| 1 | /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ |
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| 2 | /* |
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| 3 | * Compatibility interface for userspace libc header coordination: |
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| 4 | * |
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| 5 | * Define compatibility macros that are used to control the inclusion or |
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| 6 | * exclusion of UAPI structures and definitions in coordination with another |
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| 7 | * userspace C library. |
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| 8 | * |
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| 9 | * This header is intended to solve the problem of UAPI definitions that |
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| 10 | * conflict with userspace definitions. If a UAPI header has such conflicting |
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| 11 | * definitions then the solution is as follows: |
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| 12 | * |
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| 13 | * * Synchronize the UAPI header and the libc headers so either one can be |
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| 14 | * used and such that the ABI is preserved. If this is not possible then |
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| 15 | * no simple compatibility interface exists (you need to write translating |
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| 16 | * wrappers and rename things) and you can't use this interface. |
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| 17 | * |
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| 18 | * Then follow this process: |
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| 19 | * |
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| 20 | * (a) Include libc-compat.h in the UAPI header. |
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| 21 | * e.g. #include <linux/libc-compat.h> |
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| 22 | * This include must be as early as possible. |
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| 23 | * |
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| 24 | * (b) In libc-compat.h add enough code to detect that the comflicting |
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| 25 | * userspace libc header has been included first. |
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| 26 | * |
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| 27 | * (c) If the userspace libc header has been included first define a set of |
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| 28 | * guard macros of the form __UAPI_DEF_FOO and set their values to 1, else |
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| 29 | * set their values to 0. |
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| 30 | * |
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| 31 | * (d) Back in the UAPI header with the conflicting definitions, guard the |
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| 32 | * definitions with: |
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| 33 | * #if __UAPI_DEF_FOO |
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| 34 | * ... |
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| 35 | * #endif |
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| 36 | * |
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| 37 | * This fixes the situation where the linux headers are included *after* the |
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| 38 | * libc headers. To fix the problem with the inclusion in the other order the |
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| 39 | * userspace libc headers must be fixed like this: |
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| 40 | * |
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| 41 | * * For all definitions that conflict with kernel definitions wrap those |
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| 42 | * defines in the following: |
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| 43 | * #if !__UAPI_DEF_FOO |
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| 44 | * ... |
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| 45 | * #endif |
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| 46 | * |
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| 47 | * This prevents the redefinition of a construct already defined by the kernel. |
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| 48 | */ |
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| 49 | #ifndef _LIBC_COMPAT_H |
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| 50 | #define _LIBC_COMPAT_H |
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| 51 | |
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| 52 | /* We have included glibc headers... */ |
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| 53 | #if defined(__GLIBC__) |
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| 54 | |
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| 55 | /* Coordinate with glibc net/if.h header. */ |
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| 56 | #if defined(_NET_IF_H) && defined(__USE_MISC) |
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| 57 | |
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| 58 | /* GLIBC headers included first so don't define anything |
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| 59 | * that would already be defined. */ |
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| 60 | |
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| 61 | #define __UAPI_DEF_IF_IFCONF 0 |
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| 62 | #define __UAPI_DEF_IF_IFMAP 0 |
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| 63 | #define __UAPI_DEF_IF_IFNAMSIZ 0 |
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| 64 | #define __UAPI_DEF_IF_IFREQ 0 |
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| 65 | /* Everything up to IFF_DYNAMIC, matches net/if.h until glibc 2.23 */ |
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| 66 | #define __UAPI_DEF_IF_NET_DEVICE_FLAGS 0 |
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| 67 | /* For the future if glibc adds IFF_LOWER_UP, IFF_DORMANT and IFF_ECHO */ |
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| 68 | #ifndef __UAPI_DEF_IF_NET_DEVICE_FLAGS_LOWER_UP_DORMANT_ECHO |
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| 69 | #define __UAPI_DEF_IF_NET_DEVICE_FLAGS_LOWER_UP_DORMANT_ECHO 1 |
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| 70 | #endif /* __UAPI_DEF_IF_NET_DEVICE_FLAGS_LOWER_UP_DORMANT_ECHO */ |
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| 71 | |
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| 72 | #else /* _NET_IF_H */ |
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| 73 | |
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| 74 | /* Linux headers included first, and we must define everything |
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| 75 | * we need. The expectation is that glibc will check the |
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| 76 | * __UAPI_DEF_* defines and adjust appropriately. */ |
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| 77 | |
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| 78 | #define __UAPI_DEF_IF_IFCONF 1 |
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| 79 | #define __UAPI_DEF_IF_IFMAP 1 |
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| 80 | #define __UAPI_DEF_IF_IFNAMSIZ 1 |
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| 81 | #define __UAPI_DEF_IF_IFREQ 1 |
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| 82 | /* Everything up to IFF_DYNAMIC, matches net/if.h until glibc 2.23 */ |
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| 83 | #define __UAPI_DEF_IF_NET_DEVICE_FLAGS 1 |
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| 84 | /* For the future if glibc adds IFF_LOWER_UP, IFF_DORMANT and IFF_ECHO */ |
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| 85 | #define __UAPI_DEF_IF_NET_DEVICE_FLAGS_LOWER_UP_DORMANT_ECHO 1 |
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| 86 | |
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| 87 | #endif /* _NET_IF_H */ |
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| 88 | |
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| 89 | /* Coordinate with glibc netinet/in.h header. */ |
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| 90 | #if defined(_NETINET_IN_H) |
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| 91 | |
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| 92 | /* GLIBC headers included first so don't define anything |
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| 93 | * that would already be defined. */ |
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| 94 | #define __UAPI_DEF_IN_ADDR 0 |
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| 95 | #define __UAPI_DEF_IN_IPPROTO 0 |
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| 96 | #define __UAPI_DEF_IN_PKTINFO 0 |
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| 97 | #define __UAPI_DEF_IP_MREQ 0 |
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| 98 | #define __UAPI_DEF_SOCKADDR_IN 0 |
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| 99 | #define __UAPI_DEF_IN_CLASS 0 |
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| 100 | |
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| 101 | #define __UAPI_DEF_IN6_ADDR 0 |
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| 102 | /* The exception is the in6_addr macros which must be defined |
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| 103 | * if the glibc code didn't define them. This guard matches |
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| 104 | * the guard in glibc/inet/netinet/in.h which defines the |
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| 105 | * additional in6_addr macros e.g. s6_addr16, and s6_addr32. */ |
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| 106 | #if defined(__USE_MISC) || defined (__USE_GNU) |
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| 107 | #define __UAPI_DEF_IN6_ADDR_ALT 0 |
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| 108 | #else |
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| 109 | #define __UAPI_DEF_IN6_ADDR_ALT 1 |
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| 110 | #endif |
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| 111 | #define __UAPI_DEF_SOCKADDR_IN6 0 |
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| 112 | #define __UAPI_DEF_IPV6_MREQ 0 |
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| 113 | #define __UAPI_DEF_IPPROTO_V6 0 |
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| 114 | #define __UAPI_DEF_IPV6_OPTIONS 0 |
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| 115 | #define __UAPI_DEF_IN6_PKTINFO 0 |
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| 116 | #define __UAPI_DEF_IP6_MTUINFO 0 |
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| 117 | |
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| 118 | #else |
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| 119 | |
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| 120 | /* Linux headers included first, and we must define everything |
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| 121 | * we need. The expectation is that glibc will check the |
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| 122 | * __UAPI_DEF_* defines and adjust appropriately. */ |
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| 123 | #define __UAPI_DEF_IN_ADDR 1 |
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| 124 | #define __UAPI_DEF_IN_IPPROTO 1 |
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| 125 | #define __UAPI_DEF_IN_PKTINFO 1 |
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| 126 | #define __UAPI_DEF_IP_MREQ 1 |
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| 127 | #define __UAPI_DEF_SOCKADDR_IN 1 |
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| 128 | #define __UAPI_DEF_IN_CLASS 1 |
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| 129 | |
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| 130 | #define __UAPI_DEF_IN6_ADDR 1 |
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| 131 | /* We unconditionally define the in6_addr macros and glibc must |
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| 132 | * coordinate. */ |
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| 133 | #define __UAPI_DEF_IN6_ADDR_ALT 1 |
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| 134 | #define __UAPI_DEF_SOCKADDR_IN6 1 |
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| 135 | #define __UAPI_DEF_IPV6_MREQ 1 |
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| 136 | #define __UAPI_DEF_IPPROTO_V6 1 |
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| 137 | #define __UAPI_DEF_IPV6_OPTIONS 1 |
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| 138 | #define __UAPI_DEF_IN6_PKTINFO 1 |
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| 139 | #define __UAPI_DEF_IP6_MTUINFO 1 |
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| 140 | |
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| 141 | #endif /* _NETINET_IN_H */ |
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| 142 | |
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| 143 | /* Coordinate with glibc netipx/ipx.h header. */ |
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| 144 | #if defined(__NETIPX_IPX_H) |
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| 145 | |
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| 146 | #define __UAPI_DEF_SOCKADDR_IPX 0 |
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| 147 | #define __UAPI_DEF_IPX_ROUTE_DEFINITION 0 |
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| 148 | #define __UAPI_DEF_IPX_INTERFACE_DEFINITION 0 |
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| 149 | #define __UAPI_DEF_IPX_CONFIG_DATA 0 |
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| 150 | #define __UAPI_DEF_IPX_ROUTE_DEF 0 |
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| 151 | |
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| 152 | #else /* defined(__NETIPX_IPX_H) */ |
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| 153 | |
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| 154 | #define __UAPI_DEF_SOCKADDR_IPX 1 |
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| 155 | #define __UAPI_DEF_IPX_ROUTE_DEFINITION 1 |
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| 156 | #define __UAPI_DEF_IPX_INTERFACE_DEFINITION 1 |
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| 157 | #define __UAPI_DEF_IPX_CONFIG_DATA 1 |
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| 158 | #define __UAPI_DEF_IPX_ROUTE_DEF 1 |
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| 159 | |
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| 160 | #endif /* defined(__NETIPX_IPX_H) */ |
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| 161 | |
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| 162 | /* Definitions for xattr.h */ |
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| 163 | #if defined(_SYS_XATTR_H) |
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| 164 | #define __UAPI_DEF_XATTR 0 |
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| 165 | #else |
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| 166 | #define __UAPI_DEF_XATTR 1 |
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| 167 | #endif |
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| 168 | |
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| 169 | /* If we did not see any headers from any supported C libraries, |
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| 170 | * or we are being included in the kernel, then define everything |
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| 171 | * that we need. Check for previous __UAPI_* definitions to give |
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| 172 | * unsupported C libraries a way to opt out of any kernel definition. */ |
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| 173 | #else /* !defined(__GLIBC__) */ |
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| 174 | |
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| 175 | /* Definitions for if.h */ |
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| 176 | #ifndef __UAPI_DEF_IF_IFCONF |
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| 177 | #define __UAPI_DEF_IF_IFCONF 1 |
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| 178 | #endif |
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| 179 | #ifndef __UAPI_DEF_IF_IFMAP |
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| 180 | #define __UAPI_DEF_IF_IFMAP 1 |
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| 181 | #endif |
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| 182 | #ifndef __UAPI_DEF_IF_IFNAMSIZ |
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| 183 | #define __UAPI_DEF_IF_IFNAMSIZ 1 |
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| 184 | #endif |
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| 185 | #ifndef __UAPI_DEF_IF_IFREQ |
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| 186 | #define __UAPI_DEF_IF_IFREQ 1 |
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| 187 | #endif |
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| 188 | /* Everything up to IFF_DYNAMIC, matches net/if.h until glibc 2.23 */ |
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| 189 | #ifndef __UAPI_DEF_IF_NET_DEVICE_FLAGS |
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| 190 | #define __UAPI_DEF_IF_NET_DEVICE_FLAGS 1 |
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| 191 | #endif |
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| 192 | /* For the future if glibc adds IFF_LOWER_UP, IFF_DORMANT and IFF_ECHO */ |
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| 193 | #ifndef __UAPI_DEF_IF_NET_DEVICE_FLAGS_LOWER_UP_DORMANT_ECHO |
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| 194 | #define __UAPI_DEF_IF_NET_DEVICE_FLAGS_LOWER_UP_DORMANT_ECHO 1 |
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| 195 | #endif |
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| 196 | |
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| 197 | /* Definitions for in.h */ |
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| 198 | #ifndef __UAPI_DEF_IN_ADDR |
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| 199 | #define __UAPI_DEF_IN_ADDR 1 |
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| 200 | #endif |
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| 201 | #ifndef __UAPI_DEF_IN_IPPROTO |
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| 202 | #define __UAPI_DEF_IN_IPPROTO 1 |
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| 203 | #endif |
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| 204 | #ifndef __UAPI_DEF_IN_PKTINFO |
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| 205 | #define __UAPI_DEF_IN_PKTINFO 1 |
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| 206 | #endif |
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| 207 | #ifndef __UAPI_DEF_IP_MREQ |
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| 208 | #define __UAPI_DEF_IP_MREQ 1 |
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| 209 | #endif |
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| 210 | #ifndef __UAPI_DEF_SOCKADDR_IN |
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| 211 | #define __UAPI_DEF_SOCKADDR_IN 1 |
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| 212 | #endif |
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| 213 | #ifndef __UAPI_DEF_IN_CLASS |
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| 214 | #define __UAPI_DEF_IN_CLASS 1 |
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| 215 | #endif |
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| 216 | |
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| 217 | /* Definitions for in6.h */ |
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| 218 | #ifndef __UAPI_DEF_IN6_ADDR |
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| 219 | #define __UAPI_DEF_IN6_ADDR 1 |
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| 220 | #endif |
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| 221 | #ifndef __UAPI_DEF_IN6_ADDR_ALT |
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| 222 | #define __UAPI_DEF_IN6_ADDR_ALT 1 |
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| 223 | #endif |
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| 224 | #ifndef __UAPI_DEF_SOCKADDR_IN6 |
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| 225 | #define __UAPI_DEF_SOCKADDR_IN6 1 |
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| 226 | #endif |
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| 227 | #ifndef __UAPI_DEF_IPV6_MREQ |
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| 228 | #define __UAPI_DEF_IPV6_MREQ 1 |
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| 229 | #endif |
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| 230 | #ifndef __UAPI_DEF_IPPROTO_V6 |
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| 231 | #define __UAPI_DEF_IPPROTO_V6 1 |
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| 232 | #endif |
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| 233 | #ifndef __UAPI_DEF_IPV6_OPTIONS |
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| 234 | #define __UAPI_DEF_IPV6_OPTIONS 1 |
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| 235 | #endif |
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| 236 | #ifndef __UAPI_DEF_IN6_PKTINFO |
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| 237 | #define __UAPI_DEF_IN6_PKTINFO 1 |
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| 238 | #endif |
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| 239 | #ifndef __UAPI_DEF_IP6_MTUINFO |
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| 240 | #define __UAPI_DEF_IP6_MTUINFO 1 |
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| 241 | #endif |
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| 242 | |
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| 243 | /* Definitions for ipx.h */ |
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| 244 | #ifndef __UAPI_DEF_SOCKADDR_IPX |
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| 245 | #define __UAPI_DEF_SOCKADDR_IPX 1 |
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| 246 | #endif |
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| 247 | #ifndef __UAPI_DEF_IPX_ROUTE_DEFINITION |
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| 248 | #define __UAPI_DEF_IPX_ROUTE_DEFINITION 1 |
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| 249 | #endif |
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| 250 | #ifndef __UAPI_DEF_IPX_INTERFACE_DEFINITION |
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| 251 | #define __UAPI_DEF_IPX_INTERFACE_DEFINITION 1 |
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| 252 | #endif |
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| 253 | #ifndef __UAPI_DEF_IPX_CONFIG_DATA |
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| 254 | #define __UAPI_DEF_IPX_CONFIG_DATA 1 |
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| 255 | #endif |
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| 256 | #ifndef __UAPI_DEF_IPX_ROUTE_DEF |
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| 257 | #define __UAPI_DEF_IPX_ROUTE_DEF 1 |
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| 258 | #endif |
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| 259 | |
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| 260 | /* Definitions for xattr.h */ |
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| 261 | #ifndef __UAPI_DEF_XATTR |
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| 262 | #define __UAPI_DEF_XATTR 1 |
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| 263 | #endif |
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| 264 | |
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| 265 | #endif /* __GLIBC__ */ |
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| 266 | |
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| 267 | #endif /* _LIBC_COMPAT_H */ |
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| 268 | |
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