lego -- build system management with schroot
Joe Balough 2012

lego is a utility for managing btrfs-snapshot chroots using the schroot tool.
To use lego, create a new Logical Volume, format it btrfs, and mount it under /builds.
Under /builds, create two subdirectories, /builds/bases and /builds/chroots.
Create a new btrfs subvolume under /builds/bases and set up that directory as a build chroot:
  Use debbootstrap to install a base operating system
  Copy some default .basrhrc, etc. files to etc/skel in the base-chroot
  Copy the sources list from the main system into the base-chroot for more repositories
  Chroot into the base-chroot and install at least the following software:
	build-essential subversion git vim diffstat texi2html texinfo cvs gawk chrpath wget screen \
	python python-apport python-apt python-apt-common python-argparse python-central python-crypto \
	python-gnupginterface python-httplib2 python-keyring python-launchpadlib python-lazr.restfulclient \
	python-lazr.uri python-minimal python-oauth python-pkg-resources python-ply python-problem-report \
	python-progressbar python-simplejson python-software-properties python-support python-wadllib \
	python-wsgi-intercept python-zope.interface sqlite3 autoconf libtool
  Change the /bin/sh symlink so that it points to /bin/bash
  Set up openembedded under /opt
Add the base-chroot to the schroot configuration file at /etc/schroot/schroot.conf
	[beableboard]
	type=btrfs-snapshot
	description=BeagleBoard System Build
	users=builder
	root-users=builder
	source-root-users=root
	btrfs-source-subvolume=/builds/bases/bb-base
	btrfs-snapshot-directory=/builds/chroots
Comment out home mount in /etc/schroot/default/fstab, otherwise the base server home directory is mounted there.
Add tmpfs mount point for /dev/shm (Required for python multithreading support):
  /etc/schroot/default/fstab add to end of list:
  tmpfs           /dev/shm        tmpfs   defaults,noexec,nosuid  0       0
  and remove /builds/bases/bb-base/dev/shm
  then # mkdir /builds/bases/bb-base/dev/shm
Create a script to ensure the user has a home directory inside the new chroot
  /etc/schroot/setup.d/60home
	set -e

	. "$SETUP_DATA_DIR/common-data"
	. "$SETUP_DATA_DIR/common-functions"
	. "$SETUP_DATA_DIR/common-config"

	# Plain chroots should not be able to use scripts, but check anyway to
	# be safe.
	if [ $CHROOT_TYPE = "plain" ]; then
		fatal "plain chroots may not run setup scripts; use directory instead"
	fi

	# Set up home directory for user if it does not already exist
	if [ ! -d "$CHROOT_MOUNT_LOCATION/$AUTH_HOME" ]; then
		HOMEDIR=$(/usr/bin/dirname "$CHROOT_MOUNT_LOCATION/$AUTH_HOME")
		if [ ! -d "$HOMEDIR" ]; then
			mkdir -p "$HOMEDIR"
		fi
		cp -rf "$CHROOT_MOUNT_LOCATION/etc/skel" "$HOMEDIR/$AUTH_USER"
		chown -R $AUTH_USER:$AUTH_USER "$HOMEDIR/$AUTH_USER"
		chown -R $AUTH_USER:$AUTH_USER "$CHROOT_MOUNT_LOCATION/opt/oebuild/sources"
	fi

Base system should now be set up.
Run lego --help for usage information.

Also included in this repository is a lego_completion script that will provide
bash completion for lego. Copy this script into /etc/bash_completion.d to enable it.