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

/*
 * "$Id: runloop.c 6170 2007-01-02 17:26:41Z 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 = 0, paperout = 0, 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)
	{
	  fputs("STATE: +offline-error\n", stderr);
	  fputs("INFO: Printer is currently off-line.\n", stderr);
	  offline = 1;
	}

	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)
	  {
	    fputs("ERROR: Out of paper!\n", stderr);
	    fputs("STATE: +media-empty-error\n", stderr);
	    paperout = 1;
	  }
        }
	else if (errno == ENXIO)
	{
	  if (!offline)
	  {
	    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)
	{
	  perror("ERROR: Unable to write print data");
	  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 6170 2007-01-02 17:26:41Z mike $".
 */
Commit	Line	Data
ed486911	1	/*
f7deaa1a	2	* "$Id: runloop.c 6170 2007-01-02 17:26:41Z 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
8ca02f3c	71	fprintf(stderr, "DEBUG: backendRunLoop(print_fd=%d, device_fd=%d, use_bc=%d)\n",
	72	print_fd, device_fd, use_bc);
	73
ed486911	74	/*
	75	* If we are printing data from a print driver on stdin, ignore SIGTERM
	76	* so that the driver can finish out any page data, e.g. to eject the
	77	* current page. We only do this for stdin printing as otherwise there
	78	* is no way to cancel a raw print job...
	79	*/
	80
	81	if (!print_fd)
	82	{
	83	#ifdef HAVE_SIGSET /* Use System V signals over POSIX to avoid bugs */
	84	sigset(SIGTERM, SIG_IGN);
	85	#elif defined(HAVE_SIGACTION)
	86	memset(&action, 0, sizeof(action));
	87
	88	sigemptyset(&action.sa_mask);
	89	action.sa_handler = SIG_IGN;
	90	sigaction(SIGTERM, &action, NULL);
	91	#else
	92	signal(SIGTERM, SIG_IGN);
	93	#endif /* HAVE_SIGSET */
	94	}
	95
	96	/*
	97	* Figure out the maximum file descriptor value to use with select()...
	98	*/
	99
	100	nfds = (print_fd > device_fd ? print_fd : device_fd) + 1;
	101
	102	/*
	103	* Now loop until we are out of data from print_fd...
	104	*/
	105
8ca02f3c	106	for (print_bytes = 0, print_ptr = print_buffer, offline = 0, paperout = 0, total_bytes = 0;;)
ed486911	107	{
	108	/*
	109	* Use select() to determine whether we have data to copy around...
	110	*/
	111
	112	FD_ZERO(&input);
	113	if (!print_bytes)
	114	FD_SET(print_fd, &input);
	115	if (use_bc)
	116	FD_SET(device_fd, &input);
f7deaa1a	117	if (side_cb)
f7deaa1a	118	FD_SET(CUPS_SC_FD, &input);
ed486911	119
ed486911	120	FD_ZERO(&output);
8ca02f3c	121	if (print_bytes \|\| !use_bc)
ed486911	122	FD_SET(device_fd, &output);
ed486911	123
f7deaa1a	124	if (use_bc \|\| side_cb)
8ca02f3c	125	{
	126	if (select(nfds, &input, &output, NULL, NULL) < 0)
	127	{
	128	/*
	129	* Pause printing to clear any pending errors...
	130	*/
	131
	132	if (errno == ENXIO && !offline)
	133	{
	134	fputs("STATE: +offline-error\n", stderr);
	135	fputs("INFO: Printer is currently off-line.\n", stderr);
	136	offline = 1;
	137	}
	138
	139	sleep(1);
	140	continue;
	141	}
	142	}
ed486911	143
f7deaa1a	144	/*
	145	* Check if we have a side-channel request ready...
	146	*/
	147
	148	if (side_cb && FD_ISSET(CUPS_SC_FD, &input))
	149	(*side_cb)(print_fd, device_fd, use_bc);
	150
ed486911	151	/*
	152	* Check if we have back-channel data ready...
	153	*/
	154
	155	if (FD_ISSET(device_fd, &input))
	156	{
	157	if ((bc_bytes = read(device_fd, bc_buffer, sizeof(bc_buffer))) > 0)
	158	{
	159	fprintf(stderr,
	160	"DEBUG: Received " CUPS_LLFMT " bytes of back-channel data!\n",
	161	CUPS_LLCAST bc_bytes);
	162	cupsBackChannelWrite(bc_buffer, bc_bytes, 1.0);
	163	}
	164	}
	165
	166	/*
	167	* Check if we have print data ready...
	168	*/
	169
	170	if (FD_ISSET(print_fd, &input))
	171	{
	172	if ((print_bytes = read(print_fd, print_buffer,
	173	sizeof(print_buffer))) < 0)
	174	{
	175	/*
	176	* Read error - bail if we don't see EAGAIN or EINTR...
	177	*/
	178
	179	if (errno != EAGAIN \|\| errno != EINTR)
	180	{
	181	perror("ERROR: Unable to read print data");
	182	return (-1);
	183	}
	184
	185	print_bytes = 0;
	186	}
	187	else if (print_bytes == 0)
	188	{
	189	/*
	190	* End of file, break out of the loop...
	191	*/
	192
	193	break;
	194	}
	195
	196	print_ptr = print_buffer;
8ca02f3c	197
	198	fprintf(stderr, "DEBUG: Read %d bytes of print data...\n",
	199	(int)print_bytes);
ed486911	200	}
	201
	202	/*
	203	* Check if the device is ready to receive data and we have data to
	204	* send...
	205	*/
	206
	207	if (print_bytes && FD_ISSET(device_fd, &output))
	208	{
	209	if ((bytes = write(device_fd, print_ptr, print_bytes)) < 0)
	210	{
	211	/*
	212	* Write error - bail if we don't see an error we can retry...
	213	*/
	214
	215	if (errno == ENOSPC)
	216	{
	217	if (!paperout)
	218	{
	219	fputs("ERROR: Out of paper!\n", stderr);
b86bc4cf	220	fputs("STATE: +media-empty-error\n", stderr);
ed486911	221	paperout = 1;
	222	}
	223	}
8ca02f3c	224	else if (errno == ENXIO)
	225	{
	226	if (!offline)
	227	{
	228	fputs("STATE: +offline-error\n", stderr);
	229	fputs("INFO: Printer is currently off-line.\n", stderr);
	230	offline = 1;
	231	}
	232	}
ed486911	233	else if (errno != EAGAIN && errno != EINTR && errno != ENOTTY)
	234	{
	235	perror("ERROR: Unable to write print data");
	236	return (-1);
	237	}
	238	}
	239	else
	240	{
	241	if (paperout)
	242	{
b86bc4cf	243	fputs("STATE: -media-empty-error\n", stderr);
ed486911	244	paperout = 0;
	245	}
	246
8ca02f3c	247	if (offline)
	248	{
	249	fputs("STATE: -offline-error\n", stderr);
	250	fputs("INFO: Printer is now on-line.\n", stderr);
	251	offline = 0;
	252	}
	253
	254	fprintf(stderr, "DEBUG: Wrote %d bytes of print data...\n", (int)bytes);
ed486911	255
	256	print_bytes -= bytes;
	257	print_ptr += bytes;
	258	total_bytes += bytes;
	259	}
	260	}
	261	}
	262
	263	/*
	264	* Return with success...
	265	*/
	266
	267	return (total_bytes);
	268	}
	269
	270
	271	/*
f7deaa1a	272	* End of "$Id: runloop.c 6170 2007-01-02 17:26:41Z mike $".
ed486911	273	*/