LXR linux/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
  16struct user_namespace;
  17extern struct user_namespace init_user_ns;
  18
  19typedef __kernel_uid32_t projid_t;
  20
  21typedef struct {
  22        projid_t val;
  23} kprojid_t;
  24
  25static 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
  35static inline bool projid_eq(kprojid_t left, kprojid_t right)
  36{
  37        return __kprojid_val(left) == __kprojid_val(right);
  38}
  39
  40static inline bool projid_lt(kprojid_t left, kprojid_t right)
  41{
  42        return __kprojid_val(left) < __kprojid_val(right);
  43}
  44
  45static inline bool projid_valid(kprojid_t projid)
  46{
  47        return !projid_eq(projid, INVALID_PROJID);
  48}
  49
  50#ifdef CONFIG_USER_NS
  51
  52extern kprojid_t make_kprojid(struct user_namespace *from, projid_t projid);
  53
  54extern projid_t from_kprojid(struct user_namespace *to, kprojid_t projid);
  55extern projid_t from_kprojid_munged(struct user_namespace *to, kprojid_t projid);
  56
  57static 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
  64static inline kprojid_t make_kprojid(struct user_namespace *from, projid_t projid)
  65{
  66        return KPROJIDT_INIT(projid);
  67}
  68
  69static inline projid_t from_kprojid(struct user_namespace *to, kprojid_t kprojid)
  70{
  71        return __kprojid_val(kprojid);
  72}
  73
  74static 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
  82static 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 */
  90