#!/bin/bash -e

[[ -w / ]] || exec sudo "$0" "$@"
[[ $# -eq 0 ]] && set -- env HOME=/root /bin/bash -l
mounts="proc sys dev dev/pts"

chroot=${0%/*}
case ${chroot} in
	.) chroot=${PWD} ;;
esac
cd "${chroot}"

maybe_mount() {
	local src=$1 dst=${2:-$1}
	mkdir -p $d/$m
	grep -sq "${chroot}/${dst}" /proc/mounts || mount --bind "/${src}" "${chroot}/${dst}"
}
for m in ${mounts} ; do
	maybe_mount ${m}
done

get_type() {
	case $(file "$1") in
		*x86-64*)        echo x86_64;;
		*"Intel 80386"*) echo i386;;
	esac
}
bin_dst=$(get_type bin/bash)
bin_src=$(get_type /bin/bash)
if [[ ${bin_dst} == ${bin_src} ]] ; then
	setarch=
else
	setarch="setarch ${bin_dst}"
fi

if [[ ! -L etc/mtab ]] ; then
	rm -f etc/mtab
	ln -sf /proc/mounts etc/mtab
fi
etc="
	hosts
	locale.gen
	localtime
	resolv.conf
"
home="
	.inputrc
	.nanorc
"
for f in \
	$(printf 'etc/%s ' ${etc}) \
; do
	cp /${f} ${f}
done
for f in ${home} ; do
	cp ~/${f} root/${f}
done

unset LS_COLORS # format changes over time
exec \
	${setarch} \
	chroot "${chroot}" \
	"$@"