#!/bin/bash
set -e

# uswsusp.config -- configure script for uswsusp debian package
#
# Copyright 2006, 2007	Tim Dijkstra <tim@famdijkstra.org>
# Copyright 2012	Rodolfo García Peñas <kix@kix.es>
#  04-2012 Full rewrited
# Released under GPLv2
CONFIGNAME=uswsusp.conf
CONFIGFILE=/etc/$CONFIGNAME
SWAPOFFSET=/usr/sbin/swap-offset

# If we don't have /proc or /sys we can't work, this will probably
# be a chroot or so.
function check_filesystems
{
	mountpoint -q /sys || {
		echo "/sys not mounted. Can't create $CONFIGNAME" >> /dev/stderr;
		exit 0; }
	mountpoint -q /proc || {
		echo "/proc not mounted. Can't create $CONFIGNAME" >> /dev/stderr;
		exit 0; }
}

# This function returns the full path in /dev/disk/by-uuid
# for a given /dev device. If not found, returns the /dev device.
function dev_to_uuid
{
	local link
	local path
	local uuid

	if [ -d /dev/disk/by-uuid ]; then
		uuid=$tmpswap
		for path in /dev/disk/by-uuid/*; do
			link=$(readlink -f "$path")
			if [ "$link" = "$tmpswap" ]; then
				uuid=${path}
				break;
			fi
		done

		tmpswap=$uuid
	fi
}

function get_list_of_swaps
{
	SWAPLIST=
	SWAPFIRST=
	KOMMA=
	tmpswap=

	# Swap file support is from 2.6.20
	if dpkg --compare-versions `uname -r` lt 2.6.20; then
		NO_FILE=' && $2!="file"'
	fi

	# List of swaps, listed by size
	for tmpswap in `sort -nr -k 3 /proc/swaps | awk '$2!="Type" '"$NO_FILE"' {print $1}'`; do
		dev_to_uuid
		SWAPLIST=${SWAPLIST}${KOMMA}${tmpswap}

		if [ -z "$KOMMA" ]; then
			SWAPFIRST=${tmpswap}
			KOMMA=", "
		fi
	done
}

# This function checks snapshot support
function check_snapshot_support
{
	if [ ! -e /sys/class/misc/snapshot/dev ]; then
		db_input critical uswsusp/no_snapshot || true
		db_fset uswsusp/no_snapshot hit true
		db_go || true
		exit 0
	fi
}

# This function sets the max size of image
function set_image_size
{
	IMAGESIZE=`awk '$1 == "MemTotal:" {printf("%lu\n", $2*1024*0.46)}' /proc/meminfo 2> /dev/null`
	if [ -n "$IMAGESIZE" ]; then
		db_set uswsusp/image_size $IMAGESIZE
	fi
}

# Read the configuration file
function read_config_file
{
# Luckily the parser in s2disk is quite strict
	for i in $LOWQ $MEDQ $HIGHQ $NOTQ; do
		VAL=`sed -n 's/^[[:space:]]*'"${i//_/ }"'[[:space:]]*[=:][[:space:]]*\([^[:space:]]*\)/\1/ p' $CONFIGFILE`

		# For boolean values it only checks for [yY]
		db_metaget uswsusp/${i} type
		TYPE=$RET

		if [ "boolean" = "$TYPE" ]; then
			if [ "$VAL" = "y" -o "$VAL" = "Y" ];  then
				db_set uswsusp/${i} true
			else
				db_set uswsusp/${i} false
			fi
		else
			db_set uswsusp/${i} "$VAL"
		fi
	done
}

function get_partition_to_use
{
	if [ -z "$USERSWAP" ]; then
		# The user didn't set one: Set the first as default
		SWAPDEFAULT=$SWAPFIRST
	elif echo "$SWAPLIST" | grep -q -e '\(^\|, \)'$USERSWAP'\(,\|$\)'; then
		# Valid swap partition
		SWAPDEFAULT=$USERSWAP
	elif [ -n "$USEROFFSET" ] && [ -x $SWAPOFFSET ]; then
		# Offset was specified
		# If we don't have swap-offset, this probably means uswsusp
		# was removed before, leaving the config file. Now we don't
		# have a way to check the offset. Best is to ask if this is OK

		devid=`printf "%x%02x" $(stat -c "0x%t 0x%T" $USERSWAP 2> /dev/null)`

		while read name type rest; do
			[ "$type" == "file" ]  || continue;
			[ "$(stat -c '%D' $name)" == "$devid" ] || continue;
			[ "$USEROFFSET" == "$(swap-offset $name | cut -c17- )" ] || continue;

			SWAPDEFAULT=$name
			break
		done < /proc/swaps
	fi
}

# Some people want to use a swap partition that is only mounted
# during suspend. This means we can't find it in /proc/swaps, but
# it is a valid option non the less. To not remove their changes
# we add it to the SWAPLIST, but not after we confirmed this is
# what they want.
function get_partition_mounted_to_use
{
	# This can be:
	#   Offset is given, no sbin/swap-offset
	#   Offset is given, USERSWAP:USEROFFSET not in /proc/swaps
	#   No offset, USERSWAP not in /proc/swaps
	db_input critical uswsusp/continue_without_swap || true
	db_get uswsusp/continue_without_swap
	if [ "$RET" = "true" ]; then
		SWAPLIST=${SWAPLIST}${KOMMA}${USERSWAP} ;
		SWAPDEFAULT=${USERSWAP}
		db_fset uswsusp/continue_without_swap hit true
	fi
}

function setup_priority_questions
{
	for i in $LOWQ; do
		db_input low uswsusp/${i} || true
	done

	for i in $MEDQ; do
		db_input medium uswsusp/${i} || true
	done

	for i in $HIGHQ; do
		db_input high uswsusp/${i} || true
	done

	# Ask questions
	db_go || true
}

function set_encryption
{
	# First ask filename
	while [ 1 ] ; do
		db_input low uswsusp/RSA_key_file || true
		db_go || true
		db_get uswsusp/RSA_key_file || true
		KEYFILE=$RET

		if [ -n "$KEYFILE" ]; then
			break
		fi

		db_reset uswsusp/RSA_key_file
	done

	# Then ask if we should generate it, default to yes if they don't have one yet
	if [ -e "$KEYFILE" ]; then
		db_set uswsusp/create_RSA_key false
	else
		db_set uswsusp/create_RSA_key true
	fi

	db_input low uswsusp/create_RSA_key || true
	db_go || true

	# If they want it created, ask nr bits and passphrase (twice)
	db_get uswsusp/create_RSA_key
	if [ "$RET" = "true" ]; then
		while [ 1 ]; do
			db_input low uswsusp/RSA_key_bits || true
			db_go || true
			db_get uswsusp/RSA_key_bits

			if [ -z "$RET" ] || [ $RET -ge 1024 -a $RET -le 4096 ]; then
				break;
			fi

			db_reset uswsusp/RSA_key_bits
		done

		P1=A; P2=B;

		while [ "$P1" != "$P2" ]; do
			db_input critical uswsusp/RSA_passphrase || true
			db_input critical uswsusp/RSA_passphrase_v || true
			db_go || true

			db_get uswsusp/RSA_passphrase
			if [ -n "$RET" ]; then
				P1=$RET;
			fi

			db_get uswsusp/RSA_passphrase_v
			if [ -n "$RET" ]; then
				P2=$RET;
			fi
		done
	fi
}

# MAIN SCRIPT #
. /usr/share/debconf/confmodule

LOWQ="snapshot_device compute_checksum compress early_writeout image_size suspend_loglevel max_loglevel shutdown_method"
MEDQ="resume_device encrypt"
HIGHQ=""
NOTQ="RSA_key_file shutdown_method resume_offset"

# Check if filesystems /proc and /sys are mounted
check_filesystems

# Reset these flags
db_fset uswsusp/no_swap hit false
db_fset uswsusp/no_snapshot hit false
db_fset uswsusp/continue_without_swap hit false

# Try to detect snapshot support
check_snapshot_support

# Get the list of swap devices
get_list_of_swaps

# Set the maximum size for image
set_image_size

# If config file, read it
if [ -e "$CONFIGFILE" ]; then
	read_config_file
fi

# Check resume_device and resume_offset from the config file
db_get uswsusp/resume_device
# If the file is a device file, translate to uuid file
# Else we can get an error about file is not active.
# debconf error uswsusp/continue_without_swap
tmpswap=$RET
dev_to_uuid
USERSWAP=$tmpswap

db_get uswsusp/resume_offset
USEROFFSET=$RET

# Get the swap partition to use
get_partition_to_use

# Some people want to use a swap partition that is only mounted
# during suspend. This means we can't find it in /proc/swaps, but
# it is a valid option non the less. To not remove their changes
# we add it to the SWAPLIST, but not after we confirmed this is
# what they want.
if [ -z "$SWAPDEFAULT" ]; then
	get_partition_mounted_to_use
fi

# If we still do not have a SWAPLIST, something is wrong
if [ -z "$SWAPLIST" ]; then
	db_input critical uswsusp/no_swap || true
	db_fset uswsusp/no_swap hit true
	db_go || true
	exit 0
fi
db_subst uswsusp/resume_device list $SWAPLIST
db_set uswsusp/resume_device $SWAPDEFAULT

# If we're still here, reset the seen flags on error messages
# Maybe they had problems before, but not anymore...
db_fset uswsusp/no_swap seen false
db_fset uswsusp/no_snapshot seen false

# Stetup questions according to  priority
setup_priority_questions

# Only if they want encryption, ask the RSA question
db_get uswsusp/encrypt
if [ "$RET" = "false" ]; then
	db_set uswsusp/create_RSA_key false
elif [ "$RET" = "true" ]; then
	set_encryption
fi