opentracker – An open and free bittorrent tracker
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/* This software was written by Dirk Engling <erdgeist@erdgeist.org>
It is considered beerware. Prost. Skol. Cheers or whatever. */
/* System */
#include <sys/types.h>
#include <sys/mman.h>
#include <stdio.h>
#include <string.h>
#include <pthread.h>
/* Libowfat */
#include "scan.h"
#include "byte.h"
/* Opentracker */
#include "trackerlogic.h"
#include "ot_mutex.h"
#include "ot_sync.h"
#ifdef WANT_TRACKER_SYNC
#define OT_SYNC_CHUNK_SIZE (512*1024)
/* Import Changeset from an external authority
format: d4:syncd[..]ee
[..]: ( 20:01234567890abcdefghij16:XXXXYYYY )+
*/
int add_changeset_to_tracker( ot_byte *data, size_t len ) {
ot_hash *hash;
ot_byte *end = data + len;
unsigned long peer_count;
/* We do know, that the string is \n terminated, so it cant
overflow */
if( byte_diff( data, 8, "d4:syncd" ) ) return -1;
data += 8;
while( 1 ) {
if( byte_diff( data, 3, "20:" ) ) {
if( byte_diff( data, 2, "ee" ) )
return -1;
return 0;
}
data += 3;
hash = (ot_hash*)data;
data += sizeof( ot_hash );
/* Scan string length indicator */
data += ( len = scan_ulong( (char*)data, &peer_count ) );
/* If no long was scanned, it is not divisible by 8, it is not
followed by a colon or claims to need to much memory, we fail */
if( !len || !peer_count || ( peer_count & 7 ) || ( *data++ != ':' ) || ( data + peer_count > end ) )
return -1;
while( peer_count > 0 ) {
add_peer_to_torrent( hash, (ot_peer*)data, 1 );
data += 8; peer_count -= 8;
}
}
return 0;
}
/* Proposed output format
d4:syncd20:<info_hash>8*N:(xxxxyyyy)*Nee
*/
static void sync_make( int *iovec_entries, struct iovec **iovector ) {
int bucket;
char *r, *re;
/* Setup return vector... */
*iovec_entries = 0;
*iovector = NULL;
if( !( r = iovec_increase( iovec_entries, iovector, OT_SYNC_CHUNK_SIZE ) ) )
return;
/* ... and pointer to end of current output buffer.
This works as a low watermark */
re = r + OT_SYNC_CHUNK_SIZE;
memmove( r, "d4:syncd", 8 ); r += 8;
/* For each bucket... */
for( bucket=0; bucket<OT_BUCKET_COUNT; ++bucket ) {
/* Get exclusive access to that bucket */
ot_vector *torrents_list = mutex_bucket_lock( bucket );
size_t tor_offset;
/* For each torrent in this bucket.. */
for( tor_offset=0; tor_offset<torrents_list->size; ++tor_offset ) {
/* Address torrents members */
ot_peerlist *peer_list = ( ((ot_torrent*)(torrents_list->data))[tor_offset] ).peer_list;
ot_hash *hash =&( ((ot_torrent*)(torrents_list->data))[tor_offset] ).hash;
const size_t byte_count = sizeof(ot_peer) * peer_list->changeset.size;
/* If we reached our low watermark in buffer... */
if( re - r <= (ssize_t)(/* strlen( "20:" ) == */ 3 + sizeof( ot_hash ) + /* strlen_max( "%zd" ) == */ 12 + byte_count ) ) {
/* crop current output buffer to the amount really used */
iovec_fixlast( iovec_entries, iovector, OT_SYNC_CHUNK_SIZE - ( re - r ) );
/* And allocate a fresh output buffer at the end of our buffers list */
if( !( r = iovec_increase( iovec_entries, iovector, OT_SYNC_CHUNK_SIZE ) ) ) {
/* If this fails: free buffers */
iovec_free( iovec_entries, iovector );
/* Release lock on current bucket and return */
mutex_bucket_unlock( bucket );
return;
}
/* Adjust new end of output buffer */
re = r + OT_SYNC_CHUNK_SIZE;
}
*r++ = '2'; *r++ = '0'; *r++ = ':';
memmove( r, hash, sizeof( ot_hash ) ); r += sizeof( ot_hash );
r += sprintf( r, "%zd:", byte_count );
memmove( r, peer_list->changeset.data, byte_count ); r += byte_count;
}
/* All torrents done: release lock on currenct bucket */
mutex_bucket_unlock( bucket );
}
/* Close bencoded sync dictionary */
*r++='e'; *r++='e';
/* Release unused memory in current output buffer */
iovec_fixlast( iovec_entries, iovector, OT_SYNC_CHUNK_SIZE - ( re - r ) );
}
/* This is the entry point into this worker thread
It grabs tasks from mutex_tasklist and delivers results back
*/
static void * sync_worker( void * args) {
int iovec_entries;
struct iovec *iovector;
args = args;
while( 1 ) {
ot_tasktype tasktype = TASK_SYNC_OUT;
ot_taskid taskid = mutex_workqueue_poptask( &tasktype );
sync_make( &iovec_entries, &iovector );
if( mutex_workqueue_pushresult( taskid, iovec_entries, iovector ) )
iovec_free( &iovec_entries, &iovector );
}
return NULL;
}
static pthread_t thread_id;
void sync_init( ) {
pthread_create( &thread_id, NULL, sync_worker, NULL );
}
void sync_deinit( ) {
pthread_cancel( thread_id );
}
void sync_deliver( int64 socket ) {
mutex_workqueue_pushtask( socket, TASK_SYNC_OUT );
}
#endif