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 */ 16 17 #include <sys/cdefs.h> 18 __FBSDID("$FreeBSD$"); 19 20 #include <sys/param.h> 21 #include <sys/systm.h> 22 #include <sys/filio.h> 23 #include <sys/malloc.h> 24 #include <sys/tty.h> 25 #include <sys/conf.h> 26 #include <sys/poll.h> 27 #include <sys/kernel.h> 28 #include <sys/queue.h> 29 #include <sys/snoop.h> 30 #include <sys/vnode.h> 31 32 static l_close_t snplclose; 33 static l_write_t snplwrite; 34 static d_open_t snpopen; 35 static d_close_t snpclose; 36 static d_read_t snpread; 37 static d_write_t snpwrite; 38 static d_ioctl_t snpioctl; 39 static d_poll_t snppoll; 40 41 #define CDEV_MAJOR 53 42 static struct cdevsw snp_cdevsw = { 43 .d_open = snpopen, 44 .d_close = snpclose, 45 .d_read = snpread, 46 .d_write = snpwrite, 47 .d_ioctl = snpioctl, 48 .d_poll = snppoll, 49 .d_name = "snp", 50 .d_maj = CDEV_MAJOR, 51 }; 52 53 static struct linesw snpdisc = { 54 ttyopen, snplclose, ttread, snplwrite, 55 l_nullioctl, ttyinput, ttstart, ttymodem 56 }; 57 58 /* 59 * This is the main snoop per-device structure. 60 */ 61 struct snoop { 62 LIST_ENTRY(snoop) snp_list; /* List glue. */ 63 int snp_unit; /* Device number. */ 64 dev_t snp_target; /* Target tty device. */ 65 struct tty *snp_tty; /* Target tty pointer. */ 66 u_long snp_len; /* Possible length. */ 67 u_long snp_base; /* Data base. */ 68 u_long snp_blen; /* Used length. */ 69 caddr_t snp_buf; /* Allocation pointer. */ 70 int snp_flags; /* Flags. */ 71 struct selinfo snp_sel; /* Select info. */ 72 int snp_olddisc; /* Old line discipline. */ 73 }; 74 75 /* 76 * Possible flags. 77 */ 78 #define SNOOP_ASYNC 0x0002 79 #define SNOOP_OPEN 0x0004 80 #define SNOOP_RWAIT 0x0008 81 #define SNOOP_OFLOW 0x0010 82 #define SNOOP_DOWN 0x0020 83 84 /* 85 * Other constants. 86 */ 87 #define SNOOP_MINLEN (4*1024) /* This should be power of 2. 88 * 4K tested to be the minimum 89 * for which on normal tty 90 * usage there is no need to 91 * allocate more. 92 */ 93 #define SNOOP_MAXLEN (64*1024) /* This one also,64K enough 94 * If we grow more,something 95 * really bad in this world.. 96 */ 97 98 static MALLOC_DEFINE(M_SNP, "snp", "Snoop device data"); 99 /* 100 * The number of the "snoop" line discipline. This gets determined at 101 * module load time. 102 */ 103 static int snooplinedisc; 104 static udev_t snpbasedev = NOUDEV; 105 106 107 static LIST_HEAD(, snoop) snp_sclist = LIST_HEAD_INITIALIZER(&snp_sclist); 108 109 static struct tty *snpdevtotty(dev_t dev); 110 static void snp_clone(void *arg, char *name, 111 int namelen, dev_t *dev); 112 static int snp_detach(struct snoop *snp); 113 static int snp_down(struct snoop *snp); 114 static int snp_in(struct snoop *snp, char *buf, int n); 115 static int snp_modevent(module_t mod, int what, void *arg); 116 117 static int 118 snplclose(tp, flag) 119 struct tty *tp; 120 int flag; 121 { 122 struct snoop *snp; 123 int error; 124 125 snp = tp->t_sc; 126 error = snp_down(snp); 127 if (error != 0) 128 return (error); 129 error = ttylclose(tp, flag); 130 return (error); 131 } 132 133 static int 134 snplwrite(tp, uio, flag) 135 struct tty *tp; 136 struct uio *uio; 137 int flag; 138 { 139 struct iovec iov; 140 struct uio uio2; 141 struct snoop *snp; 142 int error, ilen; 143 char *ibuf; 144 145 error = 0; 146 ibuf = NULL; 147 snp = tp->t_sc; 148 while (uio->uio_resid > 0) { 149 ilen = imin(512, uio->uio_resid); 150 ibuf = malloc(ilen, M_SNP, M_WAITOK); 151 error = uiomove(ibuf, ilen, uio); 152 if (error != 0) 153 break; 154 snp_in(snp, ibuf, ilen); 155 /* Hackish, but probably the least of all evils. */ 156 iov.iov_base = ibuf; 157 iov.iov_len = ilen; 158 uio2.uio_iov = &iov; 159 uio2.uio_iovcnt = 1; 160 uio2.uio_offset = 0; 161 uio2.uio_resid = ilen; 162 uio2.uio_segflg = UIO_SYSSPACE; 163 uio2.uio_rw = UIO_WRITE; 164 uio2.uio_td = uio->uio_td; 165 error = ttwrite(tp, &uio2, flag); 166 if (error != 0) 167 break; 168 free(ibuf, M_SNP); 169 ibuf = NULL; 170 } 171 if (ibuf != NULL) 172 free(ibuf, M_SNP); 173 return (error); 174 } 175 176 static struct tty * 177 snpdevtotty(dev) 178 dev_t dev; 179 { 180 struct cdevsw *cdp; 181 182 cdp = devsw(dev); 183 if (cdp == NULL || (cdp->d_flags & D_TTY) == 0) 184 return (NULL); 185 return (dev->si_tty); 186 } 187 188 #define SNP_INPUT_BUF 5 /* This is even too much, the maximal 189 * interactive mode write is 3 bytes 190 * length for function keys... 191 */ 192 193 static int 194 snpwrite(dev, uio, flag) 195 dev_t dev; 196 struct uio *uio; 197 int flag; 198 { 199 struct snoop *snp; 200 struct tty *tp; 201 int error, i, len; 202 unsigned char c[SNP_INPUT_BUF]; 203 204 snp = dev->si_drv1; 205 tp = snp->snp_tty; 206 if (tp == NULL) 207 return (EIO); 208 if ((tp->t_sc == snp) && (tp->t_state & TS_SNOOP) && 209 tp->t_line == snooplinedisc) 210 goto tty_input; 211 212 printf("snp%d: attempt to write to bad tty\n", snp->snp_unit); 213 return (EIO); 214 215 tty_input: 216 if (!(tp->t_state & TS_ISOPEN)) 217 return (EIO); 218 219 while (uio->uio_resid > 0) { 220 len = imin(uio->uio_resid, SNP_INPUT_BUF); 221 if ((error = uiomove(c, len, uio)) != 0) 222 return (error); 223 for (i=0; i < len; i++) { 224 if (ttyinput(c[i], tp)) 225 return (EIO); 226 } 227 } 228 return (0); 229 } 230 231 232 static int 233 snpread(dev, uio, flag) 234 dev_t dev; 235 struct uio *uio; 236 int flag; 237 { 238 struct snoop *snp; 239 int error, len, n, nblen, s; 240 caddr_t from; 241 char *nbuf; 242 243 snp = dev->si_drv1; 244 KASSERT(snp->snp_len + snp->snp_base <= snp->snp_blen, 245 ("snoop buffer error")); 246 247 if (snp->snp_tty == NULL) 248 return (EIO); 249 250 snp->snp_flags &= ~SNOOP_RWAIT; 251 252 do { 253 if (snp->snp_len == 0) { 254 if (flag & IO_NDELAY) 255 return (EWOULDBLOCK); 256 snp->snp_flags |= SNOOP_RWAIT; 257 error = tsleep(snp, (PZERO + 1) | PCATCH, 258 "snprd", 0); 259 if (error != 0) 260 return (error); 261 } 262 } while (snp->snp_len == 0); 263 264 n = snp->snp_len; 265 266 error = 0; 267 while (snp->snp_len > 0 && uio->uio_resid > 0 && error == 0) { 268 len = min((unsigned)uio->uio_resid, snp->snp_len); 269 from = (caddr_t)(snp->snp_buf + snp->snp_base); 270 if (len == 0) 271 break; 272 273 error = uiomove(from, len, uio); 274 snp->snp_base += len; 275 snp->snp_len -= len; 276 } 277 if ((snp->snp_flags & SNOOP_OFLOW) && (n < snp->snp_len)) { 278 snp->snp_flags &= ~SNOOP_OFLOW; 279 } 280 s = spltty(); 281 nblen = snp->snp_blen; 282 if (((nblen / 2) >= SNOOP_MINLEN) && (nblen / 2) >= snp->snp_len) { 283 while (nblen / 2 >= snp->snp_len && nblen / 2 >= SNOOP_MINLEN) 284 nblen = nblen / 2; 285 if ((nbuf = malloc(nblen, M_SNP, M_NOWAIT)) != NULL) { 286 bcopy(snp->snp_buf + snp->snp_base, nbuf, snp->snp_len); 287 free(snp->snp_buf, M_SNP); 288 snp->snp_buf = nbuf; 289 snp->snp_blen = nblen; 290 snp->snp_base = 0; 291 } 292 } 293 splx(s); 294 295 return (error); 296 } 297 298 static int 299 snp_in(snp, buf, n) 300 struct snoop *snp; 301 char *buf; 302 int n; 303 { 304 int s_free, s_tail; 305 int s, len, nblen; 306 caddr_t from, to; 307 char *nbuf; 308 309 KASSERT(n >= 0, ("negative snoop char count")); 310 311 if (n == 0) 312 return (0); 313 314 if (snp->snp_flags & SNOOP_DOWN) { 315 printf("snp%d: more data to down interface\n", snp->snp_unit); 316 return (0); 317 } 318 319 if (snp->snp_flags & SNOOP_OFLOW) { 320 printf("snp%d: buffer overflow\n", snp->snp_unit); 321 /* 322 * On overflow we just repeat the standart close 323 * procedure...yes , this is waste of space but.. Then next 324 * read from device will fail if one would recall he is 325 * snooping and retry... 326 */ 327 328 return (snp_down(snp)); 329 } 330 s_tail = snp->snp_blen - (snp->snp_len + snp->snp_base); 331 s_free = snp->snp_blen - snp->snp_len; 332 333 334 if (n > s_free) { 335 s = spltty(); 336 nblen = snp->snp_blen; 337 while ((n > s_free) && ((nblen * 2) <= SNOOP_MAXLEN)) { 338 nblen = snp->snp_blen * 2; 339 s_free = nblen - (snp->snp_len + snp->snp_base); 340 } 341 if ((n <= s_free) && (nbuf = malloc(nblen, M_SNP, M_NOWAIT))) { 342 bcopy(snp->snp_buf + snp->snp_base, nbuf, snp->snp_len); 343 free(snp->snp_buf, M_SNP); 344 snp->snp_buf = nbuf; 345 snp->snp_blen = nblen; 346 snp->snp_base = 0; 347 } else { 348 snp->snp_flags |= SNOOP_OFLOW; 349 if (snp->snp_flags & SNOOP_RWAIT) { 350 snp->snp_flags &= ~SNOOP_RWAIT; 351 wakeup(snp); 352 } 353 splx(s); 354 return (0); 355 } 356 splx(s); 357 } 358 if (n > s_tail) { 359 from = (caddr_t)(snp->snp_buf + snp->snp_base); 360 to = (caddr_t)(snp->snp_buf); 361 len = snp->snp_len; 362 bcopy(from, to, len); 363 snp->snp_base = 0; 364 } 365 to = (caddr_t)(snp->snp_buf + snp->snp_base + snp->snp_len); 366 bcopy(buf, to, n); 367 snp->snp_len += n; 368 369 if (snp->snp_flags & SNOOP_RWAIT) { 370 snp->snp_flags &= ~SNOOP_RWAIT; 371 wakeup(snp); 372 } 373 selwakeup(&snp->snp_sel); 374 375 return (n); 376 } 377 378 static int 379 snpopen(dev, flag, mode, td) 380 dev_t dev; 381 int flag, mode; 382 struct thread *td; 383 { 384 struct snoop *snp; 385 386 if (dev->si_drv1 == NULL) { 387 if (!(dev->si_flags & SI_NAMED)) 388 make_dev(&snp_cdevsw, minor(dev), UID_ROOT, GID_WHEEL, 389 0600, "snp%d", dev2unit(dev)); 390 dev->si_drv1 = snp = malloc(sizeof(*snp), M_SNP, 391 M_WAITOK | M_ZERO); 392 snp->snp_unit = dev2unit(dev); 393 } else 394 return (EBUSY); 395 396 /* 397 * We intentionally do not OR flags with SNOOP_OPEN, but set them so 398 * all previous settings (especially SNOOP_OFLOW) will be cleared. 399 */ 400 snp->snp_flags = SNOOP_OPEN; 401 402 snp->snp_buf = malloc(SNOOP_MINLEN, M_SNP, M_WAITOK); 403 snp->snp_blen = SNOOP_MINLEN; 404 snp->snp_base = 0; 405 snp->snp_len = 0; 406 407 /* 408 * snp_tty == NULL is for inactive snoop devices. 409 */ 410 snp->snp_tty = NULL; 411 snp->snp_target = NODEV; 412 413 LIST_INSERT_HEAD(&snp_sclist, snp, snp_list); 414 return (0); 415 } 416 417 418 static int 419 snp_detach(snp) 420 struct snoop *snp; 421 { 422 struct tty *tp; 423 424 snp->snp_base = 0; 425 snp->snp_len = 0; 426 427 /* 428 * If line disc. changed we do not touch this pointer, SLIP/PPP will 429 * change it anyway. 430 */ 431 tp = snp->snp_tty; 432 if (tp == NULL) 433 goto detach_notty; 434 435 if (tp && (tp->t_sc == snp) && (tp->t_state & TS_SNOOP) && 436 tp->t_line == snooplinedisc) { 437 tp->t_sc = NULL; 438 tp->t_state &= ~TS_SNOOP; 439 tp->t_line = snp->snp_olddisc; 440 } else 441 printf("snp%d: bad attached tty data\n", snp->snp_unit); 442 443 snp->snp_tty = NULL; 444 snp->snp_target = NODEV; 445 446 detach_notty: 447 selwakeup(&snp->snp_sel); 448 if ((snp->snp_flags & SNOOP_OPEN) == 0) 449 free(snp, M_SNP); 450 451 return (0); 452 } 453 454 static int 455 snpclose(dev, flags, fmt, td) 456 dev_t dev; 457 int flags; 458 int fmt; 459 struct thread *td; 460 { 461 struct snoop *snp; 462 463 snp = dev->si_drv1; 464 snp->snp_blen = 0; 465 LIST_REMOVE(snp, snp_list); 466 free(snp->snp_buf, M_SNP); 467 snp->snp_flags &= ~SNOOP_OPEN; 468 dev->si_drv1 = NULL; 469 470 return (snp_detach(snp)); 471 } 472 473 static int 474 snp_down(snp) 475 struct snoop *snp; 476 { 477 478 if (snp->snp_blen != SNOOP_MINLEN) { 479 free(snp->snp_buf, M_SNP); 480 snp->snp_buf = malloc(SNOOP_MINLEN, M_SNP, M_WAITOK); 481 snp->snp_blen = SNOOP_MINLEN; 482 } 483 snp->snp_flags |= SNOOP_DOWN; 484 485 return (snp_detach(snp)); 486 } 487 488 static int 489 snpioctl(dev, cmd, data, flags, td) 490 dev_t dev; 491 u_long cmd; 492 caddr_t data; 493 int flags; 494 struct thread *td; 495 { 496 struct snoop *snp; 497 struct tty *tp, *tpo; 498 dev_t tdev; 499 int s; 500 501 snp = dev->si_drv1; 502 switch (cmd) { 503 case SNPSTTY: 504 tdev = udev2dev(*((udev_t *)data), 0); 505 if (tdev == NODEV) 506 return (snp_down(snp)); 507 508 tp = snpdevtotty(tdev); 509 if (!tp) 510 return (EINVAL); 511 if (tp->t_state & TS_SNOOP) 512 return (EBUSY); 513 514 s = spltty(); 515 516 if (snp->snp_target == NODEV) { 517 tpo = snp->snp_tty; 518 if (tpo) 519 tpo->t_state &= ~TS_SNOOP; 520 } 521 522 tp->t_sc = (caddr_t)snp; 523 tp->t_state |= TS_SNOOP; 524 snp->snp_olddisc = tp->t_line; 525 tp->t_line = snooplinedisc; 526 snp->snp_tty = tp; 527 snp->snp_target = tdev; 528 529 /* 530 * Clean overflow and down flags - 531 * we'll have a chance to get them in the future :))) 532 */ 533 snp->snp_flags &= ~SNOOP_OFLOW; 534 snp->snp_flags &= ~SNOOP_DOWN; 535 splx(s); 536 break; 537 538 case SNPGTTY: 539 /* 540 * We keep snp_target field specially to make 541 * SNPGTTY happy, else we can't know what is device 542 * major/minor for tty. 543 */ 544 *((udev_t *)data) = dev2udev(snp->snp_target); 545 break; 546 547 case FIONBIO: 548 break; 549 550 case FIOASYNC: 551 if (*(int *)data) 552 snp->snp_flags |= SNOOP_ASYNC; 553 else 554 snp->snp_flags &= ~SNOOP_ASYNC; 555 break; 556 557 case FIONREAD: 558 s = spltty(); 559 if (snp->snp_tty != NULL) 560 *(int *)data = snp->snp_len; 561 else 562 if (snp->snp_flags & SNOOP_DOWN) { 563 if (snp->snp_flags & SNOOP_OFLOW) 564 *(int *)data = SNP_OFLOW; 565 else 566 *(int *)data = SNP_TTYCLOSE; 567 } else { 568 *(int *)data = SNP_DETACH; 569 } 570 splx(s); 571 break; 572 573 default: 574 return (ENOTTY); 575 } 576 return (0); 577 } 578 579 static int 580 snppoll(dev, events, td) 581 dev_t dev; 582 int events; 583 struct thread *td; 584 { 585 struct snoop *snp; 586 int revents; 587 588 snp = dev->si_drv1; 589 revents = 0; 590 /* 591 * If snoop is down, we don't want to poll() forever so we return 1. 592 * Caller should see if we down via FIONREAD ioctl(). The last should 593 * return -1 to indicate down state. 594 */ 595 if (events & (POLLIN | POLLRDNORM)) { 596 if (snp->snp_flags & SNOOP_DOWN || snp->snp_len > 0) 597 revents |= events & (POLLIN | POLLRDNORM); 598 else 599 selrecord(td, &snp->snp_sel); 600 } 601 return (revents); 602 } 603 604 static void 605 snp_clone(arg, name, namelen, dev) 606 void *arg; 607 char *name; 608 int namelen; 609 dev_t *dev; 610 { 611 int u; 612 613 if (*dev != NODEV) 614 return; 615 if (dev_stdclone(name, NULL, "snp", &u) != 1) 616 return; 617 *dev = make_dev(&snp_cdevsw, unit2minor(u), UID_ROOT, GID_WHEEL, 0600, 618 "snp%d", u); 619 if (snpbasedev == NOUDEV) 620 snpbasedev = (*dev)->si_udev; 621 else { 622 (*dev)->si_flags |= SI_CHEAPCLONE; 623 dev_depends(udev2dev(snpbasedev, 0), *dev); 624 } 625 } 626 627 static int 628 snp_modevent(mod, type, data) 629 module_t mod; 630 int type; 631 void *data; 632 { 633 static eventhandler_tag eh_tag; 634 635 switch (type) { 636 case MOD_LOAD: 637 /* XXX error checking. */ 638 eh_tag = EVENTHANDLER_REGISTER(dev_clone, snp_clone, 0, 1000); 639 snooplinedisc = ldisc_register(LDISC_LOAD, &snpdisc); 640 break; 641 case MOD_UNLOAD: 642 if (!LIST_EMPTY(&snp_sclist)) 643 return (EBUSY); 644 EVENTHANDLER_DEREGISTER(dev_clone, eh_tag); 645 if (snpbasedev != NOUDEV) 646 destroy_dev(udev2dev(snpbasedev, 0)); 647 ldisc_deregister(snooplinedisc); 648 break; 649 default: 650 break; 651 } 652 return (0); 653 } 654 655 static moduledata_t snp_mod = { 656 "snp", 657 snp_modevent, 658 NULL 659 }; 660 DECLARE_MODULE(snp, snp_mod, SI_SUB_DRIVERS, SI_ORDER_MIDDLE + CDEV_MAJOR); 661