USB redirect broken in virt-viewer

[d4g]

Issue description

USB redirect is brokoen in virt-viewer.

Listing of directory shows the issue:
/nix/store/rlkv757g7fmz05qfh1xpdg44zg2v2qfv-spice-gtk-0.34/bin/spice-client-glib-usb-acl-helper -> /run/wrappers/bin/spice-client-glib-usb-acl-helper /nix/store/rlkv757g7fmz05qfh1xpdg44zg2v2qfv-spice-gtk-0.34/bin/spice-client-glib-usb-acl-helper.real
The symlink shows to itself instead of spice-client-glib-usb-acl-helper.real

Steps to reproduce

• Open virt-viewer
• Connect to qemu/kvm/libvirt
• Try to redirect USB
• Read the error message

Technical details

NixOS details

• system: "x86_64-linux"
• host os: Linux 4.15.7, NixOS, 18.03pre130932.cc4677c36ee (Impala)
• multi-user?: yes
• sandbox: no
• version: nix-env (Nix) 2.0
• channels(root): "nixos-18.03pre130932.cc4677c36ee"
• nixpkgs: /nix/var/nix/profiles/per-user/root/channels/nixos/nixpkgs
• nix-channel: https://nixos.org/channels/nixos-unstable

Device details

• device: 20J6S0DM00 ThinkPad T470p
• cpu: Intel(R) Core(TM) i7-7700HQ CPU @ 2.80GHz
• gpu: Intel Corporation Device 591b (rev 04)

[d4g]

@fpletz

[xeji]

USB redirect requires a setuid wrapper (which cannot be included in the package), see #35214 .
Please activate this in configuration.nix as shown here: #35214 (review) and test again.

[xeji]

Anyway, this should fail with an appropriate message if the setuid wrapper doesn't exist.
@Mic92 has also suggested putting this into a nixos module.

[d4g]

It should not require a setuid wrapper, if the user is in the appropriate group and has read/write access to the devices.

If you read the error description, there is a problem with the symlink.
This was working on former versions of the package @xeji

[xeji]

I will look into it and fix the broken symlink.

[xeji]

Fixed in #37184. If you do not wish to use polkit authentication and the setuid wrapper, you can now build the package with withPolkit = false; and use custom udev rules instead. See comments in code of #37184.