diff options
Diffstat (limited to 'include/linux/libc-compat.h')
| -rw-r--r-- | include/linux/libc-compat.h | 267 |
1 files changed, 267 insertions, 0 deletions
diff --git a/include/linux/libc-compat.h b/include/linux/libc-compat.h new file mode 100644 index 000000000..8254c937c --- /dev/null +++ b/include/linux/libc-compat.h @@ -0,0 +1,267 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ +/* + * 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 _UAPI_LIBC_COMPAT_H +#define _UAPI_LIBC_COMPAT_H + +/* We have included glibc headers... */ +#if defined(__GLIBC__) + +/* Coordinate with glibc net/if.h header. */ +#if defined(_NET_IF_H) && defined(__USE_MISC) + +/* GLIBC headers included first so don't define anything + * that would already be defined. */ + +#define __UAPI_DEF_IF_IFCONF 0 +#define __UAPI_DEF_IF_IFMAP 0 +#define __UAPI_DEF_IF_IFNAMSIZ 0 +#define __UAPI_DEF_IF_IFREQ 0 +/* Everything up to IFF_DYNAMIC, matches net/if.h until glibc 2.23 */ +#define __UAPI_DEF_IF_NET_DEVICE_FLAGS 0 +/* For the future if glibc adds IFF_LOWER_UP, IFF_DORMANT and IFF_ECHO */ +#ifndef __UAPI_DEF_IF_NET_DEVICE_FLAGS_LOWER_UP_DORMANT_ECHO +#define __UAPI_DEF_IF_NET_DEVICE_FLAGS_LOWER_UP_DORMANT_ECHO 1 +#endif /* __UAPI_DEF_IF_NET_DEVICE_FLAGS_LOWER_UP_DORMANT_ECHO */ + +#else /* _NET_IF_H */ + +/* 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_IF_IFCONF 1 +#define __UAPI_DEF_IF_IFMAP 1 +#define __UAPI_DEF_IF_IFNAMSIZ 1 +#define __UAPI_DEF_IF_IFREQ 1 +/* Everything up to IFF_DYNAMIC, matches net/if.h until glibc 2.23 */ +#define __UAPI_DEF_IF_NET_DEVICE_FLAGS 1 +/* For the future if glibc adds IFF_LOWER_UP, IFF_DORMANT and IFF_ECHO */ +#define __UAPI_DEF_IF_NET_DEVICE_FLAGS_LOWER_UP_DORMANT_ECHO 1 + +#endif /* _NET_IF_H */ + +/* 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_IN_ADDR 0 +#define __UAPI_DEF_IN_IPPROTO 0 +#define __UAPI_DEF_IN_PKTINFO 0 +#define __UAPI_DEF_IP_MREQ 0 +#define __UAPI_DEF_SOCKADDR_IN 0 +#define __UAPI_DEF_IN_CLASS 0 + +#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_IN_ADDR 1 +#define __UAPI_DEF_IN_IPPROTO 1 +#define __UAPI_DEF_IN_PKTINFO 1 +#define __UAPI_DEF_IP_MREQ 1 +#define __UAPI_DEF_SOCKADDR_IN 1 +#define __UAPI_DEF_IN_CLASS 1 + +#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 */ + +/* Coordinate with glibc netipx/ipx.h header. */ +#if defined(__NETIPX_IPX_H) + +#define __UAPI_DEF_SOCKADDR_IPX 0 +#define __UAPI_DEF_IPX_ROUTE_DEFINITION 0 +#define __UAPI_DEF_IPX_INTERFACE_DEFINITION 0 +#define __UAPI_DEF_IPX_CONFIG_DATA 0 +#define __UAPI_DEF_IPX_ROUTE_DEF 0 + +#else /* defined(__NETIPX_IPX_H) */ + +#define __UAPI_DEF_SOCKADDR_IPX 1 +#define __UAPI_DEF_IPX_ROUTE_DEFINITION 1 +#define __UAPI_DEF_IPX_INTERFACE_DEFINITION 1 +#define __UAPI_DEF_IPX_CONFIG_DATA 1 +#define __UAPI_DEF_IPX_ROUTE_DEF 1 + +#endif /* defined(__NETIPX_IPX_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. Check for previous __UAPI_* definitions to give + * unsupported C libraries a way to opt out of any kernel definition. */ +#else /* !defined(__GLIBC__) */ + +/* Definitions for if.h */ +#ifndef __UAPI_DEF_IF_IFCONF +#define __UAPI_DEF_IF_IFCONF 1 +#endif +#ifndef __UAPI_DEF_IF_IFMAP +#define __UAPI_DEF_IF_IFMAP 1 +#endif +#ifndef __UAPI_DEF_IF_IFNAMSIZ +#define __UAPI_DEF_IF_IFNAMSIZ 1 +#endif +#ifndef __UAPI_DEF_IF_IFREQ +#define __UAPI_DEF_IF_IFREQ 1 +#endif +/* Everything up to IFF_DYNAMIC, matches net/if.h until glibc 2.23 */ +#ifndef __UAPI_DEF_IF_NET_DEVICE_FLAGS +#define __UAPI_DEF_IF_NET_DEVICE_FLAGS 1 +#endif +/* For the future if glibc adds IFF_LOWER_UP, IFF_DORMANT and IFF_ECHO */ +#ifndef __UAPI_DEF_IF_NET_DEVICE_FLAGS_LOWER_UP_DORMANT_ECHO +#define __UAPI_DEF_IF_NET_DEVICE_FLAGS_LOWER_UP_DORMANT_ECHO 1 +#endif + +/* Definitions for in.h */ +#ifndef __UAPI_DEF_IN_ADDR +#define __UAPI_DEF_IN_ADDR 1 +#endif +#ifndef __UAPI_DEF_IN_IPPROTO +#define __UAPI_DEF_IN_IPPROTO 1 +#endif +#ifndef __UAPI_DEF_IN_PKTINFO +#define __UAPI_DEF_IN_PKTINFO 1 +#endif +#ifndef __UAPI_DEF_IP_MREQ +#define __UAPI_DEF_IP_MREQ 1 +#endif +#ifndef __UAPI_DEF_SOCKADDR_IN +#define __UAPI_DEF_SOCKADDR_IN 1 +#endif +#ifndef __UAPI_DEF_IN_CLASS +#define __UAPI_DEF_IN_CLASS 1 +#endif + +/* Definitions for in6.h */ +#ifndef __UAPI_DEF_IN6_ADDR +#define __UAPI_DEF_IN6_ADDR 1 +#endif +#ifndef __UAPI_DEF_IN6_ADDR_ALT +#define __UAPI_DEF_IN6_ADDR_ALT 1 +#endif +#ifndef __UAPI_DEF_SOCKADDR_IN6 +#define __UAPI_DEF_SOCKADDR_IN6 1 +#endif +#ifndef __UAPI_DEF_IPV6_MREQ +#define __UAPI_DEF_IPV6_MREQ 1 +#endif +#ifndef __UAPI_DEF_IPPROTO_V6 +#define __UAPI_DEF_IPPROTO_V6 1 +#endif +#ifndef __UAPI_DEF_IPV6_OPTIONS +#define __UAPI_DEF_IPV6_OPTIONS 1 +#endif +#ifndef __UAPI_DEF_IN6_PKTINFO +#define __UAPI_DEF_IN6_PKTINFO 1 +#endif +#ifndef __UAPI_DEF_IP6_MTUINFO +#define __UAPI_DEF_IP6_MTUINFO 1 +#endif + +/* Definitions for ipx.h */ +#ifndef __UAPI_DEF_SOCKADDR_IPX +#define __UAPI_DEF_SOCKADDR_IPX 1 +#endif +#ifndef __UAPI_DEF_IPX_ROUTE_DEFINITION +#define __UAPI_DEF_IPX_ROUTE_DEFINITION 1 +#endif +#ifndef __UAPI_DEF_IPX_INTERFACE_DEFINITION +#define __UAPI_DEF_IPX_INTERFACE_DEFINITION 1 +#endif +#ifndef __UAPI_DEF_IPX_CONFIG_DATA +#define __UAPI_DEF_IPX_CONFIG_DATA 1 +#endif +#ifndef __UAPI_DEF_IPX_ROUTE_DEF +#define __UAPI_DEF_IPX_ROUTE_DEF 1 +#endif + +/* Definitions for xattr.h */ +#ifndef __UAPI_DEF_XATTR +#define __UAPI_DEF_XATTR 1 +#endif + +#endif /* __GLIBC__ */ + +#endif /* _UAPI_LIBC_COMPAT_H */ |