linux/tools/testing/selftests/timers/clocksource-switch.c

180 lines
3.5 KiB
C

/* Clocksource change test
* by: john stultz (johnstul@us.ibm.com)
* (C) Copyright IBM 2012
* Licensed under the GPLv2
*
* NOTE: This is a meta-test which quickly changes the clocksourc and
* then uses other tests to detect problems. Thus this test requires
* that the inconsistency-check and nanosleep tests be present in the
* same directory it is run from.
*
* To build:
* $ gcc clocksource-switch.c -o clocksource-switch -lrt
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/time.h>
#include <sys/timex.h>
#include <time.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <string.h>
#include <sys/wait.h>
#ifdef KTEST
#include "../kselftest.h"
#else
static inline int ksft_exit_pass(void)
{
exit(0);
}
static inline int ksft_exit_fail(void)
{
exit(1);
}
#endif
int get_clocksources(char list[][30])
{
int fd, i;
size_t size;
char buf[512];
char *head, *tmp;
fd = open("/sys/devices/system/clocksource/clocksource0/available_clocksource", O_RDONLY);
size = read(fd, buf, 512);
close(fd);
for (i = 0; i < 30; i++)
list[i][0] = '\0';
head = buf;
i = 0;
while (head - buf < size) {
/* Find the next space */
for (tmp = head; *tmp != ' '; tmp++) {
if (*tmp == '\n')
break;
if (*tmp == '\0')
break;
}
*tmp = '\0';
strcpy(list[i], head);
head = tmp + 1;
i++;
}
return i-1;
}
int get_cur_clocksource(char *buf, size_t size)
{
int fd;
fd = open("/sys/devices/system/clocksource/clocksource0/current_clocksource", O_RDONLY);
size = read(fd, buf, size);
return 0;
}
int change_clocksource(char *clocksource)
{
int fd;
size_t size;
fd = open("/sys/devices/system/clocksource/clocksource0/current_clocksource", O_WRONLY);
if (fd < 0)
return -1;
size = write(fd, clocksource, strlen(clocksource));
if (size < 0)
return -1;
close(fd);
return 0;
}
int run_tests(int secs)
{
int ret;
char buf[255];
sprintf(buf, "./inconsistency-check -t %i", secs);
ret = system(buf);
if (ret)
return ret;
ret = system("./nanosleep");
return ret;
}
char clocksource_list[10][30];
int main(int argv, char **argc)
{
char orig_clk[512];
int count, i, status;
pid_t pid;
get_cur_clocksource(orig_clk, 512);
count = get_clocksources(clocksource_list);
if (change_clocksource(clocksource_list[0])) {
printf("Error: You probably need to run this as root\n");
return -1;
}
/* Check everything is sane before we start switching asyncrhonously */
for (i = 0; i < count; i++) {
printf("Validating clocksource %s\n", clocksource_list[i]);
if (change_clocksource(clocksource_list[i])) {
status = -1;
goto out;
}
if (run_tests(5)) {
status = -1;
goto out;
}
}
printf("Running Asyncrhonous Switching Tests...\n");
pid = fork();
if (!pid)
return run_tests(60);
while (pid != waitpid(pid, &status, WNOHANG))
for (i = 0; i < count; i++)
if (change_clocksource(clocksource_list[i])) {
status = -1;
goto out;
}
out:
change_clocksource(orig_clk);
if (status)
return ksft_exit_fail();
return ksft_exit_pass();
}