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#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 (ret)
 114                return ret;
 115        ret = system("./nanosleep");
 116        return ret;
 117}
 118
 119
 120char clocksource_list[10][30];
 121
 122int main(int argv, char **argc)
 123{
 124        char orig_clk[512];
 125        int count, i, status;
 126        pid_t pid;
 127
 128        get_cur_clocksource(orig_clk, 512);
 129
 130        count = get_clocksources(clocksource_list);
 131
 132        if (change_clocksource(clocksource_list[0])) {
 133                printf("Error: You probably need to run this as root\n");
 134                return -1;
 135        }
 136
 137        /* Check everything is sane before we start switching asyncrhonously */
 138        for (i = 0; i < count; i++) {
 139                printf("Validating clocksource %s\n", clocksource_list[i]);
 140                if (change_clocksource(clocksource_list[i])) {
 141                        status = -1;
 142                        goto out;
 143                }
 144                if (run_tests(5)) {
 145                        status = -1;
 146                        goto out;
 147                }
 148        }
 149
 150
 151        printf("Running Asynchronous Switching Tests...\n");
 152        pid = fork();
 153        if (!pid)
 154                return run_tests(60);
 155
 156        while (pid != waitpid(pid, &status, WNOHANG))
 157                for (i = 0; i < count; i++)
 158                        if (change_clocksource(clocksource_list[i])) {
 159                                status = -1;
 160                                goto out;
 161                        }
 162out:
 163        change_clocksource(orig_clk);
 164
 165        if (status)
 166                return ksft_exit_fail();
 167        return ksft_exit_pass();
 168}
 169