Re: [PATCH] private mounts

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Pavel Machek wrote:
> > > Actually, after you add right mount xyzzy /foo lines into .profile,
> > > you can just . ~/.profile ;-).
> > 
> > Is there a mount command that can do that?  We're talking about
> > private mounts - invisible to other namespaces, which includes the
> > other shells.
> > 
> > If there was a /proc/NNN/namespace, that would do the trick :)
> 
> Sounds like the solution, then. I do not think Al Viro is going to
> kill you for /proc/NNN/namespace...

Looking closer, I think we already have it.

It's called /proc/NNN/root.

Does chroot into /proc/NNN/root cause the chroot'ing process to adopt
the namespace of NNN?  Looking at the code, I think it does.

Furthermore, I think a daemon can acquire file descriptors for
multiple namespaces already, by open("/") and passing descriptors
between processes.  And the chroot can be done using /proc/self/fd/N
after receiving a descriptor.

This is because file descriptors, and current->fs->pwd and
current->fs->root, record the vfsmnt as well as the dentry that they
opened.

So no new system calls are needed.  A daemon to hand out per-user
namespaces (or any other policy) can be written using existing
kernels, and those namespaces can be joined using chroot.

That's the theory anyway.  It's always possible I misread the code (as
I don't use namespaces and don't have tools handy to try them).

-- Jamie
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]
  Powered by Linux