1 files changed, 87 insertions, 0 deletions
diff --git a/lib/getfilecon.c b/lib/getfilecon.c
new file mode 100644
index 0000000..9506eb8
--- /dev/null
+++ b/lib/getfilecon.c
@@ -0,0 +1,87 @@
+/* wrap getfilecon, lgetfilecon, and fgetfilecon
+   Copyright (C) 2009-2023 Free Software Foundation, Inc.
+
+   This file is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Lesser General Public License as
+   published by the Free Software Foundation; either version 2.1 of the
+   License, or (at your option) any later version.
+
+   This file 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 Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* written by Jim Meyering */
+
+#include <config.h>
+
+#include <selinux/selinux.h>
+
+#include <sys/types.h>
+#include <errno.h>
+#include <string.h>
+
+/* FIXME: remove this once there is an errno-gnu module
+   that guarantees the definition of ENODATA.  */
+#ifndef ENODATA
+# define ENODATA ENOTSUP
+#endif
+
+#undef getfilecon
+#undef lgetfilecon
+#undef fgetfilecon
+int getfilecon (char const *file, char **con);
+int lgetfilecon (char const *file, char **con);
+int fgetfilecon (int fd, char **con);
+
+/* getfilecon, lgetfilecon, and fgetfilecon can all misbehave, be it
+   via an old version of libselinux where these would return 0 and set the
+   result context to NULL, or via a modern kernel+lib operating on a file
+   from a disk whose attributes were set by a kernel from around 2006.
+   In that latter case, the functions return a length of 10 for the
+   "unlabeled" context.  Map both failures to a return value of -1, and
+   set errno to ENOTSUP in the first case, and ENODATA in the latter.  */
+
+static int
+map_to_failure (int ret, char **con)
+{
+  if (ret == 0)
+    {
+      errno = ENOTSUP;
+      return -1;
+    }
+
+  if (ret == 10 && strcmp (*con, "unlabeled") == 0)
+    {
+      freecon (*con);
+      *con = NULL;
+      errno = ENODATA;
+      return -1;
+    }
+
+  return ret;
+}
+
+int
+rpl_getfilecon (char const *file, char **con)
+{
+  int ret = getfilecon (file, con);
+  return map_to_failure (ret, con);
+}
+
+int
+rpl_lgetfilecon (char const *file, char **con)
+{
+  int ret = lgetfilecon (file, con);
+  return map_to_failure (ret, con);
+}
+
+int
+rpl_fgetfilecon (int fd, char**con)
+{
+  int ret = fgetfilecon (fd, con);
+  return map_to_failure (ret, con);
+}