Re: Darwin - chmod broken?

[mwoehlke]

Paul Eggert wrote:
> mwoehlke <address@hidden> writes:
> >  10487 chmod    CALL  chmod(0x2800600,0x1a4)
> >  10487 chmod    NAMI  "."
> >  10487 chmod    RET   chmod 0
> >  10487 chmod    CALL  chmod(0x2800600,0x1a4)
> >  10487 chmod    NAMI  "b"
> >  10487 chmod    RET   chmod 0
> >  10487 chmod    CALL  close(0x1)
> >  10487 chmod    RET   close 0
> >  10487 chmod    CALL  exit(0)
> >
> > Does that look right?
>
> No.  It looks like your kernel is busted.  The first chmod sets
> the permissions of "." to 644, i.e., nobody can search it.
> But the second chmod searches "." successfully.

Yup, that's what I'm seeing.

> Are you running this test as root?

Nope.

> > If I am reading 'man 2 chmod' right, the second chmod() is expected
> > to fail with EACCES?
>
> Yes, that's right.  It looks like your operating system is buggy.

Wow... you ain't kidding...

$ ll -d . b
drwxr-xr-x 3 install sstest 512 Sep 27 08:26 .
drwxr-xr-x 2 install sstest 512 Sep 26 15:20 b
$ /bin/chmod a-x . b
$ ll -d . b
drw-r--r-- 3 install sstest 512 Sep 27 08:26 .
drw-r--r-- 2 install sstest 512 Sep 26 15:20 b
$ ll -d . b
drw-r--r-- 3 install sstest 512 Sep 27 08:26 .
drw-r--r-- 2 install sstest 512 Sep 26 15:20 b
$ chmod a+x .
chmod: changing permissions of `.': Permission denied
$ chmod a+x b
chmod: cannot access `b': Permission denied
$ /bin/chmod a+x .
chmod: .: Permission denied
$ ll -d . b
ls: .: Permission denied
ls: b: Permission denied
$

WTF just happened there?! :-)

Apparently the permissions are being cached and not flushed immediately 
as far as access control, but are being returned accurately for 'ls'... 
that's pretty messed up. So I guess this failure is a red herring at 
least as far as anything being wrong with coreutils. Wow, that's a 
broken OS/kernel/driver/one-of-the-above... (Might be the NFS driver, 
since this didn't break when run on a local mount.)

> Can you reproduce this bug with /bin/chmod?

Yup (See above).

I'll investigate the other failures, but if I can demonstrate that a: 
the OS is broken, and b: the OS's version of the same utility is 
similarly broken, I'll just leave my reports at that (unless someone 
objects to this plan).

Anyway, thanks for all the help!

--
Matthew
The hippo made me do it! What? What do you mean you can't see the hippo?