[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>

2 files changed, 46 insertions, 17 deletions

diff --git a/kernel/fork.c b/kernel/fork.c
index 208dd99f13b..d6cc5655850 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1608,13 +1608,15 @@ asmlinkage long sys_unshare(unsigned long unshare_flags)
 	struct sem_undo_list *new_ulist = NULL;
 	struct nsproxy *new_nsproxy = NULL, *old_nsproxy = NULL;
 	struct uts_namespace *uts, *new_uts = NULL;
+	struct ipc_namespace *ipc, *new_ipc = NULL;
 
 	check_unshare_flags(&unshare_flags);
 
 	/* Return -EINVAL for all unsupported flags */
 	err = -EINVAL;
 	if (unshare_flags & ~(CLONE_THREAD|CLONE_FS|CLONE_NEWNS|CLONE_SIGHAND|
-				CLONE_VM|CLONE_FILES|CLONE_SYSVSEM|CLONE_NEWUTS))
+				CLONE_VM|CLONE_FILES|CLONE_SYSVSEM|
+				CLONE_NEWUTS|CLONE_NEWIPC))
 		goto bad_unshare_out;
 
 	if ((err = unshare_thread(unshare_flags)))
@@ -1633,18 +1635,20 @@ asmlinkage long sys_unshare(unsigned long unshare_flags)
 		goto bad_unshare_cleanup_fd;
 	if ((err = unshare_utsname(unshare_flags, &new_uts)))
 		goto bad_unshare_cleanup_semundo;
+	if ((err = unshare_ipcs(unshare_flags, &new_ipc)))
+		goto bad_unshare_cleanup_uts;
 
-	if (new_ns || new_uts) {
+	if (new_ns || new_uts || new_ipc) {
 		old_nsproxy = current->nsproxy;
 		new_nsproxy = dup_namespaces(old_nsproxy);
 		if (!new_nsproxy) {
 			err = -ENOMEM;
-			goto bad_unshare_cleanup_uts;
+			goto bad_unshare_cleanup_ipc;
 		}
 	}
 
 	if (new_fs || new_ns || new_sigh || new_mm || new_fd || new_ulist ||
-				new_uts) {
+				new_uts || new_ipc) {
 
 		task_lock(current);
 
@@ -1692,12 +1696,22 @@ asmlinkage long sys_unshare(unsigned long unshare_flags)
 			new_uts = uts;
 		}
 
+		if (new_ipc) {
+			ipc = current->nsproxy->ipc_ns;
+			current->nsproxy->ipc_ns = new_ipc;
+			new_ipc = ipc;
+		}
+
 		task_unlock(current);
 	}
 
 	if (new_nsproxy)
 		put_nsproxy(new_nsproxy);
 
+bad_unshare_cleanup_ipc:
+	if (new_ipc)
+		put_ipc_ns(new_ipc);
+
 bad_unshare_cleanup_uts:
 	if (new_uts)
 		put_uts_ns(new_uts);
diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
index 8246813335c..8d6c852dc51 100644
--- a/kernel/nsproxy.c
+++ b/kernel/nsproxy.c
@@ -7,6 +7,10 @@
  *  modify it under the terms of the GNU General Public License as
  *  published by the Free Software Foundation, version 2 of the
  *  License.
+ *
+ *  Jun 2006 - namespaces support
+ *             OpenVZ, SWsoft Inc.
+ *             Pavel Emelianov <xemul@openvz.org>
  */
 
 #include <linux/module.h>
@@ -62,6 +66,8 @@ struct nsproxy *dup_namespaces(struct nsproxy *orig)
 			get_namespace(ns->namespace);
 		if (ns->uts_ns)
 			get_uts_ns(ns->uts_ns);
+		if (ns->ipc_ns)
+			get_ipc_ns(ns->ipc_ns);
 	}
 
 	return ns;
@@ -82,7 +88,7 @@ int copy_namespaces(int flags, struct task_struct *tsk)
 
 	get_nsproxy(old_ns);
 
-	if (!(flags & (CLONE_NEWNS | CLONE_NEWUTS)))
+	if (!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC)))
 		return 0;
 
 	new_ns = clone_namespaces(old_ns);
@@ -94,24 +100,31 @@ int copy_namespaces(int flags, struct task_struct *tsk)
 	tsk->nsproxy = new_ns;
 
 	err = copy_namespace(flags, tsk);
-	if (err) {
-		tsk->nsproxy = old_ns;
-		put_nsproxy(new_ns);
-		goto out;
-	}
+	if (err)
+		goto out_ns;
 
 	err = copy_utsname(flags, tsk);
-	if (err) {
-		if (new_ns->namespace)
-			put_namespace(new_ns->namespace);
-		tsk->nsproxy = old_ns;
-		put_nsproxy(new_ns);
-		goto out;
-	}
+	if (err)
+		goto out_uts;
+
+	err = copy_ipcs(flags, tsk);
+	if (err)
+		goto out_ipc;
 
 out:
 	put_nsproxy(old_ns);
 	return err;
+
+out_ipc:
+	if (new_ns->uts_ns)
+		put_uts_ns(new_ns->uts_ns);
+out_uts:
+	if (new_ns->namespace)
+		put_namespace(new_ns->namespace);
+out_ns:
+	tsk->nsproxy = old_ns;
+	put_nsproxy(new_ns);
+	goto out;
 }
 
 void free_nsproxy(struct nsproxy *ns)
@@ -120,5 +133,7 @@ void free_nsproxy(struct nsproxy *ns)
 			put_namespace(ns->namespace);
 		if (ns->uts_ns)
 			put_uts_ns(ns->uts_ns);
+		if (ns->ipc_ns)
+			put_ipc_ns(ns->ipc_ns);
 		kfree(ns);
 }