kernel: improve uapi headers coexistence with musl

Make some network uapi headers detect if they are included after
not only glibc but also musl headers.

Signed-off-by: Jonas Gorski <jogo@openwrt.org>

SVN-Revision: 46161

1 files changed, 81 insertions, 0 deletions

diff --git a/target/linux/generic/patches-3.18/271-uapi-libc-compat.h-do-not-rely-on-__GLIBC__.patch b/target/linux/generic/patches-3.18/271-uapi-libc-compat.h-do-not-rely-on-__GLIBC__.patch
new file mode 100644
index 0000000..891299e
--- /dev/null
+++ b/target/linux/generic/patches-3.18/271-uapi-libc-compat.h-do-not-rely-on-__GLIBC__.patch
@@ -0,0 +1,81 @@
+From f972afc2509eebcb00d370256c55b112a3b5ffca Mon Sep 17 00:00:00 2001
+From: David Heidelberger <david.heidelberger@ixit.cz>
+Date: Mon, 29 Jun 2015 16:50:40 +0200
+Subject: [PATCH 2/3] uapi/libc-compat.h: do not rely on __GLIBC__
+
+Musl provides the same structs as glibc, but does not provide a define to
+allow its detection. Since the absence of __GLIBC__ also can mean that it
+is included from the kernel, change the __GLIBC__ detection to
+!__KERNEL__, which should always be true when included from userspace.
+
+Signed-off-by: John Spencer <maillist-linux@barfooze.de>
+Tested-by: David Heidelberger <david.heidelberger@ixit.cz>
+Signed-off-by: Jonas Gorski <jogo@openwrt.org>
+---
+ include/uapi/linux/libc-compat.h | 18 +++++++++---------
+ 1 file changed, 9 insertions(+), 9 deletions(-)
+
+--- a/include/uapi/linux/libc-compat.h
++++ b/include/uapi/linux/libc-compat.h
+@@ -48,13 +48,13 @@
+ #ifndef _UAPI_LIBC_COMPAT_H
+ #define _UAPI_LIBC_COMPAT_H
+ 
+-/* We have included glibc headers... */
+-#if defined(__GLIBC__)
++/* We have included libc headers... */
++#if !defined(__KERNEL__)
+ 
+-/* Coordinate with glibc netinet/in.h header. */
++/* Coordinate with libc netinet/in.h header. */
+ #if defined(_NETINET_IN_H)
+ 
+-/* GLIBC headers included first so don't define anything
++/* LIBC 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
+@@ -68,7 +68,7 @@
+  * 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)
++#if !defined(__GLIBC__) || defined(__USE_MISC) || defined (__USE_GNU)
+ #define __UAPI_DEF_IN6_ADDR_ALT		0
+ #else
+ #define __UAPI_DEF_IN6_ADDR_ALT		1
+@@ -81,7 +81,7 @@
+ #else
+ 
+ /* Linux headers included first, and we must define everything
+- * we need. The expectation is that glibc will check the
++ * we need. The expectation is that the libc will check the
+  * __UAPI_DEF_* defines and adjust appropriately. */
+ #define __UAPI_DEF_IN_ADDR		1
+ #define __UAPI_DEF_IN_IPPROTO		1
+@@ -91,7 +91,7 @@
+ #define __UAPI_DEF_IN_CLASS		1
+ 
+ #define __UAPI_DEF_IN6_ADDR		1
+-/* We unconditionally define the in6_addr macros and glibc must
++/* We unconditionally define the in6_addr macros and the libc must
+  * coordinate. */
+ #define __UAPI_DEF_IN6_ADDR_ALT		1
+ #define __UAPI_DEF_SOCKADDR_IN6		1
+@@ -111,7 +111,7 @@
+ /* 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__) */
++#else /* defined(__KERNEL__) */
+ 
+ /* Definitions for in.h */
+ #define __UAPI_DEF_IN_ADDR		1
+@@ -132,6 +132,6 @@
+ /* Definitions for xattr.h */
+ #define __UAPI_DEF_XATTR		1
+ 
+-#endif /* __GLIBC__ */
++#endif /* __KERNEL__ */
+ 
+ #endif /* _UAPI_LIBC_COMPAT_H */