hush/libbb/rtc.c

89 lines
1.3 KiB
C

/*
* Common RTC functions
*/
#include "libbb.h"
#include "rtc_.h"
#if ENABLE_FEATURE_HWCLOCK_ADJTIME_FHS
# define ADJTIME_PATH "/var/lib/hwclock/adjtime"
#else
# define ADJTIME_PATH "/etc/adjtime"
#endif
int rtc_adjtime_is_utc(void)
{
int utc = 0;
FILE *f = fopen(ADJTIME_PATH, "r");
if (f) {
RESERVE_CONFIG_BUFFER(buffer, 128);
while (fgets(buffer, sizeof(buffer), f)) {
int len = strlen(buffer);
while (len && isspace(buffer[len - 1]))
len--;
buffer[len] = 0;
if (strncmp(buffer, "UTC", 3) == 0) {
utc = 1;
break;
}
}
fclose(f);
RELEASE_CONFIG_BUFFER(buffer);
}
return utc;
}
int rtc_xopen(const char **default_rtc, int flags)
{
int rtc;
if (!*default_rtc) {
*default_rtc = "/dev/rtc";
rtc = open(*default_rtc, flags);
if (rtc >= 0)
return rtc;
*default_rtc = "/dev/rtc0";
rtc = open(*default_rtc, flags);
if (rtc >= 0)
return rtc;
*default_rtc = "/dev/misc/rtc";
}
return xopen(*default_rtc, flags);
}
time_t rtc_read_time(int fd, int utc)
{
struct tm tm;
char *oldtz = 0;
time_t t = 0;
memset(&tm, 0, sizeof(struct tm));
xioctl(fd, RTC_RD_TIME, &tm);
tm.tm_isdst = -1; /* not known */
if (utc) {
oldtz = getenv("TZ");
putenv((char*)"TZ=UTC0");
tzset();
}
t = mktime(&tm);
if (utc) {
unsetenv("TZ");
if (oldtz)
putenv(oldtz - 3);
tzset();
}
return t;
}