[Devel] Re: [RFC][PATCH 2/5] mqueue namespace: add unshare support

Daniel Hokka Zakrisson daniel at hozac.com
Thu Jul 10 15:58:32 PDT 2008


"Dave Hansen" <dave at linux.vnet.ibm.com>
>
>
> From: Cedric Le Goater <clg at fr.ibm.com>
>
> This patch includes the mqueue namespace in the nsproxy object. It
> also adds the support of unshare() and clone() with a new clone flag.
                                                        ^^^

> It's totally harmless for the moment because the current code still
> uses the default mqueue namespace object 'init_mq_ns'
>
> Changes since v6 Mar 05, 2008:
>
> 	* dropped new clone flag CLONE_NEWMQ and used CLONE_NEWIPC
> 	  instead

Maybe the description above should be updated too?

> Changes since v5 Feb 28, 2008:
>
> 	* fix typo in create_new_namespaces()
>
> Changes since v4:
>
> 	* remove CLONE_NEWNS enforcement. stalled user mounts are
> 	  handled in the fs ops.
>
> Signed-off-by: Cedric Le Goater <clg at fr.ibm.com>
> ---
>
>  linux-2.6.git-dave/include/linux/init_task.h    |    2 +
>  linux-2.6.git-dave/include/linux/mq_namespace.h |    1
>  linux-2.6.git-dave/include/linux/nsproxy.h      |    2 +
>  linux-2.6.git-dave/ipc/mq_namespace.c           |   36
> +++++++++++++++++++++++-
>  linux-2.6.git-dave/kernel/nsproxy.c             |   11 +++++++
>  5 files changed, 51 insertions(+), 1 deletion(-)
>
> diff -puN
> include/linux/init_task.h~mq_namespace-add-mq_namespace-to-nsproxy
> include/linux/init_task.h
> ---
> linux-2.6.git/include/linux/init_task.h~mq_namespace-add-mq_namespace-to-nsproxy	2008-06-24
> 12:03:17.000000000 -0700
> +++ linux-2.6.git-dave/include/linux/init_task.h	2008-06-24
> 12:03:17.000000000 -0700
> @@ -10,6 +10,7 @@
>  #include <linux/user_namespace.h>
>  #include <linux/securebits.h>
>  #include <net/net_namespace.h>
> +#include <linux/mq_namespace.h>
>
>  extern struct files_struct init_files;
>
> @@ -58,6 +59,7 @@ extern struct nsproxy init_nsproxy;
>  	INIT_NET_NS(net_ns)                                             \
>  	INIT_IPC_NS(ipc_ns)						\
>  	.user_ns	= &init_user_ns,				\
> +	INIT_MQ_NS(mq_ns)						\
>  }
>
>  #define INIT_SIGHAND(sighand) {						\
> diff -puN
> include/linux/mq_namespace.h~mq_namespace-add-mq_namespace-to-nsproxy
> include/linux/mq_namespace.h
> ---
> linux-2.6.git/include/linux/mq_namespace.h~mq_namespace-add-mq_namespace-to-nsproxy	2008-06-24
> 12:03:17.000000000 -0700
> +++ linux-2.6.git-dave/include/linux/mq_namespace.h	2008-06-24
> 12:03:17.000000000 -0700
> @@ -2,6 +2,7 @@
>  #define _LINUX_MQ_NAMESPACE_H
>
>  #include <linux/kref.h>
> +#include <linux/err.h>

Why is this necessary (in this patch)?

>  struct vfsmount;
>
> diff -puN include/linux/nsproxy.h~mq_namespace-add-mq_namespace-to-nsproxy
> include/linux/nsproxy.h
> ---
> linux-2.6.git/include/linux/nsproxy.h~mq_namespace-add-mq_namespace-to-nsproxy	2008-06-24
> 12:03:17.000000000 -0700
> +++ linux-2.6.git-dave/include/linux/nsproxy.h	2008-06-24
> 12:03:17.000000000 -0700
> @@ -8,6 +8,7 @@ struct mnt_namespace;
>  struct uts_namespace;
>  struct ipc_namespace;
>  struct pid_namespace;
> +struct mq_namespace;
>
>  /*
>   * A structure to contain pointers to all per-process
> @@ -29,6 +30,7 @@ struct nsproxy {
>  	struct pid_namespace *pid_ns;
>  	struct user_namespace *user_ns;
>  	struct net 	     *net_ns;
> +	struct mq_namespace *mq_ns;
>  };
>  extern struct nsproxy init_nsproxy;
>
> diff -puN ipc/mq_namespace.c~mq_namespace-add-mq_namespace-to-nsproxy
> ipc/mq_namespace.c
> ---
> linux-2.6.git/ipc/mq_namespace.c~mq_namespace-add-mq_namespace-to-nsproxy	2008-06-24
> 12:03:17.000000000 -0700
> +++ linux-2.6.git-dave/ipc/mq_namespace.c	2008-06-24 12:03:17.000000000
> -0700
> @@ -10,14 +10,48 @@
>   */
>
>  #include <linux/mq_namespace.h>
> +#include <linux/slab.h>
> +#include <linux/sched.h>
> +#include <linux/err.h>
> +
> +static struct mq_namespace *clone_mq_ns(struct mq_namespace *old_ns)
> +{
> +	struct mq_namespace *mq_ns;
> +
> +	mq_ns = kmalloc(sizeof(struct mq_namespace), GFP_KERNEL);
> +	if (!mq_ns)
> +		return ERR_PTR(-ENOMEM);
> +
> +	kref_init(&mq_ns->kref);
> +	mq_ns->queues_count	= 0;
> +	mq_ns->queues_max	= DFLT_QUEUESMAX;
> +	mq_ns->msg_max		= DFLT_MSGMAX;
> +	mq_ns->msgsize_max	= DFLT_MSGSIZEMAX;
> +	mq_ns->mnt		= NULL;
> +	return mq_ns;
> +}
>
>  struct mq_namespace *copy_mq_ns(unsigned long clone_flags,
>  				struct mq_namespace *old_ns)
>  {
> +	struct mq_namespace *mq_ns;
> +
>  	BUG_ON(!old_ns);
> -	return get_mq_ns(old_ns);
> +	get_mq_ns(old_ns);
> +
> +	if (!(clone_flags & CLONE_NEWIPC))
> +		return old_ns;
> +
> +	mq_ns = clone_mq_ns(old_ns);
> +
> +	put_mq_ns(old_ns);
> +	return mq_ns;
>  }
>
>  void free_mq_ns(struct kref *kref)
>  {
> +	struct mq_namespace *ns;
> +
> +	ns = container_of(kref, struct mq_namespace, kref);
> +	kfree(ns);
>  }
> diff -puN kernel/nsproxy.c~mq_namespace-add-mq_namespace-to-nsproxy
> kernel/nsproxy.c
> ---
> linux-2.6.git/kernel/nsproxy.c~mq_namespace-add-mq_namespace-to-nsproxy	2008-06-24
> 12:03:17.000000000 -0700
> +++ linux-2.6.git-dave/kernel/nsproxy.c	2008-06-24 12:03:17.000000000
> -0700
> @@ -93,8 +93,17 @@ static struct nsproxy *create_new_namesp
>  		goto out_net;
>  	}
>
> +	new_nsp->mq_ns = copy_mq_ns(flags, tsk->nsproxy->mq_ns);
> +	if (IS_ERR(new_nsp->mq_ns)) {
> +		err = PTR_ERR(new_nsp->mq_ns);
> +		goto out_mq;
> +	}
> +
>  	return new_nsp;
>
> +out_mq:
> +	if (new_nsp->net_ns)
> +		put_net(new_nsp->net_ns);
>  out_net:
>  	if (new_nsp->user_ns)
>  		put_user_ns(new_nsp->user_ns);
> @@ -182,6 +191,8 @@ void free_nsproxy(struct nsproxy *ns)
>  		put_pid_ns(ns->pid_ns);
>  	if (ns->user_ns)
>  		put_user_ns(ns->user_ns);
> +	if (ns->mq_ns)
> +		put_mq_ns(ns->mq_ns);
>  	put_net(ns->net_ns);
>  	kmem_cache_free(nsproxy_cachep, ns);
>  }
> _

-- 
Daniel Hokka Zakrisson
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