# vi: ts=4 expandtab syntax=sh

CLOUD_IMG_STR="# CLOUD_IMG: This file was created/modified by the Cloud Image build process"
IMAGE_SIZE=$((2252*1024**2))  # 2.2G (the current size we ship)

rootfs_dev_mapper=
loop_device=
loop_raw=

clean_loops() {
    [ -z "${rootfs_dev_mapper}" ] || {
        udevadm settle
        find /dev/mapper -iname "${loop_device///dev\//}*" | \
            xargs -n1 -I DEVICE dmsetup remove DEVICE ||
                kpartx -d "${rootfs_dev_mapper}"
        losetup -d "${loop_device}" || echo "Failed to detach disk"
        unset loop_raw
    }
}

create_empty_disk_image() {
    # Prepare an empty disk image
    dd if=/dev/zero of="$1" bs=1 count=0 seek="${IMAGE_SIZE}"
}

make_ext4_partition() {
    device="$1"

    mkfs.ext4 -F -b 4096 -i 8192 -m 0 -L cloudimg-rootfs -E resize=536870912 "$device"
}

mount_image() {
    apt-get install -qqy kpartx
    trap clean_loops EXIT
    loop_raw="$(kpartx -s -v -a "$1" )"
    loop_device="$(echo -e "${loop_raw}" | head -n1 | awk '{print($(NF-1))}')"
    rootfs_dev_mapper="/dev/mapper${loop_device///dev/}p1"
    [ ! -b "${rootfs_dev_mapper}" ] &&
        echo "${rootfs_dev_mapper} is not a block device" && exit 1
    return 0
}

mount_partition() {
    partition="$1"
    mountpoint="$2"

    mount "$partition" "$mountpoint"
    mount --bind /dev "$mountpoint/dev"
    mount proc-live -t proc "$mountpoint/proc"
    mount sysfs-live -t sysfs "$mountpoint/sys"
    mv "$mountpoint/etc/resolv.conf" resolv.conf.tmp
    cp /etc/resolv.conf "$mountpoint/etc/resolv.conf"
}

umount_partition() {
    mountpoint="$1"

    mv resolv.conf.tmp "$mountpoint/etc/resolv.conf"
    umount "$mountpoint/proc"
    umount "$mountpoint/sys"
    umount "$mountpoint/dev"
    umount "$mountpoint"
}

modify_vmdk_header() {
    # Modify the VMDK headers so that both VirtualBox _and_ VMware can
    # read the vmdk and import them. The vodoo here is _not_ documented
    # anywhere....so this will have to do. This is undocumented vodoo
    # that has been learned by the Cloud Image team.

    vmdk_name="${1}"
    descriptor=$(mktemp)
    newdescriptor=$(mktemp)

    # Extract the vmdk header for manipulation
    dd if="${vmdk_name}" of="${descriptor}" bs=1 skip=512 count=1024

    # The sed lines below is where the magic is. Specifically:
    #   ddb.toolsVersion: sets the open-vm-tools so that VMware shows
    #       the tooling as current
    #   ddb.virtualHWVersion: set the version to 7, which covers most
    #       current versions of VMware
    #   createType: make sure its set to stream Optimized
    #   remove the vmdk-stream-converter comment and replace with
    #       # Disk DescriptorFile. This is needed for Virtualbox
    #   remove the comments from vmdk-stream-converter which causes
    #       VirtualBox and others to fail VMDK validation

    sed -e 's|# Description file.*|# Disk DescriptorFile|' \
        -e '/# Believe this is random*/d' \
        -e '/# Indicates no parent/d' \
        -e '/# The Disk Data Base/d' \
        -e 's|ddb.comment.*|ddb.toolsVersion = "2147483647"|' \
            "${descriptor}" > "${newdescriptor}"

    # The header is cannot be bigger than 1024
    expr $(stat --format=%s ${newdescriptor}) \< 1024 > /dev/null 2>&1 || {
        echo "descriptor is too large, VMDK will be invalid!"; exit 1; }

    # Overwrite the vmdk header with our new, modified one
    dd conv=notrunc,nocreat \
        if="${newdescriptor}" of="${vmdk_name}" \
        bs=1 seek=512 count=1024

    rm ${descriptor} ${newdescriptor}
}

create_vmdk() {
    # There is no real good way to create a _compressed_ VMDK using open source
    # tooling that works across multiple VMDK-capable platforms. This functions
    # uses vmdk-stream-converter and then calls modify_vmdk_header to produce a
    # compatible VMDK.

    src="$1"
    destination="$2"
    size="${3:-10240}"

    apt-get install -qqy qemu-utils vmdk-stream-converter
    streamconverter="/usr/share/pyshared/VMDKstream.py"
    scratch_d=$(mktemp -d)
    cp ${src} ${scratch_d}/resize.img

    truncate --size=${size}M ${scratch_d}/resize.img
    python ${streamconverter} ${scratch_d}/resize.img ${destination}
    modify_vmdk_header ${destination}

    qemu-img info ${destination}
    rm -rf ${scratch_d}
}