Re: [PATCH V2] util: Remove redundant checks in the openpty()

[Alex Chen]

Hi all,

This patch has been reviewed by Peter. who can help merge it?

Thanks,
Alex

On 2020/11/2 18:55, AlexChen wrote:
> As we can see from the following function call stack, amaster and aslave
> can not be NULL: char_pty_open() -> qemu_openpty_raw() -> openpty().
> In addition, according to the API specification for openpty():
> https://www.gnu.org/software/libc/manual/html_node/Pseudo_002dTerminal-Pairs.html,
> the arguments name, termp and winp can all be NULL, but arguments amaster or 
> aslave
> can not be NULL.
> Finally, amaster and aslave has been dereferenced at the beginning of the 
> openpty().
> So the checks on amaster and aslave in the openpty() are redundant. Remove 
> them.
> 
> Reported-by: Euler Robot <euler.robot@huawei.com>
> Signed-off-by: Alex Chen <alex.chen@huawei.com>
> Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
> ---
>  util/qemu-openpty.c | 7 +++----
>  1 file changed, 3 insertions(+), 4 deletions(-)
> 
> diff --git a/util/qemu-openpty.c b/util/qemu-openpty.c
> index eb17f5b0bc..427f43a769 100644
> --- a/util/qemu-openpty.c
> +++ b/util/qemu-openpty.c
> @@ -80,10 +80,9 @@ static int openpty(int *amaster, int *aslave, char *name,
>              (termp != NULL && tcgetattr(sfd, termp) < 0))
>                  goto err;
> 
> -        if (amaster)
> -                *amaster = mfd;
> -        if (aslave)
> -                *aslave = sfd;
> +        *amaster = mfd;
> +        *aslave = sfd;
> +
>          if (winp)
>                  ioctl(sfd, TIOCSWINSZ, winp);
>