Re: [PATCH] Input: mouse: vsxxxaa: Replace strlcat() with strscpy()

[David Laight]

On Tue,  3 Nov 2026 22:23:18 -0800
Mariia Nikitash <nikitash.mariiaw@xxxxxxxxx> wrote:

> In preparation for removing the deprecated strlcat() API[1], use
> strscpy() to initialize the mouse device name.
> 
> The destination is zero-initialized, and the constant string fits
> within the buffer. Since the return value is unused, this preserves
> the existing behavior.
> 
> Link: https://github.com/KSPP/linux/issues/370 [1]
> Signed-off-by: Mariia Nikitash <nikitash.mariiaw@xxxxxxxxx>
> ---
>  drivers/input/mouse/vsxxxaa.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/input/mouse/vsxxxaa.c b/drivers/input/mouse/vsxxxaa.c
> index 042a17fe81db..b3a0d7ff5738 100644
> --- a/drivers/input/mouse/vsxxxaa.c
> +++ b/drivers/input/mouse/vsxxxaa.c
> @@ -463,8 +463,8 @@ static int vsxxxaa_connect(struct serio *serio, struct serio_driver *drv)
>  
>  	mouse->dev = input_dev;
>  	mouse->serio = serio;
> -	strlcat(mouse->name, "DEC VSXXX-AA/-GA mouse or VSXXX-AB digitizer",
> -		 sizeof(mouse->name));
> +	strscpy(mouse->name, "DEC VSXXX-AA/-GA mouse or VSXXX-AB digitizer",
> +		sizeof(mouse->name));

You might as well use the 2 argument form.
Moreover, if you use strcpy() you'll get a compile-time error if the
string doesn't fit.
strscpy() will truncate and return an errors.

The other question is whether mouse->name even has to be char[].

Personally I think that while there are issues with strlcat()
(mostly to do with its return value), and that there are often
much better (and faster - so sprintf is out) ways of getting
the same result, the deprecation really needs to propose a
sensible alternative (not inlined strlen() + strscpy()).

This case is, of course one of the 'better ways' cases.

David

>  	snprintf(mouse->phys, sizeof(mouse->phys), "%s/input0", serio->phys);
>  
>  	input_dev->name = mouse->name;