1 files changed, 42 insertions, 0 deletions
diff --git a/libio/tst-fclose-unopened.c b/libio/tst-fclose-unopened.c
new file mode 100644
index 0000000..4fed2ff
--- /dev/null
+++ b/libio/tst-fclose-unopened.c
@@ -0,0 +1,42 @@
+/* Test using fclose on an unopened file.
+   Copyright (C) 2024 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library 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.
+
+   The GNU C Library 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 the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <stdio.h>
+#include <support/check.h>
+
+/* Verify that fclose on an unopened file returns EOF.  This test uses
+   a file with an unallocated buffer.
+
+   This is not part of the fclose external contract but there are
+   dependencies on this behaviour.  */
+
+static int
+do_test (void)
+{
+  TEST_COMPARE (fclose (stdin), 0);
+
+  /* Attempt to close the unopened file and verify that EOF is returned.
+     Calling fclose on a file twice normally causes a use-after-free bug,
+     however the standard streams are an exception since they are not
+     deallocated by fclose.  */
+  TEST_COMPARE (fclose (stdin), EOF);
+
+  return 0;
+}
+
+#include <support/test-driver.c>