1 /* $NetBSD: rand-timer.c,v 1.1.1.1 2011/04/13 18:14:50 elric Exp $ */ 2 3 /* 4 * Copyright (c) 1995, 1996, 1997, 1999, 2007 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 42 #include <krb5/roken.h> 43 44 #include "randi.h" 45 46 #ifndef WIN32 /* don't bother with this on windows */ 47 48 static volatile int counter; 49 static volatile unsigned char *gdata; /* Global data */ 50 static volatile int igdata; /* Index into global data */ 51 static int gsize; 52 53 static 54 RETSIGTYPE 55 sigALRM(int sig) 56 { 57 if (igdata < gsize) 58 gdata[igdata++] ^= counter & 0xff; 59 60 #ifndef HAVE_SIGACTION 61 signal(SIGALRM, sigALRM); /* Reinstall SysV signal handler */ 62 #endif 63 SIGRETURN(0); 64 } 65 66 #ifndef HAVE_SETITIMER 67 static void 68 pacemaker(struct timeval *tv) 69 { 70 fd_set fds; 71 pid_t pid; 72 pid = getppid(); 73 while(1){ 74 FD_ZERO(&fds); 75 FD_SET(0, &fds); 76 select(1, &fds, NULL, NULL, tv); 77 kill(pid, SIGALRM); 78 } 79 } 80 #endif 81 82 #ifdef HAVE_SIGACTION 83 /* XXX ugly hack, should perhaps use function from roken */ 84 static RETSIGTYPE 85 (*fake_signal(int sig, RETSIGTYPE (*f)(int)))(int) 86 { 87 struct sigaction sa, osa; 88 sa.sa_handler = f; 89 sa.sa_flags = 0; 90 sigemptyset(&sa.sa_mask); 91 sigaction(sig, &sa, &osa); 92 return osa.sa_handler; 93 } 94 #define signal(S, F) fake_signal((S), (F)) 95 #endif 96 97 #endif /* WIN32*/ 98 99 /* 100 * 101 */ 102 103 static void 104 timer_seed(const void *indata, int size) 105 { 106 } 107 108 static int 109 timer_bytes(unsigned char *outdata, int size) 110 { 111 #ifdef WIN32 112 return 0; 113 #else /* WIN32 */ 114 struct itimerval tv, otv; 115 RETSIGTYPE (*osa)(int); 116 int i, j; 117 #ifndef HAVE_SETITIMER 118 RETSIGTYPE (*ochld)(int); 119 pid_t pid; 120 #endif 121 122 gdata = outdata; 123 gsize = size; 124 igdata = 0; 125 126 osa = signal(SIGALRM, sigALRM); 127 128 /* Start timer */ 129 tv.it_value.tv_sec = 0; 130 tv.it_value.tv_usec = 10 * 1000; /* 10 ms */ 131 tv.it_interval = tv.it_value; 132 #ifdef HAVE_SETITIMER 133 setitimer(ITIMER_REAL, &tv, &otv); 134 #else 135 ochld = signal(SIGCHLD, SIG_IGN); 136 pid = fork(); 137 if(pid == -1){ 138 signal(SIGCHLD, ochld != SIG_ERR ? ochld : SIG_DFL); 139 des_not_rand_data(data, size); 140 return; 141 } 142 if(pid == 0) 143 pacemaker(&tv.it_interval); 144 #endif 145 146 for(i = 0; i < 4; i++) { 147 for (igdata = 0; igdata < size;) /* igdata++ in sigALRM */ 148 counter++; 149 for (j = 0; j < size; j++) /* Only use 2 bits each lap */ 150 gdata[j] = (gdata[j]>>2) | (gdata[j]<<6); 151 } 152 #ifdef HAVE_SETITIMER 153 setitimer(ITIMER_REAL, &otv, 0); 154 #else 155 kill(pid, SIGKILL); 156 while(waitpid(pid, NULL, 0) != pid); 157 signal(SIGCHLD, ochld != SIG_ERR ? ochld : SIG_DFL); 158 #endif 159 signal(SIGALRM, osa != SIG_ERR ? osa : SIG_DFL); 160 161 return 1; 162 #endif 163 } 164 165 static void 166 timer_cleanup(void) 167 { 168 } 169 170 static void 171 timer_add(const void *indata, int size, double entropi) 172 { 173 } 174 175 static int 176 timer_pseudorand(unsigned char *outdata, int size) 177 { 178 return timer_bytes(outdata, size); 179 } 180 181 static int 182 timer_status(void) 183 { 184 #ifdef WIN32 185 return 0; 186 #else 187 return 1; 188 #endif 189 } 190 191 const RAND_METHOD hc_rand_timer_method = { 192 timer_seed, 193 timer_bytes, 194 timer_cleanup, 195 timer_add, 196 timer_pseudorand, 197 timer_status 198 }; 199 200 const RAND_METHOD * 201 RAND_timer_method(void) 202 { 203 return &hc_rand_timer_method; 204 } 205