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 #ifdef KTEST
  32 #include "../kselftest.h"
  33 #else
  34 static inline int ksft_exit_pass(void)
  35 {
  36         exit(0);
  37 }
  38 static inline int ksft_exit_fail(void)
  39 {
  40         exit(1);
  41 }
  42 #endif
  43
  44 #define NSEC_PER_SEC 1000000000LL
  45
  46
  47 int change_skew_test(int ppm)
  48 {
  49         struct timex tx;
  50         int ret;
  51
  52         tx.modes = ADJ_FREQUENCY;
  53         tx.freq = ppm << 16;
  54
  55         ret = adjtimex(&tx);
  56         if (ret < 0) {
  57                 printf("Error adjusting freq\n");
  58                 return ret;
  59         }
  60
  61         ret = system("./raw_skew");
  62         ret |= system("./inconsistency-check");
  63         ret |= system("./nanosleep");
  64
  65         return ret;
  66 }
  67
  68
  69 int main(int argv, char **argc)
  70 {
  71         struct timex tx;
  72         int i, ret;
  73
  74         int ppm[5] = {0, 250, 500, -250, -500};
  75
  76         /* Kill ntpd */
  77         ret = system("killall -9 ntpd");
  78
  79         /* Make sure there's no offset adjustment going on */
  80         tx.modes = ADJ_OFFSET;
  81         tx.offset = 0;
  82         ret = adjtimex(&tx);
  83
  84         if (ret < 0) {
  85                 printf("Maybe you're not running as root?\n");
  86                 return -1;
  87         }
  88
  89         for (i = 0; i < 5; i++) {
  90                 printf("Using %i ppm adjustment\n", ppm[i]);
  91                 ret = change_skew_test(ppm[i]);
  92                 if (ret)
  93                         break;
  94         }
  95
  96         /* Set things back */
  97         tx.modes = ADJ_FREQUENCY;
  98         tx.offset = 0;
  99         adjtimex(&tx);
 100
 101         if (ret) {
 102                 printf("[FAIL]");
 103                 return ksft_exit_fail();
 104         }
 105         printf("[OK]");
 106         return ksft_exit_pass();
 107 }