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