1 /* 2 * Copyright (c) 1995 Ugen J.S.Antsilevich 3 * 4 * Redistribution and use in source forms, with and without modification, 5 * are permitted provided that this entire comment appears intact. 6 * 7 * Redistribution in binary form may occur without any restrictions. 8 * Obviously, it would be nice if you gave credit where credit is due 9 * but requiring it would be too onerous. 10 * 11 * This software is provided ``AS IS'' without any warranties of any kind. 12 * 13 * Snoop stuff. 14 * 15 * $FreeBSD$ 16 */ 17 18 #include <sys/param.h> 19 #include <sys/systm.h> 20 #include <sys/filio.h> 21 #include <sys/malloc.h> 22 #include <sys/tty.h> 23 #include <sys/conf.h> 24 #include <sys/poll.h> 25 #include <sys/kernel.h> 26 #include <sys/snoop.h> 27 #include <sys/vnode.h> 28 29 static l_close_t snplclose; 30 static l_write_t snplwrite; 31 static d_open_t snpopen; 32 static d_close_t snpclose; 33 static d_read_t snpread; 34 static d_write_t snpwrite; 35 static d_ioctl_t snpioctl; 36 static d_poll_t snppoll; 37 38 #define CDEV_MAJOR 53 39 static struct cdevsw snp_cdevsw = { 40 /* open */ snpopen, 41 /* close */ snpclose, 42 /* read */ snpread, 43 /* write */ snpwrite, 44 /* ioctl */ snpioctl, 45 /* poll */ snppoll, 46 /* mmap */ nommap, 47 /* strategy */ nostrategy, 48 /* name */ "snp", 49 /* maj */ CDEV_MAJOR, 50 /* dump */ nodump, 51 /* psize */ nopsize, 52 /* flags */ 0, 53 }; 54 55 static struct linesw snpdisc = { 56 ttyopen, snplclose, ttread, snplwrite, 57 l_nullioctl, ttyinput, ttstart, ttymodem 58 }; 59 60 static MALLOC_DEFINE(M_SNP, "snp", "Snoop device data"); 61 /* 62 * The number of the "snoop" line discipline. This gets determined at 63 * module load time. 64 */ 65 static int snooplinedisc; 66 67 static struct tty *snpdevtotty __P((dev_t dev)); 68 static void snp_clone __P((void *arg, char *name, 69 int namelen, dev_t *dev)); 70 static int snp_detach __P((struct snoop *snp)); 71 static int snp_down __P((struct snoop *snp)); 72 static int snp_in __P((struct snoop *snp, char *buf, int n)); 73 static int snp_modevent __P((module_t mod, int what, void *arg)); 74 75 static int 76 snplclose(tp, flag) 77 struct tty *tp; 78 int flag; 79 { 80 struct snoop *snp; 81 int error; 82 83 snp = tp->t_sc; 84 error = snp_down(snp); 85 if (error != 0) 86 return (error); 87 error = ttylclose(tp, flag); 88 return (error); 89 } 90 91 static int 92 snplwrite(tp, uio, flag) 93 struct tty *tp; 94 struct uio *uio; 95 int flag; 96 { 97 struct iovec iov; 98 struct uio uio2; 99 struct snoop *snp; 100 int error, ilen; 101 char ibuf[512]; 102 103 snp = tp->t_sc; 104 while (uio->uio_resid > 0) { 105 ilen = imin(sizeof(ibuf), uio->uio_resid); 106 error = uiomove(ibuf, ilen, uio); 107 if (error != 0) 108 return (error); 109 snp_in(snp, ibuf, ilen); 110 /* Hackish, but probably the least of all evils. */ 111 iov.iov_base = ibuf; 112 iov.iov_len = ilen; 113 uio2.uio_iov = &iov; 114 uio2.uio_iovcnt = 1; 115 uio2.uio_offset = 0; 116 uio2.uio_resid = ilen; 117 uio2.uio_segflg = UIO_SYSSPACE; 118 uio2.uio_rw = UIO_WRITE; 119 uio2.uio_procp = uio->uio_procp; 120 error = ttwrite(tp, &uio2, flag); 121 if (error != 0) 122 return (error); 123 } 124 return (0); 125 } 126 127 static struct tty * 128 snpdevtotty(dev) 129 dev_t dev; 130 { 131 struct cdevsw *cdp; 132 133 cdp = devsw(dev); 134 if (cdp == NULL || (cdp->d_flags & D_TTY) == 0) 135 return (NULL); 136 return (dev->si_tty); 137 } 138 139 #define SNP_INPUT_BUF 5 /* This is even too much, the maximal 140 * interactive mode write is 3 bytes 141 * length for function keys... 142 */ 143 144 static int 145 snpwrite(dev, uio, flag) 146 dev_t dev; 147 struct uio *uio; 148 int flag; 149 { 150 struct snoop *snp; 151 struct tty *tp; 152 int error, i, len; 153 char c[SNP_INPUT_BUF]; 154 155 snp = dev->si_drv1; 156 tp = snp->snp_tty; 157 if (tp == NULL) 158 return (EIO); 159 if ((tp->t_sc == snp) && (tp->t_state & TS_SNOOP) && 160 tp->t_line == snooplinedisc) 161 goto tty_input; 162 163 printf("Snoop: attempt to write to bad tty.\n"); 164 return (EIO); 165 166 tty_input: 167 if (!(tp->t_state & TS_ISOPEN)) 168 return (EIO); 169 170 while (uio->uio_resid > 0) { 171 len = imin(uio->uio_resid, SNP_INPUT_BUF); 172 if ((error = uiomove(c, len, uio)) != 0) 173 return (error); 174 for (i=0; i < len; i++) { 175 if (ttyinput(c[i], tp)) 176 return (EIO); 177 } 178 } 179 return (0); 180 } 181 182 183 static int 184 snpread(dev, uio, flag) 185 dev_t dev; 186 struct uio *uio; 187 int flag; 188 { 189 struct snoop *snp; 190 int error, len, n, nblen, s; 191 caddr_t from; 192 char *nbuf; 193 194 snp = dev->si_drv1; 195 KASSERT(snp->snp_len + snp->snp_base <= snp->snp_blen, 196 ("snoop buffer error")); 197 198 if (snp->snp_tty == NULL) 199 return (EIO); 200 201 snp->snp_flags &= ~SNOOP_RWAIT; 202 203 do { 204 if (snp->snp_len == 0) { 205 if (flag & IO_NDELAY) 206 return (EWOULDBLOCK); 207 snp->snp_flags |= SNOOP_RWAIT; 208 tsleep((caddr_t)snp, (PZERO + 1) | PCATCH, "snprd", 0); 209 } 210 } while (snp->snp_len == 0); 211 212 n = snp->snp_len; 213 214 error = 0; 215 while (snp->snp_len > 0 && uio->uio_resid > 0 && error == 0) { 216 len = min((unsigned)uio->uio_resid, snp->snp_len); 217 from = (caddr_t)(snp->snp_buf + snp->snp_base); 218 if (len == 0) 219 break; 220 221 error = uiomove(from, len, uio); 222 snp->snp_base += len; 223 snp->snp_len -= len; 224 } 225 if ((snp->snp_flags & SNOOP_OFLOW) && (n < snp->snp_len)) { 226 snp->snp_flags &= ~SNOOP_OFLOW; 227 } 228 s = spltty(); 229 nblen = snp->snp_blen; 230 if (((nblen / 2) >= SNOOP_MINLEN) && (nblen / 2) >= snp->snp_len) { 231 while (nblen / 2 >= snp->snp_len && nblen / 2 >= SNOOP_MINLEN) 232 nblen = nblen / 2; 233 if ((nbuf = malloc(nblen, M_SNP, M_NOWAIT)) != NULL) { 234 bcopy(snp->snp_buf + snp->snp_base, nbuf, snp->snp_len); 235 free(snp->snp_buf, M_SNP); 236 snp->snp_buf = nbuf; 237 snp->snp_blen = nblen; 238 snp->snp_base = 0; 239 } 240 } 241 splx(s); 242 243 return (error); 244 } 245 246 static int 247 snp_in(snp, buf, n) 248 struct snoop *snp; 249 char *buf; 250 int n; 251 { 252 int s_free, s_tail; 253 int s, len, nblen; 254 caddr_t from, to; 255 char *nbuf; 256 257 KASSERT(n >= 0, ("negative snoop char count")); 258 259 if (n == 0) 260 return (0); 261 262 if (snp->snp_flags & SNOOP_DOWN) { 263 printf("Snoop: more data to down interface.\n"); 264 return (0); 265 } 266 267 if (snp->snp_flags & SNOOP_OFLOW) { 268 printf("Snoop: buffer overflow.\n"); 269 /* 270 * On overflow we just repeat the standart close 271 * procedure...yes , this is waste of space but.. Then next 272 * read from device will fail if one would recall he is 273 * snooping and retry... 274 */ 275 276 return (snp_down(snp)); 277 } 278 s_tail = snp->snp_blen - (snp->snp_len + snp->snp_base); 279 s_free = snp->snp_blen - snp->snp_len; 280 281 282 if (n > s_free) { 283 s = spltty(); 284 nblen = snp->snp_blen; 285 while ((n > s_free) && ((nblen * 2) <= SNOOP_MAXLEN)) { 286 nblen = snp->snp_blen * 2; 287 s_free = nblen - (snp->snp_len + snp->snp_base); 288 } 289 if ((n <= s_free) && (nbuf = malloc(nblen, M_SNP, M_NOWAIT))) { 290 bcopy(snp->snp_buf + snp->snp_base, nbuf, snp->snp_len); 291 free(snp->snp_buf, M_SNP); 292 snp->snp_buf = nbuf; 293 snp->snp_blen = nblen; 294 snp->snp_base = 0; 295 } else { 296 snp->snp_flags |= SNOOP_OFLOW; 297 if (snp->snp_flags & SNOOP_RWAIT) { 298 snp->snp_flags &= ~SNOOP_RWAIT; 299 wakeup((caddr_t)snp); 300 } 301 splx(s); 302 return (0); 303 } 304 splx(s); 305 } 306 if (n > s_tail) { 307 from = (caddr_t)(snp->snp_buf + snp->snp_base); 308 to = (caddr_t)(snp->snp_buf); 309 len = snp->snp_len; 310 bcopy(from, to, len); 311 snp->snp_base = 0; 312 } 313 to = (caddr_t)(snp->snp_buf + snp->snp_base + snp->snp_len); 314 bcopy(buf, to, n); 315 snp->snp_len += n; 316 317 if (snp->snp_flags & SNOOP_RWAIT) { 318 snp->snp_flags &= ~SNOOP_RWAIT; 319 wakeup((caddr_t)snp); 320 } 321 selwakeup(&snp->snp_sel); 322 snp->snp_sel.si_pid = 0; 323 324 return (n); 325 } 326 327 static int 328 snpopen(dev, flag, mode, p) 329 dev_t dev; 330 int flag, mode; 331 struct proc *p; 332 { 333 struct snoop *snp; 334 int error; 335 336 if ((error = suser(p)) != 0) 337 return (error); 338 339 if (dev->si_drv1 == NULL) { 340 if (!(dev->si_flags & SI_NAMED)) 341 make_dev(&snp_cdevsw, minor(dev), UID_ROOT, GID_WHEEL, 342 0600, "snp%d", dev2unit(dev)); 343 dev->si_drv1 = snp = malloc(sizeof(*snp), M_SNP, 344 M_WAITOK | M_ZERO); 345 } else 346 return (EBUSY); 347 348 /* 349 * We intentionally do not OR flags with SNOOP_OPEN, but set them so 350 * all previous settings (especially SNOOP_OFLOW) will be cleared. 351 */ 352 snp->snp_flags = SNOOP_OPEN; 353 354 snp->snp_buf = malloc(SNOOP_MINLEN, M_SNP, M_WAITOK); 355 snp->snp_blen = SNOOP_MINLEN; 356 snp->snp_base = 0; 357 snp->snp_len = 0; 358 359 /* 360 * snp_tty == NULL is for inactive snoop devices. 361 */ 362 snp->snp_tty = NULL; 363 snp->snp_target = NODEV; 364 return (0); 365 } 366 367 368 static int 369 snp_detach(snp) 370 struct snoop *snp; 371 { 372 struct tty *tp; 373 374 snp->snp_base = 0; 375 snp->snp_len = 0; 376 377 /* 378 * If line disc. changed we do not touch this pointer, SLIP/PPP will 379 * change it anyway. 380 */ 381 tp = snp->snp_tty; 382 if (tp == NULL) 383 goto detach_notty; 384 385 if (tp && (tp->t_sc == snp) && (tp->t_state & TS_SNOOP) && 386 tp->t_line == snooplinedisc) { 387 tp->t_sc = NULL; 388 tp->t_state &= ~TS_SNOOP; 389 tp->t_line = snp->snp_olddisc; 390 } else 391 printf("Snoop: bad attached tty data.\n"); 392 393 snp->snp_tty = NULL; 394 snp->snp_target = NODEV; 395 396 detach_notty: 397 selwakeup(&snp->snp_sel); 398 snp->snp_sel.si_pid = 0; 399 if ((snp->snp_flags & SNOOP_OPEN) == 0) 400 free(snp, M_SNP); 401 402 return (0); 403 } 404 405 static int 406 snpclose(dev, flags, fmt, p) 407 dev_t dev; 408 int flags; 409 int fmt; 410 struct proc *p; 411 { 412 struct snoop *snp; 413 414 snp = dev->si_drv1; 415 snp->snp_blen = 0; 416 free(snp->snp_buf, M_SNP); 417 snp->snp_flags &= ~SNOOP_OPEN; 418 dev->si_drv1 = NULL; 419 destroy_dev(dev); 420 421 return (snp_detach(snp)); 422 } 423 424 static int 425 snp_down(snp) 426 struct snoop *snp; 427 { 428 429 if (snp->snp_blen != SNOOP_MINLEN) { 430 free(snp->snp_buf, M_SNP); 431 snp->snp_buf = malloc(SNOOP_MINLEN, M_SNP, M_WAITOK); 432 snp->snp_blen = SNOOP_MINLEN; 433 } 434 snp->snp_flags |= SNOOP_DOWN; 435 436 return (snp_detach(snp)); 437 } 438 439 static int 440 snpioctl(dev, cmd, data, flags, p) 441 dev_t dev; 442 u_long cmd; 443 caddr_t data; 444 int flags; 445 struct proc *p; 446 { 447 struct snoop *snp; 448 struct tty *tp, *tpo; 449 dev_t tdev; 450 int s; 451 452 snp = dev->si_drv1; 453 switch (cmd) { 454 case SNPSTTY: 455 tdev = udev2dev(*((udev_t *)data), 0); 456 if (tdev == NODEV) 457 return (snp_down(snp)); 458 459 tp = snpdevtotty(tdev); 460 if (!tp) 461 return (EINVAL); 462 463 s = spltty(); 464 465 if (snp->snp_target == NODEV) { 466 tpo = snp->snp_tty; 467 if (tpo) 468 tpo->t_state &= ~TS_SNOOP; 469 } 470 471 tp->t_sc = (caddr_t)snp; 472 tp->t_state |= TS_SNOOP; 473 snp->snp_olddisc = tp->t_line; 474 tp->t_line = snooplinedisc; 475 snp->snp_tty = tp; 476 snp->snp_target = tdev; 477 478 /* 479 * Clean overflow and down flags - 480 * we'll have a chance to get them in the future :))) 481 */ 482 snp->snp_flags &= ~SNOOP_OFLOW; 483 snp->snp_flags &= ~SNOOP_DOWN; 484 splx(s); 485 break; 486 487 case SNPGTTY: 488 /* 489 * We keep snp_target field specially to make 490 * SNPGTTY happy, else we can't know what is device 491 * major/minor for tty. 492 */ 493 *((dev_t *)data) = snp->snp_target; 494 break; 495 496 case FIONBIO: 497 break; 498 499 case FIOASYNC: 500 if (*(int *)data) 501 snp->snp_flags |= SNOOP_ASYNC; 502 else 503 snp->snp_flags &= ~SNOOP_ASYNC; 504 break; 505 506 case FIONREAD: 507 s = spltty(); 508 if (snp->snp_tty != NULL) 509 *(int *)data = snp->snp_len; 510 else 511 if (snp->snp_flags & SNOOP_DOWN) { 512 if (snp->snp_flags & SNOOP_OFLOW) 513 *(int *)data = SNP_OFLOW; 514 else 515 *(int *)data = SNP_TTYCLOSE; 516 } else { 517 *(int *)data = SNP_DETACH; 518 } 519 splx(s); 520 break; 521 522 default: 523 return (ENOTTY); 524 } 525 return (0); 526 } 527 528 static int 529 snppoll(dev, events, p) 530 dev_t dev; 531 int events; 532 struct proc *p; 533 { 534 struct snoop *snp; 535 int revents; 536 537 snp = dev->si_drv1; 538 revents = 0; 539 /* 540 * If snoop is down, we don't want to poll() forever so we return 1. 541 * Caller should see if we down via FIONREAD ioctl(). The last should 542 * return -1 to indicate down state. 543 */ 544 if (events & (POLLIN | POLLRDNORM)) { 545 if (snp->snp_flags & SNOOP_DOWN || snp->snp_len > 0) 546 revents |= events & (POLLIN | POLLRDNORM); 547 else 548 selrecord(p, &snp->snp_sel); 549 } 550 return (revents); 551 } 552 553 static void 554 snp_clone(arg, name, namelen, dev) 555 void *arg; 556 char *name; 557 int namelen; 558 dev_t *dev; 559 { 560 int u; 561 562 if (*dev != NODEV) 563 return; 564 if (dev_stdclone(name, NULL, "snp", &u) != 1) 565 return; 566 *dev = make_dev(&snp_cdevsw, unit2minor(u), UID_ROOT, GID_WHEEL, 0600, 567 "snp%d", u); 568 } 569 570 static int 571 snp_modevent(mod, type, data) 572 module_t mod; 573 int type; 574 void *data; 575 { 576 static eventhandler_tag eh_tag; 577 578 switch (type) { 579 case MOD_LOAD: 580 /* XXX error checking. */ 581 eh_tag = EVENTHANDLER_REGISTER(dev_clone, snp_clone, 0, 1000); 582 snooplinedisc = ldisc_register(LDISC_LOAD, &snpdisc); 583 cdevsw_add(&snp_cdevsw); 584 break; 585 case MOD_UNLOAD: 586 /* XXX don't unload if busy. */ 587 EVENTHANDLER_DEREGISTER(dev_clone, eh_tag); 588 ldisc_deregister(snooplinedisc); 589 cdevsw_remove(&snp_cdevsw); 590 break; 591 default: 592 break; 593 } 594 return (0); 595 } 596 597 static moduledata_t snp_mod = { 598 "snp", 599 snp_modevent, 600 NULL 601 }; 602 DECLARE_MODULE(snp, snp_mod, SI_SUB_DRIVERS, SI_ORDER_MIDDLE + CDEV_MAJOR); 603