Re: [PATCH] sigsegv: Fix build on ppc/musl

[Eric Blake]

On Wed, Mar 09, 2022 at 11:37:14PM -0800, Khem Raj wrote:
> mcontext is not a standard layout so glibc and musl differ sadly.
> 
> Fixes
> ../../m4-1.4.19/lib/sigsegv.c: In function 'sigsegv_handler':                 
>                                                                               
>                                 ../../m4-1.4.19/lib/sigsegv.c:223:75: error: 
> 'mcontext_t' has no member named 'uc_regs'; did you mean 'gregs'?             
>                                                                    223 | #    
> define SIGSEGV_FAULT_STACKPOINTER  ((ucontext_t *) 
> ucp)->uc_mcontext.uc_regs->gregs[1]                                           
>                                                     |                         
>                                                   ^~~~~~~

Thanks for the report.  As this file comes from gnulib, the fix needs
to go there first.

> 
> ---
>  lib/sigsegv.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/lib/sigsegv.c b/lib/sigsegv.c
> index 696a152..fa0c465 100644
> --- a/lib/sigsegv.c
> +++ b/lib/sigsegv.c
> @@ -217,10 +217,10 @@ int libsigsegv_version = LIBSIGSEGV_VERSION;
>  #   define SIGSEGV_FAULT_STACKPOINTER  ((ucontext_t *) 
> ucp)->uc_mcontext.gp_regs[1]
>  #  else /* 32-bit */
>  /* both should be equivalent */
> -#   if 0
> -#    define SIGSEGV_FAULT_STACKPOINTER  ((ucontext_t *) 
> ucp)->uc_mcontext.regs->gpr[1]
> +#   if ! defined __GLIBC__
> +#      define SIGSEGV_FAULT_STACKPOINTER  ((ucontext_t *) 
> ucp)->uc_regs->gregs[1]
>  #   else
> -#    define SIGSEGV_FAULT_STACKPOINTER  ((ucontext_t *) 
> ucp)->uc_mcontext.uc_regs->gregs[1]
> +#      define SIGSEGV_FAULT_STACKPOINTER  ((ucontext_t *) 
> ucp)->uc_mcontext.uc_regs->gregs[1]
>  #   endif
>  #  endif
>  
> -- 
> 2.35.1
> 
> 
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> M4-patches@gnu.org
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-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
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