/* *  Copyright (C) 2004 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. */ #include <linux/module.h>#include <linux/uts.h>#include <linux/utsname.h>#include <linux/version.h>#include <linux/err.h>#include <linux/slab.h> /* * Clone a new ns copying an original utsname, setting refcount to 1 * @old_ns: namespace to clone * Return NULL on error (failure to kmalloc), new ns otherwise */static struct uts_namespace *clone_uts_ns(struct uts_namespace *old_ns){	struct uts_namespace *ns; 	ns = kmalloc(sizeof(struct uts_namespace), GFP_KERNEL);	if (!ns)		return ERR_PTR(-ENOMEM); 	down_read(&uts_sem);	memcpy(&ns->name, &old_ns->name, sizeof(ns->name));	up_read(&uts_sem);	kref_init(&ns->kref);	return ns;} /* * Copy task tsk's utsname namespace, or clone it if flags * specifies CLONE_NEWUTS.  In latter case, changes to the * utsname of this process won't be seen by parent, and vice * versa. */struct uts_namespace *copy_utsname(unsigned long flags, struct uts_namespace *old_ns){	struct uts_namespace *new_ns; 	BUG_ON(!old_ns);	get_uts_ns(old_ns); 	if (!(flags & CLONE_NEWUTS))		return old_ns; 	new_ns = clone_uts_ns(old_ns); 	put_uts_ns(old_ns);	return new_ns;} void free_uts_ns(struct kref *kref){	struct uts_namespace *ns; 	ns = container_of(kref, struct uts_namespace, kref);	kfree(ns);}