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 clocksource 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 <fcntl.h>
27 #include <stdio.h>
28 #include <stdlib.h>
29 #include <string.h>
30 #include <sys/stat.h>
31 #include <sys/time.h>
32 #include <sys/timex.h>
33 #include <sys/types.h>
34 #include <sys/wait.h>
35 #include <time.h>
36 #include <unistd.h>
37 #include "../kselftest.h"
38
39
get_clocksources(char list[][30])40 int get_clocksources(char list[][30])
41 {
42 int fd, i;
43 size_t size;
44 char buf[512];
45 char *head, *tmp;
46
47 fd = open("/sys/devices/system/clocksource/clocksource0/available_clocksource", O_RDONLY);
48
49 size = read(fd, buf, 512);
50
51 close(fd);
52
53 for (i = 0; i < 10; i++)
54 list[i][0] = '\0';
55
56 head = buf;
57 i = 0;
58 while (head - buf < size) {
59 /* Find the next space */
60 for (tmp = head; *tmp != ' '; tmp++) {
61 if (*tmp == '\n')
62 break;
63 if (*tmp == '\0')
64 break;
65 }
66 *tmp = '\0';
67 strcpy(list[i], head);
68 head = tmp + 1;
69 i++;
70 }
71
72 return i-1;
73 }
74
get_cur_clocksource(char * buf,size_t size)75 int get_cur_clocksource(char *buf, size_t size)
76 {
77 int fd;
78
79 fd = open("/sys/devices/system/clocksource/clocksource0/current_clocksource", O_RDONLY);
80
81 size = read(fd, buf, size);
82
83 return 0;
84 }
85
change_clocksource(char * clocksource)86 int change_clocksource(char *clocksource)
87 {
88 int fd;
89 ssize_t size;
90
91 fd = open("/sys/devices/system/clocksource/clocksource0/current_clocksource", O_WRONLY);
92
93 if (fd < 0)
94 return -1;
95
96 size = write(fd, clocksource, strlen(clocksource));
97
98 if (size < 0)
99 return -1;
100
101 close(fd);
102 return 0;
103 }
104
105
run_tests(int secs)106 int run_tests(int secs)
107 {
108 int ret;
109 char buf[255];
110
111 sprintf(buf, "./inconsistency-check -t %i", secs);
112 ret = system(buf);
113 if (WIFEXITED(ret) && WEXITSTATUS(ret))
114 return WEXITSTATUS(ret);
115 ret = system("./nanosleep");
116 return WIFEXITED(ret) ? WEXITSTATUS(ret) : 0;
117 }
118
119
120 char clocksource_list[10][30];
121
main(int argc,char ** argv)122 int main(int argc, char **argv)
123 {
124 char orig_clk[512];
125 int count, i, status, opt;
126 int do_sanity_check = 1;
127 int runtime = 60;
128 pid_t pid;
129
130 /* Process arguments */
131 while ((opt = getopt(argc, argv, "st:")) != -1) {
132 switch (opt) {
133 case 's':
134 do_sanity_check = 0;
135 break;
136 case 't':
137 runtime = atoi(optarg);
138 break;
139 default:
140 printf("Usage: %s [-s] [-t <secs>]\n", argv[0]);
141 printf(" -s: skip sanity checks\n");
142 printf(" -t: Number of seconds to run\n");
143 exit(-1);
144 }
145 }
146
147 get_cur_clocksource(orig_clk, 512);
148
149 count = get_clocksources(clocksource_list);
150
151 if (change_clocksource(clocksource_list[0])) {
152 printf("Error: You probably need to run this as root\n");
153 return -1;
154 }
155
156 /* Check everything is sane before we start switching asynchronously */
157 if (do_sanity_check) {
158 for (i = 0; i < count; i++) {
159 printf("Validating clocksource %s\n",
160 clocksource_list[i]);
161 if (change_clocksource(clocksource_list[i])) {
162 status = -1;
163 goto out;
164 }
165 if (run_tests(5)) {
166 status = -1;
167 goto out;
168 }
169 }
170 }
171
172 printf("Running Asynchronous Switching Tests...\n");
173 pid = fork();
174 if (!pid)
175 return run_tests(runtime);
176
177 while (pid != waitpid(pid, &status, WNOHANG))
178 for (i = 0; i < count; i++)
179 if (change_clocksource(clocksource_list[i])) {
180 status = -1;
181 goto out;
182 }
183 out:
184 change_clocksource(orig_clk);
185
186 /* Print at the end to not mix output with child process */
187 ksft_print_header();
188 ksft_set_plan(1);
189 ksft_test_result(!status, "clocksource-switch\n");
190 ksft_exit(!status);
191 }
192