Re: [bug #25848] chmod fails to clear sgid bit on absolute changes

[Detlev Zundel]

Hello Jim,

> Thanks for the report, but that is the documented behavior:
>
>   info coreutils 'file perm' dir

Ah, oh.  I didn't know this.  This actually violates the principle of
least surprise in my eyes, but hey, if it is documented, I am ok with
it.

Thinking some more about it, isn't the behaviour then wrong by clearing
the set-uid bit?

The doc says:

     If you want to try to clear these bits, you must mention them
  explicitly in a symbolic mode, e.g.:

But if I review my example, then I first set suid+sgid, then do a chmod
0 and suid is still set, but not suid:

address@hidden:tmp[0]$ mkdir foo ; $p/chmod 3777 foo ; ls -ld foo ; $p/chmod 0 
foo ; ls -ld foo
drwxrwsrwt 2 dzu dzu 4096 2009-03-13 15:28 foo
d-----S--- 2 dzu dzu 4096 2009-03-13 15:28 foo

Isn't this still a bug alas the other way round then I originally
thought?

Thanks
  Detlev

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