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