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 if (cmd == TIOCNOTTY || cmd == TIOCSCTTY || cmd == TIOCSPGRP)
265 return (ttydev_ioctl_proctree(tp, cmd, data, td));
266
267 switch (cmd) {
268 case FIODTYPE:
269 *(int *)data = D_TTY;
270 return (0);
271 case FIONBIO:
272 /* This device supports non-blocking operation. */
273 return (0);
274 case FIONREAD:
275 tty_lock(tp);
276 *(int *)data = ttydisc_getc_poll(tp);
277 tty_unlock(tp);
278 return (0);
279 case FIODGNAME:
280 #ifdef COMPAT_FREEBSD32
281 case FIODGNAME_32:
282 #endif
283 {
284 struct fiodgname_arg *fgn;
285 const char *p;
286 int i;
287
288 /* Reverse device name lookups, for ptsname() and ttyname(). */
289 fgn = data;
290 p = tty_devname(tp);
291 i = strlen(p) + 1;
292 if (i > fgn->len)
293 return (EINVAL);
294 return (copyout(p, fiodgname_buf_get_ptr(fgn, cmd), i));
295 }
296
297 /*
298 * We need to implement TIOCGPGRP and TIOCGSID here again. When
299 * called on the pseudo-terminal master, it should not check if
300 * the terminal is the foreground terminal of the calling
301 * process.
302 *
303 * TIOCGETA is also implemented here. Various Linux PTY routines
304 * often call isatty(), which is implemented by tcgetattr().
305 */
306 #ifdef PTS_LINUX
307 case TIOCGETA:
308 /* Obtain terminal flags through tcgetattr(). */
309 tty_lock(tp);
310 *(struct termios*)data = tp->t_termios;
311 tty_unlock(tp);
312 return (0);
313 #endif /* PTS_LINUX */
314 case TIOCSETAF:
315 case TIOCSETAW:
316 /*
317 * We must make sure we turn tcsetattr() calls of TCSAFLUSH and
318 * TCSADRAIN into something different. If an application would
319 * call TCSAFLUSH or TCSADRAIN on the master descriptor, it may
320 * deadlock waiting for all data to be read.
321 */
322 cmd = TIOCSETA;
323 break;
324 #if defined(PTS_COMPAT) || defined(PTS_LINUX)
325 case TIOCGPTN:
326 /*
327 * Get the device unit number.
328 */
329 if (psc->pts_unit < 0)
330 return (ENOTTY);
331 *(unsigned int *)data = psc->pts_unit;
332 return (0);
333 #endif /* PTS_COMPAT || PTS_LINUX */
334 case TIOCGPGRP:
335 /* Get the foreground process group ID. */
336 tty_lock(tp);
337 if (tp->t_pgrp != NULL)
338 *(int *)data = tp->t_pgrp->pg_id;
339 else
340 *(int *)data = NO_PID;
341 tty_unlock(tp);
342 return (0);
343 case TIOCGSID:
344 /* Get the session leader process ID. */
345 tty_lock(tp);
346 if (tp->t_session == NULL)
347 error = ENOTTY;
348 else
349 *(int *)data = tp->t_session->s_sid;
350 tty_unlock(tp);
351 return (error);
352 case TIOCPTMASTER:
353 /* Yes, we are a pseudo-terminal master. */
354 return (0);
355 case TIOCSIG:
356 /* Signal the foreground process group. */
357 sig = *(int *)data;
358 if (sig < 1 || sig >= NSIG)
359 return (EINVAL);
360
361 tty_lock(tp);
362 tty_signal_pgrp(tp, sig);
363 tty_unlock(tp);
364 return (0);
365 case TIOCPKT:
366 /* Enable/disable packet mode. */
367 tty_lock(tp);
368 if (*(int *)data)
369 psc->pts_flags |= PTS_PKT;
370 else
371 psc->pts_flags &= ~PTS_PKT;
372 tty_unlock(tp);
373 return (0);
374 }
375
376 /* Just redirect this ioctl to the slave device. */
377 tty_lock(tp);
378 error = tty_ioctl(tp, cmd, data, fp->f_flag, td);
379 tty_unlock(tp);
380 if (error == ENOIOCTL)
381 error = ENOTTY;
382
383 return (error);
384 }
385
386 static int
ptsdev_poll(struct file * fp,int events,struct ucred * active_cred,struct thread * td)387 ptsdev_poll(struct file *fp, int events, struct ucred *active_cred,
388 struct thread *td)
389 {
390 struct tty *tp = fp->f_data;
391 struct pts_softc *psc = tty_softc(tp);
392 int revents = 0;
393
394 tty_lock(tp);
395
396 if (psc->pts_flags & PTS_FINISHED) {
397 /* Slave device is not opened. */
398 tty_unlock(tp);
399 return ((events & (POLLIN|POLLRDNORM)) | POLLHUP);
400 }
401
402 if (events & (POLLIN|POLLRDNORM)) {
403 /* See if we can getc something. */
404 if (ttydisc_getc_poll(tp) ||
405 (psc->pts_flags & PTS_PKT && psc->pts_pkt))
406 revents |= events & (POLLIN|POLLRDNORM);
407 }
408 if (events & (POLLOUT|POLLWRNORM)) {
409 /* See if we can rint something. */
410 if (ttydisc_rint_poll(tp))
411 revents |= events & (POLLOUT|POLLWRNORM);
412 }
413
414 /*
415 * No need to check for POLLHUP here. This device cannot be used
416 * as a callout device, which means we always have a carrier,
417 * because the master is.
418 */
419
420 if (revents == 0) {
421 /*
422 * This code might look misleading, but the naming of
423 * poll events on this side is the opposite of the slave
424 * device.
425 */
426 if (events & (POLLIN|POLLRDNORM))
427 selrecord(td, &psc->pts_outpoll);
428 if (events & (POLLOUT|POLLWRNORM))
429 selrecord(td, &psc->pts_inpoll);
430 }
431
432 tty_unlock(tp);
433
434 return (revents);
435 }
436
437 /*
438 * kqueue support.
439 */
440
441 static void
pts_kqops_read_detach(struct knote * kn)442 pts_kqops_read_detach(struct knote *kn)
443 {
444 struct file *fp = kn->kn_fp;
445 struct tty *tp = fp->f_data;
446 struct pts_softc *psc = tty_softc(tp);
447
448 knlist_remove(&psc->pts_outpoll.si_note, kn, 0);
449 }
450
451 static int
pts_kqops_read_event(struct knote * kn,long hint)452 pts_kqops_read_event(struct knote *kn, long hint)
453 {
454 struct file *fp = kn->kn_fp;
455 struct tty *tp = fp->f_data;
456 struct pts_softc *psc = tty_softc(tp);
457
458 if (psc->pts_flags & PTS_FINISHED) {
459 kn->kn_flags |= EV_EOF;
460 return (1);
461 } else {
462 kn->kn_data = ttydisc_getc_poll(tp);
463 return (kn->kn_data > 0);
464 }
465 }
466
467 static void
pts_kqops_write_detach(struct knote * kn)468 pts_kqops_write_detach(struct knote *kn)
469 {
470 struct file *fp = kn->kn_fp;
471 struct tty *tp = fp->f_data;
472 struct pts_softc *psc = tty_softc(tp);
473
474 knlist_remove(&psc->pts_inpoll.si_note, kn, 0);
475 }
476
477 static int
pts_kqops_write_event(struct knote * kn,long hint)478 pts_kqops_write_event(struct knote *kn, long hint)
479 {
480 struct file *fp = kn->kn_fp;
481 struct tty *tp = fp->f_data;
482 struct pts_softc *psc = tty_softc(tp);
483
484 if (psc->pts_flags & PTS_FINISHED) {
485 kn->kn_flags |= EV_EOF;
486 return (1);
487 } else {
488 kn->kn_data = ttydisc_rint_poll(tp);
489 return (kn->kn_data > 0);
490 }
491 }
492
493 static const struct filterops pts_kqops_read = {
494 .f_isfd = 1,
495 .f_detach = pts_kqops_read_detach,
496 .f_event = pts_kqops_read_event,
497 .f_copy = knote_triv_copy,
498 };
499 static const struct filterops pts_kqops_write = {
500 .f_isfd = 1,
501 .f_detach = pts_kqops_write_detach,
502 .f_event = pts_kqops_write_event,
503 .f_copy = knote_triv_copy,
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)534 ptsdev_stat(struct file *fp, struct stat *sb, struct ucred *active_cred)
535 {
536 struct tty *tp = fp->f_data;
537 #ifdef PTS_EXTERNAL
538 struct pts_softc *psc = tty_softc(tp);
539 #endif /* PTS_EXTERNAL */
540 struct cdev *dev = tp->t_dev;
541
542 /*
543 * According to POSIX, we must implement an fstat(). This also
544 * makes this implementation compatible with Linux binaries,
545 * because Linux calls fstat() on the pseudo-terminal master to
546 * obtain st_rdev.
547 *
548 * XXX: POSIX also mentions we must fill in st_dev, but how?
549 */
550
551 bzero(sb, sizeof *sb);
552 #ifdef PTS_EXTERNAL
553 if (psc->pts_cdev != NULL)
554 sb->st_ino = sb->st_rdev = dev2udev(psc->pts_cdev);
555 else
556 #endif /* PTS_EXTERNAL */
557 sb->st_ino = sb->st_rdev = tty_udev(tp);
558
559 sb->st_atim = dev->si_atime;
560 sb->st_ctim = dev->si_ctime;
561 sb->st_mtim = dev->si_mtime;
562 sb->st_uid = dev->si_uid;
563 sb->st_gid = dev->si_gid;
564 sb->st_mode = dev->si_mode | S_IFCHR;
565
566 return (0);
567 }
568
569 static int
ptsdev_close(struct file * fp,struct thread * td)570 ptsdev_close(struct file *fp, struct thread *td)
571 {
572 struct tty *tp = fp->f_data;
573
574 /* Deallocate TTY device. */
575 tty_lock(tp);
576 tty_rel_gone(tp);
577
578 /*
579 * Open of /dev/ptmx or /dev/ptyXX changes the type of file
580 * from DTYPE_VNODE to DTYPE_PTS. vn_open() increases vnode
581 * use count, we need to decrement it, and possibly do other
582 * required cleanup.
583 */
584 if (fp->f_vnode != NULL)
585 return (vnops.fo_close(fp, td));
586
587 return (0);
588 }
589
590 static int
ptsdev_fill_kinfo(struct file * fp,struct kinfo_file * kif,struct filedesc * fdp)591 ptsdev_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp)
592 {
593 struct tty *tp;
594
595 kif->kf_type = KF_TYPE_PTS;
596 tp = fp->f_data;
597 kif->kf_un.kf_pts.kf_pts_dev = tty_udev(tp);
598 kif->kf_un.kf_pts.kf_pts_dev_freebsd11 =
599 kif->kf_un.kf_pts.kf_pts_dev; /* truncate */
600 strlcpy(kif->kf_path, tty_devname(tp), sizeof(kif->kf_path));
601 return (0);
602 }
603
604 static const struct fileops ptsdev_ops = {
605 .fo_read = ptsdev_read,
606 .fo_write = ptsdev_write,
607 .fo_truncate = invfo_truncate,
608 .fo_ioctl = ptsdev_ioctl,
609 .fo_poll = ptsdev_poll,
610 .fo_kqfilter = ptsdev_kqfilter,
611 .fo_stat = ptsdev_stat,
612 .fo_close = ptsdev_close,
613 .fo_chmod = invfo_chmod,
614 .fo_chown = invfo_chown,
615 .fo_sendfile = invfo_sendfile,
616 .fo_fill_kinfo = ptsdev_fill_kinfo,
617 .fo_cmp = file_kcmp_generic,
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