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