Commit | Line | Data |
---|---|---|
ab516013 SH |
1 | #ifndef _LINUX_NSPROXY_H |
2 | #define _LINUX_NSPROXY_H | |
3 | ||
4 | #include <linux/spinlock.h> | |
5 | #include <linux/sched.h> | |
6 | ||
6b3286ed | 7 | struct mnt_namespace; |
4865ecf1 | 8 | struct uts_namespace; |
25b21cb2 | 9 | struct ipc_namespace; |
9a575a92 | 10 | struct pid_namespace; |
5ad4e53b | 11 | struct fs_struct; |
1651e14e | 12 | |
ab516013 SH |
13 | /* |
14 | * A structure to contain pointers to all per-process | |
15 | * namespaces - fs (mount), uts, network, sysvipc, etc. | |
16 | * | |
c2b1df2e AL |
17 | * 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 | * | |
ab516013 SH |
21 | * '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 | */ | |
29 | struct nsproxy { | |
30 | atomic_t count; | |
4865ecf1 | 31 | struct uts_namespace *uts_ns; |
25b21cb2 | 32 | struct ipc_namespace *ipc_ns; |
6b3286ed | 33 | struct mnt_namespace *mnt_ns; |
c2b1df2e | 34 | struct pid_namespace *pid_ns_for_children; |
772698f6 | 35 | struct net *net_ns; |
ab516013 SH |
36 | }; |
37 | extern struct nsproxy init_nsproxy; | |
38 | ||
cf7b708c PE |
39 | /* |
40 | * the namespaces access rules are: | |
41 | * | |
42 | * 1. only current task is allowed to change tsk->nsproxy pointer or | |
728dba3a EB |
43 | * any pointer on the nsproxy itself. Current must hold the task_lock |
44 | * when changing tsk->nsproxy. | |
cf7b708c PE |
45 | * |
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 | |
728dba3a EB |
50 | * task_lock(task); |
51 | * nsproxy = task->nsproxy; | |
cf7b708c PE |
52 | * if (nsproxy != NULL) { |
53 | * / * | |
54 | * * work with the namespaces here | |
55 | * * e.g. get the reference on one of them | |
56 | * * / | |
57 | * } / * | |
728dba3a | 58 | * * NULL task->nsproxy means that this task is |
cf7b708c PE |
59 | * * almost dead (zombie) |
60 | * * / | |
728dba3a | 61 | * task_unlock(task); |
cf7b708c PE |
62 | * |
63 | */ | |
64 | ||
213dd266 | 65 | int copy_namespaces(unsigned long flags, struct task_struct *tsk); |
cf7b708c PE |
66 | void exit_task_namespaces(struct task_struct *tsk); |
67 | void switch_task_namespaces(struct task_struct *tsk, struct nsproxy *new); | |
ab516013 | 68 | void free_nsproxy(struct nsproxy *ns); |
e3222c4e | 69 | int unshare_nsproxy_namespaces(unsigned long, struct nsproxy **, |
b2e0d987 | 70 | struct cred *, struct fs_struct *); |
66577193 | 71 | int __init nsproxy_cache_init(void); |
ab516013 | 72 | |
444f378b | 73 | static inline void put_nsproxy(struct nsproxy *ns) |
ab516013 | 74 | { |
444f378b | 75 | if (atomic_dec_and_test(&ns->count)) { |
ab516013 | 76 | free_nsproxy(ns); |
444f378b | 77 | } |
ab516013 SH |
78 | } |
79 | ||
cf7b708c | 80 | static inline void get_nsproxy(struct nsproxy *ns) |
ab516013 | 81 | { |
cf7b708c | 82 | atomic_inc(&ns->count); |
ab516013 | 83 | } |
858d72ea | 84 | |
ab516013 | 85 | #endif |