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/fcntl.h> 23 #include <sys/filio.h> 24 #include <sys/malloc.h> 25 #include <sys/tty.h> 26 #include <sys/conf.h> 27 #include <sys/poll.h> 28 #include <sys/kernel.h> 29 #include <sys/module.h> 30 #include <sys/queue.h> 31 #include <sys/snoop.h> 32 #include <sys/uio.h> 33 34 static l_close_t snplclose; 35 static l_write_t snplwrite; 36 static d_open_t snpopen; 37 static d_close_t snpclose; 38 static d_read_t snpread; 39 static d_write_t snpwrite; 40 static d_ioctl_t snpioctl; 41 static d_poll_t snppoll; 42 43 static struct cdevsw snp_cdevsw = { 44 .d_version = D_VERSION, 45 .d_flags = D_PSEUDO | D_NEEDGIANT, 46 .d_open = snpopen, 47 .d_close = snpclose, 48 .d_read = snpread, 49 .d_write = snpwrite, 50 .d_ioctl = snpioctl, 51 .d_poll = snppoll, 52 .d_name = "snp", 53 }; 54 55 static struct linesw snpdisc = { 56 .l_open = tty_open, 57 .l_close = snplclose, 58 .l_read = ttread, 59 .l_write = snplwrite, 60 .l_ioctl = l_nullioctl, 61 .l_rint = ttyinput, 62 .l_start = ttstart, 63 .l_modem = ttymodem 64 }; 65 66 /* 67 * This is the main snoop per-device structure. 68 */ 69 struct snoop { 70 LIST_ENTRY(snoop) snp_list; /* List glue. */ 71 int snp_unit; /* Device number. */ 72 struct cdev *snp_target; /* Target tty device. */ 73 struct tty *snp_tty; /* Target tty pointer. */ 74 u_long snp_len; /* Possible length. */ 75 u_long snp_base; /* Data base. */ 76 u_long snp_blen; /* Used length. */ 77 caddr_t snp_buf; /* Allocation pointer. */ 78 int snp_flags; /* Flags. */ 79 struct selinfo snp_sel; /* Select info. */ 80 int snp_olddisc; /* Old line discipline. */ 81 }; 82 83 /* 84 * Possible flags. 85 */ 86 #define SNOOP_ASYNC 0x0002 87 #define SNOOP_OPEN 0x0004 88 #define SNOOP_RWAIT 0x0008 89 #define SNOOP_OFLOW 0x0010 90 #define SNOOP_DOWN 0x0020 91 92 /* 93 * Other constants. 94 */ 95 #define SNOOP_MINLEN (4*1024) /* This should be power of 2. 96 * 4K tested to be the minimum 97 * for which on normal tty 98 * usage there is no need to 99 * allocate more. 100 */ 101 #define SNOOP_MAXLEN (64*1024) /* This one also,64K enough 102 * If we grow more,something 103 * really bad in this world.. 104 */ 105 106 static MALLOC_DEFINE(M_SNP, "snp", "Snoop device data"); 107 /* 108 * The number of the "snoop" line discipline. This gets determined at 109 * module load time. 110 */ 111 static int snooplinedisc; 112 113 static LIST_HEAD(, snoop) snp_sclist = LIST_HEAD_INITIALIZER(&snp_sclist); 114 static struct clonedevs *snpclones; 115 116 static struct tty *snpdevtotty(struct cdev *dev); 117 static void snp_clone(void *arg, char *name, 118 int namelen, struct cdev **dev); 119 static int snp_detach(struct snoop *snp); 120 static int snp_down(struct snoop *snp); 121 static int snp_in(struct snoop *snp, char *buf, int n); 122 static int snp_modevent(module_t mod, int what, void *arg); 123 static struct snoop *ttytosnp(struct tty *); 124 125 static struct snoop * 126 ttytosnp(struct tty *tp) 127 { 128 struct snoop *snp; 129 130 LIST_FOREACH(snp, &snp_sclist, snp_list) { 131 if (snp->snp_tty == tp) 132 return (snp); 133 } 134 return (NULL); 135 } 136 137 static int 138 snplclose(tp, flag) 139 struct tty *tp; 140 int flag; 141 { 142 struct snoop *snp; 143 int error; 144 145 snp = ttytosnp(tp); 146 error = snp_down(snp); 147 if (error != 0) 148 return (error); 149 error = ttylclose(tp, flag); 150 return (error); 151 } 152 153 static int 154 snplwrite(tp, uio, flag) 155 struct tty *tp; 156 struct uio *uio; 157 int flag; 158 { 159 struct iovec iov; 160 struct uio uio2; 161 struct snoop *snp; 162 int error, ilen; 163 char *ibuf; 164 165 error = 0; 166 ibuf = NULL; 167 snp = ttytosnp(tp); 168 while (uio->uio_resid > 0) { 169 ilen = imin(512, uio->uio_resid); 170 ibuf = malloc(ilen, M_SNP, M_WAITOK); 171 error = uiomove(ibuf, ilen, uio); 172 if (error != 0) 173 break; 174 snp_in(snp, ibuf, ilen); 175 /* Hackish, but probably the least of all evils. */ 176 iov.iov_base = ibuf; 177 iov.iov_len = ilen; 178 uio2.uio_iov = &iov; 179 uio2.uio_iovcnt = 1; 180 uio2.uio_offset = 0; 181 uio2.uio_resid = ilen; 182 uio2.uio_segflg = UIO_SYSSPACE; 183 uio2.uio_rw = UIO_WRITE; 184 uio2.uio_td = uio->uio_td; 185 error = ttwrite(tp, &uio2, flag); 186 if (error != 0) 187 break; 188 free(ibuf, M_SNP); 189 ibuf = NULL; 190 } 191 if (ibuf != NULL) 192 free(ibuf, M_SNP); 193 return (error); 194 } 195 196 static struct tty * 197 snpdevtotty(dev) 198 struct cdev *dev; 199 { 200 struct cdevsw *cdp; 201 struct tty *tp; 202 203 cdp = dev_refthread(dev); 204 if (cdp == NULL) 205 return (NULL); 206 if (!(cdp->d_flags & D_TTY)) 207 tp = NULL; 208 else 209 tp = dev->si_tty; 210 dev_relthread(dev); 211 return (tp); 212 } 213 214 #define SNP_INPUT_BUF 5 /* This is even too much, the maximal 215 * interactive mode write is 3 bytes 216 * length for function keys... 217 */ 218 219 static int 220 snpwrite(dev, uio, flag) 221 struct cdev *dev; 222 struct uio *uio; 223 int flag; 224 { 225 struct snoop *snp; 226 struct tty *tp; 227 int error, i, len; 228 unsigned char c[SNP_INPUT_BUF]; 229 230 snp = dev->si_drv1; 231 tp = snp->snp_tty; 232 if (tp == NULL) 233 return (EIO); 234 if ((tp->t_state & TS_SNOOP) && tp->t_line == snooplinedisc) 235 goto tty_input; 236 237 printf("snp%d: attempt to write to bad tty\n", snp->snp_unit); 238 return (EIO); 239 240 tty_input: 241 if (!(tp->t_state & TS_ISOPEN)) 242 return (EIO); 243 244 while (uio->uio_resid > 0) { 245 len = imin(uio->uio_resid, SNP_INPUT_BUF); 246 if ((error = uiomove(c, len, uio)) != 0) 247 return (error); 248 for (i=0; i < len; i++) { 249 if (ttyinput(c[i], tp)) 250 return (EIO); 251 } 252 } 253 return (0); 254 } 255 256 257 static int 258 snpread(dev, uio, flag) 259 struct cdev *dev; 260 struct uio *uio; 261 int flag; 262 { 263 struct snoop *snp; 264 int error, len, n, nblen, s; 265 caddr_t from; 266 char *nbuf; 267 268 snp = dev->si_drv1; 269 KASSERT(snp->snp_len + snp->snp_base <= snp->snp_blen, 270 ("snoop buffer error")); 271 272 if (snp->snp_tty == NULL) 273 return (EIO); 274 275 snp->snp_flags &= ~SNOOP_RWAIT; 276 277 do { 278 if (snp->snp_len == 0) { 279 if (flag & O_NONBLOCK) 280 return (EWOULDBLOCK); 281 snp->snp_flags |= SNOOP_RWAIT; 282 error = tsleep(snp, (PZERO + 1) | PCATCH, 283 "snprd", 0); 284 if (error != 0) 285 return (error); 286 } 287 } while (snp->snp_len == 0); 288 289 n = snp->snp_len; 290 291 error = 0; 292 while (snp->snp_len > 0 && uio->uio_resid > 0 && error == 0) { 293 len = min((unsigned)uio->uio_resid, snp->snp_len); 294 from = (caddr_t)(snp->snp_buf + snp->snp_base); 295 if (len == 0) 296 break; 297 298 error = uiomove(from, len, uio); 299 snp->snp_base += len; 300 snp->snp_len -= len; 301 } 302 if ((snp->snp_flags & SNOOP_OFLOW) && (n < snp->snp_len)) { 303 snp->snp_flags &= ~SNOOP_OFLOW; 304 } 305 s = spltty(); 306 nblen = snp->snp_blen; 307 if (((nblen / 2) >= SNOOP_MINLEN) && (nblen / 2) >= snp->snp_len) { 308 while (nblen / 2 >= snp->snp_len && nblen / 2 >= SNOOP_MINLEN) 309 nblen = nblen / 2; 310 if ((nbuf = malloc(nblen, M_SNP, M_NOWAIT)) != NULL) { 311 bcopy(snp->snp_buf + snp->snp_base, nbuf, snp->snp_len); 312 free(snp->snp_buf, M_SNP); 313 snp->snp_buf = nbuf; 314 snp->snp_blen = nblen; 315 snp->snp_base = 0; 316 } 317 } 318 splx(s); 319 320 return (error); 321 } 322 323 static int 324 snp_in(snp, buf, n) 325 struct snoop *snp; 326 char *buf; 327 int n; 328 { 329 int s_free, s_tail; 330 int s, len, nblen; 331 caddr_t from, to; 332 char *nbuf; 333 334 KASSERT(n >= 0, ("negative snoop char count")); 335 336 if (n == 0) 337 return (0); 338 339 if (snp->snp_flags & SNOOP_DOWN) { 340 printf("snp%d: more data to down interface\n", snp->snp_unit); 341 return (0); 342 } 343 344 if (snp->snp_flags & SNOOP_OFLOW) { 345 printf("snp%d: buffer overflow\n", snp->snp_unit); 346 /* 347 * On overflow we just repeat the standart close 348 * procedure...yes , this is waste of space but.. Then next 349 * read from device will fail if one would recall he is 350 * snooping and retry... 351 */ 352 353 return (snp_down(snp)); 354 } 355 s_tail = snp->snp_blen - (snp->snp_len + snp->snp_base); 356 s_free = snp->snp_blen - snp->snp_len; 357 358 359 if (n > s_free) { 360 s = spltty(); 361 nblen = snp->snp_blen; 362 while ((n > s_free) && ((nblen * 2) <= SNOOP_MAXLEN)) { 363 nblen = snp->snp_blen * 2; 364 s_free = nblen - (snp->snp_len + snp->snp_base); 365 } 366 if ((n <= s_free) && (nbuf = malloc(nblen, M_SNP, M_NOWAIT))) { 367 bcopy(snp->snp_buf + snp->snp_base, nbuf, snp->snp_len); 368 free(snp->snp_buf, M_SNP); 369 snp->snp_buf = nbuf; 370 snp->snp_blen = nblen; 371 snp->snp_base = 0; 372 } else { 373 snp->snp_flags |= SNOOP_OFLOW; 374 if (snp->snp_flags & SNOOP_RWAIT) { 375 snp->snp_flags &= ~SNOOP_RWAIT; 376 wakeup(snp); 377 } 378 splx(s); 379 return (0); 380 } 381 splx(s); 382 } 383 if (n > s_tail) { 384 from = (caddr_t)(snp->snp_buf + snp->snp_base); 385 to = (caddr_t)(snp->snp_buf); 386 len = snp->snp_len; 387 bcopy(from, to, len); 388 snp->snp_base = 0; 389 } 390 to = (caddr_t)(snp->snp_buf + snp->snp_base + snp->snp_len); 391 bcopy(buf, to, n); 392 snp->snp_len += n; 393 394 if (snp->snp_flags & SNOOP_RWAIT) { 395 snp->snp_flags &= ~SNOOP_RWAIT; 396 wakeup(snp); 397 } 398 selwakeuppri(&snp->snp_sel, PZERO + 1); 399 400 return (n); 401 } 402 403 static int 404 snpopen(dev, flag, mode, td) 405 struct cdev *dev; 406 int flag, mode; 407 struct thread *td; 408 { 409 struct snoop *snp; 410 411 if (dev->si_drv1 == NULL) { 412 dev->si_flags &= ~SI_CHEAPCLONE; 413 dev->si_drv1 = snp = malloc(sizeof(*snp), M_SNP, 414 M_WAITOK | M_ZERO); 415 snp->snp_unit = dev2unit(dev); 416 } else 417 return (EBUSY); 418 419 /* 420 * We intentionally do not OR flags with SNOOP_OPEN, but set them so 421 * all previous settings (especially SNOOP_OFLOW) will be cleared. 422 */ 423 snp->snp_flags = SNOOP_OPEN; 424 425 snp->snp_buf = malloc(SNOOP_MINLEN, M_SNP, M_WAITOK); 426 snp->snp_blen = SNOOP_MINLEN; 427 snp->snp_base = 0; 428 snp->snp_len = 0; 429 430 /* 431 * snp_tty == NULL is for inactive snoop devices. 432 */ 433 snp->snp_tty = NULL; 434 snp->snp_target = NULL; 435 436 LIST_INSERT_HEAD(&snp_sclist, snp, snp_list); 437 return (0); 438 } 439 440 441 static int 442 snp_detach(snp) 443 struct snoop *snp; 444 { 445 struct tty *tp; 446 447 snp->snp_base = 0; 448 snp->snp_len = 0; 449 450 /* 451 * If line disc. changed we do not touch this pointer, SLIP/PPP will 452 * change it anyway. 453 */ 454 tp = snp->snp_tty; 455 if (tp == NULL) 456 goto detach_notty; 457 458 if ((tp->t_state & TS_SNOOP) && tp->t_line == snooplinedisc) { 459 tp->t_state &= ~TS_SNOOP; 460 tp->t_line = snp->snp_olddisc; 461 } else 462 printf("snp%d: bad attached tty data\n", snp->snp_unit); 463 464 snp->snp_tty = NULL; 465 snp->snp_target = NULL; 466 467 detach_notty: 468 selwakeuppri(&snp->snp_sel, PZERO + 1); 469 if ((snp->snp_flags & SNOOP_OPEN) == 0) 470 free(snp, M_SNP); 471 472 return (0); 473 } 474 475 static int 476 snpclose(dev, flags, fmt, td) 477 struct cdev *dev; 478 int flags; 479 int fmt; 480 struct thread *td; 481 { 482 struct snoop *snp; 483 484 snp = dev->si_drv1; 485 snp->snp_blen = 0; 486 LIST_REMOVE(snp, snp_list); 487 free(snp->snp_buf, M_SNP); 488 snp->snp_flags &= ~SNOOP_OPEN; 489 dev->si_drv1 = NULL; 490 destroy_dev(dev); 491 492 return (snp_detach(snp)); 493 } 494 495 static int 496 snp_down(snp) 497 struct snoop *snp; 498 { 499 500 if (snp->snp_blen != SNOOP_MINLEN) { 501 free(snp->snp_buf, M_SNP); 502 snp->snp_buf = malloc(SNOOP_MINLEN, M_SNP, M_WAITOK); 503 snp->snp_blen = SNOOP_MINLEN; 504 } 505 snp->snp_flags |= SNOOP_DOWN; 506 507 return (snp_detach(snp)); 508 } 509 510 static int 511 snpioctl(dev, cmd, data, flags, td) 512 struct cdev *dev; 513 u_long cmd; 514 caddr_t data; 515 int flags; 516 struct thread *td; 517 { 518 struct snoop *snp; 519 struct tty *tp, *tpo; 520 struct cdev *tdev; 521 int s; 522 523 snp = dev->si_drv1; 524 switch (cmd) { 525 case SNPSTTY: 526 tdev = findcdev(*((dev_t *)data)); 527 if (tdev == NULL) 528 return (snp_down(snp)); 529 530 tp = snpdevtotty(tdev); 531 if (!tp) 532 return (EINVAL); 533 if (tp->t_state & TS_SNOOP) 534 return (EBUSY); 535 536 s = spltty(); 537 538 if (snp->snp_target == NULL) { 539 tpo = snp->snp_tty; 540 if (tpo) 541 tpo->t_state &= ~TS_SNOOP; 542 } 543 544 tp->t_state |= TS_SNOOP; 545 snp->snp_olddisc = tp->t_line; 546 tp->t_line = snooplinedisc; 547 snp->snp_tty = tp; 548 snp->snp_target = tdev; 549 550 /* 551 * Clean overflow and down flags - 552 * we'll have a chance to get them in the future :))) 553 */ 554 snp->snp_flags &= ~SNOOP_OFLOW; 555 snp->snp_flags &= ~SNOOP_DOWN; 556 splx(s); 557 break; 558 559 case SNPGTTY: 560 /* 561 * We keep snp_target field specially to make 562 * SNPGTTY happy, else we can't know what is device 563 * major/minor for tty. 564 */ 565 *((dev_t *)data) = dev2udev(snp->snp_target); 566 break; 567 568 case FIONBIO: 569 break; 570 571 case FIOASYNC: 572 if (*(int *)data) 573 snp->snp_flags |= SNOOP_ASYNC; 574 else 575 snp->snp_flags &= ~SNOOP_ASYNC; 576 break; 577 578 case FIONREAD: 579 s = spltty(); 580 if (snp->snp_tty != NULL) 581 *(int *)data = snp->snp_len; 582 else 583 if (snp->snp_flags & SNOOP_DOWN) { 584 if (snp->snp_flags & SNOOP_OFLOW) 585 *(int *)data = SNP_OFLOW; 586 else 587 *(int *)data = SNP_TTYCLOSE; 588 } else { 589 *(int *)data = SNP_DETACH; 590 } 591 splx(s); 592 break; 593 594 default: 595 return (ENOTTY); 596 } 597 return (0); 598 } 599 600 static int 601 snppoll(dev, events, td) 602 struct cdev *dev; 603 int events; 604 struct thread *td; 605 { 606 struct snoop *snp; 607 int revents; 608 609 snp = dev->si_drv1; 610 revents = 0; 611 /* 612 * If snoop is down, we don't want to poll() forever so we return 1. 613 * Caller should see if we down via FIONREAD ioctl(). The last should 614 * return -1 to indicate down state. 615 */ 616 if (events & (POLLIN | POLLRDNORM)) { 617 if (snp->snp_flags & SNOOP_DOWN || snp->snp_len > 0) 618 revents |= events & (POLLIN | POLLRDNORM); 619 else 620 selrecord(td, &snp->snp_sel); 621 } 622 return (revents); 623 } 624 625 static void 626 snp_clone(arg, name, namelen, dev) 627 void *arg; 628 char *name; 629 int namelen; 630 struct cdev **dev; 631 { 632 int u, i; 633 634 if (*dev != NULL) 635 return; 636 if (dev_stdclone(name, NULL, "snp", &u) != 1) 637 return; 638 i = clone_create(&snpclones, &snp_cdevsw, &u, dev, 0); 639 if (i) 640 *dev = make_dev(&snp_cdevsw, unit2minor(u), 641 UID_ROOT, GID_WHEEL, 0600, "snp%d", u); 642 if (*dev != NULL) 643 (*dev)->si_flags |= SI_CHEAPCLONE; 644 } 645 646 static int 647 snp_modevent(mod, type, data) 648 module_t mod; 649 int type; 650 void *data; 651 { 652 static eventhandler_tag eh_tag; 653 654 switch (type) { 655 case MOD_LOAD: 656 /* XXX error checking. */ 657 clone_setup(&snpclones); 658 eh_tag = EVENTHANDLER_REGISTER(dev_clone, snp_clone, 0, 1000); 659 snooplinedisc = ldisc_register(LDISC_LOAD, &snpdisc); 660 break; 661 case MOD_UNLOAD: 662 if (!LIST_EMPTY(&snp_sclist)) 663 return (EBUSY); 664 EVENTHANDLER_DEREGISTER(dev_clone, eh_tag); 665 clone_cleanup(&snpclones); 666 ldisc_deregister(snooplinedisc); 667 break; 668 default: 669 return (EOPNOTSUPP); 670 break; 671 } 672 return (0); 673 } 674 675 static moduledata_t snp_mod = { 676 "snp", 677 snp_modevent, 678 NULL 679 }; 680 DECLARE_MODULE(snp, snp_mod, SI_SUB_DRIVERS, SI_ORDER_MIDDLE); 681