xref: /illumos-gate/usr/src/uts/common/io/ptem.c (revision 8b80e8cb6855118d46f605e91b5ed4ce83417395)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
23 /*	  All Rights Reserved  	*/
24 
25 
26 /*
27  * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
28  * Use is subject to license terms.
29  */
30 
31 #pragma ident	"%Z%%M%	%I%	%E% SMI" /* from S5R4 1.13 */
32 
33 /*
34  * Description:
35  *
36  * The PTEM streams module is used as a pseudo driver emulator.  Its purpose
37  * is to emulate the ioctl() functions of a terminal device driver.
38  */
39 
40 #include <sys/types.h>
41 #include <sys/param.h>
42 #include <sys/stream.h>
43 #include <sys/stropts.h>
44 #include <sys/strsun.h>
45 #include <sys/termio.h>
46 #include <sys/pcb.h>
47 #include <sys/signal.h>
48 #include <sys/cred.h>
49 #include <sys/strtty.h>
50 #include <sys/errno.h>
51 #include <sys/cmn_err.h>
52 #include <sys/jioctl.h>
53 #include <sys/ptem.h>
54 #include <sys/ptms.h>
55 #include <sys/debug.h>
56 #include <sys/kmem.h>
57 #include <sys/ddi.h>
58 #include <sys/sunddi.h>
59 #include <sys/conf.h>
60 #include <sys/modctl.h>
61 
62 extern struct streamtab pteminfo;
63 
64 static struct fmodsw fsw = {
65 	"ptem",
66 	&pteminfo,
67 	D_MTQPAIR | D_MP
68 };
69 
70 static struct modlstrmod modlstrmod = {
71 	&mod_strmodops, "pty hardware emulator", &fsw
72 };
73 
74 static struct modlinkage modlinkage = {
75 	MODREV_1, &modlstrmod, NULL
76 };
77 
78 int
79 _init()
80 {
81 	return (mod_install(&modlinkage));
82 }
83 
84 int
85 _fini()
86 {
87 	return (mod_remove(&modlinkage));
88 }
89 
90 int
91 _info(struct modinfo *modinfop)
92 {
93 	return (mod_info(&modlinkage, modinfop));
94 }
95 
96 /*
97  * stream data structure definitions
98  */
99 static int ptemopen(queue_t *, dev_t  *, int, int, cred_t *);
100 static int ptemclose(queue_t *, int, cred_t *);
101 static void ptemrput(queue_t *, mblk_t *);
102 static void ptemwput(queue_t *, mblk_t *);
103 static void ptemwsrv(queue_t *);
104 
105 static struct module_info ptem_info = {
106 	0xabcd,
107 	"ptem",
108 	0,
109 	512,
110 	512,
111 	128
112 };
113 
114 static struct qinit ptemrinit = {
115 	(int (*)()) ptemrput,
116 	NULL,
117 	ptemopen,
118 	ptemclose,
119 	NULL,
120 	&ptem_info,
121 	NULL
122 };
123 
124 static struct qinit ptemwinit = {
125 	(int (*)()) ptemwput,
126 	(int (*)()) ptemwsrv,
127 	ptemopen,
128 	ptemclose,
129 	nulldev,
130 	&ptem_info,
131 	NULL
132 };
133 
134 struct streamtab pteminfo = {
135 	&ptemrinit,
136 	&ptemwinit,
137 	NULL,
138 	NULL
139 };
140 
141 static void	ptioc(queue_t *, mblk_t *, int);
142 static int	ptemwmsg(queue_t *, mblk_t *);
143 
144 /*
145  * ptemopen - open routine gets called when the module gets pushed onto the
146  * stream.
147  */
148 /* ARGSUSED */
149 static int
150 ptemopen(
151 	queue_t    *q,		/* pointer to the read side queue */
152 	dev_t   *devp,		/* pointer to stream tail's dev */
153 	int	oflag,		/* the user open(2) supplied flags */
154 	int	sflag,		/* open state flag */
155 	cred_t *credp)		/* credentials */
156 {
157 	struct ptem *ntp;	/* ptem entry for this PTEM module */
158 	mblk_t *mop;		/* an setopts mblk */
159 	struct stroptions *sop;
160 	struct termios *termiosp;
161 	int len;
162 
163 	if (sflag != MODOPEN)
164 		return (EINVAL);
165 
166 	if (q->q_ptr != NULL) {
167 		/* It's already attached. */
168 		return (0);
169 	}
170 
171 	/*
172 	 * Allocate state structure.
173 	 */
174 	ntp = kmem_alloc(sizeof (*ntp), KM_SLEEP);
175 
176 	/*
177 	 * Allocate a message block, used to pass the zero length message for
178 	 * "stty 0".
179 	 *
180 	 * NOTE: it's better to find out if such a message block can be
181 	 *	 allocated before it's needed than to not be able to
182 	 *	 deliver (for possible lack of buffers) when a hang-up
183 	 *	 occurs.
184 	 */
185 	if ((ntp->dack_ptr = allocb(4, BPRI_MED)) == NULL) {
186 		kmem_free(ntp, sizeof (*ntp));
187 		return (EAGAIN);
188 	}
189 
190 	/*
191 	 * Initialize an M_SETOPTS message to set up hi/lo water marks on
192 	 * stream head read queue and add controlling tty if not set.
193 	 */
194 	mop = allocb(sizeof (struct stroptions), BPRI_MED);
195 	if (mop == NULL) {
196 		freemsg(ntp->dack_ptr);
197 		kmem_free(ntp, sizeof (*ntp));
198 		return (EAGAIN);
199 	}
200 	mop->b_datap->db_type = M_SETOPTS;
201 	mop->b_wptr += sizeof (struct stroptions);
202 	sop = (struct stroptions *)mop->b_rptr;
203 	sop->so_flags = SO_HIWAT | SO_LOWAT | SO_ISTTY;
204 	sop->so_hiwat = 512;
205 	sop->so_lowat = 256;
206 
207 	/*
208 	 * Cross-link.
209 	 */
210 	ntp->q_ptr = q;
211 	q->q_ptr = ntp;
212 	WR(q)->q_ptr = ntp;
213 
214 	/*
215 	 * Get termios defaults.  These are stored as
216 	 * a property in the "options" node.
217 	 */
218 	if (ddi_getlongprop(DDI_DEV_T_ANY, ddi_root_node(), 0, "ttymodes",
219 	    (caddr_t)&termiosp, &len) == DDI_PROP_SUCCESS &&
220 	    len == sizeof (struct termios)) {
221 
222 		ntp->cflags = termiosp->c_cflag;
223 		kmem_free(termiosp, len);
224 	} else {
225 		/*
226 		 * Gack!  Whine about it.
227 		 */
228 		cmn_err(CE_WARN, "ptem: Couldn't get ttymodes property!");
229 	}
230 	ntp->wsz.ws_row = 0;
231 	ntp->wsz.ws_col = 0;
232 	ntp->wsz.ws_xpixel = 0;
233 	ntp->wsz.ws_ypixel = 0;
234 
235 	ntp->state = 0;
236 
237 	/*
238 	 * Commit to the open and send the M_SETOPTS off to the stream head.
239 	 */
240 	qprocson(q);
241 	putnext(q, mop);
242 
243 	return (0);
244 }
245 
246 
247 /*
248  * ptemclose - This routine gets called when the module gets popped off of the
249  * stream.
250  */
251 /* ARGSUSED */
252 static int
253 ptemclose(queue_t *q, int flag, cred_t *credp)
254 {
255 	struct ptem *ntp;	/* ptem entry for this PTEM module */
256 
257 	qprocsoff(q);
258 	ntp = (struct ptem *)q->q_ptr;
259 	freemsg(ntp->dack_ptr);
260 	kmem_free(ntp, sizeof (*ntp));
261 	q->q_ptr = WR(q)->q_ptr = NULL;
262 	return (0);
263 }
264 
265 
266 /*
267  * ptemrput - Module read queue put procedure.
268  *
269  * This is called from the module or driver downstream.
270  */
271 static void
272 ptemrput(queue_t *q, mblk_t *mp)
273 {
274 	struct iocblk *iocp;	/* M_IOCTL data */
275 	struct copyresp *resp;	/* transparent ioctl response struct */
276 	int error;
277 
278 	switch (mp->b_datap->db_type) {
279 	case M_DELAY:
280 	case M_READ:
281 		freemsg(mp);
282 		break;
283 
284 	case M_IOCTL:
285 		iocp = (struct iocblk *)mp->b_rptr;
286 
287 		switch (iocp->ioc_cmd) {
288 		case TCSBRK:
289 			/*
290 			 * Send a break message upstream.
291 			 *
292 			 * XXX:	Shouldn't the argument come into play in
293 			 *	determining whether or not so send an M_BREAK?
294 			 *	It certainly does in the write-side direction.
295 			 */
296 			error = miocpullup(mp, sizeof (int));
297 			if (error != 0) {
298 				miocnak(q, mp, 0, error);
299 				break;
300 			}
301 			if (!(*(int *)mp->b_cont->b_rptr)) {
302 				if (!putnextctl(q, M_BREAK)) {
303 					/*
304 					 * Send an NAK reply back
305 					 */
306 					miocnak(q, mp, 0, EAGAIN);
307 					break;
308 				}
309 			}
310 			/*
311 			 * ACK it.
312 			 */
313 			mioc2ack(mp, NULL, 0, 0);
314 			qreply(q, mp);
315 			break;
316 
317 		case JWINSIZE:
318 		case TIOCGWINSZ:
319 		case TIOCSWINSZ:
320 			ptioc(q, mp, RDSIDE);
321 			break;
322 
323 		case TIOCSIGNAL:
324 			/*
325 			 * The following subtle logic is due to the fact that
326 			 * `mp' may be in any one of three distinct formats:
327 			 *
328 			 *	1. A transparent M_IOCTL with an intptr_t-sized
329 			 *	   payload containing the signal number.
330 			 *
331 			 *	2. An I_STR M_IOCTL with an int-sized payload
332 			 *	   containing the signal number.
333 			 *
334 			 *	3. An M_IOCDATA with an int-sized payload
335 			 *	   containing the signal number.
336 			 */
337 			if (iocp->ioc_count == TRANSPARENT) {
338 				intptr_t sig = *(intptr_t *)mp->b_cont->b_rptr;
339 
340 				if (sig < 1 || sig >= NSIG) {
341 					/*
342 					 * it's transparent with pointer
343 					 * to the arg
344 					 */
345 					mcopyin(mp, NULL, sizeof (int), NULL);
346 					qreply(q, mp);
347 					break;
348 				}
349 			}
350 			ptioc(q, mp, RDSIDE);
351 			break;
352 
353 		case TIOCREMOTE:
354 			if (iocp->ioc_count != TRANSPARENT)
355 				ptioc(q, mp, RDSIDE);
356 			else {
357 				mcopyin(mp, NULL, sizeof (int), NULL);
358 				qreply(q, mp);
359 			}
360 			break;
361 
362 		default:
363 			putnext(q, mp);
364 			break;
365 		}
366 		break;
367 
368 	case M_IOCDATA:
369 		resp = (struct copyresp *)mp->b_rptr;
370 		if (resp->cp_rval) {
371 			/*
372 			 * Just free message on failure.
373 			 */
374 			freemsg(mp);
375 			break;
376 		}
377 
378 		/*
379 		 * Only need to copy data for the SET case.
380 		 */
381 		switch (resp->cp_cmd) {
382 
383 		case TIOCSWINSZ:
384 		case TIOCSIGNAL:
385 		case TIOCREMOTE:
386 			ptioc(q, mp, RDSIDE);
387 			break;
388 
389 		case JWINSIZE:
390 		case TIOCGWINSZ:
391 			mp->b_datap->db_type = M_IOCACK;
392 			mioc2ack(mp, NULL, 0, 0);
393 			qreply(q, mp);
394 			break;
395 
396 		default:
397 			freemsg(mp);
398 			break;
399 	}
400 	break;
401 
402 	case M_IOCACK:
403 	case M_IOCNAK:
404 		/*
405 		 * We only pass write-side ioctls through to the master that
406 		 * we've already ACKed or NAKed to the stream head.  Thus, we
407 		 * discard ones arriving from below, since they're redundant
408 		 * from the point of view of modules above us.
409 		 */
410 		freemsg(mp);
411 		break;
412 
413 	case M_HANGUP:
414 		/*
415 		 * clear blocked state.
416 		 */
417 		{
418 			struct ptem *ntp = (struct ptem *)q->q_ptr;
419 			if (ntp->state & OFLOW_CTL) {
420 				ntp->state &= ~OFLOW_CTL;
421 				qenable(WR(q));
422 			}
423 		}
424 	default:
425 		putnext(q, mp);
426 		break;
427 	}
428 }
429 
430 
431 /*
432  * ptemwput - Module write queue put procedure.
433  *
434  * This is called from the module or stream head upstream.
435  *
436  * XXX:	This routine is quite lazy about handling allocation failures,
437  *	basically just giving up and reporting failure.  It really ought to
438  *	set up bufcalls and only fail when it's absolutely necessary.
439  */
440 static void
441 ptemwput(queue_t *q, mblk_t *mp)
442 {
443 	struct ptem *ntp = (struct ptem *)q->q_ptr;
444 	struct iocblk *iocp;	/* outgoing ioctl structure */
445 	struct copyresp *resp;
446 	unsigned char type = mp->b_datap->db_type;
447 
448 	if (type >= QPCTL) {
449 		switch (type) {
450 
451 		case M_IOCDATA:
452 			resp = (struct copyresp *)mp->b_rptr;
453 			if (resp->cp_rval) {
454 				/*
455 				 * Just free message on failure.
456 				 */
457 				freemsg(mp);
458 				break;
459 			}
460 
461 			/*
462 			 * Only need to copy data for the SET case.
463 			 */
464 			switch (resp->cp_cmd) {
465 
466 				case TIOCSWINSZ:
467 					ptioc(q, mp, WRSIDE);
468 					break;
469 
470 				case JWINSIZE:
471 				case TIOCGWINSZ:
472 					mioc2ack(mp, NULL, 0, 0);
473 					qreply(q, mp);
474 					break;
475 
476 				default:
477 					freemsg(mp);
478 			}
479 			break;
480 
481 		case M_FLUSH:
482 			if (*mp->b_rptr & FLUSHW) {
483 			    if ((ntp->state & IS_PTSTTY) &&
484 					(*mp->b_rptr & FLUSHBAND))
485 				flushband(q, *(mp->b_rptr + 1), FLUSHDATA);
486 			    else
487 				flushq(q, FLUSHDATA);
488 			}
489 			putnext(q, mp);
490 			break;
491 
492 		case M_READ:
493 			freemsg(mp);
494 			break;
495 
496 		case M_STOP:
497 			/*
498 			 * Set the output flow control state.
499 			 */
500 			ntp->state |= OFLOW_CTL;
501 			putnext(q, mp);
502 			break;
503 
504 		case M_START:
505 			/*
506 			 * Relieve the output flow control state.
507 			 */
508 			ntp->state &= ~OFLOW_CTL;
509 			putnext(q, mp);
510 			qenable(q);
511 			break;
512 		default:
513 			putnext(q, mp);
514 			break;
515 		}
516 		return;
517 	}
518 	/*
519 	 * If our queue is nonempty or flow control persists
520 	 * downstream or module in stopped state, queue this message.
521 	 */
522 	if (q->q_first != NULL || !bcanputnext(q, mp->b_band)) {
523 		/*
524 		 * Exception: ioctls, except for those defined to
525 		 * take effect after output has drained, should be
526 		 * processed immediately.
527 		 */
528 		switch (type) {
529 
530 		case M_IOCTL:
531 			iocp = (struct iocblk *)mp->b_rptr;
532 			switch (iocp->ioc_cmd) {
533 			/*
534 			 * Queue these.
535 			 */
536 			case TCSETSW:
537 			case TCSETSF:
538 			case TCSETAW:
539 			case TCSETAF:
540 			case TCSBRK:
541 				break;
542 
543 			/*
544 			 * Handle all others immediately.
545 			 */
546 			default:
547 				(void) ptemwmsg(q, mp);
548 				return;
549 			}
550 			break;
551 
552 		case M_DELAY: /* tty delays not supported */
553 			freemsg(mp);
554 			return;
555 
556 		case M_DATA:
557 			if ((mp->b_wptr - mp->b_rptr) < 0) {
558 				/*
559 				 * Free all bad length messages.
560 				 */
561 				freemsg(mp);
562 				return;
563 			} else if ((mp->b_wptr - mp->b_rptr) == 0) {
564 				if (!(ntp->state & IS_PTSTTY)) {
565 					freemsg(mp);
566 					return;
567 				}
568 			}
569 		}
570 		(void) putq(q, mp);
571 		return;
572 	}
573 	/*
574 	 * fast path into ptemwmsg to dispose of mp.
575 	 */
576 	if (!ptemwmsg(q, mp))
577 		(void) putq(q, mp);
578 }
579 
580 /*
581  * ptem write queue service procedure.
582  */
583 static void
584 ptemwsrv(queue_t *q)
585 {
586 	mblk_t *mp;
587 
588 	while ((mp = getq(q)) != NULL) {
589 		if (!bcanputnext(q, mp->b_band) || !ptemwmsg(q, mp)) {
590 			(void) putbq(q, mp);
591 			break;
592 		}
593 	}
594 }
595 
596 
597 /*
598  * This routine is called from both ptemwput and ptemwsrv to do the
599  * actual work of dealing with mp.  ptmewput will have already
600  * dealt with high priority messages.
601  *
602  * Return 1 if the message was processed completely and 0 if not.
603  */
604 static int
605 ptemwmsg(queue_t *q, mblk_t *mp)
606 {
607 	struct ptem *ntp = (struct ptem *)q->q_ptr;
608 	struct iocblk *iocp;	/* outgoing ioctl structure */
609 	struct termio *termiop;
610 	struct termios *termiosp;
611 	mblk_t *dack_ptr;		/* disconnect message ACK block */
612 	mblk_t *pckt_msgp;		/* message sent to the PCKT module */
613 	mblk_t *dp;			/* ioctl reply data */
614 	tcflag_t cflags;
615 	int error;
616 
617 	switch (mp->b_datap->db_type) {
618 
619 	case M_IOCTL:
620 		/*
621 		 * Note:  for each "set" type operation a copy
622 		 * of the M_IOCTL message is made and passed
623 		 * downstream.  Eventually the PCKT module, if
624 		 * it has been pushed, should pick up this message.
625 		 * If the PCKT module has not been pushed the master
626 		 * side stream head will free it.
627 		 */
628 		iocp = (struct iocblk *)mp->b_rptr;
629 		switch (iocp->ioc_cmd) {
630 
631 		case TCSETAF:
632 		case TCSETSF:
633 			/*
634 			 * Flush the read queue.
635 			 */
636 			if (putnextctl1(q, M_FLUSH, FLUSHR) == 0) {
637 				miocnak(q, mp, 0, EAGAIN);
638 				break;
639 			}
640 			/* FALLTHROUGH */
641 
642 		case TCSETA:
643 		case TCSETAW:
644 		case TCSETS:
645 		case TCSETSW:
646 
647 			switch (iocp->ioc_cmd) {
648 			case TCSETAF:
649 			case TCSETA:
650 			case TCSETAW:
651 				error = miocpullup(mp, sizeof (struct termio));
652 				if (error != 0) {
653 					miocnak(q, mp, 0, error);
654 					goto out;
655 				}
656 				cflags = ((struct termio *)
657 				    mp->b_cont->b_rptr)->c_cflag;
658 				ntp->cflags =
659 				    (ntp->cflags & 0xffff0000 | cflags);
660 				break;
661 
662 			case TCSETSF:
663 			case TCSETS:
664 			case TCSETSW:
665 				error = miocpullup(mp, sizeof (struct termios));
666 				if (error != 0) {
667 					miocnak(q, mp, 0, error);
668 					goto out;
669 				}
670 				cflags = ((struct termios *)
671 				    mp->b_cont->b_rptr)->c_cflag;
672 				ntp->cflags = cflags;
673 				break;
674 			}
675 
676 			if ((cflags & CBAUD) == B0) {
677 				/*
678 				 * Hang-up: Send a zero length message.
679 				 */
680 				dack_ptr = ntp->dack_ptr;
681 
682 				if (dack_ptr) {
683 					ntp->dack_ptr = NULL;
684 					/*
685 					 * Send a zero length message
686 					 * downstream.
687 					 */
688 					putnext(q, dack_ptr);
689 				}
690 			} else {
691 				/*
692 				 * Make a copy of this message and pass it on
693 				 * to the PCKT module.
694 				 */
695 				if ((pckt_msgp = copymsg(mp)) == NULL) {
696 					miocnak(q, mp, 0, EAGAIN);
697 					break;
698 				}
699 				putnext(q, pckt_msgp);
700 			}
701 			/*
702 			 * Send ACK upstream.
703 			 */
704 			mioc2ack(mp, NULL, 0, 0);
705 			qreply(q, mp);
706 out:
707 			break;
708 
709 		case TCGETA:
710 			dp = allocb(sizeof (struct termio), BPRI_MED);
711 			if (dp == NULL) {
712 				miocnak(q, mp, 0, EAGAIN);
713 				break;
714 			}
715 			termiop = (struct termio *)dp->b_rptr;
716 			termiop->c_cflag = (ushort_t)ntp->cflags;
717 			mioc2ack(mp, dp, sizeof (struct termio), 0);
718 			qreply(q, mp);
719 			break;
720 
721 		case TCGETS:
722 			dp = allocb(sizeof (struct termios), BPRI_MED);
723 			if (dp == NULL) {
724 				miocnak(q, mp, 0, EAGAIN);
725 				break;
726 			}
727 			termiosp = (struct termios *)dp->b_rptr;
728 			termiosp->c_cflag = ntp->cflags;
729 			mioc2ack(mp, dp, sizeof (struct termios), 0);
730 			qreply(q, mp);
731 			break;
732 
733 		case TCSBRK:
734 			error = miocpullup(mp, sizeof (int));
735 			if (error != 0) {
736 				miocnak(q, mp, 0, error);
737 				break;
738 			}
739 
740 			/*
741 			 * Need a copy of this message to pass it on to
742 			 * the PCKT module.
743 			 */
744 			if ((pckt_msgp = copymsg(mp)) == NULL) {
745 				miocnak(q, mp, 0, EAGAIN);
746 				break;
747 			}
748 			/*
749 			 * Send a copy of the M_IOCTL to the PCKT module.
750 			 */
751 			putnext(q, pckt_msgp);
752 
753 			/*
754 			 * TCSBRK meaningful if data part of message is 0
755 			 * cf. termio(7).
756 			 */
757 			if (!(*(int *)mp->b_cont->b_rptr))
758 				(void) putnextctl(q, M_BREAK);
759 			/*
760 			 * ACK the ioctl.
761 			 */
762 			mioc2ack(mp, NULL, 0, 0);
763 			qreply(q, mp);
764 			break;
765 
766 		case JWINSIZE:
767 		case TIOCGWINSZ:
768 		case TIOCSWINSZ:
769 			ptioc(q, mp, WRSIDE);
770 			break;
771 
772 		case TIOCSTI:
773 			/*
774 			 * Simulate typing of a character at the terminal.  In
775 			 * all cases, we acknowledge the ioctl and pass a copy
776 			 * of it along for the PCKT module to encapsulate.  If
777 			 * not in remote mode, we also process the ioctl
778 			 * itself, looping the character given as its argument
779 			 * back around to the read side.
780 			 */
781 
782 			/*
783 			 * Need a copy of this message to pass on to the PCKT
784 			 * module.
785 			 */
786 			if ((pckt_msgp = copymsg(mp)) == NULL) {
787 				miocnak(q, mp, 0, EAGAIN);
788 				break;
789 			}
790 			if ((ntp->state & REMOTEMODE) == 0) {
791 				mblk_t *bp;
792 
793 				error = miocpullup(mp, sizeof (char));
794 				if (error != 0) {
795 					freemsg(pckt_msgp);
796 					miocnak(q, mp, 0, error);
797 					break;
798 				}
799 
800 				/*
801 				 * The permission checking has already been
802 				 * done at the stream head, since it has to be
803 				 * done in the context of the process doing
804 				 * the call.
805 				 */
806 				if ((bp = allocb(1, BPRI_MED)) == NULL) {
807 					freemsg(pckt_msgp);
808 					miocnak(q, mp, 0, EAGAIN);
809 					break;
810 				}
811 				/*
812 				 * XXX:	Is EAGAIN really the right response to
813 				 *	flow control blockage?
814 				 */
815 				if (!bcanputnext(RD(q), mp->b_band)) {
816 					freemsg(bp);
817 					freemsg(pckt_msgp);
818 					miocnak(q, mp, 0, EAGAIN);
819 					break;
820 				}
821 				*bp->b_wptr++ = *mp->b_cont->b_rptr;
822 				qreply(q, bp);
823 			}
824 
825 			putnext(q, pckt_msgp);
826 			mioc2ack(mp, NULL, 0, 0);
827 			qreply(q, mp);
828 			break;
829 
830 		case PTSSTTY:
831 			if (ntp->state & IS_PTSTTY) {
832 				miocnak(q, mp, 0, EEXIST);
833 			} else {
834 				ntp->state |= IS_PTSTTY;
835 				mioc2ack(mp, NULL, 0, 0);
836 				qreply(q, mp);
837 			}
838 			break;
839 
840 		default:
841 			/*
842 			 * End of the line.  The slave driver doesn't see any
843 			 * ioctls that we don't explicitly pass along to it.
844 			 */
845 			miocnak(q, mp, 0, EINVAL);
846 			break;
847 		}
848 		break;
849 
850 	case M_DELAY: /* tty delays not supported */
851 		freemsg(mp);
852 		break;
853 
854 	case M_DATA:
855 		if ((mp->b_wptr - mp->b_rptr) < 0) {
856 			/*
857 			 * Free all bad length messages.
858 			 */
859 			freemsg(mp);
860 			break;
861 		} else if ((mp->b_wptr - mp->b_rptr) == 0) {
862 			if (!(ntp->state & IS_PTSTTY)) {
863 				freemsg(mp);
864 				break;
865 			}
866 		}
867 		if (ntp->state & OFLOW_CTL)
868 			return (0);
869 
870 	default:
871 		putnext(q, mp);
872 		break;
873 
874 	}
875 
876 	return (1);
877 }
878 
879 /*
880  * Message must be of type M_IOCTL or M_IOCDATA for this routine to be called.
881  */
882 static void
883 ptioc(queue_t *q, mblk_t *mp, int qside)
884 {
885 	struct ptem *tp;
886 	struct iocblk *iocp;
887 	struct winsize *wb;
888 	struct jwinsize *jwb;
889 	mblk_t *tmp;
890 	mblk_t *pckt_msgp;	/* message sent to the PCKT module */
891 	int error;
892 
893 	iocp = (struct iocblk *)mp->b_rptr;
894 	tp = (struct ptem *)q->q_ptr;
895 
896 	switch (iocp->ioc_cmd) {
897 
898 	case JWINSIZE:
899 		/*
900 		 * For compatibility:  If all zeros, NAK the message for dumb
901 		 * terminals.
902 		 */
903 		if ((tp->wsz.ws_row == 0) && (tp->wsz.ws_col == 0) &&
904 		    (tp->wsz.ws_xpixel == 0) && (tp->wsz.ws_ypixel == 0)) {
905 			miocnak(q, mp, 0, EINVAL);
906 			return;
907 		}
908 
909 		tmp = allocb(sizeof (struct jwinsize), BPRI_MED);
910 		if (tmp == NULL) {
911 			miocnak(q, mp, 0, EAGAIN);
912 			return;
913 		}
914 
915 		if (iocp->ioc_count == TRANSPARENT)
916 			mcopyout(mp, NULL, sizeof (struct jwinsize), NULL, tmp);
917 		else
918 			mioc2ack(mp, tmp, sizeof (struct jwinsize), 0);
919 
920 		jwb = (struct jwinsize *)mp->b_cont->b_rptr;
921 		jwb->bytesx = tp->wsz.ws_col;
922 		jwb->bytesy = tp->wsz.ws_row;
923 		jwb->bitsx = tp->wsz.ws_xpixel;
924 		jwb->bitsy = tp->wsz.ws_ypixel;
925 
926 		qreply(q, mp);
927 		return;
928 
929 	case TIOCGWINSZ:
930 		/*
931 		 * If all zeros NAK the message for dumb terminals.
932 		 */
933 		if ((tp->wsz.ws_row == 0) && (tp->wsz.ws_col == 0) &&
934 		    (tp->wsz.ws_xpixel == 0) && (tp->wsz.ws_ypixel == 0)) {
935 			miocnak(q, mp, 0, EINVAL);
936 			return;
937 		}
938 
939 		tmp = allocb(sizeof (struct winsize), BPRI_MED);
940 		if (tmp == NULL) {
941 			miocnak(q, mp, 0, EAGAIN);
942 			return;
943 		}
944 
945 		mioc2ack(mp, tmp, sizeof (struct winsize), 0);
946 
947 		wb = (struct winsize *)mp->b_cont->b_rptr;
948 		wb->ws_row = tp->wsz.ws_row;
949 		wb->ws_col = tp->wsz.ws_col;
950 		wb->ws_xpixel = tp->wsz.ws_xpixel;
951 		wb->ws_ypixel = tp->wsz.ws_ypixel;
952 
953 		qreply(q, mp);
954 		return;
955 
956 	case TIOCSWINSZ:
957 		error = miocpullup(mp, sizeof (struct winsize));
958 		if (error != 0) {
959 			miocnak(q, mp, 0, error);
960 			return;
961 		}
962 
963 		wb = (struct winsize *)mp->b_cont->b_rptr;
964 		/*
965 		 * Send a SIGWINCH signal if the row/col information has
966 		 * changed.
967 		 */
968 		if ((tp->wsz.ws_row != wb->ws_row) ||
969 		    (tp->wsz.ws_col != wb->ws_col) ||
970 		    (tp->wsz.ws_xpixel != wb->ws_xpixel) ||
971 		    (tp->wsz.ws_ypixel != wb->ws_xpixel)) {
972 			/*
973 			 * SIGWINCH is always sent upstream.
974 			 */
975 			if (qside == WRSIDE)
976 				(void) putnextctl1(RD(q), M_SIG, SIGWINCH);
977 			else if (qside == RDSIDE)
978 				(void) putnextctl1(q, M_SIG, SIGWINCH);
979 			/*
980 			 * Message may have come in as an M_IOCDATA; pass it
981 			 * to the master side as an M_IOCTL.
982 			 */
983 			mp->b_datap->db_type = M_IOCTL;
984 			if (qside == WRSIDE) {
985 				/*
986 				 * Need a copy of this message to pass on to
987 				 * the PCKT module, only if the M_IOCTL
988 				 * orginated from the slave side.
989 				 */
990 				if ((pckt_msgp = copymsg(mp)) == NULL) {
991 					miocnak(q, mp, 0, EAGAIN);
992 					return;
993 				}
994 				putnext(q, pckt_msgp);
995 			}
996 			tp->wsz.ws_row = wb->ws_row;
997 			tp->wsz.ws_col = wb->ws_col;
998 			tp->wsz.ws_xpixel = wb->ws_xpixel;
999 			tp->wsz.ws_ypixel = wb->ws_ypixel;
1000 		}
1001 
1002 		mioc2ack(mp, NULL, 0, 0);
1003 		qreply(q, mp);
1004 		return;
1005 
1006 	case TIOCSIGNAL: {
1007 		/*
1008 		 * This ioctl can emanate from the master side in remote
1009 		 * mode only.
1010 		 */
1011 		int	sig;
1012 
1013 		if (DB_TYPE(mp) == M_IOCTL && iocp->ioc_count != TRANSPARENT) {
1014 			error = miocpullup(mp, sizeof (int));
1015 			if (error != 0) {
1016 				miocnak(q, mp, 0, error);
1017 				return;
1018 			}
1019 		}
1020 
1021 		if (DB_TYPE(mp) == M_IOCDATA || iocp->ioc_count != TRANSPARENT)
1022 			sig = *(int *)mp->b_cont->b_rptr;
1023 		else
1024 			sig = (int)*(intptr_t *)mp->b_cont->b_rptr;
1025 
1026 		if (sig < 1 || sig >= NSIG) {
1027 			miocnak(q, mp, 0, EINVAL);
1028 			return;
1029 		}
1030 
1031 		/*
1032 		 * Send an M_PCSIG message up the slave's read side and
1033 		 * respond back to the master with an ACK or NAK as
1034 		 * appropriate.
1035 		 */
1036 		if (putnextctl1(q, M_PCSIG, sig) == 0) {
1037 			miocnak(q, mp, 0, EAGAIN);
1038 			return;
1039 		}
1040 
1041 		mioc2ack(mp, NULL, 0, 0);
1042 		qreply(q, mp);
1043 		return;
1044 	    }
1045 
1046 	case TIOCREMOTE: {
1047 		int	onoff;
1048 		mblk_t	*mctlp;
1049 
1050 		if (DB_TYPE(mp) == M_IOCTL) {
1051 			error = miocpullup(mp, sizeof (int));
1052 			if (error != 0) {
1053 				miocnak(q, mp, 0, error);
1054 				return;
1055 			}
1056 		}
1057 
1058 		onoff = *(int *)mp->b_cont->b_rptr;
1059 
1060 		/*
1061 		 * Send M_CTL up using the iocblk format.
1062 		 */
1063 		mctlp = mkiocb(onoff ? MC_NO_CANON : MC_DO_CANON);
1064 		if (mctlp == NULL) {
1065 			miocnak(q, mp, 0, EAGAIN);
1066 			return;
1067 		}
1068 		mctlp->b_datap->db_type = M_CTL;
1069 		putnext(q, mctlp);
1070 
1071 		/*
1072 		 * ACK the ioctl.
1073 		 */
1074 		mioc2ack(mp, NULL, 0, 0);
1075 		qreply(q, mp);
1076 
1077 		/*
1078 		 * Record state change.
1079 		 */
1080 		if (onoff)
1081 			tp->state |= REMOTEMODE;
1082 		else
1083 			tp->state &= ~REMOTEMODE;
1084 		return;
1085 	    }
1086 
1087 	default:
1088 		putnext(q, mp);
1089 		return;
1090 	}
1091 }
1092