lib/hcrypto/rand-timer.c

   1 /*
   2  * Copyright (c) 1995, 1996, 1997, 1999, 2007 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 #include <config.h>
  35
  36 #include <stdio.h>
  37 #include <stdlib.h>
  38 #include <rand.h>
  39
  40 #include <roken.h>
  41
  42 #include "randi.h"
  43
  44 #ifndef WIN32 /* don't bother with this on windows */
  45
  46 static volatile int counter;
  47 static volatile unsigned char *gdata; /* Global data */
  48 static volatile int igdata;     /* Index into global data */
  49 static int gsize;
  50
  51 static
  52 RETSIGTYPE
  53 sigALRM(int sig)
  54 {
  55     if (igdata < gsize)
  56         gdata[igdata++] ^= counter & 0xff;
  57
  58 #ifndef HAVE_SIGACTION
  59     signal(SIGALRM, sigALRM); /* Reinstall SysV signal handler */
  60 #endif
  61     SIGRETURN(0);
  62 }
  63
  64 #ifndef HAVE_SETITIMER
  65 static void
  66 pacemaker(struct timeval *tv)
  67 {
  68     fd_set fds;
  69     pid_t pid;
  70     pid = getppid();
  71     while(1){
  72         FD_ZERO(&fds);
  73         FD_SET(0, &fds);
  74         select(1, &fds, NULL, NULL, tv);
  75         kill(pid, SIGALRM);
  76     }
  77 }
  78 #endif
  79
  80 #ifdef HAVE_SIGACTION
  81 /* XXX ugly hack, should perhaps use function from roken */
  82 static RETSIGTYPE
  83 (*fake_signal(int sig, RETSIGTYPE (*f)(int)))(int)
  84 {
  85     struct sigaction sa, osa;
  86     sa.sa_handler = f;
  87     sa.sa_flags = 0;
  88     sigemptyset(&sa.sa_mask);
  89     sigaction(sig, &sa, &osa);
  90     return osa.sa_handler;
  91 }
  92 #define signal(S, F) fake_signal((S), (F))
  93 #endif
  94
  95 #endif /* WIN32*/
  96
  97 /*
  98  *
  99  */
 100
 101 static void
 102 timer_seed(const void *indata, int size)
 103 {
 104 }
 105
 106 static int
 107 timer_bytes(unsigned char *outdata, int size)
 108 {
 109 #ifdef WIN32
 110     return 0;
 111 #else /* WIN32 */
 112     struct itimerval tv, otv;
 113     RETSIGTYPE (*osa)(int);
 114     int i, j;
 115 #ifndef HAVE_SETITIMER
 116     RETSIGTYPE (*ochld)(int);
 117     pid_t pid;
 118 #endif
 119
 120     gdata = outdata;
 121     gsize = size;
 122     igdata = 0;
 123
 124     osa = signal(SIGALRM, sigALRM);
 125
 126     /* Start timer */
 127     tv.it_value.tv_sec = 0;
 128     tv.it_value.tv_usec = 10 * 1000; /* 10 ms */
 129     tv.it_interval = tv.it_value;
 130 #ifdef HAVE_SETITIMER
 131     setitimer(ITIMER_REAL, &tv, &otv);
 132 #else
 133     ochld = signal(SIGCHLD, SIG_IGN);
 134     pid = fork();
 135     if(pid == -1){
 136         signal(SIGCHLD, ochld != SIG_ERR ? ochld : SIG_DFL);
 137         des_not_rand_data(data, size);
 138         return;
 139     }
 140     if(pid == 0)
 141         pacemaker(&tv.it_interval);
 142 #endif
 143
 144     for(i = 0; i < 4; i++) {
 145         for (igdata = 0; igdata < size;) /* igdata++ in sigALRM */
 146             counter++;
 147         for (j = 0; j < size; j++) /* Only use 2 bits each lap */
 148             gdata[j] = (gdata[j]>>2) | (gdata[j]<<6);
 149     }
 150 #ifdef HAVE_SETITIMER
 151     setitimer(ITIMER_REAL, &otv, 0);
 152 #else
 153     kill(pid, SIGKILL);
 154     while(waitpid(pid, NULL, 0) != pid);
 155     signal(SIGCHLD, ochld != SIG_ERR ? ochld : SIG_DFL);
 156 #endif
 157     signal(SIGALRM, osa != SIG_ERR ? osa : SIG_DFL);
 158
 159     return 1;
 160 #endif
 161 }
 162
 163 static void
 164 timer_cleanup(void)
 165 {
 166 }
 167
 168 static void
 169 timer_add(const void *indata, int size, double entropi)
 170 {
 171 }
 172
 173 static int
 174 timer_pseudorand(unsigned char *outdata, int size)
 175 {
 176     return timer_bytes(outdata, size);
 177 }
 178
 179 static int
 180 timer_status(void)
 181 {
 182 #ifdef WIN32
 183     return 0;
 184 #else
 185     return 1;
 186 #endif
 187 }
 188
 189 const RAND_METHOD hc_rand_timer_method = {
 190     timer_seed,
 191     timer_bytes,
 192     timer_cleanup,
 193     timer_add,
 194     timer_pseudorand,
 195     timer_status
 196 };
 197
 198 const RAND_METHOD *
 199 RAND_timer_method(void)
 200 {
 201     return &hc_rand_timer_method;
 202 }