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

From: Ross Lagerwall <ross.lagerwall@citrix.com>
To: Pawel Wieczorkiewicz <wipawel@amazon.de>, xen-devel@lists.xen.org
Cc: mpohlack@amazon.de, konrad.wilk@oracle.com
Subject: Re: [livepatch-build-tools part2 2/6] common: Add is_referenced_section() helper function
Date: Mon, 29 Apr 2019 16:14:07 +0100	[thread overview]
Message-ID: <3dc69ca8-6c12-65ab-074c-b635bd5bdaeb@citrix.com> (raw)
In-Reply-To: <20190416120716.26269-2-wipawel@amazon.de>

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@amazon.de>
> Reviewed-by: Andra-Irina Paraschiv <andraprs@amazon.com>
> Reviewed-by: Bjoern Doebel <doebel@amazon.de>
> Reviewed-by: Norbert Manthey <nmanthey@amazon.de>
> ---
>   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

_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel