Don't read before the beginning of the log message if it is zero-length

(possible when it comes from stdin).

Tweaked version of a fix from Peter Hendrickson in PR 6423.

ok deraadt

diff --git a/usr.bin/rcs/rcs.c b/usr.bin/rcs/rcs.c
index 67da998..1e51db1 100644 (file)
--- a/usr.bin/rcs/rcs.c
+++ b/usr.bin/rcs/rcs.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: rcs.c,v 1.55 2010/07/09 20:07:05 naddy Exp $  */
+/*     $OpenBSD: rcs.c,v 1.56 2010/07/13 20:07:24 nicm Exp $   */
 /*
  * Copyright (c) 2004 Jean-Francois Brousseau <jfb@openbsd.org>
  * All rights reserved.
@@ -497,7 +497,7 @@ rcs_write(RCSFILE *rfp)
                if (rdp->rd_log != NULL) {
                        len = strlen(rdp->rd_log);
                        rcs_strprint((const u_char *)rdp->rd_log, len, fp);
-                       if (rdp->rd_log[len-1] != '\n')
+                       if (len == 0 || rdp->rd_log[len-1] != '\n')
                                fputc('\n', fp);
                }
                fputs("@\ntext\n@", fp);