From 53d745bc7c69c92531f7ef4c29ed5cb784cf0f91 Mon Sep 17 00:00:00 2001
From: Dima Dorfman <dd@FreeBSD.org>
Date: Thu, 20 Dec 2001 06:38:21 +0000
Subject: [PATCH] Actually make use of the md_version field of 'struct mdio'. 
 In order not to needlessly break compatibility, decrement MDIOVERSION to 0.

Approved by:	phk
---
 sbin/mdconfig/mdconfig.c |  2 ++
 sys/dev/md/md.c          | 13 +++++++++++++
 sys/sys/mdioctl.h        |  2 +-
 3 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/sbin/mdconfig/mdconfig.c b/sbin/mdconfig/mdconfig.c
index b5367621f715..8a6019f008ce 100644
--- a/sbin/mdconfig/mdconfig.c
+++ b/sbin/mdconfig/mdconfig.c
@@ -161,6 +161,7 @@ main(int argc, char **argv)
 			usage();
 		}
 	}
+	mdio.md_version = MDIOVERSION;
 
 	mdmaybeload();
 	fd = open("/dev/" MDCTL_NAME, O_RDWR, 0);
@@ -253,6 +254,7 @@ int
 query(const int fd, const int unit)
 {
 
+	mdio.md_version = MDIOVERSION;
 	mdio.md_unit = unit;
 
 	if (ioctl(fd, MDIOCQUERY, &mdio) < 0)
diff --git a/sys/dev/md/md.c b/sys/dev/md/md.c
index bb4b7f0765e4..ef2273160203 100644
--- a/sys/dev/md/md.c
+++ b/sys/dev/md/md.c
@@ -831,9 +831,18 @@ mdctlioctl(dev_t dev, u_long cmd, caddr_t addr, int flags, struct thread *td)
 		printf("mdctlioctl(%s %lx %p %x %p)\n",
 			devtoname(dev), cmd, addr, flags, td);
 
+	/*
+	 * We assert the version number in the individual ioctl
+	 * handlers instead of out here because (a) it is possible we
+	 * may add another ioctl in the future which doesn't read an
+	 * mdio, and (b) the correct return value for an unknown ioctl
+	 * is ENOIOCTL, not EINVAL.
+	 */
 	mdio = (struct md_ioctl *)addr;
 	switch (cmd) {
 	case MDIOCATTACH:
+		if (mdio->md_version != MDIOVERSION)
+			return (EINVAL);
 		switch (mdio->md_type) {
 		case MD_MALLOC:
 			return (mdcreate_malloc(mdio));
@@ -847,11 +856,15 @@ mdctlioctl(dev_t dev, u_long cmd, caddr_t addr, int flags, struct thread *td)
 			return (EINVAL);
 		}
 	case MDIOCDETACH:
+		if (mdio->md_version != MDIOVERSION)
+			return (EINVAL);
 		if (mdio->md_file != NULL || mdio->md_size != 0 ||
 		    mdio->md_options != 0)
 			return (EINVAL);
 		return (mddetach(mdio->md_unit, td));
 	case MDIOCQUERY:
+		if (mdio->md_version != MDIOVERSION)
+			return (EINVAL);
 		sc = mdfind(mdio->md_unit);
 		if (sc == NULL)
 			return (ENOENT);
diff --git a/sys/sys/mdioctl.h b/sys/sys/mdioctl.h
index 6b16fde61f14..c311ccaaab36 100644
--- a/sys/sys/mdioctl.h
+++ b/sys/sys/mdioctl.h
@@ -66,7 +66,7 @@ struct md_ioctl {
 
 #define MD_NAME		"md"
 #define MDCTL_NAME	"mdctl"
-#define MDIOVERSION	1
+#define MDIOVERSION	0
 
 /*
  * Before you can use a unit, it must be configured with MDIOCSET.