/* $NetBSD: sleep.c,v 1.30 2019/03/10 15:18:45 kre Exp $ */

/*
 * 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 <sys/cdefs.h>
#ifndef lint
__COPYRIGHT("@(#) Copyright (c) 1988, 1993, 1994\
 The Regents of the University of California.  All rights reserved.");
#endif /* not lint */

#ifndef lint
#if 0
static char sccsid[] = "@(#)sleep.c     8.3 (Berkeley) 4/2/94";
#else
__RCSID("$NetBSD: sleep.c,v 1.30 2019/03/10 15:18:45 kre Exp $");
#endif
#endif /* not lint */

#include <ctype.h>
#include <err.h>
#include <errno.h>
#include <locale.h>
#include <math.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>

__dead static void alarmhandle(int);
__dead static void usage(void);

static void report(const time_t, const time_t, const char *const);

static volatile sig_atomic_t report_requested;
static void
report_request(int signo __unused)
{

        report_requested = 1;
}

int
main(int argc, char *argv[])
{
        char *arg, *temp;
        const char *msg;
        double fval, ival, val;
        struct timespec ntime;
        struct timespec endtime;
        struct timespec now;
        time_t original;
        int ch, fracflag;

        setprogname(argv[0]);
        (void)setlocale(LC_ALL, "");

        (void)signal(SIGALRM, alarmhandle);

        while ((ch = getopt(argc, argv, "")) != -1)
                switch(ch) {
                default:
                        usage();
                }
        argc -= optind;
        argv += optind;

        if (argc != 1)
                usage();

        /*
         * Okay, why not just use atof for everything? Why bother
         * checking if there is a fraction in use? Because the old
         * sleep handled the full range of integers, that's why, and a
         * double can't handle a large long. This is fairly useless
         * given how large a number a double can hold on most
         * machines, but now we won't ever have trouble. If you want
         * 1000000000.9 seconds of sleep, well, that's your
         * problem. Why use an isdigit() check instead of checking for
         * a period? Because doing it this way means locales will be
         * handled transparently by the atof code.
         *
         * Since fracflag is set for any non-digit, we also fall
         * into the floating point conversion path if the input
         * is hex (the 'x' in 0xA is not a digit).  Then if
         * strtod() handles hex (on NetBSD it does) so will we.
         * That path is also taken for scientific notation (1.2e+3)
         * and when the input is simply nonsense.
         */
        fracflag = 0;
        arg = *argv;
        for (temp = arg; *temp != '\0'; temp++)
                if (!isdigit((unsigned char)*temp)) {
                        ch = *temp;
                        fracflag++;
                }

        if (fracflag) {
                /*
                 * If we cannot convert the value using the user's locale
                 * then try again using the C locale, so strtod() can always
                 * parse values like 2.5, even if the user's locale uses
                 * a different decimal radix character (like ',')
                 *
                 * (but only if that is the potential problem)
                 */
                val = strtod(arg, &temp);
                if (*temp != '\0')
                        val = strtod_l(arg, &temp, LC_C_LOCALE);
                if (val < 0 || temp == arg || *temp != '\0')
                        usage();

                ival = floor(val);
                fval = (1000000000 * (val-ival));
                ntime.tv_sec = ival;
                if ((double)ntime.tv_sec != ival)
                        errx(1, "requested delay (%s) out of range", arg);
                ntime.tv_nsec = fval;

                if (ntime.tv_sec == 0 && ntime.tv_nsec == 0)
                        return EXIT_SUCCESS;    /* was 0.0 or underflowed */
        } else {
                errno = 0;
                ntime.tv_sec = strtol(arg, &temp, 10);
                if (ntime.tv_sec < 0 || temp == arg || *temp != '\0')
                        usage();
                if (errno == ERANGE)
                        errx(EXIT_FAILURE, "Requested delay (%s) out of range",
                            arg);
                else if (errno != 0)
                        err(EXIT_FAILURE, "Requested delay (%s)", arg);

                if (ntime.tv_sec == 0)
                        return EXIT_SUCCESS;
                ntime.tv_nsec = 0;
        }

        original = ntime.tv_sec;
        if (original < 86400) {
                if (ntime.tv_nsec > 1000000000 * 2 / 3) {
                        original++;
                        msg = " less a bit";
                } else if (ntime.tv_nsec != 0)
                        msg = " and a bit";
                else
                        msg = "";
        } else
                msg = "";

        if (clock_gettime(CLOCK_MONOTONIC, &now) != 0)
                err(EXIT_FAILURE, "clock_gettime");
        timespecadd(&now, &ntime, &endtime);

        if (endtime.tv_sec < now.tv_sec || (endtime.tv_sec == now.tv_sec &&
            endtime.tv_nsec <= now.tv_nsec))
                errx(EXIT_FAILURE, "cannot sleep beyond the end of time");

        signal(SIGINFO, report_request);
        for (;;) {
                int e;

                if ((e = clock_nanosleep(CLOCK_MONOTONIC, TIMER_ABSTIME,
                     &endtime, NULL)) == 0)
                        return EXIT_SUCCESS;

                if (!report_requested || e != EINTR) {
                        errno = e;
                        err(EXIT_FAILURE, "clock_nanotime");
                }

                report_requested = 0;
                if (clock_gettime(CLOCK_MONOTONIC, &now) != 0) /* Huh? */
                        continue;

                timespecsub(&endtime, &now, &ntime);
                report(ntime.tv_sec, original, msg);
        }
}

        /* Reporting does not bother with nanoseconds. */
static void
report(const time_t remain, const time_t original, const char * const msg)
{
        if (remain == 0)
                warnx("In the final moments of the original"
                    " %g%s second%s", (double)original, msg,
                    original == 1 && *msg == '\0' ? "" : "s");
        else if (remain < 2000)
                warnx("Between %jd and %jd seconds left"
                    " out of the original %g%s",
                    (intmax_t)remain, (intmax_t)remain + 1, (double)original,
                    msg);
        else if ((original - remain) < 100000 && (original-remain) < original/8)
                warnx("Have waited only %jd second%s of the original %g%s",
                        (intmax_t)(original - remain),
                        (original - remain) == 1 ? "" : "s",
                        (double)original, msg);
        else
                warnx("Approximately %g seconds left out of the original %g%s",
                        (double)remain, (double)original, msg);
}

static void
usage(void)
{
        (void)fprintf(stderr, "usage: %s seconds\n", getprogname());
        exit(EXIT_FAILURE);
        /* NOTREACHED */
}

/* ARGSUSED */
static void
alarmhandle(int i)
{
        _exit(EXIT_SUCCESS);
        /* NOTREACHED */
}