[PATCH v3 2/3] realpath: Set errno to ENAMETOOLONG for result larger than PATH_MAX [BZ #28770]

[Andreas Schwab]

On Jan 20 2022, Siddhesh Poyarekar via Libc-alpha wrote:

> diff --git a/stdlib/canonicalize.c b/stdlib/canonicalize.c
> index f36bdf4c76..732dc7ea46 100644
> --- a/stdlib/canonicalize.c
> +++ b/stdlib/canonicalize.c
> @@ -400,8 +400,16 @@ realpath_stk (const char *name, char *resolved,
>  
>  error:
>    *dest++ = '\0';
> -  if (resolved != NULL && dest - rname <= get_path_max ())
> -    rname = strcpy (resolved, rname);
> +  if (resolved != NULL)
> +    {
> +      if (dest - rname <= get_path_max ())
> +	rname = strcpy (resolved, rname);
> +      else
> +	{
> +	  failed = true;
> +	  __set_errno (ENAMETOOLONG);
> +	}
> +    }

Shouldn't that preserve any preexisting error?  I think the result
should only be copied if !failed.

-- 
Andreas Schwab, schwab@linux-m68k.org
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