[PATCH 1/2] image: Suppress string truncation warning

[Rasmus Villemoes]

On 12/10/2022 21.47, Michal Suchanek wrote:
> In file included from ../tools/imagetool.h:24,
>                  from ../tools/default_image.c:16:
> In function ‘image_set_name’,
>     inlined from ‘image_set_header’ at ../tools/default_image.c:133:2:
> ../include/image.h:786:9: warning: ‘strncpy’ specified bound 32 equals destination size [-Wstringop-truncation]
>   786 |         strncpy(image_get_name(hdr), name, IH_NMLEN);
>       |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 
> There is no standard function that can be used to make the copy without
> a warning.

True, but the compiler does give a way to inform that the destination is
not _supposed_ to be a nul-terminated string.

https://lore.kernel.org/u-boot/dad17a9f-d823-1e8b-3381-53961294521c@prevas.dk/

And our include/linux/compiler_attributes.h indeed already exposes that
__nonstring attribute. Perhaps try applying that to the ih_name member.

It may also be necessary to drop the image_get_name() indirection and
just use hdr->ih_name directly; though gcc obviously sees through it to
account for the size of the destination buffer (otherwise it couldn't
warn), I'm not sure it won't lose that attribute.

Rasmus