Re: [PATCH 3/5] Move the IPC namespace under the option

[Cedric Le Goater <clg@fr.ibm.com>]

Pavel Emelyanov wrote:
> Currently all the IPC namespace management code is in 
> ipc/util.c. I moved this code into ipc/namespace.c file
> which is compiled out when needed.
> 
> The linux/ipc_namespace.h file is used to store the
> prototypes of the functions in namespace.c and the stubs
> for NAMESPACES=n case. This is done so, because the stub
> for copy_ipc_namespace requires the knoweledge of the
> CLONE_NEWIPC flag, which is in sched.h. But the linux/ipc.h
> file itself in included into many many .c files via the
> sys.h->sem.h sequence so adding the sched.h into it will
> make all these .c depend on sched.h which is not that good.
> On the other hand the knowledge about the namespaces stuff 
> is required in 4 .c files only.
> 
> Besides, this patch compiles out some auxiliary functions
> from ipc/sem.c, msg.c and shm.c files.
> 
> Signied-off-by: Pavel Emelyanov <xemul@openvz.org>
      ^
that sounds french :)


Also, for the code aesthetic, 

I think that ipc/ipc_namespace.c is a better name which fits
the header file ipc/ipc_namespace.h.

I'm wondering if it possible to move the init routines :

	#ifdef CONFIG_NAMESPACES
	int {msg,sem,shm}_init_ns(struct ipc_namespace *ns)
	{
		...
	}
	#endif

from the ipc/{msg,sem,shm}.c file to the ipc/ipc_namespace.c file.
It would look better in the code than using ugly #ifdef.

Thanks !

C.

> 
> ---
> 
> diff --git a/include/linux/ipc.h b/include/linux/ipc.h
> index 96988d1..b882610 100644
> --- a/include/linux/ipc.h
> +++ b/include/linux/ipc.h
> @@ -100,56 +100,6 @@ struct kern_ipc_perm
>  	void		*security;
>  };
> 
> -struct ipc_ids;
> -struct ipc_namespace {
> -	struct kref	kref;
> -	struct ipc_ids	*ids[3];
> -
> -	int		sem_ctls[4];
> -	int		used_sems;
> -
> -	int		msg_ctlmax;
> -	int		msg_ctlmnb;
> -	int		msg_ctlmni;
> -
> -	size_t		shm_ctlmax;
> -	size_t		shm_ctlall;
> -	int		shm_ctlmni;
> -	int		shm_tot;
> -};
> -
> -extern struct ipc_namespace init_ipc_ns;
> -
> -#ifdef CONFIG_SYSVIPC
> -#define INIT_IPC_NS(ns)		.ns		= &init_ipc_ns,
> -extern void free_ipc_ns(struct kref *kref);
> -extern struct ipc_namespace *copy_ipcs(unsigned long flags,
> -						struct ipc_namespace *ns);
> -#else
> -#define INIT_IPC_NS(ns)
> -static inline struct ipc_namespace *copy_ipcs(unsigned long flags,
> -						struct ipc_namespace *ns)
> -{
> -	return ns;
> -}
> -#endif
> -
> -static inline struct ipc_namespace *get_ipc_ns(struct ipc_namespace *ns)
> -{
> -#ifdef CONFIG_SYSVIPC
> -	if (ns)
> -		kref_get(&ns->kref);
> -#endif
> -	return ns;
> -}
> -
> -static inline void put_ipc_ns(struct ipc_namespace *ns)
> -{
> -#ifdef CONFIG_SYSVIPC
> -	kref_put(&ns->kref, free_ipc_ns);
> -#endif
> -}
> -
>  #endif /* __KERNEL__ */
> 
>  #endif /* _LINUX_IPC_H */
> diff --git a/include/linux/ipc_namespace.h b/include/linux/ipc_namespace.h
> new file mode 100644
> index 0000000..3d8a516
> --- /dev/null
> +++ b/include/linux/ipc_namespace.h
> @@ -0,0 +1,67 @@
> +#ifndef __IPC_NAMESPACE_H__
> +#define __IPC_NAMESPACE_H__
> +
> +#include <linux/err.h>
> +
> +struct ipc_ids;
> +struct ipc_namespace {
> +	struct kref	kref;
> +	struct ipc_ids	*ids[3];
> +
> +	int		sem_ctls[4];
> +	int		used_sems;
> +
> +	int		msg_ctlmax;
> +	int		msg_ctlmnb;
> +	int		msg_ctlmni;
> +
> +	size_t		shm_ctlmax;
> +	size_t		shm_ctlall;
> +	int		shm_ctlmni;
> +	int		shm_tot;
> +};
> +
> +extern struct ipc_namespace init_ipc_ns;
> +
> +#ifdef CONFIG_SYSVIPC
> +#define INIT_IPC_NS(ns)		.ns		= &init_ipc_ns,
> +#else
> +#define INIT_IPC_NS(ns)
> +#endif
> +
> +#if defined(CONFIG_SYSVIPC) && defined(CONFIG_NAMESPACES)
> +extern void free_ipc_ns(struct kref *kref);
> +extern struct ipc_namespace *copy_ipcs(unsigned long flags,
> +						struct ipc_namespace *ns);
> +
> +static inline struct ipc_namespace *get_ipc_ns(struct ipc_namespace *ns)
> +{
> +	if (ns)
> +		kref_get(&ns->kref);
> +	return ns;
> +}
> +
> +static inline void put_ipc_ns(struct ipc_namespace *ns)
> +{
> +	kref_put(&ns->kref, free_ipc_ns);
> +}
> +#else
> +static inline struct ipc_namespace *copy_ipcs(unsigned long flags,
> +		struct ipc_namespace *ns)
> +{
> +	if (flags & CLONE_NEWIPC)
> +		return ERR_PTR(-EINVAL);
> +
> +	return ns;
> +}
> +
> +static inline struct ipc_namespace *get_ipc_ns(struct ipc_namespace *ns)
> +{
> +	return ns;
> +}
> +
> +static inline void put_ipc_ns(struct ipc_namespace *ns)
> +{
> +}
> +#endif
> +#endif
> diff --git a/ipc/util.c b/ipc/util.c
> index fd29246..44fb843 100644
> --- a/ipc/util.c
> +++ b/ipc/util.c
> @@ -32,6 +32,7 @@
>  #include <linux/proc_fs.h>
>  #include <linux/audit.h>
>  #include <linux/nsproxy.h>
> +#include <linux/ipc_namespace.h>
> 
>  #include <asm/unistd.h>
> 
> @@ -50,66 +51,6 @@ struct ipc_namespace init_ipc_ns = {
>  	},
>  };
> 
> -static struct ipc_namespace *clone_ipc_ns(struct ipc_namespace *old_ns)
> -{
> -	int err;
> -	struct ipc_namespace *ns;
> -
> -	err = -ENOMEM;
> -	ns = kmalloc(sizeof(struct ipc_namespace), GFP_KERNEL);
> -	if (ns == NULL)
> -		goto err_mem;
> -
> -	err = sem_init_ns(ns);
> -	if (err)
> -		goto err_sem;
> -	err = msg_init_ns(ns);
> -	if (err)
> -		goto err_msg;
> -	err = shm_init_ns(ns);
> -	if (err)
> -		goto err_shm;
> -
> -	kref_init(&ns->kref);
> -	return ns;
> -
> -err_shm:
> -	msg_exit_ns(ns);
> -err_msg:
> -	sem_exit_ns(ns);
> -err_sem:
> -	kfree(ns);
> -err_mem:
> -	return ERR_PTR(err);
> -}
> -
> -struct ipc_namespace *copy_ipcs(unsigned long flags, struct ipc_namespace *ns)
> -{
> -	struct ipc_namespace *new_ns;
> -
> -	BUG_ON(!ns);
> -	get_ipc_ns(ns);
> -
> -	if (!(flags & CLONE_NEWIPC))
> -		return ns;
> -
> -	new_ns = clone_ipc_ns(ns);
> -
> -	put_ipc_ns(ns);
> -	return new_ns;
> -}
> -
> -void free_ipc_ns(struct kref *kref)
> -{
> -	struct ipc_namespace *ns;
> -
> -	ns = container_of(kref, struct ipc_namespace, kref);
> -	sem_exit_ns(ns);
> -	msg_exit_ns(ns);
> -	shm_exit_ns(ns);
> -	kfree(ns);
> -}
> -
>  /**
>   *	ipc_init	-	initialise IPC subsystem
>   *
> diff --git a/ipc/namespace.c b/ipc/namespace.c
> new file mode 100644
> index 0000000..cef1139
> --- /dev/null
> +++ b/ipc/namespace.c
> @@ -0,0 +1,73 @@
> +/*
> + * linux/ipc/namespace.c
> + * Copyright (C) 2006 Pavel Emelyanov <xemul@openvz.org> OpenVZ, SWsoft Inc.
> + */
> +
> +#include <linux/ipc.h>
> +#include <linux/msg.h>
> +#include <linux/ipc_namespace.h>
> +#include <linux/rcupdate.h>
> +#include <linux/nsproxy.h>
> +#include <linux/slab.h>
> +
> +#include "util.h"
> +
> +static struct ipc_namespace *clone_ipc_ns(struct ipc_namespace *old_ns)
> +{
> +	int err;
> +	struct ipc_namespace *ns;
> +
> +	err = -ENOMEM;
> +	ns = kmalloc(sizeof(struct ipc_namespace), GFP_KERNEL);
> +	if (ns == NULL)
> +		goto err_mem;
> +
> +	err = sem_init_ns(ns);
> +	if (err)
> +		goto err_sem;
> +	err = msg_init_ns(ns);
> +	if (err)
> +		goto err_msg;
> +	err = shm_init_ns(ns);
> +	if (err)
> +		goto err_shm;
> +
> +	kref_init(&ns->kref);
> +	return ns;
> +
> +err_shm:
> +	msg_exit_ns(ns);
> +err_msg:
> +	sem_exit_ns(ns);
> +err_sem:
> +	kfree(ns);
> +err_mem:
> +	return ERR_PTR(err);
> +}
> +
> +struct ipc_namespace *copy_ipcs(unsigned long flags, struct ipc_namespace *ns)
> +{
> +	struct ipc_namespace *new_ns;
> +
> +	BUG_ON(!ns);
> +	get_ipc_ns(ns);
> +
> +	if (!(flags & CLONE_NEWIPC))
> +		return ns;
> +
> +	new_ns = clone_ipc_ns(ns);
> +
> +	put_ipc_ns(ns);
> +	return new_ns;
> +}
> +
> +void free_ipc_ns(struct kref *kref)
> +{
> +	struct ipc_namespace *ns;
> +
> +	ns = container_of(kref, struct ipc_namespace, kref);
> +	sem_exit_ns(ns);
> +	msg_exit_ns(ns);
> +	shm_exit_ns(ns);
> +	kfree(ns);
> +}
> diff --git a/ipc/Makefile b/ipc/Makefile
> index b93bba6..d81fb35 100644
> --- a/ipc/Makefile
> +++ b/ipc/Makefile
> @@ -7,4 +7,5 @@ obj-$(CONFIG_SYSVIPC) += util.o msgutil.
>  obj-$(CONFIG_SYSVIPC_SYSCTL) += ipc_sysctl.o
>  obj_mq-$(CONFIG_COMPAT) += compat_mq.o
>  obj-$(CONFIG_POSIX_MQUEUE) += mqueue.o msgutil.o $(obj_mq-y)
> +obj-$(CONFIG_NAMESPACES) += namespace.o
> 
> diff --git a/ipc/ipc_sysctl.c b/ipc/ipc_sysctl.c
> index 79e24e8..7f4235b 100644
> --- a/ipc/ipc_sysctl.c
> +++ b/ipc/ipc_sysctl.c
> @@ -14,6 +14,7 @@
>  #include <linux/nsproxy.h>
>  #include <linux/sysctl.h>
>  #include <linux/uaccess.h>
> +#include <linux/ipc_namespace.h>
> 
>  static void *get_ipc(ctl_table *table)
>  {
> diff --git a/ipc/msg.c b/ipc/msg.c
> index b7274db..eb74965 100644
> --- a/ipc/msg.c
> +++ b/ipc/msg.c
> @@ -36,6 +36,7 @@
>  #include <linux/seq_file.h>
>  #include <linux/mutex.h>
>  #include <linux/nsproxy.h>
> +#include <linux/ipc_namespace.h>
> 
>  #include <asm/current.h>
>  #include <asm/uaccess.h>
> @@ -92,6 +93,7 @@ static void __msg_init_ns(struct ipc_nam
>  	ipc_init_ids(ids);
>  }
> 
> +#ifdef CONFIG_NAMESPACES
>  int msg_init_ns(struct ipc_namespace *ns)
>  {
>  	struct ipc_ids *ids;
> @@ -127,6 +129,7 @@ void msg_exit_ns(struct ipc_namespace *n
>  	kfree(ns->ids[IPC_MSG_IDS]);
>  	ns->ids[IPC_MSG_IDS] = NULL;
>  }
> +#endif
> 
>  void __init msg_init(void)
>  {
> diff --git a/ipc/sem.c b/ipc/sem.c
> index 45c7e57..2e9f449 100644
> --- a/ipc/sem.c
> +++ b/ipc/sem.c
> @@ -82,6 +82,7 @@
>  #include <linux/seq_file.h>
>  #include <linux/mutex.h>
>  #include <linux/nsproxy.h>
> +#include <linux/ipc_namespace.h>
> 
>  #include <asm/uaccess.h>
>  #include "util.h"
> @@ -130,6 +131,7 @@ static void __sem_init_ns(struct ipc_nam
>  	ipc_init_ids(ids);
>  }
> 
> +#ifdef CONFIG_NAMESPACES
>  int sem_init_ns(struct ipc_namespace *ns)
>  {
>  	struct ipc_ids *ids;
> @@ -165,6 +167,7 @@ void sem_exit_ns(struct ipc_namespace *n
>  	kfree(ns->ids[IPC_SEM_IDS]);
>  	ns->ids[IPC_SEM_IDS] = NULL;
>  }
> +#endif
> 
>  void __init sem_init (void)
>  {
> diff --git a/ipc/shm.c b/ipc/shm.c
> index f28f2a3..2717cbc 100644
> --- a/ipc/shm.c
> +++ b/ipc/shm.c
> @@ -38,6 +38,7 @@
>  #include <linux/mutex.h>
>  #include <linux/nsproxy.h>
>  #include <linux/mount.h>
> +#include <linux/ipc_namespace.h>
> 
>  #include <asm/uaccess.h>
> 
> @@ -97,6 +98,7 @@ static void do_shm_rmid(struct ipc_names
>  		shm_destroy(ns, shp);
>  }
> 
> +#ifdef CONFIG_NAMESPACES
>  int shm_init_ns(struct ipc_namespace *ns)
>  {
>  	struct ipc_ids *ids;
> @@ -132,6 +134,7 @@ void shm_exit_ns(struct ipc_namespace *n
>  	kfree(ns->ids[IPC_SHM_IDS]);
>  	ns->ids[IPC_SHM_IDS] = NULL;
>  }
> +#endif
> 
>  void __init shm_init (void)
>  {
> diff --git a/ipc/util.h b/ipc/util.h
> index 99414a3..8972402 100644
> --- a/ipc/util.h
> +++ b/ipc/util.h
> @@ -20,6 +20,8 @@ void sem_init (void);
>  void msg_init (void);
>  void shm_init (void);
> 
> +struct ipc_namespace;
> +
>  int sem_init_ns(struct ipc_namespace *ns);
>  int msg_init_ns(struct ipc_namespace *ns);
>  int shm_init_ns(struct ipc_namespace *ns);
> diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
> index ee68964..5a27426 100644
> --- a/kernel/nsproxy.c
> +++ b/kernel/nsproxy.c
> @@ -20,6 +20,7 @@
>  #include <linux/mnt_namespace.h>
>  #include <linux/utsname.h>
>  #include <linux/pid_namespace.h>
> +#include <linux/ipc_namespace.h>
> 
>  static struct kmem_cache *nsproxy_cachep;
> 
> 
> 

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