xref: /freebsd/usr.bin/random/random.c (revision e17f5b1d307b7b8910d67883e57a9604305906d5)
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 <stdbool.h>
55 #include <stdint.h>
56 #include <stdio.h>
57 #include <stdlib.h>
58 #include <string.h>
59 #include <time.h>
60 #include <unistd.h>
61 
62 #include "randomize_fd.h"
63 
64 static void usage(void);
65 
66 int
67 main(int argc, char *argv[])
68 {
69 	double denom;
70 	int ch, fd, random_exit, randomize_lines, random_type, ret,
71 	    unique_output, unbuffer_output;
72 	bool selected;
73 	char *ep;
74 	const char *filename;
75 
76 	denom = 0.;
77 	filename = "/dev/fd/0";
78 	random_type = RANDOM_TYPE_UNSET;
79 	random_exit = randomize_lines = unbuffer_output = 0;
80 	unique_output = 1;
81 
82 	(void)setlocale(LC_CTYPE, "");
83 
84 	while ((ch = getopt(argc, argv, "ef:hlruUw")) != -1)
85 		switch (ch) {
86 		case 'e':
87 			random_exit = 1;
88 			break;
89 		case 'f':
90 			randomize_lines = 1;
91 			if (strcmp(optarg, "-") != 0)
92 				filename = optarg;
93 			break;
94 		case 'l':
95 			randomize_lines = 1;
96 			random_type = RANDOM_TYPE_LINES;
97 			break;
98 		case 'r':
99 			unbuffer_output = 1;
100 			break;
101 		case 'u':
102 			randomize_lines = 1;
103 			unique_output = 1;
104 			break;
105 		case 'U':
106 			randomize_lines = 1;
107 			unique_output = 0;
108 			break;
109 		case 'w':
110 			randomize_lines = 1;
111 			random_type = RANDOM_TYPE_WORDS;
112 			break;
113 		default:
114 		case '?':
115 			usage();
116 			/* NOTREACHED */
117 		}
118 
119 	argc -= optind;
120 	argv += optind;
121 
122 	switch (argc) {
123 	case 0:
124 		denom = (randomize_lines ? 1. : 2.);
125 		break;
126 	case 1:
127 		errno = 0;
128 		denom = strtod(*argv, &ep);
129 		if (errno == ERANGE)
130 			err(1, "%s", *argv);
131 		if (denom < 1. || *ep != '\0')
132 			errx(1, "denominator is not valid.");
133 		if (random_exit && denom > 256.)
134 			errx(1, "denominator must be <= 256 for random exit.");
135 		break;
136 	default:
137 		usage();
138 		/* NOTREACHED */
139 	}
140 
141 	/*
142 	 * Act as a filter, randomly choosing lines of the standard input
143 	 * to write to the standard output.
144 	 */
145 	if (unbuffer_output)
146 		setbuf(stdout, NULL);
147 
148 	/*
149 	 * Act as a filter, randomizing lines read in from a given file
150 	 * descriptor and write the output to standard output.
151 	 */
152 	if (randomize_lines) {
153 		if ((fd = open(filename, O_RDONLY, 0)) < 0)
154 			err(1, "%s", filename);
155 		ret = randomize_fd(fd, random_type, unique_output, denom);
156 		if (!random_exit)
157 			return(ret);
158 	}
159 
160 	/* Compute a random exit status between 0 and denom - 1. */
161 	if (random_exit)
162 		return (arc4random_uniform(denom));
163 
164 	/*
165 	 * Filter stdin, selecting lines with probability 1/denom, one
166 	 * character at a time.
167 	 */
168 	do {
169 		selected = random_uniform_denom(denom);
170 		if (selected) {
171 			while ((ch = getchar()) != EOF) {
172 				putchar(ch);
173 				if (ch == '\n')
174 					break;
175 			}
176 		} else {
177 			while ((ch = getchar()) != EOF)
178 				if (ch == '\n')
179 					break;
180 		}
181 		if (ferror(stdout))
182 			err(2, "stdout");
183 	} while (ch != EOF);
184 	if (ferror(stdin))
185 		err(2, "stdin");
186 	exit (0);
187 }
188 
189 static void
190 usage(void)
191 {
192 
193 	fprintf(stderr, "usage: random [-elrUuw] [-f filename] [denominator]\n");
194 	exit(1);
195 }
196