Sets up an x86 environment within an your arm based debian pc from which you could run x86 apps

install_envx86.sh

#!/bin/bash

#=================================================================================================#
#install_envx86.sh
#----------
#by: ilobmirt @ 2022_JAN_25
#
#Sets up an x86 environment within an your arm based pc from which you could run x86 apps
#=================================================================================================#

install_target="/env_x86"
install_environment="i386"

scripts_install_target="/opt/envx86"
script_mount_file="envmount"
script_env_cmd_file="envx86_prompt"

desktop_install_target="$HOME/.local/share/applications/"

mount_host_sys="/sys"
mount_host_proc="/proc"
mount_host_dev="/dev"
mount_host_pts="/dev/pts"
mount_host_shm="/dev/shm"

mount_target_sys="$install_target/sys/"
mount_target_proc="$install_target/proc/"
mount_target_dev="$install_target/dev/"
mount_target_pts="$install_target/dev/pts/"
mount_target_shm="$install_target/dev/shm/"

main_install_packages(){
	sudo apt-get update
	local installed_packages=$(apt list --installed)
	local to_install=""
	local does_exist=""
	for input_package in $@
	do
		does_exist=$(echo "$installed_packages" | grep "$input_package/")
		if [ -z "$does_exist" ]; then
			echo "Package $input_package not found, adding to list of packages"
			to_install="$to_install $input_package"
		else
			echo "Package $input_package is already installed"
		fi
	done

	if [ ! -z "$to_install" ]; then
		echo "Installing $to_install"
		sudo apt-get install$to_install -y
	else
		echo "Nothing found to install"
	fi
}

env_link(){
	sudo mount -t sysfs $mount_host_sys $mount_target_sys
	sudo mount -t proc $mount_host_proc $mount_target_proc
	sudo mount --bind $mount_host_dev $mount_target_dev
	sudo mount --bind $mount_host_pts $mount_target_pts
	sudo mount --bind $mount_host_shm $mount_target_shm
}

env_build(){
	local debian_version=$(lsb_release -c -s)
	local qemu_file="qemu-i386-static"
	if [ -d "$install_target" ]; then
		sudo umount $mount_target_sys
		sudo umount $mount_target_proc
		sudo umount $mount_target_pts
		sudo umount $mount_target_shm
		sudo umount $mount_target_dev
		sudo rm -rf $install_target
	fi
	sudo debootstrap --foreign --arch $install_environment $debian_version $install_target
	env_link
	sudo cp /usr/bin/$qemu_file $install_target/usr/bin/
	sudo chroot $install_target/ /debootstrap/debootstrap --second-stage
}

env_cmd(){
	local username_given=$1
	local command_given=$2
	sudo chroot $install_target/ /bin/su $username_given --command="$command_given"
}

env_install_packages(){
	env_cmd root "apt-get update"
	local installed_packages=$(env_cmd root "apt list --installed")
	local to_install=""
	local does_exist=""
	for input_package in $@
	do
		does_exist=$(echo "$installed_packages" | grep "$input_package/")
		if [ -z "$does_exist" ]; then
			echo "Package $input_package not found, adding to list of packages"
			to_install="$to_install $input_package"
		else
			echo "Package $input_package is already installed"
		fi
	done

	if [ ! -z "$to_install" ]; then
		echo "Installing $to_install"
		env_cmd root "apt-get install$to_install -y" 
	else
		echo "Nothing found to install"
	fi
}

env_setup_bashrc(){
	local username_given=$1
	local file_append="
export LANGUAGE=\\\"C\\\"
export LC_ALL=\\\"C\\\"
export DISPLAY=:0
"

	env_cmd $username_given "echo \"$file_append\" >> ~/.bashrc ; source ~/.bashrc"

}

main_install_service_mount(){
	local script_path="$scripts_install_target"
	local script_file_name="$script_mount_file"
	local script_file_contents="#!/bin/bash
sudo mount -t sysfs $mount_host_sys $mount_target_sys
sudo mount -t proc $mount_host_proc $mount_target_proc
sudo mount --bind $mount_host_dev $mount_target_dev
sudo mount --bind $mount_host_pts $mount_target_pts
sudo mount --bind $mount_host_shm $mount_target_shm"

	local service_path="/etc/systemd/system"
	local service_file_name="envx86.mount.service"
	local service_file_contents="
[Unit]
Description= mounts the x86 environment for use with chroot

[Service]
Type=one-shot
ExecStart=$script_path/$script_file_name

[Install]
WantedBy=multi-user.target
"

	if [ ! -d "$script_path" ]; then
		sudo mkdir $script_path
	fi
	sudo sh -c "echo \"$script_file_contents\" > $script_path/$script_file_name"
	sudo chmod +x $script_path/$script_file_name 	
	sudo sh -c "echo \"$service_file_contents\" > $service_path/$service_file_name"
	sudo systemctl enable $service_file_name
}

main_install_env_prompt(){
	local script_path="$scripts_install_target"
	local script_file_name="$script_env_cmd_file"
	local script_file_contents="#!/bin/bash
/usr/sbin/chroot $install_target/ /bin/su -l \\\$1"

	if [ ! -d "$script_path" ]; then
		sudo mkdir $script_path
	fi
	sudo sh -c "echo \"$script_file_contents\" > $script_path/$script_file_name"
	sudo chmod +x $script_path/$script_file_name
}

main_install_cmd_desktop(){
	local install_path="$desktop_install_target"
	local file_name="x86_$1.desktop"
	local file_contents="[Desktop Entry]
Encoding=UTF-8
Version=1.0
Comment=Start an x86 user environment
Type=Application
Terminal=false
Exec=xterm -e sudo $scripts_install_target/$script_env_cmd_file $1
Name=CMD $1 x86"

echo "$file_contents" > $install_path/$file_name
}

env_add_user(){
	local username_given=$1
	local password_given=$2
	local local_uid=$(id $username_given -u)
	local local_groups=$(id $username_given -nG)
	
	env_cmd root "useradd -m -p \$(mkpasswd -m sha-512 \"$password_given\") -s /bin/bash $username_given"
	for group_add in $local_groups
	do
		env_cmd root "usermod -a -G $group_add $username_given 2> /dev/null"
	done

	env_setup_bashrc $username_given

}

main(){
	local install_username=$USER
	local install_password="power_up"
	main_install_packages qemu qemu-user qemu-user-static binfmt-support debootstrap binutils
	env_build
	env_setup_bashrc root
	env_install_packages sudo whois x11-apps neofetch cabextract winbind wget xz-utils
	env_add_user $install_username $install_password
	main_install_service_mount
	main_install_env_prompt
	main_install_cmd_desktop root
	main_install_cmd_desktop $install_username
	env_cmd $install_username "mkdir ~/Downloads"
	env_cmd $install_username "neofetch"
	env_cmd $install_username "xeyes &"
	echo ""
	echo "==================="
	echo "|CONGRATULATIONS! |"
	echo "==================="	
	echo "$install_environment environment has been installed under \"$install_target\"!"
	echo "If successful, you should see neofetch reporting that it is running $install_environment software"
	echo "Also, if x11 is configured correctly, you should see xeyes present on the host desktop"
	echo ""
	echo "==================="
	echo "|NOTE:            |"
	echo "==================="
	echo "The $install_environment environment user - $install_username has been installed with a default password \"$install_password\""
	echo "Consider changing it with the passwd command once you use that account"
}

main