Author: ian
Date: Sun Jul 23 21:28:00 2017
New Revision: 321400
URL: https://svnweb.freebsd.org/changeset/base/321400
Log:
Add common code to support realtime clocks that store year without century.
Most realtime clocks store the year as 2 BCD digits. Some add a century bit
to extend the range another hundred years. Every clock driver has its own
code to determine the century and pass a full year value to clock_ct_to_ts().
Now clock drivers can just convert BCD to bin and store the result in the
clocktime struct and let the common code figure out the century. Clocks
with a century bit can just add 100 to year if the century bit is on.
Modified:
head/sys/kern/subr_clock.c
Modified: head/sys/kern/subr_clock.c
==============================================================================
--- head/sys/kern/subr_clock.c Sun Jul 23 20:41:58 2017 (r321399)
+++ head/sys/kern/subr_clock.c Sun Jul 23 21:28:00 2017 (r321400)
@@ -142,18 +142,27 @@ clock_ct_to_ts(struct clocktime *ct, struct timespec *
{
int i, year, days;
- year = ct->year;
-
if (ct_debug) {
printf("ct_to_ts(");
print_ct(ct);
printf(")");
}
+ /*
+ * Many realtime clocks store the year as 2-digit BCD; pivot on 70 to
+ * determine century. Some clocks have a "century bit" and drivers do
+ * year += 100, so interpret values between 70-199 as relative to 1900.
+ */
+ year = ct->year;
+ if (year < 70)
+ year += 2000;
+ else if (year < 200)
+ year += 1900;
+
/* Sanity checks. */
if (ct->mon < 1 || ct->mon > 12 || ct->day < 1 ||
ct->day > days_in_month(year, ct->mon) ||
- ct->hour > 23 || ct->min > 59 || ct->sec > 59 ||
+ ct->hour > 23 || ct->min > 59 || ct->sec > 59 || year < 1970 ||
(sizeof(time_t) == 4 && year > 2037)) { /* time_t overflow */
if (ct_debug)
printf(" = EINVAL\n");
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