diff --git a/ext/hbsdctl.rb/hbsdctl.c b/ext/hbsdctl.rb/hbsdctl.c
index e0f31fd..ef39479 100644
--- a/ext/hbsdctl.rb/hbsdctl.c
+++ b/ext/hbsdctl.rb/hbsdctl.c
@@ -1,5 +1,15 @@
 #include <ruby.h>
 #include <libhbsdcontrol.h>
+#include <unistd.h>
+
+static VALUE
+bsd_eError(void)
+{
+  VALUE rb_mBSD = rb_const_get(rb_cObject, rb_intern("BSD")),
+    rb_mControl = rb_const_get(rb_mBSD, rb_intern("Control")),
+    rb_eError = rb_const_get(rb_mControl, rb_intern("Error"));
+  return rb_eError;
+}
 
 static VALUE
 ffi_library_version(VALUE self)
@@ -41,6 +51,9 @@ feature_set(VALUE self, VALUE path, VALUE state)
   char *cpath;
   VALUE name;
 
+  if (getuid() != 0) {
+    rb_raise(bsd_eError(), "This operation requires root privileges.");
+  }
   Check_Type(path, T_STRING);
   Check_Type(state, T_FIXNUM);
   cpath = RSTRING_PTR(path);
@@ -54,10 +67,7 @@ feature_set(VALUE self, VALUE path, VALUE state)
   if (r == 0) {
     return Qtrue;
   } else {
-    VALUE rb_mBSD = rb_const_get(rb_cObject, rb_intern("BSD")),
-          rb_mControl = rb_const_get(rb_mBSD, rb_intern("Control")),
-          rb_eError = rb_const_get(rb_mControl, rb_intern("Error"));
-    rb_raise(rb_eError, "hbsdcontrol_set_feature_state failed");
+    rb_raise(bsd_eError(), "hbsdcontrol_set_feature_state failed");
   }
 }