From 3df5e3bd1363a767c29637c97e686bb5485b9659 Mon Sep 17 00:00:00 2001
From: Wolfgang Thaller <wolfgang.thaller@gmx.net>
Date: Thu, 28 Sep 2017 00:33:38 +0200
Subject: [PATCH] libelf: portable endianness detection

---
 libelf/src/portable_endian.h | 119 +++++++++++++++++++++++++++++++++++
 libelf/src/system.h          |  20 ++----
 2 files changed, 124 insertions(+), 15 deletions(-)
 create mode 100644 libelf/src/portable_endian.h

diff --git a/libelf/src/portable_endian.h b/libelf/src/portable_endian.h
new file mode 100644
index 0000000000..55f8cc2525
--- /dev/null
+++ b/libelf/src/portable_endian.h
@@ -0,0 +1,119 @@
+// "License": Public Domain
+// I, Mathias Panzenböck, place this file hereby into the public domain. Use it at your own risk for whatever you like.
+// In case there are jurisdictions that don't support putting things in the public domain you can also consider it to
+// be "dual licensed" under the BSD, MIT and Apache licenses, if you want to. This code is trivial anyway. Consider it
+// an example on how to get the endian conversion functions on different platforms.
+
+#ifndef PORTABLE_ENDIAN_H__
+#define PORTABLE_ENDIAN_H__
+
+#if (defined(_WIN16) || defined(_WIN32) || defined(_WIN64)) && !defined(__WINDOWS__)
+
+#	define __WINDOWS__
+
+#endif
+
+#if defined(__linux__) || defined(__CYGWIN__)
+
+#	include <endian.h>
+
+#elif defined(__APPLE__)
+
+#	include <libkern/OSByteOrder.h>
+
+#	define htobe16(x) OSSwapHostToBigInt16(x)
+#	define htole16(x) OSSwapHostToLittleInt16(x)
+#	define be16toh(x) OSSwapBigToHostInt16(x)
+#	define le16toh(x) OSSwapLittleToHostInt16(x)
+ 
+#	define htobe32(x) OSSwapHostToBigInt32(x)
+#	define htole32(x) OSSwapHostToLittleInt32(x)
+#	define be32toh(x) OSSwapBigToHostInt32(x)
+#	define le32toh(x) OSSwapLittleToHostInt32(x)
+ 
+#	define htobe64(x) OSSwapHostToBigInt64(x)
+#	define htole64(x) OSSwapHostToLittleInt64(x)
+#	define be64toh(x) OSSwapBigToHostInt64(x)
+#	define le64toh(x) OSSwapLittleToHostInt64(x)
+
+#	define __BYTE_ORDER    BYTE_ORDER
+#	define __BIG_ENDIAN    BIG_ENDIAN
+#	define __LITTLE_ENDIAN LITTLE_ENDIAN
+#	define __PDP_ENDIAN    PDP_ENDIAN
+
+#elif defined(__OpenBSD__)
+
+#	include <sys/endian.h>
+
+#elif defined(__NetBSD__) || defined(__FreeBSD__) || defined(__DragonFly__)
+
+#	include <sys/endian.h>
+
+#	define be16toh(x) betoh16(x)
+#	define le16toh(x) letoh16(x)
+
+#	define be32toh(x) betoh32(x)
+#	define le32toh(x) letoh32(x)
+
+#	define be64toh(x) betoh64(x)
+#	define le64toh(x) letoh64(x)
+
+#elif defined(__WINDOWS__)
+
+#	include <winsock2.h>
+#	include <sys/param.h>
+
+#	if BYTE_ORDER == LITTLE_ENDIAN
+
+#		define htobe16(x) htons(x)
+#		define htole16(x) (x)
+#		define be16toh(x) ntohs(x)
+#		define le16toh(x) (x)
+ 
+#		define htobe32(x) htonl(x)
+#		define htole32(x) (x)
+#		define be32toh(x) ntohl(x)
+#		define le32toh(x) (x)
+ 
+#		define htobe64(x) htonll(x)
+#		define htole64(x) (x)
+#		define be64toh(x) ntohll(x)
+#		define le64toh(x) (x)
+
+#	elif BYTE_ORDER == BIG_ENDIAN
+
+		/* that would be xbox 360 */
+#		define htobe16(x) (x)
+#		define htole16(x) __builtin_bswap16(x)
+#		define be16toh(x) (x)
+#		define le16toh(x) __builtin_bswap16(x)
+ 
+#		define htobe32(x) (x)
+#		define htole32(x) __builtin_bswap32(x)
+#		define be32toh(x) (x)
+#		define le32toh(x) __builtin_bswap32(x)
+ 
+#		define htobe64(x) (x)
+#		define htole64(x) __builtin_bswap64(x)
+#		define be64toh(x) (x)
+#		define le64toh(x) __builtin_bswap64(x)
+
+#	else
+
+#		error byte order not supported
+
+#	endif
+
+#	define __BYTE_ORDER    BYTE_ORDER
+#	define __BIG_ENDIAN    BIG_ENDIAN
+#	define __LITTLE_ENDIAN LITTLE_ENDIAN
+#	define __PDP_ENDIAN    PDP_ENDIAN
+
+#else
+
+#	error platform not supported
+
+#endif
+
+#endif
+
diff --git a/libelf/src/system.h b/libelf/src/system.h
index 5b6b8dfdfc..c23ad05db4 100644
--- a/libelf/src/system.h
+++ b/libelf/src/system.h
@@ -33,23 +33,13 @@
 #include <stddef.h>
 #include <stdint.h>
 #include <sys/param.h>
-#include <endian.h>
-#include <byteswap.h>
+#include "portable_endian.h"
 #include <unistd.h>
 
-#if __BYTE_ORDER == __LITTLE_ENDIAN
-# define LE32(n)	(n)
-# define LE64(n)	(n)
-# define BE32(n)	bswap_32 (n)
-# define BE64(n)	bswap_64 (n)
-#elif __BYTE_ORDER == __BIG_ENDIAN
-# define BE32(n)	(n)
-# define BE64(n)	(n)
-# define LE32(n)	bswap_32 (n)
-# define LE64(n)	bswap_64 (n)
-#else
-# error "Unknown byte order"
-#endif
+# define LE32(n)	le32toh (n)
+# define LE64(n)	le64toh (n)
+# define BE32(n)	be32toh (n)
+# define BE64(n)	be64toh (n)
 
 #ifndef MAX
 #define MAX(m, n) ((m) < (n) ? (n) : (m))