#!/bin/bash
set -e

# Uncomment to activate debug
# debug=true

if [ "$debug" = true ]; then
  exec > >(tee -a -i "${0%.*}.log") 2>&1
  set -x
fi

# Architecture
architecture=${architecture:-"armhf"}
# Generate a random machine name to be used.
machine=$(tr -cd 'A-Za-z0-9' < /dev/urandom | head -c16 ; echo)
# Custom hostname variable
hostname=${2:-kali}
# Custom image file name variable - MUST NOT include .img at the end.
imagename=${3:-kali-linux-$1-bananapi}
# Suite to use, valid options are:
# kali-rolling, kali-dev, kali-bleeding-edge, kali-dev-only, kali-experimental, kali-last-snapshot
suite=${suite:-"kali-rolling"}
# Free space rootfs in MiB
free_space="300"
# /boot partition in MiB
bootsize="128"
# Select compression, xz or none
compress="xz"
# Choose filesystem format to format ( ext3 or ext4 )
fstype="ext3"
# If you have your own preferred mirrors, set them here.
mirror=${4:-"http://http.kali.org/kali"}
# Gitlab url Kali repository
kaligit="https://gitlab.com/kalilinux"
# Github raw url
githubraw="https://raw.githubusercontent.com"

# Check EUID=0 you can run any binary as root.
if [[ $EUID -ne 0 ]]; then
  echo "This script must be run as root"
  exit 1
fi

# Pass version number
if [[ $# -eq 0 ]] ; then
  echo "Please pass version number, e.g. $0 2.0, and (if you want) a hostname, default is kali"
  exit 0
fi

# Check exist bsp directory.
if [ ! -e "bsp" ]; then
  echo "Error: missing bsp directory structure"
  echo "Please clone the full repository ${kaligit}/build-scripts/kali-arm"
  exit 255
fi

# Current directory
current_dir="$(pwd)"
# Base directory
basedir=${current_dir}/bananapi-"$1"
# Working directory
work_dir="${basedir}/kali-${architecture}"

# Check directory build
if [ -e "${basedir}" ]; then
  echo "${basedir} directory exists, will not continue"
  exit 1
elif [[ ${current_dir} =~ [[:space:]] ]]; then
  echo "The directory "\"${current_dir}"\" contains whitespace. Not supported."
  exit 1
else
  echo "The basedir thinks it is: ${basedir}"
  mkdir -p ${basedir}
fi

components="main,contrib,non-free"
arm="kali-linux-arm ntpdate"
base="apt-transport-https apt-utils bash-completion console-setup dialog dkms e2fsprogs ifupdown initramfs-tools inxi iw linux-image-armmp man-db mlocate netcat-traditional net-tools parted pciutils psmisc rfkill screen tmux u-boot-menu u-boot-sunxi unrar usbutils vim wget whiptail zerofree"
desktop="kali-desktop-xfce kali-root-login xserver-xorg-video-fbdev xfonts-terminus xinput"
tools="kali-linux-default"
services="apache2 atftpd"
extras="alsa-utils bc bison bluez bluez-firmware kali-linux-core libnss-systemd libssl-dev triggerhappy"

packages="${arm} ${base} ${services}"

# Automatic configuration to use an http proxy, such as apt-cacher-ng.
# You can turn off automatic settings by uncommenting apt_cacher=off.
# apt_cacher=off
# By default the proxy settings are local, but you can define an external proxy.
# proxy_url="http://external.intranet.local"
apt_cacher=${apt_cacher:-"$(lsof -i :3142|cut -d ' ' -f3 | uniq | sed '/^\s*$/d')"}
if [ -n "$proxy_url" ]; then
  export http_proxy=$proxy_url
elif [ "$apt_cacher" = "apt-cacher-ng" ] ; then
  if [ -z "$proxy_url" ]; then
    proxy_url=${proxy_url:-"http://127.0.0.1:3142/"}
    export http_proxy=$proxy_url
  fi
fi

# create the rootfs - not much to modify here, except maybe throw in some more packages if you want.
debootstrap --foreign --keyring=/usr/share/keyrings/kali-archive-keyring.gpg --include=kali-archive-keyring \
  --components=${components} --arch ${architecture} ${suite} ${work_dir} http://http.kali.org/kali

# systemd-nspawn enviroment
systemd-nspawn_exec(){
  qemu_bin=/usr/bin/qemu-arm-static
  LANG=C systemd-nspawn -q --bind-ro ${qemu_bin} -M ${machine} -D ${work_dir} "$@"
}

# debootstrap second stage
systemd-nspawn_exec /debootstrap/debootstrap --second-stage

cat << EOF > ${work_dir}/etc/apt/sources.list
deb ${mirror} ${suite} ${components//,/ }
#deb-src ${mirror} ${suite} ${components//,/ }
EOF

# Set hostname
echo "${hostname}" > ${work_dir}/etc/hostname

# So X doesn't complain, we add kali to hosts
cat << EOF > ${work_dir}/etc/hosts
127.0.0.1       ${hostname}    localhost
::1             localhost ip6-localhost ip6-loopback
fe00::0         ip6-localnet
ff00::0         ip6-mcastprefix
ff02::1         ip6-allnodes
ff02::2         ip6-allrouters
EOF

# Disable IPv6
cat << EOF > ${work_dir}/etc/modprobe.d/ipv6.conf
# Don't load ipv6 by default
alias net-pf-10 off
EOF

cat << EOF > ${work_dir}/etc/network/interfaces
auto lo
iface lo inet loopback

auto eth0
allow-hotplug eth0
iface eth0 inet dhcp
EOF

# DNS server
echo "nameserver 8.8.8.8" > ${work_dir}/etc/resolv.conf

# Copy directory bsp into build dir.
cp -rp bsp ${work_dir}

export MALLOC_CHECK_=0 # workaround for LP: #520465

# Enable the use of http proxy in third-stage in case it is enabled.
if [ -n "$proxy_url" ]; then
  echo "Acquire::http { Proxy \"$proxy_url\" };" > ${work_dir}/etc/apt/apt.conf.d/66proxy
fi

cat << EOF > ${work_dir}/third-stage
#!/bin/bash -e
export DEBIAN_FRONTEND=noninteractive
export RUNLEVEL=1
ln -sf /bin/true /usr/sbin/invoke-rc.d
echo -e "#!/bin/sh\nexit 101" > /usr/sbin/policy-rc.d
chmod 755 /usr/sbin/policy-rc.d

apt-get update

apt-get -y install git-core binutils ca-certificates locales console-common less nano git cmake

# Create kali user with kali password... but first, we need to manually make some groups because they don't yet exist...
# This mirrors what we have on a pre-installed VM, until the script works properly to allow end users to set up their own... user.
# However we leave off floppy, because who a) still uses them, and b) attaches them to an SBC!?
# And since a lot of these have serial devices of some sort, dialout is added as well.
# scanner, lpadmin and bluetooth have to be added manually because they don't
# yet exist in /etc/group at this point.
groupadd -r -g 118 bluetooth
groupadd -r -g 113 lpadmin
groupadd -r -g 122 scanner
groupadd -g 1000 kali

useradd -m -u 1000 -g 1000 -G sudo,audio,bluetooth,cdrom,dialout,dip,lpadmin,netdev,plugdev,scanner,video,kali -s /bin/bash kali
echo "kali:kali" | chpasswd

aptops="--allow-change-held-packages -o dpkg::options::=--force-confnew"

# Linux console/Keyboard configuration
echo 'console-common console-data/keymap/policy select Select keymap from full list' | debconf-set-selections
echo 'console-common console-data/keymap/full select en-latin1-nodeadkeys' | debconf-set-selections

# Copy all services
cp -p /bsp/services/all/*.service /etc/systemd/system/

# This looks weird, but we do it twice because every so often, there's a failure to download from the mirror
# So to workaround it, we attempt to install them twice.
apt-get install -y \$aptops ${packages} || apt-get --yes --fix-broken install
apt-get install -y \$aptops ${packages} || apt-get --yes --fix-broken install
apt-get install -y \$aptops ${desktop} ${extras} ${tools} || apt-get --yes --fix-broken install
apt-get install -y \$aptops ${desktop} ${extras} ${tools} || apt-get --yes --fix-broken install
apt-get install -y \$aptops  systemd-timesyncd || apt-get --yes --fix-broken install
apt-get dist-upgrade -y \$aptops
apt-get autoremove -y

# Regenerated the shared-mime-info database on the first boot
# since it fails to do so properly in a chroot.
systemctl enable smi-hack

# Generate SSH host keys on first run
systemctl enable regenerate_ssh_host_keys

# Enable ssh server
systemctl enable ssh

# Copy bashrc
cp  /etc/skel/.bashrc /root/.bashrc

cd /root
apt -o APT::Sandbox::User=root download ca-certificates 2>/dev/null

# We replace the u-boot menu defaults here so we can make sure the build system doesn't poison it.
# We use _EOF_ so that the third-stage script doesn't end prematurely.
cat << '_EOF_' > /etc/default/u-boot
U_BOOT_PARAMETERS="console=ttyS0,115200 console=tty1 root=/dev/mmcblk0p1 rootwait panic=10 rw rootfstype=$fstype net.ifnames=0"
_EOF_

# Try and make the console a bit nicer
# Set the terminus font for a bit nicer display.
sed -i -e 's/FONTFACE=.*/FONTFACE="Terminus"/' /etc/default/console-setup
sed -i -e 's/FONTSIZE=.*/FONTSIZE="6x12"/' /etc/default/console-setup

rm -f /usr/sbin/policy-rc.d
unlink /usr/sbin/invoke-rc.d
EOF

chmod +755 ${work_dir}/third-stage
systemd-nspawn_exec /third-stage

# Clean system
systemd-nspawn_exec << EOF
rm -f /0
rm -rf /bsp
fc-cache -frs
rm -rf /tmp/*
rm -rf /etc/*-
rm -rf /hs_err*
rm -rf /userland
rm -rf /opt/vc/src
rm -f /etc/ssh/ssh_host_*
rm -rf /var/lib/dpkg/*-old
rm -rf /var/lib/apt/lists/*
rm -rf /var/cache/apt/*.bin
rm -rf /var/cache/apt/archives/*
rm -rf /var/cache/debconf/*.data-old
history -c
EOF
#Clear all logs
for logs in `find $work_dir/var/log -type f`; do > $logs; done

# Disable the use of http proxy in case it is enabled.
if [ -n "$proxy_url" ]; then
  unset http_proxy
  rm -rf ${work_dir}/etc/apt/apt.conf.d/66proxy
fi

# Enable the serial console
echo "T1:12345:respawn:/sbin/agetty -L ttyS0 115200 vt100" >> ${work_dir}/etc/inittab
# Load the ethernet module since it doesn't load automatically at boot.
echo "sunxi_emac" >> ${work_dir}/etc/modules

# Mirror replacement
if [ ! -z "${@:5}" ]; then
  mirror=${@:5}
fi

# Define sources.list
cat << EOF > ${work_dir}/etc/apt/sources.list
deb ${mirror} ${suite} ${components//,/ }
#deb-src ${mirror} ${suite} ${components//,/ }
EOF

mkdir -p ${work_dir}/etc/X11/xorg.conf.d/
cp "${basedir}"/../bsp/xorg/20-fbdev.conf ${work_dir}/etc/X11/xorg.conf.d/

# Build system will insert it's root filesystem into the extlinux.conf file so
# we sed it out, this only affects build time, not upgrading the kernel on the
# device itself.
sed -i -e 's/append.*/append console=ttyS0,115200 console=tty1 root=\/dev\/mmcblk0p1 rootwait panic=10 rw rootfstype=$fstype net.ifnames=0/g' ${work_dir}/boot/extlinux/extlinux.conf

# Calculate the space to create the image.
root_size=$(du -s -B1 ${work_dir} --exclude=${work_dir}/boot | cut -f1)
root_extra=$((${root_size}/1024/1000*5*1024/5))
raw_size=$(($((${free_space}*1024))+${root_extra}+$((${bootsize}*1024))+4096))

# Create the disk and partition it
echo "Creating image file ${imagename}.img"
fallocate -l $(echo ${raw_size}Ki | numfmt --from=iec-i --to=si) ${current_dir}/${imagename}.img
parted -s ${current_dir}/${imagename}.img mklabel msdos
parted -s -a minimal ${current_dir}/${imagename}.img mkpart primary $fstype 1MiB 100%

# Set the partition variables
loopdevice=`losetup -f --show ${current_dir}/${imagename}.img`
device=`kpartx -va ${loopdevice} | sed 's/.*\(loop[0-9]\+\)p.*/\1/g' | head -1`
sleep 5
device="/dev/mapper/${device}"
rootp=${device}p1

if [[ $fstype == ext4 ]]; then
  features="-O ^64bit,^metadata_csum"
elif [[ $fstype == ext3 ]]; then
  features="-O ^64bit"
fi
mkfs $features -t $fstype -L ROOTFS ${rootp}

# Create the dirs for the partitions and mount them
mkdir -p ${basedir}/root
mount ${rootp} ${basedir}/root

# We do this down here to get rid of the build system's resolv.conf after running through the build.
cat << EOF > ${work_dir}/etc/resolv.conf
nameserver 8.8.8.8
EOF

# Create an fstab so that we don't mount / read-only.
UUID=$(blkid -s UUID -o value ${rootp})
echo "UUID=$UUID /               $fstype    errors=remount-ro 0       1" >> ${work_dir}/etc/fstab

echo "Rsyncing rootfs to image file"
rsync -HPavz -q ${work_dir}/ ${basedir}/root/

# Unmount partitions
sync
umount ${rootp}
kpartx -dv ${loopdevice}

dd if=${work_dir}/usr/lib/u-boot/Bananapi/u-boot-sunxi-with-spl.bin of=${loopdevice} bs=1024 seek=8

cd "${basedir}"

losetup -d ${loopdevice}

# Limite use cpu function
limit_cpu (){
  rand=$(tr -cd 'A-Za-z0-9' < /dev/urandom | head -c4 ; echo) # Randowm name group
  cgcreate -g cpu:/cpulimit-${rand} # Name of group cpulimit
  cgset -r cpu.shares=800 cpulimit-${rand} # Max 1024
  cgset -r cpu.cfs_quota_us=80000 cpulimit-${rand} # Max 100000
  # Retry command
  local n=1; local max=5; local delay=2
  while true; do
    cgexec -g cpu:cpulimit-${rand} "$@" && break || {
      if [[ $n -lt $max ]]; then
        ((n++))
        echo -e "\e[31m Command failed. Attempt $n/$max \033[0m"
        sleep $delay;
      else
        echo "The command has failed after $n attempts."
        break
      fi
    }
  done
}

if [ $compress = xz ]; then
  if [ $(arch) == 'x86_64' ]; then
    echo "Compressing ${imagename}.img"
    limit_cpu pixz -p 2 ${current_dir}/${imagename}.img # -p Nº cpu cores use
    chmod 644 ${current_dir}/${imagename}.img.xz
  fi
else
  chmod 644 ${current_dir}/${imagename}.img
fi

# Clean up all the temporary build stuff and remove the directories.
# Comment this out to keep things around if you want to see what may have gone
# wrong.
echo "Cleaning up the temporary build files..."
rm -rf "${basedir}"