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 configuration 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

	# 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)
	parent_pass=$(get_parent_pass $pass)
	local snap_for_parent_pass=$(ls config/package-lists/*.snaplist.chroot_${parent_pass}.full 2>/dev/null || true)

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

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

	# Generate a list of snaps added to a layer.
	diff -NU0 ${snap_for_parent_pass} ${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
}

lb_chroot_includes () {
	# Copying includes from pass subdirectory
	local pass="$1"

	if [ ! -d config/includes.chroot.${pass} ]; then
		return
	fi

	cd config/includes.chroot.${pass}
	find . | cpio -dmpu --no-preserve-owner "${OLDPWD}"/chroot
	cd "${OLDPWD}"
}

reduce_pass_size () {
	# Remove duplicated files between parent and current pass
	# Note the empty directories created in a child pass are not removed
	local pass=$1
	local parent="$(get_parent_pass $pass)"

	$(is_root_layer $pass) && return

	pass_dir="overlay.${pass}"
	parent_pass_dir="overlay.${parent}"

	local list_pass=$(mktemp)
	local list_parent=$(mktemp)

	(cd $pass_dir && find . ! -type d  -printf "%h/%f|%s|%y|%U|%G|%m\n"|sort > $list_pass)
	(cd $parent_pass_dir && find . ! -type d  -printf "%h/%f|%s|%y|%U|%G|%m\n"|sort > $list_parent)

	# Only iterate on common files with same type, owner, permission and size
	comm -12 $list_pass $list_parent|cut -d'|' -f1|while read f; do
		# If file contents are different, keep it
		if ! diff --brief --no-dereference "$pass_dir/$f" "$parent_pass_dir/$f" >/dev/null; then
			continue
		fi
		# Files are strictly identical between the 2 passes (only mod or access times differs). No need for unused delta.
		Echo_message "reduce_pass_size: '$f' is strictly identical between $parent and $pass. Removing."
		rm "$pass_dir/$f"
	done

	rm $list_pass
	rm $list_parent
}

create_chroot_pass () {
	local pass=$1
	shift 1 # restore ${*}

	Echo_message "lb_chroot_layered: treating pass $pass"

	# We have already treated that pass just return.
	local overlay_dir="overlay.${pass}"
	if [ -d "$overlay_dir/" ]; then
		return
	fi

	# Only get some function executed on root passes
	# Copy bootstrap on root layers
	if $(is_root_layer $pass); then
		rm -f .build/chroot_linux-image .build/chroot_preseed .build/chroot_hacks
		cp -a chroot.bootstrap/ "$overlay_dir/"
	fi
	# Others have to be executed on every pass
	rm -f .build/chroot_early_hooks .build/chroot_hooks .build/chroot_interactive

	mkdir -p "$overlay_dir/"
	lowerdirs=$(get_lowerdirs_for_pass $pass)
	if [ -n "$lowerdirs" ]; then
		mkdir -p chroot/
		mount_overlay "$lowerdirs" "$overlay_dir" chroot/
	else
		ln -s "$overlay_dir/" chroot
	fi

	export PASS=${pass}
	setenv_file PASS "${pass}" config/environment.chroot

	# Configuring chroot
	lb chroot_devpts install ${*}
	lb chroot_proc install ${*}
	lb chroot_sysfs install ${*}

	# grub-probe should not be called as part of an image build so divert it
	divert_grub chroot

	# We run chroot_hacks only on root layers (update-initramfs diverted)
	if $(is_root_layer $pass); then
		divert_update_initramfs
	fi
	lb chroot_debianchroot install ${*}
	lb chroot_dpkg install ${*}
	lb chroot_tmpfs install ${*}
	lb chroot_hosts install ${*}
	lb chroot_resolv install ${*}
	lb chroot_hostname install ${*}
	lb chroot_apt install ${*}
	# Note: this triggers an upgrade + dist-ugprade; which may impact sublayers with more
	# diff content than desired. So only running this on root pass.
	# Only configure universe on root passes
	if $(is_root_layer $pass); then
		lb chroot_archives chroot install ${*}
		configure_universe
	fi

	# 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} ${*}
	lb_chroot_install_snaps ${pass} ${*}

	configure_network_manager

	# Mark kernel headers as autoremovable
	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

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

	# Add live packages to live layers
	for livepass in $LIVE_PASSES; do
		[ "$livepass" != "$pass" ] && continue
		lb chroot_live-packages ${*}
		break
	done

	# Run includes by pass
	lb_chroot_includes ${pass} ${*}

	lb chroot_hooks ${*}

	# Run chroot_hacks only on root layers.
	# chroot_hacks changes the mode of boot/initrd*. The side effect in
	# layered mode is to create an initrd on each layer with a significant
	# impact on image size (+30MB per layer). This is an issue even with
	# update-initramfs disabled.
	lb chroot_hacks ${*}

	lb chroot_interactive ${*}

	# Misc ubuntu cleanup and post-layer configuration
	clean_debian_chroot
	/usr/share/livecd-rootfs/minimize-manual chroot

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

	# Restore grub
	undivert_grub chroot

	# Deconfiguring chroot
	if $(is_root_layer $pass); then
		lb chroot_archives chroot remove ${*}
	fi
	lb chroot_apt remove ${*}
	lb chroot_hostname remove ${*}
	lb chroot_resolv remove ${*}
	lb chroot_hosts remove ${*}
	lb chroot_tmpfs remove ${*}
	lb chroot_dpkg remove ${*}
	lb chroot_debianchroot remove ${*}
	lb chroot_sysfs remove ${*}
	lb chroot_proc remove ${*}
	lb chroot_devpts remove ${*}

	if [ -n "$lowerdirs" ]; then
		umount chroot
		rmdir chroot
	else
		rm chroot
	fi

	reduce_pass_size $pass
}

if [ ! -d chroot.bootstrap/ ]; then
	mv chroot/ chroot.bootstrap/
fi
for _PASS in $PASSES
do
	create_chroot_pass "$_PASS" ${*}
done