Messages in this thread | | | Date | Tue, 26 Apr 2005 15:07:15 +0100 | From | Jamie Lokier <> | Subject | Re: [PATCH] private mounts |
| |
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 majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |