games/dm/dm.c

   1 /*
   2  * Copyright (c) 1987, 1993
   3  *      The Regents of the University of California.  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  * @(#) Copyright (c) 1987, 1993 The Regents of the University of California.  All rights reserved.
  34  * @(#)dm.c     8.1 (Berkeley) 5/31/93
  35  * $FreeBSD: src/games/dm/dm.c,v 1.8 1999/12/10 02:54:18 billf Exp $
  36  * $DragonFly: src/games/dm/dm.c,v 1.4 2006/08/08 17:05:14 pavalos Exp $
  37  */
  38
  39 #include <sys/param.h>
  40 #include <sys/file.h>
  41 #include <sys/time.h>
  42 #include <sys/resource.h>
  43
  44 #include <ctype.h>
  45 #include <errno.h>
  46 #include <nlist.h>
  47 #include <pwd.h>
  48 #include <stdio.h>
  49 #include <stdlib.h>
  50 #include <string.h>
  51 #include <time.h>
  52 #include <unistd.h>
  53 #include <utmp.h>
  54
  55 #include "pathnames.h"
  56
  57 static time_t   now;                    /* current time value */
  58 static int      priority = 0;           /* priority game runs at */
  59 static char     *game,                  /* requested game */
  60                 *gametty;               /* from tty? */
  61
  62 static void     c_day(char *, char *, char *);
  63 static void     c_tty(char *);
  64 static void     c_game(char *, char *, char *, char *);
  65 static void     hour(int);
  66 static double   load(void);
  67 static void     nogamefile(void);
  68 static void     play(char **);
  69 static void     read_config(void);
  70 static int      users(void);
  71 #ifdef LOG
  72 static void     logfile(void);
  73 #endif
  74
  75 int
  76 main(__unused int argc, char *argv[])
  77 {
  78         char *cp;
  79
  80         nogamefile();
  81         game = (cp = strrchr(*argv, '/')) ? ++cp : *argv;
  82
  83         if (!strcmp(game, "dm"))
  84                 exit(0);
  85
  86         gametty = ttyname(0);
  87         unsetenv("TZ");
  88         time(&now);
  89         read_config();
  90 #ifdef LOG
  91         logfile();
  92 #endif
  93         play(argv);
  94         /*NOTREACHED*/
  95         exit(EXIT_FAILURE);
  96 }
  97
  98 /*
  99  * play --
 100  *      play the game
 101  */
 102 static void
 103 play(char **args)
 104 {
 105         char pbuf[MAXPATHLEN];
 106
 107         if (sizeof(_PATH_HIDE) + strlen(game) > sizeof(pbuf)) {
 108                 fprintf(stderr, "dm: %s/%s: %s\n", _PATH_HIDE, game,
 109                         strerror(ENAMETOOLONG));
 110                 exit(1);
 111         }
 112         strcpy(pbuf, _PATH_HIDE);
 113         strcpy(pbuf + sizeof(_PATH_HIDE) - 1, game);
 114         if (priority > 0)       /* < 0 requires root */
 115                 setpriority(PRIO_PROCESS, 0, priority);
 116         execv(pbuf, args);
 117         fprintf(stderr, "dm: %s: %s\n", pbuf, strerror(errno));
 118         exit(1);
 119 }
 120
 121 /*
 122  * read_config --
 123  *      read through config file, looking for key words.
 124  */
 125 static void
 126 read_config(void)
 127 {
 128         FILE *cfp;
 129         char lbuf[BUFSIZ], f1[40], f2[40], f3[40], f4[40], f5[40];
 130
 131         if (!(cfp = fopen(_PATH_CONFIG, "r")))
 132                 return;
 133         while (fgets(lbuf, sizeof(lbuf), cfp))
 134                 switch(*lbuf) {
 135                 case 'b':               /* badtty */
 136                         if (sscanf(lbuf, "%s%s", f1, f2) != 2 ||
 137                             strcasecmp(f1, "badtty"))
 138                                 break;
 139                         c_tty(f2);
 140                         break;
 141                 case 'g':               /* game */
 142                         if (sscanf(lbuf, "%s%s%s%s%s",
 143                             f1, f2, f3, f4, f5) != 5 || strcasecmp(f1, "game"))
 144                                 break;
 145                         c_game(f2, f3, f4, f5);
 146                         break;
 147                 case 't':               /* time */
 148                         if (sscanf(lbuf, "%s%s%s%s", f1, f2, f3, f4) != 4 ||
 149                             strcasecmp(f1, "time"))
 150                                 break;
 151                         c_day(f2, f3, f4);
 152                 }
 153         fclose(cfp);
 154 }
 155
 156 /*
 157  * c_day --
 158  *      if day is today, see if okay to play
 159  */
 160 static void
 161 c_day(char *s_day, char *s_start, char *s_stop)
 162 {
 163         static const char *days[] = {
 164                 "sunday", "monday", "tuesday", "wednesday",
 165                 "thursday", "friday", "saturday",
 166         };
 167         static struct tm *ct;
 168         int start, stop;
 169
 170         if (!ct)
 171                 ct = localtime(&now);
 172         if (strcasecmp(s_day, days[ct->tm_wday]))
 173                 return;
 174         if (!isdigit(*s_start) || !isdigit(*s_stop))
 175                 return;
 176         start = atoi(s_start);
 177         stop = atoi(s_stop);
 178         if (ct->tm_hour >= start && ct->tm_hour < stop) {
 179                 fputs("dm: Sorry, games are not available from ", stderr);
 180                 hour(start);
 181                 fputs(" to ", stderr);
 182                 hour(stop);
 183                 fputs(" today.\n", stderr);
 184                 exit(0);
 185         }
 186 }
 187
 188 /*
 189  * c_tty --
 190  *      decide if this tty can be used for games.
 191  */
 192 static void
 193 c_tty(char *tty)
 194 {
 195         static int first = 1;
 196         static char *p_tty;
 197
 198         if (first) {
 199                 p_tty = strrchr(gametty, '/');
 200                 first = 0;
 201         }
 202
 203         if (!strcmp(gametty, tty) || (p_tty && !strcmp(p_tty, tty))) {
 204                 fprintf(stderr, "dm: Sorry, you may not play games on %s.\n", gametty);
 205                 exit(0);
 206         }
 207 }
 208
 209 /*
 210  * c_game --
 211  *      see if game can be played now.
 212  */
 213 static void
 214 c_game(char *s_game, char *s_load, char *s_users, 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(*s_load) && atoi(s_load) < load()) {
 224                 fputs("dm: Sorry, the load average is too high right now.\n", stderr);
 225                 exit(0);
 226         }
 227         if (isdigit(*s_users) && atoi(s_users) <= users()) {
 228                 fputs("dm: Sorry, there are too many users logged on right now.\n", stderr);
 229                 exit(0);
 230         }
 231         if (isdigit(*s_priority))
 232                 priority = atoi(s_priority);
 233 }
 234
 235 /*
 236  * load --
 237  *      return 15 minute load average
 238  */
 239 static double
 240 load(void)
 241 {
 242         double avenrun[3];
 243
 244         if (getloadavg(avenrun, sizeof(avenrun)/sizeof(avenrun[0])) < 0) {
 245                 fputs("dm: getloadavg() failed.\n", stderr);
 246                 exit(1);
 247         }
 248         return(avenrun[2]);
 249 }
 250
 251 /*
 252  * users --
 253  *      return current number of users
 254  *      todo: check idle time; if idle more than X minutes, don't
 255  *      count them.
 256  */
 257 static int
 258 users(void)
 259 {
 260
 261         int nusers, utmp;
 262         struct utmp buf;
 263
 264         if ((utmp = open(_PATH_UTMP, O_RDONLY, 0)) < 0) {
 265                 fprintf(stderr, "dm: %s: %s\n",
 266                     _PATH_UTMP, strerror(errno));
 267                 exit(1);
 268         }
 269         for (nusers = 0; read(utmp, (char *)&buf, sizeof(struct utmp)) > 0;)
 270                 if (buf.ut_name[0] != '\0')
 271                         ++nusers;
 272         return(nusers);
 273 }
 274
 275 static void
 276 nogamefile(void)
 277 {
 278         int fd, n;
 279         char buf[BUFSIZ];
 280
 281         if ((fd = open(_PATH_NOGAMES, O_RDONLY, 0)) >= 0) {
 282 #define MESG    "Sorry, no games right now.\n\n"
 283                 write(2, MESG, sizeof(MESG) - 1);
 284                 while ((n = read(fd, buf, sizeof(buf))) > 0)
 285                         write(2, buf, n);
 286                 exit(1);
 287         }
 288 }
 289
 290 /*
 291  * hour --
 292  *      print out the hour in human form
 293  */
 294 static void
 295 hour(int h)
 296 {
 297         switch(h) {
 298         case 0:
 299                 fputs("midnight", stderr);
 300                 break;
 301         case 12:
 302                 fputs("noon", stderr);
 303                 break;
 304         default:
 305                 if (h > 12)
 306                         fprintf(stderr, "%dpm", h - 12);
 307                 else
 308                         fprintf(stderr, "%dam", h);
 309         }
 310 }
 311
 312 #ifdef LOG
 313 /*
 314  * logfile --
 315  *      log play of game
 316  */
 317 static void
 318 logfile(void)
 319 {
 320         struct passwd *pw;
 321         FILE *lp;
 322         uid_t uid;
 323         int lock_cnt;
 324
 325         if (lp = fopen(_PATH_LOG, "a")) {
 326                 for (lock_cnt = 0;; ++lock_cnt) {
 327                         if (!flock(fileno(lp), LOCK_EX))
 328                                 break;
 329                         if (lock_cnt == 4) {
 330                                 perror("dm: log lock");
 331                                 fclose(lp);
 332                                 return;
 333                         }
 334                         sleep((u_int)1);
 335                 }
 336                 if (pw = getpwuid(uid = getuid()))
 337                         fputs(pw->pw_name, lp);
 338                 else
 339                         fprintf(lp, "%u", uid);
 340                 fprintf(lp, "\t%s\t%s\t%s", game, gametty, ctime(&now));
 341                 fclose(lp);
 342                 flock(fileno(lp), LOCK_UN);
 343         }
 344 }
 345 #endif /* LOG */