/*      $NetBSD: dm.c,v 1.30 2021/05/02 12:50:44 rillig Exp $   */

/*
 * Copyright (c) 1987, 1993
 *      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) 1987, 1993\
 The Regents of the University of California.  All rights reserved.");
#endif /* not lint */

#ifndef lint
#if 0
static char sccsid[] = "@(#)dm.c        8.1 (Berkeley) 5/31/93";
#else
__RCSID("$NetBSD: dm.c,v 1.30 2021/05/02 12:50:44 rillig Exp $");
#endif
#endif /* not lint */

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

#include <err.h>
#include <ctype.h>
#include <errno.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>

#include "utmpentry.h"
#include "pathnames.h"

static time_t   now;                    /* current time value */
static int      priority = 0;           /* priority game runs at */
static char     *game,                  /* requested game */
                *gametty;               /* from tty? */

static void c_day(const char *, const char *, const char *);
static void c_game(const char *, const char  *, const char *, const char *);
static void c_tty(const char *);
static const char *hour(int);
static double load(void);
static void nogamefile(void);
static void play(char **) __dead;
static void read_config(void);
static int users(void);

#ifdef LOG
static void logfile(void);
#endif

int
main(int argc __unused, char *argv[])
{
        char *cp;

        nogamefile();
        game = (cp = strrchr(*argv, '/')) ? ++cp : *argv;

        if (!strcmp(game, "dm"))
                exit(0);

        gametty = ttyname(0);
        unsetenv("TZ");
        (void)time(&now);
        read_config();
#ifdef LOG
        logfile();
#endif
        play(argv);
        /*NOTREACHED*/
        return (0);
}

/*
 * play --
 *      play the game
 */
static void
play(char **args)
{
        char pbuf[MAXPATHLEN];

        snprintf(pbuf, sizeof(pbuf), "%s%s", _PATH_HIDE, game);
        if (priority > 0)       /* < 0 requires root */
                (void)setpriority(PRIO_PROCESS, 0, priority);
        execv(pbuf, args);
        err(1, "%s", pbuf);
}

/*
 * read_config --
 *      read through config file, looking for key words.
 */
static void
read_config(void)
{
        FILE *cfp;
        char lbuf[BUFSIZ], f1[40], f2[40], f3[40], f4[40], f5[40];

        if (!(cfp = fopen(_PATH_CONFIG, "r")))
                return;
        while (fgets(lbuf, sizeof(lbuf), cfp))
                switch (*lbuf) {
                case 'b':               /* badtty */
                        if (sscanf(lbuf, "%39s%39s", f1, f2) != 2 ||
                            strcasecmp(f1, "badtty"))
                                break;
                        c_tty(f2);
                        break;
                case 'g':               /* game */
                        if (sscanf(lbuf, "%39s%39s%39s%39s%39s",
                            f1, f2, f3, f4, f5) != 5 || strcasecmp(f1, "game"))
                                break;
                        c_game(f2, f3, f4, f5);
                        break;
                case 't':               /* time */
                        if (sscanf(lbuf, "%39s%39s%39s%39s", f1, f2, f3, f4) != 4 ||
                            strcasecmp(f1, "time"))
                                break;
                        c_day(f2, f3, f4);
                }
        (void)fclose(cfp);
}

/*
 * c_day --
 *      if day is today, see if okay to play
 */
static void
c_day(const char *s_day, const char *s_start, const char *s_stop)
{
        static const char *const days[] = {
                "sunday", "monday", "tuesday", "wednesday",
                "thursday", "friday", "saturday",
        };
        static struct tm *ct;
        int start, stop;

        if (!ct)
                ct = localtime(&now);
        if (strcasecmp(s_day, days[ct->tm_wday]))
                return;
        if (!isdigit((unsigned char)*s_start) ||
            !isdigit((unsigned char)*s_stop))
                return;
        start = atoi(s_start);
        stop = atoi(s_stop);
        if (ct->tm_hour >= start && ct->tm_hour < stop) {
                if (start == 0 && stop == 24)
                        errx(0, "Sorry, games are not available today.");
                else
                        errx(0, "Sorry, games are not available from %s to %s today.",
                             hour(start), hour(stop));
        }
}

/*
 * c_tty --
 *      decide if this tty can be used for games.
 */
static void
c_tty(const char *tty)
{
        static int first = 1;
        static char *p_tty;

        if (first) {
                p_tty = strrchr(gametty, '/');
                first = 0;
        }

        if (!strcmp(gametty, tty) || (p_tty && !strcmp(p_tty, tty)))
                errx(1, "Sorry, you may not play games on %s.", gametty);
}

/*
 * c_game --
 *      see if game can be played now.
 */
static void
c_game(const char *s_game, const char *s_load, const char *s_users,
       const char *s_priority)
{
        static int found;

        if (found)
                return;
        if (strcmp(game, s_game) && strcasecmp("default", s_game))
                return;
        ++found;
        if (isdigit((unsigned char)*s_load) && atoi(s_load) < load())
                errx(0, "Sorry, the load average is too high right now.");
        if (isdigit((unsigned char)*s_users) && atoi(s_users) <= users())
                errx(0, "Sorry, there are too many users logged on right now.");
        if (isdigit((unsigned char)*s_priority))
                priority = atoi(s_priority);
}

/*
 * load --
 *      return 15 minute load average
 */
static double
load(void)
{
        double avenrun[3];

        if (getloadavg(avenrun, sizeof(avenrun)/sizeof(avenrun[0])) < 0)
                err(1, "getloadavg() failed");
        return (avenrun[2]);
}

/*
 * users --
 *      return current number of users
 *      todo: check idle time; if idle more than X minutes, don't
 *      count them.
 */
static int
users(void)
{
        struct utmpentry *ep;
        int nusers;

        nusers = getutentries(NULL, &ep);
        return nusers;
}

static void
nogamefile(void)
{
        int fd, n;
        char buf[BUFSIZ];

        if ((fd = open(_PATH_NOGAMES, O_RDONLY, 0)) >= 0) {
#define MESG    "Sorry, no games right now.\n\n"
                (void)write(2, MESG, sizeof(MESG) - 1);
                while ((n = read(fd, buf, sizeof(buf))) > 0)
                        (void)write(2, buf, n);
                exit(1);
        }
}

/*
 * hour --
 *      print out the hour in human form
 */
static const char *
hour(int h)
{
        static const char *const hours[] = {
            "midnight", "1am", "2am", "3am", "4am", "5am",
            "6am", "7am", "8am", "9am", "10am", "11am",
            "noon", "1pm", "2pm", "3pm", "4pm", "5pm",
            "6pm", "7pm", "8pm", "9pm", "10pm", "11pm", "midnight" };

        if (h < 0 || h > 24)
                return ("BAD TIME");
        else
                return (hours[h]);
}

#ifdef LOG
/*
 * logfile --
 *      log play of game
 */
static void
logfile(void)
{
        struct passwd *pw;
        FILE *lp;
        uid_t uid;
        int lock_cnt;

        if (lp = fopen(_PATH_LOG, "a")) {
                for (lock_cnt = 0;; ++lock_cnt) {
                        if (!flock(fileno(lp), LOCK_EX))
                                break;
                        if (lock_cnt == 4) {
                                warnx("log lock");
                                (void)fclose(lp);
                                return;
                        }
                        sleep(1);
                }
                if (pw = getpwuid(uid = getuid()))
                        fputs(pw->pw_name, lp);
                else
                        fprintf(lp, "%u", uid);
                fprintf(lp, "\t%s\t%s\t%s", game, gametty, ctime(&now));
                (void)flock(fileno(lp), LOCK_UN);
                (void)fclose(lp);
        }
}
#endif /* LOG */