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Serge E. Hallynab516012006-10-02 02:18:06 -07001#ifndef _LINUX_NSPROXY_H
2#define _LINUX_NSPROXY_H
3
4#include <linux/spinlock.h>
5#include <linux/sched.h>
6
Kirill Korotaev6b3286e2006-12-08 02:37:56 -08007struct mnt_namespace;
Serge E. Hallyn4865ecf2006-10-02 02:18:14 -07008struct uts_namespace;
Kirill Korotaev25b21cb2006-10-02 02:18:19 -07009struct ipc_namespace;
Cedric Le Goater9a575a92006-12-08 02:37:59 -080010struct pid_namespace;
Al Viro5ad4e532009-03-29 19:50:06 -040011struct fs_struct;
Serge E. Hallyn1651e142006-10-02 02:18:08 -070012
Serge E. Hallynab516012006-10-02 02:18:06 -070013/*
14 * A structure to contain pointers to all per-process
15 * namespaces - fs (mount), uts, network, sysvipc, etc.
16 *
Andy Lutomirskic2b1df22013-08-22 11:39:16 -070017 * The pid namespace is an exception -- it's accessed using
18 * task_active_pid_ns. The pid namespace here is the
19 * namespace that children will use.
20 *
Serge E. Hallynab516012006-10-02 02:18:06 -070021 * 'count' is the number of tasks holding a reference.
22 * The count for each namespace, then, will be the number
23 * of nsproxies pointing to it, not the number of tasks.
24 *
25 * The nsproxy is shared by tasks which share all namespaces.
26 * As soon as a single namespace is cloned or unshared, the
27 * nsproxy is copied.
28 */
29struct nsproxy {
30 atomic_t count;
Serge E. Hallyn4865ecf2006-10-02 02:18:14 -070031 struct uts_namespace *uts_ns;
Kirill Korotaev25b21cb2006-10-02 02:18:19 -070032 struct ipc_namespace *ipc_ns;
Kirill Korotaev6b3286e2006-12-08 02:37:56 -080033 struct mnt_namespace *mnt_ns;
Andy Lutomirskic2b1df22013-08-22 11:39:16 -070034 struct pid_namespace *pid_ns_for_children;
Eric W. Biederman772698f2007-09-12 11:55:17 +020035 struct net *net_ns;
Serge E. Hallynab516012006-10-02 02:18:06 -070036};
37extern struct nsproxy init_nsproxy;
38
Pavel Emelyanovcf7b7082007-10-18 23:39:54 -070039/*
40 * the namespaces access rules are:
41 *
42 * 1. only current task is allowed to change tsk->nsproxy pointer or
Eric W. Biederman728dba32014-02-03 19:13:49 -080043 * any pointer on the nsproxy itself. Current must hold the task_lock
44 * when changing tsk->nsproxy.
Pavel Emelyanovcf7b7082007-10-18 23:39:54 -070045 *
46 * 2. when accessing (i.e. reading) current task's namespaces - no
47 * precautions should be taken - just dereference the pointers
48 *
49 * 3. the access to other task namespaces is performed like this
Eric W. Biederman728dba32014-02-03 19:13:49 -080050 * task_lock(task);
51 * nsproxy = task->nsproxy;
Pavel Emelyanovcf7b7082007-10-18 23:39:54 -070052 * if (nsproxy != NULL) {
53 * / *
54 * * work with the namespaces here
55 * * e.g. get the reference on one of them
56 * * /
57 * } / *
Eric W. Biederman728dba32014-02-03 19:13:49 -080058 * * NULL task->nsproxy means that this task is
Pavel Emelyanovcf7b7082007-10-18 23:39:54 -070059 * * almost dead (zombie)
60 * * /
Eric W. Biederman728dba32014-02-03 19:13:49 -080061 * task_unlock(task);
Pavel Emelyanovcf7b7082007-10-18 23:39:54 -070062 *
63 */
64
Eric W. Biederman213dd262007-07-15 23:41:15 -070065int copy_namespaces(unsigned long flags, struct task_struct *tsk);
Pavel Emelyanovcf7b7082007-10-18 23:39:54 -070066void exit_task_namespaces(struct task_struct *tsk);
67void switch_task_namespaces(struct task_struct *tsk, struct nsproxy *new);
Serge E. Hallynab516012006-10-02 02:18:06 -070068void free_nsproxy(struct nsproxy *ns);
Badari Pulavartye3222c42007-05-08 00:25:21 -070069int unshare_nsproxy_namespaces(unsigned long, struct nsproxy **,
Eric W. Biedermanb2e0d9872012-07-26 05:15:35 -070070 struct cred *, struct fs_struct *);
Al Viro66577192011-06-28 15:41:10 -040071int __init nsproxy_cache_init(void);
Serge E. Hallynab516012006-10-02 02:18:06 -070072
Linus Torvalds444f3782007-01-30 13:35:18 -080073static inline void put_nsproxy(struct nsproxy *ns)
Serge E. Hallynab516012006-10-02 02:18:06 -070074{
Linus Torvalds444f3782007-01-30 13:35:18 -080075 if (atomic_dec_and_test(&ns->count)) {
Serge E. Hallynab516012006-10-02 02:18:06 -070076 free_nsproxy(ns);
Linus Torvalds444f3782007-01-30 13:35:18 -080077 }
Serge E. Hallynab516012006-10-02 02:18:06 -070078}
79
Pavel Emelyanovcf7b7082007-10-18 23:39:54 -070080static inline void get_nsproxy(struct nsproxy *ns)
Serge E. Hallynab516012006-10-02 02:18:06 -070081{
Pavel Emelyanovcf7b7082007-10-18 23:39:54 -070082 atomic_inc(&ns->count);
Serge E. Hallynab516012006-10-02 02:18:06 -070083}
Serge E. Hallyn858d72e2007-10-18 23:39:45 -070084
Serge E. Hallynab516012006-10-02 02:18:06 -070085#endif