pkg/bugtool: add a unit test on FindMaps variants

So that this code is triggered via tests and doesn't fail silently if
cilium/ebpf changes its behavior, like suggested in cilium/ebpf#1566.

Signed-off-by: Mahe Tardy <[email protected]>

pkg/bugtool/maps_test.go

@@ -4,17 +4,52 @@
 package bugtool
 
 import (
+	"os"
 	"testing"
 
+	"github.com/cilium/tetragon/pkg/sensors/base"
+	tus "github.com/cilium/tetragon/pkg/testutils/sensors"
 	"github.com/stretchr/testify/assert"
+
+	// needed to register the probe type execve for the base sensor
+	_ "github.com/cilium/tetragon/pkg/sensors/exec"
 )
 
-func TestFindPinnedMaps(t *testing.T) {
+func TestMain(m *testing.M) {
+	ec := tus.TestSensorsRun(m, "SensorBugtool")
+	os.Exit(ec)
+}
+
+func TestFindMaps(t *testing.T) {
 	t.Run("NoSuchFile", func(t *testing.T) {
 		const path = "/sys/fs/bpf/nosuchfile"
 		_, err := FindPinnedMaps(path)
 		assert.Error(t, err)
 		_, err = FindMapsUsedByPinnedProgs(path)
 		assert.Error(t, err)
 	})
+
+	t.Run("BaseSensorMemlock", func(t *testing.T) {
+		tus.LoadSensor(t, base.GetInitialSensor())
+
+		const path = "/sys/fs/bpf/testSensorBugtool"
+		pinnedMaps, err := FindPinnedMaps(path)
+		assert.NoError(t, err)
+		if assert.NotEmpty(t, pinnedMaps) {
+			assert.NotZero(t, pinnedMaps[0].Memlock)
+		}
+
+		mapsUsedByProgs, err := FindMapsUsedByPinnedProgs(path)
+		assert.NoError(t, err)
+		if assert.NotEmpty(t, mapsUsedByProgs) {
+			assert.NotZero(t, mapsUsedByProgs[0].Memlock)
+		}
+
+		allMaps, err := FindAllMaps()
+		assert.NoError(t, err)
+		if assert.NotEmpty(t, allMaps) {
+			assert.NotZero(t, allMaps[0].Memlock)
+		}
+	})
+
 }

pkg/sensors/program/map.go

@@ -131,6 +131,16 @@ func AddGlobalMap(name string) {
 	globalMaps.maps[key] = true
 }
 
+func DeleteGlobMap(name string) {
+	key := name
+	if len(name) > 15 {
+		key = name[:15]
+	}
+	globalMaps.mu.Lock()
+	defer globalMaps.mu.Unlock()
+	delete(globalMaps.maps, key)
+}
+
 // Map holds pointer to Program object as a source of its ebpf object
 // file. We assume all the programs sharing the map have same map
 // definition, so it's ok to use the first program if there's more.
@@ -145,9 +155,6 @@ func AddGlobalMap(name string) {
 //	...
 //	p.PinMap["mapX"] = &mapX
 func mapBuilder(name string, ty MapType, owner bool, lds ...*Program) *Map {
-	if ty == MapTypeGlobal {
-		AddGlobalMap(name)
-	}
 	m := &Map{name, "", lds[0], Idle(), nil, MaxEntries{0, false}, MaxEntries{0, false}, ty, owner}
 	for _, ld := range lds {
 		ld.PinMap[name] = m
@@ -217,6 +224,9 @@ func (m *Map) Unload() error {
 	if m.MapHandle != nil {
 		if !option.Config.KeepSensorsOnExit {
 			m.MapHandle.Unpin()
+			if m.Type == MapTypeGlobal {
+				DeleteGlobMap(m.Name)
+			}
 		}
 		err := m.MapHandle.Close()
 		m.MapHandle = nil
@@ -294,6 +304,9 @@ func (m *Map) LoadOrCreatePinnedMap(pinPath string, mapSpec *ebpf.MapSpec) error
 
 	m.MapHandle = mh
 	m.PinState.RefInc()
+	if m.Type == MapTypeGlobal {
+		AddGlobalMap(m.Name)
+	}
 	return nil
 }