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 };
495 static const struct filterops pts_kqops_write = {
496 .f_isfd = 1,
497 .f_detach = pts_kqops_write_detach,
498 .f_event = pts_kqops_write_event,
499 };
500
501 static int
ptsdev_kqfilter(struct file * fp,struct knote * kn)502 ptsdev_kqfilter(struct file *fp, struct knote *kn)
503 {
504 struct tty *tp = fp->f_data;
505 struct pts_softc *psc = tty_softc(tp);
506 int error = 0;
507
508 tty_lock(tp);
509
510 switch (kn->kn_filter) {
511 case EVFILT_READ:
512 kn->kn_fop = &pts_kqops_read;
513 knlist_add(&psc->pts_outpoll.si_note, kn, 1);
514 break;
515 case EVFILT_WRITE:
516 kn->kn_fop = &pts_kqops_write;
517 knlist_add(&psc->pts_inpoll.si_note, kn, 1);
518 break;
519 default:
520 error = EINVAL;
521 break;
522 }
523
524 tty_unlock(tp);
525 return (error);
526 }
527
528 static int
ptsdev_stat(struct file * fp,struct stat * sb,struct ucred * active_cred)529 ptsdev_stat(struct file *fp, struct stat *sb, struct ucred *active_cred)
530 {
531 struct tty *tp = fp->f_data;
532 #ifdef PTS_EXTERNAL
533 struct pts_softc *psc = tty_softc(tp);
534 #endif /* PTS_EXTERNAL */
535 struct cdev *dev = tp->t_dev;
536
537 /*
538 * According to POSIX, we must implement an fstat(). This also
539 * makes this implementation compatible with Linux binaries,
540 * because Linux calls fstat() on the pseudo-terminal master to
541 * obtain st_rdev.
542 *
543 * XXX: POSIX also mentions we must fill in st_dev, but how?
544 */
545
546 bzero(sb, sizeof *sb);
547 #ifdef PTS_EXTERNAL
548 if (psc->pts_cdev != NULL)
549 sb->st_ino = sb->st_rdev = dev2udev(psc->pts_cdev);
550 else
551 #endif /* PTS_EXTERNAL */
552 sb->st_ino = sb->st_rdev = tty_udev(tp);
553
554 sb->st_atim = dev->si_atime;
555 sb->st_ctim = dev->si_ctime;
556 sb->st_mtim = dev->si_mtime;
557 sb->st_uid = dev->si_uid;
558 sb->st_gid = dev->si_gid;
559 sb->st_mode = dev->si_mode | S_IFCHR;
560
561 return (0);
562 }
563
564 static int
ptsdev_close(struct file * fp,struct thread * td)565 ptsdev_close(struct file *fp, struct thread *td)
566 {
567 struct tty *tp = fp->f_data;
568
569 /* Deallocate TTY device. */
570 tty_lock(tp);
571 tty_rel_gone(tp);
572
573 /*
574 * Open of /dev/ptmx or /dev/ptyXX changes the type of file
575 * from DTYPE_VNODE to DTYPE_PTS. vn_open() increases vnode
576 * use count, we need to decrement it, and possibly do other
577 * required cleanup.
578 */
579 if (fp->f_vnode != NULL)
580 return (vnops.fo_close(fp, td));
581
582 return (0);
583 }
584
585 static int
ptsdev_fill_kinfo(struct file * fp,struct kinfo_file * kif,struct filedesc * fdp)586 ptsdev_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp)
587 {
588 struct tty *tp;
589
590 kif->kf_type = KF_TYPE_PTS;
591 tp = fp->f_data;
592 kif->kf_un.kf_pts.kf_pts_dev = tty_udev(tp);
593 kif->kf_un.kf_pts.kf_pts_dev_freebsd11 =
594 kif->kf_un.kf_pts.kf_pts_dev; /* truncate */
595 strlcpy(kif->kf_path, tty_devname(tp), sizeof(kif->kf_path));
596 return (0);
597 }
598
599 static const struct fileops ptsdev_ops = {
600 .fo_read = ptsdev_read,
601 .fo_write = ptsdev_write,
602 .fo_truncate = invfo_truncate,
603 .fo_ioctl = ptsdev_ioctl,
604 .fo_poll = ptsdev_poll,
605 .fo_kqfilter = ptsdev_kqfilter,
606 .fo_stat = ptsdev_stat,
607 .fo_close = ptsdev_close,
608 .fo_chmod = invfo_chmod,
609 .fo_chown = invfo_chown,
610 .fo_sendfile = invfo_sendfile,
611 .fo_fill_kinfo = ptsdev_fill_kinfo,
612 .fo_cmp = file_kcmp_generic,
613 .fo_flags = DFLAG_PASSABLE,
614 };
615
616 /*
617 * Driver-side hooks.
618 */
619
620 static void
ptsdrv_outwakeup(struct tty * tp)621 ptsdrv_outwakeup(struct tty *tp)
622 {
623 struct pts_softc *psc = tty_softc(tp);
624
625 cv_broadcast(&psc->pts_outwait);
626 selwakeup(&psc->pts_outpoll);
627 KNOTE_LOCKED(&psc->pts_outpoll.si_note, 0);
628 }
629
630 static void
ptsdrv_inwakeup(struct tty * tp)631 ptsdrv_inwakeup(struct tty *tp)
632 {
633 struct pts_softc *psc = tty_softc(tp);
634
635 cv_broadcast(&psc->pts_inwait);
636 selwakeup(&psc->pts_inpoll);
637 KNOTE_LOCKED(&psc->pts_inpoll.si_note, 0);
638 }
639
640 static int
ptsdrv_open(struct tty * tp)641 ptsdrv_open(struct tty *tp)
642 {
643 struct pts_softc *psc = tty_softc(tp);
644
645 psc->pts_flags &= ~PTS_FINISHED;
646
647 return (0);
648 }
649
650 static void
ptsdrv_close(struct tty * tp)651 ptsdrv_close(struct tty *tp)
652 {
653 struct pts_softc *psc = tty_softc(tp);
654
655 /* Wake up any blocked readers/writers. */
656 psc->pts_flags |= PTS_FINISHED;
657 ptsdrv_outwakeup(tp);
658 ptsdrv_inwakeup(tp);
659 }
660
661 static void
ptsdrv_pktnotify(struct tty * tp,char event)662 ptsdrv_pktnotify(struct tty *tp, char event)
663 {
664 struct pts_softc *psc = tty_softc(tp);
665
666 /*
667 * Clear conflicting flags.
668 */
669
670 switch (event) {
671 case TIOCPKT_STOP:
672 psc->pts_pkt &= ~TIOCPKT_START;
673 break;
674 case TIOCPKT_START:
675 psc->pts_pkt &= ~TIOCPKT_STOP;
676 break;
677 case TIOCPKT_NOSTOP:
678 psc->pts_pkt &= ~TIOCPKT_DOSTOP;
679 break;
680 case TIOCPKT_DOSTOP:
681 psc->pts_pkt &= ~TIOCPKT_NOSTOP;
682 break;
683 }
684
685 psc->pts_pkt |= event;
686 ptsdrv_outwakeup(tp);
687 }
688
689 static void
ptsdrv_free(void * softc)690 ptsdrv_free(void *softc)
691 {
692 struct pts_softc *psc = softc;
693
694 /* Make device number available again. */
695 if (psc->pts_unit >= 0)
696 free_unr(pts_pool, psc->pts_unit);
697
698 chgptscnt(psc->pts_cred->cr_ruidinfo, -1, 0);
699 racct_sub_cred(psc->pts_cred, RACCT_NPTS, 1);
700 crfree(psc->pts_cred);
701
702 seldrain(&psc->pts_inpoll);
703 seldrain(&psc->pts_outpoll);
704 knlist_destroy(&psc->pts_inpoll.si_note);
705 knlist_destroy(&psc->pts_outpoll.si_note);
706
707 #ifdef PTS_EXTERNAL
708 /* Destroy master device as well. */
709 if (psc->pts_cdev != NULL)
710 destroy_dev_sched(psc->pts_cdev);
711 #endif /* PTS_EXTERNAL */
712
713 free(psc, M_PTS);
714 }
715
716 static struct ttydevsw pts_class = {
717 .tsw_flags = TF_NOPREFIX,
718 .tsw_outwakeup = ptsdrv_outwakeup,
719 .tsw_inwakeup = ptsdrv_inwakeup,
720 .tsw_open = ptsdrv_open,
721 .tsw_close = ptsdrv_close,
722 .tsw_pktnotify = ptsdrv_pktnotify,
723 .tsw_free = ptsdrv_free,
724 };
725
726 #ifndef PTS_EXTERNAL
727 static
728 #endif /* !PTS_EXTERNAL */
729 int
pts_alloc(int fflags,struct thread * td,struct file * fp)730 pts_alloc(int fflags, struct thread *td, struct file *fp)
731 {
732 int unit, ok, error;
733 struct tty *tp;
734 struct pts_softc *psc;
735 struct proc *p = td->td_proc;
736 struct ucred *cred = td->td_ucred;
737
738 /* Resource limiting. */
739 PROC_LOCK(p);
740 error = racct_add(p, RACCT_NPTS, 1);
741 if (error != 0) {
742 PROC_UNLOCK(p);
743 return (EAGAIN);
744 }
745 ok = chgptscnt(cred->cr_ruidinfo, 1, lim_cur(td, RLIMIT_NPTS));
746 if (!ok) {
747 racct_sub(p, RACCT_NPTS, 1);
748 PROC_UNLOCK(p);
749 return (EAGAIN);
750 }
751 PROC_UNLOCK(p);
752
753 /* Try to allocate a new pts unit number. */
754 unit = alloc_unr(pts_pool);
755 if (unit < 0) {
756 racct_sub(p, RACCT_NPTS, 1);
757 chgptscnt(cred->cr_ruidinfo, -1, 0);
758 return (EAGAIN);
759 }
760
761 /* Allocate TTY and softc. */
762 psc = malloc(sizeof(struct pts_softc), M_PTS, M_WAITOK|M_ZERO);
763 cv_init(&psc->pts_inwait, "ptsin");
764 cv_init(&psc->pts_outwait, "ptsout");
765
766 psc->pts_unit = unit;
767 psc->pts_cred = crhold(cred);
768
769 tp = tty_alloc(&pts_class, psc);
770 knlist_init_mtx(&psc->pts_inpoll.si_note, tp->t_mtx);
771 knlist_init_mtx(&psc->pts_outpoll.si_note, tp->t_mtx);
772
773 /* Expose the slave device as well. */
774 tty_makedev(tp, td->td_ucred, "pts/%u", psc->pts_unit);
775
776 finit(fp, fflags, DTYPE_PTS, tp, &ptsdev_ops);
777
778 return (0);
779 }
780
781 #ifdef PTS_EXTERNAL
782 int
pts_alloc_external(int fflags,struct thread * td,struct file * fp,struct cdev * dev,const char * name)783 pts_alloc_external(int fflags, struct thread *td, struct file *fp,
784 struct cdev *dev, const char *name)
785 {
786 int ok, error;
787 struct tty *tp;
788 struct pts_softc *psc;
789 struct proc *p = td->td_proc;
790 struct ucred *cred = td->td_ucred;
791
792 /* Resource limiting. */
793 PROC_LOCK(p);
794 error = racct_add(p, RACCT_NPTS, 1);
795 if (error != 0) {
796 PROC_UNLOCK(p);
797 return (EAGAIN);
798 }
799 ok = chgptscnt(cred->cr_ruidinfo, 1, lim_cur(td, RLIMIT_NPTS));
800 if (!ok) {
801 racct_sub(p, RACCT_NPTS, 1);
802 PROC_UNLOCK(p);
803 return (EAGAIN);
804 }
805 PROC_UNLOCK(p);
806
807 /* Allocate TTY and softc. */
808 psc = malloc(sizeof(struct pts_softc), M_PTS, M_WAITOK|M_ZERO);
809 cv_init(&psc->pts_inwait, "ptsin");
810 cv_init(&psc->pts_outwait, "ptsout");
811
812 psc->pts_unit = -1;
813 psc->pts_cdev = dev;
814 psc->pts_cred = crhold(cred);
815
816 tp = tty_alloc(&pts_class, psc);
817 knlist_init_mtx(&psc->pts_inpoll.si_note, tp->t_mtx);
818 knlist_init_mtx(&psc->pts_outpoll.si_note, tp->t_mtx);
819
820 /* Expose the slave device as well. */
821 tty_makedev(tp, td->td_ucred, "%s", name);
822
823 finit(fp, fflags, DTYPE_PTS, tp, &ptsdev_ops);
824
825 return (0);
826 }
827 #endif /* PTS_EXTERNAL */
828
829 int
sys_posix_openpt(struct thread * td,struct posix_openpt_args * uap)830 sys_posix_openpt(struct thread *td, struct posix_openpt_args *uap)
831 {
832 int error, fd;
833 struct file *fp;
834
835 /*
836 * POSIX states it's unspecified when other flags are passed. We
837 * don't allow this.
838 */
839 if (uap->flags & ~(O_RDWR|O_NOCTTY|O_CLOEXEC))
840 return (EINVAL);
841
842 error = falloc(td, &fp, &fd, uap->flags);
843 if (error)
844 return (error);
845
846 /* Allocate the actual pseudo-TTY. */
847 error = pts_alloc(FFLAGS(uap->flags & O_ACCMODE), td, fp);
848 if (error != 0) {
849 fdclose(td, fp, fd);
850 fdrop(fp, td);
851 return (error);
852 }
853
854 /* Pass it back to userspace. */
855 td->td_retval[0] = fd;
856 fdrop(fp, td);
857
858 return (0);
859 }
860
861 static void
pts_init(void * unused)862 pts_init(void *unused)
863 {
864
865 pts_pool = new_unrhdr(0, INT_MAX, NULL);
866 }
867
868 SYSINIT(pts, SI_SUB_DRIVERS, SI_ORDER_MIDDLE, pts_init, NULL);
869