1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2008 Ed Schouten <ed@FreeBSD.org>
5 * All rights reserved.
6 *
7 * Portions of this software were developed under sponsorship from Snow
8 * B.V., the Netherlands.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD: stable/12/sys/kern/tty_pts.c 356020 2019-12-22 19:06:45Z kevans $");
34
35 /* Add compatibility bits for FreeBSD. */
36 #define PTS_COMPAT
37 /* Add pty(4) compat bits. */
38 #define PTS_EXTERNAL
39 /* Add bits to make Linux binaries work. */
40 #define PTS_LINUX
41
42 #include <sys/param.h>
43 #include <sys/lock.h>
44 #include <sys/condvar.h>
45 #include <sys/conf.h>
46 #include <sys/fcntl.h>
47 #include <sys/file.h>
48 #include <sys/filedesc.h>
49 #include <sys/filio.h>
50 #include <sys/kernel.h>
51 #include <sys/limits.h>
52 #include <sys/malloc.h>
53 #include <sys/mutex.h>
54 #include <sys/poll.h>
55 #include <sys/proc.h>
56 #include <sys/racct.h>
57 #include <sys/resourcevar.h>
58 #include <sys/serial.h>
59 #include <sys/stat.h>
60 #include <sys/syscall.h>
61 #include <sys/syscallsubr.h>
62 #include <sys/sysctl.h>
63 #include <sys/sysent.h>
64 #include <sys/sysproto.h>
65 #include <sys/systm.h>
66 #include <sys/tty.h>
67 #include <sys/ttycom.h>
68 #include <sys/uio.h>
69 #include <sys/user.h>
70
71 #include <machine/stdarg.h>
72
73 /*
74 * Our utmp(5) format is limited to 8-byte TTY line names. This means
75 * we can at most allocate 1000 pseudo-terminals ("pts/999"). Allow
76 * users to increase this number, assuming they have manually increased
77 * UT_LINESIZE.
78 */
79 static struct unrhdr *pts_pool;
80
81 static MALLOC_DEFINE(M_PTS, "pts", "pseudo tty device");
82
83 /*
84 * Per-PTS structure.
85 *
86 * List of locks
87 * (t) locked by tty_lock()
88 * (c) const until freeing
89 */
90 struct pts_softc {
91 int pts_unit; /* (c) Device unit number. */
92 unsigned int pts_flags; /* (t) Device flags. */
93 #define PTS_PKT 0x1 /* Packet mode. */
94 #define PTS_FINISHED 0x2 /* Return errors on read()/write(). */
95 char pts_pkt; /* (t) Unread packet mode data. */
96
97 struct cv pts_inwait; /* (t) Blocking write() on master. */
98 struct selinfo pts_inpoll; /* (t) Select queue for write(). */
99 struct cv pts_outwait; /* (t) Blocking read() on master. */
100 struct selinfo pts_outpoll; /* (t) Select queue for read(). */
101
102 #ifdef PTS_EXTERNAL
103 struct cdev *pts_cdev; /* (c) Master device node. */
104 #endif /* PTS_EXTERNAL */
105
106 struct ucred *pts_cred; /* (c) Resource limit. */
107 };
108
109 /*
110 * Controller-side file operations.
111 */
112
113 static int
ptsdev_read(struct file * fp,struct uio * uio,struct ucred * active_cred,int flags,struct thread * td)114 ptsdev_read(struct file *fp, struct uio *uio, struct ucred *active_cred,
115 int flags, struct thread *td)
116 {
117 struct tty *tp = fp->f_data;
118 struct pts_softc *psc = tty_softc(tp);
119 int error = 0;
120 char pkt;
121
122 if (uio->uio_resid == 0)
123 return (0);
124
125 tty_lock(tp);
126
127 for (;;) {
128 /*
129 * Implement packet mode. When packet mode is turned on,
130 * the first byte contains a bitmask of events that
131 * occurred (start, stop, flush, window size, etc).
132 */
133 if (psc->pts_flags & PTS_PKT && psc->pts_pkt) {
134 pkt = psc->pts_pkt;
135 psc->pts_pkt = 0;
136 tty_unlock(tp);
137
138 error = ureadc(pkt, uio);
139 return (error);
140 }
141
142 /*
143 * Transmit regular data.
144 *
145 * XXX: We shouldn't use ttydisc_getc_poll()! Even
146 * though in this implementation, there is likely going
147 * to be data, we should just call ttydisc_getc_uio()
148 * and use its return value to sleep.
149 */
150 if (ttydisc_getc_poll(tp)) {
151 if (psc->pts_flags & PTS_PKT) {
152 /*
153 * XXX: Small race. Fortunately PTY
154 * consumers aren't multithreaded.
155 */
156
157 tty_unlock(tp);
158 error = ureadc(TIOCPKT_DATA, uio);
159 if (error)
160 return (error);
161 tty_lock(tp);
162 }
163
164 error = ttydisc_getc_uio(tp, uio);
165 break;
166 }
167
168 /* Maybe the device isn't used anyway. */
169 if (psc->pts_flags & PTS_FINISHED)
170 break;
171
172 /* Wait for more data. */
173 if (fp->f_flag & O_NONBLOCK) {
174 error = EWOULDBLOCK;
175 break;
176 }
177 error = cv_wait_sig(&psc->pts_outwait, tp->t_mtx);
178 if (error != 0)
179 break;
180 }
181
182 tty_unlock(tp);
183
184 return (error);
185 }
186
187 static int
ptsdev_write(struct file * fp,struct uio * uio,struct ucred * active_cred,int flags,struct thread * td)188 ptsdev_write(struct file *fp, struct uio *uio, struct ucred *active_cred,
189 int flags, struct thread *td)
190 {
191 struct tty *tp = fp->f_data;
192 struct pts_softc *psc = tty_softc(tp);
193 char ib[256], *ibstart;
194 size_t iblen, rintlen;
195 int error = 0;
196
197 if (uio->uio_resid == 0)
198 return (0);
199
200 for (;;) {
201 ibstart = ib;
202 iblen = MIN(uio->uio_resid, sizeof ib);
203 error = uiomove(ib, iblen, uio);
204
205 tty_lock(tp);
206 if (error != 0) {
207 iblen = 0;
208 goto done;
209 }
210
211 /*
212 * When possible, avoid the slow path. rint_bypass()
213 * copies all input to the input queue at once.
214 */
215 MPASS(iblen > 0);
216 do {
217 rintlen = ttydisc_rint_simple(tp, ibstart, iblen);
218 ibstart += rintlen;
219 iblen -= rintlen;
220 if (iblen == 0) {
221 /* All data written. */
222 break;
223 }
224
225 /* Maybe the device isn't used anyway. */
226 if (psc->pts_flags & PTS_FINISHED) {
227 error = EIO;
228 goto done;
229 }
230
231 /* Wait for more data. */
232 if (fp->f_flag & O_NONBLOCK) {
233 error = EWOULDBLOCK;
234 goto done;
235 }
236
237 /* Wake up users on the slave side. */
238 ttydisc_rint_done(tp);
239 error = cv_wait_sig(&psc->pts_inwait, tp->t_mtx);
240 if (error != 0)
241 goto done;
242 } while (iblen > 0);
243
244 if (uio->uio_resid == 0)
245 break;
246 tty_unlock(tp);
247 }
248
249 done: ttydisc_rint_done(tp);
250 tty_unlock(tp);
251
252 /*
253 * Don't account for the part of the buffer that we couldn't
254 * pass to the TTY.
255 */
256 uio->uio_resid += iblen;
257 return (error);
258 }
259
260 static int
ptsdev_ioctl(struct file * fp,u_long cmd,void * data,struct ucred * active_cred,struct thread * td)261 ptsdev_ioctl(struct file *fp, u_long cmd, void *data,
262 struct ucred *active_cred, struct thread *td)
263 {
264 struct tty *tp = fp->f_data;
265 struct pts_softc *psc = tty_softc(tp);
266 int error = 0, sig;
267
268 switch (cmd) {
269 case FIODTYPE:
270 *(int *)data = D_TTY;
271 return (0);
272 case FIONBIO:
273 /* This device supports non-blocking operation. */
274 return (0);
275 case FIONREAD:
276 tty_lock(tp);
277 if (psc->pts_flags & PTS_FINISHED) {
278 /* Force read() to be called. */
279 *(int *)data = 1;
280 } else {
281 *(int *)data = ttydisc_getc_poll(tp);
282 }
283 tty_unlock(tp);
284 return (0);
285 case FIODGNAME: {
286 struct fiodgname_arg *fgn;
287 const char *p;
288 int i;
289
290 /* Reverse device name lookups, for ptsname() and ttyname(). */
291 fgn = data;
292 p = tty_devname(tp);
293 i = strlen(p) + 1;
294 if (i > fgn->len)
295 return (EINVAL);
296 return copyout(p, fgn->buf, i);
297 }
298
299 /*
300 * We need to implement TIOCGPGRP and TIOCGSID here again. When
301 * called on the pseudo-terminal master, it should not check if
302 * the terminal is the foreground terminal of the calling
303 * process.
304 *
305 * TIOCGETA is also implemented here. Various Linux PTY routines
306 * often call isatty(), which is implemented by tcgetattr().
307 */
308 #ifdef PTS_LINUX
309 case TIOCGETA:
310 /* Obtain terminal flags through tcgetattr(). */
311 tty_lock(tp);
312 *(struct termios*)data = tp->t_termios;
313 tty_unlock(tp);
314 return (0);
315 #endif /* PTS_LINUX */
316 case TIOCSETAF:
317 case TIOCSETAW:
318 /*
319 * We must make sure we turn tcsetattr() calls of TCSAFLUSH and
320 * TCSADRAIN into something different. If an application would
321 * call TCSAFLUSH or TCSADRAIN on the master descriptor, it may
322 * deadlock waiting for all data to be read.
323 */
324 cmd = TIOCSETA;
325 break;
326 #if defined(PTS_COMPAT) || defined(PTS_LINUX)
327 case TIOCGPTN:
328 /*
329 * Get the device unit number.
330 */
331 if (psc->pts_unit < 0)
332 return (ENOTTY);
333 *(unsigned int *)data = psc->pts_unit;
334 return (0);
335 #endif /* PTS_COMPAT || PTS_LINUX */
336 case TIOCGPGRP:
337 /* Get the foreground process group ID. */
338 tty_lock(tp);
339 if (tp->t_pgrp != NULL)
340 *(int *)data = tp->t_pgrp->pg_id;
341 else
342 *(int *)data = NO_PID;
343 tty_unlock(tp);
344 return (0);
345 case TIOCGSID:
346 /* Get the session leader process ID. */
347 tty_lock(tp);
348 if (tp->t_session == NULL)
349 error = ENOTTY;
350 else
351 *(int *)data = tp->t_session->s_sid;
352 tty_unlock(tp);
353 return (error);
354 case TIOCPTMASTER:
355 /* Yes, we are a pseudo-terminal master. */
356 return (0);
357 case TIOCSIG:
358 /* Signal the foreground process group. */
359 sig = *(int *)data;
360 if (sig < 1 || sig >= NSIG)
361 return (EINVAL);
362
363 tty_lock(tp);
364 tty_signal_pgrp(tp, sig);
365 tty_unlock(tp);
366 return (0);
367 case TIOCPKT:
368 /* Enable/disable packet mode. */
369 tty_lock(tp);
370 if (*(int *)data)
371 psc->pts_flags |= PTS_PKT;
372 else
373 psc->pts_flags &= ~PTS_PKT;
374 tty_unlock(tp);
375 return (0);
376 }
377
378 /* Just redirect this ioctl to the slave device. */
379 tty_lock(tp);
380 error = tty_ioctl(tp, cmd, data, fp->f_flag, td);
381 tty_unlock(tp);
382 if (error == ENOIOCTL)
383 error = ENOTTY;
384
385 return (error);
386 }
387
388 static int
ptsdev_poll(struct file * fp,int events,struct ucred * active_cred,struct thread * td)389 ptsdev_poll(struct file *fp, int events, struct ucred *active_cred,
390 struct thread *td)
391 {
392 struct tty *tp = fp->f_data;
393 struct pts_softc *psc = tty_softc(tp);
394 int revents = 0;
395
396 tty_lock(tp);
397
398 if (psc->pts_flags & PTS_FINISHED) {
399 /* Slave device is not opened. */
400 tty_unlock(tp);
401 return ((events & (POLLIN|POLLRDNORM)) | POLLHUP);
402 }
403
404 if (events & (POLLIN|POLLRDNORM)) {
405 /* See if we can getc something. */
406 if (ttydisc_getc_poll(tp) ||
407 (psc->pts_flags & PTS_PKT && psc->pts_pkt))
408 revents |= events & (POLLIN|POLLRDNORM);
409 }
410 if (events & (POLLOUT|POLLWRNORM)) {
411 /* See if we can rint something. */
412 if (ttydisc_rint_poll(tp))
413 revents |= events & (POLLOUT|POLLWRNORM);
414 }
415
416 /*
417 * No need to check for POLLHUP here. This device cannot be used
418 * as a callout device, which means we always have a carrier,
419 * because the master is.
420 */
421
422 if (revents == 0) {
423 /*
424 * This code might look misleading, but the naming of
425 * poll events on this side is the opposite of the slave
426 * device.
427 */
428 if (events & (POLLIN|POLLRDNORM))
429 selrecord(td, &psc->pts_outpoll);
430 if (events & (POLLOUT|POLLWRNORM))
431 selrecord(td, &psc->pts_inpoll);
432 }
433
434 tty_unlock(tp);
435
436 return (revents);
437 }
438
439 /*
440 * kqueue support.
441 */
442
443 static void
pts_kqops_read_detach(struct knote * kn)444 pts_kqops_read_detach(struct knote *kn)
445 {
446 struct file *fp = kn->kn_fp;
447 struct tty *tp = fp->f_data;
448 struct pts_softc *psc = tty_softc(tp);
449
450 knlist_remove(&psc->pts_outpoll.si_note, kn, 0);
451 }
452
453 static int
pts_kqops_read_event(struct knote * kn,long hint)454 pts_kqops_read_event(struct knote *kn, long hint)
455 {
456 struct file *fp = kn->kn_fp;
457 struct tty *tp = fp->f_data;
458 struct pts_softc *psc = tty_softc(tp);
459
460 if (psc->pts_flags & PTS_FINISHED) {
461 kn->kn_flags |= EV_EOF;
462 return (1);
463 } else {
464 kn->kn_data = ttydisc_getc_poll(tp);
465 return (kn->kn_data > 0);
466 }
467 }
468
469 static void
pts_kqops_write_detach(struct knote * kn)470 pts_kqops_write_detach(struct knote *kn)
471 {
472 struct file *fp = kn->kn_fp;
473 struct tty *tp = fp->f_data;
474 struct pts_softc *psc = tty_softc(tp);
475
476 knlist_remove(&psc->pts_inpoll.si_note, kn, 0);
477 }
478
479 static int
pts_kqops_write_event(struct knote * kn,long hint)480 pts_kqops_write_event(struct knote *kn, long hint)
481 {
482 struct file *fp = kn->kn_fp;
483 struct tty *tp = fp->f_data;
484 struct pts_softc *psc = tty_softc(tp);
485
486 if (psc->pts_flags & PTS_FINISHED) {
487 kn->kn_flags |= EV_EOF;
488 return (1);
489 } else {
490 kn->kn_data = ttydisc_rint_poll(tp);
491 return (kn->kn_data > 0);
492 }
493 }
494
495 static struct filterops pts_kqops_read = {
496 .f_isfd = 1,
497 .f_detach = pts_kqops_read_detach,
498 .f_event = pts_kqops_read_event,
499 };
500 static struct filterops pts_kqops_write = {
501 .f_isfd = 1,
502 .f_detach = pts_kqops_write_detach,
503 .f_event = pts_kqops_write_event,
504 };
505
506 static int
ptsdev_kqfilter(struct file * fp,struct knote * kn)507 ptsdev_kqfilter(struct file *fp, struct knote *kn)
508 {
509 struct tty *tp = fp->f_data;
510 struct pts_softc *psc = tty_softc(tp);
511 int error = 0;
512
513 tty_lock(tp);
514
515 switch (kn->kn_filter) {
516 case EVFILT_READ:
517 kn->kn_fop = &pts_kqops_read;
518 knlist_add(&psc->pts_outpoll.si_note, kn, 1);
519 break;
520 case EVFILT_WRITE:
521 kn->kn_fop = &pts_kqops_write;
522 knlist_add(&psc->pts_inpoll.si_note, kn, 1);
523 break;
524 default:
525 error = EINVAL;
526 break;
527 }
528
529 tty_unlock(tp);
530 return (error);
531 }
532
533 static int
ptsdev_stat(struct file * fp,struct stat * sb,struct ucred * active_cred,struct thread * td)534 ptsdev_stat(struct file *fp, struct stat *sb, struct ucred *active_cred,
535 struct thread *td)
536 {
537 struct tty *tp = fp->f_data;
538 #ifdef PTS_EXTERNAL
539 struct pts_softc *psc = tty_softc(tp);
540 #endif /* PTS_EXTERNAL */
541 struct cdev *dev = tp->t_dev;
542
543 /*
544 * According to POSIX, we must implement an fstat(). This also
545 * makes this implementation compatible with Linux binaries,
546 * because Linux calls fstat() on the pseudo-terminal master to
547 * obtain st_rdev.
548 *
549 * XXX: POSIX also mentions we must fill in st_dev, but how?
550 */
551
552 bzero(sb, sizeof *sb);
553 #ifdef PTS_EXTERNAL
554 if (psc->pts_cdev != NULL)
555 sb->st_ino = sb->st_rdev = dev2udev(psc->pts_cdev);
556 else
557 #endif /* PTS_EXTERNAL */
558 sb->st_ino = sb->st_rdev = tty_udev(tp);
559
560 sb->st_atim = dev->si_atime;
561 sb->st_ctim = dev->si_ctime;
562 sb->st_mtim = dev->si_mtime;
563 sb->st_uid = dev->si_uid;
564 sb->st_gid = dev->si_gid;
565 sb->st_mode = dev->si_mode | S_IFCHR;
566
567 return (0);
568 }
569
570 static int
ptsdev_close(struct file * fp,struct thread * td)571 ptsdev_close(struct file *fp, struct thread *td)
572 {
573 struct tty *tp = fp->f_data;
574
575 /* Deallocate TTY device. */
576 tty_lock(tp);
577 tty_rel_gone(tp);
578
579 /*
580 * Open of /dev/ptmx or /dev/ptyXX changes the type of file
581 * from DTYPE_VNODE to DTYPE_PTS. vn_open() increases vnode
582 * use count, we need to decrement it, and possibly do other
583 * required cleanup.
584 */
585 if (fp->f_vnode != NULL)
586 return (vnops.fo_close(fp, td));
587
588 return (0);
589 }
590
591 static int
ptsdev_fill_kinfo(struct file * fp,struct kinfo_file * kif,struct filedesc * fdp)592 ptsdev_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp)
593 {
594 struct tty *tp;
595
596 kif->kf_type = KF_TYPE_PTS;
597 tp = fp->f_data;
598 kif->kf_un.kf_pts.kf_pts_dev = tty_udev(tp);
599 kif->kf_un.kf_pts.kf_pts_dev_freebsd11 =
600 kif->kf_un.kf_pts.kf_pts_dev; /* truncate */
601 strlcpy(kif->kf_path, tty_devname(tp), sizeof(kif->kf_path));
602 return (0);
603 }
604
605 static struct fileops ptsdev_ops = {
606 .fo_read = ptsdev_read,
607 .fo_write = ptsdev_write,
608 .fo_truncate = invfo_truncate,
609 .fo_ioctl = ptsdev_ioctl,
610 .fo_poll = ptsdev_poll,
611 .fo_kqfilter = ptsdev_kqfilter,
612 .fo_stat = ptsdev_stat,
613 .fo_close = ptsdev_close,
614 .fo_chmod = invfo_chmod,
615 .fo_chown = invfo_chown,
616 .fo_sendfile = invfo_sendfile,
617 .fo_fill_kinfo = ptsdev_fill_kinfo,
618 .fo_flags = DFLAG_PASSABLE,
619 };
620
621 /*
622 * Driver-side hooks.
623 */
624
625 static void
ptsdrv_outwakeup(struct tty * tp)626 ptsdrv_outwakeup(struct tty *tp)
627 {
628 struct pts_softc *psc = tty_softc(tp);
629
630 cv_broadcast(&psc->pts_outwait);
631 selwakeup(&psc->pts_outpoll);
632 KNOTE_LOCKED(&psc->pts_outpoll.si_note, 0);
633 }
634
635 static void
ptsdrv_inwakeup(struct tty * tp)636 ptsdrv_inwakeup(struct tty *tp)
637 {
638 struct pts_softc *psc = tty_softc(tp);
639
640 cv_broadcast(&psc->pts_inwait);
641 selwakeup(&psc->pts_inpoll);
642 KNOTE_LOCKED(&psc->pts_inpoll.si_note, 0);
643 }
644
645 static int
ptsdrv_open(struct tty * tp)646 ptsdrv_open(struct tty *tp)
647 {
648 struct pts_softc *psc = tty_softc(tp);
649
650 psc->pts_flags &= ~PTS_FINISHED;
651
652 return (0);
653 }
654
655 static void
ptsdrv_close(struct tty * tp)656 ptsdrv_close(struct tty *tp)
657 {
658 struct pts_softc *psc = tty_softc(tp);
659
660 /* Wake up any blocked readers/writers. */
661 psc->pts_flags |= PTS_FINISHED;
662 ptsdrv_outwakeup(tp);
663 ptsdrv_inwakeup(tp);
664 }
665
666 static void
ptsdrv_pktnotify(struct tty * tp,char event)667 ptsdrv_pktnotify(struct tty *tp, char event)
668 {
669 struct pts_softc *psc = tty_softc(tp);
670
671 /*
672 * Clear conflicting flags.
673 */
674
675 switch (event) {
676 case TIOCPKT_STOP:
677 psc->pts_pkt &= ~TIOCPKT_START;
678 break;
679 case TIOCPKT_START:
680 psc->pts_pkt &= ~TIOCPKT_STOP;
681 break;
682 case TIOCPKT_NOSTOP:
683 psc->pts_pkt &= ~TIOCPKT_DOSTOP;
684 break;
685 case TIOCPKT_DOSTOP:
686 psc->pts_pkt &= ~TIOCPKT_NOSTOP;
687 break;
688 }
689
690 psc->pts_pkt |= event;
691 ptsdrv_outwakeup(tp);
692 }
693
694 static void
ptsdrv_free(void * softc)695 ptsdrv_free(void *softc)
696 {
697 struct pts_softc *psc = softc;
698
699 /* Make device number available again. */
700 if (psc->pts_unit >= 0)
701 free_unr(pts_pool, psc->pts_unit);
702
703 chgptscnt(psc->pts_cred->cr_ruidinfo, -1, 0);
704 racct_sub_cred(psc->pts_cred, RACCT_NPTS, 1);
705 crfree(psc->pts_cred);
706
707 seldrain(&psc->pts_inpoll);
708 seldrain(&psc->pts_outpoll);
709 knlist_destroy(&psc->pts_inpoll.si_note);
710 knlist_destroy(&psc->pts_outpoll.si_note);
711
712 #ifdef PTS_EXTERNAL
713 /* Destroy master device as well. */
714 if (psc->pts_cdev != NULL)
715 destroy_dev_sched(psc->pts_cdev);
716 #endif /* PTS_EXTERNAL */
717
718 free(psc, M_PTS);
719 }
720
721 static struct ttydevsw pts_class = {
722 .tsw_flags = TF_NOPREFIX,
723 .tsw_outwakeup = ptsdrv_outwakeup,
724 .tsw_inwakeup = ptsdrv_inwakeup,
725 .tsw_open = ptsdrv_open,
726 .tsw_close = ptsdrv_close,
727 .tsw_pktnotify = ptsdrv_pktnotify,
728 .tsw_free = ptsdrv_free,
729 };
730
731 #ifndef PTS_EXTERNAL
732 static
733 #endif /* !PTS_EXTERNAL */
734 int
pts_alloc(int fflags,struct thread * td,struct file * fp)735 pts_alloc(int fflags, struct thread *td, struct file *fp)
736 {
737 int unit, ok, error;
738 struct tty *tp;
739 struct pts_softc *psc;
740 struct proc *p = td->td_proc;
741 struct ucred *cred = td->td_ucred;
742
743 /* Resource limiting. */
744 PROC_LOCK(p);
745 error = racct_add(p, RACCT_NPTS, 1);
746 if (error != 0) {
747 PROC_UNLOCK(p);
748 return (EAGAIN);
749 }
750 ok = chgptscnt(cred->cr_ruidinfo, 1, lim_cur(td, RLIMIT_NPTS));
751 if (!ok) {
752 racct_sub(p, RACCT_NPTS, 1);
753 PROC_UNLOCK(p);
754 return (EAGAIN);
755 }
756 PROC_UNLOCK(p);
757
758 /* Try to allocate a new pts unit number. */
759 unit = alloc_unr(pts_pool);
760 if (unit < 0) {
761 racct_sub(p, RACCT_NPTS, 1);
762 chgptscnt(cred->cr_ruidinfo, -1, 0);
763 return (EAGAIN);
764 }
765
766 /* Allocate TTY and softc. */
767 psc = malloc(sizeof(struct pts_softc), M_PTS, M_WAITOK|M_ZERO);
768 cv_init(&psc->pts_inwait, "ptsin");
769 cv_init(&psc->pts_outwait, "ptsout");
770
771 psc->pts_unit = unit;
772 psc->pts_cred = crhold(cred);
773
774 tp = tty_alloc(&pts_class, psc);
775 knlist_init_mtx(&psc->pts_inpoll.si_note, tp->t_mtx);
776 knlist_init_mtx(&psc->pts_outpoll.si_note, tp->t_mtx);
777
778 /* Expose the slave device as well. */
779 tty_makedev(tp, td->td_ucred, "pts/%u", psc->pts_unit);
780
781 finit(fp, fflags, DTYPE_PTS, tp, &ptsdev_ops);
782
783 return (0);
784 }
785
786 #ifdef PTS_EXTERNAL
787 int
pts_alloc_external(int fflags,struct thread * td,struct file * fp,struct cdev * dev,const char * name)788 pts_alloc_external(int fflags, struct thread *td, struct file *fp,
789 struct cdev *dev, const char *name)
790 {
791 int ok, error;
792 struct tty *tp;
793 struct pts_softc *psc;
794 struct proc *p = td->td_proc;
795 struct ucred *cred = td->td_ucred;
796
797 /* Resource limiting. */
798 PROC_LOCK(p);
799 error = racct_add(p, RACCT_NPTS, 1);
800 if (error != 0) {
801 PROC_UNLOCK(p);
802 return (EAGAIN);
803 }
804 ok = chgptscnt(cred->cr_ruidinfo, 1, lim_cur(td, RLIMIT_NPTS));
805 if (!ok) {
806 racct_sub(p, RACCT_NPTS, 1);
807 PROC_UNLOCK(p);
808 return (EAGAIN);
809 }
810 PROC_UNLOCK(p);
811
812 /* Allocate TTY and softc. */
813 psc = malloc(sizeof(struct pts_softc), M_PTS, M_WAITOK|M_ZERO);
814 cv_init(&psc->pts_inwait, "ptsin");
815 cv_init(&psc->pts_outwait, "ptsout");
816
817 psc->pts_unit = -1;
818 psc->pts_cdev = dev;
819 psc->pts_cred = crhold(cred);
820
821 tp = tty_alloc(&pts_class, psc);
822 knlist_init_mtx(&psc->pts_inpoll.si_note, tp->t_mtx);
823 knlist_init_mtx(&psc->pts_outpoll.si_note, tp->t_mtx);
824
825 /* Expose the slave device as well. */
826 tty_makedev(tp, td->td_ucred, "%s", name);
827
828 finit(fp, fflags, DTYPE_PTS, tp, &ptsdev_ops);
829
830 return (0);
831 }
832 #endif /* PTS_EXTERNAL */
833
834 int
sys_posix_openpt(struct thread * td,struct posix_openpt_args * uap)835 sys_posix_openpt(struct thread *td, struct posix_openpt_args *uap)
836 {
837 int error, fd;
838 struct file *fp;
839
840 /*
841 * POSIX states it's unspecified when other flags are passed. We
842 * don't allow this.
843 */
844 if (uap->flags & ~(O_RDWR|O_NOCTTY|O_CLOEXEC))
845 return (EINVAL);
846
847 error = falloc(td, &fp, &fd, uap->flags);
848 if (error)
849 return (error);
850
851 /* Allocate the actual pseudo-TTY. */
852 error = pts_alloc(FFLAGS(uap->flags & O_ACCMODE), td, fp);
853 if (error != 0) {
854 fdclose(td, fp, fd);
855 fdrop(fp, td);
856 return (error);
857 }
858
859 /* Pass it back to userspace. */
860 td->td_retval[0] = fd;
861 fdrop(fp, td);
862
863 return (0);
864 }
865
866 static void
pts_init(void * unused)867 pts_init(void *unused)
868 {
869
870 pts_pool = new_unrhdr(0, INT_MAX, NULL);
871 }
872
873 SYSINIT(pts, SI_SUB_DRIVERS, SI_ORDER_MIDDLE, pts_init, NULL);
874