1 #ifndef _LINUX_NSPROXY_H 2 #define _LINUX_NSPROXY_H 3 4 #include <linux/spinlock.h> 5 #include <linux/sched.h> 6 7 struct mnt_namespace; 8 struct uts_namespace; 9 struct ipc_namespace; 10 struct pid_namespace; 11 12 /* 13 * A structure to contain pointers to all per-process 14 * namespaces - fs (mount), uts, network, sysvipc, etc. 15 * 16 * 'count' is the number of tasks holding a reference. 17 * The count for each namespace, then, will be the number 18 * of nsproxies pointing to it, not the number of tasks. 19 * 20 * The nsproxy is shared by tasks which share all namespaces. 21 * As soon as a single namespace is cloned or unshared, the 22 * nsproxy is copied. 23 */ 24 struct nsproxy { 25 atomic_t count; 26 spinlock_t nslock; 27 struct uts_namespace *uts_ns; 28 struct ipc_namespace *ipc_ns; 29 struct mnt_namespace *mnt_ns; 30 struct pid_namespace *pid_ns; 31 }; 32 extern struct nsproxy init_nsproxy; 33 34 struct nsproxy *dup_namespaces(struct nsproxy *orig); 35 int copy_namespaces(int flags, struct task_struct *tsk); 36 void get_task_namespaces(struct task_struct *tsk); 37 void free_nsproxy(struct nsproxy *ns); 38 39 static inline void put_nsproxy(struct nsproxy *ns) 40 { 41 if (atomic_dec_and_test(&ns->count)) { 42 free_nsproxy(ns); 43 } 44 } 45 46 static inline void exit_task_namespaces(struct task_struct *p) 47 { 48 struct nsproxy *ns = p->nsproxy; 49 if (ns) { 50 task_lock(p); 51 p->nsproxy = NULL; 52 task_unlock(p); 53 put_nsproxy(ns); 54 } 55 } 56 #endif 57