2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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 __FBSDID("$FreeBSD$");
35 /* Add compatibility bits for FreeBSD. */
37 /* Add pty(4) compat bits. */
39 /* Add bits to make Linux binaries work. */
42 #include <sys/param.h>
44 #include <sys/condvar.h>
46 #include <sys/fcntl.h>
48 #include <sys/filedesc.h>
49 #include <sys/filio.h>
50 #include <sys/kernel.h>
51 #include <sys/limits.h>
52 #include <sys/malloc.h>
53 #include <sys/mutex.h>
56 #include <sys/racct.h>
57 #include <sys/resourcevar.h>
58 #include <sys/serial.h>
60 #include <sys/syscall.h>
61 #include <sys/syscallsubr.h>
62 #include <sys/sysctl.h>
63 #include <sys/sysent.h>
64 #include <sys/sysproto.h>
65 #include <sys/systm.h>
67 #include <sys/ttycom.h>
71 #include <machine/stdarg.h>
74 * Our utmp(5) format is limited to 8-byte TTY line names. This means
75 * we can at most allocate 1000 pseudo-terminals ("pts/999"). Allow
76 * users to increase this number, assuming they have manually increased
79 static struct unrhdr *pts_pool;
81 static MALLOC_DEFINE(M_PTS, "pts", "pseudo tty device");
87 * (t) locked by tty_lock()
88 * (c) const until freeing
91 int pts_unit; /* (c) Device unit number. */
92 unsigned int pts_flags; /* (t) Device flags. */
93 #define PTS_PKT 0x1 /* Packet mode. */
94 #define PTS_FINISHED 0x2 /* Return errors on read()/write(). */
95 char pts_pkt; /* (t) Unread packet mode data. */
97 struct cv pts_inwait; /* (t) Blocking write() on master. */
98 struct selinfo pts_inpoll; /* (t) Select queue for write(). */
99 struct cv pts_outwait; /* (t) Blocking read() on master. */
100 struct selinfo pts_outpoll; /* (t) Select queue for read(). */
103 struct cdev *pts_cdev; /* (c) Master device node. */
104 #endif /* PTS_EXTERNAL */
106 struct ucred *pts_cred; /* (c) Resource limit. */
110 * Controller-side file operations.
114 ptsdev_read(struct file *fp, struct uio *uio, struct ucred *active_cred,
115 int flags, struct thread *td)
117 struct tty *tp = fp->f_data;
118 struct pts_softc *psc = tty_softc(tp);
122 if (uio->uio_resid == 0)
129 * Implement packet mode. When packet mode is turned on,
130 * the first byte contains a bitmask of events that
131 * occurred (start, stop, flush, window size, etc).
133 if (psc->pts_flags & PTS_PKT && psc->pts_pkt) {
138 error = ureadc(pkt, uio);
143 * Transmit regular data.
145 * XXX: We shouldn't use ttydisc_getc_poll()! Even
146 * though in this implementation, there is likely going
147 * to be data, we should just call ttydisc_getc_uio()
148 * and use its return value to sleep.
150 if (ttydisc_getc_poll(tp)) {
151 if (psc->pts_flags & PTS_PKT) {
153 * XXX: Small race. Fortunately PTY
154 * consumers aren't multithreaded.
158 error = ureadc(TIOCPKT_DATA, uio);
164 error = ttydisc_getc_uio(tp, uio);
168 /* Maybe the device isn't used anyway. */
169 if (psc->pts_flags & PTS_FINISHED)
172 /* Wait for more data. */
173 if (fp->f_flag & O_NONBLOCK) {
177 error = cv_wait_sig(&psc->pts_outwait, tp->t_mtx);
188 ptsdev_write(struct file *fp, struct uio *uio, struct ucred *active_cred,
189 int flags, struct thread *td)
191 struct tty *tp = fp->f_data;
192 struct pts_softc *psc = tty_softc(tp);
193 char ib[256], *ibstart;
194 size_t iblen, rintlen;
197 if (uio->uio_resid == 0)
202 iblen = MIN(uio->uio_resid, sizeof ib);
203 error = uiomove(ib, iblen, uio);
212 * When possible, avoid the slow path. rint_bypass()
213 * copies all input to the input queue at once.
217 rintlen = ttydisc_rint_simple(tp, ibstart, iblen);
221 /* All data written. */
225 /* Maybe the device isn't used anyway. */
226 if (psc->pts_flags & PTS_FINISHED) {
231 /* Wait for more data. */
232 if (fp->f_flag & O_NONBLOCK) {
237 /* Wake up users on the slave side. */
238 ttydisc_rint_done(tp);
239 error = cv_wait_sig(&psc->pts_inwait, tp->t_mtx);
244 if (uio->uio_resid == 0)
249 done: ttydisc_rint_done(tp);
253 * Don't account for the part of the buffer that we couldn't
256 uio->uio_resid += iblen;
261 ptsdev_ioctl(struct file *fp, u_long cmd, void *data,
262 struct ucred *active_cred, struct thread *td)
264 struct tty *tp = fp->f_data;
265 struct pts_softc *psc = tty_softc(tp);
270 *(int *)data = D_TTY;
273 /* This device supports non-blocking operation. */
277 if (psc->pts_flags & PTS_FINISHED) {
278 /* Force read() to be called. */
281 *(int *)data = ttydisc_getc_poll(tp);
286 #ifdef COMPAT_FREEBSD32
290 struct fiodgname_arg *fgn;
294 /* Reverse device name lookups, for ptsname() and ttyname(). */
300 return (copyout(p, fiodgname_buf_get_ptr(fgn, cmd), i));
304 * We need to implement TIOCGPGRP and TIOCGSID here again. When
305 * called on the pseudo-terminal master, it should not check if
306 * the terminal is the foreground terminal of the calling
309 * TIOCGETA is also implemented here. Various Linux PTY routines
310 * often call isatty(), which is implemented by tcgetattr().
314 /* Obtain terminal flags through tcgetattr(). */
316 *(struct termios*)data = tp->t_termios;
319 #endif /* PTS_LINUX */
323 * We must make sure we turn tcsetattr() calls of TCSAFLUSH and
324 * TCSADRAIN into something different. If an application would
325 * call TCSAFLUSH or TCSADRAIN on the master descriptor, it may
326 * deadlock waiting for all data to be read.
330 #if defined(PTS_COMPAT) || defined(PTS_LINUX)
333 * Get the device unit number.
335 if (psc->pts_unit < 0)
337 *(unsigned int *)data = psc->pts_unit;
339 #endif /* PTS_COMPAT || PTS_LINUX */
341 /* Get the foreground process group ID. */
343 if (tp->t_pgrp != NULL)
344 *(int *)data = tp->t_pgrp->pg_id;
346 *(int *)data = NO_PID;
350 /* Get the session leader process ID. */
352 if (tp->t_session == NULL)
355 *(int *)data = tp->t_session->s_sid;
359 /* Yes, we are a pseudo-terminal master. */
362 /* Signal the foreground process group. */
364 if (sig < 1 || sig >= NSIG)
368 tty_signal_pgrp(tp, sig);
372 /* Enable/disable packet mode. */
375 psc->pts_flags |= PTS_PKT;
377 psc->pts_flags &= ~PTS_PKT;
382 /* Just redirect this ioctl to the slave device. */
384 error = tty_ioctl(tp, cmd, data, fp->f_flag, td);
386 if (error == ENOIOCTL)
393 ptsdev_poll(struct file *fp, int events, struct ucred *active_cred,
396 struct tty *tp = fp->f_data;
397 struct pts_softc *psc = tty_softc(tp);
402 if (psc->pts_flags & PTS_FINISHED) {
403 /* Slave device is not opened. */
405 return ((events & (POLLIN|POLLRDNORM)) | POLLHUP);
408 if (events & (POLLIN|POLLRDNORM)) {
409 /* See if we can getc something. */
410 if (ttydisc_getc_poll(tp) ||
411 (psc->pts_flags & PTS_PKT && psc->pts_pkt))
412 revents |= events & (POLLIN|POLLRDNORM);
414 if (events & (POLLOUT|POLLWRNORM)) {
415 /* See if we can rint something. */
416 if (ttydisc_rint_poll(tp))
417 revents |= events & (POLLOUT|POLLWRNORM);
421 * No need to check for POLLHUP here. This device cannot be used
422 * as a callout device, which means we always have a carrier,
423 * because the master is.
428 * This code might look misleading, but the naming of
429 * poll events on this side is the opposite of the slave
432 if (events & (POLLIN|POLLRDNORM))
433 selrecord(td, &psc->pts_outpoll);
434 if (events & (POLLOUT|POLLWRNORM))
435 selrecord(td, &psc->pts_inpoll);
448 pts_kqops_read_detach(struct knote *kn)
450 struct file *fp = kn->kn_fp;
451 struct tty *tp = fp->f_data;
452 struct pts_softc *psc = tty_softc(tp);
454 knlist_remove(&psc->pts_outpoll.si_note, kn, 0);
458 pts_kqops_read_event(struct knote *kn, long hint)
460 struct file *fp = kn->kn_fp;
461 struct tty *tp = fp->f_data;
462 struct pts_softc *psc = tty_softc(tp);
464 if (psc->pts_flags & PTS_FINISHED) {
465 kn->kn_flags |= EV_EOF;
468 kn->kn_data = ttydisc_getc_poll(tp);
469 return (kn->kn_data > 0);
474 pts_kqops_write_detach(struct knote *kn)
476 struct file *fp = kn->kn_fp;
477 struct tty *tp = fp->f_data;
478 struct pts_softc *psc = tty_softc(tp);
480 knlist_remove(&psc->pts_inpoll.si_note, kn, 0);
484 pts_kqops_write_event(struct knote *kn, long hint)
486 struct file *fp = kn->kn_fp;
487 struct tty *tp = fp->f_data;
488 struct pts_softc *psc = tty_softc(tp);
490 if (psc->pts_flags & PTS_FINISHED) {
491 kn->kn_flags |= EV_EOF;
494 kn->kn_data = ttydisc_rint_poll(tp);
495 return (kn->kn_data > 0);
499 static struct filterops pts_kqops_read = {
501 .f_detach = pts_kqops_read_detach,
502 .f_event = pts_kqops_read_event,
504 static struct filterops pts_kqops_write = {
506 .f_detach = pts_kqops_write_detach,
507 .f_event = pts_kqops_write_event,
511 ptsdev_kqfilter(struct file *fp, struct knote *kn)
513 struct tty *tp = fp->f_data;
514 struct pts_softc *psc = tty_softc(tp);
519 switch (kn->kn_filter) {
521 kn->kn_fop = &pts_kqops_read;
522 knlist_add(&psc->pts_outpoll.si_note, kn, 1);
525 kn->kn_fop = &pts_kqops_write;
526 knlist_add(&psc->pts_inpoll.si_note, kn, 1);
538 ptsdev_stat(struct file *fp, struct stat *sb, struct ucred *active_cred,
541 struct tty *tp = fp->f_data;
543 struct pts_softc *psc = tty_softc(tp);
544 #endif /* PTS_EXTERNAL */
545 struct cdev *dev = tp->t_dev;
548 * According to POSIX, we must implement an fstat(). This also
549 * makes this implementation compatible with Linux binaries,
550 * because Linux calls fstat() on the pseudo-terminal master to
553 * XXX: POSIX also mentions we must fill in st_dev, but how?
556 bzero(sb, sizeof *sb);
558 if (psc->pts_cdev != NULL)
559 sb->st_ino = sb->st_rdev = dev2udev(psc->pts_cdev);
561 #endif /* PTS_EXTERNAL */
562 sb->st_ino = sb->st_rdev = tty_udev(tp);
564 sb->st_atim = dev->si_atime;
565 sb->st_ctim = dev->si_ctime;
566 sb->st_mtim = dev->si_mtime;
567 sb->st_uid = dev->si_uid;
568 sb->st_gid = dev->si_gid;
569 sb->st_mode = dev->si_mode | S_IFCHR;
575 ptsdev_close(struct file *fp, struct thread *td)
577 struct tty *tp = fp->f_data;
579 /* Deallocate TTY device. */
584 * Open of /dev/ptmx or /dev/ptyXX changes the type of file
585 * from DTYPE_VNODE to DTYPE_PTS. vn_open() increases vnode
586 * use count, we need to decrement it, and possibly do other
589 if (fp->f_vnode != NULL)
590 return (vnops.fo_close(fp, td));
596 ptsdev_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp)
600 kif->kf_type = KF_TYPE_PTS;
602 kif->kf_un.kf_pts.kf_pts_dev = tty_udev(tp);
603 kif->kf_un.kf_pts.kf_pts_dev_freebsd11 =
604 kif->kf_un.kf_pts.kf_pts_dev; /* truncate */
605 strlcpy(kif->kf_path, tty_devname(tp), sizeof(kif->kf_path));
609 static struct fileops ptsdev_ops = {
610 .fo_read = ptsdev_read,
611 .fo_write = ptsdev_write,
612 .fo_truncate = invfo_truncate,
613 .fo_ioctl = ptsdev_ioctl,
614 .fo_poll = ptsdev_poll,
615 .fo_kqfilter = ptsdev_kqfilter,
616 .fo_stat = ptsdev_stat,
617 .fo_close = ptsdev_close,
618 .fo_chmod = invfo_chmod,
619 .fo_chown = invfo_chown,
620 .fo_sendfile = invfo_sendfile,
621 .fo_fill_kinfo = ptsdev_fill_kinfo,
622 .fo_flags = DFLAG_PASSABLE,
630 ptsdrv_outwakeup(struct tty *tp)
632 struct pts_softc *psc = tty_softc(tp);
634 cv_broadcast(&psc->pts_outwait);
635 selwakeup(&psc->pts_outpoll);
636 KNOTE_LOCKED(&psc->pts_outpoll.si_note, 0);
640 ptsdrv_inwakeup(struct tty *tp)
642 struct pts_softc *psc = tty_softc(tp);
644 cv_broadcast(&psc->pts_inwait);
645 selwakeup(&psc->pts_inpoll);
646 KNOTE_LOCKED(&psc->pts_inpoll.si_note, 0);
650 ptsdrv_open(struct tty *tp)
652 struct pts_softc *psc = tty_softc(tp);
654 psc->pts_flags &= ~PTS_FINISHED;
660 ptsdrv_close(struct tty *tp)
662 struct pts_softc *psc = tty_softc(tp);
664 /* Wake up any blocked readers/writers. */
665 psc->pts_flags |= PTS_FINISHED;
666 ptsdrv_outwakeup(tp);
671 ptsdrv_pktnotify(struct tty *tp, char event)
673 struct pts_softc *psc = tty_softc(tp);
676 * Clear conflicting flags.
681 psc->pts_pkt &= ~TIOCPKT_START;
684 psc->pts_pkt &= ~TIOCPKT_STOP;
687 psc->pts_pkt &= ~TIOCPKT_DOSTOP;
690 psc->pts_pkt &= ~TIOCPKT_NOSTOP;
694 psc->pts_pkt |= event;
695 ptsdrv_outwakeup(tp);
699 ptsdrv_free(void *softc)
701 struct pts_softc *psc = softc;
703 /* Make device number available again. */
704 if (psc->pts_unit >= 0)
705 free_unr(pts_pool, psc->pts_unit);
707 chgptscnt(psc->pts_cred->cr_ruidinfo, -1, 0);
708 racct_sub_cred(psc->pts_cred, RACCT_NPTS, 1);
709 crfree(psc->pts_cred);
711 seldrain(&psc->pts_inpoll);
712 seldrain(&psc->pts_outpoll);
713 knlist_destroy(&psc->pts_inpoll.si_note);
714 knlist_destroy(&psc->pts_outpoll.si_note);
717 /* Destroy master device as well. */
718 if (psc->pts_cdev != NULL)
719 destroy_dev_sched(psc->pts_cdev);
720 #endif /* PTS_EXTERNAL */
725 static struct ttydevsw pts_class = {
726 .tsw_flags = TF_NOPREFIX,
727 .tsw_outwakeup = ptsdrv_outwakeup,
728 .tsw_inwakeup = ptsdrv_inwakeup,
729 .tsw_open = ptsdrv_open,
730 .tsw_close = ptsdrv_close,
731 .tsw_pktnotify = ptsdrv_pktnotify,
732 .tsw_free = ptsdrv_free,
737 #endif /* !PTS_EXTERNAL */
739 pts_alloc(int fflags, struct thread *td, struct file *fp)
743 struct pts_softc *psc;
744 struct proc *p = td->td_proc;
745 struct ucred *cred = td->td_ucred;
747 /* Resource limiting. */
749 error = racct_add(p, RACCT_NPTS, 1);
754 ok = chgptscnt(cred->cr_ruidinfo, 1, lim_cur(td, RLIMIT_NPTS));
756 racct_sub(p, RACCT_NPTS, 1);
762 /* Try to allocate a new pts unit number. */
763 unit = alloc_unr(pts_pool);
765 racct_sub(p, RACCT_NPTS, 1);
766 chgptscnt(cred->cr_ruidinfo, -1, 0);
770 /* Allocate TTY and softc. */
771 psc = malloc(sizeof(struct pts_softc), M_PTS, M_WAITOK|M_ZERO);
772 cv_init(&psc->pts_inwait, "ptsin");
773 cv_init(&psc->pts_outwait, "ptsout");
775 psc->pts_unit = unit;
776 psc->pts_cred = crhold(cred);
778 tp = tty_alloc(&pts_class, psc);
779 knlist_init_mtx(&psc->pts_inpoll.si_note, tp->t_mtx);
780 knlist_init_mtx(&psc->pts_outpoll.si_note, tp->t_mtx);
782 /* Expose the slave device as well. */
783 tty_makedev(tp, td->td_ucred, "pts/%u", psc->pts_unit);
785 finit(fp, fflags, DTYPE_PTS, tp, &ptsdev_ops);
792 pts_alloc_external(int fflags, struct thread *td, struct file *fp,
793 struct cdev *dev, const char *name)
797 struct pts_softc *psc;
798 struct proc *p = td->td_proc;
799 struct ucred *cred = td->td_ucred;
801 /* Resource limiting. */
803 error = racct_add(p, RACCT_NPTS, 1);
808 ok = chgptscnt(cred->cr_ruidinfo, 1, lim_cur(td, RLIMIT_NPTS));
810 racct_sub(p, RACCT_NPTS, 1);
816 /* Allocate TTY and softc. */
817 psc = malloc(sizeof(struct pts_softc), M_PTS, M_WAITOK|M_ZERO);
818 cv_init(&psc->pts_inwait, "ptsin");
819 cv_init(&psc->pts_outwait, "ptsout");
823 psc->pts_cred = crhold(cred);
825 tp = tty_alloc(&pts_class, psc);
826 knlist_init_mtx(&psc->pts_inpoll.si_note, tp->t_mtx);
827 knlist_init_mtx(&psc->pts_outpoll.si_note, tp->t_mtx);
829 /* Expose the slave device as well. */
830 tty_makedev(tp, td->td_ucred, "%s", name);
832 finit(fp, fflags, DTYPE_PTS, tp, &ptsdev_ops);
836 #endif /* PTS_EXTERNAL */
839 sys_posix_openpt(struct thread *td, struct posix_openpt_args *uap)
845 * POSIX states it's unspecified when other flags are passed. We
848 if (uap->flags & ~(O_RDWR|O_NOCTTY|O_CLOEXEC))
851 error = falloc(td, &fp, &fd, uap->flags);
855 /* Allocate the actual pseudo-TTY. */
856 error = pts_alloc(FFLAGS(uap->flags & O_ACCMODE), td, fp);
863 /* Pass it back to userspace. */
864 td->td_retval[0] = fd;
871 pts_init(void *unused)
874 pts_pool = new_unrhdr(0, INT_MAX, NULL);
877 SYSINIT(pts, SI_SUB_DRIVERS, SI_ORDER_MIDDLE, pts_init, NULL);