[PATCH] IPC namespace core

This patch set allows to unshare IPCs and have a private set of IPC objects
(sem, shm, msg) inside namespace.  Basically, it is another building block of
containers functionality.

This patch implements core IPC namespace changes:
- ipc_namespace structure
- new config option CONFIG_IPC_NS
- adds CLONE_NEWIPC flag
- unshare support

[clg@fr.ibm.com: small fix for unshare of ipc namespace]
[akpm@osdl.org: build fix]
Signed-off-by: Pavel Emelianov <xemul@openvz.org>
Signed-off-by: Kirill Korotaev <dev@openvz.org>
Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

4 files changed, 40 insertions, 0 deletions

diff --git a/include/linux/init_task.h b/include/linux/init_task.h
index e08531ec32f..ceecf69dfa3 100644
--- a/include/linux/init_task.h
+++ b/include/linux/init_task.h
@@ -74,6 +74,7 @@ extern struct nsproxy init_nsproxy;
 	.count		= ATOMIC_INIT(1),				\
 	.nslock		= SPIN_LOCK_UNLOCKED,				\
 	.uts_ns		= &init_uts_ns,					\
+	.ipc_ns		= &init_ipc_ns,					\
 	.namespace	= NULL,						\
 }
 
diff --git a/include/linux/ipc.h b/include/linux/ipc.h
index b291189737e..36027b10f28 100644
--- a/include/linux/ipc.h
+++ b/include/linux/ipc.h
@@ -2,6 +2,7 @@
 #define _LINUX_IPC_H
 
 #include <linux/types.h>
+#include <linux/kref.h>
 
 #define IPC_PRIVATE ((__kernel_key_t) 0)  
 
@@ -68,6 +69,41 @@ 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;
+extern void free_ipc_ns(struct kref *kref);
+extern int copy_ipcs(unsigned long flags, struct task_struct *tsk);
+extern int unshare_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);
+}
+
 #endif /* __KERNEL__ */
 
 #endif /* _LINUX_IPC_H */
diff --git a/include/linux/nsproxy.h b/include/linux/nsproxy.h
index 9c2e0ad508d..f6baecdeecd 100644
--- a/include/linux/nsproxy.h
+++ b/include/linux/nsproxy.h
@@ -6,6 +6,7 @@
 
 struct namespace;
 struct uts_namespace;
+struct ipc_namespace;
 
 /*
  * A structure to contain pointers to all per-process
@@ -23,6 +24,7 @@ struct nsproxy {
 	atomic_t count;
 	spinlock_t nslock;
 	struct uts_namespace *uts_ns;
+	struct ipc_namespace *ipc_ns;
 	struct namespace *namespace;
 };
 extern struct nsproxy init_nsproxy;
diff --git a/include/linux/sched.h b/include/linux/sched.h
index a973e701231..9ba959e3426 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -25,6 +25,7 @@
 #define CLONE_CHILD_SETTID	0x01000000	/* set the TID in the child */
 #define CLONE_STOPPED		0x02000000	/* Start in stopped state */
 #define CLONE_NEWUTS		0x04000000	/* New utsname group? */
+#define CLONE_NEWIPC		0x08000000	/* New ipcs */
 
 /*
  * Scheduling policies