diff --git a/cache.h b/cache.h
index 99af83a047..818804dad6 100644
--- a/cache.h
+++ b/cache.h
@@ -313,6 +313,7 @@ extern int is_bare_repository(void);
 extern int is_inside_git_dir(void);
 extern char *git_work_tree_cfg;
 extern int is_inside_work_tree(void);
+extern int have_git_dir(void);
 extern const char *get_git_dir(void);
 extern char *get_object_directory(void);
 extern char *get_index_file(void);
diff --git a/environment.c b/environment.c
index 0c6d11f6a0..0693cd9a42 100644
--- a/environment.c
+++ b/environment.c
@@ -80,6 +80,11 @@ int is_bare_repository(void)
 	return is_bare_repository_cfg && !get_git_work_tree();
 }
 
+int have_git_dir(void)
+{
+	return !!git_dir;
+}
+
 const char *get_git_dir(void)
 {
 	if (!git_dir)