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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)w(systohc)s(hctosys)r(show)[-ul][!rtsw]", TOYFLAG_USR|TOYFLAG_BIN))
config HWCLOCK
bool "hwclock"
default n
help
usage: hwclock [-rswtluf]
-f FILE Use specified device file instead of /dev/rtc (--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 *fname;
int utc;
)
static int rtc_find(struct dirtree* node)
{
FILE *fp;
if (!node->parent) return DIRTREE_RECURSE;
snprintf(toybuf, sizeof(toybuf), "/sys/class/rtc/%s/hctosys", node->name);
fp = fopen(toybuf, "r");
if (fp) {
int hctosys = 0, items = fscanf(fp, "%d", &hctosys);
fclose(fp);
if (items == 1 && hctosys == 1) {
snprintf(toybuf, sizeof(toybuf), "/dev/%s", node->name);
TT.fname = toybuf;
return DIRTREE_ABORT;
}
}
return 0;
}
// Your system should have a /dev/rtc symlink. If your system is misconfigured,
// search /sys/class/rtc for RTC system clock set from, then try /dev/misc/rtc.
static int rtc_open(int flag)
{
if (!TT.fname) {
int fd;
if ((fd = open((TT.fname = "/dev/rtc"), flag)) != -1) return fd;
TT.fname = 0;
dirtree_read("/sys/class/rtc", rtc_find);
if (TT.fname) return xopen(TT.fname, flag);
TT.fname = "/dev/misc/rtc";
}
return xopen(TT.fname, flag);
}
// Get current time in seconds from rtc device. We could get subsecond time by
// waiting for next time change, but haven't implemented that yet.
static time_t get_rtc_seconds()
{
struct tm time;
time_t tm;
char *ptz_old = ptz_old;
int fd = rtc_open(O_RDONLY);
xioctl(fd, RTC_RD_TIME, &time);
close(fd);
if (TT.utc) ptz_old = xtzset("UTC0");
if ((tm = mktime(&time)) < 0) error_exit("mktime failed");
if (TT.utc) {
free(xtzset(ptz_old));
free(ptz_old);
}
return tm;
}
void hwclock_main()
{
struct timezone tzone;
struct timeval timeval;
// check for Grenich Mean Time
if (toys.optflags & FLAG_u) TT.utc = 1;
else {
FILE *fp = fopen("/etc/adjtime", "r");
if (fp) {
for (;;) {
char *line = 0;
if (getline(&line, (void *)toybuf, fp) <= 0) break;
TT.utc += !strncmp(line, "UTC", 3);
free(line);
}
fclose(fp);
}
}
if (toys.optflags & FLAG_w) {
struct tm tm;
int fd = rtc_open(O_WRONLY);
if (gettimeofday(&timeval, 0)) perror_exit("gettimeofday");
if ((TT.utc ? gmtime_r : localtime_r)(&timeval.tv_sec, &tm))
error_exit("timeval");
/* The value of tm_isdst will positive if daylight saving time is in effect,
* zero if it is not and negative if the information is not available.
* */
tm.tm_isdst = 0;
xioctl(fd, RTC_SET_TIME, &time);
close(fd);
} else if (toys.optflags & FLAG_s) {
tzone.tz_minuteswest = timezone / 60 - 60 * daylight;
tzone.tz_dsttime = 0;
timeval.tv_sec = get_rtc_seconds();
timeval.tv_usec = 0;
if (settimeofday(&timeval, &tzone) < 0) perror_exit("settimeofday");
} else if (toys.optflags & FLAG_t) {
struct tm *pb;
if (gettimeofday(&timeval, NULL) < 0) perror_exit("gettimeofday");
if (!(pb = localtime(&timeval.tv_sec))) error_exit("localtime failed");
// extern long timezone is defined in header sys/time.h
tzone.tz_minuteswest = timezone / 60;
if (pb->tm_isdst) tzone.tz_minuteswest -= 60;
tzone.tz_dsttime = 0; // daylight saving time is not in effect
if (gettimeofday(&timeval, NULL) < 0) perror_exit("gettimeofday");
if (!TT.utc) timeval.tv_sec += tzone.tz_minuteswest * 60;
if (settimeofday(&timeval, &tzone) < 0) perror_exit("settimeofday");
} else {
time_t tm = get_rtc_seconds();
char *pctm = ctime(&tm), *s = strrchr(pctm, '\n');
if (s) *s = '\0';
// TODO: implement this.
xprintf("%s 0.000000 seconds\n", pctm);
}
}
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