1 #ifndef _LINUX_HIGHUID_H
2 #define _LINUX_HIGHUID_H
3
4 #include <linux/types.h>
5
6 /*
7 * general notes:
8 *
9 * CONFIG_UID16 is defined if the given architecture needs to
10 * support backwards compatibility for old system calls.
11 *
12 * kernel code should use uid_t and gid_t at all times when dealing with
13 * kernel-private data.
14 *
15 * old_uid_t and old_gid_t should only be different if CONFIG_UID16 is
16 * defined, else the platform should provide dummy typedefs for them
17 * such that they are equivalent to __kernel_{u,g}id_t.
18 *
19 * uid16_t and gid16_t are used on all architectures. (when dealing
20 * with structures hard coded to 16 bits, such as in filesystems)
21 */
22
23
24 /*
25 * This is the "overflow" UID and GID. They are used to signify uid/gid
26 * overflow to old programs when they request uid/gid information but are
27 * using the old 16 bit interfaces.
28 * When you run a libc5 program, it will think that all highuid files or
29 * processes are owned by this uid/gid.
30 * The idea is that it's better to do so than possibly return 0 in lieu of
31 * 65536, etc.
32 */
33
34 extern int overflowuid;
35 extern int overflowgid;
36
37 extern void __bad_uid(void);
38 extern void __bad_gid(void);
39
40 #define DEFAULT_OVERFLOWUID 65534
41 #define DEFAULT_OVERFLOWGID 65534
42
43 #ifdef CONFIG_UID16
44
45 /* prevent uid mod 65536 effect by returning a default value for high UIDs */
46 #define high2lowuid(uid) ((uid) & ~0xFFFF ? (old_uid_t)overflowuid : (old_uid_t)(uid))
47 #define high2lowgid(gid) ((gid) & ~0xFFFF ? (old_gid_t)overflowgid : (old_gid_t)(gid))
48 /*
49 * -1 is different in 16 bits than it is in 32 bits
50 * these macros are used by chown(), setreuid(), ...,
51 */
52 #define low2highuid(uid) ((uid) == (old_uid_t)-1 ? (uid_t)-1 : (uid_t)(uid))
53 #define low2highgid(gid) ((gid) == (old_gid_t)-1 ? (gid_t)-1 : (gid_t)(gid))
54
55 #define __convert_uid(size, uid) \
56 (size >= sizeof(uid) ? (uid) : high2lowuid(uid))
57 #define __convert_gid(size, gid) \
58 (size >= sizeof(gid) ? (gid) : high2lowgid(gid))
59
60
61 #else
62
63 #define __convert_uid(size, uid) (uid)
64 #define __convert_gid(size, gid) (gid)
65
66 #endif /* !CONFIG_UID16 */
67
68 /* uid/gid input should be always 32bit uid_t */
69 #define SET_UID(var, uid) do { (var) = __convert_uid(sizeof(var), (uid)); } while (0)
70 #define SET_GID(var, gid) do { (var) = __convert_gid(sizeof(var), (gid)); } while (0)
71
72 /*
73 * Everything below this line is needed on all architectures, to deal with
74 * filesystems that only store 16 bits of the UID/GID, etc.
75 */
76
77 /*
78 * This is the UID and GID that will get written to disk if a filesystem
79 * only supports 16-bit UIDs and the kernel has a high UID/GID to write
80 */
81 extern int fs_overflowuid;
82 extern int fs_overflowgid;
83
84 #define DEFAULT_FS_OVERFLOWUID 65534
85 #define DEFAULT_FS_OVERFLOWGID 65534
86
87 /*
88 * Since these macros are used in architectures that only need limited
89 * 16-bit UID back compatibility, we won't use old_uid_t and old_gid_t
90 */
91 #define fs_high2lowuid(uid) ((uid) & ~0xFFFF ? (uid16_t)fs_overflowuid : (uid16_t)(uid))
92 #define fs_high2lowgid(gid) ((gid) & ~0xFFFF ? (gid16_t)fs_overflowgid : (gid16_t)(gid))
93
94 #define low_16_bits(x) ((x) & 0xFFFF)
95 #define high_16_bits(x) (((x) & 0xFFFF0000) >> 16)
96
97 #endif /* _LINUX_HIGHUID_H */
98
|
This page was automatically generated by the
LXR engine.
|