tools/testing/selftests/timers/change_skew.c

   1 /* ADJ_FREQ Skew 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 cranks the ADJ_FREQ knob and
   7  *  then uses other tests to detect problems. Thus this test requires
   8  *  that the raw_skew, inconsistency-check and nanosleep tests be
   9  *  present in the same directory it is run from.
  10  *
  11  *  To build:
  12  *      $ gcc change_skew.c -o change_skew -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 <stdlib.h>
  28 #include <sys/time.h>
  29 #include <sys/timex.h>
  30 #include <time.h>
  31 #include "../kselftest.h"
  32
  33 #define NSEC_PER_SEC 1000000000LL
  34
  35
  36 int change_skew_test(int ppm)
  37 {
  38         struct timex tx;
  39         int ret;
  40
  41         tx.modes = ADJ_FREQUENCY;
  42         tx.freq = ppm << 16;
  43
  44         ret = adjtimex(&tx);
  45         if (ret < 0) {
  46                 printf("Error adjusting freq\n");
  47                 return ret;
  48         }
  49
  50         ret = system("./raw_skew");
  51         ret |= system("./inconsistency-check");
  52         ret |= system("./nanosleep");
  53
  54         return ret;
  55 }
  56
  57
  58 int main(int argv, char **argc)
  59 {
  60         struct timex tx;
  61         int i, ret;
  62
  63         int ppm[5] = {0, 250, 500, -250, -500};
  64
  65         /* Kill ntpd */
  66         ret = system("killall -9 ntpd");
  67
  68         /* Make sure there's no offset adjustment going on */
  69         tx.modes = ADJ_OFFSET;
  70         tx.offset = 0;
  71         ret = adjtimex(&tx);
  72
  73         if (ret < 0) {
  74                 printf("Maybe you're not running as root?\n");
  75                 return -1;
  76         }
  77
  78         for (i = 0; i < 5; i++) {
  79                 printf("Using %i ppm adjustment\n", ppm[i]);
  80                 ret = change_skew_test(ppm[i]);
  81                 if (ret)
  82                         break;
  83         }
  84
  85         /* Set things back */
  86         tx.modes = ADJ_FREQUENCY;
  87         tx.offset = 0;
  88         adjtimex(&tx);
  89
  90         if (ret) {
  91                 printf("[FAIL]");
  92                 return ksft_exit_fail();
  93         }
  94         printf("[OK]");
  95         return ksft_exit_pass();
  96 }