#!/bin/rc

dosdisk=`{ls /dev/sd??/dos >[2]/dev/null | sed 1q | sed 's!.*/(.*)/dos!\1!'}
if(~ $#dosdisk 0 || ! c: || ! test -f /n/c:/autoexec.bat || ! test -f /n/c:/config.sys) {
	echo 'Could not find autoexec.bat or config.sys on the first FAT disk.'
	exit bad
}

for (i in autoexec config msdos)
	if(test -f /n/c:/$i.p9) {
		echo 'A Plan 9 backup already exists; will not edit system files again.'
		exit bad
	}

for (i in autoexec.bat config.sys msdos.sys)
	if(! cp /n/c:/$i /n/c:/^`{echo $i | sed 's/\.(bat|sys)$/.p9/'}) {
		echo 'Could not back up '^$i^'; will not continue.'
		exit bad
	}

if(! test -d /n/c:/plan9 && ! mkdir /n/c:/plan9) {
	echo 'Could not create directory /n/c:/plan9.'
	exit bad
}

if(! cp /n/newfs/386/^(9load ld.com 9pcdisk) /tmp/plan9ini.bak /n/c:/plan9) {
	echo 'Could not copy Plan 9 boot files into /n/c:/plan9.'
	exit bad
}

chmod +w /n/c:/autoexec.bat /n/c:/config.sys /n/c:/msdos.sys

if(grep -si 'Plan ?9' /n/c:/config.sys || grep -si 'Plan ?9' /n/c:/autoexec.bat) {
	echo 'Plan 9 entries already in config.sys or autoexec.bat.'
	echo 'Not changing them; refer to Plan 9 install documentation'
	echo 'to configure manually.'
	exit bad
}

if(! grep -si '\[menu\]' /n/c:/config.sys) {
	{
		echo 1
		echo i
		echo '[menu]
'
		echo 'menuitem=windows, Windows
'
		echo 'menudefault=windows
'
		echo '
'
		echo '[common]
'
		echo '
'
		echo '[windows]
'
		echo .
		echo w
		echo q
	} | ed /n/c:/config.sys >/dev/null >[2]/dev/null
}

{
	echo 1
	echo '/\[[Mm][Ee][Nn][Uu]\]'
	echo '?^[Mm][Ee][Nn][Uu][Ii][Tt][Ee][Mm]='
	echo a
	echo 'menuitem=plan9, Plan 9 from Bell Labs
'
	echo .
	echo '$'
	echo a
	echo '
'
	echo '[plan9]
'
	echo '
'
	echo .
	echo w
	echo q
} | ed /n/c:/config.sys >/dev/null>[2]/dev/null

{
	echo 1
	echo i
	echo '@echo off
'
	echo 'if %config%==plan9 goto plan9
'
	echo 'goto notplan9
'
	echo ':plan9
'
	echo 'plan9\ld '^$dosdisk^'!dos!plan9/9load
'
	echo ':notplan9
'
	echo .
	echo w
	echo q
} | ed /n/c:/autoexec.bat >/dev/null>[2]/dev/null

fn zeroopt {
	if(grep -s '^'^$1^'=1' /n/c:/msdos.sys) {
		{
			echo '/^'^$1^'=1/s/=1/=0/'
			echo w
			echo q
		} | ed /n/c:/msdos.sys>/dev/null>[2]/dev/null
	}
	if not if (grep -s '^'^$1^'=0' /n/c:/msdos.sys)
		;
	if not {
		{
			echo 1
			echo i
			echo '[Options]
'
			echo 'Logo=0
'
			echo .
			echo w
			echo q
		} | ed /n/c:/msdos.sys>/dev/null>[2]/dev/null
	}
}

if(grep -si '^\[paths\]' /n/c:/msdos.sys){	# Windows 9x rather than DOS
	zeroopt Logo
#	zeroopt BootGUI
}
		
echo 'Plan 9 added to Windows 9X boot menu.'
exit ''