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/* hwclock.c - get and set the hwclock
*
* Copyright 2014 Bilal Qureshi <bilal.jmi@gmail.com>
*
* No Standard.
*
USE_HWCLOCK(NEWTOY(hwclock, "f(rtc):u(utc)l(localtime)t(systz)w(systohc)s(hctosys)r(show)[!ul][!rs][!rw][!rt][!sw][!st][!wt]", TOYFLAG_USR|TOYFLAG_BIN))
config HWCLOCK
bool "hwclock"
default n
help
usage: hwclock [-r|--show] [-s|--hctosys] [-w|--systohc] [-t|--systz] [-l|--localtime]
[-u|--utc] [-f|--rtc FILE]
-f FILE Use specified device file (e.g. /dev/rtc2) instead of default
-l Assume hardware clock is kept in localtime
-r Show hardware clock time
-s Set system time from hardware clock
-t Set the system time based on the current timezone
-u Assume hardware clock is kept in UTC
-w Set hardware clock from system time
*/
#define FOR_hwclock
#include "toys.h"
#include <linux/rtc.h>
GLOBALS(
char *fname;
int utc;
)
static int rtc_open(char **dev_rtc, int flag)
{
if (!*dev_rtc) {
int fd;
if ((fd = open((*dev_rtc = "/dev/rtc"), flag)) != -1) return fd;
else if ((fd = open((*dev_rtc = "/dev/rtc0"), flag)) != -1) return fd;
else *dev_rtc = "/dev/misc/rtc";
}
return xopen(*dev_rtc, flag);
}
static time_t get_rtc()
{
struct tm time;
time_t tm;
char *ptz_old = NULL;
int fd = rtc_open(&TT.fname, O_RDONLY);
memset(&time, 0, sizeof(time));
xioctl(fd, RTC_RD_TIME, &time);
close(fd);
if (TT.utc) {
ptz_old = getenv("TZ");
if (putenv((char*)"TZ=UTC0")) perror_exit("putenv");
tzset();
}
if ((tm = mktime(&time)) < 0) error_exit("mktime failed");
if (TT.utc) {
if (unsetenv("TZ") < 0) perror_exit("unsetenv");
if (ptz_old && putenv(ptz_old - 3)) perror_exit("putenv");
tzset();
}
return tm;
}
static void set_sysclock_from_hwclock()
{
struct timezone tmzone;
struct timeval tmval;
tmzone.tz_minuteswest = timezone / 60 - 60 * daylight;
tmzone.tz_dsttime = 0;
tmval.tv_sec = get_rtc();
tmval.tv_usec = 0;
if (settimeofday(&tmval, &tmzone) < 0) perror_exit("settimeofday");
}
static void set_hwclock_from_sysclock()
{
struct timeval tmval;
struct tm time;
int fd = rtc_open(&TT.fname, O_WRONLY);
if (gettimeofday(&tmval, NULL) < 0) perror_exit("gettimeofday");
// converting a time value to broken-down UTC time
if (TT. utc && !gmtime_r((time_t*)&tmval.tv_sec, &time))
error_exit("gmtime_r failed");
// converting a time value to a broken-down localtime
else if (!(localtime_r((time_t*)&tmval.tv_sec, &time)))
error_exit("localtime_r failed");
/* 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.
* */
time.tm_isdst = 0;
xioctl(fd, RTC_SET_TIME, &time);
close(fd);
}
static void set_sysclock_timezone()
{
struct timezone tmzone;
struct timeval tmval;
struct tm *pb;
if (gettimeofday(&tmval, NULL) < 0) perror_exit("gettimeofday");
if (!(pb = localtime(&tmval.tv_sec))) error_exit("localtime failed");
// extern long timezone => defined in header sys/time.h
tmzone.tz_minuteswest = timezone / 60;
if (pb->tm_isdst) tmzone.tz_minuteswest -= 60;
tmzone.tz_dsttime = 0; // daylight saving time is not in effect
if (gettimeofday(&tmval, NULL) < 0) perror_exit("gettimeofday");
if (!TT.utc) tmval.tv_sec += tmzone.tz_minuteswest * 60;
if (settimeofday(&tmval, &tmzone) < 0) perror_exit("settimeofday");
}
static void rtc_adjtime()
{
char *line = NULL;
int fd = open("/etc/adjtime", O_RDONLY);
if (fd != -1) {
for (; (line = get_line(fd)); free(line)) {
if (!strncmp(line, "UTC", 3)) {
TT.utc = 1;
break;
}
}
close(fd);
}
}
static void display_hwclock()
{
time_t tm = get_rtc();
char *s, *pctm = ctime(&tm);
if (pctm) {
if ((s = strrchr(pctm, '\n'))) *s = '\0';
xprintf("%s 0.000000 seconds\n", pctm);
} else error_exit("failed to convert a time value to a date & time string");
}
void hwclock_main()
{
(!(toys.optflags & FLAG_u)) ? rtc_adjtime() : (TT.utc = 1); // check for UTC
if (toys.optflags & FLAG_w) set_hwclock_from_sysclock();
else if (toys.optflags & FLAG_s) set_sysclock_from_hwclock();
else if (toys.optflags & FLAG_t) set_sysclock_timezone();
else if ((toys.optflags & FLAG_r) || (toys.optflags & FLAG_l)
|| !*toys.optargs) display_hwclock();
else {
toys.exithelp++;
error_exit("invalid option '%s'", *toys.optargs);
}
}
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