container/initoverlay: configure via fsconfig

This works around the page size limit at the cost of negligible performance regressions.

Closes #34.

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

11 files changed, 124 insertions, 91 deletions

diff --git a/check/overlay.go b/check/overlay.go
index fbbcd1e6..c417e709 100644
--- a/check/overlay.go
+++ b/check/overlay.go
@@ -4,15 +4,23 @@ import "strings"
 
 const (
 	// SpecialOverlayEscape is the escape string for overlay mount options.
+	//
+	// Deprecated: This is no longer used and will be removed in 0.5.
 	SpecialOverlayEscape = `\`
 	// SpecialOverlayOption is the separator string between overlay mount options.
+	//
+	// Deprecated: This is no longer used and will be removed in 0.5.
 	SpecialOverlayOption = ","
 	// SpecialOverlayPath is the separator string between overlay paths.
+	//
+	// Deprecated: This is no longer used and will be removed in 0.5.
 	SpecialOverlayPath = ":"
 )
 
 // EscapeOverlayDataSegment escapes a string for formatting into the data
 // argument of an overlay mount system call.
+//
+// Deprecated: This is no longer used and will be removed in 0.5.
 func EscapeOverlayDataSegment(s string) string {
 	if s == "" {
 		return ""
diff --git a/container/container_test.go b/container/container_test.go
index 41d39f68..1bdc28a1 100644
--- a/container/container_test.go
+++ b/container/container_test.go
@@ -16,6 +16,7 @@ import (
 	"strings"
 	"syscall"
 	"testing"
+	_ "unsafe" // for go:linkname
 
 	"hakurei.app/check"
 	"hakurei.app/command"
@@ -233,6 +234,9 @@ func earlyMnt(mnt ...*vfs.MountInfoEntry) func(*testing.T, context.Context) []*v
 	return func(*testing.T, context.Context) []*vfs.MountInfoEntry { return mnt }
 }
 
+//go:linkname toHost hakurei.app/container.toHost
+func toHost(name string) string
+
 var containerTestCases = []struct {
 	name    string
 	filter  bool
@@ -332,13 +336,15 @@ var containerTestCases = []struct {
 		func(t *testing.T, ctx context.Context) []*vfs.MountInfoEntry {
 			return []*vfs.MountInfoEntry{
 				ent("/", hst.PrivateTmp, "rw", "overlay", "overlay",
-					"rw,lowerdir="+
-						container.InternalToHostOvlEscape(ctx.Value(testVal("lower0")).(*check.Absolute).String())+":"+
-						container.InternalToHostOvlEscape(ctx.Value(testVal("lower1")).(*check.Absolute).String())+
+					"rw"+
+						",lowerdir+="+
+						toHost(ctx.Value(testVal("lower0")).(*check.Absolute).String())+
+						",lowerdir+="+
+						toHost(ctx.Value(testVal("lower1")).(*check.Absolute).String())+
 						",upperdir="+
-						container.InternalToHostOvlEscape(ctx.Value(testVal("upper")).(*check.Absolute).String())+
+						toHost(ctx.Value(testVal("upper")).(*check.Absolute).String())+
 						",workdir="+
-						container.InternalToHostOvlEscape(ctx.Value(testVal("work")).(*check.Absolute).String())+
+						toHost(ctx.Value(testVal("work")).(*check.Absolute).String())+
 						",redirect_dir=nofollow,uuid=on,userxattr"),
 			}
 		},
@@ -388,9 +394,11 @@ var containerTestCases = []struct {
 		func(t *testing.T, ctx context.Context) []*vfs.MountInfoEntry {
 			return []*vfs.MountInfoEntry{
 				ent("/", hst.PrivateTmp, "rw", "overlay", "overlay",
-					"ro,lowerdir="+
-						container.InternalToHostOvlEscape(ctx.Value(testVal("lower0")).(*check.Absolute).String())+":"+
-						container.InternalToHostOvlEscape(ctx.Value(testVal("lower1")).(*check.Absolute).String())+
+					"ro"+
+						",lowerdir+="+
+						toHost(ctx.Value(testVal("lower0")).(*check.Absolute).String())+
+						",lowerdir+="+
+						toHost(ctx.Value(testVal("lower1")).(*check.Absolute).String())+
 						",redirect_dir=nofollow,userxattr"),
 			}
 		},
diff --git a/container/dispatcher.go b/container/dispatcher.go
index e583dc21..4636a469 100644
--- a/container/dispatcher.go
+++ b/container/dispatcher.go
@@ -65,6 +65,8 @@ type syscallDispatcher interface {
 	remount(msg message.Msg, target string, flags uintptr) error
 	// mountTmpfs provides mountTmpfs.
 	mountTmpfs(fsname, target string, flags uintptr, size int, perm os.FileMode) error
+	// mountOverlay provides mountOverlay.
+	mountOverlay(target string, options [][2]string) error
 	// ensureFile provides ensureFile.
 	ensureFile(name string, perm, pperm os.FileMode) error
 	// mustLoopback provides mustLoopback.
@@ -169,6 +171,9 @@ func (direct) remount(msg message.Msg, target string, flags uintptr) error {
 func (k direct) mountTmpfs(fsname, target string, flags uintptr, size int, perm os.FileMode) error {
 	return mountTmpfs(k, fsname, target, flags, size, perm)
 }
+func (k direct) mountOverlay(target string, options [][2]string) error {
+	return mountOverlay(target, options)
+}
 func (direct) ensureFile(name string, perm, pperm os.FileMode) error {
 	return ensureFile(name, perm, pperm)
 }
diff --git a/container/dispatcher_test.go b/container/dispatcher_test.go
index c8a7b492..49631854 100644
--- a/container/dispatcher_test.go
+++ b/container/dispatcher_test.go
@@ -468,6 +468,14 @@ func (k *kstub) mountTmpfs(fsname, target string, flags uintptr, size int, perm
 		stub.CheckArg(k.Stub, "perm", perm, 4))
 }
 
+func (k *kstub) mountOverlay(target string, options [][2]string) error {
+	k.Helper()
+	return k.Expects("mountOverlay").Error(
+		stub.CheckArg(k.Stub, "target", target, 0),
+		stub.CheckArgReflect(k.Stub, "options", options, 1),
+	)
+}
+
 func (k *kstub) ensureFile(name string, perm, pperm os.FileMode) error {
 	k.Helper()
 	return k.Expects("ensureFile").Error(
diff --git a/container/initoverlay.go b/container/initoverlay.go
index 910ce425..e4cb0f5a 100644
--- a/container/initoverlay.go
+++ b/container/initoverlay.go
@@ -4,9 +4,9 @@ import (
 	"encoding/gob"
 	"fmt"
 	"slices"
-	"strings"
 
 	"hakurei.app/check"
+	"hakurei.app/ext"
 	"hakurei.app/fhs"
 )
 
@@ -150,7 +150,7 @@ func (o *MountOverlayOp) early(_ *setupState, k syscallDispatcher) error {
 			if v, err := k.evalSymlinks(o.Upper.String()); err != nil {
 				return err
 			} else {
-				o.upper = check.EscapeOverlayDataSegment(toHost(v))
+				o.upper = toHost(v)
 			}
 		}
 
@@ -158,7 +158,7 @@ func (o *MountOverlayOp) early(_ *setupState, k syscallDispatcher) error {
 			if v, err := k.evalSymlinks(o.Work.String()); err != nil {
 				return err
 			} else {
-				o.work = check.EscapeOverlayDataSegment(toHost(v))
+				o.work = toHost(v)
 			}
 		}
 	}
@@ -168,12 +168,39 @@ func (o *MountOverlayOp) early(_ *setupState, k syscallDispatcher) error {
 		if v, err := k.evalSymlinks(a.String()); err != nil {
 			return err
 		} else {
-			o.lower[i] = check.EscapeOverlayDataSegment(toHost(v))
+			o.lower[i] = toHost(v)
 		}
 	}
 	return nil
 }
 
+// mountOverlay sets up an overlay mount via [ext.FS].
+func mountOverlay(target string, options [][2]string) error {
+	fs, err := ext.OpenFS(SourceOverlay, 0)
+	if err != nil {
+		return err
+	}
+	if err = fs.SetString("source", SourceOverlay); err != nil {
+		_ = fs.Close()
+		return err
+	}
+	for _, option := range options {
+		if err = fs.SetString(option[0], option[1]); err != nil {
+			_ = fs.Close()
+			return err
+		}
+	}
+	if err = fs.SetFlag(OptionOverlayUserxattr); err != nil {
+		_ = fs.Close()
+		return err
+	}
+	if err = fs.Mount(target, 0); err != nil {
+		_ = fs.Close()
+		return err
+	}
+	return fs.Close()
+}
+
 func (o *MountOverlayOp) apply(state *setupState, k syscallDispatcher) error {
 	target := o.Target.String()
 	if !o.noPrefix {
@@ -194,7 +221,7 @@ func (o *MountOverlayOp) apply(state *setupState, k syscallDispatcher) error {
 		}
 	}
 
-	options := make([]string, 0, 4)
+	options := make([][2]string, 0, 2+len(o.lower))
 
 	if o.upper == zeroString && o.work == zeroString { // readonly
 		if len(o.Lower) < 2 {
@@ -205,15 +232,16 @@ func (o *MountOverlayOp) apply(state *setupState, k syscallDispatcher) error {
 		if len(o.Lower) == 0 {
 			return &OverlayArgumentError{OverlayEmptyLower, zeroString}
 		}
-		options = append(options,
-			OptionOverlayUpperdir+"="+o.upper,
-			OptionOverlayWorkdir+"="+o.work)
+		options = append(options, [][2]string{
+			{OptionOverlayUpperdir, o.upper},
+			{OptionOverlayWorkdir, o.work},
+		}...)
+	}
+	for _, lower := range o.lower {
+		options = append(options, [2]string{OptionOverlayLowerdir + "+", lower})
 	}
-	options = append(options,
-		OptionOverlayLowerdir+"="+strings.Join(o.lower, check.SpecialOverlayPath),
-		OptionOverlayUserxattr)
 
-	return k.mount(SourceOverlay, target, FstypeOverlay, 0, strings.Join(options, check.SpecialOverlayOption))
+	return k.mountOverlay(target, options)
 }
 
 func (o *MountOverlayOp) late(*setupState, syscallDispatcher) error { return nil }
diff --git a/container/initoverlay_test.go b/container/initoverlay_test.go
index 30dd3237..f0cde7ff 100644
--- a/container/initoverlay_test.go
+++ b/container/initoverlay_test.go
@@ -97,13 +97,12 @@ func TestMountOverlayOp(t *testing.T) {
 			call("mkdirAll", stub.ExpectArgs{"/sysroot", os.FileMode(0705)}, nil, nil),
 			call("mkdirTemp", stub.ExpectArgs{"/", "overlay.upper.*"}, "overlay.upper.32768", nil),
 			call("mkdirTemp", stub.ExpectArgs{"/", "overlay.work.*"}, "overlay.work.32768", nil),
-			call("mount", stub.ExpectArgs{"overlay", "/sysroot", "overlay", uintptr(0), "" +
-				"upperdir=overlay.upper.32768," +
-				"workdir=overlay.work.32768," +
-				"lowerdir=" +
-				`/host/var/lib/planterette/base/debian\:f92c9052:` +
-				`/host/var/lib/planterette/app/org.chromium.Chromium@debian\:f92c9052,` +
-				"userxattr"}, nil, nil),
+			call("mountOverlay", stub.ExpectArgs{"/sysroot", [][2]string{
+				{"upperdir", "overlay.upper.32768"},
+				{"workdir", "overlay.work.32768"},
+				{"lowerdir+", `/host/var/lib/planterette/base/debian:f92c9052`},
+				{"lowerdir+", `/host/var/lib/planterette/app/org.chromium.Chromium@debian:f92c9052`},
+			}}, nil, nil),
 		}, nil},
 
 		{"short lower ro", &Params{ParentPerm: 0755}, &MountOverlayOp{
@@ -129,11 +128,10 @@ func TestMountOverlayOp(t *testing.T) {
 			call("evalSymlinks", stub.ExpectArgs{"/mnt-root/nix/.ro-store0"}, "/mnt-root/nix/.ro-store0", nil),
 		}, nil, []stub.Call{
 			call("mkdirAll", stub.ExpectArgs{"/nix/store", os.FileMode(0755)}, nil, nil),
-			call("mount", stub.ExpectArgs{"overlay", "/nix/store", "overlay", uintptr(0), "" +
-				"lowerdir=" +
-				"/host/mnt-root/nix/.ro-store:" +
-				"/host/mnt-root/nix/.ro-store0," +
-				"userxattr"}, nil, nil),
+			call("mountOverlay", stub.ExpectArgs{"/nix/store", [][2]string{
+				{"lowerdir+", "/host/mnt-root/nix/.ro-store"},
+				{"lowerdir+", "/host/mnt-root/nix/.ro-store0"},
+			}}, nil, nil),
 		}, nil},
 
 		{"success ro", &Params{ParentPerm: 0755}, &MountOverlayOp{
@@ -147,11 +145,10 @@ func TestMountOverlayOp(t *testing.T) {
 			call("evalSymlinks", stub.ExpectArgs{"/mnt-root/nix/.ro-store0"}, "/mnt-root/nix/.ro-store0", nil),
 		}, nil, []stub.Call{
 			call("mkdirAll", stub.ExpectArgs{"/sysroot/nix/store", os.FileMode(0755)}, nil, nil),
-			call("mount", stub.ExpectArgs{"overlay", "/sysroot/nix/store", "overlay", uintptr(0), "" +
-				"lowerdir=" +
-				"/host/mnt-root/nix/.ro-store:" +
-				"/host/mnt-root/nix/.ro-store0," +
-				"userxattr"}, nil, nil),
+			call("mountOverlay", stub.ExpectArgs{"/sysroot/nix/store", [][2]string{
+				{"lowerdir+", "/host/mnt-root/nix/.ro-store"},
+				{"lowerdir+", "/host/mnt-root/nix/.ro-store0"},
+			}}, nil, nil),
 		}, nil},
 
 		{"nil lower", &Params{ParentPerm: 0700}, &MountOverlayOp{
@@ -219,7 +216,11 @@ func TestMountOverlayOp(t *testing.T) {
 			call("evalSymlinks", stub.ExpectArgs{"/mnt-root/nix/.ro-store"}, "/mnt-root/nix/ro-store", nil),
 		}, nil, []stub.Call{
 			call("mkdirAll", stub.ExpectArgs{"/sysroot/nix/store", os.FileMode(0700)}, nil, nil),
-			call("mount", stub.ExpectArgs{"overlay", "/sysroot/nix/store", "overlay", uintptr(0), "upperdir=/host/mnt-root/nix/.rw-store/.upper,workdir=/host/mnt-root/nix/.rw-store/.work,lowerdir=/host/mnt-root/nix/ro-store,userxattr"}, nil, stub.UniqueError(0)),
+			call("mountOverlay", stub.ExpectArgs{"/sysroot/nix/store", [][2]string{
+				{"upperdir", "/host/mnt-root/nix/.rw-store/.upper"},
+				{"workdir", "/host/mnt-root/nix/.rw-store/.work"},
+				{"lowerdir+", "/host/mnt-root/nix/ro-store"},
+			}}, nil, stub.UniqueError(0)),
 		}, stub.UniqueError(0)},
 
 		{"success single layer", &Params{ParentPerm: 0700}, &MountOverlayOp{
@@ -233,11 +234,11 @@ func TestMountOverlayOp(t *testing.T) {
 			call("evalSymlinks", stub.ExpectArgs{"/mnt-root/nix/.ro-store"}, "/mnt-root/nix/ro-store", nil),
 		}, nil, []stub.Call{
 			call("mkdirAll", stub.ExpectArgs{"/sysroot/nix/store", os.FileMode(0700)}, nil, nil),
-			call("mount", stub.ExpectArgs{"overlay", "/sysroot/nix/store", "overlay", uintptr(0), "" +
-				"upperdir=/host/mnt-root/nix/.rw-store/.upper," +
-				"workdir=/host/mnt-root/nix/.rw-store/.work," +
-				"lowerdir=/host/mnt-root/nix/ro-store," +
-				"userxattr"}, nil, nil),
+			call("mountOverlay", stub.ExpectArgs{"/sysroot/nix/store", [][2]string{
+				{"upperdir", "/host/mnt-root/nix/.rw-store/.upper"},
+				{"workdir", "/host/mnt-root/nix/.rw-store/.work"},
+				{"lowerdir+", "/host/mnt-root/nix/ro-store"},
+			}}, nil, nil),
 		}, nil},
 
 		{"success", &Params{ParentPerm: 0700}, &MountOverlayOp{
@@ -261,16 +262,15 @@ func TestMountOverlayOp(t *testing.T) {
 			call("evalSymlinks", stub.ExpectArgs{"/mnt-root/nix/.ro-store3"}, "/mnt-root/nix/ro-store3", nil),
 		}, nil, []stub.Call{
 			call("mkdirAll", stub.ExpectArgs{"/sysroot/nix/store", os.FileMode(0700)}, nil, nil),
-			call("mount", stub.ExpectArgs{"overlay", "/sysroot/nix/store", "overlay", uintptr(0), "" +
-				"upperdir=/host/mnt-root/nix/.rw-store/.upper," +
-				"workdir=/host/mnt-root/nix/.rw-store/.work," +
-				"lowerdir=" +
-				"/host/mnt-root/nix/ro-store:" +
-				"/host/mnt-root/nix/ro-store0:" +
-				"/host/mnt-root/nix/ro-store1:" +
-				"/host/mnt-root/nix/ro-store2:" +
-				"/host/mnt-root/nix/ro-store3," +
-				"userxattr"}, nil, nil),
+			call("mountOverlay", stub.ExpectArgs{"/sysroot/nix/store", [][2]string{
+				{"upperdir", "/host/mnt-root/nix/.rw-store/.upper"},
+				{"workdir", "/host/mnt-root/nix/.rw-store/.work"},
+				{"lowerdir+", "/host/mnt-root/nix/ro-store"},
+				{"lowerdir+", "/host/mnt-root/nix/ro-store0"},
+				{"lowerdir+", "/host/mnt-root/nix/ro-store1"},
+				{"lowerdir+", "/host/mnt-root/nix/ro-store2"},
+				{"lowerdir+", "/host/mnt-root/nix/ro-store3"},
+			}}, nil, nil),
 		}, nil},
 	})
 
diff --git a/container/path_test.go b/container/path_test.go
index 03406fb0..85e285e2 100644
--- a/container/path_test.go
+++ b/container/path_test.go
@@ -10,7 +10,6 @@ import (
 	"testing"
 	"unsafe"
 
-	"hakurei.app/check"
 	"hakurei.app/vfs"
 )
 
@@ -50,9 +49,6 @@ func TestToHost(t *testing.T) {
 	}
 }
 
-// InternalToHostOvlEscape exports toHost passed to [check.EscapeOverlayDataSegment].
-func InternalToHostOvlEscape(s string) string { return check.EscapeOverlayDataSegment(toHost(s)) }
-
 func TestCreateFile(t *testing.T) {
 	t.Run("nonexistent", func(t *testing.T) {
 		t.Run("mkdir", func(t *testing.T) {
diff --git a/internal/pkg/testdata/main.go b/internal/pkg/testdata/main.go
index f79f7917..564a1736 100644
--- a/internal/pkg/testdata/main.go
+++ b/internal/pkg/testdata/main.go
@@ -14,7 +14,6 @@ import (
 	"strconv"
 	"strings"
 
-	"hakurei.app/check"
 	"hakurei.app/fhs"
 	"hakurei.app/vfs"
 )
@@ -159,43 +158,24 @@ func main() {
 			m.Source != "overlay" || m.FsType != "overlay" {
 			log.Fatal("unexpected root mount entry")
 		}
-		var lowerdir string
+		var lowerdir []string
 		for _, o := range strings.Split(m.FsOptstr, ",") {
-			const lowerdirKey = "lowerdir="
+			const lowerdirKey = "lowerdir+="
 			if strings.HasPrefix(o, lowerdirKey) {
-				lowerdir = o[len(lowerdirKey):]
+				lowerdir = append(lowerdir, o[len(lowerdirKey):])
 			}
 		}
 		if !layers {
-			if filepath.Base(lowerdir) != checksumEmptyDir {
+			if len(lowerdir) != 1 || filepath.Base(lowerdir[0]) != checksumEmptyDir {
 				log.Fatal("unexpected artifact checksum")
 			}
 		} else {
 			ident = "p1t_drXr34i-jZNuxDMLaMOdL6tZvQqhavNafGynGqxOZoXAUTSn7kqNh3Ovv3DT"
 
-			lowerdirsEscaped := strings.Split(lowerdir, ":")
-			lowerdirs := lowerdirsEscaped[:0]
-			// ignore the option separator since it does not appear in ident
-			for i, e := range lowerdirsEscaped {
-				if len(e) > 0 &&
-					e[len(e)-1] == check.SpecialOverlayEscape[0] &&
-					(len(e) == 1 || e[len(e)-2] != check.SpecialOverlayEscape[0]) {
-					// ignore escaped pathname separator since it does not
-					// appear in ident
-
-					e = e[:len(e)-1]
-					if len(lowerdirsEscaped) != i {
-						lowerdirsEscaped[i+1] = e + lowerdirsEscaped[i+1]
-						continue
-					}
-				}
-				lowerdirs = append(lowerdirs, e)
-			}
-
-			if len(lowerdirs) != 2 ||
-				filepath.Base(lowerdirs[0]) != "MGWmEfjut2QE2xPJwTsmUzpff4BN_FEnQ7T0j7gvUCCiugJQNwqt9m151fm9D1yU" ||
-				filepath.Base(lowerdirs[1]) != "nY_CUdiaUM1OL4cPr5TS92FCJ3rCRV7Hm5oVTzAvMXwC03_QnTRfQ5PPs7mOU9fK" {
-				log.Fatalf("unexpected lowerdirs %s", strings.Join(lowerdirs, ", "))
+			if len(lowerdir) != 2 ||
+				filepath.Base(lowerdir[0]) != "MGWmEfjut2QE2xPJwTsmUzpff4BN_FEnQ7T0j7gvUCCiugJQNwqt9m151fm9D1yU" ||
+				filepath.Base(lowerdir[1]) != "nY_CUdiaUM1OL4cPr5TS92FCJ3rCRV7Hm5oVTzAvMXwC03_QnTRfQ5PPs7mOU9fK" {
+				log.Fatalf("unexpected lowerdirs %s", strings.Join(lowerdir, ", "))
 			}
 		}
 	} else {
diff --git a/test/sandbox/case/device.nix b/test/sandbox/case/device.nix
index b9dc4b33..d37768a4 100644
--- a/test/sandbox/case/device.nix
+++ b/test/sandbox/case/device.nix
@@ -237,8 +237,8 @@ in
       (ent "/dri" "/dev/dri" "rw,nosuid" "devtmpfs" "devtmpfs" ignore)
       (ent "/var/tmp" "/var/tmp" "rw,nosuid,nodev,relatime" "ext4" "/dev/vda" "rw")
       (ent "/var/cache" "/var/cache" "rw,nosuid,nodev,relatime" "ext4" "/dev/vda" "rw")
-      (ent "/" "/.hakurei/.ro-store" "rw,relatime" "overlay" "overlay" "ro,lowerdir=/host/nix/.ro-store:/host/nix/.rw-store/upper,redirect_dir=nofollow,userxattr")
-      (ent "/" "/.hakurei/store" "rw,relatime" "overlay" "overlay" "rw,lowerdir=/host/nix/.ro-store:/host/nix/.rw-store/upper,upperdir=/host/tmp/.hakurei-store-rw/upper,workdir=/host/tmp/.hakurei-store-rw/work,redirect_dir=nofollow,userxattr")
+      (ent "/" "/.hakurei/.ro-store" "rw,relatime" "overlay" "overlay" "ro,lowerdir+=/host/nix/.ro-store,lowerdir+=/host/nix/.rw-store/upper,redirect_dir=nofollow,userxattr")
+      (ent "/" "/.hakurei/store" "rw,relatime" "overlay" "overlay" "rw,lowerdir+=/host/nix/.ro-store,lowerdir+=/host/nix/.rw-store/upper,upperdir=/host/tmp/.hakurei-store-rw/upper,workdir=/host/tmp/.hakurei-store-rw/work,redirect_dir=nofollow,userxattr")
       (ent "/etc" ignore "ro,nosuid,nodev,relatime" "ext4" "/dev/vda" "rw")
       (ent "/var/lib/hakurei/u0/a4" "/var/lib/hakurei/u0/a4" "rw,nosuid,nodev,relatime" "ext4" "/dev/vda" "rw")
       (ent ignore "/run/user/65534/pulse/native" "ro,nosuid,nodev,relatime" "ext4" "/dev/vda" "rw")
diff --git a/test/sandbox/case/mapuid.nix b/test/sandbox/case/mapuid.nix
index 8b2a635e..7aa78a9b 100644
--- a/test/sandbox/case/mapuid.nix
+++ b/test/sandbox/case/mapuid.nix
@@ -264,8 +264,8 @@ in
       (ent "/dri" "/dev/dri" "rw,nosuid" "devtmpfs" "devtmpfs" ignore)
       (ent "/var/tmp" "/var/tmp" "rw,nosuid,nodev,relatime" "ext4" "/dev/vda" "rw")
       (ent "/var/cache" "/var/cache" "rw,nosuid,nodev,relatime" "ext4" "/dev/vda" "rw")
-      (ent "/" "/.hakurei/.ro-store" "rw,relatime" "overlay" "overlay" "ro,lowerdir=/host/nix/.ro-store:/host/nix/.rw-store/upper,redirect_dir=nofollow,userxattr")
-      (ent "/" "/.hakurei/store" "rw,relatime" "overlay" "overlay" "rw,lowerdir=/host/nix/.ro-store:/host/nix/.rw-store/upper,upperdir=/host/tmp/.hakurei-store-rw/upper,workdir=/host/tmp/.hakurei-store-rw/work,redirect_dir=nofollow,userxattr")
+      (ent "/" "/.hakurei/.ro-store" "rw,relatime" "overlay" "overlay" "ro,lowerdir+=/host/nix/.ro-store,lowerdir+=/host/nix/.rw-store/upper,redirect_dir=nofollow,userxattr")
+      (ent "/" "/.hakurei/store" "rw,relatime" "overlay" "overlay" "rw,lowerdir+=/host/nix/.ro-store,lowerdir+=/host/nix/.rw-store/upper,upperdir=/host/tmp/.hakurei-store-rw/upper,workdir=/host/tmp/.hakurei-store-rw/work,redirect_dir=nofollow,userxattr")
       (ent "/etc" ignore "ro,nosuid,nodev,relatime" "ext4" "/dev/vda" "rw")
       (ent "/var/lib/hakurei/u0/a3" "/var/lib/hakurei/u0/a3" "rw,nosuid,nodev,relatime" "ext4" "/dev/vda" "rw")
       (ent ignore "/run/user/1000/pulse/native" "ro,nosuid,nodev,relatime" "ext4" "/dev/vda" "rw")
diff --git a/test/sandbox/case/tty.nix b/test/sandbox/case/tty.nix
index 7c00baed..ccd404a9 100644
--- a/test/sandbox/case/tty.nix
+++ b/test/sandbox/case/tty.nix
@@ -270,8 +270,8 @@ in
       (ent "/dri" "/dev/dri" "rw,nosuid" "devtmpfs" "devtmpfs" ignore)
       (ent "/var/tmp" "/var/tmp" "rw,nosuid,nodev,relatime" "ext4" "/dev/vda" "rw")
       (ent "/var/cache" "/var/cache" "rw,nosuid,nodev,relatime" "ext4" "/dev/vda" "rw")
-      (ent "/" "/.hakurei/.ro-store" "rw,relatime" "overlay" "overlay" "ro,lowerdir=/host/nix/.ro-store:/host/nix/.rw-store/upper,redirect_dir=nofollow,userxattr")
-      (ent "/" "/.hakurei/store" "rw,relatime" "overlay" "overlay" "rw,lowerdir=/host/nix/.ro-store:/host/nix/.rw-store/upper,upperdir=/host/tmp/.hakurei-store-rw/upper,workdir=/host/tmp/.hakurei-store-rw/work,redirect_dir=nofollow,uuid=on,userxattr")
+      (ent "/" "/.hakurei/.ro-store" "rw,relatime" "overlay" "overlay" "ro,lowerdir+=/host/nix/.ro-store,lowerdir+=/host/nix/.rw-store/upper,redirect_dir=nofollow,userxattr")
+      (ent "/" "/.hakurei/store" "rw,relatime" "overlay" "overlay" "rw,lowerdir+=/host/nix/.ro-store,lowerdir+=/host/nix/.rw-store/upper,upperdir=/host/tmp/.hakurei-store-rw/upper,workdir=/host/tmp/.hakurei-store-rw/work,redirect_dir=nofollow,uuid=on,userxattr")
       (ent "/etc" ignore "ro,nosuid,nodev,relatime" "ext4" "/dev/vda" "rw")
       (ent "/var/lib/hakurei/u0/a2" "/var/lib/hakurei/u0/a2" "rw,nosuid,nodev,relatime" "ext4" "/dev/vda" "rw")
       (ent ignore "/run/user/65534/pulse/native" "ro,nosuid,nodev,relatime" "ext4" "/dev/vda" "rw")