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