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