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

   1 /*      $NetBSD: rand-unix.c,v 1.1.1.1 2011/04/13 18:14:50 elric Exp $  */
   2
   3 /*
   4  * Copyright (c) 2006 Kungliga Tekniska Högskolan
   5  * (Royal Institute of Technology, Stockholm, Sweden).
   6  * All rights reserved.
   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  *
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  *
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  *
  19  * 3. Neither the name of the Institute nor the names of its contributors
  20  *    may be used to endorse or promote products derived from this software
  21  *    without specific prior written permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  33  * SUCH DAMAGE.
  34  */
  35
  36 #include <config.h>
  37
  38 #include <stdio.h>
  39 #include <stdlib.h>
  40 #include <rand.h>
  41 #include <heim_threads.h>
  42
  43 #include <krb5/roken.h>
  44
  45 #include "randi.h"
  46
  47 /*
  48  * Unix /dev/random
  49  */
  50
  51 int
  52 _hc_unix_device_fd(int flags, const char **fn)
  53 {
  54     static const char *rnd_devices[] = {
  55         "/dev/urandom",
  56         "/dev/random",
  57         "/dev/srandom",
  58         "/dev/arandom",
  59         NULL
  60     };
  61     const char **p;
  62
  63     for(p = rnd_devices; *p; p++) {
  64         int fd = open(*p, flags | O_NDELAY);
  65         if(fd >= 0) {
  66             if (fn)
  67                 *fn = *p;
  68             rk_cloexec(fd);
  69             return fd;
  70         }
  71     }
  72     return -1;
  73 }
  74
  75 static void
  76 unix_seed(const void *indata, int size)
  77 {
  78     int fd;
  79
  80     if (size <= 0)
  81         return;
  82
  83     fd = _hc_unix_device_fd(O_WRONLY, NULL);
  84     if (fd < 0)
  85         return;
  86
  87     write(fd, indata, size);
  88     close(fd);
  89
  90 }
  91
  92
  93 static int
  94 unix_bytes(unsigned char *outdata, int size)
  95 {
  96     ssize_t count;
  97     int fd;
  98
  99     if (size < 0)
 100         return 0;
 101     else if (size == 0)
 102         return 1;
 103
 104     fd = _hc_unix_device_fd(O_RDONLY, NULL);
 105     if (fd < 0)
 106         return 0;
 107
 108     while (size > 0) {
 109         count = read(fd, outdata, size);
 110         if (count < 0 && errno == EINTR)
 111             continue;
 112         else if (count <= 0) {
 113             close(fd);
 114             return 0;
 115         }
 116         outdata += count;
 117         size -= count;
 118     }
 119     close(fd);
 120
 121     return 1;
 122 }
 123
 124 static void
 125 unix_cleanup(void)
 126 {
 127 }
 128
 129 static void
 130 unix_add(const void *indata, int size, double entropi)
 131 {
 132     unix_seed(indata, size);
 133 }
 134
 135 static int
 136 unix_pseudorand(unsigned char *outdata, int size)
 137 {
 138     return unix_bytes(outdata, size);
 139 }
 140
 141 static int
 142 unix_status(void)
 143 {
 144     int fd;
 145
 146     fd = _hc_unix_device_fd(O_RDONLY, NULL);
 147     if (fd < 0)
 148         return 0;
 149     close(fd);
 150
 151     return 1;
 152 }
 153
 154 const RAND_METHOD hc_rand_unix_method = {
 155     unix_seed,
 156     unix_bytes,
 157     unix_cleanup,
 158     unix_add,
 159     unix_pseudorand,
 160     unix_status
 161 };
 162
 163 const RAND_METHOD *
 164 RAND_unix_method(void)
 165 {
 166     return &hc_rand_unix_method;
 167 }