1 files changed, 139 insertions, 0 deletions
diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
new file mode 100644
index 00000000000000..6ebdb82a0ce43a
--- /dev/null
+++ b/kernel/nsproxy.c
@@ -0,0 +1,139 @@
+/*
+ *  Copyright (C) 2006 IBM Corporation
+ *
+ *  Author: Serge Hallyn <serue@us.ibm.com>
+ *
+ *  This program is free software; you can redistribute it and/or
+ *  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>
+#include <linux/version.h>
+#include <linux/nsproxy.h>
+#include <linux/init_task.h>
+#include <linux/namespace.h>
+#include <linux/utsname.h>
+
+struct nsproxy init_nsproxy = INIT_NSPROXY(init_nsproxy);
+
+static inline void get_nsproxy(struct nsproxy *ns)
+{
+	atomic_inc(&ns->count);
+}
+
+void get_task_namespaces(struct task_struct *tsk)
+{
+	struct nsproxy *ns = tsk->nsproxy;
+	if (ns) {
+		get_nsproxy(ns);
+	}
+}
+
+/*
+ * creates a copy of "orig" with refcount 1.
+ * This does not grab references to the contained namespaces,
+ * so that needs to be done by dup_namespaces.
+ */
+static inline struct nsproxy *clone_namespaces(struct nsproxy *orig)
+{
+	struct nsproxy *ns;
+
+	ns = kmalloc(sizeof(struct nsproxy), GFP_KERNEL);
+	if (ns) {
+		memcpy(ns, orig, sizeof(struct nsproxy));
+		atomic_set(&ns->count, 1);
+	}
+	return ns;
+}
+
+/*
+ * copies the nsproxy, setting refcount to 1, and grabbing a
+ * reference to all contained namespaces.  Called from
+ * sys_unshare()
+ */
+struct nsproxy *dup_namespaces(struct nsproxy *orig)
+{
+	struct nsproxy *ns = clone_namespaces(orig);
+
+	if (ns) {
+		if (ns->namespace)
+			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;
+}
+
+/*
+ * called from clone.  This now handles copy for nsproxy and all
+ * namespaces therein.
+ */
+int copy_namespaces(int flags, struct task_struct *tsk)
+{
+	struct nsproxy *old_ns = tsk->nsproxy;
+	struct nsproxy *new_ns;
+	int err = 0;
+
+	if (!old_ns)
+		return 0;
+
+	get_nsproxy(old_ns);
+
+	if (!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC)))
+		return 0;
+
+	new_ns = clone_namespaces(old_ns);
+	if (!new_ns) {
+		err = -ENOMEM;
+		goto out;
+	}
+
+	tsk->nsproxy = new_ns;
+
+	err = copy_namespace(flags, tsk);
+	if (err)
+		goto out_ns;
+
+	err = copy_utsname(flags, tsk);
+	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;
+	kfree(new_ns);
+	goto out;
+}
+
+void free_nsproxy(struct nsproxy *ns)
+{
+		if (ns->namespace)
+			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);
+}