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/sysproto.h>
64 #include <sys/systm.h>
66 #include <sys/ttycom.h>
70 #include <machine/stdarg.h>
73 * Our utmp(5) format is limited to 8-byte TTY line names. This means
74 * we can at most allocate 1000 pseudo-terminals ("pts/999"). Allow
75 * users to increase this number, assuming they have manually increased
78 static struct unrhdr *pts_pool;
80 static MALLOC_DEFINE(M_PTS, "pts", "pseudo tty device");
86 * (t) locked by tty_lock()
87 * (c) const until freeing
90 int pts_unit; /* (c) Device unit number. */
91 unsigned int pts_flags; /* (t) Device flags. */
92 #define PTS_PKT 0x1 /* Packet mode. */
93 #define PTS_FINISHED 0x2 /* Return errors on read()/write(). */
94 char pts_pkt; /* (t) Unread packet mode data. */
96 struct cv pts_inwait; /* (t) Blocking write() on master. */
97 struct selinfo pts_inpoll; /* (t) Select queue for write(). */
98 struct cv pts_outwait; /* (t) Blocking read() on master. */
99 struct selinfo pts_outpoll; /* (t) Select queue for read(). */
102 struct cdev *pts_cdev; /* (c) Master device node. */
103 #endif /* PTS_EXTERNAL */
105 struct ucred *pts_cred; /* (c) Resource limit. */
109 * Controller-side file operations.
113 ptsdev_read(struct file *fp, struct uio *uio, struct ucred *active_cred,
114 int flags, struct thread *td)
116 struct tty *tp = fp->f_data;
117 struct pts_softc *psc = tty_softc(tp);
121 if (uio->uio_resid == 0)
128 * Implement packet mode. When packet mode is turned on,
129 * the first byte contains a bitmask of events that
130 * occurred (start, stop, flush, window size, etc).
132 if (psc->pts_flags & PTS_PKT && psc->pts_pkt) {
137 error = ureadc(pkt, uio);
142 * Transmit regular data.
144 * XXX: We shouldn't use ttydisc_getc_poll()! Even
145 * though in this implementation, there is likely going
146 * to be data, we should just call ttydisc_getc_uio()
147 * and use its return value to sleep.
149 if (ttydisc_getc_poll(tp)) {
150 if (psc->pts_flags & PTS_PKT) {
152 * XXX: Small race. Fortunately PTY
153 * consumers aren't multithreaded.
157 error = ureadc(TIOCPKT_DATA, uio);
163 error = ttydisc_getc_uio(tp, uio);
167 /* Maybe the device isn't used anyway. */
168 if (psc->pts_flags & PTS_FINISHED)
171 /* Wait for more data. */
172 if (fp->f_flag & O_NONBLOCK) {
176 error = cv_wait_sig(&psc->pts_outwait, tp->t_mtx);
187 ptsdev_write(struct file *fp, struct uio *uio, struct ucred *active_cred,
188 int flags, struct thread *td)
190 struct tty *tp = fp->f_data;
191 struct pts_softc *psc = tty_softc(tp);
192 char ib[256], *ibstart;
193 size_t iblen, rintlen;
196 if (uio->uio_resid == 0)
201 iblen = MIN(uio->uio_resid, sizeof ib);
202 error = uiomove(ib, iblen, uio);
211 * When possible, avoid the slow path. rint_bypass()
212 * copies all input to the input queue at once.
216 rintlen = ttydisc_rint_simple(tp, ibstart, iblen);
220 /* All data written. */
224 /* Maybe the device isn't used anyway. */
225 if (psc->pts_flags & PTS_FINISHED) {
230 /* Wait for more data. */
231 if (fp->f_flag & O_NONBLOCK) {
236 /* Wake up users on the slave side. */
237 ttydisc_rint_done(tp);
238 error = cv_wait_sig(&psc->pts_inwait, tp->t_mtx);
243 if (uio->uio_resid == 0)
248 done: ttydisc_rint_done(tp);
252 * Don't account for the part of the buffer that we couldn't
255 uio->uio_resid += iblen;
260 ptsdev_ioctl(struct file *fp, u_long cmd, void *data,
261 struct ucred *active_cred, struct thread *td)
263 struct tty *tp = fp->f_data;
264 struct pts_softc *psc = tty_softc(tp);
269 *(int *)data = D_TTY;
272 /* This device supports non-blocking operation. */
276 if (psc->pts_flags & PTS_FINISHED) {
277 /* Force read() to be called. */
280 *(int *)data = ttydisc_getc_poll(tp);
285 #ifdef COMPAT_FREEBSD32
289 struct fiodgname_arg *fgn;
293 /* Reverse device name lookups, for ptsname() and ttyname(). */
299 return (copyout(p, fiodgname_buf_get_ptr(fgn, cmd), i));
303 * We need to implement TIOCGPGRP and TIOCGSID here again. When
304 * called on the pseudo-terminal master, it should not check if
305 * the terminal is the foreground terminal of the calling
308 * TIOCGETA is also implemented here. Various Linux PTY routines
309 * often call isatty(), which is implemented by tcgetattr().
313 /* Obtain terminal flags through tcgetattr(). */
315 *(struct termios*)data = tp->t_termios;
318 #endif /* PTS_LINUX */
322 * We must make sure we turn tcsetattr() calls of TCSAFLUSH and
323 * TCSADRAIN into something different. If an application would
324 * call TCSAFLUSH or TCSADRAIN on the master descriptor, it may
325 * deadlock waiting for all data to be read.
329 #if defined(PTS_COMPAT) || defined(PTS_LINUX)
332 * Get the device unit number.
334 if (psc->pts_unit < 0)
336 *(unsigned int *)data = psc->pts_unit;
338 #endif /* PTS_COMPAT || PTS_LINUX */
340 /* Get the foreground process group ID. */
342 if (tp->t_pgrp != NULL)
343 *(int *)data = tp->t_pgrp->pg_id;
345 *(int *)data = NO_PID;
349 /* Get the session leader process ID. */
351 if (tp->t_session == NULL)
354 *(int *)data = tp->t_session->s_sid;
358 /* Yes, we are a pseudo-terminal master. */
361 /* Signal the foreground process group. */
363 if (sig < 1 || sig >= NSIG)
367 tty_signal_pgrp(tp, sig);
371 /* Enable/disable packet mode. */
374 psc->pts_flags |= PTS_PKT;
376 psc->pts_flags &= ~PTS_PKT;
381 /* Just redirect this ioctl to the slave device. */
383 error = tty_ioctl(tp, cmd, data, fp->f_flag, td);
385 if (error == ENOIOCTL)
392 ptsdev_poll(struct file *fp, int events, struct ucred *active_cred,
395 struct tty *tp = fp->f_data;
396 struct pts_softc *psc = tty_softc(tp);
401 if (psc->pts_flags & PTS_FINISHED) {
402 /* Slave device is not opened. */
404 return ((events & (POLLIN|POLLRDNORM)) | POLLHUP);
407 if (events & (POLLIN|POLLRDNORM)) {
408 /* See if we can getc something. */
409 if (ttydisc_getc_poll(tp) ||
410 (psc->pts_flags & PTS_PKT && psc->pts_pkt))
411 revents |= events & (POLLIN|POLLRDNORM);
413 if (events & (POLLOUT|POLLWRNORM)) {
414 /* See if we can rint something. */
415 if (ttydisc_rint_poll(tp))
416 revents |= events & (POLLOUT|POLLWRNORM);
420 * No need to check for POLLHUP here. This device cannot be used
421 * as a callout device, which means we always have a carrier,
422 * because the master is.
427 * This code might look misleading, but the naming of
428 * poll events on this side is the opposite of the slave
431 if (events & (POLLIN|POLLRDNORM))
432 selrecord(td, &psc->pts_outpoll);
433 if (events & (POLLOUT|POLLWRNORM))
434 selrecord(td, &psc->pts_inpoll);
447 pts_kqops_read_detach(struct knote *kn)
449 struct file *fp = kn->kn_fp;
450 struct tty *tp = fp->f_data;
451 struct pts_softc *psc = tty_softc(tp);
453 knlist_remove(&psc->pts_outpoll.si_note, kn, 0);
457 pts_kqops_read_event(struct knote *kn, long hint)
459 struct file *fp = kn->kn_fp;
460 struct tty *tp = fp->f_data;
461 struct pts_softc *psc = tty_softc(tp);
463 if (psc->pts_flags & PTS_FINISHED) {
464 kn->kn_flags |= EV_EOF;
467 kn->kn_data = ttydisc_getc_poll(tp);
468 return (kn->kn_data > 0);
473 pts_kqops_write_detach(struct knote *kn)
475 struct file *fp = kn->kn_fp;
476 struct tty *tp = fp->f_data;
477 struct pts_softc *psc = tty_softc(tp);
479 knlist_remove(&psc->pts_inpoll.si_note, kn, 0);
483 pts_kqops_write_event(struct knote *kn, long hint)
485 struct file *fp = kn->kn_fp;
486 struct tty *tp = fp->f_data;
487 struct pts_softc *psc = tty_softc(tp);
489 if (psc->pts_flags & PTS_FINISHED) {
490 kn->kn_flags |= EV_EOF;
493 kn->kn_data = ttydisc_rint_poll(tp);
494 return (kn->kn_data > 0);
498 static struct filterops pts_kqops_read = {
500 .f_detach = pts_kqops_read_detach,
501 .f_event = pts_kqops_read_event,
503 static struct filterops pts_kqops_write = {
505 .f_detach = pts_kqops_write_detach,
506 .f_event = pts_kqops_write_event,
510 ptsdev_kqfilter(struct file *fp, struct knote *kn)
512 struct tty *tp = fp->f_data;
513 struct pts_softc *psc = tty_softc(tp);
518 switch (kn->kn_filter) {
520 kn->kn_fop = &pts_kqops_read;
521 knlist_add(&psc->pts_outpoll.si_note, kn, 1);
524 kn->kn_fop = &pts_kqops_write;
525 knlist_add(&psc->pts_inpoll.si_note, kn, 1);
537 ptsdev_stat(struct file *fp, struct stat *sb, struct ucred *active_cred,
540 struct tty *tp = fp->f_data;
542 struct pts_softc *psc = tty_softc(tp);
543 #endif /* PTS_EXTERNAL */
544 struct cdev *dev = tp->t_dev;
547 * According to POSIX, we must implement an fstat(). This also
548 * makes this implementation compatible with Linux binaries,
549 * because Linux calls fstat() on the pseudo-terminal master to
552 * XXX: POSIX also mentions we must fill in st_dev, but how?
555 bzero(sb, sizeof *sb);
557 if (psc->pts_cdev != NULL)
558 sb->st_ino = sb->st_rdev = dev2udev(psc->pts_cdev);
560 #endif /* PTS_EXTERNAL */
561 sb->st_ino = sb->st_rdev = tty_udev(tp);
563 sb->st_atim = dev->si_atime;
564 sb->st_ctim = dev->si_ctime;
565 sb->st_mtim = dev->si_mtime;
566 sb->st_uid = dev->si_uid;
567 sb->st_gid = dev->si_gid;
568 sb->st_mode = dev->si_mode | S_IFCHR;
574 ptsdev_close(struct file *fp, struct thread *td)
576 struct tty *tp = fp->f_data;
578 /* Deallocate TTY device. */
583 * Open of /dev/ptmx or /dev/ptyXX changes the type of file
584 * from DTYPE_VNODE to DTYPE_PTS. vn_open() increases vnode
585 * use count, we need to decrement it, and possibly do other
588 if (fp->f_vnode != NULL)
589 return (vnops.fo_close(fp, td));
595 ptsdev_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp)
599 kif->kf_type = KF_TYPE_PTS;
601 kif->kf_un.kf_pts.kf_pts_dev = tty_udev(tp);
602 kif->kf_un.kf_pts.kf_pts_dev_freebsd11 =
603 kif->kf_un.kf_pts.kf_pts_dev; /* truncate */
604 strlcpy(kif->kf_path, tty_devname(tp), sizeof(kif->kf_path));
608 static struct fileops ptsdev_ops = {
609 .fo_read = ptsdev_read,
610 .fo_write = ptsdev_write,
611 .fo_truncate = invfo_truncate,
612 .fo_ioctl = ptsdev_ioctl,
613 .fo_poll = ptsdev_poll,
614 .fo_kqfilter = ptsdev_kqfilter,
615 .fo_stat = ptsdev_stat,
616 .fo_close = ptsdev_close,
617 .fo_chmod = invfo_chmod,
618 .fo_chown = invfo_chown,
619 .fo_sendfile = invfo_sendfile,
620 .fo_fill_kinfo = ptsdev_fill_kinfo,
621 .fo_flags = DFLAG_PASSABLE,
629 ptsdrv_outwakeup(struct tty *tp)
631 struct pts_softc *psc = tty_softc(tp);
633 cv_broadcast(&psc->pts_outwait);
634 selwakeup(&psc->pts_outpoll);
635 KNOTE_LOCKED(&psc->pts_outpoll.si_note, 0);
639 ptsdrv_inwakeup(struct tty *tp)
641 struct pts_softc *psc = tty_softc(tp);
643 cv_broadcast(&psc->pts_inwait);
644 selwakeup(&psc->pts_inpoll);
645 KNOTE_LOCKED(&psc->pts_inpoll.si_note, 0);
649 ptsdrv_open(struct tty *tp)
651 struct pts_softc *psc = tty_softc(tp);
653 psc->pts_flags &= ~PTS_FINISHED;
659 ptsdrv_close(struct tty *tp)
661 struct pts_softc *psc = tty_softc(tp);
663 /* Wake up any blocked readers/writers. */
664 psc->pts_flags |= PTS_FINISHED;
665 ptsdrv_outwakeup(tp);
670 ptsdrv_pktnotify(struct tty *tp, char event)
672 struct pts_softc *psc = tty_softc(tp);
675 * Clear conflicting flags.
680 psc->pts_pkt &= ~TIOCPKT_START;
683 psc->pts_pkt &= ~TIOCPKT_STOP;
686 psc->pts_pkt &= ~TIOCPKT_DOSTOP;
689 psc->pts_pkt &= ~TIOCPKT_NOSTOP;
693 psc->pts_pkt |= event;
694 ptsdrv_outwakeup(tp);
698 ptsdrv_free(void *softc)
700 struct pts_softc *psc = softc;
702 /* Make device number available again. */
703 if (psc->pts_unit >= 0)
704 free_unr(pts_pool, psc->pts_unit);
706 chgptscnt(psc->pts_cred->cr_ruidinfo, -1, 0);
707 racct_sub_cred(psc->pts_cred, RACCT_NPTS, 1);
708 crfree(psc->pts_cred);
710 seldrain(&psc->pts_inpoll);
711 seldrain(&psc->pts_outpoll);
712 knlist_destroy(&psc->pts_inpoll.si_note);
713 knlist_destroy(&psc->pts_outpoll.si_note);
716 /* Destroy master device as well. */
717 if (psc->pts_cdev != NULL)
718 destroy_dev_sched(psc->pts_cdev);
719 #endif /* PTS_EXTERNAL */
724 static struct ttydevsw pts_class = {
725 .tsw_flags = TF_NOPREFIX,
726 .tsw_outwakeup = ptsdrv_outwakeup,
727 .tsw_inwakeup = ptsdrv_inwakeup,
728 .tsw_open = ptsdrv_open,
729 .tsw_close = ptsdrv_close,
730 .tsw_pktnotify = ptsdrv_pktnotify,
731 .tsw_free = ptsdrv_free,
736 #endif /* !PTS_EXTERNAL */
738 pts_alloc(int fflags, struct thread *td, struct file *fp)
742 struct pts_softc *psc;
743 struct proc *p = td->td_proc;
744 struct ucred *cred = td->td_ucred;
746 /* Resource limiting. */
748 error = racct_add(p, RACCT_NPTS, 1);
753 ok = chgptscnt(cred->cr_ruidinfo, 1, lim_cur(td, RLIMIT_NPTS));
755 racct_sub(p, RACCT_NPTS, 1);
761 /* Try to allocate a new pts unit number. */
762 unit = alloc_unr(pts_pool);
764 racct_sub(p, RACCT_NPTS, 1);
765 chgptscnt(cred->cr_ruidinfo, -1, 0);
769 /* Allocate TTY and softc. */
770 psc = malloc(sizeof(struct pts_softc), M_PTS, M_WAITOK|M_ZERO);
771 cv_init(&psc->pts_inwait, "ptsin");
772 cv_init(&psc->pts_outwait, "ptsout");
774 psc->pts_unit = unit;
775 psc->pts_cred = crhold(cred);
777 tp = tty_alloc(&pts_class, psc);
778 knlist_init_mtx(&psc->pts_inpoll.si_note, tp->t_mtx);
779 knlist_init_mtx(&psc->pts_outpoll.si_note, tp->t_mtx);
781 /* Expose the slave device as well. */
782 tty_makedev(tp, td->td_ucred, "pts/%u", psc->pts_unit);
784 finit(fp, fflags, DTYPE_PTS, tp, &ptsdev_ops);
791 pts_alloc_external(int fflags, struct thread *td, struct file *fp,
792 struct cdev *dev, const char *name)
796 struct pts_softc *psc;
797 struct proc *p = td->td_proc;
798 struct ucred *cred = td->td_ucred;
800 /* Resource limiting. */
802 error = racct_add(p, RACCT_NPTS, 1);
807 ok = chgptscnt(cred->cr_ruidinfo, 1, lim_cur(td, RLIMIT_NPTS));
809 racct_sub(p, RACCT_NPTS, 1);
815 /* Allocate TTY and softc. */
816 psc = malloc(sizeof(struct pts_softc), M_PTS, M_WAITOK|M_ZERO);
817 cv_init(&psc->pts_inwait, "ptsin");
818 cv_init(&psc->pts_outwait, "ptsout");
822 psc->pts_cred = crhold(cred);
824 tp = tty_alloc(&pts_class, psc);
825 knlist_init_mtx(&psc->pts_inpoll.si_note, tp->t_mtx);
826 knlist_init_mtx(&psc->pts_outpoll.si_note, tp->t_mtx);
828 /* Expose the slave device as well. */
829 tty_makedev(tp, td->td_ucred, "%s", name);
831 finit(fp, fflags, DTYPE_PTS, tp, &ptsdev_ops);
835 #endif /* PTS_EXTERNAL */
838 sys_posix_openpt(struct thread *td, struct posix_openpt_args *uap)
844 * POSIX states it's unspecified when other flags are passed. We
847 if (uap->flags & ~(O_RDWR|O_NOCTTY|O_CLOEXEC))
850 error = falloc(td, &fp, &fd, uap->flags);
854 /* Allocate the actual pseudo-TTY. */
855 error = pts_alloc(FFLAGS(uap->flags & O_ACCMODE), td, fp);
862 /* Pass it back to userspace. */
863 td->td_retval[0] = fd;
870 pts_init(void *unused)
873 pts_pool = new_unrhdr(0, INT_MAX, NULL);
876 SYSINIT(pts, SI_SUB_DRIVERS, SI_ORDER_MIDDLE, pts_init, NULL);