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/* hwclock.c - get and set the hwclock
*
* Copyright 2014 Bilal Qureshi <bilal.jmi@gmail.com>
*
* No standard, but see Documentation/rtc.txt in the linux kernel source..
*
USE_HWCLOCK(NEWTOY(hwclock, ">0(fast)f(rtc):u(utc)l(localtime)t(systz)s(hctosys)r(show)w(systohc)[-ul][!rtsw]", TOYFLAG_SBIN))
config HWCLOCK
bool "hwclock"
default y
help
usage: hwclock [-rswtluf]
Get/set the hardware clock.
-f FILE Use specified device file instead of /dev/rtc0 (--rtc)
-l Hardware clock uses localtime (--localtime)
-r Show hardware clock time (--show)
-s Set system time from hardware clock (--hctosys)
-t Set the system time based on the current timezone (--systz)
-u Hardware clock uses UTC (--utc)
-w Set hardware clock from system time (--systohc)
*/
#define FOR_hwclock
#include "toys.h"
#include <linux/rtc.h>
GLOBALS(
char *f;
)
void hwclock_main()
{
struct timezone tzone;
struct timeval timeval;
struct tm tm;
int fd = -1, utc;
if (FLAG(u)) utc = 1;
else if (FLAG(l)) utc = 0;
else utc = !readfile("/etc/adjtime", toybuf, sizeof(toybuf)) ||
!!strstr(toybuf, "UTC");
if (!FLAG(t)) {
if (!TT.f) TT.f = "/dev/rtc0";
fd = xopen(TT.f, O_WRONLY*FLAG(w));
// Get current time in seconds from rtc device. todo: get subsecond time
if (!FLAG(w)) {
xioctl(fd, RTC_RD_TIME, &tm);
timeval.tv_sec = xmktime(&tm, utc);
timeval.tv_usec = 0; // todo: fixit
}
}
if (FLAG(w) || FLAG(t)) {
if (gettimeofday(&timeval, 0)) perror_exit("gettimeofday failed");
if (!(utc ? gmtime_r : localtime_r)(&timeval.tv_sec, &tm))
error_exit(utc ? "gmtime_r failed" : "localtime_r failed");
}
if (FLAG(w)) {
/* The value of tm_isdst is positive if daylight saving time is in effect,
* zero if it is not and negative if the information is not available.
* todo: so why isn't this negative...? */
tm.tm_isdst = 0;
xioctl(fd, RTC_SET_TIME, &tm);
} else if (FLAG(s)) {
tzone.tz_minuteswest = timezone / 60 - 60 * daylight;
} else if (FLAG(t)) {
// Adjust seconds for timezone and daylight saving time
// extern long timezone is defined in header sys/time.h
tzone.tz_minuteswest = timezone / 60;
if (tm.tm_isdst) tzone.tz_minuteswest -= 60;
if (!utc) timeval.tv_sec += tzone.tz_minuteswest * 60;
} else {
strftime(toybuf, sizeof(toybuf), "%F %T%z", &tm);
xputs(toybuf);
}
if (FLAG(t) || FLAG(s)) {
tzone.tz_dsttime = 0;
if (settimeofday(&timeval, &tzone)) perror_exit("settimeofday failed");
}
xclose(fd);
}
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