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 
28 int 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 
38 int 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 
48 int 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 
58 int 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 	for (i = -15*60; i < 15*60; i += 30) {
69 		ret = set_tz(i, dst);
70 		ret = get_tz_min();
71 		if (ret != i) {
72 			printf("[FAILED] expected: %i got %i\n", i, ret);
73 			goto err;
74 		}
75 	}
76 	printf("[OK]\n");
77 
78 	printf("Checking invalid tz_minuteswest values are caught: ");
79 
80 	if (!set_tz(-15*60-1, dst)) {
81 		printf("[FAILED] %i didn't return failure!\n", -15*60-1);
82 		goto err;
83 	}
84 
85 	if (!set_tz(15*60+1, dst)) {
86 		printf("[FAILED] %i didn't return failure!\n", 15*60+1);
87 		goto err;
88 	}
89 
90 	if (!set_tz(-24*60, dst)) {
91 		printf("[FAILED] %i didn't return failure!\n", -24*60);
92 		goto err;
93 	}
94 
95 	if (!set_tz(24*60, dst)) {
96 		printf("[FAILED] %i didn't return failure!\n", 24*60);
97 		goto err;
98 	}
99 
100 	printf("[OK]\n");
101 
102 	set_tz(min, dst);
103 	return ksft_exit_pass();
104 
105 err:
106 	set_tz(min, dst);
107 	return ksft_exit_fail();
108 }
109