diff --git a/bin/ed/buf.c b/bin/ed/buf.c
index 34574c569eb..5749b0d668d 100644
--- a/bin/ed/buf.c
+++ b/bin/ed/buf.c
@@ -31,7 +31,7 @@
 static char * const rcsid = "@(#)buf.c,v 1.4 1994/02/01 00:34:35 alm Exp";
 #else
 static char * const rcsid =
-	"$Id: buf.c,v 1.11 1997/03/24 05:45:29 imp Exp $";
+	"$Id: buf.c,v 1.12 1997/08/07 21:33:39 steve Exp $";
 #endif
 #endif /* not lint */
 
@@ -208,7 +208,8 @@ open_sbuf()
 	isbinary = newline_added = 0;
 	u = umask(077);
 	strcpy(sfn, "/tmp/ed.XXXXXX");
-	if ((fd = mkstemp(sfn)) == -1 ||
+	if (mktemp(sfn) == NULL ||
+	    (fd = open(sfn, O_RDWR|O_CREAT|O_EXCL, 0666)) == -1 ||
 	    (sfp = fdopen(fd, "w+")) == NULL) {
 		if (fd != -1)
 			close(fd);