Glances won't start - Permission denied: '/usr/share/libdrm/amdgpu.ids'

[YamiYukiSenpai]

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Describe the bug
Glances won't start

To Reproduce
Steps to reproduce the behavior:

1. Start Glances with the following options '...'
2. Press the key '....'
3. See error

Expected behavior
The web version of glances runs.

I only noticed it because the Snap refreshed on my desktop. My server still has 4.4.1 from November so it wasn't refreshed

Screenshots
N/A

Environement (please complete the following information)

• Operating System (lsb_release -a or OS name/version):

> lsb_release -a
LSB Version:    n/a
Distributor ID: Garuda
Description:    Garuda Linux Broadwing
Release:        Soaring
Codename:       Broadwing

• Glances & psutil versions:

> glances -V
Glances version:        4.5.1_dev03
Glances API version:    4
PsUtil version:         7.1.1
Log file:               /tmp/glances-yamiyuki.log

• How do you install Glances (Pypi package, script, package manager, source): Snap
• Glances test:

> glances --issue
Traceback (most recent call last):
  File "/snap/glances/2660/bin/glances", line 6, in <module>
    sys.exit(main())
             ^^^^^^
  File "/snap/glances/2660/lib/python3.12/site-packages/glances/__init__.py", line 191, in main
    start(config=core.get_config(), args=core.get_args())
  File "/snap/glances/2660/lib/python3.12/site-packages/glances/__init__.py", line 150, in start
    mode = GlancesMode(config=config, args=args)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/snap/glances/2660/lib/python3.12/site-packages/glances/standalone.py", line 79, in __init__
    self.stats.update()
  File "/snap/glances/2660/lib/python3.12/site-packages/glances/stats.py", line 287, in update
    self.update_plugin(p)
  File "/snap/glances/2660/lib/python3.12/site-packages/glances/globals.py", line 575, in inner
    return _func(weakref.ref(self), *args, ttl_hash=_get_ttl_hash(ttl), **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/snap/glances/2660/lib/python3.12/site-packages/glances/globals.py", line 571, in _func
    return func(_self(), *args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/snap/glances/2660/lib/python3.12/site-packages/glances/stats.py", line 274, in update_plugin
    self._plugins[p].update()
  File "/snap/glances/2660/lib/python3.12/site-packages/glances/plugins/plugin/model.py", line 1162, in wrapper
    ret = fct(self, *args, **kw)
          ^^^^^^^^^^^^^^^^^^^^^^
  File "/snap/glances/2660/lib/python3.12/site-packages/glances/plugins/plugin/model.py", line 1179, in wrapper
    ret = fct(*args, **kw)
          ^^^^^^^^^^^^^^^^
  File "/snap/glances/2660/lib/python3.12/site-packages/glances/plugins/gpu/__init__.py", line 134, in update
    stats.extend(self.amd.get_device_stats())
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/snap/glances/2660/lib/python3.12/site-packages/glances/plugins/gpu/cards/amd.py", line 83, in get_device_stats
    device_stats['name'] = get_device_name(device)
                           ^^^^^^^^^^^^^^^^^^^^^^^
  File "/snap/glances/2660/lib/python3.12/site-packages/glances/plugins/gpu/cards/amd.py", line 127, in get_device_name
    amdgpu_ids = read_file(AMDGPU_IDS_FILE)
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/snap/glances/2660/lib/python3.12/site-packages/glances/plugins/gpu/cards/amd.py", line 111, in read_file
    with open(path) as f:
         ^^^^^^^^^^
PermissionError: [Errno 13] Permission denied: '/usr/share/libdrm/amdgpu.ids'

Additional context

> snap connections glances  
Interface                Plug                             Slot               Notes
docker                   glances:docker                   -                  -
hardware-observe         glances:hardware-observe         :hardware-observe  manual
home                     glances:home                     :home              -
log-observe              glances:log-observe              -                  -
mount-observe            glances:mount-observe            :mount-observe     manual
network                  glances:network                  :network           -
network-bind             glances:network-bind             :network-bind      -
network-observe          glances:network-observe          :network-observe   -
network-setup-observe    glances:network-setup-observe    -                  -
personal-files           glances:home-glances-config      :personal-files    -
physical-memory-observe  glances:physical-memory-observe  -                  -
power-control            glances:power-control            :power-control     manual
process-control          glances:process-control          :process-control   manual
raw-volume               glances:raw-volume               -                  -
removable-media          glances:removable-media          -                  -
system-files             glances:etc-glances-config       :system-files      -
system-observe           glances:proc-sys                 :system-observe    manual
system-observe           glances:system-observe           :system-observe    manual
uio                      glances:uio                      -                  -
upower-observe           glances:upower-observe           :upower-observe    -

You can also pastebin:

• the Glances configuration file (https://glances.readthedocs.io/en/latest/config.html#location)
• the Glances log file (https://glances.readthedocs.io/en/latest/config.html#logging)

[nicolargo]

Dammed, Snap is definitively a pain in the ass for me...

Analysis

The file /usr/share/libdrm/amdgpu.ids is used by the AMD GPU plugin to resolve the human-readable name of your GPU card (e.g. RX 6700 XT instead of the generic AMD GPU). Under Snap's strict confinement, access to host system files in /usr/share/ is blocked by default — which triggers the PermissionError.

Workaround

Until a fixed release is published, you can use the following workaround to connect the Snap to the host GPU resources manually:

sudo snap connect glances:opengl

Then restart Glances. This grants the Snap access to GPU-related host files, including /usr/share/libdrm/.

For the maintainer

This issue has two distinct root causes that should both be fixed.

Fix 1 — Python bug in glances/plugins/gpu/cards/amd.py (high priority)

The PermissionError exception is currently caught inside the with open() block, meaning it only guards f.read(). The actual exception under Snap strict confinement is raised at the open() call itself, so the except is never reached and the error propagates uncaught.

Current code (broken):

def read_file(*path_segments: str) -> str | None:
    path = os.path.join(*path_segments)
    if os.path.isfile(path):
        with open(path) as f:          # <-- PermissionError raised HERE
            try:
                return f.read().strip()
            except PermissionError:    # <-- never reached
                return None
    return None

Fixed code:

def read_file(*path_segments: str) -> str | None:
    """Return content of file or None if not accessible."""
    path = os.path.join(*path_segments)
    if os.path.isfile(path):
        try:
            with open(path) as f:
                return f.read().strip()
        except (PermissionError, OSError):
            # File exists but is not readable (e.g. Snap strict confinement)
            # Graceful degradation: caller will use a default value instead
            return None
    return None

Note: OSError is added as a broader catch to handle any similar OS-level access failures (e.g. broken device nodes), without changing the existing fallback behaviour — get_device_name() already returns 'AMD GPU' when the IDs file is unreadable.

This fix is non-breaking: it turns a hard crash into a silent graceful degradation, which is the expected behaviour in constrained environments.

Fix 2 — Snap configuration in snap/snapcraft.yaml (medium priority)

The opengl interface should be declared as a plug to give the Snap access to GPU-related host resources, including /usr/share/libdrm/. This is the standard interface used by Snap applications that interact with GPU hardware.

Add the opengl plug to the app definition:

apps:
  glances:
    plugs:
      - opengl            # grants access to GPU resources and libdrm host files
      - hardware-observe  # already present (keep it)
      # ... other existing plugs

The opengl interface is an auto-connected interface on the Snap Store — no manual store review required and no extra action needed from the user on standard Ubuntu Desktop installations.