[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>

1 files changed, 18 insertions, 4 deletions

diff --git a/kernel/fork.c b/kernel/fork.c
index 208dd99f13bc..d6cc56558507 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);