4  * Copyright © 2020-2024 by OpenPrinting.
5  * Copyright © 2007-2014 by Apple Inc.
6  * Copyright © 2006-2007 by Easy Software Products, all rights reserved.
16 #include "backend-private.h"
18 #include <sys/select.h>
22  * 'backendDrainOutput()' - Drain pending print data to the device.
25 int					/* O - 0 on success, -1 on error */
26 backendDrainOutput(int print_fd,	/* I - Print file descriptor */  in backendDrainOutput()
27                    int device_fd)	/* I - Device file descriptor */  in backendDrainOutput()
42   * Figure out the maximum file descriptor value to use with select()...  in backendDrainOutput()
54     * Use select() to determine whether we have data to copy around...  in backendDrainOutput()
63     if (select(nfds, &input, NULL, NULL, &timeout) < 0)  in backendDrainOutput()
64       return (-1);  in backendDrainOutput()
73       * Read error - bail if we don't see EAGAIN or EINTR...  in backendDrainOutput()
80 	return (-1);  in backendDrainOutput()
102         * Write error - bail if we don't see an error we can retry...  in backendDrainOutput()
109 	  return (-1);  in backendDrainOutput()
116         print_bytes -= bytes;  in backendDrainOutput()
125  * 'backendRunLoop()' - Read and write print and back-channel data.
128 ssize_t					/* O - Total bytes on success, -1 on error */
130     int          print_fd,		/* I - Print file descriptor */  in backendRunLoop()
131     int          device_fd,		/* I - Device file descriptor */  in backendRunLoop()
132     int          snmp_fd,		/* I - SNMP socket or -1 if none */  in backendRunLoop()
133     http_addr_t  *addr,			/* I - Address of device */  in backendRunLoop()
134     int          use_bc,		/* I - Use back-channel? */  in backendRunLoop()
135     int          update_state,		/* I - Update printer-state-reasons? */  in backendRunLoop()
136     _cups_sccb_t side_cb)		/* I - Side-channel callback */  in backendRunLoop()
146   int		offline;		/* "Off-line" status */  in backendRunLoop()
149 		bc_buffer[1024];	/* Back-channel data buffer */  in backendRunLoop()
150   struct timeval timeout;		/* Timeout for select() */  in backendRunLoop()
194   * Figure out the maximum file descriptor value to use with select()...  in backendRunLoop()
203   for (print_bytes = 0, print_ptr = print_buffer, offline = -1,  in backendRunLoop()
204            paperout = -1, total_bytes = 0;;)  in backendRunLoop()
207     * Use select() to determine whether we have data to copy around...  in backendRunLoop()
227       if (select(nfds, &input, &output, NULL, &timeout) < 0)  in backendRunLoop()
235 	  fputs("STATE: +offline-report\n", stderr);  in backendRunLoop()
253     * Check if we have a side-channel request ready...  in backendRunLoop()
259       * Do the side-channel request, then start back over in the select  in backendRunLoop()
269     * Check if we have back-channel data ready...  in backendRunLoop()
277 	        "DEBUG: Received " CUPS_LLFMT " bytes of back-channel data\n",  in backendRunLoop()
283         fprintf(stderr, "DEBUG: Error reading back-channel data: %s\n",  in backendRunLoop()
301         * Read error - bail if we don't see EAGAIN or EINTR...  in backendRunLoop()
309 	  return (-1);  in backendRunLoop()
330     * Check if the device is ready to receive data and we have data to  in backendRunLoop()
339         * Write error - bail if we don't see an error we can retry...  in backendRunLoop()
346 	    fputs("STATE: +media-empty-warning\n", stderr);  in backendRunLoop()
355 	    fputs("STATE: +offline-report\n", stderr);  in backendRunLoop()
364 	  return (-1);  in backendRunLoop()
371 	  fputs("STATE: -media-empty-warning\n", stderr);  in backendRunLoop()
377 	  fputs("STATE: -offline-report\n", stderr);  in backendRunLoop()
385         print_bytes -= bytes;  in backendRunLoop()
413  * 'backendWaitLoop()' - Wait for input from stdin while handling side-channel
417 int					/* O - 1 if data is ready, 0 if not */
419     int          snmp_fd,		/* I - SNMP socket or -1 if none */  in backendWaitLoop()
420     http_addr_t  *addr,			/* I - Address of device */  in backendWaitLoop()
421     int          use_bc,		/* I - Use back-channel? */  in backendWaitLoop()
422     _cups_sccb_t side_cb)		/* I - Side-channel callback */  in backendWaitLoop()
428   struct timeval	timeout;	/* Timeout for select() */  in backendWaitLoop()
444     * Use select() to determine whether we have data to copy around...  in backendWaitLoop()
455       timeout.tv_sec  = curtime >= snmp_update ? 0 : snmp_update - curtime;  in backendWaitLoop()
458       nfds = select(CUPS_SC_FD + 1, &input, NULL, NULL, &timeout);  in backendWaitLoop()
461       nfds = select(CUPS_SC_FD + 1, &input, NULL, NULL, NULL);  in backendWaitLoop()
488     * Check if we have a side-channel request ready...  in backendWaitLoop()
494       * Do the side-channel request, then start back over in the select  in backendWaitLoop()
498       if ((*side_cb)(0, -1, snmp_fd, addr, use_bc))  in backendWaitLoop()
510         snmp_fd = -1;  in backendWaitLoop()