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Use more AI to predict initial/final isdst,

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latest isdst  preffered.
This commit is contained in:
Andrey A. Chernov 1995-03-26 22:51:51 +00:00
parent 266e938a21
commit 73cab1a3bc
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=7398
1 changed files with 37 additions and 19 deletions
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56
sbin/adjkerntz/adjkerntz.c
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@ -1,5 +1,5 @@
/*
* Copyright (C) 1993, 1994 by Andrew A. Chernov, Moscow, Russia.
* Copyright (C) 1993, 1994, 1995 by Andrey A. Chernov, Moscow, Russia.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
@ -26,12 +26,12 @@
#ifndef lint
char copyright[] =
"@(#)Copyright (C) 1993 by Andrew A. Chernov, Moscow, Russia.\n\
"@(#)Copyright (C) 1993, 1994, 1995 by Andrey A. Chernov, Moscow, Russia.\n\
All rights reserved.\n";
#endif /* not lint */
/*
* Andrew A. Chernov <ache@astral.msk.su> Dec 20 1993
* Andrey A. Chernov <ache@astral.msk.su> Dec 20 1993
*
* Fix kernel time value if machine run wall CMOS clock
* (and /etc/wall_cmos_clock file present)
@ -72,6 +72,7 @@ int main(argc, argv)
long offset, utcsec, localsec, diff;
time_t initial_sec, final_sec;
int ch, init = -1;
int initial_isdst = -1, final_isdst, looping;
int disrtcset, need_restore = 0;
sigset_t mask, emask;
@ -118,6 +119,19 @@ int main(argc, argv)
(void) sigprocmask(SIG_BLOCK, &mask, NULL);
(void) signal(SIGTERM, fake);
diff = 0;
stv = NULL;
stz = NULL;
looping = 0;
mib[0] = CTL_MACHDEP;
mib[1] = CPU_ADJKERNTZ;
len = sizeof(kern_offset);
if (sysctl(mib, 2, &kern_offset, &len, NULL, 0) == -1) {
syslog(LOG_ERR, "sysctl(get_offset): %m");
return 1;
}
/****** Critical section, do all things as fast as possible ******/
/* get local CMOS clock and possible kernel offset */
@ -128,13 +142,18 @@ int main(argc, argv)
/* get the actual local timezone difference */
initial_sec = tv.tv_sec;
recalculate:
local = *localtime(&initial_sec);
if (diff == 0)
initial_isdst = local.tm_isdst;
utc = *gmtime(&initial_sec);
local.tm_isdst = utc.tm_isdst = initial_isdst;
/* calculate local CMOS diff from GMT */
utcsec = timelocal(&utc);
localsec = timelocal(&local);
utcsec = mktime(&utc);
localsec = mktime(&local);
if (utcsec == -1 || localsec == -1) {
/*
* XXX user can only control local time, and it is
@ -153,17 +172,6 @@ int main(argc, argv)
fprintf(stderr, "Initial offset: %ld secs\n", offset);
#endif
mib[0] = CTL_MACHDEP;
mib[1] = CPU_ADJKERNTZ;
len = sizeof(kern_offset);
if (sysctl(mib, 2, &kern_offset, &len, NULL, 0) == -1) {
syslog(LOG_ERR, "sysctl(get_offset): %m");
return 1;
}
stv = NULL;
stz = NULL;
/* correct the kerneltime for this diffs */
/* subtract kernel offset, if present, old offset too */
@ -175,15 +183,25 @@ int main(argc, argv)
#endif
/* Yet one step for final time */
final_sec = tv.tv_sec + diff;
final_sec = initial_sec + diff;
/* get the actual local timezone difference */
local = *localtime(&final_sec);
final_isdst = diff < 0 ? initial_isdst : local.tm_isdst;
if (diff > 0 && initial_isdst != final_isdst) {
if (looping)
goto bad_final;
looping++;
initial_isdst = final_isdst;
goto recalculate;
}
utc = *gmtime(&final_sec);
local.tm_isdst = utc.tm_isdst = final_isdst;
utcsec = timelocal(&utc);
localsec = timelocal(&local);
utcsec = mktime(&utc);
localsec = mktime(&local);
if (utcsec == -1 || localsec == -1) {
bad_final:
/*
* XXX as above. The user has even less control,
* but perhaps we never get here.