# 
# 2003-03-18
# http://homex.subnet.at/~max/diskless/
# 
# Description:
# - ask for the client screen's resolution
#   and check for the file "lowres" (which results in an 'automatic' 800x600)
# - determine the client's IP address
# - creates /tmp-indivs/$MYIP/
# - copies /etc and /var to it, creates /tmp there
# - make sure a "swap" file exists in /tmp-indivs/$MYIP/
# - creates a 1MB ramdisk and mounts it as /mnt/ramdisk
#   thus hiding the server's standard /etc, /var, /tmp
# - creates symlink /mnt/ramdisk/my-indiv/ -> /tmp-indivs/$MYIP
#   thus having the symlinks /etc, /var and /tmp pointing to
#   valid directories again
# - initialize the swap-file and do some tricks to mount it
#   via NFS
# - use the corresponding XF86Config-4 and do a little clean-up
# - set the hostname to the last octet of $MYIP with the prefix "dls"
#   (results in hostnames "dls1" through "dls127")
# 
# This way, each client has its own /etc, /var and /tmp with
# read-write. Instead of wasting local RAM, we have these directories
# mounted via NFS, thus the consume server-disk-space (and once
# at boot time lot's of time copying everything over the network) 
# instead of precious local RAM.
# 
# This script is started by the link /etc/rcS.d/S11diskless and thus
# after(!!) S10checkroot.sh as "/" is mounted "rw" then.
# 
# This script needs Bash-2.05a or similar. It will not run with
# Debian Potato's Bash, as this script uses the new Bash's read command
# with "timeouts" and similar options.
# 

# default resolution:
# possible values: 1024x768, 800x600
RES=1024x768

/bin/echo
/bin/echo Diskless setup starts ...
/bin/echo

MYIP=`/sbin/ifconfig eth0 | grep inet | awk '{print $2}' | sed 's/^addr://g'`
echo my ip: $MYIP

VALIDANSWER=n
while [ $VALIDANSWER == "n" ]; do
read -r -t 10 -n 1 -p "Does this client support 1024x768? [y|n]  " XReply
if [ -z "${XReply}" ]; then 
	# no answer given, check if the file "lowres" exists (800x600),
	# else use default resolution
	if [ -f /tmp-indivs/$MYIP/lowres ]; then
		/bin/echo No answer chosen, file \"lowres\" exists, using 800x600.
		RES=800x600
	else
		/bin/echo No answer chosen, using $RES.
	fi
	VALIDANSWER=y
else
	if [ $XReply == "y" ] || [ $XReply == "Y" ]; then
		/bin/echo
		/bin/echo Using resolution 1024x768.
		/bin/rm -f /tmp-indivs/$MYIP/lowres
		RES=1024x768
		VALIDANSWER=y
	elif [ $XReply == "n" ] || [ $XReply == "N" ]; then
		/bin/echo
		/bin/echo Using resolution 800x600.
		/usr/bin/touch /tmp-indivs/$MYIP/lowres
		RES=800x600
		VALIDANSWER=y
	else 
		/bin/echo
		/bin/echo You gave an invalid answer, try again...
	fi
fi
done

/bin/echo Re-creating /tmp-indivs/$MYIP ...
if [ -f /tmp-indivs/$MYIP/swap ]; then
	/bin/echo swap-file exists, re-using it
	/bin/mv /tmp-indivs/$MYIP/swap /tmp-indivs/swap_$MYIP
else
	/bin/echo swap-file doesnt exist yet, need to copy it later
fi
if [ -f /tmp-indivs/$MYIP/lowres ]; then
	/bin/echo lowres-file exists, handling it
	/bin/mv /tmp-indivs/$MYIP/lowres /tmp-indivs/lowres_$MYIP
fi
/bin/rm -rf /tmp-indivs/$MYIP/
/bin/mkdir /tmp-indivs/$MYIP/
if [ -f /tmp-indivs/lowres_$MYIP ]; then
	/bin/mv /tmp-indivs/lowres_$MYIP /tmp-indivs/$MYIP/lowres
fi
if [ -f /tmp-indivs/swap_$MYIP ]; then
	/bin/mv /tmp-indivs/swap_$MYIP /tmp-indivs/$MYIP/swap
fi
/bin/echo Re-creating /tmp-indivs/$MYIP done.

/bin/echo Creating and populating tmp, etc, var and perhaps swap in /tmp-indivs/$MYIP/ ...
/bin/mkdir /tmp-indivs/$MYIP/tmp/
/bin/chmod 1777 /tmp-indivs/$MYIP/tmp/
/bin/cp -aL /etc /tmp-indivs/$MYIP/
/bin/cp -aL /var /tmp-indivs/$MYIP/
if [ ! -f /tmp-indivs/$MYIP/swap ]; then
	/bin/echo Copying swap-file
	cp -aL /swap-template /tmp-indivs/$MYIP/swap
else
	echo swap-file already exists
fi
/bin/echo tmp, etc, var, swap done.

/bin/echo Creating 1MB ramdisk /dev/ram0 ...
/bin/dd if=/dev/zero of=/dev/ram0 bs=1k count=1024
/bin/echo Creating 1MB ramdisk done.

/bin/echo Creating EXT2-filesystem on ramdisk /dev/ram0 ...
/sbin/mke2fs -q -i 1024 -m0 /dev/ram0 1024
/bin/echo Creating EXT2-filesystem done.

/bin/echo Mounting /dev/ram0 to /mnt/ramdisk ...
/bin/mount -n -t ext2 -o rw,suid,dev,exec,async,nocheck /dev/ram0 /mnt/ramdisk
/bin/echo Mounting ramdisk done.

/bin/echo Creating symlink /mnt/ramdisk/my-indiv/ -> /tmp-indivs/$MYIP/ ...
/bin/ln -ivs /tmp-indivs/$MYIP/ /mnt/ramdisk/my-indiv
/bin/echo Creating symlink done.

/bin/echo Initializing and activating swap-file ...
/sbin/mkswap /tmp-indivs/$MYIP/swap
/sbin/losetup /dev/loop0 /tmp-indivs/$MYIP/swap
/sbin/swapon /dev/loop0
/bin/echo Initializing swap-file done.

/bin/echo Correcting /etc/X11/X, make it a symlink again ...
# otherwise, X won't start up
/bin/rm -f /etc/X11/X
/bin/ln -ivs /usr/bin/X11/XFree86 /etc/X11/X
/bin/echo Correcting /etc/X11/X done.

/bin/echo Setting XF86Config-4 according to screen resolution ...
if [ $RES == "1024x768" ]; then
	/bin/cp -f /etc/X11/XF86Config-4_1024x768 /etc/X11/XF86Config-4
elif [ $RES == "800x600" ]; then
	/bin/cp -f /etc/X11/XF86Config-4_800x600 /etc/X11/XF86Config-4
else
	/bin/echo WARNING: RES has no valid value, using 1024x768
	/bin/cp -f /etc/X11/XF86Config-4_1024x768 /etc/X11/XF86Config-4
	/bin/sleep 5
fi
/bin/echo Setting XF86Config-4 done.

/bin/echo Setting the hostname ...
/bin/echo -n "dlc" > /etc/hostname
/bin/echo $MYIP | sed s/\\./' '/g | awk '{print $4}' >> /etc/hostname
/bin/echo Setting hostname `/bin/cat /etc/hostname` done.

/bin/echo
/bin/echo Diskless setup done.
/bin/echo