[PATCH] Use 64-bit time_t interfaces in strftime and strptime (bug 30053)

[Andreas Schwab <schwab@suse.de>]

Both functions use time_t only internally, so the ABI is not affected.
---
 time/Makefile           |  3 ++-
 time/strftime_l.c       |  4 ++++
 time/strptime_l.c       |  4 +++-
 time/tst-y2038-time64.c |  1 +
 time/tst-y2038.c        | 52 +++++++++++++++++++++++++++++++++++++++++
 5 files changed, 62 insertions(+), 2 deletions(-)
 create mode 100644 time/tst-y2038-time64.c
 create mode 100644 time/tst-y2038.c

diff --git a/time/Makefile b/time/Makefile
index d86f2105c5..8b2e1d2398 100644
--- a/time/Makefile
+++ b/time/Makefile
@@ -50,7 +50,7 @@ tests	:= test_time clocktest tst-posixtz tst-strptime tst_wcsftime \
 	   tst-clock tst-clock2 tst-clock_nanosleep tst-cpuclock1 \
 	   tst-adjtime tst-ctime tst-difftime tst-mktime4 tst-clock_settime \
 	   tst-settimeofday tst-itimer tst-gmtime tst-timegm \
-	   tst-timespec_get tst-timespec_getres
+	   tst-timespec_get tst-timespec_getres tst-y2038
 
 tests-time64 := \
   tst-adjtime-time64 \
@@ -68,6 +68,7 @@ tests-time64 := \
   tst-timegm-time64 \
   tst-timespec_get-time64 \
   tst-timespec_getres-time64 \
+  tst-y2038-time64 \
   tst-y2039-time64
 
 include ../Rules
diff --git a/time/strftime_l.c b/time/strftime_l.c
index e09561c39c..402c6c4111 100644
--- a/time/strftime_l.c
+++ b/time/strftime_l.c
@@ -159,6 +159,10 @@ extern char *tzname[];
 #ifdef _LIBC
 # define tzname __tzname
 # define tzset __tzset
+
+# define time_t __time64_t
+# define __gmtime_r(t, tp) __gmtime64_r (t, tp)
+# define mktime(tp) __mktime64 (tp)
 #endif
 
 #if !HAVE_TM_GMTOFF
diff --git a/time/strptime_l.c b/time/strptime_l.c
index 80fd705b8d..85c3249fcc 100644
--- a/time/strptime_l.c
+++ b/time/strptime_l.c
@@ -30,8 +30,10 @@
 #ifdef _LIBC
 # define HAVE_LOCALTIME_R 0
 # include "../locale/localeinfo.h"
-#endif
 
+# define time_t __time64_t
+# define __localtime_r(t, tp) __localtime64_r (t, tp)
+#endif
 
 #if ! HAVE_LOCALTIME_R && ! defined localtime_r
 # ifdef _LIBC
diff --git a/time/tst-y2038-time64.c b/time/tst-y2038-time64.c
new file mode 100644
index 0000000000..d6482b0be9
--- /dev/null
+++ b/time/tst-y2038-time64.c
@@ -0,0 +1 @@
+#include "tst-y2038.c"
diff --git a/time/tst-y2038.c b/time/tst-y2038.c
new file mode 100644
index 0000000000..659716d0fa
--- /dev/null
+++ b/time/tst-y2038.c
@@ -0,0 +1,52 @@
+/* Test strftime and strptime after 2038-01-19 03:14:07 UTC (bug 30053).
+   Copyright (C) 2023 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <time.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <support/check.h>
+
+static int
+do_test (void)
+{
+  TEST_VERIFY_EXIT (setenv ("TZ", "UTC0", 1) == 0);
+  tzset ();
+  if (sizeof (time_t) > 4)
+    {
+      time_t wrap = (time_t) 2147483648LL;
+      char buf[80];
+      struct tm *tm = gmtime (&wrap);
+      TEST_VERIFY_EXIT (tm != NULL);
+      TEST_VERIFY_EXIT (strftime (buf, sizeof buf, "%s", tm) > 0);
+      puts (buf);
+      TEST_VERIFY (strcmp (buf, "2147483648") == 0);
+
+      struct tm tm2;
+      char *p = strptime (buf, "%s", &tm2);
+      TEST_VERIFY_EXIT (p != NULL && *p == '\0');
+      time_t t = mktime (&tm2);
+      printf ("%lld\n", (long long) t);
+      TEST_VERIFY (t == wrap);
+    }
+  else
+    FAIL_UNSUPPORTED ("32-bit time_t");
+  return 0;
+}
+
+#include <support/test-driver.c>
-- 
2.39.1


-- 
Andreas Schwab, SUSE Labs, schwab@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE  1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."