Add load_restrictor flag.

pkg/loader/loadrestrictions.go

@@ -19,9 +19,50 @@ package loader
 import (
 	"fmt"
 
+	"github.com/spf13/pflag"
 	"sigs.k8s.io/kustomize/pkg/fs"
 )
 
+//go:generate stringer -type=loadRestrictions
+type loadRestrictions int
+
+const (
+	unknown loadRestrictions = iota
+	rootOnly
+	none
+)
+
+const (
+	flagName = "load_restrictor"
+)
+
+var (
+	flagValue = rootOnly.String()
+	flagHelp  = "if set to '" + none.String() +
+		"', local kustomizations may load files from outside their root. " +
+		"This does, however, break the relocatability of the kustomization."
+)
+
+func AddLoadRestrictionsFlag(set *pflag.FlagSet) {
+	set.StringVar(
+		&flagValue, flagName,
+		rootOnly.String(), flagHelp)
+}
+
+func ValidateLoadRestrictorFlag() (LoadRestrictorFunc, error) {
+	switch flagValue {
+	case rootOnly.String():
+		return RestrictionRootOnly, nil
+	case none.String():
+		return RestrictionNone, nil
+	default:
+		return nil, fmt.Errorf(
+			"illegal flag value --%s %s; legal values: %v",
+			flagName, flagValue,
+			[]string{rootOnly.String(), none.String()})
+	}
+}
+
 type LoadRestrictorFunc func(
 	fs.FileSystem, fs.ConfirmedDir, string) (string, error)