Ken Brown wrote: > On 3/21/2018 6:36 AM, David Allsopp wrote: > > 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? > > If you search the web for "Posix acl mask" you'll find lots of > information. Here's one that seems pretty good: > > https://cs.unc.edu/help-article/posix-acls-in-linux/
Indeed, I got a lot further once I stopped looking for Cygwin-specific info. The most useful part was eventually finding this in the umask(2) man page (http://man7.org/linux/man-pages/man2/umask.2.html): "Alternatively, if the parent directory has a default ACL (see acl(5)), the umask is ignored". Which explains why I was seeing that behaviour, and it was owing to having added my user account (the OPAM+DRA) to the ACL as that of course added w to the mask. Thanks for the help! David -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple
