Sat Aug 25 14:41:22 2018 UTC ()

Pull up following revision(s) (requested by kre in ticket #987):

	bin/sh/trap.c: revision 1.44

PR bin/36532 (perhaps)

This is more or less the same patch as provided in the PR
(just 11 years later, so changed a bit) by woods@...

Since there is no known way to actually cause the reported crash,
we may never know if this change actually fixes anything.   But
even if it doesn't it certainly cannot hurt.

There is a potential race which could possibly explain the issue
(see commentary in the PR) which is not easy to avoid - if that is
the actual cause, this should provide a defence, if not really a fix.


(martin)

diff -r1.40.2.1 -r1.40.2.2 src/bin/sh/trap.c

--- src/bin/sh/trap.c 2017/07/23 14:58:14	1.40.2.1
+++ src/bin/sh/trap.c 2018/08/25 14:41:21	1.40.2.2

 @@ -1,14 +1,14 @@
-/*	$NetBSD: trap.c,v 1.40.2.1 2017/07/23 14:58:14 snj Exp $	*/
+/*	$NetBSD: trap.c,v 1.40.2.2 2018/08/25 14:41:21 martin Exp $	*/
 /*-
  * Copyright (c) 1991, 1993
  *	The Regents of the University of California.  All rights reserved.
+ *
  * This code is derived from software contributed to Berkeley by
  * Kenneth Almquist.
+ *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
 @@ -27,27 +27,27 @@
  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  */
 #include <sys/cdefs.h>
 #ifndef lint
 #if 0
 static char sccsid[] = "@(#)trap.c	8.5 (Berkeley) 6/5/95";
 #else
-__RCSID("$NetBSD: trap.c,v 1.40.2.1 2017/07/23 14:58:14 snj Exp $");
+__RCSID("$NetBSD: trap.c,v 1.40.2.2 2018/08/25 14:41:21 martin Exp $");
 #endif
 #endif /* not lint */
 #include <signal.h>
 #include <unistd.h>
 #include <stdlib.h>
 #include <stdio.h>
 #include "shell.h"
 #include "main.h"
 #include "nodes.h"	/* for other headers */
 #include "eval.h"
 #include "jobs.h"
 @@ -513,29 +513,31 @@ dotrap(void)
 	for (;;) {
 		for (i = 1 ; ; i++) {
 			if (i >= NSIG) {
 				pendingsigs = 0;
 				return;
+			}
 			if (gotsig[i])
 				break;
+		}
 		gotsig[i] = 0;
 		savestatus=exitstatus;
 		CTRACE(DBG_TRAP|DBG_SIG, ("dotrap %d: \"%s\"\n", i,
 		    trap[i] ? trap[i] : "-NULL-"));
-		tr = savestr(trap[i]);		/* trap code may free trap[i] */
+		if ((tr = trap[i]) != NULL) {
-		evalstring(tr, 0);
+			tr = savestr(tr);	/* trap code may free trap[i] */
-		ckfree(tr);
+			evalstring(tr, 0);
 			ckfree(tr);
+		}
 		exitstatus=savestatus;
+	}
+}
 int
 lastsig(void)
+{
 	int i;
 	for (i = NSIG; --i > 0; )
 		if (gotsig[i])
 			return i;
 	return SIGINT;	/* XXX */