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311 lines
11 KiB
311 lines
11 KiB
#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( char *directory ) { |
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glob_t globber; |
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int i; |
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if( directory ) |
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chdir( directory ); |
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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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