btf/validation: add simple enum handling

Add enum btf handling by translating it to tthe corresponding int type.

Signed-off-by: Kornilios Kourtis <[email protected]>

pkg/btf/validation.go

@@ -163,6 +163,24 @@ func getKernelType(arg btf.Type) string {
 		return "union " + union.Name + suffix
 	}
 
+	enum, ok := arg.(*btf.Enum)
+	if ok {
+		prefix := "u"
+		if enum.Signed {
+			prefix = "s"
+		}
+		switch enum.Size {
+		case 1:
+		case 2:
+		case 4:
+		case 8:
+		default:
+			// Not sure what to do here, so just dump the type name
+			return arg.TypeName() + suffix
+		}
+		return fmt.Sprintf("%s%d%s", prefix, 8*enum.Size, suffix)
+	}
+
 	cnst, ok := arg.(*btf.Const)
 	if ok {
 		// NB: ignore const

pkg/btf/validation_test.go

@@ -12,6 +12,7 @@ import (
 
 	"github.com/cilium/ebpf/btf"
 	"github.com/cilium/tetragon/pkg/tracingpolicy"
+	"github.com/stretchr/testify/require"
 )
 
 func expectError(t *testing.T, err error) error {
@@ -79,3 +80,16 @@ func TestSpecs(t *testing.T) {
 		})
 	}
 }
+
+func TestEnum(t *testing.T) {
+	require.Equal(t,
+		getKernelType(&btf.Enum{
+			Size:   2,
+			Signed: false,
+		}), "u16")
+	require.Equal(t,
+		getKernelType(&btf.Enum{
+			Size:   4,
+			Signed: true,
+		}), "s32")
+}