[OE-core] Contents of non-rootfs partitions

[Maciej Borzęcki]

On Wed, Nov 23, 2016 at 11:12 AM, Enrico Joerns <ejo at pengutronix.de> wrote:
> On 11/23/2016 10:24 AM, Maciej Borzęcki wrote:
>>
<snip>
>
> Yes, what the genimage class (see below) does, is unpacking the final
> rootfs.tar.xz inside a fakeroot environment and call the genimage tool with
> the --rootpath argument set to this path.
>
> The mountpoint="/home" tells genimage to pack all content in directory /home
> into a separate data ext4 image (temporary named 'home.ext4') and all other
> content in a rootfs ext4 image (temporary named 'rootfs.ext4').
>
> The `image` section then specifies how to construct the final disk image
> using the referenced generated rootfs and datafs images (and optionally some
> bootloader, non-partition-data, etc.).
>
>
> Note that this is only one way to use genimage. Another common way to use it
> is to simply construct complex disk images out of different filesystem
> images, e.g. with
>
>   partition barebox {
>           image = "barebox-any-platform.img"
>           size = 1M
>           in-partition-table = false
>   }
>
>> I see there's a large overlap in functionality with wic (at least for
>> block devices), so perhaps the best way would be introduce genimage as
>> another IMAGE_CMD.
>>
>> I've quickly checked at https://layers.openembedded.org and there are no
>> recipes for genimage/libconfuse listed there. Do happen to have done
>> integration with OE in some private repo already? Would it be possible
>> for you to post the relevant patches?
>>
>
> We have a layer for this, which is potentially publicly available but not
> advertised as the general plan was to move some of its content to upstream
> (oe-core, meta-oe) and split up other content (e.g. the rauc update tool
> stuff) to separate layers that will be made publicly available. But, as
> always, there are more plans than time left ;)
>
> Well, to make a long story short, the path to the git repository is:
>
>   https://git.pengutronix.de/cgit/meta-ptx
>
> The genimage class I mentioned above you can find in it, too:
>
>   https://git.pengutronix.de/cgit/meta-ptx/tree/classes/genimage.bbclass
>
>
> When starting with Yocto I thought about changing from genimage to wic for
> disk image creation as wic already seemed to become the standard solution
> for building disk images. But back in these days it was a very separate tool
> and there was no integration with the BSP itself (which is crucial when
> having to reproduce builds). But the main reason why I decided to stay with
> genimage was that wic simply did not cover most of the use cases I required
> for building complex disk images for different embedded platforms. I'm
> pretty sure that this has changed in some points, but had no time to get
> deeper into this topic again, yet.
>
>
> Hope that helps, best regards

Thanks a lot. Very helpful indeed.

-- 
Maciej Borzecki
RnDity