[RFC][PATCH v8 12/20] Use the new DSO finder helper function since we have it

[Adhemerval Zanella]

On 09/02/2021 14:18, Vivek Das Mohapatra via Libc-alpha wrote:
> ---
>  elf/dl-load.c | 43 +++++++++++++++++--------------------------
>  1 file changed, 17 insertions(+), 26 deletions(-)
> 
> diff --git a/elf/dl-load.c b/elf/dl-load.c
> index 780bca99e8..13ac2053b8 100644
> --- a/elf/dl-load.c
> +++ b/elf/dl-load.c
> @@ -2133,35 +2133,26 @@ _dl_map_object (struct link_map *loader, const char *name,
>  #endif
>  
>    /* Look for this name among those already loaded.  */
> -  for (l = GL(dl_ns)[nsid]._ns_loaded; l; l = l->l_next)
> +  l = _dl_find_dso (name, nsid);
> +
> +  if (l != NULL)
>      {
> -      /* If the requested name matches the soname of a loaded object,
> -	 use that object.  Elide this check for names that have not
> -	 yet been opened.  */
> -      if (__glibc_unlikely ((l->l_faked | l->l_removed) != 0))
> -	continue;
> -      if (!_dl_name_match_p (name, l))
> -	{
> -	  const char *soname;
> -
> -	  if (__glibc_likely (l->l_soname_added)
> -	      || l->l_info[DT_SONAME] == NULL)
> -	    continue;
> -
> -	  soname = ((const char *) D_PTR (l, l_info[DT_STRTAB])
> -		    + l->l_info[DT_SONAME]->d_un.d_val);
> -	  if (strcmp (name, soname) != 0)
> -	    continue;
> -
> -	  /* We have a match on a new name -- cache it.  */
> -	  add_name_to_object (l, soname);
> -	  l->l_soname_added = 1;
> -	}
> -
> -      /* We have a match.  */
> +#ifdef SHARED
> +      /* If we are trying to load a DF_GNU_1_UNIQUE flagged DSO which WAS
> +         already opened in the target NS but with RTLD_ISOLATE so it WAS NOT
> +         created as a proxy we need to error out since we cannot satisfy the
> +         DF_GNU_1_UNIQUE is-equivalent-to RTLD_SHARED semantics.  */
> +      if (!(mode & RTLD_ISOLATE) &&
> +          (l->l_ns != LM_ID_BASE) &&
> +          (l->l_gnu_flags_1 & DF_GNU_1_UNIQUE) &&
> +          !l->l_proxy)
> +      {
> +        _dl_signal_error (EEXIST, name, NULL,
> +                          N_("object cannot be demoted to a proxy"));
> +      }
> +#endif
>        return l;

I think this patch should reorganized along with the previous, where
first you refactor the code to use find_dso and *then* add the
required l_proxy change in a subsequent patch.

(There are other patch organization that I think should be changed,
I will get back to them once I finish reviewing the set)

>      }
> -

I usually avoid such spurious change.

>    /* Display information if we are debugging.  */
>    if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_FILES)
>        && loader != NULL)
>