From: Daniel Lezcano <daniel.lezcano@free•fr>
To: "Eric W. Biederman" <ebiederm@xmission•com>
Cc: hadi@cyberus•ca, Linux Netdev List <netdev@vger•kernel.org>,
containers@lists•linux-foundation.org,
Netfilter Development Mailinglist
<netfilter-devel@vger•kernel.org>,
Ben Greear <greearb@candelatech•com>,
Daniel Lezcano <dlezcano@fr•ibm.com>
Subject: Re: [RFC][PATCH] ns: Syscalls for better namespace sharing control.
Date: Thu, 25 Feb 2010 23:13:00 +0100 [thread overview]
Message-ID: <4B86F5EC.60902@free.fr> (raw)
In-Reply-To: <m1mxyx0yv7.fsf@fess.ebiederm.org>
Eric W. Biederman wrote:
> Daniel Lezcano <daniel.lezcano@free•fr> writes:
>
>
>> Eric W. Biederman wrote:
>>
>>> Introduce two new system calls:
>>> int nsfd(pid_t pid, unsigned long nstype);
>>> int setns(unsigned long nstype, int fd);
>>>
>>> These two new system calls address three specific problems that can
>>> make namespaces hard to work with.
>>> - Namespaces require a dedicated process to pin them in memory.
>>> - It is not possible to use a namespace unless you are the
>>> child of the original creator.
>>> - Namespaces don't have names that userspace can use to talk
>>> about them.
>>>
>>> The nsfd() system call returns a file descriptor that can
>>> be used to talk about a specific namespace, and to keep
>>> the specified namespace alive.
>>>
>>> The fd returned by nsfd() can be bind mounted as:
>>> mount --bind /proc/self/fd/N /some/filesystem/path
>>> to keep the namespace alive indefinitely as long as
>>> it is mounted.
>>>
>>> open works on the fd returned by nsfd() so another
>>> process can get a hold of it and do interesting things.
>>>
>>> Overall that allows for persistent naming of namespaces
>>> according to userspace policy.
>>>
>>> setns() allows changing the namespace of the current process
>>> to a namespace that originates with nsfd().
>>>
>>> Signed-off-by: Eric W. Biederman <ebiederm@xmission•com>
>>> ---
>>>
>>>
>> Is it planned to support all the namespaces for 'nsfd' ?
>> I mean will it be possible to specify an Or'ed combination of nstype to grab a
>> reference for several namespaces at a time of the targeted process ?
>>
>> for example : nsfd( 1234, NSTYPE_NET | NSTYPE_IPC, NSTYPE_MNT)
>>
>
> No, the plan is only one namespace at a time.
>
> It would not be much of a change to support multiple namespaces,
> but I don't think I want to go there. Bitmaps filling up are
> ugly and I don't see what would be gained.
>
The idea I had in mind when I asked this question was if we can "move" a
process inside a container, aka a set of namespaces :)
> I does make sense to support all of the namespaces we can support
> with unshare, but with nstype as an enumeration not as a bitmap.
>
I suppose when you say "to support all of the namespaces we can support
with *unshare*", you exclude the pid namespace which is created only
with clone, right ? Do you think we can extend the concept to all the
namespaces including the pid_namespace ?
> This is slightly better than the earlier version that used a netlink
> socket as the reference as I can give it the semantics of a deleted
> file and only when that file goes away drop the reference on the
> namespace. It is also better in that this interface can support all
> of the namespaces, without adding yet another syscall.
>
I like the idea :)
next prev parent reply other threads:[~2010-02-25 22:13 UTC|newest]
Thread overview: 94+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-01-14 14:05 RFC: netfilter: nf_conntrack: add support for "conntrack zones" Patrick McHardy
2010-01-14 15:05 ` jamal
2010-01-14 15:37 ` Patrick McHardy
2010-01-14 17:33 ` jamal
2010-01-15 10:15 ` Patrick McHardy
2010-01-15 15:19 ` jamal
2010-02-22 20:46 ` Eric W. Biederman
2010-02-22 21:55 ` jamal
2010-02-22 23:17 ` Eric W. Biederman
[not found] ` <m1wry46es9.fsf-+imSwln9KH6u2/kzUuoCbdi2O/JbrIOy@public.gmane.org>
2010-02-23 13:27 ` jamal
2010-02-23 14:07 ` Eric W. Biederman
2010-02-23 14:20 ` jamal
2010-02-23 20:00 ` Eric W. Biederman
2010-02-23 23:09 ` jamal
2010-02-24 1:43 ` Eric W. Biederman
2010-02-25 20:57 ` [RFC][PATCH] ns: Syscalls for better namespace sharing control Eric W. Biederman
2010-02-25 21:31 ` Daniel Lezcano
2010-02-25 21:49 ` Eric W. Biederman
2010-02-25 22:13 ` Daniel Lezcano [this message]
2010-02-25 22:31 ` Eric W. Biederman
2010-02-26 20:35 ` Eric W. Biederman
2010-02-25 21:46 ` Matt Helsley
2010-02-25 21:54 ` Eric W. Biederman
2010-02-26 0:53 ` Eric W. Biederman
2010-02-26 1:09 ` Matt Helsley
2010-02-26 1:26 ` Eric W. Biederman
2010-02-26 3:15 ` [RFC][PATCH] ns: Syscalls for better namespace sharing control. v2 Eric W. Biederman
[not found] ` <m18wagy9f3.fsf_-_-+imSwln9KH6u2/kzUuoCbdi2O/JbrIOy@public.gmane.org>
2010-03-03 20:29 ` Jonathan Corbet
2010-03-03 20:50 ` Eric W. Biederman
[not found] ` <m1pr3t2fvl.fsf_-_-+imSwln9KH6u2/kzUuoCbdi2O/JbrIOy@public.gmane.org>
2010-02-26 21:13 ` [RFC][PATCH] ns: Syscalls for better namespace sharing control Pavel Emelyanov
2010-02-26 21:24 ` Eric W. Biederman
2010-02-26 21:34 ` Pavel Emelyanov
2010-02-26 21:42 ` Eric W. Biederman
2010-02-26 21:58 ` Oren Laadan
2010-02-26 22:16 ` Eric W. Biederman
2010-02-26 22:52 ` Oren Laadan
2010-02-26 23:13 ` Eric W. Biederman
2010-02-27 8:30 ` Pavel Emelyanov
2010-02-27 9:04 ` Eric W. Biederman
[not found] ` <m1mxyvrqvk.fsf-+imSwln9KH6u2/kzUuoCbdi2O/JbrIOy@public.gmane.org>
2010-02-27 9:21 ` Pavel Emelyanov
2010-02-27 9:42 ` Eric W. Biederman
2010-02-27 16:16 ` Pavel Emelyanov
2010-02-27 19:08 ` Eric W. Biederman
2010-02-27 19:29 ` Pavel Emelyanov
2010-02-27 19:44 ` Eric W. Biederman
2010-02-28 22:05 ` Daniel Lezcano
2010-03-01 19:24 ` Eric W. Biederman
2010-03-01 21:42 ` Eric W. Biederman
2010-03-02 13:10 ` Cedric Le Goater
2010-03-02 15:03 ` Pavel Emelyanov
2010-03-02 15:14 ` Jan Engelhardt
2010-03-02 21:45 ` Eric W. Biederman
2010-03-02 21:19 ` Sukadev Bhattiprolu
2010-03-02 22:13 ` Eric W. Biederman
2010-03-03 0:07 ` Sukadev Bhattiprolu
2010-03-03 0:46 ` Eric W. Biederman
2010-03-03 15:38 ` Serge E. Hallyn
2010-03-03 19:47 ` Eric W. Biederman
2010-03-04 21:45 ` Eric W. Biederman
2010-03-04 22:55 ` Jan Engelhardt
2010-03-03 16:50 ` Pavel Emelyanov
2010-03-03 20:16 ` Eric W. Biederman
2010-03-05 19:18 ` Pavel Emelyanov
2010-03-05 20:26 ` Eric W. Biederman
2010-03-06 14:47 ` Daniel Lezcano
[not found] ` <4B926B1B.5070207-GANU6spQydw@public.gmane.org>
2010-03-06 20:48 ` Eric W. Biederman
[not found] ` <m1aaulyy5c.fsf-+imSwln9KH6u2/kzUuoCbdi2O/JbrIOy@public.gmane.org>
2010-03-06 21:26 ` Daniel Lezcano
2010-03-08 8:32 ` Eric W. Biederman
2010-03-08 16:54 ` Daniel Lezcano
2010-03-08 17:29 ` Eric W. Biederman
2010-03-08 19:57 ` Daniel Lezcano
2010-03-08 20:24 ` Eric W. Biederman
2010-03-08 20:42 ` Daniel Lezcano
2010-03-08 20:47 ` Eric W. Biederman
2010-03-08 21:12 ` Daniel Lezcano
2010-03-08 21:25 ` Eric W. Biederman
2010-03-08 21:49 ` Serge E. Hallyn
2010-03-08 22:24 ` Eric W. Biederman
2010-03-09 10:03 ` Daniel Lezcano
2010-03-09 10:13 ` Eric W. Biederman
2010-03-09 10:26 ` Daniel Lezcano
2010-03-10 21:16 ` Daniel Lezcano
2010-03-08 17:07 ` Serge E. Hallyn
2010-03-08 17:35 ` Eric W. Biederman
2010-03-08 17:47 ` Serge E. Hallyn
2010-03-03 20:59 ` Oren Laadan
2010-03-03 21:05 ` Eric W. Biederman
[not found] ` <m1bpfbwuze.fsf-+imSwln9KH6u2/kzUuoCbdi2O/JbrIOy@public.gmane.org>
2010-02-26 21:35 ` Pavel Emelyanov
2010-02-26 21:49 ` Eric W. Biederman
2010-02-23 23:49 ` RFC: netfilter: nf_conntrack: add support for "conntrack zones" Matt Helsley
2010-02-24 1:32 ` Eric W. Biederman
2010-02-24 1:39 ` Serge E. Hallyn
2010-01-14 18:32 ` Ben Greear
2010-01-15 15:03 ` jamal
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