The node seat node-engine: held by every node's engine, its six verbs and three events, and no module may claim it (issue 774, ADR 0563 §1)

go/catalogue/engine_seat.go

@@ -0,0 +1,57 @@
+package catalogue
+
+// The node seat node-engine (novox/hq ADR 0563 §1): held on every node by that node's engine (mesh-host), which serves
+// its verbs on its own bus account. No module claims it and no assignment holds it: what the mesh knows of its holder
+// is the node's record and the engine's haves (ADR 0563 §1 changes ADR 0110 §6 and §7 for this one seat).
+//
+// Its verbs carry no signature (§7): the runtime proves the caller, which matters only for the record. The read-only
+// ones change nothing or are bounded in the engine's own state (§2); hand-over and access-act perform nothing on the
+// call, and act only on the operator's warrant to the engine's own ask (§3).
+
+// EngineSeat is the node seat every node's engine holds.
+const EngineSeat = "node-engine"
+
+// EngineVerbs are the node-engine seat's verbs, in the order ADR 0563 §1 names them.
+func EngineVerbs() []Verb {
+	return []Verb{
+		{Name: "hand-over", Description: "Hand a directory this machine uses as found to the mesh (novox/hq ADR 0563 §3, " +
+			"§5): the engine judges the path as it does every hand-over (absolute, as it states it, used as found, " +
+			"reached through no link) and refuses in words, or asks the operator on their channel at the level approve, " +
+			"binding the owner, group and mode it will set. Nothing changes on the call: only the operator's yes hands " +
+			"it over. One ask is open per path; acts shows where it stands.",
+			Input: schema(map[string]string{"path": "the directory's absolute path, as the engine states it",
+				"why": "why it is asked, in words the operator reads"}, []string{"path"})},
+		{Name: "access-act", Description: "Ask the operator for the take act on a library whose root holds data outside its " +
+			"group (novox/hq ADR 0328 §7, ADR 0563 §3, §4), on the library's home engine: the access as declared and its " +
+			"root as last declared, judged and refused in words or asked at the level approve. Only the operator's yes " +
+			"sets the library's group, group write and setgid under its root. One ask is open per access.",
+			Input: schema(map[string]string{"act": "the act: take", "access": "the access, library:<name>",
+				"why": "why it is asked, in words the operator reads"}, []string{"act", "access"})},
+		{Name: "judge-directories", Description: "Which of this machine's declared directories the engine would refuse to " +
+			"make or keep, one line each (novox/hq ADR 0563 §2). Read-only: changes no owner or mode.",
+			Input: schema(map[string]string{}, nil)},
+		{Name: "setuid-search", Description: "Throw away the engine's last search for setuid programs and start a full one " +
+			"(novox/hq ADR 0563 §2); until it completes root-free answers that the machine is not judged yet. Refused while " +
+			"one runs, and when one was started within the hour, naming when the next may start.",
+			Input: schema(map[string]string{"why": "why it is asked, in words"}, nil)},
+		{Name: "root-free", Description: "Whether this machine is root-free (novox/hq ADR 0259 §8, ADR 0563 §6): free only " +
+			"on the engine's own verdict, at most fifteen minutes old, that the account agents run as cannot become root " +
+			"without a person, and the login shell's execute not served here. Anything else is no pass, and says why. " +
+			"Answered by this machine's engine alone.",
+			Input: schema(map[string]string{}, nil)},
+		{Name: "acts", Description: "Every act this machine's engine was asked through this seat (novox/hq ADR 0563 §9): " +
+			"each hand-over, access act and setuid search, open, done or refused, with who asked, the ask and the " +
+			"operator's warrant. Read-only.",
+			Input: schema(map[string]string{"limit": "at most this many, newest"}, nil)},
+	}
+}
+
+// EngineEvents are what the seat says of an act, each naming the act, the path or access, the caller as the runtime
+// proved it and the ask (ADR 0563 §1).
+var EngineEvents = []string{"asked", "done", "refused"}
+
+// engineSeat is the seat's row in the closed set.
+func engineSeat() Seat {
+	return Seat{Name: EngineSeat, Scope: ScopeNode, Serves: EngineVerbs(), Emits: append([]string(nil), EngineEvents...),
+		HeldByTheEngine: true, Decision: "novox/hq ADR 0563"}
+}

go/catalogue/seats.go

@@ -67,6 +67,10 @@ type Seat struct {
 	// names paths. Compiled, never stored, like Receives: adding or taking away a path is a decision,
 	// recorded, and the store's rows carry no column for it.
 	Paths []SeatPath
+	// HeldByTheEngine says the seat is held on every node by that node's engine, which serves its verbs on its own bus
+	// account (novox/hq ADR 0563 §1): no module claims it and no assignment holds it. Compiled, never stored, like
+	// Receives.
+	HeldByTheEngine bool
 	// Decision is the record that made it a seat.
 	Decision string
 }
@@ -456,6 +460,8 @@ var defaultSeats = append([]Seat{
 	// A node's files, read and managed (novox/hq ADR 0394, files.go): beside node-reads until mesh-files is assigned
 	// on every node, then node-reads goes (ADR 0394 §9).
 	{Name: FilesSeat, Scope: ScopeNode, Decision: "novox/hq ADR 0394", Serves: filesVerbs()},
+	// The node's engine's own verbs and asks (novox/hq ADR 0563 §1): held by the engine on every node, by no module.
+	engineSeat(),
 },
 	// The graphical session's roles (novox/hq ADR 0208), last because they are a workstation's.
 	graphicalSessionSeats()...)
@@ -529,7 +535,8 @@ func UseSeats(s []Seat) {
 			row.Paths = d.Paths
 			row.Replicated = d.Replicated
 			row.PulledByKind = d.PulledByKind
-			row.Yields = d.Yields // never stored (ADR 0553)
+			row.Yields = d.Yields                   // never stored (ADR 0553)
+			row.HeldByTheEngine = d.HeldByTheEngine // never stored (ADR 0563)
 			row.Serves = optionalAsCompiled(row.Serves, d.Serves)
 		}
 		merged = append(merged, row)
@@ -642,6 +649,13 @@ func claimProblems(m Manifest) []string {
 	}
 
 	for _, c := range m.Claims {
+		if s, known := SeatNamed(c.Name); known && s.HeldByTheEngine {
+			// The node's engine holds it on every node, and no module may (novox/hq ADR 0563 §1): a module answering
+			// root-free or a hand-over would be an agent answering it.
+			problems = append(problems, fmt.Sprintf("%s claims %s, which every node's engine holds itself and no "+
+				"module may (novox/hq ADR 0563 §1)", m.Module, c.Name))
+			continue
+		}
 		if _, known := SeatNamed(c.Name); known {
 			// **A seat's scope and what it delivers are not judged here** (novox/hq ADR 0122).
 			// This function runs wherever a manifest is parsed, and one of those places is the

go/catalogue/seats_test.go

@@ -64,6 +64,24 @@ func TestTheSeatsAreAClosedSetAndEachNamesItsDecision(t *testing.T) {
 	if strings.Join(checkerVerbs, ",") != "try,try-read,try-end" {
 		t.Errorf("the checker seat serves %v", checkerVerbs)
 	}
+	// The node seat node-engine is the node's engine's (novox/hq ADR 0563 §1): at node scope, delivering nothing, its six
+	// verbs and three events, held by no assignment, and a module's claim of it refused.
+	if engine, ok := SeatNamed(EngineSeat); !ok || engine.Scope != ScopeNode || engine.Delivers != "" || !engine.HeldByTheEngine {
+		t.Errorf("node-engine is %+v, not a node seat delivering nothing that the engine holds", engine)
+	} else {
+		var verbs []string
+		for _, v := range engine.Serves {
+			verbs = append(verbs, v.Name)
+		}
+		if strings.Join(verbs, ",") != "hand-over,access-act,judge-directories,setuid-search,root-free,acts" ||
+			strings.Join(engine.Emits, ",") != "asked,done,refused" {
+			t.Errorf("node-engine serves %v and emits %v", verbs, engine.Emits)
+		}
+	}
+	if _, err := ParseManifest([]byte(`{"module":"thing","version":"1","claims":[{"name":"node-engine","scope":"node"}]}`)); err == nil ||
+		!strings.Contains(err.Error(), "node-engine") {
+		t.Errorf("a module's claim of node-engine was not refused: %v", err)
+	}
 	// Forty-six with the three build seats replacing node-build-agent and the retired mesh-build-machine (novox/hq
 	// ADR 0525 §2, §10); forty-five with node-files (novox/hq ADR 0394); forty-four again once node-reads goes.
 	// Forty-four with node-provisioner (novox/hq ADR 0349 clause 3); forty-three with mesh-provisioner (novox/hq ADR 0349 clause 3); forty-two with mesh-config (novox/hq ADR 0348 §9); forty-one with node-reads (novox/hq ADR 0310); forty with node-nfs-server and node-mounts (novox/hq ADR 0263); thirty-eight with node-resolver (novox/hq ADR 0247); thirty-seven with mesh-delivery (novox/hq ADR 0239); thirty-six since node-resolver-config retired
@@ -77,9 +95,9 @@ func TestTheSeatsAreAClosedSetAndEachNamesItsDecision(t *testing.T) {
 	// node-container-runtime (ADR 0207); nineteen with node-environment and node-login-shell (ADR 0203,
 	// ADR 0204); seventeen with node-build-agent (ADR 0190). One fewer once the retired
 	// mesh-build-machine row goes, when no registered manifest claims it.
-	// Forty-eight with mesh-delivery-checker (novox/hq ADR 0547 §10, issue 774).
-	if len(Seats()) != 48 {
-		t.Errorf("the mesh defines %d seats rather than 48; the set is closed, so a change here is "+
+	// Forty-eight with mesh-delivery-checker (novox/hq ADR 0547 §10, issue 774); forty-nine with node-engine (novox/hq ADR 0563 §1).
+	if len(Seats()) != 49 {
+		t.Errorf("the mesh defines %d seats rather than 49; the set is closed, so a change here is "+
 			"a decision (novox/hq ADR 0110): %s", len(Seats()), seatNames())
 	}
 }