diff --git a/lib/log.c b/lib/log.c
index 04aa3cfa..6ab1701f 100644
--- a/lib/log.c
+++ b/lib/log.c
@@ -19,6 +19,7 @@
 #include <lastlog.h>
 #include "memzero.h"
 #include "prototypes.h"
+#include "strncpy.h"
 #include "strtcpy.h"
 
 
@@ -82,7 +83,7 @@ void dolastlog (
 	newlog.ll_time = ll_time;
 	STRTCPY(newlog.ll_line, line);
 #if HAVE_LL_HOST
-	strncpy(newlog.ll_host, host, sizeof(newlog.ll_host));
+	STRNCPY(newlog.ll_host, host);
 #endif
 	if (   (lseek (fd, offset, SEEK_SET) != offset)
 	    || (write_full(fd, &newlog, sizeof newlog) == -1)
diff --git a/lib/utmp.c b/lib/utmp.c
index 0ec2692c..7f116f3b 100644
--- a/lib/utmp.c
+++ b/lib/utmp.c
@@ -25,6 +25,7 @@
 #include "alloc.h"
 #include "sizeof.h"
 #include "strtcpy.h"
+#include "strncpy.h"
 #include "zustr2stp.h"
 
 #ident "$Id$"
@@ -262,25 +263,25 @@ static
 	utent->ut_type = USER_PROCESS;
 #endif				/* HAVE_STRUCT_UTMP_UT_TYPE */
 	utent->ut_pid = getpid ();
-	strncpy(utent->ut_line, line, sizeof(utent->ut_line));
+	STRNCPY(utent->ut_line, line);
 #ifdef HAVE_STRUCT_UTMP_UT_ID
 	if (NULL != ut) {
-		strncpy (utent->ut_id, ut->ut_id, sizeof (utent->ut_id));
+		STRNCPY(utent->ut_id, ut->ut_id);
 	} else {
 		/* XXX - assumes /dev/tty?? */
-		strncpy(utent->ut_id, line + 3, sizeof(utent->ut_id));
+		STRNCPY(utent->ut_id, line + 3);
 	}
 #endif				/* HAVE_STRUCT_UTMP_UT_ID */
 #ifdef HAVE_STRUCT_UTMP_UT_NAME
-	strncpy (utent->ut_name, name,      sizeof (utent->ut_name));
+	STRNCPY(utent->ut_name, name);
 #endif				/* HAVE_STRUCT_UTMP_UT_NAME */
 #ifdef HAVE_STRUCT_UTMP_UT_USER
-	strncpy(utent->ut_user, name, sizeof(utent->ut_user));
+	STRNCPY(utent->ut_user, name);
 #endif				/* HAVE_STRUCT_UTMP_UT_USER */
 	if (NULL != hostname) {
 		struct addrinfo *info = NULL;
 #ifdef HAVE_STRUCT_UTMP_UT_HOST
-		strncpy(utent->ut_host, hostname, sizeof(utent->ut_host));
+		STRNCPY(utent->ut_host, hostname);
 #endif				/* HAVE_STRUCT_UTMP_UT_HOST */
 #ifdef HAVE_STRUCT_UTMP_UT_SYSLEN
 		utent->ut_syslen = MIN (strlen (hostname),