[RFC] libexecdir

Corinna Vinschen corinna-cygwin@cygwin.com
Thu Jun 20 15:31:00 GMT 2013

On Jun 20 11:17, Christopher Faylor wrote:
> On Thu, Jun 20, 2013 at 05:10:57PM +0200, Corinna Vinschen wrote:
> >On Jun 20 10:19, Christopher Faylor wrote:
> >> On Thu, Jun 20, 2013 at 10:20:51AM +0200, Corinna Vinschen wrote:
> >> >Conflicts like this will happen.  If we change libexec, we have to be
> >> >prepared for this kind of stuff.  Is it worth it?
> >> 
> >> I certainly have gone through this "pain" when the changeover was made
> >> on Linux.  If we want to provide the real Linux look-and-feel I don't
> >> think we have any choice.  :-)
> >> 
> >> But, seriously, I think that the change makes sense in the long run. If
> >> we don't do this we'll eventually just have to be tweaking more and more
> >> configurations to put things in /usr/libexec rather than /usr/lib.
> >
> >Yeah, probably.  Me and my lawn...
> I see you got what I meant even though I got the sense wrong.
> >> On a similar note, what about Fedora (and others) fusion of /usr/bin <> /bin
> >> and /usr/sbin <> /sbin?  Do we want to think about that too?  It would
> >> certainly make sense for Cygwin.  We could get rid of /usr/bin entirely.
> >
> >No, we can't.  Fedora has /usr/bin, /usr/lib and /usr/sbin, while the
> >/bin, /lib, and /sbin paths are just symlinks to their /usr counterparts.
> >This is necessary to maintain hardcode paths, and this will not go away
> >in Fedora for a long time.
> I guess I should have checked before sending the email but my point was
> if we should be eschewing the use of whichever Fedora has gotten rid of.
> You're right that /bin is a symlink.  So should cygport and others now
> be forcing everything into /usr/whatever?

By default prefix is /usr anyway when building packages with cygport.  I
don't see a reason to disable packages from specifing /bin as installation
path.  After all, it's dumped into the same place anyway.

> >For Cygwin we did this fusion anyway since version 1.1 or so, just as
> >mount points and in the other direction.  We were far ahead of time :)
> >
> >Having said that, we could do the same for /sbin vs. /usr/sbin and
> >create an automatic mount point for it as well.
> Although I think they were my idea, I have never really liked the
> automatic mount points.  Couldn't we just use a symlink?

I'm not really loving them either, but the original reason to have
/usr/bin and /usr/lib mount points rather than symlinks is performance.
That was already the case in pre-1.7 Cygwin when we had the automatic
generation of the /usr/bin and /usr/lib mount points in the registry.

Handling mount points is noticably faster than handling symlinks.
Symlinks require to read file content and since /usr/bin is first in
$PATH by default, you get lots and lots of open/read/close calls on the
/usr/bin symlink.  Even if the file is cached, it's probably still
slower than just fetching the mount point from the internal mount table.


Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Maintainer                 cygwin AT cygwin DOT com
Red Hat

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