bug#8391: chmod setuid & setguid bits

[Ondrej Vasik]

On Mon, 2011-04-04 at 11:04 +0200, Ondrej Vasik wrote:
> Hi,
> On Thu, 2011-03-31 at 14:15 -0600, Eric Blake wrote:
> > On 03/31/2011 01:58 PM, Christian wrote:
> > > Hi Paul,
> > > 
> > > Am 31.03.2011 20:54, schrieb Paul Eggert:
> > >> On 03/31/2011 11:25 AM, Christian wrote:
> > >>> and using "0755" is explicit enough, isn't it ?
> > >> Unfortunately it's not that simple, as having 0755 mean
> > >> something different from 755 would violate the principle
> > >> of least surprise.  Please see the thread starting at
> > >> <http://lists.gnu.org/archive/html/bug-coreutils/2006-07/msg00124.html>.
> > > I read it and I came to the conclusion
> > > 755 should preserve s-bit: OK
> > > 2755 sould set sbit. OK
> > > 0755 should remove sbit, cause it is explicit wanted.
> > > and not doing so is a "lemming behaviour".
> > 
> > No, 0755 is not explicit - it is ambiguous with people that are
> > explicitly using printf %#3o to output a 3-digit octal string with
> > leading 0 - I don't think we can change this.
> 
> I just want to mention recent RH bugzilla report about the same issue -
> https://bugzilla.redhat.com/show_bug.cgi?id=691466 ... one of the ideas
> in this bugzilla is that because of the ambiguity of the 0755 (and
> similars) it would be very good to actually inform user in the case that
> the special bit was not cleared (so only in the case that
> SUID/SGID/sticky bits are set). Maybe only in verbose mode, but I think
> it will be improvement for the current situation. What do you think?
> 
> > But my suggestion of 00755 _is_ explicit - after taking off the leading
> > 0 for specifying octal, you are _still_ left with four octal digits
> > which includes the sticky bit explicitly being set to 0.
> 
> 
> I really like the 00XXX suggestion - do you plan to implement that
> yourself? If you don't have time for writing it but this solution is
> generally acceptable compromise, I could try to prepare a patch for
> that.

Sorry for late patch...
Double zero five octal digits modes cleaning change, with test (and info
documentation clarification) is in attachment.

Greetings,
         Ondrej Vasik

chmod-octal.patch
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