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 12struct user_namespace { 13 struct kref kref; 14 struct hlist_head uidhash_table[UIDHASH_SZ]; 15 struct user_struct *root_user; 16}; 17 18extern struct user_namespace init_user_ns; 19 20#ifdef CONFIG_USER_NS 21 22static 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 29extern struct user_namespace *copy_user_ns(int flags, 30 struct user_namespace *old_ns); 31extern void free_user_ns(struct kref *kref); 32 33static 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 41static inline struct user_namespace *get_user_ns(struct user_namespace *ns) 42{ 43 return &init_user_ns; 44} 45 46static 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 55static inline void put_user_ns(struct user_namespace *ns) 56{ 57} 58 59#endif 60 61#endif /* _LINUX_USER_H */ 62