linux/include/linux/projid.h
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   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
  21#ifdef CONFIG_UIDGID_STRICT_TYPE_CHECKS
  22
  23typedef struct {
  24        projid_t val;
  25} kprojid_t;
  26
  27static 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
  36typedef projid_t kprojid_t;
  37
  38static 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
  50static inline bool projid_eq(kprojid_t left, kprojid_t right)
  51{
  52        return __kprojid_val(left) == __kprojid_val(right);
  53}
  54
  55static inline bool projid_lt(kprojid_t left, kprojid_t right)
  56{
  57        return __kprojid_val(left) < __kprojid_val(right);
  58}
  59
  60static inline bool projid_valid(kprojid_t projid)
  61{
  62        return !projid_eq(projid, INVALID_PROJID);
  63}
  64
  65#ifdef CONFIG_USER_NS
  66
  67extern kprojid_t make_kprojid(struct user_namespace *from, projid_t projid);
  68
  69extern projid_t from_kprojid(struct user_namespace *to, kprojid_t projid);
  70extern projid_t from_kprojid_munged(struct user_namespace *to, kprojid_t projid);
  71
  72static 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
  79static inline kprojid_t make_kprojid(struct user_namespace *from, projid_t projid)
  80{
  81        return KPROJIDT_INIT(projid);
  82}
  83
  84static inline projid_t from_kprojid(struct user_namespace *to, kprojid_t kprojid)
  85{
  86        return __kprojid_val(kprojid);
  87}
  88
  89static 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
  97static 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 */
 105
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