dm/dm.c

   1 /*
   2  * Copyright (c) 1987 Regents of the University of California.
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #ifndef lint
  35 char copyright[] =
  36 "@(#) Copyright (c) 1987 Regents of the University of California.\n\
  37  All rights reserved.\n";
  38 #endif /* not lint */
  39
  40 #ifndef lint
  41 /*static char sccsid[] = "from: @(#)dm.c        5.16 (Berkeley) 2/28/91";*/
  42 static char rcsid[] = "$Id: dm.c,v 1.3 1993/08/01 18:55:03 mycroft Exp $";
  43 #endif /* not lint */
  44
  45 #include <sys/param.h>
  46 #include <sys/file.h>
  47 #include <sys/time.h>
  48 #include <sys/resource.h>
  49 #include <pwd.h>
  50 #include <utmp.h>
  51 #include <nlist.h>
  52 #include <stdio.h>
  53 #include <ctype.h>
  54 #include <string.h>
  55 #include "pathnames.h"
  56
  57 extern int errno;
  58 static time_t   now;                    /* current time value */
  59 static int      priority = 0;           /* priority game runs at */
  60 static char     *game,                  /* requested game */
  61                 *gametty;               /* from tty? */
  62
  63 /*ARGSUSED*/
  64 main(argc, argv)
  65         int argc;
  66         char **argv;
  67 {
  68         char *cp, *rindex(), *ttyname();
  69         time_t time();
  70
  71         nogamefile();
  72         game = (cp = rindex(*argv, '/')) ? ++cp : *argv;
  73
  74         if (!strcmp(game, "dm"))
  75                 exit(0);
  76
  77         gametty = ttyname(0);
  78         (void)time(&now);
  79         read_config();
  80 #ifdef LOG
  81         logfile();
  82 #endif
  83         play(argv);
  84         /*NOTREACHED*/
  85 }
  86
  87 /*
  88  * play --
  89  *      play the game
  90  */
  91 play(args)
  92         char **args;
  93 {
  94         char pbuf[MAXPATHLEN];
  95
  96         (void)strcpy(pbuf, _PATH_HIDE);
  97         (void)strcpy(pbuf + sizeof(_PATH_HIDE) - 1, game);
  98         if (priority > 0)       /* < 0 requires root */
  99                 (void)setpriority(PRIO_PROCESS, 0, priority);
 100         setgid(getgid());       /* we run setgid kmem; lose it */
 101         execv(pbuf, args);
 102         (void)fprintf(stderr, "dm: %s: %s\n", pbuf, strerror(errno));
 103         exit(1);
 104 }
 105
 106 /*
 107  * read_config --
 108  *      read through config file, looking for key words.
 109  */
 110 read_config()
 111 {
 112         FILE *cfp;
 113         char lbuf[BUFSIZ], f1[40], f2[40], f3[40], f4[40], f5[40];
 114
 115         if (!(cfp = fopen(_PATH_CONFIG, "r")))
 116                 return;
 117         while (fgets(lbuf, sizeof(lbuf), cfp))
 118                 switch(*lbuf) {
 119                 case 'b':               /* badtty */
 120                         if (sscanf(lbuf, "%s%s", f1, f2) != 2 ||
 121                             strcasecmp(f1, "badtty"))
 122                                 break;
 123                         c_tty(f2);
 124                         break;
 125                 case 'g':               /* game */
 126                         if (sscanf(lbuf, "%s%s%s%s%s",
 127                             f1, f2, f3, f4, f5) != 5 || strcasecmp(f1, "game"))
 128                                 break;
 129                         c_game(f2, f3, f4, f5);
 130                         break;
 131                 case 't':               /* time */
 132                         if (sscanf(lbuf, "%s%s%s%s", f1, f2, f3, f4) != 4 ||
 133                             strcasecmp(f1, "time"))
 134                                 break;
 135                         c_day(f2, f3, f4);
 136                 }
 137         (void)fclose(cfp);
 138 }
 139
 140 /*
 141  * c_day --
 142  *      if day is today, see if okay to play
 143  */
 144 c_day(s_day, s_start, s_stop)
 145         char *s_day, *s_start, *s_stop;
 146 {
 147         static char *days[] = {
 148                 "sunday", "monday", "tuesday", "wednesday",
 149                 "thursday", "friday", "saturday",
 150         };
 151         static struct tm *ct;
 152         int start, stop;
 153
 154         if (!ct)
 155                 ct = localtime(&now);
 156         if (strcasecmp(s_day, days[ct->tm_wday]))
 157                 return;
 158         if (!isdigit(*s_start) || !isdigit(*s_stop))
 159                 return;
 160         start = atoi(s_start);
 161         stop = atoi(s_stop);
 162         if (ct->tm_hour >= start && ct->tm_hour < stop) {
 163                 fputs("dm: Sorry, games are not available from ", stderr);
 164                 hour(start);
 165                 fputs(" to ", stderr);
 166                 hour(stop);
 167                 fputs(" today.\n", stderr);
 168                 exit(0);
 169         }
 170 }
 171
 172 /*
 173  * c_tty --
 174  *      decide if this tty can be used for games.
 175  */
 176 c_tty(tty)
 177         char *tty;
 178 {
 179         static int first = 1;
 180         static char *p_tty;
 181         char *rindex();
 182
 183         if (first) {
 184                 p_tty = rindex(gametty, '/');
 185                 first = 0;
 186         }
 187
 188         if (!strcmp(gametty, tty) || p_tty && !strcmp(p_tty, tty)) {
 189                 fprintf(stderr, "dm: Sorry, you may not play games on %s.\n", gametty);
 190                 exit(0);
 191         }
 192 }
 193
 194 /*
 195  * c_game --
 196  *      see if game can be played now.
 197  */
 198 c_game(s_game, s_load, s_users, s_priority)
 199         char *s_game, *s_load, *s_users, *s_priority;
 200 {
 201         static int found;
 202         double load();
 203
 204         if (found)
 205                 return;
 206         if (strcmp(game, s_game) && strcasecmp("default", s_game))
 207                 return;
 208         ++found;
 209         if (isdigit(*s_load) && atoi(s_load) < load()) {
 210                 fputs("dm: Sorry, the load average is too high right now.\n", stderr);
 211                 exit(0);
 212         }
 213         if (isdigit(*s_users) && atoi(s_users) <= users()) {
 214                 fputs("dm: Sorry, there are too many users logged on right now.\n", stderr);
 215                 exit(0);
 216         }
 217         if (isdigit(*s_priority))
 218                 priority = atoi(s_priority);
 219 }
 220
 221 /*
 222  * load --
 223  *      return 15 minute load average
 224  */
 225 double
 226 load()
 227 {
 228         double avenrun[3];
 229
 230         if (getloadavg(avenrun, sizeof(avenrun)/sizeof(avenrun[0])) < 0) {
 231                 fputs("dm: getloadavg() failed.\n", stderr);
 232                 exit(1);
 233         }
 234         return(avenrun[2]);
 235 }
 236
 237 /*
 238  * users --
 239  *      return current number of users
 240  *      todo: check idle time; if idle more than X minutes, don't
 241  *      count them.
 242  */
 243 users()
 244 {
 245
 246         register int nusers, utmp;
 247         struct utmp buf;
 248
 249         if ((utmp = open(_PATH_UTMP, O_RDONLY, 0)) < 0) {
 250                 (void)fprintf(stderr, "dm: %s: %s\n",
 251                     _PATH_UTMP, strerror(errno));
 252                 exit(1);
 253         }
 254         for (nusers = 0; read(utmp, (char *)&buf, sizeof(struct utmp)) > 0;)
 255                 if (buf.ut_name[0] != '\0')
 256                         ++nusers;
 257         return(nusers);
 258 }
 259
 260 nogamefile()
 261 {
 262         register int fd, n;
 263         char buf[BUFSIZ];
 264
 265         if ((fd = open(_PATH_NOGAMES, O_RDONLY, 0)) >= 0) {
 266 #define MESG    "Sorry, no games right now.\n\n"
 267                 (void)write(2, MESG, sizeof(MESG) - 1);
 268                 while ((n = read(fd, buf, sizeof(buf))) > 0)
 269                         (void)write(2, buf, n);
 270                 exit(1);
 271         }
 272 }
 273
 274 /*
 275  * hour --
 276  *      print out the hour in human form
 277  */
 278 hour(h)
 279         int h;
 280 {
 281         switch(h) {
 282         case 0:
 283                 fputs("midnight", stderr);
 284                 break;
 285         case 12:
 286                 fputs("noon", stderr);
 287                 break;
 288         default:
 289                 if (h > 12)
 290                         fprintf(stderr, "%dpm", h - 12);
 291                 else
 292                         fprintf(stderr, "%dam", h);
 293         }
 294 }
 295
 296 #ifdef LOG
 297 /*
 298  * logfile --
 299  *      log play of game
 300  */
 301 logfile()
 302 {
 303         struct passwd *pw, *getpwuid();
 304         FILE *lp;
 305         uid_t uid;
 306         int lock_cnt;
 307         char *ctime();
 308
 309         if (lp = fopen(_PATH_LOG, "a")) {
 310                 for (lock_cnt = 0;; ++lock_cnt) {
 311                         if (!flock(fileno(lp), LOCK_EX))
 312                                 break;
 313                         if (lock_cnt == 4) {
 314                                 perror("dm: log lock");
 315                                 (void)fclose(lp);
 316                                 return;
 317                         }
 318                         sleep((u_int)1);
 319                 }
 320                 if (pw = getpwuid(uid = getuid()))
 321                         fputs(pw->pw_name, lp);
 322                 else
 323                         fprintf(lp, "%u", uid);
 324                 fprintf(lp, "\t%s\t%s\t%s", game, gametty, ctime(&now));
 325                 (void)fclose(lp);
 326                 (void)flock(fileno(lp), LOCK_UN);
 327         }
 328 }
 329 #endif /* LOG */