Re: chmod g+s ineffective

[Andrey Repin <anrdaemon@yandex.ru>]

Greetings, Norton Allen!

> On 6/29/2022 9:18 AM, Norton Allen wrote:
>> On 6/29/2022 7:39 AM, Andrey Repin wrote:
>>> Greetings, Norton Allen!
>>>
>>>> On one machine I have, chmod g+s fails to set the sticky bit. The >>> command
>>>> does not return any error, but ls -l continues to show the bit not set.
>>>>      $ mkdir foo
>>>>      $ chgrp flight foo
>>>>      $ chmod g+ws foo
>>>>      $ ls -ld foo
>>>>      drwxrwxr-x+ 1 nort flight 0 Jun 29 06:50 foo
>>> ----------------^
>>>
>>> $ getfacl foo
>>
>> I will collect this shortly, but IIRC, getfacl showed it was not set. > I did see it set there under 'flags' on the system that works.

>     nort@EAS-SOFTWAREE1B ~
>     $ ls -ld foo
>     drwxrwxr-x 1 nort flight 0 Jun 29 06:25 foo

>     nort@EAS-SOFTWAREE1B ~
>     $ chmod g+s foo

>     nort@EAS-SOFTWAREE1B ~
>     $ ls -ld foo
>     drwxrwxr-x 1 nort flight 0 Jun 29 06:25 foo

>     nort@EAS-SOFTWAREE1B ~
>     $ getfacl foo
>     # file: foo
>     # owner: nort
>     # group: flight
>     user::rwx
>     group::rwx
>     other::r-x


>>
>>
>>>
>>>> I ran strace, and it looks like the correct system call parameter is >>> getting passed.
>>>> I am curious as to how the sticky bit is implemented.
>>> First see if it was set or not.
>>>
>>>> It isn't obvious what underlying Windows functionality (if any) is >>> applied.
>>> It does. But the big question is, where do you try to do that.
>>> If this is inside Cygwin installation root, then things could work >> more or
>>> less POSIX'y. If this is outside Cygwin root (f.e. in your system >> profile), it
>>> may or may not work completely, depends how did you mount /cygdrive >> prefix.
>>
>> I will confirm (shortly), but I'm pretty sure these tests were done > under vanilla /home (so c:\cygwin64\home)


> Confirmed (as shown above). Tested in /home/nort on directory /home/nort/foo


>>
>>
>>>
>>>> Ah, just checked on a system where this works, and creating a file >>> in the
>>>> directory from the
>>>> command shell does not set the group, so presumably this >>> functionality is
>>>> all within cygwin. That works for my application, except when it >>> doesn't.
>>>> Any suggestions on what I should look for?
>>> Look if you could avoid using +s. Isn't DACL enough?
>>
>> Am I correct that DACL is not available unless I am on a domain? This > is for a field computer, so connection to a domain is generally more > problematic than helpful.
>>

> So is this implemented using DACL under the hood? And is that expected to fail without a domain?

DACL  means "default ACL" or "directory ACL" (which is essentially the same
and meaning ACL's which will be applied to newly created child objects),
as in `setfacl -m 'd:g:flight:rwx,d:m::rwx' dir [...]`.


-- 
With best regards,
Andrey Repin
Friday, July 1, 2022 02:50:30

Sorry for my terrible english...