[thirdparty/cups.git] / backend / runloop.c

/*
 * 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);
}
Commit	Line	Data
ed486911	1	/*
5a1d7a17	2	* Common run loop APIs for CUPS backends.
ed486911	3	*
7e86f2f6	4	* Copyright 2007-2014 by Apple Inc.
5a1d7a17	5	* Copyright 2006-2007 by Easy Software Products, all rights reserved.
ed486911	6	*
5a1d7a17 MS	7	* These coded instructions, statements, and computer programs are the
	8	* property of Apple Inc. and are protected by Federal copyright
	9	* law. Distribution and use rights are outlined in the file "LICENSE.txt"
	10	* "LICENSE" which should have been included with this file. If this
	11	* file is missing or damaged, see the license at "http://www.cups.org/".
ed486911	12	*
5a1d7a17	13	* This file is subject to the Apple OS-Developed Software exception.
ed486911	14	*/
	15
	16	/*
	17	* Include necessary headers.
	18	*/
	19
	20	#include "backend-private.h"
568fa3fa	21	#include <limits.h>
5a1d7a17	22	#include <sys/select.h>
ed486911	23
ed486911	24
09a101d6	25	/*
	26	* 'backendDrainOutput()' - Drain pending print data to the device.
	27	*/
	28
	29	int /* O - 0 on success, -1 on error */
	30	backendDrainOutput(int print_fd, /* I - Print file descriptor */
	31	int device_fd) /* I - Device file descriptor */
	32	{
	33	int nfds; /* Maximum file descriptor value + 1 */
	34	fd_set input; /* Input set for reading */
	35	ssize_t print_bytes, /* Print bytes read */
	36	bytes; /* Bytes written */
	37	char print_buffer[8192], /* Print data buffer */
	38	print_ptr; / Pointer into print data buffer */
	39	struct timeval timeout; /* Timeout for read... */
	40
	41
	42	fprintf(stderr, "DEBUG: backendDrainOutput(print_fd=%d, device_fd=%d)\n",
	43	print_fd, device_fd);
	44
	45	/*
	46	* Figure out the maximum file descriptor value to use with select()...
	47	*/
	48
	49	nfds = (print_fd > device_fd ? print_fd : device_fd) + 1;
	50
	51	/*
	52	* Now loop until we are out of data from print_fd...
	53	*/
	54
	55	for (;;)
	56	{
	57	/*
	58	* Use select() to determine whether we have data to copy around...
	59	*/
	60
	61	FD_ZERO(&input);
	62	FD_SET(print_fd, &input);
	63
	64	timeout.tv_sec = 0;
	65	timeout.tv_usec = 0;
	66
	67	if (select(nfds, &input, NULL, NULL, &timeout) < 0)
	68	return (-1);
	69
	70	if (!FD_ISSET(print_fd, &input))
	71	return (0);
	72
	73	if ((print_bytes = read(print_fd, print_buffer,
	74	sizeof(print_buffer))) < 0)
	75	{
	76	/*
	77	* Read error - bail if we don't see EAGAIN or EINTR...
	78	*/
	79
	80	if (errno != EAGAIN \|\| errno != EINTR)
	81	{
f3c17241 MS	82	fprintf(stderr, "DEBUG: Read failed: %s\n", strerror(errno));
f3c17241 MS	83	_cupsLangPrintFilter(stderr, "ERROR", _("Unable to read print data."));
09a101d6	84	return (-1);
	85	}
	86
	87	print_bytes = 0;
	88	}
	89	else if (print_bytes == 0)
	90	{
	91	/*
	92	* End of file, return...
	93	*/
	94
	95	return (0);
	96	}
	97
	98	fprintf(stderr, "DEBUG: Read %d bytes of print data...\n",
	99	(int)print_bytes);
	100
	101	for (print_ptr = print_buffer; print_bytes > 0;)
	102	{
7e86f2f6	103	if ((bytes = write(device_fd, print_ptr, (size_t)print_bytes)) < 0)
09a101d6	104	{
	105	/*
	106	* Write error - bail if we don't see an error we can retry...
	107	*/
	108
	109	if (errno != ENOSPC && errno != ENXIO && errno != EAGAIN &&
	110	errno != EINTR && errno != ENOTTY)
	111	{
0837b7e8	112	_cupsLangPrintError("ERROR", _("Unable to write print data"));
09a101d6	113	return (-1);
	114	}
	115	}
	116	else
	117	{
	118	fprintf(stderr, "DEBUG: Wrote %d bytes of print data...\n", (int)bytes);
	119
	120	print_bytes -= bytes;
	121	print_ptr += bytes;
	122	}
	123	}
	124	}
	125	}
	126
	127
ed486911	128	/*
	129	* 'backendRunLoop()' - Read and write print and back-channel data.
	130	*/
	131
	132	ssize_t /* O - Total bytes on success, -1 on error */
f7deaa1a	133	backendRunLoop(
c8fef167 MS	134	int print_fd, /* I - Print file descriptor */
	135	int device_fd, /* I - Device file descriptor */
	136	int snmp_fd, /* I - SNMP socket or -1 if none */
	137	http_addr_t addr, / I - Address of device */
	138	int use_bc, /* I - Use back-channel? */
	139	int update_state, /* I - Update printer-state-reasons? */
	140	_cups_sccb_t side_cb) /* I - Side-channel callback */
ed486911	141	{
	142	int nfds; /* Maximum file descriptor value + 1 */
	143	fd_set input, /* Input set for reading */
	144	output; /* Output set for writing */
	145	ssize_t print_bytes, /* Print bytes read */
	146	bc_bytes, /* Backchannel bytes read */
	147	total_bytes, /* Total bytes written */
	148	bytes; /* Bytes written */
	149	int paperout; /* "Paper out" status */
8ca02f3c	150	int offline; /* "Off-line" status */
ed486911	151	char print_buffer[8192], /* Print data buffer */
	152	print_ptr, / Pointer into print data buffer */
	153	bc_buffer[1024]; /* Back-channel data buffer */
568fa3fa MS	154	struct timeval timeout; /* Timeout for select() */
	155	time_t curtime, /* Current time */
	156	snmp_update = 0;
ed486911	157	#if defined(HAVE_SIGACTION) && !defined(HAVE_SIGSET)
	158	struct sigaction action; /* Actions for POSIX signals */
	159	#endif /* HAVE_SIGACTION && !HAVE_SIGSET */
	160
	161
c0e1af83	162	fprintf(stderr,
568fa3fa MS	163	"DEBUG: backendRunLoop(print_fd=%d, device_fd=%d, snmp_fd=%d, "
	164	"addr=%p, use_bc=%d, side_cb=%p)\n",
	165	print_fd, device_fd, snmp_fd, addr, use_bc, side_cb);
8ca02f3c	166
ed486911	167	/*
	168	* If we are printing data from a print driver on stdin, ignore SIGTERM
	169	* so that the driver can finish out any page data, e.g. to eject the
	170	* current page. We only do this for stdin printing as otherwise there
	171	* is no way to cancel a raw print job...
	172	*/
	173
	174	if (!print_fd)
	175	{
	176	#ifdef HAVE_SIGSET /* Use System V signals over POSIX to avoid bugs */
	177	sigset(SIGTERM, SIG_IGN);
	178	#elif defined(HAVE_SIGACTION)
	179	memset(&action, 0, sizeof(action));
	180
	181	sigemptyset(&action.sa_mask);
	182	action.sa_handler = SIG_IGN;
	183	sigaction(SIGTERM, &action, NULL);
	184	#else
	185	signal(SIGTERM, SIG_IGN);
	186	#endif /* HAVE_SIGSET */
	187	}
4e6f60f0 MS	188	else if (print_fd < 0)
	189	{
	190	/*
	191	* Copy print data from stdin, but don't mess with the signal handlers...
	192	*/
	193
	194	print_fd = 0;
	195	}
ed486911	196
	197	/*
	198	* Figure out the maximum file descriptor value to use with select()...
	199	*/
	200
	201	nfds = (print_fd > device_fd ? print_fd : device_fd) + 1;
	202
	203	/*
	204	* Now loop until we are out of data from print_fd...
	205	*/
	206
b94498cf	207	for (print_bytes = 0, print_ptr = print_buffer, offline = -1,
b94498cf	208	paperout = -1, total_bytes = 0;;)
ed486911	209	{
	210	/*
	211	* Use select() to determine whether we have data to copy around...
	212	*/
	213
	214	FD_ZERO(&input);
	215	if (!print_bytes)
	216	FD_SET(print_fd, &input);
	217	if (use_bc)
	218	FD_SET(device_fd, &input);
dd1abb6b	219	if (!print_bytes && side_cb)
f7deaa1a	220	FD_SET(CUPS_SC_FD, &input);
ed486911	221
ed486911	222	FD_ZERO(&output);
91c84a35	223	if (print_bytes \|\| (!use_bc && !side_cb))
ed486911	224	FD_SET(device_fd, &output);
ed486911	225
f7deaa1a	226	if (use_bc \|\| side_cb)
8ca02f3c	227	{
568fa3fa MS	228	timeout.tv_sec = 5;
	229	timeout.tv_usec = 0;
	230
	231	if (select(nfds, &input, &output, NULL, &timeout) < 0)
8ca02f3c	232	{
	233	/*
	234	* Pause printing to clear any pending errors...
	235	*/
	236
ef55b745	237	if (errno == ENXIO && offline != 1 && update_state)
8ca02f3c	238	{
c5571a1d	239	fputs("STATE: +offline-report\n", stderr);
0837b7e8	240	_cupsLangPrintFilter(stderr, "INFO",
f3c17241	241	_("The printer is not connected."));
8ca02f3c	242	offline = 1;
8ca02f3c	243	}
b94498cf	244	else if (errno == EINTR && total_bytes == 0)
	245	{
	246	fputs("DEBUG: Received an interrupt before any bytes were "
c8fef167	247	"written, aborting.\n", stderr);
b94498cf	248	return (0);
b94498cf	249	}
8ca02f3c	250
	251	sleep(1);
	252	continue;
	253	}
	254	}
ed486911	255
f7deaa1a	256	/*
	257	* Check if we have a side-channel request ready...
	258	*/
	259
	260	if (side_cb && FD_ISSET(CUPS_SC_FD, &input))
dd1abb6b MS	261	{
	262	/*
	263	* Do the side-channel request, then start back over in the select
	264	* loop since it may have read from print_fd...
	265	*/
	266
18ecb428 MS	267	if ((*side_cb)(print_fd, device_fd, snmp_fd, addr, use_bc))
18ecb428 MS	268	side_cb = NULL;
dd1abb6b MS	269	continue;
dd1abb6b MS	270	}
f7deaa1a	271
ed486911	272	/*
	273	* Check if we have back-channel data ready...
	274	*/
	275
	276	if (FD_ISSET(device_fd, &input))
	277	{
	278	if ((bc_bytes = read(device_fd, bc_buffer, sizeof(bc_buffer))) > 0)
	279	{
	280	fprintf(stderr,
4d301e69	281	"DEBUG: Received " CUPS_LLFMT " bytes of back-channel data\n",
ed486911	282	CUPS_LLCAST bc_bytes);
7e86f2f6	283	cupsBackChannelWrite(bc_buffer, (size_t)bc_bytes, 1.0);
ed486911	284	}
4b3f67ff MS	285	else if (bc_bytes < 0 && errno != EAGAIN && errno != EINTR)
	286	{
	287	fprintf(stderr, "DEBUG: Error reading back-channel data: %s\n",
	288	strerror(errno));
	289	use_bc = 0;
	290	}
7cf5915e MS	291	else if (bc_bytes == 0)
7cf5915e MS	292	use_bc = 0;
ed486911	293	}
	294
	295	/*
	296	* Check if we have print data ready...
	297	*/
	298
	299	if (FD_ISSET(print_fd, &input))
	300	{
	301	if ((print_bytes = read(print_fd, print_buffer,
	302	sizeof(print_buffer))) < 0)
	303	{
	304	/*
	305	* Read error - bail if we don't see EAGAIN or EINTR...
	306	*/
	307
	308	if (errno != EAGAIN \|\| errno != EINTR)
	309	{
f3c17241 MS	310	fprintf(stderr, "DEBUG: Read failed: %s\n", strerror(errno));
	311	_cupsLangPrintFilter(stderr, "ERROR",
	312	_("Unable to read print data."));
ed486911	313	return (-1);
	314	}
	315
	316	print_bytes = 0;
	317	}
	318	else if (print_bytes == 0)
	319	{
	320	/*
	321	* End of file, break out of the loop...
	322	*/
	323
	324	break;
	325	}
	326
	327	print_ptr = print_buffer;
8ca02f3c	328
	329	fprintf(stderr, "DEBUG: Read %d bytes of print data...\n",
	330	(int)print_bytes);
ed486911	331	}
	332
	333	/*
	334	* Check if the device is ready to receive data and we have data to
	335	* send...
	336	*/
	337
	338	if (print_bytes && FD_ISSET(device_fd, &output))
	339	{
7e86f2f6	340	if ((bytes = write(device_fd, print_ptr, (size_t)print_bytes)) < 0)
ed486911	341	{
	342	/*
	343	* Write error - bail if we don't see an error we can retry...
	344	*/
	345
	346	if (errno == ENOSPC)
	347	{
ef55b745	348	if (paperout != 1 && update_state)
ed486911	349	{
c5571a1d	350	fputs("STATE: +media-empty-warning\n", stderr);
0837b7e8	351	fputs("DEBUG: Out of paper\n", stderr);
ed486911	352	paperout = 1;
	353	}
	354	}
8ca02f3c	355	else if (errno == ENXIO)
8ca02f3c	356	{
ef55b745	357	if (offline != 1 && update_state)
8ca02f3c	358	{
c5571a1d	359	fputs("STATE: +offline-report\n", stderr);
0837b7e8	360	_cupsLangPrintFilter(stderr, "INFO",
f3c17241	361	_("The printer is not connected."));
8ca02f3c	362	offline = 1;
	363	}
	364	}
ed486911	365	else if (errno != EAGAIN && errno != EINTR && errno != ENOTTY)
ed486911	366	{
0837b7e8	367	_cupsLangPrintError("ERROR", _("Unable to write print data"));
ed486911	368	return (-1);
	369	}
	370	}
	371	else
	372	{
ef55b745	373	if (paperout && update_state)
ed486911	374	{
c5571a1d	375	fputs("STATE: -media-empty-warning\n", stderr);
ed486911	376	paperout = 0;
	377	}
	378
ef55b745	379	if (offline && update_state)
8ca02f3c	380	{
c5571a1d	381	fputs("STATE: -offline-report\n", stderr);
f3c17241 MS	382	_cupsLangPrintFilter(stderr, "INFO",
f3c17241 MS	383	_("The printer is now connected."));
8ca02f3c	384	offline = 0;
	385	}
	386
	387	fprintf(stderr, "DEBUG: Wrote %d bytes of print data...\n", (int)bytes);
ed486911	388
	389	print_bytes -= bytes;
	390	print_ptr += bytes;
	391	total_bytes += bytes;
	392	}
	393	}
568fa3fa MS	394
	395	/*
	396	* Do SNMP updates periodically...
	397	*/
	398
	399	if (snmp_fd >= 0 && time(&curtime) >= snmp_update)
	400	{
	401	if (backendSNMPSupplies(snmp_fd, addr, NULL, NULL))
	402	snmp_update = INT_MAX;
	403	else
	404	snmp_update = curtime + 5;
	405	}
ed486911	406	}
	407
	408	/*
	409	* Return with success...
	410	*/
	411
	412	return (total_bytes);
	413	}
	414
	415
	416	/*
c8fef167 MS	417	* 'backendWaitLoop()' - Wait for input from stdin while handling side-channel
	418	* queries.
	419	*/
	420
	421	int /* O - 1 if data is ready, 0 if not */
	422	backendWaitLoop(
	423	int snmp_fd, /* I - SNMP socket or -1 if none */
	424	http_addr_t addr, / I - Address of device */
f14324a7	425	int use_bc, /* I - Use back-channel? */
c8fef167 MS	426	_cups_sccb_t side_cb) /* I - Side-channel callback */
c8fef167 MS	427	{
82cc1f9a MS	428	int nfds; /* Number of file descriptors */
	429	fd_set input; /* Input set for reading */
	430	time_t curtime = 0, /* Current time */
	431	snmp_update = 0;/* Last SNMP status update */
	432	struct timeval timeout; /* Timeout for select() */
c8fef167 MS	433
	434
	435	fprintf(stderr, "DEBUG: backendWaitLoop(snmp_fd=%d, addr=%p, side_cb=%p)\n",
	436	snmp_fd, addr, side_cb);
	437
	438	/*
	439	* Now loop until we receive data from stdin...
	440	*/
	441
82cc1f9a MS	442	if (snmp_fd >= 0)
	443	snmp_update = time(NULL) + 5;
	444
c8fef167 MS	445	for (;;)
	446	{
	447	/*
	448	* Use select() to determine whether we have data to copy around...
	449	*/
	450
	451	FD_ZERO(&input);
	452	FD_SET(0, &input);
	453	if (side_cb)
	454	FD_SET(CUPS_SC_FD, &input);
	455
82cc1f9a MS	456	if (snmp_fd >= 0)
	457	{
	458	curtime = time(NULL);
	459	timeout.tv_sec = curtime >= snmp_update ? 0 : snmp_update - curtime;
	460	timeout.tv_usec = 0;
	461
	462	nfds = select(CUPS_SC_FD + 1, &input, NULL, NULL, &timeout);
	463	}
	464	else
	465	nfds = select(CUPS_SC_FD + 1, &input, NULL, NULL, NULL);
	466
	467	if (nfds < 0)
c8fef167 MS	468	{
	469	/*
	470	* Pause printing to clear any pending errors...
	471	*/
	472
	473	if (errno == EINTR)
	474	{
	475	fputs("DEBUG: Received an interrupt before any bytes were "
	476	"written, aborting.\n", stderr);
	477	return (0);
	478	}
	479
	480	sleep(1);
	481	continue;
	482	}
	483
	484	/*
	485	* Check for input on stdin...
	486	*/
	487
	488	if (FD_ISSET(0, &input))
	489	break;
	490
	491	/*
	492	* Check if we have a side-channel request ready...
	493	*/
	494
	495	if (side_cb && FD_ISSET(CUPS_SC_FD, &input))
	496	{
	497	/*
	498	* Do the side-channel request, then start back over in the select
	499	* loop since it may have read from print_fd...
	500	*/
	501
f14324a7	502	if ((*side_cb)(0, -1, snmp_fd, addr, use_bc))
c8fef167 MS	503	side_cb = NULL;
	504	continue;
	505	}
	506
	507	/*
	508	* Do SNMP updates periodically...
	509	*/
	510
82cc1f9a	511	if (snmp_fd >= 0 && curtime >= snmp_update)
c8fef167 MS	512	{
c8fef167 MS	513	if (backendSNMPSupplies(snmp_fd, addr, NULL, NULL))
82cc1f9a	514	snmp_fd = -1;
c8fef167 MS	515	else
	516	snmp_update = curtime + 5;
	517	}
	518	}
	519
	520	/*
	521	* Return with success...
	522	*/
	523
	524	return (1);
	525	}