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hwclock: make it report system/rtc clock difference

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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>
This commit is contained in:
Denys Vlasenko
2010-01-06 22:43:39 +01:00
parent 695fa51c80
commit 5e3b14069e
4 changed files with 53 additions and 24 deletions
Download Patch File Download Diff File Expand all files Collapse all files

44
util-linux/hwclock.c
View File

@ -20,34 +20,54 @@
static const char *rtcname;
static time_t read_rtc(int utc)
static time_t read_rtc(struct timeval *sys_tv, int utc)
{
time_t ret;
struct tm tm;
int fd;
int before;
fd = rtc_xopen(&rtcname, O_RDONLY);
ret = rtc_read_time(fd, utc);
rtc_read_tm(&tm, fd);
before = tm.tm_sec;
while (1) {
rtc_read_tm(&tm, fd);
gettimeofday(sys_tv, NULL);
if (before != tm.tm_sec)
break;
}
if (ENABLE_FEATURE_CLEAN_UP)
close(fd);
return ret;
return rtc_tm2time(&tm, utc);
}
static void show_clock(int utc)
{
//struct tm *ptm;
struct timeval sys_tv;
time_t t;
long diff;
char *cp;
t = read_rtc(utc);
//ptm = localtime(&t); /* Sets 'tzname[]' */
t = read_rtc(&sys_tv, utc);
cp = ctime(&t);
strchrnul(cp, '\n')[0] = '\0';
//printf("%s 0.000000 seconds %s\n", cp, utc ? "" : (ptm->tm_isdst ? tzname[1] : tzname[0]));
/* 0.000000 stand for unimplemented difference between RTC and system clock */
printf("%s 0.000000 seconds\n", cp);
diff = sys_tv.tv_sec - t;
if (diff < 0 /*&& tv.tv_usec != 0*/) {
/* Why? */
/* diff >= 0 is ok: diff < 0, can't just use tv.tv_usec: */
/* 45.520820 43.520820 */
/* - 44.000000 - 45.000000 */
/* = 0.520820 = -1.479180, not -2.520820! */
diff++;
/* should be 1000000 - tv.tv_usec, but then we must check tv.tv_usec != 0 */
sys_tv.tv_usec = 999999 - sys_tv.tv_usec;
}
printf("%s %ld.%06lu seconds\n", cp, diff, (unsigned long)sys_tv.tv_usec);
}
static void to_sys_clock(int utc)
@ -58,7 +78,7 @@ static void to_sys_clock(int utc)
tz.tz_minuteswest = timezone/60 - 60*daylight;
tz.tz_dsttime = 0;
tv.tv_sec = read_rtc(utc);
tv.tv_sec = read_rtc(NULL, utc);
tv.tv_usec = 0;
if (settimeofday(&tv, &tz))
bb_perror_msg_and_die("settimeofday() failed");
@ -79,15 +99,15 @@ static void from_sys_clock(int utc)
gettimeofday(&tv, NULL);
t = tv.tv_sec;
rem_usec = 1000000 - tv.tv_usec;
if (rem_usec < 1024) {
/* Less than 1ms to next second. Good enough */
small_rem:
tv.tv_sec++;
t++;
}
/* Prepare tm */
t = tv.tv_sec;
if (utc)
gmtime_r(&t, &tm); /* may read /etc/xxx (it takes time) */
else