1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
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 /* Add compatibility bits for FreeBSD. */
34 #define PTS_COMPAT
35 /* Add pty(4) compat bits. */
36 #define PTS_EXTERNAL
37 /* Add bits to make Linux binaries work. */
38 #define PTS_LINUX
39
40 #include <sys/param.h>
41 #include <sys/lock.h>
42 #include <sys/condvar.h>
43 #include <sys/conf.h>
44 #include <sys/fcntl.h>
45 #include <sys/file.h>
46 #include <sys/filedesc.h>
47 #include <sys/filio.h>
48 #include <sys/kernel.h>
49 #include <sys/limits.h>
50 #include <sys/malloc.h>
51 #include <sys/mutex.h>
52 #include <sys/poll.h>
53 #include <sys/proc.h>
54 #include <sys/racct.h>
55 #include <sys/resourcevar.h>
56 #include <sys/serial.h>
57 #include <sys/stat.h>
58 #include <sys/stdarg.h>
59 #include <sys/syscall.h>
60 #include <sys/syscallsubr.h>
61 #include <sys/sysctl.h>
62 #include <sys/sysproto.h>
63 #include <sys/systm.h>
64 #include <sys/tty.h>
65 #include <sys/ttycom.h>
66 #include <sys/uio.h>
67 #include <sys/user.h>
68
69 /*
70 * Our utmp(5) format is limited to 8-byte TTY line names. This means
71 * we can at most allocate 1000 pseudo-terminals ("pts/999"). Allow
72 * users to increase this number, assuming they have manually increased
73 * UT_LINESIZE.
74 */
75 static struct unrhdr *pts_pool;
76
77 static MALLOC_DEFINE(M_PTS, "pts", "pseudo tty device");
78
79 /*
80 * Per-PTS structure.
81 *
82 * List of locks
83 * (t) locked by tty_lock()
84 * (c) const until freeing
85 */
86 struct pts_softc {
87 int pts_unit; /* (c) Device unit number. */
88 unsigned int pts_flags; /* (t) Device flags. */
89 #define PTS_PKT 0x1 /* Packet mode. */
90 #define PTS_FINISHED 0x2 /* Return errors on read()/write(). */
91 char pts_pkt; /* (t) Unread packet mode data. */
92
93 struct cv pts_inwait; /* (t) Blocking write() on master. */
94 struct selinfo pts_inpoll; /* (t) Select queue for write(). */
95 struct cv pts_outwait; /* (t) Blocking read() on master. */
96 struct selinfo pts_outpoll; /* (t) Select queue for read(). */
97
98 #ifdef PTS_EXTERNAL
99 struct cdev *pts_cdev; /* (c) Master device node. */
100 #endif /* PTS_EXTERNAL */
101
102 struct ucred *pts_cred; /* (c) Resource limit. */
103 };
104
105 /*
106 * Controller-side file operations.
107 */
108
109 static int
ptsdev_read(struct file * fp,struct uio * uio,struct ucred * active_cred,int flags,struct thread * td)110 ptsdev_read(struct file *fp, struct uio *uio, struct ucred *active_cred,
111 int flags, struct thread *td)
112 {
113 struct tty *tp = fp->f_data;
114 struct pts_softc *psc = tty_softc(tp);
115 int error = 0;
116 char pkt;
117
118 if (uio->uio_resid == 0)
119 return (0);
120
121 tty_lock(tp);
122
123 for (;;) {
124 /*
125 * Implement packet mode. When packet mode is turned on,
126 * the first byte contains a bitmask of events that
127 * occurred (start, stop, flush, window size, etc).
128 */
129 if (psc->pts_flags & PTS_PKT && psc->pts_pkt) {
130 pkt = psc->pts_pkt;
131 psc->pts_pkt = 0;
132 tty_unlock(tp);
133
134 error = ureadc(pkt, uio);
135 return (error);
136 }
137
138 /*
139 * Transmit regular data.
140 *
141 * XXX: We shouldn't use ttydisc_getc_poll()! Even
142 * though in this implementation, there is likely going
143 * to be data, we should just call ttydisc_getc_uio()
144 * and use its return value to sleep.
145 */
146 if (ttydisc_getc_poll(tp)) {
147 if (psc->pts_flags & PTS_PKT) {
148 /*
149 * XXX: Small race. Fortunately PTY
150 * consumers aren't multithreaded.
151 */
152
153 tty_unlock(tp);
154 error = ureadc(TIOCPKT_DATA, uio);
155 if (error)
156 return (error);
157 tty_lock(tp);
158 }
159
160 error = ttydisc_getc_uio(tp, uio);
161 break;
162 }
163
164 /* Maybe the device isn't used anyway. */
165 if (psc->pts_flags & PTS_FINISHED)
166 break;
167
168 /* Wait for more data. */
169 if (fp->f_flag & O_NONBLOCK) {
170 error = EWOULDBLOCK;
171 break;
172 }
173 error = cv_wait_sig(&psc->pts_outwait, tp->t_mtx);
174 if (error != 0)
175 break;
176 }
177
178 tty_unlock(tp);
179
180 return (error);
181 }
182
183 static int
ptsdev_write(struct file * fp,struct uio * uio,struct ucred * active_cred,int flags,struct thread * td)184 ptsdev_write(struct file *fp, struct uio *uio, struct ucred *active_cred,
185 int flags, struct thread *td)
186 {
187 struct tty *tp = fp->f_data;
188 struct pts_softc *psc = tty_softc(tp);
189 char ib[256], *ibstart;
190 size_t iblen, rintlen;
191 int error = 0;
192
193 if (uio->uio_resid == 0)
194 return (0);
195
196 for (;;) {
197 ibstart = ib;
198 iblen = MIN(uio->uio_resid, sizeof ib);
199 error = uiomove(ib, iblen, uio);
200
201 tty_lock(tp);
202 if (error != 0) {
203 iblen = 0;
204 goto done;
205 }
206
207 /*
208 * When possible, avoid the slow path. rint_bypass()
209 * copies all input to the input queue at once.
210 */
211 MPASS(iblen > 0);
212 do {
213 rintlen = ttydisc_rint_simple(tp, ibstart, iblen);
214 ibstart += rintlen;
215 iblen -= rintlen;
216 if (iblen == 0) {
217 /* All data written. */
218 break;
219 }
220
221 /* Maybe the device isn't used anyway. */
222 if (psc->pts_flags & PTS_FINISHED) {
223 error = EIO;
224 goto done;
225 }
226
227 /* Wait for more data. */
228 if (fp->f_flag & O_NONBLOCK) {
229 error = EWOULDBLOCK;
230 goto done;
231 }
232
233 /* Wake up users on the slave side. */
234 ttydisc_rint_done(tp);
235 error = cv_wait_sig(&psc->pts_inwait, tp->t_mtx);
236 if (error != 0)
237 goto done;
238 } while (iblen > 0);
239
240 if (uio->uio_resid == 0)
241 break;
242 tty_unlock(tp);
243 }
244
245 done: ttydisc_rint_done(tp);
246 tty_unlock(tp);
247
248 /*
249 * Don't account for the part of the buffer that we couldn't
250 * pass to the TTY.
251 */
252 uio->uio_resid += iblen;
253 return (error);
254 }
255
256 static int
ptsdev_ioctl(struct file * fp,u_long cmd,void * data,struct ucred * active_cred,struct thread * td)257 ptsdev_ioctl(struct file *fp, u_long cmd, void *data,
258 struct ucred *active_cred, struct thread *td)
259 {
260 struct tty *tp = fp->f_data;
261 struct pts_softc *psc = tty_softc(tp);
262 int error = 0, sig;
263
264 switch (cmd) {
265 case FIODTYPE:
266 *(int *)data = D_TTY;
267 return (0);
268 case FIONBIO:
269 /* This device supports non-blocking operation. */
270 return (0);
271 case FIONREAD:
272 tty_lock(tp);
273 *(int *)data = ttydisc_getc_poll(tp);
274 tty_unlock(tp);
275 return (0);
276 case FIODGNAME:
277 #ifdef COMPAT_FREEBSD32
278 case FIODGNAME_32:
279 #endif
280 {
281 struct fiodgname_arg *fgn;
282 const char *p;
283 int i;
284
285 /* Reverse device name lookups, for ptsname() and ttyname(). */
286 fgn = data;
287 p = tty_devname(tp);
288 i = strlen(p) + 1;
289 if (i > fgn->len)
290 return (EINVAL);
291 return (copyout(p, fiodgname_buf_get_ptr(fgn, cmd), i));
292 }
293
294 /*
295 * We need to implement TIOCGPGRP and TIOCGSID here again. When
296 * called on the pseudo-terminal master, it should not check if
297 * the terminal is the foreground terminal of the calling
298 * process.
299 *
300 * TIOCGETA is also implemented here. Various Linux PTY routines
301 * often call isatty(), which is implemented by tcgetattr().
302 */
303 #ifdef PTS_LINUX
304 case TIOCGETA:
305 /* Obtain terminal flags through tcgetattr(). */
306 tty_lock(tp);
307 *(struct termios*)data = tp->t_termios;
308 tty_unlock(tp);
309 return (0);
310 #endif /* PTS_LINUX */
311 case TIOCSETAF:
312 case TIOCSETAW:
313 /*
314 * We must make sure we turn tcsetattr() calls of TCSAFLUSH and
315 * TCSADRAIN into something different. If an application would
316 * call TCSAFLUSH or TCSADRAIN on the master descriptor, it may
317 * deadlock waiting for all data to be read.
318 */
319 cmd = TIOCSETA;
320 break;
321 #if defined(PTS_COMPAT) || defined(PTS_LINUX)
322 case TIOCGPTN:
323 /*
324 * Get the device unit number.
325 */
326 if (psc->pts_unit < 0)
327 return (ENOTTY);
328 *(unsigned int *)data = psc->pts_unit;
329 return (0);
330 #endif /* PTS_COMPAT || PTS_LINUX */
331 case TIOCGPGRP:
332 /* Get the foreground process group ID. */
333 tty_lock(tp);
334 if (tp->t_pgrp != NULL)
335 *(int *)data = tp->t_pgrp->pg_id;
336 else
337 *(int *)data = NO_PID;
338 tty_unlock(tp);
339 return (0);
340 case TIOCGSID:
341 /* Get the session leader process ID. */
342 tty_lock(tp);
343 if (tp->t_session == NULL)
344 error = ENOTTY;
345 else
346 *(int *)data = tp->t_session->s_sid;
347 tty_unlock(tp);
348 return (error);
349 case TIOCPTMASTER:
350 /* Yes, we are a pseudo-terminal master. */
351 return (0);
352 case TIOCSIG:
353 /* Signal the foreground process group. */
354 sig = *(int *)data;
355 if (sig < 1 || sig >= NSIG)
356 return (EINVAL);
357
358 tty_lock(tp);
359 tty_signal_pgrp(tp, sig);
360 tty_unlock(tp);
361 return (0);
362 case TIOCPKT:
363 /* Enable/disable packet mode. */
364 tty_lock(tp);
365 if (*(int *)data)
366 psc->pts_flags |= PTS_PKT;
367 else
368 psc->pts_flags &= ~PTS_PKT;
369 tty_unlock(tp);
370 return (0);
371 }
372
373 /* Just redirect this ioctl to the slave device. */
374 tty_lock(tp);
375 error = tty_ioctl(tp, cmd, data, fp->f_flag, td);
376 tty_unlock(tp);
377 if (error == ENOIOCTL)
378 error = ENOTTY;
379
380 return (error);
381 }
382
383 static int
ptsdev_poll(struct file * fp,int events,struct ucred * active_cred,struct thread * td)384 ptsdev_poll(struct file *fp, int events, struct ucred *active_cred,
385 struct thread *td)
386 {
387 struct tty *tp = fp->f_data;
388 struct pts_softc *psc = tty_softc(tp);
389 int revents = 0;
390
391 tty_lock(tp);
392
393 if (psc->pts_flags & PTS_FINISHED) {
394 /* Slave device is not opened. */
395 tty_unlock(tp);
396 return ((events & (POLLIN|POLLRDNORM)) | POLLHUP);
397 }
398
399 if (events & (POLLIN|POLLRDNORM)) {
400 /* See if we can getc something. */
401 if (ttydisc_getc_poll(tp) ||
402 (psc->pts_flags & PTS_PKT && psc->pts_pkt))
403 revents |= events & (POLLIN|POLLRDNORM);
404 }
405 if (events & (POLLOUT|POLLWRNORM)) {
406 /* See if we can rint something. */
407 if (ttydisc_rint_poll(tp))
408 revents |= events & (POLLOUT|POLLWRNORM);
409 }
410
411 /*
412 * No need to check for POLLHUP here. This device cannot be used
413 * as a callout device, which means we always have a carrier,
414 * because the master is.
415 */
416
417 if (revents == 0) {
418 /*
419 * This code might look misleading, but the naming of
420 * poll events on this side is the opposite of the slave
421 * device.
422 */
423 if (events & (POLLIN|POLLRDNORM))
424 selrecord(td, &psc->pts_outpoll);
425 if (events & (POLLOUT|POLLWRNORM))
426 selrecord(td, &psc->pts_inpoll);
427 }
428
429 tty_unlock(tp);
430
431 return (revents);
432 }
433
434 /*
435 * kqueue support.
436 */
437
438 static void
pts_kqops_read_detach(struct knote * kn)439 pts_kqops_read_detach(struct knote *kn)
440 {
441 struct file *fp = kn->kn_fp;
442 struct tty *tp = fp->f_data;
443 struct pts_softc *psc = tty_softc(tp);
444
445 knlist_remove(&psc->pts_outpoll.si_note, kn, 0);
446 }
447
448 static int
pts_kqops_read_event(struct knote * kn,long hint)449 pts_kqops_read_event(struct knote *kn, long hint)
450 {
451 struct file *fp = kn->kn_fp;
452 struct tty *tp = fp->f_data;
453 struct pts_softc *psc = tty_softc(tp);
454
455 if (psc->pts_flags & PTS_FINISHED) {
456 kn->kn_flags |= EV_EOF;
457 return (1);
458 } else {
459 kn->kn_data = ttydisc_getc_poll(tp);
460 return (kn->kn_data > 0);
461 }
462 }
463
464 static void
pts_kqops_write_detach(struct knote * kn)465 pts_kqops_write_detach(struct knote *kn)
466 {
467 struct file *fp = kn->kn_fp;
468 struct tty *tp = fp->f_data;
469 struct pts_softc *psc = tty_softc(tp);
470
471 knlist_remove(&psc->pts_inpoll.si_note, kn, 0);
472 }
473
474 static int
pts_kqops_write_event(struct knote * kn,long hint)475 pts_kqops_write_event(struct knote *kn, long hint)
476 {
477 struct file *fp = kn->kn_fp;
478 struct tty *tp = fp->f_data;
479 struct pts_softc *psc = tty_softc(tp);
480
481 if (psc->pts_flags & PTS_FINISHED) {
482 kn->kn_flags |= EV_EOF;
483 return (1);
484 } else {
485 kn->kn_data = ttydisc_rint_poll(tp);
486 return (kn->kn_data > 0);
487 }
488 }
489
490 static const struct filterops pts_kqops_read = {
491 .f_isfd = 1,
492 .f_detach = pts_kqops_read_detach,
493 .f_event = pts_kqops_read_event,
494 .f_copy = knote_triv_copy,
495 };
496 static const struct filterops pts_kqops_write = {
497 .f_isfd = 1,
498 .f_detach = pts_kqops_write_detach,
499 .f_event = pts_kqops_write_event,
500 .f_copy = knote_triv_copy,
501 };
502
503 static int
ptsdev_kqfilter(struct file * fp,struct knote * kn)504 ptsdev_kqfilter(struct file *fp, struct knote *kn)
505 {
506 struct tty *tp = fp->f_data;
507 struct pts_softc *psc = tty_softc(tp);
508 int error = 0;
509
510 tty_lock(tp);
511
512 switch (kn->kn_filter) {
513 case EVFILT_READ:
514 kn->kn_fop = &pts_kqops_read;
515 knlist_add(&psc->pts_outpoll.si_note, kn, 1);
516 break;
517 case EVFILT_WRITE:
518 kn->kn_fop = &pts_kqops_write;
519 knlist_add(&psc->pts_inpoll.si_note, kn, 1);
520 break;
521 default:
522 error = EINVAL;
523 break;
524 }
525
526 tty_unlock(tp);
527 return (error);
528 }
529
530 static int
ptsdev_stat(struct file * fp,struct stat * sb,struct ucred * active_cred)531 ptsdev_stat(struct file *fp, struct stat *sb, struct ucred *active_cred)
532 {
533 struct tty *tp = fp->f_data;
534 #ifdef PTS_EXTERNAL
535 struct pts_softc *psc = tty_softc(tp);
536 #endif /* PTS_EXTERNAL */
537 struct cdev *dev = tp->t_dev;
538
539 /*
540 * According to POSIX, we must implement an fstat(). This also
541 * makes this implementation compatible with Linux binaries,
542 * because Linux calls fstat() on the pseudo-terminal master to
543 * obtain st_rdev.
544 *
545 * XXX: POSIX also mentions we must fill in st_dev, but how?
546 */
547
548 bzero(sb, sizeof *sb);
549 #ifdef PTS_EXTERNAL
550 if (psc->pts_cdev != NULL)
551 sb->st_ino = sb->st_rdev = dev2udev(psc->pts_cdev);
552 else
553 #endif /* PTS_EXTERNAL */
554 sb->st_ino = sb->st_rdev = tty_udev(tp);
555
556 sb->st_atim = dev->si_atime;
557 sb->st_ctim = dev->si_ctime;
558 sb->st_mtim = dev->si_mtime;
559 sb->st_uid = dev->si_uid;
560 sb->st_gid = dev->si_gid;
561 sb->st_mode = dev->si_mode | S_IFCHR;
562
563 return (0);
564 }
565
566 static int
ptsdev_close(struct file * fp,struct thread * td)567 ptsdev_close(struct file *fp, struct thread *td)
568 {
569 struct tty *tp = fp->f_data;
570
571 /* Deallocate TTY device. */
572 tty_lock(tp);
573 tty_rel_gone(tp);
574
575 /*
576 * Open of /dev/ptmx or /dev/ptyXX changes the type of file
577 * from DTYPE_VNODE to DTYPE_PTS. vn_open() increases vnode
578 * use count, we need to decrement it, and possibly do other
579 * required cleanup.
580 */
581 if (fp->f_vnode != NULL)
582 return (vnops.fo_close(fp, td));
583
584 return (0);
585 }
586
587 static int
ptsdev_fill_kinfo(struct file * fp,struct kinfo_file * kif,struct filedesc * fdp)588 ptsdev_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp)
589 {
590 struct tty *tp;
591
592 kif->kf_type = KF_TYPE_PTS;
593 tp = fp->f_data;
594 kif->kf_un.kf_pts.kf_pts_dev = tty_udev(tp);
595 kif->kf_un.kf_pts.kf_pts_dev_freebsd11 =
596 kif->kf_un.kf_pts.kf_pts_dev; /* truncate */
597 strlcpy(kif->kf_path, tty_devname(tp), sizeof(kif->kf_path));
598 return (0);
599 }
600
601 static const struct fileops ptsdev_ops = {
602 .fo_read = ptsdev_read,
603 .fo_write = ptsdev_write,
604 .fo_truncate = invfo_truncate,
605 .fo_ioctl = ptsdev_ioctl,
606 .fo_poll = ptsdev_poll,
607 .fo_kqfilter = ptsdev_kqfilter,
608 .fo_stat = ptsdev_stat,
609 .fo_close = ptsdev_close,
610 .fo_chmod = invfo_chmod,
611 .fo_chown = invfo_chown,
612 .fo_sendfile = invfo_sendfile,
613 .fo_fill_kinfo = ptsdev_fill_kinfo,
614 .fo_cmp = file_kcmp_generic,
615 .fo_flags = DFLAG_PASSABLE,
616 };
617
618 /*
619 * Driver-side hooks.
620 */
621
622 static void
ptsdrv_outwakeup(struct tty * tp)623 ptsdrv_outwakeup(struct tty *tp)
624 {
625 struct pts_softc *psc = tty_softc(tp);
626
627 cv_broadcast(&psc->pts_outwait);
628 selwakeup(&psc->pts_outpoll);
629 KNOTE_LOCKED(&psc->pts_outpoll.si_note, 0);
630 }
631
632 static void
ptsdrv_inwakeup(struct tty * tp)633 ptsdrv_inwakeup(struct tty *tp)
634 {
635 struct pts_softc *psc = tty_softc(tp);
636
637 cv_broadcast(&psc->pts_inwait);
638 selwakeup(&psc->pts_inpoll);
639 KNOTE_LOCKED(&psc->pts_inpoll.si_note, 0);
640 }
641
642 static int
ptsdrv_open(struct tty * tp)643 ptsdrv_open(struct tty *tp)
644 {
645 struct pts_softc *psc = tty_softc(tp);
646
647 psc->pts_flags &= ~PTS_FINISHED;
648
649 return (0);
650 }
651
652 static void
ptsdrv_close(struct tty * tp)653 ptsdrv_close(struct tty *tp)
654 {
655 struct pts_softc *psc = tty_softc(tp);
656
657 /* Wake up any blocked readers/writers. */
658 psc->pts_flags |= PTS_FINISHED;
659 ptsdrv_outwakeup(tp);
660 ptsdrv_inwakeup(tp);
661 }
662
663 static void
ptsdrv_pktnotify(struct tty * tp,char event)664 ptsdrv_pktnotify(struct tty *tp, char event)
665 {
666 struct pts_softc *psc = tty_softc(tp);
667
668 /*
669 * Clear conflicting flags.
670 */
671
672 switch (event) {
673 case TIOCPKT_STOP:
674 psc->pts_pkt &= ~TIOCPKT_START;
675 break;
676 case TIOCPKT_START:
677 psc->pts_pkt &= ~TIOCPKT_STOP;
678 break;
679 case TIOCPKT_NOSTOP:
680 psc->pts_pkt &= ~TIOCPKT_DOSTOP;
681 break;
682 case TIOCPKT_DOSTOP:
683 psc->pts_pkt &= ~TIOCPKT_NOSTOP;
684 break;
685 }
686
687 psc->pts_pkt |= event;
688 ptsdrv_outwakeup(tp);
689 }
690
691 static void
ptsdrv_free(void * softc)692 ptsdrv_free(void *softc)
693 {
694 struct pts_softc *psc = softc;
695
696 /* Make device number available again. */
697 if (psc->pts_unit >= 0)
698 free_unr(pts_pool, psc->pts_unit);
699
700 chgptscnt(psc->pts_cred->cr_ruidinfo, -1, 0);
701 racct_sub_cred(psc->pts_cred, RACCT_NPTS, 1);
702 crfree(psc->pts_cred);
703
704 seldrain(&psc->pts_inpoll);
705 seldrain(&psc->pts_outpoll);
706 knlist_destroy(&psc->pts_inpoll.si_note);
707 knlist_destroy(&psc->pts_outpoll.si_note);
708
709 #ifdef PTS_EXTERNAL
710 /* Destroy master device as well. */
711 if (psc->pts_cdev != NULL)
712 destroy_dev_sched(psc->pts_cdev);
713 #endif /* PTS_EXTERNAL */
714
715 free(psc, M_PTS);
716 }
717
718 static struct ttydevsw pts_class = {
719 .tsw_flags = TF_NOPREFIX,
720 .tsw_outwakeup = ptsdrv_outwakeup,
721 .tsw_inwakeup = ptsdrv_inwakeup,
722 .tsw_open = ptsdrv_open,
723 .tsw_close = ptsdrv_close,
724 .tsw_pktnotify = ptsdrv_pktnotify,
725 .tsw_free = ptsdrv_free,
726 };
727
728 #ifndef PTS_EXTERNAL
729 static
730 #endif /* !PTS_EXTERNAL */
731 int
pts_alloc(int fflags,struct thread * td,struct file * fp)732 pts_alloc(int fflags, struct thread *td, struct file *fp)
733 {
734 int unit, ok, error;
735 struct tty *tp;
736 struct pts_softc *psc;
737 struct proc *p = td->td_proc;
738 struct ucred *cred = td->td_ucred;
739
740 /* Resource limiting. */
741 PROC_LOCK(p);
742 error = racct_add(p, RACCT_NPTS, 1);
743 if (error != 0) {
744 PROC_UNLOCK(p);
745 return (EAGAIN);
746 }
747 ok = chgptscnt(cred->cr_ruidinfo, 1, lim_cur(td, RLIMIT_NPTS));
748 if (!ok) {
749 racct_sub(p, RACCT_NPTS, 1);
750 PROC_UNLOCK(p);
751 return (EAGAIN);
752 }
753 PROC_UNLOCK(p);
754
755 /* Try to allocate a new pts unit number. */
756 unit = alloc_unr(pts_pool);
757 if (unit < 0) {
758 racct_sub(p, RACCT_NPTS, 1);
759 chgptscnt(cred->cr_ruidinfo, -1, 0);
760 return (EAGAIN);
761 }
762
763 /* Allocate TTY and softc. */
764 psc = malloc(sizeof(struct pts_softc), M_PTS, M_WAITOK|M_ZERO);
765 cv_init(&psc->pts_inwait, "ptsin");
766 cv_init(&psc->pts_outwait, "ptsout");
767
768 psc->pts_unit = unit;
769 psc->pts_cred = crhold(cred);
770
771 tp = tty_alloc(&pts_class, psc);
772 knlist_init_mtx(&psc->pts_inpoll.si_note, tp->t_mtx);
773 knlist_init_mtx(&psc->pts_outpoll.si_note, tp->t_mtx);
774
775 /* Expose the slave device as well. */
776 tty_makedev(tp, td->td_ucred, "pts/%u", psc->pts_unit);
777
778 finit(fp, fflags, DTYPE_PTS, tp, &ptsdev_ops);
779
780 return (0);
781 }
782
783 #ifdef PTS_EXTERNAL
784 int
pts_alloc_external(int fflags,struct thread * td,struct file * fp,struct cdev * dev,const char * name)785 pts_alloc_external(int fflags, struct thread *td, struct file *fp,
786 struct cdev *dev, const char *name)
787 {
788 int ok, error;
789 struct tty *tp;
790 struct pts_softc *psc;
791 struct proc *p = td->td_proc;
792 struct ucred *cred = td->td_ucred;
793
794 /* Resource limiting. */
795 PROC_LOCK(p);
796 error = racct_add(p, RACCT_NPTS, 1);
797 if (error != 0) {
798 PROC_UNLOCK(p);
799 return (EAGAIN);
800 }
801 ok = chgptscnt(cred->cr_ruidinfo, 1, lim_cur(td, RLIMIT_NPTS));
802 if (!ok) {
803 racct_sub(p, RACCT_NPTS, 1);
804 PROC_UNLOCK(p);
805 return (EAGAIN);
806 }
807 PROC_UNLOCK(p);
808
809 /* Allocate TTY and softc. */
810 psc = malloc(sizeof(struct pts_softc), M_PTS, M_WAITOK|M_ZERO);
811 cv_init(&psc->pts_inwait, "ptsin");
812 cv_init(&psc->pts_outwait, "ptsout");
813
814 psc->pts_unit = -1;
815 psc->pts_cdev = dev;
816 psc->pts_cred = crhold(cred);
817
818 tp = tty_alloc(&pts_class, psc);
819 knlist_init_mtx(&psc->pts_inpoll.si_note, tp->t_mtx);
820 knlist_init_mtx(&psc->pts_outpoll.si_note, tp->t_mtx);
821
822 /* Expose the slave device as well. */
823 tty_makedev(tp, td->td_ucred, "%s", name);
824
825 finit(fp, fflags, DTYPE_PTS, tp, &ptsdev_ops);
826
827 return (0);
828 }
829 #endif /* PTS_EXTERNAL */
830
831 int
sys_posix_openpt(struct thread * td,struct posix_openpt_args * uap)832 sys_posix_openpt(struct thread *td, struct posix_openpt_args *uap)
833 {
834 int error, fd;
835 struct file *fp;
836
837 /*
838 * POSIX states it's unspecified when other flags are passed. We
839 * don't allow this.
840 */
841 if (uap->flags & ~(O_RDWR|O_NOCTTY|O_CLOEXEC))
842 return (EINVAL);
843
844 error = falloc(td, &fp, &fd, uap->flags);
845 if (error)
846 return (error);
847
848 /* Allocate the actual pseudo-TTY. */
849 error = pts_alloc(FFLAGS(uap->flags & O_ACCMODE), td, fp);
850 if (error != 0) {
851 fdclose(td, fp, fd);
852 fdrop(fp, td);
853 return (error);
854 }
855
856 /* Pass it back to userspace. */
857 td->td_retval[0] = fd;
858 fdrop(fp, td);
859
860 return (0);
861 }
862
863 static void
pts_init(void * unused)864 pts_init(void *unused)
865 {
866
867 pts_pool = new_unrhdr(0, INT_MAX, NULL);
868 }
869
870 SYSINIT(pts, SI_SUB_DRIVERS, SI_ORDER_MIDDLE, pts_init, NULL);
871