2 * SPDX-License-Identifier: BSD-2-Clause
4 * Copyright (c) 2008 Ed Schouten <ed@FreeBSD.org>
7 * Portions of this software were developed under sponsorship from Snow
8 * B.V., the Netherlands.
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
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.
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
32 #include <sys/cdefs.h>
33 /* Add compatibility bits for FreeBSD. */
35 /* Add pty(4) compat bits. */
37 /* Add bits to make Linux binaries work. */
40 #include <sys/param.h>
42 #include <sys/condvar.h>
44 #include <sys/fcntl.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>
54 #include <sys/racct.h>
55 #include <sys/resourcevar.h>
56 #include <sys/serial.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>
64 #include <sys/ttycom.h>
68 #include <machine/stdarg.h>
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
76 static struct unrhdr *pts_pool;
78 static MALLOC_DEFINE(M_PTS, "pts", "pseudo tty device");
84 * (t) locked by tty_lock()
85 * (c) const until freeing
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. */
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(). */
100 struct cdev *pts_cdev; /* (c) Master device node. */
101 #endif /* PTS_EXTERNAL */
103 struct ucred *pts_cred; /* (c) Resource limit. */
107 * Controller-side file operations.
111 ptsdev_read(struct file *fp, struct uio *uio, struct ucred *active_cred,
112 int flags, struct thread *td)
114 struct tty *tp = fp->f_data;
115 struct pts_softc *psc = tty_softc(tp);
119 if (uio->uio_resid == 0)
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).
130 if (psc->pts_flags & PTS_PKT && psc->pts_pkt) {
135 error = ureadc(pkt, uio);
140 * Transmit regular data.
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.
147 if (ttydisc_getc_poll(tp)) {
148 if (psc->pts_flags & PTS_PKT) {
150 * XXX: Small race. Fortunately PTY
151 * consumers aren't multithreaded.
155 error = ureadc(TIOCPKT_DATA, uio);
161 error = ttydisc_getc_uio(tp, uio);
165 /* Maybe the device isn't used anyway. */
166 if (psc->pts_flags & PTS_FINISHED)
169 /* Wait for more data. */
170 if (fp->f_flag & O_NONBLOCK) {
174 error = cv_wait_sig(&psc->pts_outwait, tp->t_mtx);
185 ptsdev_write(struct file *fp, struct uio *uio, struct ucred *active_cred,
186 int flags, struct thread *td)
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;
194 if (uio->uio_resid == 0)
199 iblen = MIN(uio->uio_resid, sizeof ib);
200 error = uiomove(ib, iblen, uio);
209 * When possible, avoid the slow path. rint_bypass()
210 * copies all input to the input queue at once.
214 rintlen = ttydisc_rint_simple(tp, ibstart, iblen);
218 /* All data written. */
222 /* Maybe the device isn't used anyway. */
223 if (psc->pts_flags & PTS_FINISHED) {
228 /* Wait for more data. */
229 if (fp->f_flag & O_NONBLOCK) {
234 /* Wake up users on the slave side. */
235 ttydisc_rint_done(tp);
236 error = cv_wait_sig(&psc->pts_inwait, tp->t_mtx);
241 if (uio->uio_resid == 0)
246 done: ttydisc_rint_done(tp);
250 * Don't account for the part of the buffer that we couldn't
253 uio->uio_resid += iblen;
258 ptsdev_ioctl(struct file *fp, u_long cmd, void *data,
259 struct ucred *active_cred, struct thread *td)
261 struct tty *tp = fp->f_data;
262 struct pts_softc *psc = tty_softc(tp);
267 *(int *)data = D_TTY;
270 /* This device supports non-blocking operation. */
274 if (psc->pts_flags & PTS_FINISHED) {
275 /* Force read() to be called. */
278 *(int *)data = ttydisc_getc_poll(tp);
283 #ifdef COMPAT_FREEBSD32
287 struct fiodgname_arg *fgn;
291 /* Reverse device name lookups, for ptsname() and ttyname(). */
297 return (copyout(p, fiodgname_buf_get_ptr(fgn, cmd), i));
301 * We need to implement TIOCGPGRP and TIOCGSID here again. When
302 * called on the pseudo-terminal master, it should not check if
303 * the terminal is the foreground terminal of the calling
306 * TIOCGETA is also implemented here. Various Linux PTY routines
307 * often call isatty(), which is implemented by tcgetattr().
311 /* Obtain terminal flags through tcgetattr(). */
313 *(struct termios*)data = tp->t_termios;
316 #endif /* PTS_LINUX */
320 * We must make sure we turn tcsetattr() calls of TCSAFLUSH and
321 * TCSADRAIN into something different. If an application would
322 * call TCSAFLUSH or TCSADRAIN on the master descriptor, it may
323 * deadlock waiting for all data to be read.
327 #if defined(PTS_COMPAT) || defined(PTS_LINUX)
330 * Get the device unit number.
332 if (psc->pts_unit < 0)
334 *(unsigned int *)data = psc->pts_unit;
336 #endif /* PTS_COMPAT || PTS_LINUX */
338 /* Get the foreground process group ID. */
340 if (tp->t_pgrp != NULL)
341 *(int *)data = tp->t_pgrp->pg_id;
343 *(int *)data = NO_PID;
347 /* Get the session leader process ID. */
349 if (tp->t_session == NULL)
352 *(int *)data = tp->t_session->s_sid;
356 /* Yes, we are a pseudo-terminal master. */
359 /* Signal the foreground process group. */
361 if (sig < 1 || sig >= NSIG)
365 tty_signal_pgrp(tp, sig);
369 /* Enable/disable packet mode. */
372 psc->pts_flags |= PTS_PKT;
374 psc->pts_flags &= ~PTS_PKT;
379 /* Just redirect this ioctl to the slave device. */
381 error = tty_ioctl(tp, cmd, data, fp->f_flag, td);
383 if (error == ENOIOCTL)
390 ptsdev_poll(struct file *fp, int events, struct ucred *active_cred,
393 struct tty *tp = fp->f_data;
394 struct pts_softc *psc = tty_softc(tp);
399 if (psc->pts_flags & PTS_FINISHED) {
400 /* Slave device is not opened. */
402 return ((events & (POLLIN|POLLRDNORM)) | POLLHUP);
405 if (events & (POLLIN|POLLRDNORM)) {
406 /* See if we can getc something. */
407 if (ttydisc_getc_poll(tp) ||
408 (psc->pts_flags & PTS_PKT && psc->pts_pkt))
409 revents |= events & (POLLIN|POLLRDNORM);
411 if (events & (POLLOUT|POLLWRNORM)) {
412 /* See if we can rint something. */
413 if (ttydisc_rint_poll(tp))
414 revents |= events & (POLLOUT|POLLWRNORM);
418 * No need to check for POLLHUP here. This device cannot be used
419 * as a callout device, which means we always have a carrier,
420 * because the master is.
425 * This code might look misleading, but the naming of
426 * poll events on this side is the opposite of the slave
429 if (events & (POLLIN|POLLRDNORM))
430 selrecord(td, &psc->pts_outpoll);
431 if (events & (POLLOUT|POLLWRNORM))
432 selrecord(td, &psc->pts_inpoll);
445 pts_kqops_read_detach(struct knote *kn)
447 struct file *fp = kn->kn_fp;
448 struct tty *tp = fp->f_data;
449 struct pts_softc *psc = tty_softc(tp);
451 knlist_remove(&psc->pts_outpoll.si_note, kn, 0);
455 pts_kqops_read_event(struct knote *kn, long hint)
457 struct file *fp = kn->kn_fp;
458 struct tty *tp = fp->f_data;
459 struct pts_softc *psc = tty_softc(tp);
461 if (psc->pts_flags & PTS_FINISHED) {
462 kn->kn_flags |= EV_EOF;
465 kn->kn_data = ttydisc_getc_poll(tp);
466 return (kn->kn_data > 0);
471 pts_kqops_write_detach(struct knote *kn)
473 struct file *fp = kn->kn_fp;
474 struct tty *tp = fp->f_data;
475 struct pts_softc *psc = tty_softc(tp);
477 knlist_remove(&psc->pts_inpoll.si_note, kn, 0);
481 pts_kqops_write_event(struct knote *kn, long hint)
483 struct file *fp = kn->kn_fp;
484 struct tty *tp = fp->f_data;
485 struct pts_softc *psc = tty_softc(tp);
487 if (psc->pts_flags & PTS_FINISHED) {
488 kn->kn_flags |= EV_EOF;
491 kn->kn_data = ttydisc_rint_poll(tp);
492 return (kn->kn_data > 0);
496 static struct filterops pts_kqops_read = {
498 .f_detach = pts_kqops_read_detach,
499 .f_event = pts_kqops_read_event,
501 static struct filterops pts_kqops_write = {
503 .f_detach = pts_kqops_write_detach,
504 .f_event = pts_kqops_write_event,
508 ptsdev_kqfilter(struct file *fp, struct knote *kn)
510 struct tty *tp = fp->f_data;
511 struct pts_softc *psc = tty_softc(tp);
516 switch (kn->kn_filter) {
518 kn->kn_fop = &pts_kqops_read;
519 knlist_add(&psc->pts_outpoll.si_note, kn, 1);
522 kn->kn_fop = &pts_kqops_write;
523 knlist_add(&psc->pts_inpoll.si_note, kn, 1);
535 ptsdev_stat(struct file *fp, struct stat *sb, struct ucred *active_cred,
538 struct tty *tp = fp->f_data;
540 struct pts_softc *psc = tty_softc(tp);
541 #endif /* PTS_EXTERNAL */
542 struct cdev *dev = tp->t_dev;
545 * According to POSIX, we must implement an fstat(). This also
546 * makes this implementation compatible with Linux binaries,
547 * because Linux calls fstat() on the pseudo-terminal master to
550 * XXX: POSIX also mentions we must fill in st_dev, but how?
553 bzero(sb, sizeof *sb);
555 if (psc->pts_cdev != NULL)
556 sb->st_ino = sb->st_rdev = dev2udev(psc->pts_cdev);
558 #endif /* PTS_EXTERNAL */
559 sb->st_ino = sb->st_rdev = tty_udev(tp);
561 sb->st_atim = dev->si_atime;
562 sb->st_ctim = dev->si_ctime;
563 sb->st_mtim = dev->si_mtime;
564 sb->st_uid = dev->si_uid;
565 sb->st_gid = dev->si_gid;
566 sb->st_mode = dev->si_mode | S_IFCHR;
572 ptsdev_close(struct file *fp, struct thread *td)
574 struct tty *tp = fp->f_data;
576 /* Deallocate TTY device. */
581 * Open of /dev/ptmx or /dev/ptyXX changes the type of file
582 * from DTYPE_VNODE to DTYPE_PTS. vn_open() increases vnode
583 * use count, we need to decrement it, and possibly do other
586 if (fp->f_vnode != NULL)
587 return (vnops.fo_close(fp, td));
593 ptsdev_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp)
597 kif->kf_type = KF_TYPE_PTS;
599 kif->kf_un.kf_pts.kf_pts_dev = tty_udev(tp);
600 kif->kf_un.kf_pts.kf_pts_dev_freebsd11 =
601 kif->kf_un.kf_pts.kf_pts_dev; /* truncate */
602 strlcpy(kif->kf_path, tty_devname(tp), sizeof(kif->kf_path));
606 static struct fileops ptsdev_ops = {
607 .fo_read = ptsdev_read,
608 .fo_write = ptsdev_write,
609 .fo_truncate = invfo_truncate,
610 .fo_ioctl = ptsdev_ioctl,
611 .fo_poll = ptsdev_poll,
612 .fo_kqfilter = ptsdev_kqfilter,
613 .fo_stat = ptsdev_stat,
614 .fo_close = ptsdev_close,
615 .fo_chmod = invfo_chmod,
616 .fo_chown = invfo_chown,
617 .fo_sendfile = invfo_sendfile,
618 .fo_fill_kinfo = ptsdev_fill_kinfo,
619 .fo_flags = DFLAG_PASSABLE,
627 ptsdrv_outwakeup(struct tty *tp)
629 struct pts_softc *psc = tty_softc(tp);
631 cv_broadcast(&psc->pts_outwait);
632 selwakeup(&psc->pts_outpoll);
633 KNOTE_LOCKED(&psc->pts_outpoll.si_note, 0);
637 ptsdrv_inwakeup(struct tty *tp)
639 struct pts_softc *psc = tty_softc(tp);
641 cv_broadcast(&psc->pts_inwait);
642 selwakeup(&psc->pts_inpoll);
643 KNOTE_LOCKED(&psc->pts_inpoll.si_note, 0);
647 ptsdrv_open(struct tty *tp)
649 struct pts_softc *psc = tty_softc(tp);
651 psc->pts_flags &= ~PTS_FINISHED;
657 ptsdrv_close(struct tty *tp)
659 struct pts_softc *psc = tty_softc(tp);
661 /* Wake up any blocked readers/writers. */
662 psc->pts_flags |= PTS_FINISHED;
663 ptsdrv_outwakeup(tp);
668 ptsdrv_pktnotify(struct tty *tp, char event)
670 struct pts_softc *psc = tty_softc(tp);
673 * Clear conflicting flags.
678 psc->pts_pkt &= ~TIOCPKT_START;
681 psc->pts_pkt &= ~TIOCPKT_STOP;
684 psc->pts_pkt &= ~TIOCPKT_DOSTOP;
687 psc->pts_pkt &= ~TIOCPKT_NOSTOP;
691 psc->pts_pkt |= event;
692 ptsdrv_outwakeup(tp);
696 ptsdrv_free(void *softc)
698 struct pts_softc *psc = softc;
700 /* Make device number available again. */
701 if (psc->pts_unit >= 0)
702 free_unr(pts_pool, psc->pts_unit);
704 chgptscnt(psc->pts_cred->cr_ruidinfo, -1, 0);
705 racct_sub_cred(psc->pts_cred, RACCT_NPTS, 1);
706 crfree(psc->pts_cred);
708 seldrain(&psc->pts_inpoll);
709 seldrain(&psc->pts_outpoll);
710 knlist_destroy(&psc->pts_inpoll.si_note);
711 knlist_destroy(&psc->pts_outpoll.si_note);
714 /* Destroy master device as well. */
715 if (psc->pts_cdev != NULL)
716 destroy_dev_sched(psc->pts_cdev);
717 #endif /* PTS_EXTERNAL */
722 static struct ttydevsw pts_class = {
723 .tsw_flags = TF_NOPREFIX,
724 .tsw_outwakeup = ptsdrv_outwakeup,
725 .tsw_inwakeup = ptsdrv_inwakeup,
726 .tsw_open = ptsdrv_open,
727 .tsw_close = ptsdrv_close,
728 .tsw_pktnotify = ptsdrv_pktnotify,
729 .tsw_free = ptsdrv_free,
734 #endif /* !PTS_EXTERNAL */
736 pts_alloc(int fflags, struct thread *td, struct file *fp)
740 struct pts_softc *psc;
741 struct proc *p = td->td_proc;
742 struct ucred *cred = td->td_ucred;
744 /* Resource limiting. */
746 error = racct_add(p, RACCT_NPTS, 1);
751 ok = chgptscnt(cred->cr_ruidinfo, 1, lim_cur(td, RLIMIT_NPTS));
753 racct_sub(p, RACCT_NPTS, 1);
759 /* Try to allocate a new pts unit number. */
760 unit = alloc_unr(pts_pool);
762 racct_sub(p, RACCT_NPTS, 1);
763 chgptscnt(cred->cr_ruidinfo, -1, 0);
767 /* Allocate TTY and softc. */
768 psc = malloc(sizeof(struct pts_softc), M_PTS, M_WAITOK|M_ZERO);
769 cv_init(&psc->pts_inwait, "ptsin");
770 cv_init(&psc->pts_outwait, "ptsout");
772 psc->pts_unit = unit;
773 psc->pts_cred = crhold(cred);
775 tp = tty_alloc(&pts_class, psc);
776 knlist_init_mtx(&psc->pts_inpoll.si_note, tp->t_mtx);
777 knlist_init_mtx(&psc->pts_outpoll.si_note, tp->t_mtx);
779 /* Expose the slave device as well. */
780 tty_makedev(tp, td->td_ucred, "pts/%u", psc->pts_unit);
782 finit(fp, fflags, DTYPE_PTS, tp, &ptsdev_ops);
789 pts_alloc_external(int fflags, struct thread *td, struct file *fp,
790 struct cdev *dev, const char *name)
794 struct pts_softc *psc;
795 struct proc *p = td->td_proc;
796 struct ucred *cred = td->td_ucred;
798 /* Resource limiting. */
800 error = racct_add(p, RACCT_NPTS, 1);
805 ok = chgptscnt(cred->cr_ruidinfo, 1, lim_cur(td, RLIMIT_NPTS));
807 racct_sub(p, RACCT_NPTS, 1);
813 /* Allocate TTY and softc. */
814 psc = malloc(sizeof(struct pts_softc), M_PTS, M_WAITOK|M_ZERO);
815 cv_init(&psc->pts_inwait, "ptsin");
816 cv_init(&psc->pts_outwait, "ptsout");
820 psc->pts_cred = crhold(cred);
822 tp = tty_alloc(&pts_class, psc);
823 knlist_init_mtx(&psc->pts_inpoll.si_note, tp->t_mtx);
824 knlist_init_mtx(&psc->pts_outpoll.si_note, tp->t_mtx);
826 /* Expose the slave device as well. */
827 tty_makedev(tp, td->td_ucred, "%s", name);
829 finit(fp, fflags, DTYPE_PTS, tp, &ptsdev_ops);
833 #endif /* PTS_EXTERNAL */
836 sys_posix_openpt(struct thread *td, struct posix_openpt_args *uap)
842 * POSIX states it's unspecified when other flags are passed. We
845 if (uap->flags & ~(O_RDWR|O_NOCTTY|O_CLOEXEC))
848 error = falloc(td, &fp, &fd, uap->flags);
852 /* Allocate the actual pseudo-TTY. */
853 error = pts_alloc(FFLAGS(uap->flags & O_ACCMODE), td, fp);
860 /* Pass it back to userspace. */
861 td->td_retval[0] = fd;
868 pts_init(void *unused)
871 pts_pool = new_unrhdr(0, INT_MAX, NULL);
874 SYSINIT(pts, SI_SUB_DRIVERS, SI_ORDER_MIDDLE, pts_init, NULL);