Re: [RCF] [PATCH] unprivileged mount/umount

[Miklos Szeredi]

> r u sure, this program works?

Yes :)

> Sorry if I am saying something dumb here.
> Correct me.  When a file descriptor is sent from one process to other,
> arn't they referring to different files in each of the processes.
> fd=5 may be pointing to file 'xyz' in parent process, 
> where as fd=5 will be pointing to 'abc' in the child process.  

See 'man 7 unix' SCM_RIGHTS.

How do you know the program did not work?

Note: the program starts a new shell, it doesn't exit!  Do this in the
started shell (do not 'cd' before it):

  ls tmp/clonetest/mnt
  ls /tmp/clonetest/mnt

If you see different things, then the program worked.

It's not such a magic thing.  You can also do something similar for
example by:

shell1>  mount --bind / /tmp/mnt
shell1>  cd /tmp/mnt
sheel2>  umount -l /tmp/mnt

Now shell1 sees two separate "namespaces" in in CWD and /

Miklos
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