From f6f6004c292501eb91df20db08017496591b5f10 Mon Sep 17 00:00:00 2001
From: "Justin T. Gibbs" <gibbs@FreeBSD.org>
Date: Wed, 31 Jan 1996 18:05:19 +0000
Subject: [PATCH] Properly calculate the amount of the devconf to output in
 SYSCTL_OUT. The code outputs the dc then calls the device specific
 externalize routines to fill in the dc_data area.  The old code assumed that
 dc_data started one byte from the end of the dc, but with the compiler
 optimizing alignment and padding, this isn't always the case.  Do an explicit
 &(dc.dc_data) - &dc.  This fixes lsdev -c which must have been broken for
 some time.

---
 sys/kern/kern_devconf.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/sys/kern/kern_devconf.c b/sys/kern/kern_devconf.c
index 33becac9a3e0..c9c8ba5bff25 100644
--- a/sys/kern/kern_devconf.c
+++ b/sys/kern/kern_devconf.c
@@ -22,7 +22,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- *	$Id: kern_devconf.c,v 1.12 1995/12/06 23:37:06 bde Exp $
+ *	$Id: kern_devconf.c,v 1.13 1995/12/14 08:31:17 phk Exp $
  */
 
 /*
@@ -151,7 +151,15 @@ sysctl_hw_devconfig SYSCTL_HANDLER_ARGS
 
 	make_devconf(kdc, &dc);
 
-	rv = SYSCTL_OUT(req, &dc, (sizeof dc) -1);
+	/*
+	 * Let the device specific externalization routines
+	 * handle the variable length data at the end of the
+	 * dc.  Since the compiler may optimize alignment and
+	 * perform padding, we must do the subtraction to
+	 * determine the proper length. (dc_datalen includes the
+	 * externalized data so it can't be used)
+	 */
+	rv = SYSCTL_OUT(req, &dc, (void *)&dc.dc_data - (void *)&dc);
 	if(rv)
 		return rv;