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/queue.h> 27 #include <sys/snoop.h> 28 #include <sys/vnode.h> 29 30 static l_close_t snplclose; 31 static l_write_t snplwrite; 32 static d_open_t snpopen; 33 static d_close_t snpclose; 34 static d_read_t snpread; 35 static d_write_t snpwrite; 36 static d_ioctl_t snpioctl; 37 static d_poll_t snppoll; 38 39 #define CDEV_MAJOR 53 40 static struct cdevsw snp_cdevsw = { 41 /* open */ snpopen, 42 /* close */ snpclose, 43 /* read */ snpread, 44 /* write */ snpwrite, 45 /* ioctl */ snpioctl, 46 /* poll */ snppoll, 47 /* mmap */ nommap, 48 /* strategy */ nostrategy, 49 /* name */ "snp", 50 /* maj */ CDEV_MAJOR, 51 /* dump */ nodump, 52 /* psize */ nopsize, 53 /* flags */ 0, 54 }; 55 56 static struct linesw snpdisc = { 57 ttyopen, snplclose, ttread, snplwrite, 58 l_nullioctl, ttyinput, ttstart, ttymodem 59 }; 60 61 /* 62 * This is the main snoop per-device structure. 63 */ 64 struct snoop { 65 LIST_ENTRY(snoop) snp_list; /* List glue. */ 66 int snp_unit; /* Device number. */ 67 dev_t snp_target; /* Target tty device. */ 68 struct tty *snp_tty; /* Target tty pointer. */ 69 u_long snp_len; /* Possible length. */ 70 u_long snp_base; /* Data base. */ 71 u_long snp_blen; /* Used length. */ 72 caddr_t snp_buf; /* Allocation pointer. */ 73 int snp_flags; /* Flags. */ 74 struct selinfo snp_sel; /* Select info. */ 75 int snp_olddisc; /* Old line discipline. */ 76 }; 77 78 /* 79 * Possible flags. 80 */ 81 #define SNOOP_ASYNC 0x0002 82 #define SNOOP_OPEN 0x0004 83 #define SNOOP_RWAIT 0x0008 84 #define SNOOP_OFLOW 0x0010 85 #define SNOOP_DOWN 0x0020 86 87 /* 88 * Other constants. 89 */ 90 #define SNOOP_MINLEN (4*1024) /* This should be power of 2. 91 * 4K tested to be the minimum 92 * for which on normal tty 93 * usage there is no need to 94 * allocate more. 95 */ 96 #define SNOOP_MAXLEN (64*1024) /* This one also,64K enough 97 * If we grow more,something 98 * really bad in this world.. 99 */ 100 101 static MALLOC_DEFINE(M_SNP, "snp", "Snoop device data"); 102 /* 103 * The number of the "snoop" line discipline. This gets determined at 104 * module load time. 105 */ 106 static int snooplinedisc; 107 static udev_t snpbasedev = NOUDEV; 108 109 110 static LIST_HEAD(, snoop) snp_sclist = LIST_HEAD_INITIALIZER(&snp_sclist); 111 112 static struct tty *snpdevtotty(dev_t dev); 113 static void snp_clone(void *arg, char *name, 114 int namelen, dev_t *dev); 115 static int snp_detach(struct snoop *snp); 116 static int snp_down(struct snoop *snp); 117 static int snp_in(struct snoop *snp, char *buf, int n); 118 static int snp_modevent(module_t mod, int what, void *arg); 119 120 static int 121 snplclose(tp, flag) 122 struct tty *tp; 123 int flag; 124 { 125 struct snoop *snp; 126 int error; 127 128 snp = tp->t_sc; 129 error = snp_down(snp); 130 if (error != 0) 131 return (error); 132 error = ttylclose(tp, flag); 133 return (error); 134 } 135 136 static int 137 snplwrite(tp, uio, flag) 138 struct tty *tp; 139 struct uio *uio; 140 int flag; 141 { 142 struct iovec iov; 143 struct uio uio2; 144 struct snoop *snp; 145 int error, ilen; 146 char *ibuf; 147 148 error = 0; 149 ibuf = NULL; 150 snp = tp->t_sc; 151 while (uio->uio_resid > 0) { 152 ilen = imin(512, uio->uio_resid); 153 ibuf = malloc(ilen, M_SNP, M_WAITOK); 154 error = uiomove(ibuf, ilen, uio); 155 if (error != 0) 156 break; 157 snp_in(snp, ibuf, ilen); 158 /* Hackish, but probably the least of all evils. */ 159 iov.iov_base = ibuf; 160 iov.iov_len = ilen; 161 uio2.uio_iov = &iov; 162 uio2.uio_iovcnt = 1; 163 uio2.uio_offset = 0; 164 uio2.uio_resid = ilen; 165 uio2.uio_segflg = UIO_SYSSPACE; 166 uio2.uio_rw = UIO_WRITE; 167 uio2.uio_td = uio->uio_td; 168 error = ttwrite(tp, &uio2, flag); 169 if (error != 0) 170 break; 171 free(ibuf, M_SNP); 172 ibuf = NULL; 173 } 174 if (ibuf != NULL) 175 free(ibuf, M_SNP); 176 return (error); 177 } 178 179 static struct tty * 180 snpdevtotty(dev) 181 dev_t dev; 182 { 183 struct cdevsw *cdp; 184 185 cdp = devsw(dev); 186 if (cdp == NULL || (cdp->d_flags & D_TTY) == 0) 187 return (NULL); 188 return (dev->si_tty); 189 } 190 191 #define SNP_INPUT_BUF 5 /* This is even too much, the maximal 192 * interactive mode write is 3 bytes 193 * length for function keys... 194 */ 195 196 static int 197 snpwrite(dev, uio, flag) 198 dev_t dev; 199 struct uio *uio; 200 int flag; 201 { 202 struct snoop *snp; 203 struct tty *tp; 204 int error, i, len; 205 unsigned char c[SNP_INPUT_BUF]; 206 207 snp = dev->si_drv1; 208 tp = snp->snp_tty; 209 if (tp == NULL) 210 return (EIO); 211 if ((tp->t_sc == snp) && (tp->t_state & TS_SNOOP) && 212 tp->t_line == snooplinedisc) 213 goto tty_input; 214 215 printf("snp%d: attempt to write to bad tty\n", snp->snp_unit); 216 return (EIO); 217 218 tty_input: 219 if (!(tp->t_state & TS_ISOPEN)) 220 return (EIO); 221 222 while (uio->uio_resid > 0) { 223 len = imin(uio->uio_resid, SNP_INPUT_BUF); 224 if ((error = uiomove(c, len, uio)) != 0) 225 return (error); 226 for (i=0; i < len; i++) { 227 if (ttyinput(c[i], tp)) 228 return (EIO); 229 } 230 } 231 return (0); 232 } 233 234 235 static int 236 snpread(dev, uio, flag) 237 dev_t dev; 238 struct uio *uio; 239 int flag; 240 { 241 struct snoop *snp; 242 int error, len, n, nblen, s; 243 caddr_t from; 244 char *nbuf; 245 246 snp = dev->si_drv1; 247 KASSERT(snp->snp_len + snp->snp_base <= snp->snp_blen, 248 ("snoop buffer error")); 249 250 if (snp->snp_tty == NULL) 251 return (EIO); 252 253 snp->snp_flags &= ~SNOOP_RWAIT; 254 255 do { 256 if (snp->snp_len == 0) { 257 if (flag & IO_NDELAY) 258 return (EWOULDBLOCK); 259 snp->snp_flags |= SNOOP_RWAIT; 260 error = tsleep((caddr_t)snp, (PZERO + 1) | PCATCH, 261 "snprd", 0); 262 if (error != 0) 263 return (error); 264 } 265 } while (snp->snp_len == 0); 266 267 n = snp->snp_len; 268 269 error = 0; 270 while (snp->snp_len > 0 && uio->uio_resid > 0 && error == 0) { 271 len = min((unsigned)uio->uio_resid, snp->snp_len); 272 from = (caddr_t)(snp->snp_buf + snp->snp_base); 273 if (len == 0) 274 break; 275 276 error = uiomove(from, len, uio); 277 snp->snp_base += len; 278 snp->snp_len -= len; 279 } 280 if ((snp->snp_flags & SNOOP_OFLOW) && (n < snp->snp_len)) { 281 snp->snp_flags &= ~SNOOP_OFLOW; 282 } 283 s = spltty(); 284 nblen = snp->snp_blen; 285 if (((nblen / 2) >= SNOOP_MINLEN) && (nblen / 2) >= snp->snp_len) { 286 while (nblen / 2 >= snp->snp_len && nblen / 2 >= SNOOP_MINLEN) 287 nblen = nblen / 2; 288 if ((nbuf = malloc(nblen, M_SNP, M_NOWAIT)) != NULL) { 289 bcopy(snp->snp_buf + snp->snp_base, nbuf, snp->snp_len); 290 free(snp->snp_buf, M_SNP); 291 snp->snp_buf = nbuf; 292 snp->snp_blen = nblen; 293 snp->snp_base = 0; 294 } 295 } 296 splx(s); 297 298 return (error); 299 } 300 301 static int 302 snp_in(snp, buf, n) 303 struct snoop *snp; 304 char *buf; 305 int n; 306 { 307 int s_free, s_tail; 308 int s, len, nblen; 309 caddr_t from, to; 310 char *nbuf; 311 312 KASSERT(n >= 0, ("negative snoop char count")); 313 314 if (n == 0) 315 return (0); 316 317 if (snp->snp_flags & SNOOP_DOWN) { 318 printf("snp%d: more data to down interface\n", snp->snp_unit); 319 return (0); 320 } 321 322 if (snp->snp_flags & SNOOP_OFLOW) { 323 printf("snp%d: buffer overflow\n", snp->snp_unit); 324 /* 325 * On overflow we just repeat the standart close 326 * procedure...yes , this is waste of space but.. Then next 327 * read from device will fail if one would recall he is 328 * snooping and retry... 329 */ 330 331 return (snp_down(snp)); 332 } 333 s_tail = snp->snp_blen - (snp->snp_len + snp->snp_base); 334 s_free = snp->snp_blen - snp->snp_len; 335 336 337 if (n > s_free) { 338 s = spltty(); 339 nblen = snp->snp_blen; 340 while ((n > s_free) && ((nblen * 2) <= SNOOP_MAXLEN)) { 341 nblen = snp->snp_blen * 2; 342 s_free = nblen - (snp->snp_len + snp->snp_base); 343 } 344 if ((n <= s_free) && (nbuf = malloc(nblen, M_SNP, M_NOWAIT))) { 345 bcopy(snp->snp_buf + snp->snp_base, nbuf, snp->snp_len); 346 free(snp->snp_buf, M_SNP); 347 snp->snp_buf = nbuf; 348 snp->snp_blen = nblen; 349 snp->snp_base = 0; 350 } else { 351 snp->snp_flags |= SNOOP_OFLOW; 352 if (snp->snp_flags & SNOOP_RWAIT) { 353 snp->snp_flags &= ~SNOOP_RWAIT; 354 wakeup((caddr_t)snp); 355 } 356 splx(s); 357 return (0); 358 } 359 splx(s); 360 } 361 if (n > s_tail) { 362 from = (caddr_t)(snp->snp_buf + snp->snp_base); 363 to = (caddr_t)(snp->snp_buf); 364 len = snp->snp_len; 365 bcopy(from, to, len); 366 snp->snp_base = 0; 367 } 368 to = (caddr_t)(snp->snp_buf + snp->snp_base + snp->snp_len); 369 bcopy(buf, to, n); 370 snp->snp_len += n; 371 372 if (snp->snp_flags & SNOOP_RWAIT) { 373 snp->snp_flags &= ~SNOOP_RWAIT; 374 wakeup((caddr_t)snp); 375 } 376 selwakeup(&snp->snp_sel); 377 378 return (n); 379 } 380 381 static int 382 snpopen(dev, flag, mode, td) 383 dev_t dev; 384 int flag, mode; 385 struct thread *td; 386 { 387 struct snoop *snp; 388 389 if (dev->si_drv1 == NULL) { 390 if (!(dev->si_flags & SI_NAMED)) 391 make_dev(&snp_cdevsw, minor(dev), UID_ROOT, GID_WHEEL, 392 0600, "snp%d", dev2unit(dev)); 393 dev->si_drv1 = snp = malloc(sizeof(*snp), M_SNP, 394 M_WAITOK | M_ZERO); 395 snp->snp_unit = dev2unit(dev); 396 } else 397 return (EBUSY); 398 399 /* 400 * We intentionally do not OR flags with SNOOP_OPEN, but set them so 401 * all previous settings (especially SNOOP_OFLOW) will be cleared. 402 */ 403 snp->snp_flags = SNOOP_OPEN; 404 405 snp->snp_buf = malloc(SNOOP_MINLEN, M_SNP, M_WAITOK); 406 snp->snp_blen = SNOOP_MINLEN; 407 snp->snp_base = 0; 408 snp->snp_len = 0; 409 410 /* 411 * snp_tty == NULL is for inactive snoop devices. 412 */ 413 snp->snp_tty = NULL; 414 snp->snp_target = NODEV; 415 416 LIST_INSERT_HEAD(&snp_sclist, snp, snp_list); 417 return (0); 418 } 419 420 421 static int 422 snp_detach(snp) 423 struct snoop *snp; 424 { 425 struct tty *tp; 426 427 snp->snp_base = 0; 428 snp->snp_len = 0; 429 430 /* 431 * If line disc. changed we do not touch this pointer, SLIP/PPP will 432 * change it anyway. 433 */ 434 tp = snp->snp_tty; 435 if (tp == NULL) 436 goto detach_notty; 437 438 if (tp && (tp->t_sc == snp) && (tp->t_state & TS_SNOOP) && 439 tp->t_line == snooplinedisc) { 440 tp->t_sc = NULL; 441 tp->t_state &= ~TS_SNOOP; 442 tp->t_line = snp->snp_olddisc; 443 } else 444 printf("snp%d: bad attached tty data\n", snp->snp_unit); 445 446 snp->snp_tty = NULL; 447 snp->snp_target = NODEV; 448 449 detach_notty: 450 selwakeup(&snp->snp_sel); 451 if ((snp->snp_flags & SNOOP_OPEN) == 0) 452 free(snp, M_SNP); 453 454 return (0); 455 } 456 457 static int 458 snpclose(dev, flags, fmt, td) 459 dev_t dev; 460 int flags; 461 int fmt; 462 struct thread *td; 463 { 464 struct snoop *snp; 465 466 snp = dev->si_drv1; 467 snp->snp_blen = 0; 468 LIST_REMOVE(snp, snp_list); 469 free(snp->snp_buf, M_SNP); 470 snp->snp_flags &= ~SNOOP_OPEN; 471 dev->si_drv1 = NULL; 472 473 return (snp_detach(snp)); 474 } 475 476 static int 477 snp_down(snp) 478 struct snoop *snp; 479 { 480 481 if (snp->snp_blen != SNOOP_MINLEN) { 482 free(snp->snp_buf, M_SNP); 483 snp->snp_buf = malloc(SNOOP_MINLEN, M_SNP, M_WAITOK); 484 snp->snp_blen = SNOOP_MINLEN; 485 } 486 snp->snp_flags |= SNOOP_DOWN; 487 488 return (snp_detach(snp)); 489 } 490 491 static int 492 snpioctl(dev, cmd, data, flags, td) 493 dev_t dev; 494 u_long cmd; 495 caddr_t data; 496 int flags; 497 struct thread *td; 498 { 499 struct snoop *snp; 500 struct tty *tp, *tpo; 501 dev_t tdev; 502 int s; 503 504 snp = dev->si_drv1; 505 switch (cmd) { 506 case SNPSTTY: 507 tdev = udev2dev(*((udev_t *)data), 0); 508 if (tdev == NODEV) 509 return (snp_down(snp)); 510 511 tp = snpdevtotty(tdev); 512 if (!tp) 513 return (EINVAL); 514 if (tp->t_state & TS_SNOOP) 515 return (EBUSY); 516 517 s = spltty(); 518 519 if (snp->snp_target == NODEV) { 520 tpo = snp->snp_tty; 521 if (tpo) 522 tpo->t_state &= ~TS_SNOOP; 523 } 524 525 tp->t_sc = (caddr_t)snp; 526 tp->t_state |= TS_SNOOP; 527 snp->snp_olddisc = tp->t_line; 528 tp->t_line = snooplinedisc; 529 snp->snp_tty = tp; 530 snp->snp_target = tdev; 531 532 /* 533 * Clean overflow and down flags - 534 * we'll have a chance to get them in the future :))) 535 */ 536 snp->snp_flags &= ~SNOOP_OFLOW; 537 snp->snp_flags &= ~SNOOP_DOWN; 538 splx(s); 539 break; 540 541 case SNPGTTY: 542 /* 543 * We keep snp_target field specially to make 544 * SNPGTTY happy, else we can't know what is device 545 * major/minor for tty. 546 */ 547 *((dev_t *)data) = snp->snp_target; 548 break; 549 550 case FIONBIO: 551 break; 552 553 case FIOASYNC: 554 if (*(int *)data) 555 snp->snp_flags |= SNOOP_ASYNC; 556 else 557 snp->snp_flags &= ~SNOOP_ASYNC; 558 break; 559 560 case FIONREAD: 561 s = spltty(); 562 if (snp->snp_tty != NULL) 563 *(int *)data = snp->snp_len; 564 else 565 if (snp->snp_flags & SNOOP_DOWN) { 566 if (snp->snp_flags & SNOOP_OFLOW) 567 *(int *)data = SNP_OFLOW; 568 else 569 *(int *)data = SNP_TTYCLOSE; 570 } else { 571 *(int *)data = SNP_DETACH; 572 } 573 splx(s); 574 break; 575 576 default: 577 return (ENOTTY); 578 } 579 return (0); 580 } 581 582 static int 583 snppoll(dev, events, td) 584 dev_t dev; 585 int events; 586 struct thread *td; 587 { 588 struct snoop *snp; 589 int revents; 590 591 snp = dev->si_drv1; 592 revents = 0; 593 /* 594 * If snoop is down, we don't want to poll() forever so we return 1. 595 * Caller should see if we down via FIONREAD ioctl(). The last should 596 * return -1 to indicate down state. 597 */ 598 if (events & (POLLIN | POLLRDNORM)) { 599 if (snp->snp_flags & SNOOP_DOWN || snp->snp_len > 0) 600 revents |= events & (POLLIN | POLLRDNORM); 601 else 602 selrecord(td, &snp->snp_sel); 603 } 604 return (revents); 605 } 606 607 static void 608 snp_clone(arg, name, namelen, dev) 609 void *arg; 610 char *name; 611 int namelen; 612 dev_t *dev; 613 { 614 int u; 615 616 if (*dev != NODEV) 617 return; 618 if (dev_stdclone(name, NULL, "snp", &u) != 1) 619 return; 620 *dev = make_dev(&snp_cdevsw, unit2minor(u), UID_ROOT, GID_WHEEL, 0600, 621 "snp%d", u); 622 if (snpbasedev == NOUDEV) 623 snpbasedev = (*dev)->si_udev; 624 else { 625 (*dev)->si_flags |= SI_CHEAPCLONE; 626 dev_depends(udev2dev(snpbasedev, 0), *dev); 627 } 628 } 629 630 static int 631 snp_modevent(mod, type, data) 632 module_t mod; 633 int type; 634 void *data; 635 { 636 static eventhandler_tag eh_tag; 637 638 switch (type) { 639 case MOD_LOAD: 640 /* XXX error checking. */ 641 eh_tag = EVENTHANDLER_REGISTER(dev_clone, snp_clone, 0, 1000); 642 snooplinedisc = ldisc_register(LDISC_LOAD, &snpdisc); 643 cdevsw_add(&snp_cdevsw); 644 break; 645 case MOD_UNLOAD: 646 if (!LIST_EMPTY(&snp_sclist)) 647 return (EBUSY); 648 EVENTHANDLER_DEREGISTER(dev_clone, eh_tag); 649 if (snpbasedev != NOUDEV) 650 destroy_dev(udev2dev(snpbasedev, 0)); 651 ldisc_deregister(snooplinedisc); 652 cdevsw_remove(&snp_cdevsw); 653 break; 654 default: 655 break; 656 } 657 return (0); 658 } 659 660 static moduledata_t snp_mod = { 661 "snp", 662 snp_modevent, 663 NULL 664 }; 665 DECLARE_MODULE(snp, snp_mod, SI_SUB_DRIVERS, SI_ORDER_MIDDLE + CDEV_MAJOR); 666