#!/bin/sh
set -v

# Based on
# https://wiki.alpinelinux.org/wiki/LVM_on_LUKS

# Prerequisites for this script
# setup-interfaces
# ifup eth0

# Ask for passwords
IFS= read -sp 'Encryption password:' ENCPWD
echo

# Set up repositories  
cat <<EOF >/etc/apk/repositories
http://dl-cdn.alpinelinux.org/alpine/v3.8/main
http://dl-cdn.alpinelinux.org/alpine/v3.8/community
EOF

# Install disk management tools  
apk --no-cache add lvm2 cryptsetup e2fsprogs syslinux

# Create disk partitions
cat <<EOF | fdisk /dev/sda
n
p
1

+100m
a
1
n
p
2


t
2
8e
w
EOF

# Set up partition encryption
echo -n "${ENCPWD}" | cryptsetup -q luksFormat /dev/sda2
echo -n "${ENCPWD}" | cryptsetup open --type luks /dev/sda2 system

# Set up LVM
pvcreate /dev/mapper/system
vgcreate vg0 /dev/mapper/system
lvcreate -l 100%FREE vg0 -n root

# Format
mkfs.ext4 -m0 /dev/sda1
mkfs.ext4 -m1 /dev/vg0/root

# Mount
mount -t ext4 /dev/vg0/root /mnt
mkdir /mnt/boot
mount -t ext4 /dev/sda1 /mnt/boot

# Install Alpine linux
setup-disk -m sys /mnt

# Update boot-time volume information
BOOT_UUID=$(blkid /dev/sda1 | cut -d' ' -f2 | tr -d '"')
cat <<EOF >/mnt/etc/fstab
/dev/vg0/root                               /       ext4    rw,noatime,data=ordered   0   1
${BOOT_UUID}   /boot   ext4    rw,noatime,data=ordered   0   2
/dev/vg0/swap                               swap    swap    defaults                  0   0
EOF
echo "system /dev/sda2 none luks" >/mnt/etc/crypttab

# Rebuild initfs
sed -i 's/lvm/lvm cryptsetup/' /mnt/etc/mkinitfs/mkinitfs.conf
mkinitfs -c /mnt/etc/mkinitfs/mkinitfs.conf -b /mnt $(ls /mnt/lib/modules)

# Update extlinux (ignore the errors)
sed -i 's/rootfstype=ext4/rootfstype=ext4 cryptroot=\/dev\/sda2 cryptdm=system/' /mnt/etc/update-extlinux.conf
chroot /mnt update-extlinux

# Set time zone
chroot /mnt setup-timezone -z Europe/Prague

# Install basic system
apk --no-cache add apache2-utils gettext
wget https://dl.dasm.cz/basic.tar -O - | tar xf - -C /mnt
chroot /mnt apk --no-cache add ca-certificates curl bridge e2fsprogs-extra gettext iptables kbd-misc libcap libressl libseccomp postfix python3 py3-bcrypt py3-cffi py3-cryptography py3-dnspython py3-jinja2 py3-requests py3-six py3-werkzeug nginx util-linux acme-sh@vm lxc@vm
for SERVICE in cgroups consolefont crond iptables networking nginx ntpd postfix swap urandom vmmgr; do
    ln -s /etc/init.d/${SERVICE} /mnt/etc/runlevels/boot
done
ADMINPWD=$(htpasswd -bnBC 10 "" "${ENCPWD}" | tr -d ':\n' | sed 's/$2y/$2b/') envsubst </mnt/srv/vm/config.default.json >/mnt/srv/vm/config.json

# Change root password
echo "root:$(head -c 18 /dev/urandom | base64)" | chroot /mnt chpasswd

# Cleanup
rm -rf /mnt/root
mkdir /mnt/root

# Install bootloader to MBR
dd bs=440 count=1 conv=notrunc if=/mnt/usr/share/syslinux/mbr.bin of=/dev/sda

# Unmount and shut down
umount /mnt/boot
umount /mnt
vgchange -a n
cryptsetup luksClose system
poweroff