/* 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 _LIBC_COMPAT_H

#define _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 /* _LIBC_COMPAT_H */