ramdisk

# Ramdisk filesystem mounting			-*- shell-script -*-

ramroot_is_remote()
{
	case "$1" in
		http://*|https://*|ftp://*)
			true;;
		*)
			false;;
	esac
}

ramroot_is_xzipped()
{
	case "$1" in
		*.xz)
			true;;
		*)
			false;;
	esac
}

ramroot_mount()
{
	local ramroot="$1"
	local memtotal=$(awk '/^MemTotal:/{print $2"k"}' /proc/meminfo)

	# Mount a ramdisk to extract the tar image on
	if mount -t tmpfs -o size=${memtotal:-500M} tmpfs ${rootmnt} ; then
		:
	elif mount -t shm shm ${rootmnt} ; then
		:
	else
		mount -t ramfs ramfs ${rootmnt}
	fi

	# Download and extract ramdisk tar image
	if ramroot_is_remote "$ramroot"; then
		busybox wget -O - "$ramroot"
	else
		busybox cat "$ramroot"
	fi | if ramroot_is_xzipped "$ramroot"; then
		pixz -d -t
	else
		busybox cat
	fi | ( cd ${rootmnt} && busybox tar -x ) || panic 'Unable to extract root filesystem'
}

mountroot()
{
	[ "$quiet" != "y" ] && log_begin_msg "Running /scripts/ramdisk-top"
	run_scripts /scripts/ramdisk-top
	[ "$quiet" != "y" ] && log_end_msg

	# Parse command line options to get ramroot
	local ramroot
	for x in $(cat /proc/cmdline); do
		case "$x" in
		ramroot=*)
			ramroot="${x#ramroot=}"
			;;
		esac
	done
	if [ -z "$ramroot" ] && [ -e /ramroot.xz ]; then
		ramroot=/ramroot.xz
	fi
	if [ -z "$ramroot" ]; then
		panic "No tar image for root found. Try passing ramroot= bootarg."
	fi

	# Configure networking if necessary
	if ramroot_is_remote "$ramroot"; then
		[ "$quiet" != "y" ] && log_begin_msg "Configuring networking"
		modprobe af_packet
		wait_for_udev 10
		configure_networking
		[ "$quiet" != "y" ] && log_end_msg
	fi

	[ "$quiet" != "y" ] && log_begin_msg "Running /scripts/ramdisk-premount"
	run_scripts /scripts/ramdisk-premount
	[ "$quiet" != "y" ] && log_end_msg

	[ "$quiet" != "y" ] && log_begin_msg "Installing root filesystem"
	ramroot_mount "$ramroot"
	[ "$quiet" != "y" ] && log_end_msg

	[ "$quiet" != "y" ] && log_begin_msg "Running /scripts/ramdisk-bottom"
	run_scripts /scripts/ramdisk-bottom
	[ "$quiet" != "y" ] && log_end_msg
}