1 #ifndef _LINUX_USER_NAMESPACE_H 2 #define _LINUX_USER_NAMESPACE_H 3 4 #include <linux/kref.h> 5 #include <linux/nsproxy.h> 6 #include <linux/sched.h> 7 #include <linux/err.h> 8 9 #define UIDHASH_BITS (CONFIG_BASE_SMALL ? 3 : 8) 10 #define UIDHASH_SZ (1 << UIDHASH_BITS) 11 12 struct user_namespace { 13 struct kref kref; 14 struct hlist_head uidhash_table[UIDHASH_SZ]; 15 struct user_struct *creator; 16 struct work_struct destroyer; 17 }; 18 19 extern struct user_namespace init_user_ns; 20 21 #ifdef CONFIG_USER_NS 22 23 static inline struct user_namespace *get_user_ns(struct user_namespace *ns) 24 { 25 if (ns) 26 kref_get(&ns->kref); 27 return ns; 28 } 29 30 extern int create_user_ns(struct cred *new); 31 extern void free_user_ns(struct kref *kref); 32 33 static inline void put_user_ns(struct user_namespace *ns) 34 { 35 if (ns) 36 kref_put(&ns->kref, free_user_ns); 37 } 38 39 #else 40 41 static inline struct user_namespace *get_user_ns(struct user_namespace *ns) 42 { 43 return &init_user_ns; 44 } 45 46 static inline int create_user_ns(struct cred *new) 47 { 48 return -EINVAL; 49 } 50 51 static inline void put_user_ns(struct user_namespace *ns) 52 { 53 } 54 55 #endif 56 57 #endif /* _LINUX_USER_H */ 58