1 /*- 2 * Copyright (c) 1982, 1986, 1989, 1993 3 * The Regents of the University of California. 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 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 4. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 */ 30 31 #include <sys/cdefs.h> 32 __FBSDID("$FreeBSD$"); 33 34 /* 35 * Pseudo-nulmodem driver 36 * Mighty handy for use with serial console in Vmware 37 */ 38 39 #include "opt_compat.h" 40 #include "opt_tty.h" 41 42 #include <sys/param.h> 43 #include <sys/systm.h> 44 #include <sys/proc.h> 45 #include <sys/tty.h> 46 #include <sys/conf.h> 47 #include <sys/fcntl.h> 48 #include <sys/poll.h> 49 #include <sys/kernel.h> 50 #include <sys/module.h> 51 #include <sys/serial.h> 52 #include <sys/signalvar.h> 53 #include <sys/malloc.h> 54 #include <sys/taskqueue.h> 55 56 MALLOC_DEFINE(M_NLMDM, "nullmodem", "nullmodem data structures"); 57 58 static d_close_t nmdmclose; 59 static t_modem_t nmdmmodem; 60 static d_open_t nmdmopen; 61 static t_oproc_t nmdmoproc; 62 static t_param_t nmdmparam; 63 static t_stop_t nmdmstop; 64 65 static void nmdminit(struct cdev *dev); 66 67 68 static struct cdevsw nmdm_cdevsw = { 69 .d_version = D_VERSION, 70 .d_open = nmdmopen, 71 .d_close = nmdmclose, 72 .d_name = "nmdn", 73 .d_flags = D_TTY | D_PSEUDO | D_NEEDGIANT, 74 }; 75 76 #define BUFSIZ 100 /* Chunk size iomoved to/from user */ 77 #define NMDM_MAX_NUM 128 /* Artificially limit # devices. */ 78 #define PF_STOPPED 0x10 /* user told stopped */ 79 #define BFLAG CLONE_FLAG0 80 81 struct softpart { 82 struct tty *nm_tty; 83 struct cdev *dev; 84 int nm_dcd; 85 struct task pt_task; 86 struct softpart *other; 87 struct callout co; 88 u_long quota; 89 u_long accumulator; 90 int rate; 91 int credits; 92 93 #define QS 8 /* Quota shift */ 94 }; 95 96 struct nm_softc { 97 TAILQ_ENTRY(nm_softc) pt_list; 98 int pt_flags; 99 struct softpart part1, part2; 100 struct prison *pt_prison; 101 }; 102 103 static struct clonedevs *nmdmclones; 104 static TAILQ_HEAD(,nm_softc) nmdmhead = TAILQ_HEAD_INITIALIZER(nmdmhead); 105 106 static void 107 nmdm_clone(void *arg, char *name, int nameen, struct cdev **dev) 108 { 109 int i, unit; 110 char *p; 111 struct cdev *d1, *d2; 112 113 if (*dev != NULL) 114 return; 115 if (strcmp(name, "nmdm") == 0) { 116 p = NULL; 117 unit = -1; 118 } else { 119 i = dev_stdclone(name, &p, "nmdm", &unit); 120 if (i == 0) 121 return; 122 if (p[0] != '\0' && p[0] != 'A' && p[0] != 'B') 123 return; 124 else if (p[0] != '\0' && p[1] != '\0') 125 return; 126 } 127 i = clone_create(&nmdmclones, &nmdm_cdevsw, &unit, &d1, 0); 128 if (i) { 129 d1 = make_dev(&nmdm_cdevsw, unit2minor(unit), 130 0, 0, 0666, "nmdm%dA", unit); 131 if (d1 == NULL) 132 return; 133 d2 = make_dev(&nmdm_cdevsw, unit2minor(unit) | BFLAG, 134 0, 0, 0666, "nmdm%dB", unit); 135 if (d2 == NULL) { 136 destroy_dev(d1); 137 return; 138 } 139 d2->si_drv2 = d1; 140 d1->si_drv2 = d2; 141 dev_depends(d1, d2); 142 dev_depends(d2, d1); 143 d1->si_flags |= SI_CHEAPCLONE; 144 d2->si_flags |= SI_CHEAPCLONE; 145 } 146 if (p != NULL && p[0] == 'B') 147 *dev = d1->si_drv2; 148 else 149 *dev = d1; 150 } 151 152 static void 153 nmdm_timeout(void *arg) 154 { 155 struct softpart *sp; 156 157 sp = arg; 158 159 if (sp->rate == 0) 160 return; 161 162 /* 163 * Do a simple Floyd-Steinberg dither here to avoid FP math. 164 * Wipe out unused quota from last tick. 165 */ 166 sp->accumulator += sp->credits; 167 sp->quota = sp->accumulator >> QS; 168 sp->accumulator &= ((1 << QS) - 1); 169 170 taskqueue_enqueue(taskqueue_swi_giant, &sp->pt_task); 171 callout_reset(&sp->co, sp->rate, nmdm_timeout, arg); 172 } 173 174 static void 175 nmdm_task_tty(void *arg, int pending __unused) 176 { 177 struct tty *tp, *otp; 178 struct softpart *sp; 179 int c; 180 181 tp = arg; 182 sp = tp->t_sc; 183 otp = sp->other->nm_tty; 184 KASSERT(otp != NULL, ("NULL otp in nmdmstart")); 185 KASSERT(otp != tp, ("NULL otp == tp nmdmstart")); 186 if (sp->other->nm_dcd) { 187 if (!(tp->t_state & TS_ISOPEN)) { 188 sp->other->nm_dcd = 0; 189 (void)ttyld_modem(otp, 0); 190 } 191 } else { 192 if (tp->t_state & TS_ISOPEN) { 193 sp->other->nm_dcd = 1; 194 (void)ttyld_modem(otp, 1); 195 } 196 } 197 if (tp->t_state & TS_TTSTOP) 198 return; 199 while (tp->t_outq.c_cc != 0) { 200 if (sp->rate && !sp->quota) 201 return; 202 if (otp->t_state & TS_TBLOCK) 203 return; 204 sp->quota--; 205 c = getc(&tp->t_outq); 206 if (otp->t_state & TS_ISOPEN) 207 ttyld_rint(otp, c); 208 } 209 if (tp->t_outq.c_cc == 0) 210 ttwwakeup(tp); 211 212 } 213 214 /* 215 * This function creates and initializes a pair of ttys. 216 */ 217 static void 218 nmdminit(struct cdev *dev1) 219 { 220 struct cdev *dev2; 221 struct nm_softc *pt; 222 223 dev2 = dev1->si_drv2; 224 225 dev1->si_flags &= ~SI_CHEAPCLONE; 226 dev2->si_flags &= ~SI_CHEAPCLONE; 227 228 pt = malloc(sizeof(*pt), M_NLMDM, M_WAITOK | M_ZERO); 229 TAILQ_INSERT_TAIL(&nmdmhead, pt, pt_list); 230 231 dev1->si_drv1 = dev2->si_drv1 = pt; 232 233 pt->part1.dev = dev1; 234 pt->part2.dev = dev2; 235 236 pt->part1.nm_tty = ttymalloc(pt->part1.nm_tty); 237 pt->part1.nm_tty->t_oproc = nmdmoproc; 238 pt->part1.nm_tty->t_stop = nmdmstop; 239 pt->part1.nm_tty->t_modem = nmdmmodem; 240 pt->part1.nm_tty->t_param = nmdmparam; 241 pt->part1.nm_tty->t_dev = dev1; 242 pt->part1.nm_tty->t_sc = &pt->part1; 243 TASK_INIT(&pt->part1.pt_task, 0, nmdm_task_tty, pt->part1.nm_tty); 244 callout_init(&pt->part1.co, 0); 245 246 pt->part2.nm_tty = ttymalloc(pt->part2.nm_tty); 247 pt->part2.nm_tty->t_oproc = nmdmoproc; 248 pt->part2.nm_tty->t_stop = nmdmstop; 249 pt->part2.nm_tty->t_modem = nmdmmodem; 250 pt->part2.nm_tty->t_param = nmdmparam; 251 pt->part2.nm_tty->t_dev = dev2; 252 pt->part2.nm_tty->t_sc = &pt->part2; 253 TASK_INIT(&pt->part2.pt_task, 0, nmdm_task_tty, pt->part2.nm_tty); 254 callout_init(&pt->part2.co, 0); 255 256 pt->part1.other = &pt->part2; 257 pt->part2.other = &pt->part1; 258 259 dev1->si_tty = pt->part1.nm_tty; 260 dev1->si_drv1 = pt; 261 262 dev2->si_tty = pt->part2.nm_tty; 263 dev2->si_drv1 = pt; 264 } 265 266 /* 267 * Device opened from userland 268 */ 269 static int 270 nmdmopen(struct cdev *dev, int flag, int devtype, struct thread *td) 271 { 272 struct tty *tp, *tp2; 273 int error; 274 struct nm_softc *pti; 275 struct softpart *sp; 276 277 if (dev->si_drv1 == NULL) 278 nmdminit(dev); 279 pti = dev->si_drv1; 280 if (pti->pt_prison != td->td_ucred->cr_prison) 281 return (EBUSY); 282 283 tp = dev->si_tty; 284 sp = tp->t_sc; 285 tp2 = sp->other->nm_tty; 286 287 if ((tp->t_state & TS_ISOPEN) == 0) { 288 ttyinitmode(tp, 0, 0); 289 ttsetwater(tp); /* XXX ? */ 290 } else if (tp->t_state & TS_XCLUDE && suser(td)) { 291 return (EBUSY); 292 } 293 294 error = ttyld_open(tp, dev); 295 return (error); 296 } 297 298 static int 299 bits_per_char(struct termios *t) 300 { 301 int bits; 302 303 bits = 1; /* start bit */ 304 switch (t->c_cflag & CSIZE) { 305 case CS5: bits += 5; break; 306 case CS6: bits += 6; break; 307 case CS7: bits += 7; break; 308 case CS8: bits += 8; break; 309 } 310 bits++; /* stop bit */ 311 if (t->c_cflag & PARENB) 312 bits++; 313 if (t->c_cflag & CSTOPB) 314 bits++; 315 return (bits); 316 } 317 318 static int 319 nmdmparam(struct tty *tp, struct termios *t) 320 { 321 struct softpart *sp; 322 struct tty *tp2; 323 int bpc, rate, speed, i; 324 325 sp = tp->t_sc; 326 tp2 = sp->other->nm_tty; 327 328 if (!((t->c_cflag | tp2->t_cflag) & CDSR_OFLOW)) { 329 sp->rate = 0; 330 sp->other->rate = 0; 331 return (0); 332 } 333 334 /* 335 * DSRFLOW one either side enables rate-simulation for both 336 * directions. 337 * NB: the two directions may run at different rates. 338 */ 339 340 /* Find the larger of the number of bits transmitted */ 341 bpc = imax(bits_per_char(t), bits_per_char(&tp2->t_termios)); 342 343 for (i = 0; i < 2; i++) { 344 /* Use the slower of our receive and their transmit rate */ 345 speed = imin(tp2->t_ospeed, t->c_ispeed); 346 if (speed == 0) { 347 sp->rate = 0; 348 sp->other->rate = 0; 349 return (0); 350 } 351 352 speed <<= QS; /* [bit/sec, scaled] */ 353 speed /= bpc; /* [char/sec, scaled] */ 354 rate = (hz << QS) / speed; /* [hz per callout] */ 355 if (rate == 0) 356 rate = 1; 357 358 speed *= rate; 359 speed /= hz; /* [(char/sec)/tick, scaled */ 360 361 sp->credits = speed; 362 sp->rate = rate; 363 callout_reset(&sp->co, rate, nmdm_timeout, sp); 364 365 /* 366 * swap pointers for second pass so the other end gets 367 * updated as well. 368 */ 369 sp = sp->other; 370 t = &tp2->t_termios; 371 tp2 = tp; 372 } 373 return (0); 374 } 375 376 static int 377 nmdmmodem(struct tty *tp, int sigon, int sigoff) 378 { 379 struct softpart *sp; 380 int i; 381 382 sp = tp->t_sc; 383 if (sigon || sigoff) { 384 if (sigon & SER_DTR) 385 sp->other->nm_dcd = 1; 386 if (sigoff & SER_DTR) 387 sp->other->nm_dcd = 0; 388 ttyld_modem(sp->other->nm_tty, sp->other->nm_dcd); 389 return (0); 390 } else { 391 i = 0; 392 if (sp->nm_dcd) 393 i |= SER_DCD; 394 if (sp->other->nm_dcd) 395 i |= SER_DTR; 396 return (i); 397 } 398 } 399 400 static int 401 nmdmclose(struct cdev *dev, int flag, int mode, struct thread *td) 402 { 403 404 return (tty_close(dev->si_tty)); 405 } 406 407 static void 408 nmdmoproc(struct tty *tp) 409 { 410 struct softpart *pt; 411 412 pt = tp->t_sc; 413 taskqueue_enqueue(taskqueue_swi_giant, &pt->pt_task); 414 } 415 416 static void 417 nmdmstop(struct tty *tp, int flush) 418 { 419 struct softpart *pt; 420 421 pt = tp->t_sc; 422 taskqueue_enqueue(taskqueue_swi_giant, &pt->pt_task); 423 } 424 425 /* 426 * Module handling 427 */ 428 static int 429 nmdm_modevent(module_t mod, int type, void *data) 430 { 431 static eventhandler_tag tag; 432 struct nm_softc *pt, *tpt; 433 int error = 0; 434 435 switch(type) { 436 case MOD_LOAD: 437 clone_setup(&nmdmclones); 438 tag = EVENTHANDLER_REGISTER(dev_clone, nmdm_clone, 0, 1000); 439 if (tag == NULL) 440 return (ENOMEM); 441 break; 442 443 case MOD_SHUTDOWN: 444 /* FALLTHROUGH */ 445 case MOD_UNLOAD: 446 EVENTHANDLER_DEREGISTER(dev_clone, tag); 447 TAILQ_FOREACH_SAFE(pt, &nmdmhead, pt_list, tpt) { 448 destroy_dev(pt->part1.dev); 449 TAILQ_REMOVE(&nmdmhead, pt, pt_list); 450 free(pt, M_NLMDM); 451 } 452 clone_cleanup(&nmdmclones); 453 break; 454 default: 455 error = EOPNOTSUPP; 456 } 457 return (error); 458 } 459 460 DEV_MODULE(nmdm, nmdm_modevent, NULL); 461