btcontent.cpp

在嵌入linux-arm上运行的bt下载应用程序

#include "btcontent.h"

#ifdef WINDOWS
#include <direct.h>
#include <io.h>
#include <memory.h>
// include windows sha1 header here.

#else
#include <unistd.h>
#include <sys/param.h>
#if defined(HAVE_LIBCRYPT) || defined(HAVE_LIBMD) || defined(HAVE_LIBCRYPTO)
#include <sha.h>
#elif defined(HAVE_LIBSSL)
#include <libsha-08.2b/sha.h>
#endif
#endif

#include <time.h>
#include <sys/stat.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <errno.h>

#include "btconfig.h"
#include "bencode.h"
#include "peer.h"
#include "httpencode.h"
#include "tracker.h"

#if defined(USE_STANDALONE_SHA1)
#include "sha1.h"
#endif

#define meta_str(keylist,pstr,pint) decode_query(b,flen,(keylist),(pstr),(pint),(int64_t*) 0,QUERY_STR)
#define meta_int(keylist,pint) decode_query(b,flen,(keylist),(const char**) 0,(pint),(int64_t*) 0,QUERY_INT)
#define meta_pos(keylist) decode_query(b,flen,(keylist),(const char**) 0,(size_t*) 0,(int64_t*) 0,QUERY_POS)

#define CACHE_FIT(ca,roff,rlen)	\
(max_u_int64_t((ca)->bc_off,(roff)) <= \
 min_u_int64_t(((ca)->bc_off + (ca)->bc_len - 1),(roff + rlen - 1)))

#define MAX_OPEN_FILES 20

btContent BTCONTENT;

static void Sha1(char *ptr,size_t len,unsigned char *dm)
{
#if defined(USE_STANDALONE_SHA1)
  SHA1_CTX context;
  SHA1Init(&context);
  SHA1Update(&context,(unsigned char*)ptr,len);
  SHA1Final(dm,&context);
#else
#ifdef WINDOWS
  ;
#else
  SHA_CTX context;
  SHA1_Init(&context);
  SHA1_Update(&context,(unsigned char*)ptr,len);
  SHA1_Final(dm,&context);
#endif
#endif
}

btContent::btContent()
{
  m_announce = global_piece_buffer = (char*) 0;
  m_hash_table = (unsigned char *) 0;
  pBF = (BitField*) 0;
  pBFilter = (BitField*) 0;
  m_create_date = m_seed_timestamp = (time_t) 0;
  time(&m_start_timestamp);
  m_cache = (BTCACHE*) 0;
  m_cache_size = m_cache_used = 0;
}

int btContent::CreateMetainfoFile(const char *mifn)
{
  FILE *fp;
  fp = fopen(mifn, "r");
  if( fp ){
    fprintf(stderr,"error, file %s already exist.\n",mifn);
    return -1;
  }else if( ENOENT != errno ){
    fprintf(stderr,"error, couldn't create %s.\n",mifn);
    return -1;
  }

  fp = fopen(mifn, "w");

  if( !fp ){
    fprintf(stderr,"error, open %s failed. %s\n",mifn, strerror(errno));
    return -1;
  }
  if( bencode_begin_dict(fp) != 1 ) goto err;

  // announce
  if( bencode_str("announce", fp) != 1 ) goto err;
  if( bencode_str(m_announce, fp) !=1 ) goto err;
  // create date
  if( bencode_str("creation date", fp) != 1) goto err;
  if( bencode_int(m_create_date, fp) != 1 ) goto err;

  // info dict
  if( bencode_str("info", fp) != 1) goto err;
  if( bencode_begin_dict(fp) != 1 ) goto err;

  if( m_btfiles.FillMetaInfo(fp) != 1 ) goto err;

  // piece length
  if( bencode_str("piece length", fp) != 1 ) goto err;
  if( bencode_int(m_piece_length, fp) != 1 ) goto err;
  
  // hash table;
  if( bencode_str("pieces", fp) != 1) goto err;
  if( bencode_buf((const char*) m_hash_table, m_hashtable_length, fp) != 1 ) goto err;

  if( bencode_end_dict_list(fp) != 1 ) goto err; // end info
  if( bencode_end_dict_list(fp) != 1 ) goto err; // end torrent

  fclose(fp);
  return 0;
 err:
  if( fp ) fclose(fp);
  return -1;
}

int btContent::InitialFromFS(const char *pathname, char *ann_url, size_t piece_length)
{
  size_t n, percent;

  // piece length
  m_piece_length = piece_length;
  if( m_piece_length % 65536 ){ 
    m_piece_length /= 65536;
    m_piece_length *= 65536;
  }

  // This is really just a sanity check on the piece length to create.
  if( !m_piece_length || m_piece_length > 4096*1024 )
    m_piece_length = 262144;
  
  m_announce = ann_url;
  m_create_date = time((time_t*) 0);

  if(m_btfiles.BuildFromFS(pathname) < 0) return -1;

  global_piece_buffer = new char[m_piece_length];
#ifndef WINDOWS
  if( !global_piece_buffer ) return -1;
#endif
  
  // n pieces
  m_npieces = m_btfiles.GetTotalLength() / m_piece_length;
  if( m_btfiles.GetTotalLength() % m_piece_length ) m_npieces++;

  // create hash table.
  m_hashtable_length = m_npieces * 20;
  m_hash_table = new unsigned char[m_hashtable_length];
#ifndef WINDOWS
  if( !m_hash_table ) return -1;
#endif

  percent = m_npieces / 100;
  if( !percent ) percent = 1;

  for( n = 0; n < m_npieces; n++){
    if( GetHashValue(n, m_hash_table + n * 20) < 0) return -1;
    if( 0 == n % percent ){
      printf("\rCreate hash table: %u/%u", n, m_npieces);
      fflush(stdout);
    }
  }
  printf("Complete.\n");

  return 0;
}

int btContent::PrintOut()
{
  printf("META INFO\n");
  printf("Announce: %s\n",m_announce);
  if( m_create_date ) printf("Created On: %s",ctime(&m_create_date));
  printf("Piece length: %u\n\n",m_piece_length);
  m_btfiles.PrintOut();
  return 0;
}

int btContent::InitialFromMI(const char *metainfo_fname,const char *saveas)
{
#define ERR_RETURN()	{if(b) delete []b; return -1;}
  unsigned char *ptr = m_shake_buffer;
  char *b;
  const char *s;
  size_t flen, q, r;

  b = _file2mem(metainfo_fname,&flen);
  if ( !b ) return -1;

  // announce
  if( !meta_str("announce",&s,&r) ) ERR_RETURN();
  if( r > MAXPATHLEN ) ERR_RETURN();
  m_announce = new char [r + 1];
  memcpy(m_announce, s, r);
  m_announce[r] = '\0';
  
  // infohash
  if( !(r = meta_pos("info")) ) ERR_RETURN();
  if( !(q = decode_dict(b + r, flen - r, (char *) 0)) ) ERR_RETURN();
  Sha1(b + r, q, m_shake_buffer + 28);

  if( meta_int("creation date",&r)) m_create_date = (time_t) r;
 
  // hash table
  if( !meta_str("info|pieces",&s,&m_hashtable_length) ||
      m_hashtable_length % 20 != 0) ERR_RETURN();

  m_hash_table = new unsigned char[m_hashtable_length];

#ifndef WINDOWS
  if( !m_hash_table ) ERR_RETURN();
#endif
  memcpy(m_hash_table, s, m_hashtable_length);

  if(!meta_int("info|piece length",&m_piece_length)) ERR_RETURN();
  m_npieces = m_hashtable_length / 20;

  cfg_req_queue_length = (m_piece_length / cfg_req_slice_size) * 2 - 1;

  if( m_piece_length < cfg_req_slice_size )
    cfg_req_slice_size = m_piece_length;
  
  if( m_btfiles.BuildFromMI(b, flen, saveas) < 0) ERR_RETURN();

  delete []b;
  b = (char *)0;
  
  if( arg_flg_exam_only ){
    PrintOut();
    return 0;
  }else{
    arg_flg_exam_only = 1;
    PrintOut();
    arg_flg_exam_only = 0;
  }

  if( ( r = m_btfiles.CreateFiles() ) < 0) ERR_RETURN();

  global_piece_buffer = new char[m_piece_length];
#ifndef WINDOWS
  if( !global_piece_buffer ) ERR_RETURN();
#endif

  pBF = new BitField(m_npieces);
#ifndef WINDOWS
  if( !pBF ) ERR_RETURN();
#endif

    //create the file filter
    pBFilter = new BitField(m_npieces);
#ifndef WINDOWS
     if( !pBFilter ) ERR_RETURN();
#endif
  if(arg_file_to_download>0){
    m_btfiles.SetFilter(arg_file_to_download,pBFilter,m_piece_length);
  }



  m_left_bytes = m_btfiles.GetTotalLength() / m_piece_length;
  if( m_btfiles.GetTotalLength() % m_piece_length ) m_left_bytes++;
  if( m_left_bytes != m_npieces ) ERR_RETURN();
  
  m_left_bytes = m_btfiles.GetTotalLength();

  if( arg_bitfield_file ){

    if( !arg_flg_check_only ){
      if( pBF->SetReferFile(arg_bitfield_file) >= 0){
        size_t idx;
        r = 0;
        for( idx = 0; idx < m_npieces; idx++ )
          if( pBF->IsSet(idx) ) m_left_bytes -= GetPieceLength(idx);
      }
      else{
        fprintf(stderr,"warn, couldn't set bit field refer file %s.\n",arg_bitfield_file);
      }
    }
    
    if( r ) CheckExist();
    
  }else if( arg_flg_force_seed_mode ){
    pBF->SetAll();
    m_left_bytes = 0;
  }else if( r ){
    CheckExist();
  }
  
  PrintOut();
  printf("Already/Total: %u/%u (%d%%)\n",pBF->Count(),m_npieces,
    100 * pBF->Count() / m_npieces);
  
  if( arg_flg_check_only ){
    if( arg_bitfield_file ) pBF->WriteToFile(arg_bitfield_file);
    exit(1);
  }
  
  CacheConfigure();

  *ptr = (unsigned char) 19; ptr++; // protocol string length
  memcpy(ptr,"BitTorrent protocol",19); ptr += 19; //  protocol string
  memset(ptr,0,8);		// reserved set zero.

  {				// peer id
        char *sptr = arg_user_agent;
        char *dptr = (char *)m_shake_buffer + 48;
        char *eptr = dptr + PEER_ID_LEN;
        while (*sptr) *dptr++ = *sptr++;
        while (dptr < eptr) *dptr++ = (unsigned char)random();
  }
  return 0;
}

btContent::~btContent()
{
  if(m_hash_table) delete []m_hash_table;
  if(m_announce) delete []m_announce;
  if(global_piece_buffer) delete []global_piece_buffer;
  if(pBF) delete pBF;
}

void btContent::_Set_InfoHash(unsigned char buf[20]) 
{ 
  memcpy(m_shake_buffer + 28, buf, 20);
}

ssize_t btContent::ReadSlice(char *buf,size_t idx,size_t off,size_t len)
{
  //changed
  u_int64_t offset = (u_int64_t)idx * (u_int64_t)m_piece_length + (u_int64_t)off;

  if( !m_cache_size ) return m_btfiles.IO(buf, offset, len, 0);
  else{
    size_t len2;