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      *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 */