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 1.12 2005/12/11 01:54:08 swildner 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(struct tty *tp, int flag) 124 { 125 struct snoop *snp; 126 int error; 127 128 snp = tp->t_sc; 129 error = snp_down(snp); 130 if (error != 0) 131 return (error); 132 error = ttylclose(tp, flag); 133 return (error); 134 } 135 136 static int 137 snplwrite(struct tty *tp, struct uio *uio, 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_t dev) 178 { 179 if ((dev_dflags(dev) & D_TTY) == 0) 180 return (NULL); 181 return (dev->si_tty); 182 } 183 184 #define SNP_INPUT_BUF 5 /* This is even too much, the maximal 185 * interactive mode write is 3 bytes 186 * length for function keys... 187 */ 188 189 static int 190 snpwrite(dev_t dev, struct uio *uio, int flag) 191 { 192 struct snoop *snp; 193 struct tty *tp; 194 int error, i, len; 195 unsigned char c[SNP_INPUT_BUF]; 196 197 snp = dev->si_drv1; 198 tp = snp->snp_tty; 199 if (tp == NULL) 200 return (EIO); 201 if ((tp->t_sc == snp) && (tp->t_state & TS_SNOOP) && 202 tp->t_line == snooplinedisc) 203 goto tty_input; 204 205 printf("Snoop: attempt to write to bad tty.\n"); 206 return (EIO); 207 208 tty_input: 209 if (!(tp->t_state & TS_ISOPEN)) 210 return (EIO); 211 212 while (uio->uio_resid > 0) { 213 len = imin(uio->uio_resid, SNP_INPUT_BUF); 214 if ((error = uiomove(c, len, uio)) != 0) 215 return (error); 216 for (i=0; i < len; i++) { 217 if (ttyinput(c[i], tp)) 218 return (EIO); 219 } 220 } 221 return (0); 222 } 223 224 225 static int 226 snpread(dev_t dev, struct uio *uio, int flag) 227 { 228 struct snoop *snp; 229 int error, len, n, nblen; 230 caddr_t from; 231 char *nbuf; 232 233 snp = dev->si_drv1; 234 KASSERT(snp->snp_len + snp->snp_base <= snp->snp_blen, 235 ("snoop buffer error")); 236 237 if (snp->snp_tty == NULL) 238 return (EIO); 239 240 snp->snp_flags &= ~SNOOP_RWAIT; 241 242 do { 243 if (snp->snp_len == 0) { 244 if (flag & IO_NDELAY) 245 return (EWOULDBLOCK); 246 snp->snp_flags |= SNOOP_RWAIT; 247 error = tsleep((caddr_t)snp, PCATCH, "snprd", 0); 248 if (error != 0) 249 return (error); 250 } 251 } while (snp->snp_len == 0); 252 253 n = snp->snp_len; 254 255 error = 0; 256 while (snp->snp_len > 0 && uio->uio_resid > 0 && error == 0) { 257 len = min((unsigned)uio->uio_resid, snp->snp_len); 258 from = (caddr_t)(snp->snp_buf + snp->snp_base); 259 if (len == 0) 260 break; 261 262 error = uiomove(from, len, uio); 263 snp->snp_base += len; 264 snp->snp_len -= len; 265 } 266 if ((snp->snp_flags & SNOOP_OFLOW) && (n < snp->snp_len)) { 267 snp->snp_flags &= ~SNOOP_OFLOW; 268 } 269 crit_enter(); 270 nblen = snp->snp_blen; 271 if (((nblen / 2) >= SNOOP_MINLEN) && (nblen / 2) >= snp->snp_len) { 272 while (nblen / 2 >= snp->snp_len && nblen / 2 >= SNOOP_MINLEN) 273 nblen = nblen / 2; 274 if ((nbuf = malloc(nblen, M_SNP, M_NOWAIT)) != NULL) { 275 bcopy(snp->snp_buf + snp->snp_base, nbuf, snp->snp_len); 276 free(snp->snp_buf, M_SNP); 277 snp->snp_buf = nbuf; 278 snp->snp_blen = nblen; 279 snp->snp_base = 0; 280 } 281 } 282 crit_exit(); 283 284 return (error); 285 } 286 287 static int 288 snp_in(struct snoop *snp, char *buf, int n) 289 { 290 int s_free, s_tail; 291 int len, nblen; 292 caddr_t from, to; 293 char *nbuf; 294 295 KASSERT(n >= 0, ("negative snoop char count")); 296 297 if (n == 0) 298 return (0); 299 300 if (snp->snp_flags & SNOOP_DOWN) { 301 printf("Snoop: more data to down interface.\n"); 302 return (0); 303 } 304 305 if (snp->snp_flags & SNOOP_OFLOW) { 306 printf("Snoop: buffer overflow.\n"); 307 /* 308 * On overflow we just repeat the standart close 309 * procedure...yes , this is waste of space but.. Then next 310 * read from device will fail if one would recall he is 311 * snooping and retry... 312 */ 313 314 return (snp_down(snp)); 315 } 316 s_tail = snp->snp_blen - (snp->snp_len + snp->snp_base); 317 s_free = snp->snp_blen - snp->snp_len; 318 319 320 if (n > s_free) { 321 crit_enter(); 322 nblen = snp->snp_blen; 323 while ((n > s_free) && ((nblen * 2) <= SNOOP_MAXLEN)) { 324 nblen = snp->snp_blen * 2; 325 s_free = nblen - (snp->snp_len + snp->snp_base); 326 } 327 if ((n <= s_free) && (nbuf = malloc(nblen, M_SNP, M_NOWAIT))) { 328 bcopy(snp->snp_buf + snp->snp_base, nbuf, snp->snp_len); 329 free(snp->snp_buf, M_SNP); 330 snp->snp_buf = nbuf; 331 snp->snp_blen = nblen; 332 snp->snp_base = 0; 333 } else { 334 snp->snp_flags |= SNOOP_OFLOW; 335 if (snp->snp_flags & SNOOP_RWAIT) { 336 snp->snp_flags &= ~SNOOP_RWAIT; 337 wakeup((caddr_t)snp); 338 } 339 crit_exit(); 340 return (0); 341 } 342 crit_exit(); 343 } 344 if (n > s_tail) { 345 from = (caddr_t)(snp->snp_buf + snp->snp_base); 346 to = (caddr_t)(snp->snp_buf); 347 len = snp->snp_len; 348 bcopy(from, to, len); 349 snp->snp_base = 0; 350 } 351 to = (caddr_t)(snp->snp_buf + snp->snp_base + snp->snp_len); 352 bcopy(buf, to, n); 353 snp->snp_len += n; 354 355 if (snp->snp_flags & SNOOP_RWAIT) { 356 snp->snp_flags &= ~SNOOP_RWAIT; 357 wakeup((caddr_t)snp); 358 } 359 selwakeup(&snp->snp_sel); 360 snp->snp_sel.si_pid = 0; 361 362 return (n); 363 } 364 365 static int 366 snpopen(dev_t dev, int flag, int mode, d_thread_t *td) 367 { 368 struct snoop *snp; 369 370 if (dev->si_drv1 == NULL) { 371 make_dev(&snp_cdevsw, minor(dev), UID_ROOT, GID_WHEEL, 372 0600, "snp%d", minor(dev)); 373 dev->si_drv1 = snp = malloc(sizeof(*snp), M_SNP, 374 M_WAITOK | M_ZERO); 375 } else { 376 return (EBUSY); 377 } 378 379 /* 380 * We intentionally do not OR flags with SNOOP_OPEN, but set them so 381 * all previous settings (especially SNOOP_OFLOW) will be cleared. 382 */ 383 snp->snp_flags = SNOOP_OPEN; 384 385 snp->snp_buf = malloc(SNOOP_MINLEN, M_SNP, M_WAITOK); 386 snp->snp_blen = SNOOP_MINLEN; 387 snp->snp_base = 0; 388 snp->snp_len = 0; 389 390 /* 391 * snp_tty == NULL is for inactive snoop devices. 392 */ 393 snp->snp_tty = NULL; 394 snp->snp_target = NODEV; 395 396 LIST_INSERT_HEAD(&snp_sclist, snp, snp_list); 397 return (0); 398 } 399 400 401 static int 402 snp_detach(struct snoop *snp) 403 { 404 struct tty *tp; 405 406 snp->snp_base = 0; 407 snp->snp_len = 0; 408 409 /* 410 * If line disc. changed we do not touch this pointer, SLIP/PPP will 411 * change it anyway. 412 */ 413 tp = snp->snp_tty; 414 if (tp == NULL) 415 goto detach_notty; 416 417 if (tp && (tp->t_sc == snp) && (tp->t_state & TS_SNOOP) && 418 tp->t_line == snooplinedisc) { 419 tp->t_sc = NULL; 420 tp->t_state &= ~TS_SNOOP; 421 tp->t_line = snp->snp_olddisc; 422 } else 423 printf("Snoop: bad attached tty data.\n"); 424 425 snp->snp_tty = NULL; 426 snp->snp_target = NODEV; 427 428 detach_notty: 429 selwakeup(&snp->snp_sel); 430 snp->snp_sel.si_pid = 0; 431 if ((snp->snp_flags & SNOOP_OPEN) == 0) 432 free(snp, M_SNP); 433 434 return (0); 435 } 436 437 static int 438 snpclose(dev_t dev, int flags, int fmt, d_thread_t *td) 439 { 440 struct snoop *snp; 441 442 snp = dev->si_drv1; 443 snp->snp_blen = 0; 444 LIST_REMOVE(snp, snp_list); 445 free(snp->snp_buf, M_SNP); 446 snp->snp_flags &= ~SNOOP_OPEN; 447 dev->si_drv1 = NULL; 448 449 return (snp_detach(snp)); 450 } 451 452 static int 453 snp_down(struct snoop *snp) 454 { 455 456 if (snp->snp_blen != SNOOP_MINLEN) { 457 free(snp->snp_buf, M_SNP); 458 snp->snp_buf = malloc(SNOOP_MINLEN, M_SNP, M_WAITOK); 459 snp->snp_blen = SNOOP_MINLEN; 460 } 461 snp->snp_flags |= SNOOP_DOWN; 462 463 return (snp_detach(snp)); 464 } 465 466 static int 467 snpioctl(dev_t dev, u_long cmd, caddr_t data, int flags, d_thread_t *td) 468 { 469 struct snoop *snp; 470 struct tty *tp, *tpo; 471 dev_t tdev; 472 473 snp = dev->si_drv1; 474 switch (cmd) { 475 case SNPSTTY: 476 tdev = udev2dev(*((udev_t *)data), 0); 477 if (tdev == NODEV) 478 return (snp_down(snp)); 479 480 tp = snpdevtotty(tdev); 481 if (!tp) 482 return (EINVAL); 483 if (tp->t_state & TS_SNOOP) 484 return (EBUSY); 485 486 crit_enter(); 487 488 if (snp->snp_target == NODEV) { 489 tpo = snp->snp_tty; 490 if (tpo) 491 tpo->t_state &= ~TS_SNOOP; 492 } 493 494 tp->t_sc = (caddr_t)snp; 495 tp->t_state |= TS_SNOOP; 496 snp->snp_olddisc = tp->t_line; 497 tp->t_line = snooplinedisc; 498 snp->snp_tty = tp; 499 snp->snp_target = tdev; 500 501 /* 502 * Clean overflow and down flags - 503 * we'll have a chance to get them in the future :))) 504 */ 505 snp->snp_flags &= ~SNOOP_OFLOW; 506 snp->snp_flags &= ~SNOOP_DOWN; 507 crit_exit(); 508 break; 509 510 case SNPGTTY: 511 /* 512 * We keep snp_target field specially to make 513 * SNPGTTY happy, else we can't know what is device 514 * major/minor for tty. 515 */ 516 *((dev_t *)data) = snp->snp_target; 517 break; 518 519 case FIONBIO: 520 break; 521 522 case FIOASYNC: 523 if (*(int *)data) 524 snp->snp_flags |= SNOOP_ASYNC; 525 else 526 snp->snp_flags &= ~SNOOP_ASYNC; 527 break; 528 529 case FIONREAD: 530 crit_enter(); 531 if (snp->snp_tty != NULL) 532 *(int *)data = snp->snp_len; 533 else 534 if (snp->snp_flags & SNOOP_DOWN) { 535 if (snp->snp_flags & SNOOP_OFLOW) 536 *(int *)data = SNP_OFLOW; 537 else 538 *(int *)data = SNP_TTYCLOSE; 539 } else { 540 *(int *)data = SNP_DETACH; 541 } 542 crit_exit(); 543 break; 544 545 default: 546 return (ENOTTY); 547 } 548 return (0); 549 } 550 551 static int 552 snppoll(dev_t dev, int events, d_thread_t *td) 553 { 554 struct snoop *snp; 555 int revents; 556 557 snp = dev->si_drv1; 558 revents = 0; 559 /* 560 * If snoop is down, we don't want to poll() forever so we return 1. 561 * Caller should see if we down via FIONREAD ioctl(). The last should 562 * return -1 to indicate down state. 563 */ 564 if (events & (POLLIN | POLLRDNORM)) { 565 if (snp->snp_flags & SNOOP_DOWN || snp->snp_len > 0) 566 revents |= events & (POLLIN | POLLRDNORM); 567 else 568 selrecord(td, &snp->snp_sel); 569 } 570 return (revents); 571 } 572 573 static int 574 snp_modevent(module_t mod, int type, void *data) 575 { 576 577 switch (type) { 578 case MOD_LOAD: 579 snooplinedisc = ldisc_register(LDISC_LOAD, &snpdisc); 580 cdevsw_add(&snp_cdevsw, 0, 0); 581 break; 582 case MOD_UNLOAD: 583 if (!LIST_EMPTY(&snp_sclist)) 584 return (EBUSY); 585 ldisc_deregister(snooplinedisc); 586 cdevsw_remove(&snp_cdevsw, 0, 0); 587 break; 588 default: 589 break; 590 } 591 return (0); 592 } 593 594 static moduledata_t snp_mod = { 595 "snp", 596 snp_modevent, 597 NULL 598 }; 599 DECLARE_MODULE(snp, snp_mod, SI_SUB_DRIVERS, SI_ORDER_MIDDLE + CDEV_MAJOR); 600