glibc/libio/tst-fclose-unopened.c
Aaron Merey 35dc62de3d Add another test for fclose on an unopened file
Add new file libio/tst-fclose-unopened2.c that tests whether fclose on an
unopened file returns EOF.

This test differs from tst-fclose-unopened.c by ensuring the file's buffer
is allocated prior to double-fclose.  A comment in tst-fclose-unopened.c
now clarifies that it is testing a file with an unallocated buffer.

Calling fclose on unopened files normally causes a use-after-free bug,
however the standard streams are an exception since they are not
deallocated by fclose.

Tested for x86_64.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2024-09-20 10:32:35 -04:00

43 lines
1.5 KiB
C

/* 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>