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