Re: [PATCH v2 0/2] vfs: Define new syscall getumask.

[Theodore Ts'o]

On Wed, Apr 13, 2016 at 09:01:25PM +0000, Mathieu Desnoyers wrote:
> I'm actually discussing 3 separate things here: the umask, sigmask, and
> cpu affinity mask.

The last two are available in /proc/<pid>/status --- which brings up
the question why not just add umask to /proc/<pid>/status?

That way the shared library can read it via /proc/self/status, but
this way it would be possible to look at other process's umask values
this as well.

> >> Another approach to this has been attempted before, adding something
> >> to /proc, although it didn't go anywhere.  See:
> >> 
> >>  http://comments.gmane.org/gmane.linux.kernel/1292109

... and indeed that's what I suggested.  It looks like from the thread
that it petered out due to apathy instead of people not liking the
idea.

One other reason to suggest using a /proc file is that you're not at
the mercy of the glibc folks to wire up a new system call.  (Glibc has
been refusing to wire up getrandom(2), for example.   Grrrr.....)

     	      	      	 	       	   	      - Ted