[yocto] Transfer meta-data between recipes

[Mark Hatle]

On 9/26/19 8:59 AM, Westermann, Oliver wrote:
> Hey,
> 
>  
> 
> I’m trying to implement a bootloader-signing mechanism within yocto for extended
> secure-boot support. The bootloader and it’s recipes are provided by NXP (in
> this case it’s the imx-boot_*.bb recipe from meta-freescale) and I want to use a
> secondary recipe which I am creating to sign the resulting boot binary. My issue
> is that the NXP code signing tool needs some info about the binary to sign.
> These details are send to stdout by imx-mkimage tool, which is called by the imx
> boot makefile (used here:
> https://github.com/Freescale/meta-freescale/blob/master/recipes-bsp/imx-mkimage/imx-boot_0.2.bb#L104).
> 

In the cases I know of, most code signing is either done in the recipe itself
(via an added task from a special class after install and prior to packaging) or
it's being done at rootfs/image generation time.

> 
> I can override the compile step of imx-boot to save stdout into a file, deploy
> this file and later parse it to extract the offset dump, but that feels “ugly”
> and the file is by no means a output of the imx-boot recipe for the target
> system, but for another step. Is there any recommended way to parse such
> variable metadata between recipes?

Namespace is local to a recipe.  The only way you can share from one namespace
to another is write the data into a file, and then load it in the second.  That
is done occasionally for link time settings and such.  (i.e. pkgconfig).

--Mark

>  
> 
> Olli
> 
>  
> 
>