1/* Clocksource change test
2 *		by: john stultz (johnstul@us.ibm.com)
3 *		(C) Copyright IBM 2012
4 *		Licensed under the GPLv2
5 *
6 *  NOTE: This is a meta-test which quickly changes the clocksourc and
7 *  then uses other tests to detect problems. Thus this test requires
8 *  that the inconsistency-check and nanosleep tests be present in the
9 *  same directory it is run from.
10 *
11 *  To build:
12 *	$ gcc clocksource-switch.c -o clocksource-switch -lrt
13 *
14 *   This program is free software: you can redistribute it and/or modify
15 *   it under the terms of the GNU General Public License as published by
16 *   the Free Software Foundation, either version 2 of the License, or
17 *   (at your option) any later version.
18 *
19 *   This program is distributed in the hope that it will be useful,
20 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
21 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
22 *   GNU General Public License for more details.
23 */
24
25
26#include <stdio.h>
27#include <unistd.h>
28#include <stdlib.h>
29#include <sys/time.h>
30#include <sys/timex.h>
31#include <time.h>
32#include <sys/types.h>
33#include <sys/stat.h>
34#include <fcntl.h>
35#include <string.h>
36#include <sys/wait.h>
37#ifdef KTEST
38#include "../kselftest.h"
39#else
40static inline int ksft_exit_pass(void)
41{
42	exit(0);
43}
44static inline int ksft_exit_fail(void)
45{
46	exit(1);
47}
48#endif
49
50
51int get_clocksources(char list[][30])
52{
53	int fd, i;
54	size_t size;
55	char buf[512];
56	char *head, *tmp;
57
58	fd = open("/sys/devices/system/clocksource/clocksource0/available_clocksource", O_RDONLY);
59
60	size = read(fd, buf, 512);
61
62	close(fd);
63
64	for (i = 0; i < 30; i++)
65		list[i][0] = '\0';
66
67	head = buf;
68	i = 0;
69	while (head - buf < size) {
70		/* Find the next space */
71		for (tmp = head; *tmp != ' '; tmp++) {
72			if (*tmp == '\n')
73				break;
74			if (*tmp == '\0')
75				break;
76		}
77		*tmp = '\0';
78		strcpy(list[i], head);
79		head = tmp + 1;
80		i++;
81	}
82
83	return i-1;
84}
85
86int get_cur_clocksource(char *buf, size_t size)
87{
88	int fd;
89
90	fd = open("/sys/devices/system/clocksource/clocksource0/current_clocksource", O_RDONLY);
91
92	size = read(fd, buf, size);
93
94	return 0;
95}
96
97int change_clocksource(char *clocksource)
98{
99	int fd;
100	size_t size;
101
102	fd = open("/sys/devices/system/clocksource/clocksource0/current_clocksource", O_WRONLY);
103
104	if (fd < 0)
105		return -1;
106
107	size = write(fd, clocksource, strlen(clocksource));
108
109	if (size < 0)
110		return -1;
111
112	close(fd);
113	return 0;
114}
115
116
117int run_tests(int secs)
118{
119	int ret;
120	char buf[255];
121
122	sprintf(buf, "./inconsistency-check -t %i", secs);
123	ret = system(buf);
124	if (ret)
125		return ret;
126	ret = system("./nanosleep");
127	return ret;
128}
129
130
131char clocksource_list[10][30];
132
133int main(int argv, char **argc)
134{
135	char orig_clk[512];
136	int count, i, status;
137	pid_t pid;
138
139	get_cur_clocksource(orig_clk, 512);
140
141	count = get_clocksources(clocksource_list);
142
143	if (change_clocksource(clocksource_list[0])) {
144		printf("Error: You probably need to run this as root\n");
145		return -1;
146	}
147
148	/* Check everything is sane before we start switching asyncrhonously */
149	for (i = 0; i < count; i++) {
150		printf("Validating clocksource %s\n", clocksource_list[i]);
151		if (change_clocksource(clocksource_list[i])) {
152			status = -1;
153			goto out;
154		}
155		if (run_tests(5)) {
156			status = -1;
157			goto out;
158		}
159	}
160
161
162	printf("Running Asyncrhonous Switching Tests...\n");
163	pid = fork();
164	if (!pid)
165		return run_tests(60);
166
167	while (pid != waitpid(pid, &status, WNOHANG))
168		for (i = 0; i < count; i++)
169			if (change_clocksource(clocksource_list[i])) {
170				status = -1;
171				goto out;
172			}
173out:
174	change_clocksource(orig_clk);
175
176	if (status)
177		return ksft_exit_fail();
178	return ksft_exit_pass();
179}
180