random.c revision 110723 
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
37#ifndef lint
38static const char copyright[] =
39"@(#) Copyright (c) 1994\n\
40	The Regents of the University of California.  All rights reserved.\n";
41#endif /* not lint */
42
43#ifndef lint
44#if 0
45static char sccsid[] = "@(#)random.c	8.5 (Berkeley) 4/5/94";
46#endif
47static const char rcsid[] =
48 "$FreeBSD: head/games/random/random.c 110723 2003-02-11 19:32:18Z seanc $";
49#endif /* not lint */
50
51#include <sys/types.h>
52
53#include <err.h>
54#include <errno.h>
55#include <fcntl.h>
56#include <limits.h>
57#include <stdio.h>
58#include <stdlib.h>
59#include <time.h>
60#include <unistd.h>
61#include "randomize_fd.h"
62
63void usage(void);
64
65int
66main(int argc, char **argv)
67{
68	double denom;
69	int ch, fd, random_exit, randomize_lines, random_type, ret,
70		selected, unique_output, unbuffer_output;
71	char *ep, *filename;
72
73	denom = 0;
74	filename = NULL;
75	random_type = RANDOM_TYPE_UNSET;
76	random_exit = randomize_lines = random_type = unbuffer_output = 0;
77	unique_output = 1;
78	while ((ch = getopt(argc, argv, "ef:hlruUw")) != -1)
79		switch (ch) {
80		case 'e':
81			random_exit = 1;
82			break;
83		case 'f':
84			randomize_lines = 1;
85			if (!strcmp(optarg, "-"))
86				filename = strdup("/dev/fd/0");
87			else
88				filename = optarg;
89			break;
90		case 'l':
91			randomize_lines = 1;
92			random_type = RANDOM_TYPE_LINES;
93			break;
94		case 'r':
95			unbuffer_output = 1;
96			break;
97		case 'u':
98			randomize_lines = 1;
99			unique_output = 1;
100			break;
101		case 'U':
102			randomize_lines = 1;
103			unique_output = 0;
104			break;
105		case 'w':
106			randomize_lines = 1;
107			random_type = RANDOM_TYPE_WORDS;
108			break;
109		default:
110		case '?':
111			usage();
112			/* NOTREACHED */
113		}
114
115	argc -= optind;
116	argv += optind;
117
118	switch (argc) {
119	case 0:
120		denom = (randomize_lines ? 1 : 2);
121		break;
122	case 1:
123		errno = 0;
124		denom = strtod(*argv, &ep);
125		if (errno == ERANGE)
126			err(1, "%s", *argv);
127		if (denom <= 0 || *ep != '\0')
128			errx(1, "denominator is not valid.");
129		if (random_exit && denom > 255)
130			errx(1, "denominator must be <= 255 for random exit.");
131		break;
132	default:
133		usage();
134		/* NOTREACHED */
135	}
136
137	srandomdev();
138
139	/*
140	 * Act as a filter, randomly choosing lines of the standard input
141	 * to write to the standard output.
142	 */
143	if (unbuffer_output)
144		setbuf(stdout, NULL);
145
146	/*
147	 * Act as a filter, randomizing lines read in from a given file
148	 * descriptor and write the output to standard output.
149	 */
150	if (randomize_lines) {
151		if ((fd = open(filename, O_RDONLY, 0)) < 0)
152			err(1, "%s", optarg);
153		ret = randomize_fd(fd, random_type, unique_output, denom);
154		if (!random_exit)
155			return(ret);
156	}
157
158	/* Compute a random exit status between 0 and denom - 1. */
159	if (random_exit)
160		return ((denom * random()) / LONG_MAX);
161
162	/*
163	 * Select whether to print the first line.  (Prime the pump.)
164	 * We find a random number between 0 and denom - 1 and, if it's
165	 * 0 (which has a 1 / denom chance of being true), we select the
166	 * line.
167	 */
168	selected = (int)(denom * random() / LONG_MAX) == 0;
169	while ((ch = getchar()) != EOF) {
170		if (selected)
171			(void)putchar(ch);
172		if (ch == '\n') {
173			/* End of that line.  See if we got an error. */
174			if (ferror(stdout))
175				err(2, "stdout");
176
177			/* Now see if the next line is to be printed. */
178			selected = (int)(denom * random() / LONG_MAX) == 0;
179		}
180	}
181	if (ferror(stdin))
182		err(2, "stdin");
183	exit (0);
184}
185
186void
187usage()
188{
189
190	(void)fprintf(stderr, "usage: random [-elruUw] [-f filename] [denominator]\n");
191	exit(1);
192}
193