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309 lines
11 KiB
C
309 lines
11 KiB
C
#include "trackerlogic.h"
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#include <stdlib.h>
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#include <string.h>
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#include <stdio.h>
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#include <fcntl.h>
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#include <sys/types.h>
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#include <sys/mman.h>
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#include <unistd.h>
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#include <time.h>
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#include <glob.h>
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// Helper functions for binary_find
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//
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int compare_hash( const void *hash1, const void *hash2 ) { return memcmp( hash1, hash2, sizeof( ot_hash )); }
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int compare_ip_port( const void *peer1, const void *peer2 ) { return memcmp( &((ot_peer)peer1)->ip, &((ot_peer)peer2)->ip, 6); }
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void *binary_search( const void *key, const void *base,
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unsigned long member_count, const unsigned long member_size,
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int (*compar) (const void *, const void *),
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int *exactmatch ) {
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ot_byte *lookat = ((ot_byte*)base) + member_size * (member_count >> 1);
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*exactmatch = 1;
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while( member_count ) {
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int cmp = compar((void*)lookat, key);
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if (cmp == 0) return (void *)lookat;
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if (cmp < 0) {
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base = (void*)(lookat + member_size);
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--member_count;
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}
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member_count >>= 1;
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lookat = ((ot_byte*)base) + member_size * (member_count >> 1);
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}
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*exactmatch = 0;
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return (void*)lookat;
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}
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// Converter function from memory to human readable hex strings
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// * definitely not thread safe!!!
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//
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char ths[1+2*20];char *to_hex(ot_byte*s){char*m="0123456789ABCDEF";char*e=ths+40;char*t=ths;while(t<e){*t++=m[*s>>4];*t++=m[*s++&15];}*t=0;return ths;}
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// GLOBAL VARIABLES
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//
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unsigned long torrents_count = 0;
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ot_torrent torrents_list = 0;
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ot_byte *scratch_space = 0;
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#define SETINVALID( i ) (scratch_space[index] = 3);
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#define SETSELECTED( i ) (scratch_space[index] = 1);
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#define TESTSELECTED( i ) (scratch_space[index] == 1 )
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#define TESTSET( i ) (scratch_space[index])
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#define RANDOM random()
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ot_torrent add_peer_to_torrent( ot_hash hash, ot_peer peer ) {
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ot_torrent torrent;
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ot_peer peer_dest;
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int exactmatch;
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torrent = BINARY_FIND( hash, torrents_list, torrents_count, sizeof( *torrent ), compare_hash, &exactmatch );
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if( !exactmatch ) {
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// Assume, OS will provide us with space, after all, this is file backed
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MEMMOVE( torrent + 1, torrent, ( torrents_list + torrents_count ) - torrent );
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// Create a new torrent entry, then
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MEMMOVE( &torrent->hash, hash, sizeof( ot_hash ) );
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torrent->peer_list = map_file( to_hex( hash ) );
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torrent->peer_count = 0;
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torrent->seed_count = 0;
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}
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peer_dest = BINARY_FIND( peer, torrent->peer_list, torrent->peer_count, sizeof( *peer_dest ), compare_ip_port, &exactmatch );
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if( exactmatch ) {
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// If peer was a seeder but isn't anymore, decrease seeder count
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if( ( peer_dest->flags & PEER_FLAG_SEEDING ) && !( peer->flags & PEER_FLAG_SEEDING ) )
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torrent->seed_count--;
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if( !( peer_dest->flags & PEER_FLAG_SEEDING ) && ( peer->flags & PEER_FLAG_SEEDING ) )
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torrent->seed_count++;
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} else {
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// Assume, OS will provide us with space, after all, this is file backed
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MEMMOVE( peer_dest + 1, peer_dest, ( torrent->peer_list + torrent->peer_count ) - peer_dest );
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// Create a new peer entry, then
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MEMMOVE( peer_dest, peer, sizeof( ot_peer ) );
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torrent->peer_count++;
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torrent->seed_count+= ( peer->flags & PEER_FLAG_SEEDING ) ? 1 : 0;
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}
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// Set new time out time
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peer_dest->death = NOW + OT_TIMEOUT;
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return torrent;
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}
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inline int TESTVALIDPEER( ot_peer p ) { return p->death > NOW; }
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// Compiles a list of random peers for a torrent
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// * scratch space keeps track of death or already selected peers
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// * reply must have enough space to hold 1+(1+16+2+1)*amount+1 bytes
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// * Selector function can be anything, maybe test for seeds, etc.
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// * that RANDOM may return huge values
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// * does not yet check not to return self
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// * it is not guaranteed to see all peers, so no assumptions on active seeders/peers may be done
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// * since compact format cannot handle v6 addresses, it must be enabled by OT_COMPACT_ONLY
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//
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void return_peers_for_torrent( ot_torrent torrent, unsigned long amount, char *reply ) {
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register ot_peer peer_base = torrent->peer_list;
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unsigned long peer_count = torrent->peer_count;
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unsigned long selected_count = 0, invalid_count = 0;
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unsigned long index = 0;
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// optimize later ;)
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BZERO( scratch_space, peer_count );
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while( ( selected_count < amount ) && ( selected_count + invalid_count < peer_count ) ) {
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// skip to first non-flagged peer
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while( TESTSET(index) ) index = ( index + 1 ) % peer_count;
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if( TESTVALIDPEER( peer_base + index ) ) {
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SETINVALID(index); invalid_count++;
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} else {
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SETSELECTED(index); selected_count++;
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index = ( index + RANDOM ) % peer_count;
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}
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}
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// Now our scratchspace contains a list of selected_count valid peers
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// Collect them into a reply string
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index = 0;
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#ifndef OT_COMPACT_ONLY
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reply += FORMAT_FIXED_STRING( reply, "d5:peersl" );
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#else
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reply += FORMAT_FORMAT_STRING( reply, "d5:peers%li:",6*selected_count );
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#endif
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while( selected_count-- ) {
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ot_peer peer;
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while( !TESTSELECTED( index ) ) ++index;
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peer = peer_base + index;
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#ifdef OT_COMPACT_ONLY
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MEMMOVE( reply, &peer->ip, 4 );
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MEMMOVE( reply+4, &peer->port, 2 );
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reply += 6;
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#else
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reply += FORMAT_FORMAT_STRING( reply, "d2:ip%d:%s7:peer id20:%20c4:porti%ie",
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peer->flags & PEER_IP_LENGTH_MASK,
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peer->ip,
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peer->id,
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peer->port );
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#endif
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}
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#ifndef OT_COMPACT_ONLY
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reply += FORMAT_FIXED_STRING( reply, "ee" );
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#else
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reply += FORMAT_FIXED_STRING( reply, "e" );
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#endif
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}
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// Compacts a torrents peer list
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// * torrents older than OT_TIMEOUT are being kicked
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// * is rather expansive
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// * if this fails, torrent file is invalid, should add flag
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//
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void heal_torrent( ot_torrent torrent ) {
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unsigned long index = 0, base = 0, end, seed_count = 0, now = NOW;
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// Initialize base to first dead peer.
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while( ( base < torrent->peer_count ) && torrent->peer_list[base].death <= now ) {
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seed_count += ( torrent->peer_list[base].flags & PEER_FLAG_SEEDING ) ? 1 : 0;
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base++;
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}
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// No dead peers? Home.
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if( base == torrent->peer_count ) return;
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// From now index always looks to the next living peer while base keeps track of
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// the dead peer that marks the beginning of insert space.
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index = base + 1;
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while( 1 ) {
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// Let index search for next living peer
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while( ( index < torrent->peer_count ) && torrent->peer_list[index].death > now ) index++;
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// No further living peers found - base is our new peer count
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if( index == torrent->peer_count ) {
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torrent->peer_count = base;
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torrent->seed_count = seed_count;
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return;
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}
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end = index + 1;
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// Let end search for next dead peer (end of living peers)
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while( ( end < torrent->peer_count ) && torrent->peer_list[end].death <= now ) {
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seed_count += ( torrent->peer_list[end].flags & PEER_FLAG_SEEDING ) ? 1 : 0;
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end++;
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}
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// We either hit a dead peer or the end of our peers
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// In both cases: move block towards base
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MEMMOVE( torrent->peer_list + base, torrent->peer_list + index, ( end - index ) * sizeof( struct ot_peer ) );
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base += end - index;
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index = end;
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}
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}
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void dispose_torrent( ot_torrent torrent ) {
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unmap_file( "", torrent->peer_list, 0 );
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unlink( to_hex( torrent->hash ) );
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MEMMOVE( torrent, torrent + 1, ( torrents_list + torrents_count ) - ( torrent + 1 ) );
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torrents_count--;
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}
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// This function maps a "huge" file into process space
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// * giving no name will aqcuire anonymous growable memory
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// * memory will not be "freed" from systems vm if once used, until unmap_file
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// * I guess, we should be checking for more errors...
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//
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void *map_file( char *file_name ) {
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char *map;
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if( file_name ) {
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int file_desc=open(file_name,O_RDWR|O_CREAT|O_NDELAY,0644);
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if( file_desc < 0) return 0;
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lseek( file_desc, OT_HUGE_FILESIZE, SEEK_SET );
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map=mmap(0,OT_HUGE_FILESIZE,PROT_READ|PROT_WRITE,MAP_SHARED,file_desc,0);
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close(file_desc);
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} else
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map=mmap(0,OT_HUGE_FILESIZE,PROT_READ|PROT_WRITE,MAP_ANON,-1,0);
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return (map == (char*)-1) ? 0 : map;
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}
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void unmap_file( char *file_name, void *map, unsigned long real_size ) {
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munmap( map, OT_HUGE_FILESIZE );
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if( file_name)
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truncate( file_name, real_size );
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}
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void count_peers_and_seeds( ot_peer peer_list, unsigned long *peers, unsigned long *seeds ) {
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*peers = *seeds = 0;
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if( peer_list[*peers].ip )
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do {
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*seeds += peer_list[*peers++].flags & PEER_FLAG_SEEDING ? 1 : 0;
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} while( compare_ip_port( peer_list + *peers, peer_list + *peers - 1 ) < 0 );
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}
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int init_logic( ) {
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glob_t globber;
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int i;
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scratch_space = map_file( "" );
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torrents_list = map_file( "" );
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torrents_count = 0;
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if( !scratch_space || !torrents_list ) {
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if( scratch_space || torrents_list )
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unmap_file( "", scratch_space ? (void*)scratch_space : (void*)torrents_list, 0 );
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return -1;
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}
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// Scan directory for filenames in the form [0-9A-F]{20}
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// * I know this looks ugly, but I've seen A-F to match umlauts as well in strange locales
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// * lower case for .. better being safe than sorry, this is not expansive here :)
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if( !glob(
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"[0-9ABCDEFabcdef][0-9ABCDEFabcdef][0-9ABCDEFabcdef][0-9ABCDEFabcdef]"
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"[0-9ABCDEFabcdef][0-9ABCDEFabcdef][0-9ABCDEFabcdef][0-9ABCDEFabcdef]"
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"[0-9ABCDEFabcdef][0-9ABCDEFabcdef][0-9ABCDEFabcdef][0-9ABCDEFabcdef]"
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"[0-9ABCDEFabcdef][0-9ABCDEFabcdef][0-9ABCDEFabcdef][0-9ABCDEFabcdef]"
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"[0-9ABCDEFabcdef][0-9ABCDEFabcdef][0-9ABCDEFabcdef][0-9ABCDEFabcdef]"
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"[0-9ABCDEFabcdef][0-9ABCDEFabcdef][0-9ABCDEFabcdef][0-9ABCDEFabcdef]"
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"[0-9ABCDEFabcdef][0-9ABCDEFabcdef][0-9ABCDEFabcdef][0-9ABCDEFabcdef]"
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"[0-9ABCDEFabcdef][0-9ABCDEFabcdef][0-9ABCDEFabcdef][0-9ABCDEFabcdef]"
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"[0-9ABCDEFabcdef][0-9ABCDEFabcdef][0-9ABCDEFabcdef][0-9ABCDEFabcdef]"
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"[0-9ABCDEFabcdef][0-9ABCDEFabcdef][0-9ABCDEFabcdef][0-9ABCDEFabcdef]"
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, GLOB_NOCHECK, 0, &globber) )
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{
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for( i=0; i<globber.gl_matchc; ++i ) {
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#ifdef _DEBUG
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printf( "Found dir: %s\n", globber.gl_pathv[i] );
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#endif
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if( ( torrents_list[torrents_count].peer_list = map_file( globber.gl_pathv[i] ) ) ) {
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MEMMOVE( &torrents_list[torrents_count].hash, globber.gl_pathv[i], sizeof( ot_hash ) );
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count_peers_and_seeds( torrents_list[torrents_count].peer_list,
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&torrents_list[torrents_count].peer_count,
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&torrents_list[torrents_count].seed_count );
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torrents_count++;
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}
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}
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}
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globfree( &globber );
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return 0;
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}
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void deinit_logic( ) {
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// For all torrents... blablabla
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while( torrents_count-- )
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unmap_file( to_hex(torrents_list[torrents_count].hash), torrents_list[torrents_count].peer_list, torrents_list[torrents_count].peer_count * sizeof(struct ot_peer) );
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unmap_file( "", torrents_list, 0 );
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unmap_file( "", scratch_space, 0 );
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}
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