1/* Set tz value
2 * by: John Stultz <john.stultz@linaro.org>
3 * (C) Copyright Linaro 2016
4 * Licensed under the GPLv2
5 *
6 * This program is free software: you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation, either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 */
16
17
18#include <stdio.h>
19#include <stdlib.h>
20#include <time.h>
21#include <sys/time.h>
22#include <sys/timex.h>
23#include <string.h>
24#include <signal.h>
25#include <unistd.h>
26#include "../kselftest.h"
27
28int set_tz(int min, int dst)
29{
30 struct timezone tz;
31
32 tz.tz_minuteswest = min;
33 tz.tz_dsttime = dst;
34
35 return settimeofday(0, &tz);
36}
37
38int get_tz_min(void)
39{
40 struct timezone tz;
41 struct timeval tv;
42
43 memset(&tz, 0, sizeof(tz));
44 gettimeofday(&tv, &tz);
45 return tz.tz_minuteswest;
46}
47
48int get_tz_dst(void)
49{
50 struct timezone tz;
51 struct timeval tv;
52
53 memset(&tz, 0, sizeof(tz));
54 gettimeofday(&tv, &tz);
55 return tz.tz_dsttime;
56}
57
58int main(int argc, char **argv)
59{
60 int i, ret;
61 int min, dst;
62
63 min = get_tz_min();
64 dst = get_tz_dst();
65 printf("tz_minuteswest started at %i, dst at %i\n", min, dst);
66
67 printf("Checking tz_minuteswest can be properly set: ");
68 fflush(stdout);
69 for (i = -15*60; i < 15*60; i += 30) {
70 ret = set_tz(min: i, dst);
71 ret = get_tz_min();
72 if (ret != i) {
73 printf("[FAILED] expected: %i got %i\n", i, ret);
74 goto err;
75 }
76 }
77 printf("[OK]\n");
78
79 printf("Checking invalid tz_minuteswest values are caught: ");
80 fflush(stdout);
81
82 if (!set_tz(min: -15*60-1, dst)) {
83 printf("[FAILED] %i didn't return failure!\n", -15*60-1);
84 goto err;
85 }
86
87 if (!set_tz(min: 15*60+1, dst)) {
88 printf("[FAILED] %i didn't return failure!\n", 15*60+1);
89 goto err;
90 }
91
92 if (!set_tz(min: -24*60, dst)) {
93 printf("[FAILED] %i didn't return failure!\n", -24*60);
94 goto err;
95 }
96
97 if (!set_tz(min: 24*60, dst)) {
98 printf("[FAILED] %i didn't return failure!\n", 24*60);
99 goto err;
100 }
101
102 printf("[OK]\n");
103
104 set_tz(min, dst);
105 return ksft_exit_pass();
106
107err:
108 set_tz(min, dst);
109 return ksft_exit_fail();
110}
111

source code of linux/tools/testing/selftests/timers/set-tz.c