Using udev tagging for snap interfaces

[adglkh]

It's a long-standing bug in snapd.
https://bugs.launchpad.net/snapd/+bug/1675738

We have some interfaces using udev tagging, but quite a few interfaces are still without udev tagging. So when people create a snap which has a combination of udev tagging plugs and none udev tagging plugs, an issue occurs due to device access denied since snap-confine only loads udev rules and creates a device cgroup for the tagged devices, excluding untagged ones.

[chipaca]

Please fix the unit tests

[jhodapp]

No need to update any of these copyright years. The year is supposed to indicate the first time this file was published publicly.

[codecov-io]

Codecov Report

Merging #3587 into master will decrease coverage by 0.01%.
The diff coverage is 77.19%.

@@            Coverage Diff             @@
##           master    #3587      +/-   ##
==========================================
- Coverage   74.98%   74.96%   -0.02%     
==========================================
  Files         382      382              
  Lines       33116    33408     +292     
==========================================
+ Hits        24831    25044     +213     
- Misses       6485     6564      +79     
  Partials     1800     1800

Impacted Files	Coverage Δ
interfaces/builtin/serial_port.go	66.07% <0%> (ø)	⬆️
interfaces/builtin/hidraw.go	65.76% <0%> (ø)	⬆️
interfaces/builtin/joystick.go	75% <100%> (+5%)	⬆️
interfaces/builtin/modem_manager.go	57.69% <100%> (+4.5%)	⬆️
interfaces/builtin/framebuffer.go	72.97% <100%> (+24.13%)	⬆️
interfaces/builtin/mir.go	71.79% <100%> (+5.12%)	⬆️
interfaces/builtin/time_control.go	72.97% <100%> (-0.72%)	⬇️
interfaces/builtin/bluez.go	72.09% <100%> (+4.52%)	⬆️
interfaces/builtin/pulseaudio.go	54.05% <100%> (+8.89%)	⬆️
interfaces/builtin/uhid.go	61.76% <100%> (-1.1%)	⬇️
... and 23 more

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[jdstrand]

@adglkh - I tried to help resolve the conflict in opengl_test.go but messed something up and when undoing it I made it so I could not recommit to the branch. Can you recommit your local changes to this branch to get it back to where it was? You can then grab opengl_test.go from https://github.com/jdstrand/snapd/tree/adglkh.udev_tagging.

Sorry for the trouble. :(

[jhodapp]

@jdstrand I'm curious why you closed this PR, was this intentional or by accident? I didn't see a reason for closing it.

[jdstrand]

@jhodapp - github did it as part of my mistake and I couldn't undo it. AIUI, when @adglkh recommits his changes to this PR, it will open again.

[jhodapp]

@jdstrand ok no problem, thanks for the explanation.

[adglkh]

@jdstrand It seems to me there's no way to re-open it even after I re-committed my changes.
A new PR can be found here #3617
Please take a look. Thanks.