/* vim:ts=4:sts=4:sw=4:et:cindent

 * datefudge.c: Twist system date back N seconds

 *

 * Copyright (C) 2001-2003, Matthias Urlichs <smurf@noris.de>

 * Copyright (C) 2008-2011, Robert Luberda <robert@debian.org>

 *

 */

#define _GNU_SOURCE

#include <sys/file.h>

#include <sys/stat.h>

#include <fcntl.h>

#include <stdio.h>

#include <stdlib.h>

#include <dlfcn.h>

#include <assert.h>

#include <features.h>

#include <stdbool.h>

#include <unistd.h>

#include <time.h>

#include <sys/time.h>

static time_t fudge = 0;

static bool dostatic = false;

static bool fudge_set = false;

static void init_fudge (void)

{

    const char * const fud = getenv("DATEFUDGE");

    if(fud == NULL) return;

    if (sizeof(time_t) <= sizeof(int))

        fudge = atoi(fud);

    else

        fudge = atoll(fud);

    dostatic = getenv("DATEFUDGE_DOSTATIC") != NULL;

    fudge_set = true;

}

static void set_fudge(time_t *seconds)

{

    if (!seconds)

        return;

    if (!fudge_set)

        init_fudge();

    if (dostatic)

        *seconds = fudge;

    else

        *seconds -= fudge;

}

#ifndef __GNU__

time_t time(time_t *x) {

    static time_t (*libc_time)(time_t *) = NULL;

    time_t res;

    if(!libc_time)

        libc_time = (typeof(libc_time))dlsym (RTLD_NEXT, __func__);

    res = (*libc_time)(x);

    set_fudge(x);

    set_fudge(&res;;

    return res;

}

#endif

int __gettimeofday(struct timeval *x, struct timezone *y) {

    static int (*libc_gettimeofday)(struct timeval *, struct timezone *) = NULL;

    int res;

    if(!libc_gettimeofday)

        libc_gettimeofday = (typeof(libc_gettimeofday))dlsym (RTLD_NEXT, __func__);

    res = (*libc_gettimeofday)(x,y);

    if(res) return res;

    set_fudge(&x->tv_sec);

    return 0;

}

int gettimeofday(struct timeval *x, struct timezone *y) {

    return __gettimeofday(x,y);

}

#ifndef __GNU__

int clock_gettime(clockid_t x, struct timespec *y) {

    static int (*libc_clock_gettime)(clockid_t, struct timespec*);

    int res;

    if (!libc_clock_gettime)

        libc_clock_gettime =  (typeof(libc_clock_gettime))dlsym (RTLD_NEXT, __func__);

    res = (*libc_clock_gettime)(x,y);

    if (res || CLOCK_REALTIME != x) return res;

    set_fudge(&y->tv_sec);

    return 0;

}

#endif