[mirror_iproute2.git] / include / uapi / linux / libc-compat.h

/* 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. */
#else /* !defined(__GLIBC__) */

/* Definitions for if.h */
#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

/* Definitions for in.h */
#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

/* 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 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

/* Definitions for xattr.h */
#define __UAPI_DEF_XATTR		1

#endif /* __GLIBC__ */

#endif /* _LIBC_COMPAT_H */
Commit	Line	Data
ba914908	1	/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
5a311b0b SH	2	/*
	3	* Compatibility interface for userspace libc header coordination:
	4	*
	5	* Define compatibility macros that are used to control the inclusion or
	6	* exclusion of UAPI structures and definitions in coordination with another
	7	* userspace C library.
	8	*
	9	* This header is intended to solve the problem of UAPI definitions that
	10	* conflict with userspace definitions. If a UAPI header has such conflicting
	11	* definitions then the solution is as follows:
	12	*
	13	* * Synchronize the UAPI header and the libc headers so either one can be
	14	* used and such that the ABI is preserved. If this is not possible then
	15	* no simple compatibility interface exists (you need to write translating
	16	* wrappers and rename things) and you can't use this interface.
	17	*
	18	* Then follow this process:
	19	*
	20	* (a) Include libc-compat.h in the UAPI header.
	21	* e.g. #include <linux/libc-compat.h>
	22	* This include must be as early as possible.
	23	*
	24	* (b) In libc-compat.h add enough code to detect that the comflicting
	25	* userspace libc header has been included first.
	26	*
	27	* (c) If the userspace libc header has been included first define a set of
	28	* guard macros of the form __UAPI_DEF_FOO and set their values to 1, else
	29	* set their values to 0.
	30	*
	31	* (d) Back in the UAPI header with the conflicting definitions, guard the
	32	* definitions with:
	33	* #if __UAPI_DEF_FOO
	34	* ...
	35	* #endif
	36	*
	37	* This fixes the situation where the linux headers are included after the
	38	* libc headers. To fix the problem with the inclusion in the other order the
	39	* userspace libc headers must be fixed like this:
	40	*
	41	* * For all definitions that conflict with kernel definitions wrap those
	42	* defines in the following:
	43	* #if !__UAPI_DEF_FOO
	44	* ...
	45	* #endif
	46	*
	47	* This prevents the redefinition of a construct already defined by the kernel.
	48	*/
	49	#ifndef _LIBC_COMPAT_H
	50	#define _LIBC_COMPAT_H
	51
	52	/* We have included glibc headers... */
	53	#if defined(__GLIBC__)
	54
8a781d7e	55	/* Coordinate with glibc net/if.h header. */
0a99e7ba	56	#if defined(_NET_IF_H) && defined(__USE_MISC)
8a781d7e SH	57
	58	/* GLIBC headers included first so don't define anything
	59	* that would already be defined. */
	60
	61	#define __UAPI_DEF_IF_IFCONF 0
	62	#define __UAPI_DEF_IF_IFMAP 0
	63	#define __UAPI_DEF_IF_IFNAMSIZ 0
	64	#define __UAPI_DEF_IF_IFREQ 0
	65	/* Everything up to IFF_DYNAMIC, matches net/if.h until glibc 2.23 */
	66	#define __UAPI_DEF_IF_NET_DEVICE_FLAGS 0
	67	/* For the future if glibc adds IFF_LOWER_UP, IFF_DORMANT and IFF_ECHO */
	68	#ifndef __UAPI_DEF_IF_NET_DEVICE_FLAGS_LOWER_UP_DORMANT_ECHO
	69	#define __UAPI_DEF_IF_NET_DEVICE_FLAGS_LOWER_UP_DORMANT_ECHO 1
	70	#endif /* __UAPI_DEF_IF_NET_DEVICE_FLAGS_LOWER_UP_DORMANT_ECHO */
	71
	72	#else /* _NET_IF_H */
	73
	74	/* Linux headers included first, and we must define everything
	75	* we need. The expectation is that glibc will check the
	76	* __UAPI_DEF_* defines and adjust appropriately. */
	77
	78	#define __UAPI_DEF_IF_IFCONF 1
	79	#define __UAPI_DEF_IF_IFMAP 1
	80	#define __UAPI_DEF_IF_IFNAMSIZ 1
	81	#define __UAPI_DEF_IF_IFREQ 1
	82	/* Everything up to IFF_DYNAMIC, matches net/if.h until glibc 2.23 */
	83	#define __UAPI_DEF_IF_NET_DEVICE_FLAGS 1
	84	/* For the future if glibc adds IFF_LOWER_UP, IFF_DORMANT and IFF_ECHO */
	85	#define __UAPI_DEF_IF_NET_DEVICE_FLAGS_LOWER_UP_DORMANT_ECHO 1
	86
	87	#endif /* _NET_IF_H */
	88
5a311b0b SH	89	/* Coordinate with glibc netinet/in.h header. */
	90	#if defined(_NETINET_IN_H)
	91
	92	/* GLIBC headers included first so don't define anything
	93	* that would already be defined. */
ff631c3a SH	94	#define __UAPI_DEF_IN_ADDR 0
	95	#define __UAPI_DEF_IN_IPPROTO 0
	96	#define __UAPI_DEF_IN_PKTINFO 0
	97	#define __UAPI_DEF_IP_MREQ 0
	98	#define __UAPI_DEF_SOCKADDR_IN 0
	99	#define __UAPI_DEF_IN_CLASS 0
	100
5a311b0b SH	101	#define __UAPI_DEF_IN6_ADDR 0
	102	/* The exception is the in6_addr macros which must be defined
	103	* if the glibc code didn't define them. This guard matches
	104	* the guard in glibc/inet/netinet/in.h which defines the
	105	* additional in6_addr macros e.g. s6_addr16, and s6_addr32. */
	106	#if defined(__USE_MISC) \|\| defined (__USE_GNU)
	107	#define __UAPI_DEF_IN6_ADDR_ALT 0
	108	#else
	109	#define __UAPI_DEF_IN6_ADDR_ALT 1
	110	#endif
	111	#define __UAPI_DEF_SOCKADDR_IN6 0
	112	#define __UAPI_DEF_IPV6_MREQ 0
	113	#define __UAPI_DEF_IPPROTO_V6 0
8a504fc3	114	#define __UAPI_DEF_IPV6_OPTIONS 0
f233410d SH	115	#define __UAPI_DEF_IN6_PKTINFO 0
f233410d SH	116	#define __UAPI_DEF_IP6_MTUINFO 0
5a311b0b SH	117
	118	#else
	119
	120	/* Linux headers included first, and we must define everything
	121	* we need. The expectation is that glibc will check the
	122	* __UAPI_DEF_* defines and adjust appropriately. */
ff631c3a SH	123	#define __UAPI_DEF_IN_ADDR 1
	124	#define __UAPI_DEF_IN_IPPROTO 1
	125	#define __UAPI_DEF_IN_PKTINFO 1
	126	#define __UAPI_DEF_IP_MREQ 1
	127	#define __UAPI_DEF_SOCKADDR_IN 1
	128	#define __UAPI_DEF_IN_CLASS 1
	129
5a311b0b SH	130	#define __UAPI_DEF_IN6_ADDR 1
	131	/* We unconditionally define the in6_addr macros and glibc must
	132	* coordinate. */
	133	#define __UAPI_DEF_IN6_ADDR_ALT 1
	134	#define __UAPI_DEF_SOCKADDR_IN6 1
	135	#define __UAPI_DEF_IPV6_MREQ 1
	136	#define __UAPI_DEF_IPPROTO_V6 1
8a504fc3	137	#define __UAPI_DEF_IPV6_OPTIONS 1
f233410d SH	138	#define __UAPI_DEF_IN6_PKTINFO 1
f233410d SH	139	#define __UAPI_DEF_IP6_MTUINFO 1
5a311b0b SH	140
	141	#endif /* _NETINET_IN_H */
	142
3cad6e5f SH	143	/* Coordinate with glibc netipx/ipx.h header. */
	144	#if defined(__NETIPX_IPX_H)
	145
	146	#define __UAPI_DEF_SOCKADDR_IPX 0
	147	#define __UAPI_DEF_IPX_ROUTE_DEFINITION 0
	148	#define __UAPI_DEF_IPX_INTERFACE_DEFINITION 0
	149	#define __UAPI_DEF_IPX_CONFIG_DATA 0
	150	#define __UAPI_DEF_IPX_ROUTE_DEF 0
	151
	152	#else /* defined(__NETIPX_IPX_H) */
	153
	154	#define __UAPI_DEF_SOCKADDR_IPX 1
	155	#define __UAPI_DEF_IPX_ROUTE_DEFINITION 1
	156	#define __UAPI_DEF_IPX_INTERFACE_DEFINITION 1
	157	#define __UAPI_DEF_IPX_CONFIG_DATA 1
	158	#define __UAPI_DEF_IPX_ROUTE_DEF 1
	159
	160	#endif /* defined(__NETIPX_IPX_H) */
	161
5a311b0b SH	162	/* Definitions for xattr.h */
	163	#if defined(_SYS_XATTR_H)
	164	#define __UAPI_DEF_XATTR 0
	165	#else
	166	#define __UAPI_DEF_XATTR 1
	167	#endif
	168
	169	/* If we did not see any headers from any supported C libraries,
	170	* or we are being included in the kernel, then define everything
	171	* that we need. */
	172	#else /* !defined(__GLIBC__) */
	173
8a781d7e SH	174	/* Definitions for if.h */
	175	#define __UAPI_DEF_IF_IFCONF 1
	176	#define __UAPI_DEF_IF_IFMAP 1
	177	#define __UAPI_DEF_IF_IFNAMSIZ 1
	178	#define __UAPI_DEF_IF_IFREQ 1
	179	/* Everything up to IFF_DYNAMIC, matches net/if.h until glibc 2.23 */
	180	#define __UAPI_DEF_IF_NET_DEVICE_FLAGS 1
	181	/* For the future if glibc adds IFF_LOWER_UP, IFF_DORMANT and IFF_ECHO */
	182	#define __UAPI_DEF_IF_NET_DEVICE_FLAGS_LOWER_UP_DORMANT_ECHO 1
	183
f5386e11 SH	184	/* Definitions for in.h */
	185	#define __UAPI_DEF_IN_ADDR 1
	186	#define __UAPI_DEF_IN_IPPROTO 1
	187	#define __UAPI_DEF_IN_PKTINFO 1
	188	#define __UAPI_DEF_IP_MREQ 1
	189	#define __UAPI_DEF_SOCKADDR_IN 1
	190	#define __UAPI_DEF_IN_CLASS 1
	191
5a311b0b SH	192	/* Definitions for in6.h */
	193	#define __UAPI_DEF_IN6_ADDR 1
	194	#define __UAPI_DEF_IN6_ADDR_ALT 1
	195	#define __UAPI_DEF_SOCKADDR_IN6 1
	196	#define __UAPI_DEF_IPV6_MREQ 1
	197	#define __UAPI_DEF_IPPROTO_V6 1
8a504fc3	198	#define __UAPI_DEF_IPV6_OPTIONS 1
f233410d SH	199	#define __UAPI_DEF_IN6_PKTINFO 1
f233410d SH	200	#define __UAPI_DEF_IP6_MTUINFO 1
5a311b0b	201
3cad6e5f SH	202	/* Definitions for ipx.h */
	203	#define __UAPI_DEF_SOCKADDR_IPX 1
	204	#define __UAPI_DEF_IPX_ROUTE_DEFINITION 1
	205	#define __UAPI_DEF_IPX_INTERFACE_DEFINITION 1
	206	#define __UAPI_DEF_IPX_CONFIG_DATA 1
	207	#define __UAPI_DEF_IPX_ROUTE_DEF 1
	208
5a311b0b SH	209	/* Definitions for xattr.h */
	210	#define __UAPI_DEF_XATTR 1
	211
	212	#endif /* __GLIBC__ */
	213
	214	#endif /* _LIBC_COMPAT_H */