#!/bin/bash
set -e

[[ -z $1 ]] && echo "usage: ${0##*/} <mount point>" && exit 1
target=$1

[[ ! -d $target/ ]] && echo $target/ does not exist && exit 1
[[ -z `mount | grep ${target%%/}` ]] && echo partition is not mounted into $target/ && exit 1

[[ ! -f slackstart.conf ]] && echo slackstart.conf missing && exit 1
echo -n sourcing slackstart.conf ...
. ./slackstart.conf && echo done

[[ -z $tz ]] && echo define tz && exit 1
[[ -z $vpartition ]] && echo define vpartition && exit 1
[[ -z $fs ]] && echo define fs && exit 1
[[ -z $serial ]] && echo define serial && exit 1
[[ -z $swap ]] && echo define swap && exit 1
[[ -z $boot ]] && echo define boot && exit 1

if [[ $fs = ext4 ]]; then
	addopts=""
elif [[ $fs = reiser4 ]]; then
	addopts=",txmod=wa,discard"
elif [[ $fs = btrfs ]]; then
	addopts=",compress=lzo"
elif [[ $fs = f2fs ]]; then
	addopts=",compress_algorithm=lz4,compress_chksum,atgc,gc_merge,lazytime"
else
	echo file-system $fs not supported
	exit 1
fi

echo -n fstab ...
cat > $target/etc/fstab <<EOF && echo done
$vpartition / $fs defaults,noatime,nodiratime$addopts 0 1
EOF
(( swap == 1 )) && cat >> $target/etc/fstab <<EOF
${vpartition//1/2} swap swap defaults 0 0
EOF
cat >> $target/etc/fstab <<EOF
devpts /dev/pts devpts gid=5,mode=620 0 0
proc /proc proc defaults 0 0
tmpfs /dev/shm tmpfs defaults 0 0
EOF

echo -n enabling login prompt on $serial ...
if [[ -f $target/etc/inittab.dist ]]; then
	echo already
else
	mv $target/etc/inittab $target/etc/inittab.dist
	sed -e '/^#/d;
		/^$/d;' $target/etc/inittab.dist > $target/etc/inittab
	echo "s1:12345:respawn:/sbin/agetty --noclear --local-line $serial 115200 linux" >> $target/etc/inittab
	echo $serial >> $target/etc/securetty && echo done
fi
		#/ctrlaltdel/d;
		#/^c[[:digit:]]:/d;

echo -n setting up timezone for $tz ...
rm -f $target/etc/localtime-copied-from $target/etc/localtime
ln -s ../usr/share/zoneinfo/$tz $target/etc/localtime && echo done

#echo -n disabling setterm ...
#chmod -x $target/etc/rc.d/rc.setterm && echo done

if [[ $boot = lilo ]]; then

	rm -f $target/etc/lilo.conf

	echo -n checking whether the disk is unknown ...
	disk_major=`grep vda$ /proc/partitions | awk '{print $1}'`
	(( disk_major == 253 || disk_major == 252 )) && echo disk = /dev/vda bios=0x80 max-partitions=7 >> $target/etc/lilo.conf && echo yes/fixed || echo no

	echo -n setting up LILO ...
	cat >> $target/etc/lilo.conf <<EOF && echo done
lba32
serial = 0,115200n8
prompt
timeout = 50
compact
boot = /dev/vda
root = /dev/vda1
read-only
image = /boot/vmlinuz
	label = Linux
	append = "ro console=tty1 console=$serial,115200n8 mitigations=off"
EOF

	echo running LILO within chroot
	mount -o bind /dev $target/dev
	mount -o bind /proc $target/proc
	chroot $target lilo

elif [[ $boot = syslinux ]]; then

	# debian
	if [[ -f /usr/lib/syslinux/modules/bios/libcom32.c32 ]]; then
		mbrbin=/usr/lib/syslinux/mbr/mbr.bin
		mboot=/usr/lib/syslinux/modules/bios/mboot.c32
		libcom32=/usr/lib/syslinux/modules/bios/libcom32.c32
		echo found syslinux on debian/ubuntu
	# slackware with syslinux 6.04
	# https://github.com/pbraun9/slackbuilds/tree/master/previews/syslinux-next
	elif [[ -f /usr/share/syslinux/libcom32.c32 ]]; then
		mbrbin=/usr/share/syslinux/mbr.bin
		mboot=/usr/share/syslinux/mboot.c32
		libcom32=/usr/share/syslinux/libcom32.c32
		echo found modern syslinux on slackware
	else
		echo cannot find libcom32.c32 - install modern syslinux first
		exit 1
	fi

	devicep1=`mount | grep "/$target type" | awk '{print $1}'`
	[[ -z $devicep1 ]] && echo could not define devicep1 && exit 1

	echo boot partition is $devicep1 - all good?
	read -r

	# todo - tested with nbd0p1 only, check sda1 ==> sda
	device=`echo $devicep1 | sed -r 's/p?1$//'`
	echo boot device is $device - all good?
	read -r

	dd if=$mbrbin of=$device

        mkdir -p $target/boot/syslinux/

        extlinux --install $target/boot/syslinux --device $devicep1
	unset devicep1

        cp -fv $mboot $target/boot/syslinux/
        cp -fv $libcom32 $target/boot/syslinux/

	unset mbrbin mboot libcom32

	echo -n writing $target/boot/syslinux/syslinux.cfg ...
        cat > $target/boot/syslinux/syslinux.cfg <<EOF && echo done
serial 0 115200
console 1
nohalt 1

default linux
prompt 1
timeout 50

label linux
	linux /boot/vmlinuz
	append root=/dev/vda1 ro console=tty1 console=$serial,115200n8 mitigations=off
EOF

else

	echo boot is $boot - unknown boot setting

fi

# otherwise slackpkg gets stuck at signature verification of the checksum
echo -n update ssl trust anchors
chroot $target bash -ic "update-ca-certificates --fresh"

echo all done