usr.bin/random/randomize_fd.c

   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/cdefs.h>
  28 __FBSDID("$FreeBSD$");
  29
  30 #include <sys/types.h>
  31 #include <sys/param.h>
  32
  33 #include <ctype.h>
  34 #include <err.h>
  35 #include <errno.h>
  36 #include <stdlib.h>
  37 #include <stdint.h>
  38 #include <stdio.h>
  39 #include <string.h>
  40 #include <unistd.h>
  41
  42 #include "randomize_fd.h"
  43
  44 static struct rand_node *rand_root;
  45 static struct rand_node *rand_tail;
  46
  47 static struct rand_node *
  48 rand_node_allocate(void)
  49 {
  50         struct rand_node *n;
  51
  52         n = (struct rand_node *)malloc(sizeof(struct rand_node));
  53         if (n == NULL)
  54                 err(1, "malloc");
  55
  56         n->len = 0;
  57         n->cp = NULL;
  58         n->next = NULL;
  59         return(n);
  60 }
  61
  62 static void
  63 rand_node_free(struct rand_node *n)
  64 {
  65         if (n != NULL) {
  66                 if (n->cp != NULL)
  67                         free(n->cp);
  68
  69                 free(n);
  70         }
  71 }
  72
  73 static void
  74 rand_node_free_rec(struct rand_node *n)
  75 {
  76         if (n != NULL) {
  77                 if (n->next != NULL)
  78                         rand_node_free_rec(n->next);
  79
  80                 rand_node_free(n);
  81         }
  82 }
  83
  84 static void
  85 rand_node_append(struct rand_node *n)
  86 {
  87         if (rand_root == NULL)
  88                 rand_root = rand_tail = n;
  89         else {
  90                 rand_tail->next = n;
  91                 rand_tail = n;
  92         }
  93 }
  94
  95 int
  96 randomize_fd(int fd, int type, int unique, double denom)
  97 {
  98         u_char *buf;
  99         u_int slen;
 100         u_long i, j, numnode, selected;
 101         struct rand_node *n, *prev;
 102         int bufleft, eof, fndstr, ret;
 103         size_t bufc, buflen;
 104         ssize_t len;
 105
 106         rand_root = rand_tail = NULL;
 107         bufc = i = 0;
 108         bufleft = eof = fndstr = numnode = 0;
 109
 110         if (type == RANDOM_TYPE_UNSET)
 111                 type = RANDOM_TYPE_LINES;
 112
 113         buflen = sizeof(u_char) * MAXBSIZE;
 114         buf = (u_char *)malloc(buflen);
 115         if (buf == NULL)
 116                 err(1, "malloc");
 117
 118         while (!eof) {
 119                 /* Check to see if we have bits in the buffer */
 120                 if (bufleft == 0) {
 121                         len = read(fd, buf, buflen);
 122                         if (len == -1)
 123                                 err(1, "read");
 124                         else if (len == 0) {
 125                                 eof++;
 126                                 break;
 127                         } else if ((size_t)len < buflen)
 128                                 buflen = (size_t)len;
 129
 130                         bufleft = (int)len;
 131                 }
 132
 133                 /* Look for a newline */
 134                 for (i = bufc; i <= buflen && bufleft >= 0; i++, bufleft--) {
 135                         if (i == buflen) {
 136                                 if (fndstr) {
 137                                         if (!eof) {
 138                                                 memmove(buf, &buf[bufc], i - bufc);
 139                                                 i -= bufc;
 140                                                 bufc = 0;
 141                                                 len = read(fd, &buf[i], buflen - i);
 142                                                 if (len == -1)
 143                                                         err(1, "read");
 144                                                 else if (len == 0) {
 145                                                         eof++;
 146                                                         break;
 147                                                 } else if (len < (ssize_t)(buflen - i))
 148                                                         buflen = i + (size_t)len;
 149
 150                                                 bufleft = (int)len;
 151                                                 fndstr = 0;
 152                                         }
 153                                 } else {
 154                                         buflen *= 2;
 155                                         buf = (u_char *)realloc(buf, buflen);
 156                                         if (buf == NULL)
 157                                                 err(1, "realloc");
 158
 159                                         if (!eof) {
 160                                                 len = read(fd, &buf[i], buflen - i);
 161                                                 if (len == -1)
 162                                                         err(1, "read");
 163                                                 else if (len == 0) {
 164                                                         eof++;
 165                                                         break;
 166                                                 } else if (len < (ssize_t)(buflen - i))
 167                                                         buflen = i + (size_t)len;
 168
 169                                                 bufleft = (int)len;
 170                                         }
 171
 172                                 }
 173                         }
 174
 175                         if ((type == RANDOM_TYPE_LINES && buf[i] == '\n') ||
 176                             (type == RANDOM_TYPE_WORDS && isspace(buf[i])) ||
 177                             (eof && i == buflen - 1)) {
 178 make_token:
 179                                 if (numnode == UINT32_MAX - 1) {
 180                                         errno = EFBIG;
 181                                         err(1, "too many delimiters");
 182                                 }
 183                                 numnode++;
 184                                 n = rand_node_allocate();
 185                                 if (-1 != (int)i) {
 186                                         slen = i - (u_long)bufc;
 187                                         n->len = slen + 2;
 188                                         n->cp = (u_char *)malloc(slen + 2);
 189                                         if (n->cp == NULL)
 190                                                 err(1, "malloc");
 191
 192                                         memmove(n->cp, &buf[bufc], slen);
 193                                         n->cp[slen] = buf[i];
 194                                         n->cp[slen + 1] = '\0';
 195                                         bufc = i + 1;
 196                                 }
 197                                 rand_node_append(n);
 198                                 fndstr = 1;
 199                         }
 200                 }
 201         }
 202
 203         /* Necessary evil to compensate for files that don't end with a newline */
 204         if (bufc != i) {
 205                 i--;
 206                 goto make_token;
 207         }
 208
 209         (void)close(fd);
 210
 211         free(buf);
 212
 213         for (i = numnode; i > 0; i--) {
 214                 selected = arc4random_uniform(numnode);
 215
 216                 for (j = 0, prev = n = rand_root; n != NULL; j++, prev = n, n = n->next) {
 217                         if (j == selected) {
 218                                 if (n->cp == NULL)
 219                                         break;
 220
 221                                 if (arc4random_uniform(denom) == 0) {
 222                                         ret = printf("%.*s",
 223                                                 (int)n->len - 1, n->cp);
 224                                         if (ret < 0)
 225                                                 err(1, "printf");
 226                                 }
 227                                 if (unique) {
 228                                         if (n == rand_root)
 229                                                 rand_root = n->next;
 230                                         if (n == rand_tail)
 231                                                 rand_tail = prev;
 232
 233                                         prev->next = n->next;
 234                                         rand_node_free(n);
 235                                         numnode--;
 236                                 }
 237                                 break;
 238                         }
 239                 }
 240         }
 241
 242         fflush(stdout);
 243
 244         if (!unique)
 245                 rand_node_free_rec(rand_root);
 246
 247         return(0);
 248 }