random.c revision 181409 
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#if 0
38#ifndef lint
39static const char copyright[] =
40"@(#) Copyright (c) 1994\n\
41	The Regents of the University of California.  All rights reserved.\n";
42#endif /* not lint */
43
44#ifndef lint
45static const char sccsid[] = "@(#)random.c	8.5 (Berkeley) 4/5/94";
46#endif /* not lint */
47#endif
48#include <sys/cdefs.h>
49__FBSDID("$FreeBSD: head/games/random/random.c 181409 2008-08-08 01:02:30Z ache $");
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 <locale.h>
58#include <stdio.h>
59#include <stdlib.h>
60#include <string.h>
61#include <time.h>
62#include <unistd.h>
63
64#include "randomize_fd.h"
65
66static void usage(void);
67
68int
69main(int argc, char *argv[])
70{
71	double denom;
72	int ch, fd, random_exit, randomize_lines, random_type, ret,
73		selected, unique_output, unbuffer_output;
74	char *ep;
75	const char *filename;
76
77	denom = 0;
78	filename = "/dev/fd/0";
79	random_type = RANDOM_TYPE_UNSET;
80	random_exit = randomize_lines = random_type = unbuffer_output = 0;
81	unique_output = 1;
82
83	(void)setlocale(LC_CTYPE, "");
84
85	while ((ch = getopt(argc, argv, "ef:hlruUw")) != -1)
86		switch (ch) {
87		case 'e':
88			random_exit = 1;
89			break;
90		case 'f':
91			randomize_lines = 1;
92			if (strcmp(optarg, "-") != 0)
93				filename = optarg;
94			break;
95		case 'l':
96			randomize_lines = 1;
97			random_type = RANDOM_TYPE_LINES;
98			break;
99		case 'r':
100			unbuffer_output = 1;
101			break;
102		case 'u':
103			randomize_lines = 1;
104			unique_output = 1;
105			break;
106		case 'U':
107			randomize_lines = 1;
108			unique_output = 0;
109			break;
110		case 'w':
111			randomize_lines = 1;
112			random_type = RANDOM_TYPE_WORDS;
113			break;
114		default:
115		case '?':
116			usage();
117			/* NOTREACHED */
118		}
119
120	argc -= optind;
121	argv += optind;
122
123	switch (argc) {
124	case 0:
125		denom = (randomize_lines ? 1 : 2);
126		break;
127	case 1:
128		errno = 0;
129		denom = strtod(*argv, &ep);
130		if (errno == ERANGE)
131			err(1, "%s", *argv);
132		if (denom <= 0 || *ep != '\0')
133			errx(1, "denominator is not valid.");
134		if (random_exit && denom > 256)
135			errx(1, "denominator must be <= 256 for random exit.");
136		break;
137	default:
138		usage();
139		/* NOTREACHED */
140	}
141
142	srandomdev();
143
144	/*
145	 * Act as a filter, randomly choosing lines of the standard input
146	 * to write to the standard output.
147	 */
148	if (unbuffer_output)
149		setbuf(stdout, NULL);
150
151	/*
152	 * Act as a filter, randomizing lines read in from a given file
153	 * descriptor and write the output to standard output.
154	 */
155	if (randomize_lines) {
156		if ((fd = open(filename, O_RDONLY, 0)) < 0)
157			err(1, "%s", filename);
158		ret = randomize_fd(fd, random_type, unique_output, denom);
159		if (!random_exit)
160			return(ret);
161	}
162
163	/* Compute a random exit status between 0 and denom - 1. */
164	if (random_exit)
165		return (int)(denom * random() / ((double)RAND_MAX + 1));
166
167	/*
168	 * Select whether to print the first line.  (Prime the pump.)
169	 * We find a random number between 0 and denom - 1 and, if it's
170	 * 0 (which has a 1 / denom chance of being true), we select the
171	 * line.
172	 */
173	selected = (int)(denom * random() / ((double)RAND_MAX + 1)) == 0;
174	while ((ch = getchar()) != EOF) {
175		if (selected)
176			(void)putchar(ch);
177		if (ch == '\n') {
178			/* End of that line.  See if we got an error. */
179			if (ferror(stdout))
180				err(2, "stdout");
181
182			/* Now see if the next line is to be printed. */
183			selected = (int)(denom * random() / ((double)RAND_MAX + 1)) == 0;
184		}
185	}
186	if (ferror(stdin))
187		err(2, "stdin");
188	exit (0);
189}
190
191static void
192usage(void)
193{
194
195	fprintf(stderr, "usage: random [-elrUuw] [-f filename] [denominator]\n");
196	exit(1);
197}
198