objdump /tmp problems

[Solar Designer]

Hi,

I am cross-posting this in an attempt to avoid duplicate work (which
I've caused with my original report).

On Sat, Jan 13, 2001 at 07:39:37PM +0000, Philip Blundell wrote:
> I think this patch should fix the problem with objdump mentioned in 
> < http://sources.redhat.com/ml/bug-gnu-utils/2001-01/msg00076.html >.  Another 

Yes, thanks.  However, as Marcus Meissner pointed out in reply to
that message (he didn't CC: bug-gnu-utils) the objdump problem has
already been fixed in a later version of binutils (I was checking
the 2.10 release).  Sorry for that. :-(

Now that I've finally checked binutils 2.10.1.0.4, it does indeed
have the objdump and (from a look at the source only) the nlmconv
problems fixed:

2000-05-12  H.J. Lu  <hjl@gnu.org>

        * nlmconv.c (temp_filename): Removed.

        * nlmconv.c (link_inputs): Use make_temp_file () instead of
        choose_temp_base ().
        * objdump.c (display_target_list): Likewise.
        (display_info_table): Likewise.

Basically, it will still re-open the file without O_EXCL, but only
after first creating it safely.  As the directory has the sticky bit
set, the file couldn't have been removed (hopefully, /tmp cleaners
are correct) and this is safe.

Your approach is nicer, though.  I think I'll take the patch (with
some changes, see below) for a distribution.

The ar and objcopy problems (which are less significant) are still in
this new version (confirmed both with strace).

> way to deal with the issue would be to have objdump call _new_bfd directly -- 
> it doesn't actually want to do anything to the BFDs it creates in this 
> situation, other than see if a target can be successfully selected.
> 
> p.
> 
> 2001-01-13  Philip Blundell  <philb@gnu.org>
> 
> 	* objdump.c (display_target_list): Avoid unsafe use of /tmp.
> 	(display_info_table): Likewise.
> 
> Index: objdump.c
> ===================================================================
> RCS file: /cvs/src/src/binutils/objdump.c,v
> retrieving revision 1.32
> diff -u -p -u -r1.32 objdump.c
> --- objdump.c	2001/01/09 20:25:31	1.32
> +++ objdump.c	2001/01/13 19:37:28
> @@ -2645,14 +2645,14 @@ static void
>  display_target_list ()
>  {
>    extern bfd_target *bfd_target_vector[];
> -  char *dummy_name;
>    int t;
>  
> -  dummy_name = make_temp_file (NULL);
>    for (t = 0; bfd_target_vector[t]; t++)
>      {
> +      char dummy_name[] = "/tmp/XXXXXX";

The old code supported $TMPDIR, so I think this should do so as well
(perhaps another wrapper function should be added to choose-temp.c,
which will use $TMPDIR, but return an fd).

> +      int fd = mkstemp(dummy_name);

I believe mkstemp() isn't sufficiently portable for use in binutils,
and that's why there's mkstemps() in libiberty.

Actually, I would prefer a configure check for mkstemp(), as several
systems (currently, the *BSD's) have better implementations in libc.

-- 
/sd