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 } 168