scripts/debian/chroot.mount

#!/bin/sh

# Vars
## Define the hard drive to use
if [ -b '/dev/sda' ]; then
	hdd="/dev/sda"
else
	printf '%b\n' "Please check the hard drive to use"
	exit 0
fi

## If empty, the script will try to get one with nslookup
new_hostname=""
## Try to guess the VG name by using the last VG detected
vgname=$(vgdisplay --short | tail -n 1 | sed 's/.*"\(.*\)" .*/\1/')
## If the script should create extra volume (eg. backup, virt, Proxmox,…)
manage_extra_lv=0
## Is BTRFS {{{
root_fs_type=$(lsblk -f /dev/mapper/"${vgname}"-root | awk '/root/ { print $2 }')
if [ "${root_fs_type}" = "btrfs" ]; then
	manage_btrfs=0
else
	manage_btrfs=1
fi
## }}}
## Colors definition {{{
BLACK='\033[49;30m'
BLACKB='\033[49;90m'
RED='\033[0;31m'
REDB='\033[1;31m'
GREEN='\033[0;32m'
YELLOW='\033[0;33m'
BLUE='\033[94;49m'
MAGENTA='\033[0;35m'
CYAN='\033[36;49m'
WHITE='\033[0;37m'
BOLD='\033[1m'
RESET='\033[0m'
## }}}

## Dependencies {{{
apt update
apt install ipcalc
## }}}

## Mount the system {{{
### Root
mkdir -p -- /target
mountpoint -q /target            || mount -- /dev/mapper/"${vgname}"-root /target

	### boot - grub
	mountpoint -q /target/boot       || mount -- ${hdd}1 /target/boot
##
if [ "${manage_btrfs}" -eq 0 ]; then
	printf '%b\n' "The root system is in ${GREEN}BTRFS${RESET}, no extra mount is required."
else
	#### home LV
	mountpoint -q /target/home       || mount -- /dev/mapper/"${vgname}"-home /target/home
	#### opt LV
	mountpoint -q /target/opt        || mount -- /dev/mapper/"${vgname}"-opt /target/opt
	#### srv LV
	mountpoint -q /target/srv        || mount -- /dev/mapper/"${vgname}"-srv /target/srv
	#### tmp LV
	mountpoint -q /target/tmp        || mount -- /dev/mapper/"${vgname}"-tmp /target/tmp
	#### usr LV
	mountpoint -q /target/usr        || mount -- /dev/mapper/"${vgname}"-usr /target/usr
	#### var LV
	mountpoint -q /target/var        || mount -- /dev/mapper/"${vgname}"-var /target/var

	if [ "${manage_extra_lv}" -eq 0 ]; then
		### Extra bkp LV
		mountpoint -q /target/srv/backup || mount -- /dev/mapper/"${vgname}"-bkp /target/srv/backup
		### Extra vz LV
		mountpoint -q /target/var/lib/vz || mount -- /dev/mapper/"${vgname}"-vz /target/var/lib/vz
	fi
fi

### Swap
swapon -- /dev/mapper/"${vgname}"-swap
## }}}
## Ensure to (re)mount devices for chroot {{{
mkdir -p --   /target/dev
mountpoint -q /target/dev        || mount -t devtmpfs -- none      /target/dev
mkdir -p --   /target/dev/pts
mountpoint -q /target/dev/pts    || mount -t devpts   -- /dev/pts  /target/dev/pts
mkdir -p --   /target/proc
mountpoint -q /target/proc       || mount -t proc     -- none      /target/proc
mkdir -p --   /target/sys
mountpoint -q /target/sys        || mount -t sysfs    -- none      /target/sys
### FIXME : /run/lvm needs to be manually set in debootstrap|chroot for Buster {{{
### See :
### https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=918590
### https://bbs.archlinux.org/viewtopic.php?pid=1820949#p1820949
mkdir -p --   /target/run/lvm
mountpoint -q /target/run/lvm    || mount --bind      -- /run/lvm  /target/run/lvm
mkdir -p --   /target/run/udev
mountpoint -q /target/run/udev   || mount --bind      -- /run/udev /target/run/udev
### }}}
## }}}

## Network {{{
### Get all informations from current network configuration in rescue mode
net_device=$(ip r | grep "^default" | head -1 | cut -d" " -f5)
#### TODO: Switch to ip a to get ip address
net_address=$(ip r | grep -vE "(^default|metric)" | grep "${net_device}.*src" | head -1 | awk -F" " '{print $NF}')
read -r net_mac_address </sys/class/net/"${net_device}"/address
net_netmask=$(ipcalc "${net_address}" | awk '/Netmask:/{print $2;}')
net_netmask_cidr=$(ipcalc "${net_address}" | awk '/Netmask:/{print $4;}')
net_broadcast=$(ip a s dev "${net_device}" | awk '/inet.*brd/{print $4}')
net_network=$(ip r | grep -vE "(^default|metric)" | grep "src ${net_address}" | head -1 | cut -d"/" -f1)
net_gateway=$(ip r | grep "^default" | head -1 | cut -d" " -f3)

### Create a network unit for systemd-networkd
printf '%b' "[Match]
MACAddress=${net_mac_address}

[Network]
Description=network interface with default route without dhcp
DHCP=no
Address=${net_address}/${net_netmask_cidr}
Gateway=${net_gateway}
IPv6AcceptRA=no
DNS=80.67.169.12
" > /tmp/50-default.network

## }}}

printf '%b\n' "${GREEN}The system is available on /target you can now try to chroot.${RESET}"

exit 0