On Thu, Nov 11, 2021 at 7:38 PM Roman Kagan <rvkagan@yandex-team.ru> wrote:

> tcp_chr_recv communicates the specific error condition to the caller via
> errno.  However, after setting it, it may call into some system calls or
> library functions which can clobber the errno.
>
> Avoid this by moving the errno assignment to the end of the function.
>
> Signed-off-by: Roman Kagan <rvkagan@yandex-team.ru>
>

Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>

---
>  chardev/char-socket.c | 14 +++++++-------
>  1 file changed, 7 insertions(+), 7 deletions(-)
>
> diff --git a/chardev/char-socket.c b/chardev/char-socket.c
> index 836cfa0bc2..90054ce58c 100644
> --- a/chardev/char-socket.c
> +++ b/chardev/char-socket.c
> @@ -346,13 +346,6 @@ static ssize_t tcp_chr_recv(Chardev *chr, char *buf,
> size_t len)
>                                       NULL);
>      }
>
> -    if (ret == QIO_CHANNEL_ERR_BLOCK) {
> -        errno = EAGAIN;
> -        ret = -1;
> -    } else if (ret == -1) {
> -        errno = EIO;
> -    }
> -
>      if (msgfds_num) {
>          /* close and clean read_msgfds */
>          for (i = 0; i < s->read_msgfds_num; i++) {
> @@ -381,6 +374,13 @@ static ssize_t tcp_chr_recv(Chardev *chr, char *buf,
> size_t len)
>  #endif
>      }
>
> +    if (ret == QIO_CHANNEL_ERR_BLOCK) {
> +        errno = EAGAIN;
> +        ret = -1;
> +    } else if (ret == -1) {
> +        errno = EIO;
> +    }
> +
>      return ret;
>  }
>
> --
> 2.33.1
>
>
>

-- 
Marc-André Lureau