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 list_head uidhash_table[UIDHASH_SZ]; 15 struct user_struct *root_user; 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 struct user_namespace *copy_user_ns(int flags, 30 struct user_namespace *old_ns); 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 struct user_namespace *copy_user_ns(int flags, 47 struct user_namespace *old_ns) 48 { 49 if (flags & CLONE_NEWUSER) 50 return ERR_PTR(-EINVAL); 51 52 return old_ns; 53 } 54 55 static inline void put_user_ns(struct user_namespace *ns) 56 { 57 } 58 59 #endif 60 61 #endif /* _LINUX_USER_H */ 62