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A translator for faking privileged access to an underlying filesystem.

This translator appears to give transparent access to the underlying
directory node.  However, all accesses are made using the credentials
of the translator regardless of the client and the translator fakes
success for chown and chmod operations that only root could actually
do, reporting the faked IDs and modes in later stat calls, and allows
any user to open nodes regardless of permissions as is done for root.

## A trivial example

Let's demonstrate that chown and chgrp requires root permission.

    $ mkdir ~/etc
    $ touch ~/etc/this
    $ settrans ~/etc/this /hurd/hello
    $ ls -lha ~/etc/
      total 12K
	  drwxr-xr-x  2 joshua joshua 4.0K Oct 15 20:12 .
	  drwxr-xr-x 33 joshua joshua 4.0K Oct 15 20:11 ..
	  -r--r--r--  1 joshua joshua   14 Oct 15 20:12 this
	$
    $ chown root ~/etc/this
	  chown: changing ownership of '/home/joshua/etc/this': Operation not permitted

Now, let's run through `fakeroot-hurd`:

    $ fakeroot
    # ls -lha ~/etc/
      total 12K
	  drwxr-xr-x  2 root root 4.0K Oct 15 20:12 .
	  drwxr-xr-x 33 root root 4.0K Oct 15 20:11 ..
	  -r--r--r--  1 root root   14 Oct 15 20:12 this

The shell now believes we are root, and all the owner and group are turned into
root. Now we can chmod, chown, chgrp, ...

    # chown daemon ~/etc/this
    # ls -lha ~/etc/
      total 12K
	  drwxr-xr-x  2 root   root 4.0K Oct 15 20:12 .
	  drwxr-xr-x 33 root   root 4.0K Oct 15 20:11 ..
	  -r--r--r--  1 daemon root   14 Oct 15 20:12 this

## A manual example

We can also attach `/hurd/fakeroot` manually to `~/etc`, and we'll be able to
use `chown`, `chgrp`, `chmod`, etc. as a normal user.

    $ settrans ~/etc /hurd/fakeroot
    $ cd ~/etc
    $ cd
    $ showtrans ~/etc
	  /hurd/fakeroot
    $ ls -lha ~/etc/

	  total 16K
      drwxr-xr-x  2 joshua joshua 4.0K Oct 15 20:12 .
      drwxr-xr-x 33 root   root   4.0K Oct 15 20:11 ..
	  -r--r--r--  1 root   root     14 Oct 15 20:12 this

`fakeroot` turns all the owner and group to root when it starts.  Now
we can chmod, chown, and chgrp as a normal user.

    $ chown joshua ~/etc/this
    $ chgrp joshua ~/etc/this
    $ chmod +xr ~/etc/this
    $ ls -lha ~/etc/
	  total 16K
      drwxr-xr-x  2 joshua joshua 4.0K Oct 15 20:12 .
      drwxr-xr-x 33 root   root   4.0K Oct 15 20:11 ..
      -rwxr-xr-x  1 joshua joshua   14 Oct 15 20:12 this