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transmission/libtransmission/metainfo.c

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/******************************************************************************
* $Id$
*
* Copyright (c) 2005-2007 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 <sys/types.h>
#include <sys/stat.h>
#include <unistd.h> /* unlink, stat */
#include "transmission.h"
#include "bencode.h"
#include "http.h" /* tr_httpParseUrl */
#include "metainfo.h"
#define TORRENT_MAX_SIZE (5*1024*1024)
/***********************************************************************
* Local prototypes
**********************************************************************/
static int realparse( tr_info_t * inf, const uint8_t * buf, size_t len );
static void savedname( char * name, size_t len, const char * hash,
const char * tag );
static uint8_t * readtorrent( const char * path, size_t * len );
static int savetorrent( const char * hash, const char * tag,
const uint8_t * buf, size_t buflen );
static int getfile( char * buf, int size,
const char * prefix, benc_val_t * name );
static int getannounce( tr_info_t * inf, benc_val_t * meta );
static char * announceToScrape( const char * announce );
static int parseFiles( tr_info_t * inf, benc_val_t * name,
benc_val_t * files, benc_val_t * length );
static void strcatUTF8( char *, int, const char *, int );
/***********************************************************************
* tr_metainfoParse
***********************************************************************
*
**********************************************************************/
int
tr_metainfoParseFile( tr_info_t * inf, const char * tag,
const char * path, int save )
{
uint8_t * buf;
size_t size;
/* read the torrent data */
buf = readtorrent( path, &size );
if( NULL == buf )
{
return TR_EINVALID;
}
if( realparse( inf, buf, size ) )
{
free( buf );
return TR_EINVALID;
}
if( save )
{
if( savetorrent( inf->hashString, tag, buf, size ) )
{
free( buf );
return TR_EINVALID;
}
savedname( inf->torrent, sizeof inf->torrent, inf->hashString, tag );
}
else
{
snprintf( inf->torrent, sizeof inf->torrent, "%s", path );
}
free( buf );
return TR_OK;
}
int
tr_metainfoParseData( tr_info_t * inf, const char * tag,
const uint8_t * data, size_t size, int save )
{
if( realparse( inf, data, size ) )
{
return TR_EINVALID;
}
if( save )
{
if( savetorrent( inf->hashString, tag, data, size ) )
{
return TR_EINVALID;
}
savedname( inf->torrent, sizeof inf->torrent, inf->hashString, tag );
}
return TR_OK;
}
int
tr_metainfoParseHash( tr_info_t * inf, const char * tag, const char * hash )
{
struct stat sb;
uint8_t * buf;
size_t size;
int save;
/* check it we should use an old file without a tag */
/* XXX this should go away at some point */
save = 0;
savedname( inf->torrent, sizeof inf->torrent, hash, tag );
if( 0 > stat( inf->torrent, &sb ) && ENOENT == errno )
{
savedname( inf->torrent, sizeof inf->torrent, hash, NULL );
if( 0 == stat( inf->torrent, &sb ))
{
save = 1;
}
}
buf = readtorrent( inf->torrent, &size );
if( NULL == buf )
{
return TR_EINVALID;
}
if( realparse( inf, buf, size ) )
{
free( buf );
return TR_EINVALID;
}
/* save a new tagged copy of the old untagged torrent */
if( save )
{
if( savetorrent( hash, tag, buf, size ) )
{
free( buf );
return TR_EINVALID;
}
savedname( inf->torrent, sizeof inf->torrent, hash, tag );
}
free( buf );
return TR_OK;
}
static int
realparse( tr_info_t * inf, const uint8_t * buf, size_t size )
{
benc_val_t meta, * beInfo, * val, * val2;
int i;
/* Parse bencoded infos */
if( tr_bencLoad( buf, size, &meta, NULL ) )
{
tr_err( "Error while parsing bencoded data [%*.*s]", (int)size, (int)size, (char*)buf );
return TR_EINVALID;
}
/* Get info hash */
beInfo = tr_bencDictFind( &meta, "info" );
if( NULL == beInfo || TYPE_DICT != beInfo->type )
{
tr_err( "%s \"info\" dictionary", ( beInfo ? "Invalid" : "Missing" ) );
tr_bencFree( &meta );
return TR_EINVALID;
}
SHA1( (uint8_t *) beInfo->begin,
(long) beInfo->end - (long) beInfo->begin, inf->hash );
for( i = 0; i < SHA_DIGEST_LENGTH; i++ )
{
snprintf( inf->hashString + i * 2, sizeof( inf->hashString ) - i * 2,
"%02x", inf->hash[i] );
}
/* Comment info */
val = tr_bencDictFindFirst( &meta, "comment.utf-8", "comment", NULL );
if( NULL != val && TYPE_STR == val->type )
{
strcatUTF8( inf->comment, sizeof( inf->comment ), val->val.s.s, 0 );
}
/* Creator info */
val = tr_bencDictFindFirst( &meta, "created by.utf-8", "created by", NULL );
if( NULL != val && TYPE_STR == val->type )
{
strcatUTF8( inf->creator, sizeof( inf->creator ), val->val.s.s, 0 );
}
/* Date created */
inf->dateCreated = 0;
val = tr_bencDictFind( &meta, "creation date" );
if( NULL != val && TYPE_INT == val->type )
{
inf->dateCreated = val->val.i;
}
/* Private torrent */
val = tr_bencDictFind( beInfo, "private" );
val2 = tr_bencDictFind( &meta, "private" );
if( ( NULL != val && ( TYPE_INT != val->type || 0 != val->val.i ) ) ||
( NULL != val2 && ( TYPE_INT != val2->type || 0 != val2->val.i ) ) )
{
inf->flags |= TR_FLAG_PRIVATE;
}
/* Piece length */
val = tr_bencDictFind( beInfo, "piece length" );
if( NULL == val || TYPE_INT != val->type )
{
tr_err( "%s \"piece length\" entry", ( val ? "Invalid" : "Missing" ) );
goto fail;
}
inf->pieceSize = val->val.i;
/* Hashes */
val = tr_bencDictFind( beInfo, "pieces" );
if( NULL == val || TYPE_STR != val->type )
{
tr_err( "%s \"pieces\" entry", ( val ? "Invalid" : "Missing" ) );
goto fail;
}
if( val->val.s.i % SHA_DIGEST_LENGTH )
{
tr_err( "Invalid \"piece\" string (size is %d)", val->val.s.i );
goto fail;
}
inf->pieceCount = val->val.s.i / SHA_DIGEST_LENGTH;
inf->pieces = calloc ( inf->pieceCount, sizeof(tr_piece_t) );
for ( i=0; i<inf->pieceCount; ++i )
{
memcpy (inf->pieces[i].hash, &val->val.s.s[i*SHA_DIGEST_LENGTH], SHA_DIGEST_LENGTH);
}
/* get file or top directory name */
val = tr_bencDictFindFirst( beInfo, "name.utf-8", "name", NULL );
if( parseFiles( inf, tr_bencDictFindFirst( beInfo,
"name.utf-8", "name", NULL ),
tr_bencDictFind( beInfo, "files" ),
tr_bencDictFind( beInfo, "length" ) ) )
{
goto fail;
}
if( !inf->fileCount )
{
tr_err( "Torrent has no files." );
goto fail;
}
if( !inf->totalSize )
{
tr_err( "Torrent is zero bytes long." );
goto fail;
}
/* TODO add more tests so we don't crash on weird files */
if( (uint64_t) inf->pieceCount !=
( inf->totalSize + inf->pieceSize - 1 ) / inf->pieceSize )
{
tr_err( "Size of hashes and files don't match" );
goto fail;
}
/* get announce or announce-list */
if( getannounce( inf, &meta ) )
{
goto fail;
}
tr_bencFree( &meta );
return TR_OK;
fail:
tr_metainfoFree( inf );
tr_bencFree( &meta );
return TR_EINVALID;
}
void tr_metainfoFree( tr_info_t * inf )
{
int ii, jj;
tr_free( inf->pieces );
tr_free( inf->files );
for( ii = 0; ii < inf->trackerTiers; ii++ )
{
for( jj = 0; jj < inf->trackerList[ii].count; jj++ )
{
tr_free( inf->trackerList[ii].list[jj].address );
tr_free( inf->trackerList[ii].list[jj].announce );
tr_free( inf->trackerList[ii].list[jj].scrape );
}
tr_free( inf->trackerList[ii].list );
}
tr_free( inf->trackerList );
memset( inf, '\0', sizeof(tr_info_t) );
}
static int getfile( char * buf, int size,
const char * prefix, benc_val_t * name )
{
benc_val_t * dir;
const char ** list;
int ii, jj;
if( TYPE_LIST != name->type )
{
return TR_EINVALID;
}
list = calloc( name->val.l.count, sizeof( list[0] ) );
if( NULL == list )
{
return TR_EINVALID;
}
for( ii = jj = 0; name->val.l.count > ii; ii++ )
{
dir = &name->val.l.vals[ii];
if( TYPE_STR != dir->type )
{
continue;
}
if( 0 == strcmp( "..", dir->val.s.s ) )
{
if( 0 < jj )
{
jj--;
}
}
else if( 0 != strcmp( ".", dir->val.s.s ) )
{
list[jj] = dir->val.s.s;
jj++;
}
}
if( 0 == jj )
{
free( list );
return TR_EINVALID;
}
strcatUTF8( buf, size, prefix, 0 );
for( ii = 0; jj > ii; ii++ )
{
strcatUTF8( buf, size, TR_PATH_DELIMITER_STR, 0 );
strcatUTF8( buf, size, list[ii], 1 );
}
free( list );
return TR_OK;
}
static int getannounce( tr_info_t * inf, benc_val_t * meta )
{
benc_val_t * val, * subval, * urlval;
char * address, * announce;
int ii, jj, port, random, subcount;
tr_tracker_info_t * sublist;
void * swapping;
/* Announce-list */
val = tr_bencDictFind( meta, "announce-list" );
if( NULL != val && TYPE_LIST == val->type && 0 < val->val.l.count )
{
inf->trackerTiers = 0;
inf->trackerList = calloc( val->val.l.count,
sizeof( inf->trackerList[0] ) );
/* iterate through the announce-list's tiers */
for( ii = 0; ii < val->val.l.count; ii++ )
{
subval = &val->val.l.vals[ii];
if( TYPE_LIST != subval->type || 0 >= subval->val.l.count )
{
continue;
}
subcount = 0;
sublist = calloc( subval->val.l.count, sizeof( sublist[0] ) );
/* iterate through the tier's items */
for( jj = 0; jj < subval->val.l.count; jj++ )
{
urlval = &subval->val.l.vals[jj];
if( TYPE_STR != urlval->type ||
tr_httpParseUrl( urlval->val.s.s, urlval->val.s.i,
&address, &port, &announce ) )
{
continue;
}
/* place the item info in a random location in the sublist */
random = tr_rand( subcount + 1 );
if( random != subcount )
{
sublist[subcount] = sublist[random];
}
sublist[random].address = address;
sublist[random].port = port;
sublist[random].announce = announce;
sublist[random].scrape = announceToScrape( announce );
subcount++;
}
/* just use sublist as-is if it's full */
if( subcount == subval->val.l.count )
{
inf->trackerList[inf->trackerTiers].list = sublist;
inf->trackerList[inf->trackerTiers].count = subcount;
inf->trackerTiers++;
}
/* if we skipped some of the tier's items then trim the sublist */
else if( 0 < subcount )
{
inf->trackerList[inf->trackerTiers].list = calloc( subcount, sizeof( sublist[0] ) );
memcpy( inf->trackerList[inf->trackerTiers].list, sublist,
sizeof( sublist[0] ) * subcount );
inf->trackerList[inf->trackerTiers].count = subcount;
inf->trackerTiers++;
free( sublist );
}
/* drop the whole sublist if we didn't use any items at all */
else
{
free( sublist );
}
}
/* did we use any of the tiers? */
if( 0 == inf->trackerTiers )
{
tr_inf( "No valid entries in \"announce-list\"" );
free( inf->trackerList );
inf->trackerList = NULL;
}
/* trim unused sublist pointers */
else if( inf->trackerTiers < val->val.l.count )
{
swapping = inf->trackerList;
inf->trackerList = calloc( inf->trackerTiers,
sizeof( inf->trackerList[0] ) );
memcpy( inf->trackerList, swapping,
sizeof( inf->trackerList[0] ) * inf->trackerTiers );
free( swapping );
}
}
/* Regular announce value */
if( 0 == inf->trackerTiers )
{
val = tr_bencDictFind( meta, "announce" );
if( NULL == val || TYPE_STR != val->type )
{
tr_err( "No \"announce\" entry" );
return TR_EINVALID;
}
if( tr_httpParseUrl( val->val.s.s, val->val.s.i,
&address, &port, &announce ) )
{
tr_err( "Invalid announce URL (%s)", val->val.s.s );
return TR_EINVALID;
}
sublist = calloc( 1, sizeof( sublist[0] ) );
sublist[0].address = address;
sublist[0].port = port;
sublist[0].announce = announce;
sublist[0].scrape = announceToScrape( announce );
inf->trackerList = calloc( 1, sizeof( inf->trackerList[0] ) );
inf->trackerList[0].list = sublist;
inf->trackerList[0].count = 1;
inf->trackerTiers = 1;
}
return TR_OK;
}
static char * announceToScrape( const char * announce )
{
char old[] = "announce";
int oldlen = 8;
char new[] = "scrape";
int newlen = 6;
char * slash, * scrape;
size_t scrapelen, used;
slash = strrchr( announce, '/' );
if( NULL == slash )
{
return NULL;
}
slash++;
if( 0 != strncmp( slash, old, oldlen ) )
{
return NULL;
}
scrapelen = strlen( announce ) - oldlen + newlen;
scrape = calloc( scrapelen + 1, 1 );
if( NULL == scrape )
{
return NULL;
}
assert( ( size_t )( slash - announce ) < scrapelen );
memcpy( scrape, announce, slash - announce );
used = slash - announce;
strncat( scrape, new, scrapelen - used );
used += newlen;
assert( strlen( scrape ) == used );
if( used < scrapelen )
{
assert( strlen( slash + oldlen ) == scrapelen - used );
strncat( scrape, slash + oldlen, scrapelen - used );
}
return scrape;
}
static void
savedname( char * name, size_t len, const char * hash, const char * tag )
{
const char * torDir = tr_getTorrentsDirectory ();
if( tag == NULL )
{
tr_buildPath( name, len, torDir, hash, NULL );
}
else
{
char base[1024];
snprintf( base, sizeof(base), "%s-%s", hash, tag );
tr_buildPath( name, len, torDir, base, NULL );
}
}
void tr_metainfoRemoveSaved( const char * hashString, const char * tag )
{
char file[MAX_PATH_LENGTH];
savedname( file, sizeof file, hashString, tag );
unlink( file );
}
static uint8_t *
readtorrent( const char * path, size_t * size )
{
uint8_t * buf;
struct stat sb;
FILE * file;
/* try to stat the file */
errno = 0;
if( stat( path, &sb ) )
{
tr_err( "Couldn't get information for file \"%s\" %s", path, strerror(errno) );
return NULL;
}
if( ( sb.st_mode & S_IFMT ) != S_IFREG )
{
tr_err( "Not a regular file (%s)", path );
return NULL;
}
if( sb.st_size > TORRENT_MAX_SIZE )
{
tr_err( "Torrent file is too big (%"PRIu64" bytes)",
( uint64_t )sb.st_size );
return NULL;
}
/* Load the torrent file into our buffer */
file = fopen( path, "rb" );
if( !file )
{
tr_err( "Couldn't open file \"%s\" %s", path, strerror(errno) );
return NULL;
}
buf = malloc( sb.st_size );
if( NULL == buf )
{
tr_err( "Couldn't allocate memory (%"PRIu64" bytes)",
( uint64_t )sb.st_size );
}
fseek( file, 0, SEEK_SET );
if( fread( buf, sb.st_size, 1, file ) != 1 )
{
tr_err( "Error reading \"%s\" %s", path, strerror(errno) );
free( buf );
fclose( file );
return NULL;
}
fclose( file );
*size = sb.st_size;
return buf;
}
/* Save a copy of the torrent file in the saved torrent directory */
static int
savetorrent( const char * hash, const char * tag,
const uint8_t * buf, size_t buflen )
{
char path[MAX_PATH_LENGTH];
FILE * file;
savedname( path, sizeof path, hash, tag );
file = fopen( path, "wb" );
if( !file )
{
tr_err( "Could not open file (%s) (%s)", path, strerror( errno ) );
return TR_EINVALID;
}
fseek( file, 0, SEEK_SET );
if( fwrite( buf, 1, buflen, file ) != buflen )
{
tr_err( "Could not write file (%s) (%s)", path, strerror( errno ) );
fclose( file );
return TR_EINVALID;
}
fclose( file );
return TR_OK;
}
static int
parseFiles( tr_info_t * inf, benc_val_t * name,
benc_val_t * files, benc_val_t * length )
{
benc_val_t * item, * path;
int ii;
if( NULL == name || TYPE_STR != name->type )
{
tr_err( "%s \"name\" string", ( name ? "Invalid" : "Missing" ) );
return TR_EINVALID;
}
strcatUTF8( inf->name, sizeof( inf->name ), name->val.s.s, 1 );
if( '\0' == inf->name[0] )
{
tr_err( "Invalid \"name\" string" );
return TR_EINVALID;
}
inf->totalSize = 0;
if( files && TYPE_LIST == files->type )
{
/* Multi-file mode */
inf->multifile = 1;
inf->fileCount = files->val.l.count;
inf->files = calloc( inf->fileCount, sizeof( inf->files[0] ) );
if( NULL == inf->files )
{
return TR_EINVALID;
}
for( ii = 0; files->val.l.count > ii; ii++ )
{
item = &files->val.l.vals[ii];
path = tr_bencDictFindFirst( item, "path.utf-8", "path", NULL );
if( getfile( inf->files[ii].name, sizeof( inf->files[0].name ),
inf->name, path ) )
{
tr_err( "%s \"path\" entry",
( path ? "Invalid" : "Missing" ) );
return TR_EINVALID;
}
length = tr_bencDictFind( item, "length" );
if( NULL == length || TYPE_INT != length->type )
{
tr_err( "%s \"length\" entry",
( length ? "Invalid" : "Missing" ) );
return TR_EINVALID;
}
inf->files[ii].length = length->val.i;
inf->totalSize += length->val.i;
}
}
else if( NULL != length && TYPE_INT == length->type )
{
/* Single-file mode */
inf->multifile = 0;
inf->fileCount = 1;
inf->files = calloc( 1, sizeof( inf->files[0] ) );
if( NULL == inf->files )
{
return TR_EINVALID;
}
strcatUTF8( inf->files[0].name, sizeof( inf->files[0].name ),
name->val.s.s, 1 );
inf->files[0].length = length->val.i;
inf->totalSize += length->val.i;
}
else
{
tr_err( "%s \"files\" entry and %s \"length\" entry",
( files ? "Invalid" : "Missing" ),
( length ? "invalid" : "missing" ) );
}
return TR_OK;
}
/***********************************************************************
* strcatUTF8
***********************************************************************
* According to the official specification, all strings in the torrent
* file are supposed to be UTF-8 encoded. However, there are
* non-compliant torrents around... If we encounter an invalid UTF-8
* character, we assume it is ISO 8859-1 and convert it to UTF-8.
**********************************************************************/
#define WANTBYTES( want, got ) \
if( (want) > (got) ) { return; } else { (got) -= (want); }
static void strcatUTF8( char * s, int len, const char * append, int deslash )
{
const char * p;
/* don't overwrite the nul at the end */
len--;
/* Go to the end of the destination string */
while( s[0] )
{
s++;
len--;
}
/* Now start appending, converting on the fly if necessary */
for( p = append; p[0]; )
{
/* skip over / if requested */
if( deslash && '/' == p[0] )
{
p++;
continue;
}
if( !( p[0] & 0x80 ) )
{
/* ASCII character */
WANTBYTES( 1, len );
*(s++) = *(p++);
continue;
}
if( ( p[0] & 0xE0 ) == 0xC0 && ( p[1] & 0xC0 ) == 0x80 )
{
/* 2-bytes UTF-8 character */
WANTBYTES( 2, len );
*(s++) = *(p++); *(s++) = *(p++);
continue;
}
if( ( p[0] & 0xF0 ) == 0xE0 && ( p[1] & 0xC0 ) == 0x80 &&
( p[2] & 0xC0 ) == 0x80 )
{
/* 3-bytes UTF-8 character */
WANTBYTES( 3, len );
*(s++) = *(p++); *(s++) = *(p++);
*(s++) = *(p++);
continue;
}
if( ( p[0] & 0xF8 ) == 0xF0 && ( p[1] & 0xC0 ) == 0x80 &&
( p[2] & 0xC0 ) == 0x80 && ( p[3] & 0xC0 ) == 0x80 )
{
/* 4-bytes UTF-8 character */
WANTBYTES( 4, len );
*(s++) = *(p++); *(s++) = *(p++);
*(s++) = *(p++); *(s++) = *(p++);
continue;
}
/* ISO 8859-1 -> UTF-8 conversion */
WANTBYTES( 2, len );
*(s++) = 0xC0 | ( ( *p & 0xFF ) >> 6 );
*(s++) = 0x80 | ( *(p++) & 0x3F );
}
}
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