[LinuxPPS] PPS/ntpd fails on fresh startup

[Luca Bertagnolio]

On Wed, Oct 15, 2008 at 12:08 PM, Rodolfo Giometti
<giometti at enneenne.com> wrote:
> Luca, what exactly the refclock_open() does with such parameter? And
> how it is defined inside the code?

there you go:

/*
 * refclock_open - open serial port for reference clock
 *
 * This routine opens a serial port for I/O and sets default options. It
 * returns the file descriptor if success and zero if failure.
 */
int
refclock_open(
        char    *dev,           /* device name pointer */
        u_int   speed,          /* serial port speed (code) */
        u_int   lflags          /* line discipline flags */
        )
{
        int     fd;
        int     omode;

        /*
         * Open serial port and set default options
         */
        omode = O_RDWR;
#ifdef O_NONBLOCK
        omode |= O_NONBLOCK;
#endif
#ifdef O_NOCTTY
        omode |= O_NOCTTY;
#endif

        fd = open(dev, omode, 0777);
        if (fd < 0) {
                msyslog(LOG_ERR, "refclock_open %s: %m", dev);
                return (0);
        }
        if (!refclock_setup(fd, speed, lflags)) {
                close(fd);
                return (0);
        }
        if (!refclock_ioctl(fd, lflags)) {
                close(fd);
                return (0);
        }
        return (fd);
}

refclock_ioctl is defined as such:

/*
 * refclock_ioctl - set serial port control functions
 *
 * This routine attempts to hide the internal, system-specific details
 * of serial ports. It can handle POSIX (termios), SYSV (termio) and BSD
 * (sgtty) interfaces with varying degrees of success. The routine sets
 * up optional features such as tty_clk. The routine returns 1 if
 * success and 0 if failure.
 */
int
refclock_ioctl(
        int     fd,             /* file descriptor */
        u_int   lflags          /* line discipline flags */
        )
{
        /*
         * simply return 1 if no UNIX line discipline is supported
         */
#if !defined SYS_VXWORKS && !defined SYS_WINNT
#if defined(HAVE_TERMIOS) || defined(HAVE_SYSV_TTYS) || defined(HAVE_BSD_TTYS)

#ifdef DEBUG
        if (debug)
                printf("refclock_ioctl: fd %d flags 0x%x\n", fd,
                    lflags);
#endif
#ifdef TTYCLK

        /*
         * The TTYCLK option provides timestamping at the driver level.
         * It requires the tty_clk streams module and System V STREAMS
         * support. If not available, don't complain.
         */
        if (lflags & (LDISC_CLK | LDISC_CLKPPS | LDISC_ACTS)) {
                int rval = 0;

                if (ioctl(fd, I_PUSH, "clk") < 0) {
                        msyslog(LOG_NOTICE,
                            "refclock_ioctl fd %d I_PUSH: %m", fd);
                        return (0);
#ifdef CLK_SETSTR
                } else {
                        char *str;

                        if (lflags & LDISC_CLKPPS)
                                str = "\377";
                        else if (lflags & LDISC_ACTS)
                                str = "*";
                        else
                                str = "\n";
                        if (ioctl(fd, CLK_SETSTR, str) < 0) {
                                msyslog(LOG_ERR,
                                    "refclock_ioctl fd %d CLK_SETSTR: %m", fd);
                                return (0);
                        }
#endif /*CLK_SETSTR */
                }
        }
#endif /* TTYCLK */
#endif /* HAVE_TERMIOS || HAVE_SYSV_TTYS || HAVE_BSD_TTYS */
#endif /* SYS_VXWORKS SYS_WINNT */
        return (1);
}

and this is there is some reference to LDISC flags and their use in
the true ioctl.

HTH  --L