Persist try snapshot and arm a systemd revert timer

internal/tryapply/tryapply_test.go

@@ -0,0 +1,137 @@
+package tryapply
+
+import (
+	"errors"
+	"os"
+	"reflect"
+	"strings"
+	"testing"
+	"time"
+
+	"git.unkin.net/unkin/tomswall/internal/nftables"
+)
+
+func setup(t *testing.T) *[]string {
+	t.Helper()
+	Dir = t.TempDir()
+	var cmds []string
+	orig := run
+	run = func(name string, args ...string) error {
+		cmds = append(cmds, name+" "+strings.Join(args, " "))
+		return nil
+	}
+	t.Cleanup(func() { run = orig })
+	return &cmds
+}
+
+func arm(t *testing.T, snap *nftables.Snapshot) {
+	t.Helper()
+	unlock, err := Acquire()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer unlock()
+	if err := Arm(snap, 4242, 90*time.Second); err != nil {
+		t.Fatal(err)
+	}
+}
+
+func TestArmPersistsSnapshotAndTimer(t *testing.T) {
+	cmds := setup(t)
+	snap := &nftables.Snapshot{Table: "tomswall", Present: true,
+		Rules: map[string][]nftables.SnapshotRule{"input": {{Tag: "ssh", Exprs: [][]byte{{1, 2, 3}}}}}}
+	arm(t, snap)
+
+	info, err := os.Stat(snapshotPath())
+	if err != nil {
+		t.Fatal(err)
+	}
+	if info.Mode().Perm() != 0o600 {
+		t.Errorf("snapshot mode %v, want 0600", info.Mode().Perm())
+	}
+	p, err := load()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if p.PID != 4242 || !reflect.DeepEqual(p.Snapshot, snap) {
+		t.Errorf("round trip mismatch: %+v", p)
+	}
+	last := (*cmds)[len(*cmds)-1]
+	if !strings.HasPrefix(last, "systemd-run ") || !strings.Contains(last, "--unit "+Unit) ||
+		!strings.Contains(last, "--on-active=90s") || !strings.HasSuffix(last, " revert") {
+		t.Errorf("unexpected arm command %q", last)
+	}
+}
+
+func TestAbsentTableSnapshotRoundTrip(t *testing.T) {
+	setup(t)
+	arm(t, &nftables.Snapshot{Table: "tomswall"})
+	p, err := load()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if p.Snapshot.Present || p.Snapshot.Table != "tomswall" {
+		t.Errorf("absent table not preserved: %+v", p.Snapshot)
+	}
+}
+
+func TestAcquireRefusesWhilePending(t *testing.T) {
+	setup(t)
+	arm(t, &nftables.Snapshot{Table: "tomswall"})
+	if _, err := Acquire(); !errors.Is(err, ErrPending) {
+		t.Fatalf("second try: got %v, want ErrPending", err)
+	}
+}
+
+func TestArmFailureDiscardsSnapshot(t *testing.T) {
+	setup(t)
+	run = func(name string, args ...string) error {
+		if name == "systemd-run" {
+			return errors.New("no systemd")
+		}
+		return nil
+	}
+	unlock, err := Acquire()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer unlock()
+	if err := Arm(&nftables.Snapshot{Table: "tomswall"}, 1, time.Minute); err == nil {
+		t.Fatal("expected arm error")
+	}
+	if _, err := os.Stat(snapshotPath()); !os.IsNotExist(err) {
+		t.Error("snapshot left behind without a revert timer")
+	}
+}
+
+func TestConfirmPendingDisarms(t *testing.T) {
+	cmds := setup(t)
+	arm(t, &nftables.Snapshot{Table: "tomswall"})
+	pid, ok, err := Confirm()
+	if err != nil || !ok || pid != 4242 {
+		t.Fatalf("Confirm = %d, %v, %v", pid, ok, err)
+	}
+	if _, err := os.Stat(snapshotPath()); !os.IsNotExist(err) {
+		t.Error("snapshot not removed")
+	}
+	if last := (*cmds)[len(*cmds)-1]; last != "systemctl stop "+Unit+".timer" {
+		t.Errorf("timer not stopped, last command %q", last)
+	}
+	unlock, err := Acquire()
+	if err != nil {
+		t.Fatalf("new try refused after confirm: %v", err)
+	}
+	unlock()
+}
+
+func TestConfirmAfterRevertFails(t *testing.T) {
+	setup(t)
+	_, ok, err := Confirm()
+	if err != nil || ok {
+		t.Fatalf("Confirm with nothing pending = %v, %v; want not ok", ok, err)
+	}
+	reverted, err := Revert()
+	if err != nil || reverted {
+		t.Fatalf("Revert with nothing pending = %v, %v", reverted, err)
+	}
+}