Tio: Request for classic confinement

Please allow the tio snap to use classic confinement.

tio is a serial TTY I/O application that connects to serial devices in eg. /dev/serial/by-id/*

To do so classic confinement is required because snapcraft only supports allowing access to explicitly defined serial devices. This type of application is supposed to connect to any serial device.

In the future, it would be great if snapcraft could allow access to any serial type device via the serial-port plug.

The requirement for classic are understood. I believe that work may have started on dynamic slots for things like serial ports. @niemeyer, can you comment? Should we wait for that or proceed with vetting the publisher?

Any update on this issue?


Ping @niemeyer - can you comment?

I could really use that classic confinement approval - tio does not really work without it and I’m sure many users don’t know how to enable classic confinement.

Any chance to get approval for classic confinement for tio?


Please, anyone who want to chime in and let tio have classic confinement?


CC @pstolowski this looks like a nice case study for the hotplug work:

  • make tio classic (requires voting/vouching for the author)
  • while stable is classic and the hotplug work is not ready things stay as-is
  • as hotplug work reaches beta, work with the author on great hotplug experience and strict confinement
  • exercise various parts of the stack (hotplug, serial port interface, assumes: snapdXY, etc)
  • publish, release, announce, etc

Sounds like a good idea to me. I’ll be available to help out with the tio side of things and testing to improve the serial-port plug. tio simply needs to be allowed access to any device of the serial type (ie. all device nodes located in /dev/serial/*).

@niemeyer - can you comment on if this should wait on hotplug or be granted classic now?

@jdstrand For this case we should probably fix the interface instead. We support serial ports already. If it’s lacking, this sounds like a good chance to work with @lundmar on the details to make sure we can cover real world needs, and allow the snap to work strictly.

I would appreciate tio being granted classic confinement until the serial port plug supports connecting any serial port device. Unless of course, you guys think this is something which will be implemented very soon.

Please, can tio be granted classic confinement until the serial-port plug supports connections to arbitrary serial tty devices.

It’s been a month since my original request.


@reviewers can you take a look please?

Since the requirements are understood and the feature won’t be implemented before 2.35 (which is a number of weeks out) and @lundmar is known (lxi-tools), I think it is fine to proceed with vetting him for use of classic.

@popey, @Wimpress and/or @evan - can one of you do the vetting of the publisher and then I’ll grant use of classic?

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@popey, @Wimpress and/or @evan - ping

Things are moving very slowly - perhaps people are on summer vacation.

I am +1. @lundmar is upstream for Tio. The snap needs features not yet available in snapd before being strictly confined.

@evan - thank you for the vote, but have you vetted the publisher?

@jdstrand I have, and +1 from me too.