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/module.h> 42 #include <sys/mutex.h> 43 #include <sys/poll.h> 44 #include <sys/proc.h> 45 #include <sys/selinfo.h> 46 #include <sys/uio.h> 47 #include <sys/unistd.h> 48 #include <sys/vnode.h> 49 50 #include <machine/bus.h> 51 #include <machine/cpu.h> 52 53 #include <dev/random/randomdev.h> 54 55 #define RANDOM_MINOR 0 56 57 static d_close_t random_close; 58 static d_read_t random_read; 59 static d_write_t random_write; 60 static d_ioctl_t random_ioctl; 61 static d_poll_t random_poll; 62 63 static struct cdevsw random_cdevsw = { 64 .d_version = D_VERSION, 65 .d_flags = D_NEEDGIANT, 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 struct random_systat random_systat; 75 76 /* For use with make_dev(9)/destroy_dev(9). */ 77 static struct cdev *random_dev; 78 79 /* Used to fake out unused random calls in random_systat */ 80 void 81 random_null_func(void) 82 { 83 } 84 85 /* ARGSUSED */ 86 static int 87 random_close(struct cdev *dev __unused, int flags, int fmt __unused, 88 struct thread *td) 89 { 90 if ((flags & FWRITE) && (suser(td) == 0) 91 && (securelevel_gt(td->td_ucred, 0) == 0)) { 92 (*random_systat.reseed)(); 93 random_systat.seeded = 1; 94 } 95 96 return (0); 97 } 98 99 /* ARGSUSED */ 100 static int 101 random_read(struct cdev *dev __unused, struct uio *uio, int flag) 102 { 103 int c, error = 0; 104 void *random_buf; 105 106 /* Blocking logic */ 107 while (!random_systat.seeded && !error) { 108 if (flag & IO_NDELAY) 109 error = EWOULDBLOCK; 110 else { 111 printf("Entropy device is blocking.\n"); 112 error = tsleep(&random_systat, 113 PUSER | PCATCH, "block", 0); 114 } 115 } 116 117 /* The actual read */ 118 if (!error) { 119 120 random_buf = (void *)malloc(PAGE_SIZE, M_TEMP, M_WAITOK); 121 122 while (uio->uio_resid > 0 && !error) { 123 c = MIN(uio->uio_resid, PAGE_SIZE); 124 c = (*random_systat.read)(random_buf, c); 125 error = uiomove(random_buf, c, uio); 126 } 127 128 free(random_buf, M_TEMP); 129 130 } 131 132 return (error); 133 } 134 135 /* ARGSUSED */ 136 static int 137 random_write(struct cdev *dev __unused, struct uio *uio, int flag __unused) 138 { 139 int c, error = 0; 140 void *random_buf; 141 142 random_buf = (void *)malloc(PAGE_SIZE, M_TEMP, M_WAITOK); 143 144 while (uio->uio_resid > 0) { 145 c = MIN((int)uio->uio_resid, PAGE_SIZE); 146 error = uiomove(random_buf, c, uio); 147 if (error) 148 break; 149 (*random_systat.write)(random_buf, c); 150 } 151 152 free(random_buf, M_TEMP); 153 154 return (error); 155 } 156 157 /* ARGSUSED */ 158 static int 159 random_ioctl(struct cdev *dev __unused, u_long cmd, caddr_t addr __unused, 160 int flags __unused, struct thread *td __unused) 161 { 162 int error = 0; 163 164 switch (cmd) { 165 /* Really handled in upper layer */ 166 case FIOASYNC: 167 case FIONBIO: 168 break; 169 default: 170 error = ENOTTY; 171 } 172 return (error); 173 } 174 175 /* ARGSUSED */ 176 static int 177 random_poll(struct cdev *dev __unused, int events, struct thread *td) 178 { 179 int revents = 0; 180 181 if (events & (POLLIN | POLLRDNORM)) { 182 if (random_systat.seeded) 183 revents = events & (POLLIN | POLLRDNORM); 184 else 185 selrecord(td, &random_systat.rsel); 186 } 187 return (revents); 188 } 189 190 /* ARGSUSED */ 191 static int 192 random_modevent(module_t mod __unused, int type, void *data __unused) 193 { 194 int error = 0; 195 196 switch (type) { 197 case MOD_LOAD: 198 random_ident_hardware(&random_systat); 199 (*random_systat.init)(); 200 201 if (bootverbose) 202 printf("random: <entropy source, %s>\n", 203 random_systat.ident); 204 205 random_dev = make_dev(&random_cdevsw, RANDOM_MINOR, 206 UID_ROOT, GID_WHEEL, 0666, "random"); 207 make_dev_alias(random_dev, "urandom"); /* XXX Deprecated */ 208 209 break; 210 211 case MOD_UNLOAD: 212 (*random_systat.deinit)(); 213 214 destroy_dev(random_dev); 215 216 break; 217 218 case MOD_SHUTDOWN: 219 break; 220 221 default: 222 error = EOPNOTSUPP; 223 break; 224 225 } 226 return (error); 227 } 228 229 DEV_MODULE(random, random_modevent, NULL); 230