1 /*- 2 * Copyright (c) 2013 Arthur Mesh <arthurmesh@gmail.com> 3 * Copyright (c) 2000-2004 Mark R V Murray 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 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer 11 * in this position and unchanged. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 * 27 */ 28 29 #include <sys/cdefs.h> 30 __FBSDID("$FreeBSD$"); 31 32 #include <sys/param.h> 33 #include <sys/systm.h> 34 #include <sys/bus.h> 35 #include <sys/conf.h> 36 #include <sys/fcntl.h> 37 #include <sys/filio.h> 38 #include <sys/kernel.h> 39 #include <sys/kthread.h> 40 #include <sys/lock.h> 41 #include <sys/malloc.h> 42 #include <sys/module.h> 43 #include <sys/mutex.h> 44 #include <sys/poll.h> 45 #include <sys/priv.h> 46 #include <sys/proc.h> 47 #include <sys/selinfo.h> 48 #include <sys/uio.h> 49 #include <sys/unistd.h> 50 51 #include <machine/bus.h> 52 #include <machine/cpu.h> 53 54 #include <dev/random/randomdev.h> 55 56 #define RANDOM_MINOR 0 57 58 static d_close_t random_close; 59 static d_read_t random_read; 60 static d_write_t random_write; 61 static d_ioctl_t random_ioctl; 62 static d_poll_t random_poll; 63 64 static struct cdevsw random_cdevsw = { 65 .d_version = D_VERSION, 66 .d_close = random_close, 67 .d_read = random_read, 68 .d_write = random_write, 69 .d_ioctl = random_ioctl, 70 .d_poll = random_poll, 71 .d_name = "random", 72 }; 73 74 static struct random_adaptor *random_adaptor; 75 static eventhandler_tag attach_tag; 76 static int random_inited; 77 78 79 /* For use with make_dev(9)/destroy_dev(9). */ 80 static struct cdev *random_dev; 81 82 /* Used to fake out unused random calls in random_adaptor */ 83 void 84 random_null_func(void) 85 { 86 } 87 88 /* ARGSUSED */ 89 static int 90 random_close(struct cdev *dev __unused, int flags, int fmt __unused, 91 struct thread *td) 92 { 93 if ((flags & FWRITE) && (priv_check(td, PRIV_RANDOM_RESEED) == 0) 94 && (securelevel_gt(td->td_ucred, 0) == 0)) { 95 (*random_adaptor->reseed)(); 96 random_adaptor->seeded = 1; 97 arc4rand(NULL, 0, 1); /* Reseed arc4random as well. */ 98 } 99 100 return (0); 101 } 102 103 /* ARGSUSED */ 104 static int 105 random_read(struct cdev *dev __unused, struct uio *uio, int flag) 106 { 107 int c, error = 0; 108 void *random_buf; 109 110 /* Blocking logic */ 111 if (!random_adaptor->seeded) 112 error = (*random_adaptor->block)(flag); 113 114 /* The actual read */ 115 if (!error) { 116 117 random_buf = (void *)malloc(PAGE_SIZE, M_TEMP, M_WAITOK); 118 119 while (uio->uio_resid > 0 && !error) { 120 c = MIN(uio->uio_resid, PAGE_SIZE); 121 c = (*random_adaptor->read)(random_buf, c); 122 error = uiomove(random_buf, c, uio); 123 } 124 125 free(random_buf, M_TEMP); 126 127 } 128 129 return (error); 130 } 131 132 /* ARGSUSED */ 133 static int 134 random_write(struct cdev *dev __unused, struct uio *uio, int flag __unused) 135 { 136 int c, error = 0; 137 void *random_buf; 138 139 random_buf = (void *)malloc(PAGE_SIZE, M_TEMP, M_WAITOK); 140 141 while (uio->uio_resid > 0) { 142 c = MIN((int)uio->uio_resid, PAGE_SIZE); 143 error = uiomove(random_buf, c, uio); 144 if (error) 145 break; 146 (*random_adaptor->write)(random_buf, c); 147 } 148 149 free(random_buf, M_TEMP); 150 151 return (error); 152 } 153 154 /* ARGSUSED */ 155 static int 156 random_ioctl(struct cdev *dev __unused, u_long cmd, caddr_t addr __unused, 157 int flags __unused, struct thread *td __unused) 158 { 159 int error = 0; 160 161 switch (cmd) { 162 /* Really handled in upper layer */ 163 case FIOASYNC: 164 case FIONBIO: 165 break; 166 default: 167 error = ENOTTY; 168 } 169 return (error); 170 } 171 172 /* ARGSUSED */ 173 static int 174 random_poll(struct cdev *dev __unused, int events, struct thread *td) 175 { 176 int revents = 0; 177 178 if (events & (POLLIN | POLLRDNORM)) { 179 if (random_adaptor->seeded) 180 revents = events & (POLLIN | POLLRDNORM); 181 else 182 revents = (*random_adaptor->poll) (events,td); 183 } 184 return (revents); 185 } 186 187 static void 188 random_initialize(void *p, struct random_adaptor *s) 189 { 190 if (random_inited) { 191 printf("random: <%s> already initialized\n", 192 random_adaptor->ident); 193 return; 194 } 195 196 random_adaptor = s; 197 198 (s->init)(); 199 200 printf("random: <%s> initialized\n", s->ident); 201 202 random_dev = make_dev_credf(MAKEDEV_ETERNAL_KLD, &random_cdevsw, 203 RANDOM_MINOR, NULL, UID_ROOT, GID_WHEEL, 0666, "random"); 204 make_dev_alias(random_dev, "urandom"); /* XXX Deprecated */ 205 206 /* mark random(4) as initialized, to avoid being called again */ 207 random_inited = 1; 208 } 209 210 /* ARGSUSED */ 211 static int 212 random_modevent(module_t mod __unused, int type, void *data __unused) 213 { 214 int error = 0; 215 216 switch (type) { 217 case MOD_LOAD: 218 random_ident_hardware(&random_adaptor); 219 220 if (random_adaptor == NULL) { 221 printf( 222 "random: No random adaptor attached, postponing initialization\n"); 223 attach_tag = EVENTHANDLER_REGISTER(random_adaptor_attach, 224 random_initialize, NULL, EVENTHANDLER_PRI_ANY); 225 } else { 226 random_initialize(NULL, random_adaptor); 227 } 228 229 break; 230 231 case MOD_UNLOAD: 232 if (random_adaptor != NULL) { 233 (*random_adaptor->deinit)(); 234 destroy_dev(random_dev); 235 } 236 /* Unregister the event handler */ 237 if (attach_tag != NULL) { 238 EVENTHANDLER_DEREGISTER(random_adaptor_attach, 239 attach_tag); 240 } 241 242 break; 243 244 case MOD_SHUTDOWN: 245 break; 246 247 default: 248 error = EOPNOTSUPP; 249 break; 250 251 } 252 return (error); 253 } 254 255 DEV_MODULE(random, random_modevent, NULL); 256 MODULE_VERSION(random, 1); 257