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cfd280c9 CD |
1 | /* |
2 | * Compatibility interface for userspace libc header coordination: | |
3 | * | |
4 | * Define compatibility macros that are used to control the inclusion or | |
5 | * exclusion of UAPI structures and definitions in coordination with another | |
6 | * userspace C library. | |
7 | * | |
8 | * This header is intended to solve the problem of UAPI definitions that | |
9 | * conflict with userspace definitions. If a UAPI header has such conflicting | |
10 | * definitions then the solution is as follows: | |
11 | * | |
12 | * * Synchronize the UAPI header and the libc headers so either one can be | |
13 | * used and such that the ABI is preserved. If this is not possible then | |
14 | * no simple compatibility interface exists (you need to write translating | |
15 | * wrappers and rename things) and you can't use this interface. | |
16 | * | |
17 | * Then follow this process: | |
18 | * | |
19 | * (a) Include libc-compat.h in the UAPI header. | |
20 | * e.g. #include <linux/libc-compat.h> | |
21 | * This include must be as early as possible. | |
22 | * | |
23 | * (b) In libc-compat.h add enough code to detect that the comflicting | |
24 | * userspace libc header has been included first. | |
25 | * | |
26 | * (c) If the userspace libc header has been included first define a set of | |
27 | * guard macros of the form __UAPI_DEF_FOO and set their values to 1, else | |
28 | * set their values to 0. | |
29 | * | |
30 | * (d) Back in the UAPI header with the conflicting definitions, guard the | |
31 | * definitions with: | |
32 | * #if __UAPI_DEF_FOO | |
33 | * ... | |
34 | * #endif | |
35 | * | |
36 | * This fixes the situation where the linux headers are included *after* the | |
37 | * libc headers. To fix the problem with the inclusion in the other order the | |
38 | * userspace libc headers must be fixed like this: | |
39 | * | |
40 | * * For all definitions that conflict with kernel definitions wrap those | |
41 | * defines in the following: | |
42 | * #if !__UAPI_DEF_FOO | |
43 | * ... | |
44 | * #endif | |
45 | * | |
46 | * This prevents the redefinition of a construct already defined by the kernel. | |
47 | */ | |
48 | #ifndef _UAPI_LIBC_COMPAT_H | |
49 | #define _UAPI_LIBC_COMPAT_H | |
50 | ||
51 | /* We have included glibc headers... */ | |
52 | #if defined(__GLIBC__) | |
53 | ||
4a91cb61 MR |
54 | /* Coordinate with glibc net/if.h header. */ |
55 | #if defined(_NET_IF_H) | |
56 | ||
57 | /* GLIBC headers included first so don't define anything | |
58 | * that would already be defined. */ | |
59 | ||
60 | #define __UAPI_DEF_IF_IFCONF 0 | |
61 | #define __UAPI_DEF_IF_IFMAP 0 | |
62 | #define __UAPI_DEF_IF_IFNAMSIZ 0 | |
63 | #define __UAPI_DEF_IF_IFREQ 0 | |
64 | /* Everything up to IFF_DYNAMIC, matches net/if.h until glibc 2.23 */ | |
65 | #define __UAPI_DEF_IF_NET_DEVICE_FLAGS 0 | |
66 | /* For the future if glibc adds IFF_LOWER_UP, IFF_DORMANT and IFF_ECHO */ | |
67 | #ifndef __UAPI_DEF_IF_NET_DEVICE_FLAGS_LOWER_UP_DORMANT_ECHO | |
68 | #define __UAPI_DEF_IF_NET_DEVICE_FLAGS_LOWER_UP_DORMANT_ECHO 1 | |
69 | #endif /* __UAPI_DEF_IF_NET_DEVICE_FLAGS_LOWER_UP_DORMANT_ECHO */ | |
70 | ||
71 | #else /* _NET_IF_H */ | |
72 | ||
73 | /* Linux headers included first, and we must define everything | |
74 | * we need. The expectation is that glibc will check the | |
75 | * __UAPI_DEF_* defines and adjust appropriately. */ | |
76 | ||
77 | #define __UAPI_DEF_IF_IFCONF 1 | |
78 | #define __UAPI_DEF_IF_IFMAP 1 | |
79 | #define __UAPI_DEF_IF_IFNAMSIZ 1 | |
80 | #define __UAPI_DEF_IF_IFREQ 1 | |
81 | /* Everything up to IFF_DYNAMIC, matches net/if.h until glibc 2.23 */ | |
82 | #define __UAPI_DEF_IF_NET_DEVICE_FLAGS 1 | |
83 | /* For the future if glibc adds IFF_LOWER_UP, IFF_DORMANT and IFF_ECHO */ | |
84 | #define __UAPI_DEF_IF_NET_DEVICE_FLAGS_LOWER_UP_DORMANT_ECHO 1 | |
85 | ||
86 | #endif /* _NET_IF_H */ | |
87 | ||
cfd280c9 CD |
88 | /* Coordinate with glibc netinet/in.h header. */ |
89 | #if defined(_NETINET_IN_H) | |
90 | ||
91 | /* GLIBC headers included first so don't define anything | |
92 | * that would already be defined. */ | |
279c6c7f SH |
93 | #define __UAPI_DEF_IN_ADDR 0 |
94 | #define __UAPI_DEF_IN_IPPROTO 0 | |
95 | #define __UAPI_DEF_IN_PKTINFO 0 | |
96 | #define __UAPI_DEF_IP_MREQ 0 | |
97 | #define __UAPI_DEF_SOCKADDR_IN 0 | |
98 | #define __UAPI_DEF_IN_CLASS 0 | |
99 | ||
cfd280c9 CD |
100 | #define __UAPI_DEF_IN6_ADDR 0 |
101 | /* The exception is the in6_addr macros which must be defined | |
102 | * if the glibc code didn't define them. This guard matches | |
103 | * the guard in glibc/inet/netinet/in.h which defines the | |
104 | * additional in6_addr macros e.g. s6_addr16, and s6_addr32. */ | |
105 | #if defined(__USE_MISC) || defined (__USE_GNU) | |
106 | #define __UAPI_DEF_IN6_ADDR_ALT 0 | |
107 | #else | |
108 | #define __UAPI_DEF_IN6_ADDR_ALT 1 | |
109 | #endif | |
110 | #define __UAPI_DEF_SOCKADDR_IN6 0 | |
111 | #define __UAPI_DEF_IPV6_MREQ 0 | |
112 | #define __UAPI_DEF_IPPROTO_V6 0 | |
6d08acd2 | 113 | #define __UAPI_DEF_IPV6_OPTIONS 0 |
3b50d902 WC |
114 | #define __UAPI_DEF_IN6_PKTINFO 0 |
115 | #define __UAPI_DEF_IP6_MTUINFO 0 | |
cfd280c9 CD |
116 | |
117 | #else | |
118 | ||
119 | /* Linux headers included first, and we must define everything | |
120 | * we need. The expectation is that glibc will check the | |
121 | * __UAPI_DEF_* defines and adjust appropriately. */ | |
279c6c7f SH |
122 | #define __UAPI_DEF_IN_ADDR 1 |
123 | #define __UAPI_DEF_IN_IPPROTO 1 | |
124 | #define __UAPI_DEF_IN_PKTINFO 1 | |
125 | #define __UAPI_DEF_IP_MREQ 1 | |
126 | #define __UAPI_DEF_SOCKADDR_IN 1 | |
127 | #define __UAPI_DEF_IN_CLASS 1 | |
128 | ||
cfd280c9 CD |
129 | #define __UAPI_DEF_IN6_ADDR 1 |
130 | /* We unconditionally define the in6_addr macros and glibc must | |
131 | * coordinate. */ | |
132 | #define __UAPI_DEF_IN6_ADDR_ALT 1 | |
133 | #define __UAPI_DEF_SOCKADDR_IN6 1 | |
134 | #define __UAPI_DEF_IPV6_MREQ 1 | |
135 | #define __UAPI_DEF_IPPROTO_V6 1 | |
6d08acd2 | 136 | #define __UAPI_DEF_IPV6_OPTIONS 1 |
3b50d902 WC |
137 | #define __UAPI_DEF_IN6_PKTINFO 1 |
138 | #define __UAPI_DEF_IP6_MTUINFO 1 | |
cfd280c9 CD |
139 | |
140 | #endif /* _NETINET_IN_H */ | |
141 | ||
ea1a8217 SH |
142 | /* Definitions for xattr.h */ |
143 | #if defined(_SYS_XATTR_H) | |
144 | #define __UAPI_DEF_XATTR 0 | |
145 | #else | |
146 | #define __UAPI_DEF_XATTR 1 | |
147 | #endif | |
cfd280c9 CD |
148 | |
149 | /* If we did not see any headers from any supported C libraries, | |
150 | * or we are being included in the kernel, then define everything | |
151 | * that we need. */ | |
152 | #else /* !defined(__GLIBC__) */ | |
153 | ||
4a91cb61 MR |
154 | /* Definitions for if.h */ |
155 | #define __UAPI_DEF_IF_IFCONF 1 | |
156 | #define __UAPI_DEF_IF_IFMAP 1 | |
157 | #define __UAPI_DEF_IF_IFNAMSIZ 1 | |
158 | #define __UAPI_DEF_IF_IFREQ 1 | |
159 | /* Everything up to IFF_DYNAMIC, matches net/if.h until glibc 2.23 */ | |
160 | #define __UAPI_DEF_IF_NET_DEVICE_FLAGS 1 | |
161 | /* For the future if glibc adds IFF_LOWER_UP, IFF_DORMANT and IFF_ECHO */ | |
162 | #define __UAPI_DEF_IF_NET_DEVICE_FLAGS_LOWER_UP_DORMANT_ECHO 1 | |
163 | ||
279c6c7f SH |
164 | /* Definitions for in.h */ |
165 | #define __UAPI_DEF_IN_ADDR 1 | |
166 | #define __UAPI_DEF_IN_IPPROTO 1 | |
167 | #define __UAPI_DEF_IN_PKTINFO 1 | |
168 | #define __UAPI_DEF_IP_MREQ 1 | |
169 | #define __UAPI_DEF_SOCKADDR_IN 1 | |
170 | #define __UAPI_DEF_IN_CLASS 1 | |
171 | ||
cfd280c9 CD |
172 | /* Definitions for in6.h */ |
173 | #define __UAPI_DEF_IN6_ADDR 1 | |
174 | #define __UAPI_DEF_IN6_ADDR_ALT 1 | |
175 | #define __UAPI_DEF_SOCKADDR_IN6 1 | |
176 | #define __UAPI_DEF_IPV6_MREQ 1 | |
177 | #define __UAPI_DEF_IPPROTO_V6 1 | |
6d08acd2 | 178 | #define __UAPI_DEF_IPV6_OPTIONS 1 |
3b50d902 WC |
179 | #define __UAPI_DEF_IN6_PKTINFO 1 |
180 | #define __UAPI_DEF_IP6_MTUINFO 1 | |
cfd280c9 | 181 | |
ea1a8217 SH |
182 | /* Definitions for xattr.h */ |
183 | #define __UAPI_DEF_XATTR 1 | |
184 | ||
cfd280c9 CD |
185 | #endif /* __GLIBC__ */ |
186 | ||
187 | #endif /* _UAPI_LIBC_COMPAT_H */ |