Re: Building embedded app for host machine


Randy MacLeod
 

On 2022-01-20 10:24, Mauro Ziliani via lists.yoctoproject.org wrote:
Hi all.
I have this doubt.
Is it possible the make a toolchain which can produce the same app for host machine?
I try to explain my think.
I produced an app for imx6dlsabresd with qt-5.6.2 using x86_64 as SDKMACHINE
 Can I make the same app with the same qt-5.6.2 but running directly on x86_64?
Hi,


Yes. Likely you just need to do:
$ MACHINE=qemux86-64 bitbake your-image
with the right configuration and then run it in docker. See below.



There are at least three options depending on what your goal is.

1. use qemux86-64 with kvm support
2. maybe use oe-run-native?
3. as above, build for an intel MACHINE using the linux-dummy kernel.


1. use runqemu -- you might know about this already.

This is how most testing for userspace in Yocto happens.
The default target is qemux86-64 and you boot up a fill VM
that can run graphics as well of course. See the docs or just
run:
$ runqemu help
$ runqemu kvm graphics <other options>

but you don't want the kernel overhead.


2. oe-run-native

Let's deal with the idea of building the -native recipe even though
I suspect it isn't the approach you should take.

See:

https://wiki.yoctoproject.org/wiki/Technical_FAQ#What_does_.22native.22_mean.3F
and examples in oe-core such as:

so for any recipe that inherits 'native', you can run:
$ bitbake app-native

Sometimes there problems with this aside from needing the full dependency tree
to also support -native. There are lots of examples in oe-core of -native recipes:

$ find meta -name "*native*bb" | wc -l

29


Consider quilt:
$ bitbake m4-native
...
$ bitbake quilt-native -c addto_recipe_sysroot
$ oe-run-native quilt-native quilt

Running bitbake -e quilt-native

/usr/lib/python3.6/importlib/_bootstrap.py:219: ImportWarning: can't resolve package from __spec__ or __package__, falling back on __name__ and __path__

return f(*args, **kwds)

Usage: quilt [--trace[=verbose]] [--quiltrc=XX] command [-h] ...

quilt --version

Commands are:

add files import previous series

annotate fold mail push setup

...

And for 'fun' I checked that vim works too:
$ oe-run-native vim-native vim.vim

Anyway, that's just an example and it's really mainly suitable for simple command line apps in my opinion.
I doubt, but haven't checked if any of the recipes in the meta-qt5 layer support being built as -native.


3. docker

The option that makes sense to me is to specify your host system as the
target MACHINE or just use qemux86-64 and build a container image as explained here:

https://pretalx.com/media/oe-workshop-2020/submissions/AN87VC/resources/Building_Containers_with_OpenEmbedded__Cur_WqbQgmv.pdf


Reading the pdf, it seems one can just set this in conf/local.conf:

MACHINE = "qemux86-64"
IMAGE_FSTYPES = "container"
PREFERRED_PROVIDER_virtual/kernel = "linux-dummy"
IMAGE_LINGUAS:append = " en-us"

$ bitbake core-image-minimal

copy the tarball to the system where you have docker working:

laptop$ scp mybuilder:/path/to/build/tmp/deploy/images/qemux86-64/core-image-minimal-qemux86-64.tar.bz2 /tmp
laptop$ docker import /tmp/core-image-minimal-qemux86-64.tar.bz2 core-image-minimal
laptop$ docker run -it core-image-minimal /bin/sh

sh-5.1# cat /etc/os-release
ID=wrlinux
NAME="Wind River Linux development"
VERSION="10.22.03.0"
VERSION_ID=10.22.03.0
PRETTY_NAME="Wind River Linux development 22.03"


Note that I've done this in our WR Linux dev environment but it should just work for any recent Yocto distro.


You can run just one X11 app using:

laptop$ xhost + <-- lets anyone connect to your display so careful.
laptop: docker run -it --rm --privileged --net=host \
--env="DISPLAY" \
--volume="$HOME/.Xauthority:/root/.Xauthority:rw" \
wrlinux-image-std-xfce \
/usr/bin/xfce4-terminal

Careful that you don't inadvertently start a second display manager.
That could really mess up your system input and force you to have to:
$ docker ps
$ docker kill <container-id>
;-)

../Randy


Marketing: WR Linux uses this to make app containers easy:

https://docs.windriver.com/bundle/Wind_River_Linux_Open_Virtualization_Features_Guide_LTS_21/page/xvn1630019013539.html

Now i make this, building the same qt version for host machine, but outside yocto ring
[I hope to be clear, mu english is terrible]
Best regards,
  MZ

--
# Randy MacLeod
# Wind River Linux

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