Hi Eliot, Do you know where I can find documentation or source code that describes the mapping that cygwin implements?
2018-03-28 15:06 GMT+02:00 Eliot Moss <m...@cs.umass.edu>: > On 3/28/2018 3:09 AM, Kjetil Østerås wrote: > > I notice that when I edit and save a file in a windows application this >> file sometimes get the execute file permission set in cygwin. Some windows >> applications do this and some don't. For instance in my setup if i modify >> a >> .c file using Meld then the execute bit is set, however when I modify the >> same file with sublime text 3 then the execute bit is not set. >> >> Why does this happen? and is there anything I can do to prevent windows >> applications from setting the execute bit on my files? >> > > The Windows file permissions (access control) is substantially different > from the Posix model that Cygwin attempts to present. The mapping from > Windows to Posix that Cygwin implements is arguably the best / most > reasonable mapping between the disparate schemes, and has been carefully > refined over time. But it is just a mapping from the underlying scheme. > > So, if some Windows program sets permissions a particular way, that it how > they show up under Cygwin. To answer your question more directly: No, you > can't prevent a Windows program from setting (the underlying access modes > that translate to what is presented as) the execute bit under Cygwin - > short of preventing the programs from accessing the file altogether, > presumably not what you want. > > File access translation is perhaps one of the roughest edges that Cygwin > *tries* to smooth over. I think it does a good job with what it has, but > the Windows scheme is complex and there is no perfect way to do this. > > Note, though, that there is no good way to prevent a Unix program from > setting execute bits on a particular file either (well, the umask, and > possibly ACLs may give you some control if you want to go to the bother). > It's just that Unix programs don't tend to set that bit unless they are > creating an executable. > > Someone more versed in the Windows access control scheme and the intention > of various permissions might be able to clarify why some many Windows > programs think it is a good thing to set the access mode(s) that Cygwin > reflects as the x bit ... > > Regards - Eliot Moss > > -- > 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 > > -- Kjetil Østerås -- 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