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Date: Sun, 6 Nov 2011 18:00:22 +0200
From: Gleb Natapov <gleb@redhat.com>
Message-ID: <20111106160022.GF3225@redhat.com>
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Subject: [Qemu-devel] [PATCH] qemu_timedate_diff() shouldn't modify its
	argument.
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To: qemu-devel@nongnu.org

The caller of qemu_timedate_diff() does not expect that tm it passes to
the function will be modified, but mktime() is destructive and modifies
its argument. Pass a copy of tm to it and set tm_isdst so that mktime()
will not rely on it since its value may be outdated.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
diff --git a/vl.c b/vl.c
index 624da0f..641629b 100644
--- a/vl.c
+++ b/vl.c
@@ -460,8 +460,11 @@ int qemu_timedate_diff(struct tm *tm)
     if (rtc_date_offset == -1)
         if (rtc_utc)
             seconds = mktimegm(tm);
-        else
-            seconds = mktime(tm);
+        else {
+            struct tm tmp = *tm;
+            tmp.tm_isdst = -1; /* use timezone to figure it out */
+            seconds = mktime(&tmp);
+	}
     else
         seconds = mktimegm(tm) + rtc_date_offset;
 
--
			Gleb.