xref: /freebsd/usr.bin/random/random.c (revision 162ae9c834f6d9f9cb443bd62cceb23e0b5fef48)
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 <stdint.h>
55 #include <stdio.h>
56 #include <stdlib.h>
57 #include <string.h>
58 #include <time.h>
59 #include <unistd.h>
60 
61 #include "randomize_fd.h"
62 
63 static void usage(void);
64 
65 int
66 main(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;
72 	const char *filename;
73 
74 	denom = 0;
75 	filename = "/dev/fd/0";
76 	random_type = RANDOM_TYPE_UNSET;
77 	random_exit = randomize_lines = unbuffer_output = 0;
78 	unique_output = 1;
79 
80 	(void)setlocale(LC_CTYPE, "");
81 
82 	while ((ch = getopt(argc, argv, "ef:hlruUw")) != -1)
83 		switch (ch) {
84 		case 'e':
85 			random_exit = 1;
86 			break;
87 		case 'f':
88 			randomize_lines = 1;
89 			if (strcmp(optarg, "-") != 0)
90 				filename = optarg;
91 			break;
92 		case 'l':
93 			randomize_lines = 1;
94 			random_type = RANDOM_TYPE_LINES;
95 			break;
96 		case 'r':
97 			unbuffer_output = 1;
98 			break;
99 		case 'u':
100 			randomize_lines = 1;
101 			unique_output = 1;
102 			break;
103 		case 'U':
104 			randomize_lines = 1;
105 			unique_output = 0;
106 			break;
107 		case 'w':
108 			randomize_lines = 1;
109 			random_type = RANDOM_TYPE_WORDS;
110 			break;
111 		default:
112 		case '?':
113 			usage();
114 			/* NOTREACHED */
115 		}
116 
117 	argc -= optind;
118 	argv += optind;
119 
120 	switch (argc) {
121 	case 0:
122 		denom = (randomize_lines ? 1 : 2);
123 		break;
124 	case 1:
125 		errno = 0;
126 		denom = strtod(*argv, &ep);
127 		if (errno == ERANGE)
128 			err(1, "%s", *argv);
129 		if (denom <= 0 || *ep != '\0')
130 			errx(1, "denominator is not valid.");
131 		if (random_exit && denom > 256)
132 			errx(1, "denominator must be <= 256 for random exit.");
133 		break;
134 	default:
135 		usage();
136 		/* NOTREACHED */
137 	}
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", filename);
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 (arc4random_uniform(denom));
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 = (arc4random_uniform(denom) == 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 = (arc4random_uniform(denom) == 0);
179 		}
180 	}
181 	if (ferror(stdin))
182 		err(2, "stdin");
183 	exit (0);
184 }
185 
186 static void
187 usage(void)
188 {
189 
190 	fprintf(stderr, "usage: random [-elrUuw] [-f filename] [denominator]\n");
191 	exit(1);
192 }
193