1 files changed, 94 insertions, 0 deletions
diff --git a/lib/faccessat.c b/lib/faccessat.c
new file mode 100644
index 0000000..ac8977c
--- /dev/null
+++ b/lib/faccessat.c
@@ -0,0 +1,94 @@
+/* Check the access rights of a file relative to an open directory.
+   Copyright (C) 2009-2023 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 Eric Blake */
+
+/* If the user's config.h happens to include <unistd.h>, let it include only
+   the system's <unistd.h> here, so that orig_faccessat doesn't recurse to
+   rpl_faccessat.  */
+#define _GL_INCLUDING_UNISTD_H
+#include <config.h>
+
+/* Specification.  */
+#include <unistd.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#undef _GL_INCLUDING_UNISTD_H
+
+#if HAVE_FACCESSAT
+static int
+orig_faccessat (int fd, char const *name, int mode, int flag)
+{
+  return faccessat (fd, name, mode, flag);
+}
+#endif
+
+/* Write "unistd.h" here, not <unistd.h>, otherwise OSF/1 5.1 DTK cc
+   eliminates this include because of the preliminary #include <unistd.h>
+   above.  */
+#include "unistd.h"
+
+#ifndef HAVE_ACCESS
+/* Mingw lacks access, but it also lacks real vs. effective ids, so
+   the gnulib euidaccess module is good enough.  */
+# undef access
+# define access euidaccess
+#endif
+
+#if HAVE_FACCESSAT
+
+int
+rpl_faccessat (int fd, char const *file, int mode, int flag)
+{
+  int result = orig_faccessat (fd, file, mode, flag);
+
+  if (result == 0 && file[strlen (file) - 1] == '/')
+    {
+      struct stat st;
+      result = fstatat (fd, file, &st, 0);
+      if (result == 0 && !S_ISDIR (st.st_mode))
+        {
+          errno = ENOTDIR;
+          return -1;
+        }
+    }
+
+  return result;
+}
+
+#else /* !HAVE_FACCESSAT */
+
+/* Invoke access or euidaccess on file, FILE, using mode MODE, in the directory
+   open on descriptor FD.  If possible, do it without changing the
+   working directory.  Otherwise, resort to using save_cwd/fchdir, then
+   (access|euidaccess)/restore_cwd.  If either the save_cwd or the
+   restore_cwd fails, then give a diagnostic and exit nonzero.
+   Note that this implementation only supports AT_EACCESS, although some
+   native versions also support AT_SYMLINK_NOFOLLOW.  */
+
+# define AT_FUNC_NAME faccessat
+# define AT_FUNC_F1 euidaccess
+# define AT_FUNC_F2 access
+# define AT_FUNC_USE_F1_COND AT_EACCESS
+# define AT_FUNC_POST_FILE_PARAM_DECLS , int mode, int flag
+# define AT_FUNC_POST_FILE_ARGS        , mode
+# include "at-func.c"
+
+#endif