/*

 * Common run loop APIs for CUPS backends.

 *

 * Copyright 2007-2014 by Apple Inc.

 * Copyright 2006-2007 by Easy Software Products, all rights reserved.

 *

 * These coded instructions, statements, and computer programs are the

 * property of Apple Inc. and are protected by Federal copyright

 * law.  Distribution and use rights are outlined in the file "LICENSE.txt"

 * "LICENSE" which should have been included with this file.  If this

 * file is missing or damaged, see the license at "http://www.cups.org/".

 *

 * This file is subject to the Apple OS-Developed Software exception.

 */

/*

 * Include necessary headers.

 */

#include "backend-private.h"

#include <limits.h>

#include <sys/select.h>

/*

 * 'backendDrainOutput()' - Drain pending print data to the device.

 */

int					/* O - 0 on success, -1 on error */

backendDrainOutput(int print_fd,	/* I - Print file descriptor */

                   int device_fd)	/* I - Device file descriptor */

{

  int		nfds;			/* Maximum file descriptor value + 1 */

  fd_set	input;			/* Input set for reading */

  ssize_t	print_bytes,		/* Print bytes read */

		bytes;			/* Bytes written */

  char		print_buffer[8192],	/* Print data buffer */

		*print_ptr;		/* Pointer into print data buffer */

  struct timeval timeout;		/* Timeout for read... */

  fprintf(stderr, "DEBUG: backendDrainOutput(print_fd=%d, device_fd=%d)\n",

          print_fd, device_fd);

 /*

  * Figure out the maximum file descriptor value to use with select()...

  */

  nfds = (print_fd > device_fd ? print_fd : device_fd) + 1;

 /*

  * Now loop until we are out of data from print_fd...

  */

  for (;;)

  {

   /*

    * Use select() to determine whether we have data to copy around...

    */

    FD_ZERO(&input);

    FD_SET(print_fd, &input);

    timeout.tv_sec  = 0;

    timeout.tv_usec = 0;

    if (select(nfds, &input, NULL, NULL, &timeout) < 0)

      return (-1);

    if (!FD_ISSET(print_fd, &input))

      return (0);

    if ((print_bytes = read(print_fd, print_buffer,

			    sizeof(print_buffer))) < 0)

    {

     /*

      * Read error - bail if we don't see EAGAIN or EINTR...

      */

      if (errno != EAGAIN && errno != EINTR)

      {

	fprintf(stderr, "DEBUG: Read failed: %s\n", strerror(errno));

	_cupsLangPrintFilter(stderr, "ERROR", _("Unable to read print data."));

	return (-1);

      }

      print_bytes = 0;

    }

    else if (print_bytes == 0)

    {

     /*

      * End of file, return...

      */

      return (0);

    }

    fprintf(stderr, "DEBUG: Read %d bytes of print data...\n",

	    (int)print_bytes);

    for (print_ptr = print_buffer; print_bytes > 0;)

    {

      if ((bytes = write(device_fd, print_ptr, (size_t)print_bytes)) < 0)

      {

       /*

        * Write error - bail if we don't see an error we can retry...

	*/

        if (errno != ENOSPC && errno != ENXIO && errno != EAGAIN &&

	    errno != EINTR && errno != ENOTTY)

	{

	  _cupsLangPrintError("ERROR", _("Unable to write print data"));

	  return (-1);

	}

      }

      else

      {

        fprintf(stderr, "DEBUG: Wrote %d bytes of print data...\n", (int)bytes);

        print_bytes -= bytes;

	print_ptr   += bytes;

      }

    }

  }

}

/*

 * 'backendRunLoop()' - Read and write print and back-channel data.

 */

ssize_t					/* O - Total bytes on success, -1 on error */

backendRunLoop(

    int          print_fd,		/* I - Print file descriptor */

    int          device_fd,		/* I - Device file descriptor */

    int          snmp_fd,		/* I - SNMP socket or -1 if none */

    http_addr_t  *addr,			/* I - Address of device */

    int          use_bc,		/* I - Use back-channel? */

    int          update_state,		/* I - Update printer-state-reasons? */

    _cups_sccb_t side_cb)		/* I - Side-channel callback */

{

  int		nfds;			/* Maximum file descriptor value + 1 */

  fd_set	input,			/* Input set for reading */

		output;			/* Output set for writing */

  ssize_t	print_bytes,		/* Print bytes read */

		bc_bytes,		/* Backchannel bytes read */

		total_bytes,		/* Total bytes written */

		bytes;			/* Bytes written */

  int		paperout;		/* "Paper out" status */

  int		offline;		/* "Off-line" status */

  char		print_buffer[8192],	/* Print data buffer */

		*print_ptr,		/* Pointer into print data buffer */

		bc_buffer[1024];	/* Back-channel data buffer */

  struct timeval timeout;		/* Timeout for select() */

  time_t	curtime,		/* Current time */

		snmp_update = 0;

#if defined(HAVE_SIGACTION) && !defined(HAVE_SIGSET)

  struct sigaction action;		/* Actions for POSIX signals */

#endif /* HAVE_SIGACTION && !HAVE_SIGSET */

  fprintf(stderr,

          "DEBUG: backendRunLoop(print_fd=%d, device_fd=%d, snmp_fd=%d, "

	  "addr=%p, use_bc=%d, side_cb=%p)\n",

          print_fd, device_fd, snmp_fd, addr, use_bc, side_cb);

 /*

  * If we are printing data from a print driver on stdin, ignore SIGTERM

  * so that the driver can finish out any page data, e.g. to eject the

  * current page.  We only do this for stdin printing as otherwise there

  * is no way to cancel a raw print job...

  */

  if (!print_fd)

  {

#ifdef HAVE_SIGSET /* Use System V signals over POSIX to avoid bugs */

    sigset(SIGTERM, SIG_IGN);

#elif defined(HAVE_SIGACTION)

    memset(&action, 0, sizeof(action));

    sigemptyset(&action.sa_mask);

    action.sa_handler = SIG_IGN;

    sigaction(SIGTERM, &action, NULL);

#else

    signal(SIGTERM, SIG_IGN);

#endif /* HAVE_SIGSET */

  }

  else if (print_fd < 0)

  {

   /*

    * Copy print data from stdin, but don't mess with the signal handlers...

    */

    print_fd = 0;

  }

 /*

  * Figure out the maximum file descriptor value to use with select()...

  */

  nfds = (print_fd > device_fd ? print_fd : device_fd) + 1;

 /*

  * Now loop until we are out of data from print_fd...

  */

  for (print_bytes = 0, print_ptr = print_buffer, offline = -1,

           paperout = -1, total_bytes = 0;;)

  {

   /*

    * Use select() to determine whether we have data to copy around...

    */

    FD_ZERO(&input);

    if (!print_bytes)

      FD_SET(print_fd, &input);

    if (use_bc)

      FD_SET(device_fd, &input);

    if (!print_bytes && side_cb)

      FD_SET(CUPS_SC_FD, &input);

    FD_ZERO(&output);

    if (print_bytes || (!use_bc && !side_cb))

      FD_SET(device_fd, &output);

    if (use_bc || side_cb)

    {

      timeout.tv_sec  = 5;

      timeout.tv_usec = 0;

      if (select(nfds, &input, &output, NULL, &timeout) < 0)

      {

       /*

	* Pause printing to clear any pending errors...

	*/

	if (errno == ENXIO && offline != 1 && update_state)

	{

	  fputs("STATE: +offline-report\n", stderr);

	  _cupsLangPrintFilter(stderr, "INFO",

	                       _("The printer is not connected."));

	  offline = 1;

	}

	else if (errno == EINTR && total_bytes == 0)

	{

	  fputs("DEBUG: Received an interrupt before any bytes were "

	        "written, aborting.\n", stderr);

          return (0);

	}

	sleep(1);

	continue;

      }

    }

   /*

    * Check if we have a side-channel request ready...

    */

    if (side_cb && FD_ISSET(CUPS_SC_FD, &input))

    {

     /*

      * Do the side-channel request, then start back over in the select

      * loop since it may have read from print_fd...

      */

      if ((*side_cb)(print_fd, device_fd, snmp_fd, addr, use_bc))

        side_cb = NULL;

      continue;

    }

   /*

    * Check if we have back-channel data ready...

    */

    if (FD_ISSET(device_fd, &input))

    {

      if ((bc_bytes = read(device_fd, bc_buffer, sizeof(bc_buffer))) > 0)

      {

	fprintf(stderr,

	        "DEBUG: Received " CUPS_LLFMT " bytes of back-channel data\n",

	        CUPS_LLCAST bc_bytes);

        cupsBackChannelWrite(bc_buffer, (size_t)bc_bytes, 1.0);

      }

      else if (bc_bytes < 0 && errno != EAGAIN && errno != EINTR)

      {

        fprintf(stderr, "DEBUG: Error reading back-channel data: %s\n",

	        strerror(errno));

	use_bc = 0;

      }

      else if (bc_bytes == 0)

        use_bc = 0;

    }

   /*

    * Check if we have print data ready...

    */

    if (FD_ISSET(print_fd, &input))

    {

      if ((print_bytes = read(print_fd, print_buffer,

                              sizeof(print_buffer))) < 0)

      {

       /*

        * Read error - bail if we don't see EAGAIN or EINTR...

	*/

	if (errno != EAGAIN && errno != EINTR)

	{

	  fprintf(stderr, "DEBUG: Read failed: %s\n", strerror(errno));

	  _cupsLangPrintFilter(stderr, "ERROR",

	                       _("Unable to read print data."));

	  return (-1);

	}

        print_bytes = 0;

      }

      else if (print_bytes == 0)

      {

       /*

        * End of file, break out of the loop...

	*/

        break;

      }

      print_ptr = print_buffer;

      fprintf(stderr, "DEBUG: Read %d bytes of print data...\n",

              (int)print_bytes);

    }

   /*

    * Check if the device is ready to receive data and we have data to

    * send...

    */

    if (print_bytes && FD_ISSET(device_fd, &output))

    {

      if ((bytes = write(device_fd, print_ptr, (size_t)print_bytes)) < 0)

      {

       /*

        * Write error - bail if we don't see an error we can retry...

	*/

        if (errno == ENOSPC)

	{

	  if (paperout != 1 && update_state)

	  {

	    fputs("STATE: +media-empty-warning\n", stderr);

	    fputs("DEBUG: Out of paper\n", stderr);

	    paperout = 1;

	  }

        }

	else if (errno == ENXIO)

	{

	  if (offline != 1 && update_state)

	  {

	    fputs("STATE: +offline-report\n", stderr);

	    _cupsLangPrintFilter(stderr, "INFO",

	                         _("The printer is not connected."));

	    offline = 1;

	  }

	}

	else if (errno != EAGAIN && errno != EINTR && errno != ENOTTY)

	{

	  _cupsLangPrintError("ERROR", _("Unable to write print data"));

	  return (-1);

	}

      }

      else

      {

        if (paperout && update_state)

	{

	  fputs("STATE: -media-empty-warning\n", stderr);

	  paperout = 0;

	}

	if (offline && update_state)

	{

	  fputs("STATE: -offline-report\n", stderr);

	  _cupsLangPrintFilter(stderr, "INFO",

	                       _("The printer is now connected."));

	  offline = 0;

	}

        fprintf(stderr, "DEBUG: Wrote %d bytes of print data...\n", (int)bytes);

        print_bytes -= bytes;

	print_ptr   += bytes;

	total_bytes += bytes;

      }

    }

   /*

    * Do SNMP updates periodically...

    */

    if (snmp_fd >= 0 && time(&curtime) >= snmp_update)

    {

      if (backendSNMPSupplies(snmp_fd, addr, NULL, NULL))

        snmp_update = INT_MAX;

      else

        snmp_update = curtime + 5;

    }

  }

 /*

  * Return with success...

  */

  return (total_bytes);

}

/*

 * 'backendWaitLoop()' - Wait for input from stdin while handling side-channel

 *                       queries.

 */

int					/* O - 1 if data is ready, 0 if not */

backendWaitLoop(

    int          snmp_fd,		/* I - SNMP socket or -1 if none */

    http_addr_t  *addr,			/* I - Address of device */

    int          use_bc,		/* I - Use back-channel? */

    _cups_sccb_t side_cb)		/* I - Side-channel callback */

{

  int			nfds;		/* Number of file descriptors */

  fd_set		input;		/* Input set for reading */

  time_t		curtime = 0,	/* Current time */

			snmp_update = 0;/* Last SNMP status update */

  struct timeval	timeout;	/* Timeout for select() */

  fprintf(stderr, "DEBUG: backendWaitLoop(snmp_fd=%d, addr=%p, side_cb=%p)\n",

	  snmp_fd, addr, side_cb);

 /*

  * Now loop until we receive data from stdin...

  */

  if (snmp_fd >= 0)

    snmp_update = time(NULL) + 5;

  for (;;)

  {

   /*

    * Use select() to determine whether we have data to copy around...

    */

    FD_ZERO(&input);

    FD_SET(0, &input);

    if (side_cb)

      FD_SET(CUPS_SC_FD, &input);

    if (snmp_fd >= 0)

    {

      curtime         = time(NULL);

      timeout.tv_sec  = curtime >= snmp_update ? 0 : snmp_update - curtime;

      timeout.tv_usec = 0;

      nfds = select(CUPS_SC_FD + 1, &input, NULL, NULL, &timeout);

    }

    else

      nfds = select(CUPS_SC_FD + 1, &input, NULL, NULL, NULL);

    if (nfds < 0)

    {

     /*

      * Pause printing to clear any pending errors...

      */

      if (errno == EINTR)

      {

	fputs("DEBUG: Received an interrupt before any bytes were "

	      "written, aborting.\n", stderr);

	return (0);

      }

      sleep(1);

      continue;

    }

   /*

    * Check for input on stdin...

    */

    if (FD_ISSET(0, &input))

      break;

   /*

    * Check if we have a side-channel request ready...

    */

    if (side_cb && FD_ISSET(CUPS_SC_FD, &input))

    {

     /*

      * Do the side-channel request, then start back over in the select

      * loop since it may have read from print_fd...

      */

      if ((*side_cb)(0, -1, snmp_fd, addr, use_bc))

        side_cb = NULL;

      continue;

    }

   /*

    * Do SNMP updates periodically...

    */

    if (snmp_fd >= 0 && curtime >= snmp_update)

    {

      if (backendSNMPSupplies(snmp_fd, addr, NULL, NULL))

        snmp_fd = -1;

      else

        snmp_update = curtime + 5;

    }

  }

 /*

  * Return with success...

  */

  return (1);

}