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Christopher Ferrise0845012014-07-09 14:58:51 -07001/*
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
Christopher Ferris59ac31a2016-05-19 12:25:22 -070054/* 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
Christopher Ferrise0845012014-07-09 14:58:51 -070088/* 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. */
Christopher Ferris12e1f282016-02-04 12:35:07 -080093#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
Christopher Ferrise0845012014-07-09 14:58:51 -0700100#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
Christopher Ferris67b3b9d2015-03-31 11:49:56 -0700113#define __UAPI_DEF_IPV6_OPTIONS 0
Christopher Ferris12e1f282016-02-04 12:35:07 -0800114#define __UAPI_DEF_IN6_PKTINFO 0
115#define __UAPI_DEF_IP6_MTUINFO 0
Christopher Ferrise0845012014-07-09 14:58:51 -0700116
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. */
Christopher Ferris12e1f282016-02-04 12:35:07 -0800122#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
Christopher Ferrise0845012014-07-09 14:58:51 -0700129#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
Christopher Ferris67b3b9d2015-03-31 11:49:56 -0700136#define __UAPI_DEF_IPV6_OPTIONS 1
Christopher Ferris12e1f282016-02-04 12:35:07 -0800137#define __UAPI_DEF_IN6_PKTINFO 1
138#define __UAPI_DEF_IP6_MTUINFO 1
Christopher Ferrise0845012014-07-09 14:58:51 -0700139
140#endif /* _NETINET_IN_H */
141
Christopher Ferris31475242014-09-02 17:43:51 -0700142/* 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
Christopher Ferrise0845012014-07-09 14:58:51 -0700148
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
Christopher Ferris59ac31a2016-05-19 12:25:22 -0700154/* 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
Christopher Ferris12e1f282016-02-04 12:35:07 -0800164/* 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
Christopher Ferrise0845012014-07-09 14:58:51 -0700172/* 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
Christopher Ferris67b3b9d2015-03-31 11:49:56 -0700178#define __UAPI_DEF_IPV6_OPTIONS 1
Christopher Ferris12e1f282016-02-04 12:35:07 -0800179#define __UAPI_DEF_IN6_PKTINFO 1
180#define __UAPI_DEF_IP6_MTUINFO 1
Christopher Ferrise0845012014-07-09 14:58:51 -0700181
Christopher Ferris31475242014-09-02 17:43:51 -0700182/* Definitions for xattr.h */
183#define __UAPI_DEF_XATTR 1
184
Christopher Ferrise0845012014-07-09 14:58:51 -0700185#endif /* __GLIBC__ */
186
187#endif /* _UAPI_LIBC_COMPAT_H */