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transmission/libtransmission/inout.c

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/******************************************************************************
* $Id$
*
* Copyright (c) 2005-2006 Transmission authors and contributors
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*****************************************************************************/
#include "transmission.h"
struct tr_io_s
{
tr_torrent_t * tor;
/* Position of pieces
-1 = we haven't started to download this piece yet
n = we have started or completed the piece in slot n */
int * pieceSlot;
/* Pieces in slot
-1 = unused slot
n = piece n */
int * slotPiece;
int slotsUsed;
};
#include "fastresume.h"
/***********************************************************************
* Local prototypes
**********************************************************************/
static int checkFiles( tr_io_t * );
static void closeFiles( tr_io_t * );
static int readOrWriteBytes( tr_io_t *, uint64_t, int, uint8_t *, int );
static int readOrWriteSlot( tr_io_t * io, int slot, uint8_t * buf,
int * size, int write );
static void findSlotForPiece( tr_io_t *, int );
#define readBytes(io,o,s,b) readOrWriteBytes(io,o,s,b,0)
#define writeBytes(io,o,s,b) readOrWriteBytes(io,o,s,b,1)
#define readSlot(io,sl,b,s) readOrWriteSlot(io,sl,b,s,0)
#define writeSlot(io,sl,b,s) readOrWriteSlot(io,sl,b,s,1)
/***********************************************************************
* tr_ioLoadResume
***********************************************************************
* Try to load the fast resume file
**********************************************************************/
void tr_ioLoadResume( tr_torrent_t * tor )
{
tr_io_t * io;
tr_info_t * inf = &tor->info;
io = malloc( sizeof( tr_io_t ) );
io->tor = tor;
io->pieceSlot = malloc( inf->pieceCount * sizeof( int ) );
io->slotPiece = malloc( inf->pieceCount * sizeof( int ) );
fastResumeLoad( io );
free( io->pieceSlot );
free( io->slotPiece );
free( io );
}
/***********************************************************************
* tr_ioInit
***********************************************************************
* Open all files we are going to write to
**********************************************************************/
tr_io_t * tr_ioInit( tr_torrent_t * tor )
{
tr_io_t * io;
io = malloc( sizeof( tr_io_t ) );
io->tor = tor;
if( checkFiles( io ) )
{
free( io );
return NULL;
}
return io;
}
/***********************************************************************
* tr_ioRead
**********************************************************************/
int tr_ioRead( tr_io_t * io, int index, int begin, int length,
uint8_t * buf )
{
tr_info_t * inf = &io->tor->info;
uint64_t offset;
offset = (uint64_t) io->pieceSlot[index] *
(uint64_t) inf->pieceSize + (uint64_t) begin;
return readBytes( io, offset, length, buf );
}
/***********************************************************************
* tr_ioWrite
**********************************************************************/
int tr_ioWrite( tr_io_t * io, int index, int begin, int length,
uint8_t * buf )
{
tr_info_t * inf = &io->tor->info;
uint64_t offset;
if( io->pieceSlot[index] < 0 )
{
findSlotForPiece( io, index );
tr_inf( "Piece %d: starting in slot %d", index,
io->pieceSlot[index] );
}
offset = (uint64_t) io->pieceSlot[index] *
(uint64_t) inf->pieceSize + (uint64_t) begin;
return writeBytes( io, offset, length, buf );
}
/***********************************************************************
* tr_ioHash
**********************************************************************/
int tr_ioHash( tr_io_t * io, int index )
{
tr_torrent_t * tor = io->tor;
tr_info_t * inf = &io->tor->info;
int pieceSize;
uint8_t * pieceBuf;
uint8_t hash[SHA_DIGEST_LENGTH];
int hashFailed;
int ret;
int i;
pieceSize = tr_pieceSize( index );
pieceBuf = malloc( pieceSize );
if( ( ret = readBytes( io, (uint64_t) io->pieceSlot[index] *
(uint64_t) inf->pieceSize, pieceSize, pieceBuf ) ) )
{
free( pieceBuf );
return ret;
}
SHA1( pieceBuf, pieceSize, hash );
free( pieceBuf );
hashFailed = memcmp( hash, &inf->pieces[20*index], SHA_DIGEST_LENGTH );
if( hashFailed )
{
tr_inf( "Piece %d (slot %d): hash FAILED", index,
io->pieceSlot[index] );
tr_cpPieceRem( tor->completion, index );
}
else
{
tr_inf( "Piece %d (slot %d): hash OK", index,
io->pieceSlot[index] );
tr_cpPieceAdd( tor->completion, index );
}
/* Assign blame or credit to peers */
for( i = 0; i < tor->peerCount; i++ )
{
tr_peerBlame( tor->peers[i], index, !hashFailed );
}
return 0;
}
/***********************************************************************
* tr_ioSync
**********************************************************************/
void tr_ioSync( tr_io_t * io )
{
closeFiles( io );
fastResumeSave( io );
}
/***********************************************************************
* tr_ioClose
**********************************************************************/
void tr_ioClose( tr_io_t * io )
{
tr_ioSync( io );
free( io->pieceSlot );
free( io->slotPiece );
free( io );
}
/***********************************************************************
* checkFiles
***********************************************************************
* Look for pieces
**********************************************************************/
static int checkFiles( tr_io_t * io )
{
tr_torrent_t * tor = io->tor;
tr_info_t * inf = &tor->info;
int i;
uint8_t * buf;
uint8_t hash[SHA_DIGEST_LENGTH];
struct stat sb;
io->pieceSlot = malloc( inf->pieceCount * sizeof( int ) );
io->slotPiece = malloc( inf->pieceCount * sizeof( int ) );
if( !fastResumeLoad( io ) )
{
return 0;
}
tr_dbg( "Checking pieces..." );
/* Yet we don't have anything */
memset( io->pieceSlot, 0xFF, inf->pieceCount * sizeof( int ) );
memset( io->slotPiece, 0xFF, inf->pieceCount * sizeof( int ) );
/* Truncate files that are too large */
for( i = 0; inf->fileCount > i; i++ )
{
if( 0 > stat( inf->files[i].name, &sb ) )
{
if( ENOENT == errno )
{
continue;
}
tr_err( "Could not stat %s (%s)",
inf->files[i].name, strerror( errno ) );
break;
}
if( sb.st_size > ( off_t )inf->files[i].length )
{
tr_dbg( "truncate %s from %"PRIu64" to %"PRIu64" bytes",
inf->files[i].name, sb.st_size, inf->files[i].length );
truncate( inf->files[i].name, inf->files[i].length );
}
}
/* Check pieces */
io->slotsUsed = 0;
buf = malloc( inf->pieceSize );
for( i = 0; i < inf->pieceCount; i++ )
{
int size, j;
if( readSlot( io, i, buf, &size ) )
{
break;
}
io->slotsUsed = i + 1;
SHA1( buf, size, hash );
for( j = i; j < inf->pieceCount - 1; j++ )
{
if( !memcmp( hash, &inf->pieces[20*j], SHA_DIGEST_LENGTH ) )
{
io->pieceSlot[j] = i;
io->slotPiece[i] = j;
tr_cpPieceAdd( tor->completion, j );
break;
}
}
if( io->slotPiece[i] > -1 )
{
continue;
}
/* Special case for the last piece */
SHA1( buf, tr_pieceSize( inf->pieceCount - 1 ), hash );
if( !memcmp( hash, &inf->pieces[20 * (inf->pieceCount - 1)],
SHA_DIGEST_LENGTH ) )
{
io->pieceSlot[inf->pieceCount - 1] = i;
io->slotPiece[i] = inf->pieceCount - 1;
tr_cpPieceAdd( tor->completion, inf->pieceCount - 1 );
}
}
free( buf );
return 0;
}
/***********************************************************************
* closeFiles
**********************************************************************/
static void closeFiles( tr_io_t * io )
{
tr_torrent_t * tor = io->tor;
tr_info_t * inf = &tor->info;
int i;
for( i = 0; i < inf->fileCount; i++ )
{
tr_fdFileClose( tor->destination, inf->files[i].name );
}
}
/***********************************************************************
* readOrWriteBytes
***********************************************************************
*
**********************************************************************/
typedef size_t (* iofunc) ( int, void *, size_t );
static int readOrWriteBytes( tr_io_t * io, uint64_t offset, int size,
uint8_t * buf, int isWrite )
{
tr_torrent_t * tor = io->tor;
tr_info_t * inf = &tor->info;
int piece = offset / inf->pieceSize;
int begin = offset % inf->pieceSize;
int i;
size_t cur;
int file;
iofunc readOrWrite = isWrite ? (iofunc) write : (iofunc) read;
int ret = 0;
/* Release the torrent lock so the UI can still update itself if
this blocks for a while */
tr_lockUnlock( &tor->lock );
/* We don't ever read or write more than a piece at a time */
if( tr_pieceSize( piece ) < begin + size )
{
tr_err( "readOrWriteBytes: trying to write more than a piece" );
ret = TR_ERROR_ASSERT;
goto cleanup;
}
/* Find which file we shall start reading/writing in */
for( i = 0; i < inf->fileCount; i++ )
{
if( offset < inf->files[i].length )
{
/* This is the file */
break;
}
offset -= inf->files[i].length;
}
if( i >= inf->fileCount )
{
/* Should not happen */
tr_err( "readOrWriteBytes: offset out of range (%"PRIu64", %d, %d)",
offset, size, isWrite );
ret = TR_ERROR_ASSERT;
goto cleanup;
}
while( size > 0 )
{
/* How much can we put or take with this file */
if( inf->files[i].length < offset + size )
{
cur = (int) ( inf->files[i].length - offset );
}
else
{
cur = size;
}
if( cur > 0 )
{
/* Now let's get a descriptor on the file... */
file = tr_fdFileOpen( tor->destination, inf->files[i].name,
isWrite );
if( file < 0 )
{
ret = file;
goto cleanup;
}
/* seek to the right offset... */
if( lseek( file, offset, SEEK_SET ) < 0 )
{
tr_fdFileRelease( file );
ret = TR_ERROR_IO_OTHER;
goto cleanup;
}
/* do what we are here to do... */
if( readOrWrite( file, buf, cur ) != cur )
{
tr_fdFileRelease( file );
ret = TR_ERROR_IO_OTHER;
goto cleanup;
}
/* and release the descriptor. */
tr_fdFileRelease( file );
}
/* 'cur' bytes done, 'size - cur' bytes to go with the next file */
i += 1;
offset = 0;
size -= cur;
buf += cur;
}
cleanup:
tr_lockLock( &tor->lock );
return ret;
}
/***********************************************************************
* readSlot
***********************************************************************
*
**********************************************************************/
static int readOrWriteSlot( tr_io_t * io, int slot, uint8_t * buf,
int * size, int write )
{
tr_torrent_t * tor = io->tor;
tr_info_t * inf = &tor->info;
uint64_t offset = (uint64_t) slot * (uint64_t) inf->pieceSize;
*size = 0;
if( slot == inf->pieceCount - 1 )
{
*size = inf->totalSize % inf->pieceSize;
}
if( !*size )
{
*size = inf->pieceSize;
}
return readOrWriteBytes( io, offset, *size, buf, write );
}
static void invertSlots( tr_io_t * io, int slot1, int slot2 )
{
tr_torrent_t * tor = io->tor;
tr_info_t * inf = &tor->info;
uint8_t * buf1, * buf2;
int piece1, piece2, foo;
buf1 = calloc( inf->pieceSize, 1 );
buf2 = calloc( inf->pieceSize, 1 );
readSlot( io, slot1, buf1, &foo );
readSlot( io, slot2, buf2, &foo );
writeSlot( io, slot1, buf2, &foo );
writeSlot( io, slot2, buf1, &foo );
free( buf1 );
free( buf2 );
piece1 = io->slotPiece[slot1];
piece2 = io->slotPiece[slot2];
io->slotPiece[slot1] = piece2;
io->slotPiece[slot2] = piece1;
if( piece1 >= 0 )
{
io->pieceSlot[piece1] = slot2;
}
if( piece2 >= 0 )
{
io->pieceSlot[piece2] = slot1;
}
}
static void reorderPieces( tr_io_t * io )
{
tr_torrent_t * tor = io->tor;
tr_info_t * inf = &tor->info;
int i, didInvert;
/* Try to move pieces to their final places */
do
{
didInvert = 0;
for( i = 0; i < inf->pieceCount; i++ )
{
if( io->pieceSlot[i] < 0 )
{
/* We haven't started this piece yet */
continue;
}
if( io->pieceSlot[i] == i )
{
/* Already in place */
continue;
}
if( i >= io->slotsUsed )
{
/* File is not big enough yet */
continue;
}
/* Move piece i into slot i */
tr_inf( "invert %d and %d", io->pieceSlot[i], i );
invertSlots( io, i, io->pieceSlot[i] );
didInvert = 1;
}
} while( didInvert );
}
static void findSlotForPiece( tr_io_t * io, int piece )
{
int i;
#if 0
tr_torrent_t * tor = io->tor;
tr_info_t * inf = &tor->info;
tr_dbg( "Entering findSlotForPiece" );
for( i = 0; i < inf->pieceCount; i++ )
printf( "%02d ", io->slotPiece[i] );
printf( "\n" );
for( i = 0; i < inf->pieceCount; i++ )
printf( "%02d ", io->pieceSlot[i] );
printf( "\n" );
#endif
/* Look for an empty slot somewhere */
for( i = 0; i < io->slotsUsed; i++ )
{
if( io->slotPiece[i] < 0 )
{
io->pieceSlot[piece] = i;
io->slotPiece[i] = piece;
goto reorder;
}
}
/* No empty slot, extend the file */
io->pieceSlot[piece] = io->slotsUsed;
io->slotPiece[io->slotsUsed] = piece;
(io->slotsUsed)++;
reorder:
reorderPieces( io );
#if 0
for( i = 0; i < inf->pieceCount; i++ )
printf( "%02d ", io->slotPiece[i] );
printf( "\n" );
for( i = 0; i < inf->pieceCount; i++ )
printf( "%02d ", io->pieceSlot[i] );
printf( "\n" );
printf( "Leaving findSlotForPiece\n" );
#endif
}
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