live-tools 1:20171207 / bin / live-persistence

#!/bin/sh

# live-tools(7) - System Support Scripts
# Copyright (C) 2006-2015 Daniel Baumann <mail@daniel-baumann.ch>
#
# This program comes with ABSOLUTELY NO WARRANTY; for details see COPYING.
# This is free software, and you are welcome to redistribute it
# under certain conditions; see COPYING for details.

set -e

# We're gonna mess with stderr's file descriptor below, so we save a
# reference to it in fd 3 if we want to print to stderr
exec 3>&2

error ()
{
	echo "error: ${@}" >&3
	exit 1
}

# Exit if user is unprivileged
if [ "$(id -u)" -ne 0 ]
then
	echo "E: need root privileges" >&3

	exit 1
fi

# Exit if live-boot is not installed
if [ ! -e /lib/live/boot ]
then
	echo "E: live-boot not installed" >&3

	exit 1
fi

# import Cmdline_old()
. /lib/live/boot/9990-cmdline-old || error 'Could not source /lib/live/boot/9990-cmdline-old'

# Set variable names needed by get_custom_mounts() etc.,
# and now initialized by live-boot in a file that we certainly
# don't want to source.
persistence_list="persistence.conf"
custom_overlay_label="persistence"
export persistence_list custom_overlay_label

# This will import the following functions and variables used below:
#   activate_custom_mounts()
#   get_custom_mounts()
#   open_luks_device()
#   probe_for_gpt_name()
#   removable_dev()
#   removable_usb_dev()
#   storage_devices()
#   where_is_mounted()
. /lib/live/boot/9990-misc-helpers.sh || error 'Could not source /lib/live/boot/9990-misc-helpers.sh'

usage ()
{
	echo "Usage: live-persistence [OPTION]... list [LABEL]...
List (on stdout) all partitions with names among LABEL(s) that are compatible
with live-boot's overlay persistence, and that are adhering to live-boot's
persistence filters (e.g. persistence-media). If no LABEL is given the default
in live-boot is used ('${custom_overlay_label}').
   or: live-persistence [OPTION]... activate VOLUME...
Activates persistence on the given VOLUME(s) (specified via block device).
Successes and failures are written to stdout. There are no checks for whether
the given volumes adhere to live-boot's options.
   or: live-persistence [OPTION]... close VOLUME...
Deactivates persistence on the given VOLUME(s) (specified via block device).

Note: The 'activate' and 'stop' actions only support partition-backed volumes
(e.g. /dev/sda2), not file-backed persistent volumes.

Kernel command-line options are parsed just like in live-boot and have the same
effect (see live-boot(7) for more information).

Most options correspond to the persistence-* options of live-boot, and will
override the corresponding options parsed from the kernel command-line.

General options:
  -h, --help            display this help and exit
  -l, --log-file=FILE   log the execution trace to FILE

Options affecting the 'list' action:
  -e, --encryption=LIST override 'persistence-encryption'
  -m, --media=VALUE     override 'persistence-media'
  -g, --gpt-only        only list GPT partitions

Options affecting the 'activate' action:
  -r, --read-only       enable 'persistence-read-only'
  -w, --read-write      disable 'persistence-read-only'
  -u, --union=VALUE     override 'union'"
}

warning ()
{
	echo "warning: ${@}" >&3
}

dbus_udisks_get_attribute ()
{
	dev="${1}"
	attribute="${2}"
	re='^[[:space:]]*variant[[:space:]]\+string[[:space:]]\+"\(.*\)"$'

	dbus-send --system --print-reply --dest=org.freedesktop.UDisks \
		/org/freedesktop/UDisks/devices/$(basename ${dev}) \
		org.freedesktop.DBus.Properties.Get \
		string:org.freedesktop.UDisks.Device \
		string:"${attribute}" | \
		grep -e "${re}" | sed "s|${re}|\1|"
}

# We override the following two functions from live-helpers since old
# blkid (i.e. util-linux and libblkid1) doesn't support GPT. We use dbus
# instead (which should be available in user-space).
get_gpt_name ()
{
	dev="${1}"

	dbus_udisks_get_attribute ${dev} partition-label
}

is_gpt_device ()
{
	dev="${1}"

	[ "$(dbus_udisks_get_attribute ${dev} partition-scheme)" = "gpt" ]
}

# We override live-boot's logging facilities to get more useful error messages
log_warning_msg ()
{
	warning ${@}
}

# We override live-boot's panic() since it does a lot of crazy stuff
panic ()
{
	error ${@}
}

# Fix persistent ~/.gconf sub-dirs; activate_custom_mounts() creates
# empty dirs up to its mountpoint, but the file %gconf.xml has to be
# present in each of ~/.gconf's subdirs to make them valid. Hence we
# have a problem with a persistent ~/.gconf/X/Y if ~/.gconf/X was
# created by activate_custom_mounts() since it would lack its
# %gconf.xml file, making ~/.gconf/X/Y invalid. This functions makes
# sure that all subdirs of ~/.gconf contain %gconf.xml.
fix_gconf_dirs ()
{
	for home in /home/*
	do
		if [ ! -e "${home}/.gconf" ]
		then
			continue
		fi

		ownership=$(stat -c "%u:%g" "${home}")

		find "${home}/.gconf" -type d | while IFS="" read -r dir
		do
			conf="${dir}/%gconf.xml"

			if [ ! -e "${conf}" ]
			then
				touch "${conf}"
				chown ${ownership} "${conf}"
			fi
		done
	done
}

list_volumes ()
{
	labels=${@}
	whitelistdev=""

	case "${PERSISTENCE_MEDIA}" in
		removable)
			whitelistdev="$(removable_dev)"

			[ -z "${whitelistdev}" ] && return
			;;
		removable-usb)
			whitelistdev="$(removable_usb_dev)"

			[ -z "${whitelistdev}" ] && return
			;;
		*)
			whitelistdev=""
			;;
	esac

	volumes=$(find_persistence_media "${labels}" "${whitelistdev}")

	for vol in $volumes
	do
		# drop the "$label=" prefix
		vol=${vol#*=}

		if [ -n "${GPT_PARTITIONS_ONLY}" ] && ! is_gpt_device ${vol}
		then
			continue
		fi

		echo $vol
	done

	exit 0
}

activate_volumes ()
{
	volumes=${@}
	ret=0
	open_volumes=""
	successes=""
	failures=""

	# required by open_luks_device()
	exec 6>&1

	for vol in ${volumes}
	do
		if [ ! -b "${vol}" ]
		then
			warning "${vol} is not a block device"

			failures="${failures} ${vol}"
			ret=1

			continue
		fi

		luks_vol=""

		if /sbin/cryptsetup isLuks ${vol} >/dev/null
		then
			if luks_vol=$(open_luks_device "${vol}")
			then
				open_volumes="${open_volumes} ${luks_vol}"
			else
				failures="${failures} ${vol}"
			fi
		else
			open_volumes="${open_volumes} ${vol}"
		fi
	done

	custom_mounts="$(mktemp /tmp/custom_mounts-XXXXXX.list)"

	get_custom_mounts ${custom_mounts} ${open_volumes}

	if [ -s "${custom_mounts}" ]
	then
		activate_custom_mounts ${custom_mounts} >/dev/null
		fix_gconf_dirs
	fi

	rm -f ${custom_mounts}

	for vol in ${open_volumes}
	do
		if grep -qe "^${vol}\>" /proc/mounts
		then
			successes="${successes} ${vol}"
		else
			failures="${failures} ${vol}"
			ret=1
		fi
	done

	if [ -n "${successes}" ]
	then
		echo "Successes:"

		for vol in ${successes}
		do
			echo "  - ${vol}"
		done
	fi

	if [ -n "${failures}" ]
	then
		echo "Failures:"

		for vol in ${failures}
		do
			echo "  - ${vol}"
		done
	fi

	exit ${ret}
}

is_mounted_readonly ()
{
	grep -q "${1} [^ ]* [^ ]* \([^ ]*,\)\?ro\(,[^ ]*\)\?" /proc/mounts
}

get_readonly_link_dir ()
{
	# XXX: Probably only supports UNIONTYPE=aufs
	mount | grep ":${1}=" | cut -d' ' -f3
}

close_volumes ()
{
	volumes=${@}
	custom_mounts="$(mktemp /tmp/custom_mounts-XXXXXX.list)"

	get_custom_mounts ${custom_mounts} ${volumes}

	while read device source dest options # < ${custom_mounts}
	do
		if is_in_comma_sep_list link ${options}
		then
			# 'link' type persistence isn't mounted on
			# $dest but in read-only mode it has a special
			# mount we need to take care of. However, in
			# both cases we just leave all created links
			# in a broken state.
			# We can't just check PERSISTENCE_READONLY
			# since that's something one can change with
			# the activate action, so we check if $device
			# is mounted read-only instead.
			if is_mounted_readonly ${device}
			then
				umount "$(get_readonly_link_dir "${source}")"
			fi
		else
			umount ${dest}
		fi
	done < ${custom_mounts}

	rm -f ${custom_mounts}

	for vol in ${volumes}
	do
		backing=$(where_is_mounted ${vol})

		umount ${backing}
	done
}

Main ()
{
	# tracing get's activated by Cmdline_old() if "debug" is in
	# /proc/cmdline which will flood stderr, which we don't want
	exec 2>"/dev/null"

	# parse the kernel cmdline for live-boot's configuration as defaults
	Cmdline_old

	# disable tracing if enabled by Cmdline_old()
	set +x
	exec 2>&3

	PERSISTENCE="true"
	NOPERSISTENCE=""
	export PERSISTENCE NOPERSISTENCE

	# FIXME: we don't yet support file-backed custom persistence
	PERSISTENCE_STORAGE="filesystem"
	export PERSISTENCE_STORAGE

	# Should be set empty since live-boot already changed root for us
	rootmnt=""
	export rootmnt

	SHORTOPTS="e:,g,h,l:,m:,r,w,u:"
	LONGOPTS="encryption:,gpt-only,help,log-file:,media:,read-only,read-write,union:"
	OPTS=$(getopt -o ${SHORTOPTS} --longoptions ${LONGOPTS} -n "live-persistence" -- "$@")

	if [ "$?" -ne 0 ]
	then
		echo "Try 'live-persistence --help' for more information."
		exit 1
	fi

	eval set -- "$OPTS"

	while [ $# -gt 0 ]
	do
		case $1 in
			-e|--encryption)
				shift
				export PERSISTENCE_ENCRYPTION="${1}"
				;;

			-g|--gpt-only)
				GPT_PARTITIONS_ONLY="true"
				;;

			-h|--help)
				usage
				exit 0
				;;

			-l|--log-file)
				shift
				DEBUG_LOG_FILE="${1}"
				;;

			-m|--media)
				shift
				export PERSISTENCE_MEDIA="${1}"
				;;

			-r|--read-only)
				export PERSISTENCE_READONLY="true"
				;;

			-w|--read-write)
				export PERSISTENCE_READONLY=""
				;;

			-u|--union)
				shift
				export UNIONTYPE="${1}"
				;;

			--)
				shift
				break
				;;

			*)
				error "unrecognized option: ${1}"
				;;
		esac
		shift
	done

	if [ -n "${DEBUG_LOG_FILE}" ]
	then
		exec 2>"${DEBUG_LOG_FILE}"
		set -x
	fi

	action="${1}"
	shift

	case "${action}" in
		list)
			labels=${@}

			if [ -z "${labels}" ]
			then
				# use default label in live-boot
				labels=${custom_overlay_label}
			fi

			list_volumes ${labels}
			;;

		activate|close)
			volumes=${@}

			if [ -z "${volumes}" ]
			then
				error "you must specify at least one volume"
			fi

			${action}_volumes "${volumes}"
			;;

		"")
			error "no action specified"
			;;

		*)
			error "unrecognized action: ${action}"
			;;
	esac
}

Main ${@}