Ensure we use gnulib mktime rather than glibc's mktime, on hosts

where mktime isn't the inverse of localtime (negative time_t).

1 files changed, 182 insertions, 2 deletions

diff --git a/m4/mktime.m4 b/m4/mktime.m4
index 94468eefa6..2131cff4fb 100644
--- a/m4/mktime.m4
+++ b/m4/mktime.m4
@@ -1,5 +1,5 @@
-# mktime.m4 serial 1
-dnl Copyright (C) 2002 Free Software Foundation, Inc.
+# mktime.m4 serial 2
+dnl Copyright (C) 2002, 2003 Free Software Foundation, Inc.
 dnl This file is free software, distributed under the terms of the GNU
 dnl General Public License.  As a special exception to the GNU General
 dnl Public License, this file may be distributed as part of a program
@@ -8,6 +8,186 @@ dnl the same distribution terms as the rest of that program.
 
 dnl From Jim Meyering.
 
+# Redefine AC_FUNC_MKTIME, to fix a bug in Autoconf 2.57 and earlier.
+# This redefinition can be removed once a new version of Autoconf comes out.
+# The redefinition is taken from
+# <http://savannah.gnu.org/cgi-bin/viewcvs/*checkout*/autoconf/autoconf/lib/autoconf/functions.m4?rev=1.78>.
+# AC_FUNC_MKTIME
+# --------------
+AC_DEFUN([AC_FUNC_MKTIME],
+[AC_REQUIRE([AC_HEADER_TIME])dnl
+AC_CHECK_HEADERS(stdlib.h sys/time.h unistd.h)
+AC_CHECK_FUNCS(alarm)
+AC_CACHE_CHECK([for working mktime], ac_cv_func_working_mktime,
+[AC_RUN_IFELSE([AC_LANG_SOURCE(
+[[/* Test program from Paul Eggert and Tony Leneis.  */
+#if TIME_WITH_SYS_TIME
+# include <sys/time.h>
+# include <time.h>
+#else
+# if HAVE_SYS_TIME_H
+#  include <sys/time.h>
+# else
+#  include <time.h>
+# endif
+#endif
+
+#if HAVE_STDLIB_H
+# include <stdlib.h>
+#endif
+
+#if HAVE_UNISTD_H
+# include <unistd.h>
+#endif
+
+#if !HAVE_ALARM
+# define alarm(X) /* empty */
+#endif
+
+/* Work around redefinition to rpl_putenv by other config tests.  */
+#undef putenv
+
+static time_t time_t_max;
+static time_t time_t_min;
+
+/* Values we'll use to set the TZ environment variable.  */
+static char *tz_strings[] = {
+  (char *) 0, "TZ=GMT0", "TZ=JST-9",
+  "TZ=EST+3EDT+2,M10.1.0/00:00:00,M2.3.0/00:00:00"
+};
+#define N_STRINGS (sizeof (tz_strings) / sizeof (tz_strings[0]))
+
+/* Fail if mktime fails to convert a date in the spring-forward gap.
+   Based on a problem report from Andreas Jaeger.  */
+static void
+spring_forward_gap ()
+{
+  /* glibc (up to about 1998-10-07) failed this test. */
+  struct tm tm;
+
+  /* Use the portable POSIX.1 specification "TZ=PST8PDT,M4.1.0,M10.5.0"
+     instead of "TZ=America/Vancouver" in order to detect the bug even
+     on systems that don't support the Olson extension, or don't have the
+     full zoneinfo tables installed.  */
+  putenv ("TZ=PST8PDT,M4.1.0,M10.5.0");
+
+  tm.tm_year = 98;
+  tm.tm_mon = 3;
+  tm.tm_mday = 5;
+  tm.tm_hour = 2;
+  tm.tm_min = 0;
+  tm.tm_sec = 0;
+  tm.tm_isdst = -1;
+  if (mktime (&tm) == (time_t)-1)
+    exit (1);
+}
+
+static void
+mktime_test1 (now)
+     time_t now;
+{
+  struct tm *lt;
+  if ((lt = localtime (&now)) && mktime (lt) != now)
+    exit (1);
+}
+
+static void
+mktime_test (now)
+     time_t now;
+{
+  mktime_test1 (now);
+  mktime_test1 ((time_t) (time_t_max - now));
+  mktime_test1 ((time_t) (time_t_min + now));
+}
+
+static void
+irix_6_4_bug ()
+{
+  /* Based on code from Ariel Faigon.  */
+  struct tm tm;
+  tm.tm_year = 96;
+  tm.tm_mon = 3;
+  tm.tm_mday = 0;
+  tm.tm_hour = 0;
+  tm.tm_min = 0;
+  tm.tm_sec = 0;
+  tm.tm_isdst = -1;
+  mktime (&tm);
+  if (tm.tm_mon != 2 || tm.tm_mday != 31)
+    exit (1);
+}
+
+static void
+bigtime_test (j)
+     int j;
+{
+  struct tm tm;
+  time_t now;
+  tm.tm_year = tm.tm_mon = tm.tm_mday = tm.tm_hour = tm.tm_min = tm.tm_sec = j;
+  now = mktime (&tm);
+  if (now != (time_t) -1)
+    {
+      struct tm *lt = localtime (&now);
+      if (! (lt
+	     && lt->tm_year == tm.tm_year
+	     && lt->tm_mon == tm.tm_mon
+	     && lt->tm_mday == tm.tm_mday
+	     && lt->tm_hour == tm.tm_hour
+	     && lt->tm_min == tm.tm_min
+	     && lt->tm_sec == tm.tm_sec
+	     && lt->tm_yday == tm.tm_yday
+	     && lt->tm_wday == tm.tm_wday
+	     && ((lt->tm_isdst < 0 ? -1 : 0 < lt->tm_isdst)
+		  == (tm.tm_isdst < 0 ? -1 : 0 < tm.tm_isdst))))
+	exit (1);
+    }
+}
+
+int
+main ()
+{
+  time_t t, delta;
+  int i, j;
+
+  /* This test makes some buggy mktime implementations loop.
+     Give up after 60 seconds; a mktime slower than that
+     isn't worth using anyway.  */
+  alarm (60);
+
+  for (time_t_max = 1; 0 < time_t_max; time_t_max *= 2)
+    continue;
+  time_t_max--;
+  if ((time_t) -1 < 0)
+    for (time_t_min = -1; (time_t) (time_t_min * 2) < 0; time_t_min *= 2)
+      continue;
+  delta = time_t_max / 997; /* a suitable prime number */
+  for (i = 0; i < N_STRINGS; i++)
+    {
+      if (tz_strings[i])
+	putenv (tz_strings[i]);
+
+      for (t = 0; t <= time_t_max - delta; t += delta)
+	mktime_test (t);
+      mktime_test ((time_t) 1);
+      mktime_test ((time_t) (60 * 60));
+      mktime_test ((time_t) (60 * 60 * 24));
+
+      for (j = 1; 0 < j; j *= 2)
+	bigtime_test (j);
+      bigtime_test (j - 1);
+    }
+  irix_6_4_bug ();
+  spring_forward_gap ();
+  exit (0);
+}]])],
+	       [ac_cv_func_working_mktime=yes],
+	       [ac_cv_func_working_mktime=no],
+	       [ac_cv_func_working_mktime=no])])
+if test $ac_cv_func_working_mktime = no; then
+  AC_LIBOBJ([mktime])
+fi
+])# AC_FUNC_MKTIME
+
 AC_DEFUN([gl_FUNC_MKTIME],
 [
   AC_REQUIRE([AC_FUNC_MKTIME])