feat: add method to return name of ns

nshandle_linux.go

@@ -2,6 +2,8 @@ package netns
 
 import (
 	"fmt"
+	"os"
+	"path/filepath"
 
 	"golang.org/x/sys/unix"
 )
@@ -27,6 +29,42 @@ func (ns NsHandle) Equal(other NsHandle) bool {
 	return (s1.Dev == s2.Dev) && (s1.Ino == s2.Ino)
 }
 
+// Name returns the name of the network namespace associated with the
+// handle.
+func (ns NsHandle) Name() (string, error) {
+	if ns == -1 {
+		return "", nil
+	}
+
+	var target unix.Stat_t
+	if err := unix.Fstat(int(ns), &target); err != nil {
+		return "", err
+	}
+
+	// Loop through all the named network namespaces to find the target
+	entries, err := os.ReadDir(bindMountPath)
+	if err != nil {
+		return "", err
+	}
+
+	for _, entry := range entries {
+		name := entry.Name()
+		path := filepath.Join(bindMountPath, name)
+
+		var stat unix.Stat_t
+		if err := unix.Stat(path, &stat); err != nil {
+			continue
+		}
+
+		if stat.Dev == target.Dev && stat.Ino == target.Ino {
+			return name, nil
+		}
+	}
+
+	// The target ns doesn't have a name
+	return "", nil
+}
+
 // String shows the file descriptor number and its dev and inode.
 func (ns NsHandle) String() string {
 	if ns == -1 {

nshandle_linux_test.go

@@ -0,0 +1,31 @@
+package netns_test
+
+import (
+	"testing"
+
+	"github.com/vishvananda/netns"
+)
+
+func TestNsHandle_Name(t *testing.T) {
+	const expectedName = "some-ns-no-one-will-ever-use"
+
+	// Create a new network namespace
+	ns, err := netns.NewNamed(expectedName)
+	if err != nil {
+		t.Fatalf("Failed to create network namespace: %v", err)
+	}
+
+	t.Cleanup(func() {
+		ns.Close()
+		netns.DeleteNamed(expectedName)
+	})
+
+	// Get the name of the network namespace
+	name, err := ns.Name()
+	if err != nil {
+		t.Fatalf("Failed to get network namespace name: %v", err)
+	}
+	if name != expectedName {
+		t.Fatalf("Expected name %q, got %q", expectedName, name)
+	}
+}

nshandle_others.go

@@ -13,6 +13,12 @@ func (ns NsHandle) Equal(_ NsHandle) bool {
 	return false
 }
 
+// Name returns the name of the network namespace associated with the
+// handle. It is only implemented on Linux.
+func (ns NsHandle) Name() string {
+	return ""
+}
+
 // String shows the file descriptor number and its dev and inode.
 // It is only implemented on Linux, and returns "NS(none)" on other
 // platforms.