randomdev.c revision 128059
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 128059 2004-04-09 15:47:10Z markm $"); 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> 4176166Smarkm#include <sys/mutex.h> 4267112Smarkm#include <sys/poll.h> 4383366Sjulian#include <sys/proc.h> 4470834Swollman#include <sys/selinfo.h> 4576166Smarkm#include <sys/uio.h> 4676166Smarkm#include <sys/unistd.h> 4767112Smarkm#include <sys/vnode.h> 4874072Smarkm 4962053Smarkm#include <machine/bus.h> 5074072Smarkm#include <machine/cpu.h> 5162053Smarkm 5274072Smarkm#include <dev/random/randomdev.h> 5362053Smarkm 54122871Smarkm#define RANDOM_MINOR 0 5562053Smarkm 56128059Smarkmstatic d_close_t random_close; 57128059Smarkmstatic d_read_t random_read; 58128059Smarkmstatic d_write_t random_write; 59128059Smarkmstatic d_ioctl_t random_ioctl; 60128059Smarkmstatic d_poll_t random_poll; 61122871Smarkm 6262053Smarkmstatic struct cdevsw random_cdevsw = { 63128059Smarkm .d_version = D_VERSION, 64128059Smarkm .d_close = random_close, 65128059Smarkm .d_read = random_read, 66128059Smarkm .d_write = random_write, 67128059Smarkm .d_ioctl = random_ioctl, 68128059Smarkm .d_poll = random_poll, 69128059Smarkm .d_name = "random", 7062053Smarkm}; 7162053Smarkm 72128059Smarkmstatic void *random_buf; 7374072Smarkm 74128059Smarkmstruct random_systat random_systat; 7574072Smarkm 7662053Smarkm/* For use with make_dev(9)/destroy_dev(9). */ 77128059Smarkmstatic dev_t 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 87128059Smarkmrandom_close(dev_t 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 mtx_lock(&random_systat.lock); 93128059Smarkm (*random_systat.reseed)(); 94128059Smarkm random_systat.seeded = 1; 95128059Smarkm mtx_unlock(&random_systat.lock); 9683976Srwatson } 97128059Smarkm return (0); 9869172Smarkm} 9969172Smarkm 10091600Smarkm/* ARGSUSED */ 10169172Smarkmstatic int 10291600Smarkmrandom_read(dev_t dev __unused, struct uio *uio, int flag) 10362053Smarkm{ 104128059Smarkm int c, error = 0; 10562053Smarkm 106128059Smarkm /* Blocking logic */ 107128059Smarkm while (!random_systat.seeded && !error) { 10867286Speter if (flag & IO_NDELAY) 109128059Smarkm error = EWOULDBLOCK; 11067112Smarkm else 111128059Smarkm error = tsleep(&random_systat, 112128059Smarkm PUSER | PCATCH, "block", 0); 11367112Smarkm } 114128059Smarkm 115128059Smarkm /* The actual read */ 116128059Smarkm if (!error) { 117128059Smarkm mtx_lock(&random_systat.lock); 118128059Smarkm while (uio->uio_resid > 0 && !error) { 119128059Smarkm c = MIN(uio->uio_resid, PAGE_SIZE); 120128059Smarkm c = (*random_systat.read)(random_buf, c); 121128059Smarkm error = uiomove(random_buf, c, uio); 122128059Smarkm } 123128059Smarkm mtx_unlock(&random_systat.lock); 12467286Speter } 125128059Smarkm return (error); 12662053Smarkm} 12762053Smarkm 12891600Smarkm/* ARGSUSED */ 12962053Smarkmstatic int 13091600Smarkmrandom_write(dev_t dev __unused, struct uio *uio, int flag __unused) 13162053Smarkm{ 132128059Smarkm int c, error = 0; 13362053Smarkm 134128059Smarkm mtx_lock(&random_systat.lock); 13562053Smarkm while (uio->uio_resid > 0) { 136128059Smarkm c = MIN((int)uio->uio_resid, PAGE_SIZE); 13762765Smarkm error = uiomove(random_buf, c, uio); 13862053Smarkm if (error) 13962053Smarkm break; 140128059Smarkm (*random_systat.write)(random_buf, c); 14162053Smarkm } 142128059Smarkm mtx_unlock(&random_systat.lock); 143128059Smarkm return (error); 14462053Smarkm} 14562053Smarkm 14691600Smarkm/* ARGSUSED */ 14762053Smarkmstatic int 14891600Smarkmrandom_ioctl(dev_t dev __unused, u_long cmd, caddr_t addr __unused, 14991600Smarkm int flags __unused, struct thread *td __unused) 15065686Smarkm{ 151128059Smarkm int error = 0; 152128059Smarkm 15374771Smarkm switch (cmd) { 154128059Smarkm /* Really handled in upper layer */ 15574771Smarkm case FIOASYNC: 15674771Smarkm case FIONBIO: 157128059Smarkm break; 15874771Smarkm default: 159128059Smarkm error = ENOTTY; 16074771Smarkm } 161128059Smarkm return (error); 16265686Smarkm} 16365686Smarkm 16491600Smarkm/* ARGSUSED */ 16565686Smarkmstatic int 16691600Smarkmrandom_poll(dev_t dev __unused, int events, struct thread *td) 16767112Smarkm{ 168128059Smarkm int revents = 0; 16967112Smarkm 17067112Smarkm if (events & (POLLIN | POLLRDNORM)) { 17174072Smarkm if (random_systat.seeded) 17267112Smarkm revents = events & (POLLIN | POLLRDNORM); 17367112Smarkm else 17483805Sjhb selrecord(td, &random_systat.rsel); 17567112Smarkm } 176128059Smarkm return (revents); 17767112Smarkm} 17867112Smarkm 17991600Smarkm/* ARGSUSED */ 18067112Smarkmstatic int 18191600Smarkmrandom_modevent(module_t mod __unused, int type, void *data __unused) 18262053Smarkm{ 183128059Smarkm int error = 0; 18465686Smarkm 185128059Smarkm switch (type) { 18662053Smarkm case MOD_LOAD: 187128059Smarkm random_buf = (void *)malloc(PAGE_SIZE, M_TEMP, M_WAITOK); 188128059Smarkm random_ident_hardware(&random_systat); 189128059Smarkm mtx_init(&random_systat.lock, "entropy device lock", 190128059Smarkm NULL, MTX_DEF); 191128059Smarkm (*random_systat.init)(); 19271037Smarkm 193128059Smarkm printf("random: <entropy source, %s>\n", random_systat.ident); 19471037Smarkm 195128059Smarkm random_dev = make_dev(&random_cdevsw, RANDOM_MINOR, 196128059Smarkm UID_ROOT, GID_WHEEL, 0666, "random"); 197128059Smarkm make_dev_alias(random_dev, "urandom"); /* XXX Deprecated */ 19874072Smarkm 199128059Smarkm break; 20074072Smarkm 20162053Smarkm case MOD_UNLOAD: 202128059Smarkm (*random_systat.deinit)(); 203128059Smarkm free(random_buf, M_TEMP); 204128059Smarkm mtx_destroy(&random_systat.lock); 20574072Smarkm 206128059Smarkm destroy_dev(random_dev); 20774072Smarkm 208128059Smarkm break; 209122871Smarkm 21062053Smarkm case MOD_SHUTDOWN: 211128059Smarkm break; 21262053Smarkm 21362053Smarkm } 214128059Smarkm return (error); 21562053Smarkm} 21662053Smarkm 21762053SmarkmDEV_MODULE(random, random_modevent, NULL); 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