edim

#!/bin/bash

if [ -z $1 ]||[ $1 == "-h" ]||[ $1 == "-help" ]||[ $1 == "--help" ]; then
    echo "
## Crome Os -like empty disk image maker
## It creates a disk image with kernel and root partitions only,
## for other scheme use cgpt manually.
##
## use: $0 'dsk size in Mb '
## or: sudo $0 'dsk size in Mb ' 'root file system type'
##
## requires: kpartx, cgpt, mkfs.btrfs, mkfs.f2fs or mkfs.ext4 for specified fs
##
## 'WARNING: Primary GPT header is invalid' and
## 'WARNING: Secondary GPT header is invalid'
## is normal for chromeos disks
"
    exit 1
fi
if [ $1 -le 1023 ]; then
    echo "
    disk size is too small, specify 1024 or more
    "
    exit 1
fi
if [ $(whoami) == root ] ; then
    if [ -z $2 ] || $(echo btrfs f2fs ext4 | grep -vq $2); then
        echo "
    specify btrfs or f2fs or ext4 like: $0 $1 btrfs
    "
        exit 1
    fi
fi
if $(parted -h 2>&1 | grep -q 'command not found'); then
    echo '
    parted is required
    '
    exit 1
fi
if $(kpartx 2>&1 | grep -q 'command not found'); then
    echo '
    kpartx is required
    '
    exit 1
fi
if $(cgpt 2>&1 | grep -q 'command not found'); then
    echo '
    cgpt is required
    '
    exit 1
fi

basedir=$PWD

dd if=/dev/zero of=${basedir}/xe303c12_disk.img bs=1M count=$1
parted xe303c12_disk.img --script -- mklabel gpt
cgpt create -z xe303c12_disk.img
cgpt create xe303c12_disk.img
cgpt add -i 1 -t kernel -b 8192 -s 32768 -l kernel -S 1 -T 5 -P 10 xe303c12_disk.img
cgpt add -i 2 -t data -b 40960 -s `expr $(cgpt show xe303c12_disk.img | grep 'Sec GPT table' | awk '{ print \$1 }')  - 40960` -l Root xe303c12_disk.img

if [ $(whoami) == root ] ; then
    
    loopdevice=`losetup -f --show ${basedir}/xe303c12_disk.img`
    device=`kpartx -va $loopdevice| sed -E 's/.*(loop[0-9])p.*/\1/g' | head -1`
    sleep 5
    device="/dev/mapper/${device}"
    bootp=${device}p1
    rootp=${device}p2

    mkdir -p ${basedir}/root
    if [ "$2" == "btrfs" ]; then
        mkfs.btrfs -f --label rootfs $rootp
        mount $rootp ${basedir}/root -o,compress=zstd:5
    elif [ "$2" == "f2fs" ]; then
        mkfs.f2fs -f -O 'extra_attr flexible_inline_xattr compression encrypt ' -l rootfs $rootp
        mount $rootp ${basedir}/root -o,compress_algorithm=lzo,compress_extension=*
    else
        mkfs.ext4 -O ^flex_bg -O ^metadata_csum -L rootfs $rootp
        mount $rootp ${basedir}/root
    fi

    rootuuid=$(LANG=C blkid | grep "$rootp" | grep 'LABEL="rootfs"' | sed 's/.* UUID="//g' | sed 's/".*//g')

    if [ ! -d ${basedir}/root/etc ]; then
        mkdir -p ${basedir}/root/etc
    fi

    if [ "$2" == "btrfs" ]; then
cat << EOF> ${basedir}/root/etc/fstab
# /etc/fstab: static file system information.
#
# Use 'blkid' to print the universally unique identifier for a
# device; this may be used with UUID= as a more robust way to name devices
# that works even if disks are added and removed. See fstab(5).
#
# <file system> <mount point>   <type>  <options>       <dump>  <pass>
# / was on /dev/sda2 during installation
UUID=$rootuuid /               btrfs    rw,noatime,compress=zstd:5,ssd 0       0
# swap was on /dev/sdaX during installation
#UUID= none            swap    sw              0       0
#/dev/sr0        /media/cdrom0   udf,iso9660 user,noauto     0       0
EOF
    elif [ "$2" == "f2fs" ]; then
cat << EOF> ${basedir}/root/etc/fstab
# /etc/fstab: static file system information.
#
# Use 'blkid' to print the universally unique identifier for a
# device; this may be used with UUID= as a more robust way to name devices
# that works even if disks are added and removed. See fstab(5).
#
# <file system> <mount point>   <type>  <options>       <dump>  <pass>
# / was on /dev/sda2 during installation
UUID=$rootuuid /               f2fs    rw,noatime,compress_algorithm=zstd,compress_extension=* 0       1
# swap was on /dev/sdaX during installation
#UUID= none            swap    sw              0       0
#/dev/sr0        /media/cdrom0   udf,iso9660 user,noauto     0       0
EOF
    else
cat << EOF> ${basedir}/root/etc/fstab
# /etc/fstab: static file system information.
#
# Use 'blkid' to print the universally unique identifier for a
# device; this may be used with UUID= as a more robust way to name devices
# that works even if disks are added and removed. See fstab(5).
#
# <file system> <mount point>   <type>  <options>       <dump>  <pass>
# / was on /dev/sda2 during installation
UUID=$rootuuid /               ext4    rw,noatime 0       1
# swap was on /dev/sdaX during installation
#UUID= none            swap    sw              0       0
#/dev/sr0        /media/cdrom0   udf,iso9660 user,noauto     0       0
EOF
    fi
    
    echo "to unmount root run
    sudo umount root
to flash kernel_image run
    sudo dd if='path to kernel_image' of=$bootp
to remove loop devices run
    sudo kpartx -dv $loopdevice
    sudo losetup -d $loopdevice"
else
    echo '
    root rights was not granted, you can format and mount the partitions manually
    '
fi