Re: [PATCH v3 08/25] tools/xenstore: make hashtable key and value parameters const

[Julien Grall <julien@xxxxxxx>]

Hi,

On 24/07/2023 12:02, Juergen Gross wrote:
> The key and value are never modified by hashtable code, so they should
> be marked as const.
You wrote this but...

> Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
> ---
> V3:
> - make value const, too.
> ---
>   tools/xenstore/hashtable.c | 7 ++++---
>   tools/xenstore/hashtable.h | 4 ++--
>   2 files changed, 6 insertions(+), 5 deletions(-)
>
> diff --git a/tools/xenstore/hashtable.c b/tools/xenstore/hashtable.c
> index 11f6bf8f15..670dc01003 100644
> --- a/tools/xenstore/hashtable.c
> +++ b/tools/xenstore/hashtable.c
> @@ -11,7 +11,8 @@
>   
>   struct entry
>   {
> -    void *k, *v;
> +    const void *k;
> +    void *v;

... this is not const and ...

>       unsigned int h;
>       struct entry *next;
>   };
> @@ -140,7 +141,7 @@ static int hashtable_expand(struct hashtable *h)
>       return 0;
>   }
>   
> -int hashtable_add(struct hashtable *h, void *k, void *v)
> +int hashtable_add(struct hashtable *h, const void *k, const void *v)
>   {
>       /* This method allows duplicate keys - but they shouldn't be used */
>       unsigned int index;
> @@ -164,7 +165,7 @@ int hashtable_add(struct hashtable *h, void *k, void *v)
>       e->k = k;
>       if (h->flags & HASHTABLE_FREE_KEY)
>           talloc_steal(e, k);
> -    e->v = v;
> +    e->v = (void *)v;
... you cast-away the const here. I think this is a pretty bad idea.

Can you clarify why you are doing like that?

Cheers,

--
Julien Grall