1 /*
2 * Copyright (C) 2003 Sean Chittenden <seanc@FreeBSD.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27 #include <sys/types.h>
28 #include <sys/param.h>
29
30 #include <ctype.h>
31 #include <err.h>
32 #include <errno.h>
33 #include <stdbool.h>
34 #include <stdlib.h>
35 #include <stdint.h>
36 #include <stdio.h>
37 #include <string.h>
38 #include <unistd.h>
39
40 #include "randomize_fd.h"
41
42 static struct rand_node *rand_root;
43 static struct rand_node *rand_tail;
44
45 static struct rand_node *
rand_node_allocate(void)46 rand_node_allocate(void)
47 {
48 struct rand_node *n;
49
50 n = (struct rand_node *)malloc(sizeof(struct rand_node));
51 if (n == NULL)
52 err(1, "malloc");
53
54 n->len = 0;
55 n->cp = NULL;
56 n->next = NULL;
57 return(n);
58 }
59
60 static void
rand_node_free(struct rand_node * n)61 rand_node_free(struct rand_node *n)
62 {
63 if (n != NULL) {
64 if (n->cp != NULL)
65 free(n->cp);
66
67 free(n);
68 }
69 }
70
71 static void
rand_node_free_rec(struct rand_node * n)72 rand_node_free_rec(struct rand_node *n)
73 {
74 if (n != NULL) {
75 if (n->next != NULL)
76 rand_node_free_rec(n->next);
77
78 rand_node_free(n);
79 }
80 }
81
82 static void
rand_node_append(struct rand_node * n)83 rand_node_append(struct rand_node *n)
84 {
85 if (rand_root == NULL)
86 rand_root = rand_tail = n;
87 else {
88 rand_tail->next = n;
89 rand_tail = n;
90 }
91 }
92
93 int
randomize_fd(int fd,int type,int unique,double denom)94 randomize_fd(int fd, int type, int unique, double denom)
95 {
96 u_char *buf;
97 u_int slen;
98 u_long i, j, numnode, selected;
99 struct rand_node *n, *prev;
100 int bufleft, eof, fndstr, ret;
101 size_t bufc, buflen;
102 ssize_t len;
103
104 rand_root = rand_tail = NULL;
105 bufc = i = 0;
106 bufleft = eof = fndstr = numnode = 0;
107
108 if (type == RANDOM_TYPE_UNSET)
109 type = RANDOM_TYPE_LINES;
110
111 buflen = sizeof(u_char) * MAXBSIZE;
112 buf = (u_char *)malloc(buflen);
113 if (buf == NULL)
114 err(1, "malloc");
115
116 while (!eof) {
117 /* Check to see if we have bits in the buffer */
118 if (bufleft == 0) {
119 len = read(fd, buf, buflen);
120 if (len == -1)
121 err(1, "read");
122 else if (len == 0) {
123 eof++;
124 break;
125 } else if ((size_t)len < buflen)
126 buflen = (size_t)len;
127
128 bufleft = (int)len;
129 }
130
131 /* Look for a newline */
132 for (i = bufc; i <= buflen && bufleft >= 0; i++, bufleft--) {
133 if (i == buflen) {
134 if (fndstr) {
135 if (!eof) {
136 memmove(buf, &buf[bufc], i - bufc);
137 i -= bufc;
138 bufc = 0;
139 len = read(fd, &buf[i], buflen - i);
140 if (len == -1)
141 err(1, "read");
142 else if (len == 0) {
143 eof++;
144 break;
145 } else if (len < (ssize_t)(buflen - i))
146 buflen = i + (size_t)len;
147
148 bufleft = (int)len;
149 fndstr = 0;
150 }
151 } else {
152 buflen *= 2;
153 buf = (u_char *)realloc(buf, buflen);
154 if (buf == NULL)
155 err(1, "realloc");
156
157 if (!eof) {
158 len = read(fd, &buf[i], buflen - i);
159 if (len == -1)
160 err(1, "read");
161 else if (len == 0) {
162 eof++;
163 break;
164 } else if (len < (ssize_t)(buflen - i))
165 buflen = i + (size_t)len;
166
167 bufleft = (int)len;
168 }
169
170 }
171 }
172
173 if ((type == RANDOM_TYPE_LINES && buf[i] == '\n') ||
174 (type == RANDOM_TYPE_WORDS && isspace(buf[i])) ||
175 (eof && i == buflen - 1)) {
176 make_token:
177 if (numnode == UINT32_MAX - 1) {
178 errno = EFBIG;
179 err(1, "too many delimiters");
180 }
181 numnode++;
182 n = rand_node_allocate();
183 if (-1 != (int)i) {
184 slen = i - (u_long)bufc;
185 n->len = slen + 2;
186 n->cp = (u_char *)malloc(slen + 2);
187 if (n->cp == NULL)
188 err(1, "malloc");
189
190 memmove(n->cp, &buf[bufc], slen);
191 n->cp[slen] = buf[i];
192 n->cp[slen + 1] = '\0';
193 bufc = i + 1;
194 }
195 rand_node_append(n);
196 fndstr = 1;
197 }
198 }
199 }
200
201 /* Necessary evil to compensate for files that don't end with a newline */
202 if (bufc != i) {
203 i--;
204 goto make_token;
205 }
206
207 (void)close(fd);
208
209 free(buf);
210
211 for (i = numnode; i > 0; i--) {
212 selected = arc4random_uniform(numnode);
213
214 for (j = 0, prev = n = rand_root; n != NULL; j++, prev = n, n = n->next) {
215 if (j == selected) {
216 if (n->cp == NULL)
217 break;
218
219 if (random_uniform_denom(denom)) {
220 ret = printf("%.*s",
221 (int)n->len - 1, n->cp);
222 if (ret < 0)
223 err(1, "printf");
224 }
225 if (unique) {
226 if (n == rand_root)
227 rand_root = n->next;
228 if (n == rand_tail)
229 rand_tail = prev;
230
231 prev->next = n->next;
232 rand_node_free(n);
233 numnode--;
234 }
235 break;
236 }
237 }
238 }
239
240 fflush(stdout);
241
242 if (!unique)
243 rand_node_free_rec(rand_root);
244
245 return(0);
246 }
247