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>
55 #include <sys/racct.h>
56 #include <sys/resourcevar.h>
57 #include <sys/serial.h>
59 #include <sys/syscall.h>
60 #include <sys/syscallsubr.h>
61 #include <sys/sysctl.h>
62 #include <sys/sysent.h>
63 #include <sys/sysproto.h>
64 #include <sys/systm.h>
66 #include <sys/ttycom.h>
69 #include <machine/stdarg.h>
72 * Our utmp(5) format is limited to 8-byte TTY line names. This means
73 * we can at most allocate 1000 pseudo-terminals ("pts/999"). Allow
74 * users to increase this number, assuming they have manually increased
77 static struct unrhdr *pts_pool;
79 static MALLOC_DEFINE(M_PTS, "pts", "pseudo tty device");
85 * (t) locked by tty_lock()
86 * (c) const until freeing
89 int pts_unit; /* (c) Device unit number. */
90 unsigned int pts_flags; /* (t) Device flags. */
91 #define PTS_PKT 0x1 /* Packet mode. */
92 #define PTS_FINISHED 0x2 /* Return errors on read()/write(). */
93 char pts_pkt; /* (t) Unread packet mode data. */
95 struct cv pts_inwait; /* (t) Blocking write() on master. */
96 struct selinfo pts_inpoll; /* (t) Select queue for write(). */
97 struct cv pts_outwait; /* (t) Blocking read() on master. */
98 struct selinfo pts_outpoll; /* (t) Select queue for read(). */
101 struct cdev *pts_cdev; /* (c) Master device node. */
102 #endif /* PTS_EXTERNAL */
104 struct ucred *pts_cred; /* (c) Resource limit. */
108 * Controller-side file operations.
112 ptsdev_read(struct file *fp, struct uio *uio, struct ucred *active_cred,
113 int flags, struct thread *td)
115 struct tty *tp = fp->f_data;
116 struct pts_softc *psc = tty_softc(tp);
120 if (uio->uio_resid == 0)
127 * Implement packet mode. When packet mode is turned on,
128 * the first byte contains a bitmask of events that
129 * occurred (start, stop, flush, window size, etc).
131 if (psc->pts_flags & PTS_PKT && psc->pts_pkt) {
136 error = ureadc(pkt, uio);
141 * Transmit regular data.
143 * XXX: We shouldn't use ttydisc_getc_poll()! Even
144 * though in this implementation, there is likely going
145 * to be data, we should just call ttydisc_getc_uio()
146 * and use its return value to sleep.
148 if (ttydisc_getc_poll(tp)) {
149 if (psc->pts_flags & PTS_PKT) {
151 * XXX: Small race. Fortunately PTY
152 * consumers aren't multithreaded.
156 error = ureadc(TIOCPKT_DATA, uio);
162 error = ttydisc_getc_uio(tp, uio);
166 /* Maybe the device isn't used anyway. */
167 if (psc->pts_flags & PTS_FINISHED)
170 /* Wait for more data. */
171 if (fp->f_flag & O_NONBLOCK) {
175 error = cv_wait_sig(&psc->pts_outwait, tp->t_mtx);
186 ptsdev_write(struct file *fp, struct uio *uio, struct ucred *active_cred,
187 int flags, struct thread *td)
189 struct tty *tp = fp->f_data;
190 struct pts_softc *psc = tty_softc(tp);
191 char ib[256], *ibstart;
192 size_t iblen, rintlen;
195 if (uio->uio_resid == 0)
200 iblen = MIN(uio->uio_resid, sizeof ib);
201 error = uiomove(ib, iblen, uio);
210 * When possible, avoid the slow path. rint_bypass()
211 * copies all input to the input queue at once.
215 rintlen = ttydisc_rint_simple(tp, ibstart, iblen);
219 /* All data written. */
223 /* Maybe the device isn't used anyway. */
224 if (psc->pts_flags & PTS_FINISHED) {
229 /* Wait for more data. */
230 if (fp->f_flag & O_NONBLOCK) {
235 /* Wake up users on the slave side. */
236 ttydisc_rint_done(tp);
237 error = cv_wait_sig(&psc->pts_inwait, tp->t_mtx);
242 if (uio->uio_resid == 0)
247 done: ttydisc_rint_done(tp);
251 * Don't account for the part of the buffer that we couldn't
254 uio->uio_resid += iblen;
259 ptsdev_ioctl(struct file *fp, u_long cmd, void *data,
260 struct ucred *active_cred, struct thread *td)
262 struct tty *tp = fp->f_data;
263 struct pts_softc *psc = tty_softc(tp);
268 *(int *)data = D_TTY;
271 /* This device supports non-blocking operation. */
275 if (psc->pts_flags & PTS_FINISHED) {
276 /* Force read() to be called. */
279 *(int *)data = ttydisc_getc_poll(tp);
284 struct fiodgname_arg *fgn;
288 /* Reverse device name lookups, for ptsname() and ttyname(). */
294 return copyout(p, fgn->buf, i);
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
303 * TIOCGETA is also implemented here. Various Linux PTY routines
304 * often call isatty(), which is implemented by tcgetattr().
308 /* Obtain terminal flags through tcgetattr(). */
310 *(struct termios*)data = tp->t_termios;
313 #endif /* PTS_LINUX */
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.
324 #if defined(PTS_COMPAT) || defined(PTS_LINUX)
327 * Get the device unit number.
329 if (psc->pts_unit < 0)
331 *(unsigned int *)data = psc->pts_unit;
333 #endif /* PTS_COMPAT || PTS_LINUX */
335 /* Get the foreground process group ID. */
337 if (tp->t_pgrp != NULL)
338 *(int *)data = tp->t_pgrp->pg_id;
340 *(int *)data = NO_PID;
344 /* Get the session leader process ID. */
346 if (tp->t_session == NULL)
349 *(int *)data = tp->t_session->s_sid;
353 /* Yes, we are a pseudo-terminal master. */
356 /* Signal the foreground process group. */
358 if (sig < 1 || sig >= NSIG)
362 tty_signal_pgrp(tp, sig);
366 /* Enable/disable packet mode. */
369 psc->pts_flags |= PTS_PKT;
371 psc->pts_flags &= ~PTS_PKT;
376 /* Just redirect this ioctl to the slave device. */
378 error = tty_ioctl(tp, cmd, data, fp->f_flag, td);
380 if (error == ENOIOCTL)
387 ptsdev_poll(struct file *fp, int events, struct ucred *active_cred,
390 struct tty *tp = fp->f_data;
391 struct pts_softc *psc = tty_softc(tp);
396 if (psc->pts_flags & PTS_FINISHED) {
397 /* Slave device is not opened. */
399 return ((events & (POLLIN|POLLRDNORM)) | POLLHUP);
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);
408 if (events & (POLLOUT|POLLWRNORM)) {
409 /* See if we can rint something. */
410 if (ttydisc_rint_poll(tp))
411 revents |= events & (POLLOUT|POLLWRNORM);
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.
422 * This code might look misleading, but the naming of
423 * poll events on this side is the opposite of the slave
426 if (events & (POLLIN|POLLRDNORM))
427 selrecord(td, &psc->pts_outpoll);
428 if (events & (POLLOUT|POLLWRNORM))
429 selrecord(td, &psc->pts_inpoll);
442 pts_kqops_read_detach(struct knote *kn)
444 struct file *fp = kn->kn_fp;
445 struct tty *tp = fp->f_data;
446 struct pts_softc *psc = tty_softc(tp);
448 knlist_remove(&psc->pts_outpoll.si_note, kn, 0);
452 pts_kqops_read_event(struct knote *kn, long hint)
454 struct file *fp = kn->kn_fp;
455 struct tty *tp = fp->f_data;
456 struct pts_softc *psc = tty_softc(tp);
458 if (psc->pts_flags & PTS_FINISHED) {
459 kn->kn_flags |= EV_EOF;
462 kn->kn_data = ttydisc_getc_poll(tp);
463 return (kn->kn_data > 0);
468 pts_kqops_write_detach(struct knote *kn)
470 struct file *fp = kn->kn_fp;
471 struct tty *tp = fp->f_data;
472 struct pts_softc *psc = tty_softc(tp);
474 knlist_remove(&psc->pts_inpoll.si_note, kn, 0);
478 pts_kqops_write_event(struct knote *kn, long hint)
480 struct file *fp = kn->kn_fp;
481 struct tty *tp = fp->f_data;
482 struct pts_softc *psc = tty_softc(tp);
484 if (psc->pts_flags & PTS_FINISHED) {
485 kn->kn_flags |= EV_EOF;
488 kn->kn_data = ttydisc_rint_poll(tp);
489 return (kn->kn_data > 0);
493 static struct filterops pts_kqops_read = {
495 .f_detach = pts_kqops_read_detach,
496 .f_event = pts_kqops_read_event,
498 static struct filterops pts_kqops_write = {
500 .f_detach = pts_kqops_write_detach,
501 .f_event = pts_kqops_write_event,
505 ptsdev_kqfilter(struct file *fp, struct knote *kn)
507 struct tty *tp = fp->f_data;
508 struct pts_softc *psc = tty_softc(tp);
513 switch (kn->kn_filter) {
515 kn->kn_fop = &pts_kqops_read;
516 knlist_add(&psc->pts_outpoll.si_note, kn, 1);
519 kn->kn_fop = &pts_kqops_write;
520 knlist_add(&psc->pts_inpoll.si_note, kn, 1);
532 ptsdev_stat(struct file *fp, struct stat *sb, struct ucred *active_cred,
535 struct tty *tp = fp->f_data;
537 struct pts_softc *psc = tty_softc(tp);
538 #endif /* PTS_EXTERNAL */
539 struct cdev *dev = tp->t_dev;
542 * According to POSIX, we must implement an fstat(). This also
543 * makes this implementation compatible with Linux binaries,
544 * because Linux calls fstat() on the pseudo-terminal master to
547 * XXX: POSIX also mentions we must fill in st_dev, but how?
550 bzero(sb, sizeof *sb);
552 if (psc->pts_cdev != NULL)
553 sb->st_ino = sb->st_rdev = dev2udev(psc->pts_cdev);
555 #endif /* PTS_EXTERNAL */
556 sb->st_ino = sb->st_rdev = tty_udev(tp);
558 sb->st_atim = dev->si_atime;
559 sb->st_ctim = dev->si_ctime;
560 sb->st_mtim = dev->si_mtime;
561 sb->st_uid = dev->si_uid;
562 sb->st_gid = dev->si_gid;
563 sb->st_mode = dev->si_mode | S_IFCHR;
569 ptsdev_close(struct file *fp, struct thread *td)
571 struct tty *tp = fp->f_data;
573 /* Deallocate TTY device. */
578 * Open of /dev/ptmx or /dev/ptyXX changes the type of file
579 * from DTYPE_VNODE to DTYPE_PTS. vn_open() increases vnode
580 * use count, we need to decrement it, and possibly do other
583 if (fp->f_vnode != NULL)
584 return (vnops.fo_close(fp, td));
590 ptsdev_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp)
594 kif->kf_type = KF_TYPE_PTS;
596 kif->kf_un.kf_pts.kf_pts_dev = tty_udev(tp);
597 kif->kf_un.kf_pts.kf_pts_dev_freebsd11 =
598 kif->kf_un.kf_pts.kf_pts_dev; /* truncate */
599 strlcpy(kif->kf_path, tty_devname(tp), sizeof(kif->kf_path));
603 static struct fileops ptsdev_ops = {
604 .fo_read = ptsdev_read,
605 .fo_write = ptsdev_write,
606 .fo_truncate = invfo_truncate,
607 .fo_ioctl = ptsdev_ioctl,
608 .fo_poll = ptsdev_poll,
609 .fo_kqfilter = ptsdev_kqfilter,
610 .fo_stat = ptsdev_stat,
611 .fo_close = ptsdev_close,
612 .fo_chmod = invfo_chmod,
613 .fo_chown = invfo_chown,
614 .fo_sendfile = invfo_sendfile,
615 .fo_fill_kinfo = ptsdev_fill_kinfo,
616 .fo_flags = DFLAG_PASSABLE,
624 ptsdrv_outwakeup(struct tty *tp)
626 struct pts_softc *psc = tty_softc(tp);
628 cv_broadcast(&psc->pts_outwait);
629 selwakeup(&psc->pts_outpoll);
630 KNOTE_LOCKED(&psc->pts_outpoll.si_note, 0);
634 ptsdrv_inwakeup(struct tty *tp)
636 struct pts_softc *psc = tty_softc(tp);
638 cv_broadcast(&psc->pts_inwait);
639 selwakeup(&psc->pts_inpoll);
640 KNOTE_LOCKED(&psc->pts_inpoll.si_note, 0);
644 ptsdrv_open(struct tty *tp)
646 struct pts_softc *psc = tty_softc(tp);
648 psc->pts_flags &= ~PTS_FINISHED;
654 ptsdrv_close(struct tty *tp)
656 struct pts_softc *psc = tty_softc(tp);
658 /* Wake up any blocked readers/writers. */
659 psc->pts_flags |= PTS_FINISHED;
660 ptsdrv_outwakeup(tp);
665 ptsdrv_pktnotify(struct tty *tp, char event)
667 struct pts_softc *psc = tty_softc(tp);
670 * Clear conflicting flags.
675 psc->pts_pkt &= ~TIOCPKT_START;
678 psc->pts_pkt &= ~TIOCPKT_STOP;
681 psc->pts_pkt &= ~TIOCPKT_DOSTOP;
684 psc->pts_pkt &= ~TIOCPKT_NOSTOP;
688 psc->pts_pkt |= event;
689 ptsdrv_outwakeup(tp);
693 ptsdrv_free(void *softc)
695 struct pts_softc *psc = softc;
697 /* Make device number available again. */
698 if (psc->pts_unit >= 0)
699 free_unr(pts_pool, psc->pts_unit);
701 chgptscnt(psc->pts_cred->cr_ruidinfo, -1, 0);
702 racct_sub_cred(psc->pts_cred, RACCT_NPTS, 1);
703 crfree(psc->pts_cred);
705 seldrain(&psc->pts_inpoll);
706 seldrain(&psc->pts_outpoll);
707 knlist_destroy(&psc->pts_inpoll.si_note);
708 knlist_destroy(&psc->pts_outpoll.si_note);
711 /* Destroy master device as well. */
712 if (psc->pts_cdev != NULL)
713 destroy_dev_sched(psc->pts_cdev);
714 #endif /* PTS_EXTERNAL */
719 static struct ttydevsw pts_class = {
720 .tsw_flags = TF_NOPREFIX,
721 .tsw_outwakeup = ptsdrv_outwakeup,
722 .tsw_inwakeup = ptsdrv_inwakeup,
723 .tsw_open = ptsdrv_open,
724 .tsw_close = ptsdrv_close,
725 .tsw_pktnotify = ptsdrv_pktnotify,
726 .tsw_free = ptsdrv_free,
731 #endif /* !PTS_EXTERNAL */
733 pts_alloc(int fflags, struct thread *td, struct file *fp)
737 struct pts_softc *psc;
738 struct proc *p = td->td_proc;
739 struct ucred *cred = td->td_ucred;
741 /* Resource limiting. */
743 error = racct_add(p, RACCT_NPTS, 1);
748 ok = chgptscnt(cred->cr_ruidinfo, 1, lim_cur(td, RLIMIT_NPTS));
750 racct_sub(p, RACCT_NPTS, 1);
756 /* Try to allocate a new pts unit number. */
757 unit = alloc_unr(pts_pool);
759 racct_sub(p, RACCT_NPTS, 1);
760 chgptscnt(cred->cr_ruidinfo, -1, 0);
764 /* Allocate TTY and softc. */
765 psc = malloc(sizeof(struct pts_softc), M_PTS, M_WAITOK|M_ZERO);
766 cv_init(&psc->pts_inwait, "ptsin");
767 cv_init(&psc->pts_outwait, "ptsout");
769 psc->pts_unit = unit;
770 psc->pts_cred = crhold(cred);
772 tp = tty_alloc(&pts_class, psc);
773 knlist_init_mtx(&psc->pts_inpoll.si_note, tp->t_mtx);
774 knlist_init_mtx(&psc->pts_outpoll.si_note, tp->t_mtx);
776 /* Expose the slave device as well. */
777 tty_makedev(tp, td->td_ucred, "pts/%u", psc->pts_unit);
779 finit(fp, fflags, DTYPE_PTS, tp, &ptsdev_ops);
786 pts_alloc_external(int fflags, struct thread *td, struct file *fp,
787 struct cdev *dev, const char *name)
791 struct pts_softc *psc;
792 struct proc *p = td->td_proc;
793 struct ucred *cred = td->td_ucred;
795 /* Resource limiting. */
797 error = racct_add(p, RACCT_NPTS, 1);
802 ok = chgptscnt(cred->cr_ruidinfo, 1, lim_cur(td, RLIMIT_NPTS));
804 racct_sub(p, RACCT_NPTS, 1);
810 /* Allocate TTY and softc. */
811 psc = malloc(sizeof(struct pts_softc), M_PTS, M_WAITOK|M_ZERO);
812 cv_init(&psc->pts_inwait, "ptsin");
813 cv_init(&psc->pts_outwait, "ptsout");
817 psc->pts_cred = crhold(cred);
819 tp = tty_alloc(&pts_class, psc);
820 knlist_init_mtx(&psc->pts_inpoll.si_note, tp->t_mtx);
821 knlist_init_mtx(&psc->pts_outpoll.si_note, tp->t_mtx);
823 /* Expose the slave device as well. */
824 tty_makedev(tp, td->td_ucred, "%s", name);
826 finit(fp, fflags, DTYPE_PTS, tp, &ptsdev_ops);
830 #endif /* PTS_EXTERNAL */
833 sys_posix_openpt(struct thread *td, struct posix_openpt_args *uap)
839 * POSIX states it's unspecified when other flags are passed. We
842 if (uap->flags & ~(O_RDWR|O_NOCTTY|O_CLOEXEC))
845 error = falloc(td, &fp, &fd, uap->flags);
849 /* Allocate the actual pseudo-TTY. */
850 error = pts_alloc(FFLAGS(uap->flags & O_ACCMODE), td, fp);
857 /* Pass it back to userspace. */
858 td->td_retval[0] = fd;
865 pts_init(void *unused)
868 pts_pool = new_unrhdr(0, INT_MAX, NULL);
871 SYSINIT(pts, SI_SUB_DRIVERS, SI_ORDER_MIDDLE, pts_init, NULL);