1 From c6bdd0d302119819de72439972d0462c26ef9eda Mon Sep 17 00:00:00 2001
2 From: Felix Janda <felix.janda@posteo.de>
3 Date: Sun, 12 Nov 2017 13:30:17 -0500
4 Subject: uapi libc compat: add fallback for unsupported libcs
6 libc-compat.h aims to prevent symbol collisions between uapi and libc
7 headers for each supported libc. This requires continuous coordination
10 The goal of this commit is to improve the situation for libcs (such as
11 musl) which are not yet supported and/or do not wish to be explicitly
12 supported, while not affecting supported libcs. More precisely, with
13 this commit, unsupported libcs can request the suppression of any
14 specific uapi definition by defining the correspondings _UAPI_DEF_*
15 macro as 0. This can fix symbol collisions for them, as long as the
16 libc headers are included before the uapi headers. Inclusion in the
17 other order is outside the scope of this commit.
19 All infrastructure in order to enable this fallback for unsupported
20 libcs is already in place, except that libc-compat.h unconditionally
21 defines all _UAPI_DEF_* macros to 1 for all unsupported libcs so that
22 any previous definitions are ignored. In order to fix this, this commit
23 merely makes these definitions conditional.
25 This commit together with the musl libc commit
27 http://git.musl-libc.org/cgit/musl/commit/?id=04983f2272382af92eb8f8838964ff944fbb8258
29 fixes for example the following compiler errors when <linux/in6.h> is
30 included after musl's <netinet/in.h>:
32 ./linux/in6.h:32:8: error: redefinition of 'struct in6_addr'
33 ./linux/in6.h:49:8: error: redefinition of 'struct sockaddr_in6'
34 ./linux/in6.h:59:8: error: redefinition of 'struct ipv6_mreq'
36 The comments referencing glibc are still correct, but this file is not
37 only used for glibc any more.
39 Signed-off-by: Felix Janda <felix.janda@posteo.de>
40 Reviewed-by: Hauke Mehrtens <hauke@hauke-m.de>
42 include/uapi/linux/libc-compat.h | 55 +++++++++++++++++++++++++++++++++++++++-
43 1 file changed, 54 insertions(+), 1 deletion(-)
45 --- a/include/uapi/linux/libc-compat.h
46 +++ b/include/uapi/linux/libc-compat.h
49 /* If we did not see any headers from any supported C libraries,
50 * or we are being included in the kernel, then define everything
52 + * that we need. Check for previous __UAPI_* definitions to give
53 + * unsupported C libraries a way to opt out of any kernel definition. */
54 #else /* !defined(__GLIBC__) */
56 /* Definitions for in.h */
57 +#ifndef __UAPI_DEF_IN_ADDR
58 #define __UAPI_DEF_IN_ADDR 1
60 +#ifndef __UAPI_DEF_IN_IPPROTO
61 #define __UAPI_DEF_IN_IPPROTO 1
63 +#ifndef __UAPI_DEF_IN_PKTINFO
64 #define __UAPI_DEF_IN_PKTINFO 1
66 +#ifndef __UAPI_DEF_IP_MREQ
67 #define __UAPI_DEF_IP_MREQ 1
69 +#ifndef __UAPI_DEF_SOCKADDR_IN
70 #define __UAPI_DEF_SOCKADDR_IN 1
72 +#ifndef __UAPI_DEF_IN_CLASS
73 #define __UAPI_DEF_IN_CLASS 1
76 /* Definitions for in6.h */
77 +#ifndef __UAPI_DEF_IN6_ADDR
78 #define __UAPI_DEF_IN6_ADDR 1
80 +#ifndef __UAPI_DEF_IN6_ADDR_ALT
81 #define __UAPI_DEF_IN6_ADDR_ALT 1
83 +#ifndef __UAPI_DEF_SOCKADDR_IN6
84 #define __UAPI_DEF_SOCKADDR_IN6 1
86 +#ifndef __UAPI_DEF_IPV6_MREQ
87 #define __UAPI_DEF_IPV6_MREQ 1
89 +#ifndef __UAPI_DEF_IPPROTO_V6
90 #define __UAPI_DEF_IPPROTO_V6 1
92 +#ifndef __UAPI_DEF_IPV6_OPTIONS
93 #define __UAPI_DEF_IPV6_OPTIONS 1
96 /* Definitions for xattr.h */
97 +#ifndef __UAPI_DEF_XATTR
98 #define __UAPI_DEF_XATTR 1
101 #endif /* __GLIBC__ */