Hi Andrey, I understand that Cygwin is emulating POSIX permissions (and, yes, we already turn this off using the /etc/fstab). What I don't understand is why it uses "special" permissions and not the standard "read/write" options that are available.
One possibility I just though of: Cygwin uses special permissions in the case where the file is not executable (but readable or readable/writable)? I guess I can see that. I'd still love to hear from anybody who's experienced the vanishing permissions... Thanks! Charles On Tue, Mar 11, 2014 at 8:30 AM, Andrey Repin <anrdae...@yandex.ru> wrote: > Greetings, Charles Plager! > >> Short version: When writing to network drives (and probably local >> ones) as Cygwin is setup by default, we see the permissions being set >> using the ACLs where "creator owner" is given "full control" and >> "creator" group are given "read/execute", but by setting "special >> permissions" instead of just having "full control" or "read/execute" >> set. > >> Why does it not just set "full control" or "read/execute"? > > Cygwin by default mimicking POSIX permission set. > If this behavior is undesirable, You can work around it by letting operating > system control the ACL. > Modify cygdrive entry in /etc/fstab to include noacl option. > Then any files accessed outside direct/implied mounts will have permissions > controlled by OS. > >> Long, slightly different version: When the above permissions get set, >> we sometimes see (sometimes = 1 file in a million or less) a file that >> ends up with no permissions. Owner loses permissions, admin loses >> permissions and so far, IT has only been able to make the file go away >> by reformatting the drive. > >> When we tell Cygwin not to use ACLs (adding the following in >> /etc/fstab), this does not seem to happen (in 100 million or so files >> created). > >> none /cygdrive/ cygdrive binary,posix=0,user,noacl 0 0 > > >> This only seems to happen for files created by Cygwin with the ACL >> permissions (although, to be fair, without Cygwin, I don't know that >> anybody is generating as many files). I'm assuming it isn't Cygwin, >> per say, but rather something that interacts with how Cygwin setup the >> permissions (and given the rarity of the problem it is difficult to >> diagnose more thoroughly. > >> So, to sum up: > >> * Why use special permissions and not default settings when using ACLs? > >> * Anybody else experience files that lose all permissions? Any >> suggestions on resetting the file (short of reformatting the drive)? > >> * Any other hints/insights that might be useful here? > >> Thanks, >> Charles > >> p.s. We see this behavior for Cygwin 1.7.9 and beyond. In 1.7.5, it >> doesn't appear as if the ACLs are used and it acts as if "noacl" is >> set. > > > -- > WBR, > Andrey Repin (anrdae...@yandex.ru) 11.03.2014, <16:08> > > Sorry for my terrible english... > -- 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
