/* Time inconsistency check test
 *              by: john stultz (johnstul@us.ibm.com)
 *              (C) Copyright IBM 2003, 2004, 2005, 2012
 *              (C) Copyright Linaro Limited 2015
 *              Licensed under the GPLv2
 *
 *  To build:
 *      $ gcc inconsistency-check.c -o inconsistency-check -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 <time.h>
#include <sys/time.h>
#include <sys/timex.h>
#include <string.h>
#include <signal.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

#define CALLS_PER_LOOP 64
#define NSEC_PER_SEC 1000000000ULL

#define CLOCK_REALTIME                  0
#define CLOCK_MONOTONIC                 1
#define CLOCK_PROCESS_CPUTIME_ID        2
#define CLOCK_THREAD_CPUTIME_ID         3
#define CLOCK_MONOTONIC_RAW             4
#define CLOCK_REALTIME_COARSE           5
#define CLOCK_MONOTONIC_COARSE          6
#define CLOCK_BOOTTIME                  7
#define CLOCK_REALTIME_ALARM            8
#define CLOCK_BOOTTIME_ALARM            9
#define CLOCK_HWSPECIFIC                10
#define CLOCK_TAI                       11
#define NR_CLOCKIDS                     12

char *clockstring(int clockid)
{
        switch (clockid) {
        case CLOCK_REALTIME:
                return "CLOCK_REALTIME";
        case CLOCK_MONOTONIC:
                return "CLOCK_MONOTONIC";
        case CLOCK_PROCESS_CPUTIME_ID:
                return "CLOCK_PROCESS_CPUTIME_ID";
        case CLOCK_THREAD_CPUTIME_ID:
                return "CLOCK_THREAD_CPUTIME_ID";
        case CLOCK_MONOTONIC_RAW:
                return "CLOCK_MONOTONIC_RAW";
        case CLOCK_REALTIME_COARSE:
                return "CLOCK_REALTIME_COARSE";
        case CLOCK_MONOTONIC_COARSE:
                return "CLOCK_MONOTONIC_COARSE";
        case CLOCK_BOOTTIME:
                return "CLOCK_BOOTTIME";
        case CLOCK_REALTIME_ALARM:
                return "CLOCK_REALTIME_ALARM";
        case CLOCK_BOOTTIME_ALARM:
                return "CLOCK_BOOTTIME_ALARM";
        case CLOCK_TAI:
                return "CLOCK_TAI";
        };
        return "UNKNOWN_CLOCKID";
}

/* returns 1 if a <= b, 0 otherwise */
static inline int in_order(struct timespec a, struct timespec b)
{
        /* use unsigned to avoid false positives on 2038 rollover */
        if ((unsigned long)a.tv_sec < (unsigned long)b.tv_sec)
                return 1;
        if ((unsigned long)a.tv_sec > (unsigned long)b.tv_sec)
                return 0;
        if (a.tv_nsec > b.tv_nsec)
                return 0;
        return 1;
}



int consistency_test(int clock_type, unsigned long seconds)
{
        struct timespec list[CALLS_PER_LOOP];
        int i, inconsistent;
        long now, then;
        time_t t;
        char *start_str;

        clock_gettime(clock_type, &list[0]);
        now = then = list[0].tv_sec;

        /* timestamp start of test */
        t = time(0);
        start_str = ctime(&t);

        while (seconds == -1 || now - then < seconds) {
                inconsistent = 0;

                /* Fill list */
                for (i = 0; i < CALLS_PER_LOOP; i++)
                        clock_gettime(clock_type, &list[i]);

                /* Check for inconsistencies */
                for (i = 0; i < CALLS_PER_LOOP - 1; i++)
                        if (!in_order(list[i], list[i+1]))
                                inconsistent = i;

                /* display inconsistency */
                if (inconsistent) {
                        unsigned long long delta;

                        printf("\%s\n", start_str);
                        for (i = 0; i < CALLS_PER_LOOP; i++) {
                                if (i == inconsistent)
                                        printf("--------------------\n");
                                printf("%lu:%lu\n", list[i].tv_sec,
                                                        list[i].tv_nsec);
                                if (i == inconsistent + 1)
                                        printf("--------------------\n");
                        }
                        delta = list[inconsistent].tv_sec * NSEC_PER_SEC;
                        delta += list[inconsistent].tv_nsec;
                        delta -= list[inconsistent+1].tv_sec * NSEC_PER_SEC;
                        delta -= list[inconsistent+1].tv_nsec;
                        printf("Delta: %llu ns\n", delta);
                        fflush(0);
                        /* timestamp inconsistency*/
                        t = time(0);
                        printf("%s\n", ctime(&t));
                        printf("[FAILED]\n");
                        return -1;
                }
                now = list[0].tv_sec;
        }
        printf("[OK]\n");
        return 0;
}


int main(int argc, char *argv[])
{
        int clockid, opt;
        int userclock = CLOCK_REALTIME;
        int maxclocks = NR_CLOCKIDS;
        int runtime = 10;
        struct timespec ts;

        /* Process arguments */
        while ((opt = getopt(argc, argv, "t:c:")) != -1) {
                switch (opt) {
                case 't':
                        runtime = atoi(optarg);
                        break;
                case 'c':
                        userclock = atoi(optarg);
                        maxclocks = userclock + 1;
                        break;
                default:
                        printf("Usage: %s [-t <secs>] [-c <clockid>]\n", argv[0]);
                        printf("        -t: Number of seconds to run\n");
                        printf("        -c: clockid to use (default, all clockids)\n");
                        exit(-1);
                }
        }

        setbuf(stdout, NULL);

        for (clockid = userclock; clockid < maxclocks; clockid++) {

                if (clockid == CLOCK_HWSPECIFIC)
                        continue;

                if (!clock_gettime(clockid, &ts)) {
                        printf("Consistent %-30s ", clockstring(clockid));
                        if (consistency_test(clockid, runtime))
                                return ksft_exit_fail();
                }
        }
        return ksft_exit_pass();
}