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 1.19 2007/05/08 02:31:41 dillon Exp $ 17 */ 18 19 #include "use_snp.h" 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/event.h> 27 #include <sys/kernel.h> 28 #include <sys/queue.h> 29 #include <sys/snoop.h> 30 #include <sys/thread2.h> 31 #include <sys/vnode.h> 32 #include <sys/device.h> 33 #include <sys/devfs.h> 34 35 static l_close_t snplclose; 36 static l_write_t snplwrite; 37 static d_open_t snpopen; 38 static d_close_t snpclose; 39 static d_read_t snpread; 40 static d_write_t snpwrite; 41 static d_ioctl_t snpioctl; 42 static d_kqfilter_t snpkqfilter; 43 static d_clone_t snpclone; 44 DEVFS_DECLARE_CLONE_BITMAP(snp); 45 46 static void snpfilter_detach(struct knote *); 47 static int snpfilter_rd(struct knote *, long); 48 static int snpfilter_wr(struct knote *, long); 49 50 #if NSNP <= 1 51 #define SNP_PREALLOCATED_UNITS 4 52 #else 53 #define SNP_PREALLOCATED_UNITS NSNP 54 #endif 55 56 #define CDEV_MAJOR 53 57 static struct dev_ops snp_ops = { 58 { "snp", CDEV_MAJOR, D_KQFILTER }, 59 .d_open = snpopen, 60 .d_close = snpclose, 61 .d_read = snpread, 62 .d_write = snpwrite, 63 .d_ioctl = snpioctl, 64 .d_kqfilter = snpkqfilter 65 }; 66 67 static struct linesw snpdisc = { 68 ttyopen, snplclose, ttread, snplwrite, 69 l_nullioctl, ttyinput, ttstart, ttymodem 70 }; 71 72 /* 73 * This is the main snoop per-device structure. 74 */ 75 struct snoop { 76 LIST_ENTRY(snoop) snp_list; /* List glue. */ 77 cdev_t snp_target; /* Target tty device. */ 78 struct tty *snp_tty; /* Target tty pointer. */ 79 u_long snp_len; /* Possible length. */ 80 u_long snp_base; /* Data base. */ 81 u_long snp_blen; /* Used length. */ 82 caddr_t snp_buf; /* Allocation pointer. */ 83 int snp_flags; /* Flags. */ 84 struct kqinfo snp_kq; /* Kqueue info. */ 85 int snp_olddisc; /* Old line discipline. */ 86 }; 87 88 /* 89 * Possible flags. 90 */ 91 #define SNOOP_ASYNC 0x0002 92 #define SNOOP_OPEN 0x0004 93 #define SNOOP_RWAIT 0x0008 94 #define SNOOP_OFLOW 0x0010 95 #define SNOOP_DOWN 0x0020 96 97 /* 98 * Other constants. 99 */ 100 #define SNOOP_MINLEN (4*1024) /* This should be power of 2. 101 * 4K tested to be the minimum 102 * for which on normal tty 103 * usage there is no need to 104 * allocate more. 105 */ 106 #define SNOOP_MAXLEN (64*1024) /* This one also,64K enough 107 * If we grow more,something 108 * really bad in this world.. 109 */ 110 111 static MALLOC_DEFINE(M_SNP, "snp", "Snoop device data"); 112 /* 113 * The number of the "snoop" line discipline. This gets determined at 114 * module load time. 115 */ 116 static int snooplinedisc; 117 118 119 static LIST_HEAD(, snoop) snp_sclist = LIST_HEAD_INITIALIZER(&snp_sclist); 120 121 static struct tty *snpdevtotty (cdev_t dev); 122 static int snp_detach (struct snoop *snp); 123 static int snp_down (struct snoop *snp); 124 static int snp_in (struct snoop *snp, char *buf, int n); 125 static int snp_modevent (module_t mod, int what, void *arg); 126 127 static int 128 snplclose(struct tty *tp, int flag) 129 { 130 struct snoop *snp; 131 int error; 132 133 snp = tp->t_sc; 134 error = snp_down(snp); 135 if (error != 0) 136 return (error); 137 error = ttylclose(tp, flag); 138 return (error); 139 } 140 141 static int 142 snplwrite(struct tty *tp, struct uio *uio, 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 = (int)szmin(512, uio->uio_resid); 155 ibuf = kmalloc(ilen, M_SNP, M_WAITOK); 156 error = uiomove(ibuf, (size_t)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 kfree(ibuf, M_SNP); 174 ibuf = NULL; 175 } 176 if (ibuf != NULL) 177 kfree(ibuf, M_SNP); 178 return (error); 179 } 180 181 static struct tty * 182 snpdevtotty(cdev_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(struct dev_write_args *ap) 196 { 197 cdev_t dev = ap->a_head.a_dev; 198 struct uio *uio = ap->a_uio; 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 kprintf("Snoop: attempt to write to bad tty.\n"); 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 = (int)szmin(uio->uio_resid, SNP_INPUT_BUF); 221 if ((error = uiomove(c, (size_t)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(struct dev_read_args *ap) 234 { 235 cdev_t dev = ap->a_head.a_dev; 236 struct uio *uio = ap->a_uio; 237 struct snoop *snp; 238 int error, len, n, nblen; 239 caddr_t from; 240 char *nbuf; 241 242 snp = dev->si_drv1; 243 KASSERT(snp->snp_len + snp->snp_base <= snp->snp_blen, 244 ("snoop buffer error")); 245 246 if (snp->snp_tty == NULL) 247 return (EIO); 248 249 snp->snp_flags &= ~SNOOP_RWAIT; 250 251 do { 252 if (snp->snp_len == 0) { 253 if (ap->a_ioflag & IO_NDELAY) 254 return (EWOULDBLOCK); 255 snp->snp_flags |= SNOOP_RWAIT; 256 error = tsleep((caddr_t)snp, PCATCH, "snprd", 0); 257 if (error != 0) 258 return (error); 259 } 260 } while (snp->snp_len == 0); 261 262 n = snp->snp_len; 263 264 error = 0; 265 while (snp->snp_len > 0 && uio->uio_resid > 0 && error == 0) { 266 len = (int)szmin(uio->uio_resid, snp->snp_len); 267 from = (caddr_t)(snp->snp_buf + snp->snp_base); 268 if (len == 0) 269 break; 270 271 error = uiomove(from, (size_t)len, uio); 272 snp->snp_base += len; 273 snp->snp_len -= len; 274 } 275 if ((snp->snp_flags & SNOOP_OFLOW) && (n < snp->snp_len)) { 276 snp->snp_flags &= ~SNOOP_OFLOW; 277 } 278 crit_enter(); 279 nblen = snp->snp_blen; 280 if (((nblen / 2) >= SNOOP_MINLEN) && (nblen / 2) >= snp->snp_len) { 281 while (nblen / 2 >= snp->snp_len && nblen / 2 >= SNOOP_MINLEN) 282 nblen = nblen / 2; 283 if ((nbuf = kmalloc(nblen, M_SNP, M_NOWAIT)) != NULL) { 284 bcopy(snp->snp_buf + snp->snp_base, nbuf, snp->snp_len); 285 kfree(snp->snp_buf, M_SNP); 286 snp->snp_buf = nbuf; 287 snp->snp_blen = nblen; 288 snp->snp_base = 0; 289 } 290 } 291 crit_exit(); 292 293 return (error); 294 } 295 296 static int 297 snp_in(struct snoop *snp, char *buf, int n) 298 { 299 int s_free, s_tail; 300 int len, nblen; 301 caddr_t from, to; 302 char *nbuf; 303 304 KASSERT(n >= 0, ("negative snoop char count")); 305 306 if (n == 0) 307 return (0); 308 309 if (snp->snp_flags & SNOOP_DOWN) { 310 kprintf("Snoop: more data to down interface.\n"); 311 return (0); 312 } 313 314 if (snp->snp_flags & SNOOP_OFLOW) { 315 kprintf("Snoop: buffer overflow.\n"); 316 /* 317 * On overflow we just repeat the standart close 318 * procedure...yes , this is waste of space but.. Then next 319 * read from device will fail if one would recall he is 320 * snooping and retry... 321 */ 322 323 return (snp_down(snp)); 324 } 325 s_tail = snp->snp_blen - (snp->snp_len + snp->snp_base); 326 s_free = snp->snp_blen - snp->snp_len; 327 328 329 if (n > s_free) { 330 crit_enter(); 331 nblen = snp->snp_blen; 332 while ((n > s_free) && ((nblen * 2) <= SNOOP_MAXLEN)) { 333 nblen = snp->snp_blen * 2; 334 s_free = nblen - (snp->snp_len + snp->snp_base); 335 } 336 if ((n <= s_free) && (nbuf = kmalloc(nblen, M_SNP, M_NOWAIT))) { 337 bcopy(snp->snp_buf + snp->snp_base, nbuf, snp->snp_len); 338 kfree(snp->snp_buf, M_SNP); 339 snp->snp_buf = nbuf; 340 snp->snp_blen = nblen; 341 snp->snp_base = 0; 342 } else { 343 snp->snp_flags |= SNOOP_OFLOW; 344 if (snp->snp_flags & SNOOP_RWAIT) { 345 snp->snp_flags &= ~SNOOP_RWAIT; 346 wakeup((caddr_t)snp); 347 } 348 crit_exit(); 349 return (0); 350 } 351 crit_exit(); 352 } 353 if (n > s_tail) { 354 from = (caddr_t)(snp->snp_buf + snp->snp_base); 355 to = (caddr_t)(snp->snp_buf); 356 len = snp->snp_len; 357 bcopy(from, to, len); 358 snp->snp_base = 0; 359 } 360 to = (caddr_t)(snp->snp_buf + snp->snp_base + snp->snp_len); 361 bcopy(buf, to, n); 362 snp->snp_len += n; 363 364 if (snp->snp_flags & SNOOP_RWAIT) { 365 snp->snp_flags &= ~SNOOP_RWAIT; 366 wakeup((caddr_t)snp); 367 } 368 KNOTE(&snp->snp_kq.ki_note, 0); 369 370 return (n); 371 } 372 373 static int 374 snpopen(struct dev_open_args *ap) 375 { 376 cdev_t dev = ap->a_head.a_dev; 377 struct snoop *snp; 378 379 if (dev->si_drv1 == NULL) { 380 #if 0 381 make_dev(&snp_ops, minor(dev), UID_ROOT, GID_WHEEL, 382 0600, "snp%d", minor(dev)); 383 #endif 384 dev->si_drv1 = snp = kmalloc(sizeof(*snp), M_SNP, 385 M_WAITOK | M_ZERO); 386 } else { 387 return (EBUSY); 388 } 389 390 /* 391 * We intentionally do not OR flags with SNOOP_OPEN, but set them so 392 * all previous settings (especially SNOOP_OFLOW) will be cleared. 393 */ 394 snp->snp_flags = SNOOP_OPEN; 395 396 snp->snp_buf = kmalloc(SNOOP_MINLEN, M_SNP, M_WAITOK); 397 snp->snp_blen = SNOOP_MINLEN; 398 snp->snp_base = 0; 399 snp->snp_len = 0; 400 401 /* 402 * snp_tty == NULL is for inactive snoop devices. 403 */ 404 snp->snp_tty = NULL; 405 snp->snp_target = NULL; 406 407 LIST_INSERT_HEAD(&snp_sclist, snp, snp_list); 408 return (0); 409 } 410 411 412 static int 413 snp_detach(struct snoop *snp) 414 { 415 struct tty *tp; 416 417 snp->snp_base = 0; 418 snp->snp_len = 0; 419 420 /* 421 * If line disc. changed we do not touch this pointer, SLIP/PPP will 422 * change it anyway. 423 */ 424 tp = snp->snp_tty; 425 if (tp == NULL) 426 goto detach_notty; 427 428 if (tp && (tp->t_sc == snp) && (tp->t_state & TS_SNOOP) && 429 tp->t_line == snooplinedisc) { 430 tp->t_sc = NULL; 431 tp->t_state &= ~TS_SNOOP; 432 tp->t_line = snp->snp_olddisc; 433 } else 434 kprintf("Snoop: bad attached tty data.\n"); 435 436 snp->snp_tty = NULL; 437 snp->snp_target = NULL; 438 439 detach_notty: 440 KNOTE(&snp->snp_kq.ki_note, 0); 441 if ((snp->snp_flags & SNOOP_OPEN) == 0) 442 kfree(snp, M_SNP); 443 444 return (0); 445 } 446 447 static int 448 snpclose(struct dev_close_args *ap) 449 { 450 cdev_t dev = ap->a_head.a_dev; 451 struct snoop *snp; 452 453 snp = dev->si_drv1; 454 snp->snp_blen = 0; 455 LIST_REMOVE(snp, snp_list); 456 kfree(snp->snp_buf, M_SNP); 457 snp->snp_flags &= ~SNOOP_OPEN; 458 dev->si_drv1 = NULL; 459 if (dev->si_uminor >= SNP_PREALLOCATED_UNITS) { 460 devfs_clone_bitmap_put(&DEVFS_CLONE_BITMAP(snp), dev->si_uminor); 461 destroy_dev(dev); 462 } 463 return (snp_detach(snp)); 464 } 465 466 static int 467 snp_down(struct snoop *snp) 468 { 469 470 if (snp->snp_blen != SNOOP_MINLEN) { 471 kfree(snp->snp_buf, M_SNP); 472 snp->snp_buf = kmalloc(SNOOP_MINLEN, M_SNP, M_WAITOK); 473 snp->snp_blen = SNOOP_MINLEN; 474 } 475 snp->snp_flags |= SNOOP_DOWN; 476 477 return (snp_detach(snp)); 478 } 479 480 static int 481 snpioctl(struct dev_ioctl_args *ap) 482 { 483 cdev_t dev = ap->a_head.a_dev; 484 struct snoop *snp; 485 struct tty *tp, *tpo; 486 cdev_t tdev; 487 488 snp = dev->si_drv1; 489 switch (ap->a_cmd) { 490 case SNPSTTY: 491 tdev = udev2dev(*((udev_t *)ap->a_data), 0); 492 if (tdev == NULL) 493 return (snp_down(snp)); 494 495 tp = snpdevtotty(tdev); 496 if (!tp) 497 return (EINVAL); 498 if (tp->t_state & TS_SNOOP) 499 return (EBUSY); 500 501 crit_enter(); 502 503 if (snp->snp_target == NULL) { 504 tpo = snp->snp_tty; 505 if (tpo) 506 tpo->t_state &= ~TS_SNOOP; 507 } 508 509 tp->t_sc = (caddr_t)snp; 510 tp->t_state |= TS_SNOOP; 511 snp->snp_olddisc = tp->t_line; 512 tp->t_line = snooplinedisc; 513 snp->snp_tty = tp; 514 snp->snp_target = tdev; 515 516 /* 517 * Clean overflow and down flags - 518 * we'll have a chance to get them in the future :))) 519 */ 520 snp->snp_flags &= ~SNOOP_OFLOW; 521 snp->snp_flags &= ~SNOOP_DOWN; 522 crit_exit(); 523 break; 524 525 case SNPGTTY: 526 /* 527 * We keep snp_target field specially to make 528 * SNPGTTY happy, else we can't know what is device 529 * major/minor for tty. 530 */ 531 *((cdev_t *)ap->a_data) = snp->snp_target; 532 break; 533 534 case FIOASYNC: 535 if (*(int *)ap->a_data) 536 snp->snp_flags |= SNOOP_ASYNC; 537 else 538 snp->snp_flags &= ~SNOOP_ASYNC; 539 break; 540 541 case FIONREAD: 542 crit_enter(); 543 if (snp->snp_tty != NULL) 544 *(int *)ap->a_data = snp->snp_len; 545 else 546 if (snp->snp_flags & SNOOP_DOWN) { 547 if (snp->snp_flags & SNOOP_OFLOW) 548 *(int *)ap->a_data = SNP_OFLOW; 549 else 550 *(int *)ap->a_data = SNP_TTYCLOSE; 551 } else { 552 *(int *)ap->a_data = SNP_DETACH; 553 } 554 crit_exit(); 555 break; 556 557 default: 558 return (ENOTTY); 559 } 560 return (0); 561 } 562 563 static struct filterops snpfiltops_rd = 564 { FILTEROP_ISFD, NULL, snpfilter_detach, snpfilter_rd }; 565 static struct filterops snpfiltops_wr = 566 { FILTEROP_ISFD, NULL, snpfilter_detach, snpfilter_wr }; 567 568 static int 569 snpkqfilter(struct dev_kqfilter_args *ap) 570 { 571 cdev_t dev = ap->a_head.a_dev; 572 struct snoop *snp = dev->si_drv1; 573 struct knote *kn = ap->a_kn; 574 struct klist *klist; 575 576 ap->a_result = 0; 577 578 switch (kn->kn_filter) { 579 case EVFILT_READ: 580 kn->kn_fop = &snpfiltops_rd; 581 kn->kn_hook = (caddr_t)snp; 582 break; 583 case EVFILT_WRITE: 584 kn->kn_fop = &snpfiltops_wr; 585 kn->kn_hook = (caddr_t)snp; 586 break; 587 default: 588 ap->a_result = EOPNOTSUPP; 589 return (0); 590 } 591 592 klist = &snp->snp_kq.ki_note; 593 knote_insert(klist, kn); 594 595 return (0); 596 } 597 598 static void 599 snpfilter_detach(struct knote *kn) 600 { 601 struct snoop *snp = (struct snoop *)kn->kn_hook; 602 struct klist *klist; 603 604 klist = &snp->snp_kq.ki_note; 605 knote_insert(klist, kn); 606 } 607 608 static int 609 snpfilter_rd(struct knote *kn, long hint) 610 { 611 struct snoop *snp = (struct snoop *)kn->kn_hook; 612 int ready = 0; 613 614 /* 615 * If snoop is down, we don't want to poll forever so we return 1. 616 * Caller should see if we down via FIONREAD ioctl(). The last should 617 * return -1 to indicate down state. 618 */ 619 if (snp->snp_flags & SNOOP_DOWN || snp->snp_len > 0) 620 ready = 1; 621 622 return (ready); 623 } 624 625 static int 626 snpfilter_wr(struct knote *kn, long hint) 627 { 628 /* Writing is always OK */ 629 return (1); 630 } 631 632 static int 633 snpclone(struct dev_clone_args *ap) 634 { 635 int unit; 636 unit = devfs_clone_bitmap_get(&DEVFS_CLONE_BITMAP(snp), 0); 637 ap->a_dev = make_only_dev(&snp_ops, unit, UID_ROOT, GID_WHEEL, 0600, 638 "snp%d", unit); 639 640 return 0; 641 } 642 643 static int 644 snp_modevent(module_t mod, int type, void *data) 645 { 646 int i; 647 648 switch (type) { 649 case MOD_LOAD: 650 snooplinedisc = ldisc_register(LDISC_LOAD, &snpdisc); 651 make_autoclone_dev(&snp_ops, &DEVFS_CLONE_BITMAP(snp), 652 snpclone, UID_ROOT, GID_WHEEL, 0600, "snp"); 653 654 for (i = 0; i < SNP_PREALLOCATED_UNITS; i++) { 655 make_dev(&snp_ops, i, UID_ROOT, GID_WHEEL, 0600, "snp%d", i); 656 devfs_clone_bitmap_set(&DEVFS_CLONE_BITMAP(snp), i); 657 } 658 break; 659 case MOD_UNLOAD: 660 if (!LIST_EMPTY(&snp_sclist)) 661 return (EBUSY); 662 ldisc_deregister(snooplinedisc); 663 devfs_clone_handler_del("snp"); 664 dev_ops_remove_all(&snp_ops); 665 devfs_clone_bitmap_uninit(&DEVFS_CLONE_BITMAP(snp)); 666 break; 667 default: 668 break; 669 } 670 return (0); 671 } 672 673 static moduledata_t snp_mod = { 674 "snp", 675 snp_modevent, 676 NULL 677 }; 678 DECLARE_MODULE(snp, snp_mod, SI_SUB_DRIVERS, SI_ORDER_MIDDLE + CDEV_MAJOR); 679