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 #ifdef CONFIG_UIDGID_STRICT_TYPE_CHECKS
  22
  23 typedef struct {
  24         projid_t val;
  25 } kprojid_t;
  26
  27 static inline projid_t __kprojid_val(kprojid_t projid)
  28 {
  29         return projid.val;
  30 }
  31
  32 #define KPROJIDT_INIT(value) (kprojid_t){ value }
  33
  34 #else
  35
  36 typedef projid_t kprojid_t;
  37
  38 static inline projid_t __kprojid_val(kprojid_t projid)
  39 {
  40         return projid;
  41 }
  42
  43 #define KPROJIDT_INIT(value) ((kprojid_t) value )
  44
  45 #endif
  46
  47 #define INVALID_PROJID KPROJIDT_INIT(-1)
  48 #define OVERFLOW_PROJID 65534
  49
  50 static inline bool projid_eq(kprojid_t left, kprojid_t right)
  51 {
  52         return __kprojid_val(left) == __kprojid_val(right);
  53 }
  54
  55 static inline bool projid_lt(kprojid_t left, kprojid_t right)
  56 {
  57         return __kprojid_val(left) < __kprojid_val(right);
  58 }
  59
  60 static inline bool projid_valid(kprojid_t projid)
  61 {
  62         return !projid_eq(projid, INVALID_PROJID);
  63 }
  64
  65 #ifdef CONFIG_USER_NS
  66
  67 extern kprojid_t make_kprojid(struct user_namespace *from, projid_t projid);
  68
  69 extern projid_t from_kprojid(struct user_namespace *to, kprojid_t projid);
  70 extern projid_t from_kprojid_munged(struct user_namespace *to, kprojid_t projid);
  71
  72 static inline bool kprojid_has_mapping(struct user_namespace *ns, kprojid_t projid)
  73 {
  74         return from_kprojid(ns, projid) != (projid_t)-1;
  75 }
  76
  77 #else
  78
  79 static inline kprojid_t make_kprojid(struct user_namespace *from, projid_t projid)
  80 {
  81         return KPROJIDT_INIT(projid);
  82 }
  83
  84 static inline projid_t from_kprojid(struct user_namespace *to, kprojid_t kprojid)
  85 {
  86         return __kprojid_val(kprojid);
  87 }
  88
  89 static inline projid_t from_kprojid_munged(struct user_namespace *to, kprojid_t kprojid)
  90 {
  91         projid_t projid = from_kprojid(to, kprojid);
  92         if (projid == (projid_t)-1)
  93                 projid = OVERFLOW_PROJID;
  94         return projid;
  95 }
  96
  97 static inline bool kprojid_has_mapping(struct user_namespace *ns, kprojid_t projid)
  98 {
  99         return true;
 100 }
 101
 102 #endif /* CONFIG_USER_NS */
 103
 104 #endif /* _LINUX_PROJID_H */