#! /bin/sh

# adjdata -- works on /etc/adjtime data, used by clock(8) [linux]
# $Id: adjdata,v 1.3 1998/07/12 18:21:42 cdua Exp cdua $
# Carlos Duarte, 960807/960825

# adjdata
# 
# This script/database, keeps pairs of
# 
# 	system date
# 	real date
# 
# and fixes system and CMOS time, as updating the correcting value
# of the first field of /etc/adjtime
# 
# 
# FORMAT: 
# 
# 	the lines from beggining thru the first line began with
# 	######## (8 #s) is a sh(1) script, from that line thru
# 	end is a data base.
# 
# 	the data base, have the format: 
# 
# 	lines beg with a # are comments
# 	blank lines are ignored
# 
# 	each line contains a date on locale format
# 	the dates came in this order, system date, real date, ...
# 	as
# 		system date 1
# 		real date 1
# 		system date 2
# 		real date 2
# 		...
# 
# DESCRIPTION
# 	
# 	to operate, two lines (i.e. on system+real date) must be present
# 
# 	so: sh adjdata init, take care of it
# 
# 	then, the user is asked for the real date, as fast as it can,
# 	it asks system for system date, now it gots the real and the
# 	system date taken at the (almost) same time
# 
# 	the system and CMOS clock are setted with real date, and
# 	the difference between the real elapsed time and system
# 	elapsed time is computed; 
# 
# 	with that difference value, the first field of /etc/adjtime
# 	will be adjusted
# 
# 

inpdate()
{
	local date
	local ans

	while : 
	do

		cat 1>&2 << eof
This is current system date: `date` 
Input REAL date on the same format ...
>> note: you need not give all values, you may give only some fields,
>>       like the hours:minutes:seconds one
>>       or the hours/min/seconds alone

>> Try whatever you want, if an error occurs you can try again
>> if you want to abort press ^C

eof

		echo 1>&2 -n Input the REAL date:" "
		read date || exit 2
		date -d"$date" +%c 1>&2 && {
			date 
			date -d"$date" +%c
			return 0
		}
	done
}

help()
{
	cat << eof
Usage: $0 [init|info|update]
       $0 

With no args, is the same as update, and update the system time
as well info on /etc/adjtime

With init, sets this database, to current values, i.e. forget past

eof
}

#----
# Date: Fri, 11 Oct 91 11:22:36 edt
# From: friedman@gnu.ai.mit.edu
# To: bfox@gnu.ai.mit.edu

# A replacement for basename(1).  Not all the systems I use have this
# program.  Usage: basename [path] {extension}
function basename ()
{
 local path="$1"
 local suffix="$2"
 local tpath="${path%/}"

    # Strip trailing '/' characters from path (unusual that this should
    # ever occur, but basename(1) seems to deal with it.)
    while [ "${tpath}" != "${path}" ]; do
       tpath="${path}"
       path="${tpath%/}"
    done

    path="${path##*/}"       # Strip off pathname
    echo ${path%${suffix}}   # Also strip off extension, if any.
}
#----

install()
{
	local dest=/etc/`basename $1`

# 	cp -uvdpf $1 $dest && \
# 	chown root $dest && \
# 	chgrp root $dest && \
# 	chmod -x $dest

	[ $0 -nt $dest ] && ln -sf $0 $dest
}

# main()

case x"$1" in

	x | update)
		;;

	xinit)
		date | sed 's/.*/&\
&/' >> $0
		exit 0
		;;

	xinstall)
		install $0
		exit
		;;

	*)
		help
		exit 1
		;;
esac

# inpdate | tee -a $0 | { 
# 	read sys; 
# 	read real; 
# 	date -s"$real"
# 	clock -w
# }

inpdate | {
	read sys 
	read real
	date -s"$real" 
	clock -w 
	echo $sys >>$0
	echo $real >>$0
}

# sed -n '
# 
# 1,/^########/d
# 
# /^#/d
# y/	/ /
# /^ *$/d
# 
# H
# 
# ${
# 	x
# 	:a
# 	s/^.*\n\([^\n]*\n[^\n]*\n[^\n]*\)$/\1/p
# }'

	sed '1,/^########/d;/^#/d;y/	/ /;/^ *$/d' $0 | \
	tail -n 3 | \
	date -f - +'%s' | \
	cat - /etc/adjtime | sed '

1s/.*/tsys1=&\
treal1=&/
2s/^/tsys2=/
3s/^/treal2=/
4{;s/^/correct=/;y/	/ /;s/ .*//;}

$a\
	scale=6\
	dsys=tsys2-tsys1\
	dreal=treal2-treal1\
	diff=dsys-dreal\
	if(diff){\
		elaps=dreal/(86400) /* 86400 = 24*60*60 */\
		correct -= diff/elaps\
	}\
	correct\
	quit

' | {
	echo -e 's/^[^ ]*/'`bc -l`'/\nwq'
} | ed /etc/adjtime 2> /dev/null

#clock -a

exit 0

######## 

Wed Aug  7 17:20:24  1996
Wed Aug  7 17:20:24  1996
Wed Aug  7 17:28:45  1996
Wed Aug 07 17:28:45  1996
Wed Aug  7 18:18:44  1996
Wed Aug 07 18:19:10  1996
Wed Aug  7 18:20:42  1996
Wed Aug 07 18:20:49  1996
Wed Aug 7 19:26:18 1996
Wed Aug 07 19:26:00 1996
Wed Aug  7 19:28:45  1996
Wed Aug  7 19:28:45  1996
Fri Aug 9 23:11:14 1996
Fri Aug 09 23:11:20 1996
Tue Aug 13 21:14:27 1996
Tue Aug 13 21:14:20 1996
Fri Aug 16 21:45:49 1996
Fri Aug 16 21:45:50 1996
Sun Aug 25 00:58:17 1996
Sun Aug 25 00:58:20 1996
Sun Aug 25 01:58:45  1996
Sun Aug 25 01:58:45  1996
Mon Aug 26 12:50:21 1996
Mon Aug 26 12:50:20 1996
Fri Aug 30 22:05:38 1996
Fri Aug 30 22:05:40 1996
Thu Sep 12 13:00:59 1996
Thu Sep 12 13:01:00 1996
Sun Feb 9 14:34:24 MET 1997
Sun Feb 09 17:24:30 MET 1997
Mon Feb 10 00:17:58 MET 1997
Mon Feb 10 03:11:05 MET 1997
Mon Feb 10 04:04:21 MET 1997
Mon Feb 10 03:12:55 MET 1997
Tue Feb 11 02:10:12 MET 1997
Tue Feb 11 03:13:12 MET 1997
Mon Feb 10 20:23:56 MET 1997
Mon Feb 10 20:23:55 MET 1997
Mon Feb 10 23:06:18 MET 1997
Mon Feb 10 23:05:57 MET 1997
Mon Feb 10 23:06:38 MET 1997
Tue Feb 11 02:56:55 MET 1997
Tue Feb 11 14:49:22 MET 1997
Tue Feb 11 14:30:45 MET 1997
Tue Feb 11 17:12:46 MET 1997
Tue Feb 11 16:43:05 MET 1997
Tue Feb 11 21:30:08 MET 1997
Tue Feb 11 19:52:10 MET 1997
Wed Feb 12 03:06:46 MET 1997
Wed Feb 12 02:32:45 MET 1997
Wed Feb 12 05:25:02 MET 1997
Wed Feb 12 17:05:50 MET 1997
Thu Feb 13 10:25:38 MET 1997
Thu Feb 13 21:55:25 MET 1997
Sat Feb 15 13:48:22 MET 1997
Sat Feb 15 15:41:10 MET 1997


Sat Feb 15 18:40:49 MET 1997
Thu Feb 13 15:48:15 MET 1997
Sat Feb 8 14:18:36 MET 1997
Thu Feb 13 17:20:50 MET 1997
Sat May 2 19:10:18 MET DST 1998
Fri Feb 14 00:45:00 MET 1997
Fri Feb 14 01:12:08 MET 1997
Fri Feb 14 01:15:10 MET 1997
Fri Feb 14 15:21:44 MET 1997
Sat Feb 15 20:45:00 MET 1997