From 5c648baca8186df6100ae1386605cd0963ed4e89 Mon Sep 17 00:00:00 2001
From: Poul-Henning Kamp <phk@FreeBSD.org>
Date: Sat, 28 Dec 2002 22:17:29 +0000
Subject: [PATCH] It is bad style to define the same structure in multiple
 header files which might be included together.

Things like debuggers and lint-like programs get their knickers in
a twist (rightly so one might add) when they find different locations
for the same named struct depending on which .h file were included
first.

This is a stellar example of Very Bad Thinking on the part of the
standards dudes who wrote that both sys/uio.h and sys/socket.h
should define struct iovec the same way.

Fix this by putting struct iovec into its own miniature sys/_iovec.h
file and #include that from sys/socket.h and sys/uio.h.

Sensible people could just put iovec into sys/_types.h but there
is probably some standard or other which will be violated if we
did something that horrible.
---
 sys/sys/_iovec.h | 45 +++++++++++++++++++++++++++++++++++++++++++++
 sys/sys/socket.h |  9 +--------
 sys/sys/uio.h    |  9 +--------
 3 files changed, 47 insertions(+), 16 deletions(-)
 create mode 100644 sys/sys/_iovec.h

diff --git a/sys/sys/_iovec.h b/sys/sys/_iovec.h
new file mode 100644
index 00000000000..fac5f27306f
--- /dev/null
+++ b/sys/sys/_iovec.h
@@ -0,0 +1,45 @@
+/*
+ * Copyright (c) 1982, 1986, 1993, 1994
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)uio.h	8.5 (Berkeley) 2/22/94
+ * $FreeBSD$
+ */
+
+#ifndef _SYS__IOVEC_H_
+#define	_SYS__IOVEC_H_
+
+struct iovec {
+	void	*iov_base;	/* Base address. */
+	size_t	 iov_len;	/* Length. */
+};
+
+#endif /* !_SYS__IOVEC_H_ */
diff --git a/sys/sys/socket.h b/sys/sys/socket.h
index a38b2170607..a078c4fe310 100644
--- a/sys/sys/socket.h
+++ b/sys/sys/socket.h
@@ -39,6 +39,7 @@
 
 #include <sys/cdefs.h>
 #include <sys/_types.h>
+#include <sys/_iovec.h>
 #define _NO_NAMESPACE_POLLUTION
 #include <machine/param.h>
 #undef _NO_NAMESPACE_POLLUTION
@@ -370,14 +371,6 @@ struct sockaddr_storage {
  */
 #define	SOMAXCONN	128
 
-#ifndef _STRUCT_IOVEC_DECLARED
-#define	_STRUCT_IOVEC_DECLARED
-struct iovec {
-	void	*iov_base;	/* Base address. */
-	size_t	iov_len;	/* Length. */
-};
-#endif
-
 /*
  * Message header for recvmsg and sendmsg calls.
  * Used value-result for recvmsg, value only for sendmsg.
diff --git a/sys/sys/uio.h b/sys/sys/uio.h
index 8e4fd6f6a52..e180356d87a 100644
--- a/sys/sys/uio.h
+++ b/sys/sys/uio.h
@@ -39,6 +39,7 @@
 
 #include <sys/cdefs.h>
 #include <sys/_types.h>
+#include <sys/_iovec.h>
 
 #ifndef _SIZE_T_DECLARED
 typedef	__size_t	size_t;
@@ -50,14 +51,6 @@ typedef	__ssize_t	ssize_t;
 #define	_SSIZE_T_DECLARED
 #endif
 
-#ifndef _STRUCT_IOVEC_DECLARED
-#define	_STRUCT_IOVEC_DECLARED
-struct iovec {
-	void	*iov_base;	/* Base address. */
-	size_t	 iov_len;	/* Length. */
-};
-#endif
-
 #if __BSD_VISIBLE
 enum	uio_rw { UIO_READ, UIO_WRITE };