bug#13298: 24.3.50; Cannot write backup file; backing up in ~\.emacs.d\%backup%~

[Dmitry Gutov]

On 29.12.2012 18:44, Eli Zaretskii wrote:
> > Date: Sat, 29 Dec 2012 17:55:58 +0400
> > From: Dmitry Gutov <dgutov@yandex.ru>
> > CC: 13298@debbugs.gnu.org
> >
> > On 29.12.2012 17:51, Eli Zaretskii wrote:
> > > > Date: Sat, 29 Dec 2012 17:42:55 +0400
> > > > From: Dmitry Gutov <dgutov@yandex.ru>
> > > > CC: 13298@debbugs.gnu.org
> > > >
> > > > > Can you step with a debugger (e.g., Edebug) through
> > > > > backup-buffer-copy, and see why it errors out?  My crystal ball says
> > > > > it happens because of set-file-extended-attributes, in which case
> > > > > please tell what is the value of extended-attributes argument passed
> > > > > to backup-buffer-copy.
> > > >
> > > > Indeed, it happens after a call to set-file-acl.
> > > >
> > > > ((acl .
> > > > "O:BAG:S-1-5-21-909999172-181315677-756075521-513D:(A;;FA;;;SY)(A;;FA;;;BA)(A;;FA;;;S-1-5-21-909999172-181315677-756075521-1000)")
> > > > (selinux-context nil nil nil nil))
> > >
> > > And if, before the call to set-file-acl inside
> > > set-file-extended-attributes, you evaluate the expression
> > >
> > >     (file-acl filename)
> > >
> > > what does it return?
> >
> > "O:S-1-5-21-909999172-181315677-756075521-1000G:S-1-5-21-909999172-181315677-756075521-513D:(A;;FA;;;SY)(A;;FA;;;BA)(A;;FA;;;S-1-5-21-909999172-181315677-756075521-1000)"
>
> I guess this happens because all of the following:
>
>    . your user is a local Administrator
>
>    . you took ownership of your ~/.emacs.d directory, instead of
>      leaving it owned by the Administrators group

The above is true. But /Users/gutov is owned by SYSTEM, FWIW.

>    . you didn't (or cannot) enable the "take ownership" privilege in
>      your local security policy

This policy's security setting says "Administrators", and my user 
belongs to that group (I'm looking in Local Policies/User Rights 
Assignment, is that right?).

If I want to change the ownership, I open the Advanced Security Settings 
window, switch to the Owner tab, and the Edit button has the "security 
shield" button on it, which I can click, the edit window opens, I can 
make changes and save. All this without logging in as a different user, 
or even seeing the UAC prompt (in Windows Explorer).

Third-party applications might need a UAC prompt for that, I imagine.

> Because of this, the files created inside ~/.emacs.d inherit the
> owner of that directory, i.e. your user-id, while the original file
> that is being backed up had the Administrators group as its owner
> (that's what the "O:BA" part above means).  And because you don't have
> the privileges of taking ownership, the call to set-file-acl fails.
>
> I installed as trunk revision 111369 a set of changes that should fix
> this for you.  Please test.  (I could only approximate the problem on
> my machine, so I cannot be sure the changes indeed fix it.)

It's better, but now I see these messages:

Saving file c:/Users/gutov/.newsrc...
Error: (file-error "Setting ACL" "operation not permitted" 
"c:/Users/gutov/.emacs.d/backups/!drive_c!Users!gutov!.newsrc~")
Wrote c:/Users/gutov/.newsrc
Saving c:/Users/gutov/.newsrc.eld...
Saving file c:/Users/gutov/.newsrc.eld...
Error: (file-error "Setting ACL" "operation not permitted" 
"c:/Users/gutov/.emacs.d/backups/!drive_c!Users!gutov!.newsrc.eld~")
Wrote c:/Users/gutov/.newsrc.eld
Saving c:/Users/gutov/.newsrc.eld...done

Like I described, I don't think my situation is exceptional, so seeing 
the error messages is misleading.