/* Clocksource change test
 *              by: john stultz (johnstul@us.ibm.com)
 *              (C) Copyright IBM 2012
 *              Licensed under the GPLv2
 *
 *  NOTE: This is a meta-test which quickly changes the clocksource and
 *  then uses other tests to detect problems. Thus this test requires
 *  that the inconsistency-check and nanosleep tests be present in the
 *  same directory it is run from.
 *
 *  To build:
 *      $ gcc clocksource-switch.c -o clocksource-switch -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 <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/timex.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <time.h>
#include <unistd.h>
#include "kselftest.h"


int get_clocksources(char list[][30])
{
        int fd, i;
        size_t size;
        char buf[512];
        char *head, *tmp;

        fd = open("/sys/devices/system/clocksource/clocksource0/available_clocksource", O_RDONLY);

        size = read(fd, buf, 512);

        close(fd);

        for (i = 0; i < 10; i++)
                list[i][0] = '\0';

        head = buf;
        i = 0;
        while (head - buf < size) {
                /* Find the next space */
                for (tmp = head; *tmp != ' '; tmp++) {
                        if (*tmp == '\n')
                                break;
                        if (*tmp == '\0')
                                break;
                }
                *tmp = '\0';
                strcpy(list[i], head);
                head = tmp + 1;
                i++;
        }

        return i-1;
}

int get_cur_clocksource(char *buf, size_t size)
{
        int fd;

        fd = open("/sys/devices/system/clocksource/clocksource0/current_clocksource", O_RDONLY);

        size = read(fd, buf, size);

        return 0;
}

int change_clocksource(char *clocksource)
{
        int fd;
        ssize_t size;

        fd = open("/sys/devices/system/clocksource/clocksource0/current_clocksource", O_WRONLY);

        if (fd < 0)
                return -1;

        size = write(fd, clocksource, strlen(clocksource));

        if (size < 0)
                return -1;

        close(fd);
        return 0;
}


int run_tests(int secs)
{
        int ret;
        char buf[255];

        sprintf(buf, "./inconsistency-check -t %i", secs);
        ret = system(buf);
        if (WIFEXITED(ret) && WEXITSTATUS(ret))
                return WEXITSTATUS(ret);
        ret = system("./nanosleep");
        return WIFEXITED(ret) ? WEXITSTATUS(ret) : 0;
}


char clocksource_list[10][30];

int main(int argc, char **argv)
{
        char orig_clk[512];
        int count, i, status, opt;
        int do_sanity_check = 1;
        int runtime = 60;
        pid_t pid;

        /* Process arguments */
        while ((opt = getopt(argc, argv, "st:")) != -1) {
                switch (opt) {
                case 's':
                        do_sanity_check = 0;
                        break;
                case 't':
                        runtime = atoi(optarg);
                        break;
                default:
                        printf("Usage: %s [-s] [-t <secs>]\n", argv[0]);
                        printf("        -s: skip sanity checks\n");
                        printf("        -t: Number of seconds to run\n");
                        exit(-1);
                }
        }

        get_cur_clocksource(orig_clk, 512);

        count = get_clocksources(clocksource_list);

        if (change_clocksource(clocksource_list[0])) {
                printf("Error: You probably need to run this as root\n");
                return -1;
        }

        /* Check everything is sane before we start switching asynchronously */
        if (do_sanity_check) {
                for (i = 0; i < count; i++) {
                        ksft_print_msg("Validating clocksource %s\n",
                                        clocksource_list[i]);
                        if (change_clocksource(clocksource_list[i])) {
                                status = -1;
                                goto out;
                        }
                        if (run_tests(5)) {
                                status = -1;
                                goto out;
                        }
                }
        }

        ksft_print_msg("Running Asynchronous Switching Tests...\n");
        pid = fork();
        if (!pid)
                return run_tests(runtime);

        while (pid != waitpid(pid, &status, WNOHANG))
                for (i = 0; i < count; i++)
                        if (change_clocksource(clocksource_list[i])) {
                                status = -1;
                                goto out;
                        }
out:
        change_clocksource(orig_clk);

        /* Print at the end to not mix output with child process */
        ksft_print_header();
        ksft_set_plan(1);
        ksft_test_result(!status, "clocksource-switch\n");
        ksft_exit(!status);
}