1 /*- 2 * Copyright (c) 2000-2004 Mark R V Murray 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer 10 * in this position and unchanged. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 * 26 */ 27 28 #include <sys/cdefs.h> 29 __FBSDID("$FreeBSD$"); 30 31 #include <sys/param.h> 32 #include <sys/systm.h> 33 #include <sys/bus.h> 34 #include <sys/conf.h> 35 #include <sys/fcntl.h> 36 #include <sys/filio.h> 37 #include <sys/kernel.h> 38 #include <sys/kthread.h> 39 #include <sys/lock.h> 40 #include <sys/malloc.h> 41 #include <sys/mutex.h> 42 #include <sys/poll.h> 43 #include <sys/proc.h> 44 #include <sys/selinfo.h> 45 #include <sys/uio.h> 46 #include <sys/unistd.h> 47 #include <sys/vnode.h> 48 49 #include <machine/bus.h> 50 #include <machine/cpu.h> 51 52 #include <dev/random/randomdev.h> 53 54 #define RANDOM_MINOR 0 55 56 static d_close_t random_close; 57 static d_read_t random_read; 58 static d_write_t random_write; 59 static d_ioctl_t random_ioctl; 60 static d_poll_t random_poll; 61 62 static struct cdevsw random_cdevsw = { 63 .d_version = D_VERSION, 64 .d_flags = D_NEEDGIANT, 65 .d_close = random_close, 66 .d_read = random_read, 67 .d_write = random_write, 68 .d_ioctl = random_ioctl, 69 .d_poll = random_poll, 70 .d_name = "random", 71 }; 72 73 struct random_systat random_systat; 74 75 /* For use with make_dev(9)/destroy_dev(9). */ 76 static dev_t random_dev; 77 78 /* Used to fake out unused random calls in random_systat */ 79 void 80 random_null_func(void) 81 { 82 } 83 84 /* ARGSUSED */ 85 static int 86 random_close(dev_t dev __unused, int flags, int fmt __unused, 87 struct thread *td) 88 { 89 if ((flags & FWRITE) && (suser(td) == 0) 90 && (securelevel_gt(td->td_ucred, 0) == 0)) { 91 (*random_systat.reseed)(); 92 random_systat.seeded = 1; 93 } 94 95 return (0); 96 } 97 98 /* ARGSUSED */ 99 static int 100 random_read(dev_t dev __unused, struct uio *uio, int flag) 101 { 102 int c, error = 0; 103 void *random_buf; 104 105 /* Blocking logic */ 106 while (!random_systat.seeded && !error) { 107 if (flag & IO_NDELAY) 108 error = EWOULDBLOCK; 109 else { 110 /* No complaints please. This is temporary! */ 111 printf("Entropy device is blocking. " 112 "Dance fandango on keyboard to unblock.\n"); 113 error = tsleep(&random_systat, 114 PUSER | PCATCH, "block", 0); 115 } 116 } 117 118 /* The actual read */ 119 if (!error) { 120 121 random_buf = (void *)malloc(PAGE_SIZE, M_TEMP, M_WAITOK); 122 123 while (uio->uio_resid > 0 && !error) { 124 c = MIN(uio->uio_resid, PAGE_SIZE); 125 c = (*random_systat.read)(random_buf, c); 126 error = uiomove(random_buf, c, uio); 127 } 128 129 free(random_buf, M_TEMP); 130 131 } 132 133 return (error); 134 } 135 136 /* ARGSUSED */ 137 static int 138 random_write(dev_t dev __unused, struct uio *uio, int flag __unused) 139 { 140 int c, error = 0; 141 void *random_buf; 142 143 random_buf = (void *)malloc(PAGE_SIZE, M_TEMP, M_WAITOK); 144 145 while (uio->uio_resid > 0) { 146 c = MIN((int)uio->uio_resid, PAGE_SIZE); 147 error = uiomove(random_buf, c, uio); 148 if (error) 149 break; 150 (*random_systat.write)(random_buf, c); 151 } 152 153 free(random_buf, M_TEMP); 154 155 return (error); 156 } 157 158 /* ARGSUSED */ 159 static int 160 random_ioctl(dev_t dev __unused, u_long cmd, caddr_t addr __unused, 161 int flags __unused, struct thread *td __unused) 162 { 163 int error = 0; 164 165 switch (cmd) { 166 /* Really handled in upper layer */ 167 case FIOASYNC: 168 case FIONBIO: 169 break; 170 default: 171 error = ENOTTY; 172 } 173 return (error); 174 } 175 176 /* ARGSUSED */ 177 static int 178 random_poll(dev_t dev __unused, int events, struct thread *td) 179 { 180 int revents = 0; 181 182 if (events & (POLLIN | POLLRDNORM)) { 183 if (random_systat.seeded) 184 revents = events & (POLLIN | POLLRDNORM); 185 else 186 selrecord(td, &random_systat.rsel); 187 } 188 return (revents); 189 } 190 191 /* ARGSUSED */ 192 static int 193 random_modevent(module_t mod __unused, int type, void *data __unused) 194 { 195 int error = 0; 196 197 switch (type) { 198 case MOD_LOAD: 199 random_ident_hardware(&random_systat); 200 (*random_systat.init)(); 201 202 printf("random: <entropy source, %s>\n", random_systat.ident); 203 204 random_dev = make_dev(&random_cdevsw, RANDOM_MINOR, 205 UID_ROOT, GID_WHEEL, 0666, "random"); 206 make_dev_alias(random_dev, "urandom"); /* XXX Deprecated */ 207 208 break; 209 210 case MOD_UNLOAD: 211 (*random_systat.deinit)(); 212 213 destroy_dev(random_dev); 214 215 break; 216 217 case MOD_SHUTDOWN: 218 break; 219 220 } 221 return (error); 222 } 223 224 DEV_MODULE(random, random_modevent, NULL); 225