Avoid printing f->f_lasttime and/or f->f_prevhost if they are empty.

This fixes a long-standing issue where syslogd would print 15 NUL
bytes followed by two blank spaces before the log message for
warnings generated while parsing syslog.conf.  OK bluhm@

diff --git a/usr.sbin/syslogd/syslogd.c b/usr.sbin/syslogd/syslogd.c
index e916ef1..a3f83d6 100644 (file)
--- a/usr.sbin/syslogd/syslogd.c
+++ b/usr.sbin/syslogd/syslogd.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: syslogd.c,v 1.206 2016/07/01 15:00:48 millert Exp $   */
+/*     $OpenBSD: syslogd.c,v 1.207 2016/07/01 15:47:15 millert Exp $   */
 
 /*
  * Copyright (c) 1983, 1988, 1993, 1994
@@ -1738,20 +1738,36 @@ fprintlog(struct filed *f, int flags, char *msg)
                v->iov_base = "";
                v->iov_len = 0;
                v++;
-       } else {
+       } else if (f->f_lasttime[0] != '\0') {
                v->iov_base = f->f_lasttime;
                v->iov_len = 15;
                v++;
                v->iov_base = " ";
                v->iov_len = 1;
                v++;
+       } else {
+               v->iov_base = "";
+               v->iov_len = 0;
+               v++;
+               v->iov_base = "";
+               v->iov_len = 0;
+               v++;
+       }
+       if (f->f_prevhost[0] != '\0') {
+               v->iov_base = f->f_prevhost;
+               v->iov_len = strlen(v->iov_base);
+               v++;
+               v->iov_base = " ";
+               v->iov_len = 1;
+               v++;
+       } else {
+               v->iov_base = "";
+               v->iov_len = 0;
+               v++;
+               v->iov_base = "";
+               v->iov_len = 0;
+               v++;
        }
-       v->iov_base = f->f_prevhost;
-       v->iov_len = strlen(v->iov_base);
-       v++;
-       v->iov_base = " ";
-       v->iov_len = 1;
-       v++;
 
        if (msg) {
                v->iov_base = msg;