Use offsetof() instead of adding the sizes of the preceeding struct members

ok millert@

diff --git a/usr.bin/kdump/ktrstruct.c b/usr.bin/kdump/ktrstruct.c
index a19971e..609e6a4 100644 (file)
--- a/usr.bin/kdump/ktrstruct.c
+++ b/usr.bin/kdump/ktrstruct.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: ktrstruct.c,v 1.12 2015/10/09 01:37:08 deraadt Exp $  */
+/*     $OpenBSD: ktrstruct.c,v 1.13 2015/10/18 05:03:22 guenther Exp $ */
 
 /*-
  * Copyright (c) 1988, 1993
@@ -45,6 +45,7 @@
 #include <netdb.h>
 #include <poll.h>
 #include <signal.h>
+#include <stddef.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <stdint.h>
@@ -117,13 +118,12 @@ ktrsockaddr(struct sockaddr *sa)
                struct sockaddr_un *sa_un;
 
                sa_un = (struct sockaddr_un *)sa;
-               if (sa_un->sun_len <= sizeof(sa_un->sun_len) +
-                   sizeof(sa_un->sun_family)) {
+               if (sa_un->sun_len <= offsetof(struct sockaddr_un, sun_path)) {
                        printf("invalid");
                        break;
                }
                printf("\"%.*s\"", (int)(sa_un->sun_len -
-                   sizeof(sa_un->sun_len) - sizeof(sa_un->sun_family)),
+                   offsetof(struct sockaddr_un, sun_path)),
                    sa_un->sun_path);
                break;
        }