livecd-rootfs/live-build/lb_chroot_layered

#!/bin/sh

## live-build(7) - System Build Scripts
## Copyright (C) 2006-2012 Daniel Baumann <daniel@debian.org>
##
## 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.

## This is a fork of lb_chroot for layered live system.
## We don't want leaking host configuratino in each layer, and so,
## we clean and setup the chroot each time.
## In addition, we create the squashfs for each layer, but top one (live)
## which still can be configured after lb chroot call.

set -e

# Including common functions
( . "${LIVE_BUILD}/scripts/build.sh" > /dev/null 2>&1 || true ) || . /usr/lib/live/build.sh

# Automatically populating config tree
if [ -x auto/config ] && [ ! -e .build/config ]
then
	Echo_message "Automatically populating config tree."
	lb config
fi

# Setting static variables
DESCRIPTION="$(Echo 'customize the Debian system')"
HELP=""
USAGE="${PROGRAM} [--force]"

Arguments "${@}"

# Reading configuration files
Read_conffiles config/all config/common config/bootstrap config/chroot config/binary config/source
Set_defaults

# Setup cleanup function
Setup_cleanup

. config/functions

lb_chroot_remove_packages() {
	# Remove packages from the chroot specific to this layer
	#
	# $1: Name of the pass*
	local pass=$1

	Expand_packagelist "$(basename config/package-lists/*.removal-list.chroot_${pass})" "config/package-lists" \
			>> chroot/root/packages.chroot.removal
	Chroot chroot "xargs --arg-file=/root/packages.chroot.removal apt-get ${APT_OPTIONS} autoremove --purge"
	rm -f chroot/root/packages.chroot.removal
}

# Create the snap list specific to this layer
lb_chroot_snap_lists() {
	local pass=$1
	local prevpass=$2

	# This assumes that the prefix is unique for a given project
	local snap_for_pass=$(ls config/package-lists/*.snaplist.chroot_${pass}.full 2>/dev/null || true)
	local snap_for_prevpass=$(ls config/package-lists/*.snaplist.chroot_${prevpass}.full 2>/dev/null || true)

	if [ -z "${snap_for_pass}" ]; then
		return
	fi

	if [ -z "${snap_for_prevpass}" ]; then
		cp ${snap_for_pass} ${snap_for_pass%.full}
		return
	fi

	# Generate a list of snaps added to a layer.
	diff -NU0 ${snap_for_prevpass} ${snap_for_pass}|grep -Ev '^(---|\+\+\+|@@)'|cut -c2- > ${snap_for_pass%.full}
}

lb_chroot_install_snaps() {
	# Prepare the snap environment and install snaps into a chroot
	#
	# $1: Name of the pass

	local snaplist_file=$(ls config/package-lists/*.snaplist.chroot_${1} 2>/dev/null || true)

	if [ -z "${snaplist_file}" ]; then
		return
	fi

	snap_prepare chroot

	while read snap; do
		snap_preseed chroot "${snap}"
	done < $snaplist_file
}

create_chroot_pass() {
	local pass=$1
	local prevpass=$2
	local lowerlayers=$3
	local passtype=$4  # "first"|"last"|"" empty string
	shift 4 # restore ${*}

	# We have already treated that pass
	if [ -d "chroot.${pass}/" ]; then
		return
	fi

	export PASS=${pass}

	if [ "${passtype}" != "first" ]; then
		mkdir chroot.${pass}
		mount_overlay ${lowerlayers} "chroot.${pass}/" chroot/
	fi

	# Configuring chroot
	lb chroot_cache restore ${*}
	lb chroot_devpts install ${*}
	lb chroot_proc install ${*}
	lb chroot_selinuxfs install ${*}
	lb chroot_sysfs install ${*}
	lb chroot_debianchroot install ${*}
	lb chroot_dpkg install ${*}
	lb chroot_tmpfs install ${*}
	lb chroot_sysv-rc install ${*}
	lb chroot_upstart install ${*}
	lb chroot_hosts install ${*}
	lb chroot_resolv install ${*}
	lb chroot_hostname install ${*}
	lb chroot_apt install ${*}
	lb chroot_archives chroot install ${*}

	# Customizing chroot
	lb chroot_linux-image ${*}
	lb chroot_preseed ${*}
	lb chroot_early_hooks ${*}

	lb chroot_package-lists ${pass} ${*}
	lb chroot_install-packages ${pass} ${*}
	lb_chroot_remove_packages ${pass} ${*}

	# Snap management
	lb_chroot_snap_lists ${pass} ${prevpass}
	lb_chroot_install_snaps ${pass} ${*}

	# Kernel should be in first layer
	if [ "${passtype}" = "first" ]; then
		Chroot chroot "dpkg -l linux-headers-3* linux-headers-4*" 2>/dev/null \
			| awk '/^i/ {print $2}' > chroot.headers
		for i in $(cat chroot.headers); do
			Chroot chroot "apt-mark auto $i"
		done
	fi

	Chroot chroot "apt-get --purge -y autoremove"

	# Add live packages to top layer
	if [ "${passtype}" = "last" ]; then
		lb chroot_live-packages ${*}
	fi

	lb chroot_includes ${*}
	lb chroot_hooks ${*}
	lb chroot_hacks ${*}
	lb chroot_interactive ${*}

	Chroot chroot "dpkg-query -W" > chroot.packages.${pass}

	# Deconfiguring chroot
	lb chroot_archives chroot remove ${*}
	lb chroot_apt remove ${*}
	lb chroot_hostname remove ${*}
	lb chroot_resolv remove ${*}
	lb chroot_hosts remove ${*}
	lb chroot_sysv-rc remove ${*}
	lb chroot_upstart remove ${*}
	lb chroot_tmpfs remove ${*}
	lb chroot_dpkg remove ${*}
	lb chroot_debianchroot remove ${*}
	lb chroot_sysfs remove ${*}
	lb chroot_selinuxfs remove ${*}
	lb chroot_proc remove ${*}
	lb chroot_devpts remove ${*}
	lb chroot_cache save ${*}

	if [ "${passtype}" = "first" ]; then
		mv chroot chroot.${pass}
		mkdir chroot
	else
		umount chroot
	fi

	# Handle direct sublayer of current one
	# Extract the name of the pass corresponding to the sublayer
	for subpass in $(ls config/package-lists/*list.chroot_${pass}_* 2>/dev/null | sed -e "s/.*list\.chroot_\(${pass}_[^_]\+\).*/\1/"); do
		lowerlayers_for_subpass="chroot.${pass}:${lowerlayers}"
		lowerlayers_for_subpass="${lowerlayers_for_subpass%:}"
		create_chroot_pass "${subpass}" "${pass}" "${lowerlayers_for_subpass}" "" ${*}
	done
}

PASSES="${PASSES:-install live}"
CURPASS=1
PREVPASS=""
LASTPASS=$(echo $PASSES|wc -w)
LOWER_LAYERS=""
for _PASS in $PASSES
do
	PASSTYPE=""
	if [ $CURPASS -eq 1 ]; then
		PASSTYPE="first"
	elif [ $CURPASS -eq $LASTPASS ]; then
		PASSTYPE="last"
	fi

	create_chroot_pass "$_PASS" "$PREVPASS" "$LOWER_LAYERS" "$PASSTYPE" ${*}
	
	LOWER_LAYERS="chroot.${_PASS}:$LOWER_LAYERS"
	LOWER_LAYERS="${LOWER_LAYERS%:}"
	PREVPASS=${_PASS}
	
	CURPASS=$(( CURPASS + 1 ))
done

# remount last pass on chroot for lb binary
mount_overlay "${LOWER_LAYERS}" "chroot.${_PASS}/" chroot/

# Remove unused chroot binary corresponding to bottom layer (once everything is unmount)
TEARDOWNPATH="config/teardown_chroot_layered"
cat > $TEARDOWNPATH << EOF
#!/bin/sh
set -e
umount chroot
rm -rf chroot/
EOF
chmod +x $TEARDOWNPATH