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 (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21 /*
22 * Copyright (c) 1988, 2010, Oracle and/or its affiliates. All rights reserved.
23 */
24 /* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
25 /* All Rights Reserved */
26
27
28
29 /*
30 * Pseudo Terminal Master Driver.
31 *
32 * The pseudo-tty subsystem simulates a terminal connection, where the master
33 * side represents the terminal and the slave represents the user process's
34 * special device end point. The master device is set up as a cloned device
35 * where its major device number is the major for the clone device and its minor
36 * device number is the major for the ptm driver. There are no nodes in the file
37 * system for master devices. The master pseudo driver is opened using the
38 * open(2) system call with /dev/ptmx as the device parameter. The clone open
39 * finds the next available minor device for the ptm major device.
40 *
41 * A master device is available only if it and its corresponding slave device
42 * are not already open. When the master device is opened, the corresponding
43 * slave device is automatically locked out. Only one open is allowed on a
44 * master device. Multiple opens are allowed on the slave device. After both
45 * the master and slave have been opened, the user has two file descriptors
46 * which are the end points of a full duplex connection composed of two streams
47 * which are automatically connected at the master and slave drivers. The user
48 * may then push modules onto either side of the stream pair.
49 *
50 * The master and slave drivers pass all messages to their adjacent queues.
51 * Only the M_FLUSH needs some processing. Because the read queue of one side
52 * is connected to the write queue of the other, the FLUSHR flag is changed to
53 * the FLUSHW flag and vice versa. When the master device is closed an M_HANGUP
54 * message is sent to the slave device which will render the device
55 * unusable. The process on the slave side gets the EIO when attempting to write
56 * on that stream but it will be able to read any data remaining on the stream
57 * head read queue. When all the data has been read, read() returns 0
58 * indicating that the stream can no longer be used. On the last close of the
59 * slave device, a 0-length message is sent to the master device. When the
60 * application on the master side issues a read() or getmsg() and 0 is returned,
61 * the user of the master device decides whether to issue a close() that
62 * dismantles the pseudo-terminal subsystem. If the master device is not closed,
63 * the pseudo-tty subsystem will be available to another user to open the slave
64 * device.
65 *
66 * If O_NONBLOCK or O_NDELAY is set, read on the master side returns -1 with
67 * errno set to EAGAIN if no data is available, and write returns -1 with errno
68 * set to EAGAIN if there is internal flow control.
69 *
70 * IOCTLS:
71 *
72 * ISPTM: determines whether the file descriptor is that of an open master
73 * device. Return code of zero indicates that the file descriptor
74 * represents master device.
75 *
76 * UNLKPT: unlocks the master and slave devices. It returns 0 on success. On
77 * failure, the errno is set to EINVAL indicating that the master
78 * device is not open.
79 *
80 * ZONEPT: sets the zone membership of the associated pts device.
81 *
82 * GRPPT: sets the group owner of the associated pts device.
83 *
84 * Synchronization:
85 *
86 * All global data synchronization between ptm/pts is done via global
87 * ptms_lock mutex which is initialized at system boot time from
88 * ptms_initspace (called from space.c).
89 *
90 * Individual fields of pt_ttys structure (except ptm_rdq, pts_rdq and
91 * pt_nullmsg) are protected by pt_ttys.pt_lock mutex.
92 *
93 * PT_ENTER_READ/PT_ENTER_WRITE are reference counter based read-write locks
94 * which allow reader locks to be reacquired by the same thread (usual
95 * reader/writer locks can't be used for that purpose since it is illegal for
96 * a thread to acquire a lock it already holds, even as a reader). The sole
97 * purpose of these macros is to guarantee that the peer queue will not
98 * disappear (due to closing peer) while it is used. It is safe to use
99 * PT_ENTER_READ/PT_EXIT_READ brackets across calls like putq/putnext (since
100 * they are not real locks but reference counts).
101 *
102 * PT_ENTER_WRITE/PT_EXIT_WRITE brackets are used ONLY in master/slave
103 * open/close paths to modify ptm_rdq and pts_rdq fields. These fields should
104 * be set to appropriate queues *after* qprocson() is called during open (to
105 * prevent peer from accessing the queue with incomplete plumbing) and set to
106 * NULL before qprocsoff() is called during close.
107 *
108 * The pt_nullmsg field is only used in open/close routines and it is also
109 * protected by PT_ENTER_WRITE/PT_EXIT_WRITE brackets to avoid extra mutex
110 * holds.
111 *
112 * Lock Ordering:
113 *
114 * If both ptms_lock and per-pty lock should be held, ptms_lock should always
115 * be entered first, followed by per-pty lock.
116 *
117 * See ptms.h, pts.c and ptms_conf.c for more information.
118 */
119
120 #include <sys/types.h>
121 #include <sys/param.h>
122 #include <sys/file.h>
123 #include <sys/sysmacros.h>
124 #include <sys/stream.h>
125 #include <sys/stropts.h>
126 #include <sys/proc.h>
127 #include <sys/errno.h>
128 #include <sys/debug.h>
129 #include <sys/cmn_err.h>
130 #include <sys/ptms.h>
131 #include <sys/stat.h>
132 #include <sys/strsun.h>
133 #include <sys/systm.h>
134 #include <sys/modctl.h>
135 #include <sys/conf.h>
136 #include <sys/ddi.h>
137 #include <sys/sunddi.h>
138 #include <sys/zone.h>
139
140 #ifdef DEBUG
141 int ptm_debug = 0;
142 #define DBG(a) if (ptm_debug) cmn_err(CE_NOTE, a)
143 #else
144 #define DBG(a)
145 #endif
146
147 static int ptmopen(queue_t *, dev_t *, int, int, cred_t *);
148 static int ptmclose(queue_t *, int, cred_t *);
149 static int ptmwput(queue_t *, mblk_t *);
150 static int ptmrsrv(queue_t *);
151 static int ptmwsrv(queue_t *);
152
153 /*
154 * Master Stream Pseudo Terminal Module: stream data structure definitions
155 */
156
157 static struct module_info ptm_info = {
158 0xdead,
159 "ptm",
160 0,
161 512,
162 512,
163 128
164 };
165
166 static struct qinit ptmrint = {
167 NULL,
168 ptmrsrv,
169 ptmopen,
170 ptmclose,
171 NULL,
172 &ptm_info,
173 NULL
174 };
175
176 static struct qinit ptmwint = {
177 ptmwput,
178 ptmwsrv,
179 NULL,
180 NULL,
181 NULL,
182 &ptm_info,
183 NULL
184 };
185
186 static struct streamtab ptminfo = {
187 &ptmrint,
188 &ptmwint,
189 NULL,
190 NULL
191 };
192
193 static int ptm_attach(dev_info_t *, ddi_attach_cmd_t);
194 static int ptm_detach(dev_info_t *, ddi_detach_cmd_t);
195 static int ptm_devinfo(dev_info_t *, ddi_info_cmd_t, void *, void **);
196
197 static dev_info_t *ptm_dip; /* private devinfo pointer */
198
199 /*
200 * this will define (struct cb_ops cb_ptm_ops) and (struct dev_ops ptm_ops)
201 */
202 DDI_DEFINE_STREAM_OPS(ptm_ops, nulldev, nulldev, ptm_attach, ptm_detach,
203 nodev, ptm_devinfo, D_MP, &ptminfo, ddi_quiesce_not_supported);
204
205 /*
206 * Module linkage information for the kernel.
207 */
208
209 static struct modldrv modldrv = {
210 &mod_driverops, /* Type of module. This one is a pseudo driver */
211 "Master streams driver 'ptm'",
212 &ptm_ops, /* driver ops */
213 };
214
215 static struct modlinkage modlinkage = {
216 MODREV_1,
217 &modldrv,
218 NULL
219 };
220
221 int
222 _init(void)
223 {
224 int rc;
225
226 if ((rc = mod_install(&modlinkage)) == 0)
227 ptms_init();
228 return (rc);
229 }
230
231 int
232 _fini(void)
233 {
234 return (mod_remove(&modlinkage));
235 }
236
237 int
238 _info(struct modinfo *modinfop)
239 {
240 return (mod_info(&modlinkage, modinfop));
241 }
242
243 static int
244 ptm_attach(dev_info_t *devi, ddi_attach_cmd_t cmd)
245 {
246 if (cmd != DDI_ATTACH)
247 return (DDI_FAILURE);
248
249 if (ddi_create_minor_node(devi, "ptmajor", S_IFCHR,
250 0, DDI_PSEUDO, 0) == DDI_FAILURE) {
251 ddi_remove_minor_node(devi, NULL);
252 return (DDI_FAILURE);
253 }
254 if (ddi_create_minor_node(devi, "ptmx", S_IFCHR,
255 0, DDI_PSEUDO, CLONE_DEV) == DDI_FAILURE) {
256 ddi_remove_minor_node(devi, NULL);
257 return (DDI_FAILURE);
258 }
259 ptm_dip = devi;
260
261 return (DDI_SUCCESS);
262 }
263
264 static int
265 ptm_detach(dev_info_t *devi, ddi_detach_cmd_t cmd)
266 {
267 if (cmd != DDI_DETACH)
268 return (DDI_FAILURE);
269
270 ddi_remove_minor_node(devi, NULL);
271 return (DDI_SUCCESS);
272 }
273
274 /*ARGSUSED*/
275 static int
276 ptm_devinfo(dev_info_t *dip, ddi_info_cmd_t infocmd, void *arg,
277 void **result)
278 {
279 int error;
280
281 switch (infocmd) {
282 case DDI_INFO_DEVT2DEVINFO:
283 if (ptm_dip == NULL) {
284 error = DDI_FAILURE;
285 } else {
286 *result = (void *)ptm_dip;
287 error = DDI_SUCCESS;
288 }
289 break;
290 case DDI_INFO_DEVT2INSTANCE:
291 *result = (void *)0;
292 error = DDI_SUCCESS;
293 break;
294 default:
295 error = DDI_FAILURE;
296 }
297 return (error);
298 }
299
300
301 /* ARGSUSED */
302 /*
303 * Open a minor of the master device. Store the write queue pointer and set the
304 * pt_state field to (PTMOPEN | PTLOCK).
305 * This code will work properly with both clone opens and direct opens of the
306 * master device.
307 */
308 static int
309 ptmopen(
310 queue_t *rqp, /* pointer to the read side queue */
311 dev_t *devp, /* pointer to stream tail's dev */
312 int oflag, /* the user open(2) supplied flags */
313 int sflag, /* open state flag */
314 cred_t *credp) /* credentials */
315 {
316 struct pt_ttys *ptmp;
317 mblk_t *mop; /* ptr to a setopts message block */
318 struct stroptions *sop;
319 minor_t dminor = getminor(*devp);
320
321 /* Allow reopen */
322 if (rqp->q_ptr != NULL)
323 return (0);
324
325 if (sflag & MODOPEN)
326 return (ENXIO);
327
328 if (!(sflag & CLONEOPEN) && dminor != 0) {
329 /*
330 * This is a direct open to specific master device through an
331 * artificially created entry with specific minor in
332 * /dev/directory. Such behavior is not supported.
333 */
334 return (ENXIO);
335 }
336
337 /*
338 * The master open requires that the slave be attached
339 * before it returns so that attempts to open the slave will
340 * succeeed
341 */
342 if (ptms_attach_slave() != 0) {
343 return (ENXIO);
344 }
345
346 mop = allocb(sizeof (struct stroptions), BPRI_MED);
347 if (mop == NULL) {
348 DDBG("ptmopen(): mop allocation failed\n", 0);
349 return (ENOMEM);
350 }
351
352 if ((ptmp = pt_ttys_alloc()) == NULL) {
353 DDBG("ptmopen(): pty allocation failed\n", 0);
354 freemsg(mop);
355 return (ENOMEM);
356 }
357
358 dminor = ptmp->pt_minor;
359
360 DDBGP("ptmopen(): allocated ptmp %p\n", (uintptr_t)ptmp);
361 DDBG("ptmopen(): allocated minor %d\n", dminor);
362
363 WR(rqp)->q_ptr = rqp->q_ptr = ptmp;
364
365 qprocson(rqp);
366
367 /* Allow slave to send messages to master */
368 PT_ENTER_WRITE(ptmp);
369 ptmp->ptm_rdq = rqp;
370 PT_EXIT_WRITE(ptmp);
371
372 /*
373 * set up hi/lo water marks on stream head read queue
374 * and add controlling tty if not set
375 */
376 mop->b_datap->db_type = M_SETOPTS;
377 mop->b_wptr += sizeof (struct stroptions);
378 sop = (struct stroptions *)mop->b_rptr;
379 if (oflag & FNOCTTY)
380 sop->so_flags = SO_HIWAT | SO_LOWAT;
381 else
382 sop->so_flags = SO_HIWAT | SO_LOWAT | SO_ISTTY;
383 sop->so_hiwat = _TTY_BUFSIZ;
384 sop->so_lowat = 256;
385 putnext(rqp, mop);
386
387 /*
388 * The input, devp, is a major device number, the output is put
389 * into the same parm as a major,minor pair.
390 */
391 *devp = makedevice(getmajor(*devp), dminor);
392
393 return (0);
394 }
395
396
397 /*
398 * Find the address to private data identifying the slave's write queue.
399 * Send a hang-up message up the slave's read queue to designate the
400 * master/slave pair is tearing down. Uattach the master and slave by
401 * nulling out the write queue fields in the private data structure.
402 * Finally, unlock the master/slave pair and mark the master as closed.
403 */
404 /*ARGSUSED1*/
405 static int
406 ptmclose(queue_t *rqp, int flag, cred_t *credp)
407 {
408 struct pt_ttys *ptmp;
409 queue_t *pts_rdq;
410
411 ASSERT(rqp->q_ptr);
412
413 ptmp = (struct pt_ttys *)rqp->q_ptr;
414 PT_ENTER_READ(ptmp);
415 if (ptmp->pts_rdq) {
416 pts_rdq = ptmp->pts_rdq;
417 if (pts_rdq->q_next) {
418 DBG(("send hangup message to slave\n"));
419 (void) putnextctl(pts_rdq, M_HANGUP);
420 }
421 }
422 PT_EXIT_READ(ptmp);
423 /*
424 * ptm_rdq should be cleared before call to qprocsoff() to prevent pts
425 * write procedure to attempt using ptm_rdq after qprocsoff.
426 */
427 PT_ENTER_WRITE(ptmp);
428 ptmp->ptm_rdq = NULL;
429 freemsg(ptmp->pt_nullmsg);
430 ptmp->pt_nullmsg = NULL;
431 /*
432 * qenable slave side write queue so that it can flush
433 * its messages as master's read queue is going away
434 */
435 if (ptmp->pts_rdq)
436 qenable(WR(ptmp->pts_rdq));
437 PT_EXIT_WRITE(ptmp);
438
439 qprocsoff(rqp);
440
441 /* Finish the close */
442 rqp->q_ptr = NULL;
443 WR(rqp)->q_ptr = NULL;
444
445 ptms_close(ptmp, PTMOPEN | PTLOCK);
446
447 return (0);
448 }
449
450 /*
451 * The wput procedure will only handle ioctl and flush messages.
452 */
453 static int
454 ptmwput(queue_t *qp, mblk_t *mp)
455 {
456 struct pt_ttys *ptmp;
457 struct iocblk *iocp;
458
459 DBG(("entering ptmwput\n"));
460 ASSERT(qp->q_ptr);
461
462 ptmp = (struct pt_ttys *)qp->q_ptr;
463 PT_ENTER_READ(ptmp);
464
465 switch (mp->b_datap->db_type) {
466 /*
467 * if write queue request, flush master's write
468 * queue and send FLUSHR up slave side. If read
469 * queue request, convert to FLUSHW and putnext().
470 */
471 case M_FLUSH:
472 {
473 unsigned char flush_flg = 0;
474
475 DBG(("ptm got flush request\n"));
476 if (*mp->b_rptr & FLUSHW) {
477 DBG(("got FLUSHW, flush ptm write Q\n"));
478 if (*mp->b_rptr & FLUSHBAND)
479 /*
480 * if it is a FLUSHBAND, do flushband.
481 */
482 flushband(qp, *(mp->b_rptr + 1),
483 FLUSHDATA);
484 else
485 flushq(qp, FLUSHDATA);
486 flush_flg = (*mp->b_rptr & ~FLUSHW) | FLUSHR;
487 }
488 if (*mp->b_rptr & FLUSHR) {
489 DBG(("got FLUSHR, set FLUSHW\n"));
490 flush_flg |= (*mp->b_rptr & ~FLUSHR) | FLUSHW;
491 }
492 if (flush_flg != 0 && ptmp->pts_rdq &&
493 !(ptmp->pt_state & PTLOCK)) {
494 DBG(("putnext to pts\n"));
495 *mp->b_rptr = flush_flg;
496 putnext(ptmp->pts_rdq, mp);
497 } else
498 freemsg(mp);
499 break;
500 }
501
502 case M_IOCTL:
503 iocp = (struct iocblk *)mp->b_rptr;
504 switch (iocp->ioc_cmd) {
505 default:
506 if ((ptmp->pt_state & PTLOCK) ||
507 (ptmp->pts_rdq == NULL)) {
508 DBG(("got M_IOCTL but no slave\n"));
509 miocnak(qp, mp, 0, EINVAL);
510 PT_EXIT_READ(ptmp);
511 return (0);
512 }
513 (void) putq(qp, mp);
514 break;
515 case UNLKPT:
516 mutex_enter(&ptmp->pt_lock);
517 ptmp->pt_state &= ~PTLOCK;
518 mutex_exit(&ptmp->pt_lock);
519 /*FALLTHROUGH*/
520 case ISPTM:
521 DBG(("ack the UNLKPT/ISPTM\n"));
522 miocack(qp, mp, 0, 0);
523 break;
524 case ZONEPT:
525 {
526 zoneid_t z;
527 int error;
528
529 if ((error = drv_priv(iocp->ioc_cr)) != 0) {
530 miocnak(qp, mp, 0, error);
531 break;
532 }
533 if ((error = miocpullup(mp, sizeof (zoneid_t))) != 0) {
534 miocnak(qp, mp, 0, error);
535 break;
536 }
537 z = *((zoneid_t *)mp->b_cont->b_rptr);
538 if (z < MIN_ZONEID || z > MAX_ZONEID) {
539 miocnak(qp, mp, 0, EINVAL);
540 break;
541 }
542
543 mutex_enter(&ptmp->pt_lock);
544 ptmp->pt_zoneid = z;
545 mutex_exit(&ptmp->pt_lock);
546 miocack(qp, mp, 0, 0);
547 break;
548 }
549 case OWNERPT:
550 {
551 pt_own_t *ptop;
552 int error;
553 zone_t *zone;
554
555 if ((error = miocpullup(mp, sizeof (pt_own_t))) != 0) {
556 miocnak(qp, mp, 0, error);
557 break;
558 }
559
560 zone = zone_find_by_id(ptmp->pt_zoneid);
561 ptop = (pt_own_t *)mp->b_cont->b_rptr;
562
563 if (!VALID_UID(ptop->pto_ruid, zone) ||
564 !VALID_GID(ptop->pto_rgid, zone)) {
565 zone_rele(zone);
566 miocnak(qp, mp, 0, EINVAL);
567 break;
568 }
569 zone_rele(zone);
570 mutex_enter(&ptmp->pt_lock);
571 ptmp->pt_ruid = ptop->pto_ruid;
572 ptmp->pt_rgid = ptop->pto_rgid;
573 mutex_exit(&ptmp->pt_lock);
574 miocack(qp, mp, 0, 0);
575 break;
576 }
577 }
578 break;
579
580 case M_READ:
581 /* Caused by ldterm - can not pass to slave */
582 freemsg(mp);
583 break;
584
585 /*
586 * send other messages to slave
587 */
588 default:
589 if ((ptmp->pt_state & PTLOCK) || (ptmp->pts_rdq == NULL)) {
590 DBG(("got msg. but no slave\n"));
591 mp = mexchange(NULL, mp, 2, M_ERROR, -1);
592 if (mp != NULL) {
593 mp->b_rptr[0] = NOERROR;
594 mp->b_rptr[1] = EINVAL;
595 qreply(qp, mp);
596 }
597 PT_EXIT_READ(ptmp);
598 return (0);
599 }
600 DBG(("put msg on master's write queue\n"));
601 (void) putq(qp, mp);
602 break;
603 }
604 DBG(("return from ptmwput()\n"));
605 PT_EXIT_READ(ptmp);
606 return (0);
607 }
608
609
610 /*
611 * enable the write side of the slave. This triggers the
612 * slave to send any messages queued on its write side to
613 * the read side of this master.
614 */
615 static int
616 ptmrsrv(queue_t *qp)
617 {
618 struct pt_ttys *ptmp;
619
620 DBG(("entering ptmrsrv\n"));
621 ASSERT(qp->q_ptr);
622
623 ptmp = (struct pt_ttys *)qp->q_ptr;
624 PT_ENTER_READ(ptmp);
625 if (ptmp->pts_rdq) {
626 qenable(WR(ptmp->pts_rdq));
627 }
628 PT_EXIT_READ(ptmp);
629 DBG(("leaving ptmrsrv\n"));
630 return (0);
631 }
632
633
634 /*
635 * If there are messages on this queue that can be sent to
636 * slave, send them via putnext(). Else, if queued messages
637 * cannot be sent, leave them on this queue. If priority
638 * messages on this queue, send them to slave no matter what.
639 */
640 static int
641 ptmwsrv(queue_t *qp)
642 {
643 struct pt_ttys *ptmp;
644 mblk_t *mp;
645
646 DBG(("entering ptmwsrv\n"));
647 ASSERT(qp->q_ptr);
648
649 ptmp = (struct pt_ttys *)qp->q_ptr;
650
651 if ((mp = getq(qp)) == NULL) {
652 /* If there are no messages there's nothing to do. */
653 DBG(("leaving ptmwsrv (no messages)\n"));
654 return (0);
655 }
656
657 PT_ENTER_READ(ptmp);
658 if ((ptmp->pt_state & PTLOCK) || (ptmp->pts_rdq == NULL)) {
659 DBG(("in master write srv proc but no slave\n"));
660 /*
661 * Free messages on the write queue and send
662 * NAK for any M_IOCTL type messages to wakeup
663 * the user process waiting for ACK/NAK from
664 * the ioctl invocation
665 */
666 do {
667 if (mp->b_datap->db_type == M_IOCTL)
668 miocnak(qp, mp, 0, EINVAL);
669 else
670 freemsg(mp);
671 } while ((mp = getq(qp)) != NULL);
672 flushq(qp, FLUSHALL);
673
674 mp = mexchange(NULL, NULL, 2, M_ERROR, -1);
675 if (mp != NULL) {
676 mp->b_rptr[0] = NOERROR;
677 mp->b_rptr[1] = EINVAL;
678 qreply(qp, mp);
679 }
680 PT_EXIT_READ(ptmp);
681 return (0);
682 }
683 /*
684 * while there are messages on this write queue...
685 */
686 do {
687 /*
688 * if don't have control message and cannot put
689 * msg. on slave's read queue, put it back on
690 * this queue.
691 */
692 if (mp->b_datap->db_type <= QPCTL &&
693 !bcanputnext(ptmp->pts_rdq, mp->b_band)) {
694 DBG(("put msg. back on queue\n"));
695 (void) putbq(qp, mp);
696 break;
697 }
698 /*
699 * else send the message up slave's stream
700 */
701 DBG(("send message to slave\n"));
702 putnext(ptmp->pts_rdq, mp);
703 } while ((mp = getq(qp)) != NULL);
704 DBG(("leaving ptmwsrv\n"));
705 PT_EXIT_READ(ptmp);
706 return (0);
707 }