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PiperOrigin-RevId: 194583126
Change-Id: Ica1d8821a90f74e7e745962d71801c598c652463

1 files changed, 156 insertions, 0 deletions

diff --git a/pkg/sentry/kernel/timekeeper_test.go b/pkg/sentry/kernel/timekeeper_test.go
new file mode 100644
index 000000000..08bacba4f
--- /dev/null
+++ b/pkg/sentry/kernel/timekeeper_test.go
@@ -0,0 +1,156 @@
+// Copyright 2018 Google Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package kernel
+
+import (
+	"testing"
+
+	"gvisor.googlesource.com/gvisor/pkg/sentry/context/contexttest"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/platform"
+	sentrytime "gvisor.googlesource.com/gvisor/pkg/sentry/time"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/usage"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/usermem"
+	"gvisor.googlesource.com/gvisor/pkg/syserror"
+)
+
+// mockClocks is a sentrytime.Clocks that simply returns the times in the
+// struct.
+type mockClocks struct {
+	monotonic int64
+	realtime  int64
+}
+
+// Update implements sentrytime.Clocks.Update. It does nothing.
+func (*mockClocks) Update() (monotonicParams sentrytime.Parameters, monotonicOk bool, realtimeParam sentrytime.Parameters, realtimeOk bool) {
+	return
+}
+
+// Update implements sentrytime.Clocks.GetTime.
+func (c *mockClocks) GetTime(id sentrytime.ClockID) (int64, error) {
+	switch id {
+	case sentrytime.Monotonic:
+		return c.monotonic, nil
+	case sentrytime.Realtime:
+		return c.realtime, nil
+	default:
+		return 0, syserror.EINVAL
+	}
+}
+
+// stateTestClocklessTimekeeper returns a test Timekeeper which has not had
+// SetClocks called.
+func stateTestClocklessTimekeeper(tb testing.TB) *Timekeeper {
+	ctx := contexttest.Context(tb)
+	p := platform.FromContext(ctx)
+	fr, err := p.Memory().Allocate(usermem.PageSize, usage.Anonymous)
+	if err != nil {
+		tb.Fatalf("failed to allocate memory: %v", err)
+	}
+	return &Timekeeper{
+		params: NewVDSOParamPage(p, fr),
+	}
+}
+
+func stateTestTimekeeper(tb testing.TB) *Timekeeper {
+	t := stateTestClocklessTimekeeper(tb)
+	t.SetClocks(sentrytime.NewCalibratedClocks())
+	return t
+}
+
+// TestTimekeeperMonotonicZero tests that monotonic time starts at zero.
+func TestTimekeeperMonotonicZero(t *testing.T) {
+	c := &mockClocks{
+		monotonic: 100000,
+	}
+
+	tk := stateTestClocklessTimekeeper(t)
+	tk.SetClocks(c)
+	defer tk.Destroy()
+
+	now, err := tk.GetTime(sentrytime.Monotonic)
+	if err != nil {
+		t.Errorf("GetTime err got %v want nil", err)
+	}
+	if now != 0 {
+		t.Errorf("GetTime got %d want 0", now)
+	}
+
+	c.monotonic += 10
+
+	now, err = tk.GetTime(sentrytime.Monotonic)
+	if err != nil {
+		t.Errorf("GetTime err got %v want nil", err)
+	}
+	if now != 10 {
+		t.Errorf("GetTime got %d want 10", now)
+	}
+}
+
+// TestTimekeeperMonotonicJumpForward tests that monotonic time jumps forward
+// after restore.
+func TestTimekeeperMonotonicForward(t *testing.T) {
+	c := &mockClocks{
+		monotonic: 900000,
+		realtime:  600000,
+	}
+
+	tk := stateTestClocklessTimekeeper(t)
+	tk.restored = true
+	tk.saveMonotonic = 100000
+	tk.saveRealtime = 400000
+	tk.SetClocks(c)
+	defer tk.Destroy()
+
+	// The monotonic clock should jump ahead by 200000 to 300000.
+	//
+	// The new system monotonic time (900000) is irrelevant to what the app
+	// sees.
+	now, err := tk.GetTime(sentrytime.Monotonic)
+	if err != nil {
+		t.Errorf("GetTime err got %v want nil", err)
+	}
+	if now != 300000 {
+		t.Errorf("GetTime got %d want 300000", now)
+	}
+}
+
+// TestTimekeeperMonotonicJumpBackwards tests that monotonic time does not jump
+// backwards when realtime goes backwards.
+func TestTimekeeperMonotonicJumpBackwards(t *testing.T) {
+	c := &mockClocks{
+		monotonic: 900000,
+		realtime:  400000,
+	}
+
+	tk := stateTestClocklessTimekeeper(t)
+	tk.restored = true
+	tk.saveMonotonic = 100000
+	tk.saveRealtime = 600000
+	tk.SetClocks(c)
+	defer tk.Destroy()
+
+	// The monotonic clock should remain at 100000.
+	//
+	// The new system monotonic time (900000) is irrelevant to what the app
+	// sees and we don't want to jump the monotonic clock backwards like
+	// realtime did.
+	now, err := tk.GetTime(sentrytime.Monotonic)
+	if err != nil {
+		t.Errorf("GetTime err got %v want nil", err)
+	}
+	if now != 100000 {
+		t.Errorf("GetTime got %d want 100000", now)
+	}
+}