[PATCH] mktime.c: normalize tp->tm_isdst value to -1/0/1.

[Jim Meyering]

Here's another from glibc:

>From 5490f5a9848076555e5cdac9b6613b9d107a6ac2 Mon Sep 17 00:00:00 2001
From: Ulrich Drepper <address@hidden>
Date: Wed, 23 Jul 2008 16:19:15 +0200
Subject: [PATCH] mktime.c: normalize tp->tm_isdst value to -1/0/1.

* lib/mktime.c (__mktime_internal): Normalize tp->tm_isdst value.
Reported by Michael Ringe <address@hidden> in
<http://sourceware.org/bugzilla/show_bug.cgi?id=6723>.
---
 ChangeLog    |    5 +++++
 lib/mktime.c |    4 +++-
 2 files changed, 8 insertions(+), 1 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 97f6c76..6c48308 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,10 @@
 2008-07-23  Ulrich Drepper  <address@hidden>

+       mktime.c: normalize tp->tm_isdst value to -1/0/1.
+       * lib/mktime.c (__mktime_internal): Normalize tp->tm_isdst value.
+       Reported by Michael Ringe <address@hidden> in
+       <http://sourceware.org/bugzilla/show_bug.cgi?id=6723>.
+
        * lib/canonicalize-lgpl.c (__realpath): Avoid buffer overflow after
        readlink on platforms without PATH_MAX.

diff --git a/lib/mktime.c b/lib/mktime.c
index a91fb20..f9e7b60 100644
--- a/lib/mktime.c
+++ b/lib/mktime.c
@@ -290,7 +290,9 @@ __mktime_internal (struct tm *tp,
   int mday = tp->tm_mday;
   int mon = tp->tm_mon;
   int year_requested = tp->tm_year;
-  int isdst = tp->tm_isdst;
+  /* Normalize the value.  */
+  int isdst = ((tp->tm_isdst >> (8 * sizeof (tp->tm_isdst) - 1))
+              | (tp->tm_isdst != 0));

   /* 1 if the previous probe was DST.  */
   int dst2;
--
1.6.0.rc0.16.g6458d