Custom Ubuntu Image Builder scripts

_enter.sh

#!/bin/bash

mount -t proc none /proc
mount -t sysfs none /sys
mount -t devpts none /dev/pts
export HOME=/root
export LC_ALL=C
dbus-uuidgen > /var/lib/dbus/machine-id
dpkg-divert --local --rename --add /sbin/initctl
ln -s /bin/true /sbin/initctl

_leave.sh

#!/bin/bash

apt autoremove -y
apt clean -y
rm -rf /tmp/* ~/.bash_history /enter.sh /leave.sh
rm /var/lib/dbus/machine-id
rm /sbin/initctl
dpkg-divert --rename --remove /sbin/initctl
umount /proc || umount -lf /proc
umount /sys
umount /dev/pts

build.sh

#!/bin/bash

DIST=bionic
NAME=Custom
FILE=output.iso
KEY=$CUSTOM_ISO_KEY
PASS=$CUSTOM_ISO_PASSPHRASE

rm $FILE

cd extract
apt-ftparchive packages ./pool/main/ > dists/stable/main/binary-amd64/Packages
apt-ftparchive packages ./pool/restricted/ > dists/stable/restricted/binary-amd64/Packages
apt-ftparchive packages ./pool/extras/ > dists/stable/extras/binary-amd64/Packages
gzip -c dists/stable/main/binary-amd64/Packages | tee dists/stable/main/binary-amd64/Packages.gz > /dev/null
gzip -c dists/stable/restricted/binary-amd64/Packages | tee dists/stable/restricted/binary-amd64/Packages.gz > /dev/null
gzip -c dists/stable/extras/binary-amd64/Packages | tee dists/stable/extras/binary-amd64/Packages.gz > /dev/null
apt-ftparchive -c ../apt-ftparchive/release.conf generate ../apt-ftparchive/apt-ftparchive-deb.conf
apt-ftparchive -c ../apt-ftparchive/release.conf generate ../apt-ftparchive/apt-ftparchive-udeb.conf
apt-ftparchive -c ../apt-ftparchive/release.conf generate ../apt-ftparchive/apt-ftparchive-extras.conf
apt-ftparchive -c ../apt-ftparchive/release.conf release dists/stable > dists/stable/Release
rm dists/stable/Release.gpg
echo $PASS | gpg --pinentry-mode loopback --batch --yes --passphrase-fd 0 --default-key "$KEY" --output dists/stable/Release.gpg -ba dists/stable/Release
find . -type f -print0 | xargs -0 md5sum > md5sum.txt
cd ../
umount edit/dev
chmod +w extract/install/filesystem.manifest
chroot edit dpkg-query -W --showformat='${Package} ${Version}\n' | tee extract/install/filesystem.manifest
rm extract/install/filesystem.squashfs extract/install/filesystem.size
printf $(du -sx --block-size=1 edit | cut -f1) | tee extract/install/filesystem.size
mksquashfs edit extract/install/filesystem.squashfs -b 1048576
cd extract
rm md5sum.txt
find -type f -print0 | sudo xargs -0 md5sum | grep -v isolinux/boot.cat | tee md5sum.txt
genisoimage -D -r -V "$NAME" -cache-inodes -J -l -b isolinux/isolinux.bin -c isolinux/boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table -o ../$FILE .
cd ..

enter.sh

#!/bin/bash

cp /etc/resolv.conf edit/etc/
cp _enter.sh edit/enter.sh
cp _leave.sh edit/leave.sh
chmod +x edit/enter.sh edit/leave.sh

mount --bind /dev/ edit/dev

chroot edit