// SPDX-License-Identifier: GPL-2.0
#define _GNU_SOURCE
#include <sys/types.h>
#include <sys/stat.h>
#include <errno.h>
#include <fcntl.h>
#include <sched.h>
#include <time.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/syscall.h>
#include <dlfcn.h>

#include "log.h"
#include "timens.h"

typedef int (*vgettime_t)(clockid_t, struct timespec *);

vgettime_t vdso_clock_gettime;

static void fill_function_pointers(void)
{
        void *vdso = dlopen("linux-vdso.so.1",
                            RTLD_LAZY | RTLD_LOCAL | RTLD_NOLOAD);
        if (!vdso)
                vdso = dlopen("linux-gate.so.1",
                              RTLD_LAZY | RTLD_LOCAL | RTLD_NOLOAD);
        if (!vdso)
                vdso = dlopen("linux-vdso32.so.1",
                              RTLD_LAZY | RTLD_LOCAL | RTLD_NOLOAD);
        if (!vdso)
                vdso = dlopen("linux-vdso64.so.1",
                              RTLD_LAZY | RTLD_LOCAL | RTLD_NOLOAD);
        if (!vdso) {
                pr_err("[WARN]\tfailed to find vDSO\n");
                return;
        }

        vdso_clock_gettime = (vgettime_t)dlsym(vdso, "__vdso_clock_gettime");
        if (!vdso_clock_gettime)
                vdso_clock_gettime = (vgettime_t)dlsym(vdso, "__kernel_clock_gettime");
        if (!vdso_clock_gettime)
                pr_err("Warning: failed to find clock_gettime in vDSO\n");

}

static void test(clock_t clockid, char *clockstr, bool in_ns)
{
        struct timespec tp, start;
        long i = 0;
        const int timeout = 3;

        vdso_clock_gettime(clockid, &start);
        tp = start;
        for (tp = start; start.tv_sec + timeout > tp.tv_sec ||
                         (start.tv_sec + timeout == tp.tv_sec &&
                          start.tv_nsec > tp.tv_nsec); i++) {
                vdso_clock_gettime(clockid, &tp);
        }

        ksft_test_result_pass("%s:\tclock: %10s\tcycles:\t%10ld\n",
                              in_ns ? "ns" : "host", clockstr, i);
}

int main(int argc, char *argv[])
{
        time_t offset = 10;
        int nsfd;

        ksft_print_header();

        ksft_set_plan(8);

        fill_function_pointers();

        test(CLOCK_MONOTONIC, "monotonic", false);
        test(CLOCK_MONOTONIC_COARSE, "monotonic-coarse", false);
        test(CLOCK_MONOTONIC_RAW, "monotonic-raw", false);
        test(CLOCK_BOOTTIME, "boottime", false);

        nscheck();

        if (unshare_timens())
                return 1;

        nsfd = open("/proc/self/ns/time_for_children", O_RDONLY);
        if (nsfd < 0)
                return pr_perror("Can't open a time namespace");

        if (_settime(CLOCK_MONOTONIC, offset))
                return 1;
        if (_settime(CLOCK_BOOTTIME, offset))
                return 1;

        if (setns(nsfd, CLONE_NEWTIME))
                return pr_perror("setns");

        test(CLOCK_MONOTONIC, "monotonic", true);
        test(CLOCK_MONOTONIC_COARSE, "monotonic-coarse", true);
        test(CLOCK_MONOTONIC_RAW, "monotonic-raw", true);
        test(CLOCK_BOOTTIME, "boottime", true);

        ksft_exit_pass();
        return 0;
}