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

/*
 * "$Id: runloop.c 6498 2007-04-30 21:40:33Z mike $"
 *
 *   Common run loop API for the Common UNIX Printing System (CUPS).
 *
 *   Copyright 2006-2007 by Easy Software Products, all rights reserved.
 *
 *   These coded instructions, statements, and computer programs are the
 *   property of Easy Software Products and are protected by Federal
 *   copyright law.  Distribution and use rights are outlined in the file
 *   "LICENSE" which should have been included with this file.  If this
 *   file is missing or damaged please contact Easy Software Products
 *   at:
 *
 *       Attn: CUPS Licensing Information
 *       Easy Software Products
 *       44141 Airport View Drive, Suite 204
 *       Hollywood, Maryland 20636 USA
 *
 *       Voice: (301) 373-9600
 *       EMail: cups-info@cups.org
 *         WWW: http://www.cups.org
 *
 *   This file is subject to the Apple OS-Developed Software exception.
 *
 * Contents:
 *
 *   backendRunLoop() - Read and write print and back-channel data.
 */

/*
 * Include necessary headers.
 */

#include "backend-private.h"
#ifdef __hpux
#  include <sys/time.h>
#else
#  include <sys/select.h>
#endif /* __hpux */


/*
 * '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  use_bc,			/* I - Use back-channel? */
    void (*side_cb)(int, int, int))	/* 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 */
#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, use_bc=%d)\n",
          print_fd, device_fd, use_bc);

 /*
  * 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 */
  }

 /*
  * 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 (side_cb)
      FD_SET(CUPS_SC_FD, &input);

    FD_ZERO(&output);
    if (print_bytes || !use_bc)
      FD_SET(device_fd, &output);

    if (use_bc || side_cb)
    {
      if (select(nfds, &input, &output, NULL, NULL) < 0)
      {
       /*
	* Pause printing to clear any pending errors...
	*/

	if (errno == ENXIO && offline != 1)
	{
	  fputs("STATE: +offline-error\n", stderr);
	  fputs(_("INFO: Printer is currently off-line.\n"), stderr);
	  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))
      (*side_cb)(print_fd, device_fd, use_bc);

   /*
    * 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, bc_bytes, 1.0);
      }
    }

   /*
    * 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)
	{
	  perror("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, print_bytes)) < 0)
      {
       /*
        * Write error - bail if we don't see an error we can retry...
	*/

        if (errno == ENOSPC)
	{
	  if (paperout != 1)
	  {
	    fputs("STATE: +media-empty-error\n", stderr);
	    fputs(_("ERROR: Out of paper!\n"), stderr);
	    paperout = 1;
	  }
        }
	else if (errno == ENXIO)
	{
	  if (offline != 1)
	  {
	    fputs("STATE: +offline-error\n", stderr);
	    fputs(_("INFO: Printer is currently off-line.\n"), stderr);
	    offline = 1;
	  }
	}
	else if (errno != EAGAIN && errno != EINTR && errno != ENOTTY)
	{
	  fprintf(stderr, _("ERROR: Unable to write print data: %s\n"),
	          strerror(errno));
	  return (-1);
	}
      }
      else
      {
        if (paperout)
	{
	  fputs("STATE: -media-empty-error\n", stderr);
	  paperout = 0;
	}

	if (offline)
	{
	  fputs("STATE: -offline-error\n", stderr);
	  fputs(_("INFO: Printer is now on-line.\n"), stderr);
	  offline = 0;
	}

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

        print_bytes -= bytes;
	print_ptr   += bytes;
	total_bytes += bytes;
      }
    }
  }

 /*
  * Return with success...
  */

  return (total_bytes);
}


/*
 * End of "$Id: runloop.c 6498 2007-04-30 21:40:33Z mike $".
 */
Commit	Line	Data
ed486911	1	/*
b94498cf	2	* "$Id: runloop.c 6498 2007-04-30 21:40:33Z mike $"
ed486911	3	*
	4	* Common run loop API for the Common UNIX Printing System (CUPS).
	5	*
f7deaa1a	6	* Copyright 2006-2007 by Easy Software Products, all rights reserved.
ed486911	7	*
	8	* These coded instructions, statements, and computer programs are the
	9	* property of Easy Software Products and are protected by Federal
	10	* copyright law. Distribution and use rights are outlined in the file
	11	* "LICENSE" which should have been included with this file. If this
	12	* file is missing or damaged please contact Easy Software Products
	13	* at:
	14	*
	15	* Attn: CUPS Licensing Information
	16	* Easy Software Products
	17	* 44141 Airport View Drive, Suite 204
	18	* Hollywood, Maryland 20636 USA
	19	*
	20	* Voice: (301) 373-9600
	21	* EMail: cups-info@cups.org
	22	* WWW: http://www.cups.org
	23	*
	24	* This file is subject to the Apple OS-Developed Software exception.
	25	*
	26	* Contents:
	27	*
	28	* backendRunLoop() - Read and write print and back-channel data.
	29	*/
	30
	31	/*
	32	* Include necessary headers.
	33	*/
	34
	35	#include "backend-private.h"
d09495fa	36	#ifdef __hpux
	37	# include <sys/time.h>
	38	#else
	39	# include <sys/select.h>
	40	#endif /* __hpux */
ed486911	41
	42
	43	/*
	44	* 'backendRunLoop()' - Read and write print and back-channel data.
	45	*/
	46
	47	ssize_t /* O - Total bytes on success, -1 on error */
f7deaa1a	48	backendRunLoop(
	49	int print_fd, /* I - Print file descriptor */
	50	int device_fd, /* I - Device file descriptor */
	51	int use_bc, /* I - Use back-channel? */
	52	void (side_cb)(int, int, int)) / I - Side-channel callback */
ed486911	53	{
	54	int nfds; /* Maximum file descriptor value + 1 */
	55	fd_set input, /* Input set for reading */
	56	output; /* Output set for writing */
	57	ssize_t print_bytes, /* Print bytes read */
	58	bc_bytes, /* Backchannel bytes read */
	59	total_bytes, /* Total bytes written */
	60	bytes; /* Bytes written */
	61	int paperout; /* "Paper out" status */
8ca02f3c	62	int offline; /* "Off-line" status */
ed486911	63	char print_buffer[8192], /* Print data buffer */
	64	print_ptr, / Pointer into print data buffer */
	65	bc_buffer[1024]; /* Back-channel data buffer */
	66	#if defined(HAVE_SIGACTION) && !defined(HAVE_SIGSET)
	67	struct sigaction action; /* Actions for POSIX signals */
	68	#endif /* HAVE_SIGACTION && !HAVE_SIGSET */
	69
	70
c0e1af83	71	fprintf(stderr,
c0e1af83	72	"DEBUG: backendRunLoop(print_fd=%d, device_fd=%d, use_bc=%d)\n",
8ca02f3c	73	print_fd, device_fd, use_bc);
8ca02f3c	74
ed486911	75	/*
	76	* If we are printing data from a print driver on stdin, ignore SIGTERM
	77	* so that the driver can finish out any page data, e.g. to eject the
	78	* current page. We only do this for stdin printing as otherwise there
	79	* is no way to cancel a raw print job...
	80	*/
	81
	82	if (!print_fd)
	83	{
	84	#ifdef HAVE_SIGSET /* Use System V signals over POSIX to avoid bugs */
	85	sigset(SIGTERM, SIG_IGN);
	86	#elif defined(HAVE_SIGACTION)
	87	memset(&action, 0, sizeof(action));
	88
	89	sigemptyset(&action.sa_mask);
	90	action.sa_handler = SIG_IGN;
	91	sigaction(SIGTERM, &action, NULL);
	92	#else
	93	signal(SIGTERM, SIG_IGN);
	94	#endif /* HAVE_SIGSET */
	95	}
	96
	97	/*
	98	* Figure out the maximum file descriptor value to use with select()...
	99	*/
	100
	101	nfds = (print_fd > device_fd ? print_fd : device_fd) + 1;
	102
	103	/*
	104	* Now loop until we are out of data from print_fd...
	105	*/
	106
b94498cf	107	for (print_bytes = 0, print_ptr = print_buffer, offline = -1,
b94498cf	108	paperout = -1, total_bytes = 0;;)
ed486911	109	{
	110	/*
	111	* Use select() to determine whether we have data to copy around...
	112	*/
	113
	114	FD_ZERO(&input);
	115	if (!print_bytes)
	116	FD_SET(print_fd, &input);
	117	if (use_bc)
	118	FD_SET(device_fd, &input);
f7deaa1a	119	if (side_cb)
f7deaa1a	120	FD_SET(CUPS_SC_FD, &input);
ed486911	121
ed486911	122	FD_ZERO(&output);
8ca02f3c	123	if (print_bytes \|\| !use_bc)
ed486911	124	FD_SET(device_fd, &output);
ed486911	125
f7deaa1a	126	if (use_bc \|\| side_cb)
8ca02f3c	127	{
	128	if (select(nfds, &input, &output, NULL, NULL) < 0)
	129	{
	130	/*
	131	* Pause printing to clear any pending errors...
	132	*/
	133
b94498cf	134	if (errno == ENXIO && offline != 1)
8ca02f3c	135	{
8ca02f3c	136	fputs("STATE: +offline-error\n", stderr);
c0e1af83	137	fputs(_("INFO: Printer is currently off-line.\n"), stderr);
8ca02f3c	138	offline = 1;
8ca02f3c	139	}
b94498cf	140	else if (errno == EINTR && total_bytes == 0)
	141	{
	142	fputs("DEBUG: Received an interrupt before any bytes were "
	143	"written, aborting!\n", stderr);
	144	return (0);
	145	}
8ca02f3c	146
	147	sleep(1);
	148	continue;
	149	}
	150	}
ed486911	151
f7deaa1a	152	/*
	153	* Check if we have a side-channel request ready...
	154	*/
	155
	156	if (side_cb && FD_ISSET(CUPS_SC_FD, &input))
	157	(*side_cb)(print_fd, device_fd, use_bc);
	158
ed486911	159	/*
	160	* Check if we have back-channel data ready...
	161	*/
	162
	163	if (FD_ISSET(device_fd, &input))
	164	{
	165	if ((bc_bytes = read(device_fd, bc_buffer, sizeof(bc_buffer))) > 0)
	166	{
	167	fprintf(stderr,
	168	"DEBUG: Received " CUPS_LLFMT " bytes of back-channel data!\n",
	169	CUPS_LLCAST bc_bytes);
	170	cupsBackChannelWrite(bc_buffer, bc_bytes, 1.0);
	171	}
	172	}
	173
	174	/*
	175	* Check if we have print data ready...
	176	*/
	177
	178	if (FD_ISSET(print_fd, &input))
	179	{
	180	if ((print_bytes = read(print_fd, print_buffer,
	181	sizeof(print_buffer))) < 0)
	182	{
	183	/*
	184	* Read error - bail if we don't see EAGAIN or EINTR...
	185	*/
	186
	187	if (errno != EAGAIN \|\| errno != EINTR)
	188	{
	189	perror("ERROR: Unable to read print data");
	190	return (-1);
	191	}
	192
	193	print_bytes = 0;
	194	}
	195	else if (print_bytes == 0)
	196	{
	197	/*
	198	* End of file, break out of the loop...
	199	*/
	200
	201	break;
	202	}
	203
	204	print_ptr = print_buffer;
8ca02f3c	205
	206	fprintf(stderr, "DEBUG: Read %d bytes of print data...\n",
	207	(int)print_bytes);
ed486911	208	}
	209
	210	/*
	211	* Check if the device is ready to receive data and we have data to
	212	* send...
	213	*/
	214
	215	if (print_bytes && FD_ISSET(device_fd, &output))
	216	{
	217	if ((bytes = write(device_fd, print_ptr, print_bytes)) < 0)
	218	{
	219	/*
	220	* Write error - bail if we don't see an error we can retry...
	221	*/
	222
	223	if (errno == ENOSPC)
	224	{
b94498cf	225	if (paperout != 1)
ed486911	226	{
b86bc4cf	227	fputs("STATE: +media-empty-error\n", stderr);
c0e1af83	228	fputs(_("ERROR: Out of paper!\n"), stderr);
ed486911	229	paperout = 1;
	230	}
	231	}
8ca02f3c	232	else if (errno == ENXIO)
8ca02f3c	233	{
b94498cf	234	if (offline != 1)
8ca02f3c	235	{
8ca02f3c	236	fputs("STATE: +offline-error\n", stderr);
c0e1af83	237	fputs(_("INFO: Printer is currently off-line.\n"), stderr);
8ca02f3c	238	offline = 1;
	239	}
	240	}
ed486911	241	else if (errno != EAGAIN && errno != EINTR && errno != ENOTTY)
ed486911	242	{
c0e1af83	243	fprintf(stderr, _("ERROR: Unable to write print data: %s\n"),
c0e1af83	244	strerror(errno));
ed486911	245	return (-1);
	246	}
	247	}
	248	else
	249	{
	250	if (paperout)
	251	{
b86bc4cf	252	fputs("STATE: -media-empty-error\n", stderr);
ed486911	253	paperout = 0;
	254	}
	255
8ca02f3c	256	if (offline)
	257	{
	258	fputs("STATE: -offline-error\n", stderr);
c0e1af83	259	fputs(_("INFO: Printer is now on-line.\n"), stderr);
8ca02f3c	260	offline = 0;
	261	}
	262
	263	fprintf(stderr, "DEBUG: Wrote %d bytes of print data...\n", (int)bytes);
ed486911	264
	265	print_bytes -= bytes;
	266	print_ptr += bytes;
	267	total_bytes += bytes;
	268	}
	269	}
	270	}
	271
	272	/*
	273	* Return with success...
	274	*/
	275
	276	return (total_bytes);
	277	}
	278
	279
	280	/*
b94498cf	281	* End of "$Id: runloop.c 6498 2007-04-30 21:40:33Z mike $".
ed486911	282	*/