Mail Archives: cygwin/2001/01/24/14:49:52
At 01:46 PM 1/24/2001, Earnie Boyd wrote:
>"Larry Hall (RFK Partners, Inc)" wrote:
> >
> > At 11:56 AM 1/24/2001, Ehud Karni wrote:
> > > > cd /
> > > > mkdir e
> > > > mount e: /e
> > > > All is well -- e shows up in both an ls ( as e) and mount (as e: /e).
> > > >
> > > > mount f: /f
> > > > I get the error:
> > > > mount: warning - /f does not exist
> > > > but mount shows
> > > > f: f/ . . .
> > > > and ls doesn't show f.
> > > >
> > > > If I do mkdir f, I get:
> > > > mkdir: cannot make directory `f': File exists
> > >
> > >On UNIX systems, you can NOT mount on non-existing directory.
> > >
> > >I think Cygwin can adopt this behavior and refuse to mount when the
> > >directory is missing. There are 2 ways to accomplish this:
> > > 1. Create the directory (silently or with a message).
> > > 2. Produce an error and do not mount.
> > >The 2nd approach has the possible problem for mounts that was done
> > >previously (saved in the registry) - the mount directory may be erased
> > >by a non Cygwin program. In that case I will produce an error message
> > >every time the DLL try to use this mount, and ignore it (but not
> > >delete it from the registry).
> >
> > This may be an issue. The simple approach for handling this here would
> > be do 1, although one could always see what UNIX/Linux does in these cases
> > too. As I recall, UNIX/Linux simply displays an error if the directory to
> > mount to is removed. I see no real problem with supporting this approach
> > either.
> >
>
>There is no way that I know of to prevent the user from removing the
>directory even if mounted. The user could still use the Windows File
>Explorer or a cmd/command window to remove the directory. To make it
>more difficult I suppose that the mount point directory could be marked
>with the system attribute when mounted and remove the system attribute
>when unmounted. However, this still wouldn't prevent it's removal.
>What I would suggest for this is that if the physical mount point
>directory is removed Cygwin recognizes this and removes the mount entry.
My point was the reverse. On UNIX/Linux, its possible to unmount a
directory, delete the directory, and then attempt to remount it. It
will error. Still, your point is a good one. There is an asymmetry
on Windows since there is nothing that prevents the user from removing
any mounted directory by other means (this you cannot do on UNIX/Linux).
There may be a way to lock the directory to prevent this or do as you
suggest (or some other scheme) but I certainly accept that the UNIX/Linux
mount symantics in this respect don't come for free in Windows/Cygwin
environments. Addressing this whole issue is a nice little project.:-)
>What ever the solution is, the incorrect solution is to create the
>supposed physical directory. Recently, I've been creating a /cygmnt
>directory at the root of each of my drive letters. I then create mount
>points under the /cygmnt. So if I want to have a mount point foo on
>drive D: then I would mkdir D:/cygmnt/foo
> mount -b D:/cygmnt/foo /foo
>The reason I do this is for ease of recognition of what I have mounted
>on what devices.
Right. Automatic creation of the directory, IMO, is worse than the
current behavior. I don't really like the idea although someone may be
able to convince me of at least a specific case where it makes sense.
> >
> > >I don't know the reasons of the Cygwin developers for choosing the
> > >current behavior but I'm sure they had something in mind if they
> > >decided to deviate from standard UNIX practice.
> >
> > Yes, I'm sure there was a reason. It may have just been for "expediency".
> > In any case, its not worth speculating unless someone plans to take up the
> > task.
> >
>
>IIRC, the decision for the warning was because it didn't use to warn or
>error and it was desired not to make it any more difficult. I don't
>remember if Geoff Noer had intentioned it remaining a warning. This
>goes back to 1998 if anyone cares to search the archives.
I doubt it!;-)
Larry Hall lhall AT rfk DOT com
RFK Partners, Inc. http://www.rfk.com
118 Washington Street (508) 893-9779 - RFK Office
Holliston, MA 01746 (508) 893-9889 - FAX
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