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usbloadergx/source/libntfs/runlist.c
giantpune 9e79c9d99b * remove little unused code 
* code cleanup
2010-09-18 23:16:05 +00:00

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/**
* runlist.c - Run list handling code. Originated from the Linux-NTFS project.
*
* Copyright (c) 2002-2005 Anton Altaparmakov
* Copyright (c) 2002-2005 Richard Russon
* Copyright (c) 2002-2008 Szabolcs Szakacsits
* Copyright (c) 2004 Yura Pakhuchiy
* Copyright (c) 2007-2009 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
*/
#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 "compat.h"
#include "types.h"
#include "volume.h"
#include "layout.h"
#include "debug.h"
#include "device.h"
#include "logging.h"
#include "misc.h"
/**
* ntfs_rl_mm - runlist memmove
* @base:
* @dst:
* @src:
* @size:
*
* Description...
*
* Returns:
*/
static void ntfs_rl_mm( runlist_element *base, int dst, int src, int size )
{
if ( ( dst != src ) && ( size > 0 ) )
memmove( base + dst, base + src, size * sizeof( *base ) );
}
/**
* ntfs_rl_mc - runlist memory copy
* @dstbase:
* @dst:
* @srcbase:
* @src:
* @size:
*
* Description...
*
* Returns:
*/
static void ntfs_rl_mc( runlist_element *dstbase, int dst,
runlist_element *srcbase, int src, int size )
{
if ( size > 0 )
memcpy( dstbase + dst, srcbase + src, size * sizeof( *dstbase ) );
}
/**
* ntfs_rl_realloc - Reallocate memory for runlists
* @rl: original runlist
* @old_size: number of runlist elements in the original runlist @rl
* @new_size: number of runlist elements we need space for
*
* As the runlists grow, more memory will be required. To prevent large
* numbers of small reallocations of memory, this function returns a 4kiB block
* of memory.
*
* N.B. If the new allocation doesn't require a different number of 4kiB
* blocks in memory, the function will return the original pointer.
*
* On success, return a pointer to the newly allocated, or recycled, memory.
* On error, return NULL with errno set to the error code.
*/
static runlist_element *ntfs_rl_realloc( runlist_element *rl, int old_size,
int new_size )
{
old_size = ( old_size * sizeof( runlist_element ) + 0xfff ) & ~0xfff;
new_size = ( new_size * sizeof( runlist_element ) + 0xfff ) & ~0xfff;
if ( old_size == new_size )
return rl;
return realloc( rl, new_size );
}
/*
* Extend a runlist by some entry count
* The runlist may have to be reallocated
*
* Returns the reallocated runlist
* or NULL if reallocation was not possible (with errno set)
* the runlist is left unchanged if the reallocation fails
*/
runlist_element *ntfs_rl_extend( ntfs_attr *na, runlist_element *rl,
int more_entries )
{
runlist_element *newrl;
int last;
int irl;
if ( na->rl && rl )
{
irl = ( int )( rl - na->rl );
last = irl;
while ( na->rl[last].length )
last++;
newrl = ntfs_rl_realloc( na->rl, last + 1, last + more_entries + 1 );
if ( !newrl )
{
errno = ENOMEM;
rl = ( runlist_element* )NULL;
}
else
na->rl = newrl;
rl = &newrl[irl];
}
else
{
ntfs_log_error( "Cannot extend unmapped runlist" );
errno = EIO;
rl = ( runlist_element* )NULL;
}
return ( rl );
}
/**
* ntfs_rl_are_mergeable - test if two runlists can be joined together
* @dst: original runlist
* @src: new runlist to test for mergeability with @dst
*
* Test if two runlists can be joined together. For this, their VCNs and LCNs
* must be adjacent.
*
* Return: TRUE Success, the runlists can be merged.
* FALSE Failure, the runlists cannot be merged.
*/
static BOOL ntfs_rl_are_mergeable( runlist_element *dst, runlist_element *src )
{
if ( !dst || !src )
{
ntfs_log_debug( "Eeek. ntfs_rl_are_mergeable() invoked with NULL "
"pointer!\n" );
return FALSE;
}
/* We can merge unmapped regions even if they are misaligned. */
if ( ( dst->lcn == LCN_RL_NOT_MAPPED ) && ( src->lcn == LCN_RL_NOT_MAPPED ) )
return TRUE;
/* If the runs are misaligned, we cannot merge them. */
if ( ( dst->vcn + dst->length ) != src->vcn )
return FALSE;
/* If both runs are non-sparse and contiguous, we can merge them. */
if ( ( dst->lcn >= 0 ) && ( src->lcn >= 0 ) &&
( ( dst->lcn + dst->length ) == src->lcn ) )
return TRUE;
/* If we are merging two holes, we can merge them. */
if ( ( dst->lcn == LCN_HOLE ) && ( src->lcn == LCN_HOLE ) )
return TRUE;
/* Cannot merge. */
return FALSE;
}
/**
* __ntfs_rl_merge - merge two runlists without testing if they can be merged
* @dst: original, destination runlist
* @src: new runlist to merge with @dst
*
* Merge the two runlists, writing into the destination runlist @dst. The
* caller must make sure the runlists can be merged or this will corrupt the
* destination runlist.
*/
static void __ntfs_rl_merge( runlist_element *dst, runlist_element *src )
{
dst->length += src->length;
}
/**
* ntfs_rl_append - append a runlist after a given element
* @dst: original runlist to be worked on
* @dsize: number of elements in @dst (including end marker)
* @src: runlist to be inserted into @dst
* @ssize: number of elements in @src (excluding end marker)
* @loc: append the new runlist @src after this element in @dst
*
* Append the runlist @src after element @loc in @dst. Merge the right end of
* the new runlist, if necessary. Adjust the size of the hole before the
* appended runlist.
*
* On success, return a pointer to the new, combined, runlist. Note, both
* runlists @dst and @src are deallocated before returning so you cannot use
* the pointers for anything any more. (Strictly speaking the returned runlist
* may be the same as @dst but this is irrelevant.)
*
* On error, return NULL, with errno set to the error code. Both runlists are
* left unmodified.
*/
static runlist_element *ntfs_rl_append( runlist_element *dst, int dsize,
runlist_element *src, int ssize, int loc )
{
BOOL right = FALSE; /* Right end of @src needs merging */
int marker; /* End of the inserted runs */
if ( !dst || !src )
{
ntfs_log_debug( "Eeek. ntfs_rl_append() invoked with NULL "
"pointer!\n" );
errno = EINVAL;
return NULL;
}
/* First, check if the right hand end needs merging. */
if ( ( loc + 1 ) < dsize )
right = ntfs_rl_are_mergeable( src + ssize - 1, dst + loc + 1 );
/* Space required: @dst size + @src size, less one if we merged. */
dst = ntfs_rl_realloc( dst, dsize, dsize + ssize - right );
if ( !dst )
return NULL;
/*
* We are guaranteed to succeed from here so can start modifying the
* original runlists.
*/
/* First, merge the right hand end, if necessary. */
if ( right )
__ntfs_rl_merge( src + ssize - 1, dst + loc + 1 );
/* marker - First run after the @src runs that have been inserted */
marker = loc + ssize + 1;
/* Move the tail of @dst out of the way, then copy in @src. */
ntfs_rl_mm( dst, marker, loc + 1 + right, dsize - loc - 1 - right );
ntfs_rl_mc( dst, loc + 1, src, 0, ssize );
/* Adjust the size of the preceding hole. */
dst[loc].length = dst[loc + 1].vcn - dst[loc].vcn;
/* We may have changed the length of the file, so fix the end marker */
if ( dst[marker].lcn == LCN_ENOENT )
dst[marker].vcn = dst[marker-1].vcn + dst[marker-1].length;
return dst;
}
/**
* ntfs_rl_insert - insert a runlist into another
* @dst: original runlist to be worked on
* @dsize: number of elements in @dst (including end marker)
* @src: new runlist to be inserted
* @ssize: number of elements in @src (excluding end marker)
* @loc: insert the new runlist @src before this element in @dst
*
* Insert the runlist @src before element @loc in the runlist @dst. Merge the
* left end of the new runlist, if necessary. Adjust the size of the hole
* after the inserted runlist.
*
* On success, return a pointer to the new, combined, runlist. Note, both
* runlists @dst and @src are deallocated before returning so you cannot use
* the pointers for anything any more. (Strictly speaking the returned runlist
* may be the same as @dst but this is irrelevant.)
*
* On error, return NULL, with errno set to the error code. Both runlists are
* left unmodified.
*/
static runlist_element *ntfs_rl_insert( runlist_element *dst, int dsize,
runlist_element *src, int ssize, int loc )
{
BOOL left = FALSE; /* Left end of @src needs merging */
BOOL disc = FALSE; /* Discontinuity between @dst and @src */
int marker; /* End of the inserted runs */
if ( !dst || !src )
{
ntfs_log_debug( "Eeek. ntfs_rl_insert() invoked with NULL "
"pointer!\n" );
errno = EINVAL;
return NULL;
}
/* disc => Discontinuity between the end of @dst and the start of @src.
* This means we might need to insert a "notmapped" run.
*/
if ( loc == 0 )
disc = ( src[0].vcn > 0 );
else
{
s64 merged_length;
left = ntfs_rl_are_mergeable( dst + loc - 1, src );
merged_length = dst[loc - 1].length;
if ( left )
merged_length += src->length;
disc = ( src[0].vcn > dst[loc - 1].vcn + merged_length );
}
/* Space required: @dst size + @src size, less one if we merged, plus
* one if there was a discontinuity.
*/
dst = ntfs_rl_realloc( dst, dsize, dsize + ssize - left + disc );
if ( !dst )
return NULL;
/*
* We are guaranteed to succeed from here so can start modifying the
* original runlist.
*/
if ( left )
__ntfs_rl_merge( dst + loc - 1, src );
/*
* marker - First run after the @src runs that have been inserted
* Nominally: marker = @loc + @ssize (location + number of runs in @src)
* If "left", then the first run in @src has been merged with one in @dst.
* If "disc", then @dst and @src don't meet and we need an extra run to fill the gap.
*/
marker = loc + ssize - left + disc;
/* Move the tail of @dst out of the way, then copy in @src. */
ntfs_rl_mm( dst, marker, loc, dsize - loc );
ntfs_rl_mc( dst, loc + disc, src, left, ssize - left );
/* Adjust the VCN of the first run after the insertion ... */
dst[marker].vcn = dst[marker - 1].vcn + dst[marker - 1].length;
/* ... and the length. */
if ( dst[marker].lcn == LCN_HOLE || dst[marker].lcn == LCN_RL_NOT_MAPPED )
dst[marker].length = dst[marker + 1].vcn - dst[marker].vcn;
/* Writing beyond the end of the file and there's a discontinuity. */
if ( disc )
{
if ( loc > 0 )
{
dst[loc].vcn = dst[loc - 1].vcn + dst[loc - 1].length;
dst[loc].length = dst[loc + 1].vcn - dst[loc].vcn;
}
else
{
dst[loc].vcn = 0;
dst[loc].length = dst[loc + 1].vcn;
}
dst[loc].lcn = LCN_RL_NOT_MAPPED;
}
return dst;
}
/**
* ntfs_rl_replace - overwrite a runlist element with another runlist
* @dst: original runlist to be worked on
* @dsize: number of elements in @dst (including end marker)
* @src: new runlist to be inserted
* @ssize: number of elements in @src (excluding end marker)
* @loc: index in runlist @dst to overwrite with @src
*
* Replace the runlist element @dst at @loc with @src. Merge the left and
* right ends of the inserted runlist, if necessary.
*
* On success, return a pointer to the new, combined, runlist. Note, both
* runlists @dst and @src are deallocated before returning so you cannot use
* the pointers for anything any more. (Strictly speaking the returned runlist
* may be the same as @dst but this is irrelevant.)
*
* On error, return NULL, with errno set to the error code. Both runlists are
* left unmodified.
*/
static runlist_element *ntfs_rl_replace( runlist_element *dst, int dsize,
runlist_element *src, int ssize,
int loc )
{
signed delta;
BOOL left = FALSE; /* Left end of @src needs merging */
BOOL right = FALSE; /* Right end of @src needs merging */
int tail; /* Start of tail of @dst */
int marker; /* End of the inserted runs */
if ( !dst || !src )
{
ntfs_log_debug( "Eeek. ntfs_rl_replace() invoked with NULL "
"pointer!\n" );
errno = EINVAL;
return NULL;
}
/* First, see if the left and right ends need merging. */
if ( ( loc + 1 ) < dsize )
right = ntfs_rl_are_mergeable( src + ssize - 1, dst + loc + 1 );
if ( loc > 0 )
left = ntfs_rl_are_mergeable( dst + loc - 1, src );
/* Allocate some space. We'll need less if the left, right, or both
* ends get merged. The -1 accounts for the run being replaced.
*/
delta = ssize - 1 - left - right;
if ( delta > 0 )
{
dst = ntfs_rl_realloc( dst, dsize, dsize + delta );
if ( !dst )
return NULL;
}
/*
* We are guaranteed to succeed from here so can start modifying the
* original runlists.
*/
/* First, merge the left and right ends, if necessary. */
if ( right )
__ntfs_rl_merge( src + ssize - 1, dst + loc + 1 );
if ( left )
__ntfs_rl_merge( dst + loc - 1, src );
/*
* tail - Offset of the tail of @dst
* Nominally: @tail = @loc + 1 (location, skipping the replaced run)
* If "right", then one of @dst's runs is already merged into @src.
*/
tail = loc + right + 1;
/*
* marker - First run after the @src runs that have been inserted
* Nominally: @marker = @loc + @ssize (location + number of runs in @src)
* If "left", then the first run in @src has been merged with one in @dst.
*/
marker = loc + ssize - left;
/* Move the tail of @dst out of the way, then copy in @src. */
ntfs_rl_mm( dst, marker, tail, dsize - tail );
ntfs_rl_mc( dst, loc, src, left, ssize - left );
/* We may have changed the length of the file, so fix the end marker */
if ( ( ( dsize - tail ) > 0 ) && ( dst[marker].lcn == LCN_ENOENT ) )
dst[marker].vcn = dst[marker - 1].vcn + dst[marker - 1].length;
return dst;
}
/**
* ntfs_rl_split - insert a runlist into the centre of a hole
* @dst: original runlist to be worked on
* @dsize: number of elements in @dst (including end marker)
* @src: new runlist to be inserted
* @ssize: number of elements in @src (excluding end marker)
* @loc: index in runlist @dst at which to split and insert @src
*
* Split the runlist @dst at @loc into two and insert @new in between the two
* fragments. No merging of runlists is necessary. Adjust the size of the
* holes either side.
*
* On success, return a pointer to the new, combined, runlist. Note, both
* runlists @dst and @src are deallocated before returning so you cannot use
* the pointers for anything any more. (Strictly speaking the returned runlist
* may be the same as @dst but this is irrelevant.)
*
* On error, return NULL, with errno set to the error code. Both runlists are
* left unmodified.
*/
static runlist_element *ntfs_rl_split( runlist_element *dst, int dsize,
runlist_element *src, int ssize, int loc )
{
if ( !dst || !src )
{
ntfs_log_debug( "Eeek. ntfs_rl_split() invoked with NULL pointer!\n" );
errno = EINVAL;
return NULL;
}
/* Space required: @dst size + @src size + one new hole. */
dst = ntfs_rl_realloc( dst, dsize, dsize + ssize + 1 );
if ( !dst )
return dst;
/*
* We are guaranteed to succeed from here so can start modifying the
* original runlists.
*/
/* Move the tail of @dst out of the way, then copy in @src. */
ntfs_rl_mm( dst, loc + 1 + ssize, loc, dsize - loc );
ntfs_rl_mc( dst, loc + 1, src, 0, ssize );
/* Adjust the size of the holes either size of @src. */
dst[loc].length = dst[loc+1].vcn - dst[loc].vcn;
dst[loc+ssize+1].vcn = dst[loc+ssize].vcn + dst[loc+ssize].length;
dst[loc+ssize+1].length = dst[loc+ssize+2].vcn - dst[loc+ssize+1].vcn;
return dst;
}
/**
* ntfs_runlists_merge_i - see ntfs_runlists_merge
*/
static runlist_element *ntfs_runlists_merge_i( runlist_element *drl,
runlist_element *srl )
{
int di, si; /* Current index into @[ds]rl. */
int sstart; /* First index with lcn > LCN_RL_NOT_MAPPED. */
int dins; /* Index into @drl at which to insert @srl. */
int dend, send; /* Last index into @[ds]rl. */
int dfinal, sfinal; /* The last index into @[ds]rl with
lcn >= LCN_HOLE. */
int marker = 0;
VCN marker_vcn = 0;
ntfs_log_debug( "dst:\n" );
ntfs_debug_runlist_dump( drl );
ntfs_log_debug( "src:\n" );
ntfs_debug_runlist_dump( srl );
/* Check for silly calling... */
if ( !srl )
return drl;
/* Check for the case where the first mapping is being done now. */
if ( !drl )
{
drl = srl;
/* Complete the source runlist if necessary. */
if ( drl[0].vcn )
{
/* Scan to the end of the source runlist. */
for ( dend = 0; drl[dend].length; dend++ )
;
dend++;
drl = ntfs_rl_realloc( drl, dend, dend + 1 );
if ( !drl )
return drl;
/* Insert start element at the front of the runlist. */
ntfs_rl_mm( drl, 1, 0, dend );
drl[0].vcn = 0;
drl[0].lcn = LCN_RL_NOT_MAPPED;
drl[0].length = drl[1].vcn;
}
goto finished;
}
si = di = 0;
/* Skip any unmapped start element(s) in the source runlist. */
while ( srl[si].length && srl[si].lcn < ( LCN )LCN_HOLE )
si++;
/* Can't have an entirely unmapped source runlist. */
if ( !srl[si].length )
{
errno = EINVAL;
ntfs_log_perror( "%s: unmapped source runlist", __FUNCTION__ );
return NULL;
}
/* Record the starting points. */
sstart = si;
/*
* Skip forward in @drl until we reach the position where @srl needs to
* be inserted. If we reach the end of @drl, @srl just needs to be
* appended to @drl.
*/
for ( ; drl[di].length; di++ )
{
if ( drl[di].vcn + drl[di].length > srl[sstart].vcn )
break;
}
dins = di;
/* Sanity check for illegal overlaps. */
if ( ( drl[di].vcn == srl[si].vcn ) && ( drl[di].lcn >= 0 ) &&
( srl[si].lcn >= 0 ) )
{
errno = ERANGE;
ntfs_log_perror( "Run lists overlap. Cannot merge" );
return NULL;
}
/* Scan to the end of both runlists in order to know their sizes. */
for ( send = si; srl[send].length; send++ )
;
for ( dend = di; drl[dend].length; dend++ )
;
if ( srl[send].lcn == ( LCN )LCN_ENOENT )
marker_vcn = srl[marker = send].vcn;
/* Scan to the last element with lcn >= LCN_HOLE. */
for ( sfinal = send; sfinal >= 0 && srl[sfinal].lcn < LCN_HOLE; sfinal-- )
;
for ( dfinal = dend; dfinal >= 0 && drl[dfinal].lcn < LCN_HOLE; dfinal-- )
;
{
BOOL start;
BOOL finish;
int ds = dend + 1; /* Number of elements in drl & srl */
int ss = sfinal - sstart + 1;
start = ( ( drl[dins].lcn < LCN_RL_NOT_MAPPED ) || /* End of file */
( drl[dins].vcn == srl[sstart].vcn ) ); /* Start of hole */
finish = ( ( drl[dins].lcn >= LCN_RL_NOT_MAPPED ) && /* End of file */
( ( drl[dins].vcn + drl[dins].length ) <= /* End of hole */
( srl[send - 1].vcn + srl[send - 1].length ) ) );
/* Or we'll lose an end marker */
if ( finish && !drl[dins].length )
ss++;
if ( marker && ( drl[dins].vcn + drl[dins].length > srl[send - 1].vcn ) )
finish = FALSE;
ntfs_log_debug( "dfinal = %i, dend = %i\n", dfinal, dend );
ntfs_log_debug( "sstart = %i, sfinal = %i, send = %i\n", sstart, sfinal, send );
ntfs_log_debug( "start = %i, finish = %i\n", start, finish );
ntfs_log_debug( "ds = %i, ss = %i, dins = %i\n", ds, ss, dins );
if ( start )
{
if ( finish )
drl = ntfs_rl_replace( drl, ds, srl + sstart, ss, dins );
else
drl = ntfs_rl_insert( drl, ds, srl + sstart, ss, dins );
}
else
{
if ( finish )
drl = ntfs_rl_append( drl, ds, srl + sstart, ss, dins );
else
drl = ntfs_rl_split( drl, ds, srl + sstart, ss, dins );
}
if ( !drl )
{
ntfs_log_perror( "Merge failed" );
return drl;
}
free( srl );
if ( marker )
{
ntfs_log_debug( "Triggering marker code.\n" );
for ( ds = dend; drl[ds].length; ds++ )
;
/* We only need to care if @srl ended after @drl. */
if ( drl[ds].vcn <= marker_vcn )
{
int slots = 0;
if ( drl[ds].vcn == marker_vcn )
{
ntfs_log_debug( "Old marker = %lli, replacing with "
"LCN_ENOENT.\n",
( long long )drl[ds].lcn );
drl[ds].lcn = ( LCN )LCN_ENOENT;
goto finished;
}
/*
* We need to create an unmapped runlist element in
* @drl or extend an existing one before adding the
* ENOENT terminator.
*/
if ( drl[ds].lcn == ( LCN )LCN_ENOENT )
{
ds--;
slots = 1;
}
if ( drl[ds].lcn != ( LCN )LCN_RL_NOT_MAPPED )
{
/* Add an unmapped runlist element. */
if ( !slots )
{
/* FIXME/TODO: We need to have the
* extra memory already! (AIA)
*/
drl = ntfs_rl_realloc( drl, ds, ds + 2 );
if ( !drl )
goto critical_error;
slots = 2;
}
ds++;
/* Need to set vcn if it isn't set already. */
if ( slots != 1 )
drl[ds].vcn = drl[ds - 1].vcn +
drl[ds - 1].length;
drl[ds].lcn = ( LCN )LCN_RL_NOT_MAPPED;
/* We now used up a slot. */
slots--;
}
drl[ds].length = marker_vcn - drl[ds].vcn;
/* Finally add the ENOENT terminator. */
ds++;
if ( !slots )
{
/* FIXME/TODO: We need to have the extra
* memory already! (AIA)
*/
drl = ntfs_rl_realloc( drl, ds, ds + 1 );
if ( !drl )
goto critical_error;
}
drl[ds].vcn = marker_vcn;
drl[ds].lcn = ( LCN )LCN_ENOENT;
drl[ds].length = ( s64 )0;
}
}
}
finished:
/* The merge was completed successfully. */
ntfs_log_debug( "Merged runlist:\n" );
ntfs_debug_runlist_dump( drl );
return drl;
critical_error:
/* Critical error! We cannot afford to fail here. */
ntfs_log_perror( "libntfs: Critical error" );
ntfs_log_debug( "Forcing segmentation fault!\n" );
marker_vcn = ( ( runlist* )NULL )->lcn;
return drl;
}
/**
* ntfs_runlists_merge - merge two runlists into one
* @drl: original runlist to be worked on
* @srl: new runlist to be merged into @drl
*
* First we sanity check the two runlists @srl and @drl to make sure that they
* are sensible and can be merged. The runlist @srl must be either after the
* runlist @drl or completely within a hole (or unmapped region) in @drl.
*
* Merging of runlists is necessary in two cases:
* 1. When attribute lists are used and a further extent is being mapped.
* 2. When new clusters are allocated to fill a hole or extend a file.
*
* There are four possible ways @srl can be merged. It can:
* - be inserted at the beginning of a hole,
* - split the hole in two and be inserted between the two fragments,
* - be appended at the end of a hole, or it can
* - replace the whole hole.
* It can also be appended to the end of the runlist, which is just a variant
* of the insert case.
*
* On success, return a pointer to the new, combined, runlist. Note, both
* runlists @drl and @srl are deallocated before returning so you cannot use
* the pointers for anything any more. (Strictly speaking the returned runlist
* may be the same as @dst but this is irrelevant.)
*
* On error, return NULL, with errno set to the error code. Both runlists are
* left unmodified. The following error codes are defined:
* ENOMEM Not enough memory to allocate runlist array.
* EINVAL Invalid parameters were passed in.
* ERANGE The runlists overlap and cannot be merged.
*/
runlist_element *ntfs_runlists_merge( runlist_element *drl,
runlist_element *srl )
{
runlist_element *rl;
ntfs_log_enter( "Entering\n" );
rl = ntfs_runlists_merge_i( drl, srl );
ntfs_log_leave( "\n" );
return rl;
}
/**
* ntfs_mapping_pairs_decompress - convert mapping pairs array to runlist
* @vol: ntfs volume on which the attribute resides
* @attr: attribute record whose mapping pairs array to decompress
* @old_rl: optional runlist in which to insert @attr's runlist
*
* Decompress the attribute @attr's mapping pairs array into a runlist. On
* success, return the decompressed runlist.
*
* If @old_rl is not NULL, decompressed runlist is inserted into the
* appropriate place in @old_rl and the resultant, combined runlist is
* returned. The original @old_rl is deallocated.
*
* On error, return NULL with errno set to the error code. @old_rl is left
* unmodified in that case.
*
* The following error codes are defined:
* ENOMEM Not enough memory to allocate runlist array.
* EIO Corrupt runlist.
* EINVAL Invalid parameters were passed in.
* ERANGE The two runlists overlap.
*
* FIXME: For now we take the conceptionally simplest approach of creating the
* new runlist disregarding the already existing one and then splicing the
* two into one, if that is possible (we check for overlap and discard the new
* runlist if overlap present before returning NULL, with errno = ERANGE).
*/
static runlist_element *ntfs_mapping_pairs_decompress_i( const ntfs_volume *vol,
const ATTR_RECORD *attr, runlist_element *old_rl )
{
VCN vcn; /* Current vcn. */
LCN lcn; /* Current lcn. */
s64 deltaxcn; /* Change in [vl]cn. */
runlist_element *rl; /* The output runlist. */
const u8 *buf; /* Current position in mapping pairs array. */
const u8 *attr_end; /* End of attribute. */
int err, rlsize; /* Size of runlist buffer. */
u16 rlpos; /* Current runlist position in units of
runlist_elements. */
u8 b; /* Current byte offset in buf. */
ntfs_log_trace( "Entering for attr 0x%x.\n",
( unsigned )le32_to_cpu( attr->type ) );
/* Make sure attr exists and is non-resident. */
if ( !attr || !attr->non_resident ||
sle64_to_cpu( attr->lowest_vcn ) < ( VCN )0 )
{
errno = EINVAL;
return NULL;
}
/* Start at vcn = lowest_vcn and lcn 0. */
vcn = sle64_to_cpu( attr->lowest_vcn );
lcn = 0;
/* Get start of the mapping pairs array. */
buf = ( const u8* )attr + le16_to_cpu( attr->mapping_pairs_offset );
attr_end = ( const u8* )attr + le32_to_cpu( attr->length );
if ( buf < ( const u8* )attr || buf > attr_end )
{
ntfs_log_debug( "Corrupt attribute.\n" );
errno = EIO;
return NULL;
}
/* Current position in runlist array. */
rlpos = 0;
/* Allocate first 4kiB block and set current runlist size to 4kiB. */
rlsize = 0x1000;
rl = ntfs_malloc( rlsize );
if ( !rl )
return NULL;
/* Insert unmapped starting element if necessary. */
if ( vcn )
{
rl->vcn = ( VCN )0;
rl->lcn = ( LCN )LCN_RL_NOT_MAPPED;
rl->length = vcn;
rlpos++;
}
while ( buf < attr_end && *buf )
{
/*
* Allocate more memory if needed, including space for the
* not-mapped and terminator elements.
*/
if ( ( int )( ( rlpos + 3 ) * sizeof( *old_rl ) ) > rlsize )
{
runlist_element *rl2;
rlsize += 0x1000;
rl2 = realloc( rl, rlsize );
if ( !rl2 )
{
int eo = errno;
free( rl );
errno = eo;
return NULL;
}
rl = rl2;
}
/* Enter the current vcn into the current runlist element. */
rl[rlpos].vcn = vcn;
/*
* Get the change in vcn, i.e. the run length in clusters.
* Doing it this way ensures that we signextend negative values.
* A negative run length doesn't make any sense, but hey, I
* didn't make up the NTFS specs and Windows NT4 treats the run
* length as a signed value so that's how it is...
*/
b = *buf & 0xf;
if ( b )
{
if ( buf + b > attr_end )
goto io_error;
for ( deltaxcn = ( s8 )buf[b--]; b; b-- )
deltaxcn = ( deltaxcn << 8 ) + buf[b];
}
else /* The length entry is compulsory. */
{
ntfs_log_debug( "Missing length entry in mapping pairs "
"array.\n" );
deltaxcn = ( s64 ) - 1;
}
/*
* Assume a negative length to indicate data corruption and
* hence clean-up and return NULL.
*/
if ( deltaxcn < 0 )
{
ntfs_log_debug( "Invalid length in mapping pairs array.\n" );
goto err_out;
}
/*
* Enter the current run length into the current runlist
* element.
*/
rl[rlpos].length = deltaxcn;
/* Increment the current vcn by the current run length. */
vcn += deltaxcn;
/*
* There might be no lcn change at all, as is the case for
* sparse clusters on NTFS 3.0+, in which case we set the lcn
* to LCN_HOLE.
*/
if ( !( *buf & 0xf0 ) )
rl[rlpos].lcn = ( LCN )LCN_HOLE;
else
{
/* Get the lcn change which really can be negative. */
u8 b2 = *buf & 0xf;
b = b2 + ( ( *buf >> 4 ) & 0xf );
if ( buf + b > attr_end )
goto io_error;
for ( deltaxcn = ( s8 )buf[b--]; b > b2; b-- )
deltaxcn = ( deltaxcn << 8 ) + buf[b];
/* Change the current lcn to it's new value. */
lcn += deltaxcn;
#ifdef DEBUG
/*
* On NTFS 1.2-, apparently can have lcn == -1 to
* indicate a hole. But we haven't verified ourselves
* whether it is really the lcn or the deltaxcn that is
* -1. So if either is found give us a message so we
* can investigate it further!
*/
if ( vol->major_ver < 3 )
{
if ( deltaxcn == ( LCN ) - 1 )
ntfs_log_debug( "lcn delta == -1\n" );
if ( lcn == ( LCN ) - 1 )
ntfs_log_debug( "lcn == -1\n" );
}
#endif
/* Check lcn is not below -1. */
if ( lcn < ( LCN ) - 1 )
{
ntfs_log_debug( "Invalid LCN < -1 in mapping pairs "
"array.\n" );
goto err_out;
}
/* Enter the current lcn into the runlist element. */
rl[rlpos].lcn = lcn;
}
/* Get to the next runlist element. */
rlpos++;
/* Increment the buffer position to the next mapping pair. */
buf += ( *buf & 0xf ) + ( ( *buf >> 4 ) & 0xf ) + 1;
}
if ( buf >= attr_end )
goto io_error;
/*
* If there is a highest_vcn specified, it must be equal to the final
* vcn in the runlist - 1, or something has gone badly wrong.
*/
deltaxcn = sle64_to_cpu( attr->highest_vcn );
if ( deltaxcn && vcn - 1 != deltaxcn )
{
mpa_err:
ntfs_log_debug( "Corrupt mapping pairs array in non-resident "
"attribute.\n" );
goto err_out;
}
/* Setup not mapped runlist element if this is the base extent. */
if ( !attr->lowest_vcn )
{
VCN max_cluster;
max_cluster = ( ( sle64_to_cpu( attr->allocated_size ) +
vol->cluster_size - 1 ) >>
vol->cluster_size_bits ) - 1;
/*
* A highest_vcn of zero means this is a single extent
* attribute so simply terminate the runlist with LCN_ENOENT).
*/
if ( deltaxcn )
{
/*
* If there is a difference between the highest_vcn and
* the highest cluster, the runlist is either corrupt
* or, more likely, there are more extents following
* this one.
*/
if ( deltaxcn < max_cluster )
{
ntfs_log_debug( "More extents to follow; deltaxcn = "
"0x%llx, max_cluster = 0x%llx\n",
( long long )deltaxcn,
( long long )max_cluster );
rl[rlpos].vcn = vcn;
vcn += rl[rlpos].length = max_cluster - deltaxcn;
rl[rlpos].lcn = ( LCN )LCN_RL_NOT_MAPPED;
rlpos++;
}
else if ( deltaxcn > max_cluster )
{
ntfs_log_debug( "Corrupt attribute. deltaxcn = "
"0x%llx, max_cluster = 0x%llx\n",
( long long )deltaxcn,
( long long )max_cluster );
goto mpa_err;
}
}
rl[rlpos].lcn = ( LCN )LCN_ENOENT;
}
else /* Not the base extent. There may be more extents to follow. */
rl[rlpos].lcn = ( LCN )LCN_RL_NOT_MAPPED;
/* Setup terminating runlist element. */
rl[rlpos].vcn = vcn;
rl[rlpos].length = ( s64 )0;
/* If no existing runlist was specified, we are done. */
if ( !old_rl )
{
ntfs_log_debug( "Mapping pairs array successfully decompressed:\n" );
ntfs_debug_runlist_dump( rl );
return rl;
}
/* Now combine the new and old runlists checking for overlaps. */
old_rl = ntfs_runlists_merge( old_rl, rl );
if ( old_rl )
return old_rl;
err = errno;
free( rl );
ntfs_log_debug( "Failed to merge runlists.\n" );
errno = err;
return NULL;
io_error:
ntfs_log_debug( "Corrupt attribute.\n" );
err_out:
free( rl );
errno = EIO;
return NULL;
}
runlist_element *ntfs_mapping_pairs_decompress( const ntfs_volume *vol,
const ATTR_RECORD *attr, runlist_element *old_rl )
{
runlist_element *rle;
ntfs_log_enter( "Entering\n" );
rle = ntfs_mapping_pairs_decompress_i( vol, attr, old_rl );
ntfs_log_leave( "\n" );
return rle;
}
/**
* ntfs_rl_vcn_to_lcn - convert a vcn into a lcn given a runlist
* @rl: runlist to use for conversion
* @vcn: vcn to convert
*
* Convert the virtual cluster number @vcn of an attribute into a logical
* cluster number (lcn) of a device using the runlist @rl to map vcns to their
* corresponding lcns.
*
* Since lcns must be >= 0, we use negative return values with special meaning:
*
* Return value Meaning / Description
* ==================================================
* -1 = LCN_HOLE Hole / not allocated on disk.
* -2 = LCN_RL_NOT_MAPPED This is part of the runlist which has not been
* inserted into the runlist yet.
* -3 = LCN_ENOENT There is no such vcn in the attribute.
* -4 = LCN_EINVAL Input parameter error.
*/
LCN ntfs_rl_vcn_to_lcn( const runlist_element *rl, const VCN vcn )
{
int i;
if ( vcn < ( VCN )0 )
return ( LCN )LCN_EINVAL;
/*
* If rl is NULL, assume that we have found an unmapped runlist. The
* caller can then attempt to map it and fail appropriately if
* necessary.
*/
if ( !rl )
return ( LCN )LCN_RL_NOT_MAPPED;
/* Catch out of lower bounds vcn. */
if ( vcn < rl[0].vcn )
return ( LCN )LCN_ENOENT;
for ( i = 0; rl[i].length; i++ )
{
if ( vcn < rl[i+1].vcn )
{
if ( rl[i].lcn >= ( LCN )0 )
return rl[i].lcn + ( vcn - rl[i].vcn );
return rl[i].lcn;
}
}
/*
* The terminator element is setup to the correct value, i.e. one of
* LCN_HOLE, LCN_RL_NOT_MAPPED, or LCN_ENOENT.
*/
if ( rl[i].lcn < ( LCN )0 )
return rl[i].lcn;
/* Just in case... We could replace this with BUG() some day. */
return ( LCN )LCN_ENOENT;
}
/**
* ntfs_rl_pread - gather read from disk
* @vol: ntfs volume to read from
* @rl: runlist specifying where to read the data from
* @pos: byte position within runlist @rl at which to begin the read
* @count: number of bytes to read
* @b: data buffer into which to read from disk
*
* This function will read @count bytes from the volume @vol to the data buffer
* @b gathering the data as specified by the runlist @rl. The read begins at
* offset @pos into the runlist @rl.
*
* 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
* 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.
*
* NOTE: If we encounter EOF while reading we return EIO because we assume that
* the run list must point to valid locations within the ntfs volume.
*/
s64 ntfs_rl_pread( const ntfs_volume *vol, const runlist_element *rl,
const s64 pos, s64 count, void *b )
{
s64 bytes_read, to_read, ofs, total;
int err = EIO;
if ( !vol || !rl || pos < 0 || count < 0 )
{
errno = EINVAL;
ntfs_log_perror( "Failed to read runlist [vol: %p rl: %p "
"pos: %lld count: %lld]", vol, rl,
( long long )pos, ( long long )count );
return -1;
}
if ( !count )
return count;
/* Seek in @rl to the run containing @pos. */
for ( ofs = 0; rl->length && ( ofs + ( rl->length <<
vol->cluster_size_bits ) <= pos ); rl++ )
ofs += ( rl->length << vol->cluster_size_bits );
/* Offset in the run at which to begin reading. */
ofs = pos - ofs;
for ( total = 0LL; count; rl++, ofs = 0 )
{
if ( !rl->length )
goto rl_err_out;
if ( rl->lcn < ( LCN )0 )
{
if ( rl->lcn != ( LCN )LCN_HOLE )
goto rl_err_out;
/* It is a hole. Just fill buffer @b with zeroes. */
to_read = min( count, ( rl->length <<
vol->cluster_size_bits ) - ofs );
memset( b, 0, to_read );
/* Update counters and proceed with next run. */
total += to_read;
count -= to_read;
b = ( u8* )b + to_read;
continue;
}
/* It is a real lcn, read it from the volume. */
to_read = min( count, ( rl->length << vol->cluster_size_bits ) -
ofs );
retry:
bytes_read = ntfs_pread( vol->dev, ( rl->lcn <<
vol->cluster_size_bits ) + ofs, to_read, b );
/* If everything ok, update progress counters and continue. */
if ( bytes_read > 0 )
{
total += bytes_read;
count -= bytes_read;
b = ( u8* )b + bytes_read;
continue;
}
/* If the syscall was interrupted, try again. */
if ( bytes_read == ( s64 ) - 1 && errno == EINTR )
goto retry;
if ( bytes_read == ( s64 ) - 1 )
err = errno;
goto rl_err_out;
}
/* Finally, return the number of bytes read. */
return total;
rl_err_out:
if ( total )
return total;
errno = err;
return -1;
}
/**
* ntfs_rl_pwrite - scatter write to disk
* @vol: ntfs volume to write to
* @rl: runlist entry specifying where to write the data to
* @ofs: offset in file for runlist element indicated in @rl
* @pos: byte position from runlist beginning at which to begin the write
* @count: number of bytes to write
* @b: data buffer to write to disk
*
* This function will write @count bytes from data buffer @b to the volume @vol
* scattering the data as specified by the runlist @rl. The write begins at
* offset @pos into the runlist @rl. If a run is sparse then the related buffer
* data is ignored which means that the caller must ensure they are consistent.
*
* On success, return the number of successfully written bytes. If this number
* is lower than @count this means that the write has been interrupted in
* flight or that an error was encountered during the write so that the write
* is partial. 0 means nothing was written (also return 0 when @count is 0).
*
* On error and nothing has been written, return -1 with errno set
* appropriately to the return code of ntfs_pwrite(), or to to EINVAL in case
* of invalid arguments.
*/
s64 ntfs_rl_pwrite( const ntfs_volume *vol, const runlist_element *rl,
s64 ofs, const s64 pos, s64 count, void *b )
{
s64 written, to_write, total = 0;
int err = EIO;
if ( !vol || !rl || pos < 0 || count < 0 )
{
errno = EINVAL;
ntfs_log_perror( "Failed to write runlist [vol: %p rl: %p "
"pos: %lld count: %lld]", vol, rl,
( long long )pos, ( long long )count );
goto errno_set;
}
if ( !count )
goto out;
/* Seek in @rl to the run containing @pos. */
while ( rl->length && ( ofs + ( rl->length <<
vol->cluster_size_bits ) <= pos ) )
{
ofs += ( rl->length << vol->cluster_size_bits );
rl++;
}
/* Offset in the run at which to begin writing. */
ofs = pos - ofs;
for ( total = 0LL; count; rl++, ofs = 0 )
{
if ( !rl->length )
goto rl_err_out;
if ( rl->lcn < ( LCN )0 )
{
if ( rl->lcn != ( LCN )LCN_HOLE )
goto rl_err_out;
to_write = min( count, ( rl->length <<
vol->cluster_size_bits ) - ofs );
total += to_write;
count -= to_write;
b = ( u8* )b + to_write;
continue;
}
/* It is a real lcn, write it to the volume. */
to_write = min( count, ( rl->length << vol->cluster_size_bits ) -
ofs );
retry:
if ( !NVolReadOnly( vol ) )
written = ntfs_pwrite( vol->dev, ( rl->lcn <<
vol->cluster_size_bits ) + ofs,
to_write, b );
else
written = to_write;
/* If everything ok, update progress counters and continue. */
if ( written > 0 )
{
total += written;
count -= written;
b = ( u8* )b + written;
continue;
}
/* If the syscall was interrupted, try again. */
if ( written == ( s64 ) - 1 && errno == EINTR )
goto retry;
if ( written == ( s64 ) - 1 )
err = errno;
goto rl_err_out;
}
out:
return total;
rl_err_out:
if ( total )
goto out;
errno = err;
errno_set:
total = -1;
goto out;
}
/**
* ntfs_get_nr_significant_bytes - get number of bytes needed to store a number
* @n: number for which to get the number of bytes for
*
* Return the number of bytes required to store @n unambiguously as
* a signed number.
*
* This is used in the context of the mapping pairs array to determine how
* many bytes will be needed in the array to store a given logical cluster
* number (lcn) or a specific run length.
*
* Return the number of bytes written. This function cannot fail.
*/
int ntfs_get_nr_significant_bytes( const s64 n )
{
u64 l;
int i;
l = ( n < 0 ? ~n : n );
i = 1;
if ( l >= 128 )
{
l >>= 7;
do
{
i++;
l >>= 8;
}
while ( l );
}
return i;
}
/**
* ntfs_get_size_for_mapping_pairs - get bytes needed for mapping pairs array
* @vol: ntfs volume (needed for the ntfs version)
* @rl: runlist for which to determine the size of the mapping pairs
* @start_vcn: vcn at which to start the mapping pairs array
*
* Walk the runlist @rl and calculate the size in bytes of the mapping pairs
* array corresponding to the runlist @rl, starting at vcn @start_vcn. This
* for example allows us to allocate a buffer of the right size when building
* the mapping pairs array.
*
* If @rl is NULL, just return 1 (for the single terminator byte).
*
* Return the calculated size in bytes on success. On error, return -1 with
* errno set to the error code. The following error codes are defined:
* EINVAL - Run list contains unmapped elements. Make sure to only pass
* fully mapped runlists to this function.
* - @start_vcn is invalid.
* EIO - The runlist is corrupt.
*/
int ntfs_get_size_for_mapping_pairs( const ntfs_volume *vol,
const runlist_element *rl, const VCN start_vcn, int max_size )
{
LCN prev_lcn;
int rls;
if ( start_vcn < 0 )
{
ntfs_log_trace( "start_vcn %lld (should be >= 0)\n",
( long long ) start_vcn );
errno = EINVAL;
goto errno_set;
}
if ( !rl )
{
if ( start_vcn )
{
ntfs_log_trace( "rl NULL, start_vcn %lld (should be > 0)\n",
( long long ) start_vcn );
errno = EINVAL;
goto errno_set;
}
rls = 1;
goto out;
}
/* Skip to runlist element containing @start_vcn. */
while ( rl->length && start_vcn >= rl[1].vcn )
rl++;
if ( ( !rl->length && start_vcn > rl->vcn ) || start_vcn < rl->vcn )
{
errno = EINVAL;
goto errno_set;
}
prev_lcn = 0;
/* Always need the terminating zero byte. */
rls = 1;
/* Do the first partial run if present. */
if ( start_vcn > rl->vcn )
{
s64 delta;
/* We know rl->length != 0 already. */
if ( rl->length < 0 || rl->lcn < LCN_HOLE )
goto err_out;
delta = start_vcn - rl->vcn;
/* Header byte + length. */
rls += 1 + ntfs_get_nr_significant_bytes( rl->length - delta );
/*
* If the logical cluster number (lcn) denotes a hole and we
* are on NTFS 3.0+, we don't store it at all, i.e. we need
* zero space. On earlier NTFS versions we just store the lcn.
* Note: this assumes that on NTFS 1.2-, holes are stored with
* an lcn of -1 and not a delta_lcn of -1 (unless both are -1).
*/
if ( rl->lcn >= 0 || vol->major_ver < 3 )
{
prev_lcn = rl->lcn;
if ( rl->lcn >= 0 )
prev_lcn += delta;
/* Change in lcn. */
rls += ntfs_get_nr_significant_bytes( prev_lcn );
}
/* Go to next runlist element. */
rl++;
}
/* Do the full runs. */
for ( ; rl->length && ( rls <= max_size ); rl++ )
{
if ( rl->length < 0 || rl->lcn < LCN_HOLE )
goto err_out;
/* Header byte + length. */
rls += 1 + ntfs_get_nr_significant_bytes( rl->length );
/*
* If the logical cluster number (lcn) denotes a hole and we
* are on NTFS 3.0+, we don't store it at all, i.e. we need
* zero space. On earlier NTFS versions we just store the lcn.
* Note: this assumes that on NTFS 1.2-, holes are stored with
* an lcn of -1 and not a delta_lcn of -1 (unless both are -1).
*/
if ( rl->lcn >= 0 || vol->major_ver < 3 )
{
/* Change in lcn. */
rls += ntfs_get_nr_significant_bytes( rl->lcn -
prev_lcn );
prev_lcn = rl->lcn;
}
}
out:
return rls;
err_out:
if ( rl->lcn == LCN_RL_NOT_MAPPED )
errno = EINVAL;
else
errno = EIO;
errno_set:
rls = -1;
goto out;
}
/**
* ntfs_write_significant_bytes - write the significant bytes of a number
* @dst: destination buffer to write to
* @dst_max: pointer to last byte of destination buffer for bounds checking
* @n: number whose significant bytes to write
*
* Store in @dst, the minimum bytes of the number @n which are required to
* identify @n unambiguously as a signed number, taking care not to exceed
* @dest_max, the maximum position within @dst to which we are allowed to
* write.
*
* This is used when building the mapping pairs array of a runlist to compress
* a given logical cluster number (lcn) or a specific run length to the minimum
* size possible.
*
* Return the number of bytes written on success. On error, i.e. the
* destination buffer @dst is too small, return -1 with errno set ENOSPC.
*/
int ntfs_write_significant_bytes( u8 *dst, const u8 *dst_max, const s64 n )
{
s64 l = n;
int i;
s8 j;
i = 0;
do
{
if ( dst > dst_max )
goto err_out;
*dst++ = l & 0xffLL;
l >>= 8;
i++;
}
while ( l != 0LL && l != -1LL );
j = ( n >> 8 * ( i - 1 ) ) & 0xff;
/* If the sign bit is wrong, we need an extra byte. */
if ( n < 0LL && j >= 0 )
{
if ( dst > dst_max )
goto err_out;
i++;
*dst = ( u8 ) - 1;
}
else if ( n > 0LL && j < 0 )
{
if ( dst > dst_max )
goto err_out;
i++;
*dst = 0;
}
return i;
err_out:
errno = ENOSPC;
return -1;
}
/**
* ntfs_mapping_pairs_build - build the mapping pairs array from a runlist
* @vol: ntfs volume (needed for the ntfs version)
* @dst: destination buffer to which to write the mapping pairs array
* @dst_len: size of destination buffer @dst in bytes
* @rl: runlist for which to build the mapping pairs array
* @start_vcn: vcn at which to start the mapping pairs array
* @stop_vcn: first vcn outside destination buffer on success or ENOSPC error
*
* Create the mapping pairs array from the runlist @rl, starting at vcn
* @start_vcn and save the array in @dst. @dst_len is the size of @dst in
* bytes and it should be at least equal to the value obtained by calling
* ntfs_get_size_for_mapping_pairs().
*
* If @rl is NULL, just write a single terminator byte to @dst.
*
* On success or ENOSPC error, if @stop_vcn is not NULL, *@stop_vcn is set to
* the first vcn outside the destination buffer. Note that on error @dst has
* been filled with all the mapping pairs that will fit, thus it can be treated
* as partial success, in that a new attribute extent needs to be created or the
* next extent has to be used and the mapping pairs build has to be continued
* with @start_vcn set to *@stop_vcn.
*
* Return 0 on success. On error, return -1 with errno set to the error code.
* The following error codes are defined:
* EINVAL - Run list contains unmapped elements. Make sure to only pass
* fully mapped runlists to this function.
* - @start_vcn is invalid.
* EIO - The runlist is corrupt.
* ENOSPC - The destination buffer is too small.
*/
int ntfs_mapping_pairs_build( const ntfs_volume *vol, u8 *dst,
const int dst_len, const runlist_element *rl,
const VCN start_vcn, runlist_element const **stop_rl )
{
LCN prev_lcn;
u8 *dst_max, *dst_next;
s8 len_len, lcn_len;
int ret = 0;
if ( start_vcn < 0 )
goto val_err;
if ( !rl )
{
if ( start_vcn )
goto val_err;
if ( stop_rl )
*stop_rl = rl;
if ( dst_len < 1 )
goto nospc_err;
goto ok;
}
/* Skip to runlist element containing @start_vcn. */
while ( rl->length && start_vcn >= rl[1].vcn )
rl++;
if ( ( !rl->length && start_vcn > rl->vcn ) || start_vcn < rl->vcn )
goto val_err;
/*
* @dst_max is used for bounds checking in
* ntfs_write_significant_bytes().
*/
dst_max = dst + dst_len - 1;
prev_lcn = 0;
/* Do the first partial run if present. */
if ( start_vcn > rl->vcn )
{
s64 delta;
/* We know rl->length != 0 already. */
if ( rl->length < 0 || rl->lcn < LCN_HOLE )
goto err_out;
delta = start_vcn - rl->vcn;
/* Write length. */
len_len = ntfs_write_significant_bytes( dst + 1, dst_max,
rl->length - delta );
if ( len_len < 0 )
goto size_err;
/*
* If the logical cluster number (lcn) denotes a hole and we
* are on NTFS 3.0+, we don't store it at all, i.e. we need
* zero space. On earlier NTFS versions we just write the lcn
* change. FIXME: Do we need to write the lcn change or just
* the lcn in that case? Not sure as I have never seen this
* case on NT4. - We assume that we just need to write the lcn
* change until someone tells us otherwise... (AIA)
*/
if ( rl->lcn >= 0 || vol->major_ver < 3 )
{
prev_lcn = rl->lcn;
if ( rl->lcn >= 0 )
prev_lcn += delta;
/* Write change in lcn. */
lcn_len = ntfs_write_significant_bytes( dst + 1 +
len_len, dst_max, prev_lcn );
if ( lcn_len < 0 )
goto size_err;
}
else
lcn_len = 0;
dst_next = dst + len_len + lcn_len + 1;
if ( dst_next > dst_max )
goto size_err;
/* Update header byte. */
*dst = lcn_len << 4 | len_len;
/* Position at next mapping pairs array element. */
dst = dst_next;
/* Go to next runlist element. */
rl++;
}
/* Do the full runs. */
for ( ; rl->length; rl++ )
{
if ( rl->length < 0 || rl->lcn < LCN_HOLE )
goto err_out;
/* Write length. */
len_len = ntfs_write_significant_bytes( dst + 1, dst_max,
rl->length );
if ( len_len < 0 )
goto size_err;
/*
* If the logical cluster number (lcn) denotes a hole and we
* are on NTFS 3.0+, we don't store it at all, i.e. we need
* zero space. On earlier NTFS versions we just write the lcn
* change. FIXME: Do we need to write the lcn change or just
* the lcn in that case? Not sure as I have never seen this
* case on NT4. - We assume that we just need to write the lcn
* change until someone tells us otherwise... (AIA)
*/
if ( rl->lcn >= 0 || vol->major_ver < 3 )
{
/* Write change in lcn. */
lcn_len = ntfs_write_significant_bytes( dst + 1 +
len_len, dst_max, rl->lcn - prev_lcn );
if ( lcn_len < 0 )
goto size_err;
prev_lcn = rl->lcn;
}
else
lcn_len = 0;
dst_next = dst + len_len + lcn_len + 1;
if ( dst_next > dst_max )
goto size_err;
/* Update header byte. */
*dst = lcn_len << 4 | len_len;
/* Position at next mapping pairs array element. */
dst += 1 + len_len + lcn_len;
}
/* Set stop vcn. */
if ( stop_rl )
*stop_rl = rl;
ok:
/* Add terminator byte. */
*dst = 0;
out:
return ret;
size_err:
/* Set stop vcn. */
if ( stop_rl )
*stop_rl = rl;
/* Add terminator byte. */
*dst = 0;
nospc_err:
errno = ENOSPC;
goto errno_set;
val_err:
errno = EINVAL;
goto errno_set;
err_out:
if ( rl->lcn == LCN_RL_NOT_MAPPED )
errno = EINVAL;
else
errno = EIO;
errno_set:
ret = -1;
goto out;
}
/**
* ntfs_rl_truncate - truncate a runlist starting at a specified vcn
* @arl: address of runlist to truncate
* @start_vcn: first vcn which should be cut off
*
* Truncate the runlist *@arl starting at vcn @start_vcn as well as the memory
* buffer holding the runlist.
*
* Return 0 on success and -1 on error with errno set to the error code.
*
* NOTE: @arl is the address of the runlist. We need the address so we can
* modify the pointer to the runlist with the new, reallocated memory buffer.
*/
int ntfs_rl_truncate( runlist **arl, const VCN start_vcn )
{
runlist *rl;
BOOL is_end = FALSE;
if ( !arl || !*arl )
{
errno = EINVAL;
if ( !arl )
ntfs_log_perror( "rl_truncate error: arl: %p", arl );
else
ntfs_log_perror( "rl_truncate error:"
" arl: %p *arl: %p", arl, *arl );
return -1;
}
rl = *arl;
if ( start_vcn < rl->vcn )
{
errno = EINVAL;
ntfs_log_perror( "Start_vcn lies outside front of runlist" );
return -1;
}
/* Find the starting vcn in the run list. */
while ( rl->length )
{
if ( start_vcn < rl[1].vcn )
break;
rl++;
}
if ( !rl->length )
{
errno = EIO;
ntfs_log_trace( "Truncating already truncated runlist?\n" );
return -1;
}
/* Truncate the run. */
rl->length = start_vcn - rl->vcn;
/*
* If a run was partially truncated, make the following runlist
* element a terminator instead of the truncated runlist
* element itself.
*/
if ( rl->length )
{
++rl;
if ( !rl->length )
is_end = TRUE;
rl->vcn = start_vcn;
rl->length = 0;
}
rl->lcn = ( LCN )LCN_ENOENT;
/**
* Reallocate memory if necessary.
* FIXME: Below code is broken, because runlist allocations must be
* a multiply of 4096. The code caused crashes and corruptions.
*/
/*
if (!is_end) {
size_t new_size = (rl - *arl + 1) * sizeof(runlist_element);
rl = realloc(*arl, new_size);
if (rl)
*arl = rl;
}
*/
return 0;
}
/**
* ntfs_rl_sparse - check whether runlist have sparse regions or not.
* @rl: runlist to check
*
* Return 1 if have, 0 if not, -1 on error with errno set to the error code.
*/
int ntfs_rl_sparse( runlist *rl )
{
runlist *rlc;
if ( !rl )
{
errno = EINVAL;
ntfs_log_perror( "%s: ", __FUNCTION__ );
return -1;
}
for ( rlc = rl; rlc->length; rlc++ )
if ( rlc->lcn < 0 )
{
if ( rlc->lcn != LCN_HOLE )
{
errno = EINVAL;
ntfs_log_perror( "%s: bad runlist", __FUNCTION__ );
return -1;
}
return 1;
}
return 0;
}
/**
* ntfs_rl_get_compressed_size - calculate length of non sparse regions
* @vol: ntfs volume (need for cluster size)
* @rl: runlist to calculate for
*
* Return compressed size or -1 on error with errno set to the error code.
*/
s64 ntfs_rl_get_compressed_size( ntfs_volume *vol, runlist *rl )
{
runlist *rlc;
s64 ret = 0;
if ( !rl )
{
errno = EINVAL;
ntfs_log_perror( "%s: ", __FUNCTION__ );
return -1;
}
for ( rlc = rl; rlc->length; rlc++ )
{
if ( rlc->lcn < 0 )
{
if ( rlc->lcn != LCN_HOLE )
{
errno = EINVAL;
ntfs_log_perror( "%s: bad runlist", __FUNCTION__ );
return -1;
}
}
else
ret += rlc->length;
}
return ret << vol->cluster_size_bits;
}
#ifdef NTFS_TEST
/**
* test_rl_helper
*/
#define MKRL(R,V,L,S) \
(R)->vcn = V; \
(R)->lcn = L; \
(R)->length = S;
/*
}
*/
/**
* test_rl_dump_runlist - Runlist test: Display the contents of a runlist
* @rl:
*
* Description...
*
* Returns:
*/
static void test_rl_dump_runlist( const runlist_element *rl )
{
int abbr = 0; /* abbreviate long lists */
int len = 0;
int i;
const char *lcn_str[5] = { "HOLE", "NOTMAP", "ENOENT", "XXXX" };
if ( !rl )
{
printf( " Run list not present.\n" );
return;
}
if ( abbr )
for ( len = 0; rl[len].length; len++ ) ;
printf( " VCN LCN len\n" );
for ( i = 0; ; i++, rl++ )
{
LCN lcn = rl->lcn;
if ( ( abbr ) && ( len > 20 ) )
{
if ( i == 4 )
printf( " ...\n" );
if ( ( i > 3 ) && ( i < ( len - 3 ) ) )
continue;
}
if ( lcn < ( LCN )0 )
{
int ind = -lcn - 1;
if ( ind > -LCN_ENOENT - 1 )
ind = 3;
printf( "%8lld %8s %8lld\n",
rl->vcn, lcn_str[ind], rl->length );
}
else
printf( "%8lld %8lld %8lld\n",
rl->vcn, rl->lcn, rl->length );
if ( !rl->length )
break;
}
if ( ( abbr ) && ( len > 20 ) )
printf( " (%d entries)\n", len + 1 );
printf( "\n" );
}
/**
* test_rl_runlists_merge - Runlist test: Merge two runlists
* @drl:
* @srl:
*
* Description...
*
* Returns:
*/
static runlist_element * test_rl_runlists_merge( runlist_element *drl, runlist_element *srl )
{
runlist_element *res = NULL;
printf( "dst:\n" );
test_rl_dump_runlist( drl );
printf( "src:\n" );
test_rl_dump_runlist( srl );
res = ntfs_runlists_merge( drl, srl );
printf( "res:\n" );
test_rl_dump_runlist( res );
return res;
}
/**
* test_rl_read_buffer - Runlist test: Read a file containing a runlist
* @file:
* @buf:
* @bufsize:
*
* Description...
*
* Returns:
*/
static int test_rl_read_buffer( const char *file, u8 *buf, int bufsize )
{
FILE *fptr;
fptr = fopen( file, "r" );
if ( !fptr )
{
printf( "open %s\n", file );
return 0;
}
if ( fread( buf, bufsize, 1, fptr ) == 99 )
{
printf( "read %s\n", file );
return 0;
}
fclose( fptr );
return 1;
}
/**
* test_rl_pure_src - Runlist test: Complicate the simple tests a little
* @contig:
* @multi:
* @vcn:
* @len:
*
* Description...
*
* Returns:
*/
static runlist_element * test_rl_pure_src( BOOL contig, BOOL multi, int vcn, int len )
{
runlist_element *result;
int fudge;
if ( contig )
fudge = 0;
else
fudge = 999;
result = ntfs_malloc( 4096 );
if ( !result )
return NULL;
if ( multi )
{
MKRL( result + 0, vcn + ( 0*len / 4 ), fudge + vcn + 1000 + ( 0*len / 4 ), len / 4 )
MKRL( result + 1, vcn + ( 1*len / 4 ), fudge + vcn + 1000 + ( 1*len / 4 ), len / 4 )
MKRL( result + 2, vcn + ( 2*len / 4 ), fudge + vcn + 1000 + ( 2*len / 4 ), len / 4 )
MKRL( result + 3, vcn + ( 3*len / 4 ), fudge + vcn + 1000 + ( 3*len / 4 ), len / 4 )
MKRL( result + 4, vcn + ( 4*len / 4 ), LCN_RL_NOT_MAPPED, 0 )
}
else
{
MKRL( result + 0, vcn, fudge + vcn + 1000, len )
MKRL( result + 1, vcn + len, LCN_RL_NOT_MAPPED, 0 )
}
return result;
}
/**
* test_rl_pure_test - Runlist test: Perform tests using simple runlists
* @test:
* @contig:
* @multi:
* @vcn:
* @len:
* @file:
* @size:
*
* Description...
*
* Returns:
*/
static void test_rl_pure_test( int test, BOOL contig, BOOL multi, int vcn, int len, runlist_element *file, int size )
{
runlist_element *src;
runlist_element *dst;
runlist_element *res;
src = test_rl_pure_src( contig, multi, vcn, len );
dst = ntfs_malloc( 4096 );
if ( !src || !dst )
{
printf( "Test %2d ---------- FAILED! (no free memory?)\n", test );
return;
}
memcpy( dst, file, size );
printf( "Test %2d ----------\n", test );
res = test_rl_runlists_merge( dst, src );
free( res );
}
/**
* test_rl_pure - Runlist test: Create tests using simple runlists
* @contig:
* @multi:
*
* Description...
*
* Returns:
*/
static void test_rl_pure( char *contig, char *multi )
{
/* VCN, LCN, len */
static runlist_element file1[] =
{
{ 0, -1, 100 }, /* HOLE */
{ 100, 1100, 100 }, /* DATA */
{ 200, -1, 100 }, /* HOLE */
{ 300, 1300, 100 }, /* DATA */
{ 400, -1, 100 }, /* HOLE */
{ 500, -3, 0 } /* NOENT */
};
static runlist_element file2[] =
{
{ 0, 1000, 100 }, /* DATA */
{ 100, -1, 100 }, /* HOLE */
{ 200, -3, 0 } /* NOENT */
};
static runlist_element file3[] =
{
{ 0, 1000, 100 }, /* DATA */
{ 100, -3, 0 } /* NOENT */
};
static runlist_element file4[] =
{
{ 0, -3, 0 } /* NOENT */
};
static runlist_element file5[] =
{
{ 0, -2, 100 }, /* NOTMAP */
{ 100, 1100, 100 }, /* DATA */
{ 200, -2, 100 }, /* NOTMAP */
{ 300, 1300, 100 }, /* DATA */
{ 400, -2, 100 }, /* NOTMAP */
{ 500, -3, 0 } /* NOENT */
};
static runlist_element file6[] =
{
{ 0, 1000, 100 }, /* DATA */
{ 100, -2, 100 }, /* NOTMAP */
{ 200, -3, 0 } /* NOENT */
};
BOOL c, m;
if ( strcmp( contig, "contig" ) == 0 )
c = TRUE;
else if ( strcmp( contig, "noncontig" ) == 0 )
c = FALSE;
else
{
printf( "rl pure [contig|noncontig] [single|multi]\n" );
return;
}
if ( strcmp( multi, "multi" ) == 0 )
m = TRUE;
else if ( strcmp( multi, "single" ) == 0 )
m = FALSE;
else
{
printf( "rl pure [contig|noncontig] [single|multi]\n" );
return;
}
test_rl_pure_test( 1, c, m, 0, 40, file1, sizeof( file1 ) );
test_rl_pure_test( 2, c, m, 40, 40, file1, sizeof( file1 ) );
test_rl_pure_test( 3, c, m, 60, 40, file1, sizeof( file1 ) );
test_rl_pure_test( 4, c, m, 0, 100, file1, sizeof( file1 ) );
test_rl_pure_test( 5, c, m, 200, 40, file1, sizeof( file1 ) );
test_rl_pure_test( 6, c, m, 240, 40, file1, sizeof( file1 ) );
test_rl_pure_test( 7, c, m, 260, 40, file1, sizeof( file1 ) );
test_rl_pure_test( 8, c, m, 200, 100, file1, sizeof( file1 ) );
test_rl_pure_test( 9, c, m, 400, 40, file1, sizeof( file1 ) );
test_rl_pure_test( 10, c, m, 440, 40, file1, sizeof( file1 ) );
test_rl_pure_test( 11, c, m, 460, 40, file1, sizeof( file1 ) );
test_rl_pure_test( 12, c, m, 400, 100, file1, sizeof( file1 ) );
test_rl_pure_test( 13, c, m, 160, 100, file2, sizeof( file2 ) );
test_rl_pure_test( 14, c, m, 100, 140, file2, sizeof( file2 ) );
test_rl_pure_test( 15, c, m, 200, 40, file2, sizeof( file2 ) );
test_rl_pure_test( 16, c, m, 240, 40, file2, sizeof( file2 ) );
test_rl_pure_test( 17, c, m, 100, 40, file3, sizeof( file3 ) );
test_rl_pure_test( 18, c, m, 140, 40, file3, sizeof( file3 ) );
test_rl_pure_test( 19, c, m, 0, 40, file4, sizeof( file4 ) );
test_rl_pure_test( 20, c, m, 40, 40, file4, sizeof( file4 ) );
test_rl_pure_test( 21, c, m, 0, 40, file5, sizeof( file5 ) );
test_rl_pure_test( 22, c, m, 40, 40, file5, sizeof( file5 ) );
test_rl_pure_test( 23, c, m, 60, 40, file5, sizeof( file5 ) );
test_rl_pure_test( 24, c, m, 0, 100, file5, sizeof( file5 ) );
test_rl_pure_test( 25, c, m, 200, 40, file5, sizeof( file5 ) );
test_rl_pure_test( 26, c, m, 240, 40, file5, sizeof( file5 ) );
test_rl_pure_test( 27, c, m, 260, 40, file5, sizeof( file5 ) );
test_rl_pure_test( 28, c, m, 200, 100, file5, sizeof( file5 ) );
test_rl_pure_test( 29, c, m, 400, 40, file5, sizeof( file5 ) );
test_rl_pure_test( 30, c, m, 440, 40, file5, sizeof( file5 ) );
test_rl_pure_test( 31, c, m, 460, 40, file5, sizeof( file5 ) );
test_rl_pure_test( 32, c, m, 400, 100, file5, sizeof( file5 ) );
test_rl_pure_test( 33, c, m, 160, 100, file6, sizeof( file6 ) );
test_rl_pure_test( 34, c, m, 100, 140, file6, sizeof( file6 ) );
}
/**
* test_rl_zero - Runlist test: Merge a zero-length runlist
*
* Description...
*
* Returns:
*/
static void test_rl_zero( void )
{
runlist_element *jim = NULL;
runlist_element *bob = NULL;
bob = calloc( 3, sizeof( runlist_element ) );
if ( !bob )
return;
MKRL( bob + 0, 10, 99, 5 )
MKRL( bob + 1, 15, LCN_RL_NOT_MAPPED, 0 )
jim = test_rl_runlists_merge( jim, bob );
if ( !jim )
return;
free( jim );
}
/**
* test_rl_frag_combine - Runlist test: Perform tests using fragmented files
* @vol:
* @attr1:
* @attr2:
* @attr3:
*
* Description...
*
* Returns:
*/
static void test_rl_frag_combine( ntfs_volume *vol, ATTR_RECORD *attr1, ATTR_RECORD *attr2, ATTR_RECORD *attr3 )
{
runlist_element *run1;
runlist_element *run2;
runlist_element *run3;
run1 = ntfs_mapping_pairs_decompress( vol, attr1, NULL );
if ( !run1 )
return;
run2 = ntfs_mapping_pairs_decompress( vol, attr2, NULL );
if ( !run2 )
return;
run1 = test_rl_runlists_merge( run1, run2 );
run3 = ntfs_mapping_pairs_decompress( vol, attr3, NULL );
if ( !run3 )
return;
run1 = test_rl_runlists_merge( run1, run3 );
free( run1 );
}
/**
* test_rl_frag - Runlist test: Create tests using very fragmented files
* @test:
*
* Description...
*
* Returns:
*/
static void test_rl_frag( char *test )
{
ntfs_volume vol;
ATTR_RECORD *attr1 = ntfs_malloc( 1024 );
ATTR_RECORD *attr2 = ntfs_malloc( 1024 );
ATTR_RECORD *attr3 = ntfs_malloc( 1024 );
if ( !attr1 || !attr2 || !attr3 )
goto out;
vol.sb = NULL;
vol.sector_size_bits = 9;
vol.cluster_size = 2048;
vol.cluster_size_bits = 11;
vol.major_ver = 3;
if ( !test_rl_read_buffer( "runlist-data/attr1.bin", ( u8* ) attr1, 1024 ) )
goto out;
if ( !test_rl_read_buffer( "runlist-data/attr2.bin", ( u8* ) attr2, 1024 ) )
goto out;
if ( !test_rl_read_buffer( "runlist-data/attr3.bin", ( u8* ) attr3, 1024 ) )
goto out;
if ( strcmp( test, "123" ) == 0 ) test_rl_frag_combine( &vol, attr1, attr2, attr3 );
else if ( strcmp( test, "132" ) == 0 ) test_rl_frag_combine( &vol, attr1, attr3, attr2 );
else if ( strcmp( test, "213" ) == 0 ) test_rl_frag_combine( &vol, attr2, attr1, attr3 );
else if ( strcmp( test, "231" ) == 0 ) test_rl_frag_combine( &vol, attr2, attr3, attr1 );
else if ( strcmp( test, "312" ) == 0 ) test_rl_frag_combine( &vol, attr3, attr1, attr2 );
else if ( strcmp( test, "321" ) == 0 ) test_rl_frag_combine( &vol, attr3, attr2, attr1 );
else
printf( "Frag: No such test '%s'\n", test );
out:
free( attr1 );
free( attr2 );
free( attr3 );
}
/**
* test_rl_main - Runlist test: Program start (main)
* @argc:
* @argv:
*
* Description...
*
* Returns:
*/
int test_rl_main( int argc, char *argv[] )
{
if ( ( argc == 2 ) && ( strcmp( argv[1], "zero" ) == 0 ) ) test_rl_zero();
else if ( ( argc == 3 ) && ( strcmp( argv[1], "frag" ) == 0 ) ) test_rl_frag( argv[2] );
else if ( ( argc == 4 ) && ( strcmp( argv[1], "pure" ) == 0 ) ) test_rl_pure( argv[2], argv[3] );
else
printf( "rl [zero|frag|pure] {args}\n" );
return 0;
}
#endif
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