#!/bin/sh

. /etc/init.d/modlibrc

usage()
{
	cat << EOF
Usage: rc.nfsroot [on|off|status|share [nfs_share]|noshare]
NFS root mount script - can only be called as an 'init' replacement.
Parameters:
  status  - check status of NFS root; returns 'running' if NFS mount on '/'
            is active, 'stopped' otherwise.
  on      - activate replacing 'init' by 'rc.nfsroot' -> boot with NFS root,
            but only if 'share' has also been set up. Adds something like
            'init=/etc/init.d/rc.nfsroot' to bootloader environment variable
            'kernel_args'.
  share   - persistently store NFS share name in bootloader environment for
            later use with 'mount'. This setting must be configured at least
            once before NFS root can be used. Adds variable 'nfsroot' to
            bootloader environment, setting its value. If called without
            parameter, this option prints the current 'nfsroot' values.
  noshare - remove NFS share name from bootloader environment. Even though it
            does no harm to have the NFS share around int the environment all
            the time, you may optionally remove it again using this option.
  off     - deactivate replacing 'init' by 'rc.nfsroot' -> boot without
            NFS root. Removes 'init' from bootloader environment variable
            'kernel_args'.
Examples:
  - rc.nfsroot on
  - rc.nfsroot share 192.168.178.22:/home/user/my-nfsroot
  - rc.nfsroot share
  - rc.nfsroot status
  - rc.nfsroot off
  - rc.nfsroot noshare
EOF
}

NFSROOT_ENV_VAR=nfs

start()
{
	[ -e /proc/mounts ] || mount proc
	if grep -q " / nfs " /proc/mounts; then
		echo "*** NFS root already mounted, done. ***"
		return
	fi

	# Remove leading and trailing spaces from nfsroot. Trailing invisible
	# garbage can be part of the value if the user defines the variable via
	# Putty directly at the Eva console prompt via copy & paste.
	nfsroot=$(sed -rn "s/^$NFSROOT_ENV_VAR[[:space:]]+([^[:space:]]+).*/\1/p" /proc/sys/urlader/environment)
	server="${nfsroot%:*}"

	if [ -z "$nfsroot" ]; then
		echo "*** No 'nfsroot' configured in bootloader environment, exiting. ***" >&2
		umount proc
		return
	fi

	echo "*** Switching to NFS root ... ***"

	# Prepare filesystem stuff neded by multid
	mount /var
	tar xf /var.tar -C /
	major=$(grep tffs /proc/devices)
	tffs_major=${major%%tffs}
	mkdir -p /var/flash
	mknod /var/flash/multid.leases	 c $tffs_major $((0x70))
	mknod /var/flash/ar7.cfg		 c $tffs_major $((0x71))
	# CONFIG_ETH_COUNT, HWRevision_ATA
	. /etc/init.d/rc.conf

	echo "*** Initialising network interfaces ... ***"
	# Start multid temporarily (not needed anymore after setup)
	multid -tiu || multid -ti
	sleep 2
	multid -s

	# Clean up filesystem stuff no longer neded by multid
	rm -f /var/flash/multid.leases
	rm -r /var/flash/ar7.cfg
	umount /var

	echo "*** Loading kernel modules nfs, lockd, sunrpc ... ***"
	if ! modprobe nfs; then
		echo "*** Could not load (all) kernel modules, exiting. ***" >&2
		lsmod >&2
		rmmod nfs; rmmod lockd; rmmod sunrpc; umount proc
		return
	fi

	echo "*** Looking for NFS server in network ... ***"
	local ping_count=5
	until [ $ping_count -eq 0 ] || ping -c 1 $server; do
		echo "ping retry countdown: $((ping_count--))"
	done
	if [ $ping_count -eq 0 ]; then
		echo "*** NFS server not found, exiting. ***" >&2
		rmmod nfs; rmmod lockd; rmmod sunrpc; umount proc
		return
	fi

	echo "*** Mounting NFS root ... ***"
	if ! mount -t nfs -o nolock $nfsroot /var; then
		echo "*** NFS mount failed, exiting. ***" >&2
		rmmod nfs; rmmod lockd; rmmod sunrpc; umount proc
		return
	fi

	echo "*** Pivoting to NFS root ... ***"
	umount proc
	cd /var
	[ -d oldroot ] || mkdir -p oldroot
	if pivot_root . oldroot; then
		echo "*** NFS root pivoting succeeded, done. ***"
	else
		echo "*** NFS root pivoting failed, exiting. ***" >&2
	fi
}

bootstatus()
{
	grep "kernel_args" /proc/sys/urlader/environment | grep -q "init\=/etc/init\.d/rc\.nfsroot" \
			&& echo 'enabled' \
			|| echo 'disabled'
}

if [ "$PPID" == "0" ]; then
	echo "*** $0 called as an init process, start setting up NFS root ... ***"
	start
	echo "*** Creating device /dev/console on NFS root ... ***"
	# Try to remove existing filesystem object before creating device node
	[ -e /dev/console ] && rm -f /dev/console 2>/dev/null
	# We need this to be able to redirect std{in,err,out}
	mknod /dev/console c 5 1
	echo "*** Switching to init ... ***"
	exec init >/dev/console 2>&1 <&1
fi

case $1 in
	start|stop)
		;;
	""|load)
		echo "nfsroot is $(bootstatus)"
		# no webinterface
		# modreg cgi 'nfsroot' 'NFS Root'
		modreg daemon --disable nfsroot
		;;
	bootstatus)
		bootstatus
		;;
	status)
		grep -q " / nfs " /proc/mounts \
			&& echo 'running' \
			|| echo 'stopped'
		;;
	on)
		. kernel_args
		newval=$(ka_getArgs | sed -r 's/(.*[^ ])?( *init=[^ ]*)(.*)/\1\3/ ; s/^ +(.*)/\1/')
		echo "kernel_args init=/etc/init.d/rc.nfsroot $newval" > /proc/sys/urlader/environment
		echo "NFS root switched on (reboot to apply)"
		;;
	off)
		. kernel_args
		newval=$(ka_getArgs | sed -r 's/(.*[^ ])?( *init=[^ ]*)(.*)/\1\3/ ; s/^ +(.*)/\1/')
		echo "kernel_args $newval" > /proc/sys/urlader/environment
		echo "NFS root switched off (reboot to apply)"
		;;
	share)
		if [ "$2" ]; then
			echo "$NFSROOT_ENV_VAR $2" > /proc/sys/urlader/environment
			echo "NFS share name added to bootloader environment"
		else
			nfs_share=$(sed -nr "s/^$NFSROOT_ENV_VAR[[:space:]]+(.*)/\1/p" /proc/sys/urlader/environment)
			[ -n "$nfs_share" ] \
				&& echo "$nfs_share" \
				|| echo "NFS share name is currently empty"
		fi
		;;
	noshare)
		echo "$NFSROOT_ENV_VAR" > /proc/sys/urlader/environment
		echo "NFS share name removed from bootloader environment"
		;;
	*)
		usage >&2
		exit 1
		;;
esac