[LTP] [PATCH v2] close: add test for double close EBADF

[Li Wang]

On Sat, 11 Apr 2026 at 19:04, Jinseok Kim <always.starving0@gmail.com> wrote:
>
> Verify that calling close() on an already closed file descriptor fails
> with EBADF.
>
> This test adds coverage for a common state transition case where a
> previously valid file descriptor becomes invalid after close().
>
> Signed-off-by: Jinseok Kim <always.starving0@gmail.com>
> ---
> Changes in v2:
> - Add additional test coverage to close02 instead of creating a separate
>   close03 test.
> - Link to v1: https://lore.kernel.org/ltp/20260406133134.17238-2-always.starving0@gmail.com
> ---
>  testcases/kernel/syscalls/close/close02.c | 42 ++++++++++++++++++++---
>  1 file changed, 38 insertions(+), 4 deletions(-)
>
> diff --git a/testcases/kernel/syscalls/close/close02.c b/testcases/kernel/syscalls/close/close02.c
> index 617c48237..768361e56 100644
> --- a/testcases/kernel/syscalls/close/close02.c
> +++ b/testcases/kernel/syscalls/close/close02.c
> @@ -5,17 +5,51 @@
>   */
>
>  /*\
> - * Call close(-1) and expects it to return EBADF.
> + * Verify :manpage:`close(2)` failure cases:
> + *
> + * 1) close(-1) returns EBADF.
> + * 2) closing the same fd twice returns EBADF on the second call.
>   */
>
>  #include <errno.h>
> +#include <fcntl.h>
> +
>  #include "tst_test.h"
>
> -static void run(void)
> +enum case_type {
> +       INVALID_FD,
> +       DOUBLE_CLOSE,
> +};
> +
> +static struct tcase {
> +       const char *desc;
> +       enum case_type type;
> +} tcases[] = {
> +       { "close(-1)", INVALID_FD },
> +       { "close same fd twice", DOUBLE_CLOSE },
> +};
> +
> +static void verify_close(unsigned int i)
>  {
> -       TST_EXP_FAIL(close(-1), EBADF);
> +       int fd;
> +       struct tcase *tc = &tcases[i];
> +
> +       switch (tc->type) {
> +       case INVALID_FD:
> +               TST_EXP_FAIL(close(-1), EBADF, "%s", tc->desc);
> +               break;
> +
> +       case DOUBLE_CLOSE:
> +               fd = SAFE_OPEN("close02", O_CREAT, 0600);

According to the open(2) man page, the flags argument must include one
of the access modes: O_RDONLY, O_WRONLY, or O_RDWR.

For example:

  fd = SAFE_OPEN("close02", O_CREAT | O_RDWR, 0600);

With the flag updated to include an access mode (like O_RDWR),
it will look good to me:

Reviewed-by: Li Wang <wangli.ahau@gmail.com>

-- 
Regards,
Li Wang
Email: wangli.ahau@gmail.com