RE: umask not working?

[David Allsopp <David dot Allsopp at cl dot cam dot ac dot uk>]

Ken Brown
> On 3/19/2018 8:48 AM, David Allsopp wrote:
> > Is this expected behaviour:
> >
> > OPAM+DRA@OPAM ~
> > $ uname -a ; umask ; touch /tmp/foo ; ls -l /tmp/foo ; mkdir /tmp/bar
> > ; touch /tmp/bar/foo ; ls -l /tmp/bar/foo CYGWIN_NT-6.1-WOW OPAM
> > 2.10.0(0.325/5/3) 2018-02-02 15:21 i686 Cygwin
> > 0022
> > -rw-r--r-- 1 OPAM+DRA OPAM+None 0 Mar 19 13:44 /tmp/foo
> > -rw-rw-r--+ 1 OPAM+DRA OPAM+None 0 Mar 19 13:44 /tmp/bar/foo
> >
> > Why does the file /tmp/bar/foo get g+w when /tmp/foo doesn't - I'm not
> > sure what to look at on my system to diagnose what I may have
> > inadvertently tweaked. The directory itself is:
> >
> > drwxr-xr-x+ 1 OPAM+DRA OPAM+None 0 Mar 19 13:44 /tmp/bar
> 
> See if this helps:
> 
>    https://cygwin.com/faq/faq.html#faq.using.same-with-permissions

Thanks for the pointer. I wonder from it if this could be to do with the Cygwin installation being old (but upgraded). I tried on the same machine creating another installation to C:\cygwin2 (which behaves as Roger Wells noted) and then ran getfacl /tmp on each:

Old installation:

# file: /tmp
# owner: OPAM+DRA-Admin
# group: OPAM+None
user::rwx
user:OPAM+DRA:rwx
group::r-x
mask:rwx
other:r-x
default:user::rwx
default:user:OPAM+DRA:rwx
default:group::r-x
default:mask:rwx
default:other:r-x

Fresh installation:

# file: /tmp
# owner: OPAM+DRA-Admin
# group: OPAM+None
# flags: --t
user::rwx
group::rwx
other:rwx
default:user::rwx
default:group::r-x
default:other:r-x

I expect that the extra OPAM+DRA:rwx on the old installation was manually added by me, years ago. What are the "mask" entries all about?

The default:mask entry seems to be the crucial one, as if I do setfacl default:mask:rwx /tmp on the fresh installation, then I get the same behaviour as on the old installation.

However, I'm struggling to find references for either what these mask entries are, or how they ever appeared?

Thanks!


David