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 #ifdef KTEST
27 #include "../kselftest.h"
28 #else
29 static inline int ksft_exit_pass(void)
30 {
31 	exit(0);
32 }
33 static inline int ksft_exit_fail(void)
34 {
35 	exit(1);
36 }
37 #endif
38 
39 int set_tz(int min, int dst)
40 {
41 	struct timezone tz;
42 
43 	tz.tz_minuteswest = min;
44 	tz.tz_dsttime = dst;
45 
46 	return settimeofday(0, &tz);
47 }
48 
49 int get_tz_min(void)
50 {
51 	struct timezone tz;
52 	struct timeval tv;
53 
54 	memset(&tz, 0, sizeof(tz));
55 	gettimeofday(&tv, &tz);
56 	return tz.tz_minuteswest;
57 }
58 
59 int get_tz_dst(void)
60 {
61 	struct timezone tz;
62 	struct timeval tv;
63 
64 	memset(&tz, 0, sizeof(tz));
65 	gettimeofday(&tv, &tz);
66 	return tz.tz_dsttime;
67 }
68 
69 int main(int argc, char **argv)
70 {
71 	int i, ret;
72 	int min, dst;
73 
74 	min = get_tz_min();
75 	dst = get_tz_dst();
76 	printf("tz_minuteswest started at %i, dst at %i\n", min, dst);
77 
78 	printf("Checking tz_minuteswest can be properly set: ");
79 	for (i = -15*60; i < 15*60; i += 30) {
80 		ret = set_tz(i, dst);
81 		ret = get_tz_min();
82 		if (ret != i) {
83 			printf("[FAILED] expected: %i got %i\n", i, ret);
84 			goto err;
85 		}
86 	}
87 	printf("[OK]\n");
88 
89 	printf("Checking invalid tz_minuteswest values are caught: ");
90 
91 	if (!set_tz(-15*60-1, dst)) {
92 		printf("[FAILED] %i didn't return failure!\n", -15*60-1);
93 		goto err;
94 	}
95 
96 	if (!set_tz(15*60+1, dst)) {
97 		printf("[FAILED] %i didn't return failure!\n", 15*60+1);
98 		goto err;
99 	}
100 
101 	if (!set_tz(-24*60, dst)) {
102 		printf("[FAILED] %i didn't return failure!\n", -24*60);
103 		goto err;
104 	}
105 
106 	if (!set_tz(24*60, dst)) {
107 		printf("[FAILED] %i didn't return failure!\n", 24*60);
108 		goto err;
109 	}
110 
111 	printf("[OK]\n");
112 
113 	set_tz(min, dst);
114 	return ksft_exit_pass();
115 
116 err:
117 	set_tz(min, dst);
118 	return ksft_exit_fail();
119 }
120