fix(adopt): a jail with no network is adopted with none

pkg/engine/appjail/adopt.go

@@ -149,18 +149,10 @@ func inspectJail(ctx context.Context, name string) jailInfo {
 		out, _ := exec.CommandContext(ctx, args[0], args[1:]...).Output()
 		return strings.TrimSpace(string(out))
 	}
-	// last line only: `jail get` prints a header with these flags, `list` doesn't
-	lastLine := func(s string) string {
-		lines := strings.Split(strings.TrimSpace(s), "\n")
-		return lines[len(lines)-1]
-	}
 	info := jailInfo{Name: name, Env: map[string]string{}}
-	if f := strings.Fields(lastLine(run("appjail", "jail", "get", "-HIpt", "--", name, "networks", "network_ip4"))); len(f) >= 2 && f[0] != "-" {
-		info.Network = strings.Split(f[0], ",")[0]
-		if f[1] != "-" {
-			info.Address = strings.Split(f[1], ",")[0]
-		}
-	}
+	// No -H here: on `jail get` it ADDS the header, where on the list
+	// commands below it takes it away.
+	info.Network, info.Address = jailNetwork(run("appjail", "jail", "get", "-Ipt", "--", name, "networks", "network_ip4"))
 	for _, line := range strings.Split(run("appjail", "expose", "list", "-HIpt", name, "hport", "jport", "protocol"), "\n") {
 		if f := strings.Fields(line); len(f) == 3 {
 			info.Exposes = append(info.Exposes, exposeEntry{f[0], f[1], f[2]})
@@ -196,6 +188,22 @@ func inspectJail(ctx context.Context, name string) jailInfo {
 	return info
 }
 
+// jailNetwork reads `appjail jail get -Ipt <jail> networks network_ip4`:
+// the jail's first network and its address there. A jail with no network
+// prints nothing. Read with -H, that was the header alone, and adopt wrote
+// a virtualnet on network "NETWORKS" at address "NETWORK_IP4".
+func jailNetwork(out string) (network, address string) {
+	f := strings.Fields(out)
+	if len(f) < 2 || f[0] == "-" {
+		return "", ""
+	}
+	network = strings.Split(f[0], ",")[0]
+	if f[1] != "-" {
+		address = strings.Split(f[1], ",")[0]
+	}
+	return network, address
+}
+
 // plumbingRe matches the jail parameters appjail itself adds for the
 // virtual network, NAT and exposes; director re-adds them from the spec,
 // so they must not be baked into template.conf.

pkg/engine/appjail/adopt_test.go

@@ -149,3 +149,20 @@ func TestConvertJailQuotesLiteralEnv(t *testing.T) {
 		t.Errorf("reference was quoted:\n%s", spec.Compose)
 	}
 }
+
+// What `jail get -Ipt <jail> networks network_ip4` prints (appjail 5.7.0 on
+// netlab). The header is what -H used to add: read as data, it became a
+// virtualnet on "NETWORKS" at "NETWORK_IP4".
+func TestJailNetwork(t *testing.T) {
+	for _, c := range []struct{ out, network, address string }{
+		{"ajnet 10.0.0.3", "ajnet", "10.0.0.3"},
+		{"ajnet,other 10.0.0.3,10.1.0.2", "ajnet", "10.0.0.3"},
+		{"ajnet -", "ajnet", ""},
+		{"", "", ""},
+		{"- -", "", ""},
+	} {
+		if n, a := jailNetwork(c.out); n != c.network || a != c.address {
+			t.Errorf("%q: got %q %q, want %q %q", c.out, n, a, c.network, c.address)
+		}
+	}
+}