/* 
 * dhcpcd - DHCP client daemon
 * Copyright (c) 2006-2009 Roy Marples <roy@marples.name>
 * All rights reserved

 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/* Needed define to get at getline for glibc and FreeBSD */
#ifndef _GNU_SOURCE
#  define _GNU_SOURCE
#endif

#include <sys/cdefs.h>

#ifdef __APPLE__
#  include <mach/mach_time.h>
#  include <mach/kern_return.h>
#endif

#include <sys/param.h>
#include <sys/time.h>

#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#ifdef BSD
#  include <paths.h>
#endif
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>

#include "common.h"

#ifndef _PATH_DEVNULL
#  define _PATH_DEVNULL "/dev/null"
#endif

int clock_monotonic;
#ifdef DEBUG_MEMORY
static char lbuf_set;
#endif

#ifdef DEBUG_MEMORY
static void
free_lbuf(void)
{
        free(lbuf);
        lbuf = NULL;
}
#endif

/* Handy function to get the time.
 * We only care about time advancements, not the actual time itself
 * Which is why we use CLOCK_MONOTONIC, but it is not available on all
 * platforms.
 */
#define NO_MONOTONIC "host does not support a monotonic clock - timing can skew"
int
get_monotonic(struct timeval *tp)
{
        static int posix_clock_set = 0;
#if defined(_POSIX_MONOTONIC_CLOCK) && defined(CLOCK_MONOTONIC)
        struct timespec ts;
        static clockid_t posix_clock;

        if (!posix_clock_set) {
                if (clock_gettime(CLOCK_MONOTONIC, &ts) == 0) {
                        posix_clock = CLOCK_MONOTONIC;
                        clock_monotonic = posix_clock_set = 1;
                }
        }

        if (clock_monotonic) {
                if (clock_gettime(posix_clock, &ts) == 0) {
                        tp->tv_sec = ts.tv_sec;
                        tp->tv_usec = ts.tv_nsec / 1000;
                        return 0;
                }
        }
#elif defined(__APPLE__)
#define NSEC_PER_SEC 1000000000
        /* We can use mach kernel functions here.
         * This is crap though - why can't they implement clock_gettime?*/
        static struct mach_timebase_info info = { 0, 0 };
        static double factor = 0.0;
        uint64_t nano;
        long rem;

        if (!posix_clock_set) {
                if (mach_timebase_info(&info) == KERN_SUCCESS) {
                        factor = (double)info.numer / (double)info.denom;
                        clock_monotonic = posix_clock_set = 1;
                }
        }
        if (clock_monotonic) {
                nano = mach_absolute_time();
                if ((info.denom != 1 || info.numer != 1) && factor != 0.0)
                        nano *= factor;
                tp->tv_sec = nano / NSEC_PER_SEC;
                rem = nano % NSEC_PER_SEC;
                if (rem < 0) {
                        tp->tv_sec--;
                        rem += NSEC_PER_SEC;
                }
                tp->tv_usec = rem / 1000;
                return 0;
        }
#endif

        /* Something above failed, so fall back to gettimeofday */
        if (!posix_clock_set) {
                posix_clock_set = 1;
        }
        return gettimeofday(tp, NULL);
}

time_t
uptime(void)
{
        struct timeval tv;

        if (get_monotonic(&tv) == -1)
                return -1;
        return tv.tv_sec;
}

void *
xmalloc(size_t s)
{
        void *value = malloc(s);

        if (value != NULL)
                return value;
        abort();
        /* NOTREACHED */
}

void *
xzalloc(size_t s)
{
        void *value = xmalloc(s);

        memset(value, 0, s);
        return value;
}

void *
xrealloc(void *ptr, size_t s)
{
        void *value = realloc(ptr, s);

        if (value != NULL)
                return value;
        abort();
        /* NOTREACHED */
}

char *
xstrdup(const char *str)
{
        char *value;

        if (str == NULL)
                return NULL;

        if ((value = strdup(str)) != NULL)
                return value;

        abort();
        /* NOTREACHED */
}