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