random.c revision 209157 
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
33#if 0
34#ifndef lint
35static const char copyright[] =
36"@(#) Copyright (c) 1994\n\
37	The Regents of the University of California.  All rights reserved.\n";
38#endif /* not lint */
39
40#ifndef lint
41static const char sccsid[] = "@(#)random.c	8.5 (Berkeley) 4/5/94";
42#endif /* not lint */
43#endif
44#include <sys/cdefs.h>
45__FBSDID("$FreeBSD: head/games/random/random.c 209157 2010-06-14 13:03:25Z uqs $");
46
47#include <sys/types.h>
48
49#include <err.h>
50#include <errno.h>
51#include <fcntl.h>
52#include <limits.h>
53#include <locale.h>
54#include <stdio.h>
55#include <stdlib.h>
56#include <string.h>
57#include <time.h>
58#include <unistd.h>
59
60#include "randomize_fd.h"
61
62static void usage(void);
63
64int
65main(int argc, char *argv[])
66{
67	double denom;
68	int ch, fd, random_exit, randomize_lines, random_type, ret,
69		selected, unique_output, unbuffer_output;
70	char *ep;
71	const char *filename;
72
73	denom = 0;
74	filename = "/dev/fd/0";
75	random_type = RANDOM_TYPE_UNSET;
76	random_exit = randomize_lines = unbuffer_output = 0;
77	unique_output = 1;
78
79	(void)setlocale(LC_CTYPE, "");
80
81	while ((ch = getopt(argc, argv, "ef:hlruUw")) != -1)
82		switch (ch) {
83		case 'e':
84			random_exit = 1;
85			break;
86		case 'f':
87			randomize_lines = 1;
88			if (strcmp(optarg, "-") != 0)
89				filename = optarg;
90			break;
91		case 'l':
92			randomize_lines = 1;
93			random_type = RANDOM_TYPE_LINES;
94			break;
95		case 'r':
96			unbuffer_output = 1;
97			break;
98		case 'u':
99			randomize_lines = 1;
100			unique_output = 1;
101			break;
102		case 'U':
103			randomize_lines = 1;
104			unique_output = 0;
105			break;
106		case 'w':
107			randomize_lines = 1;
108			random_type = RANDOM_TYPE_WORDS;
109			break;
110		default:
111		case '?':
112			usage();
113			/* NOTREACHED */
114		}
115
116	argc -= optind;
117	argv += optind;
118
119	switch (argc) {
120	case 0:
121		denom = (randomize_lines ? 1 : 2);
122		break;
123	case 1:
124		errno = 0;
125		denom = strtod(*argv, &ep);
126		if (errno == ERANGE)
127			err(1, "%s", *argv);
128		if (denom <= 0 || *ep != '\0')
129			errx(1, "denominator is not valid.");
130		if (random_exit && denom > 256)
131			errx(1, "denominator must be <= 256 for random exit.");
132		break;
133	default:
134		usage();
135		/* NOTREACHED */
136	}
137
138	srandomdev();
139
140	/*
141	 * Act as a filter, randomly choosing lines of the standard input
142	 * to write to the standard output.
143	 */
144	if (unbuffer_output)
145		setbuf(stdout, NULL);
146
147	/*
148	 * Act as a filter, randomizing lines read in from a given file
149	 * descriptor and write the output to standard output.
150	 */
151	if (randomize_lines) {
152		if ((fd = open(filename, O_RDONLY, 0)) < 0)
153			err(1, "%s", filename);
154		ret = randomize_fd(fd, random_type, unique_output, denom);
155		if (!random_exit)
156			return(ret);
157	}
158
159	/* Compute a random exit status between 0 and denom - 1. */
160	if (random_exit)
161		return (int)(denom * random() / RANDOM_MAX_PLUS1);
162
163	/*
164	 * Select whether to print the first line.  (Prime the pump.)
165	 * We find a random number between 0 and denom - 1 and, if it's
166	 * 0 (which has a 1 / denom chance of being true), we select the
167	 * line.
168	 */
169	selected = (int)(denom * random() / RANDOM_MAX_PLUS1) == 0;
170	while ((ch = getchar()) != EOF) {
171		if (selected)
172			(void)putchar(ch);
173		if (ch == '\n') {
174			/* End of that line.  See if we got an error. */
175			if (ferror(stdout))
176				err(2, "stdout");
177
178			/* Now see if the next line is to be printed. */
179			selected = (int)(denom * random() /
180				RANDOM_MAX_PLUS1) == 0;
181		}
182	}
183	if (ferror(stdin))
184		err(2, "stdin");
185	exit (0);
186}
187
188static void
189usage(void)
190{
191
192	fprintf(stderr, "usage: random [-elrUuw] [-f filename] [denominator]\n");
193	exit(1);
194}
195