time: Add gmtime/gmtime_r tests

Checked on x86_64-linux-gnu and i686-linux-gnu.

Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>

2 files changed, 125 insertions, 1 deletions

diff --git a/time/Makefile b/time/Makefile
index 91cb02a003..a503297527 100644
--- a/time/Makefile
+++ b/time/Makefile
@@ -49,7 +49,7 @@ tests	:= test_time clocktest tst-posixtz tst-strptime tst_wcsftime \
 	   tst-tzname tst-y2039 bug-mktime4 tst-strftime2 tst-strftime3 \
 	   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-settimeofday tst-itimer tst-gmtime
 
 include ../Rules
 
diff --git a/time/tst-gmtime.c b/time/tst-gmtime.c
new file mode 100644
index 0000000000..976f7c93ca
--- /dev/null
+++ b/time/tst-gmtime.c
@@ -0,0 +1,124 @@
+/* Basic tests for gmtime.
+   Copyright (C) 2021 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 <support/check.h>
+
+static int
+do_test (void)
+{
+  /* Check if the epoch time can be converted.  */
+  {
+    time_t t = 0;
+    struct tm *tmg = gmtime (&t);
+    TEST_COMPARE (tmg->tm_sec,   0);
+    TEST_COMPARE (tmg->tm_min,   0);
+    TEST_COMPARE (tmg->tm_hour,  0);
+    TEST_COMPARE (tmg->tm_mday,  1);
+    TEST_COMPARE (tmg->tm_mon,   0);
+    TEST_COMPARE (tmg->tm_year,  70);
+    TEST_COMPARE (tmg->tm_wday,  4);
+    TEST_COMPARE (tmg->tm_yday,  0);
+    TEST_COMPARE (tmg->tm_isdst, 0);
+  }
+  {
+    /* Same as before but with gmtime_r.  */
+    time_t t = 0;
+    struct tm tms;
+    struct tm *tmg = gmtime_r (&t, &tms);
+    TEST_VERIFY (tmg == &tms);
+    TEST_COMPARE (tmg->tm_sec,   0);
+    TEST_COMPARE (tmg->tm_min,   0);
+    TEST_COMPARE (tmg->tm_hour,  0);
+    TEST_COMPARE (tmg->tm_mday,  1);
+    TEST_COMPARE (tmg->tm_mon,   0);
+    TEST_COMPARE (tmg->tm_year,  70);
+    TEST_COMPARE (tmg->tm_wday,  4);
+    TEST_COMPARE (tmg->tm_yday,  0);
+    TEST_COMPARE (tmg->tm_isdst, 0);
+  }
+
+  /* Check if the max time value for 32 bit time_t can be converted.  */
+  {
+    time_t t = 0x7fffffff;
+    struct tm *tmg = gmtime (&t);
+    TEST_COMPARE (tmg->tm_sec,   7);
+    TEST_COMPARE (tmg->tm_min,   14);
+    TEST_COMPARE (tmg->tm_hour,  3);
+    TEST_COMPARE (tmg->tm_mday,  19);
+    TEST_COMPARE (tmg->tm_mon,   0);
+    TEST_COMPARE (tmg->tm_year,  138);
+    TEST_COMPARE (tmg->tm_wday,  2);
+    TEST_COMPARE (tmg->tm_yday,  18);
+    TEST_COMPARE (tmg->tm_isdst, 0);
+  }
+  {
+    /* Same as before but with ctime_r.  */
+    time_t t = 0x7fffffff;
+    struct tm tms;
+    struct tm *tmg = gmtime_r (&t, &tms);
+    TEST_VERIFY (tmg == &tms);
+    TEST_COMPARE (tmg->tm_sec,   7);
+    TEST_COMPARE (tmg->tm_min,   14);
+    TEST_COMPARE (tmg->tm_hour,  3);
+    TEST_COMPARE (tmg->tm_mday,  19);
+    TEST_COMPARE (tmg->tm_mon,   0);
+    TEST_COMPARE (tmg->tm_year,  138);
+    TEST_COMPARE (tmg->tm_wday,  2);
+    TEST_COMPARE (tmg->tm_yday,  18);
+    TEST_COMPARE (tmg->tm_isdst, 0);
+  }
+
+  if (sizeof (time_t) < 8)
+    return 0;
+
+  {
+    time_t t = (time_t) 0x80000000ull;
+    struct tm *tmg = gmtime (&t);
+    TEST_COMPARE (tmg->tm_sec,   8);
+    TEST_COMPARE (tmg->tm_min,   14);
+    TEST_COMPARE (tmg->tm_hour,  3);
+    TEST_COMPARE (tmg->tm_mday,  19);
+    TEST_COMPARE (tmg->tm_mon,   0);
+    TEST_COMPARE (tmg->tm_year,  138);
+    TEST_COMPARE (tmg->tm_wday,  2);
+    TEST_COMPARE (tmg->tm_yday,  18);
+    TEST_COMPARE (tmg->tm_isdst, 0);
+  }
+
+  {
+    time_t t = (time_t) 0x80000000ull;
+    struct tm tms;
+    struct tm *tmg = gmtime_r (&t, &tms);
+    TEST_VERIFY (tmg == &tms);
+    TEST_COMPARE (tmg->tm_sec,   8);
+    TEST_COMPARE (tmg->tm_min,   14);
+    TEST_COMPARE (tmg->tm_hour,  3);
+    TEST_COMPARE (tmg->tm_mday,  19);
+    TEST_COMPARE (tmg->tm_mon,   0);
+    TEST_COMPARE (tmg->tm_year,  138);
+    TEST_COMPARE (tmg->tm_wday,  2);
+    TEST_COMPARE (tmg->tm_yday,  18);
+    TEST_COMPARE (tmg->tm_isdst, 0);
+  }
+
+  return 0;
+}
+
+#include <support/test-driver.c>