Merge pull request 'Tray applets as modules: openrazer, polychromatic, forticlient, nm-applet' (#60) from feat/tray-applets into main

modules/blueman/cmd/blueman-tools/copies_test.go

@@ -0,0 +1,37 @@
+package main
+
+// The desktop applications whose bundles carry desktop.go. Each builds alone, so each has its own copy;
+// this test, itself one of the copied files, holds them to one text wherever the siblings are present.
+
+import (
+	"bytes"
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+var carriers = []string{"blueman", "forticlient", "nextcloud-client", "nm-applet", "openrazer", "polychromatic", "slack"}
+
+func TestEveryDesktopApplicationCarriesTheSameCopy(t *testing.T) {
+	compared := 0
+	for _, module := range carriers {
+		dir := filepath.Join("..", "..", "..", module, "cmd", module+"-tools")
+		if _, err := os.Stat(dir); err != nil {
+			continue
+		}
+		for _, f := range []string{"desktop.go", "desktop_test.go", "copies_test.go"} {
+			mine, err := os.ReadFile(f)
+			if err != nil {
+				t.Fatal(err)
+			}
+			theirs, err := os.ReadFile(filepath.Join(dir, f))
+			if err != nil || !bytes.Equal(mine, theirs) {
+				t.Errorf("%s's copy of %s differs from this one: change every copy together", module, f)
+			}
+		}
+		compared++
+	}
+	if compared == 0 {
+		t.Log("no sibling copies beside this module")
+	}
+}

modules/blueman/cmd/blueman-tools/desktop.go

@@ -1,8 +1,8 @@
 package main
 
-// desktop.go is the same file in the nextcloud-client, blueman and slack bundles: a
-// tray application of the operator's graphical session, seen from the node's tool runtime (novox/hq
-// ADR 0208).
+// desktop.go is the same file in every desktop application's bundle (copies_test.go names them and
+// holds them to one text): a tray application of the operator's graphical session, seen from the
+// node's tool runtime (novox/hq ADR 0208).
 //
 // The runtime is a system service running as the operator account (ADR 0175): it has the account's
 // uid and none of the session's environment. A tool that starts something on the desktop finds the
@@ -252,6 +252,22 @@ func (m *Machine) procs(comm string) []Proc {
 	return out
 }
 
+// procsOf are the account's processes named comm whose program is word. The kernel keeps 15
+// characters of a command name, so a longer name can share them with another program's: this bundle's
+// own binary among them (polychromatic-tools and polychromatic-tray-applet are both polychromatic-t).
+// The program is the first word of the command line, or the second for a script run by its
+// interpreter. An empty word keeps every process named comm.
+func (m *Machine) procsOf(comm, word string) []Proc {
+	var out []Proc
+	for _, p := range m.procs(comm) {
+		f := strings.Fields(p.Command)
+		if word == "" || (len(f) > 0 && filepath.Base(f[0]) == word) || (len(f) > 1 && filepath.Base(f[1]) == word) {
+			out = append(out, p)
+		}
+	}
+	return out
+}
+
 // uidOf is the real uid on a process's status, -1 when unreadable.
 func (m *Machine) uidOf(dir string) int {
 	for _, l := range strings.Split(readTrimmed(filepath.Join(dir, "status")), "\n") {
@@ -412,12 +428,19 @@ func (m *Machine) detach(s Session, unit string, argv ...string) error {
 // stop ends every process of the account named in comms: SIGTERM, then SIGKILL for what is still
 // there after grace. It answers the pids that ended and those that had to be killed.
 func (m *Machine) stop(grace time.Duration, comms ...string) (ended, killed []int) {
-	var pids []int
+	var ps []Proc
 	for _, c := range comms {
-		for _, p := range m.procs(c) {
-			if m.Kill(p.PID, syscall.SIGTERM) == nil {
-				pids = append(pids, p.PID)
-			}
+		ps = append(ps, m.procs(c)...)
+	}
+	return m.stopProcs(grace, ps)
+}
+
+// stopProcs ends the processes given, as stop does.
+func (m *Machine) stopProcs(grace time.Duration, ps []Proc) (ended, killed []int) {
+	var pids []int
+	for _, p := range ps {
+		if m.Kill(p.PID, syscall.SIGTERM) == nil {
+			pids = append(pids, p.PID)
 		}
 	}
 	alive := func() []int {
@@ -452,10 +475,13 @@ func (m *Machine) stop(grace time.Duration, comms ...string) (ended, killed []in
 }
 
 // waitFor waits up to d for a process of the account named comm, and answers what it found.
-func (m *Machine) waitFor(comm string, d time.Duration) []Proc {
+func (m *Machine) waitFor(comm string, d time.Duration) []Proc { return m.waitForOf(comm, "", d) }
+
+// waitForOf waits up to d for a process of the account named comm whose program is word (procsOf).
+func (m *Machine) waitForOf(comm, word string, d time.Duration) []Proc {
 	step := 250 * time.Millisecond
 	for waited := time.Duration(0); ; waited += step {
-		if p := m.procs(comm); len(p) > 0 || waited >= d {
+		if p := m.procsOf(comm, word); len(p) > 0 || waited >= d {
 			return p
 		}
 		m.Sleep(step)

modules/blueman/cmd/blueman-tools/desktop_test.go

@@ -1,7 +1,7 @@
 package main
 
-// The fake machine the tests run against, and the tests of desktop.go. The same in the
-// nextcloud-client, blueman and slack bundles.
+// The fake machine the tests run against, and the tests of desktop.go. The same in every desktop
+// application's bundle (copies_test.go).
 
 import (
 	"context"
@@ -113,6 +113,23 @@ func TestProcessesAreTheAccountsOwnWithWhereAndWhenTheyStarted(t *testing.T) {
 	}
 }
 
+func TestAProgramIsToldFromAnotherSharingItsCutName(t *testing.T) {
+	f := newFake(t)
+	f.proc(10, 1000, "polychromatic-t", []string{"/usr/bin/python", "/usr/bin/polychromatic-tray-applet"}, "s.scope")
+	f.proc(11, 1000, "polychromatic-t", []string{"polychromatic-tray-applet"}, "s.scope")
+	f.proc(12, 1000, "polychromatic-t", []string{"/usr/lib/mesh/polychromatic-tools"}, "s.scope")
+	if got := f.procsOf("polychromatic-t", "polychromatic-tray-applet"); len(got) != 2 || got[0].PID != 10 || got[1].PID != 11 {
+		t.Fatalf("%+v", got)
+	}
+	if got := f.procsOf("polychromatic-t", ""); len(got) != 3 {
+		t.Fatalf("%+v", got)
+	}
+	ended, _ := f.stopProcs(time.Second, f.procsOf("polychromatic-t", "polychromatic-tray-applet"))
+	if len(ended) != 2 || len(f.procs("polychromatic-t")) != 1 {
+		t.Fatalf("ended %v; the tools' own process must stay", ended)
+	}
+}
+
 func TestTheSessionIsTheWindowManagersAndNoneIsSaidPlainly(t *testing.T) {
 	f := newFake(t)
 	if _, err := f.session(); err == nil || !strings.Contains(err.Error(), "no graphical session") {

modules/cups/README.md

@@ -78,6 +78,25 @@ today), remove the unused vendor drivers, once:
 - **desktop:** `brother-mfc-l8390cdw` and `brother-mfc-l8390cdw-debug`. Keep `cnijfilter-mg4200` while
   the Canon queue is used.
 
+## The print applet: not this module's
+
+The desktop has `system-config-printer` (official, explicit, installed 2026-10-04). Its package ships
+`/etc/xdg/autostart/print-applet.desktop`, so from the desktop's next login `dex` starts
+`system-config-printer-applet`, a tray icon for print jobs and printer problems. The laptop does not
+have the package.
+
+This module does not take it:
+
+- `cups` needs no display and declares nothing graphical. The applet requires `x11-display`, and a
+  GTK package in this module would put it on any machine that prints, the laptop included, where the
+  operator never installed it.
+- The queues and the default printer are already this module's tools (`cups_printers`, `cups_queue`,
+  `cups_default`), which is most of what the applet's window offers.
+
+So the applet is left as found on the desktop, started by its package's entry. If it is wanted on both
+workstations, it becomes a `system-config-printer` desktop module of its own, beside `blueman` and
+`nm-applet`, requiring `x11-display`. If not, removing the package on the desktop ends it.
+
 ## Leaves as found
 
 The queues and their PPDs, the default printer, `cups.path` (enabled by the package's preset),

modules/forticlient/README.md

@@ -0,0 +1,94 @@
+# forticlient
+
+The FortiClient VPN client on the workstations, as a module (novox/hq ADR 0208): its tray in the
+operator's session and the vendor's service behind it. It requires `x11-display`, so it is assigned
+only where a display server is held on the same machine.
+
+**This is the operator's work VPN.** Nothing of its configuration is the mesh's: no profile, no
+credential, no gateway, no certificate is declared, read, printed or stored by the module or its
+tools. The tools report running and connected state only.
+
+## Owns
+
+| what | where |
+|---|---|
+| the vendor's scheduler service, which holds the tunnel | `forticlient.service`, running and enabled |
+
+Nothing else. It holds no seat, makes no contribution and writes no file.
+
+- **The client is kept as found.** `forticlient-vpn` (7.4.3) is not in the official repositories: on
+  both workstations it is a foreign (AUR) package that repackages the vendor's build, installed
+  explicitly. The host installs from the official repositories only, so the module cannot declare it.
+  ADR 0205's pinned archive does not fit: it is a vendor binary set with a root service, a firewall
+  helper and an install script. It waits for the mesh's package repository (research 027 question 1,
+  option P2). Until then a fresh workstation installs it by hand.
+- **The service is declared, and so depended on.** `forticlient.service` is the package's unit, running
+  and enabled on both workstations. Declared running and enabled, it is held in that state, and on a
+  machine without the package the host refuses it by name (*does not exist on this machine*): loud,
+  never a silent pass. The `asus-zephyrus-g14` module does the same with its foreign daemons. The
+  module never restarts it: a change to nothing of the module's would, and nothing of the module's
+  changes.
+- **The configuration stays the operator's, and unread.** `/etc/forticlient/`, the client's database
+  under `/opt/forticlient/`, the account's FortiClient settings, the VPN profiles, saved credentials
+  and certificates are set in the client's own window. They are found (ADR 0182), and unlike any other
+  found file, the tools do not even read them.
+
+## How it starts: the vendor's autostart entry, and nothing else
+
+The tray has two processes: `fortitraylauncher`, which starts and watches `fortitray`. The package's
+install script links `/etc/xdg/autostart/Fortitray.desktop` to the package's
+`/opt/forticlient/Fortitray.desktop` (`Exec=/opt/forticlient/fortitraylauncher`). The session runs it
+once at login through the `i3` module's `dex --autostart --environment i3`. **That entry is the tray's
+one start.** The module adds no `xinitrc` slot and no `node-display-session` exec, because either would
+start it a second time. The link is the vendor's, made by its install script; the mesh does not make
+or remove it.
+
+The tunnel is not the tray's: the service's processes hold it, as root. Ending the tray leaves a
+connected tunnel connected.
+
+## Tools
+
+They are served by the node's runtime as the operator account (ADR 0175).
+
+| tool | does |
+|---|---|
+| `forticlient_status` (r) | <ul><li>the installed version, and that it is from outside the official repositories</li><li>the service: active, enabled</li><li>whether the launcher and the tray run: pid, since, and the scope or unit they run in</li><li>what starts the tray at login</li><li>connected or not, as the number of the client's tunnel interfaces that are up</li></ul> |
+| `forticlient_restart` (a) | asks the tray and its launcher to end (SIGTERM), forces them after 5 s, and starts the launcher in the operator's session as a transient user unit `mesh-forticlient-tray`, so it outlives the tools runtime. The launcher starts the tray. The service and the tunnel are not touched. Refused plainly when nobody is logged in to the desktop |
+| `forticlient_check` (r) | <ul><li>the package is installed</li><li>the service is running and enabled</li><li>exactly one start: the vendor's entry is present and not hidden by an entry of the account, and `dex` is installed</li><li>no window-manager exec</li><li>one launcher and one tray run in a desktop session</li></ul>Being connected is never a finding: that is the operator's to decide. Each finding says what to do |
+
+**What the tools never touch**, held by the tests (a fake machine carries a profile, a gateway, an
+address, a secret and a certificate where the client keeps them, and no answer may hold any of them):
+
+- no file under `/etc/forticlient` or the account's FortiClient settings is opened, and under
+  `/opt/forticlient` only the tray's autostart entry, through its link (it names the launcher and
+  nothing else);
+- the vendor's command-line client and `fortivpn` are never run, and its logs are never read;
+- a process is named by its command name only, never by its arguments;
+- *connected* is whether an interface named `fctvpn…` is up, from its flags. The interface's name
+  (it carries an identifier) and its addresses are never answered. A tunnel of a kind that brings up
+  no such interface (IPsec) is not seen, and the answer says *not connected*.
+
+## What changes when it is assigned
+
+| | laptop | desktop |
+|---|---|---|
+| package | none: `forticlient-vpn` 7.4.3.5411, explicit, foreign | the same |
+| service | none: running and enabled | the same |
+| tray | none: dex starts it from the vendor's entry, in the login session's scope | none on disk. **No tray runs now:** that session began before `dex` was installed, and the predecessor's window manager never started it. The next login is the first that starts it |
+
+## Migration (ADR 0182)
+
+Nothing is required on either machine. On the desktop, log out and in once, or run
+`forticlient_restart`, and the tray runs from its one start. `forticlient_check` then answers `ok`.
+
+## Leaves as found
+
+Everything of the client's: its configuration and database, the VPN profiles and credentials, its
+logs, `/etc/xdg/autostart/Fortitray.desktop` (the vendor's link), the package itself.
+
+## Relies on
+
+- **The package, installed by hand.** Without it the host refuses the service by name.
+- **`i3`'s `dex` line for the start**: XDG autostart has no seat. Assigned without `i3`, the tray does
+  not start. `forticlient_check` says so.
+- A display server on the same machine (`x11-display`, ADR 0208 §3).

modules/forticlient/cmd/forticlient-tools/copies_test.go

@@ -0,0 +1,37 @@
+package main
+
+// The desktop applications whose bundles carry desktop.go. Each builds alone, so each has its own copy;
+// this test, itself one of the copied files, holds them to one text wherever the siblings are present.
+
+import (
+	"bytes"
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+var carriers = []string{"blueman", "forticlient", "nextcloud-client", "nm-applet", "openrazer", "polychromatic", "slack"}
+
+func TestEveryDesktopApplicationCarriesTheSameCopy(t *testing.T) {
+	compared := 0
+	for _, module := range carriers {
+		dir := filepath.Join("..", "..", "..", module, "cmd", module+"-tools")
+		if _, err := os.Stat(dir); err != nil {
+			continue
+		}
+		for _, f := range []string{"desktop.go", "desktop_test.go", "copies_test.go"} {
+			mine, err := os.ReadFile(f)
+			if err != nil {
+				t.Fatal(err)
+			}
+			theirs, err := os.ReadFile(filepath.Join(dir, f))
+			if err != nil || !bytes.Equal(mine, theirs) {
+				t.Errorf("%s's copy of %s differs from this one: change every copy together", module, f)
+			}
+		}
+		compared++
+	}
+	if compared == 0 {
+		t.Log("no sibling copies beside this module")
+	}
+}

modules/forticlient/cmd/forticlient-tools/desktop.go

@@ -0,0 +1,601 @@
+package main
+
+// desktop.go is the same file in every desktop application's bundle (copies_test.go names them and
+// holds them to one text): a tray application of the operator's graphical session, seen from the
+// node's tool runtime (novox/hq ADR 0208).
+//
+// The runtime is a system service running as the operator account (ADR 0175): it has the account's
+// uid and none of the session's environment. A tool that starts something on the desktop finds the
+// session from a process of the account that carries DISPLAY (the window manager first), and starts
+// the program under the account's own service manager with `systemd-run --user`, never as its own
+// child: the runtime's unit is a cgroup that is emptied whenever the runtime restarts.
+//
+// Everything a tool touches goes through a Machine: its filesystem root, its commands (a Runner) and
+// its signals are injected, so the tests run against a fake /proc and a fake home.
+//
+// Bounds: one command gets at most CallTimeout (below the runtime's 30 s call limit) and is ended
+// with everything it started when it takes longer; each stream is kept to MostOutput; a file is read
+// to at most MostRead.
+
+import (
+	"bufio"
+	"bytes"
+	"context"
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"sort"
+	"strconv"
+	"strings"
+	"syscall"
+	"time"
+)
+
+// Bounds every command and read is held to.
+const (
+	CallTimeout = 10 * time.Second
+	MostOutput  = 256 << 10
+	MostRead    = 16 << 20
+)
+
+// Output is what a command did.
+type Output struct {
+	Stdout string
+	Stderr string
+	Code   int
+	// Err is why it did not run to an answer: not installed, ended on its timeout, or the spawn error.
+	Err error
+	Cut bool
+}
+
+// ErrNotInstalled and ErrTimedOut are what a Runner answers in Output.Err.
+var (
+	ErrNotInstalled = errors.New("not installed")
+	ErrTimedOut     = errors.New("timed out")
+	// ErrNoSession is answered by a tool that needs the desktop when nobody is logged in to it.
+	ErrNoSession = errors.New("no graphical session")
+)
+
+// Runner runs one command with extra environment, within the context's deadline. Tests replace it.
+type Runner func(ctx context.Context, env []string, name string, args ...string) Output
+
+// Machine is what the tools read and act on.
+type Machine struct {
+	Root    string // "" on the machine; a fake root in tests
+	Home    string // the operator's home, as the machine names it
+	UID     int
+	Run     Runner
+	Kill    func(pid int, sig syscall.Signal) error
+	Sleep   func(time.Duration)
+	Now     func() time.Time
+	Timeout time.Duration
+}
+
+// NewMachine is the machine the bundle runs on.
+func NewMachine() *Machine {
+	return &Machine{Home: operatorHome(), UID: os.Getuid(), Run: execRun, Kill: syscall.Kill,
+		Sleep: time.Sleep, Now: time.Now, Timeout: CallTimeout}
+}
+
+// operatorHome is the account's home: what the runtime was told, else the process's own.
+func operatorHome() string {
+	if h := strings.TrimSpace(os.Getenv("MESH_OPERATOR_HOME")); h != "" {
+		return h
+	}
+	h, _ := os.UserHomeDir()
+	return h
+}
+
+func (m *Machine) path(p string) string { return filepath.Join(m.Root, p) }
+
+// home is a path under the operator's home, on this machine's filesystem.
+func (m *Machine) home(rel ...string) string {
+	return filepath.Join(append([]string{m.Root, m.Home}, rel...)...)
+}
+
+// tilde shows a path under the home as ~/…, so an answer does not carry the account's name.
+func (m *Machine) tilde(p string) string {
+	if m.Home != "" && m.Home != "/" {
+		h := strings.TrimSuffix(m.Home, "/")
+		if p == h {
+			return "~"
+		}
+		if strings.HasPrefix(p, h+"/") {
+			return "~/" + strings.TrimPrefix(p, h+"/")
+		}
+	}
+	return p
+}
+
+// cmd runs a command within the machine's timeout (or a shorter one).
+func (m *Machine) cmd(timeout time.Duration, env []string, name string, args ...string) Output {
+	if timeout <= 0 || timeout > m.Timeout {
+		timeout = m.Timeout
+	}
+	ctx, cancel := context.WithTimeout(context.Background(), timeout)
+	defer cancel()
+	return m.Run(ctx, env, name, args...)
+}
+
+// failed names how a command failed, or answers nil when it ran and exited 0.
+func failed(o Output, name string, args ...string) error {
+	switch {
+	case errors.Is(o.Err, ErrNotInstalled):
+		return fmt.Errorf("%s is not installed on this machine", name)
+	case errors.Is(o.Err, ErrTimedOut):
+		return fmt.Errorf("%s gave no answer in time and was ended", name)
+	case o.Err != nil:
+		return fmt.Errorf("%s did not run: %v", name, o.Err)
+	case o.Code != 0:
+		said := strings.TrimSpace(o.Stderr)
+		if said == "" {
+			said = strings.TrimSpace(o.Stdout)
+		}
+		if said == "" {
+			said = "and said nothing"
+		}
+		return fmt.Errorf("%s %s exited %d: %s", name, strings.Join(args, " "), o.Code, tail(said, 1000))
+	}
+	return nil
+}
+
+func tail(s string, n int) string {
+	if len(s) <= n {
+		return s
+	}
+	return "…" + s[len(s)-n:]
+}
+
+type capped struct {
+	b   bytes.Buffer
+	cut bool
+}
+
+func (c *capped) Write(p []byte) (int, error) {
+	if room := MostOutput - c.b.Len(); room < len(p) {
+		if room > 0 {
+			c.b.Write(p[:room])
+		}
+		c.cut = true
+		return len(p), nil
+	}
+	return c.b.Write(p)
+}
+
+func execRun(ctx context.Context, env []string, name string, args ...string) Output {
+	path, err := exec.LookPath(name)
+	if err != nil {
+		return Output{Code: 127, Err: ErrNotInstalled}
+	}
+	cmd := exec.CommandContext(ctx, path, args...)
+	cmd.Env = append(append(os.Environ(), "LC_ALL=C"), env...)
+	// Its own process group, so that ending it on a timeout ends what it started too.
+	cmd.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
+	cmd.Cancel = func() error {
+		if cmd.Process != nil {
+			_ = syscall.Kill(-cmd.Process.Pid, syscall.SIGKILL)
+		}
+		return nil
+	}
+	cmd.WaitDelay = 2 * time.Second
+	var out, errs capped
+	cmd.Stdout, cmd.Stderr = &out, &errs
+	err = cmd.Run()
+	o := Output{Stdout: out.b.String(), Stderr: errs.b.String(), Cut: out.cut || errs.cut}
+	var exit *exec.ExitError
+	switch {
+	case err == nil:
+	case ctx.Err() == context.DeadlineExceeded:
+		o.Code, o.Err = 124, ErrTimedOut
+	case errors.As(err, &exit):
+		o.Code = exit.ExitCode()
+	default:
+		o.Code, o.Err = 127, err
+	}
+	return o
+}
+
+// readBounded reads a file to at most MostRead bytes.
+func readBounded(path string) ([]byte, error) {
+	f, err := os.Open(path)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+	return io.ReadAll(io.LimitReader(f, MostRead))
+}
+
+// Proc is one process of the account.
+type Proc struct {
+	PID     int    `json:"pid"`
+	Command string `json:"command"`
+	// StartedIn is the unit or scope it runs in: the login session's scope when the session's start
+	// (dex, the window manager) started it, a mesh-… unit when a tool restarted it.
+	StartedIn string `json:"started_in,omitempty"`
+	Since     string `json:"since,omitempty"`
+}
+
+// procs are this account's processes named comm, oldest first.
+func (m *Machine) procs(comm string) []Proc {
+	entries, err := os.ReadDir(m.path("/proc"))
+	if err != nil {
+		return nil
+	}
+	boot := m.bootTime()
+	var out []Proc
+	for _, e := range entries {
+		pid, err := strconv.Atoi(e.Name())
+		if err != nil {
+			continue
+		}
+		dir := m.path(filepath.Join("/proc", e.Name()))
+		if readTrimmed(filepath.Join(dir, "comm")) != comm || m.uidOf(dir) != m.UID {
+			continue
+		}
+		p := Proc{PID: pid, Command: strings.TrimSpace(strings.ReplaceAll(readTrimmed(filepath.Join(dir, "cmdline")), "\x00", " "))}
+		if p.Command == "" {
+			p.Command = comm
+		}
+		if cg := readTrimmed(filepath.Join(dir, "cgroup")); cg != "" {
+			line := strings.Split(cg, "\n")[0]
+			p.StartedIn = filepath.Base(line[strings.LastIndexByte(line, ':')+1:])
+		}
+		if t, ok := startOf(readTrimmed(filepath.Join(dir, "stat")), boot); ok {
+			p.Since = t.UTC().Format(time.RFC3339)
+		}
+		out = append(out, p)
+	}
+	sort.Slice(out, func(i, j int) bool { return out[i].PID < out[j].PID })
+	return out
+}
+
+// procsOf are the account's processes named comm whose program is word. The kernel keeps 15
+// characters of a command name, so a longer name can share them with another program's: this bundle's
+// own binary among them (polychromatic-tools and polychromatic-tray-applet are both polychromatic-t).
+// The program is the first word of the command line, or the second for a script run by its
+// interpreter. An empty word keeps every process named comm.
+func (m *Machine) procsOf(comm, word string) []Proc {
+	var out []Proc
+	for _, p := range m.procs(comm) {
+		f := strings.Fields(p.Command)
+		if word == "" || (len(f) > 0 && filepath.Base(f[0]) == word) || (len(f) > 1 && filepath.Base(f[1]) == word) {
+			out = append(out, p)
+		}
+	}
+	return out
+}
+
+// uidOf is the real uid on a process's status, -1 when unreadable.
+func (m *Machine) uidOf(dir string) int {
+	for _, l := range strings.Split(readTrimmed(filepath.Join(dir, "status")), "\n") {
+		if f := strings.Fields(l); len(f) > 1 && f[0] == "Uid:" {
+			if n, err := strconv.Atoi(f[1]); err == nil {
+				return n
+			}
+		}
+	}
+	return -1
+}
+
+func (m *Machine) bootTime() int64 {
+	for _, l := range strings.Split(readTrimmed(m.path("/proc/stat")), "\n") {
+		if f := strings.Fields(l); len(f) == 2 && f[0] == "btime" {
+			n, _ := strconv.ParseInt(f[1], 10, 64)
+			return n
+		}
+	}
+	return 0
+}
+
+// startOf reads a process's start from its stat line (field 22, in clock ticks of 1/100 s since boot).
+func startOf(stat string, boot int64) (time.Time, bool) {
+	i := strings.LastIndexByte(stat, ')')
+	if i < 0 || boot == 0 {
+		return time.Time{}, false
+	}
+	f := strings.Fields(stat[i+1:])
+	if len(f) < 20 {
+		return time.Time{}, false
+	}
+	ticks, err := strconv.ParseInt(f[19], 10, 64)
+	if err != nil {
+		return time.Time{}, false
+	}
+	return time.Unix(boot+ticks/100, 0), true
+}
+
+func readTrimmed(path string) string {
+	b, err := os.ReadFile(path)
+	if err != nil {
+		return ""
+	}
+	return strings.TrimSpace(string(b))
+}
+
+func exists(path string) bool {
+	_, err := os.Stat(path)
+	return err == nil
+}
+
+// Session is what a tool needs to start something on the operator's desktop.
+type Session struct {
+	Display    string `json:"display"`
+	XAuthority string `json:"xauthority,omitempty"`
+	Bus        string `json:"bus,omitempty"`
+	RuntimeDir string `json:"runtime_dir,omitempty"`
+	From       string `json:"found_in"`
+}
+
+// sessionHolders are the processes whose environment is the session's, best first.
+var sessionHolders = []string{"i3", "sway", "i3bar", "picom", "dunst", "xterm"}
+
+// session finds the account's graphical session, or ErrNoSession saying what it looked at.
+func (m *Machine) session() (Session, error) {
+	entries, _ := os.ReadDir(m.path("/proc"))
+	best, bestRank := -1, len(sessionHolders)+1
+	var env map[string]string
+	var from string
+	for _, e := range entries {
+		pid, err := strconv.Atoi(e.Name())
+		if err != nil {
+			continue
+		}
+		dir := m.path(filepath.Join("/proc", e.Name()))
+		if m.uidOf(dir) != m.UID {
+			continue
+		}
+		raw, err := os.ReadFile(filepath.Join(dir, "environ"))
+		if err != nil {
+			continue
+		}
+		vars := parseEnviron(raw)
+		if vars["DISPLAY"] == "" {
+			continue
+		}
+		comm := readTrimmed(filepath.Join(dir, "comm"))
+		rank := len(sessionHolders)
+		for i, h := range sessionHolders {
+			if h == comm {
+				rank = i
+			}
+		}
+		if rank < bestRank || (rank == bestRank && pid > best) {
+			best, bestRank, env, from = pid, rank, vars, fmt.Sprintf("process %s (pid %d)", comm, pid)
+		}
+	}
+	if env == nil {
+		return Session{}, fmt.Errorf("%w for uid %d on this machine: no process of the account carries DISPLAY. "+
+			"Is anyone logged in to the desktop?", ErrNoSession, m.UID)
+	}
+	s := Session{Display: env["DISPLAY"], XAuthority: env["XAUTHORITY"], Bus: env["DBUS_SESSION_BUS_ADDRESS"],
+		RuntimeDir: env["XDG_RUNTIME_DIR"], From: from}
+	if s.RuntimeDir == "" {
+		s.RuntimeDir = fmt.Sprintf("/run/user/%d", m.UID)
+	}
+	if s.Bus == "" && exists(m.path(filepath.Join(s.RuntimeDir, "bus"))) {
+		s.Bus = "unix:path=" + filepath.Join(s.RuntimeDir, "bus")
+	}
+	return s, nil
+}
+
+// bus is the account's session bus environment, which a logged-in account has with or without a
+// desktop: what a command needs to reach the user's service manager or a bus name.
+func (m *Machine) bus() []string {
+	runtime := fmt.Sprintf("/run/user/%d", m.UID)
+	return []string{"XDG_RUNTIME_DIR=" + runtime, "DBUS_SESSION_BUS_ADDRESS=unix:path=" + runtime + "/bus"}
+}
+
+// Env is the session's variables, for a command that draws or speaks to the desktop.
+func (s Session) Env() []string {
+	var env []string
+	for _, kv := range [][2]string{{"DISPLAY", s.Display}, {"XAUTHORITY", s.XAuthority},
+		{"DBUS_SESSION_BUS_ADDRESS", s.Bus}, {"XDG_RUNTIME_DIR", s.RuntimeDir}} {
+		if kv[1] != "" {
+			env = append(env, kv[0]+"="+kv[1])
+		}
+	}
+	return env
+}
+
+func parseEnviron(raw []byte) map[string]string {
+	env := map[string]string{}
+	for _, kv := range bytes.Split(raw, []byte{0}) {
+		if i := bytes.IndexByte(kv, '='); i > 0 {
+			env[string(kv[:i])] = string(kv[i+1:])
+		}
+	}
+	return env
+}
+
+// detach starts a long-lived program under the account's service manager, as a transient unit that
+// carries the session's display. A unit left by an earlier start under the same name is stopped
+// first, so the fixed name means at most one.
+func (m *Machine) detach(s Session, unit string, argv ...string) error {
+	_ = m.cmd(5*time.Second, s.Env(), "systemctl", "--user", "stop", unit+".service")
+	call := []string{"--user", "--collect", "--quiet", "--unit=" + unit}
+	for _, kv := range [][2]string{{"DISPLAY", s.Display}, {"XAUTHORITY", s.XAuthority}} {
+		if kv[1] != "" {
+			call = append(call, "--setenv="+kv[0]+"="+kv[1])
+		}
+	}
+	call = append(append(call, "--"), argv...)
+	return failed(m.cmd(8*time.Second, s.Env(), "systemd-run", call...), "systemd-run", call...)
+}
+
+// stop ends every process of the account named in comms: SIGTERM, then SIGKILL for what is still
+// there after grace. It answers the pids that ended and those that had to be killed.
+func (m *Machine) stop(grace time.Duration, comms ...string) (ended, killed []int) {
+	var ps []Proc
+	for _, c := range comms {
+		ps = append(ps, m.procs(c)...)
+	}
+	return m.stopProcs(grace, ps)
+}
+
+// stopProcs ends the processes given, as stop does.
+func (m *Machine) stopProcs(grace time.Duration, ps []Proc) (ended, killed []int) {
+	var pids []int
+	for _, p := range ps {
+		if m.Kill(p.PID, syscall.SIGTERM) == nil {
+			pids = append(pids, p.PID)
+		}
+	}
+	alive := func() []int {
+		var left []int
+		for _, pid := range pids {
+			if exists(m.path(filepath.Join("/proc", strconv.Itoa(pid)))) {
+				left = append(left, pid)
+			}
+		}
+		return left
+	}
+	step := 200 * time.Millisecond
+	for waited := time.Duration(0); waited < grace && len(alive()) > 0; waited += step {
+		m.Sleep(step)
+	}
+	left := alive()
+	for _, pid := range left {
+		if m.Kill(pid, syscall.SIGKILL) == nil {
+			killed = append(killed, pid)
+		}
+	}
+	gone := map[int]bool{}
+	for _, pid := range left {
+		gone[pid] = true
+	}
+	for _, pid := range pids {
+		if !gone[pid] {
+			ended = append(ended, pid)
+		}
+	}
+	return ended, killed
+}
+
+// waitFor waits up to d for a process of the account named comm, and answers what it found.
+func (m *Machine) waitFor(comm string, d time.Duration) []Proc { return m.waitForOf(comm, "", d) }
+
+// waitForOf waits up to d for a process of the account named comm whose program is word (procsOf).
+func (m *Machine) waitForOf(comm, word string, d time.Duration) []Proc {
+	step := 250 * time.Millisecond
+	for waited := time.Duration(0); ; waited += step {
+		if p := m.procsOf(comm, word); len(p) > 0 || waited >= d {
+			return p
+		}
+		m.Sleep(step)
+	}
+}
+
+// desktopEntry reads the [Desktop Entry] group of an XDG desktop file; nil when there is none.
+func desktopEntry(path string) map[string]string {
+	raw, err := readBounded(path)
+	if err != nil {
+		return nil
+	}
+	out := map[string]string{}
+	in := false
+	s := bufio.NewScanner(bytes.NewReader(raw))
+	for s.Scan() {
+		l := strings.TrimSpace(s.Text())
+		switch {
+		case strings.HasPrefix(l, "["):
+			in = l == "[Desktop Entry]"
+		case in && l != "" && !strings.HasPrefix(l, "#"):
+			if i := strings.IndexByte(l, '='); i > 0 {
+				out[strings.TrimSpace(l[:i])] = strings.TrimSpace(l[i+1:])
+			}
+		}
+	}
+	return out
+}
+
+// Autostart is what XDG autostart does with one entry: the account's file overrides the system's
+// of the same name, and Hidden=true (or the GNOME switch off) means it is not started.
+type Autostart struct {
+	Entry   string `json:"entry"`
+	From    string `json:"from"`
+	Exec    string `json:"exec,omitempty"`
+	Starts  bool   `json:"starts"`
+	Because string `json:"because,omitempty"`
+}
+
+// autostart resolves one XDG autostart entry by its file name, the account's directory first.
+func (m *Machine) autostart(name string) Autostart {
+	a := Autostart{Entry: name}
+	user := m.home(".config", "autostart", name)
+	system := m.path(filepath.Join("/etc/xdg/autostart", name))
+	var e map[string]string
+	switch {
+	case exists(user):
+		e, a.From = desktopEntry(user), m.tilde(filepath.Join(m.Home, ".config/autostart", name))
+	case exists(system):
+		e, a.From = desktopEntry(system), filepath.Join("/etc/xdg/autostart", name)
+	default:
+		a.Because = "no such entry in ~/.config/autostart or /etc/xdg/autostart"
+		return a
+	}
+	a.Exec = e["Exec"]
+	switch {
+	case strings.EqualFold(e["Hidden"], "true"):
+		a.Because = "Hidden=true"
+	case strings.EqualFold(e["X-GNOME-Autostart-enabled"], "false"):
+		a.Because = "X-GNOME-Autostart-enabled=false"
+	case a.Exec == "":
+		a.Because = "the entry has no Exec"
+	default:
+		a.Starts = true
+	}
+	return a
+}
+
+// i3Starts are the window manager's start-up lines (exec, exec_always) that run a program named
+// word, in the configuration and its config.d: a second start beside an autostart entry.
+func (m *Machine) i3Starts(word string) []string {
+	files := []string{m.home(".config", "i3", "config")}
+	more, _ := filepath.Glob(m.home(".config", "i3", "config.d", "*.conf"))
+	files = append(files, more...)
+	var out []string
+	for _, f := range files {
+		raw, err := readBounded(f)
+		if err != nil {
+			continue
+		}
+		for n, l := range strings.Split(string(raw), "\n") {
+			t := strings.TrimSpace(l)
+			if !strings.HasPrefix(t, "exec ") && !strings.HasPrefix(t, "exec_always ") {
+				continue
+			}
+			for _, w := range strings.Fields(t)[1:] {
+				if filepath.Base(strings.Trim(w, `"'`)) == word {
+					out = append(out, fmt.Sprintf("%s:%d: %s", m.tilde(strings.TrimPrefix(f, m.Root)), n+1, t))
+					break
+				}
+			}
+		}
+	}
+	return out
+}
+
+// installed asks the package manager for one package's version; "" when it is not installed.
+func (m *Machine) installed(pkg string) (string, error) {
+	o := m.cmd(0, nil, "pacman", "-Q", pkg)
+	if o.Err != nil {
+		return "", failed(o, "pacman", "-Q", pkg)
+	}
+	if o.Code != 0 {
+		return "", nil
+	}
+	f := strings.Fields(o.Stdout)
+	if len(f) < 2 {
+		return "", fmt.Errorf("pacman -Q %s answered %q", pkg, o.Stdout)
+	}
+	return f[1], nil
+}
+
+// Finding is one thing a check found wrong, and what to do about it.
+type Finding struct {
+	What string `json:"what"`
+	Do   string `json:"do,omitempty"`
+}

modules/forticlient/cmd/forticlient-tools/desktop_test.go

@@ -0,0 +1,219 @@
+package main
+
+// The fake machine the tests run against, and the tests of desktop.go. The same in every desktop
+// application's bundle (copies_test.go).
+
+import (
+	"context"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"sync"
+	"syscall"
+	"testing"
+	"time"
+)
+
+const testHome = "/home/operator"
+
+// fake is a machine with a fake root, a scripted Runner and signals that end fake processes.
+type fake struct {
+	*Machine
+	t      *testing.T
+	mu     sync.Mutex
+	calls  []string
+	answer func(name string, args []string) Output
+	// onStart is run when systemd-run starts something, to let a fake process appear.
+	onStart func(argv []string)
+	// stubborn pids ignore SIGTERM.
+	stubborn map[int]bool
+	signals  []string
+}
+
+func newFake(t *testing.T) *fake {
+	t.Helper()
+	root := t.TempDir()
+	f := &fake{t: t, stubborn: map[int]bool{}}
+	f.Machine = &Machine{Root: root, Home: testHome, UID: 1000, Timeout: CallTimeout,
+		Sleep: func(time.Duration) {}, Now: func() time.Time { return time.Unix(1_800_000_000, 0) }}
+	f.Run = func(_ context.Context, env []string, name string, args ...string) Output {
+		f.mu.Lock()
+		f.calls = append(f.calls, strings.TrimSpace(name+" "+strings.Join(args, " ")))
+		f.mu.Unlock()
+		if name == "systemd-run" && f.onStart != nil {
+			for i, a := range args {
+				if a == "--" {
+					f.onStart(args[i+1:])
+				}
+			}
+		}
+		if f.answer != nil {
+			return f.answer(name, args)
+		}
+		return Output{}
+	}
+	f.Kill = func(pid int, sig syscall.Signal) error {
+		f.signals = append(f.signals, strconv.Itoa(pid)+":"+sig.String())
+		if sig == syscall.SIGKILL || !f.stubborn[pid] {
+			return os.RemoveAll(filepath.Join(root, "proc", strconv.Itoa(pid)))
+		}
+		return nil
+	}
+	f.write("/proc/stat", "cpu 1 2 3\nbtime 1799990000\n")
+	return f
+}
+
+func (f *fake) write(path, content string) {
+	f.t.Helper()
+	p := filepath.Join(f.Root, path)
+	if err := os.MkdirAll(filepath.Dir(p), 0o755); err != nil {
+		f.t.Fatal(err)
+	}
+	if err := os.WriteFile(p, []byte(content), 0o644); err != nil {
+		f.t.Fatal(err)
+	}
+}
+
+// proc adds a process of uid with a command name, argv, cgroup and environment.
+func (f *fake) proc(pid, uid int, comm string, argv []string, cgroup string, env ...string) {
+	d := "/proc/" + strconv.Itoa(pid) + "/"
+	f.write(d+"comm", comm+"\n")
+	f.write(d+"status", "Name:\t"+comm+"\nUid:\t"+strconv.Itoa(uid)+"\t"+strconv.Itoa(uid)+"\t"+strconv.Itoa(uid)+"\t"+strconv.Itoa(uid)+"\n")
+	f.write(d+"cmdline", strings.Join(argv, "\x00")+"\x00")
+	f.write(d+"cgroup", "0::/user.slice/user-"+strconv.Itoa(uid)+".slice/"+cgroup+"\n")
+	f.write(d+"environ", strings.Join(env, "\x00")+"\x00")
+	// starttime (field 22) is 1000 ticks: 10 s after boot.
+	f.write(d+"stat", strconv.Itoa(pid)+" ("+comm+") S 1 1 1 0 -1 0 0 0 0 0 0 0 0 0 20 0 1 0 1000 0 0\n")
+}
+
+func (f *fake) desktopSession() {
+	f.proc(3700, 1000, "i3", []string{"i3"}, "session-c1.scope", "DISPLAY=:1", "XAUTHORITY="+testHome+"/.Xauthority")
+	f.write("/run/user/1000/bus", "")
+}
+
+func (f *fake) called(prefix string) bool {
+	for _, c := range f.calls {
+		if strings.HasPrefix(c, prefix) {
+			return true
+		}
+	}
+	return false
+}
+
+func TestProcessesAreTheAccountsOwnWithWhereAndWhenTheyStarted(t *testing.T) {
+	f := newFake(t)
+	f.proc(10, 1000, "worker", []string{"/usr/bin/worker", "--background"}, "session-c1.scope")
+	f.proc(11, 1001, "worker", []string{"/usr/bin/worker"}, "session-c2.scope")
+	f.proc(12, 1000, "other", []string{"other"}, "x.scope")
+	got := f.procs("worker")
+	if len(got) != 1 || got[0].PID != 10 || got[0].Command != "/usr/bin/worker --background" ||
+		got[0].StartedIn != "session-c1.scope" || got[0].Since != time.Unix(1799990010, 0).UTC().Format(time.RFC3339) {
+		t.Fatalf("%+v", got)
+	}
+}
+
+func TestAProgramIsToldFromAnotherSharingItsCutName(t *testing.T) {
+	f := newFake(t)
+	f.proc(10, 1000, "polychromatic-t", []string{"/usr/bin/python", "/usr/bin/polychromatic-tray-applet"}, "s.scope")
+	f.proc(11, 1000, "polychromatic-t", []string{"polychromatic-tray-applet"}, "s.scope")
+	f.proc(12, 1000, "polychromatic-t", []string{"/usr/lib/mesh/polychromatic-tools"}, "s.scope")
+	if got := f.procsOf("polychromatic-t", "polychromatic-tray-applet"); len(got) != 2 || got[0].PID != 10 || got[1].PID != 11 {
+		t.Fatalf("%+v", got)
+	}
+	if got := f.procsOf("polychromatic-t", ""); len(got) != 3 {
+		t.Fatalf("%+v", got)
+	}
+	ended, _ := f.stopProcs(time.Second, f.procsOf("polychromatic-t", "polychromatic-tray-applet"))
+	if len(ended) != 2 || len(f.procs("polychromatic-t")) != 1 {
+		t.Fatalf("ended %v; the tools' own process must stay", ended)
+	}
+}
+
+func TestTheSessionIsTheWindowManagersAndNoneIsSaidPlainly(t *testing.T) {
+	f := newFake(t)
+	if _, err := f.session(); err == nil || !strings.Contains(err.Error(), "no graphical session") {
+		t.Fatalf("%v", err)
+	}
+	f.proc(50, 1000, "xterm", []string{"xterm"}, "s.scope", "DISPLAY=:9")
+	f.desktopSession()
+	f.proc(60, 1001, "i3", []string{"i3"}, "s.scope", "DISPLAY=:5")
+	s, err := f.session()
+	if err != nil || s.Display != ":1" || s.XAuthority != testHome+"/.Xauthority" || s.Bus != "unix:path=/run/user/1000/bus" ||
+		!strings.Contains(s.From, "i3") {
+		t.Fatalf("%+v %v", s, err)
+	}
+}
+
+func TestStopAsksThenForcesAndDetachStartsUnderTheServiceManager(t *testing.T) {
+	f := newFake(t)
+	f.desktopSession()
+	f.proc(20, 1000, "app", []string{"app"}, "s.scope")
+	f.proc(21, 1000, "app", []string{"app"}, "s.scope")
+	f.stubborn[21] = true
+	ended, killed := f.stop(time.Second, "app")
+	if len(ended) != 1 || ended[0] != 20 || len(killed) != 1 || killed[0] != 21 {
+		t.Fatalf("ended %v killed %v (%v)", ended, killed, f.signals)
+	}
+	s, _ := f.session()
+	if err := f.detach(s, "mesh-app", "/usr/bin/app", "--background"); err != nil {
+		t.Fatal(err)
+	}
+	want := "systemd-run --user --collect --quiet --unit=mesh-app --setenv=DISPLAY=:1 --setenv=XAUTHORITY=" + testHome +
+		"/.Xauthority -- /usr/bin/app --background"
+	if !f.called("systemctl --user stop mesh-app.service") || !f.called(want) {
+		t.Fatalf("%q", f.calls)
+	}
+}
+
+func TestAnAutostartEntryOfTheAccountOverridesTheSystemsAndHiddenStartsNothing(t *testing.T) {
+	f := newFake(t)
+	if a := f.autostart("x.desktop"); a.Starts || a.Because == "" {
+		t.Fatalf("%+v", a)
+	}
+	f.write("/etc/xdg/autostart/x.desktop", "[Desktop Entry]\nExec=x-applet\n[Desktop Action y]\nExec=other\n")
+	if a := f.autostart("x.desktop"); !a.Starts || a.Exec != "x-applet" || a.From != "/etc/xdg/autostart/x.desktop" {
+		t.Fatalf("%+v", a)
+	}
+	f.write(testHome+"/.config/autostart/x.desktop", "[Desktop Entry]\nExec=x-applet\nHidden=true\n")
+	if a := f.autostart("x.desktop"); a.Starts || a.Because != "Hidden=true" || a.From != "~/.config/autostart/x.desktop" {
+		t.Fatalf("%+v", a)
+	}
+}
+
+func TestAWindowManagerStartIsFoundInTheConfigurationAndItsDropIns(t *testing.T) {
+	f := newFake(t)
+	f.write(testHome+"/.config/i3/config", "exec --no-startup-id dex --autostart --environment i3\n# exec app\nbindsym $mod+a exec app\n")
+	f.write(testHome+"/.config/i3/config.d/50-x.conf", "exec_always --no-startup-id /usr/bin/app --flag\n")
+	got := f.i3Starts("app")
+	if len(got) != 1 || got[0] != "~/.config/i3/config.d/50-x.conf:1: exec_always --no-startup-id /usr/bin/app --flag" {
+		t.Fatalf("%q", got)
+	}
+}
+
+func TestACommandThatFailsIsNamed(t *testing.T) {
+	if err := failed(Output{Code: 127, Err: ErrNotInstalled}, "dex"); err == nil || !strings.Contains(err.Error(), "dex is not installed") {
+		t.Fatal(err)
+	}
+	if err := failed(Output{Code: 1, Stderr: "nope"}, "pacman", "-Q", "x"); err == nil || !strings.Contains(err.Error(), "pacman -Q x exited 1: nope") {
+		t.Fatal(err)
+	}
+	if err := failed(Output{}, "true"); err != nil {
+		t.Fatal(err)
+	}
+}
+
+func TestTheRealRunnerBoundsTimeAndOutput(t *testing.T) {
+	ctx, cancel := context.WithTimeout(context.Background(), 200*time.Millisecond)
+	defer cancel()
+	if o := execRun(ctx, nil, "sleep", "5"); o.Err != ErrTimedOut {
+		t.Fatalf("%+v", o)
+	}
+	if o := execRun(context.Background(), nil, "no-such-program-here"); o.Err != ErrNotInstalled {
+		t.Fatalf("%+v", o)
+	}
+	o := execRun(context.Background(), nil, "head", "-c", strconv.Itoa(MostOutput+10), "/dev/zero")
+	if !o.Cut || len(o.Stdout) != MostOutput {
+		t.Fatalf("cut %v, %d bytes", o.Cut, len(o.Stdout))
+	}
+}

modules/forticlient/cmd/forticlient-tools/forticlient.go

@@ -0,0 +1,205 @@
+package main
+
+// FortiClient as the tools see it: the vendor's scheduler service, the tray and the launcher that
+// starts it, the tray's XDG autostart entry, and whether a tunnel is up. This is the operator's work
+// VPN, so the tools never read its profiles, its credentials, its gateways or its certificates: no file
+// under /etc/forticlient or the account's FortiClient settings is opened, and under /opt/forticlient
+// only the tray's autostart entry (through its link in /etc/xdg/autostart); the vendor's command-line
+// client is never run, its logs are never read, a process is named by its command name only (never its
+// arguments), and a tunnel is counted, never named or addressed.
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"time"
+)
+
+const (
+	launcherComm = "fortitraylaunch" // the kernel keeps 15 characters of fortitraylauncher
+	launcherWord = "fortitraylauncher"
+	trayComm     = "fortitray"
+	launcherBin  = "/opt/forticlient/fortitraylauncher"
+	entryName    = "Fortitray.desktop"
+	restartAs    = "mesh-forticlient-tray"
+	packageFor   = "forticlient-vpn"
+	serviceUnit  = "forticlient.service"
+	// tunnelPrefix starts the name of the interface the client brings up for a connected tunnel.
+	tunnelPrefix = "fctvpn"
+)
+
+// named keeps a process's command name and drops its arguments.
+func named(ps []Proc, comm string) []Proc {
+	out := []Proc{}
+	for _, p := range ps {
+		p.Command = comm
+		out = append(out, p)
+	}
+	return out
+}
+
+// Tunnel is whether the client holds a tunnel up: how many of its tunnel interfaces exist and are up.
+// Their names and addresses are never answered.
+type Tunnel struct {
+	Connected bool `json:"connected"`
+	Up        int  `json:"tunnels_up"`
+}
+
+func (m *Machine) tunnel() Tunnel {
+	t := Tunnel{}
+	entries, _ := os.ReadDir(m.path("/sys/class/net"))
+	for _, e := range entries {
+		if !strings.HasPrefix(e.Name(), tunnelPrefix) {
+			continue
+		}
+		flags, err := strconv.ParseUint(strings.TrimPrefix(readTrimmed(m.path(filepath.Join("/sys/class/net", e.Name(), "flags"))), "0x"), 16, 32)
+		if err == nil && flags&1 == 1 { // IFF_UP
+			t.Up++
+		}
+	}
+	t.Connected = t.Up > 0
+	return t
+}
+
+// Service is the vendor's scheduler, which holds the tunnel.
+type Service struct {
+	Active  string `json:"active"`
+	Enabled string `json:"enabled"`
+}
+
+func (m *Machine) service() Service {
+	word := func(verb string) string {
+		o := m.cmd(5*time.Second, nil, "systemctl", verb, serviceUnit)
+		if f := strings.Fields(o.Stdout); o.Err == nil && len(f) > 0 {
+			return f[0]
+		}
+		return "unknown"
+	}
+	return Service{Active: word("is-active"), Enabled: word("is-enabled")}
+}
+
+// foreign says whether the package came from outside the official repositories (pacman -Qm).
+func (m *Machine) foreign() bool {
+	o := m.cmd(0, nil, "pacman", "-Qqm", packageFor)
+	return o.Err == nil && o.Code == 0 && strings.TrimSpace(o.Stdout) == packageFor
+}
+
+// StatusAnswer is what forticlient_status answers.
+type StatusAnswer struct {
+	Installed string    `json:"installed,omitempty"`
+	Foreign   bool      `json:"outside_official_repositories"`
+	Service   Service   `json:"service"`
+	Launcher  []Proc    `json:"launcher"`
+	Tray      []Proc    `json:"tray"`
+	StartedBy Autostart `json:"started_by"`
+	Tunnel    Tunnel    `json:"tunnel"`
+}
+
+// Status reads the client's running state, and nothing of its configuration.
+func (m *Machine) Status() (StatusAnswer, error) {
+	s := StatusAnswer{Service: m.service(), Launcher: named(m.procs(launcherComm), launcherWord),
+		Tray: named(m.procs(trayComm), trayComm), StartedBy: m.autostart(entryName), Tunnel: m.tunnel()}
+	v, err := m.installed(packageFor)
+	if err != nil {
+		return s, err
+	}
+	s.Installed = v
+	if v != "" {
+		s.Foreign = m.foreign()
+	}
+	return s, nil
+}
+
+// RestartAnswer is what forticlient_restart answers.
+type RestartAnswer struct {
+	Ended   []int   `json:"ended"`
+	Killed  []int   `json:"killed,omitempty"`
+	Running []Proc  `json:"running"`
+	Session Session `json:"session"`
+	Unit    string  `json:"unit"`
+	// Tunnel is after the restart: the tray is only the client's face, the service holds the tunnel.
+	Tunnel Tunnel `json:"tunnel"`
+}
+
+// Restart ends the tray and its launcher and starts the launcher again in the operator's session,
+// under the account's service manager. The launcher starts the tray. The tunnel is the service's,
+// and is not touched.
+func (m *Machine) Restart() (RestartAnswer, error) {
+	s, err := m.session()
+	if err != nil {
+		return RestartAnswer{}, err
+	}
+	a := RestartAnswer{Session: s, Unit: restartAs + ".service"}
+	a.Ended, a.Killed = m.stop(5*time.Second, launcherComm, trayComm)
+	if err := m.detach(s, restartAs, launcherBin); err != nil {
+		return a, err
+	}
+	a.Running = named(m.waitFor(launcherComm, 4*time.Second), launcherWord)
+	a.Tunnel = m.tunnel()
+	if len(a.Running) == 0 {
+		return a, fmt.Errorf("the launcher was started as %s but no %s process appeared within 4 s",
+			a.Unit, launcherWord)
+	}
+	return a, nil
+}
+
+// CheckAnswer is what forticlient_check answers. Being connected or not is never a finding: that is
+// the operator's choice, and forticlient_status says which.
+type CheckAnswer struct {
+	OK       bool      `json:"ok"`
+	Findings []Finding `json:"findings"`
+	Starts   []string  `json:"starts"`
+}
+
+// Check verifies what the module promises and relies on: the package (found, not installed by the
+// mesh); the service running and enabled; one start for the tray (the vendor's autostart entry, which
+// the session's dex runs); and the tray running once in a desktop session.
+func (m *Machine) Check() (CheckAnswer, error) {
+	a := CheckAnswer{Findings: []Finding{}, Starts: []string{}}
+	add := func(what, do string) { a.Findings = append(a.Findings, Finding{what, do}) }
+	v, err := m.installed(packageFor)
+	if err != nil {
+		return a, err
+	}
+	if v == "" {
+		add("forticlient-vpn is not installed. It is outside the official repositories, so the mesh does not install it",
+			"install it from the AUR by hand")
+	}
+	if s := m.service(); s.Active != "active" || s.Enabled != "enabled" {
+		add(fmt.Sprintf("the service %s is %s and %s", serviceUnit, s.Active, s.Enabled),
+			"push the module, which declares it running and enabled")
+	}
+	entry := m.autostart(entryName)
+	if entry.Starts {
+		a.Starts = append(a.Starts, "XDG autostart: "+entry.From)
+		if entry.From != "/etc/xdg/autostart/"+entryName {
+			add("the account's own "+entry.From+" replaces the vendor's entry", "remove it, so the vendor's entry is the one start")
+		}
+	} else {
+		add("the tray does not start with the session ("+entry.Because+")",
+			"remove ~/.config/autostart/"+entryName+" if it hides the vendor's entry; if the vendor's is gone, reinstall forticlient-vpn, whose install links it")
+	}
+	if o := m.cmd(0, nil, "dex", "--version"); o.Err != nil {
+		add("dex, which runs the XDG autostart entries at login, is not installed", "assign the i3 module, which installs it and runs it")
+	}
+	for _, word := range []string{launcherWord, trayComm} {
+		for _, l := range m.i3Starts(word) {
+			a.Starts = append(a.Starts, "window manager: "+l)
+			add("a second start: "+l, "remove the line; the vendor's autostart entry is the tray's one start")
+		}
+	}
+	if _, err := m.session(); err == nil {
+		for _, p := range []struct{ comm, word string }{{launcherComm, launcherWord}, {trayComm, trayComm}} {
+			switch running := m.procs(p.comm); {
+			case len(running) == 0:
+				add("no "+p.word+" runs in the desktop session", "forticlient_restart")
+			case len(running) > 1:
+				add(fmt.Sprintf("%d of %s run", len(running), p.word), "forticlient_restart ends them all and starts one")
+			}
+		}
+	}
+	a.OK = len(a.Findings) == 0
+	return a, nil
+}

modules/forticlient/cmd/forticlient-tools/forticlient_test.go

@@ -0,0 +1,142 @@
+package main
+
+import (
+	"encoding/json"
+	"strings"
+	"testing"
+)
+
+// secrets are what the operator's VPN configuration holds on a real machine. The fake machine carries
+// them where the client keeps them, and no answer may.
+var secrets = []string{"vpn.example.invalid", "192.0.2.10", "s3cret-psk", "work-profile", "BEGIN CERTIFICATE", "65d16a50"}
+
+func newClient(t *testing.T, running, connected bool) *fake {
+	f := newFake(t)
+	f.write("/opt/forticlient/Fortitray.desktop", "[Desktop Entry]\nType=Application\nName=Fortitray\nExec=/opt/forticlient/fortitraylauncher\nNoDisplay=true\n")
+	f.write("/etc/xdg/autostart/"+entryName, "[Desktop Entry]\nType=Application\nName=Fortitray\nExec=/opt/forticlient/fortitraylauncher\nNoDisplay=true\n")
+	f.write("/etc/forticlient/config.db", "work-profile vpn.example.invalid 192.0.2.10 s3cret-psk\n")
+	f.write(testHome+"/.config/FortiClient/state.json", `{"gateway":"vpn.example.invalid","cert":"-----BEGIN CERTIFICATE-----"}`)
+	f.write("/sys/class/net/wlp3s0/flags", "0x1003\n")
+	if connected {
+		f.write("/sys/class/net/fctvpn65d16a50/flags", "0x1091\n")
+		f.write("/sys/class/net/fctvpn65d16a50/address", "192.0.2.10\n")
+	}
+	if running {
+		f.proc(3857, 1000, launcherComm, []string{launcherBin, "--profile=work-profile"}, "session-c1.scope")
+		f.proc(4509, 1000, trayComm, []string{"/opt/forticlient/fortitray", "--gateway", "vpn.example.invalid"}, "session-c1.scope")
+	}
+	f.answer = func(name string, args []string) Output {
+		switch {
+		case name == "pacman" && args[0] == "-Q":
+			return Output{Stdout: "forticlient-vpn 7.4.3.5411-1\n"}
+		case name == "pacman" && args[0] == "-Qqm":
+			return Output{Stdout: "forticlient-vpn\n"}
+		case name == "systemctl" && args[0] == "is-active":
+			return Output{Stdout: "active\n"}
+		case name == "systemctl" && args[0] == "is-enabled":
+			return Output{Stdout: "enabled\n"}
+		}
+		return Output{}
+	}
+	return f
+}
+
+// carries fails the test when an answer holds anything of the VPN's configuration.
+func carries(t *testing.T, answer any) {
+	t.Helper()
+	raw, _ := json.Marshal(answer)
+	for _, s := range secrets {
+		if strings.Contains(string(raw), s) {
+			t.Fatalf("the answer carries %q: %s", s, raw)
+		}
+	}
+}
+
+func TestStatusIsRunningAndConnectedStateAndNothingOfTheConfiguration(t *testing.T) {
+	f := newClient(t, true, true)
+	s, err := f.Status()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if s.Installed != "7.4.3.5411-1" || !s.Foreign || s.Service != (Service{"active", "enabled"}) || len(s.Launcher) != 1 || len(s.Tray) != 1 ||
+		!s.StartedBy.Starts || !s.Tunnel.Connected || s.Tunnel.Up != 1 {
+		t.Fatalf("%+v", s)
+	}
+	if s.Launcher[0].Command != launcherWord || s.Tray[0].Command != trayComm {
+		t.Fatalf("processes by command name only: %+v %+v", s.Launcher, s.Tray)
+	}
+	carries(t, s)
+	for _, c := range f.calls {
+		for _, never := range []string{"forticlient-cli", "fortivpn", "journalctl", "sqlite", "/etc/forticlient", "/opt/forticlient/.config"} {
+			if strings.Contains(c, never) {
+				t.Fatalf("ran %q", c)
+			}
+		}
+	}
+
+	down := newClient(t, true, false)
+	down.write("/sys/class/net/fctvpn0/flags", "0x1090\n")
+	if s, _ := down.Status(); s.Tunnel.Connected || s.Tunnel.Up != 0 {
+		t.Fatalf("an interface that is down is no tunnel: %+v", s.Tunnel)
+	}
+}
+
+func TestCheckPassesTheVendorsOneStartAndNeverJudgesTheConnection(t *testing.T) {
+	f := newClient(t, true, false)
+	f.desktopSession()
+	c, err := f.Check()
+	if err != nil || !c.OK || len(c.Starts) != 1 || c.Starts[0] != "XDG autostart: /etc/xdg/autostart/"+entryName {
+		t.Fatalf("%+v %v", c, err)
+	}
+	carries(t, c)
+
+	f.write(testHome+"/.config/i3/config", "exec --no-startup-id /opt/forticlient/fortitraylauncher\n")
+	f.write(testHome+"/.config/autostart/"+entryName, "[Desktop Entry]\nExec=/opt/forticlient/fortitraylauncher\nHidden=true\n")
+	f.proc(3858, 1000, launcherComm, []string{launcherBin}, "session-c1.scope")
+	f.answer = func(name string, args []string) Output {
+		switch name {
+		case "pacman":
+			return Output{Code: 1}
+		case "systemctl":
+			return Output{Stdout: "inactive\n", Code: 3}
+		case "dex":
+			return Output{Code: 127, Err: ErrNotInstalled}
+		}
+		return Output{}
+	}
+	c, _ = f.Check()
+	var all []string
+	for _, x := range c.Findings {
+		all = append(all, x.What)
+	}
+	got := strings.Join(all, "\n")
+	for _, want := range []string{"not installed", "forticlient.service is inactive", "does not start with the session (Hidden=true)", "dex",
+		"a second start: ~/.config/i3/config:1", "2 of fortitraylauncher run"} {
+		if !strings.Contains(got, want) {
+			t.Errorf("no finding %q in\n%s", want, got)
+		}
+	}
+	carries(t, c)
+}
+
+func TestRestartStartsTheLauncherAndLeavesTheTunnel(t *testing.T) {
+	f := newClient(t, true, true)
+	if _, err := f.Restart(); err == nil || !strings.Contains(err.Error(), "no graphical session") {
+		t.Fatalf("without a desktop: %v", err)
+	}
+	f.desktopSession()
+	f.onStart = func(argv []string) { f.proc(9100, 1000, launcherComm, argv, "app.slice/"+restartAs+".service") }
+	a, err := f.Restart()
+	if err != nil || len(a.Ended) != 2 || len(a.Running) != 1 || !a.Tunnel.Connected {
+		t.Fatalf("%+v %v", a, err)
+	}
+	if !f.called("systemd-run --user --collect --quiet --unit=" + restartAs + " --setenv=DISPLAY=:1") {
+		t.Fatalf("%q", f.calls)
+	}
+	for _, c := range f.calls {
+		if strings.Contains(c, serviceUnit) {
+			t.Fatalf("the restart touched the service: %q", c)
+		}
+	}
+	carries(t, a)
+}

modules/forticlient/cmd/forticlient-tools/main.go

@@ -0,0 +1,49 @@
+// The forticlient module's Go tools bundle (novox/hq ADR 0188, ADR 0193, ADR 0208): the FortiClient
+// VPN client's tray in the operator's session and the vendor's service behind it, served by the node's
+// runtime as the operator account. The module holds no seat, so every tool is its own. The tools
+// report running and connected state only: never a profile, a credential, a gateway or a certificate.
+package main
+
+import (
+	"fmt"
+	"os"
+
+	stdio "git.novox.be/novox/mesh-sdk/go"
+)
+
+func main() {
+	if err := stdio.Serve("", tools()); err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+}
+
+var machine = NewMachine()
+
+func tools() []stdio.Tool {
+	return []stdio.Tool{
+		{
+			Name: "forticlient_status",
+			Description: "The VPN client: the installed version and whether it came from outside the official " +
+				"repositories, the vendor's service (active, enabled), whether the tray and its launcher run " +
+				"(pid, since, scope or unit), what starts the tray at login, and whether a tunnel is up (a " +
+				"count; never a name, an address, a gateway or a profile). (r)",
+			Run: func(map[string]any) (any, error) { return machine.Status() },
+		},
+		{
+			Name: "forticlient_restart",
+			Description: "End the tray and its launcher (asked first, then forced after 5 s) and start the " +
+				"launcher again in the operator's desktop session, under the account's service manager. The " +
+				"tunnel is the service's and is not touched. Needs someone logged in to the desktop. (a)",
+			Run: func(map[string]any) (any, error) { return machine.Restart() },
+		},
+		{
+			Name: "forticlient_check",
+			Description: "Check what the module promises and relies on: the package is installed (by hand: it is " +
+				"outside the official repositories); the service runs and is enabled; the tray has exactly one " +
+				"start (the vendor's XDG autostart entry, which the session's dex runs; no window-manager exec); " +
+				"and the tray and its launcher run once in a desktop session. Being connected is not checked. (r)",
+			Run: func(map[string]any) (any, error) { return machine.Check() },
+		},
+	}
+}

modules/forticlient/cmd/forticlient-tools/manifest_test.go

@@ -0,0 +1,106 @@
+package main
+
+import (
+	"encoding/json"
+	"os"
+	"path/filepath"
+	"reflect"
+	"strings"
+	"testing"
+)
+
+// forticlient's shape (novox/hq ADR 0205, ADR 0207, ADR 0208): no package (the client is outside the
+// official repositories and kept as found), the vendor's service declared running and enabled, the X
+// display on its own machine, no start of its own (the vendor's autostart entry is the tray's one
+// start), nothing of the VPN's configuration, and the Go bundle serving exactly the listed forticlient_
+// tools.
+
+type manifest struct {
+	Module        string           `json:"module"`
+	Version       string           `json:"version"`
+	Capabilities  []string         `json:"capabilities"`
+	Requires      []string         `json:"requires"`
+	Tools         []string         `json:"tools"`
+	Resources     []map[string]any `json:"resources"`
+	Claims        []any            `json:"claims"`
+	Seats         []any            `json:"seats"`
+	Shell         []any            `json:"shell"`
+	Contributions []struct {
+		Seat    string `json:"seat"`
+		Kind    string `json:"kind"`
+		Content string `json:"content"`
+	} `json:"contributions"`
+	Environment any `json:"environment"`
+	Build       struct {
+		Artifacts []map[string]any `json:"artifacts"`
+	} `json:"build"`
+}
+
+func readManifest(t *testing.T) (manifest, string) {
+	t.Helper()
+	raw, err := os.ReadFile(filepath.Join("..", "..", "module.json"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	dec := json.NewDecoder(strings.NewReader(string(raw)))
+	dec.DisallowUnknownFields()
+	var m manifest
+	if err := dec.Decode(&m); err != nil {
+		t.Fatalf("module.json: %v", err)
+	}
+	return m, string(raw)
+}
+
+func TestTheToolsAgreeWithTheManifest(t *testing.T) {
+	m, raw := readManifest(t)
+	served := map[string]bool{}
+	for _, tool := range tools() {
+		served[tool.Name] = true
+		if !strings.HasPrefix(tool.Name, "forticlient_") || strings.TrimSpace(tool.Description) == "" {
+			t.Errorf("%s: prefixed %s and described", tool.Name, "forticlient_")
+		}
+	}
+	for _, name := range m.Tools {
+		if !served[name] {
+			t.Errorf("module.json lists %s, which the bundle does not serve", name)
+		}
+		delete(served, name)
+	}
+	for name := range served {
+		t.Errorf("the bundle serves %s, which module.json does not list", name)
+	}
+	if len(m.Build.Artifacts) != 1 {
+		t.Fatalf("%v", m.Build.Artifacts)
+	}
+	b := m.Build.Artifacts[0]
+	if b["kind"] != "bundle" || b["language"] != "go" || b["system"] != "arch" ||
+		b["from"] != "cmd/forticlient-tools" || b["binary"] != "forticlient-tools" {
+		t.Errorf("the Go tools bundle: %v", b)
+	}
+	s := strings.ToLower(raw)
+	for _, never := range []string{"/home/", "jochen", "g14", "shanks", "novox.be", "http", "password", "token"} {
+		if strings.Contains(s, never) {
+			t.Errorf("module.json names %q", never)
+		}
+	}
+}
+
+func TestItDeclaresTheServiceAndNothingOfTheConfiguration(t *testing.T) {
+	m, raw := readManifest(t)
+	if m.Module != "forticlient" || !reflect.DeepEqual(m.Requires, []string{"x11-display"}) ||
+		!reflect.DeepEqual(m.Capabilities, []string{"service-manager"}) {
+		t.Fatalf("%+v", m)
+	}
+	if len(m.Resources) != 1 || m.Resources[0]["type"] != "service" || m.Resources[0]["unit"] != serviceUnit ||
+		m.Resources[0]["state"] != "running" || m.Resources[0]["boot"] != "enabled" || m.Resources[0]["restart-on"] != nil {
+		t.Fatalf("resources: %v", m.Resources)
+	}
+	if m.Claims != nil || m.Seats != nil || m.Environment != nil || m.Shell != nil || m.Contributions != nil {
+		t.Fatal("no seat, no environment, and no second start")
+	}
+	for _, never := range []string{"/etc/forticlient", "/opt/forticlient", "autostart", "\"package\"", "vpn.", "gateway", "profile"} {
+		if strings.Contains(raw, never) {
+			t.Errorf("module.json names %s", never)
+		}
+	}
+}

modules/forticlient/go.mod

@@ -0,0 +1,5 @@
+module forticlient
+
+go 1.22
+
+require git.novox.be/novox/mesh-sdk/go v0.1.7

modules/forticlient/go.sum

@@ -0,0 +1,2 @@
+git.novox.be/novox/mesh-sdk/go v0.1.7 h1:C0sTQmtTiyYH7bnqZb7PusXnqA37gKuT7Nqjn9gG47w=
+git.novox.be/novox/mesh-sdk/go v0.1.7/go.mod h1:GFuZUElBZ9A++mxgIKo97aXXo+kV0uJ/UkbhQPPIbrY=

modules/forticlient/module.json

@@ -0,0 +1,39 @@
+{
+  "module": "forticlient",
+  "version": "1",
+  "capabilities": [
+    "service-manager"
+  ],
+  "requires": [
+    "x11-display"
+  ],
+  "tools": [
+    "forticlient_status",
+    "forticlient_restart",
+    "forticlient_check"
+  ],
+  "resources": [
+    {
+      "id": "scheduler",
+      "type": "service",
+      "unit": "forticlient.service",
+      "state": "running",
+      "boot": "enabled"
+    }
+  ],
+  "build": {
+    "artifacts": [
+      {
+        "name": "tools",
+        "kind": "bundle",
+        "language": "go",
+        "system": "arch",
+        "from": "cmd/forticlient-tools",
+        "binary": "forticlient-tools",
+        "loads": [
+          "forticlient-tools"
+        ]
+      }
+    ]
+  }
+}

modules/i3/README.md

@@ -91,6 +91,7 @@ file because each module carries them now:
 | the wallpaper key (`$mod+Shift+b`) | `feh`'s `50-feh.conf` |
 | both bars | `i3status-rust`'s `60-i3status-rust.conf` |
 | the keyring prompt (`unlock-keyring.sh`) | gone: `gnome-keyring` unlocks the keyring through PAM at login |
+| the peripherals' tray (`exec … polychromatic-tray-applet`) | `polychromatic`'s contribution to node-display-session |
 
 The theme picker (`$mod+Shift+d`) goes too. It was the predecessor's tool for its theme variables,
 and settings take its place once issue 168 closes. `$mod+Delete` (`loginctl lock-session`) stays here,
@@ -98,9 +99,9 @@ because `screen-lock` relies on it. The test `TestTheMainFileAndEveryModulesDrop
 loads this file with every catalogue module's drop-in through `i3 -C`, so no two of them bind one
 key.
 
-**Kept until their owners exist.** A marked section holds the peripherals' tray applet and the
-operator's own scripts: volume, games volume, the sessions launcher and the screenshot binding. Each
-leaves when the module that owns it is written.
+**Kept until their owners exist.** A marked section holds the operator's own scripts: volume, games
+volume, the sessions launcher and the screenshot binding. Each leaves when the module that owns it is
+written. The peripherals' tray applet left it for the `polychromatic` module.
 
 ## What it leaves found
 

modules/i3/cmd/i3-tools/manifest_test.go

@@ -127,7 +127,9 @@ func TestTheConfigurationIsTheModulesFileImprovedAndEndsWithTheDropIns(t *testin
 	for _, gone := range []string{"lxpolkit", "xdg-desktop-portal", "xrdb", "Hack Nerd Font", "refresh_i3status", "rice_set", "exec xterm",
 		"exec --no-startup-id picom", "exec --no-startup-id nm-applet", "exec --no-startup-id blueman-applet", "exec --no-startup-id nextcloud", "hal/",
 		// carried by their own modules' drop-ins: rofi, clipmenu, feh, i3status-rust, gnome-keyring
-		"rofi", "greenclip", "$mod+period", "powermenu", "theme-picker", ".fehbg", "bar {", "i3status-rs", "unlock-keyring"} {
+		"rofi", "greenclip", "$mod+period", "powermenu", "theme-picker", ".fehbg", "bar {", "i3status-rs", "unlock-keyring",
+		// the peripherals' tray: polychromatic's contribution
+		"polychromatic"} {
 		if strings.Contains(code, gone) {
 			t.Errorf("the configuration still holds %q", gone)
 		}

modules/i3/config/config

@@ -174,11 +174,9 @@ client.urgent           #900000 #900000    #ffffff #900000   #900000
 #########################################
 # Each line below belongs to something other than i3, named on its line. When that module is written
 # it contributes the line to node-display-session, and the line goes from here in the same change.
-# The launcher, the clipboard, the wallpaper, the bars and a machine model's keys already contribute
-# theirs (rofi, clipmenu, feh, i3status-rust, asus-zephyrus-g14).
-
-# the peripherals' tray (the operator's application)
-exec --no-startup-id polychromatic-tray-applet
+# The launcher, the clipboard, the wallpaper, the bars, a machine model's keys and the peripherals'
+# tray already contribute theirs (rofi, clipmenu, feh, i3status-rust, asus-zephyrus-g14,
+# polychromatic).
 
 # the operator's scripts: volume, games volume, sessions, screenshot
 bindsym XF86AudioRaiseVolume exec --no-startup-id volume-notify up
@@ -194,7 +192,8 @@ bindsym --release $ctrl+$shift+x exec --no-startup-id $XDG_CONFIG_HOME/i3/script
 ######   Other modules' lines        ####
 #########################################
 # Placed by the mesh from every other module's contribution (novox/hq ADR 0212): the launcher, the
-# clipboard, the wallpaper, the bars, a machine model's keys. Each module's under a line naming it.
+# clipboard, the wallpaper, the bars, a machine model's keys, the peripherals' tray. Each module's
+# under a line naming it.
 ${contribution:node-display-session:config}
 #########################################
 ######   Your own files              ####

modules/nextcloud-client/cmd/nextcloud-client-tools/copies_test.go

@@ -0,0 +1,37 @@
+package main
+
+// The desktop applications whose bundles carry desktop.go. Each builds alone, so each has its own copy;
+// this test, itself one of the copied files, holds them to one text wherever the siblings are present.
+
+import (
+	"bytes"
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+var carriers = []string{"blueman", "forticlient", "nextcloud-client", "nm-applet", "openrazer", "polychromatic", "slack"}
+
+func TestEveryDesktopApplicationCarriesTheSameCopy(t *testing.T) {
+	compared := 0
+	for _, module := range carriers {
+		dir := filepath.Join("..", "..", "..", module, "cmd", module+"-tools")
+		if _, err := os.Stat(dir); err != nil {
+			continue
+		}
+		for _, f := range []string{"desktop.go", "desktop_test.go", "copies_test.go"} {
+			mine, err := os.ReadFile(f)
+			if err != nil {
+				t.Fatal(err)
+			}
+			theirs, err := os.ReadFile(filepath.Join(dir, f))
+			if err != nil || !bytes.Equal(mine, theirs) {
+				t.Errorf("%s's copy of %s differs from this one: change every copy together", module, f)
+			}
+		}
+		compared++
+	}
+	if compared == 0 {
+		t.Log("no sibling copies beside this module")
+	}
+}

modules/nextcloud-client/cmd/nextcloud-client-tools/desktop.go

@@ -1,8 +1,8 @@
 package main
 
-// desktop.go is the same file in the nextcloud-client, blueman and slack bundles: a
-// tray application of the operator's graphical session, seen from the node's tool runtime (novox/hq
-// ADR 0208).
+// desktop.go is the same file in every desktop application's bundle (copies_test.go names them and
+// holds them to one text): a tray application of the operator's graphical session, seen from the
+// node's tool runtime (novox/hq ADR 0208).
 //
 // The runtime is a system service running as the operator account (ADR 0175): it has the account's
 // uid and none of the session's environment. A tool that starts something on the desktop finds the
@@ -252,6 +252,22 @@ func (m *Machine) procs(comm string) []Proc {
 	return out
 }
 
+// procsOf are the account's processes named comm whose program is word. The kernel keeps 15
+// characters of a command name, so a longer name can share them with another program's: this bundle's
+// own binary among them (polychromatic-tools and polychromatic-tray-applet are both polychromatic-t).
+// The program is the first word of the command line, or the second for a script run by its
+// interpreter. An empty word keeps every process named comm.
+func (m *Machine) procsOf(comm, word string) []Proc {
+	var out []Proc
+	for _, p := range m.procs(comm) {
+		f := strings.Fields(p.Command)
+		if word == "" || (len(f) > 0 && filepath.Base(f[0]) == word) || (len(f) > 1 && filepath.Base(f[1]) == word) {
+			out = append(out, p)
+		}
+	}
+	return out
+}
+
 // uidOf is the real uid on a process's status, -1 when unreadable.
 func (m *Machine) uidOf(dir string) int {
 	for _, l := range strings.Split(readTrimmed(filepath.Join(dir, "status")), "\n") {
@@ -412,12 +428,19 @@ func (m *Machine) detach(s Session, unit string, argv ...string) error {
 // stop ends every process of the account named in comms: SIGTERM, then SIGKILL for what is still
 // there after grace. It answers the pids that ended and those that had to be killed.
 func (m *Machine) stop(grace time.Duration, comms ...string) (ended, killed []int) {
-	var pids []int
+	var ps []Proc
 	for _, c := range comms {
-		for _, p := range m.procs(c) {
-			if m.Kill(p.PID, syscall.SIGTERM) == nil {
-				pids = append(pids, p.PID)
-			}
+		ps = append(ps, m.procs(c)...)
+	}
+	return m.stopProcs(grace, ps)
+}
+
+// stopProcs ends the processes given, as stop does.
+func (m *Machine) stopProcs(grace time.Duration, ps []Proc) (ended, killed []int) {
+	var pids []int
+	for _, p := range ps {
+		if m.Kill(p.PID, syscall.SIGTERM) == nil {
+			pids = append(pids, p.PID)
 		}
 	}
 	alive := func() []int {
@@ -452,10 +475,13 @@ func (m *Machine) stop(grace time.Duration, comms ...string) (ended, killed []in
 }
 
 // waitFor waits up to d for a process of the account named comm, and answers what it found.
-func (m *Machine) waitFor(comm string, d time.Duration) []Proc {
+func (m *Machine) waitFor(comm string, d time.Duration) []Proc { return m.waitForOf(comm, "", d) }
+
+// waitForOf waits up to d for a process of the account named comm whose program is word (procsOf).
+func (m *Machine) waitForOf(comm, word string, d time.Duration) []Proc {
 	step := 250 * time.Millisecond
 	for waited := time.Duration(0); ; waited += step {
-		if p := m.procs(comm); len(p) > 0 || waited >= d {
+		if p := m.procsOf(comm, word); len(p) > 0 || waited >= d {
 			return p
 		}
 		m.Sleep(step)

modules/nextcloud-client/cmd/nextcloud-client-tools/desktop_test.go

@@ -1,7 +1,7 @@
 package main
 
-// The fake machine the tests run against, and the tests of desktop.go. The same in the
-// nextcloud-client, blueman and slack bundles.
+// The fake machine the tests run against, and the tests of desktop.go. The same in every desktop
+// application's bundle (copies_test.go).
 
 import (
 	"context"
@@ -113,6 +113,23 @@ func TestProcessesAreTheAccountsOwnWithWhereAndWhenTheyStarted(t *testing.T) {
 	}
 }
 
+func TestAProgramIsToldFromAnotherSharingItsCutName(t *testing.T) {
+	f := newFake(t)
+	f.proc(10, 1000, "polychromatic-t", []string{"/usr/bin/python", "/usr/bin/polychromatic-tray-applet"}, "s.scope")
+	f.proc(11, 1000, "polychromatic-t", []string{"polychromatic-tray-applet"}, "s.scope")
+	f.proc(12, 1000, "polychromatic-t", []string{"/usr/lib/mesh/polychromatic-tools"}, "s.scope")
+	if got := f.procsOf("polychromatic-t", "polychromatic-tray-applet"); len(got) != 2 || got[0].PID != 10 || got[1].PID != 11 {
+		t.Fatalf("%+v", got)
+	}
+	if got := f.procsOf("polychromatic-t", ""); len(got) != 3 {
+		t.Fatalf("%+v", got)
+	}
+	ended, _ := f.stopProcs(time.Second, f.procsOf("polychromatic-t", "polychromatic-tray-applet"))
+	if len(ended) != 2 || len(f.procs("polychromatic-t")) != 1 {
+		t.Fatalf("ended %v; the tools' own process must stay", ended)
+	}
+}
+
 func TestTheSessionIsTheWindowManagersAndNoneIsSaidPlainly(t *testing.T) {
 	f := newFake(t)
 	if _, err := f.session(); err == nil || !strings.Contains(err.Error(), "no graphical session") {

modules/nm-applet/README.md

@@ -0,0 +1,78 @@
+# nm-applet
+
+NetworkManager's tray applet on the workstations, as a module (novox/hq ADR 0208). It requires
+`x11-display`, so it is assigned only where a display server is held on the same machine.
+
+## Owns
+
+| what | where |
+|---|---|
+| the applet (and, as its dependencies, the connection editor and libnma) | package `network-manager-applet`, from the official repositories |
+
+Nothing else. It holds no seat, makes no contribution and writes no file.
+
+- **No AUR.** Both workstations run the official package (`extra`), installed explicitly.
+- **NetworkManager is not this module's.** The `networkmanager` module holds the node's uplink
+  (`node-uplink`) with it, on servers as well as workstations. It declares the `networkmanager`
+  package, its one drop-in and its service. This module declares none of them (ADR 0210 §4: one
+  package, one module), and it does not declare the applet's own dependencies (`nm-connection-editor`,
+  `libnma`) either: the package brings them.
+- **Why a module of its own, and not a part of `networkmanager`:** that module runs on machines with no
+  display, where a tray applet has nothing to draw on and the package would pull in GTK. The applet is
+  a desktop piece, beside `blueman` (for `bluetooth`) in the same way.
+- **The connections stay the operator's.** The applet is NetworkManager's secret agent: it asks for a
+  network's password and can keep it in the keyring. Profiles, networks, secrets and addresses are
+  joined at the machine (the `networkmanager` module's README). The tools never ask for them.
+- **The applet's settings are found.** It keeps its switches in dconf (`org.gnome.nm-applet`): the
+  notifications it shows and whether it shows itself. The module neither sets nor resets them.
+
+## How it starts: the package's autostart entry, and nothing else
+
+The package ships `/etc/xdg/autostart/nm-applet.desktop` (`nm-applet`, `NotShowIn=KDE;GNOME;`). The
+session runs it once at login through the `i3` module's `dex --autostart --environment i3`. **That
+entry is the applet's one start.** The module adds no `xinitrc` slot and no `node-display-session`
+exec, because either would start it a second time.
+
+- **Excluded:** the window manager's `exec … nm-applet`, which the `i3` module's configuration dropped.
+
+## Tools
+
+They are served by the node's runtime as the operator account (ADR 0175).
+
+| tool | does |
+|---|---|
+| `nm_applet_status` (r) | <ul><li>whether the applet runs: pid, since, and the scope or unit it runs in</li><li>the installed version, and what starts it at login</li><li>its switches in `org.gnome.nm-applet`</li><li>NetworkManager's overall state: state, connectivity, Wi-Fi and networking on or off. Never a connection, a network, a secret or an address</li></ul> |
+| `nm_applet_restart` (a) | asks the applet to end (SIGTERM), forces it after 5 s, and starts `nm-applet` in the operator's session as a transient user unit `mesh-nm-applet`, so it outlives the tools runtime. NetworkManager and its connections are not touched; for those few seconds no secret agent answers a password prompt. Refused plainly when nobody is logged in to the desktop |
+| `nm_applet_check` (r) | <ul><li>the package is installed</li><li>exactly one start: the package's entry is present and not hidden by an entry of the account, and `dex` is installed</li><li>no window-manager exec</li><li>one applet runs in a desktop session</li><li>`NetworkManager.service` is active</li></ul>Each finding says what to do |
+
+The tools find the session's `DISPLAY` and `XAUTHORITY` from the window manager's own environment, as
+`blueman` does. Every command has a timeout and capped output. Everything runs through an injected
+runner and a fake root in the tests.
+
+## What changes when it is assigned
+
+| | laptop | desktop |
+|---|---|---|
+| package | none: `network-manager-applet` 1.36.0, explicit, from `extra` | the same |
+| start | none: dex starts the applet from the package's entry, in the login session's scope | none on disk. **The applet running now came from the predecessor's window-manager line** (`nm-applet --sm-disable`, a child of i3, since the session of 2026-10-04 16:00). That session began before the `i3` module dropped the line and installed `dex`, so the next login is the first that starts it from the entry |
+
+## Migration (ADR 0182)
+
+Nothing is required on either machine. On the desktop, log out and in once, or run
+`nm_applet_restart`, and the applet runs from its one start. `nm_applet_check` then answers `ok`.
+
+## Leaves as found
+
+- The applet's dconf settings (`/org/gnome/nm-applet/`).
+- `/etc/xdg/autostart/nm-applet.desktop`, the package's own file.
+- Every connection profile and secret.
+
+## Relies on
+
+- **The `networkmanager` module, for NetworkManager.** There is no dependency mechanism between two
+  modules that hold no seat, so nothing refuses `nm-applet` without it; `nm_applet_check` reports it.
+  `networkmanager` holds `node-uplink`, but a module cannot depend on a seat without a resource or a
+  contribution that derives it (ADR 0207, ADR 0210 §3). **Assign both.**
+- **`i3`'s `dex` line for the start**, which is equally undeclared: XDG autostart has no seat.
+  Assigned without `i3`, the applet is installed and does not start. `nm_applet_check` says so.
+- A display server on the same machine (`x11-display`, ADR 0208 §3).

modules/nm-applet/cmd/nm-applet-tools/copies_test.go

@@ -0,0 +1,37 @@
+package main
+
+// The desktop applications whose bundles carry desktop.go. Each builds alone, so each has its own copy;
+// this test, itself one of the copied files, holds them to one text wherever the siblings are present.
+
+import (
+	"bytes"
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+var carriers = []string{"blueman", "forticlient", "nextcloud-client", "nm-applet", "openrazer", "polychromatic", "slack"}
+
+func TestEveryDesktopApplicationCarriesTheSameCopy(t *testing.T) {
+	compared := 0
+	for _, module := range carriers {
+		dir := filepath.Join("..", "..", "..", module, "cmd", module+"-tools")
+		if _, err := os.Stat(dir); err != nil {
+			continue
+		}
+		for _, f := range []string{"desktop.go", "desktop_test.go", "copies_test.go"} {
+			mine, err := os.ReadFile(f)
+			if err != nil {
+				t.Fatal(err)
+			}
+			theirs, err := os.ReadFile(filepath.Join(dir, f))
+			if err != nil || !bytes.Equal(mine, theirs) {
+				t.Errorf("%s's copy of %s differs from this one: change every copy together", module, f)
+			}
+		}
+		compared++
+	}
+	if compared == 0 {
+		t.Log("no sibling copies beside this module")
+	}
+}

modules/nm-applet/cmd/nm-applet-tools/desktop.go

@@ -0,0 +1,601 @@
+package main
+
+// desktop.go is the same file in every desktop application's bundle (copies_test.go names them and
+// holds them to one text): a tray application of the operator's graphical session, seen from the
+// node's tool runtime (novox/hq ADR 0208).
+//
+// The runtime is a system service running as the operator account (ADR 0175): it has the account's
+// uid and none of the session's environment. A tool that starts something on the desktop finds the
+// session from a process of the account that carries DISPLAY (the window manager first), and starts
+// the program under the account's own service manager with `systemd-run --user`, never as its own
+// child: the runtime's unit is a cgroup that is emptied whenever the runtime restarts.
+//
+// Everything a tool touches goes through a Machine: its filesystem root, its commands (a Runner) and
+// its signals are injected, so the tests run against a fake /proc and a fake home.
+//
+// Bounds: one command gets at most CallTimeout (below the runtime's 30 s call limit) and is ended
+// with everything it started when it takes longer; each stream is kept to MostOutput; a file is read
+// to at most MostRead.
+
+import (
+	"bufio"
+	"bytes"
+	"context"
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"sort"
+	"strconv"
+	"strings"
+	"syscall"
+	"time"
+)
+
+// Bounds every command and read is held to.
+const (
+	CallTimeout = 10 * time.Second
+	MostOutput  = 256 << 10
+	MostRead    = 16 << 20
+)
+
+// Output is what a command did.
+type Output struct {
+	Stdout string
+	Stderr string
+	Code   int
+	// Err is why it did not run to an answer: not installed, ended on its timeout, or the spawn error.
+	Err error
+	Cut bool
+}
+
+// ErrNotInstalled and ErrTimedOut are what a Runner answers in Output.Err.
+var (
+	ErrNotInstalled = errors.New("not installed")
+	ErrTimedOut     = errors.New("timed out")
+	// ErrNoSession is answered by a tool that needs the desktop when nobody is logged in to it.
+	ErrNoSession = errors.New("no graphical session")
+)
+
+// Runner runs one command with extra environment, within the context's deadline. Tests replace it.
+type Runner func(ctx context.Context, env []string, name string, args ...string) Output
+
+// Machine is what the tools read and act on.
+type Machine struct {
+	Root    string // "" on the machine; a fake root in tests
+	Home    string // the operator's home, as the machine names it
+	UID     int
+	Run     Runner
+	Kill    func(pid int, sig syscall.Signal) error
+	Sleep   func(time.Duration)
+	Now     func() time.Time
+	Timeout time.Duration
+}
+
+// NewMachine is the machine the bundle runs on.
+func NewMachine() *Machine {
+	return &Machine{Home: operatorHome(), UID: os.Getuid(), Run: execRun, Kill: syscall.Kill,
+		Sleep: time.Sleep, Now: time.Now, Timeout: CallTimeout}
+}
+
+// operatorHome is the account's home: what the runtime was told, else the process's own.
+func operatorHome() string {
+	if h := strings.TrimSpace(os.Getenv("MESH_OPERATOR_HOME")); h != "" {
+		return h
+	}
+	h, _ := os.UserHomeDir()
+	return h
+}
+
+func (m *Machine) path(p string) string { return filepath.Join(m.Root, p) }
+
+// home is a path under the operator's home, on this machine's filesystem.
+func (m *Machine) home(rel ...string) string {
+	return filepath.Join(append([]string{m.Root, m.Home}, rel...)...)
+}
+
+// tilde shows a path under the home as ~/…, so an answer does not carry the account's name.
+func (m *Machine) tilde(p string) string {
+	if m.Home != "" && m.Home != "/" {
+		h := strings.TrimSuffix(m.Home, "/")
+		if p == h {
+			return "~"
+		}
+		if strings.HasPrefix(p, h+"/") {
+			return "~/" + strings.TrimPrefix(p, h+"/")
+		}
+	}
+	return p
+}
+
+// cmd runs a command within the machine's timeout (or a shorter one).
+func (m *Machine) cmd(timeout time.Duration, env []string, name string, args ...string) Output {
+	if timeout <= 0 || timeout > m.Timeout {
+		timeout = m.Timeout
+	}
+	ctx, cancel := context.WithTimeout(context.Background(), timeout)
+	defer cancel()
+	return m.Run(ctx, env, name, args...)
+}
+
+// failed names how a command failed, or answers nil when it ran and exited 0.
+func failed(o Output, name string, args ...string) error {
+	switch {
+	case errors.Is(o.Err, ErrNotInstalled):
+		return fmt.Errorf("%s is not installed on this machine", name)
+	case errors.Is(o.Err, ErrTimedOut):
+		return fmt.Errorf("%s gave no answer in time and was ended", name)
+	case o.Err != nil:
+		return fmt.Errorf("%s did not run: %v", name, o.Err)
+	case o.Code != 0:
+		said := strings.TrimSpace(o.Stderr)
+		if said == "" {
+			said = strings.TrimSpace(o.Stdout)
+		}
+		if said == "" {
+			said = "and said nothing"
+		}
+		return fmt.Errorf("%s %s exited %d: %s", name, strings.Join(args, " "), o.Code, tail(said, 1000))
+	}
+	return nil
+}
+
+func tail(s string, n int) string {
+	if len(s) <= n {
+		return s
+	}
+	return "…" + s[len(s)-n:]
+}
+
+type capped struct {
+	b   bytes.Buffer
+	cut bool
+}
+
+func (c *capped) Write(p []byte) (int, error) {
+	if room := MostOutput - c.b.Len(); room < len(p) {
+		if room > 0 {
+			c.b.Write(p[:room])
+		}
+		c.cut = true
+		return len(p), nil
+	}
+	return c.b.Write(p)
+}
+
+func execRun(ctx context.Context, env []string, name string, args ...string) Output {
+	path, err := exec.LookPath(name)
+	if err != nil {
+		return Output{Code: 127, Err: ErrNotInstalled}
+	}
+	cmd := exec.CommandContext(ctx, path, args...)
+	cmd.Env = append(append(os.Environ(), "LC_ALL=C"), env...)
+	// Its own process group, so that ending it on a timeout ends what it started too.
+	cmd.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
+	cmd.Cancel = func() error {
+		if cmd.Process != nil {
+			_ = syscall.Kill(-cmd.Process.Pid, syscall.SIGKILL)
+		}
+		return nil
+	}
+	cmd.WaitDelay = 2 * time.Second
+	var out, errs capped
+	cmd.Stdout, cmd.Stderr = &out, &errs
+	err = cmd.Run()
+	o := Output{Stdout: out.b.String(), Stderr: errs.b.String(), Cut: out.cut || errs.cut}
+	var exit *exec.ExitError
+	switch {
+	case err == nil:
+	case ctx.Err() == context.DeadlineExceeded:
+		o.Code, o.Err = 124, ErrTimedOut
+	case errors.As(err, &exit):
+		o.Code = exit.ExitCode()
+	default:
+		o.Code, o.Err = 127, err
+	}
+	return o
+}
+
+// readBounded reads a file to at most MostRead bytes.
+func readBounded(path string) ([]byte, error) {
+	f, err := os.Open(path)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+	return io.ReadAll(io.LimitReader(f, MostRead))
+}
+
+// Proc is one process of the account.
+type Proc struct {
+	PID     int    `json:"pid"`
+	Command string `json:"command"`
+	// StartedIn is the unit or scope it runs in: the login session's scope when the session's start
+	// (dex, the window manager) started it, a mesh-… unit when a tool restarted it.
+	StartedIn string `json:"started_in,omitempty"`
+	Since     string `json:"since,omitempty"`
+}
+
+// procs are this account's processes named comm, oldest first.
+func (m *Machine) procs(comm string) []Proc {
+	entries, err := os.ReadDir(m.path("/proc"))
+	if err != nil {
+		return nil
+	}
+	boot := m.bootTime()
+	var out []Proc
+	for _, e := range entries {
+		pid, err := strconv.Atoi(e.Name())
+		if err != nil {
+			continue
+		}
+		dir := m.path(filepath.Join("/proc", e.Name()))
+		if readTrimmed(filepath.Join(dir, "comm")) != comm || m.uidOf(dir) != m.UID {
+			continue
+		}
+		p := Proc{PID: pid, Command: strings.TrimSpace(strings.ReplaceAll(readTrimmed(filepath.Join(dir, "cmdline")), "\x00", " "))}
+		if p.Command == "" {
+			p.Command = comm
+		}
+		if cg := readTrimmed(filepath.Join(dir, "cgroup")); cg != "" {
+			line := strings.Split(cg, "\n")[0]
+			p.StartedIn = filepath.Base(line[strings.LastIndexByte(line, ':')+1:])
+		}
+		if t, ok := startOf(readTrimmed(filepath.Join(dir, "stat")), boot); ok {
+			p.Since = t.UTC().Format(time.RFC3339)
+		}
+		out = append(out, p)
+	}
+	sort.Slice(out, func(i, j int) bool { return out[i].PID < out[j].PID })
+	return out
+}
+
+// procsOf are the account's processes named comm whose program is word. The kernel keeps 15
+// characters of a command name, so a longer name can share them with another program's: this bundle's
+// own binary among them (polychromatic-tools and polychromatic-tray-applet are both polychromatic-t).
+// The program is the first word of the command line, or the second for a script run by its
+// interpreter. An empty word keeps every process named comm.
+func (m *Machine) procsOf(comm, word string) []Proc {
+	var out []Proc
+	for _, p := range m.procs(comm) {
+		f := strings.Fields(p.Command)
+		if word == "" || (len(f) > 0 && filepath.Base(f[0]) == word) || (len(f) > 1 && filepath.Base(f[1]) == word) {
+			out = append(out, p)
+		}
+	}
+	return out
+}
+
+// uidOf is the real uid on a process's status, -1 when unreadable.
+func (m *Machine) uidOf(dir string) int {
+	for _, l := range strings.Split(readTrimmed(filepath.Join(dir, "status")), "\n") {
+		if f := strings.Fields(l); len(f) > 1 && f[0] == "Uid:" {
+			if n, err := strconv.Atoi(f[1]); err == nil {
+				return n
+			}
+		}
+	}
+	return -1
+}
+
+func (m *Machine) bootTime() int64 {
+	for _, l := range strings.Split(readTrimmed(m.path("/proc/stat")), "\n") {
+		if f := strings.Fields(l); len(f) == 2 && f[0] == "btime" {
+			n, _ := strconv.ParseInt(f[1], 10, 64)
+			return n
+		}
+	}
+	return 0
+}
+
+// startOf reads a process's start from its stat line (field 22, in clock ticks of 1/100 s since boot).
+func startOf(stat string, boot int64) (time.Time, bool) {
+	i := strings.LastIndexByte(stat, ')')
+	if i < 0 || boot == 0 {
+		return time.Time{}, false
+	}
+	f := strings.Fields(stat[i+1:])
+	if len(f) < 20 {
+		return time.Time{}, false
+	}
+	ticks, err := strconv.ParseInt(f[19], 10, 64)
+	if err != nil {
+		return time.Time{}, false
+	}
+	return time.Unix(boot+ticks/100, 0), true
+}
+
+func readTrimmed(path string) string {
+	b, err := os.ReadFile(path)
+	if err != nil {
+		return ""
+	}
+	return strings.TrimSpace(string(b))
+}
+
+func exists(path string) bool {
+	_, err := os.Stat(path)
+	return err == nil
+}
+
+// Session is what a tool needs to start something on the operator's desktop.
+type Session struct {
+	Display    string `json:"display"`
+	XAuthority string `json:"xauthority,omitempty"`
+	Bus        string `json:"bus,omitempty"`
+	RuntimeDir string `json:"runtime_dir,omitempty"`
+	From       string `json:"found_in"`
+}
+
+// sessionHolders are the processes whose environment is the session's, best first.
+var sessionHolders = []string{"i3", "sway", "i3bar", "picom", "dunst", "xterm"}
+
+// session finds the account's graphical session, or ErrNoSession saying what it looked at.
+func (m *Machine) session() (Session, error) {
+	entries, _ := os.ReadDir(m.path("/proc"))
+	best, bestRank := -1, len(sessionHolders)+1
+	var env map[string]string
+	var from string
+	for _, e := range entries {
+		pid, err := strconv.Atoi(e.Name())
+		if err != nil {
+			continue
+		}
+		dir := m.path(filepath.Join("/proc", e.Name()))
+		if m.uidOf(dir) != m.UID {
+			continue
+		}
+		raw, err := os.ReadFile(filepath.Join(dir, "environ"))
+		if err != nil {
+			continue
+		}
+		vars := parseEnviron(raw)
+		if vars["DISPLAY"] == "" {
+			continue
+		}
+		comm := readTrimmed(filepath.Join(dir, "comm"))
+		rank := len(sessionHolders)
+		for i, h := range sessionHolders {
+			if h == comm {
+				rank = i
+			}
+		}
+		if rank < bestRank || (rank == bestRank && pid > best) {
+			best, bestRank, env, from = pid, rank, vars, fmt.Sprintf("process %s (pid %d)", comm, pid)
+		}
+	}
+	if env == nil {
+		return Session{}, fmt.Errorf("%w for uid %d on this machine: no process of the account carries DISPLAY. "+
+			"Is anyone logged in to the desktop?", ErrNoSession, m.UID)
+	}
+	s := Session{Display: env["DISPLAY"], XAuthority: env["XAUTHORITY"], Bus: env["DBUS_SESSION_BUS_ADDRESS"],
+		RuntimeDir: env["XDG_RUNTIME_DIR"], From: from}
+	if s.RuntimeDir == "" {
+		s.RuntimeDir = fmt.Sprintf("/run/user/%d", m.UID)
+	}
+	if s.Bus == "" && exists(m.path(filepath.Join(s.RuntimeDir, "bus"))) {
+		s.Bus = "unix:path=" + filepath.Join(s.RuntimeDir, "bus")
+	}
+	return s, nil
+}
+
+// bus is the account's session bus environment, which a logged-in account has with or without a
+// desktop: what a command needs to reach the user's service manager or a bus name.
+func (m *Machine) bus() []string {
+	runtime := fmt.Sprintf("/run/user/%d", m.UID)
+	return []string{"XDG_RUNTIME_DIR=" + runtime, "DBUS_SESSION_BUS_ADDRESS=unix:path=" + runtime + "/bus"}
+}
+
+// Env is the session's variables, for a command that draws or speaks to the desktop.
+func (s Session) Env() []string {
+	var env []string
+	for _, kv := range [][2]string{{"DISPLAY", s.Display}, {"XAUTHORITY", s.XAuthority},
+		{"DBUS_SESSION_BUS_ADDRESS", s.Bus}, {"XDG_RUNTIME_DIR", s.RuntimeDir}} {
+		if kv[1] != "" {
+			env = append(env, kv[0]+"="+kv[1])
+		}
+	}
+	return env
+}
+
+func parseEnviron(raw []byte) map[string]string {
+	env := map[string]string{}
+	for _, kv := range bytes.Split(raw, []byte{0}) {
+		if i := bytes.IndexByte(kv, '='); i > 0 {
+			env[string(kv[:i])] = string(kv[i+1:])
+		}
+	}
+	return env
+}
+
+// detach starts a long-lived program under the account's service manager, as a transient unit that
+// carries the session's display. A unit left by an earlier start under the same name is stopped
+// first, so the fixed name means at most one.
+func (m *Machine) detach(s Session, unit string, argv ...string) error {
+	_ = m.cmd(5*time.Second, s.Env(), "systemctl", "--user", "stop", unit+".service")
+	call := []string{"--user", "--collect", "--quiet", "--unit=" + unit}
+	for _, kv := range [][2]string{{"DISPLAY", s.Display}, {"XAUTHORITY", s.XAuthority}} {
+		if kv[1] != "" {
+			call = append(call, "--setenv="+kv[0]+"="+kv[1])
+		}
+	}
+	call = append(append(call, "--"), argv...)
+	return failed(m.cmd(8*time.Second, s.Env(), "systemd-run", call...), "systemd-run", call...)
+}
+
+// stop ends every process of the account named in comms: SIGTERM, then SIGKILL for what is still
+// there after grace. It answers the pids that ended and those that had to be killed.
+func (m *Machine) stop(grace time.Duration, comms ...string) (ended, killed []int) {
+	var ps []Proc
+	for _, c := range comms {
+		ps = append(ps, m.procs(c)...)
+	}
+	return m.stopProcs(grace, ps)
+}
+
+// stopProcs ends the processes given, as stop does.
+func (m *Machine) stopProcs(grace time.Duration, ps []Proc) (ended, killed []int) {
+	var pids []int
+	for _, p := range ps {
+		if m.Kill(p.PID, syscall.SIGTERM) == nil {
+			pids = append(pids, p.PID)
+		}
+	}
+	alive := func() []int {
+		var left []int
+		for _, pid := range pids {
+			if exists(m.path(filepath.Join("/proc", strconv.Itoa(pid)))) {
+				left = append(left, pid)
+			}
+		}
+		return left
+	}
+	step := 200 * time.Millisecond
+	for waited := time.Duration(0); waited < grace && len(alive()) > 0; waited += step {
+		m.Sleep(step)
+	}
+	left := alive()
+	for _, pid := range left {
+		if m.Kill(pid, syscall.SIGKILL) == nil {
+			killed = append(killed, pid)
+		}
+	}
+	gone := map[int]bool{}
+	for _, pid := range left {
+		gone[pid] = true
+	}
+	for _, pid := range pids {
+		if !gone[pid] {
+			ended = append(ended, pid)
+		}
+	}
+	return ended, killed
+}
+
+// waitFor waits up to d for a process of the account named comm, and answers what it found.
+func (m *Machine) waitFor(comm string, d time.Duration) []Proc { return m.waitForOf(comm, "", d) }
+
+// waitForOf waits up to d for a process of the account named comm whose program is word (procsOf).
+func (m *Machine) waitForOf(comm, word string, d time.Duration) []Proc {
+	step := 250 * time.Millisecond
+	for waited := time.Duration(0); ; waited += step {
+		if p := m.procsOf(comm, word); len(p) > 0 || waited >= d {
+			return p
+		}
+		m.Sleep(step)
+	}
+}
+
+// desktopEntry reads the [Desktop Entry] group of an XDG desktop file; nil when there is none.
+func desktopEntry(path string) map[string]string {
+	raw, err := readBounded(path)
+	if err != nil {
+		return nil
+	}
+	out := map[string]string{}
+	in := false
+	s := bufio.NewScanner(bytes.NewReader(raw))
+	for s.Scan() {
+		l := strings.TrimSpace(s.Text())
+		switch {
+		case strings.HasPrefix(l, "["):
+			in = l == "[Desktop Entry]"
+		case in && l != "" && !strings.HasPrefix(l, "#"):
+			if i := strings.IndexByte(l, '='); i > 0 {
+				out[strings.TrimSpace(l[:i])] = strings.TrimSpace(l[i+1:])
+			}
+		}
+	}
+	return out
+}
+
+// Autostart is what XDG autostart does with one entry: the account's file overrides the system's
+// of the same name, and Hidden=true (or the GNOME switch off) means it is not started.
+type Autostart struct {
+	Entry   string `json:"entry"`
+	From    string `json:"from"`
+	Exec    string `json:"exec,omitempty"`
+	Starts  bool   `json:"starts"`
+	Because string `json:"because,omitempty"`
+}
+
+// autostart resolves one XDG autostart entry by its file name, the account's directory first.
+func (m *Machine) autostart(name string) Autostart {
+	a := Autostart{Entry: name}
+	user := m.home(".config", "autostart", name)
+	system := m.path(filepath.Join("/etc/xdg/autostart", name))
+	var e map[string]string
+	switch {
+	case exists(user):
+		e, a.From = desktopEntry(user), m.tilde(filepath.Join(m.Home, ".config/autostart", name))
+	case exists(system):
+		e, a.From = desktopEntry(system), filepath.Join("/etc/xdg/autostart", name)
+	default:
+		a.Because = "no such entry in ~/.config/autostart or /etc/xdg/autostart"
+		return a
+	}
+	a.Exec = e["Exec"]
+	switch {
+	case strings.EqualFold(e["Hidden"], "true"):
+		a.Because = "Hidden=true"
+	case strings.EqualFold(e["X-GNOME-Autostart-enabled"], "false"):
+		a.Because = "X-GNOME-Autostart-enabled=false"
+	case a.Exec == "":
+		a.Because = "the entry has no Exec"
+	default:
+		a.Starts = true
+	}
+	return a
+}
+
+// i3Starts are the window manager's start-up lines (exec, exec_always) that run a program named
+// word, in the configuration and its config.d: a second start beside an autostart entry.
+func (m *Machine) i3Starts(word string) []string {
+	files := []string{m.home(".config", "i3", "config")}
+	more, _ := filepath.Glob(m.home(".config", "i3", "config.d", "*.conf"))
+	files = append(files, more...)
+	var out []string
+	for _, f := range files {
+		raw, err := readBounded(f)
+		if err != nil {
+			continue
+		}
+		for n, l := range strings.Split(string(raw), "\n") {
+			t := strings.TrimSpace(l)
+			if !strings.HasPrefix(t, "exec ") && !strings.HasPrefix(t, "exec_always ") {
+				continue
+			}
+			for _, w := range strings.Fields(t)[1:] {
+				if filepath.Base(strings.Trim(w, `"'`)) == word {
+					out = append(out, fmt.Sprintf("%s:%d: %s", m.tilde(strings.TrimPrefix(f, m.Root)), n+1, t))
+					break
+				}
+			}
+		}
+	}
+	return out
+}
+
+// installed asks the package manager for one package's version; "" when it is not installed.
+func (m *Machine) installed(pkg string) (string, error) {
+	o := m.cmd(0, nil, "pacman", "-Q", pkg)
+	if o.Err != nil {
+		return "", failed(o, "pacman", "-Q", pkg)
+	}
+	if o.Code != 0 {
+		return "", nil
+	}
+	f := strings.Fields(o.Stdout)
+	if len(f) < 2 {
+		return "", fmt.Errorf("pacman -Q %s answered %q", pkg, o.Stdout)
+	}
+	return f[1], nil
+}
+
+// Finding is one thing a check found wrong, and what to do about it.
+type Finding struct {
+	What string `json:"what"`
+	Do   string `json:"do,omitempty"`
+}

modules/nm-applet/cmd/nm-applet-tools/desktop_test.go

@@ -0,0 +1,219 @@
+package main
+
+// The fake machine the tests run against, and the tests of desktop.go. The same in every desktop
+// application's bundle (copies_test.go).
+
+import (
+	"context"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"sync"
+	"syscall"
+	"testing"
+	"time"
+)
+
+const testHome = "/home/operator"
+
+// fake is a machine with a fake root, a scripted Runner and signals that end fake processes.
+type fake struct {
+	*Machine
+	t      *testing.T
+	mu     sync.Mutex
+	calls  []string
+	answer func(name string, args []string) Output
+	// onStart is run when systemd-run starts something, to let a fake process appear.
+	onStart func(argv []string)
+	// stubborn pids ignore SIGTERM.
+	stubborn map[int]bool
+	signals  []string
+}
+
+func newFake(t *testing.T) *fake {
+	t.Helper()
+	root := t.TempDir()
+	f := &fake{t: t, stubborn: map[int]bool{}}
+	f.Machine = &Machine{Root: root, Home: testHome, UID: 1000, Timeout: CallTimeout,
+		Sleep: func(time.Duration) {}, Now: func() time.Time { return time.Unix(1_800_000_000, 0) }}
+	f.Run = func(_ context.Context, env []string, name string, args ...string) Output {
+		f.mu.Lock()
+		f.calls = append(f.calls, strings.TrimSpace(name+" "+strings.Join(args, " ")))
+		f.mu.Unlock()
+		if name == "systemd-run" && f.onStart != nil {
+			for i, a := range args {
+				if a == "--" {
+					f.onStart(args[i+1:])
+				}
+			}
+		}
+		if f.answer != nil {
+			return f.answer(name, args)
+		}
+		return Output{}
+	}
+	f.Kill = func(pid int, sig syscall.Signal) error {
+		f.signals = append(f.signals, strconv.Itoa(pid)+":"+sig.String())
+		if sig == syscall.SIGKILL || !f.stubborn[pid] {
+			return os.RemoveAll(filepath.Join(root, "proc", strconv.Itoa(pid)))
+		}
+		return nil
+	}
+	f.write("/proc/stat", "cpu 1 2 3\nbtime 1799990000\n")
+	return f
+}
+
+func (f *fake) write(path, content string) {
+	f.t.Helper()
+	p := filepath.Join(f.Root, path)
+	if err := os.MkdirAll(filepath.Dir(p), 0o755); err != nil {
+		f.t.Fatal(err)
+	}
+	if err := os.WriteFile(p, []byte(content), 0o644); err != nil {
+		f.t.Fatal(err)
+	}
+}
+
+// proc adds a process of uid with a command name, argv, cgroup and environment.
+func (f *fake) proc(pid, uid int, comm string, argv []string, cgroup string, env ...string) {
+	d := "/proc/" + strconv.Itoa(pid) + "/"
+	f.write(d+"comm", comm+"\n")
+	f.write(d+"status", "Name:\t"+comm+"\nUid:\t"+strconv.Itoa(uid)+"\t"+strconv.Itoa(uid)+"\t"+strconv.Itoa(uid)+"\t"+strconv.Itoa(uid)+"\n")
+	f.write(d+"cmdline", strings.Join(argv, "\x00")+"\x00")
+	f.write(d+"cgroup", "0::/user.slice/user-"+strconv.Itoa(uid)+".slice/"+cgroup+"\n")
+	f.write(d+"environ", strings.Join(env, "\x00")+"\x00")
+	// starttime (field 22) is 1000 ticks: 10 s after boot.
+	f.write(d+"stat", strconv.Itoa(pid)+" ("+comm+") S 1 1 1 0 -1 0 0 0 0 0 0 0 0 0 20 0 1 0 1000 0 0\n")
+}
+
+func (f *fake) desktopSession() {
+	f.proc(3700, 1000, "i3", []string{"i3"}, "session-c1.scope", "DISPLAY=:1", "XAUTHORITY="+testHome+"/.Xauthority")
+	f.write("/run/user/1000/bus", "")
+}
+
+func (f *fake) called(prefix string) bool {
+	for _, c := range f.calls {
+		if strings.HasPrefix(c, prefix) {
+			return true
+		}
+	}
+	return false
+}
+
+func TestProcessesAreTheAccountsOwnWithWhereAndWhenTheyStarted(t *testing.T) {
+	f := newFake(t)
+	f.proc(10, 1000, "worker", []string{"/usr/bin/worker", "--background"}, "session-c1.scope")
+	f.proc(11, 1001, "worker", []string{"/usr/bin/worker"}, "session-c2.scope")
+	f.proc(12, 1000, "other", []string{"other"}, "x.scope")
+	got := f.procs("worker")
+	if len(got) != 1 || got[0].PID != 10 || got[0].Command != "/usr/bin/worker --background" ||
+		got[0].StartedIn != "session-c1.scope" || got[0].Since != time.Unix(1799990010, 0).UTC().Format(time.RFC3339) {
+		t.Fatalf("%+v", got)
+	}
+}
+
+func TestAProgramIsToldFromAnotherSharingItsCutName(t *testing.T) {
+	f := newFake(t)
+	f.proc(10, 1000, "polychromatic-t", []string{"/usr/bin/python", "/usr/bin/polychromatic-tray-applet"}, "s.scope")
+	f.proc(11, 1000, "polychromatic-t", []string{"polychromatic-tray-applet"}, "s.scope")
+	f.proc(12, 1000, "polychromatic-t", []string{"/usr/lib/mesh/polychromatic-tools"}, "s.scope")
+	if got := f.procsOf("polychromatic-t", "polychromatic-tray-applet"); len(got) != 2 || got[0].PID != 10 || got[1].PID != 11 {
+		t.Fatalf("%+v", got)
+	}
+	if got := f.procsOf("polychromatic-t", ""); len(got) != 3 {
+		t.Fatalf("%+v", got)
+	}
+	ended, _ := f.stopProcs(time.Second, f.procsOf("polychromatic-t", "polychromatic-tray-applet"))
+	if len(ended) != 2 || len(f.procs("polychromatic-t")) != 1 {
+		t.Fatalf("ended %v; the tools' own process must stay", ended)
+	}
+}
+
+func TestTheSessionIsTheWindowManagersAndNoneIsSaidPlainly(t *testing.T) {
+	f := newFake(t)
+	if _, err := f.session(); err == nil || !strings.Contains(err.Error(), "no graphical session") {
+		t.Fatalf("%v", err)
+	}
+	f.proc(50, 1000, "xterm", []string{"xterm"}, "s.scope", "DISPLAY=:9")
+	f.desktopSession()
+	f.proc(60, 1001, "i3", []string{"i3"}, "s.scope", "DISPLAY=:5")
+	s, err := f.session()
+	if err != nil || s.Display != ":1" || s.XAuthority != testHome+"/.Xauthority" || s.Bus != "unix:path=/run/user/1000/bus" ||
+		!strings.Contains(s.From, "i3") {
+		t.Fatalf("%+v %v", s, err)
+	}
+}
+
+func TestStopAsksThenForcesAndDetachStartsUnderTheServiceManager(t *testing.T) {
+	f := newFake(t)
+	f.desktopSession()
+	f.proc(20, 1000, "app", []string{"app"}, "s.scope")
+	f.proc(21, 1000, "app", []string{"app"}, "s.scope")
+	f.stubborn[21] = true
+	ended, killed := f.stop(time.Second, "app")
+	if len(ended) != 1 || ended[0] != 20 || len(killed) != 1 || killed[0] != 21 {
+		t.Fatalf("ended %v killed %v (%v)", ended, killed, f.signals)
+	}
+	s, _ := f.session()
+	if err := f.detach(s, "mesh-app", "/usr/bin/app", "--background"); err != nil {
+		t.Fatal(err)
+	}
+	want := "systemd-run --user --collect --quiet --unit=mesh-app --setenv=DISPLAY=:1 --setenv=XAUTHORITY=" + testHome +
+		"/.Xauthority -- /usr/bin/app --background"
+	if !f.called("systemctl --user stop mesh-app.service") || !f.called(want) {
+		t.Fatalf("%q", f.calls)
+	}
+}
+
+func TestAnAutostartEntryOfTheAccountOverridesTheSystemsAndHiddenStartsNothing(t *testing.T) {
+	f := newFake(t)
+	if a := f.autostart("x.desktop"); a.Starts || a.Because == "" {
+		t.Fatalf("%+v", a)
+	}
+	f.write("/etc/xdg/autostart/x.desktop", "[Desktop Entry]\nExec=x-applet\n[Desktop Action y]\nExec=other\n")
+	if a := f.autostart("x.desktop"); !a.Starts || a.Exec != "x-applet" || a.From != "/etc/xdg/autostart/x.desktop" {
+		t.Fatalf("%+v", a)
+	}
+	f.write(testHome+"/.config/autostart/x.desktop", "[Desktop Entry]\nExec=x-applet\nHidden=true\n")
+	if a := f.autostart("x.desktop"); a.Starts || a.Because != "Hidden=true" || a.From != "~/.config/autostart/x.desktop" {
+		t.Fatalf("%+v", a)
+	}
+}
+
+func TestAWindowManagerStartIsFoundInTheConfigurationAndItsDropIns(t *testing.T) {
+	f := newFake(t)
+	f.write(testHome+"/.config/i3/config", "exec --no-startup-id dex --autostart --environment i3\n# exec app\nbindsym $mod+a exec app\n")
+	f.write(testHome+"/.config/i3/config.d/50-x.conf", "exec_always --no-startup-id /usr/bin/app --flag\n")
+	got := f.i3Starts("app")
+	if len(got) != 1 || got[0] != "~/.config/i3/config.d/50-x.conf:1: exec_always --no-startup-id /usr/bin/app --flag" {
+		t.Fatalf("%q", got)
+	}
+}
+
+func TestACommandThatFailsIsNamed(t *testing.T) {
+	if err := failed(Output{Code: 127, Err: ErrNotInstalled}, "dex"); err == nil || !strings.Contains(err.Error(), "dex is not installed") {
+		t.Fatal(err)
+	}
+	if err := failed(Output{Code: 1, Stderr: "nope"}, "pacman", "-Q", "x"); err == nil || !strings.Contains(err.Error(), "pacman -Q x exited 1: nope") {
+		t.Fatal(err)
+	}
+	if err := failed(Output{}, "true"); err != nil {
+		t.Fatal(err)
+	}
+}
+
+func TestTheRealRunnerBoundsTimeAndOutput(t *testing.T) {
+	ctx, cancel := context.WithTimeout(context.Background(), 200*time.Millisecond)
+	defer cancel()
+	if o := execRun(ctx, nil, "sleep", "5"); o.Err != ErrTimedOut {
+		t.Fatalf("%+v", o)
+	}
+	if o := execRun(context.Background(), nil, "no-such-program-here"); o.Err != ErrNotInstalled {
+		t.Fatalf("%+v", o)
+	}
+	o := execRun(context.Background(), nil, "head", "-c", strconv.Itoa(MostOutput+10), "/dev/zero")
+	if !o.Cut || len(o.Stdout) != MostOutput {
+		t.Fatalf("cut %v, %d bytes", o.Cut, len(o.Stdout))
+	}
+}

modules/nm-applet/cmd/nm-applet-tools/main.go

@@ -0,0 +1,48 @@
+// The nm-applet module's Go tools bundle (novox/hq ADR 0188, ADR 0193, ADR 0208): NetworkManager's
+// tray applet in the operator's session, served by the node's runtime as the operator account. The
+// module holds no seat, so every tool is its own. NetworkManager itself is the networkmanager module's.
+package main
+
+import (
+	"fmt"
+	"os"
+
+	stdio "git.novox.be/novox/mesh-sdk/go"
+)
+
+func main() {
+	if err := stdio.Serve("", tools()); err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+}
+
+var machine = NewMachine()
+
+func tools() []stdio.Tool {
+	return []stdio.Tool{
+		{
+			Name: "nm_applet_status",
+			Description: "NetworkManager's applet: whether it runs (pid, since, and the unit or session scope it " +
+				"runs in), the installed version, what starts it at login, its notification switches, and " +
+				"NetworkManager's overall state (state, connectivity, Wi-Fi and networking on or off; never a " +
+				"connection, a network, a secret or an address). (r)",
+			Run: func(map[string]any) (any, error) { return machine.Status() },
+		},
+		{
+			Name: "nm_applet_restart",
+			Description: "End the applet (asked first, then forced after 5 s) and start it again in the " +
+				"operator's desktop session, under the account's service manager. NetworkManager and its " +
+				"connections are not touched. Needs someone logged in to the desktop. (a)",
+			Run: func(map[string]any) (any, error) { return machine.Restart() },
+		},
+		{
+			Name: "nm_applet_check",
+			Description: "Check what the module promises and relies on: the package is installed; the applet has " +
+				"exactly one start (the package's XDG autostart entry, which the session's dex runs; no " +
+				"window-manager exec); it runs once in a desktop session; and NetworkManager runs (the " +
+				"networkmanager module's). Answers ok and each finding with what to do. (r)",
+			Run: func(map[string]any) (any, error) { return machine.Check() },
+		},
+	}
+}

modules/nm-applet/cmd/nm-applet-tools/manifest_test.go

@@ -0,0 +1,104 @@
+package main
+
+import (
+	"encoding/json"
+	"os"
+	"path/filepath"
+	"reflect"
+	"strings"
+	"testing"
+)
+
+// nm-applet's shape (novox/hq ADR 0208, ADR 0210): the applet's one official package, no seat, the X
+// display on its own machine, no start of its own (the package's autostart entry is the one start),
+// nothing of the networkmanager module's (its package, its configuration, its service), and the Go
+// bundle serving exactly the listed nm_applet_ tools.
+
+type manifest struct {
+	Module        string           `json:"module"`
+	Version       string           `json:"version"`
+	Capabilities  []string         `json:"capabilities"`
+	Requires      []string         `json:"requires"`
+	Tools         []string         `json:"tools"`
+	Resources     []map[string]any `json:"resources"`
+	Claims        []any            `json:"claims"`
+	Seats         []any            `json:"seats"`
+	Shell         []any            `json:"shell"`
+	Contributions []struct {
+		Seat    string `json:"seat"`
+		Kind    string `json:"kind"`
+		Content string `json:"content"`
+	} `json:"contributions"`
+	Environment any `json:"environment"`
+	Build       struct {
+		Artifacts []map[string]any `json:"artifacts"`
+	} `json:"build"`
+}
+
+func readManifest(t *testing.T) (manifest, string) {
+	t.Helper()
+	raw, err := os.ReadFile(filepath.Join("..", "..", "module.json"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	dec := json.NewDecoder(strings.NewReader(string(raw)))
+	dec.DisallowUnknownFields()
+	var m manifest
+	if err := dec.Decode(&m); err != nil {
+		t.Fatalf("module.json: %v", err)
+	}
+	return m, string(raw)
+}
+
+func TestTheToolsAgreeWithTheManifest(t *testing.T) {
+	m, raw := readManifest(t)
+	served := map[string]bool{}
+	for _, tool := range tools() {
+		served[tool.Name] = true
+		if !strings.HasPrefix(tool.Name, "nm_applet_") || strings.TrimSpace(tool.Description) == "" {
+			t.Errorf("%s: prefixed %s and described", tool.Name, "nm_applet_")
+		}
+	}
+	for _, name := range m.Tools {
+		if !served[name] {
+			t.Errorf("module.json lists %s, which the bundle does not serve", name)
+		}
+		delete(served, name)
+	}
+	for name := range served {
+		t.Errorf("the bundle serves %s, which module.json does not list", name)
+	}
+	if len(m.Build.Artifacts) != 1 {
+		t.Fatalf("%v", m.Build.Artifacts)
+	}
+	b := m.Build.Artifacts[0]
+	if b["kind"] != "bundle" || b["language"] != "go" || b["system"] != "arch" ||
+		b["from"] != "cmd/nm-applet-tools" || b["binary"] != "nm-applet-tools" {
+		t.Errorf("the Go tools bundle: %v", b)
+	}
+	s := strings.ToLower(raw)
+	for _, never := range []string{"/home/", "jochen", "g14", "shanks", "novox.be", "http", "password", "token"} {
+		if strings.Contains(s, never) {
+			t.Errorf("module.json names %q", never)
+		}
+	}
+}
+
+func TestItInstallsTheAppletAndNothingOfNetworkManager(t *testing.T) {
+	m, raw := readManifest(t)
+	if m.Module != "nm-applet" || !reflect.DeepEqual(m.Requires, []string{"x11-display"}) ||
+		!reflect.DeepEqual(m.Capabilities, []string{"package-manager"}) {
+		t.Fatalf("%+v", m)
+	}
+	if len(m.Resources) != 1 || m.Resources[0]["type"] != "package" || m.Resources[0]["package"] != packageFor {
+		t.Fatalf("resources: %v", m.Resources)
+	}
+	if m.Claims != nil || m.Seats != nil || m.Environment != nil || m.Shell != nil || m.Contributions != nil {
+		t.Fatal("no seat, no environment, and no second start")
+	}
+	for _, never := range []string{"\"networkmanager\"", "nm-connection-editor", "libnma", "/etc/NetworkManager", "autostart", "service"} {
+		if strings.Contains(raw, never) {
+			t.Errorf("module.json names %s: the stack is the networkmanager module's, the start the package's", never)
+		}
+	}
+}

modules/nm-applet/cmd/nm-applet-tools/nmapplet.go

@@ -0,0 +1,169 @@
+package main
+
+// NetworkManager's applet as the tools see it: its process, its XDG autostart entry (the package's),
+// its settings in gsettings, and NetworkManager's overall state as nmcli gives it. The applet is also
+// NetworkManager's secret agent, the program that asks for a network's password; the tools never ask
+// NetworkManager for a connection, a secret or an address. Those are joined at the machine (the
+// networkmanager module's README).
+
+import (
+	"fmt"
+	"strings"
+	"time"
+)
+
+const (
+	appletComm  = "nm-applet"
+	appletBin   = "/usr/bin/nm-applet"
+	entryName   = "nm-applet.desktop"
+	restartAs   = "mesh-nm-applet"
+	packageFor  = "network-manager-applet"
+	stackUnit   = "NetworkManager.service"
+	settingsSet = "org.gnome.nm-applet"
+)
+
+// Manager is NetworkManager's overall state: no connection, network or address.
+type Manager struct {
+	State        string `json:"state"`
+	Connectivity string `json:"connectivity"`
+	Wifi         string `json:"wifi"`
+	Networking   string `json:"networking"`
+}
+
+func (m *Machine) manager() (*Manager, error) {
+	args := []string{"-t", "-f", "STATE,CONNECTIVITY,WIFI,NETWORKING", "general"}
+	o := m.cmd(5*time.Second, nil, "nmcli", args...)
+	if err := failed(o, "nmcli", args...); err != nil {
+		return nil, err
+	}
+	f := strings.Split(strings.TrimSpace(o.Stdout), ":")
+	if len(f) != 4 {
+		return nil, fmt.Errorf("nmcli's general state is not four fields: %q", tail(o.Stdout, 200))
+	}
+	return &Manager{State: f[0], Connectivity: f[1], Wifi: f[2], Networking: f[3]}, nil
+}
+
+// settings are the applet's switches in gsettings: the notifications it shows and whether it shows
+// itself.
+func (m *Machine) settings() map[string]string {
+	out := map[string]string{}
+	o := m.cmd(5*time.Second, m.bus(), "gsettings", "list-recursively", settingsSet)
+	if o.Err != nil || o.Code != 0 {
+		return out
+	}
+	for _, l := range strings.Split(o.Stdout, "\n") {
+		f := strings.Fields(l)
+		if len(f) == 3 && f[0] == settingsSet && f[1] != "stamp" {
+			out[f[1]] = f[2]
+		}
+	}
+	return out
+}
+
+// StatusAnswer is what nm_applet_status answers.
+type StatusAnswer struct {
+	Installed  string            `json:"installed,omitempty"`
+	Applet     []Proc            `json:"applet"`
+	StartedBy  Autostart         `json:"started_by"`
+	Settings   map[string]string `json:"settings"`
+	Manager    *Manager          `json:"network_manager,omitempty"`
+	Unanswered string            `json:"unanswered,omitempty"`
+}
+
+// Status reads the applet and NetworkManager's overall state.
+func (m *Machine) Status() (StatusAnswer, error) {
+	s := StatusAnswer{Applet: m.procs(appletComm), StartedBy: m.autostart(entryName), Settings: m.settings()}
+	if s.Applet == nil {
+		s.Applet = []Proc{}
+	}
+	v, err := m.installed(packageFor)
+	if err != nil {
+		return s, err
+	}
+	s.Installed = v
+	if s.Manager, err = m.manager(); err != nil {
+		s.Unanswered = err.Error()
+	}
+	return s, nil
+}
+
+// RestartAnswer is what nm_applet_restart answers.
+type RestartAnswer struct {
+	Ended   []int   `json:"ended"`
+	Killed  []int   `json:"killed,omitempty"`
+	Running []Proc  `json:"running"`
+	Session Session `json:"session"`
+	Unit    string  `json:"unit"`
+}
+
+// Restart ends the applet and starts it again in the operator's session, under the account's service
+// manager. NetworkManager and its connections are not touched: the applet is only their face.
+func (m *Machine) Restart() (RestartAnswer, error) {
+	s, err := m.session()
+	if err != nil {
+		return RestartAnswer{}, err
+	}
+	a := RestartAnswer{Session: s, Unit: restartAs + ".service"}
+	a.Ended, a.Killed = m.stop(5*time.Second, appletComm)
+	if err := m.detach(s, restartAs, appletBin); err != nil {
+		return a, err
+	}
+	a.Running = m.waitFor(appletComm, 4*time.Second)
+	if len(a.Running) == 0 {
+		return a, fmt.Errorf("the applet was started as %s but no %s process appeared within 4 s: "+
+			"see `journalctl --user -u %s`", a.Unit, appletComm, a.Unit)
+	}
+	return a, nil
+}
+
+// CheckAnswer is what nm_applet_check answers.
+type CheckAnswer struct {
+	OK       bool      `json:"ok"`
+	Findings []Finding `json:"findings"`
+	Starts   []string  `json:"starts"`
+}
+
+// Check verifies what the module promises and relies on: the package; one start (the package's
+// autostart entry, which the session's dex runs); the applet running once in a session; and
+// NetworkManager, which is the networkmanager module's, running.
+func (m *Machine) Check() (CheckAnswer, error) {
+	a := CheckAnswer{Findings: []Finding{}, Starts: []string{}}
+	add := func(what, do string) { a.Findings = append(a.Findings, Finding{what, do}) }
+	v, err := m.installed(packageFor)
+	if err != nil {
+		return a, err
+	}
+	if v == "" {
+		add("the package "+packageFor+" is not installed", "push the module to the node")
+	}
+	entry := m.autostart(entryName)
+	if entry.Starts {
+		a.Starts = append(a.Starts, "XDG autostart: "+entry.From)
+		if entry.From != "/etc/xdg/autostart/"+entryName {
+			add("the account's own "+entry.From+" replaces the package's entry", "remove it, so the package's entry is the one start")
+		}
+	} else {
+		add("the applet does not start with the session ("+entry.Because+")", "remove ~/.config/autostart/"+entryName+" if it hides the package's entry")
+	}
+	if o := m.cmd(0, nil, "dex", "--version"); o.Err != nil {
+		add("dex, which runs the XDG autostart entries at login, is not installed", "assign the i3 module, which installs it and runs it")
+	}
+	for _, l := range m.i3Starts(appletComm) {
+		a.Starts = append(a.Starts, "window manager: "+l)
+		add("a second start: "+l, "remove the line; the package's autostart entry is the applet's one start")
+	}
+	if o := m.cmd(0, nil, "systemctl", "is-active", stackUnit); o.Err != nil || strings.TrimSpace(o.Stdout) != "active" {
+		add("NetworkManager ("+stackUnit+") is not running: the applet has nothing to show",
+			"assign the networkmanager module, which holds the node's uplink with it")
+	}
+	if _, err := m.session(); err == nil {
+		switch running := m.procs(appletComm); {
+		case len(running) == 0:
+			add("no applet runs in the desktop session", "nm_applet_restart")
+		case len(running) > 1:
+			add(fmt.Sprintf("%d applets run", len(running)), "nm_applet_restart ends them all and starts one")
+		}
+	}
+	a.OK = len(a.Findings) == 0
+	return a, nil
+}

modules/nm-applet/cmd/nm-applet-tools/nmapplet_test.go

@@ -0,0 +1,107 @@
+package main
+
+import (
+	"strings"
+	"testing"
+)
+
+func newApplet(t *testing.T, running bool) *fake {
+	f := newFake(t)
+	f.write("/etc/xdg/autostart/"+entryName, "[Desktop Entry]\nName=Network\nExec=nm-applet\nNotShowIn=KDE;GNOME;\n")
+	if running {
+		f.proc(3860, 1000, appletComm, []string{"nm-applet"}, "session-c1.scope")
+	}
+	f.answer = func(name string, args []string) Output {
+		switch {
+		case name == "pacman":
+			return Output{Stdout: "network-manager-applet 1.36.0-2\n"}
+		case name == "nmcli":
+			return Output{Stdout: "connected:full:enabled:enabled\n"}
+		case name == "gsettings":
+			return Output{Stdout: "org.gnome.nm-applet disable-connected-notifications false\norg.gnome.nm-applet stamp 0\n" +
+				"org.gnome.nm-applet show-applet true\n"}
+		case name == "systemctl":
+			return Output{Stdout: "active\n"}
+		}
+		return Output{}
+	}
+	return f
+}
+
+func TestStatusReadsTheAppletAndOnlyTheManagersOverallState(t *testing.T) {
+	f := newApplet(t, true)
+	s, err := f.Status()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if s.Installed != "1.36.0-2" || len(s.Applet) != 1 || !s.StartedBy.Starts || s.Manager == nil ||
+		*s.Manager != (Manager{"connected", "full", "enabled", "enabled"}) || len(s.Settings) != 2 || s.Settings["show-applet"] != "true" {
+		t.Fatalf("%+v", s)
+	}
+	for _, c := range f.calls {
+		for _, never := range []string{"connection", "device", "secrets", "--show-secrets", " ip"} {
+			if strings.HasPrefix(c, "nmcli") && strings.Contains(c, never) {
+				t.Fatalf("asked NetworkManager for more than its overall state: %q", c)
+			}
+		}
+	}
+	f.answer = func(name string, args []string) Output {
+		if name == "nmcli" {
+			return Output{Code: 8, Stderr: "Error: NetworkManager is not running."}
+		}
+		return Output{Stdout: "x 1\n"}
+	}
+	if s, _ := f.Status(); s.Manager != nil || !strings.Contains(s.Unanswered, "not running") {
+		t.Fatalf("%+v", s)
+	}
+}
+
+func TestCheckPassesThePackagesOneStartAndNamesEveryOther(t *testing.T) {
+	f := newApplet(t, true)
+	f.desktopSession()
+	c, err := f.Check()
+	if err != nil || !c.OK || len(c.Starts) != 1 || c.Starts[0] != "XDG autostart: /etc/xdg/autostart/"+entryName {
+		t.Fatalf("%+v %v", c, err)
+	}
+
+	f.write(testHome+"/.config/i3/config", "exec --no-startup-id nm-applet --sm-disable\n")
+	f.proc(3861, 1000, appletComm, []string{"nm-applet"}, "session-c1.scope")
+	f.answer = func(name string, args []string) Output {
+		switch name {
+		case "pacman":
+			return Output{Code: 1}
+		case "systemctl":
+			return Output{Stdout: "inactive\n", Code: 3}
+		}
+		return Output{}
+	}
+	c, _ = f.Check()
+	var all []string
+	for _, x := range c.Findings {
+		all = append(all, x.What)
+	}
+	got := strings.Join(all, "\n")
+	for _, want := range []string{"not installed", "a second start: ~/.config/i3/config:1", "NetworkManager.service", "2 applets run"} {
+		if !strings.Contains(got, want) {
+			t.Errorf("no finding %q in\n%s", want, got)
+		}
+	}
+}
+
+func TestRestartEndsTheAppletAndStartsItUnderTheServiceManager(t *testing.T) {
+	f := newApplet(t, true)
+	if _, err := f.Restart(); err == nil || !strings.Contains(err.Error(), "no graphical session") {
+		t.Fatalf("without a desktop: %v", err)
+	}
+	f.desktopSession()
+	f.onStart = func(argv []string) { f.proc(9100, 1000, appletComm, argv, "app.slice/"+restartAs+".service") }
+	a, err := f.Restart()
+	if err != nil || len(a.Ended) != 1 || len(a.Running) != 1 || a.Running[0].Command != appletBin {
+		t.Fatalf("%+v %v", a, err)
+	}
+	for _, c := range f.calls {
+		if strings.Contains(c, stackUnit) {
+			t.Fatalf("the restart touched NetworkManager: %q", c)
+		}
+	}
+}

modules/nm-applet/go.mod

@@ -0,0 +1,5 @@
+module nm-applet
+
+go 1.22
+
+require git.novox.be/novox/mesh-sdk/go v0.1.7

modules/nm-applet/go.sum

@@ -0,0 +1,2 @@
+git.novox.be/novox/mesh-sdk/go v0.1.7 h1:C0sTQmtTiyYH7bnqZb7PusXnqA37gKuT7Nqjn9gG47w=
+git.novox.be/novox/mesh-sdk/go v0.1.7/go.mod h1:GFuZUElBZ9A++mxgIKo97aXXo+kV0uJ/UkbhQPPIbrY=

modules/nm-applet/module.json

@@ -0,0 +1,37 @@
+{
+  "module": "nm-applet",
+  "version": "1",
+  "capabilities": [
+    "package-manager"
+  ],
+  "requires": [
+    "x11-display"
+  ],
+  "tools": [
+    "nm_applet_status",
+    "nm_applet_restart",
+    "nm_applet_check"
+  ],
+  "resources": [
+    {
+      "id": "package",
+      "type": "package",
+      "package": "network-manager-applet"
+    }
+  ],
+  "build": {
+    "artifacts": [
+      {
+        "name": "tools",
+        "kind": "bundle",
+        "language": "go",
+        "system": "arch",
+        "from": "cmd/nm-applet-tools",
+        "binary": "nm-applet-tools",
+        "loads": [
+          "nm-applet-tools"
+        ]
+      }
+    ]
+  }
+}

modules/openrazer/README.md

@@ -0,0 +1,106 @@
+# openrazer
+
+The Razer peripherals' kernel driver and the account's daemon that drives it, on the workstations, as
+a module (novox/hq ADR 0208: one module per piece of software). The tray that shows the devices is
+the `polychromatic` module's. This module needs no display: the daemon speaks to the driver and to its
+clients on the session bus.
+
+## Owns
+
+| what | where |
+|---|---|
+| the kernel driver's source, built by DKMS for each installed kernel (`razerkbd`, `razermouse`, `razerkraken`, `razeraccessory`) | package `openrazer-driver-dkms` |
+| the daemon (`org.razer` on the session bus) and its user unit | package `openrazer-daemon` |
+| the client library every front end speaks to the daemon through | package `python-openrazer` |
+
+All three from the official repositories (`extra`). On both workstations they are installed today as
+dependencies of the AUR tray, and become the mesh's here.
+
+**Why two modules and not one `razer`:** the driver and the daemon are one project, in the official
+repositories, and any front end uses them. The tray is another project, outside the official
+repositories. That is the line between `bluetooth` and `blueman` too. A machine can hold the stack
+without the tray, for a front end of the operator's own or for the daemon's persistence of the
+devices' lighting and DPI.
+
+Not this module's:
+
+- **The kernel headers DKMS builds against** (`linux-headers`). They are the kernel's, and every DKMS
+  driver on a machine needs them (the laptop also builds `nvidia`, the desktop `vboxhost` and `xone`).
+  No module declares them yet. `openrazer_check` says when the driver is not built for the running
+  kernel.
+- **`dkms` itself**, which the driver package depends on.
+- **The account's membership of the `openrazer` group** (below).
+
+## The group: a step for the operator, once
+
+The driver's udev rules give each device's files to the group `openrazer`, which the driver package
+creates (sysusers). The daemon refuses to start for an account outside that group: *User is not a
+member of the openrazer group*.
+
+**On both workstations the account is not in it today, so the daemon has failed at every start**
+since openrazer moved from `plugdev` to its own group. The tray runs, and shows no devices. The
+account is still in `plugdev`, which openrazer no longer uses. Another device's rules may (the laptop
+has a Logitech receiver rule that does), so it stays.
+
+The module cannot declare the membership. The host's `user` resource takes groups, additively, but the
+`zsh` module already declares the operator's account as its `user` resource. A second module declaring
+the same account is refused at composition, as two owners of one name. Until the mesh can add a group
+to the account from a second module, this is the operator's step (below), and `openrazer_check` holds
+it.
+
+## How it starts: D-Bus activation, and nothing else
+
+The package installs `org.razer` as a D-Bus service whose `SystemdService` is the user unit
+`openrazer-daemon.service`. The first client that asks for `org.razer` starts the daemon through that
+unit: at login, the tray's helper (`polychromatic-helper --autostart`). **That activation is the
+daemon's one start.** One unit, so it is never two daemons.
+
+- The unit is **not enabled** on either workstation, and the module does not enable it. Enabling it
+  would start the same unit at login a moment earlier, with nothing gained.
+- Asked by a tool, the bus is always called with `--auto-start=no`, so asking never starts it.
+
+## Tools
+
+They are served by the node's runtime as the operator account (ADR 0175).
+
+| tool | does |
+|---|---|
+| `openrazer_status` (r) | <ul><li>the three packages' versions</li><li>the driver: the running kernel, DKMS's state for it, the modules loaded, the devices bound (USB id, driver, interfaces)</li><li>the group: whether the account is in it, and whether the account's running service manager has it</li><li>the daemon: its unit's active and enabled states, its process, its version, and, when its unit failed, the reason it gave</li><li>each device the daemon sees: name, type, firmware, battery and charging where the device has them. Never its serial</li></ul> |
+| `openrazer_restart` (a) | restarts `openrazer-daemon.service` in the account's service manager and answers the devices it then sees. When it fails, the answer carries the daemon's own reason |
+| `openrazer_check` (r) | <ul><li>the packages are installed</li><li>the driver is built for the running kernel, and loaded</li><li>a device is bound</li><li>the account is in `openrazer`, and its service manager has the group (a group added after login needs a new login)</li><li>one start: the activation file is present, no window-manager exec</li><li>one daemon runs, from its unit, and answers</li><li>it sees every device the driver holds</li></ul>Each finding says what to do |
+
+Every command has a timeout and capped output. Everything runs through an injected runner and a fake
+root in the tests.
+
+## What changes when it is assigned
+
+| | laptop | desktop |
+|---|---|---|
+| packages | none: the three are installed, 3.12.4, as dependencies of the tray | the same |
+| driver | none: built for the running kernel, `razermouse` loaded, a Basilisk V3 Pro bound | the same, a Basilisk V2 bound |
+| daemon | none: the unit stays disabled; it failed at login (not in the group) | the same |
+
+## Migration (ADR 0182)
+
+On each workstation, once:
+
+1. `sudo gpasswd -a $USER openrazer`
+2. Log out of every session, or reboot. The account's service manager takes its groups when it
+   starts, and the daemon runs under it.
+3. `openrazer_check` answers `ok`, and the tray shows the devices.
+
+`plugdev` stays. Nothing else is required.
+
+## Leaves as found
+
+- The daemon's settings and persistence under `~/.config/openrazer/`, and its log under
+  `~/.local/share/openrazer/`.
+- `plugdev` and every other group of the account.
+- The kernel headers and DKMS.
+
+## Relies on
+
+- **The account in `openrazer`**, by hand (above).
+- **A client to start the daemon.** At login that is the `polychromatic` module's tray helper.
+  Without a client nothing asks, and nothing needs it to run.
+- **The kernel headers of every installed kernel**, for DKMS.

modules/openrazer/cmd/openrazer-tools/copies_test.go

@@ -0,0 +1,37 @@
+package main
+
+// The desktop applications whose bundles carry desktop.go. Each builds alone, so each has its own copy;
+// this test, itself one of the copied files, holds them to one text wherever the siblings are present.
+
+import (
+	"bytes"
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+var carriers = []string{"blueman", "forticlient", "nextcloud-client", "nm-applet", "openrazer", "polychromatic", "slack"}
+
+func TestEveryDesktopApplicationCarriesTheSameCopy(t *testing.T) {
+	compared := 0
+	for _, module := range carriers {
+		dir := filepath.Join("..", "..", "..", module, "cmd", module+"-tools")
+		if _, err := os.Stat(dir); err != nil {
+			continue
+		}
+		for _, f := range []string{"desktop.go", "desktop_test.go", "copies_test.go"} {
+			mine, err := os.ReadFile(f)
+			if err != nil {
+				t.Fatal(err)
+			}
+			theirs, err := os.ReadFile(filepath.Join(dir, f))
+			if err != nil || !bytes.Equal(mine, theirs) {
+				t.Errorf("%s's copy of %s differs from this one: change every copy together", module, f)
+			}
+		}
+		compared++
+	}
+	if compared == 0 {
+		t.Log("no sibling copies beside this module")
+	}
+}

modules/openrazer/cmd/openrazer-tools/desktop.go

@@ -0,0 +1,601 @@
+package main
+
+// desktop.go is the same file in every desktop application's bundle (copies_test.go names them and
+// holds them to one text): a tray application of the operator's graphical session, seen from the
+// node's tool runtime (novox/hq ADR 0208).
+//
+// The runtime is a system service running as the operator account (ADR 0175): it has the account's
+// uid and none of the session's environment. A tool that starts something on the desktop finds the
+// session from a process of the account that carries DISPLAY (the window manager first), and starts
+// the program under the account's own service manager with `systemd-run --user`, never as its own
+// child: the runtime's unit is a cgroup that is emptied whenever the runtime restarts.
+//
+// Everything a tool touches goes through a Machine: its filesystem root, its commands (a Runner) and
+// its signals are injected, so the tests run against a fake /proc and a fake home.
+//
+// Bounds: one command gets at most CallTimeout (below the runtime's 30 s call limit) and is ended
+// with everything it started when it takes longer; each stream is kept to MostOutput; a file is read
+// to at most MostRead.
+
+import (
+	"bufio"
+	"bytes"
+	"context"
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"sort"
+	"strconv"
+	"strings"
+	"syscall"
+	"time"
+)
+
+// Bounds every command and read is held to.
+const (
+	CallTimeout = 10 * time.Second
+	MostOutput  = 256 << 10
+	MostRead    = 16 << 20
+)
+
+// Output is what a command did.
+type Output struct {
+	Stdout string
+	Stderr string
+	Code   int
+	// Err is why it did not run to an answer: not installed, ended on its timeout, or the spawn error.
+	Err error
+	Cut bool
+}
+
+// ErrNotInstalled and ErrTimedOut are what a Runner answers in Output.Err.
+var (
+	ErrNotInstalled = errors.New("not installed")
+	ErrTimedOut     = errors.New("timed out")
+	// ErrNoSession is answered by a tool that needs the desktop when nobody is logged in to it.
+	ErrNoSession = errors.New("no graphical session")
+)
+
+// Runner runs one command with extra environment, within the context's deadline. Tests replace it.
+type Runner func(ctx context.Context, env []string, name string, args ...string) Output
+
+// Machine is what the tools read and act on.
+type Machine struct {
+	Root    string // "" on the machine; a fake root in tests
+	Home    string // the operator's home, as the machine names it
+	UID     int
+	Run     Runner
+	Kill    func(pid int, sig syscall.Signal) error
+	Sleep   func(time.Duration)
+	Now     func() time.Time
+	Timeout time.Duration
+}
+
+// NewMachine is the machine the bundle runs on.
+func NewMachine() *Machine {
+	return &Machine{Home: operatorHome(), UID: os.Getuid(), Run: execRun, Kill: syscall.Kill,
+		Sleep: time.Sleep, Now: time.Now, Timeout: CallTimeout}
+}
+
+// operatorHome is the account's home: what the runtime was told, else the process's own.
+func operatorHome() string {
+	if h := strings.TrimSpace(os.Getenv("MESH_OPERATOR_HOME")); h != "" {
+		return h
+	}
+	h, _ := os.UserHomeDir()
+	return h
+}
+
+func (m *Machine) path(p string) string { return filepath.Join(m.Root, p) }
+
+// home is a path under the operator's home, on this machine's filesystem.
+func (m *Machine) home(rel ...string) string {
+	return filepath.Join(append([]string{m.Root, m.Home}, rel...)...)
+}
+
+// tilde shows a path under the home as ~/…, so an answer does not carry the account's name.
+func (m *Machine) tilde(p string) string {
+	if m.Home != "" && m.Home != "/" {
+		h := strings.TrimSuffix(m.Home, "/")
+		if p == h {
+			return "~"
+		}
+		if strings.HasPrefix(p, h+"/") {
+			return "~/" + strings.TrimPrefix(p, h+"/")
+		}
+	}
+	return p
+}
+
+// cmd runs a command within the machine's timeout (or a shorter one).
+func (m *Machine) cmd(timeout time.Duration, env []string, name string, args ...string) Output {
+	if timeout <= 0 || timeout > m.Timeout {
+		timeout = m.Timeout
+	}
+	ctx, cancel := context.WithTimeout(context.Background(), timeout)
+	defer cancel()
+	return m.Run(ctx, env, name, args...)
+}
+
+// failed names how a command failed, or answers nil when it ran and exited 0.
+func failed(o Output, name string, args ...string) error {
+	switch {
+	case errors.Is(o.Err, ErrNotInstalled):
+		return fmt.Errorf("%s is not installed on this machine", name)
+	case errors.Is(o.Err, ErrTimedOut):
+		return fmt.Errorf("%s gave no answer in time and was ended", name)
+	case o.Err != nil:
+		return fmt.Errorf("%s did not run: %v", name, o.Err)
+	case o.Code != 0:
+		said := strings.TrimSpace(o.Stderr)
+		if said == "" {
+			said = strings.TrimSpace(o.Stdout)
+		}
+		if said == "" {
+			said = "and said nothing"
+		}
+		return fmt.Errorf("%s %s exited %d: %s", name, strings.Join(args, " "), o.Code, tail(said, 1000))
+	}
+	return nil
+}
+
+func tail(s string, n int) string {
+	if len(s) <= n {
+		return s
+	}
+	return "…" + s[len(s)-n:]
+}
+
+type capped struct {
+	b   bytes.Buffer
+	cut bool
+}
+
+func (c *capped) Write(p []byte) (int, error) {
+	if room := MostOutput - c.b.Len(); room < len(p) {
+		if room > 0 {
+			c.b.Write(p[:room])
+		}
+		c.cut = true
+		return len(p), nil
+	}
+	return c.b.Write(p)
+}
+
+func execRun(ctx context.Context, env []string, name string, args ...string) Output {
+	path, err := exec.LookPath(name)
+	if err != nil {
+		return Output{Code: 127, Err: ErrNotInstalled}
+	}
+	cmd := exec.CommandContext(ctx, path, args...)
+	cmd.Env = append(append(os.Environ(), "LC_ALL=C"), env...)
+	// Its own process group, so that ending it on a timeout ends what it started too.
+	cmd.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
+	cmd.Cancel = func() error {
+		if cmd.Process != nil {
+			_ = syscall.Kill(-cmd.Process.Pid, syscall.SIGKILL)
+		}
+		return nil
+	}
+	cmd.WaitDelay = 2 * time.Second
+	var out, errs capped
+	cmd.Stdout, cmd.Stderr = &out, &errs
+	err = cmd.Run()
+	o := Output{Stdout: out.b.String(), Stderr: errs.b.String(), Cut: out.cut || errs.cut}
+	var exit *exec.ExitError
+	switch {
+	case err == nil:
+	case ctx.Err() == context.DeadlineExceeded:
+		o.Code, o.Err = 124, ErrTimedOut
+	case errors.As(err, &exit):
+		o.Code = exit.ExitCode()
+	default:
+		o.Code, o.Err = 127, err
+	}
+	return o
+}
+
+// readBounded reads a file to at most MostRead bytes.
+func readBounded(path string) ([]byte, error) {
+	f, err := os.Open(path)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+	return io.ReadAll(io.LimitReader(f, MostRead))
+}
+
+// Proc is one process of the account.
+type Proc struct {
+	PID     int    `json:"pid"`
+	Command string `json:"command"`
+	// StartedIn is the unit or scope it runs in: the login session's scope when the session's start
+	// (dex, the window manager) started it, a mesh-… unit when a tool restarted it.
+	StartedIn string `json:"started_in,omitempty"`
+	Since     string `json:"since,omitempty"`
+}
+
+// procs are this account's processes named comm, oldest first.
+func (m *Machine) procs(comm string) []Proc {
+	entries, err := os.ReadDir(m.path("/proc"))
+	if err != nil {
+		return nil
+	}
+	boot := m.bootTime()
+	var out []Proc
+	for _, e := range entries {
+		pid, err := strconv.Atoi(e.Name())
+		if err != nil {
+			continue
+		}
+		dir := m.path(filepath.Join("/proc", e.Name()))
+		if readTrimmed(filepath.Join(dir, "comm")) != comm || m.uidOf(dir) != m.UID {
+			continue
+		}
+		p := Proc{PID: pid, Command: strings.TrimSpace(strings.ReplaceAll(readTrimmed(filepath.Join(dir, "cmdline")), "\x00", " "))}
+		if p.Command == "" {
+			p.Command = comm
+		}
+		if cg := readTrimmed(filepath.Join(dir, "cgroup")); cg != "" {
+			line := strings.Split(cg, "\n")[0]
+			p.StartedIn = filepath.Base(line[strings.LastIndexByte(line, ':')+1:])
+		}
+		if t, ok := startOf(readTrimmed(filepath.Join(dir, "stat")), boot); ok {
+			p.Since = t.UTC().Format(time.RFC3339)
+		}
+		out = append(out, p)
+	}
+	sort.Slice(out, func(i, j int) bool { return out[i].PID < out[j].PID })
+	return out
+}
+
+// procsOf are the account's processes named comm whose program is word. The kernel keeps 15
+// characters of a command name, so a longer name can share them with another program's: this bundle's
+// own binary among them (polychromatic-tools and polychromatic-tray-applet are both polychromatic-t).
+// The program is the first word of the command line, or the second for a script run by its
+// interpreter. An empty word keeps every process named comm.
+func (m *Machine) procsOf(comm, word string) []Proc {
+	var out []Proc
+	for _, p := range m.procs(comm) {
+		f := strings.Fields(p.Command)
+		if word == "" || (len(f) > 0 && filepath.Base(f[0]) == word) || (len(f) > 1 && filepath.Base(f[1]) == word) {
+			out = append(out, p)
+		}
+	}
+	return out
+}
+
+// uidOf is the real uid on a process's status, -1 when unreadable.
+func (m *Machine) uidOf(dir string) int {
+	for _, l := range strings.Split(readTrimmed(filepath.Join(dir, "status")), "\n") {
+		if f := strings.Fields(l); len(f) > 1 && f[0] == "Uid:" {
+			if n, err := strconv.Atoi(f[1]); err == nil {
+				return n
+			}
+		}
+	}
+	return -1
+}
+
+func (m *Machine) bootTime() int64 {
+	for _, l := range strings.Split(readTrimmed(m.path("/proc/stat")), "\n") {
+		if f := strings.Fields(l); len(f) == 2 && f[0] == "btime" {
+			n, _ := strconv.ParseInt(f[1], 10, 64)
+			return n
+		}
+	}
+	return 0
+}
+
+// startOf reads a process's start from its stat line (field 22, in clock ticks of 1/100 s since boot).
+func startOf(stat string, boot int64) (time.Time, bool) {
+	i := strings.LastIndexByte(stat, ')')
+	if i < 0 || boot == 0 {
+		return time.Time{}, false
+	}
+	f := strings.Fields(stat[i+1:])
+	if len(f) < 20 {
+		return time.Time{}, false
+	}
+	ticks, err := strconv.ParseInt(f[19], 10, 64)
+	if err != nil {
+		return time.Time{}, false
+	}
+	return time.Unix(boot+ticks/100, 0), true
+}
+
+func readTrimmed(path string) string {
+	b, err := os.ReadFile(path)
+	if err != nil {
+		return ""
+	}
+	return strings.TrimSpace(string(b))
+}
+
+func exists(path string) bool {
+	_, err := os.Stat(path)
+	return err == nil
+}
+
+// Session is what a tool needs to start something on the operator's desktop.
+type Session struct {
+	Display    string `json:"display"`
+	XAuthority string `json:"xauthority,omitempty"`
+	Bus        string `json:"bus,omitempty"`
+	RuntimeDir string `json:"runtime_dir,omitempty"`
+	From       string `json:"found_in"`
+}
+
+// sessionHolders are the processes whose environment is the session's, best first.
+var sessionHolders = []string{"i3", "sway", "i3bar", "picom", "dunst", "xterm"}
+
+// session finds the account's graphical session, or ErrNoSession saying what it looked at.
+func (m *Machine) session() (Session, error) {
+	entries, _ := os.ReadDir(m.path("/proc"))
+	best, bestRank := -1, len(sessionHolders)+1
+	var env map[string]string
+	var from string
+	for _, e := range entries {
+		pid, err := strconv.Atoi(e.Name())
+		if err != nil {
+			continue
+		}
+		dir := m.path(filepath.Join("/proc", e.Name()))
+		if m.uidOf(dir) != m.UID {
+			continue
+		}
+		raw, err := os.ReadFile(filepath.Join(dir, "environ"))
+		if err != nil {
+			continue
+		}
+		vars := parseEnviron(raw)
+		if vars["DISPLAY"] == "" {
+			continue
+		}
+		comm := readTrimmed(filepath.Join(dir, "comm"))
+		rank := len(sessionHolders)
+		for i, h := range sessionHolders {
+			if h == comm {
+				rank = i
+			}
+		}
+		if rank < bestRank || (rank == bestRank && pid > best) {
+			best, bestRank, env, from = pid, rank, vars, fmt.Sprintf("process %s (pid %d)", comm, pid)
+		}
+	}
+	if env == nil {
+		return Session{}, fmt.Errorf("%w for uid %d on this machine: no process of the account carries DISPLAY. "+
+			"Is anyone logged in to the desktop?", ErrNoSession, m.UID)
+	}
+	s := Session{Display: env["DISPLAY"], XAuthority: env["XAUTHORITY"], Bus: env["DBUS_SESSION_BUS_ADDRESS"],
+		RuntimeDir: env["XDG_RUNTIME_DIR"], From: from}
+	if s.RuntimeDir == "" {
+		s.RuntimeDir = fmt.Sprintf("/run/user/%d", m.UID)
+	}
+	if s.Bus == "" && exists(m.path(filepath.Join(s.RuntimeDir, "bus"))) {
+		s.Bus = "unix:path=" + filepath.Join(s.RuntimeDir, "bus")
+	}
+	return s, nil
+}
+
+// bus is the account's session bus environment, which a logged-in account has with or without a
+// desktop: what a command needs to reach the user's service manager or a bus name.
+func (m *Machine) bus() []string {
+	runtime := fmt.Sprintf("/run/user/%d", m.UID)
+	return []string{"XDG_RUNTIME_DIR=" + runtime, "DBUS_SESSION_BUS_ADDRESS=unix:path=" + runtime + "/bus"}
+}
+
+// Env is the session's variables, for a command that draws or speaks to the desktop.
+func (s Session) Env() []string {
+	var env []string
+	for _, kv := range [][2]string{{"DISPLAY", s.Display}, {"XAUTHORITY", s.XAuthority},
+		{"DBUS_SESSION_BUS_ADDRESS", s.Bus}, {"XDG_RUNTIME_DIR", s.RuntimeDir}} {
+		if kv[1] != "" {
+			env = append(env, kv[0]+"="+kv[1])
+		}
+	}
+	return env
+}
+
+func parseEnviron(raw []byte) map[string]string {
+	env := map[string]string{}
+	for _, kv := range bytes.Split(raw, []byte{0}) {
+		if i := bytes.IndexByte(kv, '='); i > 0 {
+			env[string(kv[:i])] = string(kv[i+1:])
+		}
+	}
+	return env
+}
+
+// detach starts a long-lived program under the account's service manager, as a transient unit that
+// carries the session's display. A unit left by an earlier start under the same name is stopped
+// first, so the fixed name means at most one.
+func (m *Machine) detach(s Session, unit string, argv ...string) error {
+	_ = m.cmd(5*time.Second, s.Env(), "systemctl", "--user", "stop", unit+".service")
+	call := []string{"--user", "--collect", "--quiet", "--unit=" + unit}
+	for _, kv := range [][2]string{{"DISPLAY", s.Display}, {"XAUTHORITY", s.XAuthority}} {
+		if kv[1] != "" {
+			call = append(call, "--setenv="+kv[0]+"="+kv[1])
+		}
+	}
+	call = append(append(call, "--"), argv...)
+	return failed(m.cmd(8*time.Second, s.Env(), "systemd-run", call...), "systemd-run", call...)
+}
+
+// stop ends every process of the account named in comms: SIGTERM, then SIGKILL for what is still
+// there after grace. It answers the pids that ended and those that had to be killed.
+func (m *Machine) stop(grace time.Duration, comms ...string) (ended, killed []int) {
+	var ps []Proc
+	for _, c := range comms {
+		ps = append(ps, m.procs(c)...)
+	}
+	return m.stopProcs(grace, ps)
+}
+
+// stopProcs ends the processes given, as stop does.
+func (m *Machine) stopProcs(grace time.Duration, ps []Proc) (ended, killed []int) {
+	var pids []int
+	for _, p := range ps {
+		if m.Kill(p.PID, syscall.SIGTERM) == nil {
+			pids = append(pids, p.PID)
+		}
+	}
+	alive := func() []int {
+		var left []int
+		for _, pid := range pids {
+			if exists(m.path(filepath.Join("/proc", strconv.Itoa(pid)))) {
+				left = append(left, pid)
+			}
+		}
+		return left
+	}
+	step := 200 * time.Millisecond
+	for waited := time.Duration(0); waited < grace && len(alive()) > 0; waited += step {
+		m.Sleep(step)
+	}
+	left := alive()
+	for _, pid := range left {
+		if m.Kill(pid, syscall.SIGKILL) == nil {
+			killed = append(killed, pid)
+		}
+	}
+	gone := map[int]bool{}
+	for _, pid := range left {
+		gone[pid] = true
+	}
+	for _, pid := range pids {
+		if !gone[pid] {
+			ended = append(ended, pid)
+		}
+	}
+	return ended, killed
+}
+
+// waitFor waits up to d for a process of the account named comm, and answers what it found.
+func (m *Machine) waitFor(comm string, d time.Duration) []Proc { return m.waitForOf(comm, "", d) }
+
+// waitForOf waits up to d for a process of the account named comm whose program is word (procsOf).
+func (m *Machine) waitForOf(comm, word string, d time.Duration) []Proc {
+	step := 250 * time.Millisecond
+	for waited := time.Duration(0); ; waited += step {
+		if p := m.procsOf(comm, word); len(p) > 0 || waited >= d {
+			return p
+		}
+		m.Sleep(step)
+	}
+}
+
+// desktopEntry reads the [Desktop Entry] group of an XDG desktop file; nil when there is none.
+func desktopEntry(path string) map[string]string {
+	raw, err := readBounded(path)
+	if err != nil {
+		return nil
+	}
+	out := map[string]string{}
+	in := false
+	s := bufio.NewScanner(bytes.NewReader(raw))
+	for s.Scan() {
+		l := strings.TrimSpace(s.Text())
+		switch {
+		case strings.HasPrefix(l, "["):
+			in = l == "[Desktop Entry]"
+		case in && l != "" && !strings.HasPrefix(l, "#"):
+			if i := strings.IndexByte(l, '='); i > 0 {
+				out[strings.TrimSpace(l[:i])] = strings.TrimSpace(l[i+1:])
+			}
+		}
+	}
+	return out
+}
+
+// Autostart is what XDG autostart does with one entry: the account's file overrides the system's
+// of the same name, and Hidden=true (or the GNOME switch off) means it is not started.
+type Autostart struct {
+	Entry   string `json:"entry"`
+	From    string `json:"from"`
+	Exec    string `json:"exec,omitempty"`
+	Starts  bool   `json:"starts"`
+	Because string `json:"because,omitempty"`
+}
+
+// autostart resolves one XDG autostart entry by its file name, the account's directory first.
+func (m *Machine) autostart(name string) Autostart {
+	a := Autostart{Entry: name}
+	user := m.home(".config", "autostart", name)
+	system := m.path(filepath.Join("/etc/xdg/autostart", name))
+	var e map[string]string
+	switch {
+	case exists(user):
+		e, a.From = desktopEntry(user), m.tilde(filepath.Join(m.Home, ".config/autostart", name))
+	case exists(system):
+		e, a.From = desktopEntry(system), filepath.Join("/etc/xdg/autostart", name)
+	default:
+		a.Because = "no such entry in ~/.config/autostart or /etc/xdg/autostart"
+		return a
+	}
+	a.Exec = e["Exec"]
+	switch {
+	case strings.EqualFold(e["Hidden"], "true"):
+		a.Because = "Hidden=true"
+	case strings.EqualFold(e["X-GNOME-Autostart-enabled"], "false"):
+		a.Because = "X-GNOME-Autostart-enabled=false"
+	case a.Exec == "":
+		a.Because = "the entry has no Exec"
+	default:
+		a.Starts = true
+	}
+	return a
+}
+
+// i3Starts are the window manager's start-up lines (exec, exec_always) that run a program named
+// word, in the configuration and its config.d: a second start beside an autostart entry.
+func (m *Machine) i3Starts(word string) []string {
+	files := []string{m.home(".config", "i3", "config")}
+	more, _ := filepath.Glob(m.home(".config", "i3", "config.d", "*.conf"))
+	files = append(files, more...)
+	var out []string
+	for _, f := range files {
+		raw, err := readBounded(f)
+		if err != nil {
+			continue
+		}
+		for n, l := range strings.Split(string(raw), "\n") {
+			t := strings.TrimSpace(l)
+			if !strings.HasPrefix(t, "exec ") && !strings.HasPrefix(t, "exec_always ") {
+				continue
+			}
+			for _, w := range strings.Fields(t)[1:] {
+				if filepath.Base(strings.Trim(w, `"'`)) == word {
+					out = append(out, fmt.Sprintf("%s:%d: %s", m.tilde(strings.TrimPrefix(f, m.Root)), n+1, t))
+					break
+				}
+			}
+		}
+	}
+	return out
+}
+
+// installed asks the package manager for one package's version; "" when it is not installed.
+func (m *Machine) installed(pkg string) (string, error) {
+	o := m.cmd(0, nil, "pacman", "-Q", pkg)
+	if o.Err != nil {
+		return "", failed(o, "pacman", "-Q", pkg)
+	}
+	if o.Code != 0 {
+		return "", nil
+	}
+	f := strings.Fields(o.Stdout)
+	if len(f) < 2 {
+		return "", fmt.Errorf("pacman -Q %s answered %q", pkg, o.Stdout)
+	}
+	return f[1], nil
+}
+
+// Finding is one thing a check found wrong, and what to do about it.
+type Finding struct {
+	What string `json:"what"`
+	Do   string `json:"do,omitempty"`
+}

modules/openrazer/cmd/openrazer-tools/desktop_test.go

@@ -0,0 +1,219 @@
+package main
+
+// The fake machine the tests run against, and the tests of desktop.go. The same in every desktop
+// application's bundle (copies_test.go).
+
+import (
+	"context"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"sync"
+	"syscall"
+	"testing"
+	"time"
+)
+
+const testHome = "/home/operator"
+
+// fake is a machine with a fake root, a scripted Runner and signals that end fake processes.
+type fake struct {
+	*Machine
+	t      *testing.T
+	mu     sync.Mutex
+	calls  []string
+	answer func(name string, args []string) Output
+	// onStart is run when systemd-run starts something, to let a fake process appear.
+	onStart func(argv []string)
+	// stubborn pids ignore SIGTERM.
+	stubborn map[int]bool
+	signals  []string
+}
+
+func newFake(t *testing.T) *fake {
+	t.Helper()
+	root := t.TempDir()
+	f := &fake{t: t, stubborn: map[int]bool{}}
+	f.Machine = &Machine{Root: root, Home: testHome, UID: 1000, Timeout: CallTimeout,
+		Sleep: func(time.Duration) {}, Now: func() time.Time { return time.Unix(1_800_000_000, 0) }}
+	f.Run = func(_ context.Context, env []string, name string, args ...string) Output {
+		f.mu.Lock()
+		f.calls = append(f.calls, strings.TrimSpace(name+" "+strings.Join(args, " ")))
+		f.mu.Unlock()
+		if name == "systemd-run" && f.onStart != nil {
+			for i, a := range args {
+				if a == "--" {
+					f.onStart(args[i+1:])
+				}
+			}
+		}
+		if f.answer != nil {
+			return f.answer(name, args)
+		}
+		return Output{}
+	}
+	f.Kill = func(pid int, sig syscall.Signal) error {
+		f.signals = append(f.signals, strconv.Itoa(pid)+":"+sig.String())
+		if sig == syscall.SIGKILL || !f.stubborn[pid] {
+			return os.RemoveAll(filepath.Join(root, "proc", strconv.Itoa(pid)))
+		}
+		return nil
+	}
+	f.write("/proc/stat", "cpu 1 2 3\nbtime 1799990000\n")
+	return f
+}
+
+func (f *fake) write(path, content string) {
+	f.t.Helper()
+	p := filepath.Join(f.Root, path)
+	if err := os.MkdirAll(filepath.Dir(p), 0o755); err != nil {
+		f.t.Fatal(err)
+	}
+	if err := os.WriteFile(p, []byte(content), 0o644); err != nil {
+		f.t.Fatal(err)
+	}
+}
+
+// proc adds a process of uid with a command name, argv, cgroup and environment.
+func (f *fake) proc(pid, uid int, comm string, argv []string, cgroup string, env ...string) {
+	d := "/proc/" + strconv.Itoa(pid) + "/"
+	f.write(d+"comm", comm+"\n")
+	f.write(d+"status", "Name:\t"+comm+"\nUid:\t"+strconv.Itoa(uid)+"\t"+strconv.Itoa(uid)+"\t"+strconv.Itoa(uid)+"\t"+strconv.Itoa(uid)+"\n")
+	f.write(d+"cmdline", strings.Join(argv, "\x00")+"\x00")
+	f.write(d+"cgroup", "0::/user.slice/user-"+strconv.Itoa(uid)+".slice/"+cgroup+"\n")
+	f.write(d+"environ", strings.Join(env, "\x00")+"\x00")
+	// starttime (field 22) is 1000 ticks: 10 s after boot.
+	f.write(d+"stat", strconv.Itoa(pid)+" ("+comm+") S 1 1 1 0 -1 0 0 0 0 0 0 0 0 0 20 0 1 0 1000 0 0\n")
+}
+
+func (f *fake) desktopSession() {
+	f.proc(3700, 1000, "i3", []string{"i3"}, "session-c1.scope", "DISPLAY=:1", "XAUTHORITY="+testHome+"/.Xauthority")
+	f.write("/run/user/1000/bus", "")
+}
+
+func (f *fake) called(prefix string) bool {
+	for _, c := range f.calls {
+		if strings.HasPrefix(c, prefix) {
+			return true
+		}
+	}
+	return false
+}
+
+func TestProcessesAreTheAccountsOwnWithWhereAndWhenTheyStarted(t *testing.T) {
+	f := newFake(t)
+	f.proc(10, 1000, "worker", []string{"/usr/bin/worker", "--background"}, "session-c1.scope")
+	f.proc(11, 1001, "worker", []string{"/usr/bin/worker"}, "session-c2.scope")
+	f.proc(12, 1000, "other", []string{"other"}, "x.scope")
+	got := f.procs("worker")
+	if len(got) != 1 || got[0].PID != 10 || got[0].Command != "/usr/bin/worker --background" ||
+		got[0].StartedIn != "session-c1.scope" || got[0].Since != time.Unix(1799990010, 0).UTC().Format(time.RFC3339) {
+		t.Fatalf("%+v", got)
+	}
+}
+
+func TestAProgramIsToldFromAnotherSharingItsCutName(t *testing.T) {
+	f := newFake(t)
+	f.proc(10, 1000, "polychromatic-t", []string{"/usr/bin/python", "/usr/bin/polychromatic-tray-applet"}, "s.scope")
+	f.proc(11, 1000, "polychromatic-t", []string{"polychromatic-tray-applet"}, "s.scope")
+	f.proc(12, 1000, "polychromatic-t", []string{"/usr/lib/mesh/polychromatic-tools"}, "s.scope")
+	if got := f.procsOf("polychromatic-t", "polychromatic-tray-applet"); len(got) != 2 || got[0].PID != 10 || got[1].PID != 11 {
+		t.Fatalf("%+v", got)
+	}
+	if got := f.procsOf("polychromatic-t", ""); len(got) != 3 {
+		t.Fatalf("%+v", got)
+	}
+	ended, _ := f.stopProcs(time.Second, f.procsOf("polychromatic-t", "polychromatic-tray-applet"))
+	if len(ended) != 2 || len(f.procs("polychromatic-t")) != 1 {
+		t.Fatalf("ended %v; the tools' own process must stay", ended)
+	}
+}
+
+func TestTheSessionIsTheWindowManagersAndNoneIsSaidPlainly(t *testing.T) {
+	f := newFake(t)
+	if _, err := f.session(); err == nil || !strings.Contains(err.Error(), "no graphical session") {
+		t.Fatalf("%v", err)
+	}
+	f.proc(50, 1000, "xterm", []string{"xterm"}, "s.scope", "DISPLAY=:9")
+	f.desktopSession()
+	f.proc(60, 1001, "i3", []string{"i3"}, "s.scope", "DISPLAY=:5")
+	s, err := f.session()
+	if err != nil || s.Display != ":1" || s.XAuthority != testHome+"/.Xauthority" || s.Bus != "unix:path=/run/user/1000/bus" ||
+		!strings.Contains(s.From, "i3") {
+		t.Fatalf("%+v %v", s, err)
+	}
+}
+
+func TestStopAsksThenForcesAndDetachStartsUnderTheServiceManager(t *testing.T) {
+	f := newFake(t)
+	f.desktopSession()
+	f.proc(20, 1000, "app", []string{"app"}, "s.scope")
+	f.proc(21, 1000, "app", []string{"app"}, "s.scope")
+	f.stubborn[21] = true
+	ended, killed := f.stop(time.Second, "app")
+	if len(ended) != 1 || ended[0] != 20 || len(killed) != 1 || killed[0] != 21 {
+		t.Fatalf("ended %v killed %v (%v)", ended, killed, f.signals)
+	}
+	s, _ := f.session()
+	if err := f.detach(s, "mesh-app", "/usr/bin/app", "--background"); err != nil {
+		t.Fatal(err)
+	}
+	want := "systemd-run --user --collect --quiet --unit=mesh-app --setenv=DISPLAY=:1 --setenv=XAUTHORITY=" + testHome +
+		"/.Xauthority -- /usr/bin/app --background"
+	if !f.called("systemctl --user stop mesh-app.service") || !f.called(want) {
+		t.Fatalf("%q", f.calls)
+	}
+}
+
+func TestAnAutostartEntryOfTheAccountOverridesTheSystemsAndHiddenStartsNothing(t *testing.T) {
+	f := newFake(t)
+	if a := f.autostart("x.desktop"); a.Starts || a.Because == "" {
+		t.Fatalf("%+v", a)
+	}
+	f.write("/etc/xdg/autostart/x.desktop", "[Desktop Entry]\nExec=x-applet\n[Desktop Action y]\nExec=other\n")
+	if a := f.autostart("x.desktop"); !a.Starts || a.Exec != "x-applet" || a.From != "/etc/xdg/autostart/x.desktop" {
+		t.Fatalf("%+v", a)
+	}
+	f.write(testHome+"/.config/autostart/x.desktop", "[Desktop Entry]\nExec=x-applet\nHidden=true\n")
+	if a := f.autostart("x.desktop"); a.Starts || a.Because != "Hidden=true" || a.From != "~/.config/autostart/x.desktop" {
+		t.Fatalf("%+v", a)
+	}
+}
+
+func TestAWindowManagerStartIsFoundInTheConfigurationAndItsDropIns(t *testing.T) {
+	f := newFake(t)
+	f.write(testHome+"/.config/i3/config", "exec --no-startup-id dex --autostart --environment i3\n# exec app\nbindsym $mod+a exec app\n")
+	f.write(testHome+"/.config/i3/config.d/50-x.conf", "exec_always --no-startup-id /usr/bin/app --flag\n")
+	got := f.i3Starts("app")
+	if len(got) != 1 || got[0] != "~/.config/i3/config.d/50-x.conf:1: exec_always --no-startup-id /usr/bin/app --flag" {
+		t.Fatalf("%q", got)
+	}
+}
+
+func TestACommandThatFailsIsNamed(t *testing.T) {
+	if err := failed(Output{Code: 127, Err: ErrNotInstalled}, "dex"); err == nil || !strings.Contains(err.Error(), "dex is not installed") {
+		t.Fatal(err)
+	}
+	if err := failed(Output{Code: 1, Stderr: "nope"}, "pacman", "-Q", "x"); err == nil || !strings.Contains(err.Error(), "pacman -Q x exited 1: nope") {
+		t.Fatal(err)
+	}
+	if err := failed(Output{}, "true"); err != nil {
+		t.Fatal(err)
+	}
+}
+
+func TestTheRealRunnerBoundsTimeAndOutput(t *testing.T) {
+	ctx, cancel := context.WithTimeout(context.Background(), 200*time.Millisecond)
+	defer cancel()
+	if o := execRun(ctx, nil, "sleep", "5"); o.Err != ErrTimedOut {
+		t.Fatalf("%+v", o)
+	}
+	if o := execRun(context.Background(), nil, "no-such-program-here"); o.Err != ErrNotInstalled {
+		t.Fatalf("%+v", o)
+	}
+	o := execRun(context.Background(), nil, "head", "-c", strconv.Itoa(MostOutput+10), "/dev/zero")
+	if !o.Cut || len(o.Stdout) != MostOutput {
+		t.Fatalf("cut %v, %d bytes", o.Cut, len(o.Stdout))
+	}
+}

modules/openrazer/cmd/openrazer-tools/main.go

@@ -0,0 +1,50 @@
+// The openrazer module's Go tools bundle (novox/hq ADR 0188, ADR 0193, ADR 0208): the Razer
+// peripherals' kernel driver and the account's daemon that speaks to it, served by the node's runtime
+// as the operator account. The module holds no seat, so every tool is its own. The tray that drives
+// the daemon is the polychromatic module's.
+package main
+
+import (
+	"fmt"
+	"os"
+
+	stdio "git.novox.be/novox/mesh-sdk/go"
+)
+
+func main() {
+	if err := stdio.Serve("", tools()); err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+}
+
+var machine = NewMachine()
+
+func tools() []stdio.Tool {
+	return []stdio.Tool{
+		{
+			Name: "openrazer_status",
+			Description: "The Razer stack: the installed versions, the driver (built by DKMS for the running " +
+				"kernel or not, its kernel modules loaded, the devices bound to it), the account's openrazer " +
+				"group (in the group file, and in its running service manager), the daemon (its unit's state, " +
+				"its process, its version) and each device the daemon sees: name, type, firmware, battery. " +
+				"Asks the daemon without starting it. (r)",
+			Run: func(map[string]any) (any, error) { return machine.Status() },
+		},
+		{
+			Name: "openrazer_restart",
+			Description: "Restart the daemon through its unit in the account's service manager (the unit D-Bus " +
+				"activation starts), and answer its state and the devices it then sees. Needs the account " +
+				"logged in. (a)",
+			Run: func(map[string]any) (any, error) { return machine.Restart() },
+		},
+		{
+			Name: "openrazer_check",
+			Description: "Check what the module promises and relies on: the packages are installed; the driver " +
+				"is built for the running kernel and loaded; the account is in the openrazer group, and its " +
+				"service manager has it; the daemon runs once, from its unit, and sees the devices the driver " +
+				"has. Answers ok and each finding with what to do. (r)",
+			Run: func(map[string]any) (any, error) { return machine.Check() },
+		},
+	}
+}

modules/openrazer/cmd/openrazer-tools/manifest_test.go

@@ -0,0 +1,112 @@
+package main
+
+import (
+	"encoding/json"
+	"os"
+	"path/filepath"
+	"reflect"
+	"strings"
+	"testing"
+)
+
+// openrazer's shape (novox/hq ADR 0207, ADR 0208, ADR 0210): the three official packages of the
+// driver, the daemon and its client library, no seat, no display (the daemon needs none), no start of
+// its own (D-Bus activation through the package's unit is the one start), nothing of the tray's (the
+// polychromatic module's), and the Go bundle serving exactly the listed openrazer_ tools.
+
+type manifest struct {
+	Module        string           `json:"module"`
+	Version       string           `json:"version"`
+	Capabilities  []string         `json:"capabilities"`
+	Requires      []string         `json:"requires"`
+	Tools         []string         `json:"tools"`
+	Resources     []map[string]any `json:"resources"`
+	Claims        []any            `json:"claims"`
+	Seats         []any            `json:"seats"`
+	Shell         []any            `json:"shell"`
+	Contributions []struct {
+		Seat    string `json:"seat"`
+		Kind    string `json:"kind"`
+		Content string `json:"content"`
+	} `json:"contributions"`
+	Environment any `json:"environment"`
+	Build       struct {
+		Artifacts []map[string]any `json:"artifacts"`
+	} `json:"build"`
+}
+
+func readManifest(t *testing.T) (manifest, string) {
+	t.Helper()
+	raw, err := os.ReadFile(filepath.Join("..", "..", "module.json"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	dec := json.NewDecoder(strings.NewReader(string(raw)))
+	dec.DisallowUnknownFields()
+	var m manifest
+	if err := dec.Decode(&m); err != nil {
+		t.Fatalf("module.json: %v", err)
+	}
+	return m, string(raw)
+}
+
+func TestTheToolsAgreeWithTheManifest(t *testing.T) {
+	m, raw := readManifest(t)
+	served := map[string]bool{}
+	for _, tool := range tools() {
+		served[tool.Name] = true
+		if !strings.HasPrefix(tool.Name, "openrazer_") || strings.TrimSpace(tool.Description) == "" {
+			t.Errorf("%s: prefixed %s and described", tool.Name, "openrazer_")
+		}
+	}
+	for _, name := range m.Tools {
+		if !served[name] {
+			t.Errorf("module.json lists %s, which the bundle does not serve", name)
+		}
+		delete(served, name)
+	}
+	for name := range served {
+		t.Errorf("the bundle serves %s, which module.json does not list", name)
+	}
+	if len(m.Build.Artifacts) != 1 {
+		t.Fatalf("%v", m.Build.Artifacts)
+	}
+	b := m.Build.Artifacts[0]
+	if b["kind"] != "bundle" || b["language"] != "go" || b["system"] != "arch" ||
+		b["from"] != "cmd/openrazer-tools" || b["binary"] != "openrazer-tools" {
+		t.Errorf("the Go tools bundle: %v", b)
+	}
+	s := strings.ToLower(raw)
+	for _, never := range []string{"/home/", "jochen", "g14", "shanks", "novox.be", "http", "password", "token"} {
+		if strings.Contains(s, never) {
+			t.Errorf("module.json names %q", never)
+		}
+	}
+}
+
+func TestItInstallsTheStackAndStartsNothing(t *testing.T) {
+	m, raw := readManifest(t)
+	if m.Module != "openrazer" || m.Requires != nil || !reflect.DeepEqual(m.Capabilities, []string{"package-manager"}) {
+		t.Fatalf("%+v", m)
+	}
+	var pkgs []string
+	for _, r := range m.Resources {
+		if r["type"] != "package" {
+			t.Errorf("only packages: %v", r)
+		}
+		pkgs = append(pkgs, r["package"].(string))
+	}
+	if !reflect.DeepEqual(pkgs, packages) {
+		t.Fatalf("%v", pkgs)
+	}
+	if m.Claims != nil || m.Seats != nil || m.Environment != nil || m.Shell != nil || m.Contributions != nil {
+		t.Fatal("it holds no seat, sets no environment and adds no start")
+	}
+	// The tray is polychromatic's, from outside the official repositories; the kernel headers DKMS
+	// builds against are the kernel's; the account's groups are its user resource's (zsh's).
+	for _, never := range []string{"polychromatic", "linux-headers", "\"dkms\"", "\"user\"", "groups"} {
+		if strings.Contains(raw, never) {
+			t.Errorf("module.json names %s", never)
+		}
+	}
+}

modules/openrazer/cmd/openrazer-tools/openrazer.go

@@ -0,0 +1,499 @@
+package main
+
+// openrazer as the tools see it: the kernel driver (built by DKMS, loaded, holding devices), the
+// account's membership of the group the driver gives its devices to, and the daemon in the account's
+// service manager, asked over the session bus. Every bus call is made with --auto-start=no: the daemon
+// is D-Bus activatable, and a question must never start it.
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+	"path/filepath"
+	"regexp"
+	"sort"
+	"strconv"
+	"strings"
+	"time"
+)
+
+const (
+	dkmsName   = "openrazer-driver"
+	group      = "openrazer"
+	daemonComm = "openrazer-daemo" // the kernel keeps 15 characters of openrazer-daemon
+	daemonUnit = "openrazer-daemon.service"
+	busName    = "org.razer"
+	busRoot    = "/org/razer"
+	activation = "/usr/share/dbus-1/services/org.razer.service"
+	// mostDevices bounds the questions one answer asks the daemon.
+	mostDevices = 16
+)
+
+// packages are the module's, from the official repositories: the driver's DKMS source, the daemon,
+// and the Python library every front end (the tray among them) speaks to the daemon through.
+var packages = []string{"openrazer-driver-dkms", "openrazer-daemon", "python-openrazer"}
+
+// kernelModules are what the DKMS package builds (its dkms.conf).
+var kernelModules = []string{"razerkbd", "razermouse", "razerkraken", "razeraccessory"}
+
+// hidID is a HID device's name under its driver: bus:vendor:product.instance.
+// stamp is the daemon's own time at the front of its log lines, dropped so repeats are seen as one.
+var stamp = regexp.MustCompile(`^\d{4}-\d{2}-\d{2} \d{2}:\d{2}:\d{2}\s*\|\s*`)
+
+var hidID = regexp.MustCompile(`^[0-9A-Fa-f]{4}:([0-9A-Fa-f]{4}):([0-9A-Fa-f]{4})\.[0-9A-Fa-f]{4}$`)
+
+// Bound is one device the driver holds: its USB id, the driver module and how many of its HID
+// interfaces are bound.
+type Bound struct {
+	USB        string `json:"usb"`
+	Driver     string `json:"driver"`
+	Interfaces int    `json:"interfaces"`
+}
+
+// Driver is the kernel side.
+type Driver struct {
+	Kernel string `json:"running_kernel"`
+	// Built is DKMS's word for the driver and the running kernel: "installed" when it is built and
+	// installed for it, "" when DKMS has nothing for it.
+	Built  string   `json:"built,omitempty"`
+	Loaded []string `json:"loaded"`
+	Bound  []Bound  `json:"bound"`
+}
+
+// Group is the account's membership of the group the driver's udev rules give the devices to.
+type Group struct {
+	Name    string `json:"name"`
+	Exists  bool   `json:"exists"`
+	Account bool   `json:"account_in_group"`
+	// Manager is whether the account's running service manager has the group. It took its groups when
+	// it started, at the account's first login, and the daemon runs under it.
+	Manager *bool `json:"service_manager_has_it,omitempty"`
+}
+
+// Device is one device as the daemon sees it. Its serial is not answered.
+type Device struct {
+	Name     string   `json:"name"`
+	Type     string   `json:"type,omitempty"`
+	Firmware string   `json:"firmware,omitempty"`
+	Battery  *float64 `json:"battery_percent,omitempty"`
+	Charging *bool    `json:"charging,omitempty"`
+}
+
+// Daemon is the account's daemon.
+type Daemon struct {
+	Active  string `json:"unit_active"`
+	Enabled string `json:"unit_enabled"`
+	Running []Proc `json:"running"`
+	// StartedBy is what starts it: D-Bus activation of org.razer, through its unit.
+	StartedBy  string   `json:"started_by"`
+	Version    string   `json:"version,omitempty"`
+	Unanswered string   `json:"unanswered,omitempty"`
+	LastWords  []string `json:"last_words,omitempty"`
+}
+
+// StatusAnswer is what openrazer_status answers.
+type StatusAnswer struct {
+	Installed map[string]string `json:"installed"`
+	Driver    Driver            `json:"driver"`
+	Group     Group             `json:"group"`
+	Daemon    Daemon            `json:"daemon"`
+	Devices   []Device          `json:"devices"`
+	Notes     []string          `json:"notes,omitempty"`
+}
+
+// busCall asks the daemon one question and answers busctl's data.
+func (m *Machine) busCall(path, iface, method string) (json.RawMessage, error) {
+	args := []string{"--user", "--auto-start=no", "--json=short", "call", busName, path, iface, method}
+	o := m.cmd(5*time.Second, m.bus(), "busctl", args...)
+	if err := failed(o, "busctl", args...); err != nil {
+		return nil, err
+	}
+	var doc struct {
+		Data []json.RawMessage `json:"data"`
+	}
+	if err := json.Unmarshal([]byte(o.Stdout), &doc); err != nil || len(doc.Data) != 1 {
+		return nil, fmt.Errorf("the daemon's answer to %s is not busctl's JSON: %q", method, tail(o.Stdout, 200))
+	}
+	return doc.Data[0], nil
+}
+
+func (m *Machine) busString(path, iface, method string) (string, error) {
+	raw, err := m.busCall(path, iface, method)
+	if err != nil {
+		return "", err
+	}
+	var s string
+	if err := json.Unmarshal(raw, &s); err != nil {
+		return "", fmt.Errorf("the daemon's %s is not a string: %w", method, err)
+	}
+	return s, nil
+}
+
+// devices asks the daemon for the devices it holds, and each one's name, type, firmware and battery.
+func (m *Machine) devices() ([]Device, string, error) {
+	version, err := m.busString(busRoot, "razer.daemon", "version")
+	if err != nil {
+		return nil, "", err
+	}
+	raw, err := m.busCall(busRoot, "razer.devices", "getDevices")
+	if err != nil {
+		return nil, version, err
+	}
+	var serials []string
+	if err := json.Unmarshal(raw, &serials); err != nil {
+		return nil, version, fmt.Errorf("the daemon's device list is not a list of names: %w", err)
+	}
+	if len(serials) > mostDevices {
+		serials = serials[:mostDevices]
+	}
+	out := []Device{}
+	for _, serial := range serials {
+		path := busRoot + "/device/" + serial
+		d := Device{}
+		d.Name, _ = m.busString(path, "razer.device.misc", "getDeviceName")
+		d.Type, _ = m.busString(path, "razer.device.misc", "getDeviceType")
+		d.Firmware, _ = m.busString(path, "razer.device.misc", "getFirmware")
+		if raw, err := m.busCall(path, "razer.device.power", "getBattery"); err == nil {
+			var pct float64
+			if json.Unmarshal(raw, &pct) == nil {
+				d.Battery = &pct
+			}
+		}
+		if raw, err := m.busCall(path, "razer.device.power", "isCharging"); err == nil {
+			var on bool
+			if json.Unmarshal(raw, &on) == nil {
+				d.Charging = &on
+			}
+		}
+		if d.Name == "" {
+			d.Name = "(unnamed)"
+		}
+		out = append(out, d)
+	}
+	sort.Slice(out, func(i, j int) bool { return out[i].Name < out[j].Name })
+	return out, version, nil
+}
+
+// driver reads the kernel side: DKMS's state for the running kernel, the loaded modules, and the
+// devices bound to them.
+func (m *Machine) driver() Driver {
+	d := Driver{Kernel: readTrimmed(m.path("/proc/sys/kernel/osrelease")), Loaded: []string{}, Bound: []Bound{}}
+	if d.Kernel != "" {
+		o := m.cmd(0, nil, "dkms", "status", dkmsName, "-k", d.Kernel)
+		for _, l := range strings.Split(o.Stdout, "\n") {
+			if strings.HasPrefix(l, dkmsName+"/") && strings.Contains(l, d.Kernel) {
+				if i := strings.LastIndex(l, ":"); i > 0 {
+					d.Built = strings.TrimSpace(l[i+1:])
+				}
+			}
+		}
+	}
+	for _, k := range kernelModules {
+		if exists(m.path(filepath.Join("/sys/module", k))) {
+			d.Loaded = append(d.Loaded, k)
+		}
+	}
+	drivers, _ := os.ReadDir(m.path("/sys/bus/hid/drivers"))
+	seen := map[string]int{}
+	for _, drv := range drivers {
+		if !strings.HasPrefix(drv.Name(), "razer") {
+			continue
+		}
+		entries, _ := os.ReadDir(m.path(filepath.Join("/sys/bus/hid/drivers", drv.Name())))
+		for _, e := range entries {
+			if f := hidID.FindStringSubmatch(e.Name()); f != nil {
+				usb := strings.ToLower(f[1] + ":" + f[2])
+				if i, ok := seen[drv.Name()+" "+usb]; ok {
+					d.Bound[i].Interfaces++
+					continue
+				}
+				seen[drv.Name()+" "+usb] = len(d.Bound)
+				d.Bound = append(d.Bound, Bound{USB: usb, Driver: drv.Name(), Interfaces: 1})
+			}
+		}
+	}
+	return d
+}
+
+// account is the operator account's name, from the user database by uid.
+func (m *Machine) account() string {
+	raw, _ := readBounded(m.path("/etc/passwd"))
+	for _, l := range strings.Split(string(raw), "\n") {
+		f := strings.Split(l, ":")
+		if len(f) > 2 && f[2] == strconv.Itoa(m.UID) {
+			return f[0]
+		}
+	}
+	return ""
+}
+
+// groupOf reads one group's gid and members from the group file.
+func (m *Machine) groupOf(name string) (gid int, members []string, found bool) {
+	raw, _ := readBounded(m.path("/etc/group"))
+	for _, l := range strings.Split(string(raw), "\n") {
+		f := strings.Split(l, ":")
+		if len(f) == 4 && f[0] == name {
+			gid, _ = strconv.Atoi(f[2])
+			for _, who := range strings.Split(f[3], ",") {
+				if who = strings.TrimSpace(who); who != "" {
+					members = append(members, who)
+				}
+			}
+			return gid, members, true
+		}
+	}
+	return 0, nil, false
+}
+
+func contains(list []string, s string) bool {
+	for _, x := range list {
+		if x == s {
+			return true
+		}
+	}
+	return false
+}
+
+// managerGroups are the supplementary groups of the account's own service manager; ok is false when
+// it does not run.
+func (m *Machine) managerGroups() (groups []int, ok bool) {
+	for _, p := range m.procs("systemd") {
+		dir := m.path(filepath.Join("/proc", strconv.Itoa(p.PID)))
+		if !strings.Contains(readTrimmed(filepath.Join(dir, "cgroup")), fmt.Sprintf("user@%d.service", m.UID)) {
+			continue
+		}
+		for _, l := range strings.Split(readTrimmed(filepath.Join(dir, "status")), "\n") {
+			if f := strings.Fields(l); len(f) > 0 && f[0] == "Groups:" {
+				for _, g := range f[1:] {
+					if n, err := strconv.Atoi(g); err == nil {
+						groups = append(groups, n)
+					}
+				}
+			}
+		}
+		return groups, true
+	}
+	return nil, false
+}
+
+func (m *Machine) group() Group {
+	g := Group{Name: group}
+	gid, members, found := m.groupOf(group)
+	if !found {
+		return g
+	}
+	g.Exists = true
+	g.Account = contains(members, m.account())
+	if in, ok := m.managerGroups(); ok {
+		has := false
+		for _, n := range in {
+			has = has || n == gid
+		}
+		g.Manager = &has
+	}
+	return g
+}
+
+// unit answers the daemon's unit's active and enabled states in the account's service manager.
+func (m *Machine) unit() (active, enabled string) {
+	word := func(verb string) string {
+		o := m.cmd(5*time.Second, m.bus(), "systemctl", "--user", verb, daemonUnit)
+		if o.Err != nil {
+			return "unknown"
+		}
+		if w := strings.TrimSpace(o.Stdout); w != "" {
+			return strings.Fields(w)[0]
+		}
+		return "unknown"
+	}
+	return word("is-active"), word("is-enabled")
+}
+
+// lastWords are the daemon's last lines in the account's journal, for a unit that failed: its critical
+// and error lines when it wrote any (the reason, not the traceback of its exit), else the last lines.
+func (m *Machine) lastWords() []string {
+	o := m.cmd(5*time.Second, m.bus(), "journalctl", "--user", "-u", daemonUnit, "-n", "20", "-o", "cat", "--no-pager")
+	var all, said []string
+	seen := map[string]bool{}
+	for _, l := range strings.Split(o.Stdout, "\n") {
+		if l = strings.TrimSpace(l); l == "" {
+			continue
+		}
+		l = tail(stamp.ReplaceAllString(l, ""), 300)
+		all = append(all, l)
+		if (strings.Contains(l, "CRITICAL") || strings.Contains(l, "ERROR")) && !seen[l] {
+			seen[l] = true
+			said = append(said, l)
+		}
+	}
+	if len(said) > 0 {
+		return said
+	}
+	return lastOf(all, 4)
+}
+
+func (m *Machine) daemon() (Daemon, []Device) {
+	d := Daemon{Running: m.procs(daemonComm), StartedBy: "D-Bus activation of " + busName + " through " + daemonUnit}
+	if d.Running == nil {
+		d.Running = []Proc{}
+	}
+	if !exists(m.path(activation)) {
+		d.StartedBy = "nothing: the package's activation file " + activation + " is missing"
+	}
+	d.Active, d.Enabled = m.unit()
+	if d.Active == "failed" {
+		d.LastWords = m.lastWords()
+	}
+	devices := []Device{}
+	if len(d.Running) == 0 {
+		d.Unanswered = "the daemon is not running (asked without starting it)"
+		return d, devices
+	}
+	got, version, err := m.devices()
+	d.Version = version
+	if err != nil {
+		d.Unanswered = err.Error()
+		return d, devices
+	}
+	return d, got
+}
+
+// Status reads the whole stack.
+func (m *Machine) Status() (StatusAnswer, error) {
+	s := StatusAnswer{Installed: map[string]string{}, Driver: m.driver(), Group: m.group()}
+	for _, p := range packages {
+		v, err := m.installed(p)
+		if err != nil {
+			return s, err
+		}
+		s.Installed[p] = v
+	}
+	s.Daemon, s.Devices = m.daemon()
+	if _, members, ok := m.groupOf("plugdev"); ok && contains(members, m.account()) {
+		s.Notes = append(s.Notes, "the account is in plugdev, which this openrazer does not use: its udev rules "+
+			"give the devices to the openrazer group. Other devices' rules may use plugdev; the module leaves it")
+	}
+	return s, nil
+}
+
+// RestartAnswer is what openrazer_restart answers.
+type RestartAnswer struct {
+	Active  string   `json:"unit_active"`
+	Running []Proc   `json:"running"`
+	Version string   `json:"version,omitempty"`
+	Devices []Device `json:"devices"`
+}
+
+// Restart restarts the daemon's unit in the account's service manager and waits for it to answer.
+func (m *Machine) Restart() (RestartAnswer, error) {
+	a := RestartAnswer{Devices: []Device{}}
+	args := []string{"--user", "restart", daemonUnit}
+	if err := failed(m.cmd(15*time.Second, m.bus(), "systemctl", args...), "systemctl", args...); err != nil {
+		words := m.lastWords()
+		return a, fmt.Errorf("the daemon did not start: %v. Its last words: %s. See openrazer_check", err, strings.Join(words, " | "))
+	}
+	a.Active, _ = m.unit()
+	a.Running = m.waitFor(daemonComm, 4*time.Second)
+	devices, version, err := m.devices()
+	a.Version = version
+	if err != nil {
+		return a, fmt.Errorf("the daemon started but does not answer: %v", err)
+	}
+	a.Devices = devices
+	return a, nil
+}
+
+// CheckAnswer is what openrazer_check answers.
+type CheckAnswer struct {
+	OK       bool      `json:"ok"`
+	Findings []Finding `json:"findings"`
+	Starts   []string  `json:"starts"`
+}
+
+// Check verifies the stack from the packages to the devices the daemon sees.
+func (m *Machine) Check() (CheckAnswer, error) {
+	a := CheckAnswer{Findings: []Finding{}, Starts: []string{}}
+	add := func(what, do string) { a.Findings = append(a.Findings, Finding{what, do}) }
+	for _, p := range packages {
+		v, err := m.installed(p)
+		if err != nil {
+			return a, err
+		}
+		if v == "" {
+			add("the package "+p+" is not installed", "push the module to the node")
+		}
+	}
+
+	d := m.driver()
+	switch {
+	case d.Kernel == "":
+		add("the running kernel's release is unreadable", "")
+	case d.Built != "installed":
+		add("the driver is not built for the running kernel "+d.Kernel+" (DKMS: "+orNone(d.Built)+")",
+			"install the headers of the running kernel (linux-headers), then `sudo dkms autoinstall`; or reboot into the kernel it was built for")
+	}
+	if len(d.Bound) == 0 {
+		add("no Razer device is bound to the driver", "plug the device in; if it is plugged in, openrazer_status shows which driver modules are loaded")
+	}
+	if len(d.Loaded) == 0 && d.Built == "installed" {
+		add("none of the driver's modules is loaded", "plug the device in, which loads its module, or `sudo modprobe razermouse` (razerkbd, razerkraken, razeraccessory)")
+	}
+
+	g := m.group()
+	switch {
+	case !g.Exists:
+		add("the group openrazer does not exist", "it comes with openrazer-driver-dkms (sysusers): reinstall it, or `sudo systemd-sysusers`")
+	case !g.Account:
+		add("the account is not in the openrazer group: the daemon refuses to start, and the devices' files are the group's",
+			"`sudo gpasswd -a $USER openrazer`, then log out of every session (or reboot)")
+	case g.Manager != nil && !*g.Manager:
+		add("the account is in the openrazer group, but its running service manager started before it was",
+			"log out of every session (or reboot), so the service manager starts again with the group")
+	}
+
+	if exists(m.path(activation)) {
+		a.Starts = append(a.Starts, "D-Bus activation: "+busName+" through "+daemonUnit)
+	} else {
+		add("the package's activation file "+activation+" is missing: nothing starts the daemon", "reinstall openrazer-daemon")
+	}
+	for _, l := range m.i3Starts("openrazer-daemon") {
+		a.Starts = append(a.Starts, "window manager: "+l)
+		add("a second start: "+l, "remove the line; D-Bus activation starts the daemon when a client asks")
+	}
+
+	daemon, devices := m.daemon()
+	switch {
+	case len(daemon.Running) == 0 && daemon.Active == "failed":
+		add("the daemon failed at its last start: "+strings.Join(lastOf(daemon.LastWords, 2), " | "), "fix what it says, then openrazer_restart")
+	case len(daemon.Running) == 0:
+		add("the daemon is not running", "openrazer_restart; at login the tray's helper asks for it, which starts it")
+	case len(daemon.Running) > 1:
+		add(fmt.Sprintf("%d daemons run", len(daemon.Running)), "openrazer_restart ends them and starts one, from its unit")
+	default:
+		if in := daemon.Running[0].StartedIn; in != daemonUnit {
+			add("the daemon runs outside its unit (in "+in+"): started by hand or by a second start", "openrazer_restart")
+		}
+	}
+	if daemon.Unanswered != "" && len(daemon.Running) > 0 {
+		add("the daemon does not answer: "+daemon.Unanswered, "openrazer_restart")
+	}
+	if len(daemon.Running) > 0 && daemon.Unanswered == "" && len(devices) < len(d.Bound) {
+		add(fmt.Sprintf("the driver holds %d device(s) and the daemon sees %d", len(d.Bound), len(devices)), "openrazer_restart")
+	}
+	a.OK = len(a.Findings) == 0
+	return a, nil
+}
+
+func orNone(s string) string {
+	if s == "" {
+		return "nothing for it"
+	}
+	return s
+}
+
+func lastOf(lines []string, n int) []string {
+	if len(lines) <= n {
+		return lines
+	}
+	return lines[len(lines)-n:]
+}

modules/openrazer/cmd/openrazer-tools/openrazer_test.go

@@ -0,0 +1,185 @@
+package main
+
+import (
+	"encoding/json"
+	"strings"
+	"testing"
+)
+
+const serial = "PM2148H00000001"
+
+// newStack is a machine with the stack as it should be: built and loaded, a mouse bound on three
+// interfaces, the account in the group (and its service manager with it), the daemon running from its
+// unit and answering. member and running take parts of it away.
+func newStack(t *testing.T, member, running bool) *fake {
+	f := newFake(t)
+	f.write("/proc/sys/kernel/osrelease", "7.2.8-arch1-2\n")
+	f.write("/sys/module/razermouse/refcnt", "0\n")
+	for _, i := range []string{"0004", "0005", "0006"} {
+		f.write("/sys/bus/hid/drivers/razermouse/0003:1532:00AB."+i+"/device_type", "")
+	}
+	f.write("/sys/bus/hid/drivers/razermouse/bind", "")
+	f.write("/etc/passwd", "root:x:0:0::/root:/bin/sh\noperator:x:1000:1000::/home/operator:/bin/zsh\n")
+	members := "operator"
+	if !member {
+		members = ""
+	}
+	f.write("/etc/group", "plugdev:x:970:operator\nopenrazer:x:958:"+members+"\n")
+	f.write(activation, "[D-BUS Service]\nName=org.razer\nSystemdService=openrazer-daemon.service\n")
+	f.proc(3596, 1000, "systemd", []string{"/usr/lib/systemd/systemd", "--user"}, "user@1000.service/init.scope")
+	groups := "970 958"
+	if !member {
+		groups = "970"
+	}
+	f.write("/proc/3596/status", "Name:\tsystemd\nUid:\t1000\t1000\t1000\t1000\nGroups:\t"+groups+"\n")
+	if running {
+		f.proc(4269, 1000, daemonComm, []string{"openrazer-daemon", "-F"}, "user@1000.service/app.slice/"+daemonUnit)
+	}
+	f.answer = func(name string, args []string) Output {
+		call := name + " " + strings.Join(args, " ")
+		switch {
+		case name == "pacman":
+			return Output{Stdout: args[1] + " 3.12.4-1\n"}
+		case name == "dkms":
+			return Output{Stdout: "openrazer-driver/3.12.4, 7.2.8-arch1-2, x86_64: installed\n"}
+		case name == "systemctl" && strings.Contains(call, "is-active"):
+			if running {
+				return Output{Stdout: "active\n"}
+			}
+			return Output{Stdout: "failed\n", Code: 3}
+		case name == "systemctl" && strings.Contains(call, "is-enabled"):
+			return Output{Stdout: "disabled\n", Code: 1}
+		case name == "journalctl":
+			return Output{Stdout: "Starting daemon.\n2026-10-04 16:26:21 | razer | CRITICAL | User is not a member of the openrazer group\n" +
+				"Traceback (most recent call last):\n2026-10-04 16:26:22 | razer | CRITICAL | User is not a member of the openrazer group\nSystemExit: 0\n"}
+		case name == "busctl" && !running:
+			return Output{Code: 1, Stderr: "Call failed: The name is not activatable"}
+		case strings.HasSuffix(call, " version"):
+			return Output{Stdout: `{"type":"s","data":["3.12.4"]}`}
+		case strings.HasSuffix(call, " getDevices"):
+			return Output{Stdout: `{"type":"as","data":[["` + serial + `"]]}`}
+		case strings.HasSuffix(call, " getDeviceName"):
+			return Output{Stdout: `{"type":"s","data":["Razer Basilisk V3 Pro"]}`}
+		case strings.HasSuffix(call, " getDeviceType"):
+			return Output{Stdout: `{"type":"s","data":["mouse"]}`}
+		case strings.HasSuffix(call, " getFirmware"):
+			return Output{Stdout: `{"type":"s","data":["v1.04"]}`}
+		case strings.HasSuffix(call, " getBattery"):
+			return Output{Stdout: `{"type":"d","data":[85.0]}`}
+		case strings.HasSuffix(call, " isCharging"):
+			return Output{Code: 1, Stderr: "Unknown method"}
+		}
+		return Output{}
+	}
+	return f
+}
+
+func TestStatusReadsTheDriverTheGroupAndTheDaemonWithoutStartingIt(t *testing.T) {
+	f := newStack(t, true, true)
+	s, err := f.Status()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if s.Installed["openrazer-daemon"] != "3.12.4-1" || s.Driver.Built != "installed" || strings.Join(s.Driver.Loaded, ",") != "razermouse" ||
+		len(s.Driver.Bound) != 1 || s.Driver.Bound[0] != (Bound{USB: "1532:00ab", Driver: "razermouse", Interfaces: 3}) {
+		t.Fatalf("%+v", s)
+	}
+	if !s.Group.Exists || !s.Group.Account || s.Group.Manager == nil || !*s.Group.Manager {
+		t.Fatalf("%+v", s.Group)
+	}
+	if s.Daemon.Version != "3.12.4" || len(s.Daemon.Running) != 1 || len(s.Devices) != 1 {
+		t.Fatalf("%+v %+v", s.Daemon, s.Devices)
+	}
+	d := s.Devices[0]
+	if d.Name != "Razer Basilisk V3 Pro" || d.Type != "mouse" || d.Battery == nil || *d.Battery != 85 || d.Charging != nil {
+		t.Fatalf("%+v", d)
+	}
+	if len(s.Notes) != 1 || !strings.Contains(s.Notes[0], "plugdev") {
+		t.Fatalf("%v", s.Notes)
+	}
+	for _, c := range f.calls {
+		if strings.HasPrefix(c, "busctl") && !strings.Contains(c, "--auto-start=no") {
+			t.Fatalf("a bus call that could start the daemon: %s", c)
+		}
+	}
+	raw, _ := json.Marshal(s)
+	if strings.Contains(string(raw), serial) {
+		t.Fatal("the answer carries a device's serial")
+	}
+
+	stopped := newStack(t, false, false)
+	s, _ = stopped.Status()
+	if s.Group.Account || s.Group.Manager == nil || *s.Group.Manager || s.Daemon.Active != "failed" || stopped.called("busctl") {
+		t.Fatalf("%+v %q", s, stopped.calls)
+	}
+	if len(s.Daemon.LastWords) != 1 || s.Daemon.LastWords[0] != "razer | CRITICAL | User is not a member of the openrazer group" {
+		t.Fatalf("the reason, once, not the traceback: %q", s.Daemon.LastWords)
+	}
+}
+
+func TestCheckPassesTheWholeStackAndNamesWhatIsMissing(t *testing.T) {
+	f := newStack(t, true, true)
+	c, err := f.Check()
+	if err != nil || !c.OK || len(c.Starts) != 1 || !strings.HasPrefix(c.Starts[0], "D-Bus activation") {
+		t.Fatalf("%+v %v", c, err)
+	}
+
+	broken := newStack(t, false, false)
+	broken.write("/proc/sys/kernel/osrelease", "7.3.0-arch1-1\n")
+	broken.write(testHome+"/.config/i3/config", "exec --no-startup-id openrazer-daemon\n")
+	c, _ = broken.Check()
+	var all []string
+	for _, x := range c.Findings {
+		all = append(all, x.What+" => "+x.Do)
+	}
+	got := strings.Join(all, "\n")
+	for _, want := range []string{"not built for the running kernel 7.3.0-arch1-1", "not in the openrazer group", "gpasswd -a $USER openrazer",
+		"a second start: ~/.config/i3/config:1", "failed at its last start: razer | CRITICAL | User is not a member"} {
+		if !strings.Contains(got, want) {
+			t.Errorf("no finding %q in\n%s", want, got)
+		}
+	}
+}
+
+func TestAGroupAddedAfterLoginIsNamedAsTheServiceManagers(t *testing.T) {
+	f := newStack(t, true, true)
+	f.write("/proc/3596/status", "Name:\tsystemd\nUid:\t1000\t1000\t1000\t1000\nGroups:\t970\n")
+	c, _ := f.Check()
+	if c.OK || len(c.Findings) != 1 || !strings.Contains(c.Findings[0].What, "service manager started before") {
+		t.Fatalf("%+v", c)
+	}
+}
+
+func TestADaemonOutsideItsUnitOrSeeingFewerDevicesIsAFinding(t *testing.T) {
+	f := newStack(t, true, true)
+	f.write("/proc/4269/cgroup", "0::/user.slice/user-1000.slice/session-c1.scope\n")
+	f.write("/sys/bus/hid/drivers/razerkbd/0003:1532:0099.0001/x", "")
+	c, _ := f.Check()
+	var all []string
+	for _, x := range c.Findings {
+		all = append(all, x.What)
+	}
+	got := strings.Join(all, "\n")
+	if !strings.Contains(got, "outside its unit (in session-c1.scope)") || !strings.Contains(got, "holds 2 device(s) and the daemon sees 1") {
+		t.Fatalf("%s", got)
+	}
+}
+
+func TestRestartGoesThroughTheUnitAndSaysWhyItFailed(t *testing.T) {
+	f := newStack(t, true, true)
+	a, err := f.Restart()
+	if err != nil || a.Version != "3.12.4" || len(a.Devices) != 1 || !f.called("systemctl --user restart "+daemonUnit) {
+		t.Fatalf("%+v %v %q", a, err, f.calls)
+	}
+	failing := newStack(t, false, false)
+	inner := failing.answer
+	failing.answer = func(name string, args []string) Output {
+		if name == "systemctl" && len(args) > 1 && args[1] == "restart" {
+			return Output{Code: 1, Stderr: "Job for openrazer-daemon.service failed"}
+		}
+		return inner(name, args)
+	}
+	if _, err := failing.Restart(); err == nil || !strings.Contains(err.Error(), "not a member of the openrazer group") {
+		t.Fatalf("%v", err)
+	}
+}

modules/openrazer/go.mod

@@ -0,0 +1,5 @@
+module openrazer
+
+go 1.22
+
+require git.novox.be/novox/mesh-sdk/go v0.1.7

modules/openrazer/go.sum

@@ -0,0 +1,2 @@
+git.novox.be/novox/mesh-sdk/go v0.1.7 h1:C0sTQmtTiyYH7bnqZb7PusXnqA37gKuT7Nqjn9gG47w=
+git.novox.be/novox/mesh-sdk/go v0.1.7/go.mod h1:GFuZUElBZ9A++mxgIKo97aXXo+kV0uJ/UkbhQPPIbrY=

modules/openrazer/module.json

@@ -0,0 +1,44 @@
+{
+  "module": "openrazer",
+  "version": "1",
+  "capabilities": [
+    "package-manager"
+  ],
+  "tools": [
+    "openrazer_status",
+    "openrazer_restart",
+    "openrazer_check"
+  ],
+  "resources": [
+    {
+      "id": "driver",
+      "type": "package",
+      "package": "openrazer-driver-dkms"
+    },
+    {
+      "id": "daemon",
+      "type": "package",
+      "package": "openrazer-daemon"
+    },
+    {
+      "id": "library",
+      "type": "package",
+      "package": "python-openrazer"
+    }
+  ],
+  "build": {
+    "artifacts": [
+      {
+        "name": "tools",
+        "kind": "bundle",
+        "language": "go",
+        "system": "arch",
+        "from": "cmd/openrazer-tools",
+        "binary": "openrazer-tools",
+        "loads": [
+          "openrazer-tools"
+        ]
+      }
+    ]
+  }
+}

modules/polychromatic/README.md

@@ -0,0 +1,96 @@
+# polychromatic
+
+The Razer peripherals' tray on the workstations, as a module (novox/hq ADR 0208). It requires
+`x11-display`, so it is assigned only where a display server is held on the same machine. The driver
+and the daemon it drives are the `openrazer` module's.
+
+## Owns
+
+| what | where |
+|---|---|
+| the tray's one start | a contribution to `node-display-session` (ADR 0212): `exec --no-startup-id polychromatic-tray-applet`, placed by the `i3` module among the other modules' lines |
+
+Nothing else. It declares no package, holds no seat and writes no file.
+
+- **The application is kept as found.** `polychromatic` (0.9.8) is not in the official repositories:
+  on both workstations it is a foreign (AUR) package, installed explicitly. The host installs from the
+  official repositories only, so the module cannot declare it. ADR 0205's pinned archive does not fit
+  either: it is a Qt application with a helper, a tray and a controller, not a set of plain files. Like
+  `snapd` and the laptop's `triggerhappy`, it waits for the mesh's package repository (research 027
+  question 1, option P2). Until then a fresh workstation installs it by hand, and
+  `polychromatic_check` says when it is missing.
+- **Its dependencies are the `openrazer` module's** (`python-openrazer`, the daemon, the driver). The
+  tray brings them when installed by hand; the module does not declare them twice.
+- **The application's settings stay the operator's.** `~/.config/polychromatic/` (preferences,
+  presets, effects, device states) is the application's own, rewritten by it. The tools read only the
+  tray's two keys of `preferences.json`.
+
+## How it starts: the module's window-manager line, and nothing else
+
+The tray had **two starts** on both workstations:
+
+1. the window-manager line `exec --no-startup-id polychromatic-tray-applet`, in the `i3` module's
+   section *Until their modules carry them*;
+2. the package's XDG autostart entry `polychromatic-autostart.desktop`, which `dex` runs at login. It
+   runs `polychromatic-helper --autostart`, which waits for the daemon, resumes each device's
+   software effect, and **starts the tray too while the application's setting *Start the tray applet
+   when I log on* is ticked**. It is ticked on both.
+
+The tray takes a lock file at its start and stops an earlier instance, so two starts end as one tray,
+in a race. On the laptop both ran at the login of 2026-10-04 16:26, and one tray was left; which
+start it came from is not recorded anywhere. On the desktop only the window-manager line ran (that
+session began before `dex` was installed).
+
+**This module takes over the window-manager line as its contribution**, and the `i3` module drops it
+in the same change. That line is the tray's one start:
+
+- it starts the tray with the session, once (`exec`, so a reload of i3 starts nothing);
+- it is the mesh's, so it is in the composed configuration only where the module is assigned.
+
+**The helper stays**, for its other work: the effects it resumes at login. The package's entry is not
+the module's to hide, and hiding it would need a file in the account's autostart directory. So the
+operator unticks the tray setting once (migration, below), and `polychromatic_check` names the
+helper's tray start as a second start for as long as the setting is ticked. The module never writes
+the setting: the application rewrites its preferences file itself.
+
+## Tools
+
+They are served by the node's runtime as the operator account (ADR 0175).
+
+| tool | does |
+|---|---|
+| `polychromatic_status` (r) | <ul><li>whether the tray runs: pid, since, and the scope or unit it runs in</li><li>the installed version, and that it is from outside the official repositories</li><li>what starts it: the window-manager lines, and the helper while the setting is on</li><li>the helper's entry, and the tray setting with its delay</li><li>whether the openrazer daemon answers, and how many devices it has (asked with `--auto-start=no`: never starts it)</li></ul> |
+| `polychromatic_restart` (a) | asks the tray to end (SIGTERM), forces it after 5 s, and starts `polychromatic-tray-applet` in the operator's session as a transient user unit `mesh-polychromatic-tray`, so it outlives the tools runtime. Refused plainly when nobody is logged in to the desktop |
+| `polychromatic_check` (r) | <ul><li>the package is installed</li><li>exactly one start: one window-manager line; the helper does not start the tray too; no autostart entry of the account for it</li><li>one tray runs in a desktop session</li><li>the openrazer daemon answers</li></ul>Each finding says what to do |
+
+The kernel keeps 15 characters of a command name, and `polychromatic-tray-applet` and this bundle's
+`polychromatic-tools` share them. The tools match the tray by its full program name, so they never
+count or end themselves.
+
+## What changes when it is assigned
+
+| | laptop | desktop |
+|---|---|---|
+| package | none: `polychromatic` 0.9.8, explicit, foreign | the same |
+| `~/.config/i3/config` | the tray's line moves from the `i3` module's section to this module's contribution: the same line, and i3's reload starts nothing | the same |
+| tray | none: one runs, left by the two starts' race | none: one runs, from the predecessor's window-manager line (a child of i3, since the session of 2026-10-04 16:00, before `dex` ran) |
+
+## Migration (ADR 0182)
+
+On each workstation, once: in Polychromatic, **untick Preferences → Tray → *Start the tray applet
+when I log on***. From the next login the module's line is the tray's one start, and
+`polychromatic_check` answers `ok` once the daemon answers too (the `openrazer` module's migration).
+
+## Leaves as found
+
+- `~/.config/polychromatic/`: preferences, presets, custom effects, device states.
+- `/etc/xdg/autostart/polychromatic-autostart.desktop`, the package's.
+- The package itself, installed by hand.
+
+## Relies on
+
+- **The `openrazer` module** for the daemon and the driver. The tray without them shows no devices.
+  `polychromatic_check` reports it.
+- **The `i3` module** to place the contribution (ADR 0212 §4: the contribution depends on
+  `node-display-session`), and to run `dex` for the helper.
+- A display server on the same machine (`x11-display`, ADR 0208 §3).

modules/polychromatic/cmd/polychromatic-tools/copies_test.go

@@ -0,0 +1,37 @@
+package main
+
+// The desktop applications whose bundles carry desktop.go. Each builds alone, so each has its own copy;
+// this test, itself one of the copied files, holds them to one text wherever the siblings are present.
+
+import (
+	"bytes"
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+var carriers = []string{"blueman", "forticlient", "nextcloud-client", "nm-applet", "openrazer", "polychromatic", "slack"}
+
+func TestEveryDesktopApplicationCarriesTheSameCopy(t *testing.T) {
+	compared := 0
+	for _, module := range carriers {
+		dir := filepath.Join("..", "..", "..", module, "cmd", module+"-tools")
+		if _, err := os.Stat(dir); err != nil {
+			continue
+		}
+		for _, f := range []string{"desktop.go", "desktop_test.go", "copies_test.go"} {
+			mine, err := os.ReadFile(f)
+			if err != nil {
+				t.Fatal(err)
+			}
+			theirs, err := os.ReadFile(filepath.Join(dir, f))
+			if err != nil || !bytes.Equal(mine, theirs) {
+				t.Errorf("%s's copy of %s differs from this one: change every copy together", module, f)
+			}
+		}
+		compared++
+	}
+	if compared == 0 {
+		t.Log("no sibling copies beside this module")
+	}
+}

modules/polychromatic/cmd/polychromatic-tools/desktop.go

@@ -0,0 +1,601 @@
+package main
+
+// desktop.go is the same file in every desktop application's bundle (copies_test.go names them and
+// holds them to one text): a tray application of the operator's graphical session, seen from the
+// node's tool runtime (novox/hq ADR 0208).
+//
+// The runtime is a system service running as the operator account (ADR 0175): it has the account's
+// uid and none of the session's environment. A tool that starts something on the desktop finds the
+// session from a process of the account that carries DISPLAY (the window manager first), and starts
+// the program under the account's own service manager with `systemd-run --user`, never as its own
+// child: the runtime's unit is a cgroup that is emptied whenever the runtime restarts.
+//
+// Everything a tool touches goes through a Machine: its filesystem root, its commands (a Runner) and
+// its signals are injected, so the tests run against a fake /proc and a fake home.
+//
+// Bounds: one command gets at most CallTimeout (below the runtime's 30 s call limit) and is ended
+// with everything it started when it takes longer; each stream is kept to MostOutput; a file is read
+// to at most MostRead.
+
+import (
+	"bufio"
+	"bytes"
+	"context"
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"sort"
+	"strconv"
+	"strings"
+	"syscall"
+	"time"
+)
+
+// Bounds every command and read is held to.
+const (
+	CallTimeout = 10 * time.Second
+	MostOutput  = 256 << 10
+	MostRead    = 16 << 20
+)
+
+// Output is what a command did.
+type Output struct {
+	Stdout string
+	Stderr string
+	Code   int
+	// Err is why it did not run to an answer: not installed, ended on its timeout, or the spawn error.
+	Err error
+	Cut bool
+}
+
+// ErrNotInstalled and ErrTimedOut are what a Runner answers in Output.Err.
+var (
+	ErrNotInstalled = errors.New("not installed")
+	ErrTimedOut     = errors.New("timed out")
+	// ErrNoSession is answered by a tool that needs the desktop when nobody is logged in to it.
+	ErrNoSession = errors.New("no graphical session")
+)
+
+// Runner runs one command with extra environment, within the context's deadline. Tests replace it.
+type Runner func(ctx context.Context, env []string, name string, args ...string) Output
+
+// Machine is what the tools read and act on.
+type Machine struct {
+	Root    string // "" on the machine; a fake root in tests
+	Home    string // the operator's home, as the machine names it
+	UID     int
+	Run     Runner
+	Kill    func(pid int, sig syscall.Signal) error
+	Sleep   func(time.Duration)
+	Now     func() time.Time
+	Timeout time.Duration
+}
+
+// NewMachine is the machine the bundle runs on.
+func NewMachine() *Machine {
+	return &Machine{Home: operatorHome(), UID: os.Getuid(), Run: execRun, Kill: syscall.Kill,
+		Sleep: time.Sleep, Now: time.Now, Timeout: CallTimeout}
+}
+
+// operatorHome is the account's home: what the runtime was told, else the process's own.
+func operatorHome() string {
+	if h := strings.TrimSpace(os.Getenv("MESH_OPERATOR_HOME")); h != "" {
+		return h
+	}
+	h, _ := os.UserHomeDir()
+	return h
+}
+
+func (m *Machine) path(p string) string { return filepath.Join(m.Root, p) }
+
+// home is a path under the operator's home, on this machine's filesystem.
+func (m *Machine) home(rel ...string) string {
+	return filepath.Join(append([]string{m.Root, m.Home}, rel...)...)
+}
+
+// tilde shows a path under the home as ~/…, so an answer does not carry the account's name.
+func (m *Machine) tilde(p string) string {
+	if m.Home != "" && m.Home != "/" {
+		h := strings.TrimSuffix(m.Home, "/")
+		if p == h {
+			return "~"
+		}
+		if strings.HasPrefix(p, h+"/") {
+			return "~/" + strings.TrimPrefix(p, h+"/")
+		}
+	}
+	return p
+}
+
+// cmd runs a command within the machine's timeout (or a shorter one).
+func (m *Machine) cmd(timeout time.Duration, env []string, name string, args ...string) Output {
+	if timeout <= 0 || timeout > m.Timeout {
+		timeout = m.Timeout
+	}
+	ctx, cancel := context.WithTimeout(context.Background(), timeout)
+	defer cancel()
+	return m.Run(ctx, env, name, args...)
+}
+
+// failed names how a command failed, or answers nil when it ran and exited 0.
+func failed(o Output, name string, args ...string) error {
+	switch {
+	case errors.Is(o.Err, ErrNotInstalled):
+		return fmt.Errorf("%s is not installed on this machine", name)
+	case errors.Is(o.Err, ErrTimedOut):
+		return fmt.Errorf("%s gave no answer in time and was ended", name)
+	case o.Err != nil:
+		return fmt.Errorf("%s did not run: %v", name, o.Err)
+	case o.Code != 0:
+		said := strings.TrimSpace(o.Stderr)
+		if said == "" {
+			said = strings.TrimSpace(o.Stdout)
+		}
+		if said == "" {
+			said = "and said nothing"
+		}
+		return fmt.Errorf("%s %s exited %d: %s", name, strings.Join(args, " "), o.Code, tail(said, 1000))
+	}
+	return nil
+}
+
+func tail(s string, n int) string {
+	if len(s) <= n {
+		return s
+	}
+	return "…" + s[len(s)-n:]
+}
+
+type capped struct {
+	b   bytes.Buffer
+	cut bool
+}
+
+func (c *capped) Write(p []byte) (int, error) {
+	if room := MostOutput - c.b.Len(); room < len(p) {
+		if room > 0 {
+			c.b.Write(p[:room])
+		}
+		c.cut = true
+		return len(p), nil
+	}
+	return c.b.Write(p)
+}
+
+func execRun(ctx context.Context, env []string, name string, args ...string) Output {
+	path, err := exec.LookPath(name)
+	if err != nil {
+		return Output{Code: 127, Err: ErrNotInstalled}
+	}
+	cmd := exec.CommandContext(ctx, path, args...)
+	cmd.Env = append(append(os.Environ(), "LC_ALL=C"), env...)
+	// Its own process group, so that ending it on a timeout ends what it started too.
+	cmd.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
+	cmd.Cancel = func() error {
+		if cmd.Process != nil {
+			_ = syscall.Kill(-cmd.Process.Pid, syscall.SIGKILL)
+		}
+		return nil
+	}
+	cmd.WaitDelay = 2 * time.Second
+	var out, errs capped
+	cmd.Stdout, cmd.Stderr = &out, &errs
+	err = cmd.Run()
+	o := Output{Stdout: out.b.String(), Stderr: errs.b.String(), Cut: out.cut || errs.cut}
+	var exit *exec.ExitError
+	switch {
+	case err == nil:
+	case ctx.Err() == context.DeadlineExceeded:
+		o.Code, o.Err = 124, ErrTimedOut
+	case errors.As(err, &exit):
+		o.Code = exit.ExitCode()
+	default:
+		o.Code, o.Err = 127, err
+	}
+	return o
+}
+
+// readBounded reads a file to at most MostRead bytes.
+func readBounded(path string) ([]byte, error) {
+	f, err := os.Open(path)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+	return io.ReadAll(io.LimitReader(f, MostRead))
+}
+
+// Proc is one process of the account.
+type Proc struct {
+	PID     int    `json:"pid"`
+	Command string `json:"command"`
+	// StartedIn is the unit or scope it runs in: the login session's scope when the session's start
+	// (dex, the window manager) started it, a mesh-… unit when a tool restarted it.
+	StartedIn string `json:"started_in,omitempty"`
+	Since     string `json:"since,omitempty"`
+}
+
+// procs are this account's processes named comm, oldest first.
+func (m *Machine) procs(comm string) []Proc {
+	entries, err := os.ReadDir(m.path("/proc"))
+	if err != nil {
+		return nil
+	}
+	boot := m.bootTime()
+	var out []Proc
+	for _, e := range entries {
+		pid, err := strconv.Atoi(e.Name())
+		if err != nil {
+			continue
+		}
+		dir := m.path(filepath.Join("/proc", e.Name()))
+		if readTrimmed(filepath.Join(dir, "comm")) != comm || m.uidOf(dir) != m.UID {
+			continue
+		}
+		p := Proc{PID: pid, Command: strings.TrimSpace(strings.ReplaceAll(readTrimmed(filepath.Join(dir, "cmdline")), "\x00", " "))}
+		if p.Command == "" {
+			p.Command = comm
+		}
+		if cg := readTrimmed(filepath.Join(dir, "cgroup")); cg != "" {
+			line := strings.Split(cg, "\n")[0]
+			p.StartedIn = filepath.Base(line[strings.LastIndexByte(line, ':')+1:])
+		}
+		if t, ok := startOf(readTrimmed(filepath.Join(dir, "stat")), boot); ok {
+			p.Since = t.UTC().Format(time.RFC3339)
+		}
+		out = append(out, p)
+	}
+	sort.Slice(out, func(i, j int) bool { return out[i].PID < out[j].PID })
+	return out
+}
+
+// procsOf are the account's processes named comm whose program is word. The kernel keeps 15
+// characters of a command name, so a longer name can share them with another program's: this bundle's
+// own binary among them (polychromatic-tools and polychromatic-tray-applet are both polychromatic-t).
+// The program is the first word of the command line, or the second for a script run by its
+// interpreter. An empty word keeps every process named comm.
+func (m *Machine) procsOf(comm, word string) []Proc {
+	var out []Proc
+	for _, p := range m.procs(comm) {
+		f := strings.Fields(p.Command)
+		if word == "" || (len(f) > 0 && filepath.Base(f[0]) == word) || (len(f) > 1 && filepath.Base(f[1]) == word) {
+			out = append(out, p)
+		}
+	}
+	return out
+}
+
+// uidOf is the real uid on a process's status, -1 when unreadable.
+func (m *Machine) uidOf(dir string) int {
+	for _, l := range strings.Split(readTrimmed(filepath.Join(dir, "status")), "\n") {
+		if f := strings.Fields(l); len(f) > 1 && f[0] == "Uid:" {
+			if n, err := strconv.Atoi(f[1]); err == nil {
+				return n
+			}
+		}
+	}
+	return -1
+}
+
+func (m *Machine) bootTime() int64 {
+	for _, l := range strings.Split(readTrimmed(m.path("/proc/stat")), "\n") {
+		if f := strings.Fields(l); len(f) == 2 && f[0] == "btime" {
+			n, _ := strconv.ParseInt(f[1], 10, 64)
+			return n
+		}
+	}
+	return 0
+}
+
+// startOf reads a process's start from its stat line (field 22, in clock ticks of 1/100 s since boot).
+func startOf(stat string, boot int64) (time.Time, bool) {
+	i := strings.LastIndexByte(stat, ')')
+	if i < 0 || boot == 0 {
+		return time.Time{}, false
+	}
+	f := strings.Fields(stat[i+1:])
+	if len(f) < 20 {
+		return time.Time{}, false
+	}
+	ticks, err := strconv.ParseInt(f[19], 10, 64)
+	if err != nil {
+		return time.Time{}, false
+	}
+	return time.Unix(boot+ticks/100, 0), true
+}
+
+func readTrimmed(path string) string {
+	b, err := os.ReadFile(path)
+	if err != nil {
+		return ""
+	}
+	return strings.TrimSpace(string(b))
+}
+
+func exists(path string) bool {
+	_, err := os.Stat(path)
+	return err == nil
+}
+
+// Session is what a tool needs to start something on the operator's desktop.
+type Session struct {
+	Display    string `json:"display"`
+	XAuthority string `json:"xauthority,omitempty"`
+	Bus        string `json:"bus,omitempty"`
+	RuntimeDir string `json:"runtime_dir,omitempty"`
+	From       string `json:"found_in"`
+}
+
+// sessionHolders are the processes whose environment is the session's, best first.
+var sessionHolders = []string{"i3", "sway", "i3bar", "picom", "dunst", "xterm"}
+
+// session finds the account's graphical session, or ErrNoSession saying what it looked at.
+func (m *Machine) session() (Session, error) {
+	entries, _ := os.ReadDir(m.path("/proc"))
+	best, bestRank := -1, len(sessionHolders)+1
+	var env map[string]string
+	var from string
+	for _, e := range entries {
+		pid, err := strconv.Atoi(e.Name())
+		if err != nil {
+			continue
+		}
+		dir := m.path(filepath.Join("/proc", e.Name()))
+		if m.uidOf(dir) != m.UID {
+			continue
+		}
+		raw, err := os.ReadFile(filepath.Join(dir, "environ"))
+		if err != nil {
+			continue
+		}
+		vars := parseEnviron(raw)
+		if vars["DISPLAY"] == "" {
+			continue
+		}
+		comm := readTrimmed(filepath.Join(dir, "comm"))
+		rank := len(sessionHolders)
+		for i, h := range sessionHolders {
+			if h == comm {
+				rank = i
+			}
+		}
+		if rank < bestRank || (rank == bestRank && pid > best) {
+			best, bestRank, env, from = pid, rank, vars, fmt.Sprintf("process %s (pid %d)", comm, pid)
+		}
+	}
+	if env == nil {
+		return Session{}, fmt.Errorf("%w for uid %d on this machine: no process of the account carries DISPLAY. "+
+			"Is anyone logged in to the desktop?", ErrNoSession, m.UID)
+	}
+	s := Session{Display: env["DISPLAY"], XAuthority: env["XAUTHORITY"], Bus: env["DBUS_SESSION_BUS_ADDRESS"],
+		RuntimeDir: env["XDG_RUNTIME_DIR"], From: from}
+	if s.RuntimeDir == "" {
+		s.RuntimeDir = fmt.Sprintf("/run/user/%d", m.UID)
+	}
+	if s.Bus == "" && exists(m.path(filepath.Join(s.RuntimeDir, "bus"))) {
+		s.Bus = "unix:path=" + filepath.Join(s.RuntimeDir, "bus")
+	}
+	return s, nil
+}
+
+// bus is the account's session bus environment, which a logged-in account has with or without a
+// desktop: what a command needs to reach the user's service manager or a bus name.
+func (m *Machine) bus() []string {
+	runtime := fmt.Sprintf("/run/user/%d", m.UID)
+	return []string{"XDG_RUNTIME_DIR=" + runtime, "DBUS_SESSION_BUS_ADDRESS=unix:path=" + runtime + "/bus"}
+}
+
+// Env is the session's variables, for a command that draws or speaks to the desktop.
+func (s Session) Env() []string {
+	var env []string
+	for _, kv := range [][2]string{{"DISPLAY", s.Display}, {"XAUTHORITY", s.XAuthority},
+		{"DBUS_SESSION_BUS_ADDRESS", s.Bus}, {"XDG_RUNTIME_DIR", s.RuntimeDir}} {
+		if kv[1] != "" {
+			env = append(env, kv[0]+"="+kv[1])
+		}
+	}
+	return env
+}
+
+func parseEnviron(raw []byte) map[string]string {
+	env := map[string]string{}
+	for _, kv := range bytes.Split(raw, []byte{0}) {
+		if i := bytes.IndexByte(kv, '='); i > 0 {
+			env[string(kv[:i])] = string(kv[i+1:])
+		}
+	}
+	return env
+}
+
+// detach starts a long-lived program under the account's service manager, as a transient unit that
+// carries the session's display. A unit left by an earlier start under the same name is stopped
+// first, so the fixed name means at most one.
+func (m *Machine) detach(s Session, unit string, argv ...string) error {
+	_ = m.cmd(5*time.Second, s.Env(), "systemctl", "--user", "stop", unit+".service")
+	call := []string{"--user", "--collect", "--quiet", "--unit=" + unit}
+	for _, kv := range [][2]string{{"DISPLAY", s.Display}, {"XAUTHORITY", s.XAuthority}} {
+		if kv[1] != "" {
+			call = append(call, "--setenv="+kv[0]+"="+kv[1])
+		}
+	}
+	call = append(append(call, "--"), argv...)
+	return failed(m.cmd(8*time.Second, s.Env(), "systemd-run", call...), "systemd-run", call...)
+}
+
+// stop ends every process of the account named in comms: SIGTERM, then SIGKILL for what is still
+// there after grace. It answers the pids that ended and those that had to be killed.
+func (m *Machine) stop(grace time.Duration, comms ...string) (ended, killed []int) {
+	var ps []Proc
+	for _, c := range comms {
+		ps = append(ps, m.procs(c)...)
+	}
+	return m.stopProcs(grace, ps)
+}
+
+// stopProcs ends the processes given, as stop does.
+func (m *Machine) stopProcs(grace time.Duration, ps []Proc) (ended, killed []int) {
+	var pids []int
+	for _, p := range ps {
+		if m.Kill(p.PID, syscall.SIGTERM) == nil {
+			pids = append(pids, p.PID)
+		}
+	}
+	alive := func() []int {
+		var left []int
+		for _, pid := range pids {
+			if exists(m.path(filepath.Join("/proc", strconv.Itoa(pid)))) {
+				left = append(left, pid)
+			}
+		}
+		return left
+	}
+	step := 200 * time.Millisecond
+	for waited := time.Duration(0); waited < grace && len(alive()) > 0; waited += step {
+		m.Sleep(step)
+	}
+	left := alive()
+	for _, pid := range left {
+		if m.Kill(pid, syscall.SIGKILL) == nil {
+			killed = append(killed, pid)
+		}
+	}
+	gone := map[int]bool{}
+	for _, pid := range left {
+		gone[pid] = true
+	}
+	for _, pid := range pids {
+		if !gone[pid] {
+			ended = append(ended, pid)
+		}
+	}
+	return ended, killed
+}
+
+// waitFor waits up to d for a process of the account named comm, and answers what it found.
+func (m *Machine) waitFor(comm string, d time.Duration) []Proc { return m.waitForOf(comm, "", d) }
+
+// waitForOf waits up to d for a process of the account named comm whose program is word (procsOf).
+func (m *Machine) waitForOf(comm, word string, d time.Duration) []Proc {
+	step := 250 * time.Millisecond
+	for waited := time.Duration(0); ; waited += step {
+		if p := m.procsOf(comm, word); len(p) > 0 || waited >= d {
+			return p
+		}
+		m.Sleep(step)
+	}
+}
+
+// desktopEntry reads the [Desktop Entry] group of an XDG desktop file; nil when there is none.
+func desktopEntry(path string) map[string]string {
+	raw, err := readBounded(path)
+	if err != nil {
+		return nil
+	}
+	out := map[string]string{}
+	in := false
+	s := bufio.NewScanner(bytes.NewReader(raw))
+	for s.Scan() {
+		l := strings.TrimSpace(s.Text())
+		switch {
+		case strings.HasPrefix(l, "["):
+			in = l == "[Desktop Entry]"
+		case in && l != "" && !strings.HasPrefix(l, "#"):
+			if i := strings.IndexByte(l, '='); i > 0 {
+				out[strings.TrimSpace(l[:i])] = strings.TrimSpace(l[i+1:])
+			}
+		}
+	}
+	return out
+}
+
+// Autostart is what XDG autostart does with one entry: the account's file overrides the system's
+// of the same name, and Hidden=true (or the GNOME switch off) means it is not started.
+type Autostart struct {
+	Entry   string `json:"entry"`
+	From    string `json:"from"`
+	Exec    string `json:"exec,omitempty"`
+	Starts  bool   `json:"starts"`
+	Because string `json:"because,omitempty"`
+}
+
+// autostart resolves one XDG autostart entry by its file name, the account's directory first.
+func (m *Machine) autostart(name string) Autostart {
+	a := Autostart{Entry: name}
+	user := m.home(".config", "autostart", name)
+	system := m.path(filepath.Join("/etc/xdg/autostart", name))
+	var e map[string]string
+	switch {
+	case exists(user):
+		e, a.From = desktopEntry(user), m.tilde(filepath.Join(m.Home, ".config/autostart", name))
+	case exists(system):
+		e, a.From = desktopEntry(system), filepath.Join("/etc/xdg/autostart", name)
+	default:
+		a.Because = "no such entry in ~/.config/autostart or /etc/xdg/autostart"
+		return a
+	}
+	a.Exec = e["Exec"]
+	switch {
+	case strings.EqualFold(e["Hidden"], "true"):
+		a.Because = "Hidden=true"
+	case strings.EqualFold(e["X-GNOME-Autostart-enabled"], "false"):
+		a.Because = "X-GNOME-Autostart-enabled=false"
+	case a.Exec == "":
+		a.Because = "the entry has no Exec"
+	default:
+		a.Starts = true
+	}
+	return a
+}
+
+// i3Starts are the window manager's start-up lines (exec, exec_always) that run a program named
+// word, in the configuration and its config.d: a second start beside an autostart entry.
+func (m *Machine) i3Starts(word string) []string {
+	files := []string{m.home(".config", "i3", "config")}
+	more, _ := filepath.Glob(m.home(".config", "i3", "config.d", "*.conf"))
+	files = append(files, more...)
+	var out []string
+	for _, f := range files {
+		raw, err := readBounded(f)
+		if err != nil {
+			continue
+		}
+		for n, l := range strings.Split(string(raw), "\n") {
+			t := strings.TrimSpace(l)
+			if !strings.HasPrefix(t, "exec ") && !strings.HasPrefix(t, "exec_always ") {
+				continue
+			}
+			for _, w := range strings.Fields(t)[1:] {
+				if filepath.Base(strings.Trim(w, `"'`)) == word {
+					out = append(out, fmt.Sprintf("%s:%d: %s", m.tilde(strings.TrimPrefix(f, m.Root)), n+1, t))
+					break
+				}
+			}
+		}
+	}
+	return out
+}
+
+// installed asks the package manager for one package's version; "" when it is not installed.
+func (m *Machine) installed(pkg string) (string, error) {
+	o := m.cmd(0, nil, "pacman", "-Q", pkg)
+	if o.Err != nil {
+		return "", failed(o, "pacman", "-Q", pkg)
+	}
+	if o.Code != 0 {
+		return "", nil
+	}
+	f := strings.Fields(o.Stdout)
+	if len(f) < 2 {
+		return "", fmt.Errorf("pacman -Q %s answered %q", pkg, o.Stdout)
+	}
+	return f[1], nil
+}
+
+// Finding is one thing a check found wrong, and what to do about it.
+type Finding struct {
+	What string `json:"what"`
+	Do   string `json:"do,omitempty"`
+}

modules/polychromatic/cmd/polychromatic-tools/desktop_test.go

@@ -0,0 +1,219 @@
+package main
+
+// The fake machine the tests run against, and the tests of desktop.go. The same in every desktop
+// application's bundle (copies_test.go).
+
+import (
+	"context"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"sync"
+	"syscall"
+	"testing"
+	"time"
+)
+
+const testHome = "/home/operator"
+
+// fake is a machine with a fake root, a scripted Runner and signals that end fake processes.
+type fake struct {
+	*Machine
+	t      *testing.T
+	mu     sync.Mutex
+	calls  []string
+	answer func(name string, args []string) Output
+	// onStart is run when systemd-run starts something, to let a fake process appear.
+	onStart func(argv []string)
+	// stubborn pids ignore SIGTERM.
+	stubborn map[int]bool
+	signals  []string
+}
+
+func newFake(t *testing.T) *fake {
+	t.Helper()
+	root := t.TempDir()
+	f := &fake{t: t, stubborn: map[int]bool{}}
+	f.Machine = &Machine{Root: root, Home: testHome, UID: 1000, Timeout: CallTimeout,
+		Sleep: func(time.Duration) {}, Now: func() time.Time { return time.Unix(1_800_000_000, 0) }}
+	f.Run = func(_ context.Context, env []string, name string, args ...string) Output {
+		f.mu.Lock()
+		f.calls = append(f.calls, strings.TrimSpace(name+" "+strings.Join(args, " ")))
+		f.mu.Unlock()
+		if name == "systemd-run" && f.onStart != nil {
+			for i, a := range args {
+				if a == "--" {
+					f.onStart(args[i+1:])
+				}
+			}
+		}
+		if f.answer != nil {
+			return f.answer(name, args)
+		}
+		return Output{}
+	}
+	f.Kill = func(pid int, sig syscall.Signal) error {
+		f.signals = append(f.signals, strconv.Itoa(pid)+":"+sig.String())
+		if sig == syscall.SIGKILL || !f.stubborn[pid] {
+			return os.RemoveAll(filepath.Join(root, "proc", strconv.Itoa(pid)))
+		}
+		return nil
+	}
+	f.write("/proc/stat", "cpu 1 2 3\nbtime 1799990000\n")
+	return f
+}
+
+func (f *fake) write(path, content string) {
+	f.t.Helper()
+	p := filepath.Join(f.Root, path)
+	if err := os.MkdirAll(filepath.Dir(p), 0o755); err != nil {
+		f.t.Fatal(err)
+	}
+	if err := os.WriteFile(p, []byte(content), 0o644); err != nil {
+		f.t.Fatal(err)
+	}
+}
+
+// proc adds a process of uid with a command name, argv, cgroup and environment.
+func (f *fake) proc(pid, uid int, comm string, argv []string, cgroup string, env ...string) {
+	d := "/proc/" + strconv.Itoa(pid) + "/"
+	f.write(d+"comm", comm+"\n")
+	f.write(d+"status", "Name:\t"+comm+"\nUid:\t"+strconv.Itoa(uid)+"\t"+strconv.Itoa(uid)+"\t"+strconv.Itoa(uid)+"\t"+strconv.Itoa(uid)+"\n")
+	f.write(d+"cmdline", strings.Join(argv, "\x00")+"\x00")
+	f.write(d+"cgroup", "0::/user.slice/user-"+strconv.Itoa(uid)+".slice/"+cgroup+"\n")
+	f.write(d+"environ", strings.Join(env, "\x00")+"\x00")
+	// starttime (field 22) is 1000 ticks: 10 s after boot.
+	f.write(d+"stat", strconv.Itoa(pid)+" ("+comm+") S 1 1 1 0 -1 0 0 0 0 0 0 0 0 0 20 0 1 0 1000 0 0\n")
+}
+
+func (f *fake) desktopSession() {
+	f.proc(3700, 1000, "i3", []string{"i3"}, "session-c1.scope", "DISPLAY=:1", "XAUTHORITY="+testHome+"/.Xauthority")
+	f.write("/run/user/1000/bus", "")
+}
+
+func (f *fake) called(prefix string) bool {
+	for _, c := range f.calls {
+		if strings.HasPrefix(c, prefix) {
+			return true
+		}
+	}
+	return false
+}
+
+func TestProcessesAreTheAccountsOwnWithWhereAndWhenTheyStarted(t *testing.T) {
+	f := newFake(t)
+	f.proc(10, 1000, "worker", []string{"/usr/bin/worker", "--background"}, "session-c1.scope")
+	f.proc(11, 1001, "worker", []string{"/usr/bin/worker"}, "session-c2.scope")
+	f.proc(12, 1000, "other", []string{"other"}, "x.scope")
+	got := f.procs("worker")
+	if len(got) != 1 || got[0].PID != 10 || got[0].Command != "/usr/bin/worker --background" ||
+		got[0].StartedIn != "session-c1.scope" || got[0].Since != time.Unix(1799990010, 0).UTC().Format(time.RFC3339) {
+		t.Fatalf("%+v", got)
+	}
+}
+
+func TestAProgramIsToldFromAnotherSharingItsCutName(t *testing.T) {
+	f := newFake(t)
+	f.proc(10, 1000, "polychromatic-t", []string{"/usr/bin/python", "/usr/bin/polychromatic-tray-applet"}, "s.scope")
+	f.proc(11, 1000, "polychromatic-t", []string{"polychromatic-tray-applet"}, "s.scope")
+	f.proc(12, 1000, "polychromatic-t", []string{"/usr/lib/mesh/polychromatic-tools"}, "s.scope")
+	if got := f.procsOf("polychromatic-t", "polychromatic-tray-applet"); len(got) != 2 || got[0].PID != 10 || got[1].PID != 11 {
+		t.Fatalf("%+v", got)
+	}
+	if got := f.procsOf("polychromatic-t", ""); len(got) != 3 {
+		t.Fatalf("%+v", got)
+	}
+	ended, _ := f.stopProcs(time.Second, f.procsOf("polychromatic-t", "polychromatic-tray-applet"))
+	if len(ended) != 2 || len(f.procs("polychromatic-t")) != 1 {
+		t.Fatalf("ended %v; the tools' own process must stay", ended)
+	}
+}
+
+func TestTheSessionIsTheWindowManagersAndNoneIsSaidPlainly(t *testing.T) {
+	f := newFake(t)
+	if _, err := f.session(); err == nil || !strings.Contains(err.Error(), "no graphical session") {
+		t.Fatalf("%v", err)
+	}
+	f.proc(50, 1000, "xterm", []string{"xterm"}, "s.scope", "DISPLAY=:9")
+	f.desktopSession()
+	f.proc(60, 1001, "i3", []string{"i3"}, "s.scope", "DISPLAY=:5")
+	s, err := f.session()
+	if err != nil || s.Display != ":1" || s.XAuthority != testHome+"/.Xauthority" || s.Bus != "unix:path=/run/user/1000/bus" ||
+		!strings.Contains(s.From, "i3") {
+		t.Fatalf("%+v %v", s, err)
+	}
+}
+
+func TestStopAsksThenForcesAndDetachStartsUnderTheServiceManager(t *testing.T) {
+	f := newFake(t)
+	f.desktopSession()
+	f.proc(20, 1000, "app", []string{"app"}, "s.scope")
+	f.proc(21, 1000, "app", []string{"app"}, "s.scope")
+	f.stubborn[21] = true
+	ended, killed := f.stop(time.Second, "app")
+	if len(ended) != 1 || ended[0] != 20 || len(killed) != 1 || killed[0] != 21 {
+		t.Fatalf("ended %v killed %v (%v)", ended, killed, f.signals)
+	}
+	s, _ := f.session()
+	if err := f.detach(s, "mesh-app", "/usr/bin/app", "--background"); err != nil {
+		t.Fatal(err)
+	}
+	want := "systemd-run --user --collect --quiet --unit=mesh-app --setenv=DISPLAY=:1 --setenv=XAUTHORITY=" + testHome +
+		"/.Xauthority -- /usr/bin/app --background"
+	if !f.called("systemctl --user stop mesh-app.service") || !f.called(want) {
+		t.Fatalf("%q", f.calls)
+	}
+}
+
+func TestAnAutostartEntryOfTheAccountOverridesTheSystemsAndHiddenStartsNothing(t *testing.T) {
+	f := newFake(t)
+	if a := f.autostart("x.desktop"); a.Starts || a.Because == "" {
+		t.Fatalf("%+v", a)
+	}
+	f.write("/etc/xdg/autostart/x.desktop", "[Desktop Entry]\nExec=x-applet\n[Desktop Action y]\nExec=other\n")
+	if a := f.autostart("x.desktop"); !a.Starts || a.Exec != "x-applet" || a.From != "/etc/xdg/autostart/x.desktop" {
+		t.Fatalf("%+v", a)
+	}
+	f.write(testHome+"/.config/autostart/x.desktop", "[Desktop Entry]\nExec=x-applet\nHidden=true\n")
+	if a := f.autostart("x.desktop"); a.Starts || a.Because != "Hidden=true" || a.From != "~/.config/autostart/x.desktop" {
+		t.Fatalf("%+v", a)
+	}
+}
+
+func TestAWindowManagerStartIsFoundInTheConfigurationAndItsDropIns(t *testing.T) {
+	f := newFake(t)
+	f.write(testHome+"/.config/i3/config", "exec --no-startup-id dex --autostart --environment i3\n# exec app\nbindsym $mod+a exec app\n")
+	f.write(testHome+"/.config/i3/config.d/50-x.conf", "exec_always --no-startup-id /usr/bin/app --flag\n")
+	got := f.i3Starts("app")
+	if len(got) != 1 || got[0] != "~/.config/i3/config.d/50-x.conf:1: exec_always --no-startup-id /usr/bin/app --flag" {
+		t.Fatalf("%q", got)
+	}
+}
+
+func TestACommandThatFailsIsNamed(t *testing.T) {
+	if err := failed(Output{Code: 127, Err: ErrNotInstalled}, "dex"); err == nil || !strings.Contains(err.Error(), "dex is not installed") {
+		t.Fatal(err)
+	}
+	if err := failed(Output{Code: 1, Stderr: "nope"}, "pacman", "-Q", "x"); err == nil || !strings.Contains(err.Error(), "pacman -Q x exited 1: nope") {
+		t.Fatal(err)
+	}
+	if err := failed(Output{}, "true"); err != nil {
+		t.Fatal(err)
+	}
+}
+
+func TestTheRealRunnerBoundsTimeAndOutput(t *testing.T) {
+	ctx, cancel := context.WithTimeout(context.Background(), 200*time.Millisecond)
+	defer cancel()
+	if o := execRun(ctx, nil, "sleep", "5"); o.Err != ErrTimedOut {
+		t.Fatalf("%+v", o)
+	}
+	if o := execRun(context.Background(), nil, "no-such-program-here"); o.Err != ErrNotInstalled {
+		t.Fatalf("%+v", o)
+	}
+	o := execRun(context.Background(), nil, "head", "-c", strconv.Itoa(MostOutput+10), "/dev/zero")
+	if !o.Cut || len(o.Stdout) != MostOutput {
+		t.Fatalf("cut %v, %d bytes", o.Cut, len(o.Stdout))
+	}
+}

modules/polychromatic/cmd/polychromatic-tools/main.go

@@ -0,0 +1,51 @@
+// The polychromatic module's Go tools bundle (novox/hq ADR 0188, ADR 0193, ADR 0208): the Razer
+// peripherals' tray in the operator's session, served by the node's runtime as the operator account.
+// The module holds no seat, so every tool is its own. The driver and the daemon the tray drives are
+// the openrazer module's tools.
+package main
+
+import (
+	"fmt"
+	"os"
+
+	stdio "git.novox.be/novox/mesh-sdk/go"
+)
+
+func main() {
+	if err := stdio.Serve("", tools()); err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+}
+
+var machine = NewMachine()
+
+func tools() []stdio.Tool {
+	return []stdio.Tool{
+		{
+			Name: "polychromatic_status",
+			Description: "The Razer peripherals' tray: whether it runs (pid, since, and the unit or session " +
+				"scope it runs in), the installed version and whether it came from outside the official " +
+				"repositories, what starts it at login, the package's login helper and the application's own " +
+				"tray setting, and whether the openrazer daemon behind it answers, with how many devices. " +
+				"Never starts the tray or the daemon. (r)",
+			Run: func(map[string]any) (any, error) { return machine.Status() },
+		},
+		{
+			Name: "polychromatic_restart",
+			Description: "End the tray (asked first, then forced after 5 s) and start it again in the operator's " +
+				"desktop session, under the account's service manager. Answers the pids ended and the new one. " +
+				"Needs someone logged in to the desktop. (a)",
+			Run: func(map[string]any) (any, error) { return machine.Restart() },
+		},
+		{
+			Name: "polychromatic_check",
+			Description: "Check what the module promises and relies on: the package is installed (by hand: it is " +
+				"outside the official repositories); the tray has exactly one start (the module's line in the " +
+				"window manager's configuration; the package's login helper must not start it too); it runs " +
+				"once in a desktop session; and the openrazer daemon answers. Answers ok and each finding with " +
+				"what to do. (r)",
+			Run: func(map[string]any) (any, error) { return machine.Check() },
+		},
+	}
+}

modules/polychromatic/cmd/polychromatic-tools/manifest_test.go

@@ -0,0 +1,128 @@
+package main
+
+import (
+	"encoding/json"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"reflect"
+	"strings"
+	"testing"
+)
+
+// polychromatic's shape (novox/hq ADR 0205, ADR 0208, ADR 0212): no package (the tray is outside the
+// official repositories and kept as found), the X display on its own machine, one contribution to the
+// window manager's configuration that is the tray's one start, nothing of the openrazer module's, and
+// the Go bundle serving exactly the listed polychromatic_ tools.
+
+type manifest struct {
+	Module        string           `json:"module"`
+	Version       string           `json:"version"`
+	Capabilities  []string         `json:"capabilities"`
+	Requires      []string         `json:"requires"`
+	Tools         []string         `json:"tools"`
+	Resources     []map[string]any `json:"resources"`
+	Claims        []any            `json:"claims"`
+	Seats         []any            `json:"seats"`
+	Shell         []any            `json:"shell"`
+	Contributions []struct {
+		Seat    string `json:"seat"`
+		Kind    string `json:"kind"`
+		Content string `json:"content"`
+	} `json:"contributions"`
+	Environment any `json:"environment"`
+	Build       struct {
+		Artifacts []map[string]any `json:"artifacts"`
+	} `json:"build"`
+}
+
+func readManifest(t *testing.T) (manifest, string) {
+	t.Helper()
+	raw, err := os.ReadFile(filepath.Join("..", "..", "module.json"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	dec := json.NewDecoder(strings.NewReader(string(raw)))
+	dec.DisallowUnknownFields()
+	var m manifest
+	if err := dec.Decode(&m); err != nil {
+		t.Fatalf("module.json: %v", err)
+	}
+	return m, string(raw)
+}
+
+func TestTheToolsAgreeWithTheManifest(t *testing.T) {
+	m, raw := readManifest(t)
+	served := map[string]bool{}
+	for _, tool := range tools() {
+		served[tool.Name] = true
+		if !strings.HasPrefix(tool.Name, "polychromatic_") || strings.TrimSpace(tool.Description) == "" {
+			t.Errorf("%s: prefixed %s and described", tool.Name, "polychromatic_")
+		}
+	}
+	for _, name := range m.Tools {
+		if !served[name] {
+			t.Errorf("module.json lists %s, which the bundle does not serve", name)
+		}
+		delete(served, name)
+	}
+	for name := range served {
+		t.Errorf("the bundle serves %s, which module.json does not list", name)
+	}
+	if len(m.Build.Artifacts) != 1 {
+		t.Fatalf("%v", m.Build.Artifacts)
+	}
+	b := m.Build.Artifacts[0]
+	if b["kind"] != "bundle" || b["language"] != "go" || b["system"] != "arch" ||
+		b["from"] != "cmd/polychromatic-tools" || b["binary"] != "polychromatic-tools" {
+		t.Errorf("the Go tools bundle: %v", b)
+	}
+	s := strings.ToLower(raw)
+	for _, never := range []string{"/home/", "jochen", "g14", "shanks", "novox.be", "http", "password", "token"} {
+		if strings.Contains(s, never) {
+			t.Errorf("module.json names %q", never)
+		}
+	}
+}
+
+func TestItDeclaresNoPackageAndContributesTheTraysOneStart(t *testing.T) {
+	m, raw := readManifest(t)
+	if m.Module != "polychromatic" || !reflect.DeepEqual(m.Requires, []string{"x11-display"}) {
+		t.Fatalf("%+v", m)
+	}
+	if m.Resources != nil || m.Capabilities != nil || m.Claims != nil || m.Seats != nil || m.Environment != nil || m.Shell != nil {
+		t.Fatal("no package (outside the official repositories), no seat, no environment, no xinitrc start")
+	}
+	if len(m.Contributions) != 1 || m.Contributions[0].Seat != "node-display-session" || m.Contributions[0].Kind != "config" {
+		t.Fatalf("%+v", m.Contributions)
+	}
+	var code []string
+	for _, l := range strings.Split(m.Contributions[0].Content, "\n") {
+		if l = strings.TrimSpace(l); l != "" && !strings.HasPrefix(l, "#") {
+			code = append(code, l)
+		}
+	}
+	if !reflect.DeepEqual(code, []string{"exec --no-startup-id " + trayWord}) {
+		t.Fatalf("one line, the tray's start with exec (a reload must not start it again): %q", code)
+	}
+	for _, never := range []string{"openrazer", "preferences.json", "autostart\""} {
+		if strings.Contains(raw, never) {
+			t.Errorf("module.json names %s", never)
+		}
+	}
+}
+
+// The window manager's own check parses the line, as the i3 module's catalogue-wide test does with
+// every contribution together.
+func TestTheContributionParsesInI3(t *testing.T) {
+	i3, err := exec.LookPath("i3")
+	if err != nil {
+		t.Skip("no i3 here to check with")
+	}
+	m, _ := readManifest(t)
+	path := filepath.Join(t.TempDir(), "config")
+	os.WriteFile(path, []byte("set $mod Mod4\n"+m.Contributions[0].Content), 0o644)
+	if out, err := exec.Command(i3, "-C", "-c", path).CombinedOutput(); err != nil || strings.Contains(string(out), "ERROR") {
+		t.Fatalf("i3 -C: %v %s", err, out)
+	}
+}

modules/polychromatic/cmd/polychromatic-tools/polychromatic.go

@@ -0,0 +1,213 @@
+package main
+
+// Polychromatic's tray as the tools see it: its processes, its one start (the module's line in the
+// window manager's configuration), the package's login helper and the one setting of the application's
+// that makes the helper start the tray too, and whether the daemon it drives answers. The daemon is
+// the openrazer module's; it is asked with --auto-start=no, so a question never starts it.
+
+import (
+	"encoding/json"
+	"fmt"
+	"strings"
+	"time"
+)
+
+const (
+	trayComm    = "polychromatic-t" // the kernel keeps 15 characters of polychromatic-tray-applet
+	trayWord    = "polychromatic-tray-applet"
+	trayBin     = "/usr/bin/polychromatic-tray-applet"
+	helperEntry = "polychromatic-autostart.desktop"
+	restartAs   = "mesh-polychromatic-tray"
+	packageFor  = "polychromatic"
+	prefsFile   = ".config/polychromatic/preferences.json"
+	settingName = "Preferences → Tray → \"Start the tray applet when I log on\""
+)
+
+// trays are the tray's processes. Its cut command name is this bundle's own too, so the program is
+// matched by its full name.
+func (m *Machine) trays() []Proc { return m.procsOf(trayComm, trayWord) }
+
+// TraySetting is the application's own setting that makes its login helper start the tray. The
+// module never writes it: the application rewrites its preferences file itself.
+type TraySetting struct {
+	// Autostart is the setting; Polychromatic's default is on.
+	Autostart bool   `json:"autostart"`
+	Delay     int    `json:"autostart_delay_seconds"`
+	From      string `json:"from"`
+}
+
+// setting reads the tray keys of the preferences file and nothing else of it.
+func (m *Machine) setting() TraySetting {
+	s := TraySetting{Autostart: true, From: "Polychromatic's default (no preferences file)"}
+	raw, err := readBounded(m.home(prefsFile))
+	if err != nil {
+		return s
+	}
+	var doc struct {
+		Tray struct {
+			Autostart *bool `json:"autostart"`
+			Delay     int   `json:"autostart_delay"`
+		} `json:"tray"`
+	}
+	if err := json.Unmarshal(raw, &doc); err != nil {
+		s.From = "Polychromatic's default (the preferences file does not parse)"
+		return s
+	}
+	s.From = "~/" + prefsFile
+	if doc.Tray.Autostart != nil {
+		s.Autostart = *doc.Tray.Autostart
+	}
+	s.Delay = doc.Tray.Delay
+	return s
+}
+
+// Backend is whether the openrazer daemon answers, and how many devices it has.
+type Backend struct {
+	Answers    bool   `json:"answers"`
+	Devices    int    `json:"devices"`
+	Unanswered string `json:"unanswered,omitempty"`
+}
+
+func (m *Machine) backend() Backend {
+	args := []string{"--user", "--auto-start=no", "--json=short", "call", "org.razer", "/org/razer", "razer.devices", "getDevices"}
+	o := m.cmd(5*time.Second, m.bus(), "busctl", args...)
+	if err := failed(o, "busctl", args...); err != nil {
+		return Backend{Unanswered: "the openrazer daemon does not answer (asked without starting it): " + err.Error()}
+	}
+	var doc struct {
+		Data [][]string `json:"data"`
+	}
+	if err := json.Unmarshal([]byte(o.Stdout), &doc); err != nil || len(doc.Data) != 1 {
+		return Backend{Unanswered: "the daemon's device list is not busctl's JSON"}
+	}
+	return Backend{Answers: true, Devices: len(doc.Data[0])}
+}
+
+// foreign says whether the package came from outside the official repositories (pacman -Qm).
+func (m *Machine) foreign() bool {
+	o := m.cmd(0, nil, "pacman", "-Qqm", packageFor)
+	return o.Err == nil && o.Code == 0 && strings.TrimSpace(o.Stdout) == packageFor
+}
+
+// StatusAnswer is what polychromatic_status answers.
+type StatusAnswer struct {
+	Installed string      `json:"installed,omitempty"`
+	Foreign   bool        `json:"outside_official_repositories"`
+	Tray      []Proc      `json:"tray"`
+	StartedBy []string    `json:"started_by"`
+	Helper    Autostart   `json:"login_helper"`
+	Setting   TraySetting `json:"tray_setting"`
+	Backend   Backend     `json:"backend"`
+}
+
+// Status reads the tray, what starts it, and whether the daemon behind it answers.
+func (m *Machine) Status() (StatusAnswer, error) {
+	s := StatusAnswer{Tray: m.trays(), StartedBy: []string{}, Helper: m.autostart(helperEntry),
+		Setting: m.setting(), Backend: m.backend()}
+	if s.Tray == nil {
+		s.Tray = []Proc{}
+	}
+	v, err := m.installed(packageFor)
+	if err != nil {
+		return s, err
+	}
+	s.Installed = v
+	if v != "" {
+		s.Foreign = m.foreign()
+	}
+	for _, l := range m.i3Starts(trayWord) {
+		s.StartedBy = append(s.StartedBy, "window manager: "+l)
+	}
+	if s.Helper.Starts && s.Setting.Autostart {
+		s.StartedBy = append(s.StartedBy, "the login helper ("+s.Helper.From+"), as the tray setting is on")
+	}
+	return s, nil
+}
+
+// RestartAnswer is what polychromatic_restart answers.
+type RestartAnswer struct {
+	Ended   []int   `json:"ended"`
+	Killed  []int   `json:"killed,omitempty"`
+	Running []Proc  `json:"running"`
+	Session Session `json:"session"`
+	Unit    string  `json:"unit"`
+}
+
+// Restart ends the tray and starts it again in the operator's session, under the account's service
+// manager.
+func (m *Machine) Restart() (RestartAnswer, error) {
+	s, err := m.session()
+	if err != nil {
+		return RestartAnswer{}, err
+	}
+	a := RestartAnswer{Session: s, Unit: restartAs + ".service"}
+	a.Ended, a.Killed = m.stopProcs(5*time.Second, m.trays())
+	if err := m.detach(s, restartAs, trayBin); err != nil {
+		return a, err
+	}
+	a.Running = m.waitForOf(trayComm, trayWord, 4*time.Second)
+	if len(a.Running) == 0 {
+		return a, fmt.Errorf("the tray was started as %s but no %s process appeared within 4 s: "+
+			"see `journalctl --user -u %s`", a.Unit, trayWord, a.Unit)
+	}
+	return a, nil
+}
+
+// CheckAnswer is what polychromatic_check answers.
+type CheckAnswer struct {
+	OK       bool      `json:"ok"`
+	Findings []Finding `json:"findings"`
+	Starts   []string  `json:"starts"`
+}
+
+// Check verifies what the module promises and relies on: the package (found, not installed by the
+// mesh); one start, the module's window-manager line; the tray running once; and the daemon answering.
+func (m *Machine) Check() (CheckAnswer, error) {
+	a := CheckAnswer{Findings: []Finding{}, Starts: []string{}}
+	add := func(what, do string) { a.Findings = append(a.Findings, Finding{what, do}) }
+	v, err := m.installed(packageFor)
+	if err != nil {
+		return a, err
+	}
+	if v == "" {
+		add("polychromatic is not installed. It is outside the official repositories, so the mesh does not install it",
+			"install it from the AUR by hand; it brings the openrazer packages with it")
+	}
+
+	lines := m.i3Starts(trayWord)
+	for _, l := range lines {
+		a.Starts = append(a.Starts, "window manager: "+l)
+	}
+	switch {
+	case len(lines) == 0:
+		add("the window manager does not start the tray", "push the module: its line in the window manager's configuration is the tray's start")
+	case len(lines) > 1:
+		for _, l := range lines[1:] {
+			add("a second start: "+l, "remove the line; the module's line is the tray's one start")
+		}
+	}
+	helper := m.autostart(helperEntry)
+	if set := m.setting(); helper.Starts && set.Autostart {
+		a.Starts = append(a.Starts, "login helper: "+helper.From+" (the tray setting is on)")
+		add("a second start: the package's login helper starts the tray too, as the tray setting is on ("+set.From+")",
+			"in Polychromatic, untick "+settingName+". The helper keeps its other work: it resumes the devices' effects")
+	}
+	if own := m.autostart(trayWord + ".desktop"); own.Starts {
+		a.Starts = append(a.Starts, "XDG autostart: "+own.From)
+		add("a second start: "+own.From, "remove it; the module's line is the tray's one start")
+	}
+
+	if _, err := m.session(); err == nil {
+		switch running := m.trays(); {
+		case len(running) == 0:
+			add("no tray runs in the desktop session", "polychromatic_restart")
+		case len(running) > 1:
+			add(fmt.Sprintf("%d trays run", len(running)), "polychromatic_restart ends them all and starts one")
+		}
+	}
+	if b := m.backend(); !b.Answers {
+		add(b.Unanswered+": the tray has no devices to show", "assign the openrazer module; openrazer_check says why the daemon is not running")
+	}
+	a.OK = len(a.Findings) == 0
+	return a, nil
+}

modules/polychromatic/cmd/polychromatic-tools/polychromatic_test.go

@@ -0,0 +1,122 @@
+package main
+
+import (
+	"strings"
+	"testing"
+)
+
+// newTray is a machine with the tray as the module wants it: the module's line in i3's configuration,
+// the package's helper entry with the tray setting off, one tray running, and the daemon answering.
+func newTray(t *testing.T, running bool) *fake {
+	f := newFake(t)
+	f.write("/etc/xdg/autostart/"+helperEntry, "[Desktop Entry]\nExec=polychromatic-helper --autostart\n")
+	f.write(testHome+"/.config/i3/config", "exec --no-startup-id dex --autostart --environment i3\n# polychromatic\n"+
+		"exec --no-startup-id polychromatic-tray-applet\n")
+	f.write(testHome+"/"+prefsFile, `{"config_version":8,"tray":{"autostart":false,"autostart_delay":0,"mode":0},"editor":{}}`)
+	if running {
+		f.proc(4122, 1000, trayComm, []string{"polychromatic-tray-applet"}, "session-c1.scope")
+		// the tools themselves: the same cut command name
+		f.proc(4200, 1000, trayComm, []string{"/usr/lib/mesh/polychromatic-tools"}, "system.slice/mesh-runtime.service")
+	}
+	f.answer = func(name string, args []string) Output {
+		switch {
+		case name == "pacman" && args[0] == "-Q":
+			return Output{Stdout: "polychromatic 0.9.8-1\n"}
+		case name == "pacman" && args[0] == "-Qqm":
+			return Output{Stdout: "polychromatic\n"}
+		case name == "busctl":
+			return Output{Stdout: `{"type":"as","data":[["PM2148H00000001"]]}`}
+		}
+		return Output{}
+	}
+	return f
+}
+
+func TestStatusSaysWhatStartsTheTrayAndAsksTheDaemonWithoutStartingIt(t *testing.T) {
+	f := newTray(t, true)
+	s, err := f.Status()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if s.Installed != "0.9.8-1" || !s.Foreign || len(s.Tray) != 1 || !s.Backend.Answers || s.Backend.Devices != 1 ||
+		len(s.StartedBy) != 1 || !strings.HasPrefix(s.StartedBy[0], "window manager: ~/.config/i3/config:3") || s.Setting.Autostart {
+		t.Fatalf("%+v", s)
+	}
+	for _, c := range f.calls {
+		if strings.HasPrefix(c, "busctl") && !strings.Contains(c, "--auto-start=no") {
+			t.Fatalf("a bus call that could start the daemon: %s", c)
+		}
+	}
+}
+
+func TestTheTraySettingIsReadAndDefaultsOn(t *testing.T) {
+	f := newTray(t, false)
+	if s := f.setting(); s.Autostart || s.From != "~/"+prefsFile {
+		t.Fatalf("%+v", s)
+	}
+	f.write(testHome+"/"+prefsFile, `{"tray":{"autostart_delay":3}}`)
+	if s := f.setting(); !s.Autostart || s.Delay != 3 {
+		t.Fatalf("%+v", s)
+	}
+	f.write(testHome+"/"+prefsFile, `not json`)
+	if s := f.setting(); !s.Autostart || !strings.Contains(s.From, "does not parse") {
+		t.Fatalf("%+v", s)
+	}
+}
+
+func TestCheckPassesTheModulesOneStartAndNamesTheHelpersAsASecond(t *testing.T) {
+	f := newTray(t, true)
+	f.desktopSession()
+	c, err := f.Check()
+	if err != nil || !c.OK || len(c.Starts) != 1 {
+		t.Fatalf("%+v %v", c, err)
+	}
+
+	f.write(testHome+"/"+prefsFile, `{"tray":{"autostart":true}}`)
+	f.write(testHome+"/.config/i3/config.d/90-x.conf", "exec_always --no-startup-id polychromatic-tray-applet\n")
+	f.proc(4123, 1000, trayComm, []string{"polychromatic-tray-applet"}, "session-c1.scope")
+	f.answer = func(name string, args []string) Output {
+		switch name {
+		case "pacman":
+			return Output{Code: 1}
+		case "busctl":
+			return Output{Code: 1, Stderr: "Call failed: Unit openrazer-daemon.service failed"}
+		}
+		return Output{}
+	}
+	c, _ = f.Check()
+	var all []string
+	for _, x := range c.Findings {
+		all = append(all, x.What+" => "+x.Do)
+	}
+	got := strings.Join(all, "\n")
+	for _, want := range []string{"not installed", "a second start: ~/.config/i3/config.d/90-x.conf:1", "the package's login helper starts the tray too",
+		"Start the tray applet when I log on", "2 trays run", "openrazer daemon does not answer"} {
+		if !strings.Contains(got, want) {
+			t.Errorf("no finding %q in\n%s", want, got)
+		}
+	}
+
+	none := newTray(t, false)
+	none.write(testHome+"/.config/i3/config", "exec --no-startup-id dex --autostart --environment i3\n")
+	c, _ = none.Check()
+	if c.OK || !strings.Contains(c.Findings[0].What, "does not start the tray") {
+		t.Fatalf("%+v", c)
+	}
+}
+
+func TestRestartEndsTheTrayAndStartsItUnderTheServiceManager(t *testing.T) {
+	f := newTray(t, true)
+	if _, err := f.Restart(); err == nil || !strings.Contains(err.Error(), "no graphical session") {
+		t.Fatalf("without a desktop: %v", err)
+	}
+	f.desktopSession()
+	f.onStart = func(argv []string) { f.proc(9100, 1000, trayComm, argv, "app.slice/"+restartAs+".service") }
+	a, err := f.Restart()
+	if err != nil || len(a.Ended) != 1 || len(a.Running) != 1 || a.Running[0].PID != 9100 {
+		t.Fatalf("%+v %v", a, err)
+	}
+	if !f.called("systemd-run --user --collect --quiet --unit=" + restartAs + " --setenv=DISPLAY=:1") {
+		t.Fatalf("%q", f.calls)
+	}
+}

modules/polychromatic/go.mod

@@ -0,0 +1,5 @@
+module polychromatic
+
+go 1.22
+
+require git.novox.be/novox/mesh-sdk/go v0.1.7

modules/polychromatic/go.sum

@@ -0,0 +1,2 @@
+git.novox.be/novox/mesh-sdk/go v0.1.7 h1:C0sTQmtTiyYH7bnqZb7PusXnqA37gKuT7Nqjn9gG47w=
+git.novox.be/novox/mesh-sdk/go v0.1.7/go.mod h1:GFuZUElBZ9A++mxgIKo97aXXo+kV0uJ/UkbhQPPIbrY=

modules/polychromatic/module.json

@@ -0,0 +1,34 @@
+{
+  "module": "polychromatic",
+  "version": "1",
+  "requires": [
+    "x11-display"
+  ],
+  "tools": [
+    "polychromatic_status",
+    "polychromatic_restart",
+    "polychromatic_check"
+  ],
+  "contributions": [
+    {
+      "seat": "node-display-session",
+      "kind": "config",
+      "content": "# The Razer peripherals' tray (module polychromatic, novox/hq ADR 0208, ADR 0212). Owned by the mesh:\n# replaced at every push. This line is the tray's one start, at the session's start (exec, not\n# exec_always, so a reload starts nothing). The package's own login helper starts it too while the\n# application's setting \"Start the tray applet when I log on\" is ticked; polychromatic_check names\n# that as a second start.\nexec --no-startup-id polychromatic-tray-applet\n"
+    }
+  ],
+  "build": {
+    "artifacts": [
+      {
+        "name": "tools",
+        "kind": "bundle",
+        "language": "go",
+        "system": "arch",
+        "from": "cmd/polychromatic-tools",
+        "binary": "polychromatic-tools",
+        "loads": [
+          "polychromatic-tools"
+        ]
+      }
+    ]
+  }
+}

modules/slack/cmd/slack-tools/copies_test.go

@@ -0,0 +1,37 @@
+package main
+
+// The desktop applications whose bundles carry desktop.go. Each builds alone, so each has its own copy;
+// this test, itself one of the copied files, holds them to one text wherever the siblings are present.
+
+import (
+	"bytes"
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+var carriers = []string{"blueman", "forticlient", "nextcloud-client", "nm-applet", "openrazer", "polychromatic", "slack"}
+
+func TestEveryDesktopApplicationCarriesTheSameCopy(t *testing.T) {
+	compared := 0
+	for _, module := range carriers {
+		dir := filepath.Join("..", "..", "..", module, "cmd", module+"-tools")
+		if _, err := os.Stat(dir); err != nil {
+			continue
+		}
+		for _, f := range []string{"desktop.go", "desktop_test.go", "copies_test.go"} {
+			mine, err := os.ReadFile(f)
+			if err != nil {
+				t.Fatal(err)
+			}
+			theirs, err := os.ReadFile(filepath.Join(dir, f))
+			if err != nil || !bytes.Equal(mine, theirs) {
+				t.Errorf("%s's copy of %s differs from this one: change every copy together", module, f)
+			}
+		}
+		compared++
+	}
+	if compared == 0 {
+		t.Log("no sibling copies beside this module")
+	}
+}

modules/slack/cmd/slack-tools/desktop.go

@@ -1,8 +1,8 @@
 package main
 
-// desktop.go is the same file in the nextcloud-client, blueman and slack bundles: a
-// tray application of the operator's graphical session, seen from the node's tool runtime (novox/hq
-// ADR 0208).
+// desktop.go is the same file in every desktop application's bundle (copies_test.go names them and
+// holds them to one text): a tray application of the operator's graphical session, seen from the
+// node's tool runtime (novox/hq ADR 0208).
 //
 // The runtime is a system service running as the operator account (ADR 0175): it has the account's
 // uid and none of the session's environment. A tool that starts something on the desktop finds the
@@ -252,6 +252,22 @@ func (m *Machine) procs(comm string) []Proc {
 	return out
 }
 
+// procsOf are the account's processes named comm whose program is word. The kernel keeps 15
+// characters of a command name, so a longer name can share them with another program's: this bundle's
+// own binary among them (polychromatic-tools and polychromatic-tray-applet are both polychromatic-t).
+// The program is the first word of the command line, or the second for a script run by its
+// interpreter. An empty word keeps every process named comm.
+func (m *Machine) procsOf(comm, word string) []Proc {
+	var out []Proc
+	for _, p := range m.procs(comm) {
+		f := strings.Fields(p.Command)
+		if word == "" || (len(f) > 0 && filepath.Base(f[0]) == word) || (len(f) > 1 && filepath.Base(f[1]) == word) {
+			out = append(out, p)
+		}
+	}
+	return out
+}
+
 // uidOf is the real uid on a process's status, -1 when unreadable.
 func (m *Machine) uidOf(dir string) int {
 	for _, l := range strings.Split(readTrimmed(filepath.Join(dir, "status")), "\n") {
@@ -412,12 +428,19 @@ func (m *Machine) detach(s Session, unit string, argv ...string) error {
 // stop ends every process of the account named in comms: SIGTERM, then SIGKILL for what is still
 // there after grace. It answers the pids that ended and those that had to be killed.
 func (m *Machine) stop(grace time.Duration, comms ...string) (ended, killed []int) {
-	var pids []int
+	var ps []Proc
 	for _, c := range comms {
-		for _, p := range m.procs(c) {
-			if m.Kill(p.PID, syscall.SIGTERM) == nil {
-				pids = append(pids, p.PID)
-			}
+		ps = append(ps, m.procs(c)...)
+	}
+	return m.stopProcs(grace, ps)
+}
+
+// stopProcs ends the processes given, as stop does.
+func (m *Machine) stopProcs(grace time.Duration, ps []Proc) (ended, killed []int) {
+	var pids []int
+	for _, p := range ps {
+		if m.Kill(p.PID, syscall.SIGTERM) == nil {
+			pids = append(pids, p.PID)
 		}
 	}
 	alive := func() []int {
@@ -452,10 +475,13 @@ func (m *Machine) stop(grace time.Duration, comms ...string) (ended, killed []in
 }
 
 // waitFor waits up to d for a process of the account named comm, and answers what it found.
-func (m *Machine) waitFor(comm string, d time.Duration) []Proc {
+func (m *Machine) waitFor(comm string, d time.Duration) []Proc { return m.waitForOf(comm, "", d) }
+
+// waitForOf waits up to d for a process of the account named comm whose program is word (procsOf).
+func (m *Machine) waitForOf(comm, word string, d time.Duration) []Proc {
 	step := 250 * time.Millisecond
 	for waited := time.Duration(0); ; waited += step {
-		if p := m.procs(comm); len(p) > 0 || waited >= d {
+		if p := m.procsOf(comm, word); len(p) > 0 || waited >= d {
 			return p
 		}
 		m.Sleep(step)

modules/slack/cmd/slack-tools/desktop_test.go

@@ -1,7 +1,7 @@
 package main
 
-// The fake machine the tests run against, and the tests of desktop.go. The same in the
-// nextcloud-client, blueman and slack bundles.
+// The fake machine the tests run against, and the tests of desktop.go. The same in every desktop
+// application's bundle (copies_test.go).
 
 import (
 	"context"
@@ -113,6 +113,23 @@ func TestProcessesAreTheAccountsOwnWithWhereAndWhenTheyStarted(t *testing.T) {
 	}
 }
 
+func TestAProgramIsToldFromAnotherSharingItsCutName(t *testing.T) {
+	f := newFake(t)
+	f.proc(10, 1000, "polychromatic-t", []string{"/usr/bin/python", "/usr/bin/polychromatic-tray-applet"}, "s.scope")
+	f.proc(11, 1000, "polychromatic-t", []string{"polychromatic-tray-applet"}, "s.scope")
+	f.proc(12, 1000, "polychromatic-t", []string{"/usr/lib/mesh/polychromatic-tools"}, "s.scope")
+	if got := f.procsOf("polychromatic-t", "polychromatic-tray-applet"); len(got) != 2 || got[0].PID != 10 || got[1].PID != 11 {
+		t.Fatalf("%+v", got)
+	}
+	if got := f.procsOf("polychromatic-t", ""); len(got) != 3 {
+		t.Fatalf("%+v", got)
+	}
+	ended, _ := f.stopProcs(time.Second, f.procsOf("polychromatic-t", "polychromatic-tray-applet"))
+	if len(ended) != 2 || len(f.procs("polychromatic-t")) != 1 {
+		t.Fatalf("ended %v; the tools' own process must stay", ended)
+	}
+}
+
 func TestTheSessionIsTheWindowManagersAndNoneIsSaidPlainly(t *testing.T) {
 	f := newFake(t)
 	if _, err := f.session(); err == nil || !strings.Contains(err.Error(), "no graphical session") {

modules/xdg/README.md

@@ -106,9 +106,15 @@ The person's list keeps every line as found, the dropped ones included. `xdg_che
 ## Autostart: listed, not owned
 
 An XDG autostart entry belongs to the module of the application it starts, as `picom` does: picom's
-package entry is its one starter. A future `nextcloud-client` module owns `Nextcloud.desktop` (the
-client writes it itself), a blueman module beside `bluetooth` owns blueman's, and Slack's and JetBrains
-Toolbox's entries would be their modules'.
+package entry is its one starter. `nextcloud-client` holds `Nextcloud.desktop` as its start (the client
+writes it itself), and `blueman`, `nm-applet` and `forticlient` hold their packages' entries as theirs.
+`polychromatic`'s helper entry is that module's too, though the tray's start is its window-manager line.
+Slack's and JetBrains Toolbox's entries would be their modules'. Two entries on the desktop have no
+module and are left as found: the print applet's (the `cups` README says why) and geoclue's demo
+agent (`/usr/lib/geoclue-2.0/demos/agent`). geoclue is there as a dependency of an application of the
+operator's, not as a choice; the agent is what answers geoclue's question "may this program know
+where the machine is" outside GNOME, whose own shell answers it there. It is a dependency's piece, so
+it belongs to whoever installs geoclue on purpose, and nobody does yet.
 This module only says what is there, and what the session does with it.
 
 The session's starter is `i3`'s `dex --autostart --environment i3`. `xdg_autostart` decides each