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 }; 17 18 extern struct user_namespace init_user_ns; 19 20 #ifdef CONFIG_USER_NS 21 22 static inline struct user_namespace *get_user_ns(struct user_namespace *ns) 23 { 24 if (ns) 25 kref_get(&ns->kref); 26 return ns; 27 } 28 29 extern int create_user_ns(struct cred *new); 30 extern void free_user_ns(struct kref *kref); 31 32 static inline void put_user_ns(struct user_namespace *ns) 33 { 34 if (ns) 35 kref_put(&ns->kref, free_user_ns); 36 } 37 38 #else 39 40 static inline struct user_namespace *get_user_ns(struct user_namespace *ns) 41 { 42 return &init_user_ns; 43 } 44 45 static inline int create_user_ns(struct cred *new) 46 { 47 return -EINVAL; 48 } 49 50 static inline void put_user_ns(struct user_namespace *ns) 51 { 52 } 53 54 #endif 55 56 #endif /* _LINUX_USER_H */ 57