blob: 1d313e3b68c95d8a6b68f046ddc5cc6eaa5dc662 [file] [log] [blame]
/* 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_USR|TOYFLAG_BIN))
config HWCLOCK
bool "hwclock"
default y
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;
sprintf(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) {
sprintf(toybuf, "/dev/%s", node->name);
TT.fname = toybuf;
return DIRTREE_ABORT;
}
}
return 0;
}
void hwclock_main()
{
struct timezone tzone;
struct timeval timeval;
struct tm tm;
time_t time;
int fd = -1;
// check for Grenich Mean Time
if (toys.optflags & FLAG_u) TT.utc = 1;
else {
FILE *fp;
char *s = 0;
for (fp = fopen("/etc/adjtime", "r");
fp && getline(&s, (void *)toybuf, fp)>0;
free(s), s = 0) TT.utc += !strncmp(s, "UTC", 3);
if (fp) fclose(fp);
}
if (!(toys.optflags&FLAG_t)) {
int w = toys.optflags & FLAG_w, flag = O_WRONLY*w;
// Open /dev/rtc (if your system has no /dev/rtc symlink, search for it).
if (!TT.fname && (fd = open("/dev/rtc", flag)) == -1) {
dirtree_read("/sys/class/rtc", rtc_find);
if (!TT.fname) TT.fname = "/dev/misc/rtc";
}
if (fd == -1) fd = xopen(TT.fname, flag);
// Get current time in seconds from rtc device. todo: get subsecond time
if (!w) {
char *s = s;
xioctl(fd, RTC_RD_TIME, &tm);
if (TT.utc) s = xtzset("UTC0");
if ((time = mktime(&tm)) < 0) error_exit("mktime failed");
if (TT.utc) {
free(xtzset(s));
free(s);
}
}
}
if (toys.optflags & (FLAG_w|FLAG_t)) {
if (gettimeofday(&timeval, 0)) perror_exit("gettimeofday failed");
if (!(TT.utc ? gmtime_r : localtime_r)(&timeval.tv_sec, &tm))
error_exit(TT.utc ? "gmtime_r failed" : "localtime_r failed");
}
if (toys.optflags & 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 (toys.optflags & FLAG_s) {
tzone.tz_minuteswest = timezone / 60 - 60 * daylight;
timeval.tv_sec = time;
timeval.tv_usec = 0; // todo: fixit
} else if (toys.optflags & 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 (!TT.utc) timeval.tv_sec += tzone.tz_minuteswest * 60;
} else {
char *c = ctime(&time), *s = strrchr(c, '\n');
if (s) *s = '\0';
// TODO: implement this.
xprintf("%s 0.000000 seconds\n", c);
}
if (toys.optflags & (FLAG_t|FLAG_s)) {
tzone.tz_dsttime = 0;
if (settimeofday(&timeval, &tzone)) perror_exit("settimeofday failed");
}
if (fd != -1) close(fd);
}