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