sys-utils/hwclock-kd.c

/*
 * kd.c - KDGHWCLK stuff, possibly m68k only, likely to be deprecated
 */
#include "hwclock.h"

#ifdef __m68k__

# include <fcntl.h>
# include <sysexits.h>
# include <sys/ioctl.h>
# include <unistd.h>

# include "nls.h"

/* Get defines for KDGHWCLK and KDSHWCLK (m68k) */
# include <linux/kd.h>

/* Even on m68k, if KDGHWCLK (antique) is not defined, don't build this */

#endif

#if !defined(__m68k__) || !defined(KDGHWCLK)

#include <stddef.h>
struct clock_ops *probe_for_kd_clock(void)
{
	return NULL;
}

#else				/* __m68k__ && KDGHWCLK */

/* Opened by probe_for_kd_clock(), and never closed. */
static int con_fd = -1;
static char *con_fd_filename;	/* usually "/dev/tty1" */

/*
 * Wait for the top of a clock tick by calling KDGHWCLK in a busy loop until
 * we see it.
 */
static int synchronize_to_clock_tick_kd(void)
{
	/* The time when we were called (and started waiting) */
	struct hwclk_time start_time, nowtime;
	struct timeval begin, now;

	if (debug)
		printf(_("Waiting in loop for time from KDGHWCLK to change\n"));

	if (ioctl(con_fd, KDGHWCLK, &start_time) == -1) {
		warn(_("KDGHWCLK ioctl to read time failed"));
		return 3;
	}

	/*
	 * Wait for change. Should be within a second, but in case something
	 * weird happens, we have a time limit (1.5s) on this loop to reduce
	 * the impact of this failure.
	 */
	gettimeofday(&begin, NULL);
	do {
		/*
		 * Added by Roman Hodek <Roman.Hodek@informatik.uni-erlangen.de>
		 *
		 * "The culprit is the fast loop with KDGHWCLK ioctls. It
		 *  seems the kernel gets confused by those on Amigas with
		 *  A2000 RTCs and simply hangs after some time. Inserting a
		 *  sleep helps."
		 */
		xusleep(1);

		if (ioctl(con_fd, KDGHWCLK, &nowtime) == -1) {
			warn(_("KDGHWCLK ioctl to read time failed in loop"));
			return 3;
		}
		if (start_time.tm_sec != nowtime.tm_sec)
			break;
		gettimeofday(&now, NULL);
		if (time_diff(now, begin) > 1.5) {
			warnx(_("Timed out waiting for time change."));
			return 2;
		}
	} while (1);

	return 0;
}

/*
 * Read the hardware clock and return the current time via <tm> argument.
 * Use ioctls to /dev/tty1 on what we assume is an m68k machine.
 *
 * Note that we don't use /dev/console here. That might be a serial console.
 */
static int read_hardware_clock_kd(struct tm *tm)
{
	struct hwclk_time t;

	if (ioctl(con_fd, KDGHWCLK, &t) == -1) {
		warn(_("ioctl() failed to read time from %s"),
			  con_fd_filename);
		hwclock_exit(EX_IOERR);
	}

	tm->tm_sec = t.sec;
	tm->tm_min = t.min;
	tm->tm_hour = t.hour;
	tm->tm_mday = t.day;
	tm->tm_mon = t.mon;
	tm->tm_year = t.year;
	tm->tm_wday = t.wday;
	tm->tm_isdst = -1;	/* Don't know if it's Daylight Savings Time */

	return 0;
}

/*
 * Set the Hardware Clock to the time <new_broken_time>. Use ioctls to
 * /dev/tty1 on what we assume is an m68k machine.
 *
 * Note that we don't use /dev/console here. That might be a serial console.
 */
static int set_hardware_clock_kd(const struct tm *new_broken_time)
{
	struct hwclk_time t;

	t.sec = new_broken_time->tm_sec;
	t.min = new_broken_time->tm_min;
	t.hour = new_broken_time->tm_hour;
	t.day = new_broken_time->tm_mday;
	t.mon = new_broken_time->tm_mon;
	t.year = new_broken_time->tm_year;
	t.wday = new_broken_time->tm_wday;

	if (ioctl(con_fd, KDSHWCLK, &t) == -1) {
		warn(_("ioctl KDSHWCLK failed"));
		hwclock_exit(EX_IOERR);
	}
	return 0;
}

static int get_permissions_kd(void)
{
	return 0;
}

static struct clock_ops kd = {
	N_("Using the KDGHWCLK interface to m68k clock."),
	get_permissions_kd,
	read_hardware_clock_kd,
	set_hardware_clock_kd,
	synchronize_to_clock_tick_kd,
};

/* return &kd if KDGHWCLK works, NULL otherwise */
struct clock_ops *probe_for_kd_clock()
{
	struct clock_ops *ret = NULL;
	struct hwclk_time t;

	if (con_fd < 0) {	/* first time here */
		con_fd_filename = "/dev/tty1";
		con_fd = open(con_fd_filename, O_RDONLY);
	}
	if (con_fd < 0) {
		/* perhaps they are using devfs? */
		con_fd_filename = "/dev/vc/1";
		con_fd = open(con_fd_filename, O_RDONLY);
	}
	if (con_fd < 0) {
		/* probably KDGHWCLK exists on m68k only */
		warn(_("Can't open /dev/tty1 or /dev/vc/1"));
	} else {
		if (ioctl(con_fd, KDGHWCLK, &t) == -1) {
			if (errno != EINVAL)
				warn(_("KDGHWCLK ioctl failed"));
		} else
			ret = &kd;
	}
	return ret;
}
#endif				/* __m68k__ && KDGHWCLK */