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
 40int 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
 75int 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
 86int 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
106int 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
120char clocksource_list[10][30];
121
122int 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			}
183out:
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}