[BZ #2821]

	* time/mktime.c (guess_time_tm): Fix overflow detection.
	* time/Makefile (tests): Add bug-mktime1.
	* time/bug-mktime1.c: New file.

ChangeLog

@@ -1,5 +1,10 @@
 2006-09-09  Ulrich Drepper  <drepper@redhat.com>
 
+	[BZ #2821]
+	* time/mktime.c (guess_time_tm): Fix overflow detection.
+	* time/Makefile (tests): Add bug-mktime1.
+	* time/bug-mktime1.c: New file.
+
 	[BZ #3189, #3188]
 	* misc/sys/mman.h (remap_file_pages): Make available for _GNU_SOURCE.
 	(mremap): Likewise.

time/Makefile

@@ -35,7 +35,7 @@ distribute := datemsk
 
 tests	:= test_time clocktest tst-posixtz tst-strptime tst_wcsftime \
 	   tst-getdate tst-mktime tst-mktime2 tst-ftime_l tst-strftime \
-	   tst-mktime3 tst-strptime2 bug-asctime bug-asctime_r
+	   tst-mktime3 tst-strptime2 bug-asctime bug-asctime_r bug-mktime1
 
 include ../Rules
 

time/bug-mktime1.c

@@ -0,0 +1,17 @@
+#include <stdio.h>
+#include <time.h>
+
+
+static int
+do_test (void)
+{
+  struct tm t2 = { 0, 0, 0, 1, 1, 2050 - 1900, 1, 1, 1 };
+  time_t tt2 = mktime (&t2);
+  printf ("%ld\n", (long int) tt2);
+  if (sizeof (time_t) == 4 && tt2 != -1)
+    return 1;
+  return 0;
+}
+
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"

time/mktime.c

@@ -1,7 +1,7 @@
 /* Convert a `struct tm' to a time_t value.
-   Copyright (C) 1993-1999, 2002-2004, 2005 Free Software Foundation, Inc.
+   Copyright (C) 1993-1999, 2002-2005, 2006 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
-   Contributed by Paul Eggert (eggert@twinsun.com).
+   Contributed by Paul Eggert <eggert@twinsun.com>.
 
    The GNU C Library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
@@ -216,10 +216,11 @@ guess_time_tm (long int year, long int yday, int hour, int min, int sec,
   /* Overflow occurred one way or another.  Return the nearest result
      that is actually in range, except don't report a zero difference
      if the actual difference is nonzero, as that would cause a false
-     match.  */
+     match; and don't oscillate between two values, as that would
+     confuse the spring-forward gap detector.  */
   return (*t < TIME_T_MIDPOINT
-	  ? TIME_T_MIN + (*t == TIME_T_MIN)
-	  : TIME_T_MAX - (*t == TIME_T_MAX));
+	  ? (*t <= TIME_T_MIN + 1 ? *t + 1 : TIME_T_MIN)
+	  : (TIME_T_MAX - 1 <= *t ? *t - 1 : TIME_T_MAX));
 }
 
 /* Use CONVERT to convert *T to a broken down time in *TP.