[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.
 *
 * Licensed under Apache License v2.0.  See the file "LICENSE" for more
 * information.
 */

/*
 * 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	*
53f8d64f MS	4	* Copyright © 2007-2014 by Apple Inc.
53f8d64f MS	5	* Copyright © 2006-2007 by Easy Software Products, all rights reserved.
ed486911	6	*
53f8d64f MS	7	* Licensed under Apache License v2.0. See the file "LICENSE" for more
53f8d64f MS	8	* information.
ed486911	9	*/
	10
	11	/*
	12	* Include necessary headers.
	13	*/
	14
	15	#include "backend-private.h"
568fa3fa	16	#include <limits.h>
5a1d7a17	17	#include <sys/select.h>
ed486911	18
ed486911	19
09a101d6	20	/*
	21	* 'backendDrainOutput()' - Drain pending print data to the device.
	22	*/
	23
	24	int /* O - 0 on success, -1 on error */
	25	backendDrainOutput(int print_fd, /* I - Print file descriptor */
	26	int device_fd) /* I - Device file descriptor */
	27	{
	28	int nfds; /* Maximum file descriptor value + 1 */
	29	fd_set input; /* Input set for reading */
	30	ssize_t print_bytes, /* Print bytes read */
	31	bytes; /* Bytes written */
	32	char print_buffer[8192], /* Print data buffer */
	33	print_ptr; / Pointer into print data buffer */
	34	struct timeval timeout; /* Timeout for read... */
	35
	36
	37	fprintf(stderr, "DEBUG: backendDrainOutput(print_fd=%d, device_fd=%d)\n",
	38	print_fd, device_fd);
	39
	40	/*
	41	* Figure out the maximum file descriptor value to use with select()...
	42	*/
	43
	44	nfds = (print_fd > device_fd ? print_fd : device_fd) + 1;
	45
	46	/*
	47	* Now loop until we are out of data from print_fd...
	48	*/
	49
	50	for (;;)
	51	{
	52	/*
	53	* Use select() to determine whether we have data to copy around...
	54	*/
	55
	56	FD_ZERO(&input);
	57	FD_SET(print_fd, &input);
	58
	59	timeout.tv_sec = 0;
	60	timeout.tv_usec = 0;
	61
	62	if (select(nfds, &input, NULL, NULL, &timeout) < 0)
	63	return (-1);
	64
	65	if (!FD_ISSET(print_fd, &input))
	66	return (0);
	67
	68	if ((print_bytes = read(print_fd, print_buffer,
	69	sizeof(print_buffer))) < 0)
	70	{
	71	/*
	72	* Read error - bail if we don't see EAGAIN or EINTR...
	73	*/
	74
0b1399a2	75	if (errno != EAGAIN && errno != EINTR)
09a101d6	76	{
f3c17241 MS	77	fprintf(stderr, "DEBUG: Read failed: %s\n", strerror(errno));
f3c17241 MS	78	_cupsLangPrintFilter(stderr, "ERROR", _("Unable to read print data."));
09a101d6	79	return (-1);
	80	}
	81
	82	print_bytes = 0;
	83	}
	84	else if (print_bytes == 0)
	85	{
	86	/*
	87	* End of file, return...
	88	*/
	89
	90	return (0);
	91	}
	92
	93	fprintf(stderr, "DEBUG: Read %d bytes of print data...\n",
	94	(int)print_bytes);
	95
	96	for (print_ptr = print_buffer; print_bytes > 0;)
	97	{
7e86f2f6	98	if ((bytes = write(device_fd, print_ptr, (size_t)print_bytes)) < 0)
09a101d6	99	{
	100	/*
	101	* Write error - bail if we don't see an error we can retry...
	102	*/
	103
	104	if (errno != ENOSPC && errno != ENXIO && errno != EAGAIN &&
	105	errno != EINTR && errno != ENOTTY)
	106	{
0837b7e8	107	_cupsLangPrintError("ERROR", _("Unable to write print data"));
09a101d6	108	return (-1);
	109	}
	110	}
	111	else
	112	{
	113	fprintf(stderr, "DEBUG: Wrote %d bytes of print data...\n", (int)bytes);
	114
	115	print_bytes -= bytes;
	116	print_ptr += bytes;
	117	}
	118	}
	119	}
	120	}
	121
	122
ed486911	123	/*
	124	* 'backendRunLoop()' - Read and write print and back-channel data.
	125	*/
	126
	127	ssize_t /* O - Total bytes on success, -1 on error */
f7deaa1a	128	backendRunLoop(
c8fef167 MS	129	int print_fd, /* I - Print file descriptor */
	130	int device_fd, /* I - Device file descriptor */
	131	int snmp_fd, /* I - SNMP socket or -1 if none */
	132	http_addr_t addr, / I - Address of device */
	133	int use_bc, /* I - Use back-channel? */
	134	int update_state, /* I - Update printer-state-reasons? */
	135	_cups_sccb_t side_cb) /* I - Side-channel callback */
ed486911	136	{
	137	int nfds; /* Maximum file descriptor value + 1 */
	138	fd_set input, /* Input set for reading */
	139	output; /* Output set for writing */
	140	ssize_t print_bytes, /* Print bytes read */
	141	bc_bytes, /* Backchannel bytes read */
	142	total_bytes, /* Total bytes written */
	143	bytes; /* Bytes written */
	144	int paperout; /* "Paper out" status */
8ca02f3c	145	int offline; /* "Off-line" status */
ed486911	146	char print_buffer[8192], /* Print data buffer */
	147	print_ptr, / Pointer into print data buffer */
	148	bc_buffer[1024]; /* Back-channel data buffer */
568fa3fa MS	149	struct timeval timeout; /* Timeout for select() */
	150	time_t curtime, /* Current time */
	151	snmp_update = 0;
ed486911	152	#if defined(HAVE_SIGACTION) && !defined(HAVE_SIGSET)
	153	struct sigaction action; /* Actions for POSIX signals */
	154	#endif /* HAVE_SIGACTION && !HAVE_SIGSET */
	155
	156
c0e1af83	157	fprintf(stderr,
568fa3fa MS	158	"DEBUG: backendRunLoop(print_fd=%d, device_fd=%d, snmp_fd=%d, "
	159	"addr=%p, use_bc=%d, side_cb=%p)\n",
	160	print_fd, device_fd, snmp_fd, addr, use_bc, side_cb);
8ca02f3c	161
ed486911	162	/*
	163	* If we are printing data from a print driver on stdin, ignore SIGTERM
	164	* so that the driver can finish out any page data, e.g. to eject the
	165	* current page. We only do this for stdin printing as otherwise there
	166	* is no way to cancel a raw print job...
	167	*/
	168
	169	if (!print_fd)
	170	{
	171	#ifdef HAVE_SIGSET /* Use System V signals over POSIX to avoid bugs */
	172	sigset(SIGTERM, SIG_IGN);
	173	#elif defined(HAVE_SIGACTION)
	174	memset(&action, 0, sizeof(action));
	175
	176	sigemptyset(&action.sa_mask);
	177	action.sa_handler = SIG_IGN;
	178	sigaction(SIGTERM, &action, NULL);
	179	#else
	180	signal(SIGTERM, SIG_IGN);
	181	#endif /* HAVE_SIGSET */
	182	}
4e6f60f0 MS	183	else if (print_fd < 0)
	184	{
	185	/*
	186	* Copy print data from stdin, but don't mess with the signal handlers...
	187	*/
	188
	189	print_fd = 0;
	190	}
ed486911	191
	192	/*
	193	* Figure out the maximum file descriptor value to use with select()...
	194	*/
	195
	196	nfds = (print_fd > device_fd ? print_fd : device_fd) + 1;
	197
	198	/*
	199	* Now loop until we are out of data from print_fd...
	200	*/
	201
b94498cf	202	for (print_bytes = 0, print_ptr = print_buffer, offline = -1,
b94498cf	203	paperout = -1, total_bytes = 0;;)
ed486911	204	{
	205	/*
	206	* Use select() to determine whether we have data to copy around...
	207	*/
	208
	209	FD_ZERO(&input);
	210	if (!print_bytes)
	211	FD_SET(print_fd, &input);
	212	if (use_bc)
	213	FD_SET(device_fd, &input);
dd1abb6b	214	if (!print_bytes && side_cb)
f7deaa1a	215	FD_SET(CUPS_SC_FD, &input);
ed486911	216
ed486911	217	FD_ZERO(&output);
91c84a35	218	if (print_bytes \|\| (!use_bc && !side_cb))
ed486911	219	FD_SET(device_fd, &output);
ed486911	220
f7deaa1a	221	if (use_bc \|\| side_cb)
8ca02f3c	222	{
568fa3fa MS	223	timeout.tv_sec = 5;
	224	timeout.tv_usec = 0;
	225
	226	if (select(nfds, &input, &output, NULL, &timeout) < 0)
8ca02f3c	227	{
	228	/*
	229	* Pause printing to clear any pending errors...
	230	*/
	231
ef55b745	232	if (errno == ENXIO && offline != 1 && update_state)
8ca02f3c	233	{
c5571a1d	234	fputs("STATE: +offline-report\n", stderr);
0837b7e8	235	_cupsLangPrintFilter(stderr, "INFO",
f3c17241	236	_("The printer is not connected."));
8ca02f3c	237	offline = 1;
8ca02f3c	238	}
b94498cf	239	else if (errno == EINTR && total_bytes == 0)
	240	{
	241	fputs("DEBUG: Received an interrupt before any bytes were "
c8fef167	242	"written, aborting.\n", stderr);
b94498cf	243	return (0);
b94498cf	244	}
8ca02f3c	245
	246	sleep(1);
	247	continue;
	248	}
	249	}
ed486911	250
f7deaa1a	251	/*
	252	* Check if we have a side-channel request ready...
	253	*/
	254
	255	if (side_cb && FD_ISSET(CUPS_SC_FD, &input))
dd1abb6b MS	256	{
	257	/*
	258	* Do the side-channel request, then start back over in the select
	259	* loop since it may have read from print_fd...
	260	*/
	261
18ecb428 MS	262	if ((*side_cb)(print_fd, device_fd, snmp_fd, addr, use_bc))
18ecb428 MS	263	side_cb = NULL;
dd1abb6b MS	264	continue;
dd1abb6b MS	265	}
f7deaa1a	266
ed486911	267	/*
	268	* Check if we have back-channel data ready...
	269	*/
	270
	271	if (FD_ISSET(device_fd, &input))
	272	{
	273	if ((bc_bytes = read(device_fd, bc_buffer, sizeof(bc_buffer))) > 0)
	274	{
	275	fprintf(stderr,
4d301e69	276	"DEBUG: Received " CUPS_LLFMT " bytes of back-channel data\n",
ed486911	277	CUPS_LLCAST bc_bytes);
7e86f2f6	278	cupsBackChannelWrite(bc_buffer, (size_t)bc_bytes, 1.0);
ed486911	279	}
4b3f67ff MS	280	else if (bc_bytes < 0 && errno != EAGAIN && errno != EINTR)
	281	{
	282	fprintf(stderr, "DEBUG: Error reading back-channel data: %s\n",
	283	strerror(errno));
	284	use_bc = 0;
	285	}
7cf5915e MS	286	else if (bc_bytes == 0)
7cf5915e MS	287	use_bc = 0;
ed486911	288	}
	289
	290	/*
	291	* Check if we have print data ready...
	292	*/
	293
	294	if (FD_ISSET(print_fd, &input))
	295	{
	296	if ((print_bytes = read(print_fd, print_buffer,
	297	sizeof(print_buffer))) < 0)
	298	{
	299	/*
	300	* Read error - bail if we don't see EAGAIN or EINTR...
	301	*/
	302
0b1399a2	303	if (errno != EAGAIN && errno != EINTR)
ed486911	304	{
f3c17241 MS	305	fprintf(stderr, "DEBUG: Read failed: %s\n", strerror(errno));
	306	_cupsLangPrintFilter(stderr, "ERROR",
	307	_("Unable to read print data."));
ed486911	308	return (-1);
	309	}
	310
	311	print_bytes = 0;
	312	}
	313	else if (print_bytes == 0)
	314	{
	315	/*
	316	* End of file, break out of the loop...
	317	*/
	318
	319	break;
	320	}
	321
	322	print_ptr = print_buffer;
8ca02f3c	323
	324	fprintf(stderr, "DEBUG: Read %d bytes of print data...\n",
	325	(int)print_bytes);
ed486911	326	}
	327
	328	/*
	329	* Check if the device is ready to receive data and we have data to
	330	* send...
	331	*/
	332
	333	if (print_bytes && FD_ISSET(device_fd, &output))
	334	{
7e86f2f6	335	if ((bytes = write(device_fd, print_ptr, (size_t)print_bytes)) < 0)
ed486911	336	{
	337	/*
	338	* Write error - bail if we don't see an error we can retry...
	339	*/
	340
	341	if (errno == ENOSPC)
	342	{
ef55b745	343	if (paperout != 1 && update_state)
ed486911	344	{
c5571a1d	345	fputs("STATE: +media-empty-warning\n", stderr);
0837b7e8	346	fputs("DEBUG: Out of paper\n", stderr);
ed486911	347	paperout = 1;
	348	}
	349	}
8ca02f3c	350	else if (errno == ENXIO)
8ca02f3c	351	{
ef55b745	352	if (offline != 1 && update_state)
8ca02f3c	353	{
c5571a1d	354	fputs("STATE: +offline-report\n", stderr);
0837b7e8	355	_cupsLangPrintFilter(stderr, "INFO",
f3c17241	356	_("The printer is not connected."));
8ca02f3c	357	offline = 1;
	358	}
	359	}
ed486911	360	else if (errno != EAGAIN && errno != EINTR && errno != ENOTTY)
ed486911	361	{
0837b7e8	362	_cupsLangPrintError("ERROR", _("Unable to write print data"));
ed486911	363	return (-1);
	364	}
	365	}
	366	else
	367	{
ef55b745	368	if (paperout && update_state)
ed486911	369	{
c5571a1d	370	fputs("STATE: -media-empty-warning\n", stderr);
ed486911	371	paperout = 0;
	372	}
	373
ef55b745	374	if (offline && update_state)
8ca02f3c	375	{
c5571a1d	376	fputs("STATE: -offline-report\n", stderr);
f3c17241 MS	377	_cupsLangPrintFilter(stderr, "INFO",
f3c17241 MS	378	_("The printer is now connected."));
8ca02f3c	379	offline = 0;
	380	}
	381
	382	fprintf(stderr, "DEBUG: Wrote %d bytes of print data...\n", (int)bytes);
ed486911	383
	384	print_bytes -= bytes;
	385	print_ptr += bytes;
	386	total_bytes += bytes;
	387	}
	388	}
568fa3fa MS	389
	390	/*
	391	* Do SNMP updates periodically...
	392	*/
	393
	394	if (snmp_fd >= 0 && time(&curtime) >= snmp_update)
	395	{
	396	if (backendSNMPSupplies(snmp_fd, addr, NULL, NULL))
	397	snmp_update = INT_MAX;
	398	else
	399	snmp_update = curtime + 5;
	400	}
ed486911	401	}
	402
	403	/*
	404	* Return with success...
	405	*/
	406
	407	return (total_bytes);
	408	}
	409
	410
	411	/*
c8fef167 MS	412	* 'backendWaitLoop()' - Wait for input from stdin while handling side-channel
	413	* queries.
	414	*/
	415
	416	int /* O - 1 if data is ready, 0 if not */
	417	backendWaitLoop(
	418	int snmp_fd, /* I - SNMP socket or -1 if none */
	419	http_addr_t addr, / I - Address of device */
f14324a7	420	int use_bc, /* I - Use back-channel? */
c8fef167 MS	421	_cups_sccb_t side_cb) /* I - Side-channel callback */
c8fef167 MS	422	{
82cc1f9a MS	423	int nfds; /* Number of file descriptors */
	424	fd_set input; /* Input set for reading */
	425	time_t curtime = 0, /* Current time */
	426	snmp_update = 0;/* Last SNMP status update */
	427	struct timeval timeout; /* Timeout for select() */
c8fef167 MS	428
	429
	430	fprintf(stderr, "DEBUG: backendWaitLoop(snmp_fd=%d, addr=%p, side_cb=%p)\n",
	431	snmp_fd, addr, side_cb);
	432
	433	/*
	434	* Now loop until we receive data from stdin...
	435	*/
	436
82cc1f9a MS	437	if (snmp_fd >= 0)
	438	snmp_update = time(NULL) + 5;
	439
c8fef167 MS	440	for (;;)
	441	{
	442	/*
	443	* Use select() to determine whether we have data to copy around...
	444	*/
	445
	446	FD_ZERO(&input);
	447	FD_SET(0, &input);
	448	if (side_cb)
	449	FD_SET(CUPS_SC_FD, &input);
	450
82cc1f9a MS	451	if (snmp_fd >= 0)
	452	{
	453	curtime = time(NULL);
	454	timeout.tv_sec = curtime >= snmp_update ? 0 : snmp_update - curtime;
	455	timeout.tv_usec = 0;
	456
	457	nfds = select(CUPS_SC_FD + 1, &input, NULL, NULL, &timeout);
	458	}
	459	else
	460	nfds = select(CUPS_SC_FD + 1, &input, NULL, NULL, NULL);
	461
	462	if (nfds < 0)
c8fef167 MS	463	{
	464	/*
	465	* Pause printing to clear any pending errors...
	466	*/
	467
	468	if (errno == EINTR)
	469	{
	470	fputs("DEBUG: Received an interrupt before any bytes were "
	471	"written, aborting.\n", stderr);
	472	return (0);
	473	}
	474
	475	sleep(1);
	476	continue;
	477	}
	478
	479	/*
	480	* Check for input on stdin...
	481	*/
	482
	483	if (FD_ISSET(0, &input))
	484	break;
	485
	486	/*
	487	* Check if we have a side-channel request ready...
	488	*/
	489
	490	if (side_cb && FD_ISSET(CUPS_SC_FD, &input))
	491	{
	492	/*
	493	* Do the side-channel request, then start back over in the select
	494	* loop since it may have read from print_fd...
	495	*/
	496
f14324a7	497	if ((*side_cb)(0, -1, snmp_fd, addr, use_bc))
c8fef167 MS	498	side_cb = NULL;
	499	continue;
	500	}
	501
	502	/*
	503	* Do SNMP updates periodically...
	504	*/
	505
82cc1f9a	506	if (snmp_fd >= 0 && curtime >= snmp_update)
c8fef167 MS	507	{
c8fef167 MS	508	if (backendSNMPSupplies(snmp_fd, addr, NULL, NULL))
82cc1f9a	509	snmp_fd = -1;
c8fef167 MS	510	else
	511	snmp_update = curtime + 5;
	512	}
	513	}
	514
	515	/*
	516	* Return with success...
	517	*/
	518
	519	return (1);
	520	}