[LTP] [PATCH 3/3] syscalls: select: Verify that data is available to read

[Li Wang]

On Thu, Sep 3, 2020 at 2:40 PM Viresh Kumar <viresh.kumar@linaro.org> wrote:

> select() returns a positive value on success if timeout hasn't happened,
> else returns 0. Check that and send some data to the write file
> descriptor for the same.
>
> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
>
> ---
> Cyril,
>
> Is this what you were looking for ? I am not sure why, but the last
> test (with named pipe) times out all the time.
> ---
>  testcases/kernel/syscalls/select/select01.c | 13 ++++++++++---
>  1 file changed, 10 insertions(+), 3 deletions(-)
>
> diff --git a/testcases/kernel/syscalls/select/select01.c
> b/testcases/kernel/syscalls/select/select01.c
> index 4367e7f3af3f..b3dcf1fff6f3 100644
> --- a/testcases/kernel/syscalls/select/select01.c
> +++ b/testcases/kernel/syscalls/select/select01.c
> @@ -25,24 +25,31 @@ static struct select_info {
>         int nfds;
>         fd_set *readfds;
>         fd_set *writefds;
> +       int *writefd;
>  } tests[] = {
> -       {4, &readfds_reg, NULL},
> -       {5, &readfds_pipe, &writefds_pipe},
> -       {5, &readfds_npipe, &writefds_npipe},
> +       {4, &readfds_reg, NULL, NULL},
> +       {5, &readfds_pipe, &writefds_pipe, &fds_pipe[1]},
> +       {5, &readfds_npipe, &writefds_npipe, &fd_npipe},
>

The 'nfds' should be equal to 'fd + 1', otherwise, it gets timeout as you
mentioned above.

  {7, &readfds_npipe, &writefds_npipe, &fd_npipe}

-- 
Regards,
Li Wang
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