randomdev.c revision 131398
162053Smarkm/*- 2128059Smarkm * Copyright (c) 2000-2004 Mark R V Murray 362053Smarkm * All rights reserved. 462053Smarkm * 562053Smarkm * Redistribution and use in source and binary forms, with or without 662053Smarkm * modification, are permitted provided that the following conditions 762053Smarkm * are met: 862053Smarkm * 1. Redistributions of source code must retain the above copyright 962053Smarkm * notice, this list of conditions and the following disclaimer 1062053Smarkm * in this position and unchanged. 1162053Smarkm * 2. Redistributions in binary form must reproduce the above copyright 1262053Smarkm * notice, this list of conditions and the following disclaimer in the 1362053Smarkm * documentation and/or other materials provided with the distribution. 1462053Smarkm * 1562053Smarkm * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 1662053Smarkm * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 1762053Smarkm * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 1862053Smarkm * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 1962053Smarkm * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 2062053Smarkm * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 2162053Smarkm * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 2262053Smarkm * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 2362053Smarkm * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 2462053Smarkm * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 2562053Smarkm * 2662053Smarkm */ 2762053Smarkm 28119418Sobrien#include <sys/cdefs.h> 29119418Sobrien__FBSDID("$FreeBSD: head/sys/dev/random/randomdev.c 131398 2004-07-01 07:46:29Z jhb $"); 30119418Sobrien 3162053Smarkm#include <sys/param.h> 3262053Smarkm#include <sys/systm.h> 3376166Smarkm#include <sys/bus.h> 3462053Smarkm#include <sys/conf.h> 3576166Smarkm#include <sys/fcntl.h> 3674771Smarkm#include <sys/filio.h> 3762053Smarkm#include <sys/kernel.h> 3874072Smarkm#include <sys/kthread.h> 3976166Smarkm#include <sys/lock.h> 4062053Smarkm#include <sys/malloc.h> 41129876Sphk#include <sys/module.h> 4276166Smarkm#include <sys/mutex.h> 4367112Smarkm#include <sys/poll.h> 4483366Sjulian#include <sys/proc.h> 4570834Swollman#include <sys/selinfo.h> 4676166Smarkm#include <sys/uio.h> 4776166Smarkm#include <sys/unistd.h> 4867112Smarkm#include <sys/vnode.h> 4974072Smarkm 5062053Smarkm#include <machine/bus.h> 5174072Smarkm#include <machine/cpu.h> 5262053Smarkm 5374072Smarkm#include <dev/random/randomdev.h> 5462053Smarkm 55122871Smarkm#define RANDOM_MINOR 0 5662053Smarkm 57128059Smarkmstatic d_close_t random_close; 58128059Smarkmstatic d_read_t random_read; 59128059Smarkmstatic d_write_t random_write; 60128059Smarkmstatic d_ioctl_t random_ioctl; 61128059Smarkmstatic d_poll_t random_poll; 62122871Smarkm 6362053Smarkmstatic struct cdevsw random_cdevsw = { 64128059Smarkm .d_version = D_VERSION, 65128321Smarkm .d_flags = D_NEEDGIANT, 66128059Smarkm .d_close = random_close, 67128059Smarkm .d_read = random_read, 68128059Smarkm .d_write = random_write, 69128059Smarkm .d_ioctl = random_ioctl, 70128059Smarkm .d_poll = random_poll, 71128059Smarkm .d_name = "random", 7262053Smarkm}; 7362053Smarkm 74128059Smarkmstruct random_systat random_systat; 7574072Smarkm 7662053Smarkm/* For use with make_dev(9)/destroy_dev(9). */ 77130585Sphkstatic struct cdev *random_dev; 7862053Smarkm 79128059Smarkm/* Used to fake out unused random calls in random_systat */ 80128059Smarkmvoid 81128059Smarkmrandom_null_func(void) 8274072Smarkm{ 8374072Smarkm} 8462053Smarkm 8591600Smarkm/* ARGSUSED */ 8662053Smarkmstatic int 87130585Sphkrandom_close(struct cdev *dev __unused, int flags, int fmt __unused, 88128059Smarkm struct thread *td) 8969172Smarkm{ 90128059Smarkm if ((flags & FWRITE) && (suser(td) == 0) 91128059Smarkm && (securelevel_gt(td->td_ucred, 0) == 0)) { 92128059Smarkm (*random_systat.reseed)(); 93128059Smarkm random_systat.seeded = 1; 9483976Srwatson } 95128321Smarkm 96128059Smarkm return (0); 9769172Smarkm} 9869172Smarkm 9991600Smarkm/* ARGSUSED */ 10069172Smarkmstatic int 101130585Sphkrandom_read(struct cdev *dev __unused, struct uio *uio, int flag) 10262053Smarkm{ 103128059Smarkm int c, error = 0; 104128367Smarkm void *random_buf; 10562053Smarkm 106128059Smarkm /* Blocking logic */ 107128059Smarkm while (!random_systat.seeded && !error) { 10867286Speter if (flag & IO_NDELAY) 109128059Smarkm error = EWOULDBLOCK; 110128321Smarkm else { 111128321Smarkm /* No complaints please. This is temporary! */ 112128321Smarkm printf("Entropy device is blocking. " 113128321Smarkm "Dance fandango on keyboard to unblock.\n"); 114128321Smarkm error = tsleep(&random_systat, 115128059Smarkm PUSER | PCATCH, "block", 0); 116128321Smarkm } 11767112Smarkm } 118128059Smarkm 119128059Smarkm /* The actual read */ 120128059Smarkm if (!error) { 121128367Smarkm 122128367Smarkm random_buf = (void *)malloc(PAGE_SIZE, M_TEMP, M_WAITOK); 123128367Smarkm 124128059Smarkm while (uio->uio_resid > 0 && !error) { 125128059Smarkm c = MIN(uio->uio_resid, PAGE_SIZE); 126128059Smarkm c = (*random_systat.read)(random_buf, c); 127128059Smarkm error = uiomove(random_buf, c, uio); 128128059Smarkm } 129128367Smarkm 130128367Smarkm free(random_buf, M_TEMP); 131128367Smarkm 13267286Speter } 133128151Smarkm 134128059Smarkm return (error); 13562053Smarkm} 13662053Smarkm 13791600Smarkm/* ARGSUSED */ 13862053Smarkmstatic int 139130585Sphkrandom_write(struct cdev *dev __unused, struct uio *uio, int flag __unused) 14062053Smarkm{ 141128059Smarkm int c, error = 0; 142128367Smarkm void *random_buf; 14362053Smarkm 144128367Smarkm random_buf = (void *)malloc(PAGE_SIZE, M_TEMP, M_WAITOK); 145128367Smarkm 14662053Smarkm while (uio->uio_resid > 0) { 147128059Smarkm c = MIN((int)uio->uio_resid, PAGE_SIZE); 14862765Smarkm error = uiomove(random_buf, c, uio); 14962053Smarkm if (error) 15062053Smarkm break; 151128059Smarkm (*random_systat.write)(random_buf, c); 15262053Smarkm } 153128321Smarkm 154128367Smarkm free(random_buf, M_TEMP); 155128367Smarkm 156128059Smarkm return (error); 15762053Smarkm} 15862053Smarkm 15991600Smarkm/* ARGSUSED */ 16062053Smarkmstatic int 161130585Sphkrandom_ioctl(struct cdev *dev __unused, u_long cmd, caddr_t addr __unused, 16291600Smarkm int flags __unused, struct thread *td __unused) 16365686Smarkm{ 164128059Smarkm int error = 0; 165128059Smarkm 16674771Smarkm switch (cmd) { 167128059Smarkm /* Really handled in upper layer */ 16874771Smarkm case FIOASYNC: 16974771Smarkm case FIONBIO: 170128059Smarkm break; 17174771Smarkm default: 172128059Smarkm error = ENOTTY; 17374771Smarkm } 174128059Smarkm return (error); 17565686Smarkm} 17665686Smarkm 17791600Smarkm/* ARGSUSED */ 17865686Smarkmstatic int 179130585Sphkrandom_poll(struct cdev *dev __unused, int events, struct thread *td) 18067112Smarkm{ 181128059Smarkm int revents = 0; 18267112Smarkm 18367112Smarkm if (events & (POLLIN | POLLRDNORM)) { 18474072Smarkm if (random_systat.seeded) 18567112Smarkm revents = events & (POLLIN | POLLRDNORM); 18667112Smarkm else 18783805Sjhb selrecord(td, &random_systat.rsel); 18867112Smarkm } 189128059Smarkm return (revents); 19067112Smarkm} 19167112Smarkm 19291600Smarkm/* ARGSUSED */ 19367112Smarkmstatic int 19491600Smarkmrandom_modevent(module_t mod __unused, int type, void *data __unused) 19562053Smarkm{ 196128059Smarkm int error = 0; 19765686Smarkm 198128059Smarkm switch (type) { 19962053Smarkm case MOD_LOAD: 200128059Smarkm random_ident_hardware(&random_systat); 201128059Smarkm (*random_systat.init)(); 20271037Smarkm 203131398Sjhb if (bootverbose) 204131398Sjhb printf("random: <entropy source, %s>\n", 205131398Sjhb random_systat.ident); 20671037Smarkm 207128059Smarkm random_dev = make_dev(&random_cdevsw, RANDOM_MINOR, 208128059Smarkm UID_ROOT, GID_WHEEL, 0666, "random"); 209128059Smarkm make_dev_alias(random_dev, "urandom"); /* XXX Deprecated */ 21074072Smarkm 211128059Smarkm break; 21274072Smarkm 21362053Smarkm case MOD_UNLOAD: 214128059Smarkm (*random_systat.deinit)(); 21574072Smarkm 216128059Smarkm destroy_dev(random_dev); 21774072Smarkm 218128059Smarkm break; 219122871Smarkm 22062053Smarkm case MOD_SHUTDOWN: 221128059Smarkm break; 22262053Smarkm 22362053Smarkm } 224128059Smarkm return (error); 22562053Smarkm} 22662053Smarkm 22762053SmarkmDEV_MODULE(random, random_modevent, NULL); 228