internal/bootstrap/inuse.go

@@ -12,14 +12,18 @@ import (
 )
 
 // quiet are the processes every fresh machine runs that serve nobody: name resolution (whose
-// link-local resolver listens on TCP as well as UDP, on every address), address configuration and
+// link-local resolver listens on TCP as well as UDP, on every address) and the network manager's
-// time. ss names a process by its first fifteen characters, so both spellings are here. Measured
+// address configuration. ss names a process by its first fifteen characters, so both spellings are
-// on a freshly installed lab machine (testdata/fresh-machine-listeners.txt): these and nothing else.
+// here.
+//
+// **Only what the measurement found** (novox/hq ADR 0101): these two hold every listener on a
+// freshly installed lab machine (testdata/fresh-machine-listeners.txt) and nothing else does. A
+// daemon joins this list with a measurement of a fresh machine that holds it, never by guess — a
+// time client or an address-configuration client listening on a machine that does not run one as
+// standard is something somebody installed, and that is a machine in use.
 var quiet = map[string]bool{
 	"systemd-resolved": true, "systemd-resolve": true,
 	"systemd-networkd": true, "systemd-network": true,
-	"systemd-timesyncd": true, "systemd-timesyn": true,
-	"dhcpcd": true,
 }
 
 // InUse says what makes this machine a machine in use (novox/hq ADR 0100): every running container

internal/bootstrap/inuse_test.go

@@ -14,16 +14,14 @@ import (
 // and listener it counted.
 
 // Lines as `ss -Hltunp` prints them. The ssh, samba, loopback and proxy lines are captured from a
-// real machine; the resolver, DHCP and time lines are written in the same shape. What a fresh machine
+// real machine; the resolver and network-manager lines are written in the same shape. What a fresh
-// actually runs is measured in testdata/fresh-machine-listeners.txt.
+// machine actually runs is measured in testdata/fresh-machine-listeners.txt.
 const inUseSockets = `tcp LISTEN 0      128                                        0.0.0.0:22    0.0.0.0:* users:(("sshd",pid=1188536,fd=6))
 tcp LISTEN 0      128                                           [::]:22       [::]:* users:(("sshd",pid=1188536,fd=7))
 tcp LISTEN 0      32                                       127.0.0.1:53    0.0.0.0:* users:(("dnsmasq",pid=1189392,fd=7))
 tcp LISTEN 0      4096                                     127.0.0.1:5432  0.0.0.0:* users:(("docker-proxy",pid=1854543,fd=7))
 udp UNCONN 0      0                                          0.0.0.0:5355  0.0.0.0:* users:(("systemd-resolve",pid=301,fd=11))
 udp UNCONN 0      0                                    192.0.2.10%eth0:68  0.0.0.0:* users:(("systemd-network",pid=280,fd=19))
-udp UNCONN 0      0                                          0.0.0.0:68    0.0.0.0:* users:(("dhcpcd",pid=270,fd=9))
-udp UNCONN 0      0                                          0.0.0.0:123   0.0.0.0:* users:(("systemd-timesyn",pid=260,fd=9))
 `
 
 const servingSockets = `tcp LISTEN 0      50                                         0.0.0.0:445   0.0.0.0:* users:(("smbd",pid=1248,fd=29))
@@ -47,7 +45,7 @@ func TestAFreshMachineIsNotInUse(t *testing.T) {
 		t.Fatal(err)
 	}
 	if len(containers) != 0 || len(listeners) != 0 {
-		t.Errorf("ssh, loopback, name resolution, DHCP and time were counted: %v %v", containers, listeners)
+		t.Errorf("ssh, loopback and the daemons a fresh machine runs were counted: %v %v", containers, listeners)
 	}
 }
 
@@ -163,3 +161,19 @@ func TestARerunWithTheFlagOnAConvergedMachineIsRefused(t *testing.T) {
 		t.Errorf("a converged re-run of a converged machine was refused: %v", err)
 	}
 }
+
+func TestOnlyTheDaemonsTheMeasurementFoundAreQuiet(t *testing.T) {
+	// novox/hq ADR 0101: the exempt daemons are the ones a fresh machine was measured to run —
+	// the resolver and the network manager. A time client or a DHCP client listening beyond
+	// loopback is something somebody put there, and that is a machine in use.
+	sockets := `udp UNCONN 0      0                                          0.0.0.0:123   0.0.0.0:* users:(("systemd-timesyn",pid=260,fd=9))
+udp UNCONN 0      0                                          0.0.0.0:68    0.0.0.0:* users:(("dhcpcd",pid=270,fd=9))
+`
+	_, listeners, err := InUse(context.Background(), inUseRunner{ss: sockets}.run, func(string) bool { return false })
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(listeners) != 2 {
+		t.Errorf("counted %d listener(s), want the time client and the DHCP client: %+v", len(listeners), listeners)
+	}
+}