#!/bin/bash -euE
# librechroot

# Copyright 2010 Nicolás Reynolds
# Copyright 2011 Joshua Haase
# Copyright 2012 Luke Shumaker
#
# This file is part of Parabola.
#
# Parabola is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# Parabola is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Parabola. If not, see <http://www.gnu.org/licenses/>.

. /etc/libretools.conf

# This file (librechroot) is GPLv3+, but I would like to use some code
# modified from devtools' "makechrootpkg", which is GPLv2.
. "$(dirname "$0")/librechroot.gpl2"
# This gives us the functions:
#  - sync

cleanup=(':');
cleanup() {
	for cmd in "${cleanup[@]}"; do
		$cmd
	done
}

cmd=${0##*/}
usage() {
	echo "Usage: $cmd [OPTIONS] "
	echo 'Interacts with a chroot.'
	echo ''
	echo "The default CHROOT is \`${CHROOT}'."
	echo ''
	echo 'Options:'
	echo ' Settings:'
	echo " -n <CHROOT>     Use this chroot instead of \`$CHROOT'"
	echo ' -l <COPY>       Use this as the chroot copy instead of basing it'
	echo '                 on the username'
	echo ' -N              Disable networking in the chroot'
	echo ''
	echo ' Modes: (the last mode given will be used)'
	echo ' -C              Clean /repo in the chroot'
	echo ' -c              Clean the packages installed in the chroot'
	echo ' -I <FILE>       Install the package FILE into the chroot'
	echo ' -i <PKG>        Install the package PKG from repos into the chroot'
	echo ' -m              Make sure the chroot exists; do nothing else'
	echo ' -r <CMD>        Run CMD in the chroot'
	echo " -s              Sync the copy with the 'root' copy"
	echo ' -u              Update the chroot'
	echo ' -h              Print this message'
}

main() {
	CHROOTCOPY=$LIBREUSER
	[[ $CHROOTCOPY != root ]] || CHROOTCOPY=copy

	local mode=enter
	local archroot_args=(-f)
	local ARG=''
	while getopts 'n:l:NCcI:i:mrsuh' arg; do
		case $arg in
			n) CHROOT=$OPTARG;;
			l) CHROOTCOPY=$OPTARG;;
			N) archroot_args+=(-N);;

			C) mode=clean_repo;;
			c) mode=clean_pacman;;
			I) mode=install_file; ARG=$OPTARG;;
			i) mode=install_pkg; ARG=$OPTARG;;
			m) mode=noop;;
			r) mode=run; ARG=$OPTARG;;
			s) mode=sync;;
			u) mode=update;;

			h) usage; exit 0;;
			*) usage; exit 1;;
		esac
	done
	shift $(($OPTIND - 1))
	if [[ $# > 0 ]]; then
		usage
		exit 1
	fi

	# not local
	rootdir="${CHROOTDIR}/${CHROOT}/root"
	copydir="${CHROOTDIR}/${CHROOT}/${CHROOTCOPY}"

	########################################################################

	if (( EUID )); then
		error "This script must be run as root."
		exit 1
	fi

	# Keep this lock as long as we are running
	# Note that '9' is the same FD number as in (mk)archroot
	lock_open_write 9 "$copydir" "Locking chroot copy '$CHROOTCOPY'"

	if [[ ! -d $rootdir ]]; then
		libremkchroot "$CHROOT"
	fi

	if [[ ! -d $copydir ]] && [[ $mode != sync ]]; then
		sync
	fi

	########################################################################

	trap cleanup EXIT
	case "$mode" in
		clean_repo)
			rm -rf "${copydir}/repo/*"
			bsdtar -czf "${copydir}/repo/repo.db.tar.gz" -T /dev/null
			ln -s "repo.db.tar.gz" "${copydir}/repo/repo.db"
			;;
		clean_pacman)
			cleanup+=("rm -f '$copydir/clean' '$copydir/chrootexec'")
			cp -a "$(which chcleanup)"  "${copydir}/clean"
			echo '#!/bin/bash'        > "${copydir}/chrootexec"
			echo 'mkdir /build'      >> "${copydir}/chrootexec"
			echo 'cd /build; /clean' >> "${copydir}/chrootexec"
			chmod 755 "${copydir}/chrootexec"
			archroot "${archroot_args[@]}" "${copydir}" -r /chrootexec
			;;
		install_file)
			cleanup+=("rm '$copydir/${ARG##*/}'")
			cp "$ARG" "$copydir/${ARG##*/}"
			archroot "${archroot_args[@]}" "${copydir}" -r "pacman -U /${ARG##*/} --noconfirm"
			;;
		install_pkg) archroot "${archroot_args[@]}" "${copydir}" -i $ARG ;;
		noop) :;;
		run)         archroot "${archroot_args[@]}" "${copydir}" -r "$ARG" ;;
		sync) sync;;
		update)      archroot "${archroot_args[@]}" "${copydir}" -u ;;
		enter)       archroot "${archroot_args[@]}" "${copydir}" -r bash ;;
	esac
}

main "$@"