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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
ab516013 SH |
2 | #ifndef _LINUX_NSPROXY_H |
3 | #define _LINUX_NSPROXY_H | |
4 | ||
5 | #include <linux/spinlock.h> | |
6 | #include <linux/sched.h> | |
7 | ||
6b3286ed | 8 | struct mnt_namespace; |
4865ecf1 | 9 | struct uts_namespace; |
25b21cb2 | 10 | struct ipc_namespace; |
9a575a92 | 11 | struct pid_namespace; |
a79a908f | 12 | struct cgroup_namespace; |
5ad4e53b | 13 | struct fs_struct; |
1651e14e | 14 | |
ab516013 SH |
15 | /* |
16 | * A structure to contain pointers to all per-process | |
17 | * namespaces - fs (mount), uts, network, sysvipc, etc. | |
18 | * | |
c2b1df2e AL |
19 | * The pid namespace is an exception -- it's accessed using |
20 | * task_active_pid_ns. The pid namespace here is the | |
21 | * namespace that children will use. | |
22 | * | |
ab516013 SH |
23 | * 'count' is the number of tasks holding a reference. |
24 | * The count for each namespace, then, will be the number | |
25 | * of nsproxies pointing to it, not the number of tasks. | |
26 | * | |
27 | * The nsproxy is shared by tasks which share all namespaces. | |
28 | * As soon as a single namespace is cloned or unshared, the | |
29 | * nsproxy is copied. | |
30 | */ | |
31 | struct nsproxy { | |
32 | atomic_t count; | |
4865ecf1 | 33 | struct uts_namespace *uts_ns; |
25b21cb2 | 34 | struct ipc_namespace *ipc_ns; |
6b3286ed | 35 | struct mnt_namespace *mnt_ns; |
c2b1df2e | 36 | struct pid_namespace *pid_ns_for_children; |
772698f6 | 37 | struct net *net_ns; |
a79a908f | 38 | struct cgroup_namespace *cgroup_ns; |
ab516013 SH |
39 | }; |
40 | extern struct nsproxy init_nsproxy; | |
41 | ||
cf7b708c PE |
42 | /* |
43 | * the namespaces access rules are: | |
44 | * | |
45 | * 1. only current task is allowed to change tsk->nsproxy pointer or | |
728dba3a EB |
46 | * any pointer on the nsproxy itself. Current must hold the task_lock |
47 | * when changing tsk->nsproxy. | |
cf7b708c PE |
48 | * |
49 | * 2. when accessing (i.e. reading) current task's namespaces - no | |
50 | * precautions should be taken - just dereference the pointers | |
51 | * | |
52 | * 3. the access to other task namespaces is performed like this | |
728dba3a EB |
53 | * task_lock(task); |
54 | * nsproxy = task->nsproxy; | |
cf7b708c PE |
55 | * if (nsproxy != NULL) { |
56 | * / * | |
57 | * * work with the namespaces here | |
58 | * * e.g. get the reference on one of them | |
59 | * * / | |
60 | * } / * | |
728dba3a | 61 | * * NULL task->nsproxy means that this task is |
cf7b708c PE |
62 | * * almost dead (zombie) |
63 | * * / | |
728dba3a | 64 | * task_unlock(task); |
cf7b708c PE |
65 | * |
66 | */ | |
67 | ||
213dd266 | 68 | int copy_namespaces(unsigned long flags, struct task_struct *tsk); |
cf7b708c PE |
69 | void exit_task_namespaces(struct task_struct *tsk); |
70 | void switch_task_namespaces(struct task_struct *tsk, struct nsproxy *new); | |
ab516013 | 71 | void free_nsproxy(struct nsproxy *ns); |
e3222c4e | 72 | int unshare_nsproxy_namespaces(unsigned long, struct nsproxy **, |
b2e0d987 | 73 | struct cred *, struct fs_struct *); |
66577193 | 74 | int __init nsproxy_cache_init(void); |
ab516013 | 75 | |
444f378b | 76 | static inline void put_nsproxy(struct nsproxy *ns) |
ab516013 | 77 | { |
444f378b | 78 | if (atomic_dec_and_test(&ns->count)) { |
ab516013 | 79 | free_nsproxy(ns); |
444f378b | 80 | } |
ab516013 SH |
81 | } |
82 | ||
cf7b708c | 83 | static inline void get_nsproxy(struct nsproxy *ns) |
ab516013 | 84 | { |
cf7b708c | 85 | atomic_inc(&ns->count); |
ab516013 | 86 | } |
858d72ea | 87 | |
ab516013 | 88 | #endif |