On 2 May 2015 at 07:47, Corinna Vinschen <corinna-cyg...@cygwin.com> wrote: > On May 1 17:32, Stephen John Smoogen wrote: >> I downloaded and installed a copy of Windows 10 on a spare system to >> see how Cygwin works. Most of the applications worked similarly to >> what I was testing on my Windows 7 system. However I have run into a >> problem with the screen command. >> >> The first time I run screen the command gives me a standard help >> screen and data. If I type exit to get back to mintty and then >> type screen again.. I get: >> >> Directory '/tmp/uscreens' must have mode 777. >> >> Which after going through the faq and old mailing list was >> something that occurred on FAT partitions. So I went to check the >> install and the file format is NTFS. I then looked at /tmp and >> got >> >> drwx---rwt+ 1 smoog smoog 0 May 1 16:01 uscreens > > You're using a "Microsoft Account", one of those for twhich the primary > group SID is set to the same SID as your user account has. So > uid==gid==the exact same SID. The group "smoog" is NOT a group called > "smoog", it's your user account. This leads to a chicken-egg problem: >
Oooooh that explains a lot. I was figuring there was an issue with my account but I wasn't sure if this was a new one due to Windows 10 preview, or something I didn't know about Windows account systems. [Time to get a book on deep Windows internals and administration.] > Either Cygwin sets the group permissions in the POSIX permission > attributes to the same value as the user permissions, e.g. > > rwxrwxr-x > > then security-sensitive POSIX applications will complain that the > permissions are too wide-open. > > Or, Cygwin sets the group permissions to 0, e.g. > > rwx---r-x > > Then, apparently, screen complains. > > There would be a third way, which is, to spill the "other" permissions > into the group permissions, in my example: > > rwxr-xr-x > > That should work, but needs YA patch to Cygwin and needs some testing. > Bad timing right now (vaca). > > Workaround: Set the primary group to the affected files explicitely to > an existing group which is in your user token. That would typically be > the group "users", e.g. > > chgrp users /tmp/uscreens > > should work, and then you can chmod it and screen should stop > complaining. > Thank you for answering while you are on vacation. I am going to see if a /etc/passwd and /etc/group entry to better fix that long term. > > HTH, > Corinna > > -- > Corinna Vinschen Please, send mails regarding Cygwin to > Cygwin Maintainer cygwin AT cygwin DOT com > Red Hat -- Stephen J Smoogen. -- 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