/*-
 * Copyright (c) 2015 Jilles Tjoelker
 * 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.
 */

#include <sys/cdefs.h>
#include <sys/stat.h>

#include <errno.h>
#include <fcntl.h>
#include <time.h>

#ifndef UTIME_NOW
#define UTIME_NOW       -1
#define UTIME_OMIT      -2
#endif

int
futimens(int fd, const struct timespec times[2])
{
        struct timeval now, tv[2], *tvp;
        struct stat sb;
        int osreldate;

        if (times == NULL || (times[0].tv_nsec == UTIME_NOW &&
            times[1].tv_nsec == UTIME_NOW))
                tvp = NULL;
        else if (times[0].tv_nsec == UTIME_OMIT &&
            times[1].tv_nsec == UTIME_OMIT)
                return (0);
        else {
                if ((times[0].tv_nsec < 0 || times[0].tv_nsec > 999999999) &&
                    times[0].tv_nsec != UTIME_NOW &&
                    times[0].tv_nsec != UTIME_OMIT) {
                        errno = EINVAL;
                        return (-1);
                }
                if ((times[1].tv_nsec < 0 || times[1].tv_nsec > 999999999) &&
                    times[1].tv_nsec != UTIME_NOW &&
                    times[1].tv_nsec != UTIME_OMIT) {
                        errno = EINVAL;
                        return (-1);
                }
                tv[0].tv_sec = times[0].tv_sec;
                tv[0].tv_usec = times[0].tv_nsec / 1000;
                tv[1].tv_sec = times[1].tv_sec;
                tv[1].tv_usec = times[1].tv_nsec / 1000;
                tvp = tv;
                if (times[0].tv_nsec == UTIME_OMIT ||
                    times[1].tv_nsec == UTIME_OMIT) {
                        if (fstat(fd, &sb) == -1)
                                return (-1);
                        if (times[0].tv_nsec == UTIME_OMIT) {
                                tv[0].tv_sec = sb.st_atim.tv_sec;
                                tv[0].tv_usec = sb.st_atim.tv_nsec / 1000;
                        }
                        if (times[1].tv_nsec == UTIME_OMIT) {
                                tv[1].tv_sec = sb.st_mtim.tv_sec;
                                tv[1].tv_usec = sb.st_mtim.tv_nsec / 1000;
                        }
                }
                if (times[0].tv_nsec == UTIME_NOW ||
                    times[1].tv_nsec == UTIME_NOW) {
                        if (gettimeofday(&now, NULL) == -1)
                                return (-1);
                        if (times[0].tv_nsec == UTIME_NOW)
                                tv[0] = now;
                        if (times[1].tv_nsec == UTIME_NOW)
                                tv[1] = now;
                }
        }
        return (futimes(fd, tvp));
}