Add mallocarray(9)

While here, change malloc(9)'s size argument from "unsigned long" to
"size_t".

ok tedu

4 files changed, 62 insertions, 14 deletions

diff --git a/share/man/man9/Makefile b/share/man/man9/Makefile
index c880323e6d8..e2a761d1faf 100644
--- a/share/man/man9/Makefile
+++ b/share/man/man9/Makefile
@@ -1,4 +1,4 @@
-#	$OpenBSD: Makefile,v 1.213 2014/07/09 18:00:09 jmc Exp $
+#	$OpenBSD: Makefile,v 1.214 2014/07/10 19:33:16 matthew Exp $
 #	$NetBSD: Makefile,v 1.4 1996/01/09 03:23:01 thorpej Exp $
 
 #	Makefile for section 9 (kernel function and variable) manual pages.
@@ -235,7 +235,7 @@ MLINKS+=ktrace.9 ktrcsw.9 ktrace.9 ktremul.9 ktrace.9 ktrgenio.9 \
 	ktrace.9 ktrsysret.9 ktrace.9 KTRPOINT.9
 MLINKS+=lock.9 lockinit.9 lock.9 lockmgr.9 lock.9 lockstatus.9
 MLINKS+=log.9 addlog.9
-MLINKS+=malloc.9 free.9
+MLINKS+=malloc.9 mallocarray.9 malloc.9 free.9
 MLINKS+=membar_sync.9 membar_enter.9 membar_sync.9 membar_exit.9 \
 	membar_sync.9 membar_producer.9 membar_sync.9 membar_consumer.9
 MLINKS+=mbuf.9 m_copym2.9 mbuf.9 m_copym.9 mbuf.9 m_free.9 mbuf.9 MFREE.9 \
diff --git a/share/man/man9/malloc.9 b/share/man/man9/malloc.9
index 78955677e2b..90737b7b43c 100644
--- a/share/man/man9/malloc.9
+++ b/share/man/man9/malloc.9
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: malloc.9,v 1.52 2014/04/03 04:10:34 lteo Exp $
+.\"	$OpenBSD: malloc.9,v 1.53 2014/07/10 19:33:16 matthew Exp $
 .\"	$NetBSD: malloc.9,v 1.2 1996/10/30 05:29:54 lukem Exp $
 .\"
 .\" Copyright (c) 1996 The NetBSD Foundation, Inc.
@@ -28,18 +28,21 @@
 .\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 .\" POSSIBILITY OF SUCH DAMAGE.
 .\"
-.Dd $Mdocdate: April 3 2014 $
+.Dd $Mdocdate: July 10 2014 $
 .Dt MALLOC 9
 .Os
 .Sh NAME
 .Nm malloc ,
+.Nm mallocarray ,
 .Nm free
 .Nd kernel memory allocator
 .Sh SYNOPSIS
 .In sys/types.h
 .In sys/malloc.h
 .Ft void *
-.Fn malloc "unsigned long size" "int type" "int flags"
+.Fn malloc "size_t size" "int type" "int flags"
+.Ft void *
+.Fn malloc "size_t nmemb" "size_t size" "int type" "int flags"
 .Ft void
 .Fn free "void *addr" "int type"
 .Sh DESCRIPTION
@@ -48,8 +51,17 @@ The
 function allocates uninitialized memory in kernel address space for an
 object whose size is specified by
 .Fa size .
+The
+.Fn mallocarray
+function is the same as
+.Fn malloc ,
+except it allocates space for an array of
+.Fa nmemb
+objects and checks for arithmetic overflow.
+.Pp
+The
 .Fn free
-releases memory at address
+function releases memory at address
 .Fa addr
 that was previously allocated by
 .Fn malloc
@@ -60,7 +72,8 @@ is a null pointer, no action occurs.
 .Pp
 The
 .Fa flags
-argument further qualifies malloc's
+argument further qualifies
+.Fn malloc Ns 's
 operational characteristics as follows:
 .Bl -tag -width xxx -offset indent
 .It Dv M_WAITOK
diff --git a/sys/kern/kern_malloc.c b/sys/kern/kern_malloc.c
index c519348d709..f071962cd9a 100644
--- a/sys/kern/kern_malloc.c
+++ b/sys/kern/kern_malloc.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: kern_malloc.c,v 1.110 2014/07/10 10:53:45 deraadt Exp $	*/
+/*	$OpenBSD: kern_malloc.c,v 1.111 2014/07/10 19:33:16 matthew Exp $	*/
 /*	$NetBSD: kern_malloc.c,v 1.15.4.2 1996/06/13 17:10:56 cgd Exp $	*/
 
 /*
@@ -155,7 +155,7 @@ struct timeval malloc_lasterr;
  * Allocate a block of memory
  */
 void *
-malloc(unsigned long size, int type, int flags)
+malloc(size_t size, int type, int flags)
 {
 	struct kmembuckets *kbp;
 	struct kmemusage *kup;
@@ -697,3 +697,37 @@ malloc_printit(
 #endif
 }
 #endif /* DDB */
+
+/*
+ * Copyright (c) 2008 Otto Moerbeek <otto@drijf.net>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+/*
+ * This is sqrt(SIZE_MAX+1), as s1*s2 <= SIZE_MAX
+ * if both s1 < MUL_NO_OVERFLOW and s2 < MUL_NO_OVERFLOW
+ */
+#define MUL_NO_OVERFLOW	(1UL << (sizeof(size_t) * 4))
+
+void *
+mallocarray(size_t nmemb, size_t size, int type, int flags)
+{
+	if ((nmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) &&
+	    nmemb > 0 && SIZE_MAX / nmemb < size) {
+		if (flags & M_CANFAIL)
+			return (NULL);
+		panic("mallocarray overflow: %zu * %zu", nmemb, size);
+	}
+	return (malloc(size * nmemb, type, flags));
+}
diff --git a/sys/sys/malloc.h b/sys/sys/malloc.h
index b04b6f712e4..717831266e6 100644
--- a/sys/sys/malloc.h
+++ b/sys/sys/malloc.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: malloc.h,v 1.108 2014/05/19 14:30:03 tedu Exp $	*/
+/*	$OpenBSD: malloc.h,v 1.109 2014/07/10 19:33:16 matthew Exp $	*/
 /*	$NetBSD: malloc.h,v 1.39 1998/07/12 19:52:01 augustss Exp $	*/
 
 /*
@@ -391,10 +391,11 @@ extern struct kmemusage *kmemusage;
 extern char *kmembase;
 extern struct kmembuckets bucket[];
 
-extern void *malloc(unsigned long size, int type, int flags);
-extern void free(void *addr, int type);
-extern int sysctl_malloc(int *, u_int, void *, size_t *, void *, size_t,
-			      struct proc *);
+void	*malloc(size_t, int, int);
+void	*mallocarray(size_t, size_t, int, int);
+void	free(void *, int);
+int	sysctl_malloc(int *, u_int, void *, size_t *, void *, size_t,
+	    struct proc *);
 
 size_t malloc_roundup(size_t);
 void	malloc_printit(int (*)(const char *, ...));