usenet@cps3xx.UUCP (Usenet file owner) (08/10/89)
Here is a C language program to replace the Korn shell printer "shuttle"
posted earlier (by Tw Cook of HP, I believe).
We decided to use a program instead of a shell script mainly so we could
prevent jobs from falling into a black hole when the printer is offline.
The following program has not been exhaustively tested. Use at your own risk.
-----------------------------------------------------------------------------
/* shuttle.c ************************************************************
* *
* Usage: shuttle <fifo> <printer-device> *
* *
* A kludge for HP-UX 6.5 to get around the problem of not being able *
* to hang spooled devices on a cnode. This program sits between a *
* named pipe, visible on both the server and cnode, and the printer *
* device. The server spools to the named pipe, and the shuttle on the *
* cnode takes stuff out of the pipe and throws it at the device. *
* *
* This is still a kludge, waiting on a better solution (a distributed *
* spooling system) from HP. We do not handle all possible errors, and *
* there is no way to inform the scheduler/user of printer errors. *
* *
* We assume that Carier Detect (CD - RS232C pin 8) is wired to be *
* active when the printer is accepting output. For an NEC SilentWriter *
* on an HP 9000/340 a cable like this works (see termio(7) and modem(7)*
* for the gory details): *
* *
* NEC 2 3 HP *
* 3 2 *
* 7 7 *
* 20 8 *
* *
* Be sure the device has modem controls enabled, for example under *
* HP-UX 6.5: "/etc/mknod lp09 c 1 0x090000" for the serial port. *
*----------------------------------------------------------------------*
* Modification history: *
* 89-08-09 original coding John Lees *
* *
* A. H. Case Center for Computer-Aided Engineering and Manufacturing *
* Michigan State University, East Lansing, Michigan 48824-1226 *
* manager@frith.egr.msu.edu, ...!uunet!frith!manager *
************************************************************************
*/
#include <stdio.h>
#include <string.h>
#include <fcntl.h>
#include <termio.h>
#include <sys/ioctl.h>
#include <sys/modem.h>
#include <sys/types.h>
#include <sys/stat.h>
#include "misc.h"
#define BUF_SIZE 8192
extern char *strerror();
extern int errno;
void usage();
main(argc, argv)
int argc;
char *argv[];
{
char dev_buf[132], fifo_buf[BUF_SIZE], *whoami;
int debug, dev_fd, fifo_fd, n_read, n_wrote, rs232;
struct termio our_termio, *termio_p = &our_termio;
mflag modem, *p_modem = &modem;
/*
*** Remember who we are.
*/
whoami = argv[0];
/*
*** Scan "-" arguments.
*/
argc--;
argv++;
while (argc && argv[0][0] == '-')
{
switch (argv[0][1])
{
case 'd': /* set debug flag */
debug = TRUE;
break;
default: /* ignore crud */
break;
}
argc--;
argv++;
} /* while */
if (debug)
fprintf(stderr, "%s: *** debug mode ***\n", whoami);
/*
*** Get the name of the FIFO and open it.
*/
if (argc != 0)
{
if ((fifo_fd = open(argv[0], O_RDONLY)) < 0)
{
fprintf(stderr, "%s: Cannot open FIFO \"%s\"\n\t%s\n",
whoami, argv[0], strerror(errno));
exit(1);
}
argc--;
argv++;
}
else
{
usage(whoami);
exit(1);
}
/*
*** Get the name of the printer device and set it up.
*/
if (argc != 0)
{
/* Open.
*/
if ((dev_fd = open(argv[0], O_RDWR)) < 0)
{
fprintf(stderr, "%s: Cannot open printer device \"%s\"\n\t%s\n",
whoami, argv[0], strerror(errno));
exit(1);
}
/* Set up the serial port. (If the ioctl fails, we assume this is
* not a serial port.)
*/
if (ioctl(dev_fd, TCGETA, termio_p) >= 0)
{
rs232 = TRUE;
termio_p->c_iflag = IXON | IXANY;
termio_p->c_oflag = 0;
termio_p->c_cflag = B9600 | CS8 | CREAD;
termio_p->c_lflag = 0;
if (ioctl(dev_fd, TCSETA, termio_p) < 0)
{
fprintf(stderr, "%s: ioctl TCSETA on printer device \"%s\"\n\t%s\n",
whoami, argv[0], strerror(errno));
exit(1);
}
else
if (debug)
{
fprintf(stderr, "c_iflag = %o\n", termio_p->c_iflag);
fprintf(stderr, "c_oflag = %o\n", termio_p->c_oflag);
fprintf(stderr, "c_cflag = %o\n", termio_p->c_cflag);
fprintf(stderr, "c_lflag = %o\n", termio_p->c_lflag);
}
}
else
{
rs232 = FALSE;
if (debug)
fprintf(stderr, "%s: ioctl TCGETA on printer device \"%s\"\n\t%s\n",
whoami, argv[0], strerror(errno));
}
argc--;
argv++;
}
else
{
usage(whoami);
close(fifo_fd);
exit(1);
}
/*
*** Check for invalid arguments.
*/
if (argc != 0)
{
fprintf(stderr, "%s: Invalid argument \"%s\"\n", whoami, argv[0]);
close(fifo_fd);
close(dev_fd);
exit(1);
}
/*
*** Here we loop forever checking if there is anything in the FIFO to
*** throw at the printer.
***
*** We check for a read of size zero and sleep. The read from the fifo
*** should block, but it doesn't (without this check, the read loop
*** placed a 45% load on our ethernet!).
*/
FOREVER
{
n_read = read(fifo_fd, fifo_buf, BUF_SIZE);
if (n_read < 0) /* FIFO error */
{
fprintf(stderr, "%s: FIFO error\n\t%s\n",
whoami, strerror(errno));
n_read = 0;
}
if (n_read == 0) /* FIFO empty */
{
sleep((unsigned long)5);
}
if (n_read > 0) /* FIFO read okay */
{
/* Don't print if the printer is not available.
*/
dcd_check:
if (rs232)
ioctl(dev_fd, MCGETA, p_modem);
if (!rs232 || (modem & MDCD))
{
n_wrote = write(dev_fd, fifo_buf, n_read);
if (n_wrote < 0)
{
fprintf(stderr, "%s: Printer device error\n\t%s\n",
whoami, strerror(errno));
n_wrote = 0;
}
}
else
{
if (debug)
fprintf(stderr, "*** no DCD %o ***\n", modem);
sleep((unsigned long)5);
goto dcd_check;
}
}
} /* forever */
} /* main */
void usage(whoami)
char *whoami;
{
fprintf(stderr, "Usage: %s <fifo> <printer-dev>\n", whoami);
}
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - O - - -
John Lees, Manager of A. H. Case Center for Computer OoO
Systems & Network Services Aided Engineering & Manufacturing /O
236 Engineering Building |
lees@frith.egr.msu.edu Michigan State University (|)
...!uunet!frith!lees East Lansing, MI 48824-1226 | flower
CompuServe 74106,1324 Phone: (517) 355-7435/6453 __|__ power