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 ttyopen, snplclose, ttread, snplwrite, 56 l_nullioctl, ttyinput, ttstart, ttymodem 57 }; 58 59 /* 60 * This is the main snoop per-device structure. 61 */ 62 struct snoop { 63 LIST_ENTRY(snoop) snp_list; /* List glue. */ 64 int snp_unit; /* Device number. */ 65 struct cdev *snp_target; /* Target tty device. */ 66 struct tty *snp_tty; /* Target tty pointer. */ 67 u_long snp_len; /* Possible length. */ 68 u_long snp_base; /* Data base. */ 69 u_long snp_blen; /* Used length. */ 70 caddr_t snp_buf; /* Allocation pointer. */ 71 int snp_flags; /* Flags. */ 72 struct selinfo snp_sel; /* Select info. */ 73 int snp_olddisc; /* Old line discipline. */ 74 }; 75 76 /* 77 * Possible flags. 78 */ 79 #define SNOOP_ASYNC 0x0002 80 #define SNOOP_OPEN 0x0004 81 #define SNOOP_RWAIT 0x0008 82 #define SNOOP_OFLOW 0x0010 83 #define SNOOP_DOWN 0x0020 84 85 /* 86 * Other constants. 87 */ 88 #define SNOOP_MINLEN (4*1024) /* This should be power of 2. 89 * 4K tested to be the minimum 90 * for which on normal tty 91 * usage there is no need to 92 * allocate more. 93 */ 94 #define SNOOP_MAXLEN (64*1024) /* This one also,64K enough 95 * If we grow more,something 96 * really bad in this world.. 97 */ 98 99 static MALLOC_DEFINE(M_SNP, "snp", "Snoop device data"); 100 /* 101 * The number of the "snoop" line discipline. This gets determined at 102 * module load time. 103 */ 104 static int snooplinedisc; 105 106 static LIST_HEAD(, snoop) snp_sclist = LIST_HEAD_INITIALIZER(&snp_sclist); 107 static struct clonedevs *snpclones; 108 109 static struct tty *snpdevtotty(struct cdev *dev); 110 static void snp_clone(void *arg, char *name, 111 int namelen, struct cdev **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 struct cdev *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 struct cdev *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 struct cdev *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 selwakeuppri(&snp->snp_sel, PZERO + 1); 374 375 return (n); 376 } 377 378 static int 379 snpopen(dev, flag, mode, td) 380 struct cdev *dev; 381 int flag, mode; 382 struct thread *td; 383 { 384 struct snoop *snp; 385 386 if (dev->si_drv1 == NULL) { 387 dev->si_flags &= ~SI_CHEAPCLONE; 388 dev->si_drv1 = snp = malloc(sizeof(*snp), M_SNP, 389 M_WAITOK | M_ZERO); 390 snp->snp_unit = dev2unit(dev); 391 } else 392 return (EBUSY); 393 394 /* 395 * We intentionally do not OR flags with SNOOP_OPEN, but set them so 396 * all previous settings (especially SNOOP_OFLOW) will be cleared. 397 */ 398 snp->snp_flags = SNOOP_OPEN; 399 400 snp->snp_buf = malloc(SNOOP_MINLEN, M_SNP, M_WAITOK); 401 snp->snp_blen = SNOOP_MINLEN; 402 snp->snp_base = 0; 403 snp->snp_len = 0; 404 405 /* 406 * snp_tty == NULL is for inactive snoop devices. 407 */ 408 snp->snp_tty = NULL; 409 snp->snp_target = NULL; 410 411 LIST_INSERT_HEAD(&snp_sclist, snp, snp_list); 412 return (0); 413 } 414 415 416 static int 417 snp_detach(snp) 418 struct snoop *snp; 419 { 420 struct tty *tp; 421 422 snp->snp_base = 0; 423 snp->snp_len = 0; 424 425 /* 426 * If line disc. changed we do not touch this pointer, SLIP/PPP will 427 * change it anyway. 428 */ 429 tp = snp->snp_tty; 430 if (tp == NULL) 431 goto detach_notty; 432 433 if (tp && (tp->t_sc == snp) && (tp->t_state & TS_SNOOP) && 434 tp->t_line == snooplinedisc) { 435 tp->t_sc = NULL; 436 tp->t_state &= ~TS_SNOOP; 437 tp->t_line = snp->snp_olddisc; 438 } else 439 printf("snp%d: bad attached tty data\n", snp->snp_unit); 440 441 snp->snp_tty = NULL; 442 snp->snp_target = NULL; 443 444 detach_notty: 445 selwakeuppri(&snp->snp_sel, PZERO + 1); 446 if ((snp->snp_flags & SNOOP_OPEN) == 0) 447 free(snp, M_SNP); 448 449 return (0); 450 } 451 452 static int 453 snpclose(dev, flags, fmt, td) 454 struct cdev *dev; 455 int flags; 456 int fmt; 457 struct thread *td; 458 { 459 struct snoop *snp; 460 461 snp = dev->si_drv1; 462 snp->snp_blen = 0; 463 LIST_REMOVE(snp, snp_list); 464 free(snp->snp_buf, M_SNP); 465 snp->snp_flags &= ~SNOOP_OPEN; 466 dev->si_drv1 = NULL; 467 destroy_dev(dev); 468 469 return (snp_detach(snp)); 470 } 471 472 static int 473 snp_down(snp) 474 struct snoop *snp; 475 { 476 477 if (snp->snp_blen != SNOOP_MINLEN) { 478 free(snp->snp_buf, M_SNP); 479 snp->snp_buf = malloc(SNOOP_MINLEN, M_SNP, M_WAITOK); 480 snp->snp_blen = SNOOP_MINLEN; 481 } 482 snp->snp_flags |= SNOOP_DOWN; 483 484 return (snp_detach(snp)); 485 } 486 487 static int 488 snpioctl(dev, cmd, data, flags, td) 489 struct cdev *dev; 490 u_long cmd; 491 caddr_t data; 492 int flags; 493 struct thread *td; 494 { 495 struct snoop *snp; 496 struct tty *tp, *tpo; 497 struct cdev *tdev; 498 int s; 499 500 snp = dev->si_drv1; 501 switch (cmd) { 502 case SNPSTTY: 503 tdev = findcdev(*((dev_t *)data)); 504 if (tdev == NULL) 505 return (snp_down(snp)); 506 507 tp = snpdevtotty(tdev); 508 if (!tp) 509 return (EINVAL); 510 if (tp->t_state & TS_SNOOP) 511 return (EBUSY); 512 513 s = spltty(); 514 515 if (snp->snp_target == NULL) { 516 tpo = snp->snp_tty; 517 if (tpo) 518 tpo->t_state &= ~TS_SNOOP; 519 } 520 521 tp->t_sc = (caddr_t)snp; 522 tp->t_state |= TS_SNOOP; 523 snp->snp_olddisc = tp->t_line; 524 tp->t_line = snooplinedisc; 525 snp->snp_tty = tp; 526 snp->snp_target = tdev; 527 528 /* 529 * Clean overflow and down flags - 530 * we'll have a chance to get them in the future :))) 531 */ 532 snp->snp_flags &= ~SNOOP_OFLOW; 533 snp->snp_flags &= ~SNOOP_DOWN; 534 splx(s); 535 break; 536 537 case SNPGTTY: 538 /* 539 * We keep snp_target field specially to make 540 * SNPGTTY happy, else we can't know what is device 541 * major/minor for tty. 542 */ 543 *((dev_t *)data) = dev2udev(snp->snp_target); 544 break; 545 546 case FIONBIO: 547 break; 548 549 case FIOASYNC: 550 if (*(int *)data) 551 snp->snp_flags |= SNOOP_ASYNC; 552 else 553 snp->snp_flags &= ~SNOOP_ASYNC; 554 break; 555 556 case FIONREAD: 557 s = spltty(); 558 if (snp->snp_tty != NULL) 559 *(int *)data = snp->snp_len; 560 else 561 if (snp->snp_flags & SNOOP_DOWN) { 562 if (snp->snp_flags & SNOOP_OFLOW) 563 *(int *)data = SNP_OFLOW; 564 else 565 *(int *)data = SNP_TTYCLOSE; 566 } else { 567 *(int *)data = SNP_DETACH; 568 } 569 splx(s); 570 break; 571 572 default: 573 return (ENOTTY); 574 } 575 return (0); 576 } 577 578 static int 579 snppoll(dev, events, td) 580 struct cdev *dev; 581 int events; 582 struct thread *td; 583 { 584 struct snoop *snp; 585 int revents; 586 587 snp = dev->si_drv1; 588 revents = 0; 589 /* 590 * If snoop is down, we don't want to poll() forever so we return 1. 591 * Caller should see if we down via FIONREAD ioctl(). The last should 592 * return -1 to indicate down state. 593 */ 594 if (events & (POLLIN | POLLRDNORM)) { 595 if (snp->snp_flags & SNOOP_DOWN || snp->snp_len > 0) 596 revents |= events & (POLLIN | POLLRDNORM); 597 else 598 selrecord(td, &snp->snp_sel); 599 } 600 return (revents); 601 } 602 603 static void 604 snp_clone(arg, name, namelen, dev) 605 void *arg; 606 char *name; 607 int namelen; 608 struct cdev **dev; 609 { 610 int u, i; 611 612 if (*dev != NULL) 613 return; 614 if (dev_stdclone(name, NULL, "snp", &u) != 1) 615 return; 616 i = clone_create(&snpclones, &snp_cdevsw, &u, dev, 0); 617 if (i) 618 *dev = make_dev(&snp_cdevsw, unit2minor(u), 619 UID_ROOT, GID_WHEEL, 0600, "snp%d", u); 620 if (*dev != NULL) 621 (*dev)->si_flags |= SI_CHEAPCLONE; 622 } 623 624 static int 625 snp_modevent(mod, type, data) 626 module_t mod; 627 int type; 628 void *data; 629 { 630 static eventhandler_tag eh_tag; 631 632 switch (type) { 633 case MOD_LOAD: 634 /* XXX error checking. */ 635 clone_setup(&snpclones); 636 eh_tag = EVENTHANDLER_REGISTER(dev_clone, snp_clone, 0, 1000); 637 snooplinedisc = ldisc_register(LDISC_LOAD, &snpdisc); 638 break; 639 case MOD_UNLOAD: 640 if (!LIST_EMPTY(&snp_sclist)) 641 return (EBUSY); 642 EVENTHANDLER_DEREGISTER(dev_clone, eh_tag); 643 clone_cleanup(&snpclones); 644 ldisc_deregister(snooplinedisc); 645 break; 646 default: 647 break; 648 } 649 return (0); 650 } 651 652 static moduledata_t snp_mod = { 653 "snp", 654 snp_modevent, 655 NULL 656 }; 657 DECLARE_MODULE(snp, snp_mod, SI_SUB_DRIVERS, SI_ORDER_MIDDLE); 658