broker-proxy returns "Bus name com.microsoft.identity.broker1 already owned"

[synthead]

If I enable broker-proxy...

$ intuneme config broker-proxy enable
  Broker proxy enabled.
  D-Bus activation file installed: /home/myuser/.local/share/dbus-1/services/com.microsoft.identity.broker1.service
  The proxy will start automatically on next 'intuneme start',
  or when a host app calls the broker.

...then run intuneme start, like so...

$ intuneme start
  Checking sudo credentials...
  Booting container...
  Waiting for container to boot...
  Enabling linger for container user...
  Waiting for container session bus...
  Container and broker proxy running.
  Host apps can now use SSO via com.microsoft.identity.broker1.

...intuneme status shows that the broker proxy is not running:

$ intuneme status
Root:    /home/myuser/.local/share/intuneme
Rootfs:  /home/myuser/.local/share/intuneme/rootfs
Machine: intuneme
Container: running
Broker proxy: not running

I'm not sure if the broker-proxy is supposed to be running at this point, or triggered by dbus. In any case, if I attempt to start it (as it says it is not running), I get this message:

$ intuneme broker-proxy
          
   ERROR  
          
  Bus name com.microsoft.identity.broker1 already owned.                                                              

Passing --verbose does not show any more information:

$ intuneme --verbose broker-proxy
          
   ERROR  
          
  Bus name com.microsoft.identity.broker1 already owned.                                                              

Just as an experiment, I did an intuneme stop...

$ intuneme stop
  Broker proxy stopped.
  Stopping container...
  Container stopped.

...then an intuneme broker-proxy, just in case intuneme start was doing something with broker-proxy:

$ intuneme broker-proxy
          
   ERROR  
          
  Dial container bus at unix:path=/home/myuser/.local/share/intuneme/runtime/bus: dial unix                              
  /home/myuser/.local/share/intuneme/runtime/bus: connect: connection refused.                                           

...but it looks like this isn't the correct way to use broker-proxy.

Am I doing this right?

[bketelsen]

That sounds like you already have identity broker running on the host.

[bketelsen]

— Automated by Yeti —

Implementation Plan

Now I have a complete picture. Here's the implementation plan:

---

Implementation Plan: Issue #69 — broker-proxy "Bus name already owned"

Root Cause Analysis

There are three interacting bugs:

1. intuneme start doesn't detect proxy launch failure. It runs setsid intuneme broker-proxy in background, sleeps 2 seconds, then unconditionally prints "Container and broker proxy running." If the proxy crashes (e.g., bus name already taken), start never notices.

2. intuneme status only checks the PID file. If the proxy was started by D-Bus activation (without --root), or if a completely different process (e.g., a host-installed microsoft-identity-broker) owns the bus name, the PID file check misses it.

3. The "already owned" error gives no diagnostic info. It doesn't say which process owns the name, so the user can't tell if it's a stale intuneme proxy, a D-Bus-activated instance, or a different broker entirely.

4. D-Bus service file omits --root. DBusServiceFileContent() generates Exec=<path> broker-proxy without --root <root>. A D-Bus-activated instance uses the default root, which may differ from what intuneme start --root used, causing PID file mismatch.

Files to Change

File	What
internal/broker/proxy.go	Add D-Bus name-owner lookup; improve "already owned" error
cmd/start.go	Verify proxy actually started; handle pre-existing name owner
cmd/status.go	Supplement PID check with D-Bus name ownership query
cmd/config.go	Pass root to DBusServiceFileContent
internal/broker/proxy_test.go	Tests for new helper functions

Changes in Detail

1. internal/broker/proxy.go — Add NameOwnerPID() helper and improve error

Add a new exported function:

// NameOwnerPID connects to the host session bus and returns the PID of the
// process that currently owns the broker bus name, or 0 if unowned.
func NameOwnerPID() (pid int, owned bool, err error)

Implementation: connect to session bus, call org.freedesktop.DBus.GetNameOwner(BusName). If owned, call org.freedesktop.DBus.GetConnectionUnixProcessID on the owner's unique name to get the PID. This is standard D-Bus introspection — no privileges needed.

In Run(), when RequestName fails with non-primary-owner, call NameOwnerPID() and include the owning PID in the error message. Also attempt to read /proc/<pid>/comm or /proc/<pid>/cmdline to name the process:

bus name com.microsoft.identity.broker1 already owned by PID 12345 (microsoft-identity-broker)

Also update DBusServiceFileContent to accept an optional root parameter:

func DBusServiceFileContent(execPath, root string) string

When root is non-empty, emit Exec=<path> broker-proxy --root <root>.

2. cmd/start.go — Verify proxy startup, handle pre-existing owner

Before launching the proxy (after session bus is ready, around line 188): call broker.NameOwnerPID(). If the name is already owned:

• Check if the owning PID is an intuneme broker-proxy (read /proc/<pid>/cmdline). If so, adopt it: write/update the PID file and skip launching a new one. Print a message like "Broker proxy already running (PID 12345, D-Bus activated)."
• If owned by a different process, return a clear error: "Bus name com.microsoft.identity.broker1 is already owned by PID 12345 (microsoft-identity-broker). Disable the host broker or run 'intuneme config broker-proxy disable'."

After launching the proxy (replace the time.Sleep(2 * time.Second) at line 198): poll for up to 5 seconds, checking either the PID file or NameOwnerPID(). If neither confirms the proxy is running after the timeout, read stderr from the background process (if available) and return an error instead of falsely reporting success.

3. cmd/status.go — Supplement PID check with D-Bus query

When cfg.BrokerProxy is true and IsRunningByPIDFile returns false (lines 51-55), add a fallback: call broker.NameOwnerPID(). This distinguishes three states:

• PID file valid + process alive → running (PID 12345)
• PID file missing/stale but D-Bus name owned → running (PID 12345, not managed) — the proxy is working but wasn't started by intuneme start
• Neither → not running

This directly fixes the user's reported symptom where status showed "not running" even though the proxy was actually functioning.

4. cmd/config.go — Pass root to service file generator

In brokerProxyEnableCmd (line 53), pass root to DBusServiceFileContent:

content := broker.DBusServiceFileContent(execPath, root)

This ensures D-Bus-activated instances use the same root directory, so their PID file ends up where status and stop look for it.

5. internal/broker/proxy_test.go — Test new helpers

Add unit tests for:

• NameOwnerPID() when no owner (returns 0, false, nil)
• DBusServiceFileContent with and without root
• The process-name-from-PID logic (can test the /proc reading in isolation)

Note: Testing NameOwnerPID() when a name is owned requires a running D-Bus session, so this should be a build-tag-gated integration test or tested via the existing proxy test infrastructure.

Suggested Order of Implementation

1. internal/broker/proxy.go — Add NameOwnerPID() and update DBusServiceFileContent signature. These are the building blocks everything else depends on.
2. internal/broker/proxy_test.go — Test the new helpers.
3. cmd/config.go — Update call to DBusServiceFileContent (small, mechanical).
4. cmd/start.go — Add pre-launch ownership check and post-launch verification.
5. cmd/status.go — Add D-Bus fallback to status reporting.
6. internal/broker/proxy.go (Run) — Improve the "already owned" error message last, since it's the least critical fix.

Potential Risks and Edge Cases

• No D-Bus session available. NameOwnerPID() connects to the host session bus. If $DBUS_SESSION_BUS_ADDRESS is unset (e.g., SSH without forwarding), the connection will fail. The helpers should return a clean error, and callers should degrade gracefully (fall back to PID-file-only behavior) rather than crashing.

• PID reuse. Between writing the PID file and checking it, the process could die and the PID could be reused by an unrelated process. The D-Bus ownership check is the authoritative source — the PID file is a convenience. The new code should prefer the D-Bus check when both are available.

• Race between NameOwnerPID check and proxy launch. A narrow window exists where another process could claim the name between the pre-launch check and the proxy's RequestName. This is acceptable — the proxy will still fail with a clear error, and the post-launch verification will catch it.

• /proc availability. Reading /proc/<pid>/cmdline to identify the owning process assumes procfs is mounted. This is universal on Linux but should have a fallback (just show the PID without a process name).

• Existing D-Bus service files. Users who already ran intuneme config broker-proxy enable will have service files without --root. They need to re-run enable to pick up the fix. The intuneme start command could detect the stale file and warn, but this is optional — the pre-launch ownership check covers the failure mode.