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      1 /*	$NetBSD: dm.c,v 1.30 2021/05/02 12:50:44 rillig Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1987, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. Neither the name of the University nor the names of its contributors
     16  *    may be used to endorse or promote products derived from this software
     17  *    without specific prior written permission.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     29  * SUCH DAMAGE.
     30  */
     31 
     32 #include <sys/cdefs.h>
     33 #ifndef lint
     34 __COPYRIGHT("@(#) Copyright (c) 1987, 1993\
     35  The Regents of the University of California.  All rights reserved.");
     36 #endif /* not lint */
     37 
     38 #ifndef lint
     39 #if 0
     40 static char sccsid[] = "@(#)dm.c	8.1 (Berkeley) 5/31/93";
     41 #else
     42 __RCSID("$NetBSD: dm.c,v 1.30 2021/05/02 12:50:44 rillig Exp $");
     43 #endif
     44 #endif /* not lint */
     45 
     46 #include <sys/param.h>
     47 #include <sys/file.h>
     48 #include <sys/time.h>
     49 #include <sys/resource.h>
     50 
     51 #include <err.h>
     52 #include <ctype.h>
     53 #include <errno.h>
     54 #include <pwd.h>
     55 #include <stdio.h>
     56 #include <stdlib.h>
     57 #include <string.h>
     58 #include <time.h>
     59 #include <unistd.h>
     60 
     61 #include "utmpentry.h"
     62 #include "pathnames.h"
     63 
     64 static time_t	now;			/* current time value */
     65 static int	priority = 0;		/* priority game runs at */
     66 static char	*game,			/* requested game */
     67 		*gametty;		/* from tty? */
     68 
     69 static void c_day(const char *, const char *, const char *);
     70 static void c_game(const char *, const char  *, const char *, const char *);
     71 static void c_tty(const char *);
     72 static const char *hour(int);
     73 static double load(void);
     74 static void nogamefile(void);
     75 static void play(char **) __dead;
     76 static void read_config(void);
     77 static int users(void);
     78 
     79 #ifdef LOG
     80 static void logfile(void);
     81 #endif
     82 
     83 int
     84 main(int argc __unused, char *argv[])
     85 {
     86 	char *cp;
     87 
     88 	nogamefile();
     89 	game = (cp = strrchr(*argv, '/')) ? ++cp : *argv;
     90 
     91 	if (!strcmp(game, "dm"))
     92 		exit(0);
     93 
     94 	gametty = ttyname(0);
     95 	unsetenv("TZ");
     96 	(void)time(&now);
     97 	read_config();
     98 #ifdef LOG
     99 	logfile();
    100 #endif
    101 	play(argv);
    102 	/*NOTREACHED*/
    103 	return (0);
    104 }
    105 
    106 /*
    107  * play --
    108  *	play the game
    109  */
    110 static void
    111 play(char **args)
    112 {
    113 	char pbuf[MAXPATHLEN];
    114 
    115 	snprintf(pbuf, sizeof(pbuf), "%s%s", _PATH_HIDE, game);
    116 	if (priority > 0)	/* < 0 requires root */
    117 		(void)setpriority(PRIO_PROCESS, 0, priority);
    118 	execv(pbuf, args);
    119 	err(1, "%s", pbuf);
    120 }
    121 
    122 /*
    123  * read_config --
    124  *	read through config file, looking for key words.
    125  */
    126 static void
    127 read_config(void)
    128 {
    129 	FILE *cfp;
    130 	char lbuf[BUFSIZ], f1[40], f2[40], f3[40], f4[40], f5[40];
    131 
    132 	if (!(cfp = fopen(_PATH_CONFIG, "r")))
    133 		return;
    134 	while (fgets(lbuf, sizeof(lbuf), cfp))
    135 		switch (*lbuf) {
    136 		case 'b':		/* badtty */
    137 			if (sscanf(lbuf, "%39s%39s", f1, f2) != 2 ||
    138 			    strcasecmp(f1, "badtty"))
    139 				break;
    140 			c_tty(f2);
    141 			break;
    142 		case 'g':		/* game */
    143 			if (sscanf(lbuf, "%39s%39s%39s%39s%39s",
    144 			    f1, f2, f3, f4, f5) != 5 || strcasecmp(f1, "game"))
    145 				break;
    146 			c_game(f2, f3, f4, f5);
    147 			break;
    148 		case 't':		/* time */
    149 			if (sscanf(lbuf, "%39s%39s%39s%39s", f1, f2, f3, f4) != 4 ||
    150 			    strcasecmp(f1, "time"))
    151 				break;
    152 			c_day(f2, f3, f4);
    153 		}
    154 	(void)fclose(cfp);
    155 }
    156 
    157 /*
    158  * c_day --
    159  *	if day is today, see if okay to play
    160  */
    161 static void
    162 c_day(const char *s_day, const char *s_start, const char *s_stop)
    163 {
    164 	static const char *const days[] = {
    165 		"sunday", "monday", "tuesday", "wednesday",
    166 		"thursday", "friday", "saturday",
    167 	};
    168 	static struct tm *ct;
    169 	int start, stop;
    170 
    171 	if (!ct)
    172 		ct = localtime(&now);
    173 	if (strcasecmp(s_day, days[ct->tm_wday]))
    174 		return;
    175 	if (!isdigit((unsigned char)*s_start) ||
    176 	    !isdigit((unsigned char)*s_stop))
    177 		return;
    178 	start = atoi(s_start);
    179 	stop = atoi(s_stop);
    180 	if (ct->tm_hour >= start && ct->tm_hour < stop) {
    181 		if (start == 0 && stop == 24)
    182 			errx(0, "Sorry, games are not available today.");
    183 		else
    184 			errx(0, "Sorry, games are not available from %s to %s today.",
    185 			     hour(start), hour(stop));
    186 	}
    187 }
    188 
    189 /*
    190  * c_tty --
    191  *	decide if this tty can be used for games.
    192  */
    193 static void
    194 c_tty(const char *tty)
    195 {
    196 	static int first = 1;
    197 	static char *p_tty;
    198 
    199 	if (first) {
    200 		p_tty = strrchr(gametty, '/');
    201 		first = 0;
    202 	}
    203 
    204 	if (!strcmp(gametty, tty) || (p_tty && !strcmp(p_tty, tty)))
    205 		errx(1, "Sorry, you may not play games on %s.", gametty);
    206 }
    207 
    208 /*
    209  * c_game --
    210  *	see if game can be played now.
    211  */
    212 static void
    213 c_game(const char *s_game, const char *s_load, const char *s_users,
    214        const char *s_priority)
    215 {
    216 	static int found;
    217 
    218 	if (found)
    219 		return;
    220 	if (strcmp(game, s_game) && strcasecmp("default", s_game))
    221 		return;
    222 	++found;
    223 	if (isdigit((unsigned char)*s_load) && atoi(s_load) < load())
    224 		errx(0, "Sorry, the load average is too high right now.");
    225 	if (isdigit((unsigned char)*s_users) && atoi(s_users) <= users())
    226 		errx(0, "Sorry, there are too many users logged on right now.");
    227 	if (isdigit((unsigned char)*s_priority))
    228 		priority = atoi(s_priority);
    229 }
    230 
    231 /*
    232  * load --
    233  *	return 15 minute load average
    234  */
    235 static double
    236 load(void)
    237 {
    238 	double avenrun[3];
    239 
    240 	if (getloadavg(avenrun, sizeof(avenrun)/sizeof(avenrun[0])) < 0)
    241 		err(1, "getloadavg() failed");
    242 	return (avenrun[2]);
    243 }
    244 
    245 /*
    246  * users --
    247  *	return current number of users
    248  *	todo: check idle time; if idle more than X minutes, don't
    249  *	count them.
    250  */
    251 static int
    252 users(void)
    253 {
    254 	struct utmpentry *ep;
    255 	int nusers;
    256 
    257 	nusers = getutentries(NULL, &ep);
    258 	return nusers;
    259 }
    260 
    261 static void
    262 nogamefile(void)
    263 {
    264 	int fd, n;
    265 	char buf[BUFSIZ];
    266 
    267 	if ((fd = open(_PATH_NOGAMES, O_RDONLY, 0)) >= 0) {
    268 #define	MESG	"Sorry, no games right now.\n\n"
    269 		(void)write(2, MESG, sizeof(MESG) - 1);
    270 		while ((n = read(fd, buf, sizeof(buf))) > 0)
    271 			(void)write(2, buf, n);
    272 		exit(1);
    273 	}
    274 }
    275 
    276 /*
    277  * hour --
    278  *	print out the hour in human form
    279  */
    280 static const char *
    281 hour(int h)
    282 {
    283 	static const char *const hours[] = {
    284 	    "midnight", "1am", "2am", "3am", "4am", "5am",
    285 	    "6am", "7am", "8am", "9am", "10am", "11am",
    286 	    "noon", "1pm", "2pm", "3pm", "4pm", "5pm",
    287 	    "6pm", "7pm", "8pm", "9pm", "10pm", "11pm", "midnight" };
    288 
    289 	if (h < 0 || h > 24)
    290 		return ("BAD TIME");
    291 	else
    292 		return (hours[h]);
    293 }
    294 
    295 #ifdef LOG
    296 /*
    297  * logfile --
    298  *	log play of game
    299  */
    300 static void
    301 logfile(void)
    302 {
    303 	struct passwd *pw;
    304 	FILE *lp;
    305 	uid_t uid;
    306 	int lock_cnt;
    307 
    308 	if (lp = fopen(_PATH_LOG, "a")) {
    309 		for (lock_cnt = 0;; ++lock_cnt) {
    310 			if (!flock(fileno(lp), LOCK_EX))
    311 				break;
    312 			if (lock_cnt == 4) {
    313 				warnx("log lock");
    314 				(void)fclose(lp);
    315 				return;
    316 			}
    317 			sleep(1);
    318 		}
    319 		if (pw = getpwuid(uid = getuid()))
    320 			fputs(pw->pw_name, lp);
    321 		else
    322 			fprintf(lp, "%u", uid);
    323 		fprintf(lp, "\t%s\t%s\t%s", game, gametty, ctime(&now));
    324 		(void)flock(fileno(lp), LOCK_UN);
    325 		(void)fclose(lp);
    326 	}
    327 }
    328 #endif /* LOG */
    329