include/linux/nsproxy.h

   1 #ifndef _LINUX_NSPROXY_H
   2 #define _LINUX_NSPROXY_H
   3
   4 #include <linux/spinlock.h>
   5 #include <linux/sched.h>
   6
   7 struct namespace;
   8 struct uts_namespace;
   9 struct ipc_namespace;
  10
  11 /*
  12  * A structure to contain pointers to all per-process
  13  * namespaces - fs (mount), uts, network, sysvipc, etc.
  14  *
  15  * 'count' is the number of tasks holding a reference.
  16  * The count for each namespace, then, will be the number
  17  * of nsproxies pointing to it, not the number of tasks.
  18  *
  19  * The nsproxy is shared by tasks which share all namespaces.
  20  * As soon as a single namespace is cloned or unshared, the
  21  * nsproxy is copied.
  22  */
  23 struct nsproxy {
  24         atomic_t count;
  25         spinlock_t nslock;
  26         struct uts_namespace *uts_ns;
  27         struct ipc_namespace *ipc_ns;
  28         struct namespace *namespace;
  29 };
  30 extern struct nsproxy init_nsproxy;
  31
  32 struct nsproxy *dup_namespaces(struct nsproxy *orig);
  33 int copy_namespaces(int flags, struct task_struct *tsk);
  34 void get_task_namespaces(struct task_struct *tsk);
  35 void free_nsproxy(struct nsproxy *ns);
  36
  37 static inline void put_nsproxy(struct nsproxy *ns)
  38 {
  39         if (atomic_dec_and_test(&ns->count)) {
  40                 free_nsproxy(ns);
  41         }
  42 }
  43
  44 static inline void exit_task_namespaces(struct task_struct *p)
  45 {
  46         struct nsproxy *ns = p->nsproxy;
  47         if (ns) {
  48                 task_lock(p);
  49                 p->nsproxy = NULL;
  50                 task_unlock(p);
  51                 put_nsproxy(ns);
  52         }
  53 }
  54 #endif