nodefs: test Mknod

nodefs/README.md

@@ -50,7 +50,9 @@ Decisions
      reading) are handled automatically. No support for directory
      seeks.
 
-To decide
+To do/To decide
 =========
 
-   * implement remaining file types (exercise Mknod)
+   * decide on a final package name
+
+   * handle less open/create.

nodefs/bridge.go

@@ -100,7 +100,13 @@ func (b *rawBridge) newInode(ctx context.Context, ops Operations, id NodeAttr, p
 		_ = ops.(SymlinkOperations)
 	case fuse.S_IFREG:
 		_ = ops.(FileOperations)
+	case fuse.S_IFIFO, syscall.S_IFSOCK:
+		// no type check necessary: FIFO and SOCK don't go
+		// through FUSE for open/read etc.
+		break
 	default:
+		// Remaining types are char and block devices.  Not
+		// sure how those would work in FUSE
 		log.Panicf("filetype %o unimplemented", id.Mode)
 	}
 

nodefs/simple_test.go

@@ -555,4 +555,37 @@ func TestGetAttrParallel(t *testing.T) {
 	wg.Wait()
 }
 
-// XXX test mknod.
+func TestMknod(t *testing.T) {
+	tc := newTestCase(t, false, false)
+	defer tc.Clean()
+
+	modes := map[string]uint32{
+		"regular": syscall.S_IFREG,
+		"socket":  syscall.S_IFSOCK,
+		"fifo":    syscall.S_IFIFO,
+	}
+
+	for nm, mode := range modes {
+		t.Run(nm, func(t *testing.T) {
+			p := filepath.Join(tc.mntDir, nm)
+			err := syscall.Mknod(p, mode|0755, (8<<8)|0)
+			if err != nil {
+				t.Fatalf("mknod(%s): %v", nm, err)
+			}
+
+			var st syscall.Stat_t
+			if err := syscall.Stat(p, &st); err != nil {
+				got := st.Mode &^ 07777
+				if want := mode; got != want {
+					t.Fatalf("stat(%s): got %o want %o", nm, got, want)
+				}
+			}
+
+			// We could test if the files can be
+			// read/written but: The kernel handles FIFOs
+			// without talking to FUSE at all. Presumably,
+			// this also holds for sockets.  Regular files
+			// are tested extensively elsewhere.
+		})
+	}
+}