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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>
/*
* 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) {
memcpy(&ns->name, &old_ns->name, sizeof(ns->name));
kref_init(&ns->kref);
}
return ns;
}
/*
* unshare the current process' utsname namespace.
* called only in sys_unshare()
*/
int unshare_utsname(unsigned long unshare_flags, struct uts_namespace **new_uts)
{
if (unshare_flags & CLONE_NEWUTS) {
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
*new_uts = clone_uts_ns(current->nsproxy->uts_ns);
if (!*new_uts)
return -ENOMEM;
}
return 0;
}
/*
* 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.
*/
int copy_utsname(int flags, struct task_struct *tsk)
{
struct uts_namespace *old_ns = tsk->nsproxy->uts_ns;
struct uts_namespace *new_ns;
int err = 0;
if (!old_ns)
return 0;
get_uts_ns(old_ns);
if (!(flags & CLONE_NEWUTS))
return 0;
if (!capable(CAP_SYS_ADMIN)) {
err = -EPERM;
goto out;
}
new_ns = clone_uts_ns(old_ns);
if (!new_ns) {
err = -ENOMEM;
goto out;
}
tsk->nsproxy->uts_ns = new_ns;
out:
put_uts_ns(old_ns);
return err;
}
void free_uts_ns(struct kref *kref)
{
struct uts_namespace *ns;
ns = container_of(kref, struct uts_namespace, kref);
kfree(ns);
}
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