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transmission/libtransmission/inout.c

329 lines
8.4 KiB
C

/*
* This file Copyright (C) 2007 Charles Kerr <charles@rebelbase.com>
*
* This file is licensed by the GPL version 2. Works owned by the
* Transmission project are granted a special exemption to clause 2(b)
* so that the bulk of its code can remain under the MIT license.
* This exemption does not extend to derived works not owned by
* the Transmission project.
*/
#include "transmission.h"
#include "fastresume.h"
#include "fdlimit.h"
struct tr_io_s
{
tr_torrent_t * tor;
};
/****
***** Low-level IO functions
****/
enum { TR_IO_READ, TR_IO_WRITE };
static int
readOrWriteBytes ( const tr_torrent_t * tor,
int ioMode,
int fileIndex,
uint64_t fileOffset,
void * buf,
size_t buflen )
{
const tr_info_t * info = &tor->info;
const tr_file_t * file = &info->files[fileIndex];
int fd, ret;
typedef size_t (* iofunc) ( int, void *, size_t );
iofunc func = ioMode == TR_IO_READ ? (iofunc)read : (iofunc)write;
assert ( 0<=fileIndex && fileIndex<info->fileCount );
assert ( !file->length || (fileOffset < file->length));
assert ( fileOffset + buflen <= file->length );
if( !file->length )
return 0;
else if ((fd = tr_fdFileOpen ( tor->destination, file->name, ioMode==TR_IO_WRITE )) < 0)
ret = fd;
else if( lseek( fd, (off_t)fileOffset, SEEK_SET ) == ((off_t)-1) )
ret = TR_ERROR_IO_OTHER;
else if( func( fd, buf, buflen ) != buflen )
ret = tr_ioErrorFromErrno ();
else
ret = TR_OK;
if( fd >= 0 )
tr_fdFileRelease( fd );
return ret;
}
static void
findFileLocation ( const tr_torrent_t * tor,
int pieceIndex,
int pieceOffset,
int * fileIndex,
uint64_t * fileOffset )
{
const tr_info_t * info = &tor->info;
int i;
uint64_t piecePos = ((uint64_t)pieceIndex * info->pieceSize) + pieceOffset;
assert ( 0<=pieceIndex && pieceIndex < info->pieceCount );
assert ( 0<=tor->info.pieceSize );
assert ( pieceOffset < tr_pieceSize(pieceIndex) );
assert ( piecePos < info->totalSize );
for ( i=0; info->files[i].length<=piecePos; ++i )
piecePos -= info->files[i].length;
*fileIndex = i;
*fileOffset = piecePos;
assert ( 0<=*fileIndex && *fileIndex<info->fileCount );
assert ( *fileOffset < info->files[i].length );
}
static int
ensureMinimumFileSize ( const tr_torrent_t * tor,
int fileIndex,
uint64_t minSize ) /* in bytes */
{
int fd;
int ret;
struct stat sb;
const tr_file_t * file = &tor->info.files[fileIndex];
assert ( 0<=fileIndex && fileIndex<tor->info.fileCount );
assert ( minSize <= file->length );
fd = tr_fdFileOpen( tor->destination, file->name, TRUE );
if( fd < 0 ) /* bad fd */
ret = fd;
else if (fstat (fd, &sb) ) /* how big is the file? */
ret = tr_ioErrorFromErrno ();
else if ((size_t)sb.st_size >= minSize) /* already big enough */
ret = TR_OK;
else if (!ftruncate( fd, minSize )) /* grow it */
ret = TR_OK;
else /* couldn't grow it */
ret = tr_ioErrorFromErrno ();
if( fd >= 0 )
tr_fdFileRelease( fd );
return ret;
}
static int
readOrWritePiece ( tr_torrent_t * tor,
int ioMode,
int pieceIndex,
int pieceOffset,
uint8_t * buf,
size_t buflen )
{
int ret = 0;
int fileIndex;
uint64_t fileOffset;
const tr_info_t * info = &tor->info;
assert( 0<=pieceIndex && pieceIndex<tor->info.pieceCount );
assert( buflen <= (size_t) tr_pieceSize( pieceIndex ) );
findFileLocation ( tor, pieceIndex, pieceOffset, &fileIndex, &fileOffset );
while( buflen && !ret )
{
const tr_file_t * file = &info->files[fileIndex];
const uint64_t bytesThisPass = MIN( buflen, file->length - fileOffset );
if( ioMode == TR_IO_WRITE )
ret = ensureMinimumFileSize( tor, fileIndex,
fileOffset + bytesThisPass );
if( !ret )
ret = readOrWriteBytes( tor, ioMode,
fileIndex, fileOffset, buf, bytesThisPass );
buf += bytesThisPass;
buflen -= bytesThisPass;
fileIndex++;
fileOffset = 0;
}
return ret;
}
int
tr_ioRead( tr_io_t * io, int pieceIndex, int begin, int len, uint8_t * buf )
{
return readOrWritePiece ( io->tor, TR_IO_READ, pieceIndex, begin, buf, len );
}
int
tr_ioWrite( tr_io_t * io, int pieceIndex, int begin, int len, uint8_t * buf )
{
return readOrWritePiece ( io->tor, TR_IO_WRITE, pieceIndex, begin, buf, len );
}
/****
*****
****/
static int
tr_ioRecalculateHash ( tr_torrent_t * tor,
int pieceIndex,
uint8_t * setme )
{
int n;
int ret;
uint8_t * buf;
const tr_info_t * info;
assert( tor != NULL );
assert( setme != NULL );
assert( 0<=pieceIndex && pieceIndex<tor->info.pieceCount );
info = &tor->info;
n = tr_pieceSize( pieceIndex );
buf = malloc( n );
ret = readOrWritePiece ( tor, TR_IO_READ, pieceIndex, 0, buf, n );
if( !ret ) {
SHA1( buf, n, setme );
}
free( buf );
return ret;
}
static int
checkPiece ( tr_torrent_t * tor, int pieceIndex )
{
uint8_t hash[SHA_DIGEST_LENGTH];
int ret = tr_ioRecalculateHash( tor, pieceIndex, hash )
|| memcmp( hash, tor->info.pieces[pieceIndex].hash, SHA_DIGEST_LENGTH );
tr_dbg ("torrent [%s] piece %d hash check: %s",
tor->info.name, pieceIndex, (ret?"FAILED":"OK"));
return ret;
}
int
tr_ioCheckFiles( tr_torrent_t * tor, int mode )
{
int i;
tr_bitfield_t * uncheckedPieces = tr_bitfieldNew( tor->info.pieceCount );
tr_cpReset( tor->completion );
tr_bitfieldClear( uncheckedPieces );
if( (mode==TR_RECHECK_FORCE) || fastResumeLoad( tor, uncheckedPieces ) )
tr_bitfieldAddRange( uncheckedPieces, 0, tor->info.pieceCount-1 );
if( tr_bitfieldIsEmpty( uncheckedPieces ) ) {
tr_bitfieldFree( uncheckedPieces );
return TR_OK;
}
if( mode == TR_RECHECK_FAST ) {
tr_bitfieldFree( uncheckedPieces );
return TR_ERROR_IO_OTHER;
}
tr_inf( "Verifying some pieces of \"%s\"", tor->info.name );
for( i=0; i<tor->info.pieceCount; ++i )
{
if( !tr_bitfieldHas( uncheckedPieces, i ) )
continue;
tr_dbg ( "Checking piece %d because it's not in fast-resume", i );
tr_torrentSetHasPiece( tor, i, !checkPiece( tor, i ) );
tr_bitfieldRem( uncheckedPieces, i );
}
fastResumeSave( tor );
tr_bitfieldFree( uncheckedPieces );
return TR_OK;
}
/****
***** Life Cycle
****/
tr_io_t*
tr_ioInitFast( tr_torrent_t * tor )
{
tr_io_t * io = tr_calloc( 1, sizeof( tr_io_t ) );
io->tor = tor;
if( tr_ioCheckFiles( tor, TR_RECHECK_FAST ) )
{
tr_free( io );
io = NULL;
}
return io;
}
void
tr_ioSync( tr_io_t * io )
{
if( io != NULL )
{
int i;
const tr_info_t * info = &io->tor->info;
for( i=0; i<info->fileCount; ++i )
tr_fdFileClose( io->tor->destination, info->files[i].name );
fastResumeSave( io->tor );
}
}
void
tr_ioClose( tr_io_t * io )
{
if( io != NULL )
{
tr_ioSync( io );
tr_free( io );
}
}
/* try to load the fast resume file */
int
tr_ioLoadResume( tr_torrent_t * tor )
{
return tr_ioCheckFiles ( tor, TR_RECHECK_FAST );
}
int
tr_ioHash( tr_io_t * io, int pieceIndex )
{
int i;
tr_torrent_t * tor = io->tor;
const int success = !checkPiece( tor, pieceIndex );
if( success )
{
tr_inf( "Piece %d hash OK", pieceIndex );
tr_cpPieceAdd( tor->completion, pieceIndex );
}
else
{
tr_err( "Piece %d hash FAILED", pieceIndex );
tr_cpPieceRem( tor->completion, pieceIndex );
}
/* Assign blame or credit to peers */
for( i = 0; i < tor->peerCount; ++i )
tr_peerBlame( tor->peers[i], pieceIndex, success );
return 0;
}