installer

#! /usr/bin/env bash

# __START_OF_LICENSE__
# 
# Copyright (c) 2017 Michael D. Adams
# All rights reserved.
# 
# This file is part of the Aristotle software.
# 
# This program 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,
# or (at your option) any later version.
# 
# This program 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 this program; see the file LICENSE.  If not,
# see <http://www.gnu.org/licenses/>.
# 
# __END_OF_LICENSE__

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

# Bubblewrap: https://github.com/projectatomic/bubblewrap
bwrap_version="v0.11.0"

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

cmd_dir=$(dirname "$0") || exit 1

panic()
{
	echo "ERROR: $@"
	exit 1
}

tree_copy()
{
	local source_dir="$1"
	local destination_dir="$2"
	(cd "$source_dir" && tar -cf - .) | \
	  (cd "$destination_dir" && tar -xf -)
}

tree_adjust_perms()
{
	if [ $# -ne 2 ]; then
		return 2
	fi
	local mode="$1"
	local dir="$2"
	if [ "$mode" = public ]; then
		#find "$dir" \( -type f -o -type d \) -exec chmod go=u,g-w,o-w {} \;
		find "$dir" \( -type f -o -type d \) -print0 | xargs -n 1 -0 chmod go=u,g-w,o-w
	else
		#find "$dir" \( -type f -o -type d \) -exec chmod g=,o= {} \;
		find "$dir" \( -type f -o -type d \) -print0 | xargs -n 1 -0 chmod g=,o=
	fi
}

test_user_namespaces()
{
	local max_user_namespaces
	if [ -f "/proc/sys/user/max_user_namespaces" ]; then
		max_user_namespaces=$(cat /proc/sys/user/max_user_namespaces) || \
		  return 1
	else
		max_user_namespaces=0
	fi
	if [ "$max_user_namespaces" -ne 0 ]; then
		echo 1
	else
		echo 0
	fi
}

usage()
{
	echo "$@"
	cat <<- EOF
	Usage
	=====

	$0 [options] -d \$install_dir

	Options
	=======

	-d \$install_dir
	    Set the install directory to \$install_dir.
	-a \$assignments_dir
	    Set the default assignment-definition directory to \$assignments_dir.
	-c
	    Remove old files first.
	-m \$sandbox_mode
	    Set the sandbox mode to \$sandbox_mode.
	-b \$sandbox_options
	    Set the extra sandbox options to \$sandbox_options.

	Examples
	========

	$0 -d ${SDE_TOP_DIR-${HOME}/public/sde}/packages/aristotle-current
	$0 -d ${SDE_TOP_DIR-${HOME}/public/sde}/packages/aristotle-current -c
	$0 -d ${SDE_TOP_DIR-${HOME}/public/sde}/packages/aristotle-current \\
	  -c -m bwrap -b "-A $HOME/public/sde"
	(avoid -c if symlink for assignments might be deleted)
	EOF
	exit 2
}

clean=0
install_dir=
assignments_dir=
sandbox_mode=
sandbox_option_spec=()

while getopts b:cd:a:m: opt; do
	case $opt in
	d)
		install_dir="$OPTARG";;
	a)
		assignments_dir="$OPTARG";;
	c)
		clean=1;;
	m)
		sandbox_mode="$OPTARG";;
	b)
		sandbox_option_spec="$OPTARG";;
	*)
		usage "invalid option";;
	esac
done
shift $((OPTIND - 1))

if [ -z "$install_dir" ]; then
	usage "no installation directory specified"
fi
abs_install_dir=$(readlink -f "$install_dir") || panic
packages_dir="$abs_install_dir/packages"
bin_dir="$abs_install_dir/bin"
bwrap_dir="$packages_dir/bwrap-$bwrap_version"
ari_config_file="$abs_install_dir/etc/config"

if [ -z "$sandbox_mode" ]; then
	has_user_namespaces=$(test_user_namespaces) || panic
	if [ "$has_user_namespaces" -ne 0 ]; then
		sandbox_mode=bwrap
	else
		sandbox_mode=unsafe
	fi
fi

sandbox_options=($(echo "$sandbox_option_spec")) || panic

umask 022

if [ "$clean" -ne 0 ]; then
	if [ -d "$install_dir" ]; then
		rm -rf "$install_dir" || panic
		if [ -d "$install_dir" ]; then
			panic "cannot remove directory $install_dir"
		fi
	fi
fi

for dir in bin etc packages; do
	target_dir="$install_dir/$dir"
	if [ ! -d "$target_dir" ]; then
		mkdir -p "$target_dir" || panic
	fi
done

cat > "$ari_config_file" <<- EOF
sandbox_mode $sandbox_mode
sandbox_options ${sandbox_options[@]}
EOF
[ $? -eq 0 ] || panic "cannot create configuration file"

"$cmd_dir/bin/ari_install_bwrap" -d "$bwrap_dir" -v "$bwrap_version" || panic

rm -f "$packages_dir/bwrap"
rm -f "$bin_dir/bwrap"
ln -s "bwrap-$bwrap_version" "$packages_dir/bwrap" || panic
ln -s "../packages/bwrap/bin/bwrap" "$bin_dir/bwrap" || panic

for dir in bin etc; do
	target_dir="$install_dir/$dir"
	if [ ! -d "$target_dir" ]; then
		panic
	fi
	tree_copy "$cmd_dir/$dir" "$target_dir" || panic
done

#target_file="$install_dir/etc/default_assignments"
#if [ ! \( -L "$target_file" -o -e "$target_file" \) ]; then
#	if [ -z "$assignments_dir" ]; then
#		assignments_dir="assignments"
#	fi
#	ln -s "$assignments_dir" "$target_file" || \
#	  panic "cannot make symlink $target_file"
#fi

tree_adjust_perms public "$install_dir" || \
  panic "cannot set permissions (permissions may be not correct)"