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_close = random_close, 65 .d_read = random_read, 66 .d_write = random_write, 67 .d_ioctl = random_ioctl, 68 .d_poll = random_poll, 69 .d_name = "random", 70 }; 71 72 static void *random_buf; 73 74 struct random_systat random_systat; 75 76 /* For use with make_dev(9)/destroy_dev(9). */ 77 static dev_t 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(dev_t 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 mtx_lock(&random_systat.lock); 93 (*random_systat.reseed)(); 94 random_systat.seeded = 1; 95 mtx_unlock(&random_systat.lock); 96 } 97 return (0); 98 } 99 100 /* ARGSUSED */ 101 static int 102 random_read(dev_t dev __unused, struct uio *uio, int flag) 103 { 104 int c, error = 0; 105 106 /* Blocking logic */ 107 while (!random_systat.seeded && !error) { 108 if (flag & IO_NDELAY) 109 error = EWOULDBLOCK; 110 else 111 error = tsleep(&random_systat, 112 PUSER | PCATCH, "block", 0); 113 } 114 115 /* The actual read */ 116 if (!error) { 117 mtx_lock(&random_systat.lock); 118 while (uio->uio_resid > 0 && !error) { 119 c = MIN(uio->uio_resid, PAGE_SIZE); 120 c = (*random_systat.read)(random_buf, c); 121 error = uiomove(random_buf, c, uio); 122 } 123 mtx_unlock(&random_systat.lock); 124 } 125 return (error); 126 } 127 128 /* ARGSUSED */ 129 static int 130 random_write(dev_t dev __unused, struct uio *uio, int flag __unused) 131 { 132 int c, error = 0; 133 134 mtx_lock(&random_systat.lock); 135 while (uio->uio_resid > 0) { 136 c = MIN((int)uio->uio_resid, PAGE_SIZE); 137 error = uiomove(random_buf, c, uio); 138 if (error) 139 break; 140 (*random_systat.write)(random_buf, c); 141 } 142 mtx_unlock(&random_systat.lock); 143 return (error); 144 } 145 146 /* ARGSUSED */ 147 static int 148 random_ioctl(dev_t dev __unused, u_long cmd, caddr_t addr __unused, 149 int flags __unused, struct thread *td __unused) 150 { 151 int error = 0; 152 153 switch (cmd) { 154 /* Really handled in upper layer */ 155 case FIOASYNC: 156 case FIONBIO: 157 break; 158 default: 159 error = ENOTTY; 160 } 161 return (error); 162 } 163 164 /* ARGSUSED */ 165 static int 166 random_poll(dev_t dev __unused, int events, struct thread *td) 167 { 168 int revents = 0; 169 170 if (events & (POLLIN | POLLRDNORM)) { 171 if (random_systat.seeded) 172 revents = events & (POLLIN | POLLRDNORM); 173 else 174 selrecord(td, &random_systat.rsel); 175 } 176 return (revents); 177 } 178 179 /* ARGSUSED */ 180 static int 181 random_modevent(module_t mod __unused, int type, void *data __unused) 182 { 183 int error = 0; 184 185 switch (type) { 186 case MOD_LOAD: 187 random_buf = (void *)malloc(PAGE_SIZE, M_TEMP, M_WAITOK); 188 random_ident_hardware(&random_systat); 189 mtx_init(&random_systat.lock, "entropy device lock", 190 NULL, MTX_DEF); 191 (*random_systat.init)(); 192 193 printf("random: <entropy source, %s>\n", random_systat.ident); 194 195 random_dev = make_dev(&random_cdevsw, RANDOM_MINOR, 196 UID_ROOT, GID_WHEEL, 0666, "random"); 197 make_dev_alias(random_dev, "urandom"); /* XXX Deprecated */ 198 199 break; 200 201 case MOD_UNLOAD: 202 (*random_systat.deinit)(); 203 free(random_buf, M_TEMP); 204 mtx_destroy(&random_systat.lock); 205 206 destroy_dev(random_dev); 207 208 break; 209 210 case MOD_SHUTDOWN: 211 break; 212 213 } 214 return (error); 215 } 216 217 DEV_MODULE(random, random_modevent, NULL); 218