| /* |
| * Compatibility interface for userspace libc header coordination: |
| * |
| * Define compatibility macros that are used to control the inclusion or |
| * exclusion of UAPI structures and definitions in coordination with another |
| * userspace C library. |
| * |
| * This header is intended to solve the problem of UAPI definitions that |
| * conflict with userspace definitions. If a UAPI header has such conflicting |
| * definitions then the solution is as follows: |
| * |
| * * Synchronize the UAPI header and the libc headers so either one can be |
| * used and such that the ABI is preserved. If this is not possible then |
| * no simple compatibility interface exists (you need to write translating |
| * wrappers and rename things) and you can't use this interface. |
| * |
| * Then follow this process: |
| * |
| * (a) Include libc-compat.h in the UAPI header. |
| * e.g. #include <linux/libc-compat.h> |
| * This include must be as early as possible. |
| * |
| * (b) In libc-compat.h add enough code to detect that the comflicting |
| * userspace libc header has been included first. |
| * |
| * (c) If the userspace libc header has been included first define a set of |
| * guard macros of the form __UAPI_DEF_FOO and set their values to 1, else |
| * set their values to 0. |
| * |
| * (d) Back in the UAPI header with the conflicting definitions, guard the |
| * definitions with: |
| * #if __UAPI_DEF_FOO |
| * ... |
| * #endif |
| * |
| * This fixes the situation where the linux headers are included *after* the |
| * libc headers. To fix the problem with the inclusion in the other order the |
| * userspace libc headers must be fixed like this: |
| * |
| * * For all definitions that conflict with kernel definitions wrap those |
| * defines in the following: |
| * #if !__UAPI_DEF_FOO |
| * ... |
| * #endif |
| * |
| * This prevents the redefinition of a construct already defined by the kernel. |
| */ |
| #ifndef _LIBC_COMPAT_H |
| #define _LIBC_COMPAT_H |
| |
| /* We have included glibc headers... */ |
| #if defined(__GLIBC__) |
| |
| /* Coordinate with glibc netinet/in.h header. */ |
| #if defined(_NETINET_IN_H) |
| |
| /* GLIBC headers included first so don't define anything |
| * that would already be defined. */ |
| #define __UAPI_DEF_IN6_ADDR 0 |
| /* The exception is the in6_addr macros which must be defined |
| * if the glibc code didn't define them. This guard matches |
| * the guard in glibc/inet/netinet/in.h which defines the |
| * additional in6_addr macros e.g. s6_addr16, and s6_addr32. */ |
| #if defined(__USE_MISC) || defined (__USE_GNU) |
| #define __UAPI_DEF_IN6_ADDR_ALT 0 |
| #else |
| #define __UAPI_DEF_IN6_ADDR_ALT 1 |
| #endif |
| #define __UAPI_DEF_SOCKADDR_IN6 0 |
| #define __UAPI_DEF_IPV6_MREQ 0 |
| #define __UAPI_DEF_IPPROTO_V6 0 |
| #define __UAPI_DEF_IPV6_OPTIONS 0 |
| #define __UAPI_DEF_IN6_PKTINFO 0 |
| #define __UAPI_DEF_IP6_MTUINFO 0 |
| |
| #else |
| |
| /* Linux headers included first, and we must define everything |
| * we need. The expectation is that glibc will check the |
| * __UAPI_DEF_* defines and adjust appropriately. */ |
| #define __UAPI_DEF_IN6_ADDR 1 |
| /* We unconditionally define the in6_addr macros and glibc must |
| * coordinate. */ |
| #define __UAPI_DEF_IN6_ADDR_ALT 1 |
| #define __UAPI_DEF_SOCKADDR_IN6 1 |
| #define __UAPI_DEF_IPV6_MREQ 1 |
| #define __UAPI_DEF_IPPROTO_V6 1 |
| #define __UAPI_DEF_IPV6_OPTIONS 1 |
| #define __UAPI_DEF_IN6_PKTINFO 1 |
| #define __UAPI_DEF_IP6_MTUINFO 1 |
| |
| #endif /* _NETINET_IN_H */ |
| |
| /* Definitions for xattr.h */ |
| #if defined(_SYS_XATTR_H) |
| #define __UAPI_DEF_XATTR 0 |
| #else |
| #define __UAPI_DEF_XATTR 1 |
| #endif |
| |
| /* If we did not see any headers from any supported C libraries, |
| * or we are being included in the kernel, then define everything |
| * that we need. */ |
| #else /* !defined(__GLIBC__) */ |
| |
| /* Definitions for in6.h */ |
| #define __UAPI_DEF_IN6_ADDR 1 |
| #define __UAPI_DEF_IN6_ADDR_ALT 1 |
| #define __UAPI_DEF_SOCKADDR_IN6 1 |
| #define __UAPI_DEF_IPV6_MREQ 1 |
| #define __UAPI_DEF_IPPROTO_V6 1 |
| #define __UAPI_DEF_IPV6_OPTIONS 1 |
| #define __UAPI_DEF_IN6_PKTINFO 1 |
| #define __UAPI_DEF_IP6_MTUINFO 1 |
| |
| /* Definitions for xattr.h */ |
| #define __UAPI_DEF_XATTR 1 |
| |
| #endif /* __GLIBC__ */ |
| |
| #endif /* _LIBC_COMPAT_H */ |
