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
sigALRM(int sig)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
pacemaker(struct timeval * tv)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
fake_signal(int sig,RETSIGTYPE (* f)(int))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
timer_seed(const void * indata,int size)104 timer_seed(const void *indata, int size)
105 {
106 }
107
108 static int
timer_bytes(unsigned char * outdata,int size)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
timer_cleanup(void)166 timer_cleanup(void)
167 {
168 }
169
170 static void
timer_add(const void * indata,int size,double entropi)171 timer_add(const void *indata, int size, double entropi)
172 {
173 }
174
175 static int
timer_pseudorand(unsigned char * outdata,int size)176 timer_pseudorand(unsigned char *outdata, int size)
177 {
178 return timer_bytes(outdata, size);
179 }
180
181 static int
timer_status(void)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 *
RAND_timer_method(void)201 RAND_timer_method(void)
202 {
203 return &hc_rand_timer_method;
204 }
205