xref: /freebsd/usr.bin/random/random.c (revision f39bffc62c1395bde25d152c7f68fdf7cbaab414)
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
35 static 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
41 static const char sccsid[] = "@(#)random.c	8.5 (Berkeley) 4/5/94";
42 #endif /* not lint */
43 #endif
44 #include <sys/cdefs.h>
45 __FBSDID("$FreeBSD$");
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 
62 static void usage(void);
63 
64 int
65 main(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 
188 static void
189 usage(void)
190 {
191 
192 	fprintf(stderr, "usage: random [-elrUuw] [-f filename] [denominator]\n");
193 	exit(1);
194 }
195