/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1988, 1993, 1994
 *      The Regents of the University of California.  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.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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 <capsicum_helpers.h>
#include <err.h>
#include <errno.h>
#include <limits.h>
#include <math.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <unistd.h>

static volatile sig_atomic_t report_requested;

static void
report_request(int signo __unused)
{
        report_requested = 1;
}

static void __dead2
usage(void)
{
        fprintf(stderr, "usage: sleep number[unit] [...]\n"
            "Unit can be 's' (seconds, the default), "
            "m (minutes), h (hours), or d (days).\n");
        exit(1);
}

static double
parse_interval(const char *arg)
{
        double num;
        char unit, extra;

        switch (sscanf(arg, "%lf%c%c", &num, &unit, &extra)) {
        case 2:
                switch (unit) {
                case 'd':
                        num *= 24;
                        /* FALLTHROUGH */
                case 'h':
                        num *= 60;
                        /* FALLTHROUGH */
                case 'm':
                        num *= 60;
                        /* FALLTHROUGH */
                case 's':
                        if (!isnan(num))
                                return (num);
                }
                break;
        case 1:
                if (!isnan(num))
                        return (num);
        }
        warnx("invalid time interval: %s", arg);
        return (INFINITY);
}

int
main(int argc, char *argv[])
{
        struct timespec time_to_sleep;
        double seconds;
        time_t original;

        if (caph_limit_stdio() < 0 || caph_enter() < 0)
                err(1, "capsicum");

        while (getopt(argc, argv, "") != -1)
                usage();
        argc -= optind;
        argv += optind;
        if (argc < 1)
                usage();

        seconds = 0;
        while (argc--)
                seconds += parse_interval(*argv++);
        if (seconds > INT_MAX)
                usage();
        if (seconds < 1e-9)
                exit(0);
        original = time_to_sleep.tv_sec = (time_t)seconds;
        time_to_sleep.tv_nsec = 1e9 * (seconds - time_to_sleep.tv_sec);

        signal(SIGINFO, report_request);

        while (nanosleep(&time_to_sleep, &time_to_sleep) != 0) {
                if (errno != EINTR)
                        err(1, "nanosleep");
                if (report_requested) {
                        /* Reporting does not bother with nanoseconds. */
                        warnx("about %ld second(s) left out of the original %ld",
                            (long)time_to_sleep.tv_sec, (long)original);
                        report_requested = 0;
                }
        }

        exit(0);
}