#!/bin/sh

### BEGIN INIT INFO
# Provides:		live-boot
# Required-Start:	$syslog bootmisc
# Required-Stop:
# Should-Start:		$local_fs
# Should-Stop:		halt reboot
# X-Stop-After:		umountroot
# Default-Start:	S
# Default-Stop:		0 6
# Short-Description:	live-boot init script
# Description:		Resyncs snapshots, evantually caches files in order to
#			let remove the media.
### END INIT INFO

# Authors: Tollef Fog Heen <tfheen@canonical.com>
#	   Marco Amadori <marco.amadori@gmail.com>

PATH=/usr/sbin:/usr/bin:/sbin:/bin
NAME=live-boot
SCRIPTNAME=/etc/init.d/${NAME}
DO_SNAPSHOT=/sbin/live-snapshot
SNAPSHOT_CONF="/etc/live/boot.d/snapshot.conf"

# Exit if system was not booted by live-boot
grep -qs boot=live /proc/cmdline || exit 0

# Read snapshot configuration variables
[ -r ${SNAPSHOT_CONF} ] && . ${SNAPSHOT_CONF}

# Load the VERBOSE setting and other rcS variables
[ -f /etc/default/rcS ] && . /etc/default/rcS

# Define LSB log_* functions.
# Depend on lsb-base (>= 3.0-6) to ensure that this file is present.
. /lib/lsb/init-functions

# Try to cache everything we're likely to need after ejecting.  This
# is fragile and simple-minded, but our options are limited.
cache_path()
{
	path="${1}"

	if [ -d "${path}" ]
	then
		find "${path}" -type f | xargs cat > /dev/null 2>&1
	elif [ -f "${path}" ]
	then
		if file -L "${path}" | grep -q 'dynamically linked'
		then
			# ldd output can be of three forms:
			# 1. linux-vdso.so.1 =>  (0x00007fffe3fb4000)
			#    This is a virtual, kernel shared library and we want to skip it
			# 2. libc.so.6 => /lib/libc.so.6 (0x00007f5e9dc0c000)
			#    We want to cache the third word.
			# 3. /lib64/ld-linux-x86-64.so.2 (0x00007f5e9df8b000)
			#    We want to cache the first word.
			ldd "${path}" | while read line
			do
				if echo "$line" | grep -qs ' =>  '
				then
					continue
				elif echo "$line" | grep -qs ' => '
				then
					lib=$(echo "${line}" | awk '{ print $3 }')
				else
					lib=$(echo "${line}" | awk '{ print $1 }')
				fi
				cache_path "${lib}"
			done
		fi

		cat "${path}" >/dev/null 2>&1
	fi
}

get_boot_device()
{
	# search in /proc/mounts for the device that is mounted at /live/image
	while read DEVICE MOUNT REST
	do
		if [ "${MOUNT}" = "/live/image" ]
		then
			echo "${DEVICE}"
			exit 0
		fi
	done < /proc/mounts
}

device_is_USB_flash_drive()
{
	# remove leading "/dev/" and all trailing numbers from input
	DEVICE=$(expr substr ${1} 6 3)

	# check that device starts with "sd"
	[ "$(expr substr ${DEVICE} 1 2)" != "sd" ] && return 1

	# check that the device is an USB device
	if readlink /sys/block/${DEVICE} | grep -q usb
	then
		return 0
	fi

	return 1
}

do_stop ()
{
	if ! grep -qs nopersistent /proc/cmdline && grep -qs persistent /proc/cmdline
	then
		# ROOTSNAP and HOMESNAP are defined in ${SNAPSHOT_CONF} file
		if [ ! -z "${ROOTSNAP}" ]
		then
			${DO_SNAPSHOT} --resync-string="${ROOTSNAP}"
		fi

		if [ ! -z "${HOMESNAP}" ]
		then
			${DO_SNAPSHOT} --resync-string="${HOMESNAP}"
		fi
	fi

	# check for netboot
	if [ ! -z "${NETBOOT}" ] || grep -qs netboot /proc/cmdline || grep -qsi root=/dev/nfs /proc/cmdline  || grep -qsi root=/dev/cifs /proc/cmdline
	then
		return 0
	fi

	# check for toram
	if grep -qs toram /proc/cmdline
	then
		return 0
	fi

	# Don't prompt to eject the SD card on Babbage board, where we reuse it
	# as a quasi-boot-floppy. Technically this uses a bit of ubiquity
	# (archdetect), but since this is mostly only relevant for
	# installations, who cares ...
	if type archdetect >/dev/null 2>&1
	then
		subarch="$(archdetect)"

		case $subarch in
			arm*/imx51)
				return 0
				;;
		esac
	fi

	prompt=1
	if [ "${NOPROMPT}" = "Yes" ]
	then
		prompt=
	fi

	for path in $(which halt) $(which reboot) /etc/rc?.d /etc/default $(which stty) /bin/plymouth
	do
		cache_path "${path}"
	done

	for x in $(cat /proc/cmdline)
	do
		case ${x} in
			quickreboot)
				QUICKREBOOT="Yes"
				;;
		esac
	done

	mount -o remount,ro /live/cow

	if [ -z ${QUICKREBOOT} ]
	then

		# Exit if the system was booted from an ISO image rather than a physical CD
		grep -qs find_iso= /proc/cmdline && return 0
		# TODO: i18n
		BOOT_DEVICE="$(get_boot_device)"

		if device_is_USB_flash_drive ${BOOT_DEVICE}
		then
			# do NOT eject USB flash drives!
			# otherwise rebooting with most USB flash drives
			# failes because they actually remember the
			# "ejected" state even after reboot
			MESSAGE="Please remove the USB flash drive"

			if [ "${NOPROMPT}" = "usb" ]
			then
				prompt=
			fi

		else
			# ejecting is a very good idea here
			MESSAGE="Please remove the disc, close the tray (if any)"

			if [ -x /usr/bin/eject ]
			then
				eject -p -m /live/image >/dev/null 2>&1
			fi

			if [ "${NOPROMPT}" = "cd" ]
			then
				prompt=
			fi

		fi

		[ "$prompt" ] || return 0

		if [ -x /bin/plymouth ] && plymouth --ping
		then
			plymouth message --text="${MESSAGE} and press ENTER to continue:"
			plymouth watch-keystroke > /dev/null
		else
			stty sane < /dev/console

			printf "\n\n${MESSAGE} and press ENTER to continue:" > /dev/console

			read x < /dev/console
		fi
	fi
}

case "${1}" in
	start|restart|reload|force-reload|status)
		[ "${VERBOSE}" != no ] && log_end_msg 0
		;;

	stop)
		log_begin_msg "${NAME} is resyncing snapshots and caching reboot files..."
		do_stop

		case "${?}" in
			0|1)
				[ "${VERBOSE}" != no ] && log_end_msg 0
				;;

			2)
				[ "${VERBOSE}" != no ] && log_end_msg 1
				;;
		esac
		;;

	*)
		log_success_msg "Usage: ${SCRIPTNAME} {start|stop|restart|force-reload}" >&2
		exit 3
		;;
esac