[LTP] close02: add test for double close EBADF

[linuxtestproject.agent@gmail.com]

Hi Jinseok,

On 2026-04-29, Jinseok Kim wrote:
> close02: add test for double close EBADF

> +static void setup(void)
> +{
> +	fd_closed = SAFE_OPEN("close02", O_CREAT | O_RDWR, 0600);
> +	SAFE_CLOSE(fd_closed);
> +}

SAFE_CLOSE(fd_closed) resets fd_closed to -1 (the macro does `fd = -1`
after the close), so both test cases end up calling close(-1). The second
case never exercises the double-close path. Use a local variable to
preserve the fd value:

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

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