2 * Copyright (C) 2006 IBM Corporation
4 * Author: Serge Hallyn <serue@us.ibm.com>
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
11 * Jun 2006 - namespaces support
13 * Pavel Emelianov <xemul@openvz.org>
16 #include <linux/module.h>
17 #include <linux/nsproxy.h>
18 #include <linux/init_task.h>
19 #include <linux/mnt_namespace.h>
20 #include <linux/utsname.h>
21 #include <linux/pid_namespace.h>
22 #include <net/net_namespace.h>
23 #include <linux/ipc_namespace.h>
25 static struct kmem_cache *nsproxy_cachep;
27 struct nsproxy init_nsproxy = INIT_NSPROXY(init_nsproxy);
30 * creates a copy of "orig" with refcount 1.
32 static inline struct nsproxy *clone_nsproxy(struct nsproxy *orig)
36 ns = kmem_cache_alloc(nsproxy_cachep, GFP_KERNEL);
38 memcpy(ns, orig, sizeof(struct nsproxy));
39 atomic_set(&ns->count, 1);
45 * Create new nsproxy and all of its the associated namespaces.
46 * Return the newly created nsproxy. Do not attach this to the task,
47 * leave it to the caller to do proper locking and attach it to task.
49 static struct nsproxy *create_new_namespaces(unsigned long flags,
50 struct task_struct *tsk, struct fs_struct *new_fs)
52 struct nsproxy *new_nsp;
55 new_nsp = clone_nsproxy(tsk->nsproxy);
57 return ERR_PTR(-ENOMEM);
59 new_nsp->mnt_ns = copy_mnt_ns(flags, tsk->nsproxy->mnt_ns, new_fs);
60 if (IS_ERR(new_nsp->mnt_ns)) {
61 err = PTR_ERR(new_nsp->mnt_ns);
65 new_nsp->uts_ns = copy_utsname(flags, tsk->nsproxy->uts_ns);
66 if (IS_ERR(new_nsp->uts_ns)) {
67 err = PTR_ERR(new_nsp->uts_ns);
71 new_nsp->ipc_ns = copy_ipcs(flags, tsk->nsproxy->ipc_ns);
72 if (IS_ERR(new_nsp->ipc_ns)) {
73 err = PTR_ERR(new_nsp->ipc_ns);
77 new_nsp->pid_ns = copy_pid_ns(flags, task_active_pid_ns(tsk));
78 if (IS_ERR(new_nsp->pid_ns)) {
79 err = PTR_ERR(new_nsp->pid_ns);
83 new_nsp->net_ns = copy_net_ns(flags, tsk->nsproxy->net_ns);
84 if (IS_ERR(new_nsp->net_ns)) {
85 err = PTR_ERR(new_nsp->net_ns);
93 put_pid_ns(new_nsp->pid_ns);
96 put_ipc_ns(new_nsp->ipc_ns);
99 put_uts_ns(new_nsp->uts_ns);
102 put_mnt_ns(new_nsp->mnt_ns);
104 kmem_cache_free(nsproxy_cachep, new_nsp);
109 * called from clone. This now handles copy for nsproxy and all
110 * namespaces therein.
112 int copy_namespaces(unsigned long flags, struct task_struct *tsk)
114 struct nsproxy *old_ns = tsk->nsproxy;
115 struct nsproxy *new_ns;
123 if (!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
124 CLONE_NEWPID | CLONE_NEWNET)))
127 if (!capable(CAP_SYS_ADMIN)) {
133 * CLONE_NEWIPC must detach from the undolist: after switching
134 * to a new ipc namespace, the semaphore arrays from the old
135 * namespace are unreachable. In clone parlance, CLONE_SYSVSEM
136 * means share undolist with parent, so we must forbid using
137 * it along with CLONE_NEWIPC.
139 if ((flags & CLONE_NEWIPC) && (flags & CLONE_SYSVSEM)) {
144 new_ns = create_new_namespaces(flags, tsk, tsk->fs);
145 if (IS_ERR(new_ns)) {
146 err = PTR_ERR(new_ns);
150 tsk->nsproxy = new_ns;
157 void free_nsproxy(struct nsproxy *ns)
160 put_mnt_ns(ns->mnt_ns);
162 put_uts_ns(ns->uts_ns);
164 put_ipc_ns(ns->ipc_ns);
166 put_pid_ns(ns->pid_ns);
168 kmem_cache_free(nsproxy_cachep, ns);
172 * Called from unshare. Unshare all the namespaces part of nsproxy.
173 * On success, returns the new nsproxy.
175 int unshare_nsproxy_namespaces(unsigned long unshare_flags,
176 struct nsproxy **new_nsp, struct fs_struct *new_fs)
180 if (!(unshare_flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
184 if (!capable(CAP_SYS_ADMIN))
187 *new_nsp = create_new_namespaces(unshare_flags, current,
188 new_fs ? new_fs : current->fs);
189 if (IS_ERR(*new_nsp)) {
190 err = PTR_ERR(*new_nsp);
194 err = ns_cgroup_clone(current, task_pid(current));
196 put_nsproxy(*new_nsp);
202 void switch_task_namespaces(struct task_struct *p, struct nsproxy *new)
210 rcu_assign_pointer(p->nsproxy, new);
212 if (ns && atomic_dec_and_test(&ns->count)) {
214 * wait for others to get what they want from this nsproxy.
216 * cannot release this nsproxy via the call_rcu() since
217 * put_mnt_ns() will want to sleep
224 void exit_task_namespaces(struct task_struct *p)
226 switch_task_namespaces(p, NULL);
229 static int __init nsproxy_cache_init(void)
231 nsproxy_cachep = KMEM_CACHE(nsproxy, SLAB_PANIC);
235 module_init(nsproxy_cache_init);