1 files changed, 98 insertions, 0 deletions
diff --git a/tests/test-openat.c b/tests/test-openat.c
new file mode 100644
index 00000000..48ca448d
--- /dev/null
+++ b/tests/test-openat.c
@@ -0,0 +1,98 @@
+/* Test that openat works.
+   Copyright (C) 2009-2024 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 <ebb9@byu.net>, 2009.  */
+
+#include <config.h>
+
+#include <fcntl.h>
+
+#include "signature.h"
+SIGNATURE_CHECK (openat, int, (int, char const *, int, ...));
+
+#include <errno.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <unistd.h>
+
+#include "macros.h"
+
+#define BASE "test-openat.t"
+
+#include "test-open.h"
+
+static int dfd = AT_FDCWD;
+
+/* Wrapper around openat to test open behavior.  */
+static int
+do_open (char const *name, int flags, ...)
+{
+  if (flags & O_CREAT)
+    {
+      mode_t mode = 0;
+      va_list arg;
+      va_start (arg, flags);
+
+      /* We have to use PROMOTED_MODE_T instead of mode_t, otherwise GCC 4
+         creates crashing code when 'mode_t' is smaller than 'int'.  */
+      mode = va_arg (arg, PROMOTED_MODE_T);
+
+      va_end (arg);
+      return openat (dfd, name, flags, mode);
+    }
+  return openat (dfd, name, flags);
+}
+
+int
+main ()
+{
+  int result;
+
+  /* Test behaviour for invalid file descriptors.  */
+  {
+    errno = 0;
+    ASSERT (openat (-1, "foo", O_RDONLY) == -1);
+    ASSERT (errno == EBADF);
+  }
+  {
+    close (99);
+    errno = 0;
+    ASSERT (openat (99, "foo", O_RDONLY) == -1);
+    ASSERT (errno == EBADF);
+  }
+
+  /* Basic checks.  */
+  result = test_open (do_open, false);
+  dfd = open (".", O_RDONLY);
+  ASSERT (0 <= dfd);
+  ASSERT (test_open (do_open, false) == result);
+  ASSERT (close (dfd) == 0);
+
+  /* Check that even when *-safer modules are in use, plain openat can
+     land in fd 0.  Do this test last, since it is destructive to
+     stdin.  */
+  ASSERT (close (STDIN_FILENO) == 0);
+  ASSERT (openat (AT_FDCWD, ".", O_RDONLY) == STDIN_FILENO);
+  {
+    dfd = open (".", O_RDONLY);
+    ASSERT (STDIN_FILENO < dfd);
+    ASSERT (chdir ("..") == 0);
+    ASSERT (close (STDIN_FILENO) == 0);
+    ASSERT (openat (dfd, ".", O_RDONLY) == STDIN_FILENO);
+    ASSERT (close (dfd) == 0);
+  }
+  return (result ? result : test_exit_status);
+}