1 files changed, 55 insertions, 0 deletions
diff --git a/lib/unlinkdir.c b/lib/unlinkdir.c
new file mode 100644
index 0000000..e78d3bf
--- /dev/null
+++ b/lib/unlinkdir.c
@@ -0,0 +1,55 @@
+/* unlinkdir.c - determine whether we can unlink directories
+
+   Copyright (C) 2005-2006, 2009-2020 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* Written by Paul Eggert, Jim Meyering, and David Bartley.  */
+
+#include <config.h>
+
+#include "unlinkdir.h"
+#include "priv-set.h"
+#include "root-uid.h"
+#include <unistd.h>
+
+#if ! UNLINK_CANNOT_UNLINK_DIR
+
+/* Return true if we cannot unlink directories, false if we might be
+   able to unlink directories.  */
+
+bool
+cannot_unlink_dir (void)
+{
+  static bool initialized;
+  static bool cannot;
+
+  if (! initialized)
+    {
+# if defined PRIV_SYS_LINKDIR
+      /* We might be able to unlink directories if we cannot
+         determine our privileges, or if we have the
+         PRIV_SYS_LINKDIR privilege.  */
+      cannot = (priv_set_ismember (PRIV_SYS_LINKDIR) == 0);
+# else
+      /* In traditional Unix, only root can unlink directories.  */
+      cannot = (geteuid () != ROOT_UID);
+# endif
+      initialized = true;
+    }
+
+  return cannot;
+}
+
+#endif