source: MondoRescue/branches/3.2/mindi-busybox/libbb/rtc.c@ 3232

/*
 * Common RTC functions
 *
 * Licensed under GPLv2, see file LICENSE in this source tree.
 */

#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 FAST_FUNC rtc_adjtime_is_utc(void)
{
    int utc = 0;
    FILE *f = fopen_for_read(ADJTIME_PATH);

    if (f) {
        char buffer[128];

        while (fgets(buffer, sizeof(buffer), f)) {
            if (strncmp(buffer, "UTC", 3) == 0) {
                utc = 1;
                break;
            }
        }
        fclose(f);
    }

    return utc;
}

int FAST_FUNC 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);
}

void FAST_FUNC rtc_read_tm(struct tm *ptm, int fd)
{
    memset(ptm, 0, sizeof(*ptm));
    xioctl(fd, RTC_RD_TIME, ptm);
    ptm->tm_isdst = -1; /* "not known" */
}

time_t FAST_FUNC rtc_tm2time(struct tm *ptm, int utc)
{
    char *oldtz = oldtz; /* for compiler */
    time_t t;

    if (utc) {
        oldtz = getenv("TZ");
        putenv((char*)"TZ=UTC0");
        tzset();
    }

    t = mktime(ptm);

    if (utc) {
        unsetenv("TZ");
        if (oldtz)
            putenv(oldtz - 3);
        tzset();
    }

    return t;
}