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