Re: [PATCH] Add _sigsys info to siginfo struct

[Joel Brobecker <brobecker@adacore.com>]

Hi Hannes,

On Mon, Jan 03, 2022 at 07:58:54PM +0100, Hannes Domani via Gdb-patches wrote:
> This patch adds information about _sigsys structure from newer
> kernels, so that $_siginfo decoding can show information about
> _sigsys, making it easier for developers to debug seccomp failures.
> 
> Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=24283

Thanks for the patch.

I'm trusting you for the proper definition of the various fields.
This looks reasonable to me, but before we push this, I'm wondering
what happens when debugging on a kernel which does not support
this feature? Is the data undefined? If yes, do we a precendent
for this already?

> ---
>  gdb/linux-tdep.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/gdb/linux-tdep.c b/gdb/linux-tdep.c
> index 927e69bf1e1..fb2abdd1a21 100644
> --- a/gdb/linux-tdep.c
> +++ b/gdb/linux-tdep.c
> @@ -379,6 +379,13 @@ linux_get_siginfo_type_with_fields (struct gdbarch *gdbarch,
>    append_composite_type_field (type, "si_fd", int_type);
>    append_composite_type_field (sifields_type, "_sigpoll", type);
>  
> +  /* _sigsys */
> +  type = arch_composite_type (gdbarch, NULL, TYPE_CODE_STRUCT);
> +  append_composite_type_field (type, "_call_addr", void_ptr_type);
> +  append_composite_type_field (type, "_syscall", int_type);
> +  append_composite_type_field (type, "_arch", uint_type);
> +  append_composite_type_field (sifields_type, "_sigsys", type);
> +
>    /* struct siginfo */
>    siginfo_type = arch_composite_type (gdbarch, NULL, TYPE_CODE_STRUCT);
>    siginfo_type->set_name (xstrdup ("siginfo"));
> -- 
> 2.34.1
> 

-- 
Joel