ftp.c

        A;
        150 Opening BINARY mode data connection for /etc/passwd (2241
        bytes).  (ok, the file is being transfered)
	
        B:
        150 Opening ASCII mode data connection for /bin/ls 

        C:
        150 ASCII data connection for /bin/ls (137.167.104.91,37445) (0 bytes).

        D:
        150 Opening ASCII mode data connection for /linux/fisk/kpanelrc (0.0.0.0,0) (545 bytes).
          
        E:
        125 Data connection already open; Transfer starting. */

      curl_off_t size=-1; /* default unknown size */


      /*
       * It appears that there are FTP-servers that return size 0 for files
       * when SIZE is used on the file while being in BINARY mode. To work
       * around that (stupid) behavior, we attempt to parse the RETR response
       * even if the SIZE returned size zero.
       *
       * Debugging help from Salvatore Sorrentino on February 26, 2003.
       */

      if(!dirlist &&
         !data->set.ftp_ascii &&
         (downloadsize < 1)) {
        /*
         * It seems directory listings either don't show the size or very
         * often uses size 0 anyway. ASCII transfers may very well turn out
         * that the transfered amount of data is not the same as this line
         * tells, why using this number in those cases only confuses us.
         *
         * Example D above makes this parsing a little tricky */
        char *bytes;
        bytes=strstr(buf, " bytes");
        if(bytes--) {
          int in=bytes-buf;
          /* this is a hint there is size information in there! ;-) */
          while(--in) {
            /* scan for the parenthesis and break there */
            if('(' == *bytes)
              break;
            /* if only skip digits, or else we're in deep trouble */
            if(!isdigit((int)*bytes)) {
              bytes=NULL;
              break;
            }
            /* one more estep backwards */
            bytes--;
          }
          /* only if we have nothing but digits: */
          if(bytes++) {
            /* get the number! */
            size = strtoofft(bytes, NULL, 0);
          }
            
        }
      }
      else if(downloadsize > -1)
        size = downloadsize;

      if(data->set.ftp_use_port) {
        result = AllowServerConnect(conn);
        if( result )
          return result;
      }

      if(conn->ssl[SECONDARYSOCKET].use) {
	/* since we only have a plaintext TCP connection here, we must now
	   do the TLS stuff */
	infof(data, "Doing the SSL/TLS handshake on the data stream\n");
	result = Curl_SSLConnect(conn, SECONDARYSOCKET);
	if(result)
	  return result;
      }

      if(size > conn->maxdownload && conn->maxdownload > 0)
        size = conn->size = conn->maxdownload;

      infof(data, "Getting file with size: %Od\n", size);

      /* FTP download: */
      result=Curl_Transfer(conn, SECONDARYSOCKET, size, FALSE,
                           bytecountp,
                           -1, NULL); /* no upload here */
      if(result)
        return result;
    }
    else {
      if(dirlist && (ftpcode == 450)) {
        /* simply no matching files */
        ftp->no_transfer = TRUE; /* don't think we should download anything */
      }
      else {
        failf(data, "%s", buf+4);
        return CURLE_FTP_COULDNT_RETR_FILE;
      }
    }
	
  }
  /* end of transfer */

  return CURLE_OK;
}

/***********************************************************************
 *
 * ftp_perform()
 *
 * This is the actual DO function for FTP. Get a file/directory according to
 * the options previously setup.
 */

static
CURLcode ftp_perform(struct connectdata *conn,
                     bool *connected)  /* for the TCP connect status after
                                          PASV / PORT */
{
  /* this is FTP and no proxy */
  CURLcode result=CURLE_OK;
  struct SessionHandle *data=conn->data;
  char *buf = data->state.buffer; /* this is our buffer */

  /* the ftp struct is already inited in Curl_ftp_connect() */
  struct FTP *ftp = conn->proto.ftp;

  /* Send any QUOTE strings? */
  if(data->set.quote) {
    if ((result = ftp_sendquote(conn, data->set.quote)) != CURLE_OK)
      return result;
  }

  /* This is a re-used connection. Since we change directory to where the
     transfer is taking place, we must now get back to the original dir
     where we ended up after login: */
  if (conn->bits.reuse && ftp->entrypath) {
    if ((result = ftp_cwd_and_mkd(conn, ftp->entrypath)) != CURLE_OK)
      return result;
  }

  {
    int i; /* counter for loop */
    for (i=0; ftp->dirs[i]; i++) {
      /* RFC 1738 says empty components should be respected too, but
         that is plain stupid since CWD can't be used with an empty argument */
      if ((result = ftp_cwd_and_mkd(conn, ftp->dirs[i])) != CURLE_OK)
        return result;
    }
  }

  /* Requested time of file or time-depended transfer? */
  if((data->set.get_filetime || data->set.timecondition) &&
     ftp->file) {
    result = ftp_getfiletime(conn, ftp->file);
    switch( result )
      {
      case CURLE_FTP_COULDNT_RETR_FILE:
      case CURLE_OK:
        if(data->set.timecondition) {
          if((data->info.filetime > 0) && (data->set.timevalue > 0)) {
            switch(data->set.timecondition) {
            case CURL_TIMECOND_IFMODSINCE:
            default:
              if(data->info.filetime < data->set.timevalue) {
                infof(data, "The requested document is not new enough\n");
                ftp->no_transfer = TRUE; /* mark this to not transfer data */
                return CURLE_OK;
              }
              break;
            case CURL_TIMECOND_IFUNMODSINCE:
              if(data->info.filetime > data->set.timevalue) {
                infof(data, "The requested document is not old enough\n");
                ftp->no_transfer = TRUE; /* mark this to not transfer data */
                return CURLE_OK;
              }
              break;
            } /* switch */
          }
          else {
            infof(data, "Skipping time comparison\n");
          }
        }
        break;
      default:
        return result;
      } /* switch */
  }

  /* If we have selected NOBODY and HEADER, it means that we only want file
     information. Which in FTP can't be much more than the file size and
     date. */
  if(data->set.no_body && data->set.include_header && ftp->file) {
    /* The SIZE command is _not_ RFC 959 specified, and therefor many servers
       may not support it! It is however the only way we have to get a file's
       size! */
    curl_off_t filesize;
    ssize_t nread;
    int ftpcode;

    ftp->no_transfer = TRUE; /* this means no actual transfer is made */
    
    /* Some servers return different sizes for different modes, and thus we
       must set the proper type before we check the size */
    result = ftp_transfertype(conn, data->set.ftp_ascii);
    if(result)
      return result;

    /* failing to get size is not a serious error */
    result = ftp_getsize(conn, ftp->file, &filesize);

    if(CURLE_OK == result) {
      sprintf(buf, "Content-Length: %Od\r\n", filesize);
      result = Curl_client_write(data, CLIENTWRITE_BOTH, buf, 0);
      if(result)
        return result;
    }

    /* Determine if server can respond to REST command and therefore
       whether it can do a range */
    FTPSENDF(conn, "REST 0", NULL);
    result = Curl_GetFTPResponse(&nread, conn, &ftpcode);

    if ((CURLE_OK == result) && (ftpcode == 350)) {
      result = Curl_client_write(data, CLIENTWRITE_BOTH,
                                 (char *)"Accept-ranges: bytes\r\n", 0);
      if(result)
        return result;
    }

    /* If we asked for a time of the file and we actually got one as
       well, we "emulate" a HTTP-style header in our output. */

#ifdef HAVE_STRFTIME
    if(data->set.get_filetime && (data->info.filetime>=0) ) {
      struct tm *tm;
      time_t clock = (time_t)data->info.filetime;
#ifdef HAVE_GMTIME_R
      struct tm buffer;
      tm = (struct tm *)gmtime_r(&clock, &buffer);
#else
      tm = gmtime(&clock);
#endif
      /* format: "Tue, 15 Nov 1994 12:45:26" */
      strftime(buf, BUFSIZE-1, "Last-Modified: %a, %d %b %Y %H:%M:%S GMT\r\n",
               tm);
      result = Curl_client_write(data, CLIENTWRITE_BOTH, buf, 0);
      if(result)
        return result;
    }
#endif

    return CURLE_OK;
  }

  if(data->set.no_body)
    /* doesn't really transfer any data */
    ftp->no_transfer = TRUE;
  /* Get us a second connection up and connected */
  else if(data->set.ftp_use_port) {
    /* We have chosen to use the PORT command */
    result = ftp_use_port(conn);
    if(CURLE_OK == result) {
      /* we have the data connection ready */
      infof(data, "Ordered connect of the data stream with PORT!\n");
      *connected = TRUE; /* mark us "still connected" */
    }
  }
  else {
    /* We have chosen (this is default) to use the PASV command */
    result = ftp_use_pasv(conn, connected);
    if(CURLE_OK == result && *connected)
      infof(data, "Connected the data stream with PASV!\n");
  }
  
  return result;
}

/***********************************************************************
 *
 * Curl_ftp()
 *
 * This function is registered as 'curl_do' function. It decodes the path
 * parts etc as a wrapper to the actual DO function (ftp_perform).
 *
 * The input argument is already checked for validity.
 *
 * ftp->ctl_valid starts out as FALSE, and gets set to TRUE if we reach the
 * end of the function.
 */
CURLcode Curl_ftp(struct connectdata *conn)
{
  CURLcode retcode=CURLE_OK;
  bool connected=0;
  struct SessionHandle *data = conn->data;
  struct FTP *ftp;

  char *slash_pos;  /* position of the first '/' char in curpos */
  char *cur_pos=conn->ppath; /* current position in ppath. point at the begin
                                of next path component */
  int path_part=0;/* current path component */

  /* the ftp struct is already inited in ftp_connect() */
  ftp = conn->proto.ftp;
  ftp->ctl_valid = FALSE;
  conn->size = -1; /* make sure this is unknown at this point */

  Curl_pgrsSetUploadCounter(data, 0);
  Curl_pgrsSetDownloadCounter(data, 0);
  Curl_pgrsSetUploadSize(data, 0);
  Curl_pgrsSetDownloadSize(data, 0);

  /*  fixed : initialize ftp->dirs[xxx] to NULL !
      is done in Curl_ftp_connect() */

  /* parse the URL path into separate path components */
  while((slash_pos=strchr(cur_pos, '/'))) {
    /* 1 or 0 to indicate absolute directory */
    bool absolute_dir = (cur_pos - conn->ppath > 0) && (path_part == 0);

    /* seek out the next path component */
    if (slash_pos-cur_pos) {
      /* we skip empty path components, like "x//y" since the FTP command CWD
         requires a parameter and a non-existant parameter a) doesn't work on
         many servers and b) has no effect on the others. */
      ftp->dirs[path_part] = curl_unescape(cur_pos - absolute_dir,
                                           slash_pos - cur_pos + absolute_dir);
    
      if (!ftp->dirs[path_part]) { /* run out of memory ... */
        failf(data, "no memory");
        freedirs(ftp);
        return CURLE_OUT_OF_MEMORY;
      }
    }
    else {
      cur_pos = slash_pos + 1; /* jump to the rest of the string */
      continue;
    }

    if(!retcode) {
      cur_pos = slash_pos + 1; /* jump to the rest of the string */
      if(++path_part >= (CURL_MAX_FTP_DIRDEPTH-1)) {
        /* too deep, we need the last entry to be kept NULL at all
           times to signal end of list */
        failf(data, "too deep dir hierarchy");
        freedirs(ftp);
        return CURLE_URL_MALFORMAT;
      }
    }
  }

  ftp->file = cur_pos;  /* the rest is the file name */

  if(*ftp->file) {
    ftp->file = curl_unescape(ftp->file, 0);
    if(NULL == ftp->file) {
      freedirs(ftp);
      failf(data, "no memory");
      return CURLE_OUT_OF_MEMORY;
    }
  }
  else
    ftp->file=NULL; /* instead of point to a zero byte, we make it a NULL
                       pointer */
  
  retcode = ftp_perform(conn, &connected);

  if(CURLE_OK == retcode) {
    if(connected)
      retcode = Curl_ftp_nextconnect(conn);

    if(retcode && (conn->sock[SECONDARYSOCKET] >= 0)) {
      /* Failure detected, close the second socket if it was created already */
      sclose(conn->sock[SECONDARYSOCKET]);
      conn->sock[SECONDARYSOCKET] = -1;
    }

    if(ftp->no_transfer)
      /* no data to transfer */
      retcode=Curl_Transfer(conn, -1, -1, FALSE, NULL, -1, NULL);        
    else if(!connected)
      /* since we didn't connect now, we want do_more to get called */
      conn->bits.do_more = TRUE;
  }
  else
    freedirs(ftp);

  ftp->ctl_valid = TRUE;
  return retcode;
}

/***********************************************************************
 *
 * Curl_ftpsendf()
 *
 * Sends the formated string as a ftp command to a ftp server
 *
 * NOTE: we build the command in a fixed-length buffer, which sets length
 * restrictions on the command!
 */
CURLcode Curl_ftpsendf(struct connectdata *conn,
                       const char *fmt, ...)
{
  ssize_t bytes_written;
  char s[256];
  ssize_t write_len;
  char *sptr=s;
  CURLcode res = CURLE_OK;

  va_list ap;
  va_start(ap, fmt);
  vsnprintf(s, 250, fmt, ap);
  va_end(ap);
  
  strcat(s, "\r\n"); /* append a trailing CRLF */

  bytes_written=0;
  write_len = strlen(s);

  while(1) {
    res = Curl_write(conn, conn->sock[FIRSTSOCKET], sptr, write_len,
                     &bytes_written);

    if(CURLE_OK != res)
      break;

    if(conn->data->set.verbose)
      Curl_debug(conn->data, CURLINFO_HEADER_OUT, sptr, bytes_written);

    if(bytes_written != write_len) {
      write_len -= bytes_written;
      sptr += bytes_written;
    }
    else
      break;
  }

  return res;
}

/***********************************************************************
 *
 * Curl_ftp_quit()
 *
 * This should be called before calling sclose() on an ftp control connection
 * (not data connections). We should then wait for the response from the 
 * server before returning. The calling code should then try to close the
 * connection.
 *
 */
CURLcode Curl_ftp_quit(struct connectdata *conn)
{
  ssize_t nread;
  int ftpcode;
  CURLcode ret = CURLE_OK;

  if(conn->proto.ftp->ctl_valid) {
    ret = Curl_ftpsendf(conn, "%s", "QUIT");
    if(CURLE_OK == ret)
      ret = Curl_GetFTPResponse(&nread, conn, &ftpcode);
  }

  return ret;
}

/***********************************************************************
 *
 * Curl_ftp_disconnect()
 *
 * Disconnect from an FTP server. Cleanup protocol-specific per-connection
 * resources
 */
CURLcode Curl_ftp_disconnect(struct connectdata *conn)
{
  struct FTP *ftp= conn->proto.ftp;

  /* We cannot send quit unconditionally. If this connection is stale or
     bad in any way, sending quit and waiting around here will make the
     disconnect wait in vain and cause more problems than we need to.

     Curl_ftp_quit() will check the state of ftp->ctl_valid. If it's ok it
     will try to send the QUIT command, otherwise it will just return.
  */
  (void)Curl_ftp_quit(conn); /* ignore errors on the QUIT */

  /* The FTP session may or may not have been allocated/setup at this point! */
  if(ftp) {
    if(ftp->entrypath)
      free(ftp->entrypath);
    if(ftp->cache) {
      free(ftp->cache);
      ftp->cache = NULL;
    }
    if(ftp->file) {
      free(ftp->file);
      ftp->file = NULL; /* zero */
    }
    freedirs(ftp);
  }
  return CURLE_OK;
}

/***********************************************************************
 *
 * ftp_mkd()
 *
 * Makes a directory on the FTP server.
 *
 * Calls failf()
 */
CURLcode ftp_mkd(struct connectdata *conn, char *path)
{
  CURLcode result=CURLE_OK;
  int ftpcode; /* for ftp status */
  ssize_t nread;

  /* Create a directory on the remote server */
  FTPSENDF(conn, "MKD %s", path);

  result = Curl_GetFTPResponse(&nread, conn, &ftpcode);
  if(result)
    return result;
  
  switch(ftpcode) {
  case 257:
    /* success! */
    infof( conn->data , "Created remote directory %s\n" , path );
    break;
  case 550:
    failf(conn->data, "Permission denied to make directory %s", path);
    result = CURLE_FTP_ACCESS_DENIED;
    break;
  default:
    failf(conn->data, "unrecognized MKD response: %d", ftpcode );
    result = CURLE_FTP_ACCESS_DENIED;
    break;
  }
  return  result;
}

/***********************************************************************
 *
 * ftp_cwd()
 *
 * Send 'CWD' to the remote server to Change Working Directory.  It is the ftp
 * version of the unix 'cd' command. This function is only called from the
 * ftp_cwd_and_mkd() function these days.
 *
 * This function does NOT call failf().
 */
static 
CURLcode ftp_cwd(struct connectdata *conn, char *path)
{
  ssize_t nread;
  int     ftpcode;
  CURLcode result;
  
  FTPSENDF(conn, "CWD %s", path);
  result = Curl_GetFTPResponse(&nread, conn, &ftpcode);
  if (!result) {
    /* According to RFC959, CWD is supposed to return 250 on success, but
       there seem to be non-compliant FTP servers out there that return 200,
       so we accept any '2xy' code here. */
    if (ftpcode/100 != 2)
      result = CURLE_FTP_ACCESS_DENIED;
  }

  return result;
}

/***********************************************************************
 *
 * ftp_cwd_and_mkd()
 *
 * Change to the given directory.  If the directory is not present, and we
 * have been told to allow it, then create the directory and cd to it.
 *
 */
static CURLcode ftp_cwd_and_mkd(struct connectdata *conn, char *path)
{
  CURLcode result;
  
  result = ftp_cwd(conn, path);
  if (result) {
    if(conn->data->set.ftp_create_missing_dirs) {
      result = ftp_mkd(conn, path);
      if (result)
        /* ftp_mkd() calls failf() itself */
        return result;
      result = ftp_cwd(conn, path);
    }
    if(result)
      failf(conn->data, "Couldn't cd to %s", path);
  }
  return result;
}

#endif /* CURL_DISABLE_FTP */