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/*

 *  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>

/*

 * 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);

}