usr/src/games/dm/dm.c

/*
 * Copyright (c) 1987 Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that: (1) source distributions retain this entire copyright
 * notice and comment, and (2) distributions including binaries display
 * the following acknowledgement:  ``This product includes software
 * developed by the University of California, Berkeley and its contributors''
 * in the documentation or other materials provided with the distribution
 * and in all advertising materials mentioning features or use of this
 * software. 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 ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

#ifndef lint
char copyright[] =
"@(#) Copyright (c) 1987 Regents of the University of California.\n\
 All rights reserved.\n";
#endif /* not lint */

#ifndef lint
static char sccsid[] = "@(#)dm.c        5.15 (Berkeley) 6/1/90";
#endif /* not lint */

#include <sys/param.h>
#include <sys/file.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <pwd.h>
#include <utmp.h>
#include <nlist.h>
#include <stdio.h>
#include <ctype.h>
#include "pathnames.h"

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

/*ARGSUSED*/
main(argc, argv)
        int argc;
        char **argv;
{
        char *cp, *rindex(), *ttyname();
        time_t time();

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

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

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

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

        (void)strcpy(pbuf, _PATH_HIDE);
        (void)strcpy(pbuf + sizeof(_PATH_HIDE) - 1, game);
        if (priority > 0)       /* < 0 requires root */
                (void)setpriority(PRIO_PROCESS, 0, priority);
        setgid(getgid());       /* we run setgid kmem; lose it */
        execv(pbuf, args);
        (void)fprintf(stderr, "dm: %s: %s\n", pbuf, strerror(errno));
        exit(1);
}

/*
 * read_config --
 *      read through config file, looking for key words.
 */
static
read_config()
{
        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, "%s%s", f1, f2) != 2 ||
                            strcasecmp(f1, "badtty"))
                                break;
                        c_tty(f2);
                        break;
                case 'g':               /* game */
                        if (sscanf(lbuf, "%s%s%s%s%s",
                            f1, f2, f3, f4, f5) != 5 || strcasecmp(f1, "game"))
                                break;
                        c_game(f2, f3, f4, f5);
                        break;
                case 't':               /* time */
                        if (sscanf(lbuf, "%s%s%s%s", 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
c_day(s_day, s_start, s_stop)
        char *s_day, *s_start, *s_stop;
{
        static char *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(*s_start) || !isdigit(*s_stop))
                return;
        start = atoi(s_start);
        stop = atoi(s_stop);
        if (ct->tm_hour >= start && ct->tm_hour < stop) {
                fputs("dm: Sorry, games are not available from ", stderr);
                hour(start);
                fputs(" to ", stderr);
                hour(stop);
                fputs(" today.\n", stderr);
                exit(0);
        }
}

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

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

        if (!strcmp(gametty, tty) || p_tty && !strcmp(p_tty, tty)) {
                fprintf(stderr, "dm: Sorry, you may not play games on %s.\n", gametty);
                exit(0);
        }
}

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

        if (found)
                return;
        if (strcmp(game, s_game) && strcasecmp("default", s_game))
                return;
        ++found;
        if (isdigit(*s_load) && atoi(s_load) < load()) {
                fputs("dm: Sorry, the load average is too high right now.\n", stderr);
                exit(0);
        }
        if (isdigit(*s_users) && atoi(s_users) <= users()) {
                fputs("dm: Sorry, there are too many users logged on right now.\n", stderr);
                exit(0);
        }
        if (isdigit(*s_priority))
                priority = atoi(s_priority);
}

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

        if (getloadavg(avenrun, sizeof(avenrun)/sizeof(avenrun[0])) < 0) {
                fputs("dm: getloadavg() failed.\n", stderr);
                exit(1);
        }
        return(avenrun[2]);
}

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

        register int nusers, utmp;
        struct utmp buf;

        if ((utmp = open(_PATH_UTMP, O_RDONLY, 0)) < 0) {
                (void)fprintf(stderr, "dm: %s: %s\n",
                    _PATH_UTMP, strerror(errno));
                exit(1);
        }
        for (nusers = 0; read(utmp, (char *)&buf, sizeof(struct utmp)) > 0;)
                if (buf.ut_name[0] != '\0')
                        ++nusers;
        return(nusers);
}

static
nogamefile()
{
        register 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
hour(h)
        int h;
{
        switch(h) {
        case 0:
                fputs("midnight", stderr);
                break;
        case 12:
                fputs("noon", stderr);
                break;
        default:
                if (h > 12)
                        fprintf(stderr, "%dpm", h - 12);
                else
                        fprintf(stderr, "%dam", h);
        }
}

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

        if (lp = fopen(_PATH_LOG, "a")) {
                for (lock_cnt = 0;; ++lock_cnt) {
                        if (!flock(fileno(lp), LOCK_EX))
                                break;
                        if (lock_cnt == 4) {
                                perror("dm: log lock");
                                (void)fclose(lp);
                                return;
                        }
                        sleep((u_int)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)fclose(lp);
                (void)flock(fileno(lp), LOCK_UN);
        }
}
#endif /* LOG */