Re: [PATCH] password: Fix backspace in username prompt

[Lennart Sorensen]

On Mon, Mar 01, 2021 at 10:58:40AM +0300, Egor Ignatov wrote:
> From: Egor Ignatov <egori@altlinux.org>
> 
> Make backspace work in superuser login prompt.
> 
> The problem was that bidi logical to visual ignored BN type,
> so you couldn't print control characters.
> 
> Use grub_printf() 3 times, because a line wrap will cause
> the cursor to get stuck at the end of the terminal line.
> 
> Resolves: #60114
> Signed-off-by: Egor Ignatov <egori@altlinux.org>
> ---
>  grub-core/normal/auth.c    |  4 +++-
>  grub-core/normal/charset.c |  1 +
>  grub-core/term/gfxterm.c   | 11 +++++++++--
>  3 files changed, 13 insertions(+), 3 deletions(-)
> 
> diff --git a/grub-core/normal/auth.c b/grub-core/normal/auth.c
> index 6be678c0d..ffbf6d890 100644
> --- a/grub-core/normal/auth.c
> +++ b/grub-core/normal/auth.c
> @@ -177,7 +177,9 @@ grub_username_get (char buf[], unsigned buf_size)
>         if (cur_len)
>           {
>             cur_len--;
> -           grub_printf ("\b \b");
> +           grub_printf ("\b");
> +           grub_printf (" ");
> +           grub_printf ("\b");
>           }
>         continue;
>       }

Is this the part that the commit message refers to?  I must admit I
am not quite sure why this change makes a difference, but if it does,
perhaps it is important (and non obvious) enough that the code should
actually have a comment explaining it, or someone might come by and
clean it up again later.

-- 
Len Sorensen