KASSERTMSG(9): New kernel assertion with message

KASSERT() is annoying as it only prints the expression as a string.  If you
(developers) want to know a little more information, you have to do:

	#ifdef DIAGNOSTIC
		if (bad)
			panic(...);
	#endif

KASSERTMSG() replaces it into a single line:

		KASSERTMSG(!bad, ...);

Taken from NetBSD.

(There is a concern that KASSERT() messages are too long; consume more memory,
and not friendly for small monitors.  This have to be considered & revisited
later.)

"Like" from henning@
Man page review & advices from jmc@ and schwarze@

5 files changed, 53 insertions, 20 deletions

diff --git a/share/man/man9/Makefile b/share/man/man9/Makefile
index 95453c67680..c69a8933ce9 100644
--- a/share/man/man9/Makefile
+++ b/share/man/man9/Makefile
@@ -1,4 +1,4 @@
-#	$OpenBSD: Makefile,v 1.216 2014/07/13 09:37:22 mpi Exp $
+#	$OpenBSD: Makefile,v 1.217 2014/07/13 23:49:40 uebayasi Exp $
 #	$NetBSD: Makefile,v 1.4 1996/01/09 03:23:01 thorpej Exp $
 
 #	Makefile for section 9 (kernel function and variable) manual pages.
@@ -219,6 +219,7 @@ MLINKS+=iic.9 iic_acquire_bus.9 iic.9 iic_release_bus.9 iic.9 iic_exec.9 \
 MLINKS+=kern.9 imax.9 kern.9 imin.9 kern.9 lmax.9 kern.9 lmin.9 \
 	kern.9 max.9 kern.9 min.9 kern.9 ulmax.9 kern.9 ulmin.9 kern.9 abs.9 \
 	kern.9 assert.9 kern.9 KASSERT.9 kern.9 KDASSERT.9 \
+	kern.9 KASSERTMSG.9 kern.9 KDASSERTMSG.9 \
 	kern.9 skpc.9 kern.9 scanc.9 kern.9 bcmp.9 \
 	kern.9 memchr.9 kern.9 memcmp.9 kern.9 ffs.9 kern.9 fls.9 kern.9 flsl.9 \
 	kern.9 strlen.9 kern.9 strncpy.9 kern.9 strlcpy.9 kern.9 strlcat.9 \
diff --git a/share/man/man9/kern.9 b/share/man/man9/kern.9
index 315572de2d5..8d98eff1b73 100644
--- a/share/man/man9/kern.9
+++ b/share/man/man9/kern.9
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: kern.9,v 1.18 2013/07/11 01:24:12 jsg Exp $
+.\"	$OpenBSD: kern.9,v 1.19 2014/07/13 23:49:40 uebayasi Exp $
 .\"
 .\" Copyright (c) 2002, 2003 CubeSoft Communications, Inc.
 .\" <http://www.csoft.org>
@@ -24,7 +24,7 @@
 .\" IN ANY WAY OUT OF THE USE OF THIS SOFTWARE EVEN IF ADVISED OF THE
 .\" POSSIBILITY OF SUCH DAMAGE.
 .\"
-.Dd $Mdocdate: July 11 2013 $
+.Dd $Mdocdate: July 13 2014 $
 .Dt KERN 9
 .Os
 .Sh NAME
@@ -93,6 +93,10 @@ function computes the absolute value of integer
 .Fn KASSERT "CONDITION"
 .Ft "void"
 .Fn KDASSERT "CONDITION"
+.Ft "void"
+.Fn KASSERTMSG "CONDITION" "fmt" "..."
+.Ft "void"
+.Fn KDASSERTMSG "CONDITION" "fmt" "..."
 .nr nS 0
 .Pp
 These macros cause kernel
@@ -101,13 +105,29 @@ if the given condition evaluates to false.
 .Fn assert
 tests are always compiled in.
 .Fn KASSERT
+and
+.Fn KASSERTMSG
 tests are only included if the kernel has
 .Dv DIAGNOSTIC
 enabled.
 .Fn KDASSERT
+and
+.Fn KDASSERTMSG
 tests are only included if the kernel has
 .Dv DEBUG
 enabled.
+The
+.Fn KASSERTMSG
+and
+.Fn KDASSERTMSG
+macros append
+to the
+.Xr panic 9
+format string the message specified by
+.Fa format
+and its subsequent arguments, similar to
+.Xr printf 9
+functions.
 .Pp
 .nr nS 1
 .Fn CTASSERT "CONDITION"
@@ -251,3 +271,8 @@ The
 and
 .Fn scanc
 functions are based on vax instructions of the same name.
+The
+.Fn KASSERTMSG
+and
+.Fn KDASSERTMSG
+macros are taken from NetBSD.
diff --git a/sys/kern/kern_physio.c b/sys/kern/kern_physio.c
index 60d44331d28..bf588f26ba9 100644
--- a/sys/kern/kern_physio.c
+++ b/sys/kern/kern_physio.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: kern_physio.c,v 1.39 2011/07/18 02:49:20 matthew Exp $	*/
+/*	$OpenBSD: kern_physio.c,v 1.40 2014/07/13 23:49:40 uebayasi Exp $	*/
 /*	$NetBSD: kern_physio.c,v 1.28 1997/05/19 10:43:28 pk Exp $	*/
 
 /*-
@@ -128,12 +128,8 @@ physio(void (*strategy)(struct buf *), dev_t dev, int flags,
 			 */
 			(*minphys)(bp);
 			todo = bp->b_bcount;
-#ifdef DIAGNOSTIC
-			if (todo < 0)
-				panic("todo < 0; minphys broken");
-			if (todo > MAXPHYS)
-				panic("todo > MAXPHYS; minphys broken");
-#endif
+			KASSERTMSG(todo >= 0, "minphys broken");
+			KASSERTMSG(todo <= MAXPHYS, "minphys broken");
 
 			/*
 			 * [lock the part of the user address space involved
@@ -194,12 +190,8 @@ physio(void (*strategy)(struct buf *), dev_t dev, int flags,
 			 *    of data to transfer]
 			 */
 			done = bp->b_bcount - bp->b_resid;
-#ifdef DIAGNOSTIC
-			if (done < 0)
-				panic("done < 0; strategy broken");
-			if (done > todo)
-				panic("done > todo; strategy broken");
-#endif
+			KASSERTMSG(done >= 0, "strategy broken");
+			KASSERTMSG(done <= todo, "strategy broken");
 			iovp->iov_len -= done;
 			iovp->iov_base = (caddr_t)iovp->iov_base + done;
 			uio->uio_offset += done;
diff --git a/sys/kern/subr_prf.c b/sys/kern/subr_prf.c
index ed134d1fe3a..899fcb529d5 100644
--- a/sys/kern/subr_prf.c
+++ b/sys/kern/subr_prf.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: subr_prf.c,v 1.82 2014/07/11 14:36:44 uebayasi Exp $	*/
+/*	$OpenBSD: subr_prf.c,v 1.83 2014/07/13 23:49:40 uebayasi Exp $	*/
 /*	$NetBSD: subr_prf.c,v 1.45 1997/10/24 18:14:25 chuck Exp $	*/
 
 /*-
@@ -156,8 +156,7 @@ void
 __assert(const char *t, const char *f, int l, const char *e)
 {
 
-	panic("kernel %sassertion \"%s\" failed: file \"%s\", line %d",
-		t, e, f, l);
+	panic(__KASSERTSTR, t, e, f, l);
 }
 
 /*
diff --git a/sys/lib/libkern/libkern.h b/sys/lib/libkern/libkern.h
index 4e53f92fbc2..d743920ea0b 100644
--- a/sys/lib/libkern/libkern.h
+++ b/sys/lib/libkern/libkern.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: libkern.h,v 1.33 2014/06/10 04:16:57 deraadt Exp $	*/
+/*	$OpenBSD: libkern.h,v 1.34 2014/07/13 23:49:40 uebayasi Exp $	*/
 /*	$NetBSD: libkern.h,v 1.7 1996/03/14 18:52:08 christos Exp $	*/
 
 /*-
@@ -114,25 +114,41 @@ abs(int j)
 #endif
 #endif
 
+#define	__KASSERTSTR	"kernel %sassertion \"%s\" failed: file \"%s\", line %d"
+
 #ifndef DIAGNOSTIC
+#define	KASSERTMSG(e, msg, ...)	((void)0)
 #define	KASSERT(e)	((void)0)
 #else
 #ifdef __STDC__
+#define	KASSERTMSG(e, msg, ...)	((e) ? (void)0 :			    \
+			    panic(__KASSERTSTR " " msg, "diagnostic ", #e,  \
+			    __FILE__, __LINE__, ## __VA_ARGS__))
 #define	KASSERT(e)	((e) ? (void)0 :				    \
 			    __assert("diagnostic ", __FILE__, __LINE__, #e))
 #else
+#define	KASSERTMSG(e, msg, ...)	((e) ? (void)0 :			    \
+			    panic(__KASSERTSTR " " msg, "diagnostic ", "e", \
+			    __FILE__, __LINE__, ## __VA_ARGS__))
 #define	KASSERT(e)	((e) ? (void)0 :				    \
 			    __assert("diagnostic ", __FILE__, __LINE__, "e"))
 #endif
 #endif
 
 #ifndef DEBUG
+#define	KDASSERTMSG(e, msg, ...)	((void)0)
 #define	KDASSERT(e)	((void)0)
 #else
 #ifdef __STDC__
+#define	KDASSERTMSG(e, msg, ...)	((e) ? (void)0 :		    \
+			    panic(__KASSERTSTR " " msg, "debugging ", #e,   \
+			    __FILE__, __LINE__, ## __VA_ARGS__))
 #define	KDASSERT(e)	((e) ? (void)0 :				    \
 			    __assert("debugging ", __FILE__, __LINE__, #e))
 #else
+#define	KDASSERTMSG(e, msg, ...)	((e) ? (void)0 :		    \
+			    panic(__KASSERTSTR " " msg, "debugging ", "e",  \
+			    __FILE__, __LINE__, ## __VA_ARGS__))
 #define	KDASSERT(e)	((e) ? (void)0 :				    \
 			    __assert("debugging ", __FILE__, __LINE__, "e"))
 #endif