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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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