windvn/path/wdvn-image-iso

#!/bin/bash
set -e
DISC_NAME="${WDVN_VER:0:3} $WDVN_ARCH $WDVN_DATE"
DISC_NAME="${DISC_NAME:0:32}"
CHROOT="$1"
IMAGE="$2.tmp"

if [ -d "$IMAGE" ]; then
	rm -r -f "$IMAGE"
fi

EXIT=0
if [ ! -d "$CHROOT/lib/live/boot" ]; then
	echo "ERROR: /lib/live/boot not found within chroot. On your chroot, run 'apt install live-boot'."
	EXIT=1
fi

if [ ! -f "$CHROOT/usr/share/initramfs-tools/hooks/live" ]; then
	echo "ERROR: /usr/share/initramfs-tools/hooks/live not found within chroot. On your chroot, run 'apt install live-boot-initramfs-tools'."
	EXIT=1
fi

if ! command -v mksquashfs &> /dev/null
then
	echo "ERROR: mksquashfs not found. Run 'apt install squashfs-tools'."
	EXIT=1
fi

if ! command -v xorriso &> /dev/null
then
	echo "ERROR: xorriso not found. Run 'apt install xorriso'."
	EXIT=1
fi

if ! command -v grub-mkrescue &> /dev/null
then
        echo "ERROR: grub-mkrescue not found. Run 'apt install grub-common'."
        EXIT=1
fi

if [ -f "$2" ]; then
	echo "ERROR: $2 already exists."
	EXIT=1
fi

if [ "$EXIT" == "1" ]; then
	exit 1
fi

mkdir -p "$IMAGE"
mkdir -p "$IMAGE/live"
mkdir -p "$IMAGE/boot/grub"

cp -fv "$CHROOT/boot"/vmlinuz-* "$IMAGE/live/vmlinuz"
cp -fv "$CHROOT/boot"/initrd.img-* "$IMAGE/live/initrd.img"
mksquashfs "$CHROOT" "$IMAGE/live/filesystem.squashfs"
#mksquashfs -comp zstd -Xcompression-level 22 "$CHROOT" "$IMAGE/live/filesystem.squashfs"

echo "GRUB_TERMINAL=console

menuentry '$WDVN_NAME $WDVN_ARCH $WDVN_VER $WDVN_DATE live' --class gnu-linux --id linux {
	insmod all_video
	echo "Loading Linux ..."
	linux /live/vmlinuz boot=live noautologin quiet
	echo "Loading initrd ..."
	initrd /live/initrd.img
}
" > "$IMAGE/boot/grub/grub.cfg"

grub-mkrescue -o "$2" "$IMAGE" --volid "$DISC_NAME"

rm -r "$IMAGE"