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

   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
  40static inline int ksft_exit_pass(void)
  41{
  42        exit(0);
  43}
  44static inline int ksft_exit_fail(void)
  45{
  46        exit(1);
  47}
  48#endif
  49
  50
  51int 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
  86int 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
  97int 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
 117int 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
 131char clocksource_list[10][30];
 132
 133int 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                        }
 173out:
 174        change_clocksource(orig_clk);
 175
 176        if (status)
 177                return ksft_exit_fail();
 178        return ksft_exit_pass();
 179}
 180