[src/trunk]: src/games/cgram cgram: properly handle input errors

[rillig <rillig%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/b125108c7668
branches:  trunk
changeset: 1018964:b125108c7668
user:      rillig <rillig%NetBSD.org@localhost>
date:      Mon Feb 22 16:28:20 2021 +0000

description:
cgram: properly handle input errors

On both NetBSD and Cygwin, a missing /usr/bin/fortune would previously
continue since popen does not return an error (as /bin/sh is found and
can be executed), so the next chance to catch an error is pclose.  At
that point, the shell has already printed an informative error message
about what happened (or what didn't happen), so that cgram does not need
to print an error by itself.

diffstat:

 games/cgram/cgram.c |  7 ++++---
 1 files changed, 4 insertions(+), 3 deletions(-)

diffs (28 lines):

diff -r 690b2843a0a1 -r b125108c7668 games/cgram/cgram.c
--- a/games/cgram/cgram.c       Mon Feb 22 15:09:50 2021 +0000
+++ b/games/cgram/cgram.c       Mon Feb 22 16:28:20 2021 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: cgram.c,v 1.11 2021/02/21 22:21:56 rillig Exp $ */
+/* $NetBSD: cgram.c,v 1.12 2021/02/22 16:28:20 rillig Exp $ */
 
 /*-
  * Copyright (c) 2013, 2021 The NetBSD Foundation, Inc.
@@ -31,7 +31,7 @@
 
 #include <sys/cdefs.h>
 #if defined(__RCSID) && !defined(lint)
-__RCSID("$NetBSD: cgram.c,v 1.11 2021/02/21 22:21:56 rillig Exp $");
+__RCSID("$NetBSD: cgram.c,v 1.12 2021/02/22 16:28:20 rillig Exp $");
 #endif
 
 #include <assert.h>
@@ -227,7 +227,8 @@
        for (int i = 0; i < extent_y; i++)
                extent_x = imax(extent_x, (int)lines.v[i].len);
 
-       pclose(f);
+       if (pclose(f) != 0)
+               exit(1); /* error message must come from child process */
 }
 
 static void