target/linux/generic/backport-4.9/270-uapi-libc-compat-add-fallback-for-unsupported-libcs.patch

   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
   5
   6 libc-compat.h aims to prevent symbol collisions between uapi and libc
   7 headers for each supported libc. This requires continuous coordination
   8 between them.
   9
  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.
  18
  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.
  24
  25 This commit together with the musl libc commit
  26
  27 http://git.musl-libc.org/cgit/musl/commit/?id=04983f2272382af92eb8f8838964ff944fbb8258
  28
  29 fixes for example the following compiler errors when <linux/in6.h> is
  30 included after musl's <netinet/in.h>:
  31
  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'
  35
  36 The comments referencing glibc are still correct, but this file is not
  37 only used for glibc any more.
  38
  39 Signed-off-by: Felix Janda <felix.janda@posteo.de>
  40 Reviewed-by: Hauke Mehrtens <hauke@hauke-m.de>
  41 ---
  42  include/uapi/linux/libc-compat.h | 55 +++++++++++++++++++++++++++++++++++++++-
  43  1 file changed, 54 insertions(+), 1 deletion(-)
  44
  45 --- a/include/uapi/linux/libc-compat.h
  46 +++ b/include/uapi/linux/libc-compat.h
  47 @@ -167,46 +167,99 @@
  48
  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
  51 - * that we need. */
  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__) */
  55
  56  /* Definitions for if.h */
  57 +#ifndef __UAPI_DEF_IF_IFCONF
  58  #define __UAPI_DEF_IF_IFCONF 1
  59 +#endif
  60 +#ifndef __UAPI_DEF_IF_IFMAP
  61  #define __UAPI_DEF_IF_IFMAP 1
  62 +#endif
  63 +#ifndef __UAPI_DEF_IF_IFNAMSIZ
  64  #define __UAPI_DEF_IF_IFNAMSIZ 1
  65 +#endif
  66 +#ifndef __UAPI_DEF_IF_IFREQ
  67  #define __UAPI_DEF_IF_IFREQ 1
  68 +#endif
  69  /* Everything up to IFF_DYNAMIC, matches net/if.h until glibc 2.23 */
  70 +#ifndef __UAPI_DEF_IF_NET_DEVICE_FLAGS
  71  #define __UAPI_DEF_IF_NET_DEVICE_FLAGS 1
  72 +#endif
  73  /* For the future if glibc adds IFF_LOWER_UP, IFF_DORMANT and IFF_ECHO */
  74 +#ifndef __UAPI_DEF_IF_NET_DEVICE_FLAGS_LOWER_UP_DORMANT_ECHO
  75  #define __UAPI_DEF_IF_NET_DEVICE_FLAGS_LOWER_UP_DORMANT_ECHO 1
  76 +#endif
  77
  78  /* Definitions for in.h */
  79 +#ifndef __UAPI_DEF_IN_ADDR
  80  #define __UAPI_DEF_IN_ADDR             1
  81 +#endif
  82 +#ifndef __UAPI_DEF_IN_IPPROTO
  83  #define __UAPI_DEF_IN_IPPROTO          1
  84 +#endif
  85 +#ifndef __UAPI_DEF_IN_PKTINFO
  86  #define __UAPI_DEF_IN_PKTINFO          1
  87 +#endif
  88 +#ifndef __UAPI_DEF_IP_MREQ
  89  #define __UAPI_DEF_IP_MREQ             1
  90 +#endif
  91 +#ifndef __UAPI_DEF_SOCKADDR_IN
  92  #define __UAPI_DEF_SOCKADDR_IN         1
  93 +#endif
  94 +#ifndef __UAPI_DEF_IN_CLASS
  95  #define __UAPI_DEF_IN_CLASS            1
  96 +#endif
  97
  98  /* Definitions for in6.h */
  99 +#ifndef __UAPI_DEF_IN6_ADDR
 100  #define __UAPI_DEF_IN6_ADDR            1
 101 +#endif
 102 +#ifndef __UAPI_DEF_IN6_ADDR_ALT
 103  #define __UAPI_DEF_IN6_ADDR_ALT                1
 104 +#endif
 105 +#ifndef __UAPI_DEF_SOCKADDR_IN6
 106  #define __UAPI_DEF_SOCKADDR_IN6                1
 107 +#endif
 108 +#ifndef __UAPI_DEF_IPV6_MREQ
 109  #define __UAPI_DEF_IPV6_MREQ           1
 110 +#endif
 111 +#ifndef __UAPI_DEF_IPPROTO_V6
 112  #define __UAPI_DEF_IPPROTO_V6          1
 113 +#endif
 114 +#ifndef __UAPI_DEF_IPV6_OPTIONS
 115  #define __UAPI_DEF_IPV6_OPTIONS                1
 116 +#endif
 117 +#ifndef __UAPI_DEF_IN6_PKTINFO
 118  #define __UAPI_DEF_IN6_PKTINFO         1
 119 +#endif
 120 +#ifndef __UAPI_DEF_IP6_MTUINFO
 121  #define __UAPI_DEF_IP6_MTUINFO         1
 122 +#endif
 123
 124  /* Definitions for ipx.h */
 125 +#ifndef __UAPI_DEF_SOCKADDR_IPX
 126  #define __UAPI_DEF_SOCKADDR_IPX                        1
 127 +#endif
 128 +#ifndef __UAPI_DEF_IPX_ROUTE_DEFINITION
 129  #define __UAPI_DEF_IPX_ROUTE_DEFINITION                1
 130 +#endif
 131 +#ifndef __UAPI_DEF_IPX_INTERFACE_DEFINITION
 132  #define __UAPI_DEF_IPX_INTERFACE_DEFINITION    1
 133 +#endif
 134 +#ifndef __UAPI_DEF_IPX_CONFIG_DATA
 135  #define __UAPI_DEF_IPX_CONFIG_DATA             1
 136 +#endif
 137 +#ifndef __UAPI_DEF_IPX_ROUTE_DEF
 138  #define __UAPI_DEF_IPX_ROUTE_DEF               1
 139 +#endif
 140
 141  /* Definitions for xattr.h */
 142 +#ifndef __UAPI_DEF_XATTR
 143  #define __UAPI_DEF_XATTR               1
 144 +#endif
 145
 146  #endif /* __GLIBC__ */
 147