crypto/dist/heimdal/lib/hcrypto/rand-unix.c

   1 /*
   2  * Copyright (c) 2006 Kungliga Tekniska Högskolan
   3  * (Royal Institute of Technology, Stockholm, Sweden).
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  *
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  *
  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  *
  17  * 3. Neither the name of the Institute nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #ifdef HAVE_CONFIG_H
  35 #include <config.h>
  36 #endif
  37
  38 __RCSID("$Heimdal: rand-unix.c 20028 2007-01-21 09:54:56Z lha $"
  39         "$NetBSD$");
  40
  41 #include <stdio.h>
  42 #include <stdlib.h>
  43 #include <rand.h>
  44
  45 #include <roken.h>
  46
  47 #include "randi.h"
  48
  49 /*
  50  * Unix /dev/random
  51  */
  52
  53 static int
  54 get_device_fd(int flags)
  55 {
  56     static const char *rnd_devices[] = {
  57         "/dev/urandom",
  58         "/dev/random",
  59         "/dev/srandom",
  60         "/dev/arandom",
  61         NULL
  62     };
  63     const char **p;
  64
  65     for(p = rnd_devices; *p; p++) {
  66         int fd = open(*p, flags | O_NDELAY);
  67         if(fd >= 0)
  68             return fd;
  69     }
  70     return -1;
  71 }
  72
  73 static void
  74 unix_seed(const void *indata, int size)
  75 {
  76     int fd;
  77
  78     if (size <= 0)
  79         return;
  80
  81     fd = get_device_fd(O_WRONLY);
  82     if (fd < 0)
  83         return;
  84
  85     write(fd, indata, size);
  86     close(fd);
  87
  88 }
  89
  90 static int
  91 unix_bytes(unsigned char *outdata, int size)
  92 {
  93     ssize_t count;
  94     int fd;
  95
  96     if (size <= 0)
  97         return 0;
  98
  99     fd = get_device_fd(O_RDONLY);
 100     if (fd < 0)
 101         return 0;
 102
 103     while (size > 0) {
 104         count = read (fd, outdata, size);
 105         if (count < 0 && errno == EINTR)
 106             continue;
 107         else if (count <= 0) {
 108             close(fd);
 109             return 0;
 110         }
 111         outdata += count;
 112         size -= count;
 113     }
 114     close(fd);
 115
 116     return 1;
 117 }
 118
 119 static void
 120 unix_cleanup(void)
 121 {
 122 }
 123
 124 static void
 125 unix_add(const void *indata, int size, double entropi)
 126 {
 127     unix_seed(indata, size);
 128 }
 129
 130 static int
 131 unix_pseudorand(unsigned char *outdata, int size)
 132 {
 133     return unix_bytes(outdata, size);
 134 }
 135
 136 static int
 137 unix_status(void)
 138 {
 139     int fd;
 140
 141     fd = get_device_fd(O_RDONLY);
 142     if (fd < 0)
 143         return 0;
 144     close(fd);
 145
 146     return 1;
 147 }
 148
 149 const RAND_METHOD hc_rand_unix_method = {
 150     unix_seed,
 151     unix_bytes,
 152     unix_cleanup,
 153     unix_add,
 154     unix_pseudorand,
 155     unix_status
 156 };
 157
 158 const RAND_METHOD *
 159 RAND_unix_method(void)
 160 {
 161     return &hc_rand_unix_method;
 162 }