environment/bin/make-winux

#!/usr/bin/env zsh

export LINUX_DISK_IMG=/home/artur/winux/VM/linux/linux.img
export WINUX_DISK_IMG=./winux.img

# Mount the image of oryginal 
#

# Mounting the image
function wxumount {
  echo "unmounting :$1"
    mkdir -p $1
    if mountpoint -q $1; then
        echo "Unmounting $1..."
        umount /mnt/winux
        if [ $? -eq 0 ]; then
            echo "Successfully unmounted $1."
        else
            echo "Failed to unmount $1."
        fi
    else
        echo "$1 is not mounted."
    fi
}

wxumount /mnt/winux
wxumount /mnt/linux

# (re)create an empty sparsed file
rm -rf $WINUX_DISK_IMG
dd if=/dev/zero of=$WINUX_DISK_IMG bs=1 count=0 seek=20G

# Check size
# real size: du -h winux.img
# appeared as: ls -lh winux.img


# Copy boot 

IMG="/home/artur/winux/VM/linux/linux.img"

SECTOR_SIZE=$(LC_ALL=C sfdisk -d "$LINUX_DISK_IMG" | awk 'match($0,/sector-size:\s*([0-9]+)/,m){print m[1]; exit}')
START=$(LC_ALL=C sfdisk -d "$LINUX_DISK_IMG" | awk 'match($0,/start=\s*([0-9]+)/,m){print m[1]; exit}')

echo "Sector size: $SECTOR_SIZE"
echo "Start sector: $START"


dd if="$LINUX_DISK_IMG" of="$WINUX_DISK_IMG" bs="$SECTOR_SIZE" count="$START" conv=notrunc

# Formatting the disk
# No altering the first 1MB
echo '2048,,83,*' | sudo sfdisk --no-reread $WINUX_DISK_IMG

# List all loops: sudo losetup -a
WINUX_LOOP_DEV=$(sudo losetup --find --show $WINUX_DISK_IMG)
# Scan also for partitions: sudo losetup --find --show --partscan winux.img

echo "Loop device: $WINUX_LOOP_DEV"



export WINUX_LOOP_DEV="$(losetup --find --show -P $WINUX_LOOP_DEV)"

mkfs.ext2 ${WINUX_LOOP_DEV}p1

mount ${WINUX_LOOP_DEV}p1 /mnt/winux

## The image is formatted and ready to copy files over


export LINUX_LOOP_DEV="$(losetup --find --show --partscan $LINUX_DISK_IMG)"
mount ${LINUX_LOOP_DEV}p1 /mnt/linux


# copying files 

cd /mnt/linux
tar --numeric-owner --xattrs --acls -cpf - \
  --exclude='lost+found' \
  --exclude='var/log/*' \
  --exclude='var/tmp/*' \
  --exclude='tmp/*' \
  --exclude='var/cache/*' \
  --exclude='swapfile' \
  --exclude='dev/*' \
  --exclude='proc/*' \
  --exclude='sys/*' \
  --exclude='run/*' \
  . | tar --numeric-owner --xattrs --acls -xpf - -C /mnt/winux



#### TESTTING CODE
losetup -j $WINUX_DISK_IMG

# Clean up after building 

wxumount /mnt/winux
wxumount /mnt/linux

for dev in $(losetup -j $WINUX_DISK_IMG | cut -d: -f1); do
  losetup -d "$dev"
done

for dev in $(losetup -j $LINUX_DISK_IMG | cut -d: -f1); do
  losetup -d "$dev"
done


# Create an archive
#

# echo "making the archive"
# zstd -T0 --ultra -22 winux.img -o winux.img.zst

# # decompression with 
# # unzstd --sparse winux.img.zst
# # or
# # zstd -d --sparse winux.img.zst -o winux.img

############# Another option, seems to be the best option

tar --sparse -I 'zstd -T0 --ultra -22 --long=31' \
  -cvf winux.img.tar.zst winux.img
# extract
# brew install gnu-tar
# tar -I zstd -xvf winux.img.tar.zst
# on macOS  /opt/homebrew/opt/gnu-tar/libexec/gnubin/tar -I 'zstd --long=31' -xvf winux.img.tar.zst winux.img

# compressing with XZ. Supprisely it seems to have worst compresion rate than zstd

# tar --sparse -I 'xz -T0 -9e' -cvf winux.img.tar.xz winux.img
## Extracting
# tar -I xz -xvf winux.img.tar.xz