1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_NSPROXY_H
3 #define _LINUX_NSPROXY_H
5 #include <linux/refcount.h>
6 #include <linux/spinlock.h>
7 #include <linux/sched.h>
13 struct cgroup_namespace;
17 * A structure to contain pointers to all per-process
18 * namespaces - fs (mount), uts, network, sysvipc, etc.
20 * The pid namespace is an exception -- it's accessed using
21 * task_active_pid_ns. The pid namespace here is the
22 * namespace that children will use.
24 * 'count' is the number of tasks holding a reference.
25 * The count for each namespace, then, will be the number
26 * of nsproxies pointing to it, not the number of tasks.
28 * The nsproxy is shared by tasks which share all namespaces.
29 * As soon as a single namespace is cloned or unshared, the
34 struct uts_namespace *uts_ns;
35 struct ipc_namespace *ipc_ns;
36 struct mnt_namespace *mnt_ns;
37 struct pid_namespace *pid_ns_for_children;
39 struct time_namespace *time_ns;
40 struct time_namespace *time_ns_for_children;
41 struct cgroup_namespace *cgroup_ns;
43 extern struct nsproxy init_nsproxy;
46 * A structure to encompass all bits needed to install
47 * a partial or complete new set of namespaces.
49 * If a new user namespace is requested cred will
50 * point to a modifiable set of credentials. If a pointer
51 * to a modifiable set is needed nsset_cred() must be
56 struct nsproxy *nsproxy;
58 const struct cred *cred;
61 static inline struct cred *nsset_cred(struct nsset *set)
63 if (set->flags & CLONE_NEWUSER)
64 return (struct cred *)set->cred;
70 * the namespaces access rules are:
72 * 1. only current task is allowed to change tsk->nsproxy pointer or
73 * any pointer on the nsproxy itself. Current must hold the task_lock
74 * when changing tsk->nsproxy.
76 * 2. when accessing (i.e. reading) current task's namespaces - no
77 * precautions should be taken - just dereference the pointers
79 * 3. the access to other task namespaces is performed like this
81 * nsproxy = task->nsproxy;
82 * if (nsproxy != NULL) {
84 * * work with the namespaces here
85 * * e.g. get the reference on one of them
88 * * NULL task->nsproxy means that this task is
89 * * almost dead (zombie)
95 int copy_namespaces(unsigned long flags, struct task_struct *tsk);
96 void exit_task_namespaces(struct task_struct *tsk);
97 void switch_task_namespaces(struct task_struct *tsk, struct nsproxy *new);
98 int exec_task_namespaces(void);
99 void free_nsproxy(struct nsproxy *ns);
100 int unshare_nsproxy_namespaces(unsigned long, struct nsproxy **,
101 struct cred *, struct fs_struct *);
102 int __init nsproxy_cache_init(void);
104 static inline void put_nsproxy(struct nsproxy *ns)
106 if (refcount_dec_and_test(&ns->count))
110 static inline void get_nsproxy(struct nsproxy *ns)
112 refcount_inc(&ns->count);