zdump -v crashes with 64-bit time_t

[Ken Pizzini]

On Mon, Jun 14, 2004 at 11:51:48AM -0400, Olson, Arthur David (NIH/NCI) wrote:
> Here's a proposed change to zdump to avoid crashes when NULL is returned by
> asctime.
[...]
>   	if (v)
> ! 		(void) printf("%.24s UTC = ", asctime(gmtime(&t)));
>   	tmp = localtime(&t);
> ! 	(void) printf("%.24s", asctime(tmp));
...
>   	if (v)
> ! 		(void) printf("%.24s UTC = ", nonnull(asctime(gmtime(&t))));
>   	tmp = localtime(&t);
> ! 	(void) printf("%.24s", nonnull(asctime(tmp)));

That might work, depending on the local implementation of asctime(),
but I'd feel more comfortable with a patch that takes care to avoid
passing a NULL to asctime() in the first place.  Perhaps this patch
instead?
		--Ken Pizzini


--- zdump.c-orig	2004-03-02 06:52:38.000000000 -0800
+++ zdump.c	2004-06-14 20:05:19.453250080 -0700
@@ -1,4 +1,4 @@
-static char	elsieid[] = "@(#)zdump.c	7.31";
+static char	elsieid[] = "@(#)zdump.c	7.32";
 
 /*
 ** This code has been made independent of the rest of the time
@@ -334,6 +334,14 @@
 	return result;
 }
 
+static char *
+null_safe_asctime(t)
+const struct tm * t;
+{
+	static char null[] = "NULL";
+	return (t == NULL) ? null : asctime(t);
+}
+
 static void
 show(zone, t, v)
 char *	zone;
@@ -344,9 +352,9 @@
 
 	(void) printf("%-*s  ", (int) longest, zone);
 	if (v)
-		(void) printf("%.24s UTC = ", asctime(gmtime(&t)));
+		(void) printf("%.24s UTC = ", null_safe_asctime(gmtime(&t)));
 	tmp = localtime(&t);
-	(void) printf("%.24s", asctime(tmp));
+	(void) printf("%.24s", null_safe_asctime(tmp));
 	if (*abbr(tmp) != '\0')
 		(void) printf(" %s", abbr(tmp));
 	if (v) {