Re: chmod issue on 3.1.7.

["Kaz Kylheku (Cygwin)" <743-406-3965@kylheku.com>]

On 2020-10-10 09:32, Kaz Kylheku (Cygwin) via Cygwin wrote:
> Hi all,
> 
> Running this Cygwin on a Windows 10 system:
> 
>   0:DESKTOP-K8055OB:~$ uname -a
>   CYGWIN_NT-10.0-WOW DESKTOP-K8055OB 3.1.7(0.340/5/3) 2020-08-22 19:03
> i686 Cygwi
> 
> When a file is created, and permissions set as follows:
> 
>   0:DESKTOP-K8055OB:~$ touch tempfile
>   0:DESKTOP-K8055OB:~$ chmod 03777 tempfile
>   0:DESKTOP-K8055OB:~$ ls -l tempfile
>   -rwsrwsrwt 1 kaz kaz 0 Oct 10 08:59 tempfile
> 
> Then "chmod u=" is not able to clear the owner's permissions to 
> nothing:
> 
>   0:DESKTOP-K8055OB:~$ chmod u= tempfile
>   0:DESKTOP-K8055OB:~$ ls -l tempfile
>   -rwxrwsrwt 1 kaz kaz 0 Oct 10 08:59 tempfile
> 
> As you can see, it has no effect. The expected value is ----rwsrwt.
> 
> I tried both with 64 and 32 bit Cygwin: same deal.
> 
> This is not a problem with the chmod utility.  I ran into this as a 
> failing
> test case against a chmod library function in a programming language.
> 
> http://www.kylheku.com/cgit/txr/tree/tests/018/chmod.tl
> 
> The test cases pass until the "u=", which fails in the same way.
> This does not use the chmod utility.
> 
> It's an issue with the chmod system call.
> 
> This used to work on my older Cygwin installation, which was around 
> 2.5.

Anyone have a clue about this issue?

$ icacls tempfile
tempfile NULL SID:(DENY)(Rc,S,RD,WD)
          BLACKBOX\kaz:(F)
          BLACKBOX\kaz:(RX,W)
          Everyone:(RX,W)

$ getfacl tempfile
# file: tempfile
# owner: kaz
# group: kaz
# flags: -st
user::rwx
group::rwx
other::rwx

$ ls -l tempfile
-rwxrwsrwt 1 kaz kaz 0 Dec 24 13:09 tempfile

$ chmod u= tempfile
$ ls -l tempfile
-rwxrwsrwt 1 kaz kaz 0 Dec 24 13:09 tempfile