IPC: introduce ipc_update_perm()

The IPC_SET command performs the same permission setting for all IPCs.  This
patch introduces a common ipc_update_perm() function to update these
permissions and makes use of it for all IPCs.

Signed-off-by: Pierre Peiffer <pierre.peiffer@bull.net>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: Nadia Derbey <Nadia.Derbey@bull.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/ipc/util.c b/ipc/util.c
index 7a5d5e3..dc8943a 100644
--- a/ipc/util.c
+++ b/ipc/util.c
@@ -811,6 +811,19 @@
 		return ipcget_public(ns, ids, ops, params);
 }
 
+/**
+ * ipc_update_perm - update the permissions of an IPC.
+ * @in:  the permission given as input.
+ * @out: the permission of the ipc to set.
+ */
+void ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out)
+{
+	out->uid = in->uid;
+	out->gid = in->gid;
+	out->mode = (out->mode & ~S_IRWXUGO)
+		| (in->mode & S_IRWXUGO);
+}
+
 #ifdef __ARCH_WANT_IPC_PARSE_VERSION