include/linux/user_namespace.h

   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 */