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/*
* 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 <sysexits.h>
#include <sys/ioctl.h>
#include <sys/select.h>
#include <sys/time.h>
#include <time.h>
#include <unistd.h>
#include "clock.h"
#include "nls.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
*/
/* 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)
/* non-sparc stuff */
#if 0
# include <linux/version.h>
/*
* Check if the /dev/rtc interface is available in this version of the
* system headers. 131072 is linux 2.0.0.
*/
# if LINUX_VERSION_CODE >= 131072
# include <linux/mc146818rtc.h>
# endif
#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>) */
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(void)
{
char *fls[] = {
#ifdef __ia64__
"/dev/efirtc",
"/dev/misc/efirtc",
#endif
"/dev/rtc",
"/dev/rtc0",
"/dev/misc/rtc",
NULL
};
char **p;
if (rtc_dev_fd != -1)
return rtc_dev_fd;
/* --rtc option has been given */
if (rtc_dev_name)
rtc_dev_fd = open(rtc_dev_name, O_RDONLY);
else {
for (p = fls; *p; ++p) {
rtc_dev_fd = open(*p, O_RDONLY);
if (rtc_dev_fd < 0
&& (errno == ENOENT || errno == ENODEV))
continue;
rtc_dev_name = *p;
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(void)
{
int rtc_fd = open_rtc();
if (rtc_fd < 0) {
warn(_("open() of %s failed"), rtc_dev_name);
hwclock_exit(EX_OSFILE);
}
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;
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) { /* no sparc, or RTCGET failed */
ioctlname = "RTC_RD_TIME";
rc = ioctl(rtc_fd, RTC_RD_TIME, tm);
}
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.
*/
static int busywait_for_rtc_clock_tick(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 (debug)
printf(_("Waiting in loop for time from %s to change\n"),
rtc_dev_name);
rc = do_rtc_read_ioctl(rtc_fd, &start_time);
if (rc)
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 2;
}
} while (1);
if (rc)
return 3;
return 0;
}
/*
* Same as synchronize_to_clock_tick(), but just for /dev/rtc.
*/
static int synchronize_to_clock_tick_rtc(void)
{
int rtc_fd; /* File descriptor of /dev/rtc */
int ret;
rtc_fd = open_rtc();
if (rtc_fd == -1) {
warn(_("open() of %s failed"), rtc_dev_name);
ret = 1;
} else {
int rc; /* Return code from ioctl */
/* Turn on update interrupts (one per second) */
#if defined(__alpha__) || defined(__sparc__)
/*
* Not all alpha kernels reject RTC_UIE_ON, but probably
* they should.
*/
rc = -1;
errno = EINVAL;
#else
rc = ioctl(rtc_fd, RTC_UIE_ON, 0);
#endif
if (rc == -1 && (errno == ENOTTY || errno == EINVAL)) {
/*
* This rtc device doesn't have interrupt functions.
* 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.
*/
if (debug)
printf(_
("%s does not have interrupt functions. "),
rtc_dev_name);
ret = busywait_for_rtc_clock_tick(rtc_fd);
} else if (rc == 0) {
#ifdef Wait_until_update_interrupt
unsigned long dummy;
/* this blocks until the next update interrupt */
rc = read(rtc_fd, &dummy, sizeof(dummy));
ret = 1;
if (rc == -1)
warn(_
("read() to %s to wait for clock tick failed"),
rtc_dev_name);
else
ret = 0;
#else
/*
* 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 five seconds for the next update
* interrupt
*/
FD_ZERO(&rfds);
FD_SET(rtc_fd, &rfds);
tv.tv_sec = 5;
tv.tv_usec = 0;
rc = select(rtc_fd + 1, &rfds, NULL, NULL, &tv);
ret = 1;
if (rc == -1)
warn(_
("select() to %s to wait for clock tick failed"),
rtc_dev_name);
else if (rc == 0)
warn(_
("select() to %s to wait for clock tick timed out"),
rtc_dev_name);
else
ret = 0;
#endif
/* 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 {
warn(_
("ioctl() to %s to turn on update interrupts "
"failed unexpectedly"), rtc_dev_name);
ret = 1;
}
}
return ret;
}
static int read_hardware_clock_rtc(struct tm *tm)
{
int rtc_fd, rc;
rtc_fd = open_rtc_or_exit();
/* 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 tm *new_broken_time)
{
int rc = -1;
int rtc_fd;
char *ioctlname;
rtc_fd = open_rtc_or_exit();
#ifdef __sparc__
{
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) { /* no sparc, or RTCSET failed */
ioctlname = "RTC_SET_TIME";
rc = ioctl(rtc_fd, RTC_SET_TIME, new_broken_time);
}
if (rc == -1) {
warn(_("ioctl(%s) to %s to set the time failed."),
ioctlname, rtc_dev_name);
hwclock_exit(EX_IOERR);
}
if (debug)
printf(_("ioctl(%s) was successful.\n"), ioctlname);
return 0;
}
static int get_permissions_rtc(void)
{
return 0;
}
static struct clock_ops rtc = {
"/dev interface to clock",
get_permissions_rtc,
read_hardware_clock_rtc,
set_hardware_clock_rtc,
synchronize_to_clock_tick_rtc,
};
/* return &rtc if /dev/rtc can be opened, NULL otherwise */
struct clock_ops *probe_for_rtc_clock(void)
{
int rtc_fd = open_rtc();
if (rtc_fd >= 0)
return &rtc;
if (debug)
warn(_("Open of %s failed"), rtc_dev_name);
return NULL;
}
/*
* Get the Hardware Clock epoch setting from the kernel.
*/
int get_epoch_rtc(unsigned long *epoch_p, int silent)
{
int rtc_fd;
rtc_fd = open_rtc();
if (rtc_fd < 0) {
if (!silent) {
if (errno == ENOENT)
warnx(_
("To manipulate the epoch value in the kernel, we must "
"access the Linux 'rtc' device driver via the device special "
"file %s. This file does not exist on this system."),
rtc_dev_name);
else
warn(_("Unable to open %s"), rtc_dev_name);
}
return 1;
}
if (ioctl(rtc_fd, RTC_EPOCH_READ, epoch_p) == -1) {
if (!silent)
warn(_("ioctl(RTC_EPOCH_READ) to %s failed"),
rtc_dev_name);
return 1;
}
if (debug)
printf(_("we have read epoch %ld from %s "
"with RTC_EPOCH_READ ioctl.\n"), *epoch_p,
rtc_dev_name);
return 0;
}
/*
* Set the Hardware Clock epoch in the kernel.
*/
int set_epoch_rtc(unsigned long epoch)
{
int rtc_fd;
if (epoch < 1900) {
/* kernel would not accept this epoch value
*
* Bad habit, deciding not to do what the user asks just
* because one believes that the kernel might not like it.
*/
warnx(_("The epoch value may not be less than 1900. "
"You requested %ld"), epoch);
return 1;
}
rtc_fd = open_rtc();
if (rtc_fd < 0) {
if (errno == ENOENT)
warnx(_
("To manipulate the epoch value in the kernel, we must "
"access the Linux 'rtc' device driver via the device special "
"file %s. This file does not exist on this system."),
rtc_dev_name);
else
warn(_("Unable to open %s"), rtc_dev_name);
return 1;
}
if (debug)
printf(_("setting epoch to %ld "
"with RTC_EPOCH_SET ioctl to %s.\n"), epoch,
rtc_dev_name);
if (ioctl(rtc_fd, RTC_EPOCH_SET, epoch) == -1) {
if (errno == EINVAL)
warnx(_("The kernel device driver for %s "
"does not have the RTC_EPOCH_SET ioctl."),
rtc_dev_name);
else
warn(_("ioctl(RTC_EPOCH_SET) to %s failed"),
rtc_dev_name);
return 1;
}
return 0;
}
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