games/random/random.c

   1 /*
   2  * Copyright (c) 1994
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * This code is derived from software contributed to Berkeley by
   6  * Guy Harris at Network Appliance Corp.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. All advertising materials mentioning features or use of this software
  17  *    must display the following acknowledgement:
  18  *      This product includes software developed by the University of
  19  *      California, Berkeley and its contributors.
  20  * 4. Neither the name of the University nor the names of its contributors
  21  *    may be used to endorse or promote products derived from this software
  22  *    without specific prior written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  34  * SUCH DAMAGE.
  35  *
  36  * @(#) Copyright (c) 1994 The Regents of the University of California.  All rights reserved.
  37  * @(#)random.c 8.5 (Berkeley) 4/5/94
  38  * $FreeBSD: src/games/random/random.c,v 1.17 2005/02/09 18:22:15 ru Exp $
  39  * $DragonFly: src/games/random/random.c,v 1.4 2005/03/02 06:59:23 cpressey Exp $
  40  */
  41
  42 #include <sys/types.h>
  43
  44 #include <err.h>
  45 #include <errno.h>
  46 #include <fcntl.h>
  47 #include <limits.h>
  48 #include <stdio.h>
  49 #include <stdlib.h>
  50 #include <string.h>
  51 #include <time.h>
  52 #include <unistd.h>
  53
  54 #include "randomize_fd.h"
  55
  56 static void usage(void);
  57
  58 int
  59 main(int argc, char *argv[])
  60 {
  61         double denom;
  62         int ch, fd, random_exit, randomize_lines, random_type, ret,
  63                 selected, unique_output, unbuffer_output;
  64         char *ep;
  65         const char *filename;
  66
  67         denom = 0;
  68         filename = "/dev/fd/0";
  69         random_type = RANDOM_TYPE_UNSET;
  70         random_exit = randomize_lines = random_type = unbuffer_output = 0;
  71         unique_output = 1;
  72         while ((ch = getopt(argc, argv, "ef:hlruUw")) != -1)
  73                 switch (ch) {
  74                 case 'e':
  75                         random_exit = 1;
  76                         break;
  77                 case 'f':
  78                         randomize_lines = 1;
  79                         if (strcmp(optarg, "-") != 0)
  80                                 filename = optarg;
  81                         break;
  82                 case 'l':
  83                         randomize_lines = 1;
  84                         random_type = RANDOM_TYPE_LINES;
  85                         break;
  86                 case 'r':
  87                         unbuffer_output = 1;
  88                         break;
  89                 case 'u':
  90                         randomize_lines = 1;
  91                         unique_output = 1;
  92                         break;
  93                 case 'U':
  94                         randomize_lines = 1;
  95                         unique_output = 0;
  96                         break;
  97                 case 'w':
  98                         randomize_lines = 1;
  99                         random_type = RANDOM_TYPE_WORDS;
 100                         break;
 101                 default:
 102                 case '?':
 103                         usage();
 104                         /* NOTREACHED */
 105                 }
 106
 107         argc -= optind;
 108         argv += optind;
 109
 110         switch (argc) {
 111         case 0:
 112                 denom = (randomize_lines ? 1 : 2);
 113                 break;
 114         case 1:
 115                 errno = 0;
 116                 denom = strtod(*argv, &ep);
 117                 if (errno == ERANGE)
 118                         err(1, "%s", *argv);
 119                 if (denom <= 0 || *ep != '\0')
 120                         errx(1, "denominator is not valid.");
 121                 if (random_exit && denom > 255)
 122                         errx(1, "denominator must be <= 255 for random exit.");
 123                 break;
 124         default:
 125                 usage();
 126                 /* NOTREACHED */
 127         }
 128
 129         srandomdev();
 130
 131         /*
 132          * Act as a filter, randomly choosing lines of the standard input
 133          * to write to the standard output.
 134          */
 135         if (unbuffer_output)
 136                 setbuf(stdout, NULL);
 137
 138         /*
 139          * Act as a filter, randomizing lines read in from a given file
 140          * descriptor and write the output to standard output.
 141          */
 142         if (randomize_lines) {
 143                 if ((fd = open(filename, O_RDONLY, 0)) < 0)
 144                         err(1, "%s", filename);
 145                 ret = randomize_fd(fd, random_type, unique_output, denom);
 146                 if (!random_exit)
 147                         return(ret);
 148         }
 149
 150         /* Compute a random exit status between 0 and denom - 1. */
 151         if (random_exit)
 152                 return (int)((denom * random()) / LONG_MAX);
 153
 154         /*
 155          * Select whether to print the first line.  (Prime the pump.)
 156          * We find a random number between 0 and denom - 1 and, if it's
 157          * 0 (which has a 1 / denom chance of being true), we select the
 158          * line.
 159          */
 160         selected = (int)(denom * random() / LONG_MAX) == 0;
 161         while ((ch = getchar()) != EOF) {
 162                 if (selected)
 163                         (void)putchar(ch);
 164                 if (ch == '\n') {
 165                         /* End of that line.  See if we got an error. */
 166                         if (ferror(stdout))
 167                                 err(2, "stdout");
 168
 169                         /* Now see if the next line is to be printed. */
 170                         selected = (int)(denom * random() / LONG_MAX) == 0;
 171                 }
 172         }
 173         if (ferror(stdin))
 174                 err(2, "stdin");
 175         exit (0);
 176 }
 177
 178 static void
 179 usage(void)
 180 {
 181
 182         fprintf(stderr, "usage: random [-elrUuw] [-f filename] [denominator]\n");
 183         exit(1);
 184 }