xenomai4 - running applications as regular user

xenomai4 - running applications as regular user

[Emmanuel Pacaud]

Hi,

What is the recommended way to run out of band applications as regular user using xenomai4 ?

In xenomai3 documentation, there is a dedicated page about this, <https://v3.xenomai.org/tips/regular-user/>, but I did not find similar instructions in xenomai4 version.

Emmanuel.

Re: xenomai4 - running applications as regular user

[Philippe Gerum]

Emmanuel Pacaud <emmanuel.pacaud@lapp.in2p3.fr> writes:

> [1. text/markdown]
> Hi,
>
> What is the recommended way to run out of band applications as regular user using xenomai4 ?
>
> In xenomai3 documentation, there is a dedicated page about this, <https://v3.xenomai.org/tips/regular-user/>, but I did not find similar instructions in xenomai4 version.
>
> Emmanuel.

See https://v4.xenomai.org/core/user-api/#device-ownership-and-access

-- 
Philippe.

Re: xenomai4 - running applications as regular user

[Emmanuel Pacaud]

Le vendredi 22 août 2025 à 09:13 +0200, Philippe Gerum a écrit :
> 
> > What is the recommended way to run out of band applications as regular user using xenomai4 ?
> > 
> > In xenomai3 documentation, there is a dedicated page about this, <[https://v3.xenomai.org/tips/regular-user/](https://v3.xenomai.org/tips/regular-user/)>, but I did not find similar instructions in xenomai4 version.
> > 
> > Emmanuel.
> 
> 
> See [https://v4.xenomai.org/core/user-api/#device-ownership-and-access](https://v4.xenomai.org/core/user-api/#device-ownership-and-access)

Thanks.

I have created a xenomai group, added myself to the group, changed the ownership to `root:xenomai` of everything in `/dev/evl`, `/dev/evl` included, but still get `Permission denied`. I have checked my groups using id, xenomai is listed.

```
$ ls -la /dev/evl
total 0
drwxrwx--x  8 root xenomai    220 Aug 21 14:53 .
drwxr-xr-x 20 root root      3260 Aug 22 15:53 ..
drwxrwx--x  2 root xenomai     80 Aug 21 14:53 clock
crw-rw----  1 root xenomai 245, 0 Aug 21 14:54 control
drwxrwx--x  2 root xenomai     60 Aug 21 17:08 monitor
drwxrwx--x  2 root xenomai     60 Aug 21 14:53 observable
crw-rw----  1 root xenomai 245, 3 Aug 21 14:54 poll
drwxrwx--x  2 root xenomai     60 Aug 21 14:53 proxy
crw-rw----  1 root xenomai 245, 7 Aug 21 14:54 random
drwxrwx--x  2 root xenomai     60 Aug 22 16:02 thread
drwxrwx--x  2 root xenomai     60 Aug 21 14:53 xbuf
$ id -Gn
virgo wheel dialout ftp xenomai calcul softs_cc diaporama
```

It works though if I change the ownership of the `/dev/evl` tree to `pacaud:xenomai`. What would be the reason of this behaviour ?

Emmanuel.

Re: xenomai4 - running applications as regular user

[Philippe Gerum]

Emmanuel Pacaud <emmanuel.pacaud@lapp.in2p3.fr> writes:

> [1. text/markdown]
> Le vendredi 22 août 2025 à 09:13 +0200, Philippe Gerum a écrit :
>> 
>> > What is the recommended way to run out of band applications as regular user using xenomai4 ?
>> > 
>> > In xenomai3 documentation, there is a dedicated page about this, <[https://v3.xenomai.org/tips/regular-user/](https://v3.xenomai.org/tips/regular-user/)>, but I did not find similar instructions in xenomai4 version.
>> > 
>> > Emmanuel.
>> 
>> 
>> See [https://v4.xenomai.org/core/user-api/#device-ownership-and-access](https://v4.xenomai.org/core/user-api/#device-ownership-and-access)
>
> Thanks.
>
> I have created a xenomai group, added myself to the group, changed the ownership to `root:xenomai` of everything in `/dev/evl`, `/dev/evl` included, but still get `Permission denied`. I have checked my groups using id, xenomai is listed.
>
> ```
> $ ls -la /dev/evl
> total 0
> drwxrwx--x  8 root xenomai    220 Aug 21 14:53 .
> drwxr-xr-x 20 root root      3260 Aug 22 15:53 ..
> drwxrwx--x  2 root xenomai     80 Aug 21 14:53 clock
> crw-rw----  1 root xenomai 245, 0 Aug 21 14:54 control
> drwxrwx--x  2 root xenomai     60 Aug 21 17:08 monitor
> drwxrwx--x  2 root xenomai     60 Aug 21 14:53 observable
> crw-rw----  1 root xenomai 245, 3 Aug 21 14:54 poll
> drwxrwx--x  2 root xenomai     60 Aug 21 14:53 proxy
> crw-rw----  1 root xenomai 245, 7 Aug 21 14:54 random
> drwxrwx--x  2 root xenomai     60 Aug 22 16:02 thread
> drwxrwx--x  2 root xenomai     60 Aug 21 14:53 xbuf
> $ id -Gn
> virgo wheel dialout ftp xenomai calcul softs_cc diaporama
> ```
>
> It works though if I change the ownership of the `/dev/evl` tree to `pacaud:xenomai`. What would be the reason of this behaviour ?
>

In addition to making those files owned by the 'xenomai' group, you need
an udev rule fixing up the */clone files in each element directory
(clock, monitor etc.) giving rw permission to the group members too
(i.e. 0660).

-- 
Philippe.