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 <stdbool.h>
  37 #include <stdlib.h>
  38 #include <stdint.h>
  39 #include <stdio.h>
  40 #include <string.h>
  41 #include <unistd.h>
  42
  43 #include "randomize_fd.h"
  44
  45 static struct rand_node *rand_root;
  46 static struct rand_node *rand_tail;
  47
  48 static struct rand_node *
  49 rand_node_allocate(void)
  50 {
  51         struct rand_node *n;
  52
  53         n = (struct rand_node *)malloc(sizeof(struct rand_node));
  54         if (n == NULL)
  55                 err(1, "malloc");
  56
  57         n->len = 0;
  58         n->cp = NULL;
  59         n->next = NULL;
  60         return(n);
  61 }
  62
  63 static void
  64 rand_node_free(struct rand_node *n)
  65 {
  66         if (n != NULL) {
  67                 if (n->cp != NULL)
  68                         free(n->cp);
  69
  70                 free(n);
  71         }
  72 }
  73
  74 static void
  75 rand_node_free_rec(struct rand_node *n)
  76 {
  77         if (n != NULL) {
  78                 if (n->next != NULL)
  79                         rand_node_free_rec(n->next);
  80
  81                 rand_node_free(n);
  82         }
  83 }
  84
  85 static void
  86 rand_node_append(struct rand_node *n)
  87 {
  88         if (rand_root == NULL)
  89                 rand_root = rand_tail = n;
  90         else {
  91                 rand_tail->next = n;
  92                 rand_tail = n;
  93         }
  94 }
  95
  96 int
  97 randomize_fd(int fd, int type, int unique, double denom)
  98 {
  99         u_char *buf;
 100         u_int slen;
 101         u_long i, j, numnode, selected;
 102         struct rand_node *n, *prev;
 103         int bufleft, eof, fndstr, ret;
 104         size_t bufc, buflen;
 105         ssize_t len;
 106
 107         rand_root = rand_tail = NULL;
 108         bufc = i = 0;
 109         bufleft = eof = fndstr = numnode = 0;
 110
 111         if (type == RANDOM_TYPE_UNSET)
 112                 type = RANDOM_TYPE_LINES;
 113
 114         buflen = sizeof(u_char) * MAXBSIZE;
 115         buf = (u_char *)malloc(buflen);
 116         if (buf == NULL)
 117                 err(1, "malloc");
 118
 119         while (!eof) {
 120                 /* Check to see if we have bits in the buffer */
 121                 if (bufleft == 0) {
 122                         len = read(fd, buf, buflen);
 123                         if (len == -1)
 124                                 err(1, "read");
 125                         else if (len == 0) {
 126                                 eof++;
 127                                 break;
 128                         } else if ((size_t)len < buflen)
 129                                 buflen = (size_t)len;
 130
 131                         bufleft = (int)len;
 132                 }
 133
 134                 /* Look for a newline */
 135                 for (i = bufc; i <= buflen && bufleft >= 0; i++, bufleft--) {
 136                         if (i == buflen) {
 137                                 if (fndstr) {
 138                                         if (!eof) {
 139                                                 memmove(buf, &buf[bufc], i - bufc);
 140                                                 i -= bufc;
 141                                                 bufc = 0;
 142                                                 len = read(fd, &buf[i], buflen - i);
 143                                                 if (len == -1)
 144                                                         err(1, "read");
 145                                                 else if (len == 0) {
 146                                                         eof++;
 147                                                         break;
 148                                                 } else if (len < (ssize_t)(buflen - i))
 149                                                         buflen = i + (size_t)len;
 150
 151                                                 bufleft = (int)len;
 152                                                 fndstr = 0;
 153                                         }
 154                                 } else {
 155                                         buflen *= 2;
 156                                         buf = (u_char *)realloc(buf, buflen);
 157                                         if (buf == NULL)
 158                                                 err(1, "realloc");
 159
 160                                         if (!eof) {
 161                                                 len = read(fd, &buf[i], buflen - i);
 162                                                 if (len == -1)
 163                                                         err(1, "read");
 164                                                 else if (len == 0) {
 165                                                         eof++;
 166                                                         break;
 167                                                 } else if (len < (ssize_t)(buflen - i))
 168                                                         buflen = i + (size_t)len;
 169
 170                                                 bufleft = (int)len;
 171                                         }
 172
 173                                 }
 174                         }
 175
 176                         if ((type == RANDOM_TYPE_LINES && buf[i] == '\n') ||
 177                             (type == RANDOM_TYPE_WORDS && isspace(buf[i])) ||
 178                             (eof && i == buflen - 1)) {
 179 make_token:
 180                                 if (numnode == UINT32_MAX - 1) {
 181                                         errno = EFBIG;
 182                                         err(1, "too many delimiters");
 183                                 }
 184                                 numnode++;
 185                                 n = rand_node_allocate();
 186                                 if (-1 != (int)i) {
 187                                         slen = i - (u_long)bufc;
 188                                         n->len = slen + 2;
 189                                         n->cp = (u_char *)malloc(slen + 2);
 190                                         if (n->cp == NULL)
 191                                                 err(1, "malloc");
 192
 193                                         memmove(n->cp, &buf[bufc], slen);
 194                                         n->cp[slen] = buf[i];
 195                                         n->cp[slen + 1] = '\0';
 196                                         bufc = i + 1;
 197                                 }
 198                                 rand_node_append(n);
 199                                 fndstr = 1;
 200                         }
 201                 }
 202         }
 203
 204         /* Necessary evil to compensate for files that don't end with a newline */
 205         if (bufc != i) {
 206                 i--;
 207                 goto make_token;
 208         }
 209
 210         (void)close(fd);
 211
 212         free(buf);
 213
 214         for (i = numnode; i > 0; i--) {
 215                 selected = arc4random_uniform(numnode);
 216
 217                 for (j = 0, prev = n = rand_root; n != NULL; j++, prev = n, n = n->next) {
 218                         if (j == selected) {
 219                                 if (n->cp == NULL)
 220                                         break;
 221
 222                                 if (random_uniform_denom(denom)) {
 223                                         ret = printf("%.*s",
 224                                                 (int)n->len - 1, n->cp);
 225                                         if (ret < 0)
 226                                                 err(1, "printf");
 227                                 }
 228                                 if (unique) {
 229                                         if (n == rand_root)
 230                                                 rand_root = n->next;
 231                                         if (n == rand_tail)
 232                                                 rand_tail = prev;
 233
 234                                         prev->next = n->next;
 235                                         rand_node_free(n);
 236                                         numnode--;
 237                                 }
 238                                 break;
 239                         }
 240                 }
 241         }
 242
 243         fflush(stdout);
 244
 245         if (!unique)
 246                 rand_node_free_rec(rand_root);
 247
 248         return(0);
 249 }