#!/bin/sh
# Build an OpenMandriva chroot (possibly including qemu setup)
# Usage:
# mkchroot [-v VERSION] [-a ARCH] Directory
# 	Default:
#		VERSION=cooker
#		ARCH=host arch

if [ "$(id -u)" != '0' ]; then
	exec sudo $0 "$@"
	exit 1
fi

usage() {
	cat <<EOF
$0 - Build an OpenMandriva chroot (possibly including qemu setup)
mkchroot [-v VERSION] [-a ARCH] Directory
 	Default:
		VERSION=cooker
		ARCH=host arch
EOF
	exit 1
}

OMV_VERSION=cooker
ARCH=$(uname -m)
[ "$ARCH" = "x86_64" ] && grep -q Ryzen /proc/cpuinfo && ARCH="znver1"
ROOTDIR=""
while [ "$#" -gt 0 ]; do
	case "$1" in
	-v|--version)
		shift
		OMV_VERSION="$1"
		;;
	-a|--arch)
		shift
		ARCH="$1"
		;;
	-h|--help)
		usage
		;;
	-*)
		usage
		;;
	*)
		if [ -z "$ROOTDIR" ]; then
			ROOTDIR="$1"
		else
			usage
		fi
		;;
	esac
	shift
done
[ -z "$ROOTDIR" ] && usage

TEMPDIR="$(mktemp -d /tmp/mkchrootXXXXXX)"
cd "$TEMPDIR"

# Poor man's version of "dnf install --installroot=" --
# need to get the repository configs from rpm packages
# without having the repositories configured...
PKGS=http://abf-downloads.openmandriva.org/$OMV_VERSION/repository/$ARCH/main/release/
curl -s -L $PKGS |grep '^<a' |cut -d'"' -f2 >PACKAGES
PRE_PACKAGES="distro-release-repos distro-release-repos-keys"
for i in $PRE_PACKAGES; do
	P=$(grep "^$i-[0-9].*" PACKAGES)
	if [ "$?" != "0" ]; then
		echo "Can't find $i package for target" >&2
		exit 1
	fi
	curl -O $PKGS/$P
	rpm -r "$ROOTDIR" -Uvh --ignorearch --nodeps $P
done

# Set up qemu if necessary
case "$ARCH" in
znver1)
	QEMUARCH=x86_64
	;;
i?86)
	QEMUARCH=i386
	;;
arm*)
	QEMUARCH=arm
	;;
*)
	QEMUARCH="$ARCH"
	;;
esac
case "$(uname -m)" in
znver1)
	HOSTARCH=x86_64
	;;
i?86)
	HOSTARCH=i386
	;;
arm*)
	HOSTARCH=arm
	;;
*)
	HOSTARCH="$(uname -m)"
	;;
esac

CHROOT_COMMAND="chroot"
if [ "$HOSTARCH" = "$QEMUARCH" ]; then
	# No qemu needed...
	unset QEMUARCH
elif [ "$HOSTARCH" = "x86_64" ] && [ "$QEMUARCH" = "i386" ]; then
	# Also no need for qemu -- setarch and friends are enough
	unset QEMUARCH
	CHROOT_COMMAND="i386 chroot"
elif [ "$HOSTARCH" = "aarch64" ] && [ "$QEMUARCH" = "arm" ]; then
	# FIXME is there any way to tell a 64-bit-only CPU apart from
	# a regular aarch64 CPU that can handle 32bit code???
	# For now, let's assume we're on a regular CPU...
	unset QEMUARCH
	CHROOT_COMMAND="linux32 chroot"
fi

if [ -n "$QEMUARCH" ]; then
	dnf -y install qemu-$QEMUARCH-static || :
	mkdir -p $ROOTDIR/usr/bin
	cp /usr/bin/qemu-$QEMUARCH-static $ROOTDIR/usr/bin/
fi

# FIXME allow better package selection
PACKAGES="basesystem task-devel rpm-build dnf bash"
if ! dnf -y install --installroot=$ROOTDIR --releasever=$OMV_VERSION --forcearch=$ARCH --refresh $PACKAGES; then
	echo "Failed to install packages, probably there are dependency problems."
	rm -rf $ROOTDIR
	exit 1
fi
# This should be there already, but better safe than sorry
mkdir $ROOTDIR/home &>/dev/null || :
cp -f /etc/passwd /etc/shadow /etc/group $ROOTDIR/etc

for i in /dev /dev/shm /dev/pts /proc /sys /home; do
	echo "$i	$ROOTDIR$i	none	bind	0	0" >>/etc/fstab
	mount "$ROOTDIR$i"
done

echo "Done -- you can enter the chroot environment using"
echo "	$CHROOT_COMMAND $ROOTDIR"