Research 026 (the graphical session) and 027 (the system layer)

Evidence from both workstations and all four machines, read-only, and the
questions each must answer: seats and gating for the display stack, who starts
the session with which environment, contributions beyond shells, sway as a
sibling session; the container runtime with docker-compose on workstations
only, software outside the official repositories, secrets in the account's
environment, and three security findings.
This commit is contained in:
jochen
2026-10-04 11:17:34 +02:00
parent a8ffc2b94b
commit de032e704c
6 changed files with 569 additions and 0 deletions
@@ -0,0 +1,62 @@
---
status: active
initiated: 2026-10-04
touches:
- 02-DECISIONS/0176-the-login-shell-is-a-node-seat-and-execute-is-its-contract.md
- 02-DECISIONS/0177-a-unit-may-be-user-scoped-and-the-service-manager-is-a-node-seat.md
- 02-DECISIONS/0182-inside-a-home-the-mesh-owns-what-it-places-and-holds-the-rest-as-found.md
- 02-DECISIONS/0203-the-accounts-environment-is-one-modules-and-every-module-contributes-to-it.md
- 02-DECISIONS/0204-a-module-contributes-shell-code-to-the-login-shell-in-named-slots.md
- 02-DECISIONS/0205-software-the-distribution-does-not-package-ships-as-a-pinned-archive-of-the-module.md
- 03-DESIGN/01-to-be/37-the-operators-machine.md
- 03-DESIGN/01-to-be/38-building-the-operators-machine.md
- 04-ISSUES/168-a-setting-reaches-every-file-and-contribution/00-report.md
became: []
---
# 026 — The graphical session as modules
## What is investigated
The workstations' graphical session as modules of the mesh, at the same level as the shell
([to-be 41](../../03-DESIGN/01-to-be/41-the-shell-and-the-accounts-environment.md)): a package, files
under the account's home, a seat, and nothing that names a machine. The pieces are:
- the login manager;
- how a session starts and what environment it gets;
- the display server (X today, Wayland as a sibling);
- the window manager (i3, and sway as its Wayland sibling);
- the terminal emulator (xterm);
- the session's companions: bar, compositor, launcher, notifier, lock and idle, clipboard,
wallpaper, theming, fonts.
[To-be 38](../../03-DESIGN/01-to-be/38-building-the-operators-machine.md) names this WP7, and says
each seat begins with a record naming its holders and verbs. [To-be 37](../../03-DESIGN/01-to-be/37-the-operators-machine.md)
§4 leaves one question for the resolver: whether a held seat can gate another's assignment.
## Why
The operator asked for the graphical modules next, at the shell's level, and for one consistent
experience across machines. Since the predecessor retired, nothing manages the workstations'
desktops. Measured in [01](01-what-the-workstations-run.md):
- Two workstations carry one 983-line predecessor module's output, still byte-identical in its core.
- One workstation also carries another machine's hardware fragments.
- One runs a session that predates two fixes, with two notification daemons and two portals.
- The session's environment is a hand-kept second copy of the account's, beside the one the mesh
now writes.
## What it touches
- **The seat table:** up to ten node seats.
- **The resolver:** a seat held on a node gating another module's assignment.
- **The contribution mechanism of ADR 0204:** whether it generalises beyond shells, or whether
tools' own drop-in directories serve.
- **The host's user-scoped units** (mesh-host #72, still open).
- **Settings** for per-machine values (issue 168).
- **ADR 0205's archive** for the two pieces the distribution does not package.
## Documents
- [01 — What the workstations run](01-what-the-workstations-run.md): evidence.
- [02 — The questions and the options](02-the-questions-and-the-options.md)
@@ -0,0 +1,141 @@
# 01 — What the workstations run
Measured 2026-10-04 on the two workstations of one installation, read-only: a laptop with a hybrid
GPU and an internal panel, and a desktop with one GPU and two external monitors. Both run the same
predecessor-generated desktop. File equality was checked by checksum across the two machines.
## How a session starts
The chain is the same on both:
1. The login manager (`lemurs`, built from the distribution's user repository, its package now in
the official one) runs its X setup script on a virtual terminal.
2. That script sources the login shell's profile files, then `~/.xprofile`, then the system's
`xinitrc.d` drop-ins, then merges `~/.Xresources`.
3. `~/.xprofile` reuses the systemd user manager's bus, then sources `~/.xinitrc`.
4. `~/.xinitrc` sets up the session and ends with `exec i3`.
The login manager's own window-manager entry (`exec startx`) is never reached. Its configuration
file uses a format two releases old, and an unmerged newer one sits beside it.
**What `~/.xinitrc` does**, in order:
1. Sources the system drop-ins, which import `DISPLAY` and `XAUTHORITY` into the user manager.
2. Starts the keyring and exports its ssh socket.
3. Exports the session's environment:
- `PATH`, with nine entries, one of them a directory that no longer exists;
- toolchain variables;
- `XDG_CONFIG_HOME` and `XDG_DATA_DIRS` (with flatpak);
- five GTK/Qt theme variables;
- the desktop's identity (`XDG_CURRENT_DESKTOP`, `XDG_SESSION_DESKTOP`);
- three of the operator's own variables.
4. Imports an explicit allowlist of ten of those into the user manager and D-Bus activation. It is
never `--all`, because:
5. a predecessor file of **secrets as environment variables** (package-registry and API tokens) is
sourced next.
6. Sets the screensaver and display power timeouts, restores the wallpaper, and starts the lock
watcher in a respawn loop. It is deliberately not a unit, because it needs the login session.
7. `exec i3`.
**The account's environment, as of today, has three sources that disagree:**
- this file, for the session;
- the mesh's `environment.sh`, for shells
([ADR 0203](../../02-DECISIONS/0203-the-accounts-environment-is-one-modules-and-every-module-contributes-to-it.md));
- `~/.config/environment.d/`, for the user manager. It holds the mesh's `50-mesh.conf`, and a
predecessor file that **sets `PATH` outright** and sorts after it.
## The roles, and what fills them
| role | software | where configured |
|---|---|---|
| login manager | lemurs | `/etc/lemurs/*` (identical on both, and to the predecessor's source) |
| session start and environment | the login manager's X setup, `~/.xprofile`, `~/.xinitrc`, `xinitrc.d`, the D-Bus import, `environment.d` | `~/.xprofile`, `~/.xinitrc`, `~/.config/environment.d/*` |
| display server | Xorg (`xorg-server`, `xinit`, the X apps; vendor drivers per GPU) | **no** `xorg.conf.d`; monitors by `xrandr` scripts |
| monitor layout | `xrandr` scripts (arandr), a hotplug rule on the laptop | `~/.screenlayout/`, a scripts folder, a window-manager fragment |
| window manager | i3 4.25 | `~/.config/i3/config` and `config.d/*`, a reload watcher (user unit) |
| bar | i3bar with i3status-rust | `~/.config/i3status-rust/*`, 14 themes, a bar watchdog (user unit) |
| terminal | xterm (the only terminal installed) | `~/.Xresources.d/xterm`, the window manager's binding, the compositor's opacity rule |
| compositor | picom | `~/.config/picom/picom.conf` |
| launcher and menus | rofi | `~/.config/rofi/*`, launcher, power-menu and theme-picker scripts |
| notifier | dunst (D-Bus activated) | `~/.config/dunst/dunstrc`, `dunstrc.d/*` |
| lock, idle, display power | xss-lock and i3lock-color, `xset` | `~/.xinitrc`, a lock script |
| clipboard | greenclip, xclip | `greenclip.toml` |
| wallpaper | feh | `~/.fehbg` (points into the predecessor's tree) |
| theming | Adwaita dark, qt5ct/qt6ct, the desktop portal (GTK backend pinned) | GTK `settings.ini`, `qt*ct.conf`, `portals.conf`, an appearance script, `.Xresources` cursor |
| fonts | Hack and Meslo Nerd fonts in `~/.local/share/fonts` (not packaged), noto | `~/.Xresources.d/xft` (DPI fixed at 96) |
| keyboard | nothing set; the default layout; vendor keys via triggerhappy on the laptop | window-manager bindings, `/etc/triggerhappy` |
**Packages:** every piece except two is in the distribution's official repositories, and the login
manager now is too. The two exceptions are the lock screen's colour build (`i3lock-color`) and the
clipboard manager (`rofi-greenclip`). The Nerd fonts exist as official packages, but both machines
carry hand-copied files instead.
## Identical, different, and why
**Byte-identical on both machines:**
- the session files: `.xinitrc`, `.xprofile`, `.Xresources` and its drop-ins;
- the i3 main configuration and two of its fragments;
- the bar's top configuration and themes;
- picom, rofi, the GTK and Qt settings, the portal configuration, the login manager.
**Different, by cause:**
| cause | what |
|---|---|
| hardware | the monitor layout script; the bar's battery block; the laptop's power and vendor-key units and udev rules |
| misassignment | the desktop carries the **laptop's** hardware fragments: the vendor-key daemon and its triggers, the backlight rule, the brightness drop-in, a touchpad reset, and the laptop's monitor layouts, in an older version |
| drift | the notifier's position and corner radius; a "temporary" window-manager fragment from a test; the bar watchdog disabled; a second Qt configuration tool; different font builds |
| a stale session | the desktop's session began before two fixes, so it runs two notification daemons and two portals, and its user manager lacks the desktop's identity |
**Dead references:** the window manager starts a polkit agent that is installed on neither machine,
so there is no polkit agent at all. `PATH` names a directory that does not exist.
**Per-machine values inside shared files:**
- the DPI;
- absolute home paths, in the clipboard configuration and the flatpak data directories;
- the laptop's panel name, inside a fragment both machines carry.
## User units the desktop needs
| unit | does | laptop | desktop |
|---|---|---|---|
| reload watcher | reloads the window manager and bar when their files change | on | on |
| bar watchdog | restarts a dead bar | on | off |
| clipboard daemon | from its package | via the window manager | unit **and** window manager |
| vendor power profile, memory guard | laptop power | on | — |
None is managed. Applying them as the account needs the host's user scope
([ADR 0177](../../02-DECISIONS/0177-a-unit-may-be-user-scoped-and-the-service-manager-is-a-node-seat.md)),
which is still an open change.
## The predecessor's module
One manifest of 983 lines covers the window manager, bar, launcher, notifier, compositor, lock
screen, session bootstrap, theming and scripts. It:
- has four *flavors*: i3, laptop (i3 plus the monitor wizard and hotplug), desktop (i3 plus
nothing) and a laptop model (laptop plus vendor keys);
- has about **105 theme variables** substituted into templates: border, gaps, fonts, workspace
names, every colour of bar, launcher, notifier and lock screen, compositor opacity, cursor, idle
times, Qt and GTK theme names;
- enables the two user units from an install hook.
Separate modules held the login manager and the display server (one flavor, `xorg`, with a comment
calling `wayland` "the intended sibling"). The shell module held no graphical part.
## Wayland and sway
**Nothing exists.** There is no compositor, no sway configuration, no Wayland session entry, and the
login manager's Wayland directory is empty. What is installed is libraries:
- Wayland itself and the Qt Wayland plugins, which other packages pull in;
- `xwayland`, explicitly installed and required by nothing;
- on the desktop, an orphaned compositor library from another desktop environment, and that
environment's portal backend, pulled in by a game launcher. The portal configuration pins
against it.
Every piece a sway session needs is in the official repositories: the compositor, its lock screen,
a terminal (`foot`), a bar (`waybar`), a notifier (`mako`) and `xwayland`.
@@ -0,0 +1,123 @@
# 02 — The questions and the options
Seven questions. Each has its options and a starting position, which is what this effort tests, not
what it has decided.
## 1. How finely the desktop splits into modules
| | option | for | against |
|---|---|---|---|
| G1 | One desktop module, as the predecessor had | one assignment | flavors again, per machine; ADR 0174 refuses them, and the evidence shows a flavor landing on the wrong machine |
| G2 | **One module per piece of software:** `lemurs`, `xorg`, `i3`, `i3status-rust`, `xterm`, `picom`, `rofi`, `dunst`, `xss-lock` with the lock screen, `greenclip`, `feh`, a theme module, a fonts module | each is what it declares; a machine gets exactly what is assigned; the same split already works for the shell and its plugins | about thirteen assignments per workstation |
| G3 | G2, plus a named **set** the controller assigns as one (for example *the X desktop*) | G2's precision with G1's convenience | a set is a new controller concept |
**Starting position: G2.** Whether a set is worth a record is left until the thirteen assignments
have been done by hand once.
## 2. The seats
Research 018 listed the candidates. ADR 0204 has since put the login shell in the mesh's own set,
because a role with a protocol should not depend on one module's registration. The same reasoning
applies here:
| seat | holders | protocol, first verbs |
|---|---|---|
| `node-login-manager` | lemurs, greetd | which sessions it offers, the default session |
| `node-display-server` | xorg, sway | `displays`, `layout` |
| `node-display-session` | i3, sway | `reload`, `workspaces`, `windows` |
| `node-terminal-emulator` | xterm, foot, alacritty | which terminal `$TERMINAL` names; `open` |
| `node-bar`, `node-compositor`, `node-launcher`, `node-notifier`, `node-lock-screen`, `node-clipboard` | the pieces above, and their Wayland counterparts | one verb or none each, until a use asks for one |
**A compositor that is its own server holds two seats.** Sway is both the display server and the
display session. A module may claim several seats, so this needs nothing new.
**Starting position:** the first four seats are in the mesh's own set. The companion seats are
added only as each holder is written; for those, a module without a seat is acceptable at first.
## 3. One module requiring another seat to be held
i3 needs an X server held on its node, and sway needs nothing below it. A terminal needs a session.
To-be 37 left open how that is said.
| | option | for | against |
|---|---|---|---|
| R1 | A seat **delivers a provision** (`x11-display`, `wayland-display`) and a module requires it at node scope. The seat table has a `delivers` field already, and requirements already resolve | existing machinery; the refusal names the seat and its possible holders, which design 27 already lists | a node-scoped requirement that never crosses machines has to be stated as such |
| R2 | A new field, *needs the seat X held* | reads plainly | a second way to say what R1 says |
| R3 | Nothing; assign carefully | — | the mistake the evidence shows (a laptop's fragments on a desktop) is exactly an unchecked assignment |
**Starting position: R1.** `xorg` and `sway` each deliver what they serve. `i3`, `picom` and `xss-lock`
require `x11-display`. `foot` requires a Wayland display, and xterm requires an X one, which a Wayland
session gives through `xwayland`.
## 4. Who starts the session, and with what environment
Today `~/.xinitrc` is a hand-kept second environment and the session's whole start script.
| | option | for | against |
|---|---|---|---|
| S1 | The display server's module writes `~/.xinitrc` **into**: a mesh block at the start that sources the account's environment (`environment.sh`), merges the X resources, and runs the session's contributed start lines. The session holder's module contributes its `exec` line. The operator's lines stay after the block | one environment for shells, the session and the user manager; nothing to keep in step | the order inside `.xinitrc` becomes the slot order of a contribution (question 5) |
| S2 | The login manager's module owns the session script under `/etc` | system scope; no home file | the environment is the account's, and the script is the same for every account |
| S3 | Leave `.xinitrc` the operator's | nothing to build | the third environment stays |
**Starting position: S1.**
- The desktop's identity (`XDG_CURRENT_DESKTOP`) and the theme variables become **environment
contributions** (ADR 0203) from `i3` and from the theme module. They then also reach the user
manager through `environment.d`, which replaces most of today's allowlist import.
- The secrets file stays out of the environment until research 027 settles how a secret reaches an
account.
## 5. How other modules contribute to a holder's file
The terminal's settings are X resources. A bar, a launcher binding and a hardware module's key
bindings are window-manager configuration. Autostarts are the session's. ADR 0204 built slot
contributions for shells only.
| | option | for | against |
|---|---|---|---|
| C1 | **The tool's own drop-in directory**, where it has one: i3's `include`, dunst's `dunstrc.d`, X resources' `#include`, XDG autostart entries, `environment.d`. Each contributor owns its own file there | no mesh change; the tools already read these directories; unassigning removes the file | each contributor names a path in another tool's directory (ADR 0204 rejected this for shells, where no drop-in convention exists); ordering is by file name |
| C2 | **ADR 0204's mechanism generalised:** `contributes` text *for a format* (`zsh`, `xresources`, `i3`, `xinitrc`) in a slot, placed by the holder's placeholder | one mechanism, checked by the controller, order declared | every format must be named in the controller; a bigger change to ADR 0204 |
| C3 | C1 where the tool has a drop-in convention, C2 where it does not (`.xinitrc`, `.Xresources` order) | uses each tool's own grain | two mechanisms to learn |
**Starting position: C3**, with the boundary drawn by the tools. A tool that reads a directory gets
drop-ins. A file without one gets slots. This means amending ADR 0204's "shell" to "a format", which
is a progressive extension rather than a reversal.
## 6. What varies per machine
| what | today | option |
|---|---|---|
| monitor layout | per-machine `xrandr` scripts, monitor names baked in | a **setting** of `xorg` (issue 168), and a `layout` verb of the display server seat |
| DPI, fonts' size | fixed in an X resource | a setting |
| battery block, vendor keys, brightness, touchpad | a laptop model's flavor | **a hardware module** per machine model, contributing its window-manager fragment, bar block and udev rules. The desktop simply is not assigned it |
| theme (the 105 variables) | template substitution | settings of each tool's module, after issue 168 closes (ADR 0174). Until then each module carries today's values as its default |
**Starting position:**
- Hardware modules for what follows the machine.
- Defaults now, settings after issue 168, for what the operator varies.
- The monitor layout waits for settings. Until then it is an operator-owned script the display
server's block calls if present.
## 7. Wayland and sway
Nothing of a Wayland session exists, and every piece is officially packaged. "Wayland" is a protocol,
not a piece of software, so it has no module of its own. Its parts are `sway` (server and session),
`swaylock`, `foot`, `waybar`, `mako`, and `xwayland` for X clients.
**Starting position:**
- The seats and the requirements (questions 2 and 3) are designed so that sway fits from the first
day.
- The X stack is built first, because it is what runs.
- `sway` and its companions are written after that, and proven on one workstation as a second
session the login manager offers beside i3. That lets the operator try it without losing the
working desktop.
## Prerequisites this effort cannot remove
- **User-scoped units** (mesh-host #72) for the reload watcher and the bar watchdog.
- **Settings** (issue 168) for monitors and theme values.
- **The two packages not in the official repositories:** the lock screen's colour build and the
clipboard manager. Each is ADR 0205's case, a pinned archive, or a choice of an official
alternative (`i3lock` without colours; `clipmenu`/`cliphist`).