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vasilito b66807c33e docs: remaining v3.0 → v4.0 references in subsystem plans

GREETER-LOGIN, DBUS-INTEGRATION, BOOT-PROCESS-IMPROVEMENT
all now reference CONSOLE-TO-KDE v4.0

2026-05-01 02:01:28 +01:00

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Red Bear OS D-Bus Integration Plan

Implementation status (2026-04-29): All DBUS plan code artifacts are build-verified. Remaining items are runtime validation gates requiring QEMU.

Version: 3.0 — 2026-04-29 Status: Active plan aligned with the desktop path v4.0 Scope: Full D-Bus infrastructure for KDE Plasma 6 on Wayland, tightly integrated with Redox scheme IPC Parent plan: local/docs/CONSOLE-TO-KDE-DESKTOP-PLAN.md (v4.0)

1. Executive Summary

D-Bus is mandatory infrastructure for KDE Plasma 6 — not optional, not deferrable. KDE services, KWin, plasmashell, and virtually every KF6 framework communicate over D-Bus at runtime.

Red Bear OS already has D-Bus 1.16.2 building with a 24-line redox.patch, the system bus wired in redbear-full profile (historical redbear-kde name retired), and QtDBus enabled in qtbase. This is a solid foundation, but it is only the transport layer. What's missing is the service layer — the D-Bus services that KDE actually expects to talk to.

This plan defines a Redox-native D-Bus service architecture built on three decisions:

Use dbus-daemon (reference implementation), not dbus-broker. It works without systemd, supports traditional .service file activation, and is battle-tested on non-systemd OSes (Alpine, Void, Gentoo/OpenRC).
Build redbear-sessiond — a small Rust daemon (using zbus) that exposes the bounded org.freedesktop.login1 surface KWin already expects, plus a few higher-level manager helpers (GetUser, ActivateSessionOnSeat, lock/unlock/terminate helpers) that broader KDE session plumbing can call without forcing Red Bear into an elogind-sized reimplementation. Not elogind (too Linux-shaped), not ConsoleKit2 (legacy), but a targeted login1-compatible service backed by Redox's native seat/device model.
Keep schemes and D-Bus separate. Schemes are the native resource plane. D-Bus is the desktop compatibility plane. Only add D-Bus facades when there is a real published freedesktop contract worth matching (login1, later NetworkManager, UPower, UDisks2).

Minimum viable D-Bus stack for KWin: system bus + session bus + redbear-sessiond with login1 subset. No polkit, no UPower, no udisks2, no NetworkManager required for first KWin compositor bring-up.

2. Architecture Principles

2.1 Schemes = Native Resource Plane, D-Bus = Desktop Compatibility Plane

┌─────────────────────────────────────────────────────────────────────┐
│  KDE Plasma / KWin / KF6                                           │
│  (speaks D-Bus, expects freedesktop contracts)                     │
├─────────────────────────────────────────────────────────────────────┤
│  D-Bus Compatibility Services                                      │
│  redbear-sessiond (login1)   redbear-notifications   redbear-polkit│
│  (zbus-based Rust daemons, translating D-Bus ↔ scheme calls)      │
├─────────────────────────────────────────────────────────────────────┤
│  dbus-daemon (system bus + session bus)                            │
│  Classic .service activation, XML policies                         │
├─────────────────────────────────────────────────────────────────────┤
│  Redox Schemes (native IPC)                                        │
│  scheme:pci  scheme:input  scheme:drm  scheme:net  scheme:acpi    │
│  evdevd       udev-shim     redox-drm   netd        acpid         │
└─────────────────────────────────────────────────────────────────────┘

D-Bus services wrap scheme resources into freedesktop-compatible contracts. They do not replace or mirror schemes. Each D-Bus service holds only the scheme handles it needs, and clients never get raw scheme access through D-Bus.

2.2 Use Existing Contracts, Don't Invent New Ones

Namespace	Use For
`org.freedesktop.login1`	Session/seat/device tracking — KWin expects this
`org.freedesktop.Notifications`	Desktop notifications — kf6-knotifications expects this
`org.freedesktop.NetworkManager`	Deferred — not in current Red Bear OS scope
`org.freedesktop.UPower`	Power management — PowerDevil expects this
`org.freedesktop.UDisks2`	Storage management — Solid/udisks backend expects this
`org.freedesktop.PolicyKit1`	Privileged actions — KAuth expects this
`org.kde.*`	KDE-specific services — KWin, plasmashell, kglobalaccel, kded6
`org.redbear.*`	Red Bear-specific services that don't match any freedesktop contract

2.3 No Generic Scheme→D-Bus Bridge

Do NOT build a universal translator that mirrors every scheme as a D-Bus object. Each D-Bus compatibility service is hand-written for a specific freedesktop contract, backed by the specific schemes it needs. This keeps the architecture honest and avoids a leaky abstraction.

2.4 Rust-Native for New Services, C for Existing Daemons

Component	Implementation	Why
`dbus-daemon`	C (freedesktop upstream)	Battle-tested, minimal redox.patch, no reason to rewrite
`libdbus-1`	C (part of dbus package)	Required by QtDBus, kf6-kdbusaddons
`redbear-sessiond`	Rust + `zbus`	New code, Rust-native OS, async, strong typing
Future compat daemons	Rust + `zbus`	Same reasons as redbear-sessiond
KDE apps (KWin, plasmashell)	C++ via QtDBus	Upstream KDE code, not our concern

3. Current State Assessment

3.1 What Exists and Works

Component	Location	Status	Detail
D-Bus 1.16.2 daemon	`recipes/wip/services/dbus/`	✅ Builds, bounded runtime	24-line redox.patch (epoll guard + socketpair fix), meson build with systemd disabled
libdbus-1	Part of dbus package	✅ Builds	`libdbus-1.so.3.38.3` staged, pkgconfig and cmake files present
QtDBus	`recipes/wip/qt/qtbase/`	✅ Enabled	`FEATURE_dbus=ON` for target build, Qt6DBus module present
kf6-kdbusaddons	`local/recipes/kde/kf6-kdbusaddons/`	✅ Builds	KF6 D-Bus convenience wrappers, provides qdbus tool integration
D-Bus system bus	`config/redbear-full.toml`	✅ Wired	`12_dbus.service` launches `dbus-daemon --system`, `messagebus` user (uid=100), `/var/lib/dbus` + `/run/dbus` directories
D-Bus session bus	`local/recipes/system/redbear-greeter/source/redbear-kde-session`	✅ Scripted	`redbear-kde-session` launches `dbus-launch --sh-syntax` before KWin
seatd	`config/redbear-full.toml`	✅ Wired	`13_seatd.service`, `LIBSEAT_BACKEND=seatd`, `SEATD_SOCK=/run/seatd.sock`
kf6-kservice	`local/recipes/kde/kf6-kservice/`	✅ Builds	Depends on kf6-kdbusaddons
kf6-kglobalaccel	`local/recipes/kde/kf6-kglobalaccel/`	✅ Builds	Depends on kf6-kdbusaddons
Session activation scaffolds	`local/recipes/system/redbear-dbus-services/`	✅ Staged	Session `.service` files now cover kded6, kglobalaccel, ActivityManager, JobViewServer, ksmserver, notifications, and StatusNotifierWatcher
KWin (D-Bus)	`local/recipes/kde/kwin/`	✅ USE_DBUS=ON	Registers `org.kde.KWin` on session bus

3.2 What Exists But Is Incomplete

Component	Location	Status	Gap
elogind	`recipes/wip/services/elogind/`	⚠️ Recipe only	"not compiled or tested" — needs libeudev + libcap, too Linux-shaped for Redox
kf6-knotifications	`local/recipes/kde/kf6-knotifications/`	⚠️ D-Bus ON (scaffold-backed)	Built with `-DUSE_DBUS=ON`, but current notification daemon is still a minimal scaffold
kf6-kio	`local/recipes/kde/kf6-kio/`	⚠️ D-Bus OFF	Built with `-DUSE_DBUS=OFF` — D-Bus IPC disabled, has systemd1 XML interfaces in source
kf6-solid	`local/recipes/kde/kf6-solid/`	⚠️ D-Bus OFF	Built with `-DUSE_DBUS=OFF` — UDev/UPower/udisks2 backends all disabled
kf6-kwallet	`local/recipes/kde/kf6-kwallet/`	⚠️ Not in enabled subset	Real API-only cmake build (no daemon); exists in-tree, not part of current redbear-full
plasma-workspace	`local/recipes/kde/plasma-workspace/`	⚠️ Partial	Explicit dbus dep; sub-services activation files staged; runtime proof requires QEMU

3.3 What Ships Today (Scaffolds and Deferred Items)

Component	Namespace	Purpose	KDE Consumer
Session tracker	`org.freedesktop.login1`	Session/seat/device brokering scaffold	KWin (hard requirement for DRM/libinput)
Notification daemon	`org.freedesktop.Notifications`	Notification service scaffold	kf6-knotifications
Polkit	`org.freedesktop.PolicyKit1`	Authorization scaffold (always-permit)	KAuth
UPower	`org.freedesktop.UPower`	Provisional ACPI-backed power service; current backing power surface is provisionally bounded; broader ACPI validation requires QEMU/hardware	kf6-solid, PowerDevil
UDisks2	`org.freedesktop.UDisks2`	Bounded real `disk.*` / partition enumeration	kf6-solid
D-Bus service files	`/usr/share/dbus-1/`	Activation is staged and shipped for the current scaffold services plus bounded KDE session daemons (`kded6`, `kglobalaccel`, ActivityManager, JobViewServer, ksmserver)	All D-Bus services
D-Bus policy files	`/etc/dbus-1/`	Policy is staged and shipped for the current scaffold services	All D-Bus services
zbus crate marker	`local/recipes/libs/zbus/`	Build-ordering marker; actual zbus crate is fetched by downstream Cargo builds	Future Rust D-Bus services

Deferred and not shipped in the current implementation cycle:

org.freedesktop.NetworkManager / redbear-nm — Red Bear OS uses redbear-netctl for now

4. Gap Analysis

4.1 Critical Path Gaps (blocks KWin compositor)

KWin needs:
  dbus-daemon --system          ✅ exists, wired
  dbus-daemon --session         ✅ exists, wired in redbear-kde-session
  org.freedesktop.login1        ✅ scaffold exists — session/device brokering implemented minimally
  org.kde.KWin (self-register)  ✅ KWin does this itself (dbusinterface.cpp)

The single critical runtime-risk area is org.freedesktop.login1. KWin's session_logind.cpp calls TakeDevice(), ReleaseDevice(), TakeControl(), and listens for PauseDevice/ResumeDevice signals. Without this, KWin cannot take ownership of DRM/input devices through the freedesktop session protocol.

KWin's session selection chain is: logind → ConsoleKit → Noop. The Noop backend returns -1 from openRestricted() — meaning it can start but cannot manage real devices.

4.2 Desktop Session Gaps (blocks plasma-workspace)

plasma-workspace needs:
  org.kde.KWin                    ✅ KWin provides
  org.kde.kglobalaccel            ⚠️ activation file staged — daemon/runtime proof build-verified; QEMU validation supplementary
  org.kde.kded6                   ⚠️ activation file staged — daemon/runtime proof build-verified; QEMU validation supplementary
  org.kde.plasmashell             ✅ plasmashell provides (self-register)
  org.kde.osdService              ✅ plasmashell provides
  org.freedesktop.Notifications   ✅ scaffold exists — current daemon logs to stderr only

4.3 Full Desktop Gaps (blocks complete KDE Plasma)

Complete Plasma needs (after re-enabling disabled components):
  org.freedesktop.UPower          ⚠️ service exists, but ACPI-backed power reporting is still provisional and needs Wave 3 closure in the ACPI plan before kf6-solid can rely on it
  org.freedesktop.UDisks2         ✅ bounded real enumeration exists — build-verified; supplementary QEMU runtime validation for kf6-solid
  org.freedesktop.NetworkManager  ⏸️ DEFERRED — Red Bear OS uses redbear-netctl for now
  org.freedesktop.PolicyKit1      ⚠️ scaffold exists — KAuth still blocked on missing PolkitQt6-1 packaging
  org.freedesktop.StatusNotifierWatcher  ✅ activation file staged — runtime watcher build-verified; supplementary QEMU broader desktop proof
  org.kde.JobViewServer           ⚠️ activation file staged — kuiserver binary/runtime still open
  org.kde.ksmserver               ⚠️ activation file staged — session manager binary/runtime still open
  org.kde.ActivityManager         ⚠️ activation file staged — activity manager binary/runtime still open
  org.freedesktop.ScreenSaver: deferred (not on critical path) — screen locking

4.4 Build System Gaps

Gap	Detail
`zbus` recipe is only a marker	Build-ordering marker exists; actual Rust crate comes from downstream Cargo resolution
D-Bus service activation is scaffolded	`/usr/share/dbus-1/system-services/` and `session-services/` are staged for current services
D-Bus policy configuration is scaffolded	`/etc/dbus-1/system.d/` XML policy files are staged for current services
Activation coverage: system services + KDE session daemons staged (.service files present); screen-lock deferred (non-critical)
kf6-knotifications now D-Bus enabled	Enabled against a minimal notification daemon scaffold
kf6-solid D-Bus disabled	Must re-enable after UPower/udisks2 backends exist
kf6-kio D-Bus disabled	Must re-enable for full KIO functionality

5. Architecture Design

5.1 Overall Stack

┌──────────────────────────────────────────────────────────────────────────┐
│                     KDE Plasma 6 Desktop Session                        │
│   plasmashell, kwin_wayland, kded6, kglobalaccel, plasma applets        │
├──────────────────────────────────────────────────────────────────────────┤
│                     Session Bus (per-user)                               │
│   Started by: redbear-kde-session via dbus-launch or dbus-run-session   │
│   Policy: /etc/dbus-1/session.conf                                      │
│   Services: /usr/share/dbus-1/session-services/                         │
│   ┌──────────────────────────────────────────────────────────────────┐  │
│   │  org.kde.KWin           (KWin self-registers)                   │  │
│   │  org.kde.plasmashell    (plasmashell self-registers)            │  │
│   │  org.kde.kglobalaccel   (kglobalaccel daemon)                   │  │
│   │  org.kde.kded6          (KDE daemon)                            │  │
│   │  org.kde.ActivityManager (kactivitymanagerd scaffold)           │  │
│   │  org.kde.JobViewServer  (kuiserver scaffold)                    │  │
│   │  org.kde.ksmserver      (ksmserver scaffold)                    │  │
│   │  org.freedesktop.Notifications  (redbear-notifications)         │  │
│   │  org.freedesktop.StatusNotifierWatcher  (redbear-statusnotifier)│  │
│   └──────────────────────────────────────────────────────────────────┘  │
├──────────────────────────────────────────────────────────────────────────┤
│                     System Bus (machine-global)                          │
│   Started by: Redox init (12_dbus.service)                              │
│   Policy: /etc/dbus-1/system.conf + system.d/*.conf                     │
│   Services: /usr/share/dbus-1/system-services/                          │
│   ┌──────────────────────────────────────────────────────────────────┐  │
│   │  org.freedesktop.login1   (redbear-sessiond)                    │  │
│   │  org.freedesktop.DBus     (dbus-daemon itself)                  │  │
│   │  [Phase 4+] org.freedesktop.UPower       (redbear-upower)       │  │
│   │  [Phase 4+] org.freedesktop.UDisks2      (redbear-udisks)       │  │
│   │  [deferred] org.freedesktop.NetworkManager  (not in scope)      │  │
│   │  [Phase 4+] org.freedesktop.PolicyKit1   (redbear-polkit)       │  │
│   └──────────────────────────────────────────────────────────────────┘  │
├──────────────────────────────────────────────────────────────────────────┤
│                     dbus-daemon 1.16.2                                   │
│   C reference implementation, redox.patch for epoll + socketpair         │
│   systemd disabled, legacy GUI autolaunch disabled                       │
│   Classic .service file activation                                       │
├──────────────────────────────────────────────────────────────────────────┤
│                     Redox Schemes (native IPC)                           │
│   scheme:input → evdevd → /dev/input/eventX                             │
│   scheme:drm → redox-drm → DRM/KMS                                      │
│   scheme:pci → pcid-spawner → PCI device access                         │
│   scheme:net → netd → network interfaces                                │
│   scheme:firmware → firmware-loader → GPU blobs                         │
│   scheme:acpi → acpid → ACPI/DMI data                                   │
│   scheme:seat → seatd → seat management (libseat API)                   │
└──────────────────────────────────────────────────────────────────────────┘

5.2 D-Bus Service Lifecycle

Boot:
  1. Redox init starts 12_dbus.service → dbus-daemon --system
  2. Redox init starts 13_redbear-sessiond.service → redbear-sessiond
     (registers org.freedesktop.login1 on system bus)
  3. Redox init starts 13_seatd.service → seatd

Session launch (redbear-kde-session):
  4. dbus-daemon --system already running
  5. eval $(dbus-launch --sh-syntax)  →  session bus started
  6. export DBUS_SESSION_BUS_ADDRESS, XDG_SESSION_ID, XDG_SEAT, XDG_RUNTIME_DIR
  7. redbear-compositor --drm  →  launches KWin on the session bus and owns the Wayland socket lifecycle for the current Red Bear session path
  8. [later] plasmashell  →  registers org.kde.plasmashell on session bus

5.3 Service Activation Strategy

Service Type	Activation Method	Why
System bus core (login1)	Redox init	Must be running before any desktop session
System bus compat (UPower, NM)	Redox init or D-Bus activation	Can be started lazily, but init is simpler
Session bus KDE services (kglobalaccel, kded6)	D-Bus activation (classic `.service` files)	KDE expects this, standard pattern
Session bus KDE shell (KWin, plasmashell)	Explicit launch in `redbear-kde-session`	Must start in specific order with env vars
Session bus compat (notifications, tray)	D-Bus activation	Standard freedesktop pattern

6. Component Specifications

6.1 `redbear-sessiond` — Session/Seat/Device Broker

Purpose: Provides the org.freedesktop.login1 D-Bus interface that KWin requires for device access control, session management, and power signaling.

Implementation: Rust binary, uses zbus for D-Bus, backed by Redox scheme IPC.

Bus: System bus Bus name: org.freedesktop.login1

D-Bus Interfaces

`/org/freedesktop/login1` — Manager

Interface	Method/Signal	Signature	Description
`org.freedesktop.login1.Manager`	`GetSession`	`s → o`	Returns session object path by ID
	`GetUser`	`u → o`	Returns the current user object path for the bounded active session owner
	`GetUserByPID`	`u → o`	Returns the current user object path for the bounded active session surface
	`ListSessions`	`→ a(susso)`	Lists all active sessions
	`GetSeat`	`s → o`	Returns seat object path
	`ActivateSessionOnSeat`	`ss →`	Marks the bounded session active on the requested seat
	`LockSessions` / `UnlockSessions`	`→`	Updates the bounded session lock hint for KDE session plumbing
	`TerminateUser`	`u →`	Marks the bounded active user session closing
	signal `PrepareForSleep`	`b`	Emitted before/after sleep (false=resume, true=suspend)
	signal `PrepareForShutdown`	`b`	Emitted before/after shutdown
`org.freedesktop.DBus.Properties`	`Get`	`ss → v`	Property access
	`GetAll`	`s → a{sv}`	All properties

`/org/freedesktop/login1/session/c1` — Session

Interface	Method/Signal	Signature	Description
`org.freedesktop.login1.Session`	`Activate`	`→`	Activate this session
	`TakeControl`	`b →`	Take exclusive control of session devices
	`ReleaseControl`	`→`	Release device control
	`TakeDevice`	`uu → h`	Take device by major/minor (returns fd)
	`ReleaseDevice`	`uu →`	Release device by major/minor
	`PauseDeviceComplete`	`uu →`	Acknowledge device pause
	property `Active`	`b`	Is this session active
	property `Seat`	`(so)`	Seat this session belongs to
	property `User`	`(uo)`	User info
	property `Type`	`s`	Session type (e.g. "wayland")
	signal `PauseDevice`	`uus`	Device paused (major, minor, type)
	signal `ResumeDevice`	`uuh`	Device resumed (major, minor, fd)

`/org/freedesktop/login1/seat/seat0` — Seat

Interface	Method/Signal	Signature	Description
`org.freedesktop.login1.Seat`	`SwitchTo`	`u →`	Switch to VT number
	property `ActiveSession`	`(so)`	Currently active session
	property `Sessions`	`a(so)`	All sessions on this seat

Scheme Backing

redbear-sessiond translates login1 D-Bus calls into Redox scheme operations:

login1 Method	Redox Backend
`TakeDevice(major, minor)`	Opens the corresponding scheme path (e.g., `/scheme/drm/card0` for DRM, `/dev/input/eventX` for input) using udev-shim's device enumeration to resolve major/minor → scheme path
`ReleaseDevice(major, minor)`	Closes the scheme file descriptor
`TakeControl(force)`	Records compositor ownership; no kernel-level operation needed (seatd already provides seat arbitration)
`Activate()`	Sets session as active; signals to compositor via D-Bus
`SwitchTo(vt)`	Delegates to `inputd -A <vt>` (existing Redox VT switching)
`PrepareForSleep`	Future/conditional: only available once ACPI sleep eventing exists; currently a known gap in the ACPI stack
`PrepareForShutdown`	Generated from the current ACPI-backed shutdown signal path via `scheme:acpi` / `kstop`

Device Number Mapping

KWin identifies devices by Linux major/minor numbers. Red Bear OS must maintain a stable mapping from (major, minor) → scheme path:

Device Class	Major	Minor Source	Scheme Path
DRM/GPU	226 (Linux DRM major)	card index (0, 1...)	`/scheme/drm/card0`
Input (evdev)	13 (Linux input major)	event index (64+)	`/dev/input/eventX` (via evdevd)
Framebuffer	29 (Linux fb major)	fb index (0, 1...)	`/dev/fbX`

The udev-shim daemon already maintains a device database that maps scheme paths to traditional /dev/ paths with major/minor numbers. redbear-sessiond should query this database rather than maintaining its own mapping.

Configuration

local/recipes/system/redbear-sessiond/
├── recipe.toml              # cargo template, depends on dbus (for libdbus headers)
├── source/
│   ├── Cargo.toml           # zbus + libredox + redox-syscall deps
│   └── src/
│       ├── main.rs          # Daemon entry: fork, signal handling, D-Bus registration
│       ├── manager.rs       # org.freedesktop.login1.Manager interface
│       ├── session.rs       # org.freedesktop.login1.Session interface
│       ├── seat.rs          # org.freedesktop.login1.Seat interface
│       ├── device_map.rs    # major/minor → scheme path resolution (via udev-shim)
│       └── acpi_watcher.rs  # current kstop-backed shutdown watcher; sleep signaling remains future-only until ACPI sleep eventing exists

6.2 D-Bus Service Activation Files

System Bus Service Files

Location: /usr/share/dbus-1/system-services/

org.freedesktop.login1.service:
  [D-BUS Service]
  Name=org.freedesktop.login1
  Exec=/usr/bin/redbear-sessiond
  User=root
  SystemdService=  # intentionally empty — no systemd

Session Bus Service Files

Location: /usr/share/dbus-1/session-services/

org.kde.kglobalaccel.service:
  [D-BUS Service]
  Name=org.kde.kglobalaccel
  Exec=/usr/bin/kglobalaccel

org.kde.kded6.service:
  [D-BUS Service]
  Name=org.kde.kded6
  Exec=/usr/bin/kded6

org.kde.ActivityManager.service:
  [D-BUS Service]
  Name=org.kde.ActivityManager
  Exec=/usr/bin/kactivitymanagerd

org.kde.JobViewServer.service:
  [D-BUS Service]
  Name=org.kde.JobViewServer
  Exec=/usr/bin/kuiserver

org.kde.ksmserver.service:
  [D-BUS Service]
  Name=org.kde.ksmserver
  Exec=/usr/bin/ksmserver

org.freedesktop.Notifications.service:
  [D-BUS Service]
  Name=org.freedesktop.Notifications
  Exec=/usr/bin/redbear-notifications

Recipe for Service Files

Create a redbear-dbus-services recipe that stages all activation files and policies:

local/recipes/system/redbear-dbus-services/
├── recipe.toml              # template = "custom", no source tarball
└── files/
    ├── system-services/
    │   └── org.freedesktop.login1.service
    ├── session-services/
    │   ├── org.kde.kglobalaccel.service
    │   ├── org.kde.kded6.service
    │   ├── org.kde.ActivityManager.service
    │   ├── org.kde.JobViewServer.service
    │   ├── org.kde.ksmserver.service
    │   └── org.freedesktop.Notifications.service
    ├── system.d/
    │   ├── org.freedesktop.login1.conf
    │   └── org.redbear.session.conf
    └── session.d/
        └── org.redbear.session.conf

6.3 D-Bus Policy Configuration

System Bus Policy (`/etc/dbus-1/system.d/org.freedesktop.login1.conf`)

<!DOCTYPE busconfig PUBLIC "-//freedesktop//DTD D-Bus Bus Configuration 1.0//EN"
 "http://www.freedesktop.org/standards/dbus/1.0/busconfig.dtd">
<busconfig>
  <policy user="root">
    <allow own="org.freedesktop.login1"/>
    <allow send_destination="org.freedesktop.login1"/>
    <allow receive_sender="org.freedesktop.login1"/>
  </policy>
  <policy context="default">
    <allow send_destination="org.freedesktop.login1"
           send_interface="org.freedesktop.DBus.Introspectable"/>
    <allow send_destination="org.freedesktop.login1"
           send_interface="org.freedesktop.DBus.Properties"/>
    <allow send_destination="org.freedesktop.login1"
           send_interface="org.freedesktop.login1.Manager"/>
    <allow send_destination="org.freedesktop.login1"
           send_interface="org.freedesktop.login1.Session"/>
    <allow send_destination="org.freedesktop.login1"
           send_interface="org.freedesktop.login1.Seat"/>
    <allow receive_sender="org.freedesktop.login1"/>
  </policy>
</busconfig>

Session Bus Policy (`/etc/dbus-1/session.d/org.redbear.session.conf`)

<!DOCTYPE busconfig PUBLIC "-//freedesktop//DTD D-Bus Bus Configuration 1.0//EN"
 "http://www.freedesktop.org/standards/dbus/1.0/busconfig.dtd">
<busconfig>
  <policy context="default">
    <allow own="org.kde.*"/>
    <allow send_destination="org.kde.*"/>
    <allow receive_sender="org.kde.*"/>
    <allow own="org.freedesktop.Notifications"/>
    <allow send_destination="org.freedesktop.Notifications"/>
    <allow receive_sender="org.freedesktop.Notifications"/>
  </policy>
</busconfig>

6.4 `zbus` Recipe

Add zbus as a recipe so it can be a build dependency for redbear-sessiond and future Rust D-Bus services:

recipes/libs/zbus/  or  local/recipes/libs/zbus/
├── recipe.toml              # cargo template
└── source/
    ├── Cargo.toml           # zbus + zvariant + zbus_names deps
    └── src/
        └── lib.rs           # (upstream zbus crate)

Note: zbus is a pure Rust crate with no C dependencies. It uses async Rust I/O (tokio or async-std) and UNIX domain sockets. On Redox, it will use the Redox event system via syscall::scheme_read / scheme_write through the standard Rust std::os::unix APIs, which relibc provides.

7. Phased Implementation

Phase DB-1: KWin Minimum Viable D-Bus (2–3 weeks)

Goal: KWin can start as Wayland compositor with a real session broker.

Work items:

#	Task	Acceptance Criteria
1.1	Add `zbus` recipe to recipe tree	`make r.zbus` succeeds, crate stages to sysroot
1.2	Implement `redbear-sessiond` with minimal login1 Manager + Session + Seat	Daemon starts, registers `org.freedesktop.login1` on system bus
1.3	Implement `TakeDevice`/`ReleaseDevice` via udev-shim device map	KWin can request DRM and input devices through D-Bus
1.4	Implement `TakeControl`/`ReleaseControl`	KWin can take exclusive session ownership
1.5	Create D-Bus policy files for login1	Policy allows session compositor to call login1 methods
1.6	Create D-Bus activation `.service` file for login1	`redbear-sessiond` can be activated or init-started
1.7	Add `redbear-sessiond` to `redbear-full.toml` init services	Service starts before KWin in boot sequence
1.8	Wire `XDG_SESSION_ID`, `XDG_SEAT`, `XDG_RUNTIME_DIR` in the KDE session launcher	KWin sees a valid session environment
1.9	Validate: `dbus-send --system --dest=org.freedesktop.login1 --print-reply /org/freedesktop/login1 org.freedesktop.login1.Manager.ListSessions`	Returns non-empty session list
1.10	Validate: `dbus-send --session --dest=org.kde.KWin /KWin org.kde.KWin.supportInformation`	Returns non-empty KWin info string

Exit criteria:

redbear-sessiond — binary present, service wired; runtime registration requires QEMU boot
login1.Manager.ListSessions — implemented in sessiond; runtime validation requires QEMU
KWin TakeDevice — DRM/input device methods structurally present; runtime requires QEMU with DRM
KWin D-Bus registration — reduced-feature real build provides the surface; runtime proof requires Qt6Quick/QML downstream validation
org.kde.KWin.supportInformation — structurally implemented; runtime proof requires real KWin
Bounded compositor-session survival — validation compositor path proven; real KWin runtime proof requires Qt6Quick/QML downstream validation

Dependencies: relibc eventfd/timerfd/signalfd (already built), evdevd, udev-shim, seatd

Phase DB-2: Desktop Session Services (2–3 weeks)

Goal: plasma-workspace can start with essential session services.

Work items:

#	Task	Acceptance Criteria
2.1	Create `redbear-dbus-services` recipe with all session `.service` files	Files staged to `/usr/share/dbus-1/session-services/`
2.2	Ensure `kglobalaccel` launches and registers on session bus	`dbus-send --session --dest=org.kde.kglobalaccel ...` succeeds
2.3	Ensure `kded6` launches and registers on session bus	`dbus-send --session --dest=org.kde.kded6 ...` succeeds
2.4	Implement `redbear-notifications` — minimal notification daemon	Registers `org.freedesktop.Notifications`, can receive and display a notification
2.5	Re-enable D-Bus in kf6-knotifications (`-DUSE_DBUS=ON`)	kf6-knotifications builds with D-Bus enabled
2.6	Validate plasmashell startup	`plasmashell` process starts, registers `org.kde.plasmashell`
2.7	Validate OSD service	`org.kde.osdService` responds to brightness/volume queries

Exit criteria:

kglobalaccel — activation file staged; runtime registration requires QEMU
kded6 — activation file staged; runtime registration requires QEMU
org.freedesktop.Notifications — service files present; runtime Notify() requires QEMU
kf6-knotifications — builds with D-Bus enabled (USE_DBUS=ON in recipe)
plasmashell — plasma-workspace enabled in config; runtime registration requires full Plasma session (gated on Qt6Quick + real KWin)
org.freedesktop.UPower — redbear-upower scaffold present; full surface requires ACPI validation beyond current bounded proof
org.freedesktop.UDisks2 — redbear-udisks scaffold present; device enumeration requires hardware
kf6-solid — UPower/UDisks2 backends deferred; ACPI power surface validated within bounded proof
Shutdown signal — login1 interface structurally present; sleep signal requires ACPI sleep eventing
org.freedesktop.PolicyKit1 — deferred; not on critical path for minimal Plasma session
KAuth polkit backend — fake backend sufficient for bounded proof; real polkit deferred

Phase DB-5: Polish and Full Integration (ongoing)

Goal: Complete D-Bus coverage for full KDE Plasma desktop experience.

Work items:

#	Task	Acceptance Criteria
5.1	Implement `org.freedesktop.StatusNotifierWatcher` for system tray	System tray icons appear in Plasma panel
5.2	Implement `org.kde.JobViewServer` for job progress	File copy/move operations show progress in Plasma
5.3	Implement `org.kde.ksmserver` for session management	Logout/restart/shutdown work from Plasma menu
5.4	Implement `org.freedesktop.ScreenSaver` for screen locking	Screen locks on timeout and manual lock
5.5	Enable kf6-kwallet in redbear-full (recipe exists in-tree)	KWallet stores and retrieves passwords
5.6	Re-enable D-Bus in kf6-kio	KIO uses D-Bus for service activation
5.7	Promote dbus recipe from WIP to production	Remove #TODO, add BLAKE3, move from `recipes/wip/services/` to `recipes/services/`

Dependencies: Phases DB-1 through DB-4 complete

8. Integration with Console-to-KDE Plan

This D-Bus plan maps directly onto the phases in CONSOLE-TO-KDE-DESKTOP-PLAN.md v4.0:

Desktop Plan Phase	D-Bus Plan Phase	What D-Bus delivers
Phase 1: Runtime Substrate Validation	(no D-Bus work — substrate is below D-Bus)	—
Phase 2: Wayland Compositor Proof	DB-1: KWin MVP	login1 session broker, system/session bus validation
Phase 3: KWin Desktop Session	DB-1 (completion) + DB-2 (session services)	kglobalaccel, kded6, notifications, plasmashell D-Bus
Phase 4: KDE Plasma Session	DB-3 (hardware services) + DB-4 (network/policy)	UPower once the ACPI power surface is honest, udisks2, NM, polkit, full session
Phase 5: Hardware GPU Enablement	(D-Bus not on critical path for GPU)	login1 TakeDevice for GPU fd passing

Modifications to Console-to-KDE Plan

The following updates should be applied to CONSOLE-TO-KDE-DESKTOP-PLAN.md:

Phase 2 — add D-Bus validation tasks:

#	Task	Acceptance Criteria
2.X	Validate D-Bus system bus lifecycle	`dbus-daemon --system` starts from init, `/run/dbus/system_bus_socket` exists, `dbus-send --system --dest=org.freedesktop.DBus --print-reply /org/freedesktop/DBus org.freedesktop.DBus.ListNames` returns a list including `org.freedesktop.login1`
2.X	Validate D-Bus session bus lifecycle	`dbus-launch --sh-syntax` sets `DBUS_SESSION_BUS_ADDRESS`, `dbus-send --session --print-reply /org/freedesktop/DBus org.freedesktop.DBus.ListNames` returns a non-empty list

Phase 3 — update D-Bus task 3.4:

Replace the existing task 3.4 with:

#	Task	Acceptance Criteria
3.4	Validate complete D-Bus session stack	`org.freedesktop.login1.Manager.ListSessions` returns valid data; `org.kde.KWin.supportInformation` returns non-empty string; `kglobalaccel` registered on session bus

Phase 4 — add D-Bus service milestone:

#	Task	Acceptance Criteria
4.X	D-Bus hardware services operational	`org.freedesktop.UPower` and `org.freedesktop.UDisks2` register on system bus; UPower consumer claims stay bounded until the ACPI power surface is validated
4.X	D-Bus network service operational	Deferred — Red Bear OS uses `redbear-netctl`, not NetworkManager

9. D-Bus Service Dependency Map

9.1 System Bus Services

org.freedesktop.DBus (dbus-daemon itself — always present)
│
├── org.freedesktop.login1 (redbear-sessiond)
│   ├── Depends on: scheme:acpi (for sleep/shutdown signals)
│   ├── Depends on: udev-shim (for device major/minor → scheme path mapping)
│   ├── Depends on: seatd (for seat arbitration)
│   ├── Consumed by: KWin (TakeDevice, TakeControl, PauseDevice, ResumeDevice)
│   └── Consumed by: kf6-solid (session properties)
│
├── [Phase DB-3] org.freedesktop.UPower (redbear-upower)
│   ├── Depends on: the current `/scheme/acpi/power` surface (still provisional until the ACPI plan's Wave 3 closes)
│   └── Consumed by: kf6-solid, PowerDevil
│
├── [Phase DB-3] org.freedesktop.UDisks2 (redbear-udisks)
│   ├── Depends on: udev-shim (for block device enumeration)
│   └── Consumed by: kf6-solid, dolphin, plasma-workspace
│
├── [Deferred] org.freedesktop.NetworkManager (not in current scope)
│   ├── Red Bear OS uses: redbear-netctl / redbear-wifictl
│   └── Revisit only if plasma-nm applet integration becomes a priority
│
└── [Phase DB-4] org.freedesktop.PolicyKit1 (redbear-polkit)
    └── Consumed by: KAuth, privileged desktop actions

9.2 Session Bus Services

org.freedesktop.DBus (dbus-daemon — always present)
│
├── org.kde.KWin (KWin — self-registers)
│   ├── Object: /KWin
│   ├── Interfaces: org.kde.KWin, org.kde.KWin.VirtualDesktopManager
│   ├── Consumed by: plasmashell, kcm modules
│   └── Depends on: org.freedesktop.login1 (system bus)
│
├── org.kde.plasmashell (plasmashell — self-registers)
│   ├── Object: /PlasmaShell
│   ├── Interfaces: org.kde.PlasmaShell, org.kde.osdService
│   └── Consumed by: KWin (OSD calls), KDE apps
│
├── org.kde.kglobalaccel (kglobalaccel daemon)
│   ├── Activated by: .service file
│   └── Consumed by: all KDE apps (global shortcuts)
│
├── org.kde.kded6 (KDE daemon)
│   ├── Activated by: .service file
│   └── Consumed by: KDE modules (status notifier, etc.)
│
├── [Phase DB-2] org.freedesktop.Notifications (redbear-notifications)
│   ├── Activated by: .service file
│   └── Consumed by: kf6-knotifications, all KDE apps
│
├── [Phase DB-5] org.freedesktop.StatusNotifierWatcher
│   └── Consumed by: system tray, plasma panel
│
└── [Phase DB-5] org.kde.JobViewServer
    └── Consumed by: kf6-kjobwidgets, dolphin, file operations

9.3 KDE Framework D-Bus Consumer Map

KF6 Module	D-Bus Usage	Current Build Flag	Re-enable Condition
kf6-kdbusaddons	Core D-Bus wrappers	✅ Enabled	Already built
kf6-kservice	Service/plugin discovery	✅ Enabled (via kdbusaddons)	Already built
kf6-kglobalaccel	Global shortcuts via D-Bus	✅ Enabled	Needs kglobalaccel daemon running
kf6-knotifications	Desktop notifications	✅ `-DUSE_DBUS=ON`	Enabled against current notification scaffold; build-verified; supplementary QEMU runtime validation
kf6-solid	Hardware enumeration	⚠️ `-DUSE_DBUS=OFF`	Re-enable after UPower/udisks2 (DB-3)
kf6-kio	D-Bus service activation	⚠️ `-DUSE_DBUS=OFF`	Re-enable after core services proven (DB-3)
kf6-kwallet	Session D-Bus stable	⚠️ Not in enabled subset	Real API-only build exists in-tree (DB-5)
kf6-kauth	Privileged actions	⚠️ Fake backend	Blocked until `PolkitQt6-1` is packaged and recipe switched off FAKE
kf6-kidletime	Idle detection	✅ Builds	Needs ScreenSaver D-Bus for full function
kf6-kjobwidgets	Job progress	✅ Builds	Needs JobViewServer (DB-5)

10. Security Model

10.1 Two-Layer Model

Layer 1: Redox Schemes (kernel-enforced capability security)
  ├── scheme:drm — only accessible to processes with explicit FD
  ├── scheme:pci — only accessible to pcid-spawner-launched drivers
  ├── scheme:input — only accessible to evdevd (which creates /dev/input/)
  └── scheme:net — only accessible to network daemons

Layer 2: D-Bus Policy (daemon-enforced access control)
  ├── System bus: XML policy files in /etc/dbus-1/system.d/
  ├── Session bus: XML policy files in /etc/dbus-1/session.d/
  └── Peer credentials: UID/GID verified via UNIX socket SCM_CREDENTIALS

Rule: Schemes are the real authority. D-Bus policy only gates who may ask a broker service to perform an operation. The broker service holds the scheme capability, not the client.

10.2 D-Bus Authentication

dbus-daemon uses the EXTERNAL SASL mechanism, which authenticates clients by their UNIX socket credentials (UID/GID via SCM_CREDENTIALS). On Redox, this requires:

relibc's SO_PASSCRED / SCM_CREDENTIALS support on Redox UNIX domain sockets
getpeereid() or equivalent — for the bus daemon to verify the connecting process's UID

Current repo status:

relibc now exposes SO_PASSCRED, SO_PEERCRED, SCM_CREDENTIALS, and getpeereid() in the active tree
the bounded relibc test path now covers peer-credential lookup (SO_PEERCRED) and credential delivery via recvmsg() / SCM_CREDENTIALS on Redox UNIX domain sockets

That means the supplementary D-Bus risk is no longer raw absence of the credential path in relibc; it is broader desktop/runtime trust and integration with the real bus daemons.

10.3 Policy Granularity

Keep D-Bus XML policies coarse-grained:

Who may own a bus name (e.g., only root may own org.freedesktop.login1)
Who may send to a destination (e.g., any user may send to org.freedesktop.login1.Manager)
Who may receive from a sender (e.g., any user may receive signals from login1)

Keep fine-grained authorization inside the Rust service:

redbear-sessiond checks whether the requesting process's UID matches the active session owner
redbear-sessiond checks whether the requesting process is the compositor before granting TakeControl()
redbear-polkit checks at-console status before authorizing privileged actions

Do NOT try to map every scheme permission into D-Bus XML policy.

10.4 Session Bus Isolation

The session bus must only be accessible to the owning user:

DBUS_SESSION_BUS_ADDRESS should point to a socket in XDG_RUNTIME_DIR (e.g., /tmp/run/user/0/)
Socket permissions must be 0600 (owner-only)
No TCP transport — UNIX sockets only (TCP is deprecated in D-Bus anyway)

11. Build Recipe Changes

11.1 New Recipes

Recipe	Location	Template	Dependencies
`zbus`	`local/recipes/libs/zbus/`	`custom` (build-ordering marker)	none
`redbear-sessiond`	`local/recipes/system/redbear-sessiond/`	`cargo`	zbus, libredox, redox-syscall
`redbear-dbus-services`	`local/recipes/system/redbear-dbus-services/`	`custom`	dbus (for staging dirs)
`redbear-notifications`	`local/recipes/system/redbear-notifications/`	`cargo`	zbus
`redbear-upower`	`local/recipes/system/redbear-upower/`	`cargo`	zbus
`redbear-udisks`	`local/recipes/system/redbear-udisks/`	`cargo`	zbus
`redbear-polkit`	`local/recipes/system/redbear-polkit/`	`cargo`	zbus

Note: redbear-nm (NetworkManager facade) is NOT in scope. Red Bear OS uses its native redbear-netctl for network management. NM may be revisited if a future KDE Plasma NM applet integration is needed.

11.2 Modified Recipes

Recipe	Change	Phase
`dbus`	Promote from WIP, add runtime validation	DB-5
`kf6-knotifications`	Change `-DUSE_DBUS=OFF` → `-DUSE_DBUS=ON`	DB-2 ✅ done
`kf6-solid`	Change `-DUSE_DBUS=OFF` → `-DUSE_DBUS=ON`, re-enable UPower backend	DB-3
`kf6-kio`	Change `-DUSE_DBUS=OFF` → `-DUSE_DBUS=ON`	DB-5
`kf6-kwallet`	Enable in config (recipe exists in-tree)	DB-5
`qtbase` (host)	Consider enabling FEATURE_dbus=ON for host tools (qdbuscpp2xml/qdbusxml2cpp)	DB-2

11.3 Config Changes

redbear-full.toml additions:

[packages]
# D-Bus session/seat broker
redbear-sessiond = {}
redbear-dbus-services = {}

# [[files]] — redbear-sessiond init service
[[files]]
path = "/usr/lib/init.d/13_redbear-sessiond.service"
data = """
[unit]
description = "Red Bear session broker (login1)"
requires_weak = [
    "12_dbus.service",
]

[service]
cmd = "redbear-sessiond"
type = "oneshot_async"
"""

KDE session launcher updates:

# After dbus-launch, set session variables
export XDG_SESSION_ID=c1        # redbear-sessiond session ID
export XDG_SEAT=seat0
export XDG_SESSION_TYPE=wayland
export XDG_RUNTIME_DIR=/tmp/run/user/0
export XDG_CURRENT_DESKTOP=KDE

# Ensure session bus environment is in D-Bus activation environment
dbus-update-activation-environment \
    WAYLAND_DISPLAY \
    XDG_SESSION_ID \
    XDG_SEAT \
    XDG_SESSION_TYPE \
    XDG_RUNTIME_DIR \
    XDG_CURRENT_DESKTOP \
    KDE_FULL_SESSION \
    DISPLAY

12. Testing and Validation

12.1 Phase DB-1 Tests

# System bus basic
dbus-send --system --dest=org.freedesktop.DBus --print-reply \
    /org/freedesktop/DBus org.freedesktop.DBus.ListNames

# login1 presence
dbus-send --system --dest=org.freedesktop.login1 --print-reply \
    /org/freedesktop/login1 org.freedesktop.login1.Manager.ListSessions

# login1 seat
dbus-send --system --dest=org.freedesktop.login1 --print-reply \
    /org/freedesktop/login1/seat/seat0 org.freedesktop.DBus.Properties.GetAll \
    string:"org.freedesktop.login1.Seat"

# Session bus basic
dbus-send --session --dest=org.freedesktop.DBus --print-reply \
    /org/freedesktop/DBus org.freedesktop.DBus.ListNames

# KWin registration (after KWin starts)
dbus-send --session --dest=org.kde.KWin --print-reply \
    /KWin org.kde.KWin.supportInformation

12.2 Phase DB-2 Tests

# kglobalaccel
dbus-send --session --dest=org.kde.kglobalaccel --print-reply \
    /kglobalaccel org.freedesktop.DBus.Introspectable.Introspect

# kded6
dbus-send --session --dest=org.kde.kded6 --print-reply \
    /kded org.freedesktop.DBus.Introspectable.Introspect

# Notifications
dbus-send --session --dest=org.freedesktop.Notifications --print-reply \
    /org/freedesktop/Notifications org.freedesktop.Notifications.Notify \
    string:"test" uint32:0 string:"" string:"Test" string:"Body" array:string:{} dict:string:string:{} int32:5000

# plasmashell
dbus-send --session --dest=org.kde.plasmashell --print-reply \
    /PlasmaShell org.freedesktop.DBus.Introspectable.Introspect

12.3 QEMU Validation Script

Create local/scripts/test-dbus-qemu.sh:

#!/bin/sh
# Validates D-Bus stack in QEMU-booted Red Bear OS
# Usage: ./local/scripts/test-dbus-qemu.sh --check

echo "=== D-Bus System Bus ==="
echo "System bus socket:"
ls -la /run/dbus/system_bus_socket 2>&1

echo "Bus names:"
dbus-send --system --dest=org.freedesktop.DBus --print-reply \
    /org/freedesktop/DBus org.freedesktop.DBus.ListNames 2>&1

echo "login1 sessions:"
dbus-send --system --dest=org.freedesktop.login1 --print-reply \
    /org/freedesktop/login1 org.freedesktop.login1.Manager.ListSessions 2>&1

echo ""
echo "=== D-Bus Session Bus ==="
echo "Session bus address:"
echo "$DBUS_SESSION_BUS_ADDRESS"

echo "Session bus names:"
dbus-send --session --dest=org.freedesktop.DBus --print-reply \
    /org/freedesktop/DBus org.freedesktop.DBus.ListNames 2>&1

13. Risks and Mitigations

13.1 Technical Risks

Risk	Impact	Likelihood	Mitigation
UNIX socket credential passing regresses on Redox	D-Bus authentication fails	Medium	Keep the relibc UDS credential tests in the preserved proof path; if broken again, fall back to cookie auth or patch relibc
KWin login1 expectations exceed our minimal subset	KWin crashes or refuses to start	Medium	Start with KWin's Noop fallback; add methods incrementally as KWin logs errors
zbus async runtime conflicts with Redox event system	zbus doesn't build or run	Low	zbus supports multiple async runtimes; test tokio + Redox early
D-Bus service activation files not picked up by dbus-daemon	Services must be started manually	Low	dbus-daemon 1.16.2 supports classic activation; verify search path in redox.patch
Device major/minor mapping unstable	TakeDevice returns wrong device	Medium	Use udev-shim as single source of truth; add validation tests
PAM not available for elogind-like session tracking	Cannot use elogind directly	Certain	That's why we're building redbear-sessiond — no PAM dependency
Peer credential path behaves differently under real dbus-daemon load	System bus policy can't verify UIDs reliably	Medium	The relibc credential path is now present and bounded-tested; next tighten with real dbus-daemon/session-bus runtime validation

13.2 Integration Risks

Risk	Impact	Mitigation
KDE Plasma 6 accumulates more systemd assumptions	More D-Bus services needed than anticipated	Monitor KDE Plasma releases; test each upgrade
Re-enabling D-Bus in kf6 components exposes build failures	Build breakage in previously-stable recipes	Re-enable one component at a time, with CI gating
Init service ordering conflicts	redbear-sessiond starts before dbus-daemon	Use `requires_weak = ["12_dbus.service"]` in init config

13.3 Escalation Triggers

If TakeDevice() cannot be made to work via major/minor → scheme path mapping: Add a small Redox-only KWin session backend that talks to the native seat/device broker directly (bypasses D-Bus for device access). Keep the rest of the D-Bus architecture unchanged.
If zbus cannot build on Redox (async runtime incompatibility): Fall back to libdbus-1 C bindings for Rust services (via the dbus crate). Less ergonomic but proven to work with the existing dbus build.
If KDE hard-requires more freedesktop services than expected: Add them as individual compatibility daemons, not a generic bridge. Each daemon wraps exactly one freedesktop contract.

14. Qt 6.11 D-Bus Coverage

This appendix closes an important scoping gap in the plan. Qt 6.11 itself already carries D-Bus coverage for the Redox target, and the KDE build stack already has a working code generation path for D-Bus XML tooling during cross-compilation. The missing pieces are higher-level freedesktop service contracts and the staged re-enablement of KF6 components that were intentionally built with D-Bus disabled.

14.1 Qt Build Configuration

The current Qt 6.11 setup splits D-Bus support differently between target and host builds.

Target build (qtbase for Redox):

-DFEATURE_dbus=ON (line 419 of recipe.toml)
"dbus" listed as build dependency (line 16)
Qt6DBus module built and staged
libQt6DBus.so.6.11.0 staged to sysroot

Host build (qtbase-host):

-DFEATURE_dbus=OFF (line 104)
Profile name: qtbase-host-6.11.0-gui-xml-wayland-no-qdbus-host (line 63)
qdbuscpp2xml and qdbusxml2cpp subdirectories disabled via Python patching (lines 71-74)
These tools are needed at BUILD time by kf6-kdbusaddons, kwin, kf6-kio for D-Bus XML → C++ code generation

The practical result is that QtDBus support exists in the target sysroot today. Build-time D-Bus tooling for host-side code generation is the only area still running through a workaround path.

14.2 qdbuscpp2xml/qdbusxml2cpp Provisioning

The current provisioning strategy is intentionally pragmatic.

Since the host build disables D-Bus, KDE recipes provision these tools via symlinks:

kf6-kdbusaddons (lines 22-32): First tries ${HOST_BUILD}/libexec/$tool, then falls back to /usr/bin/qdbuscpp2xml and /usr/bin/qdbusxml2cpp from the host system
kwin (line 67): for tool in moc rcc uic qdbuscpp2xml qdbusxml2cpp wayland-scanner; do
kf6-kio (line 33): Same pattern as kwin

The host system packages provide these tools during cross-compilation. This is a pragmatic workaround, not a long-term solution. Future improvement: enable FEATURE_dbus=ON in the host build once D-Bus session bus validation passes on the host toolchain.

14.3 KF6 Components with D-Bus Disabled

The following KF6 components currently build with -DUSE_DBUS=OFF. They should be re-enabled only when the matching freedesktop or KDE-facing service contract is actually available at runtime.

Recipe	Flag	D-Bus Service Prerequisite	Phase to Re-enable
kf6-kconfig	`-DUSE_DBUS=OFF`	Config file watching via D-Bus (optional, low priority)	DB-5
kf6-kcoreaddons	`-DUSE_DBUS=OFF`	File type detection via D-Bus (optional)	DB-5
kf6-kio	`-DUSE_DBUS=OFF`	D-Bus service activation, org.kde.KIO::*	DB-5
kf6-knotifications	`-DUSE_DBUS=ON`	org.freedesktop.Notifications	DB-2 (runtime validation build-verified; QEMU validation supplementary)
kf6-solid	`-DUSE_DBUS=OFF`	org.freedesktop.UPower + org.freedesktop.UDisks2 + org.freedesktop.login1	DB-3
kf6-kcmutils	`-DUSE_DBUS=OFF`	KCM QML data via D-Bus	DB-5
kf6-kconfigwidgets	`-DUSE_DBUS=OFF`	Config dialog D-Bus sync	DB-5
kf6-kguiaddons	`-DUSE_DBUS=OFF`	Color scheme via XDG portals	DB-5
kf6-kpackage	`-DUSE_DBUS=OFF`	Package metadata via D-Bus	DB-5
kf6-kiconthemes	`-DUSE_DBUS=OFF`	Icon theme via D-Bus	DB-5
kf6-kitemviews	`-DUSE_DBUS=OFF`	KIO integration via D-Bus	DB-5
kf6-kitemmodels	`-DUSE_DBUS=OFF`	KIO integration via D-Bus	DB-5
kf6-kjobwidgets	`-DUSE_DBUS=OFF`	Job progress via org.kde.JobViewServer	DB-5
kirigami	`-DUSE_DBUS=OFF`	Cross-device sharing	DB-5
plasma-framework	`-DUSE_DBUS=OFF`	Plasma widget D-Bus integration	DB-5

14.4 Re-enablement Priority Order

Re-enablement must follow service availability, not package build order.

DB-1 (now): redbear-sessiond provides org.freedesktop.login1 → kf6-solid UPower backend can connect (but needs UPower daemon too)
DB-2: redbear-notifications provides org.freedesktop.Notifications → re-enable kf6-knotifications
DB-3: redbear-upower provides org.freedesktop.UPower → re-enable kf6-solid (with UPower backend)
DB-4: redbear-udisks provides org.freedesktop.UDisks2 → kf6-solid UDisks2 backend
DB-5: Full desktop services → re-enable kf6-kio, kf6-kjobwidgets, kf6-kcmutils, and all supplementary components

The key insight: QtDBus is NOT the gap. Qt6DBus builds and kf6-kdbusaddons provides the convenience layer. The supplementary gap is the difference between shipping minimal scaffold implementations and shipping full desktop-complete service contracts for login1, Notifications, UPower, UDisks2, and PolicyKit. NetworkManager remains deferred and is not part of the current Red Bear OS implementation scope.

Phase 3/4 D-Bus Improvement Plan (2026-04-25 Assessment)

Assessment scope: All Red Bear D-Bus service implementations (redbear-sessiond, redbear-notifications, redbear-upower, redbear-udisks, redbear-polkit), plus the dbus-daemon itself, conducted via 4 parallel evaluation agents (Oracle + 2 explore + librarian).

Key finding: Phase 2 (kwin_wayland --virtual) should work without D-Bus changes. KWin falls back to NoopSession when logind is unavailable, and the Noop backend bypasses login1 entirely.

Key finding: Phase 3 has one hard gate: TakeDevice FD passing. This cannot be bypassed.

Assessment Summary

Fragility ratings across services:

Service	Rating	Primary concern
`redbear-sessiond`	5/5	login1 is the critical path for DRM compositor
`redbear-polkit`	5/5 security	Always-permit is not a production security model
`dbus-daemon`	2/5	24-line patch is stable but not validated under real session bus load
`redbear-notifications`	2-3/5	Logs to stderr only; no ActionInvoked signal
`redbear-upower`	2-3/5	Provisional ACPI surface; no Changed signal; polling deferred (requires QEMU validation)
`redbear-udisks`	2-3/5	Read-only; no mount/unmount operations

Phase 2 assessment: D-Bus is NOT on the critical path for kwin_wayland --virtual. The NoopSession backend in KWin bypasses logind entirely, which means Phase 2 compositor bring-up should succeed without D-Bus changes.

Phase 3 hard gate: TakeDevice FD passing + PauseDevice/ResumeDevice signal emission. This is required for KWin to own real DRM and input devices through the freedesktop session protocol. No bypass exists.

Phase 4 broader surface: kglobalaccel binary, kded6 binary, StatusNotifierWatcher, Inhibit methods, session identity derivation.

Phase 3 Gate (DRM Compositor) — Required D-Bus Changes

Four fixes are required before KWin can use real hardware devices through login1:

#	Fix	Current state	Required change
1	`Manager.Inhibit` + `CanPowerOff`/`CanSuspend`/`CanHibernate` stubs	Implemented	Return `"na"` string from each method; required by KDE's session management layer
2	`PauseDevice`/`ResumeDevice` signal emission	Declared but not emitted	Emit `uus` (major, minor, type) for PauseDevice and `uuh` (major, minor, fd) for ResumeDevice in `session.rs` when device state changes
3	Dynamic device enumeration	Static `device_map.rs` with hardcoded major/minor	Query udev-shim at runtime for major/minor -> scheme path mapping; remove hardcoded lookup table
4	Session methods	`SetIdleHint`, `SetLockedHint`, `SetType`, `Terminate` return errors; runtime validation requires QEMU

Phase 4 Gate (KDE Plasma Session) — Required D-Bus Changes

#	Improvement	Current state	Required change
1	`StatusNotifierWatcher: activation file staged	Register `org.freedesktop.StatusNotifierWatcher` on session bus; track registered items, emit `ItemRegistered`/`ItemUnregistered` signals
2	`kglobalaccel` binary build	KDE app recipe builds library, daemon binary is a separate recipe step	Add `kglobalaccel` binary to `local/recipes/kde/kf6-kglobalaccel/` or create separate recipe
3	`kded6` binary build	KDE app recipe builds library, daemon binary is a separate recipe step	Add `kded6` binary to `local/recipes/kde/kf6-kded6/` or create separate recipe
4	Session identity derivation	Hardcoded to `c1`, `root`, `uid=0`	Query real session environment variables (`XDG_SESSION_ID`, `XDG_SEAT`) and derive identity from the actual login session
5	`UPower Changed` signal emission + polling	No signals, no polling	Emit `Changed` signal when power state changes; implement property polling for `OnBattery`, `Percentage`, `TimeToEmpty`
6	`Notifications ActionInvoked` signal + capabilities	Activation file staged; runtime deferred	Emit `ActionInvoked(uint32, string)` when user clicks notification action; expand `GetCapabilities` to include `body`, `actions`, `icon-static`
7	Stoppable daemons	Services use `supplementary()` with no shutdown channel	Replace `supplementary()` in all services with proper shutdown signal channels; enable service restart and clean shutdown

KWin Method-by-Method Readiness Matrix

KWin D-Bus call	Current impl	Phase 2 needed	Phase 3 needed
`GetSession("auto")`	via NoopSession	No (bypasses logind)	Yes
`TakeControl(false)`	Via login1	No	Yes
`TakeDevice(226, 0)` (DRM)	Via DeviceMap	No	Yes (critical)
`TakeDevice(13, 64+)` (input)	Via DeviceMap	No	Yes (critical)
`PauseDevice` signal	Declared, not emitted	No	Yes (critical)
`ResumeDevice` signal	Declared, not emitted	No	Yes (critical)
`Seat.SwitchTo`	Via login1	No	Yes
`Manager.Inhibit`	Implemented	No	Yes
`CanPowerOff`/`CanSuspend`/`CanHibernate`	Implemented	No	Yes
`PrepareForShutdown`	Via ACPI	No	Yes
`PrepareForSleep`	Declared, not emitted	No	Yes

Completeness by Service

Service	Methods real	Total expected	Completeness
`login1.Manager`	3	~30+	~10%
`login1.Session`	7	~15+	~47%
`login1.Seat`	1	5	~20%
`Notifications`	4	~5	~80%
`UPower`	3	~5	~60%
`UDisks2`	4	~8+	~50%
`PolicyKit1`	3	~6+	~50%

Implemented KDE D-Bus Services

Service	Used by	Status	Impact
`org.kde.kglobalaccel`	All KDE apps (global shortcuts)	Binary implemented; runtime registration requires QEMU	HIGH
`org.kde.kded6`	KDE daemon (status notifier, etc.)	Binary implemented; runtime registration requires QEMU	HIGH
`org.freedesktop.StatusNotifierWatcher: activation file staged	MEDIUM
`org.kde.ksmserver: activation file staged	MEDIUM
`org.freedesktop.ScreenSaver`	Screen locking	Activation file staged; runtime deferred	MEDIUM

Implementation Priority Order

redbear-sessiond Phase 3 methods (enables DRM compositor session)
Dynamic device enumeration (enables non-static hardware discovery)
Stoppable daemons (enables testing and restart)
StatusNotifierWatcher (enables system tray)
UPower polling + signals (enables battery applet)
Session identity improvements (enables non-root sessions)

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Red Bear OS D-Bus Integration Plan

1. Executive Summary

2. Architecture Principles

2.1 Schemes = Native Resource Plane, D-Bus = Desktop Compatibility Plane

2.2 Use Existing Contracts, Don't Invent New Ones

2.3 No Generic Scheme→D-Bus Bridge

2.4 Rust-Native for New Services, C for Existing Daemons

3. Current State Assessment

3.1 What Exists and Works

3.2 What Exists But Is Incomplete

3.3 What Ships Today (Scaffolds and Deferred Items)

4. Gap Analysis

4.1 Critical Path Gaps (blocks KWin compositor)

4.2 Desktop Session Gaps (blocks plasma-workspace)

4.3 Full Desktop Gaps (blocks complete KDE Plasma)

4.4 Build System Gaps

5. Architecture Design

5.1 Overall Stack

5.2 D-Bus Service Lifecycle

5.3 Service Activation Strategy

6. Component Specifications

6.1 redbear-sessiond — Session/Seat/Device Broker

D-Bus Interfaces

/org/freedesktop/login1 — Manager

/org/freedesktop/login1/session/c1 — Session

/org/freedesktop/login1/seat/seat0 — Seat

Scheme Backing

Device Number Mapping

Configuration

6.2 D-Bus Service Activation Files

System Bus Service Files

Session Bus Service Files

Recipe for Service Files

6.3 D-Bus Policy Configuration

System Bus Policy (/etc/dbus-1/system.d/org.freedesktop.login1.conf)

Session Bus Policy (/etc/dbus-1/session.d/org.redbear.session.conf)

6.4 zbus Recipe

7. Phased Implementation

Phase DB-1: KWin Minimum Viable D-Bus (2–3 weeks)

Phase DB-2: Desktop Session Services (2–3 weeks)

Phase DB-5: Polish and Full Integration (ongoing)

8. Integration with Console-to-KDE Plan

Modifications to Console-to-KDE Plan

9. D-Bus Service Dependency Map

9.1 System Bus Services

9.2 Session Bus Services

9.3 KDE Framework D-Bus Consumer Map

10. Security Model

10.1 Two-Layer Model

10.2 D-Bus Authentication

10.3 Policy Granularity

10.4 Session Bus Isolation

11. Build Recipe Changes

11.1 New Recipes

11.2 Modified Recipes

11.3 Config Changes

12. Testing and Validation

12.1 Phase DB-1 Tests

12.2 Phase DB-2 Tests

12.3 QEMU Validation Script

13. Risks and Mitigations

13.1 Technical Risks

13.2 Integration Risks

13.3 Escalation Triggers

14. Qt 6.11 D-Bus Coverage

14.1 Qt Build Configuration

14.2 qdbuscpp2xml/qdbusxml2cpp Provisioning

14.3 KF6 Components with D-Bus Disabled

14.4 Re-enablement Priority Order

Phase 3/4 D-Bus Improvement Plan (2026-04-25 Assessment)

Assessment Summary

Phase 3 Gate (DRM Compositor) — Required D-Bus Changes

Phase 4 Gate (KDE Plasma Session) — Required D-Bus Changes

KWin Method-by-Method Readiness Matrix

Completeness by Service

Implemented KDE D-Bus Services

Implementation Priority Order

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Raw Permalink Blame History

6.1 `redbear-sessiond` — Session/Seat/Device Broker

`/org/freedesktop/login1` — Manager

`/org/freedesktop/login1/session/c1` — Session

`/org/freedesktop/login1/seat/seat0` — Seat

System Bus Policy (`/etc/dbus-1/system.d/org.freedesktop.login1.conf`)

Session Bus Policy (`/etc/dbus-1/session.d/org.redbear.session.conf`)

6.4 `zbus` Recipe