1/*
  2 *  Copyright (C) 2004 IBM Corporation
  3 *
  4 *  Author: Serge Hallyn <serue@us.ibm.com>
  5 *
  6 *  This program is free software; you can redistribute it and/or
  7 *  modify it under the terms of the GNU General Public License as
  8 *  published by the Free Software Foundation, version 2 of the
  9 *  License.
 10 */
 11
 12#include <linux/export.h>
 13#include <linux/uts.h>
 14#include <linux/utsname.h>
 15#include <linux/err.h>
 16#include <linux/slab.h>
 17#include <linux/user_namespace.h>
 18#include <linux/proc_fs.h>
 19
 20static struct uts_namespace *create_uts_ns(void)
 21{
 22	struct uts_namespace *uts_ns;
 23
 24	uts_ns = kmalloc(sizeof(struct uts_namespace), GFP_KERNEL);
 25	if (uts_ns)
 26		kref_init(&uts_ns->kref);
 27	return uts_ns;
 28}
 29
 30/*
 31 * Clone a new ns copying an original utsname, setting refcount to 1
 32 * @old_ns: namespace to clone
 33 * Return NULL on error (failure to kmalloc), new ns otherwise
 34 */
 35static struct uts_namespace *clone_uts_ns(struct task_struct *tsk,
 36					  struct uts_namespace *old_ns)
 37{
 38	struct uts_namespace *ns;
 39
 40	ns = create_uts_ns();
 41	if (!ns)
 42		return ERR_PTR(-ENOMEM);
 43
 44	down_read(&uts_sem);
 45	memcpy(&ns->name, &old_ns->name, sizeof(ns->name));
 46	ns->user_ns = get_user_ns(task_cred_xxx(tsk, user_ns));
 47	up_read(&uts_sem);
 48	return ns;
 49}
 50
 51/*
 52 * Copy task tsk's utsname namespace, or clone it if flags
 53 * specifies CLONE_NEWUTS.  In latter case, changes to the
 54 * utsname of this process won't be seen by parent, and vice
 55 * versa.
 56 */
 57struct uts_namespace *copy_utsname(unsigned long flags,
 58				   struct task_struct *tsk)
 59{
 60	struct uts_namespace *old_ns = tsk->nsproxy->uts_ns;
 61	struct uts_namespace *new_ns;
 62
 63	BUG_ON(!old_ns);
 64	get_uts_ns(old_ns);
 65
 66	if (!(flags & CLONE_NEWUTS))
 67		return old_ns;
 68
 69	new_ns = clone_uts_ns(tsk, old_ns);
 70
 71	put_uts_ns(old_ns);
 72	return new_ns;
 73}
 74
 75void free_uts_ns(struct kref *kref)
 76{
 77	struct uts_namespace *ns;
 78
 79	ns = container_of(kref, struct uts_namespace, kref);
 80	put_user_ns(ns->user_ns);
 81	kfree(ns);
 82}
 83
 84static void *utsns_get(struct task_struct *task)
 85{
 86	struct uts_namespace *ns = NULL;
 87	struct nsproxy *nsproxy;
 88
 89	rcu_read_lock();
 90	nsproxy = task_nsproxy(task);
 91	if (nsproxy) {
 92		ns = nsproxy->uts_ns;
 93		get_uts_ns(ns);
 94	}
 95	rcu_read_unlock();
 96
 97	return ns;
 98}
 99
100static void utsns_put(void *ns)
101{
102	put_uts_ns(ns);
103}
104
105static int utsns_install(struct nsproxy *nsproxy, void *ns)
106{
107	get_uts_ns(ns);
108	put_uts_ns(nsproxy->uts_ns);
109	nsproxy->uts_ns = ns;
110	return 0;
111}
112
113const struct proc_ns_operations utsns_operations = {
114	.name		= "uts",
115	.type		= CLONE_NEWUTS,
116	.get		= utsns_get,
117	.put		= utsns_put,
118	.install	= utsns_install,
119};
120

  1/*
  2 *  Copyright (C) 2004 IBM Corporation
  3 *
  4 *  Author: Serge Hallyn <serue@us.ibm.com>
  5 *
  6 *  This program is free software; you can redistribute it and/or
  7 *  modify it under the terms of the GNU General Public License as
  8 *  published by the Free Software Foundation, version 2 of the
  9 *  License.
 10 */
 11
 12#include <linux/module.h>
 13#include <linux/uts.h>
 14#include <linux/utsname.h>
 15#include <linux/err.h>
 16#include <linux/slab.h>
 17#include <linux/user_namespace.h>
 18#include <linux/proc_fs.h>
 19
 20static struct uts_namespace *create_uts_ns(void)
 21{
 22	struct uts_namespace *uts_ns;
 23
 24	uts_ns = kmalloc(sizeof(struct uts_namespace), GFP_KERNEL);
 25	if (uts_ns)
 26		kref_init(&uts_ns->kref);
 27	return uts_ns;
 28}
 29
 30/*
 31 * Clone a new ns copying an original utsname, setting refcount to 1
 32 * @old_ns: namespace to clone
 33 * Return NULL on error (failure to kmalloc), new ns otherwise
 34 */
 35static struct uts_namespace *clone_uts_ns(struct task_struct *tsk,
 36					  struct uts_namespace *old_ns)
 37{
 38	struct uts_namespace *ns;
 39
 40	ns = create_uts_ns();
 41	if (!ns)
 42		return ERR_PTR(-ENOMEM);
 43
 44	down_read(&uts_sem);
 45	memcpy(&ns->name, &old_ns->name, sizeof(ns->name));
 46	ns->user_ns = get_user_ns(task_cred_xxx(tsk, user)->user_ns);
 47	up_read(&uts_sem);
 48	return ns;
 49}
 50
 51/*
 52 * Copy task tsk's utsname namespace, or clone it if flags
 53 * specifies CLONE_NEWUTS.  In latter case, changes to the
 54 * utsname of this process won't be seen by parent, and vice
 55 * versa.
 56 */
 57struct uts_namespace *copy_utsname(unsigned long flags,
 58				   struct task_struct *tsk)
 59{
 60	struct uts_namespace *old_ns = tsk->nsproxy->uts_ns;
 61	struct uts_namespace *new_ns;
 62
 63	BUG_ON(!old_ns);
 64	get_uts_ns(old_ns);
 65
 66	if (!(flags & CLONE_NEWUTS))
 67		return old_ns;
 68
 69	new_ns = clone_uts_ns(tsk, old_ns);
 70
 71	put_uts_ns(old_ns);
 72	return new_ns;
 73}
 74
 75void free_uts_ns(struct kref *kref)
 76{
 77	struct uts_namespace *ns;
 78
 79	ns = container_of(kref, struct uts_namespace, kref);
 80	put_user_ns(ns->user_ns);
 81	kfree(ns);
 82}
 83
 84static void *utsns_get(struct task_struct *task)
 85{
 86	struct uts_namespace *ns = NULL;
 87	struct nsproxy *nsproxy;
 88
 89	rcu_read_lock();
 90	nsproxy = task_nsproxy(task);
 91	if (nsproxy) {
 92		ns = nsproxy->uts_ns;
 93		get_uts_ns(ns);
 94	}
 95	rcu_read_unlock();
 96
 97	return ns;
 98}
 99
100static void utsns_put(void *ns)
101{
102	put_uts_ns(ns);
103}
104
105static int utsns_install(struct nsproxy *nsproxy, void *ns)
106{
107	get_uts_ns(ns);
108	put_uts_ns(nsproxy->uts_ns);
109	nsproxy->uts_ns = ns;
110	return 0;
111}
112
113const struct proc_ns_operations utsns_operations = {
114	.name		= "uts",
115	.type		= CLONE_NEWUTS,
116	.get		= utsns_get,
117	.put		= utsns_put,
118	.install	= utsns_install,
119};
120