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: head/sys/dev/snp/snp.c 119419 2003-08-24 18:03:45Z obrien $");
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/queue.h>
29#include <sys/snoop.h>
30#include <sys/vnode.h>
31
32static l_close_t snplclose;
33static l_write_t snplwrite;
34static d_open_t snpopen;
35static d_close_t snpclose;
36static d_read_t snpread;
37static d_write_t snpwrite;
38static d_ioctl_t snpioctl;
39static d_poll_t snppoll;
40
41#define CDEV_MAJOR 53
42static struct cdevsw snp_cdevsw = {
43 .d_open = snpopen,
44 .d_close = snpclose,
45 .d_read = snpread,
46 .d_write = snpwrite,
47 .d_ioctl = snpioctl,
48 .d_poll = snppoll,
49 .d_name = "snp",
50 .d_maj = CDEV_MAJOR,
51};
52
53static struct linesw snpdisc = {
54 ttyopen, snplclose, ttread, snplwrite,
55 l_nullioctl, ttyinput, ttstart, ttymodem
56};
57
58/*
59 * This is the main snoop per-device structure.
60 */
61struct snoop {
62 LIST_ENTRY(snoop) snp_list; /* List glue. */
63 int snp_unit; /* Device number. */
64 dev_t snp_target; /* Target tty device. */
65 struct tty *snp_tty; /* Target tty pointer. */
66 u_long snp_len; /* Possible length. */
67 u_long snp_base; /* Data base. */
68 u_long snp_blen; /* Used length. */
69 caddr_t snp_buf; /* Allocation pointer. */
70 int snp_flags; /* Flags. */
71 struct selinfo snp_sel; /* Select info. */
72 int snp_olddisc; /* Old line discipline. */
73};
74
75/*
76 * Possible flags.
77 */
78#define SNOOP_ASYNC 0x0002
79#define SNOOP_OPEN 0x0004
80#define SNOOP_RWAIT 0x0008
81#define SNOOP_OFLOW 0x0010
82#define SNOOP_DOWN 0x0020
83
84/*
85 * Other constants.
86 */
87#define SNOOP_MINLEN (4*1024) /* This should be power of 2.
88 * 4K tested to be the minimum
89 * for which on normal tty
90 * usage there is no need to
91 * allocate more.
92 */
93#define SNOOP_MAXLEN (64*1024) /* This one also,64K enough
94 * If we grow more,something
95 * really bad in this world..
96 */
97
98static MALLOC_DEFINE(M_SNP, "snp", "Snoop device data");
99/*
100 * The number of the "snoop" line discipline. This gets determined at
101 * module load time.
102 */
103static int snooplinedisc;
104static udev_t snpbasedev = NOUDEV;
105
106
107static LIST_HEAD(, snoop) snp_sclist = LIST_HEAD_INITIALIZER(&snp_sclist);
108
109static struct tty *snpdevtotty(dev_t dev);
110static void snp_clone(void *arg, char *name,
111 int namelen, dev_t *dev);
112static int snp_detach(struct snoop *snp);
113static int snp_down(struct snoop *snp);
114static int snp_in(struct snoop *snp, char *buf, int n);
115static int snp_modevent(module_t mod, int what, void *arg);
116
117static int
118snplclose(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
133static int
134snplwrite(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
176static struct tty *
177snpdevtotty(dev)
178 dev_t 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
193static int
194snpwrite(dev, uio, flag)
195 dev_t 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
215tty_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
232static int
233snpread(dev, uio, flag)
234 dev_t 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
298static int
299snp_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 selwakeup(&snp->snp_sel);
374
375 return (n);
376}
377
378static int
379snpopen(dev, flag, mode, td)
380 dev_t dev;
381 int flag, mode;
382 struct thread *td;
383{
384 struct snoop *snp;
385
386 if (dev->si_drv1 == NULL) {
387 if (!(dev->si_flags & SI_NAMED))
388 make_dev(&snp_cdevsw, minor(dev), UID_ROOT, GID_WHEEL,
389 0600, "snp%d", dev2unit(dev));
390 dev->si_drv1 = snp = malloc(sizeof(*snp), M_SNP,
391 M_WAITOK | M_ZERO);
392 snp->snp_unit = dev2unit(dev);
393 } else
394 return (EBUSY);
395
396 /*
397 * We intentionally do not OR flags with SNOOP_OPEN, but set them so
398 * all previous settings (especially SNOOP_OFLOW) will be cleared.
399 */
400 snp->snp_flags = SNOOP_OPEN;
401
402 snp->snp_buf = malloc(SNOOP_MINLEN, M_SNP, M_WAITOK);
403 snp->snp_blen = SNOOP_MINLEN;
404 snp->snp_base = 0;
405 snp->snp_len = 0;
406
407 /*
408 * snp_tty == NULL is for inactive snoop devices.
409 */
410 snp->snp_tty = NULL;
411 snp->snp_target = NODEV;
412
413 LIST_INSERT_HEAD(&snp_sclist, snp, snp_list);
414 return (0);
415}
416
417
418static int
419snp_detach(snp)
420 struct snoop *snp;
421{
422 struct tty *tp;
423
424 snp->snp_base = 0;
425 snp->snp_len = 0;
426
427 /*
428 * If line disc. changed we do not touch this pointer, SLIP/PPP will
429 * change it anyway.
430 */
431 tp = snp->snp_tty;
432 if (tp == NULL)
433 goto detach_notty;
434
435 if (tp && (tp->t_sc == snp) && (tp->t_state & TS_SNOOP) &&
436 tp->t_line == snooplinedisc) {
437 tp->t_sc = NULL;
438 tp->t_state &= ~TS_SNOOP;
439 tp->t_line = snp->snp_olddisc;
440 } else
441 printf("snp%d: bad attached tty data\n", snp->snp_unit);
442
443 snp->snp_tty = NULL;
444 snp->snp_target = NODEV;
445
446detach_notty:
447 selwakeup(&snp->snp_sel);
448 if ((snp->snp_flags & SNOOP_OPEN) == 0)
449 free(snp, M_SNP);
450
451 return (0);
452}
453
454static int
455snpclose(dev, flags, fmt, td)
456 dev_t dev;
457 int flags;
458 int fmt;
459 struct thread *td;
460{
461 struct snoop *snp;
462
463 snp = dev->si_drv1;
464 snp->snp_blen = 0;
465 LIST_REMOVE(snp, snp_list);
466 free(snp->snp_buf, M_SNP);
467 snp->snp_flags &= ~SNOOP_OPEN;
468 dev->si_drv1 = NULL;
469
470 return (snp_detach(snp));
471}
472
473static int
474snp_down(snp)
475 struct snoop *snp;
476{
477
478 if (snp->snp_blen != SNOOP_MINLEN) {
479 free(snp->snp_buf, M_SNP);
480 snp->snp_buf = malloc(SNOOP_MINLEN, M_SNP, M_WAITOK);
481 snp->snp_blen = SNOOP_MINLEN;
482 }
483 snp->snp_flags |= SNOOP_DOWN;
484
485 return (snp_detach(snp));
486}
487
488static int
489snpioctl(dev, cmd, data, flags, td)
490 dev_t dev;
491 u_long cmd;
492 caddr_t data;
493 int flags;
494 struct thread *td;
495{
496 struct snoop *snp;
497 struct tty *tp, *tpo;
498 dev_t tdev;
499 int s;
500
501 snp = dev->si_drv1;
502 switch (cmd) {
503 case SNPSTTY:
504 tdev = udev2dev(*((udev_t *)data), 0);
505 if (tdev == NODEV)
506 return (snp_down(snp));
507
508 tp = snpdevtotty(tdev);
509 if (!tp)
510 return (EINVAL);
511 if (tp->t_state & TS_SNOOP)
512 return (EBUSY);
513
514 s = spltty();
515
516 if (snp->snp_target == NODEV) {
517 tpo = snp->snp_tty;
518 if (tpo)
519 tpo->t_state &= ~TS_SNOOP;
520 }
521
522 tp->t_sc = (caddr_t)snp;
523 tp->t_state |= TS_SNOOP;
524 snp->snp_olddisc = tp->t_line;
525 tp->t_line = snooplinedisc;
526 snp->snp_tty = tp;
527 snp->snp_target = tdev;
528
529 /*
530 * Clean overflow and down flags -
531 * we'll have a chance to get them in the future :)))
532 */
533 snp->snp_flags &= ~SNOOP_OFLOW;
534 snp->snp_flags &= ~SNOOP_DOWN;
535 splx(s);
536 break;
537
538 case SNPGTTY:
539 /*
540 * We keep snp_target field specially to make
541 * SNPGTTY happy, else we can't know what is device
542 * major/minor for tty.
543 */
544 *((udev_t *)data) = dev2udev(snp->snp_target);
545 break;
546
547 case FIONBIO:
548 break;
549
550 case FIOASYNC:
551 if (*(int *)data)
552 snp->snp_flags |= SNOOP_ASYNC;
553 else
554 snp->snp_flags &= ~SNOOP_ASYNC;
555 break;
556
557 case FIONREAD:
558 s = spltty();
559 if (snp->snp_tty != NULL)
560 *(int *)data = snp->snp_len;
561 else
562 if (snp->snp_flags & SNOOP_DOWN) {
563 if (snp->snp_flags & SNOOP_OFLOW)
564 *(int *)data = SNP_OFLOW;
565 else
566 *(int *)data = SNP_TTYCLOSE;
567 } else {
568 *(int *)data = SNP_DETACH;
569 }
570 splx(s);
571 break;
572
573 default:
574 return (ENOTTY);
575 }
576 return (0);
577}
578
579static int
580snppoll(dev, events, td)
581 dev_t dev;
582 int events;
583 struct thread *td;
584{
585 struct snoop *snp;
586 int revents;
587
588 snp = dev->si_drv1;
589 revents = 0;
590 /*
591 * If snoop is down, we don't want to poll() forever so we return 1.
592 * Caller should see if we down via FIONREAD ioctl(). The last should
593 * return -1 to indicate down state.
594 */
595 if (events & (POLLIN | POLLRDNORM)) {
596 if (snp->snp_flags & SNOOP_DOWN || snp->snp_len > 0)
597 revents |= events & (POLLIN | POLLRDNORM);
598 else
599 selrecord(td, &snp->snp_sel);
600 }
601 return (revents);
602}
603
604static void
605snp_clone(arg, name, namelen, dev)
606 void *arg;
607 char *name;
608 int namelen;
609 dev_t *dev;
610{
611 int u;
612
613 if (*dev != NODEV)
614 return;
615 if (dev_stdclone(name, NULL, "snp", &u) != 1)
616 return;
617 *dev = make_dev(&snp_cdevsw, unit2minor(u), UID_ROOT, GID_WHEEL, 0600,
618 "snp%d", u);
619 if (snpbasedev == NOUDEV)
620 snpbasedev = (*dev)->si_udev;
621 else {
622 (*dev)->si_flags |= SI_CHEAPCLONE;
623 dev_depends(udev2dev(snpbasedev, 0), *dev);
624 }
625}
626
627static int
628snp_modevent(mod, type, data)
629 module_t mod;
630 int type;
631 void *data;
632{
633 static eventhandler_tag eh_tag;
634
635 switch (type) {
636 case MOD_LOAD:
637 /* XXX error checking. */
638 eh_tag = EVENTHANDLER_REGISTER(dev_clone, snp_clone, 0, 1000);
639 snooplinedisc = ldisc_register(LDISC_LOAD, &snpdisc);
640 break;
641 case MOD_UNLOAD:
642 if (!LIST_EMPTY(&snp_sclist))
643 return (EBUSY);
644 EVENTHANDLER_DEREGISTER(dev_clone, eh_tag);
645 if (snpbasedev != NOUDEV)
646 destroy_dev(udev2dev(snpbasedev, 0));
647 ldisc_deregister(snooplinedisc);
648 break;
649 default:
650 break;
651 }
652 return (0);
653}
654
655static moduledata_t snp_mod = {
656 "snp",
657 snp_modevent,
658 NULL
659};
660DECLARE_MODULE(snp, snp_mod, SI_SUB_DRIVERS, SI_ORDER_MIDDLE + CDEV_MAJOR);