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 struct user_namespace {
  10         struct kref             kref;
  11         struct user_namespace   *parent;
  12         struct user_struct      *creator;
  13         struct work_struct      destroyer;
  14 };
  15
  16 extern struct user_namespace init_user_ns;
  17
  18 #ifdef CONFIG_USER_NS
  19
  20 static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
  21 {
  22         if (ns)
  23                 kref_get(&ns->kref);
  24         return ns;
  25 }
  26
  27 extern int create_user_ns(struct cred *new);
  28 extern void free_user_ns(struct kref *kref);
  29
  30 static inline void put_user_ns(struct user_namespace *ns)
  31 {
  32         if (ns)
  33                 kref_put(&ns->kref, free_user_ns);
  34 }
  35
  36 uid_t user_ns_map_uid(struct user_namespace *to, const struct cred *cred, uid_t uid);
  37 gid_t user_ns_map_gid(struct user_namespace *to, const struct cred *cred, gid_t gid);
  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 int create_user_ns(struct cred *new)
  47 {
  48         return -EINVAL;
  49 }
  50
  51 static inline void put_user_ns(struct user_namespace *ns)
  52 {
  53 }
  54
  55 static inline uid_t user_ns_map_uid(struct user_namespace *to,
  56         const struct cred *cred, uid_t uid)
  57 {
  58         return uid;
  59 }
  60 static inline gid_t user_ns_map_gid(struct user_namespace *to,
  61         const struct cred *cred, gid_t gid)
  62 {
  63         return gid;
  64 }
  65
  66 #endif
  67
  68 #endif /* _LINUX_USER_H */