hst/fs: valid method on underlying interface

Signed-off-by: Ophestra <cat@gensokyo.uk>

hst/fs.go

@@ -13,6 +13,8 @@ import (
 type FilesystemConfig interface {
 	// Type returns the type of this mount point.
 	Type() string
+	// Valid returns whether the configuration is valid.
+	Valid() bool
 	// Target returns the pathname of the mount point in the container.
 	Target() *container.Absolute
 	// Host returns a slice of all host paths used by this mount point.
@@ -60,7 +62,9 @@ type FilesystemConfigJSON struct {
 }
 
 // Valid returns whether the [FilesystemConfigJSON] is valid.
-func (f *FilesystemConfigJSON) Valid() bool { return f != nil && f.FilesystemConfig != nil }
+func (f *FilesystemConfigJSON) Valid() bool {
+	return f != nil && f.FilesystemConfig != nil && f.FilesystemConfig.Valid()
+}
 
 func (f *FilesystemConfigJSON) MarshalJSON() ([]byte, error) {
 	if f == nil || f.FilesystemConfig == nil {

hst/fs_test.go

@@ -144,7 +144,7 @@ func TestFilesystemConfigJSON(t *testing.T) {
 			t.Errorf("Valid: %v, want false", got)
 		}
 
-		if got := (&hst.FilesystemConfigJSON{FilesystemConfig: new(hst.FSBind)}).Valid(); !got {
+		if got := (&hst.FilesystemConfigJSON{FilesystemConfig: &hst.FSBind{Src: m("/etc")}}).Valid(); !got {
 			t.Errorf("Valid: %v, want true", got)
 		}
 	})
@@ -192,6 +192,7 @@ type stubFS struct {
 }
 
 func (s stubFS) Type() string                { return s.typeName }
+func (s stubFS) Valid() bool                 { return false }
 func (s stubFS) Target() *container.Absolute { panic("unreachable") }
 func (s stubFS) Host() []*container.Absolute { panic("unreachable") }
 func (s stubFS) Apply(*container.Ops)        { panic("unreachable") }
@@ -205,6 +206,7 @@ type sCheck struct {
 type fsTestCase struct {
 	name   string
 	fs     hst.FilesystemConfig
+	valid  bool
 	ops    container.Ops
 	target *container.Absolute
 	host   []*container.Absolute
@@ -214,9 +216,17 @@ type fsTestCase struct {
 func checkFs(t *testing.T, fstype string, testCases []fsTestCase) {
 	for _, tc := range testCases {
 		t.Run(tc.name, func(t *testing.T) {
+			t.Run("type", func(t *testing.T) {
 				if got := tc.fs.Type(); got != fstype {
 					t.Errorf("Type: %q, want %q", got, fstype)
 				}
+			})
+
+			t.Run("valid", func(t *testing.T) {
+				if got := tc.fs.Valid(); got != tc.valid {
+					t.Errorf("Valid: %v, want %v", got, tc.valid)
+				}
+			})
 
 			t.Run("ops", func(t *testing.T) {
 				ops := new(container.Ops)

hst/fsbind.go

@@ -27,9 +27,10 @@ type FSBind struct {
 }
 
 func (b *FSBind) Type() string { return FilesystemBind }
+func (b *FSBind) Valid() bool  { return b != nil && b.Src != nil }
 
 func (b *FSBind) Target() *container.Absolute {
-	if b == nil || b.Src == nil {
+	if !b.Valid() {
 		return nil
 	}
 	if b.Dst == nil {
@@ -39,14 +40,14 @@ func (b *FSBind) Target() *container.Absolute {
 }
 
 func (b *FSBind) Host() []*container.Absolute {
-	if b == nil || b.Src == nil {
+	if !b.Valid() {
 		return nil
 	}
 	return []*container.Absolute{b.Src}
 }
 
 func (b *FSBind) Apply(ops *container.Ops) {
-	if b == nil || b.Src == nil {
+	if !b.Valid() {
 		return
 	}
 
@@ -69,7 +70,7 @@ func (b *FSBind) Apply(ops *container.Ops) {
 
 func (b *FSBind) String() string {
 	g := 4
-	if b == nil || b.Src == nil {
+	if !b.Valid() {
 		return "<invalid>"
 	}
 

hst/fsbind_test.go

@@ -9,14 +9,14 @@ import (
 
 func TestFSBind(t *testing.T) {
 	checkFs(t, "bind", []fsTestCase{
-		{"nil", (*hst.FSBind)(nil), nil, nil, nil, "<invalid>"},
+		{"nil", (*hst.FSBind)(nil), false, nil, nil, nil, "<invalid>"},
 
 		{"full", &hst.FSBind{
 			Dst:      m("/dev"),
 			Src:      m("/mnt/dev"),
 			Optional: true,
 			Device:   true,
-		}, container.Ops{&container.BindMountOp{
+		}, true, container.Ops{&container.BindMountOp{
 			Source: m("/mnt/dev"),
 			Target: m("/dev"),
 			Flags:  container.BindWritable | container.BindDevice | container.BindOptional,
@@ -28,7 +28,7 @@ func TestFSBind(t *testing.T) {
 			Src:    m("/mnt/dev"),
 			Write:  true,
 			Device: true,
-		}, container.Ops{&container.BindMountOp{
+		}, true, container.Ops{&container.BindMountOp{
 			Source: m("/mnt/dev"),
 			Target: m("/dev"),
 			Flags:  container.BindWritable | container.BindDevice,
@@ -39,7 +39,7 @@ func TestFSBind(t *testing.T) {
 			Dst:   m("/tmp"),
 			Src:   m("/mnt/tmp"),
 			Write: true,
-		}, container.Ops{&container.BindMountOp{
+		}, true, container.Ops{&container.BindMountOp{
 			Source: m("/mnt/tmp"),
 			Target: m("/tmp"),
 			Flags:  container.BindWritable,
@@ -49,7 +49,7 @@ func TestFSBind(t *testing.T) {
 		{"full no flags", &hst.FSBind{
 			Dst: m("/etc"),
 			Src: m("/mnt/etc"),
-		}, container.Ops{&container.BindMountOp{
+		}, true, container.Ops{&container.BindMountOp{
 			Source: m("/mnt/etc"),
 			Target: m("/etc"),
 		}}, m("/etc"), ms("/mnt/etc"),
@@ -57,7 +57,7 @@ func TestFSBind(t *testing.T) {
 
 		{"nil dst", &hst.FSBind{
 			Src: m("/"),
-		}, container.Ops{&container.BindMountOp{
+		}, true, container.Ops{&container.BindMountOp{
 			Source: m("/"),
 			Target: m("/"),
 		}}, m("/"), ms("/"),

hst/fsephemeral.go

@@ -26,9 +26,10 @@ type FSEphemeral struct {
 }
 
 func (e *FSEphemeral) Type() string { return FilesystemEphemeral }
+func (e *FSEphemeral) Valid() bool  { return e != nil && e.Dst != nil }
 
 func (e *FSEphemeral) Target() *container.Absolute {
-	if e == nil {
+	if !e.Valid() {
 		return nil
 	}
 	return e.Dst
@@ -39,7 +40,7 @@ func (e *FSEphemeral) Host() []*container.Absolute { return nil }
 const fsEphemeralDefaultPerm = os.FileMode(0755)
 
 func (e *FSEphemeral) Apply(ops *container.Ops) {
-	if e == nil || e.Dst == nil {
+	if !e.Valid() {
 		return
 	}
 
@@ -61,7 +62,7 @@ func (e *FSEphemeral) Apply(ops *container.Ops) {
 }
 
 func (e *FSEphemeral) String() string {
-	if e == nil || e.Dst == nil {
+	if !e.Valid() {
 		return "<invalid>"
 	}
 

hst/fsephemeral_test.go

@@ -10,14 +10,14 @@ import (
 
 func TestFSEphemeral(t *testing.T) {
 	checkFs(t, "ephemeral", []fsTestCase{
-		{"nil", (*hst.FSEphemeral)(nil), nil, nil, nil, "<invalid>"},
+		{"nil", (*hst.FSEphemeral)(nil), false, nil, nil, nil, "<invalid>"},
 
 		{"full", &hst.FSEphemeral{
 			Dst:   m("/run/user/65534"),
 			Write: true,
 			Size:  1 << 10,
 			Perm:  0700,
-		}, container.Ops{&container.MountTmpfsOp{
+		}, true, container.Ops{&container.MountTmpfsOp{
 			FSName: "ephemeral",
 			Path:   m("/run/user/65534"),
 			Flags:  syscall.MS_NOSUID | syscall.MS_NODEV,
@@ -26,7 +26,7 @@ func TestFSEphemeral(t *testing.T) {
 		}}, m("/run/user/65534"), nil,
 			"w+ephemeral(-rwx------):/run/user/65534"},
 
-		{"cover ro", &hst.FSEphemeral{Dst: m("/run/nscd")},
+		{"cover ro", &hst.FSEphemeral{Dst: m("/run/nscd")}, true,
 			container.Ops{&container.MountTmpfsOp{
 				FSName: "readonly",
 				Path:   m("/run/nscd"),
@@ -39,7 +39,7 @@ func TestFSEphemeral(t *testing.T) {
 			Dst:   hst.AbsTmp,
 			Write: true,
 			Size:  -1,
-		}, container.Ops{&container.MountTmpfsOp{
+		}, true, container.Ops{&container.MountTmpfsOp{
 			FSName: "ephemeral",
 			Path:   hst.AbsTmp,
 			Flags:  syscall.MS_NOSUID | syscall.MS_NODEV,