ANY WARRANTY; without even the implied warranty
* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program (in the main directory of the NTFS-3G
* distribution in the file COPYING); if not, write to the Free Software
* Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* A part of the compression algorithm is based on lzhuf.c whose header
* describes the roles of the original authors (with no apparent copyright
* notice, and according to http://home.earthlink.net/~neilbawd/pall.html
* this was put into public domain in 1988 by Haruhiko OKUMURA).
*
* LZHUF.C English version 1.0
* Based on Japanese version 29-NOV-1988
* LZSS coded by Haruhiko OKUMURA
* Adaptive Huffman Coding coded by Haruyasu YOSHIZAKI
* Edited and translated to English by Kenji RIKITAKE
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#ifdef HAVE_STDIO_H
#include <stdio.h>
#endif
#ifdef HAVE_STRING_H
#include <string.h>
#endif
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif
#include "attrib.h"
#include "debug.h"
#include "volume.h"
#include "types.h"
#include "layout.h"
#include "runlist.h"
#include "compress.h"
#include "lcnalloc.h"
#include "logging.h"
#include "misc.h"
/**
* enum ntfs_compression_constants - constants used in the compression code
*/
typedef enum
{
/* Token types and access mask. */
NTFS_SYMBOL_TOKEN = 0,
NTFS_PHRASE_TOKEN = 1,
NTFS_TOKEN_MASK = 1,
/* Compression sub-block constants. */
NTFS_SB_SIZE_MASK = 0x0fff,
NTFS_SB_SIZE = 0x1000,
NTFS_SB_IS_COMPRESSED = 0x8000,
} ntfs_compression_constants;
#define THRESHOLD 3 /* minimal match length for compression */
#define NIL NTFS_SB_SIZE /* End of tree's node */
struct COMPRESS_CONTEXT
{
const unsigned char *inbuf;
unsigned int len;
unsigned int nbt;
int match_position;
unsigned int match_length;
u16 lson[NTFS_SB_SIZE + 1];
u16 rson[NTFS_SB_SIZE + 257];
u16 dad[NTFS_SB_SIZE + 1];
} ;
/*
* Initialize the match tree
*/
static void ntfs_init_compress_tree( struct COMPRESS_CONTEXT *pctx )
{
int i;
for ( i = NTFS_SB_SIZE + 1; i <= NTFS_SB_SIZE + 256; i++ )
pctx->rson[i] = NIL; /* root */
for ( i = 0; i < NTFS_SB_SIZE; i++ )
pctx->dad[i] = NIL; /* node */
}
/*
* Insert a new node into match tree for quickly locating
* further similar strings
*/
static void ntfs_new_node ( struct COMPRESS_CONTEXT *pctx,
unsigned int r )
{
unsigned int pp;
BOOL less;
BOOL done;
const unsigned char *key;
int c;
unsigned long mxi;
unsigned int mxl;
mxl = ( 1 << ( 16 - pctx->nbt ) ) + 2;
less = FALSE;
done = FALSE;
key = &pctx->inbuf[r];
pp = NTFS_SB_SIZE + 1 + key[0];
pctx->rson[r] = pctx->lson[r] = NIL;
pctx->match_length = 0;
do
{
if ( !less )
{
if ( pctx->rson[pp] != NIL )
pp = pctx->rson[pp];
else
{
pctx->rson[pp] = r;
pctx->dad[r] = pp;
done = TRUE;
}
}
else
{
if ( pctx->lson[pp] != NIL )
pp = pctx->lson[pp];
else
{
pctx->lson[pp] = r;
pctx->dad[r] = pp;
done = TRUE;
}
}
if ( !done )
{
register unsigned long i;
register const unsigned char *p1, *p2;
i = 1;
mxi = NTFS_SB_SIZE - r;
if ( mxi < 2 )
less = FALSE;
else
{
p1 = key;
p2 = &pctx->inbuf[pp];
/* this loop has a significant impact on performances */
do
{
}
while ( ( p1[i] == p2[i] ) && ( ++i < mxi ) );
less = ( i < mxi ) && ( p1[i] < p2[i] );
}
if ( i >= THRESHOLD )
{
if ( i > pctx->match_length )
{
pctx->match_position =
r - pp + 2 * NTFS_SB_SIZE - 1;
if ( ( pctx->match_length = i ) > mxl )
{
i = pctx->rson[pp];
pctx->rson[r] = i;
pctx->dad[i] = r;
i = pctx->lson[pp];
pctx->lson[r] = i;
pctx->dad[i] = r;
i = pctx->dad[pp];
pctx->dad[r] = i;
if ( pctx->rson[i] == pp )
pctx->rson[i] = r;
else
pctx->lson[i] = r;
/* remove pp */
pctx->dad[pp] = NIL;
done = TRUE;
pctx->match_length = mxl;
}
}
else if ( ( i == pctx->match_length )
&& ( ( c = ( r - pp + 2 * NTFS_SB_SIZE - 1 ) )
< pctx->match_position ) )
pctx->match_position = c;
}
}
}
while ( !done );
}
/*
* Search for the longest previous string matching the
* current one
*
* Returns the end of the longest current string which matched
* or zero if there was a bug
*/
static unsigned int ntfs_nextmatch( struct COMPRESS_CONTEXT *pctx,
unsigned int rr, int dd )
{
unsigned int bestlen = 0;
do
{
rr++;
if ( pctx->match_length > 0 )
pctx->match_length--;
if ( !pctx->len )
{
ntfs_log_error( "compress bug : void run\n" );
goto bug;
}
if ( --pctx->len )
{
if ( rr >= NTFS_SB_SIZE )
{
ntfs_log_error( "compress bug : buffer overflow\n" );
goto bug;
}
if ( ( ( rr + bestlen ) < NTFS_SB_SIZE ) )
{
while ( ( unsigned int )( 1 << pctx->nbt )
<= ( rr - 1 ) )
pctx->nbt++;
ntfs_new_node( pctx, rr );
if ( pctx->match_length > bestlen )
bestlen = pctx->match_length;
}
else if ( dd > 0 )
{
rr += dd;
if ( ( int )pctx->match_length > dd )
pctx->match_length -= dd;
else
pctx->match_length = 0;
if ( ( int )pctx->len < dd )
{
ntfs_log_error( "compress bug : run overflows\n" );
goto bug;
}
pctx->len -= dd;
dd = 0;
}
}
}
while ( dd-- > 0 );
return ( rr );
bug :
return ( 0 );
}
/*
* Compress an input block
*
* Returns the size of the compressed block (including header)
* or zero if there was an error
*/
static unsigned int ntfs_compress_block( const char *inbuf,
unsigned int size, char *outbuf )
{
struct COMPRESS_CONTEXT *pctx;
char *ptag;
int dd;
unsigned int rr;
unsigned int last_match_length;
unsigned int q;
unsigned int xout;
unsigned int ntag;
pctx = ( struct COMPRESS_CONTEXT* )malloc( sizeof( struct COMPRESS_CONTEXT ) );
if ( pctx )
{
pctx->inbuf = ( const unsigned char* )inbuf;
ntfs_init_compress_tree( pctx );
xout = 2;
ntag = 0;
ptag = &outbuf[xout++];
*ptag = 0;
rr = 0;
pctx->nbt = 4;
pctx->len = size;
pctx->match_length = 0;
ntfs_new_node( pctx, 0 );
do
{
if ( pctx->match_length > pctx->len )
pctx->match_length = pctx->len;
if ( pctx->match_length < THRESHOLD )
{
pctx->match_length = 1;
if ( ntag >= 8 )
{
ntag = 0;
ptag = &outbuf[xout++];
*ptag = 0;
}
outbuf[xout++] = inbuf[rr];
ntag++;
}
else
{
while ( ( unsigned int )( 1 << pctx->nbt )
<= ( rr - 1 ) )
pctx->nbt++;
q = ( pctx->match_position << ( 16 - pctx->nbt ) )
+ pctx->match_length - THRESHOLD;
if ( ntag >= 8 )
{
ntag = 0;
ptag = &outbuf[xout++];
*ptag = 0;
}
*ptag |= 1 << ntag++;
outbuf[xout++] = q & 255;
outbuf[xout++] = ( q >> 8 ) & 255;
}
last_match_length = pctx->match_length;
dd = last_match_length;
if ( dd-- > 0 )
{
rr = ntfs_nextmatch( pctx, rr, dd );
if ( !rr )
goto bug;
}
/*
* stop if input is exhausted or output has exceeded
* the maximum size. Two extra bytes have to be
* reserved in output buffer, as 3 bytes may be
* output in a loop.
*/
}
while ( ( pctx->len > 0 )
&& ( rr < size ) && ( xout < ( NTFS_SB_SIZE + 2 ) ) );
/* uncompressed must be full size, so accept if better */
if ( xout < ( NTFS_SB_SIZE + 2 ) )
{
outbuf[0] = ( xout - 3 ) & 255;
outbuf[1] = 0xb0 + ( ( ( xout - 3 ) >> 8 ) & 15 );
}
else
{
memcpy( &outbuf[2], inbuf, size );
if ( size < NTFS_SB_SIZE )
memset( &outbuf[size+2], 0, NTFS_SB_SIZE - size );
outbuf[0] = 0xff;
outbuf[1] = 0x3f;
xout = NTFS_SB_SIZE + 2;
}
free( pctx );
}
else
{
xout = 0;
errno = ENOMEM;
}
return ( xout ); /* 0 for an error, > size if cannot compress */
bug :
return ( 0 );
}
/**
* ntfs_decompress - decompress a compression block into an array of pages
* @dest: buffer to which to write the decompressed data
* @dest_size: size of buffer @dest in bytes
* @cb_start: compression block to decompress
* @cb_size: size of compression block @cb_start in bytes
*
* This decompresses the compression block @cb_start into the destination
* buffer @dest.
*
* @cb_start is a pointer to the compression block which needs decompressing
* and @cb_size is the size of @cb_start in bytes (8-64kiB).
*
* Return 0 if success or -EOVERFLOW on error in the compressed stream.
*/
static int ntfs_decompress( u8 *dest, const u32 dest_size,
u8 *const cb_start, const u32 cb_size )
{
/*
* Pointers into the compressed data, i.e. the compression block (cb),
* and the therein contained sub-blocks (sb).
*/
u8 *cb_end = cb_start + cb_size; /* End of cb. */
u8 *cb = cb_start; /* Current position in cb. */
u8 *cb_sb_start = cb; /* Beginning of the current sb in the cb. */
u8 *cb_sb_end; /* End of current sb / beginning of next sb. */
/* Variables for uncompressed data / destination. */
u8 *dest_end = dest + dest_size; /* End of dest buffer. */
u8 *dest_sb_start; /* Start of current sub-block in dest. */
u8 *dest_sb_end; /* End of current sb in dest. */
/* Variables for tag and token parsing. */
u8 tag; /* Current tag. */
int token; /* Loop counter for the eight tokens in tag. */
ntfs_log_trace( "Entering, cb_size = 0x%x.\n", ( unsigned )cb_size );
do_next_sb:
ntfs_log_debug( "Beginning sub-block at offset = %d in the cb.\n",
( int )( cb - cb_start ) );
/*
* Have we reached the end of the compression block or the end of the
* decompressed data? The latter can happen for example if the current
* position in the compression block is one byte before its end so the
* first two checks do not detect it.
*/
if ( cb == cb_end || !le16_to_cpup( ( le16* )cb ) || dest == dest_end )
{
ntfs_log_debug( "Completed. Returning success (0).\n" );
return 0;
}
/* Setup offset for the current sub-block destination. */
dest_sb_start = dest;
dest_sb_end = dest + NTFS_SB_SIZE;
/* Check that we are still within allowed boundaries. */
if ( dest_sb_end > dest_end )
goto return_overflow;
/* Does the minimum size of a compressed sb overflow valid range? */
if ( cb + 6 > cb_end )
goto return_overflow;
/* Setup the current sub-block source pointers and validate range. */
cb_sb_start = cb;
cb_sb_end = cb_sb_start + ( le16_to_cpup( ( le16* )cb ) & NTFS_SB_SIZE_MASK )
+ 3;
if ( cb_sb_end > cb_end )
goto return_overflow;
/* Now, we are ready to process the current sub-block (sb). */
if ( !( le16_to_cpup( ( le16* )cb ) & NTFS_SB_IS_COMPRESSED ) )
{
ntfs_log_debug( "Found uncompressed sub-block.\n" );
/* This sb is not compressed, just copy it into destination. */
/* Advance source position to first data byte. */
cb += 2;
/* An uncompressed sb must be full size. */
if ( cb_sb_end - cb != NTFS_SB_SIZE )
goto return_overflow;
/* Copy the block and advance the source position. */
memcpy( dest, cb, NTFS_SB_SIZE );
cb += NTFS_SB_SIZE;
/* Advance destination position to next sub-block. */
dest += NTFS_SB_SIZE;
goto do_next_sb;
}
ntfs_log_debug( "Found compressed sub-block.\n" );
/* This sb is compressed, decompress it into destination. */
/* Forward to the first tag in the sub-block. */
cb += 2;
do_next_tag:
if ( cb == cb_sb_end )
{
/* Check if the decompressed sub-block was not full-length. */
if ( dest < dest_sb_end )
{
int nr_bytes = dest_sb_end - dest;
ntfs_log_debug( "Filling incomplete sub-block with zeroes.\n" );
/* Zero remainder and update destination position. */
memset( dest, 0, nr_bytes );
dest += nr_bytes;
}
/* We have finished the current sub-block. */
goto do_next_sb;
}
/* Check we are still in range. */
if ( cb > cb_sb_end || dest > dest_sb_end )
goto return_overflow;
/* Get the next tag and advance to first token. */
tag = *cb++;
/* Parse the eight tokens described by the tag. */
for ( token = 0; token < 8; token++, tag >>= 1 )
{
u16 lg, pt, length, max_non_overlap;
register u16 i;
u8 *dest_back_addr;
/* Check if we are done / still in range. */
if ( cb >= cb_sb_end || dest > dest_sb_end )
break;
/* Determine token type and parse appropriately.*/
if ( ( tag & NTFS_TOKEN_MASK ) == NTFS_SYMBOL_TOKEN )
{
/*
* We have a symbol token, copy the symbol across, and
* advance the source and destination positions.
*/
*dest++ = *cb++;
/* Continue with the next token. */
continue;
}
/*
* We have a phrase token. Make sure it is not the first tag in
* the sb as this is illegal and would confuse the code below.
*/
if ( dest == dest_sb_start )
goto return_overflow;
/*
* Determine the number of bytes to go back (p) and the number
* of bytes to copy (l). We use an optimized algorithm in which
* we first calculate log2(current destination position in sb),
* which allows determination of l and p in O(1) rather than
* O(n). We just need an arch-optimized log2() function now.
*/
lg = 0;
for ( i = dest - dest_sb_start - 1; i >= 0x10; i >>= 1 )
lg++;
/* Get the phrase token into i. */
pt = le16_to_cpup( ( le16* )cb );
/*
* Calculate starting position of the byte sequence in
* the destination using the fact that p = (pt >> (12 - lg)) + 1
* and make sure we don't go too far back.
*/
dest_back_addr = dest - ( pt >> ( 12 - lg ) ) - 1;
if ( dest_back_addr < dest_sb_start )
goto return_overflow;
/* Now calculate the length of the byte sequence. */
length = ( pt & ( 0xfff >> lg ) ) + 3;
/* Verify destination is in range. */
if ( dest + length > dest_sb_end )
goto return_overflow;
/* The number of non-overlapping bytes. */
max_non_overlap = dest - dest_back_addr;
if ( length <= max_non_overlap )
{
/* The byte sequence doesn't overlap, just copy it. */
memcpy( dest, dest_back_addr, length );
/* Advance destination pointer. */
dest += length;
}
else
{
/*
* The byte sequence does overlap, copy non-overlapping
* part and then do a slow byte by byte copy for the
* overlapping part. Also, advance the destination
* pointer.
*/
memcpy( dest, dest_back_addr, max_non_overlap );
dest += max_non_overlap;
dest_back_addr += max_non_overlap;
length -= max_non_overlap;
while ( length-- )
*dest++ = *dest_back_addr++;
}
/* Advance source position and continue with the next token. */
cb += 2;
}
/* No tokens left in the current tag. Continue with the next tag. */
goto do_next_tag;
return_overflow:
errno = EOVERFLOW;
ntfs_log_perror( "Failed to decompress file" );
return -1;
}
/**
* ntfs_is_cb_compressed - internal function, do not use
*
* This is a very specialised function determining if a cb is compressed or
* uncompressed. It is assumed that checking for a sparse cb has already been
* performed and that the cb is not sparse. It makes all sorts of other
* assumptions as well and hence it is not useful anywhere other than where it
* is used at the moment. Please, do not make this function available for use
* outside of compress.c as it is bound to confuse people and not do what they
* want.
*
* Return TRUE on errors so that the error will be detected later on in the
* code. Might be a bit confusing to debug but there really should never be
* errors coming from here.
*/
static BOOL ntfs_is_cb_compressed( ntfs_attr *na, runlist_element *rl,
VCN cb_start_vcn, int cb_clusters )
{
/*
* The simplest case: the run starting at @cb_start_vcn contains
* @cb_clusters clusters which are all not sparse, thus the cb is not
* compressed.
*/
restart:
cb_clusters -= rl->length - ( cb_start_vcn - rl->vcn );
while ( cb_clusters > 0 )
{
/* Go to the next run. */
rl++;
/* Map the next runlist fragment if it is not mapped. */
if ( rl->lcn < LCN_HOLE || !rl->length )
{
cb_start_vcn = rl->vcn;
rl = ntfs_attr_find_vcn( na, rl->vcn );
if ( !rl || rl->lcn < LCN_HOLE || !rl->length )
return TRUE;
/*
* If the runs were merged need to deal with the
* resulting partial run so simply restart.
*/
if ( rl->vcn < cb_start_vcn )
goto restart;
}
/* If the current run is sparse, the cb is compressed. */
if ( rl->lcn == LCN_HOLE )
return TRUE;
/* If the whole cb is not sparse, it is not compressed. */
if ( rl->length >= cb_clusters )
return FALSE;
cb_clusters -= rl->length;
};
/* All cb_clusters were not sparse thus the cb is not compressed. */
return FALSE;
}
/**
* ntfs_compressed_attr_pread - read from a compressed attribute
* @na: ntfs attribute to read from
* @pos: byte position in the attribute to begin reading from
* @count: number of bytes to read
* @b: output data buffer
*
* NOTE: You probably want to be using attrib.c::ntfs_attr_pread() instead.
*
* This function will read @count bytes starting at offset @pos from the
* compressed ntfs attribute @na into the data buffer @b.
*
* On success, return the number of successfully read bytes. If this number
* is lower than @count this means that the read reached end of file or that
* an error was encountered during the read so that the read is partial.
* 0 means end of file or nothing was read (also return 0 when @count is 0).
*
* On error and nothing has been read, return -1 with errno set appropriately
* to the return code of ntfs_pread(), or to EINVAL in case of invalid
* arguments.
*/
s64 ntfs_compressed_attr_pread( ntfs_attr *na, s64 pos, s64 count, void *b )
{
s64 br, to_read, ofs, total, total2;
u64 cb_size_mask;
VCN start_vcn, vcn, end_vcn;
ntfs_volume *vol;
runlist_element *rl;
u8 *dest, *cb, *cb_pos, *cb_end;
u32 cb_size;
int err;
ATTR_FLAGS data_flags;
FILE_ATTR_FLAGS compression;
unsigned int nr_cbs, cb_clusters;
ntfs_log_trace( "Entering for inode 0x%llx, attr 0x%x, pos 0x%llx, count 0x%llx.\n",
( unsigned long long )na->ni->mft_no, na->type,
( long long )pos, ( long long )count );
data_flags = na->data_flags;
compression = na->ni->flags & FILE_ATTR_COMPRESSED;
if ( !na || !na->ni || !na->ni->vol || !b
|| ( ( data_flags & ATTR_COMPRESSION_MASK )
!= ATTR_IS_COMPRESSED )
|| pos < 0 || count < 0 )
{
errno = EINVAL;
return -1;
}
/*
* Encrypted attributes are not supported. We return access denied,
* which is what Windows NT4 does, too.
*/
if ( NAttrEncrypted( na ) )
{
errno = EACCES;
return -1;
}
if ( !count )
return 0;
/* Truncate reads beyond end of attribute. */
if ( pos + count > na->data_size )
{
if ( pos >= na->data_size )
{
return 0;
}
count = na->data_size - pos;
}
/* If it is a resident attribute, simply use ntfs_attr_pread(). */
if ( !NAttrNonResident( na ) )
return ntfs_attr_pread( na, pos, count, b );
total = total2 = 0;
/* Zero out reads beyond initialized size. */
if ( pos + count > na->initialized_size )
{
if ( pos >= na->initialized_size )
{
memset( b, 0, count );
return count;
}
total2 = pos + count - na->initialized_size;
count -= total2;
memset( ( u8* )b + count, 0, total2 );
}
vol = na->ni->vol;
cb_size = na->compression_block_size;
cb_size_mask = cb_size - 1UL;
cb_clusters = na->compression_block_clusters;
/* Need a temporary buffer for each loaded compression block. */
cb = ( u8* )ntfs_malloc( cb_size );
if ( !cb )
return -1;
/* Need a temporary buffer for each uncompressed block. */
dest = ( u8* )ntfs_malloc( cb_size );
if ( !dest )
{
free( cb );
return -1;
}
/*
* The first vcn in the first compression block (cb) which we need to
* decompress.
*/
start_vcn = ( pos & ~cb_size_mask ) >> vol->cluster_size_bits;
/* Offset in the uncompressed cb at which to start reading data. */
ofs = pos & cb_size_mask;
/*
* The first vcn in the cb after the last cb which we need to
* decompress.
*/
end_vcn = ( ( pos + count + cb_size - 1 ) & ~cb_size_mask ) >>
vol->cluster_size_bits;
/* Number of compression blocks (cbs) in the wanted vcn range. */
nr_cbs = ( end_vcn - start_vcn ) << vol->cluster_size_bits >>
na->compression_block_size_bits;
cb_end = cb + cb_size;
do_next_cb:
nr_cbs--;
cb_pos = cb;
vcn = start_vcn;
start_vcn += cb_clusters;
/* Check whether the compression block is sparse. */
rl = ntfs_attr_find_vcn( na, vcn );
if ( !rl || rl->lcn < LCN_HOLE )
{
free( cb );
free( dest );
if ( total )
return total;
/* FIXME: Do we want EIO or the error code? (AIA) */
errno = EIO;
return -1;
}
if ( rl->lcn == LCN_HOLE )
{
/* Sparse cb, zero out destination range overlapping the cb. */
ntfs_log_debug( "Found sparse compression block.\n" );
to_read = min( count, cb_size - ofs );
memset( b, 0, to_read );
ofs = 0;
total += to_read;
count -= to_read;
b = ( u8* )b + to_read;
}
else if ( !ntfs_is_cb_compressed( na, rl, vcn, cb_clusters ) )
{
s64 tdata_size, tinitialized_size;
/*
* Uncompressed cb, read it straight into the destination range
* overlapping the cb.
*/
ntfs_log_debug( "Found uncompressed compression block.\n" );
/*
* Read the uncompressed data into the destination buffer.
* NOTE: We cheat a little bit here by marking the attribute as
* not compressed in the ntfs_attr structure so that we can
* read the data by simply using ntfs_attr_pread(). (-8
* NOTE: we have to modify data_size and initialized_size
* temporarily as well...
*/
to_read = min( count, cb_size - ofs );
ofs += vcn << vol->cluster_size_bits;
NAttrClearCompressed( na );
na->data_flags &= ~ATTR_COMPRESSION_MASK;
tdata_size = na->data_size;
tinitialized_size = na->initialized_size;
na->data_size = na->initialized_size = na->allocated_size;
do
{
br = ntfs_attr_pread( na, ofs, to_read, b );
if ( br <= 0 )
{
if ( !br )
{
ntfs_log_error( "Failed to read an"
" uncompressed cluster,"
" inode %lld offs 0x%llx\n",
( long long )na->ni->mft_no,
( long long )ofs );
errno = EIO;
}
err = errno;
na->data_size = tdata_size;
na->initialized_size = tinitialized_size;
na->ni->flags |= compression;
na->data_flags = data_flags;
free( cb );
free( dest );
if ( total )
return total;
errno = err;
return br;
}
total += br;
count -= br;
b = ( u8* )b + br;
to_read -= br;
ofs += br;
}
while ( to_read > 0 );
na->data_size = tdata_size;
na->initialized_size = tinitialized_size;
na->ni->flags |= compression;
na->data_flags = data_flags;
ofs = 0;
}
else
{
s64 tdata_size, tinitialized_size;
/*
* Compressed cb, decompress it into the temporary buffer, then
* copy the data to the destination range overlapping the cb.
*/
ntfs_log_debug( "Found compressed compression block.\n" );
/*
* Read the compressed data into the temporary buffer.
* NOTE: We cheat a little bit here by marking the attribute as
* not compressed in the ntfs_attr structure so that we can
* read the raw, compressed data by simply using
* ntfs_attr_pread(). (-8
* NOTE: We have to modify data_size and initialized_size
* temporarily as well...
*/
to_read = cb_size;
NAttrClearCompressed( na );
na->data_flags &= ~ATTR_COMPRESSION_MASK;
tdata_size = na->data_size;
tinitialized_size = na->initialized_size;
na->data_size = na->initialized_size = na->allocated_size;
do
{
br = ntfs_attr_pread( na,
( vcn << vol->cluster_size_bits ) +
( cb_pos - cb ), to_read, cb_pos );
if ( br <= 0 )
{
if ( !br )
{
ntfs_log_error( "Failed to read a"
" compressed cluster, "
" inode %lld offs 0x%llx\n",
( long long )na->ni->mft_no,
( long long )( vcn << vol->cluster_size_bits ) );
errno = EIO;
}
err = errno;
na->data_size = tdata_size;
na->initialized_size = tinitialized_size;
na->ni->flags |= compression;
na->data_flags = data_flags;
free( cb );
free( dest );
if ( total )
return total;
errno = err;
return br;
}
cb_pos += br;
to_read -= br;
}
while ( to_read > 0 );
na->data_size = tdata_size;
na->initialized_size = tinitialized_size;
na->ni->flags |= compression;
na->data_flags = data_flags;
/* Just a precaution. */
if ( cb_pos + 2 <= cb_end )
*( u16* )cb_pos = 0;
ntfs_log_debug( "Successfully read the compression block.\n" );
if ( ntfs_decompress( dest, cb_size, cb, cb_size ) < 0 )
{
err = errno;
free( cb );
free( dest );
if ( total )
return total;
errno = err;
return -1;
}
to_read = min( count, cb_size - ofs );
memcpy( b, dest + ofs, to_read );
total += to_read;
count -= to_read;
b = ( u8* )b + to_read;
ofs = 0;
}
/* Do we have more work to do? */
if ( nr_cbs )
goto do_next_cb;
/* We no longer need the buffers. */
free( cb );
free( dest );
/* Return number of bytes read. */
return total + total2;
}
/*
* Read data from a set of clusters
*
* Returns the amount of data read
*/
static u32 read_clusters( ntfs_volume *vol, const runlist_element *rl,
s64 offs, u32 to_read, char *inbuf )
{
u32 count;
int xgot;
u32 got;
s64 xpos;
BOOL first;
char *xinbuf;
const runlist_element *xrl;
got = 0;
xrl = rl;
xinbuf = inbuf;
first = TRUE;
do
{
count = xrl->length << vol->cluster_size_bits;
xpos = xrl->lcn << vol->cluster_size_bits;
if ( first )
{
count -= offs;
xpos += offs;
}
if ( ( to_read - got ) < count )
count = to_read - got;
xgot = ntfs_pread( vol->dev, xpos, count, xinbuf );
if ( xgot == ( int )count )
{
got += count;
xpos += count;
xinbuf += count;
xrl++;
}
first = FALSE;
}
while ( ( xgot == ( int )count ) && ( got < to_read ) );
return ( got );
}
/*
* Write data to a set of clusters
*
* Returns the amount of data written
*/
static s32 write_clusters( ntfs_volume *vol, const runlist_element *rl,
s64 offs, s32 to_write, const char *outbuf )
{
s32 count;
s32 put, xput;
s64 xpos;
BOOL first;
const char *xoutbuf;
const runlist_element *xrl;
put = 0;
xrl = rl;
xoutbuf = outbuf;
first = TRUE;
do
{
count = xrl->length << vol->cluster_size_bits;
xpos = xrl->lcn << vol->cluster_size_bits;
if ( first )
{
count -= offs;
xpos += offs;
}
if ( ( to_write - put ) < count )
count = to_write - put;
xput = ntfs_pwrite( vol->dev, xpos, count, xoutbuf );
if ( xput == count )
{
put += count;
xpos += count;
xoutbuf += count;
xrl++;
}
first = FALSE;
}
while ( ( xput == count ) && ( put < to_write ) );
return ( put );
}
/*
* Compress and write a set of blocks
*
* returns the size actually written (rounded to a full cluster)
* or 0 if all zeroes (nothing is written)
* or -1 if could not compress (nothing is written)
* or -2 if there were an irrecoverable error (errno set)
*/
static s32 ntfs_comp_set( ntfs_attr *na, runlist_element *rl,
s64 offs, u32 insz, const char *inbuf )
{
ntfs_volume *vol;
char *outbuf;
char *pbuf;
u32 compsz;
s32 written;
s32 rounded;
unsigned int clsz;
u32 p;
unsigned int sz;
unsigned int bsz;
BOOL fail;
BOOL allzeroes;
/* a single compressed zero */
static char onezero[] = { 0x01, 0xb0, 0x00, 0x00 } ;
/* a couple of compressed zeroes */
static char twozeroes[] = { 0x02, 0xb0, 0x00, 0x00, 0x00 } ;
/* more compressed zeroes, to be followed by some count */
static char morezeroes[] = { 0x03, 0xb0, 0x02, 0x00 } ;
vol = na->ni->vol;
written = -1; /* default return */
clsz = 1 << vol->cluster_size_bits;
/* may need 2 extra bytes per block and 2 more bytes */
outbuf = ( char* )ntfs_malloc( na->compression_block_size
+ 2 * ( na->compression_block_size / NTFS_SB_SIZE )
+ 2 );
if ( outbuf )
{
fail = FALSE;
compsz = 0;
allzeroes = TRUE;
for ( p = 0; ( p < insz ) && !fail; p += NTFS_SB_SIZE )
{
if ( ( p + NTFS_SB_SIZE ) < insz )
bsz = NTFS_SB_SIZE;
else
bsz = insz - p;
pbuf = &outbuf[compsz];
sz = ntfs_compress_block( &inbuf[p], bsz, pbuf );
/* fail if all the clusters (or more) are needed */
if ( !sz || ( ( compsz + sz + clsz + 2 )
> na->compression_block_size ) )
fail = TRUE;
else
{
if ( allzeroes )
{
/* check whether this is all zeroes */
switch ( sz )
{
case 4 :
allzeroes = !memcmp(
pbuf, onezero, 4 );
break;
case 5 :
allzeroes = !memcmp(
pbuf, twozeroes, 5 );
break;
case 6 :
allzeroes = !memcmp(
pbuf, morezeroes, 4 );
break;
default :
allzeroes = FALSE;
break;
}
}
compsz += sz;
}
}
if ( !fail && !allzeroes )
{
/* add a couple of null bytes, space has been checked */
outbuf[compsz++] = 0;
outbuf[compsz++] = 0;
/* write a full cluster, to avoid partial reading */
rounded = ( ( compsz - 1 ) | ( clsz - 1 ) ) + 1;
written = write_clusters( vol, rl, offs, rounded, outbuf );
if ( written != rounded )
{
/*
* TODO : previously written text has been
* spoilt, should return a specific error
*/
ntfs_log_error( "error writing compressed data\n" );
errno = EIO;
written = -2;
}
}
else if ( !fail )
written = 0;
free( outbuf );
}
return ( written );
}
/*
* Check the validity of a compressed runlist
* The check starts at the beginning of current run and ends
* at the end of runlist
* errno is set if the runlist is not valid
*/
static BOOL valid_compressed_run( ntfs_attr *na, runlist_element *rl,
BOOL fullcheck, const char *text )
{
runlist_element *xrl;
const char *err;
BOOL ok = TRUE;
xrl = rl;
while ( xrl->vcn & ( na->compression_block_clusters - 1 ) )
xrl--;
err = ( const char* )NULL;
while ( xrl->length )
{
if ( ( xrl->vcn + xrl->length ) != xrl[1].vcn )
err = "Runs not adjacent";
if ( xrl->lcn == LCN_HOLE )
{
if ( ( xrl->vcn + xrl->length )
& ( na->compression_block_clusters - 1 ) )
{
err = "Invalid hole";
}
if ( fullcheck && ( xrl[1].lcn == LCN_HOLE ) )
{
err = "Adjacent holes";
}
}
if ( err )
{
ntfs_log_error( "%s at %s index %ld inode %lld\n",
err, text, ( long )( xrl - na->rl ),
( long long )na->ni->mft_no );
errno = EIO;
ok = FALSE;
err = ( const char* )NULL;
}
xrl++;
}
return ( ok );
}
/*
* Free unneeded clusters after overwriting compressed data
*
* This generally requires one or two empty slots at the end of runlist,
* but we do not want to reallocate the runlist here because
* there are many pointers to it.
* So the empty slots have to be reserved beforehand
*
* Returns zero unless some error occurred (described by errno)
*
* +======= start of block =====+
* 0 |A chunk may overflow | <-- rl usedcnt : A + B
* |A on previous block | then B
* |A |
* +-- end of allocated chunk --+ freelength : C
* |B | (incl overflow)
* +== end of compressed data ==+
* |C | <-- freerl freecnt : C + D
* |C chunk may overflow |
* |C on next block |
* +-- end of allocated chunk --+
* |D |
* |D chunk may overflow |
* 15 |D on next block |
* +======== end of block ======+
*
*/
static int ntfs_compress_overwr_free( ntfs_attr *na, runlist_element *rl,
s32 usedcnt, s32 freecnt, VCN *update_from )
{
BOOL beginhole;
BOOL mergeholes;
s32 oldlength;
s32 freelength;
s64 freelcn;
s64 freevcn;
runlist_element *freerl;
ntfs_volume *vol;
s32 carry;
int res;
vol = na->ni->vol;
res = 0;
freelcn = rl->lcn + usedcnt;
freevcn = rl->vcn + usedcnt;
freelength = rl->length - usedcnt;
beginhole = !usedcnt && !rl->vcn;
/* can merge with hole before ? */
mergeholes = !usedcnt
&& rl[0].vcn
&& ( rl[-1].lcn == LCN_HOLE );
/* truncate current run, carry to subsequent hole */
carry = freelength;
oldlength = rl->length;
if ( mergeholes )
{
/* merging with a hole before */
freerl = rl;
}
else
{
rl->length -= freelength; /* warning : can be zero */
freerl = ++rl;
}
if ( !mergeholes && ( usedcnt || beginhole ) )
{
s32 freed;
runlist_element *frl;
runlist_element *erl;
int holes = 0;
BOOL threeparts;
/* free the unneeded clusters from initial run, then freerl */
threeparts = ( freelength > freecnt );
freed = 0;
frl = freerl;
if ( freelength )
{
res = ntfs_cluster_free_basic( vol, freelcn,
( threeparts ? freecnt : freelength ) );
if ( !res )
freed += ( threeparts ? freecnt : freelength );
if ( !usedcnt )
{
holes++;
freerl--;
freerl->length += ( threeparts
? freecnt : freelength );
if ( freerl->vcn < *update_from )
*update_from = freerl->vcn;
}
}
while ( !res && frl->length && ( freed < freecnt ) )
{
if ( frl->length <= ( freecnt - freed ) )
{
res = ntfs_cluster_free_basic( vol, frl->lcn,
frl->length );
if ( !res )
{
freed += frl->length;
frl->lcn = LCN_HOLE;
frl->length += carry;
carry = 0;
holes++;
}
}
else
{
res = ntfs_cluster_free_basic( vol, frl->lcn,
freecnt - freed );
if ( !res )
{
frl->lcn += freecnt - freed;
frl->vcn += freecnt - freed;
frl->length -= freecnt - freed;
freed = freecnt;
}
}
frl++;
}
na->compressed_size -= freed << vol->cluster_size_bits;
switch ( holes )
{
case 0 :
/* there are no hole, must insert one */
/* space for hole has been prereserved */
if ( freerl->lcn == LCN_HOLE )
{
if ( threeparts )
{
erl = freerl;
while ( erl->length )
erl++;
do
{
erl[2] = *erl;
}
while ( erl-- != freerl );
freerl[1].length = freelength - freecnt;
freerl->length = freecnt;
freerl[1].lcn = freelcn + freecnt;
freerl[1].vcn = freevcn + freecnt;
freerl[2].lcn = LCN_HOLE;
freerl[2].vcn = freerl[1].vcn
+ freerl[1].length;
freerl->vcn = freevcn;
}
else
{
freerl->vcn = freevcn;
freerl->length += freelength;
}
}
else
{
erl = freerl;
while ( erl->length )
erl++;
if ( threeparts )
{
do
{
erl[2] = *erl;
}
while ( erl-- != freerl );
freerl[1].lcn = freelcn + freecnt;
freerl[1].vcn = freevcn + freecnt;
freerl[1].length = oldlength - usedcnt - freecnt;
}
else
{
do
{
erl[1] = *erl;
}
while ( erl-- != freerl );
}
freerl->lcn = LCN_HOLE;
freerl->vcn = freevcn;
freerl->length = freecnt;
}
break;
case 1 :
/* there is a single hole, may have to merge */
freerl->vcn = freevcn;
if ( freerl[1].lcn == LCN_HOLE )
{
freerl->length += freerl[1].length;
erl = freerl;
do
{
erl++;
*erl = erl[1];
}
while ( erl->length );
}
break;
default :
/* there were several holes, must merge them */
freerl->lcn = LCN_HOLE;
freerl->vcn = freevcn;
freerl->length = freecnt;
if ( freerl[holes].lcn == LCN_HOLE )
{
freerl->length += freerl[holes].length;
holes++;
}
erl = freerl;
do
{
erl++;
*erl = erl[holes - 1];
}
while ( erl->length );
break;
}
}
else
{
s32 freed;
runlist_element *frl;
runlist_element *xrl;
freed = 0;
frl = freerl--;
if ( freerl->vcn < *update_from )
*update_from = freerl->vcn;
while ( !res && frl->length && ( freed < freecnt ) )
{
if ( frl->length <= ( freecnt - freed ) )
{
freerl->length += frl->length;
freed += frl->length;
res = ntfs_cluster_free_basic( vol, frl->lcn,
frl->length );
frl++;
}
else
{
freerl->length += freecnt - freed;
res = ntfs_cluster_free_basic( vol, frl->lcn,
freecnt - freed );
frl->lcn += freecnt - freed;
frl->vcn += freecnt - freed;
frl->length -= freecnt - freed;
freed = freecnt;
}
}
/* remove unneded runlist entries */
xrl = freerl;
/* group with next run if also a hole */
if ( frl->length && ( frl->lcn == LCN_HOLE ) )
{
xrl->length += frl->length;
frl++;
}
while ( frl->length )
{
*++xrl = *frl++;
}
*++xrl = *frl; /* terminator */
na->compressed_size -= freed << vol->cluster_size_bits;
}
return ( res );
}
/*
* Free unneeded clusters after compression
*
* This generally requires one or two empty slots at the end of runlist,
* but we do not want to reallocate the runlist here because
* there are many pointers to it.
* So the empty slots have to be reserved beforehand
*
* Returns zero unless some error occurred (described by errno)
*/
static int ntfs_compress_free( ntfs_attr *na, runlist_element *rl,
s64 used, s64 reserved, BOOL appending,
VCN *update_from )
{
s32 freecnt;
s32 usedcnt;
int res;
s64 freelcn;
s64 freevcn;
s32 freelength;
BOOL mergeholes;
BOOL beginhole;
ntfs_volume *vol;
runlist_element *freerl;
res = -1; /* default return */
vol = na->ni->vol;
freecnt = ( reserved - used ) >> vol->cluster_size_bits;
usedcnt = ( reserved >> vol->cluster_size_bits ) - freecnt;
if ( rl->vcn < *update_from )
*update_from = rl->vcn;
/* skip entries fully used, if any */
while ( rl->length && ( rl->length < usedcnt ) )
{
usedcnt -= rl->length; /* must be > 0 */
rl++;
}
if ( rl->length )
{
/*
* Splitting the current allocation block requires
* an extra runlist element to create the hole.
* The required entry has been prereserved when
* mapping the runlist.
*/
/* get the free part in initial run */
freelcn = rl->lcn + usedcnt;
freevcn = rl->vcn + usedcnt;
/* new count of allocated clusters */
if ( !( ( freevcn + freecnt )
& ( na->compression_block_clusters - 1 ) ) )
{
if ( !appending )
res = ntfs_compress_overwr_free( na, rl,
usedcnt, freecnt, update_from );
else
{
freelength = rl->length - usedcnt;
beginhole = !usedcnt && !rl->vcn;
mergeholes = !usedcnt
&& rl[0].vcn
&& ( rl[-1].lcn == LCN_HOLE );
if ( mergeholes )
{
s32 carry;
/* shorten the runs which have free space */
carry = freecnt;
freerl = rl;
while ( freerl->length < carry )
{
carry -= freerl->length;
freerl++;
}
freerl->length = carry;
freerl = rl;
}
else
{
rl->length = usedcnt; /* can be zero ? */
freerl = ++rl;
}
if ( ( freelength > 0 )
&& !mergeholes
&& ( usedcnt || beginhole ) )
{
/*
* move the unused part to the end. Doing so,
* the vcn will be out of order. This does
* not harm, the vcn are meaningless now, and
* only the lcn are meaningful for freeing.
*/
/* locate current end */
while ( rl->length )
rl++;
/* new terminator relocated */
rl[1].vcn = rl->vcn;
rl[1].lcn = LCN_ENOENT;
rl[1].length = 0;
/* hole, currently allocated */
rl->vcn = freevcn;
rl->lcn = freelcn;
rl->length = freelength;
}
else
{
/* why is this different from the begin hole case ? */
if ( ( freelength > 0 )
&& !mergeholes
&& !usedcnt )
{
freerl--;
freerl->length = freelength;
if ( freerl->vcn < *update_from )
*update_from
= freerl->vcn;
}
}
/* free the hole */
res = ntfs_cluster_free_from_rl( vol, freerl );
if ( !res )
{
na->compressed_size -= freecnt
<< vol->cluster_size_bits;
if ( mergeholes )
{
/* merge with adjacent hole */
freerl--;
freerl->length += freecnt;
}
else
{
if ( beginhole )
freerl--;
/* mark hole as free */
freerl->lcn = LCN_HOLE;
freerl->vcn = freevcn;
freerl->length = freecnt;
}
if ( freerl->vcn < *update_from )
*update_from = freerl->vcn;
/* and set up the new end */
freerl[1].lcn = LCN_ENOENT;
freerl[1].vcn = freevcn + freecnt;
freerl[1].length = 0;
}
}
}
else
{
ntfs_log_error( "Bad end of a compression block set\n" );
errno = EIO;
}
}
else
{
ntfs_log_error( "No cluster to free after compression\n" );
errno = EIO;
}
return ( res );
}
/*
* Read existing data, decompress and append buffer
* Do nothing if something fails
*/
static int ntfs_read_append( ntfs_attr *na, const runlist_element *rl,
s64 offs, u32 compsz, s32 pos, BOOL appending,
char *outbuf, s64 to_write, const void *b )
{
int fail = 1;
char *compbuf;
u32 decompsz;
u32 got;
if ( compsz == na->compression_block_size )
{
/* if the full block was requested, it was a hole */
memset( outbuf, 0, compsz );
memcpy( &outbuf[pos], b, to_write );
fail = 0;
}
else
{
compbuf = ( char* )ntfs_malloc( compsz );
if ( compbuf )
{
/* must align to full block for decompression */
if ( appending )
decompsz = ( ( pos - 1 ) | ( NTFS_SB_SIZE - 1 ) ) + 1;
else
decompsz = na->compression_block_size;
got = read_clusters( na->ni->vol, rl, offs,
compsz, compbuf );
if ( ( got == compsz )
&& !ntfs_decompress( ( u8* )outbuf, decompsz,
( u8* )compbuf, compsz ) )
{
memcpy( &outbuf[pos], b, to_write );
fail = 0;
}
free( compbuf );
}
}
return ( fail );
}
/*
* Flush a full compression block
*
* returns the size actually written (rounded to a full cluster)
* or 0 if could not compress (and written uncompressed)
* or -1 if there were an irrecoverable error (errno set)
*/
static int ntfs_flush( ntfs_attr *na, runlist_element *rl, s64 offs,
const char *outbuf, s32 count, BOOL compress,
BOOL appending, VCN *update_from )
{
int rounded;
int written;
int clsz;
if ( compress )
{
written = ntfs_comp_set( na, rl, offs, count, outbuf );
if ( written == -1 )
compress = FALSE;
if ( ( written >= 0 )
&& ntfs_compress_free( na, rl, offs + written,
offs + na->compression_block_size, appending,
update_from ) )
written = -1;
}
else
written = 0;
if ( !compress )
{
clsz = 1 << na->ni->vol->cluster_size_bits;
rounded = ( ( count - 1 ) | ( clsz - 1 ) ) + 1;
written = write_clusters( na->ni->vol, rl,
offs, rounded, outbuf );
if ( written != rounded )
written = -1;
}
return ( written );
}
/*
* Write some data to be compressed.
* Compression only occurs when a few clusters (usually 16) are
* full. When this occurs an extra runlist slot may be needed, so
* it has to be reserved beforehand.
*
* Returns the size of uncompressed data written,
* or negative if an error occurred.
* When the returned size is less than requested, new clusters have
* to be allocated before the function is called again.
*/
s64 ntfs_compressed_pwrite( ntfs_attr *na, runlist_element *wrl, s64 wpos,
s64 offs, s64 to_write, s64 rounded,
const void *b, int compressed_part,
VCN *update_from )
{
ntfs_volume *vol;
runlist_element *brl; /* entry containing the beginning of block */
int compression_length;
s64 written;
s64 to_read;
s64 to_flush;
s64 roffs;
s64 got;
s64 start_vcn;
s64 nextblock;
s64 endwrite;
u32 compsz;
char *inbuf;
char *outbuf;
BOOL fail;
BOOL done;
BOOL compress;
BOOL appending;
if ( !valid_compressed_run( na, wrl, FALSE, "begin compressed write" ) )
{
return ( -1 );
}
if ( ( *update_from < 0 )
|| ( compressed_part < 0 )
|| ( compressed_part > ( int )na->compression_block_clusters ) )
{
ntfs_log_error( "Bad update vcn or compressed_part %d for compressed write\n",
compressed_part );
errno = EIO;
return ( -1 );
}
/* make sure there are two unused entries in runlist */
if ( na->unused_runs < 2 )
{
ntfs_log_error( "No unused runs for compressed write\n" );
errno = EIO;
return ( -1 );
}
if ( wrl->vcn < *update_from )
*update_from = wrl->vcn;
written = -1; /* default return */
vol = na->ni->vol;
compression_length = na->compression_block_clusters;
compress = FALSE;
done = FALSE;
/*
* Cannot accept writing beyond the current compression set
* because when compression occurs, clusters are freed
* and have to be reallocated.
* (cannot happen with standard fuse 4K buffers)
* Caller has to avoid this situation, or face consequences.
*/
nextblock = ( ( offs + ( wrl->vcn << vol->cluster_size_bits ) )
| ( na->compression_block_size - 1 ) ) + 1;
/* determine whether we are appending to file */
endwrite = offs + to_write + ( wrl->vcn << vol->cluster_size_bits );
appending = endwrite >= na->initialized_size;
if ( endwrite >= nextblock )
{
/* it is time to compress */
compress = TRUE;
/* only process what we can */
to_write = rounded = nextblock
- ( offs + ( wrl->vcn << vol->cluster_size_bits ) );
}
start_vcn = 0;
fail = FALSE;
brl = wrl;
roffs = 0;
/*
* If we are about to compress or we need to decompress
* existing data, we have to process a full set of blocks.
* So relocate the parameters to the beginning of allocation
* containing the first byte of the set of blocks.
*/
if ( compress || compressed_part )
{
/* find the beginning of block */
start_vcn = ( wrl->vcn + ( offs >> vol->cluster_size_bits ) )
& -compression_length;
if ( start_vcn < *update_from )
*update_from = start_vcn;
while ( brl->vcn && ( brl->vcn > start_vcn ) )
{
/* jumping back a hole means big trouble */
if ( brl->lcn == ( LCN )LCN_HOLE )
{
ntfs_log_error( "jump back over a hole when appending\n" );
fail = TRUE;
errno = EIO;
}
brl--;
offs += brl->length << vol->cluster_size_bits;
}
roffs = ( start_vcn - brl->vcn ) << vol->cluster_size_bits;
}
if ( compressed_part && !fail )
{
/*
* The set of compression blocks contains compressed data
* (we are reopening an existing file to append to it)
* Decompress the data and append
*/
compsz = compressed_part << vol->cluster_size_bits;
outbuf = ( char* )ntfs_malloc( na->compression_block_size );
if ( outbuf )
{
if ( appending )
{
to_read = offs - roffs;
to_flush = to_read + to_write;
}
else
{
to_read = na->data_size
- ( brl->vcn << vol->cluster_size_bits );
if ( to_read > na->compression_block_size )
to_read = na->compression_block_size;
to_flush = to_read;
}
if ( !ntfs_read_append( na, brl, roffs, compsz,
( s32 )( offs - roffs ), appending,
outbuf, to_write, b ) )
{
written = ntfs_flush( na, brl, roffs,
outbuf, to_flush, compress, appending,
update_from );
if ( written >= 0 )
{
written = to_write;
done = TRUE;
}
}
free( outbuf );
}
}
else
{
if ( compress && !fail )
{
/*
* we are filling up a block, read the full set
* of blocks and compress it
*/
inbuf = ( char* )ntfs_malloc( na->compression_block_size );
if ( inbuf )
{
to_read = offs - roffs;
if ( to_read )
got = read_clusters( vol, brl, roffs,
to_read, inbuf );
else
got = 0;
if ( got == to_read )
{
memcpy( &inbuf[to_read], b, to_write );
written = ntfs_comp_set( na, brl, roffs,
to_read + to_write, inbuf );
/*
* if compression was not successful,
* only write the part which was requested
*/
if ( ( written >= 0 )
/* free the unused clusters */
&& !ntfs_compress_free( na, brl,
written + roffs,
na->compression_block_size
+ roffs,
appending, update_from ) )
{
done = TRUE;
written = to_write;
}
}
free( inbuf );
}
}
if ( !done )
{
/*
* if the compression block is not full, or
* if compression failed for whatever reason,
* write uncompressed
*/
/* check we are not overflowing current allocation */
if ( ( wpos + rounded )
> ( ( wrl->lcn + wrl->length )
<< vol->cluster_size_bits ) )
{
ntfs_log_error( "writing on unallocated clusters\n" );
errno = EIO;
}
else
{
written = ntfs_pwrite( vol->dev, wpos,
rounded, b );
if ( written == rounded )
written = to_write;
}
}
}
if ( ( written >= 0 )
&& !valid_compressed_run( na, wrl, TRUE, "end compressed write" ) )
written = -1;
return ( written );
}
/*
* Close a file written compressed.
* This compresses the last partial compression block of the file.
* Two empty runlist slots have to be reserved beforehand.
*
* Returns zero if closing is successful.
*/
int ntfs_compressed_close( ntfs_attr *na, runlist_element *wrl, s64 offs,
VCN *update_from )
{
ntfs_volume *vol;
runlist_element *brl; /* entry containing the beginning of block */
int compression_length;
s64 written;
s64 to_read;
s64 roffs;
s64 got;
s64 start_vcn;
char *inbuf;
BOOL fail;
BOOL done;
if ( na->unused_runs < 2 )
{
ntfs_log_error( "No unused runs for compressed close\n" );
errno = EIO;
return ( -1 );
}
if ( *update_from < 0 )
{
ntfs_log_error( "Bad update vcn for compressed close\n" );
errno = EIO;
return ( -1 );
}
if ( wrl->vcn < *update_from )
*update_from = wrl->vcn;
vol = na->ni->vol;
compression_length = na->compression_block_clusters;
done = FALSE;
/*
* There generally is an uncompressed block at end of file,
* read the full block and compress it
*/
inbuf = ( char* )ntfs_malloc( na->compression_block_size );
if ( inbuf )
{
start_vcn = ( wrl->vcn + ( offs >> vol->cluster_size_bits ) )
& -compression_length;
if ( start_vcn < *update_from )
*update_from = start_vcn;
to_read = offs + ( ( wrl->vcn - start_vcn )
<< vol->cluster_size_bits );
brl = wrl;
fail = FALSE;
while ( brl->vcn && ( brl->vcn > start_vcn ) )
{
if ( brl->lcn == ( LCN )LCN_HOLE )
{
ntfs_log_error( "jump back over a hole when closing\n" );
fail = TRUE;
errno = EIO;
}
brl--;
}
if ( !fail )
{
/* roffs can be an offset from another uncomp block */
roffs = ( start_vcn - brl->vcn )
<< vol->cluster_size_bits;
if ( to_read )
{
got = read_clusters( vol, brl, roffs, to_read,
inbuf );
if ( got == to_read )
{
written = ntfs_comp_set( na, brl, roffs,
to_read, inbuf );
if ( ( written >= 0 )
/* free the unused clusters */
&& !ntfs_compress_free( na, brl,
written + roffs,
na->compression_block_size + roffs,
TRUE, update_from ) )
{
done = TRUE;
}
else
/* if compression failed, leave uncompressed */
if ( written == -1 )
done = TRUE;
}
}
else
done = TRUE;
free( inbuf );
}
}
if ( done && !valid_compressed_run( na, wrl, TRUE, "end compressed close" ) )
done = FALSE;
return ( !done );
}
Reference in New Issue View Git Blame Copy Permalink