Re: [PATCH] private mounts

From: Jan Hudec
Date: Tue Apr 26 2005 - 04:08:44 EST


On Mon, Apr 25, 2005 at 17:17:35 +0200, Bodo Eggert <harvested.in.lkml@xxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
> Jan Hudec <bulb@xxxxxx> wrote:
> > On Mon, Apr 25, 2005 at 11:58:50 +0200, Miklos Szeredi wrote:
> Use a daemon to keep an additional reference to the namespace? That's UGLY.

It's as ugly as ssh-agent.

But I have to say, that I really like attachable namespaces bettern than
descriptor mount bind. It's a hell lot simpler to work with.

> With attachable namespaces, the whole thing should be as simple as
> (pseudocode)
> mknamespace -p users/$UID # (like mkdir -p)
> setnamespace users/$UID # (like cd)

Well, yes and no. We should probably just have a syscall
int join_namespace(pid_t pid)
which would join the namespace process pid uses. And then have a PAM
session module, that would attach the namespace of the first user's
session (creating new namespace if this is the first session).

> Optionally, the namespaces and their private mounts might be scheduled to
> be removed if the last user is gone, or they need to be persistent,
> depending on the applicaton (e.g. ssh used as rexec or shared mounts).

I'd have them garbage-collected. When last process using them goes away,
so does the namespace. If that's not what you want, start a persistent
process for the user.

-------------------------------------------------------------------------------
Jan 'Bulb' Hudec <bulb@xxxxxx>

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