busybox/libbb/rtc.c
Denys Vlasenko 5e3b14069e hwclock: make it report system/rtc clock difference
function                                             old     new   delta
rtc_tm2time                                            -      89     +89
read_rtc                                              23      86     +63
rtc_read_tm                                            -      49     +49
hwclock_main                                         428     466     +38
rtcwake_main                                         453     477     +24
rtc_read_time                                        142       -    -142
------------------------------------------------------------------------------
(add/remove: 2/1 grow/shrink: 3/0 up/down: 263/-142)          Total: 121 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2010-01-06 22:43:39 +01:00

91 lines
1.4 KiB
C

/*
* Common RTC functions
*
* Licensed under GPLv2, see file LICENSE in this tarball for details.
*/
#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)) {
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);
}
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 *tm, int fd)
{
memset(tm, 0, sizeof(*tm));
xioctl(fd, RTC_RD_TIME, tm);
tm->tm_isdst = -1; /* "not known" */
}
time_t FAST_FUNC rtc_tm2time(struct tm *tm, int utc)
{
char *oldtz = oldtz; /* for compiler */
time_t t;
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;
}