Path: utzoo!mnetor!uunet!munnari!kre
From: kre@munnari.oz (Robert Elz)
Newsgroups: comp.protocols.tcp-ip
Subject: Re: WARNING: TOD clock not initialized -- CHECK AND RESET THE DATE!
Message-ID: <1944@munnari.oz>
Date: 3 Jan 88 08:25:17 GMT
References: <8801020627.AA19752@uc.msc.umn.edu> <8801022203.AA25123@uc.msc.umn.edu>
Organization: Comp Sci, Melbourne Uni, Australia
Lines: 57
Summary: An alternative binary patch (for SunOS 3.4), which will work forever

In article <8801020627.AA19752@uc.msc.umn.edu>,
slevy@UC.MSC.UMN.EDU (Stuart Levy) writes:
> I believe I have a fix for this..  Probably the easiest way to
> distribute it without annoying SUN too much is as a binary patch.

Then, In article <8801022203.AA25123@uc.msc.umn.edu>,
slevy@UC.MSC.UMN.EDU (Stuart Levy) writes again:
> I forgot to mention in sending out the SUN kernel binary patch that
> it ONLY works in leap years -- if you just apply the patch, it will break
> in January 1989.

Here's an alternative (binary) patch that will work in both leap years,
and in boring old ordinary years.


# adb -w -k /vmunix /dev/mem
resettodr+0xca?X
	(It should contain 0x536efff4, a subqw #1,a6@(-0xc) instruction.
	If you applied Stuart's patch it will contain 0x4e714e71, 2 nop's
	so put back the subw in both the kernel a.out, and memory)
.?W 536efff4
./W 536efff4
	(next, apply a slightly better fix)
resettodr+0xc0?i
	(it should contain "bnes resettodr+0xca", which we will change to be
	"bnes resettodr+0xce" and avoid the incorrect subw)
.?w 660c
	(now verify that its correct)
.?i
	(and assuming it is "bnes resettodr+0xca", change the running kernel)
./w 660c
$q

I can't verify that this actually fixes the reported problem, but it clearly
does fix a bug, and should have the same effect this year as Stuart's fix,
while not hurting next year.  I used SunOS 3.4 to do this, in case other
versions of SunOS deviate (3.3 is apparently the same), here is the original
section of binary ...

_resettodr+0xa6:                        movw    a6@(-0x10),d0
_resettodr+0xaa:                        moveq   #3,d1
_resettodr+0xac:                        andw    d1,d0
_resettodr+0xae:                        andl    #0xffff,d0
_resettodr+0xb4:                        bnes    _resettodr+0xca
_resettodr+0xb6:                        subqw   #1,a6@(-0xc)
_resettodr+0xba:                        cmpw    #2,a6@(-0xc)
_resettodr+0xc0:                        bnes    _resettodr+0xca	<<<< change this to
_resettodr+0xc2:                        movl    #0x263b80,d0
_resettodr+0xc8:                        bras    _resettodr+0xde
_resettodr+0xca:                        subqw   #1,a6@(-0xc)
_resettodr+0xce:                        moveq   #0,d0		<<<< branch to here
_resettodr+0xd0:                        movw    a6@(-0xc),d0
_resettodr+0xd4:                        lea     _monthsec:l,a0
_resettodr+0xda:                        movl    a0@(-4,d0:l:4),d0
_resettodr+0xde:                        addl    d0,d7

kre