[1.7] Question: how to contrive "mount -c /"

Corinna Vinschen corinna-cygwin@cygwin.com
Mon Dec 15 10:16:00 GMT 2008


On Dec 13 17:06, Fergus wrote:
> Here on XP on a domestic machine I have experienced no problems with 
> standard activities.
> 1.7 seems to install very many fewer .bz2 than 1.5 does (I mean, 00s fewer) 
> but ends up 2GB bigger. What's that about?!
> As we have been warned, mount in 1.7 behaves very differently from 1.5 (and 
> I think it'll turn out to be quite convenient) ... BUT:
> In 1.5 I can put
> 	mount -c /
> in a startup script. Try as I might I have been unable to contrive changing 
> the cygwin path prefix in the same way in 1.7 with various attempts at a 
> line in /etc/fstab such as
> 	none /c cygdrive binary 0 0
> 	none / cygdrive  binary 0 0
> (both wrong, though "mount -m" after "mount -c /" at the keyboard suggests 
> the former should work although I don't understand the c in /c) ; and so in 
> order to contrive this path prefix I always have to start each session with 
> an explicit
> 	mount -c /
> typed to the keyboard.
> Can you tell me whether this can be initiated in /etc/fstab and if so how, 
> please?

I'm sorry, but I'm not sure I really understand from the above what
you're up to and what your exact problem is.

My own entry in /etc/fstab:

  none /mnt cygdrive user,posix=0 0 0

I called `mount -c /' on the command line and it worked:

  $ mount -c /
  $ mount | grep noumount
  C: on /c type ntfs (binary,posix=0,user,noumount)
  D: on /d type vfat (binary,posix=0,user,noumount)

I changed the /etc/fstab entry to

  none / cygdrive user,posix=0 0 0

stopped all Cygwin processes, restarted the shell and I got the right
prefix again:

  $ mount | grep noumount
  C: on /c type ntfs (binary,posix=0,user,noumount)
  D: on /d type vfat (binary,posix=0,user,noumount)

Here's one caveat, which is explicitely described in the default comment
in /etc/fstab as well as in the User's Guide.  Mount points in
/etc/fstab are by default system-wide mount points (or, in mount speak,
"nouser" mount points), if they are not explicitely marked as "user"
mount points in the mount flags.  In contrast to the older Cygwin
releases, a user has NOT the right to override system/nouser mount
points with his/her own /etc/fstab/$USER file, nor with the mount(1)
command.

The idea is to allow system administrators to make sure that several
paths always exist, and users are not allowed to screw those
installation up by overriding existing paths.

Bottom line is, if /etc/fstab contains a cygdrive prefix which is not
marked as "user" mount point, for instance:

  none /mnt cygdrive posix=0 0 0

then the command to change this cygdrive prefix will fail with EPERM:

  $ mount -c /
  mount: /: Operation not permitted


Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Project Co-Leader          cygwin AT cygwin DOT com
Red Hat

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