Re: PATCH RFA: Permit objcopy -add-section to work with /dev/null

[Nick Clifton <nickc at redhat dot com>]

Hi Ian,

> +	    /* We don't use get_file_size so that we can do
> +	         --add-section .note.GNU_stack=/dev/null
> +	       get_file_size doesn't work on /dev/null.  */

You know this worries me a bit.  If we do not check for ordinary files 
then the user could be tripped up if they accidentally specify some 
special file.  Apart from /dev/null I cannot think of any other file 
that they might reasonably want to use.

Plus you are using /dev/null as a shorthand for creating an empty file 
and referring to that.  Maybe it would just be simpler to enhance the 
--add-section option so that if no filename is specified an empty 
section is created.  Ie:

  --add-section .note.GNU_stack

creates an empty .note.GNU_stack section and:

  --add-section .note.GNU_stack=foo.note

creates a .note.GNU_stack section containing a copy of the contents of 
the foo.note file.


> First, it fails because objcopy silently fails when --add-section is
> used with a zero length file:
>
> 	    size = get_file_size (s + 1);
> 	    if (size < 1)
> 	      {
> 		status = 1;
> 		break;
> 	      }
>
> That just seems like an obvious bug.

Well I would agree that the silently failing is a bug.  Generating a 
warning message but continuing would probably be a more appropriate action.

Cheers
  Nick