Webdm not working with 64bits Kernel and 32bits User Space: "$plat_abi=aarch64-linux-gnu" & "/snap/webdm/current/bin arm-linux-gnueabihf"

[Pedro Coca]

Webdm not working with 64bits Kernel and 32bits User Space: "$plat_abi=aarch64-linux-gnu" & "/snap/webdm/current/bin arm-linux-gnueabihf"

root@localhost:~# uname -i
aarch64

root@localhost:~# ls /snap/webdm/current/bin
arm-linux-gnueabihf

root@localhost:~# cat /snap/webdm/current/snappyd | grep exec
exec $SNAP/bin/$plat_abi/snappyd

=====================================================================

root@localhost:~# cat /snap/webdm/current/snappyd
#!/bin/sh
set -e

platform=$(uname -i)

case $platform in
    x86_64)
        plat_abi=x86_64-linux-gnu
        ;;
    armv7l)
        plat_abi=arm-linux-gnueabihf
        ;;
    aarch64)
        plat_abi=aarch64-linux-gnu
        ;;
    *)
        echo "unknown platform for snappy-magic: $platform. remember to file a bug or better yet: fix it :)"
        ;;
esac

exec $SNAP/bin/$plat_abi/snappyd

# never reach this
exit 1

=====================================================================

so
$plat_abi = aarch64-linux-gnu
and
/snap/webdm/current/bin contains arm-linux-gnueabihf

[Steven Wilkin (stevenwilkin)]

This is possibly due to the wrong version of the snap being uploaded to the store for the architecture or a problem with how `snap install` determines the architecture.

Could you try building from source and seeing if the resulting arm64 snap works? The project is now located here:

https://github.com/snapcore/snapweb

I've also a branch which uses `snapcraft` to construct the snap which may be more useful:

https://github.com/snapcore/snapweb/tree/snapcraft

[Michael Vogt (mvo)]

What version of snappy/snapd is used for this?

Could you please paste the output of:
$ snap list

I think the wrapper script is actually wrong here, it should not check the kernel (uname -i) but instead the go architecture. With the latest code where we do not use a "fat" binary we should probably just change the build script.
In the meantime `dpkg --print-architecture` (while we still have it) might be enough.
Thanks,
 Michael

[Yann Sionneau (yann-sionneau)]

Yes exactly, the issue is the wrapper script which checks the kernel arch instead of the user space one.
root@localhost:~# dpkg --print-architecture
armhf
root@localhost:~# uname -i
aarch64

[Yann Sionneau (yann-sionneau)]

In fact I think we should use SNAP_ARCH environment variable.

[Steven Wilkin (stevenwilkin)]

I've a work-in-progress PR open to use Snapcraft to build the snap. It removes all cross-building concerns from this project with the intention that the Launchpad build farm will build for all supported architectures and upload to the store on the edge channel automatically.

[Jamie Bennett (jamiebennett)]

There have been changes to the build script lately, can you please retest with the latest version of snapweb?