Function cupsSideChannelWrite

cups/sidechannel.c:519–617

 */

int					/* O - 0 on success, -1 on error */
cupsSideChannelWrite(
    cups_sc_command_t command,		/* I - Command code */
    cups_sc_status_t  status,		/* I - Status code */
    const char        *data,		/* I - Data buffer pointer */
    int               datalen,		/* I - Number of bytes of data */
    double            timeout)		/* I - Timeout in seconds */
{
  char		*buffer;		/* Message buffer */
  ssize_t	bytes;			/* Bytes written */
#ifdef HAVE_POLL
  struct pollfd	pfd;			/* Poll structure for poll() */
#else /* select() */
  fd_set	output_set;		/* Output set for select() */
  struct timeval stimeout;		/* Timeout value for select() */
#endif /* HAVE_POLL */


 /*
  * Range check input...
  */

  if (command < CUPS_SC_CMD_SOFT_RESET || command >= CUPS_SC_CMD_MAX ||
      datalen < 0 || datalen > _CUPS_SC_MAX_DATA || (datalen > 0 && !data))
    return (-1);

 /*
  * See if we can safely write to the side-channel socket...
  */

#ifdef HAVE_POLL
  pfd.fd     = CUPS_SC_FD;
  pfd.events = POLLOUT;

  if (timeout < 0.0)
  {
    if (poll(&pfd, 1, -1) < 1)
      return (-1);
  }
  else if (poll(&pfd, 1, (int)(timeout * 1000)) < 1)
    return (-1);

#else /* select() */
  FD_ZERO(&output_set);
  FD_SET(CUPS_SC_FD, &output_set);

  if (timeout < 0.0)
  {
    if (select(CUPS_SC_FD + 1, NULL, &output_set, NULL, NULL) < 1)
      return (-1);
  }
  else
  {
    stimeout.tv_sec  = (int)timeout;
    stimeout.tv_usec = (int)(timeout * 1000000) % 1000000;

    if (select(CUPS_SC_FD + 1, NULL, &output_set, NULL, &stimeout) < 1)
      return (-1);