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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
ksft_exit_pass(void)40 static inline int ksft_exit_pass(void)
41 {
42 	exit(0);
43 }
ksft_exit_fail(void)44 static inline int ksft_exit_fail(void)
45 {
46 	exit(1);
47 }
48 #endif
49 
50 
get_clocksources(char list[][30])51 int 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 
get_cur_clocksource(char * buf,size_t size)86 int 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 
change_clocksource(char * clocksource)97 int change_clocksource(char *clocksource)
98 {
99 	int fd;
100 	ssize_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 
run_tests(int secs)117 int 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 
131 char clocksource_list[10][30];
132 
main(int argv,char ** argc)133 int 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 			}
173 out:
174 	change_clocksource(orig_clk);
175 
176 	if (status)
177 		return ksft_exit_fail();
178 	return ksft_exit_pass();
179 }
180