Re: [PATCH 4/4] io: Reorganize the getcwd implementation

[Adhemerval Zanella <adhemerval.zanella@linaro.org>]

On 27/08/2020 09:35, Adhemerval Zanella wrote:
> diff --git a/elf/dl-object.c b/elf/dl-object.c
> index d2cdf135cc..aab7265717 100644
> --- a/elf/dl-object.c
> +++ b/elf/dl-object.c
> @@ -202,30 +202,12 @@ _dl_new_object (char *realname, const char *libname, int type,
>  	}
>        else
>  	{
> -	  size_t len = realname_len;
> -	  char *result = NULL;
> -
> -	  /* Get the current directory name.  */
> -	  origin = NULL;
> -	  do
> -	    {
> -	      char *new_origin;
> -
> -	      len += 128;
> -	      new_origin = (char *) realloc (origin, len);
> -	      if (new_origin == NULL)
> -		/* We exit the loop.  Note that result == NULL.  */
> -		break;
> -	      origin = new_origin;
> -	    }
> -	  while ((result = __getcwd (origin, len - realname_len)) == NULL
> -		 && errno == ERANGE);
> -
> -	  if (result == NULL)
> +	  /* The rtld __getcwd implementation does not handle paths larger
> +	     than PATH_MAX (which would be invalid to be used on subsequent
> +	     open calls).  */
> +	  origin = __getcwd (NULL, 0);
> +	  if (origin == NULL)
>  	    {
> -	      /* We were not able to determine the current directory.
> -		 Note that free(origin) is OK if origin == NULL.  */
> -	      free (origin);
>  	      origin = (char *) -1;
>  	      goto out;
>  	    }

And this part is obviously wrong since the algorithm will append the realname
on the resulting string afterward.  I will send a update version with the
rtld code size optimization, but without this bogus change.