kselftests: timers: Add set-tz test case

Mika Westerberg reported a erroneous change in the error
checking of settimeofday, so I wanted to add a test to ensure
we don't trip over this again.

Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: Baolin Wang <baolin.wang@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Shuah Khan <shuahkh@osg.samsung.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>

tools/testing/selftests/timers/Makefile

@@ -10,7 +10,7 @@ TEST_PROGS = posix_timers nanosleep nsleep-lat set-timer-lat mqueue-lat \
 
 TEST_PROGS_EXTENDED = alarmtimer-suspend valid-adjtimex adjtick change_skew \
 		      skew_consistency clocksource-switch leap-a-day \
-		      leapcrash set-tai set-2038
+		      leapcrash set-tai set-2038 set-tz
 
 bins = $(TEST_PROGS) $(TEST_PROGS_EXTENDED)
 
@@ -30,6 +30,7 @@ run_destructive_tests: run_tests
 	./clocksource-switch
 	./leap-a-day -s -i 10
 	./leapcrash
+	./set-tz
 	./set-tai
 	./set-2038
 

tools/testing/selftests/timers/set-tz.c

+/* Set tz value
+ *              by: John Stultz <john.stultz@linaro.org>
+ *              (C) Copyright Linaro 2016
+ *              Licensed under the GPLv2
+ *
+ *   This program is free software: you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, either version 2 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This program 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 General Public License for more details.
+ */
+
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+#include <sys/time.h>
+#include <sys/timex.h>
+#include <string.h>
+#include <signal.h>
+#include <unistd.h>
+#ifdef KTEST
+#include "../kselftest.h"
+#else
+static inline int ksft_exit_pass(void)
+{
+	exit(0);
+}
+static inline int ksft_exit_fail(void)
+{
+	exit(1);
+}
+#endif
+
+int set_tz(int min, int dst)
+{
+	struct timezone tz;
+
+	tz.tz_minuteswest = min;
+	tz.tz_dsttime = dst;
+
+	return settimeofday(0, &tz);
+}
+
+int get_tz_min(void)
+{
+	struct timezone tz;
+	struct timeval tv;
+
+	memset(&tz, 0, sizeof(tz));
+	gettimeofday(&tv, &tz);
+	return tz.tz_minuteswest;
+}
+
+int get_tz_dst(void)
+{
+	struct timezone tz;
+	struct timeval tv;
+
+	memset(&tz, 0, sizeof(tz));
+	gettimeofday(&tv, &tz);
+	return tz.tz_dsttime;
+}
+
+int main(int argc, char **argv)
+{
+	int i, ret;
+	int min, dst;
+
+	min = get_tz_min();
+	dst = get_tz_dst();
+	printf("tz_minuteswest started at %i, dst at %i\n", min, dst);
+
+	printf("Checking tz_minuteswest can be properly set: ");
+	for (i = -15*60; i < 15*60; i += 30) {
+		ret = set_tz(i, dst);
+		ret = get_tz_min();
+		if (ret != i) {
+			printf("[FAILED] expected: %i got %i\n", i, ret);
+			goto err;
+		}
+	}
+	printf("[OK]\n");
+
+	printf("Checking invalid tz_minuteswest values are caught: ");
+
+	if (!set_tz(-15*60-1, dst)) {
+		printf("[FAILED] %i didn't return failure!\n", -15*60-1);
+		goto err;
+	}
+
+	if (!set_tz(15*60+1, dst)) {
+		printf("[FAILED] %i didn't return failure!\n", 15*60+1);
+		goto err;
+	}
+
+	if (!set_tz(-24*60, dst)) {
+		printf("[FAILED] %i didn't return failure!\n", -24*60);
+		goto err;
+	}
+
+	if (!set_tz(24*60, dst)) {
+		printf("[FAILED] %i didn't return failure!\n", 24*60);
+		goto err;
+	}
+
+	printf("[OK]\n");
+
+	set_tz(min, dst);
+	return ksft_exit_pass();
+
+err:
+	set_tz(min, dst);
+	return ksft_exit_fail();
+}