1 /* Set tai offset
2  *              by: John Stultz <john.stultz@linaro.org>
3  *              (C) Copyright Linaro 2013
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_tai(int offset)
40 {
41 	struct timex tx;
42 
43 	memset(&tx, 0, sizeof(tx));
44 
45 	tx.modes = ADJ_TAI;
46 	tx.constant = offset;
47 
48 	return adjtimex(&tx);
49 }
50 
51 int get_tai(void)
52 {
53 	struct timex tx;
54 
55 	memset(&tx, 0, sizeof(tx));
56 
57 	adjtimex(&tx);
58 	return tx.tai;
59 }
60 
61 int main(int argc, char **argv)
62 {
63 	int i, ret;
64 
65 	ret = get_tai();
66 	printf("tai offset started at %i\n", ret);
67 
68 	printf("Checking tai offsets can be properly set: ");
69 	for (i = 1; i <= 60; i++) {
70 		ret = set_tai(i);
71 		ret = get_tai();
72 		if (ret != i) {
73 			printf("[FAILED] expected: %i got %i\n", i, ret);
74 			return ksft_exit_fail();
75 		}
76 	}
77 	printf("[OK]\n");
78 	return ksft_exit_pass();
79 }
80