projid.h 2.2 KB

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  1. /* SPDX-License-Identifier: GPL-2.0 */
  2. #ifndef _LINUX_PROJID_H
  3. #define _LINUX_PROJID_H
  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. struct user_namespace;
  16. extern struct user_namespace init_user_ns;
  17. typedef __kernel_uid32_t projid_t;
  18. typedef struct {
  19. projid_t val;
  20. } kprojid_t;
  21. static inline projid_t __kprojid_val(kprojid_t projid)
  22. {
  23. return projid.val;
  24. }
  25. #define KPROJIDT_INIT(value) (kprojid_t){ value }
  26. #define INVALID_PROJID KPROJIDT_INIT(-1)
  27. #define OVERFLOW_PROJID 65534
  28. static inline bool projid_eq(kprojid_t left, kprojid_t right)
  29. {
  30. return __kprojid_val(left) == __kprojid_val(right);
  31. }
  32. static inline bool projid_lt(kprojid_t left, kprojid_t right)
  33. {
  34. return __kprojid_val(left) < __kprojid_val(right);
  35. }
  36. static inline bool projid_valid(kprojid_t projid)
  37. {
  38. return !projid_eq(projid, INVALID_PROJID);
  39. }
  40. #ifdef CONFIG_USER_NS
  41. extern kprojid_t make_kprojid(struct user_namespace *from, projid_t projid);
  42. extern projid_t from_kprojid(struct user_namespace *to, kprojid_t projid);
  43. extern projid_t from_kprojid_munged(struct user_namespace *to, kprojid_t projid);
  44. static inline bool kprojid_has_mapping(struct user_namespace *ns, kprojid_t projid)
  45. {
  46. return from_kprojid(ns, projid) != (projid_t)-1;
  47. }
  48. #else
  49. static inline kprojid_t make_kprojid(struct user_namespace *from, projid_t projid)
  50. {
  51. return KPROJIDT_INIT(projid);
  52. }
  53. static inline projid_t from_kprojid(struct user_namespace *to, kprojid_t kprojid)
  54. {
  55. return __kprojid_val(kprojid);
  56. }
  57. static inline projid_t from_kprojid_munged(struct user_namespace *to, kprojid_t kprojid)
  58. {
  59. projid_t projid = from_kprojid(to, kprojid);
  60. if (projid == (projid_t)-1)
  61. projid = OVERFLOW_PROJID;
  62. return projid;
  63. }
  64. static inline bool kprojid_has_mapping(struct user_namespace *ns, kprojid_t projid)
  65. {
  66. return true;
  67. }
  68. #endif /* CONFIG_USER_NS */
  69. #endif /* _LINUX_PROJID_H */