testutils: add DupFD helper

Add a cross-platform DupFD helper and use it from tests.

Signed-off-by: Lorenz Bauer <[email protected]>

internal/testutils/fd_other.go

@@ -0,0 +1,20 @@
+//go:build !windows
+
+package testutils
+
+import (
+	"testing"
+
+	"github.com/go-quicktest/qt"
+
+	"github.com/cilium/ebpf/internal/unix"
+)
+
+func DupFD(tb testing.TB, fd int) int {
+	tb.Helper()
+
+	dup, err := unix.FcntlInt(uintptr(fd), unix.F_DUPFD_CLOEXEC, 1)
+	qt.Assert(tb, qt.IsNil(err))
+
+	return dup
+}

internal/testutils/fd_windows.go

@@ -0,0 +1,17 @@
+package testutils
+
+import (
+	"testing"
+
+	"github.com/cilium/ebpf/internal/efw"
+	"github.com/go-quicktest/qt"
+)
+
+func DupFD(tb testing.TB, fd int) int {
+	tb.Helper()
+
+	dup, err := efw.EbpfDuplicateFd(fd)
+	qt.Assert(tb, qt.IsNil(err))
+
+	return dup
+}

map_test.go

@@ -804,7 +804,7 @@ func TestNewMapInMapFromFD(t *testing.T) {
 	nested := createMapInMap(t, ArrayOfMaps, Array)
 
 	// Do not copy this, use Clone instead.
-	another, err := NewMapFromFD(dupFD(t, nested.FD()))
+	another, err := NewMapFromFD(testutils.DupFD(t, nested.FD()))
 	if err != nil {
 		t.Fatal("Can't create a new nested map from an FD")
 	}
@@ -1388,7 +1388,7 @@ func TestMapFromFD(t *testing.T) {
 
 	// If you're thinking about copying this, don't. Use
 	// Clone() instead.
-	m2, err := NewMapFromFD(dupFD(t, m.FD()))
+	m2, err := NewMapFromFD(testutils.DupFD(t, m.FD()))
 	testutils.SkipIfNotSupported(t, err)
 	if err != nil {
 		t.Fatal(err)

prog_test.go

@@ -592,7 +592,7 @@ func TestProgramFromFD(t *testing.T) {
 
 	// If you're thinking about copying this, don't. Use
 	// Clone() instead.
-	prog2, err := NewProgramFromFD(dupFD(t, prog.FD()))
+	prog2, err := NewProgramFromFD(testutils.DupFD(t, prog.FD()))
 	testutils.SkipIfNotSupported(t, err)
 	if err != nil {
 		t.Fatal(err)
@@ -1087,14 +1087,3 @@ func ExampleProgramSpec_Tag() {
 		fmt.Println("The programs are identical, tag is", tag)
 	}
 }
-
-func dupFD(tb testing.TB, fd int) int {
-	tb.Helper()
-
-	dup, err := unix.FcntlInt(uintptr(fd), unix.F_DUPFD_CLOEXEC, 1)
-	if err != nil {
-		tb.Fatal("Can't dup fd:", err)
-	}
-
-	return dup
-}