Wrapper for automating various common jobs while chrooting offline debian based system

chroot-wrapper.sh

#!/bin/bash

target="${1%/}"
[ -z "$target" ] && {
	echo "Wrapper for chroot to set up variables and after use cleanup."
	echo "Usage: $0 target"
	exit 1
}
target="$(realpath "$target")"
[ -d "$target" ] || {
	echo "Target $target does not exist or is not a directory";
	exit 1
}
[ -d "$target/dev" ] && [ -d "$target/run" ] && [ -d "$target/proc" ] && [ -d "$target/sys" ] && [ -d "$target/tmp" ] || {
	echo "Required directories (dev,run,proc,sys,tmp) missing in $target"
	exit 1
}
echo Setting up chroot...
mount -v --bind /dev $target/dev
#mount -v --bind /dev/tty $target/dev/tty
echo Copying files...
mkdir -p $target/root/tmp
cp -L /etc/resolv.conf $target/root/tmp/resolv.conf
[ -e "/run/systemd/resolve/stub-resolv.conf" ] && cp -L /run/systemd/resolve/stub-resolv.conf $target/root/tmp/stub-resolv.conf
[ -e "/run/resolvconf/interface/systemd-resolved" ] && cp -L /run/resolvconf/interface/systemd-resolved $target/root/tmp/systemd-resolved.interface
echo Entering chroot...
chroot $target /bin/bash -c "mount -vt tmpfs none /run
mount -vt proc none /proc
mount -vt sysfs none /sys
mount -vt devpts devpts /dev/pts
mount -vt tmpfs none /dev/shm
mount -vt tmpfs none /tmp
[ -d /var/tmp ] && mount -vt tmpfs none /var/tmp
export LC_ALL=C
echo $target > /etc/debian_chroot
[ -h /var/lock ] && mkdir -vp \"\$(readlink -f /var/lock)\"
if ( type dbus-uuidgen >/dev/null 2>&1 ) ; then
	if [ ! -f \"/var/lib/dbus/machine-id\" ] ; then
		echo Generating dbus machine id.
		dbus-uuidgen --ensure
	else
		echo Skipping dbus machine id generation.
	fi
else
	echo No dbus-uuidgen on this system.
fi
if ( type systemd-machine-id-setup >/dev/null 2>&1 ) ; then
	if [ ! -f \"/etc/machine-id\" ] ; then
		systemd-machine-id-setup
	else
		echo Skipping systemd machine id setup.
	fi
else
	echo No systemd-machine-id-setup on this system.
fi
if ( type resolvconf >/dev/null 2>&1 ) ; then
	echo Setting up resolvconf
	mkdir /run/resolvconf
	#ln -s /run/resolvconf /etc/resolvconf/run
	resolvconf --enable-updates
	if  [ \"\$(ls -A /run/resolvconf/interface/)\" == \"\" ] ; then
		echo No interfaces found: Adding one
		if [ -f /root/tmp/systemd-resolved.interface ] ; then
			cp -v /root/tmp/systemd-resolved.interface /run/resolvconf/interface/systemd-resolved
		else
			cat /root/tmp/resolv.conf > /run/resolvconf/interface/systemd-resolved
		fi
	fi
	resolvconf -u
elif ( type systemd-resolve >/dev/null 2>&1 ) ; then
	echo Running workaround for systemd-resolve
	mkdir -p /run/systemd/resolve/
	cp /root/tmp/stub-resolv.conf /run/systemd/resolve/
else
	if [ ! -e \"/etc/resolv.conf\" ] ; then
		echo Creating new resolv.conf file
		cp /root/tmp/resolv.conf -v /etc/resolv.conf
	elif [ -f /etc/resolv.conf ] ; then
		echo *Found an old resolv.conf on $target*
		du -h /etc/resolv.conf
		cat /etc/resolv.conf
		echo *To be replaced with*
		du -h /root/tmp/resolv.conf
		cat /root/tmp/resolv.conf
		cp -vi /root/tmp/resolv.conf /etc/resolv.conf
	fi
	
fi
if ( type dhclient >/dev/null 2>&1 ) ; then
	read -p \"Dhcp client detected. Enter \\\"y\\\" to run: \" ch
	[ \"\$ch\" == \"y\" ] && dhclient -v
else
	echo No dhclient on this system
fi
echo Cleaning temporary files...
rm /root/tmp/ -rf
if [ -n \"$2\" ]; then
	echo Running shell for user $2...
	su - $2
else
	echo Running root shell...
	su -
fi
echo Cleaning up...
if [ -f \"/var/lib/dbus/machine-id\" ] ; then
	read -p \"Dbus machine id file present. Enter \\\"y\\\" to delete it: \" ch
	[ \"\$ch\" == \"y\" ] && rm -vf /var/lib/dbus/machine-id
fi
if [ -f \"/etc/machine-id\" ] ; then
	read -p \"Systemd machine id file is present. Enter \\\"y\\\" to delete it: \" ch
	[ \"\$ch\" == \"y\" ] && rm -vf /etc/machine-id
fi
if [ -f \"\$HOME/.bash_history\" ] ; then
	read -p \"Bash history file is present. Enter \\\"y\\\" to delete it: \" ch
	[ \"\$ch\" == \"y\" ] && rm -vf \$HOME/.bash_history
fi
rm /etc/debian_chroot
[ -d /var/tmp ] && umount -lfv /var/tmp
umount -lfv /tmp
umount -lfv /dev/shm
umount -lfv /dev/pts
umount -lfv /sys
umount -lfv /run
umount -lfv /proc
echo Leaving chroot..."
#umount -lfv $target/dev/tty
umount -lfv $target/dev
rm -rfv $target/run/*
pstokill="$(lsof 2>/dev/null | grep $target | tr -s "[:space:]" | grep -v ^chroot\- | cut -d\  -f2 | uniq )"
[ -z "$pstokill" ] || {
	echo Terminating remaining processes...
	kill $pstokill
}
pstokill="$(lsof 2>/dev/null | grep $target | tr -s "[:space:]" | grep -v ^chroot\- | cut -d\  -f2 | uniq )"
[ -z "$pstokill" ] || {
	echo Killing remaining processes...
	kill -9 $pstokill
}