include/linux/projid.h

   1 #ifndef _LINUX_PROJID_H
   2 #define _LINUX_PROJID_H
   3
   4 /*
   5  * A set of types for the internal kernel types representing project ids.
   6  *
   7  * The types defined in this header allow distinguishing which project ids in
   8  * the kernel are values used by userspace and which project id values are
   9  * the internal kernel values.  With the addition of user namespaces the values
  10  * can be different.  Using the type system makes it possible for the compiler
  11  * to detect when we overlook these differences.
  12  *
  13  */
  14 #include <linux/types.h>
  15
  16 struct user_namespace;
  17 extern struct user_namespace init_user_ns;
  18
  19 typedef __kernel_uid32_t projid_t;
  20
  21 typedef struct {
  22         projid_t val;
  23 } kprojid_t;
  24
  25 static inline projid_t __kprojid_val(kprojid_t projid)
  26 {
  27         return projid.val;
  28 }
  29
  30 #define KPROJIDT_INIT(value) (kprojid_t){ value }
  31
  32 #define INVALID_PROJID KPROJIDT_INIT(-1)
  33 #define OVERFLOW_PROJID 65534
  34
  35 static inline bool projid_eq(kprojid_t left, kprojid_t right)
  36 {
  37         return __kprojid_val(left) == __kprojid_val(right);
  38 }
  39
  40 static inline bool projid_lt(kprojid_t left, kprojid_t right)
  41 {
  42         return __kprojid_val(left) < __kprojid_val(right);
  43 }
  44
  45 static inline bool projid_valid(kprojid_t projid)
  46 {
  47         return !projid_eq(projid, INVALID_PROJID);
  48 }
  49
  50 #ifdef CONFIG_USER_NS
  51
  52 extern kprojid_t make_kprojid(struct user_namespace *from, projid_t projid);
  53
  54 extern projid_t from_kprojid(struct user_namespace *to, kprojid_t projid);
  55 extern projid_t from_kprojid_munged(struct user_namespace *to, kprojid_t projid);
  56
  57 static inline bool kprojid_has_mapping(struct user_namespace *ns, kprojid_t projid)
  58 {
  59         return from_kprojid(ns, projid) != (projid_t)-1;
  60 }
  61
  62 #else
  63
  64 static inline kprojid_t make_kprojid(struct user_namespace *from, projid_t projid)
  65 {
  66         return KPROJIDT_INIT(projid);
  67 }
  68
  69 static inline projid_t from_kprojid(struct user_namespace *to, kprojid_t kprojid)
  70 {
  71         return __kprojid_val(kprojid);
  72 }
  73
  74 static inline projid_t from_kprojid_munged(struct user_namespace *to, kprojid_t kprojid)
  75 {
  76         projid_t projid = from_kprojid(to, kprojid);
  77         if (projid == (projid_t)-1)
  78                 projid = OVERFLOW_PROJID;
  79         return projid;
  80 }
  81
  82 static inline bool kprojid_has_mapping(struct user_namespace *ns, kprojid_t projid)
  83 {
  84         return true;
  85 }
  86
  87 #endif /* CONFIG_USER_NS */
  88
  89 #endif /* _LINUX_PROJID_H */