dm/dm.c

   1 /*      $NetBSD: dm.c,v 1.6 1997/04/21 11:11:47 mrg 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. All advertising materials mentioning features or use of this software
  16  *    must display the following acknowledgement:
  17  *      This product includes software developed by the University of
  18  *      California, Berkeley and its contributors.
  19  * 4. Neither the name of the University nor the names of its contributors
  20  *    may be used to endorse or promote products derived from this software
  21  *    without specific prior written permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  33  * SUCH DAMAGE.
  34  */
  35
  36 #ifndef lint
  37 static char copyright[] =
  38 "@(#) Copyright (c) 1987, 1993\n\
  39         The Regents of the University of California.  All rights reserved.\n";
  40 #endif /* not lint */
  41
  42 #ifndef lint
  43 #if 0
  44 static char sccsid[] = "@(#)dm.c        8.1 (Berkeley) 5/31/93";
  45 #else
  46 static char rcsid[] = "$NetBSD: dm.c,v 1.6 1997/04/21 11:11:47 mrg Exp $";
  47 #endif
  48 #endif /* not lint */
  49
  50 #include <sys/param.h>
  51 #include <sys/file.h>
  52 #include <sys/time.h>
  53 #include <sys/resource.h>
  54
  55 #include <ctype.h>
  56 #include <nlist.h>
  57 #include <pwd.h>
  58 #include <stdio.h>
  59 #include <string.h>
  60 #include <time.h>
  61 #include <unistd.h>
  62 #include <utmp.h>
  63 #include <errno.h>
  64
  65 #include "pathnames.h"
  66
  67 static time_t   now;                    /* current time value */
  68 static int      priority = 0;           /* priority game runs at */
  69 static char     *game,                  /* requested game */
  70                 *gametty;               /* from tty? */
  71
  72 int
  73 main(argc, argv)
  74         int argc;
  75         char *argv[];
  76 {
  77         char *cp;
  78
  79         nogamefile();
  80         game = (cp = rindex(*argv, '/')) ? ++cp : *argv;
  81
  82         if (!strcmp(game, "dm"))
  83                 exit(0);
  84
  85         gametty = ttyname(0);
  86         (void)time(&now);
  87         read_config();
  88 #ifdef LOG
  89         logfile();
  90 #endif
  91         play(argv);
  92         /*NOTREACHED*/
  93 }
  94
  95 /*
  96  * play --
  97  *      play the game
  98  */
  99 play(args)
 100         char **args;
 101 {
 102         char pbuf[MAXPATHLEN];
 103
 104         (void)strncpy(pbuf, _PATH_HIDE, sizeof(pbuf) - 1);
 105         (void)strncpy(pbuf + sizeof(_PATH_HIDE) - 1, game,
 106             sizeof(pbuf) - sizeof(_PATH_HIDE) - 1);
 107         pbuf[sizeof(pbuf) - 1] = '\0';
 108         if (priority > 0)       /* < 0 requires root */
 109                 (void)setpriority(PRIO_PROCESS, 0, priority);
 110         setgid(getgid());       /* we run setgid kmem; lose it */
 111         execv(pbuf, args);
 112         (void)fprintf(stderr, "dm: %s: %s\n", pbuf, strerror(errno));
 113         exit(1);
 114 }
 115
 116 /*
 117  * read_config --
 118  *      read through config file, looking for key words.
 119  */
 120 read_config()
 121 {
 122         FILE *cfp;
 123         char lbuf[BUFSIZ], f1[40], f2[40], f3[40], f4[40], f5[40];
 124
 125         if (!(cfp = fopen(_PATH_CONFIG, "r")))
 126                 return;
 127         while (fgets(lbuf, sizeof(lbuf), cfp))
 128                 switch(*lbuf) {
 129                 case 'b':               /* badtty */
 130                         if (sscanf(lbuf, "%s%s", f1, f2) != 2 ||
 131                             strcasecmp(f1, "badtty"))
 132                                 break;
 133                         c_tty(f2);
 134                         break;
 135                 case 'g':               /* game */
 136                         if (sscanf(lbuf, "%s%s%s%s%s",
 137                             f1, f2, f3, f4, f5) != 5 || strcasecmp(f1, "game"))
 138                                 break;
 139                         c_game(f2, f3, f4, f5);
 140                         break;
 141                 case 't':               /* time */
 142                         if (sscanf(lbuf, "%s%s%s%s", f1, f2, f3, f4) != 4 ||
 143                             strcasecmp(f1, "time"))
 144                                 break;
 145                         c_day(f2, f3, f4);
 146                 }
 147         (void)fclose(cfp);
 148 }
 149
 150 /*
 151  * c_day --
 152  *      if day is today, see if okay to play
 153  */
 154 c_day(s_day, s_start, s_stop)
 155         char *s_day, *s_start, *s_stop;
 156 {
 157         static char *days[] = {
 158                 "sunday", "monday", "tuesday", "wednesday",
 159                 "thursday", "friday", "saturday",
 160         };
 161         static struct tm *ct;
 162         int start, stop;
 163
 164         if (!ct)
 165                 ct = localtime(&now);
 166         if (strcasecmp(s_day, days[ct->tm_wday]))
 167                 return;
 168         if (!isdigit(*s_start) || !isdigit(*s_stop))
 169                 return;
 170         start = atoi(s_start);
 171         stop = atoi(s_stop);
 172         if (ct->tm_hour >= start && ct->tm_hour < stop) {
 173                 fputs("dm: Sorry, games are not available from ", stderr);
 174                 hour(start);
 175                 fputs(" to ", stderr);
 176                 hour(stop);
 177                 fputs(" today.\n", stderr);
 178                 exit(0);
 179         }
 180 }
 181
 182 /*
 183  * c_tty --
 184  *      decide if this tty can be used for games.
 185  */
 186 c_tty(tty)
 187         char *tty;
 188 {
 189         static int first = 1;
 190         static char *p_tty;
 191
 192         if (first) {
 193                 p_tty = rindex(gametty, '/');
 194                 first = 0;
 195         }
 196
 197         if (!strcmp(gametty, tty) || p_tty && !strcmp(p_tty, tty)) {
 198                 fprintf(stderr, "dm: Sorry, you may not play games on %s.\n", gametty);
 199                 exit(0);
 200         }
 201 }
 202
 203 /*
 204  * c_game --
 205  *      see if game can be played now.
 206  */
 207 c_game(s_game, s_load, s_users, s_priority)
 208         char *s_game, *s_load, *s_users, *s_priority;
 209 {
 210         static int found;
 211         double load();
 212
 213         if (found)
 214                 return;
 215         if (strcmp(game, s_game) && strcasecmp("default", s_game))
 216                 return;
 217         ++found;
 218         if (isdigit(*s_load) && atoi(s_load) < load()) {
 219                 fputs("dm: Sorry, the load average is too high right now.\n", stderr);
 220                 exit(0);
 221         }
 222         if (isdigit(*s_users) && atoi(s_users) <= users()) {
 223                 fputs("dm: Sorry, there are too many users logged on right now.\n", stderr);
 224                 exit(0);
 225         }
 226         if (isdigit(*s_priority))
 227                 priority = atoi(s_priority);
 228 }
 229
 230 /*
 231  * load --
 232  *      return 15 minute load average
 233  */
 234 double
 235 load()
 236 {
 237         double avenrun[3];
 238
 239         if (getloadavg(avenrun, sizeof(avenrun)/sizeof(avenrun[0])) < 0) {
 240                 fputs("dm: getloadavg() failed.\n", stderr);
 241                 exit(1);
 242         }
 243         return(avenrun[2]);
 244 }
 245
 246 /*
 247  * users --
 248  *      return current number of users
 249  *      todo: check idle time; if idle more than X minutes, don't
 250  *      count them.
 251  */
 252 users()
 253 {
 254
 255         register int nusers, utmp;
 256         struct utmp buf;
 257
 258         if ((utmp = open(_PATH_UTMP, O_RDONLY, 0)) < 0) {
 259                 (void)fprintf(stderr, "dm: %s: %s\n",
 260                     _PATH_UTMP, strerror(errno));
 261                 exit(1);
 262         }
 263         for (nusers = 0; read(utmp, (char *)&buf, sizeof(struct utmp)) > 0;)
 264                 if (buf.ut_name[0] != '\0')
 265                         ++nusers;
 266         return(nusers);
 267 }
 268
 269 nogamefile()
 270 {
 271         register int fd, n;
 272         char buf[BUFSIZ];
 273
 274         if ((fd = open(_PATH_NOGAMES, O_RDONLY, 0)) >= 0) {
 275 #define MESG    "Sorry, no games right now.\n\n"
 276                 (void)write(2, MESG, sizeof(MESG) - 1);
 277                 while ((n = read(fd, buf, sizeof(buf))) > 0)
 278                         (void)write(2, buf, n);
 279                 exit(1);
 280         }
 281 }
 282
 283 /*
 284  * hour --
 285  *      print out the hour in human form
 286  */
 287 hour(h)
 288         int h;
 289 {
 290         switch(h) {
 291         case 0:
 292                 fputs("midnight", stderr);
 293                 break;
 294         case 12:
 295                 fputs("noon", stderr);
 296                 break;
 297         default:
 298                 if (h > 12)
 299                         fprintf(stderr, "%dpm", h - 12);
 300                 else
 301                         fprintf(stderr, "%dam", h);
 302         }
 303 }
 304
 305 #ifdef LOG
 306 /*
 307  * logfile --
 308  *      log play of game
 309  */
 310 logfile()
 311 {
 312         struct passwd *pw;
 313         FILE *lp;
 314         uid_t uid;
 315         int lock_cnt;
 316
 317         if (lp = fopen(_PATH_LOG, "a")) {
 318                 for (lock_cnt = 0;; ++lock_cnt) {
 319                         if (!flock(fileno(lp), LOCK_EX))
 320                                 break;
 321                         if (lock_cnt == 4) {
 322                                 perror("dm: log lock");
 323                                 (void)fclose(lp);
 324                                 return;
 325                         }
 326                         sleep((u_int)1);
 327                 }
 328                 if (pw = getpwuid(uid = getuid()))
 329                         fputs(pw->pw_name, lp);
 330                 else
 331                         fprintf(lp, "%u", uid);
 332                 fprintf(lp, "\t%s\t%s\t%s", game, gametty, ctime(&now));
 333                 (void)fclose(lp);
 334                 (void)flock(fileno(lp), LOCK_UN);
 335         }
 336 }
 337 #endif /* LOG */