EDIT: What is /run/udev/data/c241:1?

audetto · May 3, 2024, 6:32pm

I am creating a snap for a computer emulator built on SDL2.

audetto/AppleWin/blob/snapcraft/snap/snapcraft.yaml

name: applewin # you probably want to 'snapcraft register <name>'
base: core22 # the base snap is the execution environment for this snap
version: "1.30.18.10" # just for humans, typically '1.2+git' or '1.3.2'
summary: AppleWin Apple II emulator # 79 char long summary
description: |
  Apple II emulator for Linux

# grade: devel # must be 'stable' to release into candidate/stable channels
# confinement: devmode # use 'strict' once you have the right plugs and slots

grade: stable # must be 'stable' to release into candidate/stable channels
confinement: strict # use 'strict' once you have the right plugs and slots

parts:
  applewin-part:
    plugin: cmake
    source: .
    source-type: local
    # source-branch: snapcraft
    cmake-parameters:

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I get a strange error via snappy which I do not understand at all. Adding hardware-observe fixes it, but I am not sure what and why it is doing it.

Log: apparmor=“ALLOWED” operation=“open” class=“file” profile=“snap.applewin.applewin” name=“/run/udev/data/c241:1” pid=43202 comm=“sa2” requested_mask=“r” denied_mask=“r” fsuid=1000 ouid=0 File: /run/udev/data/c241:1 (read) Suggestions:

adjust program to use $SNAP_DATA
adjust program to use /run/shm/snap.$SNAP_NAME.*
adjust program to use /run/snap.$SNAP_NAME.*
adjust snap to use snap layouts (Snap layouts)
add ‘hardware-observe’ to ‘plugs’

Can anybody help?

aoyama · May 4, 2024, 3:38am

You can found those info about interface at snapd source code.

github.com

snapcore/snapd/blob/master/interfaces/builtin/hardware_observe.go

// -*- Mode: Go; indent-tabs-mode: t -*-

/*
 * Copyright (C) 2016 Canonical Ltd
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 3 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

package builtin

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That’s a lot of apparmor rules.

audetto · May 4, 2024, 7:43am

Thank you. I have figured out that this comes from network usage.

# Needed for udevadm
/run/udev/data/** r,
network netlink raw,

And if I disable networking, it does not trigger. I have added the network and network-bind plugs, but this is still not enough.

Moreover, is it possible to run my app normally (not as a snap, so I can debug it), while still triggering these warnings?

It would be a lot easier to see exactly which line causes the hardware-observe to be needed.

Regards

aoyama · May 4, 2024, 9:03am

Since those warnings are triggerd by apparmor, evevry snap pack’s apparmor file is stored in /var/lib/snapd/apparmor/profiles/

Maybe you can try write your own apparmor file from what snapd provided, and run you app normally.