telnet.c

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  char varname[128];
  char varval[128];
  struct SessionHandle *data = conn->data;
  struct TELNET *tn = (struct TELNET *)conn->proto.telnet;

  printsub(data, '<', (unsigned char *)tn->subbuffer, CURL_SB_LEN(tn)+2);
  switch (subchar = CURL_SB_GET(tn)) {
    case CURL_TELOPT_TTYPE:
      len = strlen(tn->subopt_ttype) + 4 + 2;
      snprintf((char *)temp, sizeof(temp),
               "%c%c%c%c%s%c%c", CURL_IAC, CURL_SB, CURL_TELOPT_TTYPE,
               CURL_TELQUAL_IS, tn->subopt_ttype, CURL_IAC, CURL_SE);
      (void)swrite(conn->firstsocket, temp, len);
      printsub(data, '>', &temp[2], len-2);
      break;
    case CURL_TELOPT_XDISPLOC:
      len = strlen(tn->subopt_xdisploc) + 4 + 2;
      snprintf((char *)temp, sizeof(temp),
               "%c%c%c%c%s%c%c", CURL_IAC, CURL_SB, CURL_TELOPT_XDISPLOC,
               CURL_TELQUAL_IS, tn->subopt_xdisploc, CURL_IAC, CURL_SE);
      (void)swrite(conn->firstsocket, temp, len);
      printsub(data, '>', &temp[2], len-2);
      break;
    case CURL_TELOPT_NEW_ENVIRON:
      snprintf((char *)temp, sizeof(temp),
               "%c%c%c%c", CURL_IAC, CURL_SB, CURL_TELOPT_NEW_ENVIRON,
               CURL_TELQUAL_IS);
      len = 4;

      for(v = tn->telnet_vars;v;v = v->next) {
        tmplen = (strlen(v->data) + 1);
        /* Add the variable only if it fits */
        if(len + tmplen < (int)sizeof(temp)-6) {
          sscanf(v->data, "%127[^,],%s", varname, varval);
          snprintf((char *)&temp[len], sizeof(temp) - len,
                   "%c%s%c%s", CURL_NEW_ENV_VAR, varname,
                   CURL_NEW_ENV_VALUE, varval);
          len += tmplen;
        }
      }
      snprintf((char *)&temp[len], sizeof(temp) - len,
               "%c%c", CURL_IAC, CURL_SE);
      len += 2;
      (void)swrite(conn->firstsocket, temp, len);
      printsub(data, '>', &temp[2], len-2);
      break;
  }
  return;
}

static
void telrcv(struct connectdata *conn,
            unsigned char *inbuf,	/* Data received from socket */
            int count)			/* Number of bytes received */
{
  unsigned char c;
  int in = 0;
  struct SessionHandle *data = conn->data;
  struct TELNET *tn = (struct TELNET *)conn->proto.telnet;

  while(count--)
  {
    c = inbuf[in++];

    switch (tn->telrcv_state)
    {
      case CURL_TS_CR:
        tn->telrcv_state = CURL_TS_DATA;
        if (c == '\0')
        {
          break;   /* Ignore \0 after CR */
        }

        Curl_client_write(data, CLIENTWRITE_BODY, (char *)&c, 1);
        continue;

      case CURL_TS_DATA:
        if (c == CURL_IAC)
        {
          tn->telrcv_state = CURL_TS_IAC;
          break;
        }
        else if(c == '\r')
        {
          tn->telrcv_state = CURL_TS_CR;
        }

        Curl_client_write(data, CLIENTWRITE_BODY, (char *)&c, 1);
        continue;

      case CURL_TS_IAC:
      process_iac:
      switch (c)
      {
        case CURL_WILL:
          tn->telrcv_state = CURL_TS_WILL;
          continue;
        case CURL_WONT:
          tn->telrcv_state = CURL_TS_WONT;
          continue;
        case CURL_DO:
          tn->telrcv_state = CURL_TS_DO;
          continue;
        case CURL_DONT:
          tn->telrcv_state = CURL_TS_DONT;
          continue;
        case CURL_SB:
          CURL_SB_CLEAR(tn);
          tn->telrcv_state = CURL_TS_SB;
          continue;
        case CURL_IAC:
          Curl_client_write(data, CLIENTWRITE_BODY, (char *)&c, 1);
          break;
        case CURL_DM:
        case CURL_NOP:
        case CURL_GA:
        default:
          printoption(data, "RCVD", CURL_IAC, c);
          break;
      }
      tn->telrcv_state = CURL_TS_DATA;
      continue;

      case CURL_TS_WILL:
        printoption(data, "RCVD", CURL_WILL, c);
        tn->please_negotiate = 1;
        rec_will(conn, c);
        tn->telrcv_state = CURL_TS_DATA;
        continue;
      
      case CURL_TS_WONT:
        printoption(data, "RCVD", CURL_WONT, c);
        tn->please_negotiate = 1;
        rec_wont(conn, c);
        tn->telrcv_state = CURL_TS_DATA;
        continue;
      
      case CURL_TS_DO:
        printoption(data, "RCVD", CURL_DO, c);
        tn->please_negotiate = 1;
        rec_do(conn, c);
        tn->telrcv_state = CURL_TS_DATA;
        continue;
      
      case CURL_TS_DONT:
        printoption(data, "RCVD", CURL_DONT, c);
        tn->please_negotiate = 1;
        rec_dont(conn, c);
        tn->telrcv_state = CURL_TS_DATA;
        continue;

      case CURL_TS_SB:
        if (c == CURL_IAC)
        {
          tn->telrcv_state = CURL_TS_SE;
        }
        else
        {
          CURL_SB_ACCUM(tn,c);
        }
        continue;

      case CURL_TS_SE:
        if (c != CURL_SE)
        {
          if (c != CURL_IAC)
          {
            /*
             * This is an error.  We only expect to get
             * "IAC IAC" or "IAC SE".  Several things may
             * have happend.  An IAC was not doubled, the
             * IAC SE was left off, or another option got
             * inserted into the suboption are all possibilities.
             * If we assume that the IAC was not doubled,
             * and really the IAC SE was left off, we could
             * get into an infinate loop here.  So, instead,
             * we terminate the suboption, and process the
             * partial suboption if we can.
             */
            CURL_SB_ACCUM(tn, (unsigned char)CURL_IAC);
            CURL_SB_ACCUM(tn, c);
            tn->subpointer -= 2;
            CURL_SB_TERM(tn);
	    
            printoption(data, "In SUBOPTION processing, RCVD", CURL_IAC, c);
            suboption(conn);   /* handle sub-option */
            tn->telrcv_state = CURL_TS_IAC;
            goto process_iac;
          }
          CURL_SB_ACCUM(tn,c);
          tn->telrcv_state = CURL_TS_SB;
        }
        else
        {
          CURL_SB_ACCUM(tn, (unsigned char)CURL_IAC);
          CURL_SB_ACCUM(tn, (unsigned char)CURL_SE);
          tn->subpointer -= 2;
          CURL_SB_TERM(tn);
          suboption(conn);   /* handle sub-option */
          tn->telrcv_state = CURL_TS_DATA;
        }
        break;
    }
  }
}

CURLcode Curl_telnet_done(struct connectdata *conn)
{
  struct TELNET *tn = (struct TELNET *)conn->proto.telnet;
  curl_slist_free_all(tn->telnet_vars);

  free(conn->proto.telnet);
  conn->proto.telnet = NULL;

  return CURLE_OK;
}

CURLcode Curl_telnet(struct connectdata *conn)
{
  CURLcode code;
  struct SessionHandle *data = conn->data;
  int sockfd = conn->firstsocket;
#ifdef WIN32
  WSAEVENT event_handle;
  WSANETWORKEVENTS events;
  HANDLE stdin_handle;
  HANDLE objs[2];
  DWORD waitret;
#else
  fd_set readfd;
  fd_set keepfd;
#endif
  bool keepon = TRUE;
  char *buf = data->state.buffer;
  ssize_t nread;
  struct TELNET *tn;

  code = init_telnet(conn);
  if(code)
    return code;

  tn = (struct TELNET *)conn->proto.telnet;

  code = check_telnet_options(conn);
  if(code)
    return code;

#ifdef WIN32
  /* We want to wait for both stdin and the socket. Since
  ** the select() function in winsock only works on sockets
  ** we have to use the WaitForMultipleObjects() call.
  */

  /* First, create a sockets event object */
  event_handle = WSACreateEvent();

  /* The get the Windows file handle for stdin */
  stdin_handle = GetStdHandle(STD_INPUT_HANDLE);

  /* Create the list of objects to wait for */
  objs[0] = stdin_handle;
  objs[1] = event_handle;

  /* Tell winsock what events we want to listen to */
  if(WSAEventSelect(sockfd, event_handle, FD_READ|FD_CLOSE) == SOCKET_ERROR) {
    return 0;
  }

  /* Keep on listening and act on events */
  while(keepon) {
    waitret = WaitForMultipleObjects(2, objs, FALSE, INFINITE);
    switch(waitret - WAIT_OBJECT_0)
    {
      case 0:
      {
        unsigned char outbuf[2];
        int out_count = 0;
        ssize_t bytes_written;
        char *buffer = buf;
              
        if(!ReadFile(stdin_handle, buf, 255, (LPDWORD)&nread, NULL)) {
          keepon = FALSE;
          break;
        }
        
        while(nread--) {
          outbuf[0] = *buffer++;
          out_count = 1;
          if(outbuf[0] == CURL_IAC)
            outbuf[out_count++] = CURL_IAC;
          
          Curl_write(conn, conn->firstsocket, outbuf,
                     out_count, &bytes_written);
        }
      }
      break;
      
      case 1:
        if(WSAEnumNetworkEvents(sockfd, event_handle, &events)
           != SOCKET_ERROR)
        {
          if(events.lNetworkEvents & FD_READ)
          {
            /* This reallu OUGHT to check its return code. */
            Curl_read(conn, sockfd, buf, BUFSIZE - 1, &nread);
            
            telrcv(conn, (unsigned char *)buf, nread);
            
            fflush(stdout);
            
            /* Negotiate if the peer has started negotiating,
               otherwise don't. We don't want to speak telnet with
               non-telnet servers, like POP or SMTP. */
            if(tn->please_negotiate && !tn->already_negotiated) {
              negotiate(conn);
              tn->already_negotiated = 1;
            }
          }
          
          if(events.lNetworkEvents & FD_CLOSE)
          {
            keepon = FALSE;
          }
        }
        break;
    }
  }
#else
  FD_ZERO (&readfd);		/* clear it */
  FD_SET (sockfd, &readfd);
  FD_SET (0, &readfd);

  keepfd = readfd;

  while (keepon) {
    struct timeval interval;

    readfd = keepfd;		/* set this every lap in the loop */
    interval.tv_sec = 1;
    interval.tv_usec = 0;

    switch (select (sockfd + 1, &readfd, NULL, NULL, &interval)) {
    case -1:			/* error, stop reading */
      keepon = FALSE;
      continue;
    case 0:			/* timeout */
      break;
    default:			/* read! */
      if(FD_ISSET(0, &readfd)) { /* read from stdin */
        unsigned char outbuf[2];
        int out_count = 0;
        ssize_t bytes_written;
        char *buffer = buf;
        
        nread = read(0, buf, 255);

        while(nread--) {
          outbuf[0] = *buffer++;
          out_count = 1;
          if(outbuf[0] == CURL_IAC)
            outbuf[out_count++] = CURL_IAC;
      
          Curl_write(conn, conn->firstsocket, outbuf,
                     out_count, &bytes_written);
        }
      }

      if(FD_ISSET(sockfd, &readfd)) {
        /* This OUGHT to check the return code... */
        Curl_read(conn, sockfd, buf, BUFSIZE - 1, &nread);

        /* if we receive 0 or less here, the server closed the connection and
           we bail out from this! */
        if (nread <= 0) {
          keepon = FALSE;
          break;
        }

        telrcv(conn, (unsigned char *)buf, nread);

        /* Negotiate if the peer has started negotiating,
           otherwise don't. We don't want to speak telnet with
           non-telnet servers, like POP or SMTP. */
        if(tn->please_negotiate && !tn->already_negotiated) {
          negotiate(conn);
          tn->already_negotiated = 1;
        }
      }
    }
    if(data->set.timeout) {
      struct timeval now;           /* current time */
      now = Curl_tvnow();
      if(Curl_tvdiff(now, conn->created)/1000 >= data->set.timeout) {
        failf(data, "Time-out");
        code = CURLE_OPERATION_TIMEOUTED;
        keepon = FALSE;
      }
    }
  }
#endif
  /* mark this as "no further transfer wanted" */
  Curl_Transfer(conn, -1, -1, FALSE, NULL, -1, NULL);

  return code;
}
#endif