test/e2e: add netns leak check

Like we do in system tests now check for netns leaks in e2e as well. Now
because things run in parallel and this dir is shared we cannot test
after each test only once per suite. This will be a PITA to debug if
leaks happen as the netns files do not contain the container ID and are
just random bytes (maybe we should change this?)

Fixes #23715

Signed-off-by: Paul Holzinger <pholzing@redhat.com>

test/e2e/common_test.go

@@ -8,6 +8,7 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"io/fs"
 	"math/rand"
 	"net"
 	"net/url"
@@ -138,10 +139,32 @@ const (
 	imageCacheDir = "imagecachedir"
 )
 
+var netnsFiles []fs.DirEntry
+
+func getNetnsDir() string {
+	if isRootless() {
+		var path string
+		if env, ok := os.LookupEnv("XDG_RUNTIME_DIR"); ok {
+			path = env
+		} else {
+			path = fmt.Sprintf("/run/user/%d", os.Getuid())
+		}
+		return filepath.Join(path, "netns")
+	}
+	// root is hard coded to
+	return "/run/netns"
+}
+
 var _ = SynchronizedBeforeSuite(func() []byte {
 	globalTmpDir, err := os.MkdirTemp("", "podman-e2e-")
 	Expect(err).ToNot(HaveOccurred())
 
+	netnsFiles, err = os.ReadDir(getNetnsDir())
+	// dir might not exists which is fine
+	if !errors.Is(err, fs.ErrNotExist) {
+		Expect(err).ToNot(HaveOccurred())
+	}
+
 	// make cache dir
 	ImageCacheDir = filepath.Join(globalTmpDir, imageCacheDir)
 	err = os.MkdirAll(ImageCacheDir, 0700)
@@ -203,6 +226,13 @@ var _ = SynchronizedAfterSuite(func() {
 	timingsFile = nil
 },
 	func() {
+		// perform a netns leak check after all tests run
+		newNetnsFiles, err := os.ReadDir(getNetnsDir())
+		if !errors.Is(err, fs.ErrNotExist) {
+			Expect(err).ToNot(HaveOccurred())
+		}
+		Expect(newNetnsFiles).To(ConsistOf(netnsFiles), "Netns files were leaked")
+
 		testTimings := make(testResultsSorted, 0, 2000)
 		for i := 1; i <= GinkgoT().ParallelTotal(); i++ {
 			f, err := os.Open(fmt.Sprintf("%s/timings-%d", LockTmpDir, i))