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: src/sys/dev/snp/snp.c,v 1.69.2.2 2002/05/06 07:30:02 dd Exp $ 16 * $DragonFly: src/sys/dev/misc/snp/snp.c,v 1.8 2003/08/27 10:35:18 rob Exp $ 17 */ 18 19 #include <sys/param.h> 20 #include <sys/systm.h> 21 #include <sys/filio.h> 22 #include <sys/malloc.h> 23 #include <sys/tty.h> 24 #include <sys/conf.h> 25 #include <sys/poll.h> 26 #include <sys/kernel.h> 27 #include <sys/queue.h> 28 #include <sys/snoop.h> 29 #include <sys/vnode.h> 30 #include <sys/device.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 /* name */ "snp", 44 /* maj */ CDEV_MAJOR, 45 /* flags */ 0, 46 /* port */ NULL, 47 /* autoq */ 0, 48 49 /* open */ snpopen, 50 /* close */ snpclose, 51 /* read */ snpread, 52 /* write */ snpwrite, 53 /* ioctl */ snpioctl, 54 /* poll */ snppoll, 55 /* mmap */ nommap, 56 /* strategy */ nostrategy, 57 /* dump */ nodump, 58 /* psize */ nopsize 59 }; 60 61 static struct linesw snpdisc = { 62 ttyopen, snplclose, ttread, snplwrite, 63 l_nullioctl, ttyinput, ttstart, 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 dev_t 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; 111 112 113 static LIST_HEAD(, snoop) snp_sclist = LIST_HEAD_INITIALIZER(&snp_sclist); 114 115 static struct tty *snpdevtotty (dev_t dev); 116 static int snp_detach (struct snoop *snp); 117 static int snp_down (struct snoop *snp); 118 static int snp_in (struct snoop *snp, char *buf, int n); 119 static int snp_modevent (module_t mod, int what, void *arg); 120 121 static int 122 snplclose(tp, flag) 123 struct tty *tp; 124 int flag; 125 { 126 struct snoop *snp; 127 int error; 128 129 snp = tp->t_sc; 130 error = snp_down(snp); 131 if (error != 0) 132 return (error); 133 error = ttylclose(tp, flag); 134 return (error); 135 } 136 137 static int 138 snplwrite(tp, uio, flag) 139 struct tty *tp; 140 struct uio *uio; 141 int flag; 142 { 143 struct iovec iov; 144 struct uio uio2; 145 struct snoop *snp; 146 int error, ilen; 147 char *ibuf; 148 149 error = 0; 150 ibuf = NULL; 151 snp = tp->t_sc; 152 while (uio->uio_resid > 0) { 153 ilen = imin(512, uio->uio_resid); 154 ibuf = malloc(ilen, M_SNP, M_WAITOK); 155 error = uiomove(ibuf, ilen, uio); 156 if (error != 0) 157 break; 158 snp_in(snp, ibuf, ilen); 159 /* Hackish, but probably the least of all evils. */ 160 iov.iov_base = ibuf; 161 iov.iov_len = ilen; 162 uio2.uio_iov = &iov; 163 uio2.uio_iovcnt = 1; 164 uio2.uio_offset = 0; 165 uio2.uio_resid = ilen; 166 uio2.uio_segflg = UIO_SYSSPACE; 167 uio2.uio_rw = UIO_WRITE; 168 uio2.uio_td = uio->uio_td; 169 error = ttwrite(tp, &uio2, flag); 170 if (error != 0) 171 break; 172 free(ibuf, M_SNP); 173 ibuf = NULL; 174 } 175 if (ibuf != NULL) 176 free(ibuf, M_SNP); 177 return (error); 178 } 179 180 static struct tty * 181 snpdevtotty(dev) 182 dev_t dev; 183 { 184 if ((dev_dflags(dev) & D_TTY) == 0) 185 return (NULL); 186 return (dev->si_tty); 187 } 188 189 #define SNP_INPUT_BUF 5 /* This is even too much, the maximal 190 * interactive mode write is 3 bytes 191 * length for function keys... 192 */ 193 194 static int 195 snpwrite(dev, uio, flag) 196 dev_t dev; 197 struct uio *uio; 198 int flag; 199 { 200 struct snoop *snp; 201 struct tty *tp; 202 int error, i, len; 203 unsigned char c[SNP_INPUT_BUF]; 204 205 snp = dev->si_drv1; 206 tp = snp->snp_tty; 207 if (tp == NULL) 208 return (EIO); 209 if ((tp->t_sc == snp) && (tp->t_state & TS_SNOOP) && 210 tp->t_line == snooplinedisc) 211 goto tty_input; 212 213 printf("Snoop: attempt to write to bad tty.\n"); 214 return (EIO); 215 216 tty_input: 217 if (!(tp->t_state & TS_ISOPEN)) 218 return (EIO); 219 220 while (uio->uio_resid > 0) { 221 len = imin(uio->uio_resid, SNP_INPUT_BUF); 222 if ((error = uiomove(c, len, uio)) != 0) 223 return (error); 224 for (i=0; i < len; i++) { 225 if (ttyinput(c[i], tp)) 226 return (EIO); 227 } 228 } 229 return (0); 230 } 231 232 233 static int 234 snpread(dev, uio, flag) 235 dev_t dev; 236 struct uio *uio; 237 int flag; 238 { 239 struct snoop *snp; 240 int error, len, n, nblen, s; 241 caddr_t from; 242 char *nbuf; 243 244 snp = dev->si_drv1; 245 KASSERT(snp->snp_len + snp->snp_base <= snp->snp_blen, 246 ("snoop buffer error")); 247 248 if (snp->snp_tty == NULL) 249 return (EIO); 250 251 snp->snp_flags &= ~SNOOP_RWAIT; 252 253 do { 254 if (snp->snp_len == 0) { 255 if (flag & IO_NDELAY) 256 return (EWOULDBLOCK); 257 snp->snp_flags |= SNOOP_RWAIT; 258 error = tsleep((caddr_t)snp, PCATCH, "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("Snoop: more data to down interface.\n"); 316 return (0); 317 } 318 319 if (snp->snp_flags & SNOOP_OFLOW) { 320 printf("Snoop: buffer overflow.\n"); 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((caddr_t)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((caddr_t)snp); 372 } 373 selwakeup(&snp->snp_sel); 374 snp->snp_sel.si_pid = 0; 375 376 return (n); 377 } 378 379 static int 380 snpopen(dev_t dev, int flag, int mode, d_thread_t *td) 381 { 382 struct snoop *snp; 383 384 if (dev->si_drv1 == NULL) { 385 make_dev(&snp_cdevsw, minor(dev), UID_ROOT, GID_WHEEL, 386 0600, "snp%d", minor(dev)); 387 dev->si_drv1 = snp = malloc(sizeof(*snp), M_SNP, 388 M_WAITOK | M_ZERO); 389 } else 390 return (EBUSY); 391 392 /* 393 * We intentionally do not OR flags with SNOOP_OPEN, but set them so 394 * all previous settings (especially SNOOP_OFLOW) will be cleared. 395 */ 396 snp->snp_flags = SNOOP_OPEN; 397 398 snp->snp_buf = malloc(SNOOP_MINLEN, M_SNP, M_WAITOK); 399 snp->snp_blen = SNOOP_MINLEN; 400 snp->snp_base = 0; 401 snp->snp_len = 0; 402 403 /* 404 * snp_tty == NULL is for inactive snoop devices. 405 */ 406 snp->snp_tty = NULL; 407 snp->snp_target = NODEV; 408 409 LIST_INSERT_HEAD(&snp_sclist, snp, snp_list); 410 return (0); 411 } 412 413 414 static int 415 snp_detach(snp) 416 struct snoop *snp; 417 { 418 struct tty *tp; 419 420 snp->snp_base = 0; 421 snp->snp_len = 0; 422 423 /* 424 * If line disc. changed we do not touch this pointer, SLIP/PPP will 425 * change it anyway. 426 */ 427 tp = snp->snp_tty; 428 if (tp == NULL) 429 goto detach_notty; 430 431 if (tp && (tp->t_sc == snp) && (tp->t_state & TS_SNOOP) && 432 tp->t_line == snooplinedisc) { 433 tp->t_sc = NULL; 434 tp->t_state &= ~TS_SNOOP; 435 tp->t_line = snp->snp_olddisc; 436 } else 437 printf("Snoop: bad attached tty data.\n"); 438 439 snp->snp_tty = NULL; 440 snp->snp_target = NODEV; 441 442 detach_notty: 443 selwakeup(&snp->snp_sel); 444 snp->snp_sel.si_pid = 0; 445 if ((snp->snp_flags & SNOOP_OPEN) == 0) 446 free(snp, M_SNP); 447 448 return (0); 449 } 450 451 static int 452 snpclose(dev_t dev, int flags, int fmt, d_thread_t *td) 453 { 454 struct snoop *snp; 455 456 snp = dev->si_drv1; 457 snp->snp_blen = 0; 458 LIST_REMOVE(snp, snp_list); 459 free(snp->snp_buf, M_SNP); 460 snp->snp_flags &= ~SNOOP_OPEN; 461 dev->si_drv1 = NULL; 462 463 return (snp_detach(snp)); 464 } 465 466 static int 467 snp_down(snp) 468 struct snoop *snp; 469 { 470 471 if (snp->snp_blen != SNOOP_MINLEN) { 472 free(snp->snp_buf, M_SNP); 473 snp->snp_buf = malloc(SNOOP_MINLEN, M_SNP, M_WAITOK); 474 snp->snp_blen = SNOOP_MINLEN; 475 } 476 snp->snp_flags |= SNOOP_DOWN; 477 478 return (snp_detach(snp)); 479 } 480 481 static int 482 snpioctl(dev_t dev, u_long cmd, caddr_t data, int flags, d_thread_t *td) 483 { 484 struct snoop *snp; 485 struct tty *tp, *tpo; 486 dev_t tdev; 487 int s; 488 489 snp = dev->si_drv1; 490 switch (cmd) { 491 case SNPSTTY: 492 tdev = udev2dev(*((udev_t *)data), 0); 493 if (tdev == NODEV) 494 return (snp_down(snp)); 495 496 tp = snpdevtotty(tdev); 497 if (!tp) 498 return (EINVAL); 499 if (tp->t_state & TS_SNOOP) 500 return (EBUSY); 501 502 s = spltty(); 503 504 if (snp->snp_target == NODEV) { 505 tpo = snp->snp_tty; 506 if (tpo) 507 tpo->t_state &= ~TS_SNOOP; 508 } 509 510 tp->t_sc = (caddr_t)snp; 511 tp->t_state |= TS_SNOOP; 512 snp->snp_olddisc = tp->t_line; 513 tp->t_line = snooplinedisc; 514 snp->snp_tty = tp; 515 snp->snp_target = tdev; 516 517 /* 518 * Clean overflow and down flags - 519 * we'll have a chance to get them in the future :))) 520 */ 521 snp->snp_flags &= ~SNOOP_OFLOW; 522 snp->snp_flags &= ~SNOOP_DOWN; 523 splx(s); 524 break; 525 526 case SNPGTTY: 527 /* 528 * We keep snp_target field specially to make 529 * SNPGTTY happy, else we can't know what is device 530 * major/minor for tty. 531 */ 532 *((dev_t *)data) = snp->snp_target; 533 break; 534 535 case FIONBIO: 536 break; 537 538 case FIOASYNC: 539 if (*(int *)data) 540 snp->snp_flags |= SNOOP_ASYNC; 541 else 542 snp->snp_flags &= ~SNOOP_ASYNC; 543 break; 544 545 case FIONREAD: 546 s = spltty(); 547 if (snp->snp_tty != NULL) 548 *(int *)data = snp->snp_len; 549 else 550 if (snp->snp_flags & SNOOP_DOWN) { 551 if (snp->snp_flags & SNOOP_OFLOW) 552 *(int *)data = SNP_OFLOW; 553 else 554 *(int *)data = SNP_TTYCLOSE; 555 } else { 556 *(int *)data = SNP_DETACH; 557 } 558 splx(s); 559 break; 560 561 default: 562 return (ENOTTY); 563 } 564 return (0); 565 } 566 567 static int 568 snppoll(dev_t dev, int events, d_thread_t *td) 569 { 570 struct snoop *snp; 571 int revents; 572 573 snp = dev->si_drv1; 574 revents = 0; 575 /* 576 * If snoop is down, we don't want to poll() forever so we return 1. 577 * Caller should see if we down via FIONREAD ioctl(). The last should 578 * return -1 to indicate down state. 579 */ 580 if (events & (POLLIN | POLLRDNORM)) { 581 if (snp->snp_flags & SNOOP_DOWN || snp->snp_len > 0) 582 revents |= events & (POLLIN | POLLRDNORM); 583 else 584 selrecord(td, &snp->snp_sel); 585 } 586 return (revents); 587 } 588 589 static int 590 snp_modevent(mod, type, data) 591 module_t mod; 592 int type; 593 void *data; 594 { 595 596 switch (type) { 597 case MOD_LOAD: 598 snooplinedisc = ldisc_register(LDISC_LOAD, &snpdisc); 599 cdevsw_add(&snp_cdevsw); 600 break; 601 case MOD_UNLOAD: 602 if (!LIST_EMPTY(&snp_sclist)) 603 return (EBUSY); 604 ldisc_deregister(snooplinedisc); 605 cdevsw_remove(&snp_cdevsw); 606 break; 607 default: 608 break; 609 } 610 return (0); 611 } 612 613 static moduledata_t snp_mod = { 614 "snp", 615 snp_modevent, 616 NULL 617 }; 618 DECLARE_MODULE(snp, snp_mod, SI_SUB_DRIVERS, SI_ORDER_MIDDLE + CDEV_MAJOR); 619