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