1 files changed, 448 insertions, 0 deletions

diff --git a/sys-utils/hwclock-rtc.c b/sys-utils/hwclock-rtc.c
new file mode 100644
index 0000000..32feb35
--- /dev/null
+++ b/sys-utils/hwclock-rtc.c
@@ -0,0 +1,448 @@
+/*
+ * rtc.c - Use /dev/rtc for clock access
+ */
+#include <asm/ioctl.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/ioctl.h>
+#include <sys/select.h>
+#include <sys/time.h>
+#include <time.h>
+#include <unistd.h>
+
+#include "nls.h"
+
+#include "hwclock.h"
+
+/*
+ * Get defines for rtc stuff.
+ *
+ * Getting the rtc defines is nontrivial. The obvious way is by including
+ * <linux/mc146818rtc.h> but that again includes <asm/io.h> which again
+ * includes ... and on sparc and alpha this gives compilation errors for
+ * many kernel versions. So, we give the defines ourselves here. Moreover,
+ * some Sparc person decided to be incompatible, and used a struct rtc_time
+ * different from that used in mc146818rtc.h.
+ */
+
+/*
+ * On Sparcs, there is a <asm/rtc.h> that defines different ioctls (that are
+ * required on my machine). However, this include file does not exist on
+ * other architectures.
+ */
+/* One might do:
+#ifdef __sparc__
+# include <asm/rtc.h>
+#endif
+ */
+#ifdef __sparc__
+/* The following is roughly equivalent */
+struct sparc_rtc_time
+{
+	int sec;	/* Seconds		0-59 */
+	int min;	/* Minutes		0-59 */
+	int hour;	/* Hour			0-23 */
+	int dow;	/* Day of the week	1-7  */
+	int dom;	/* Day of the month	1-31 */
+	int month;	/* Month of year	1-12 */
+	int year;	/* Year			0-99 */
+};
+#define RTCGET _IOR('p', 20, struct sparc_rtc_time)
+#define RTCSET _IOW('p', 21, struct sparc_rtc_time)
+#endif
+
+/*
+ * struct rtc_time is present since 1.3.99.
+ * Earlier (since 1.3.89), a struct tm was used.
+ */
+struct linux_rtc_time {
+	int tm_sec;
+	int tm_min;
+	int tm_hour;
+	int tm_mday;
+	int tm_mon;
+	int tm_year;
+	int tm_wday;
+	int tm_yday;
+	int tm_isdst;
+};
+
+/* RTC_RD_TIME etc have this definition since 1.99.9 (pre2.0-9) */
+#ifndef RTC_RD_TIME
+# define RTC_RD_TIME	_IOR('p', 0x09, struct linux_rtc_time)
+# define RTC_SET_TIME	_IOW('p', 0x0a, struct linux_rtc_time)
+# define RTC_UIE_ON	_IO('p', 0x03)	/* Update int. enable on */
+# define RTC_UIE_OFF	_IO('p', 0x04)	/* Update int. enable off */
+#endif
+
+/* RTC_EPOCH_READ and RTC_EPOCH_SET are present since 2.0.34 and 2.1.89 */
+#ifndef RTC_EPOCH_READ
+# define RTC_EPOCH_READ	_IOR('p', 0x0d, unsigned long)	/* Read epoch */
+# define RTC_EPOCH_SET	_IOW('p', 0x0e, unsigned long)	/* Set epoch */
+#endif
+
+/*
+ * /dev/rtc is conventionally chardev 10/135
+ * ia64 uses /dev/efirtc, chardev 10/136
+ * devfs (obsolete) used /dev/misc/... for miscdev
+ * new RTC framework + udev uses dynamic major and /dev/rtc0.../dev/rtcN
+ * ... so we need an overridable default
+ */
+
+/* default or user defined dev (by hwclock --rtc=<path>) */
+static const char *rtc_dev_name;
+static int rtc_dev_fd = -1;
+
+static void close_rtc(void)
+{
+	if (rtc_dev_fd != -1)
+		close(rtc_dev_fd);
+	rtc_dev_fd = -1;
+}
+
+static int open_rtc(const struct hwclock_control *ctl)
+{
+	static const char *fls[] = {
+#ifdef __ia64__
+		"/dev/efirtc",
+		"/dev/misc/efirtc",
+#endif
+		"/dev/rtc0",
+		"/dev/rtc",
+		"/dev/misc/rtc"
+	};
+	size_t i;
+
+	if (rtc_dev_fd != -1)
+		return rtc_dev_fd;
+
+	/* --rtc option has been given */
+	if (ctl->rtc_dev_name) {
+		rtc_dev_name = ctl->rtc_dev_name;
+		rtc_dev_fd = open(rtc_dev_name, O_RDONLY);
+	} else {
+		for (i = 0; i < ARRAY_SIZE(fls); i++) {
+			if (ctl->verbose)
+				printf(_("Trying to open: %s\n"), fls[i]);
+			rtc_dev_fd = open(fls[i], O_RDONLY);
+
+			if (rtc_dev_fd < 0
+			    && (errno == ENOENT || errno == ENODEV))
+				continue;
+			rtc_dev_name = fls[i];
+			break;
+		}
+		if (rtc_dev_fd < 0)
+			rtc_dev_name = *fls;	/* default for error messages */
+	}
+	if (rtc_dev_fd != -1)
+		atexit(close_rtc);
+	return rtc_dev_fd;
+}
+
+static int open_rtc_or_exit(const struct hwclock_control *ctl)
+{
+	int rtc_fd = open_rtc(ctl);
+
+	if (rtc_fd < 0) {
+		warn(_("cannot open rtc device"));
+		hwclock_exit(ctl, EXIT_FAILURE);
+	}
+	return rtc_fd;
+}
+
+static int do_rtc_read_ioctl(int rtc_fd, struct tm *tm)
+{
+	int rc = -1;
+	char *ioctlname;
+#ifdef __sparc__
+	/* some but not all sparcs use a different ioctl and struct */
+	struct sparc_rtc_time stm;
+#endif
+
+	ioctlname = "RTC_RD_TIME";
+	rc = ioctl(rtc_fd, RTC_RD_TIME, tm);
+
+#ifdef __sparc__
+	if (rc == -1) {		/* sparc sbus */
+		ioctlname = "RTCGET";
+		rc = ioctl(rtc_fd, RTCGET, &stm);
+		if (rc == 0) {
+			tm->tm_sec = stm.sec;
+			tm->tm_min = stm.min;
+			tm->tm_hour = stm.hour;
+			tm->tm_mday = stm.dom;
+			tm->tm_mon = stm.month - 1;
+			tm->tm_year = stm.year - 1900;
+			tm->tm_wday = stm.dow - 1;
+			tm->tm_yday = -1;	/* day in the year */
+		}
+	}
+#endif
+
+	if (rc == -1) {
+		warn(_("ioctl(%s) to %s to read the time failed"),
+			ioctlname, rtc_dev_name);
+		return -1;
+	}
+
+	tm->tm_isdst = -1;	/* don't know whether it's dst */
+	return 0;
+}
+
+/*
+ * Wait for the top of a clock tick by reading /dev/rtc in a busy loop
+ * until we see it. This function is used for rtc drivers without ioctl
+ * interrupts. This is typical on an Alpha, where the Hardware Clock
+ * interrupts are used by the kernel for the system clock, so aren't at
+ * the user's disposal.
+ */
+static int busywait_for_rtc_clock_tick(const struct hwclock_control *ctl,
+				       const int rtc_fd)
+{
+	struct tm start_time;
+	/* The time when we were called (and started waiting) */
+	struct tm nowtime;
+	int rc;
+	struct timeval begin, now;
+
+	if (ctl->verbose) {
+		printf("ioctl(%d, RTC_UIE_ON, 0): %s\n",
+		       rtc_fd, strerror(errno));
+		printf(_("Waiting in loop for time from %s to change\n"),
+		       rtc_dev_name);
+	}
+
+	if (do_rtc_read_ioctl(rtc_fd, &start_time))
+		return 1;
+
+	/*
+	 * 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 {
+		rc = do_rtc_read_ioctl(rtc_fd, &nowtime);
+		if (rc || 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 1;
+		}
+	} while (1);
+
+	if (rc)
+		return 1;
+	return 0;
+}
+
+/*
+ * Same as synchronize_to_clock_tick(), but just for /dev/rtc.
+ */
+static int synchronize_to_clock_tick_rtc(const struct hwclock_control *ctl)
+{
+	int rtc_fd;		/* File descriptor of /dev/rtc */
+	int ret = 1;
+
+	rtc_fd = open_rtc(ctl);
+	if (rtc_fd == -1) {
+		warn(_("cannot open rtc device"));
+		return ret;
+	} else {
+		/* Turn on update interrupts (one per second) */
+		int rc = ioctl(rtc_fd, RTC_UIE_ON, 0);
+
+		if (rc != -1) {
+			/*
+			 * Just reading rtc_fd fails on broken hardware: no
+			 * update interrupt comes and a bootscript with a
+			 * hwclock call hangs
+			 */
+			fd_set rfds;
+			struct timeval tv;
+
+			/*
+			 * Wait up to ten seconds for the next update
+			 * interrupt
+			 */
+			FD_ZERO(&rfds);
+			FD_SET(rtc_fd, &rfds);
+			tv.tv_sec = 10;
+			tv.tv_usec = 0;
+			rc = select(rtc_fd + 1, &rfds, NULL, NULL, &tv);
+			if (0 < rc)
+				ret = 0;
+			else if (rc == 0) {
+				warnx(_("select() to %s to wait for clock tick timed out"),
+				      rtc_dev_name);
+			} else
+				warn(_("select() to %s to wait for clock tick failed"),
+				     rtc_dev_name);
+			/* Turn off update interrupts */
+			rc = ioctl(rtc_fd, RTC_UIE_OFF, 0);
+			if (rc == -1)
+				warn(_("ioctl() to %s to turn off update interrupts failed"),
+				     rtc_dev_name);
+		} else if (errno == ENOTTY || errno == EINVAL) {
+			/* rtc ioctl interrupts are unimplemented */
+			ret = busywait_for_rtc_clock_tick(ctl, rtc_fd);
+		} else
+			warn(_("ioctl(%d, RTC_UIE_ON, 0) to %s failed"),
+			     rtc_fd, rtc_dev_name);
+	}
+	return ret;
+}
+
+static int read_hardware_clock_rtc(const struct hwclock_control *ctl,
+				   struct tm *tm)
+{
+	int rtc_fd, rc;
+
+	rtc_fd = open_rtc_or_exit(ctl);
+
+	/* Read the RTC time/date, return answer via tm */
+	rc = do_rtc_read_ioctl(rtc_fd, tm);
+
+	return rc;
+}
+
+/*
+ * Set the Hardware Clock to the broken down time <new_broken_time>. Use
+ * ioctls to "rtc" device /dev/rtc.
+ */
+static int set_hardware_clock_rtc(const struct hwclock_control *ctl,
+				  const struct tm *new_broken_time)
+{
+	int rc = -1;
+	int rtc_fd;
+	char *ioctlname;
+
+	rtc_fd = open_rtc_or_exit(ctl);
+
+	ioctlname = "RTC_SET_TIME";
+	rc = ioctl(rtc_fd, RTC_SET_TIME, new_broken_time);
+
+#ifdef __sparc__
+	if (rc == -1) {		/* sparc sbus */
+		struct sparc_rtc_time stm;
+
+		stm.sec = new_broken_time->tm_sec;
+		stm.min = new_broken_time->tm_min;
+		stm.hour = new_broken_time->tm_hour;
+		stm.dom = new_broken_time->tm_mday;
+		stm.month = new_broken_time->tm_mon + 1;
+		stm.year = new_broken_time->tm_year + 1900;
+		stm.dow = new_broken_time->tm_wday + 1;
+
+		ioctlname = "RTCSET";
+		rc = ioctl(rtc_fd, RTCSET, &stm);
+	}
+#endif
+
+	if (rc == -1) {
+		warn(_("ioctl(%s) to %s to set the time failed"),
+			ioctlname, rtc_dev_name);
+		hwclock_exit(ctl, EXIT_FAILURE);
+	}
+
+	if (ctl->verbose)
+		printf(_("ioctl(%s) was successful.\n"), ioctlname);
+
+	return 0;
+}
+
+static int get_permissions_rtc(void)
+{
+	return 0;
+}
+
+static const char *get_device_path(void)
+{
+	return rtc_dev_name;
+}
+
+static struct clock_ops rtc_interface = {
+	N_("Using the rtc interface to the clock."),
+	get_permissions_rtc,
+	read_hardware_clock_rtc,
+	set_hardware_clock_rtc,
+	synchronize_to_clock_tick_rtc,
+	get_device_path,
+};
+
+/* return &rtc if /dev/rtc can be opened, NULL otherwise */
+struct clock_ops *probe_for_rtc_clock(const struct hwclock_control *ctl)
+{
+	const int rtc_fd = open_rtc(ctl);
+
+	if (rtc_fd < 0)
+		return NULL;
+	return &rtc_interface;
+}
+
+#ifdef __alpha__
+/*
+ * Get the Hardware Clock epoch setting from the kernel.
+ */
+int get_epoch_rtc(const struct hwclock_control *ctl, unsigned long *epoch_p)
+{
+	int rtc_fd;
+
+	rtc_fd = open_rtc(ctl);
+	if (rtc_fd < 0) {
+		warn(_("cannot open %s"), rtc_dev_name);
+		return 1;
+	}
+
+	if (ioctl(rtc_fd, RTC_EPOCH_READ, epoch_p) == -1) {
+		warn(_("ioctl(%d, RTC_EPOCH_READ, epoch_p) to %s failed"),
+		     rtc_fd, rtc_dev_name);
+		return 1;
+	}
+
+	if (ctl->verbose)
+		printf(_("ioctl(%d, RTC_EPOCH_READ, epoch_p) to %s succeeded.\n"),
+		       rtc_fd, rtc_dev_name);
+
+	return 0;
+}
+
+/*
+ * Set the Hardware Clock epoch in the kernel.
+ */
+int set_epoch_rtc(const struct hwclock_control *ctl)
+{
+	int rtc_fd;
+	unsigned long epoch;
+
+	epoch = strtoul(ctl->epoch_option, NULL, 10);
+
+	/* There were no RTC clocks before 1900. */
+	if (epoch < 1900 || epoch == ULONG_MAX) {
+		warnx(_("invalid epoch '%s'."), ctl->epoch_option);
+		return 1;
+	}
+
+	rtc_fd = open_rtc(ctl);
+	if (rtc_fd < 0) {
+		warn(_("cannot open %s"), rtc_dev_name);
+		return 1;
+	}
+
+	if (ioctl(rtc_fd, RTC_EPOCH_SET, epoch) == -1) {
+		warn(_("ioctl(%d, RTC_EPOCH_SET, %lu) to %s failed"),
+		     rtc_fd, epoch, rtc_dev_name);
+		return 1;
+	}
+
+	if (ctl->verbose)
+		printf(_("ioctl(%d, RTC_EPOCH_SET, %lu) to %s succeeded.\n"),
+		       rtc_fd, epoch, rtc_dev_name);
+
+	return 0;
+}
+#endif	/* __alpha__ */