Index: head/lib/libnetbsd/Makefile
===================================================================
--- head/lib/libnetbsd/Makefile
+++ head/lib/libnetbsd/Makefile
@@ -7,7 +7,7 @@
 
 CFLAGS+=	-I${.CURDIR}
 
-SRCS+=	sockaddr_snprintf.c strsuftoll.c util.c util.h
+SRCS+=	efun.c sockaddr_snprintf.c strsuftoll.c util.c util.h
 
 INTERNALLIB=
 
Index: head/lib/libnetbsd/efun.c
===================================================================
--- head/lib/libnetbsd/efun.c
+++ head/lib/libnetbsd/efun.c
@@ -0,0 +1,160 @@
+/*	$NetBSD: efun.c,v 1.10 2015/07/26 02:20:30 kamil Exp $	*/
+/*	$FreeBSD$ */
+
+/*-
+ * Copyright (c) 2006 The NetBSD Foundation, Inc.
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to The NetBSD Foundation
+ * by Christos Zoulas.
+ *
+ * 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
+ */
+
+#if HAVE_NBTOOL_CONFIG_H
+#include "nbtool_config.h"
+#endif
+
+#include <sys/cdefs.h>
+#ifdef __RCSID
+__RCSID("$NetBSD: efun.c,v 1.10 2015/07/26 02:20:30 kamil Exp $");
+#endif
+
+#include <err.h>
+#include <errno.h>
+#include <inttypes.h>
+#include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdarg.h>
+#include <util.h>
+
+static void (*efunc)(int, const char *, ...) = err;
+
+void (*
+esetfunc(void (*ef)(int, const char *, ...)))(int, const char *, ...)
+{
+	void (*of)(int, const char *, ...) = efunc;
+	efunc = ef == NULL ? (void (*)(int, const char *, ...))exit : ef;
+	return of;
+}
+
+size_t
+estrlcpy(char *dst, const char *src, size_t len)
+{
+	size_t rv;
+	if ((rv = strlcpy(dst, src, len)) >= len) {
+		errno = ENAMETOOLONG;
+		(*efunc)(1,
+		    "Cannot copy string; %zu chars needed %zu provided",
+		    rv, len);
+	}
+	return rv;
+}
+
+size_t
+estrlcat(char *dst, const char *src, size_t len)
+{
+	size_t rv;
+	if ((rv = strlcat(dst, src, len)) >= len) {
+		errno = ENAMETOOLONG;
+		(*efunc)(1,
+		    "Cannot append to string; %zu chars needed %zu provided",
+		    rv, len);
+	}
+	return rv;
+}
+
+char *
+estrdup(const char *s)
+{
+	char *d = strdup(s);
+	if (d == NULL)
+		(*efunc)(1, "Cannot copy string");
+	return d;
+}
+
+char *
+estrndup(const char *s, size_t len)
+{
+	char *d = strndup(s, len);
+	if (d == NULL)
+		(*efunc)(1, "Cannot copy string");
+	return d;
+}
+
+void *
+emalloc(size_t n)
+{
+	void *p = malloc(n);
+	if (p == NULL && n != 0)
+		(*efunc)(1, "Cannot allocate %zu bytes", n);
+	return p;
+}
+
+void *
+ecalloc(size_t n, size_t s)
+{
+	void *p = calloc(n, s);
+	if (p == NULL && n != 0 && s != 0)
+		(*efunc)(1, "Cannot allocate %zu blocks of size %zu", n, s);
+	return p;
+}
+
+void *
+erealloc(void *p, size_t n)
+{
+	void *q = realloc(p, n);
+	if (q == NULL && n != 0)
+		(*efunc)(1, "Cannot re-allocate %zu bytes", n);
+	return q;
+}
+
+FILE *
+efopen(const char *p, const char *m)
+{
+	FILE *fp = fopen(p, m);
+	if (fp == NULL)
+		(*efunc)(1, "Cannot open `%s'", p);
+	return fp;
+}
+
+int
+easprintf(char ** __restrict ret, const char * __restrict format, ...)
+{
+	int rv;
+	va_list ap;
+	va_start(ap, format);
+	if ((rv = vasprintf(ret, format, ap)) == -1)
+		(*efunc)(1, "Cannot format string");
+	va_end(ap);
+	return rv;
+}
+
+int
+evasprintf(char ** __restrict ret, const char * __restrict format, va_list ap)
+{
+	int rv;
+	if ((rv = vasprintf(ret, format, ap)) == -1)
+		(*efunc)(1, "Cannot format string");
+	return rv;
+}
Index: head/lib/libnetbsd/util.h
===================================================================
--- head/lib/libnetbsd/util.h
+++ head/lib/libnetbsd/util.h
@@ -36,6 +36,19 @@
 #include <sys/types.h>
 #include <libutil.h>
 
+void	(*esetfunc(void (*)(int, const char *, ...)))(int, const char *, ...);
+size_t	 estrlcpy(char *, const char *, size_t);
+size_t	 estrlcat(char *, const char *, size_t);
+char	*estrdup(const char *);
+char	*estrndup(const char *, size_t);
+void	*emalloc(size_t);
+void	*ecalloc(size_t, size_t);
+void	*erealloc(void *, size_t);
+struct __sFILE	*efopen(const char *, const char *);
+int	 easprintf(char ** __restrict, const char * __restrict, ...)
+	    __printflike(2, 3);
+int	 evasprintf(char ** __restrict, const char * __restrict, __va_list)
+	    __printflike(2, 0);
 char	*flags_to_string(u_long flags, const char *def);
 int	 sockaddr_snprintf(char *, size_t, const char *,
 			   const struct sockaddr *);