Re: [Xen-devel] [livepatch-build-tools part2 2/6] common: Add is_referenced_section() helper function

[Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>]

On 4/16/19 1:07 PM, Pawel Wieczorkiewicz wrote:
> This function checks if given section has an included corresponding
> RELA section and/or any of the symbols table symbols references the
> section. Section associated symbols are ignored here as there is
> always such a symbol for every section.
>
> Signed-off-by: Pawel Wieczorkiewicz <wipawel@xxxxxxxxx>
> Reviewed-by: Andra-Irina Paraschiv <andraprs@xxxxxxxxxx>
> Reviewed-by: Bjoern Doebel <doebel@xxxxxxxxx>
> Reviewed-by: Norbert Manthey <nmanthey@xxxxxxxxx>
> ---
>   common.c | 22 +++++++++++++++++++++-
>   common.h |  1 +
>   2 files changed, 22 insertions(+), 1 deletion(-)
>
> diff --git a/common.c b/common.c
> index 1fb07cb..c968299 100644
> --- a/common.c
> +++ b/common.c
> @@ -15,7 +15,7 @@
>   
>   int is_rela_section(struct section *sec)
>   {
> -       return (sec->sh.sh_type == SHT_RELA);
> +       return sec && (sec->sh.sh_type == SHT_RELA);
>   }
>   
>   int is_local_sym(struct symbol *sym)
> @@ -270,6 +270,26 @@ int is_standard_section(struct section *sec)
>         }
>   }
>   
> +int is_referenced_section(const struct section *sec, const struct kpatch_elf *kelf)
Let's keep to 80 chars where practical (and throughout the rest of the 
patches).
> +{
> +       struct symbol *sym;
> +
> +       if (is_rela_section(sec->rela) && sec->rela->include)
> +               return true;
> +
> +       list_for_each_entry(sym, &kelf->symbols, list) {
> +               if (!sym->include || !sym->sec)
> +                       continue;
> +               /* Ignore section associated sections */
> +               if (sym->type == STT_SECTION)
> +                       continue;
> +               if (sym->sec->index == sec->index)
> +                       return true;
You can simplify this check to `sym->sec == sec` like the rest of the 
code does.
--
Ross Lagerwall

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