#!/bin/bash -ex
# usage:
# tar2fs chroot.tar image.raw [size_in_bytes [fstype]]

. shell-error
export LANG=C

if [ $# -lt 2 ]; then
	fatal "error: tar2fs needs at least two arguments"
fi

# this needs env_keep sudo setup to actually work
if [ -n "$GLOBAL_BUILDDIR" ]; then
	WORKDIR="$GLOBAL_BUILDDIR/vmroot"
else
	WORKDIR="$(mktemp --tmpdir -d vmroot-XXXXX)"
fi

[ -n "$WORKDIR" ] || fatal "couldn't come up with suitable WORKDIR"

[ -n "$GLOBAL_DEBUG" ] || message "WORKDIR: $WORKDIR"

MB=1048576		# a parted's "megabyte" in bytes is *broken*

SIZE_FACTOR=2		# multiply the sizes found by this value
BOOT_SIZE_FACTOR=2	# multiply /boot size by this value additionally
BOOTLOADERPARTSIZEM=0	# PReP partition size (ppc*)

CUR_BOUNDARY=0		# align first partition at 1MB for performance (+1)

BOOTFSTYPE=
BOOTPART=
EFIPARTFSTYPE=
EFIPART=

BOOTLOADER="$5"

ARCH="$(arch)"		# NB: sudo => no GLOBAL_ will do either; mind qemu-*

case "$ARCH" in
e2k)
	BOOTFSTYPE="ext2"       # firmware knows it
	BLOCKDEV="/dev/sda"     # ...hopefully...
	BOOTPART="1"
	ROOTPART="2"
	;;
ppc*)
	BOOTFSTYPE="ext4"
	BLOCKDEV="/dev/sda"
	BOOTLOADERPART="1"
	BOOTLOADERPARTSIZEM="8"
	ROOTPART="2"
	;;
*)
	if [ "$BOOTLOADER" == grub-efi ]; then
		EFIPART="1"
		EFIPARTSIZEM="256"
		EFIPARTFSTYPE="fat"
		ROOTPART="2"
	else
		ROOTPART="1"
	fi
	BLOCKDEV="/dev/sda"
	;;
esac

# figure out the part taken by /boot in the given tarball
boot_size() {
	if [ -n "$BOOTPART" ]; then
		tar tvf "$1" \
		| awk ' \
			BEGIN { sum=0 }
			/^-.* \.\/boot\// { sum=sum+$3 }
			END { print sum }'
	else
		echo "0"
	fi
}

# parted wrapper for convenience
parting() { parted "$LOOPDEV" --align optimal --script -- "$@"; }

# unfortunately parted is insane enough to lump alignment controls
# into unit controls so creating adjacent partitions sized in MiB
# is not as straightforward as it might be... thus "+1" padding;
# see also http://www.gnu.org/software/parted/manual/parted.html#unit
mkpart() {
	# a bit different start/end semantics to handle end of device too
	local start="$(($CUR_BOUNDARY + 1))"	# yes, we lose a megabyte
	if [ -n "$1" ]; then
		CUR_BOUNDARY="$(($start + $1))"
		local end="$CUR_BOUNDARY"MiB
	else
		local end="$OFFSET"MiB	# last sector of the image
	fi
	if [ -n "$2" ]; then
		CUR_FS="$2"
	else
		CUR_FS=ext2
	fi
	parting mkpart primary "$CUR_FS" "$start"MiB "$end"
}

# a tarball containing chroot with a kernel
TAR="$1"
[ -s "$TAR" ] || fatal "source tarball doesn't really exist"

# a path to the image to be generated
IMG="$2"
[ -d "$(dirname "$IMG")" ] || fatal "target directory doesn't exist"

# 0 means auto; if a value is specified it holds (no /boot subtracted)
ROOTSIZE="$3"
[ -n "$ROOTSIZE" -a "$ROOTSIZE" != 0 ] || unset ROOTSIZE

# image size in bytes
TARSIZE="$(stat -Lc %s "$TAR")"
# /boot size in that tarball
BOOTSIZE="$(boot_size "$TAR")"
DEFSIZE="$(($SIZE_FACTOR * ($TARSIZE - $BOOTSIZE)))"	# (exact sizes)
ROOTSIZE="$((${ROOTSIZE:-$DEFSIZE} + $MB - 1))"	# for ceil rounding to MB
# image and /boot sizes in megabytes
ROOTSIZEM="$(($ROOTSIZE / $MB))"
BOOTSIZEM="$((($SIZE_FACTOR * $BOOT_SIZE_FACTOR * $BOOTSIZE + $MB - 1) / $MB))"

# tested to work: ext[234], jfs
# NB: xfs doesn't have a spare sector for the bootloader
ROOTFSTYPE="${4:-ext4}"

# single root partition hardwired so far,
# add another image for home/data/swap if needed
ROOTDEV="$BLOCKDEV$ROOTPART"

# last preparations...
MKFS="mkfs.$ROOTFSTYPE ${BOOTFSTYPE:+mkfs.$BOOTFSTYPE} \
  ${EFIPARTFSTYPE:+mkfs.$EFIPARTFSTYPE}"
for i in losetup sfdisk parted kpartx $MKFS; do
	if ! type -t "$i" >&/dev/null; then
		fatal "$i required but not found in host system"
	fi
done

LOOPDEV="$(losetup --find)"	# would be sad about non-binary megabytes too
ROOTFS="$WORKDIR/chroot"

BOOTFS=
EFIPARTFS=
if [ -n "$BOOTPART" ]; then
	BOOTFS="$ROOTFS/boot"
fi
if [ -n "$EFIPART" ]; then
	EFIPARTFS="$ROOTFS/boot/efi"
fi

exit_handler() {
	rc=$?
	cd /
	if [ -n "$ROOTFS" ]; then
		umount ${EFIPARTFS:+"$EFIPARTFS"} ${BOOTFS:+"$BOOTFS"} \
		  "$ROOTFS"{/dev,/proc,/sys,}

		if [ -n "$LOOPDEV" ]; then
			kpartx -d -s "$LOOPDEV" || {
				sleep 10
				kpartx -d -s -v "$LOOPDEV"
			}
			losetup --detach "$LOOPDEV"
		fi
		rm -r -- "$ROOTFS"
		rmdir -- "$WORKDIR"
	fi
	exit $rc
}

# handle -e in shebang as well
trap exit_handler EXIT ERR

# prepare disk image and a filesystem inside it
rm -f -- "$IMG"
OFFSET="$(($CUR_BOUNDARY + $EFIPARTSIZEM + $BOOTLOADERPARTSIZEM + $BOOTSIZEM + $ROOTSIZEM - 1))"
dd if=/dev/zero of="$IMG" conv=notrunc bs=$MB count=1 seek="$OFFSET"
losetup "$LOOPDEV" "$IMG"

if [ "$BOOTLOADER" == grub-efi ]; then
	parting mklabel gpt
else
	parting mklabel msdos
fi

if [ -n "$BOOTLOADERPART" ] && [ -n "$BOOTLOADERPARTSIZEM" ]; then
	case "$ARCH" in
		ppc*)
			parting mkpart primary ext2 2048s ${BOOTLOADERPARTSIZEM}M
			CUR_BOUNDARY="$(($CUR_BOUNDARY + $BOOTLOADERPARTSIZEM))"
			parting set 1 prep on
			parting set 1 boot on
			;;
	esac
fi

if [ -n "$EFIPART" ]; then
	EFIDEV="$EFIDEV$EFIPART"
	parting mkpart fat32 2048s ${EFIPARTSIZEM}M
	CUR_BOUNDARY="$(($CUR_BOUNDARY + $EFIPARTSIZEM))"
	parting set 1 boot on
	parting set 1 esp on
fi

if [ -n "$BOOTPART" ]; then
	BOOTDEV="$BLOCKDEV$BOOTPART"
	mkpart "$BOOTSIZEM"
fi

# not ROOTSIZEM but "the rest"; somewhat non-trivial arithmetics lurk in parted
mkpart

kpartx -a -s "$LOOPDEV"
LOOPROOT="/dev/mapper/$(basename "$LOOPDEV")p$ROOTPART"

mkfs."$ROOTFSTYPE" "$LOOPROOT"

if [ -n "$BOOTPART" ]; then
	LOOPBOOT="/dev/mapper/$(basename "$LOOPDEV")p$BOOTPART"
	mkfs."$BOOTFSTYPE" "$LOOPBOOT"
fi

if [ -n "$BOOTLOADERPART" ] && [ -n "$BOOTLOADERPARTSIZEM" ]; then
	LOOPBOOTLOADER="/dev/mapper/$(basename "$LOOPDEV")p$BOOTLOADERPART"
fi

if [ -n "$EFIPART" ]; then
	LOOPEFI="/dev/mapper/$(basename "$LOOPDEV")p$EFIPART"
	mkfs.fat -F32 "$LOOPEFI"
fi

ROOTUUID="$(blkid -s UUID -o value -c /dev/null "$LOOPROOT")"
if [ -n "$ROOTUUID" ]; then
       ROOTDEV="UUID=$ROOTUUID"
else
       ROOTDEV="$LOOPROOT"
fi

if [ -n "$BOOTPART" ]; then
	BOOTUUID="$(blkid -s UUID -o value -c /dev/null "$LOOPBOOT")"
	if [ -n "$BOOTUUID" ]; then
		BOOTDEV="UUID=$BOOTUUID"
	fi
fi

if [ -n "$EFIPART" ]; then
	EFIUUID="$(blkid -s UUID -o value -c /dev/null "$LOOPEFI")"
	if [ -n "$EFIUUID" ]; then
		EFIDEV="UUID=$EFIUUID"
	fi
fi

# mount and populate it
mkdir -pm755 "$ROOTFS"
mount "$LOOPROOT" "$ROOTFS"

if [ -n "$BOOTPART" ]; then
	mkdir -pm700 "$BOOTFS"
	mount "$LOOPBOOT" "$BOOTFS"
fi

if [ -n "$EFIPART" ]; then
	mkdir -pm751 "$EFIPARTFS"
	mount "$LOOPEFI" "$EFIPARTFS"
fi

tar -C "$ROOTFS" --numeric-owner -xf "$TAR"
for i in /dev /proc /sys; do mount --bind "$i" "$ROOTFS$i"; done

# loop device so lilo could work...
if grep -qe "[[:space:]]/[[:space:]]" "$ROOTFS/etc/fstab"; then \
	sed -i "s/LABEL=ROOT/$ROOTDEV/" "$ROOTFS/etc/fstab"
else
	echo "$ROOTDEV / $ROOTFSTYPE relatime 1 1" >> "$ROOTFS/etc/fstab"
fi

# target device at once
if [ -n "$BOOTPART" ]; then
	echo "$BOOTDEV /boot $BOOTFSTYPE defaults 1 2" >> "$ROOTFS/etc/fstab"
fi
if [ -n "$EFIPART" ]; then
	echo "$EFIDEV /boot/efi vfat umask=0,quiet,showexec,iocharset=utf8,codepage=866 1 2" >> "$ROOTFS/etc/fstab"
fi

# Query ARCH in chroot and redefine arch-dependent variable
ARCH="$(chroot "$ROOTFS" rpm --eval '%_host_cpu')"

# NB: don't stick BOOTFS here, it has slightly different semantics
pushd $ROOTFS/boot

# 4.9.76-elbrus-def-alt1.11.1 -> def
get_label() { echo "${1# *}" | sed -r 's,.*elbrus-([0-9a-z]+)-.*$,\1,'; }

KVERSIONS=
KVERSIONS="$(chroot "$ROOTFS" rpm -qa 'kernel-image*' \
            --qf '%{installtime} %{version}-%{name}-%{release}\n' \
        | sort -n \
        | cut -f 2 -d ' ' \
        | sed 's/kernel-image-//')"
[ -n "$KVERSIONS" ] || fatal "unable to deduce kernel version"
rm -f .origver

# clean fstab
sed -i "/LABEL=ROOT/d" "$ROOTFS/etc/fstab"
# ...target device too
sed -i "s,$LOOPROOT,$ROOTDEV," "$ROOTFS/etc/fstab"

echo "** KVERSIONS=[$KVERSIONS]" >&2

if [ "`echo $KVERSIONS | wc -w`" = 1 ]; then # 2+ labels
	echo -e "default=`get_label $KVERSIONS`\n" >> boot.conf
fi

# FIXME: relies on particular (current) kernel package naming scheme
for v in $KVERSIONS; do
	l="`get_label "$v"`"
	cat >> boot.conf <<EOF
label=$l
	partition=0
	image=/image-$v
	initrd=/initrd-$v.img
	cmdline=console=ttyS0,115200 console=tty0 consoleblank=0 hardreset root=UUID=$ROOTUUID

EOF
done

echo "** start of boot.conf"
cat boot.conf
echo "** end of boot.conf"

popd

# Setup bootloader
case "$BOOTLOADER" in
uboot)
	EXTLINUX_CONF="$ROOTFS/boot/extlinux/extlinux.conf"
	sed -i "s/LABEL=ROOT/$ROOTDEV/g" "$EXTLINUX_CONF"
	;;
lilo)
	# configure and install bootloader
	REGEXP='^.*: ([0-9]+) cylinders, ([0-9]+) heads, ([0-9]+) sectors/track*$'
	set -- $(sfdisk -g "$LOOPDEV" | grep -E "$REGEXP" | sed -r "s@$REGEXP@\1 \2 \3@")

	LILO_COMMON="lba32
delay=1
vga=0
image=/boot/vmlinuz
  initrd=/boot/initrd.img
  append=\"root=$ROOTDEV rootdelay=3 console=tty1 console=ttyS0,115200n8\"
  label=linux"

	cat > "$ROOTFS"/etc/lilo-loop.conf <<-EOF
	boot=$LOOPDEV
	disk=$LOOPDEV
	  bios=0x80
	  cylinders=$1
	  heads=$2
	  sectors=$3
	  partition=$LOOPROOT
	  start=63
	$LILO_COMMON
	EOF

	chroot "$ROOTFS" lilo -C /etc/lilo-loop.conf

	cat > "$ROOTFS"/etc/lilo.conf <<-EOF
	boot=$BLOCKDEV
	$LILO_COMMON
	EOF
	;;
grub-efi)
	chroot "$ROOTFS" grub-mkconfig -o /boot/grub/grub.cfg
	case "$ARCH" in
		*86)
			chroot "$ROOTFS" grub-install --target=i386-efi --removable
			sed -i 's/initrd16/initrdefi/g' "$ROOTFS/boot/grub/grub.cfg"
			sed -i 's/linux16/linuxefi/g' "$ROOTFS/boot/grub/grub.cfg"
		;;
		x86_64)
			chroot "$ROOTFS" grub-install --target=i386-efi --removable
			chroot "$ROOTFS" grub-install --target=x86_64-efi --removable
			sed -i 's/initrd16/initrdefi/g' "$ROOTFS/boot/grub/grub.cfg"
			sed -i 's/linux16/linuxefi/g' "$ROOTFS/boot/grub/grub.cfg"
		;;
		aarch64)
			chroot "$ROOTFS" grub-install --target=arm64-efi --removable
		;;
		armh)
			chroot "$ROOTFS" grub-install --target=arm-efi --removable
		;;
	esac
	;;
grub)
	chroot "$ROOTFS" grub-mkconfig -o /boot/grub/grub.cfg
	case "$ARCH" in
		*86*)
			chroot "$ROOTFS" grub-install --target=i386-pc "$LOOPDEV"
			sed -i 's/initrdefi/initrd16/g' "$ROOTFS/boot/grub/grub.cfg"
			sed -i 's/linuxefi/linux16/g' "$ROOTFS/boot/grub/grub.cfg"
			;;
		ppc*)
			[ -z "$LOOPBOOTLOADER" ] ||
				chroot "$ROOTFS" grub-install --target=powerpc-ieee1275 \
				--no-nvram "$LOOPBOOTLOADER"
			;;
	esac
	;;
esac

if [ -n "$SUDO_USER" ]; then
	chown "$SUDO_USER:$(id -g "$SUDO_USER")" "$IMG" ||:
fi
# maybe qemu interpreter was copied to chroot;
# this is no longer necessary, remove
rm -rf "$ROOTFS"/.host ||: