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hwclock: remove 1994 Award BIOS workaround 

Remove the 1994 Award BIOS bug workaround as
previously discussed more than two years ago:
http://marc.info/?l=util-linux-ng&m=141682406902804&w=2

* sys-utils/hwclock.c: remove badyear option
* sys-utils/hwclock.h: same
* sys-utils/hwclock.8.in: same

Signed-off-by: J William Piggott <elseifthen@gmx.com>
This commit is contained in:
J William Piggott 2017-03-24 11:03:16 -04:00 committed by Karel Zak
parent a837b3bdf3
commit f6374e1fb3
3 changed files with 1 additions and 100 deletions
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38
sys-utils/hwclock.8.in
View File

@ -245,42 +245,6 @@ Display help text and exit.
.RI "Override the default " @ADJTIME_PATH@ " file path."
.
.TP
.B \-\-badyear
Indicate that the Hardware Clock is incapable of storing years outside
the range 1994-1999. There is a problem in some BIOSes (almost all
Award BIOSes made between 4/26/94 and 5/31/95) wherein they are unable
to deal with years after 1999. If one attempts to set the year-of-century
value to something less than 94 (or 95 in some cases), the value that
actually gets set is 94 (or 95). Thus, if you have one of these machines,
.B \%hwclock
cannot set the year after 1999 and cannot use the value of the clock as
the true time in the normal way.
.sp
To compensate for this (without your getting a BIOS update, which would
definitely be preferable), always use
.B \%\-\-badyear
if you have one of these machines. When
.B \%hwclock
knows it's working with a brain-damaged clock, it ignores the year part of
the Hardware Clock value and instead tries to guess the year based on the
last calibrated date in the adjtime file, by assuming that date is
within the past year. For this to work, you had better do a
.B \%hwclock\ \-\-set
or
.B \%hwclock\ \-\-systohc
at least once a year!
.sp
Though
.B \%hwclock
ignores the year value when it reads the Hardware Clock, it sets the
year value when it sets the clock. It sets it to 1995, 1996, 1997, or
1998, whichever one has the same position in the leap year cycle as
the true year. That way, the Hardware Clock inserts leap days where
they belong. Again, if you let the Hardware Clock run for more than a
year without setting it, this scheme could be defeated and you could
end up losing a day.
.
.TP
.BI \%\-\-date= date_string
This option must be used with the
.B \-\-set
@ -294,7 +258,7 @@ functions, otherwise it is ignored.
.B "hwclock\ \-\-predict\ \-\-date='2525-08-14\ 07:11:05'"
.PP
The argument must be in local time, even if you keep your Hardware Clock in
UTC. See the
UTC. See the
.B \%\-\-localtime
option. Therefore, the argument should not include any timezone information.
It also should not be a relative time like "+5 minutes", because

62
sys-utils/hwclock.c
View File

@ -125,48 +125,6 @@ struct adjtime {
*/
};
/*
* Almost all Award BIOS's made between 04/26/94 and 05/31/95 have a nasty
* bug limiting the RTC year byte to the range 94-99. Any year between 2000
* and 2093 gets changed to 2094, every time you start the system.
*
* With the --badyear option, we write the date to file and hope that the
* file is updated at least once a year. I recommend putting this command
* "hwclock --badyear" in the monthly crontab, just to be safe.
*
* -- Dave Coffin 11/12/98
*/
static void write_date_to_file(struct tm *tm)
{
FILE *fp;
if ((fp = fopen(_PATH_LASTDATE, "w"))) {
fprintf(fp, "%02d.%02d.%04d\n", tm->tm_mday, tm->tm_mon + 1,
tm->tm_year + 1900);
if (close_stream(fp) != 0)
warn(_("cannot write %s"), _PATH_LASTDATE);
} else
warn(_("cannot write %s"), _PATH_LASTDATE);
}
static void read_date_from_file(struct tm *tm)
{
int last_mday, last_mon, last_year;
FILE *fp;
if ((fp = fopen(_PATH_LASTDATE, "r"))) {
if (fscanf(fp, "%d.%d.%d\n", &last_mday, &last_mon, &last_year)
== 3) {
tm->tm_year = last_year - 1900;
if ((tm->tm_mon << 5) + tm->tm_mday <
((last_mon - 1) << 5) + last_mday)
tm->tm_year++;
}
fclose(fp);
}
write_date_to_file(tm);
}
/*
* time_t to timeval conversion.
*/
@ -398,9 +356,6 @@ read_hardware_clock(const struct hwclock_control *ctl,
if (err)
return err;
if (ctl->badyear)
read_date_from_file(&tm);
if (ctl->debug)
printf(_
("Time read from Hardware Clock: %4d/%.2d/%.2d %02d:%02d:%02d\n"),
@ -438,17 +393,6 @@ set_hardware_clock(const struct hwclock_control *ctl, const time_t newtime)
if (ctl->testing)
printf(_("Clock not changed - testing only.\n"));
else {
if (ctl->badyear) {
/*
* Write the real year to a file, then write a fake
* year between 1995 and 1998 to the RTC. This way,
* Award BIOS boots on 29 Feb 2000 thinking that
* it's 29 Feb 1996.
*/
write_date_to_file(&new_broken_time);
new_broken_time.tm_year =
95 + ((new_broken_time.tm_year + 1) & 3);
}
ur->set_hardware_clock(ctl, &new_broken_time);
}
}
@ -1323,7 +1267,6 @@ static void usage(const struct hwclock_control *ctl, const char *fmt, ...)
#endif
fprintf(usageto, _(
" --directisa access the ISA bus directly instead of %s\n"
" --badyear ignore RTC's year because the BIOS is broken\n"
" --date <time> specifies the time to which to set the hardware clock\n"
" --epoch <year> specifies the year which is the beginning of the\n"
" hardware clock's epoch value\n"), _PATH_RTC_DEV);
@ -1377,7 +1320,6 @@ int main(int argc, char **argv)
/* Long only options. */
enum {
OPT_ADJFILE = CHAR_MAX + 1,
OPT_BADYEAR,
OPT_DATE,
OPT_DIRECTISA,
OPT_EPOCH,
@ -1418,7 +1360,6 @@ int main(int argc, char **argv)
#endif
{ "noadjfile", no_argument, NULL, OPT_NOADJFILE },
{ "localtime", no_argument, NULL, OPT_LOCALTIME },
{ "badyear", no_argument, NULL, OPT_BADYEAR },
{ "directisa", no_argument, NULL, OPT_DIRECTISA },
{ "test", no_argument, NULL, OPT_TEST },
{ "date", required_argument, NULL, OPT_DATE },
@ -1528,9 +1469,6 @@ int main(int argc, char **argv)
case OPT_LOCALTIME:
ctl.local_opt = 1; /* --localtime */
break;
case OPT_BADYEAR:
ctl.badyear = 1;
break;
case OPT_DIRECTISA:
ctl.directisa = 1;
break;

1
sys-utils/hwclock.h
View File

@ -44,7 +44,6 @@ struct hwclock_control {
#endif
noadjfile:1,
local_opt:1,
badyear:1,
directisa:1,
testing:1,
systz:1,