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 1.11 2005/06/16 16:27:05 joerg 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/thread2.h> 30 #include <sys/vnode.h> 31 #include <sys/device.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 #define CDEV_MAJOR 53 43 static struct cdevsw snp_cdevsw = { 44 /* name */ "snp", 45 /* maj */ CDEV_MAJOR, 46 /* flags */ 0, 47 /* port */ NULL, 48 /* clone */ NULL, 49 50 /* open */ snpopen, 51 /* close */ snpclose, 52 /* read */ snpread, 53 /* write */ snpwrite, 54 /* ioctl */ snpioctl, 55 /* poll */ snppoll, 56 /* mmap */ nommap, 57 /* strategy */ nostrategy, 58 /* dump */ nodump, 59 /* psize */ nopsize 60 }; 61 62 static struct linesw snpdisc = { 63 ttyopen, snplclose, ttread, snplwrite, 64 l_nullioctl, ttyinput, ttstart, ttymodem 65 }; 66 67 /* 68 * This is the main snoop per-device structure. 69 */ 70 struct snoop { 71 LIST_ENTRY(snoop) snp_list; /* List glue. */ 72 dev_t 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; 112 113 114 static LIST_HEAD(, snoop) snp_sclist = LIST_HEAD_INITIALIZER(&snp_sclist); 115 116 static struct tty *snpdevtotty (dev_t dev); 117 static int snp_detach (struct snoop *snp); 118 static int snp_down (struct snoop *snp); 119 static int snp_in (struct snoop *snp, char *buf, int n); 120 static int snp_modevent (module_t mod, int what, void *arg); 121 122 static int 123 snplclose(tp, flag) 124 struct tty *tp; 125 int flag; 126 { 127 struct snoop *snp; 128 int error; 129 130 snp = tp->t_sc; 131 error = snp_down(snp); 132 if (error != 0) 133 return (error); 134 error = ttylclose(tp, flag); 135 return (error); 136 } 137 138 static int 139 snplwrite(tp, uio, flag) 140 struct tty *tp; 141 struct uio *uio; 142 int flag; 143 { 144 struct iovec iov; 145 struct uio uio2; 146 struct snoop *snp; 147 int error, ilen; 148 char *ibuf; 149 150 error = 0; 151 ibuf = NULL; 152 snp = tp->t_sc; 153 while (uio->uio_resid > 0) { 154 ilen = imin(512, uio->uio_resid); 155 ibuf = malloc(ilen, M_SNP, M_WAITOK); 156 error = uiomove(ibuf, ilen, uio); 157 if (error != 0) 158 break; 159 snp_in(snp, ibuf, ilen); 160 /* Hackish, but probably the least of all evils. */ 161 iov.iov_base = ibuf; 162 iov.iov_len = ilen; 163 uio2.uio_iov = &iov; 164 uio2.uio_iovcnt = 1; 165 uio2.uio_offset = 0; 166 uio2.uio_resid = ilen; 167 uio2.uio_segflg = UIO_SYSSPACE; 168 uio2.uio_rw = UIO_WRITE; 169 uio2.uio_td = uio->uio_td; 170 error = ttwrite(tp, &uio2, flag); 171 if (error != 0) 172 break; 173 free(ibuf, M_SNP); 174 ibuf = NULL; 175 } 176 if (ibuf != NULL) 177 free(ibuf, M_SNP); 178 return (error); 179 } 180 181 static struct tty * 182 snpdevtotty(dev) 183 dev_t dev; 184 { 185 if ((dev_dflags(dev) & D_TTY) == 0) 186 return (NULL); 187 return (dev->si_tty); 188 } 189 190 #define SNP_INPUT_BUF 5 /* This is even too much, the maximal 191 * interactive mode write is 3 bytes 192 * length for function keys... 193 */ 194 195 static int 196 snpwrite(dev, uio, flag) 197 dev_t dev; 198 struct uio *uio; 199 int flag; 200 { 201 struct snoop *snp; 202 struct tty *tp; 203 int error, i, len; 204 unsigned char c[SNP_INPUT_BUF]; 205 206 snp = dev->si_drv1; 207 tp = snp->snp_tty; 208 if (tp == NULL) 209 return (EIO); 210 if ((tp->t_sc == snp) && (tp->t_state & TS_SNOOP) && 211 tp->t_line == snooplinedisc) 212 goto tty_input; 213 214 printf("Snoop: attempt to write to bad tty.\n"); 215 return (EIO); 216 217 tty_input: 218 if (!(tp->t_state & TS_ISOPEN)) 219 return (EIO); 220 221 while (uio->uio_resid > 0) { 222 len = imin(uio->uio_resid, SNP_INPUT_BUF); 223 if ((error = uiomove(c, len, uio)) != 0) 224 return (error); 225 for (i=0; i < len; i++) { 226 if (ttyinput(c[i], tp)) 227 return (EIO); 228 } 229 } 230 return (0); 231 } 232 233 234 static int 235 snpread(dev, uio, flag) 236 dev_t dev; 237 struct uio *uio; 238 int flag; 239 { 240 struct snoop *snp; 241 int error, len, n, nblen; 242 caddr_t from; 243 char *nbuf; 244 245 snp = dev->si_drv1; 246 KASSERT(snp->snp_len + snp->snp_base <= snp->snp_blen, 247 ("snoop buffer error")); 248 249 if (snp->snp_tty == NULL) 250 return (EIO); 251 252 snp->snp_flags &= ~SNOOP_RWAIT; 253 254 do { 255 if (snp->snp_len == 0) { 256 if (flag & IO_NDELAY) 257 return (EWOULDBLOCK); 258 snp->snp_flags |= SNOOP_RWAIT; 259 error = tsleep((caddr_t)snp, PCATCH, "snprd", 0); 260 if (error != 0) 261 return (error); 262 } 263 } while (snp->snp_len == 0); 264 265 n = snp->snp_len; 266 267 error = 0; 268 while (snp->snp_len > 0 && uio->uio_resid > 0 && error == 0) { 269 len = min((unsigned)uio->uio_resid, snp->snp_len); 270 from = (caddr_t)(snp->snp_buf + snp->snp_base); 271 if (len == 0) 272 break; 273 274 error = uiomove(from, len, uio); 275 snp->snp_base += len; 276 snp->snp_len -= len; 277 } 278 if ((snp->snp_flags & SNOOP_OFLOW) && (n < snp->snp_len)) { 279 snp->snp_flags &= ~SNOOP_OFLOW; 280 } 281 crit_enter(); 282 nblen = snp->snp_blen; 283 if (((nblen / 2) >= SNOOP_MINLEN) && (nblen / 2) >= snp->snp_len) { 284 while (nblen / 2 >= snp->snp_len && nblen / 2 >= SNOOP_MINLEN) 285 nblen = nblen / 2; 286 if ((nbuf = malloc(nblen, M_SNP, M_NOWAIT)) != NULL) { 287 bcopy(snp->snp_buf + snp->snp_base, nbuf, snp->snp_len); 288 free(snp->snp_buf, M_SNP); 289 snp->snp_buf = nbuf; 290 snp->snp_blen = nblen; 291 snp->snp_base = 0; 292 } 293 } 294 crit_exit(); 295 296 return (error); 297 } 298 299 static int 300 snp_in(snp, buf, n) 301 struct snoop *snp; 302 char *buf; 303 int n; 304 { 305 int s_free, s_tail; 306 int len, nblen; 307 caddr_t from, to; 308 char *nbuf; 309 310 KASSERT(n >= 0, ("negative snoop char count")); 311 312 if (n == 0) 313 return (0); 314 315 if (snp->snp_flags & SNOOP_DOWN) { 316 printf("Snoop: more data to down interface.\n"); 317 return (0); 318 } 319 320 if (snp->snp_flags & SNOOP_OFLOW) { 321 printf("Snoop: buffer overflow.\n"); 322 /* 323 * On overflow we just repeat the standart close 324 * procedure...yes , this is waste of space but.. Then next 325 * read from device will fail if one would recall he is 326 * snooping and retry... 327 */ 328 329 return (snp_down(snp)); 330 } 331 s_tail = snp->snp_blen - (snp->snp_len + snp->snp_base); 332 s_free = snp->snp_blen - snp->snp_len; 333 334 335 if (n > s_free) { 336 crit_enter(); 337 nblen = snp->snp_blen; 338 while ((n > s_free) && ((nblen * 2) <= SNOOP_MAXLEN)) { 339 nblen = snp->snp_blen * 2; 340 s_free = nblen - (snp->snp_len + snp->snp_base); 341 } 342 if ((n <= s_free) && (nbuf = malloc(nblen, M_SNP, M_NOWAIT))) { 343 bcopy(snp->snp_buf + snp->snp_base, nbuf, snp->snp_len); 344 free(snp->snp_buf, M_SNP); 345 snp->snp_buf = nbuf; 346 snp->snp_blen = nblen; 347 snp->snp_base = 0; 348 } else { 349 snp->snp_flags |= SNOOP_OFLOW; 350 if (snp->snp_flags & SNOOP_RWAIT) { 351 snp->snp_flags &= ~SNOOP_RWAIT; 352 wakeup((caddr_t)snp); 353 } 354 crit_exit(); 355 return (0); 356 } 357 crit_exit(); 358 } 359 if (n > s_tail) { 360 from = (caddr_t)(snp->snp_buf + snp->snp_base); 361 to = (caddr_t)(snp->snp_buf); 362 len = snp->snp_len; 363 bcopy(from, to, len); 364 snp->snp_base = 0; 365 } 366 to = (caddr_t)(snp->snp_buf + snp->snp_base + snp->snp_len); 367 bcopy(buf, to, n); 368 snp->snp_len += n; 369 370 if (snp->snp_flags & SNOOP_RWAIT) { 371 snp->snp_flags &= ~SNOOP_RWAIT; 372 wakeup((caddr_t)snp); 373 } 374 selwakeup(&snp->snp_sel); 375 snp->snp_sel.si_pid = 0; 376 377 return (n); 378 } 379 380 static int 381 snpopen(dev_t dev, int flag, int mode, d_thread_t *td) 382 { 383 struct snoop *snp; 384 385 if (dev->si_drv1 == NULL) { 386 make_dev(&snp_cdevsw, minor(dev), UID_ROOT, GID_WHEEL, 387 0600, "snp%d", minor(dev)); 388 dev->si_drv1 = snp = malloc(sizeof(*snp), M_SNP, 389 M_WAITOK | M_ZERO); 390 } else { 391 return (EBUSY); 392 } 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 = NODEV; 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("Snoop: bad attached tty data.\n"); 440 441 snp->snp_tty = NULL; 442 snp->snp_target = NODEV; 443 444 detach_notty: 445 selwakeup(&snp->snp_sel); 446 snp->snp_sel.si_pid = 0; 447 if ((snp->snp_flags & SNOOP_OPEN) == 0) 448 free(snp, M_SNP); 449 450 return (0); 451 } 452 453 static int 454 snpclose(dev_t dev, int flags, int fmt, d_thread_t *td) 455 { 456 struct snoop *snp; 457 458 snp = dev->si_drv1; 459 snp->snp_blen = 0; 460 LIST_REMOVE(snp, snp_list); 461 free(snp->snp_buf, M_SNP); 462 snp->snp_flags &= ~SNOOP_OPEN; 463 dev->si_drv1 = NULL; 464 465 return (snp_detach(snp)); 466 } 467 468 static int 469 snp_down(snp) 470 struct snoop *snp; 471 { 472 473 if (snp->snp_blen != SNOOP_MINLEN) { 474 free(snp->snp_buf, M_SNP); 475 snp->snp_buf = malloc(SNOOP_MINLEN, M_SNP, M_WAITOK); 476 snp->snp_blen = SNOOP_MINLEN; 477 } 478 snp->snp_flags |= SNOOP_DOWN; 479 480 return (snp_detach(snp)); 481 } 482 483 static int 484 snpioctl(dev_t dev, u_long cmd, caddr_t data, int flags, d_thread_t *td) 485 { 486 struct snoop *snp; 487 struct tty *tp, *tpo; 488 dev_t tdev; 489 490 snp = dev->si_drv1; 491 switch (cmd) { 492 case SNPSTTY: 493 tdev = udev2dev(*((udev_t *)data), 0); 494 if (tdev == NODEV) 495 return (snp_down(snp)); 496 497 tp = snpdevtotty(tdev); 498 if (!tp) 499 return (EINVAL); 500 if (tp->t_state & TS_SNOOP) 501 return (EBUSY); 502 503 crit_enter(); 504 505 if (snp->snp_target == NODEV) { 506 tpo = snp->snp_tty; 507 if (tpo) 508 tpo->t_state &= ~TS_SNOOP; 509 } 510 511 tp->t_sc = (caddr_t)snp; 512 tp->t_state |= TS_SNOOP; 513 snp->snp_olddisc = tp->t_line; 514 tp->t_line = snooplinedisc; 515 snp->snp_tty = tp; 516 snp->snp_target = tdev; 517 518 /* 519 * Clean overflow and down flags - 520 * we'll have a chance to get them in the future :))) 521 */ 522 snp->snp_flags &= ~SNOOP_OFLOW; 523 snp->snp_flags &= ~SNOOP_DOWN; 524 crit_exit(); 525 break; 526 527 case SNPGTTY: 528 /* 529 * We keep snp_target field specially to make 530 * SNPGTTY happy, else we can't know what is device 531 * major/minor for tty. 532 */ 533 *((dev_t *)data) = snp->snp_target; 534 break; 535 536 case FIONBIO: 537 break; 538 539 case FIOASYNC: 540 if (*(int *)data) 541 snp->snp_flags |= SNOOP_ASYNC; 542 else 543 snp->snp_flags &= ~SNOOP_ASYNC; 544 break; 545 546 case FIONREAD: 547 crit_enter(); 548 if (snp->snp_tty != NULL) 549 *(int *)data = snp->snp_len; 550 else 551 if (snp->snp_flags & SNOOP_DOWN) { 552 if (snp->snp_flags & SNOOP_OFLOW) 553 *(int *)data = SNP_OFLOW; 554 else 555 *(int *)data = SNP_TTYCLOSE; 556 } else { 557 *(int *)data = SNP_DETACH; 558 } 559 crit_exit(); 560 break; 561 562 default: 563 return (ENOTTY); 564 } 565 return (0); 566 } 567 568 static int 569 snppoll(dev_t dev, int events, d_thread_t *td) 570 { 571 struct snoop *snp; 572 int revents; 573 574 snp = dev->si_drv1; 575 revents = 0; 576 /* 577 * If snoop is down, we don't want to poll() forever so we return 1. 578 * Caller should see if we down via FIONREAD ioctl(). The last should 579 * return -1 to indicate down state. 580 */ 581 if (events & (POLLIN | POLLRDNORM)) { 582 if (snp->snp_flags & SNOOP_DOWN || snp->snp_len > 0) 583 revents |= events & (POLLIN | POLLRDNORM); 584 else 585 selrecord(td, &snp->snp_sel); 586 } 587 return (revents); 588 } 589 590 static int 591 snp_modevent(mod, type, data) 592 module_t mod; 593 int type; 594 void *data; 595 { 596 597 switch (type) { 598 case MOD_LOAD: 599 snooplinedisc = ldisc_register(LDISC_LOAD, &snpdisc); 600 cdevsw_add(&snp_cdevsw, 0, 0); 601 break; 602 case MOD_UNLOAD: 603 if (!LIST_EMPTY(&snp_sclist)) 604 return (EBUSY); 605 ldisc_deregister(snooplinedisc); 606 cdevsw_remove(&snp_cdevsw, 0, 0); 607 break; 608 default: 609 break; 610 } 611 return (0); 612 } 613 614 static moduledata_t snp_mod = { 615 "snp", 616 snp_modevent, 617 NULL 618 }; 619 DECLARE_MODULE(snp, snp_mod, SI_SUB_DRIVERS, SI_ORDER_MIDDLE + CDEV_MAJOR); 620